Comparison of the benzoyl-DL-arginine-naphthylamide (BANA) test, DNA probes, and immunological reagents for ability to detect anaerobic periodontal infections due to Porphyromonas gingivalis, Treponema denticola, and Bacteroides forsythus. Most forms of periodontal disease are associated with the presence or overgrowth of anaerobic species that could include Treponema denticola, Porphyromonas gingivalis, and Bacteroides forsythus among others. These three organisms are among the few cultivable plaque species that can hydrolyze the synthetic trypsin substrate benzoyl-DL-arginine-naphthylamide (BANA). In turn, BANA hydrolysis by the plaque can be associated with periodontal morbidity and with the presence of these three BANA-positive organisms in the plaque. In this investigation, the results of the BANA test, which simultaneously detects one or more of these organisms, were compared with the detection of these organisms by (i) highly specific antibodies to P. gingivalis, T. denticola, and B. forsythus; (ii) whole genomic DNA probes to P. gingivalis and T. denticola; and (iii) culturing or microscopic procedures. The BANA test, the DNA probes, and an enzyme-linked immunosorbent assay or an indirect immunofluorescence assay procedure exhibited high sensitivities, i.e., 90 ot 96%, and high accuracies, i.e., 83 to 92%, in their ability to detect combinations of these organisms in over 200 subgingival plaque samples taken from the most periodontally diseased sites in 67 patients. This indicated that if P. gingivalis, T. denticola, and B. forsythus are appropriate marker organisms for an anaerobic periodontal infection, then the three detection methods are equally accurate in their ability to diagnose this infection. The same statement could not be made for the culturing approach, where accuracies of 50 to 62% were observed.


In vitro transcription and translation of group B rotavirus strain IDIR gene 8 and immunoprecipitation by human sera. Group B rotaviruses (GBRs) are associated with episodes of acute diarrhea in humans and a variety of animal species. To date, these agents have not been well adapted to growth in tissue culture, and evaluation of human sera for antibodies directed against GBRs has been hindered by the inability to obtain standardized and highly purified preparations of GBR antigens. In order to evaluate the reactivities of antisera with a highly specific antigen, we prepared a full-length cDNA clone of gene 8 of the IDIR strain of GBR. This clone was transcribed with T7 RNA polymerase, and the resulting RNA was translated in vitro with rabbit erythrocyte lysates. The polypeptide expressed from IDIR gene 8 was specifically precipitated by antibody directed against IDIR but not by antibody directed against ADRV (adult diarrhea rotavirus) or bovine strains of GBR. Subsequent immunoprecipitation reactions confirmed the presence of anti-IDIR antibodies among the U.S. population. Of 129 human serum specimens, 3 specifically immunoprecipitated the IDIR gene 8 polypeptide.


Comparison of four techniques for detection of antibodies to cytomegalovirus. Four serological methods were compared and evaluated for use in detecting cytomegalovirus antibody in blood and organ donors. Western blotting (immunoblotting), latex agglutination, enzyme-linked immunosorbent assay, and a recent available microparticle enzyme immunosorbent assay were used. The microparticle enzyme immunoassay appears to compare favorably with each of the other three assays tested for screening blood and organ donors for a previous cytomegalovirus infection.


Development and clinical significance of a diagnostic assay based on the polymerase chain reaction for detection of human cytomegalovirus DNA in blood samples from immunocompromised patients. The presence of human cytomegalovirus (HCMV) DNA in blood was investigated by the polymerase chain reaction (PCR) in 293 blood samples from 86 immunocompromised patients. Of the 86 patients, 23 underwent clinical and virologic follow-up for HCMV infection. In parallel, blood samples were examined for viremia and antigenemia. Concordant results between PCR and assays for viremia and antigenemia were obtained on 124 positive and 110 negative samples, with an overall concordance of 79.8%, while 59 samples (most from patients with HCMV infection) were positive by PCR alone. PCR is a new powerful tool for detection of HCMV infections in blood samples from immunocompromised patients. However, its clinical significance appears to be restricted to the indication of a risk of reactivation of HCMV infection.


Evaluation of an enzyme-linked immunoassay employing a covalently bound capture antibody for direct detection of herpes simplex virus. The FDL enzyme-linked immunosorbent assay (ELISA; Fairleigh Dickinson Laboratories, Inc., Abilene, Tex.) for the detection of herpes simplex virus (HSV) makes use of a covalently attached antibody. This assay was compared with viral isolation and with the Ortho HSV Antigen Detection ELISA (Ortho Diagnostic Systems, Inc., Raritan, N.J.). One hundred forty-eight specimens were tested. The FDL ELISA identified 66 of 104 specimens from which HSV was isolated, yielding a sensitivity of 63% and a specificity of 95%. These results compared favorably with those obtained by using the Ortho ELISA. The total test time was shorter and the washing step was simpler than that with the Ortho assay, making the FDL assay an attractive alternative to similar methodologies.


Influence of animal age on the beta-adrenergic system in cultured rat aortic and mesenteric artery smooth muscle cells. It has previously been reported that aortic smooth muscle cells cultured from old rats have a marked decline in beta-adrenergic stimulated cAMP accumulation. We wished to confirm this observation and determine whether this decline was secondary to loss of beta-adrenergic receptors (BAR). Primary cultures of aortic and mesenteric artery smooth muscle cells were obtained by enzymatic digestion from young and old male Fischer 344 rats. In aortic cells from old animals, there was a decline in beta-adrenergic receptor density and a rightward shift in the dose response curve to isoproterenol without a change in maximal cAMP accumulation. In mesenteric artery cells, there were no age changes in these parameters. Beta-adrenergic receptor subtype distribution was determined and was similar between all age groups and vessel types. These findings differ from whole tissue studies and suggest that cultured smooth muscle cells have limitations as a model for the aging adrenergic system.


The extensor carpi radialis longus muscle flap for anterior elbow coverage. A muscle group resection for treatment of malignant fibrous histiocytoma of the distal arm exposed a 15 cm length of radial nerve. The soft tissue defect and radial nerve were covered with an extensor carpi radialis longus muscle island flap. The proximal dominant vascular pedicle enabled extensive mobilization and transposition of this muscle to cover the defect while preserving normal elbow, radial nerve, and hand function. Because of its ease of elevation, extensive arc of rotation, and its expendability, the extensor carpi radialis longus muscle flap should be considered as an option for reconstruction of defects about the elbow joint.


The pulp plasty: a composite graft for complete syndactyly fingertip separations. Composite grafts of skin and subcutaneous fat harvested from the glabrous non-weight-bearing areas of the foot were used to graft 34 fingertips after separation of 23 complete syndactyly webs in 13 patients. Simple complete syndactylies accounted for 17% and complex complete syndactylies accounted for 83%; synonychia was encountered in 70%. Follow-up averaged 13.9 months (minimum, 2 months, maximum 33 months). All patients had 100% take of the composite graft. Subjective gradings were 94% good, 6% fair, and there were no poor results. This technique provides a relatively normal contour and satisfactory pad to the fingertip.


Nonadjacent syndactyly in the congenital constriction band syndrome. Hand anomalies in the amniotic band sequence are frequently both complex and difficult to explain in terms of our conventional understanding of limb embryogenesis. A case manifesting pseudosyndactyly between nonadjacent fingers confirms the role of an in utero disturbance after the seventh week, in concert with close apposition between nearby but not adjacent parts.


Electrodiagnosis of Martin-Gruber connection and its clinical importance in peripheral nerve surgery. We propose new criteria for the electrodiagnosis of Martin-Gruber connection. Forty-seven patients with cubital tunnel syndrome were studied, and 8 (17%) were found to have a Martin-Gruber connection. Eighty-seven patients without cubital tunnel syndrome were also studied, and 14 (16%) had a Martin-Gruber connection. The rate of occurrence of the anastomosis in these two groups was approximately the same. No sensory communication was demonstrated, and the lateral intrinsic muscles received more innervation from the communicating branch than the hypothenar muscles. The entry point of the crossing fiber from the median nerve to the ulnar nerve was 3 to 10 cm distal to the medial humeral epicondyle, and there may be a significant risk of injury in ulnar nerve transposition.


Sensory recovery after median nerve grafting. Fourteen patients were evaluated prospectively after median nerve grafts. Twelve male and two female patients with a mean age of 41 years were included. Mean time since surgery was 4 years. Detailed sensory evaluations were completed. Statistical evaluation analyzed relationships between object identification, sensory tests, and graft length. According to the S-0 to S-4 grading system, 11 patients were considered to be S-3+ or greater. Recovery of moving two-point discrimination of 2 to 3 mm. was achieved by 50% of the patients. Strong correlations were found between object identification and static two-point discrimination, moving two-point discrimination, and graft length. Cutaneous pressure threshold and vibration threshold correlated weakly with object identification.


Radial nerve rupture after a traction injury: a case report. A case in which a patient sustained a closed rupture of the radial nerve at the lateral intramuscular septum from a traction injury is presented. No humeral fracture occurred, and the patient regained substantial function after delayed primary repair.


Functional and biochemical characterization of a calcium-ionophore-induced state of unresponsiveness in a cytolytic T cell clone. To characterize the requirements for the induction of an anergic state in immunocompetent cells we examined the effect of an increase in intracellular calcium concentration on the subsequent responsiveness of cytolytic T cells to antigenic stimulation in vitro. Pretreatment of a murine cytolytic T cell clone with the calcium-ionophore A23187 resulted in the induction of an anergic state characterized by a decrease in cytolytic activity and granule exocytosis upon Ag-specific stimulation. Furthermore, IFN-gamma synthesis declined whereas de novo synthesis of a yet unidentified protein with a molecular mass of 33 kDa as well as proliferative response of cells in response to exogenous IL-2 were unaffected. This state of partial unresponsiveness 1) could be prevented by concomitant pretreatment of cells with cyclosporin A or protein synthesis inhibitors and 2) was reversible within 48 h. Biochemical analysis of TCR-induced intracellular activation revealed a block in signal transduction before the activation of protein kinase C because cellular unresponsiveness could be bypassed by the phorbol ester PMA plus the calcium-ionophore A23187. However, phosphatidylinositol turnover was markedly inhibited in unresponsive cells that also did not show a calcium influx on stimulation with concanavalin A. We conclude that a rise in intracellular calcium in cytolytic T cells might not only be necessary for cellular activation but may also trigger the induction of a partial unresponsiveness to antigenic stimulation due to an inhibition in the early phase of signal transduction.


IFN-gamma induces expression of Fc gamma RIII (CD16) on human eosinophils. The extent to which eosinophils constitutively express FcRIII (CD16) is controversial. We were unable to detect this receptor on freshly isolated, peripheral blood eosinophils. The capacity of eosinophils to change their Fc gamma R expression in vitro has not been previously demonstrated. Culture with IFN-gamma for 1 to 2 days induced FcRIII expression on eosinophils. This effect was dose-dependent and significant at concentrations of 100 U/ml IFN-gamma and above. Expression of FcRI (CD64) and FcRII (CDw32) was also upregulated. These increases were inhibited by cycloheximide (10(-6) M), suggesting a requirement for protein synthesis, and dexamethasone (10(-6) M). Northern blot analysis demonstrated the presence of FcRIII mRNA in eosinophils cultured with IFN-gamma for 2 days but not in unstimulated eosinophils. By contrast, culture with IL-3 caused an up-regulation of eosinophil FcRII expression but did not induce expression of FcRI or FcRIII. The FcRIII expressed by eosinophils after IFN-gamma stimulation was functionally active, as shown by the triggering of eosinophil membrane depolarization and LTC4 generation by an anti-CD16 mAb. Treatment of IFN-gamma-stimulated eosinophils with phosphatidylinositol-specific phospholipase C reduced FcRIII expression, suggesting that, like neutrophils, eosinophils express the phosphatidylinositol glycan-linked form of this receptor. Therefore, this study demonstrates that IFN-gamma-treated eosinophils express a functionally active, phosphatidylinositol glycan-anchored form of FcRIII.


Protective effects of soluble CR1 in complement- and neutrophil-mediated tissue injury. Complement activation is an important step for triggering of acute inflammatory reactions. Soluble human recombinant complement receptor type 1 (sCR1) blocks complement activation by both classical and alternative pathways. In addition to glycogen-induced peritonitis, three models of complement-dependent acute inflammatory injury have been used to assess the protective effects of sCR1: lung and dermal injury after intraalveolar or intradermal deposition of IgG immune complexes; acute lung injury resulting from intravascular activation of complement after the i.v. injection of cobra venom factor; and acute skin and lung injury (at 4 h) after thermal trauma involving 25 to 30% total body surface area. Vascular injury was quantified by increases in vascular permeability, hemorrhage, neutrophil infiltration, and, as indicated, tissue water content. Intravenous infusion of sCR1 reduced lung and dermal vascular injury in all models studied. In glycogen-induced peritoneal exudates sCR1-reduced neutrophil accumulation by 79%. In animals undergoing IgG immune complex-induced alveolitis, sCR1 treatment reduced vascular permeability and hemorrhage by 72 and 71%, respectively, and tissue accumulation of neutrophils was reduced by 68%. After cobra venom factor injection, sCR1 reduced increases in lung vascular permeability by 67%, hemorrhage by 73%, and lung myeloperoxidase content by 55%. Four hours after thermal injury of skin, sCR1-treated animals demonstrated significant protection against lung injury; increases in vascular permeability and hemorrhage were reduced by 45 and 46%, respectively, and myeloperoxidase content was lowered by 39%. In thermal injury of the skin, sCR1 injection reduced dermal vascular permeability by 25% at 1 h (p = NS) and 44% at 4 h. Water content in skin biopsies was also decreased. There was a dose-response relationship between the amount of sCR1 infused and the extent of protection in each of the injury models. These data demonstrate that sCR1 offers significant protection against complement-dependent tissue injury in the animal models studied and that the protective effects are related to reduced neutrophil content.


Transcriptional regulation of the human IgE receptor (Fc epsilon RII/CD23) by EBV. Identification of EBV-responsive regulatory elements in intron 1. EBV infection of B cells induces the B cell activation Ag, CD23 (Fc epsilon RII). CD23 remains constitutively expressed at high levels in all EBV-immortalized B cells and likely plays an important role in the initiation and maintenance of immortalization by EBV. By utilizing an EBV-negative Burkitt's lymphoma line (BJAB) and EBV-positive sublines derived from it by in vitro infection, we have examined the molecular mechanisms involved in the regulation of CD23 by EBV. By nuclear runoff analysis, we have found that induction of CD23 is mediated by transcriptional activation that occurs in the presence of the transformation-competent B958 virus but not in the presence of the nontransforming P3HR-1 strain of EBV. To identify EBV-responsive transcriptional regulatory elements of CD23, we have performed reporter gene assays using plasmids containing fragments of the CD23 gene derived from its 5' terminus and adjacent flanking region transfected into EBV-positive and -negative BJAB lines. We have identified a 534-bp fragment of the gene which enhances transcription from a heterologous promoter (SV40) and reporter gene (chloramphenicol acetyltransferase) only in the presence of transformation-competent strains of EBV. Deletion of 144 bp of intron 1 from the 3' end of this fragment results in loss of EBV-responsive enhancer activity. The finding of an EBV-responsive enhancer element of CD23 is supported by mobility shift assays that demonstrated the formation of specific DNA-protein complexes between nuclear protein from transforming EBV-positive cells and the 144-bp intron sequence. These studies suggest that the transcriptional activation of CD23 by transforming strains of EBV involves regulatory elements that are located within the first intron of the gene.


Placebo-controlled clinical trial of sodium stibogluconate (Pentostam) versus ketoconazole for treating cutaneous leishmaniasis in Guatemala. To determine the relative efficacy and toxicity of stibogluconate and ketoconazole for the treatment of cutaneous leishmaniasis, a comparative trial was conducted in which 120 Guatemalan men with parasitologically proven cutaneous leishmaniasis were randomly divided into three treatment groups: sodium stibogluconate (20 mg of antimony per kilogram per day intravenously for 20 days), ketoconazole (600 mg per day orally for 28 days), and placebo. Treatment outcome was influenced by species. Among patients infected with Leishmania braziliensis, 24 (96%) of 25 in the stibogluconate group but only 7 (30%) of 23 in the ketoconazole group responded. Among Leishmania mexicana-infected patients, only 4 (57%) of 7 in the stibogluconate group but 8 (89%) of 9 in the ketoconazole group responded. These differences emphasize the importance of speciation in the treatment of leishmaniasis.


Failure of prophylactic ganciclovir to prevent cytomegalovirus disease in recipients of lung transplants. In an effort to prevent cytomegalovirus (CMV) pneumonitis, seven consecutive CMV-seronegative lung transplant recipients of organs from seropositive donors (D+/R-) were given ganciclovir, 2.5-5 mg/kg intravenously twice daily for the first 10-21 days after transplantation, and commercial polyvalent immune globulin, 200-400 mg/kg every 7-14 days intravenously, for the first 2-3 weeks after transplantation. This regimen was followed by oral acyclovir. Six patients developed CMV viremia and all developed CMV pneumonitis. Viremia occurred later in these patients compared with D+/R- patients who received alternative forms of CMV prophylaxis or CMV-seropositive recipients who received no specific prophylaxis (P = .023 and P = .021, respectively). There was no statistical difference in incidence or time to onset of CMV pneumonitis. When given as described, prophylactic ganciclovir and immune globulin followed by oral acyclovir may have delayed CMV viremia but did not prevent it or pneumonitis in high-risk lung transplant recipients.


Contribution of single genes within the unique short region of Aujeszky's disease virus (suid herpesvirus type 1) to virulence, pathogenesis and immunogenicity. Pigs (3 and 10 weeks old) were infected intranasally with Aujeszky's disease virus (ADV) mutants that functionally lacked one of the non-essential genes in the unique short region of the genome (except the gene encoding the 11K protein). Virus excretion in oropharyngeal fluid and disease symptoms were monitored. Some pigs were killed to study pathogenesis, whereas others were challenged with virulent ADV 8 weeks after the primary infection. Mutants lacking protein kinase, or glycoproteins gp63 or gI showed reduced virulence, but mutants lacking gX or the 28K protein showed normal virulence. Glycoprotein gI appears to affect the tissue tropism of ADV in pigs, presumably by facilitating the spread of the virus through the central nervous system. In this study, there was no correlation between virulence and virus multiplication in either cultured cells or in the oropharynx in vivo. All mutants induced neutralizing antibody and complete or partial protection against challenge infection. Complete protection was obtained by inoculation with the gI and gX mutants, whereas incomplete protection was obtained using gp63 and protein kinase mutants. Complete clinical and virological protection was associated with the absence of secondary antibody responses in the serum.


Processing of human cytomegalovirus envelope glycoproteins in and egress of cytomegalovirus from human astrocytoma cells. The synthesis of human cytomegalovirus (HCMV) envelope glycoproteins and the production of infectious HCMV in human astrocytoma and skin fibroblast (SF) cells were analysed. HCMV envelope glycoproteins synthesized in astrocytoma cells had lower Mrs than the same glycoproteins synthesized in SF cells regardless of the strain of HCMV used, showing that the differences observed were due to differences in processing by the host cell and not the strain of HCMV used. HCMV envelope glycoproteins synthesized in astrocytoma cells were found to contain less galactosamine. Moreover, when synthesized in SF cells some HCMV glycoproteins contained a protease-resistant fragment owing to the presence of a cluster of O-linked oligosaccharides on the polypeptide. This fragment was not present when these HCMV glycoproteins were synthesized in astrocytoma cells. These data suggested that HCMV glycoproteins synthesized in astrocytoma cells contain fewer O-linked oligosaccharides. In contrast, other post-translational events such as proteolytic cleavage of the HCMV gB glycoprotein and the formation of disulphide-linked complexes did occur. The virus produced in astrocytoma cells was capable of infecting SF cells, suggesting that complete O-glycosylation is not needed to produce infectious HCMV. However, astrocytoma cells were slow to release virus into the culture medium, suggesting that a fully functional Golgi network is needed for efficient egress of HCMV from the host cell.


Characterization of enveloped tegument structures (L particles) produced by alphaherpesviruses: integrity of the tegument does not depend on the presence of capsid or envelope. Recent studies have shown that infection with herpes simplex virus type 1 (HSV-1) strain 17 generates in addition to virions a novel type of non-infectious particle. These particles, termed L particles, lack capsids and viral DNA, and consist predominantly of tegument and envelope proteins. We show that L particle production is not restricted to one strain of HSV-1, and that pseudorabies virus and equine herpesvirus type 1 also release particles which are similar in composition to and morphologically indistinguishable from HSV-1 L particles. Data obtained from monoclonal antibody analysis revealed that Vmw175, an immediate early HSV-1 polypeptide which had been previously identified as a virion component, is located predominantly in L particles and not in virions. Following removal of the envelope from L particles, the remaining tegument material largely retained its structural integrity, indicating that the structure of the tegument does not depend on the presence of the capsid or envelope.


Assembly of enveloped tegument structures (L particles) can occur independently of virion maturation in herpes simplex virus type 1-infected cells. Cells infected with a number of alphaherpesviruses produce non-infectious virion-related particles, termed L particles, in addition to infectious virions. L particles consist of the tegument and envelope components, but lack the virus capsid and DNA. Using a herpes simplex virus type 1 (HSV-1) temperature-sensitive mutant, ts1201, which fails to produce mature virions, we show that L particle production is independent of virion formation. Moreover, the quantity and protein composition of L particles generated by this mutant at the non-permissive temperature are indistinguishable from those produced in wild-type HSV-1 infections. Electron microscopy studies suggest that the processes governing the assembly of tegument and envelope components into L particles are similar to those involved in virion maturation.


Analysis of intrastrain recombination in herpes simplex virus type 1 strain 17 and herpes simplex virus type 2 strain HG52 using restriction endonuclease sites as unselected markers and temperature-sensitive lesions as selected markers. The viral and host factors involved in herpes simplex virus (HSV) recombination are little understood. To identify features of the process, recombination in HSV-1 and HSV-2 has been studied by analysing the segregation of unselected markers in the form of restriction endonuclease (RE) sites. By confining parental interactions to only one strain of virus of each serotype, restrictions imposed by non-homology are overcome and differential growth phenotypes can be discounted. The analysis of unselected and selected recombinants using RE sites in conjunction with temperature-sensitive mutations is consistent with (i) HSV being highly recombinogenic, (ii) parental and progeny molecules taking part in the process, (iii) the four genomic isomers participating in recombination, (iv) genome alignment being part of the recombination process and (v) cellular factors in conjunction with genome homology influencing the efficiency of recombination.


The UL13 virion protein of herpes simplex virus type 1 is phosphorylated by a novel virus-induced protein kinase. Herpes simplex virus type 1 (HSV-1) induces a protein kinase (PK) activity in infected cell nuclei. In vitro, the enzyme is able to phosphorylate exogenous casein (albeit inefficiently) but not protamine, can use ATP or GTP as a phosphate donor, is stimulated by high salt concentrations and is insensitive to inhibition by heparin. On the basis of these properties, the PK appears to be distinct from previously described cellular enzymes and from the cytoplasmic PK encoded by the viral US3 gene. A major substrate of the enzyme in vitro is a virus-induced protein with an Mr of 57000 (Vmw57). The gene encoding Vmw57 was mapped using recombinants between HSV-1 and HSV-2 to a region of the virus genome containing genes UL9 to UL15. Use of a monospecific rabbit antiserum showed that Vmw57 is a virion structural protein encoded by gene UL13. These results, in conjunction with previous reports that the UL13 protein contains PK sequence motifs, support the notions that the nuclear PK and Vmw57 are identical, and that the observed reactivity is due to autophosphorylation.


Herpes simplex virus type 1 origin-dependent DNA replication in insect cells using recombinant baculoviruses. The minimal set of seven herpes simplex virus type 1 (HSV-1) genes required for viral origin-dependent DNA synthesis was previously identified using a transient replication assay in a mammalian cell line permissive for HSV-1 growth. We have constructed recombinant baculoviruses which efficiently express the products of each of these seven genes in infected Spodoptera frugiperda (Sf) insect cells. When Sf cells were transfected with a plasmid containing a functional HSV-1 origin of replication, and subsequently superinfected with a mixture of these seven viruses, the input plasmid was amplified. This amplification exhibited properties characteristic of genuine HSV-1 DNA replication: all seven HSV-1 replication gene products were required, replicated DNA was detected as concatemers, and mutated origins were impaired to similar extents in insect cells and cells permissive for HSV-1 replication. These results demonstrate that the HSV-1 proteins expressed in Sf cells are fully competent for viral DNA synthesis, and indicate that any host function essential in mammalian cells must also be present in the infected insect cells. This system also provides a convenient method by which mutated replication proteins can be screened for function and produced in amounts sufficient for biochemical studies. Using this approach we show that the ability of the UL9 protein to bind to the viral origins of replication is not sufficient for it to facilitate DNA synthesis.


The effect of cicloxolone sodium on the replication of vesicular stomatitis virus in BSC-1 cells. The effect of cicloxolone sodium (CCX) on the replication of vesicular stomatitis virus (VSV) was investigated. The drug was active during all stages of the virus replication cycle, indicating that it does not operate by the specific inhibition of any single essential virus gene product. The drug reduced the number of VSV particles assembled and released by 100- to 1000-fold. Infectious virus yield was reduced 1000- to 10000-fold, giving a 10-fold or greater increase in the particle/p.f.u. ratio. The reduced number of virus particles produced in the presence of CCX results from two superimposed effects: suppression of VSV secondary transcription and viral protein synthesis, and perturbation of virion assembly. The inhibition of VSV assembly is due to impairment of a Golgi apparatus function related to transport of VSV glycoprotein G to the cell surface, and is characterized by accumulation of viral G and M proteins within the cell. Incubation of VSV-infected cells in the presence of two glycosylation inhibitors, tunicamycin and monensin, similarly leads to intracellular accumulation of G and M proteins, suggesting a common mechanism of action affecting VSV virion assembly. The differential effect of CCX concentration on intracellular levels of the L, N and NS proteins was analysed. CCX also possesses a virucidal effect on mature infectious VSV particles in suspension, 300 microM reducing the VSV titre about 10-fold in 24 h at 4 degrees C or 37 degrees C. The mode of antiviral activity against VSV is compared with that against herpes simplex virus.


The effect of cicloxolone sodium on the replication in cultured cells of adenovirus type 5, reovirus type 3, poliovirus type 1, two bunyaviruses and Semliki Forest virus. The effect of cicloxolone sodium (CCX) on the replication of typical representatives of different virus families [adenovirus type 5 (Ad-5), reovirus type 3 (Reo-3), Bunyamwera and Germiston viruses, poliovirus type 1 (Polio-1) and Semliki Forest virus (SFV)] in tissue culture was investigated. The Golgi apparatus inhibitor monensin (Mon) and CCX were shown to have analogous effects on some aspects of virus replication. Although the Mon-like effect of CCX played no role in the antiviral activity against Ad-5, Reo-3 or Polio-1, it could entirely account for the antiviral activity against the Bunyamwera and Germiston viruses, for which inhibition of glycoprotein processing was responsible for the antiviral activity. In the case of SFV, the Mon-like activity of CCX caused cytoplasmic assembly of fully infectious SFV within vacuoles and thus impaired virus release without altering total infectious virus yield. Fewer Ad-5 and Reo-3 progeny were produced in the presence of the drug. CCX had a dose-dependent biphasic effect on the particle:p.f.u. ratio of the Reo-3 yield. At low CCX concentration (less than 50 microM) the virus yield contained poor quality, non-infectious virus, but at higher CCX concentration (greater than or equal to 100 microM) low quality virus could no longer be successfully assembled. We conclude that the antiviral effect can be manifested in three ways: (i) by a reduction in the virus particle yield produced; (ii) by a loss of quality (relative infectivity); (iii) by a virucidal effect of the drug. We have previously defined three CCX sensitivity classes. Mechanisms (i), (ii) and (iii) operate against viruses belonging to class CCXs-1 [herpes simplex virus (HSV) type 1, HSV-2 and vesicular stomatitis virus], but essentially only (i) and (ii) affect Reo-3 (CCXs-2), whereas (i) and possibly (iii) affect Ad-5 (CCXs-2). In the case of SFV (CCXs-3) none of these mechanisms operate, but relocation of assembled virus is found.


Human papillomavirus type 6a DNA in the lung carcinoma of a patient with recurrent laryngeal papillomatosis is characterized by a partial duplication. Transcriptionally active human papillomavirus type 6a (HPV-6a) DNA was detected in a lung carcinoma of a patient with recurrent laryngeal papillomatosis. The carcinoma contained episomal HPV-6a genomes that had a duplication of the upstream regulatory region, the late region and a portion of the early region. HPV-6a genomes found in benign laryngeal papillomas from the same patient did not contain this duplication. A role for the mutant molecules in the pathogenesis of the malignancy is suggested.


Repression of human cytomegalovirus major immediate early gene expression in a monocytic cell line. We have previously shown that a major site of persistence of human cytomegalovirus (HCMV) in healthy carriers is in peripheral blood monocytes. However, monocytes are difficult to infect in vitro with HCMV, and HCMV gene expression cannot be reproducibly detected in peripheral blood cells of healthy carriers. Here we show that the monocytic cell line THP1 is non-permissive for HCMV infection due to a block in expression of the HCMV major immediate early (IE) promoter. This repression is correlated with the presence of a differentiation-specific cellular factor which binds to the imperfect dyad symmetry and the 21 bp enhancer repeats of the major IE promoter regulatory region and which has characteristics of MBF1, a factor which we have previously defined in HCMV non-permissive, undifferentiated teratocarcinoma cells. Both differentiation of THP1 cells into macrophages, which results in a decrease in this factor, or deletion of the factor's binding sites from the IE promoter/enhancer lifts this repression and permits expression from the major IE promoter.


Nuclear expression of the lower matrix protein of human cytomegalovirus in peripheral blood leukocytes of immunocompromised viraemic patients. Peripheral blood leukocytes (PBL), namely polymorphonuclear leukocytes (PMNL), are the major carrier of human cytomegalovirus (HCMV) in the blood of immunocompromised patients with HCMV viraemia. By using monoclonal antibodies (MAbs) directed against different early and late viral proteins, we showed that the protein accumulating in PBL, originally reported to be an immediate early (IE) gene product, is the 65K lower matrix early structural protein (ep65). This protein is detectable by immunofluorescence before IE proteins during early stages of the replication cycle of HCMV in permissive human embryonic lung fibroblast cells. However, the appearance of ep65 in the nucleus within 1 h post-infection in the presence of cycloheximide indicates that it represents uptake from the virus inoculum rather than newly synthetized protein. The ep65 MAbs staining PBL did not react with Vero cells infected with a recombinant vaccinia virus encoding the major IE gene (IE1) product, whereas MAbs reactive with the 72K major IE protein stained only faintly a small number of infected PBL. A group of four ep65 MAbs was tested in competitive binding assays to show that ep65 possesses at least three distinct epitopes. These were recognized by all four MAbs in AD169-infected Vero cell cultures when fixed with formaldehyde, whereas only one MAb recognizing a distinct epitope was reactive with methanol-acetone (MA)-fixed AD169-infected Vero cells. In formalin-fixed PBL the number of infected cells stained by the four ep65 MAbs was about twofold that found using MA-fixed cells. Using fluorescence-activated cell sorter-purified leukocyte subpopulations from viraemic patients with different levels of viraemia, the ratio of ep65-positive to ep65-negative cells was found to be 1:100 to 1:100,000 for PMNL, and only 1:10,000 to 1:100,000 for mononuclear cells.


Analysis of human herpesvirus 6 glycoproteins recognized by monoclonal antibody OHV1. A virus-specific glycoprotein (gp) from human herpes-virus 6 (HHV-6) was studied using the anti-HHV-6 monoclonal antibody OHV1. Immunoprecipitation with extracts from infected cells revealed that the antibody recognized four glycosylated proteins (gps) with Mrs of 106K, 102K, 65K and 63K under reducing conditions. However, only two gps, of 106K (gp106) and 102K, were detected under non-reducing conditions. Pulse-chase experiments revealed that gp65 and gp63 were cleavage products of gp106 and gp102. When infected cells were treated with tunicamycin, none of these gps was detected. With endo-beta-N-acetylglucosaminidase H (endo H) and endo-beta-N-acetylglucosaminidase F (endo F) treatment, gp106 and gp102 disappeared. Moreover, gp65 and gp63 were not affected by endo H treatment but were sensitive to endo F treatment. These data suggest that sugar residues of gp106 and gp102 are high-mannose type N-linked oligosaccharides, whereas those of gp65 and gp63 are complex type N-linked oligosaccharides.


Protective immunization against Epstein-Barr virus-induced disease in cottontop tamarins using the virus envelope glycoprotein gp340 produced from a bovine papillomavirus expression vector. Inoculation with Epstein-Barr virus (EBV) induces malignant lymphomas in the cottontop tamarin (Saguinus oedipus oedipus). This provides an experimental animal model for assessing the efficacy of candidate EBV vaccines which are intended to reduce the incidence of human tumours associated with EBV infection. Previous work has shown that experimental vaccines based on the major virus envelope glycoprotein gp340 prepared from the membranes of EBV-infected cells are effective in protecting cottontop tamarins against EBV-induced disease. However, not all purified gp340 preparations induce protective immunity against EBV lymphoma in the tamarin. In this work, cottontop tamarins were immunized with recombinant gp340, produced using a bovine papillomavirus (BPV) expression vector, and a threonyl muramyl dipeptide adjuvant formulation. Although the recombinant-derived gp340 lacked the membrane anchor sequence of authentic gp340 and was expressed in mouse cells, it was immunogenic and induced virus-neutralizing antibodies. Healthy vaccinated tamarins were protected against EBV-induced disease. The demonstration that a recombinant gp340 product is able to elicit protective immunity in the cottontop tamarin is a significant step in the development of an EBV vaccine because previously it had not been clear whether a recombinant product would have the exact tertiary structure, including the necessary carbohydrate components, to induce protective immunity. A recombinant gp340 vaccine offers various advantages over production of the authentic molecule by laborious biochemical separation, including lower cost and the absence of potentially oncogenic EBV DNA. Therefore, recombinant gp340 produced using the BPV expression vector is suitable for development as a candidate EBV vaccine for a human Phase I trial and beyond.


One-step typing of Epstein-Barr virus by polymerase chain reaction: predominance of type 1 virus in Japan. The prevalence of two types of Epstein-Barr virus (EBV) in Japan was studied by using the polymerase chain reaction (PCR). The U2 region encoding EBV nuclear antigen 2 (EBNA-2) was chosen as the target of amplification. Consensus primers were synthesized from sequences common to the two types but encompassing a large stretch of deletion in the sequence of type 1 EBV. The primers were capable of amplifying both types at the same time but allowed differentiation of each type by the size of the amplification products. Thus we could carry out detection and typing of EBV in a one-step PCR. EBV was detected in mouth washings of 21 (23%) of 91 seropositive healthy adults. Twenty samples (22%) contained type 1 and only one (1%) type 2. Seventy-nine patients suffering from various types of tonsillitis were also studied. EBV was detected in mouth washings of 37 patients (47%). Thirty-four (43%) contained type 1 and three (4%) type 2. Double infection was not seen in either healthy donors or patients. These results indicate that type 1 EBV is highly dominant and the type 2 variant is quite rare in Japan.


Prevalence of the A and B types of Epstein-Barr virus DNA in nasopharyngeal carcinoma biopsies from southern China. Epstein-Barr virus (EBV) exists in the human population in two genetic forms, usually referred to as type A and type B. Although many earlier studies had indicated that the A type was generally predominant, there were suggestions that the B type may exhibit a preferential tropism for nasopharyngeal epithelial cells. This study examines the prevalence of the two forms of EBV DNA present in nasopharyngeal carcinoma biopsies obtained from the high incidence area of Southern China. The results obtained by Southern blot or polymerase chain reaction analyses show that in this patient group the A type of EBV is predominant.


Identification and characterization of the virion-induced host shutoff product of herpes simplex virus gene UL41. The virion-induced host shutoff product of the herpes simplex virus UL41 gene is required for shutoff of host translation and degradation of cellular mRNAs. We employed a rabbit antipeptide antiserum to identify a 58K UL41-related phosphoprotein in infected cells. We also provide evidence that this protein is a component of the virus particle, consistent with its role in virion-induced shutoff.


Characteristics of intravenous drug users by history of arrest and treatment for drug use. Typically, intravenous drug users are studied by drawing samples from drug treatment programs, from the criminal justice system, or by outreach into the street community via anthropological or ethnographic methods. Among 1405 subjects recruited through extensive community outreach, 46% reported no history of treatment for drug abuse and 16% said they had not been arrested in the preceding 10 years; 130 (9%) reported neither history. A history of arrest was higher among men and those with a history of: treatment for drug abuse, low educational attainment, having received public assistance, and unemployment. A history of drug treatment was higher among women and those of an older age with a history of: arrest, having received public assistance, and a greater duration and intensity of intravenous drug use. Intravenous drug users who had neither a history of arrest since 1977 nor of drug treatment were more likely to be women and more educated, to have not received public assistance, and to inject less than weekly. These data indicate that characteristics of intravenous drug users differ by history of arrest and treatment, substantiating reports of heterogeneity among intravenous drug users.


Peripheral neuropathy in essential mixed cryoglobulinaemia. The prevalence of various forms of peripheral neuropathy has not been previously assessed in large series of patients with essential mixed cryoglobulinaemia (EMC). Clinical and electrophysiological signs of peripheral neuropathy were observed in 21 of 37 EMC patients, consisting of polyneuropathy in 19, mononeuropathy or multiple mononeuropathy in eight, and both in six. The various forms of peripheral neuropathy occurred differently in the subgroups of EMC. Isolated polyneuropathy was more common with type II (eight of 10) than type III EMC (two of eight). Multifocal neuropathy, in association with polyneuropathy, was the most common form in type III EMC (five of eight). Patients with peripheral neuropathy and type II EMC were significantly older than type II EMC patients without neuropathy, regarding present age and age of onset of EMC. Patients with peripheral neuropathy and type III EMC tended to have higher values of ESR and IgM than type III EMC patients without neuropathy. Electrophysiological findings and sural nerve biopsy specimens (nine cases) showed prominent axonal changes. Vascular changes included vasculitis and alterations of the endoneurial microvessels in type II and type III EMC. Our findings suggest that distinct pathogenic factors are implicated in the subgroups of cryoglobulinaemic neuropathy, possibly inducing different types of vascular changes underlying polyneuropathy or, respectively, mononeuropathy and multiple mononeuropathy.


Autonomic dysfunction in diphtheritic neuropathy. Sympathetic and parasympathetic function and somatic nerve conduction were assessed in ten patients with diphtheritic neuropathy and 28 controls. None of the patients had postural hypotension. The Valsalva ratio was abnormal in two patients who also had myocarditis, but it was normal in five cases. Cardiac vagal dysfunction was found in five patients. One case showed cardiac parasympathetic denervation despite normal conduction velocity in the limbs.


Immunohistochemical demonstration of the Epstein-Barr virus-encoded latent membrane protein in paraffin sections of Hodgkin's disease. Paraffin sections from 46 cases of Hodgkin's disease were examined for the presence of the Epstein-Barr virus (EBV)-encoded latent membrane protein (LMP) using a sensitive (double layer alkaline phosphatase-anti-alkaline phosphatase) immunohistochemical method. LMP was detected in 22 cases, the majority of positive cases being of nodular sclerosis (12/24), mixed cellularity (6/7), and lymphocyte depletion (3/3) subtypes. Only one of 12 cases of lymphocyte predominant disease was positive. In all cases, reactivity was confined to Hodgkin's and Reed-Sternberg cells. These results provide further evidence for an association between EBV and Hodgkin's disease and indicate that LMP may be readily detected in archival material.


alpha B crystallin expression in non-lenticular tissues and selective presence in ubiquitinated inclusion bodies in human disease. alpha B crystallin is a lens protein which has homology with the small heat-shock proteins and is also expressed in non-lenticular tissues. Polyclonal antibodies have been raised to a synthetic peptide corresponding to residues 1-10 of alpha B crystallin. The antiserum detects a 20 kDa polypeptide on nitrocellulose replicas after polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulphate of extracts of heart muscle known to be rich in alpha B crystallin. Staining of normal human tissues reveals immunoreactivity of lens capsular epithelium, skeletal muscle, cardiac muscle, smooth muscle, renal tubular epithelium, Schwann cells, and glial cells, as has been described by other workers. In addition, positive staining of normal thyroid epithelium, colonic epithelium, and stratified squamous epithelium was seen. Tissues known to contain ubiquitinated inclusion bodies were immunostained with the anti-alpha B-crystallin antiserum. Staining of cortical Lewy bodies, astrocytic Rosenthal fibres, and hepatic Mallory bodies was seen, but only a proportion of inclusions were positive. Neurones containing the ubiquitinated inclusions of Alzheimer's disease were only very rarely immunostained and the ubiquitinated inclusions of motor neurone disease were not detected by the antiserum. Reactive astrocytes in cerebral tissues were strongly immunostained. The results suggest that alpha B crystallin is involved in the formation of ubiquitinated inclusion bodies that have associated intermediate filaments and support previous observations on the localization of a brain-specific ubiquitin carboxy-terminal hydrolase which similarly divides ubiquitinated filamentous inclusions in the central nervous system into two main groups.


Evaluation of renal scars by technetium-labeled dimercaptosuccinic acid scan, intravenous urography, and ultrasonography: a comparative study. The objective of our prospective study was to compare the sensitivity and specificity of ultrasonography, intravenous pyelography, and dimercaptosuccinic acid scan in detecting scarred kidneys. Twenty-seven consecutive subjects with recurrent urinary tract infections, vesicoureteral reflux, scarred kidneys, or a combination of these problems had all three imaging procedures performed. With the total number of scars serving as the gold standard, the sensitivity (94%) and specificity (100%) in identifying renal scars in children were highest for the DMSA scan. Intraobserver (95%) and interobserver (90%) reliability were also high for the DMSA scan. However, the clinical interpretation of the increased sensitivity of the DMSA scan is unknown. Changes on the scan not identified by intravenous urography may not represent true scars. Research into the long-term significance of these scars is indicated.


Mother-to-infant transmission of hepatitis C virus. Prospective studies of an infant of a mother infected with hepatitis C virus indicated that an HCV infection developed in the infant in early life. Perinatal transmission appeared to be the most likely explanation.


Treatment of aggressive cytomegalovirus retinitis with ganciclovir in combination with foscarnet in a child infected with human immunodeficiency virus. Ganciclovir and foscarnet are both effective for cytomegalovirus retinitis in patients with acquired immunodeficiency syndrome, but the benefits of either agent given alone are limited. A child infected with human immunodeficiency virus who had cytomegalovirus retinitis that progressed despite treatment with either agent alone received the combination of ganciclovir and foscarnet. This treatment resulted in a sustained clinical response.


Microleakage between different types of base materials. This study investigated the sealing properties of various combinations of base materials. Three chemically cured and three light-activated base materials were combinationally used to make 15 sample groups. The samples were thermocycled and immersed in 0.05% crystal violet solution for 1 hour. They were then embedded in clear casting resin, sectioned, and photographed. The interfaces of the samples were digitized. The ratio of the total interface length to the penetration of leakage was calculated and compared. The results indicated that the combination of Cavalite and VLC Dycal materials had the least microleakage and was significantly different from the other 14 groups.


Identifying human papillomavirus subtypes in cervical biopsies with in situ DNA hybridization with biotinylated probes. To test the utility of biotinylated DNA probes against various subtypes of human papillomavirus (HPV), we performed in situ DNA hybridization on routinely processed archival material from 30 patients with serial cervical biopsies including conization (group I) and a prospective group of 35 patients whose cervical biopsies showed various degrees of koilocytotic atypia and/or dysplasia (group II). Commercially available biotinylated probe cocktails against HPV types 6 and 11, 16 and 18, and 31, 35 and 51 were detected via the avidin-biotin horseradish peroxidase technique. Virus was found in 87% (26/30) of group I and 57% (20/35) of group II. Almost exclusively, viral types 16, 18, 31, 35 and 51 were detected in group I; 54% (19/35) of group II stained for types 16, 18 or 31, 35 and 51; 2.9% (1/35) stained for types 6 and 11. Nine percent of group II (3/35) showed coinfection with types 16, 18 and 31, 35 and 51. Three of six vulvar condylomata (50%) stained for types 6 and 11. In general, weaker staining was associated with greater dysplasia. In situ hybridization using biotinylated DNA probes is useful in identifying patients infected with dysplasia/carcinoma-associated HPV subtypes and can be performed easily on routine surgical specimens.


Human papillomavirus in women. A three-year experience in a county hospital colposcopy clinic. The human papillomavirus (HPV) has been associated with cervical dysplasia and carcinoma. This report summarizes the authors' experience with HPV-related problems over three years, 1987-89, while managing 1,644 women at a county hospital colposcopy clinic. Probes for HPV DNA were not used, and the diagnoses were made with cytologic and histologic criteria alone. The percentage of patients referred to the clinic with HPV found on routine Papanicolaou smears rose significantly, from 3 in 1987 to 18 in 1989. Fifteen percent of those referred because of HPV on a Papanicolaou smear were found to have cervical intraepithelial neoplasia (CIN) grade II or III after they were evaluated at the clinic. Of the 367 cases of biopsy-proven cervical HPV, only 33 (9%) were recorded on Papanicolaou smears performed immediately before the biopsy, and 140 (38%) also had concomitant, biopsy-proven CIN, grade II or III. Of the 195 instances in which the colposcopic impression was simple HPV without CIN, 46 (24%) had high-grade CIN on biopsy. We conclude that the proportion of patients with HPV-associated problems is increasing, that the Papanicolaou smear is not sensitive in detecting cervical HPV infections, that patients with HPV changes found on Papanicolaou smears should be evaluated with colposcopy and that lesions that appear colposcopically to be simple HPV should undergo biopsy to rule out the presence of high-grade CIN.


Rectal polyposis as a guide to duodenal polyposis in familial adenomatous polyposis. Almost all patients with familial adenomatous polyposis (FAP) develop duodenal polyps, the severity of which is graded stage 1 (minor) to stage V (cancer). Regular endoscopy is recommended for all patients with FAP. To test whether the development of severe duodenal polyposis could be predicted in another way, rectal and duodenal polyp severity were compared in 91 patients with FAP. The fulguration ratio (number of rectal fulgurations divided by number of years since colectomy) supplied the rectal polyp severity index. Patients with stage V duodenal polyposis had significantly higher fulguration ratios (median 0.38) than did patients with stage 1 disease (median 0; P = 0.009). However, the wide scatter of results means that rectal polyp severity cannot be used as a guide to duodenal polyp severity in individual patients. The coexistence of populations with severe duodenal and rectal polyposis suggests that environmental factors are important in phenotypic expression in FAP.


Three-dimensional structure of a mutant ribonuclease T1 (Y45W) complexed with non-cognizable ribonucleotide, 2'AMP, and its comparison with a specific complex with 2'GMP. The crystal structure of a mutant ribonuclease T1 (Y45W) complexed with a non-cognizable ribonucleotide, 2'AMP, has been determined and refined to an R-factor of 0.159 using X-ray diffraction data at 1.7 A resolution. A specific complex of the enzyme with 2'GMP was also determined and refined to an R-factor of 0.173 at 1.9 A resolution. The adenine base of 2'AMP was found at a base-binding site that is far apart from the guanine recognition site, where the guanine base of 2'GMP binds. The binding of the adenine base is mediated by a single hydrogen bond and stacking interaction of the base with the imidazole ring of His92. The mode of stacking of the adenine base with His92 is similar to the stacking of the guanine base observed in complexes of ribonuclease T1 with guanylyl-2',5'-guanosine, reported by Koepke et al., and two guanosine bases, reported by Lenz et al., and in the complex of barnase with d(GpC), reported by Baudet & Janin. These observations suggest that the site is non-specific for base binding. The phosphate group of 2'AMP is tightly locked at the catalytic site with seven hydrogen bonds to the enzyme in a similar manner to that of 2'GMP. In addition, two hydrogen bonds are formed between the sugar moiety of 2'AMP and the enzyme. The 2'AMP molecule adopts the anti conformation of the glycosidic bond and C-3'-exo sugar pucker, whereas 2'GMP is in the syn conformation with C-3'-endo-C'-2'-exo pucker. The mutation enhances the binding of 2'GMP with conformational changes of the sugar ring and displacement of the phosphate group towards the interior of the catalytic site from the corresponding position in the wild-type enzyme complex. Comparison of two crystal structures obtained provides a solution to the problem that non-cognizable nucleotides exhibit unexpectedly strong binding to the enzyme, compared with high specificity in nucleolytic activity. The results indicate that the discrimination of the guanine base from the other nucleotide bases at the guanine recognition site is more effective than that estimated from nucleotide-binding experiments so far.


Structural details of ribonuclease H from Escherichia coli as refined to an atomic resolution. The crystal structure of RNase H from Escherichia coli has been determined by the multiple isomorphous replacement method, and refined by the stereochemically restrained least-squares procedure to a crystallographic R-factor of 0.196 at 1.48 A resolution. In the final structure, the root-mean-square (r.m.s.) deviation for bond lengths is 0.017 A, and for angle distances 0.036 A. The structure is composed of a five-stranded beta-sheet and five alpha-helices, and reveals the details of hydrogen bonding, electrostatic and hydrophobic interactions between intra- and intermolecular residues. The refined structure allows an explanation of the particular interactions between the basic protrusion, consisting of helix alpha III and the following loop, and the remaining major domain. The beta-sheet, alpha II, alpha III and alpha IV form a central hydrophobic cleft that contains all six tryptophan residues, and presumably serves to fix the orientation of the basic protrusion. Two parallel adjacent helices, alpha I and alpha IV, are associated with a few triads of hydrophobic interactions, including many leucine residues, that are similar to the repeated leucine motif. The well-defined electron density map allows detailed discussion of amino acid residues likely to be involved in binding a DNA/RNA hybrid, and construction of a putative model of the enzyme complexed with a DNA/RNA hybrid oligomer. In this model, a protein region, from the Mg(2+)-binding site to the basic protrusion, covers roughly two turns of a DNA/RNA hybrid double helix. A segment (11-23) containing six glycine residues forms a long loop between the beta A and beta B strands. This loop, which protrudes into the solvent region, lies on the interface between the enzyme and a DNA/RNA hybrid in the model of the complex. The mean temperature factors of main-chain atoms show remarkably high values in helix alpha III that constitutes the basic protrusion, suggesting some correlation between its flexibility and the nucleic acid binding function. The Mg(2+)-binding site, surrounded by four invariant acidic residues, can now be described more precisely in conjunction with the catalytic activity. The arrangement of molecules within the crystal appears to be dominated by the cancelling out of a remarkably biased charge distribution on the molecular surface, which is derived in particular from the separation between the acidic Mg(2+)-binding site and the basic protrusion.


Thermodynamic characterization of cytochrome c at low pH. Observation of the molten globule state and of the cold denaturation process. Several reports have pointed out the existence of intermediate states (both kinetic and equilibrium intermediate) between the native and the denatured states. The molten globule state, a compact intermediate state in which the secondary structure is formed but the tertiary structure fluctuates considerably, is currently being studied intensively because of its possible implication in the folding process of several proteins. We have examined the thermal stability of horse cytochrome c at low pH between 2.0 and 3.2 and different potassium chloride concentrations by absorbance of the Soret band, far and near-ultraviolet circular dichroism (u.v. c.d.) and tryptophan fluorescence using a multidimensional spectrophotometer. The concentration of potassium chloride ranged from 0 M to 0.5 M. The experimental thermal denaturation curves show that: (1) the helical content of cytochrome c remains stable at higher temperature when the concentration of salt is increased; whereas (2) the extent of ordering of the tertiary structure is weakly dependent on salt concentration; and (3) for cytochrome c, the stabilization of the molten globule state is induced by the binding of anions. Other salts such as NaCl, LiCl, potassium ferricyanide (K3Fe(CN)6) and Na2SO4 may also be used to stabilize the molten globule state. The thermodynamic analysis of the denaturation curves of c.d. at 222 nm and c.d. at 282 nm shows that, whereas a two-state (native and denatured) transition is observed at low-salt concentration, the far and near-u.v. c.d. melting curves of cytochrome c do not coincide with each other at high-salt concentration, and a minimum of three different thermodynamic states (IIb, intermediate or IIc, and denatured) is necessary to achieve a sufficient analysis. The intermediate state (called IIc) is attributed to the molten globule state because of its high secondary structure content and the absence of tertiary structure. Therefore, at low pH, cytochrome c is present in at least four states (native, IIb, IIc and denatured) depending on the salt concentration and temperature. The thermodynamic parameters, i.e. the Gibbs free energy differences (delta G), the enthalpy differences (delta H), the midpoint temperatures (Tm) of the transition (IIb in equilibrium intermediate (IIc in equilibrium denatured) are determined. We also give estimates of the heat capacity differences (delta Cp) from the temperature dependence of the enthalpy differences. The enthalpy change and the heat capacity difference of the IIc in equilibrium denatured transition are non-zero. The number of charges (protons or chloride anions) released upon transitions are determined by analysing the pH and chloride anion concentration dependence of the Gibbs free energy.(ABSTRACT TRUNCATED AT 400 WORDS)


Crystallization and preliminary X-ray diffraction studies of coxsackievirus B1. Preparations of coxsackievirus B1 (CVB1) derived from an infectious cDNA clone have been crystallized in multiple crystal forms. Using high intensity synchrotron radiation, an orthorhombic form of the crystals was shown to diffract X-rays to at least 2.9 A resolution. The unit cell has a primitive lattice with dimensions a = 323 A, b = 450 A, and c = 522 A. A crystallographic asymmetric unit of these CVB1 crystals probably contains an entire virus particle, implying the presence of 60-fold non-crystallographic redundancy. This CVB1 crystal form appears to be suitable for high-resolution structure determination by X-ray crystallography.


Crystallization and preliminary X-ray investigation of a ubiquitin carrier protein (E2) from Arabidopsis thaliana. Crystals of a recombinant ubiquitin carrier protein from Arabidopsis thaliana have been grown from solutions of ammonium sulfate. The crystals are orthorhombic, space group P2(1)2(1)2(1); the axes are a = 41.8(1) A, b = 44.9(1) A and c = 83.2(1) A. The crystals are quite stable to X-rays and diffract beyond 2.1 A resolution. There is one molecule in the asymmetric unit.


Two independent amsacrine-resistant human myeloid leukemia cell lines share an identical point mutation in the 170 kDa form of human topoisomerase II. Cloning and sequencing of cDNA segments of human TOP2 gene encoding the 170 kDa form of human DNA topoisomerase II show that Arg486 of the enzyme has been mutated to a lysine in the enzyme from two human leukemia cell lines HL-60/AMSA and KBM-3/AMSA, which were independently selected for resistance to the antitumor drug amsacrine (4'-[9-acridinylamino]-methanesulfon-m-anisidide, mAMSA). Sequence identity comparisons between eukaryotic DNA topoisomerase II and bacterial gyrase (bacterial DNA topoisomerase II) indicate that the position of the common mutation observed in mAMSA-resistant human TOP2 corresponds to that of the point mutation nal-31 in the Escherichia coli gyrase B gene, which confers resistance to nalidixic acid. Because mAMSA and nalidixic acid are known to act on their respective targets by a common mechanism of trapping the covalent enzyme-DNA intermediates, these results provide strong evidence that the 170 kDa form of human DNA topoisomerase II is a major cellular target of mAMSA, and that Arg486 of this enzyme is involved in mAMSA-mediated trapping of the covalent enzyme-DNA complex.


Oxidation state-dependent conformational changes in cytochrome c. High-resolution three-dimensional structural analyses of yeast iso-1-cytochrome c have now been completed in both oxidation states using isomorphous crystalline material and similar structure determination methodologies. This approach has allowed a comprehensive comparison to be made between these structures and the elucidation of the subtle conformational changes occurring between oxidation states. The structure solution of reduced yeast iso-1-cytochrome c has been published and the determination of the oxidized protein and a comparison of these structures are reported herein. Our data show that oxidation state-dependent changes are expressed for the most part in terms of adjustments to heme structure, movement of internally bound water molecules and segmental thermal parameter changes along the polypeptide chain, rather than as explicit polypeptide chain positional shifts, which are found to be minimal. This result is emphasized by the retention of all main-chain to main-chain hydrogen bond interactions in both oxidation states. Observed thermal factor changes primarily affect four segments of polypeptide chain. Residues 37-39 show less mobility in the oxidized state, with Arg38 and its side-chain being most affected. In contrast, residues 47-59, 65-72 and 81-85 have significantly higher thermal factors, with maximal increases being observed for Asn52, Tyr67 and Phe82. The side-chains of two of these residues are hydrogen bonded to the internally bound water molecule, Wat166, which shows a large 1.7 A displacement towards the positively charged heme iron atom in the oxidized protein. Further analyses suggest that Wat166 is a major factor in stabilizing both oxidation states of the heme through differential orientation of dipole moment, shift in distance to the heme iron atom and alterations in the surrounding hydrogen bonding network. It also seems likely that Wat166 movement leads to the disruption of the hydrogen bond from the side-chain of Tyr67 to the Met80 heme ligand, thereby further stabilizing the positively charged heme iron atom in oxidized cytochrome c. In total, there appear to be three regions about which oxidation state-dependent structural changes are focussed. These include the pyrrole ring A propionate group, Wat166 and the Met80 heme ligand. All three of these foci are linked together by a network of intermediary interactions and are localized to the Met80 ligand side of the heme group. Associated with each is a corresponding nearby segment of polypeptide chain having a substantially higher mobility in the oxidized protein.(ABSTRACT TRUNCATED AT 400 WORDS)


Melanotic neuroectodermal tumor of infancy: an important mimicker of paratesticular rhabdomyosarcoma. We report a case of a paratesticular tumor in a 6-month-old infant. This tumor was originally believed to represent a poorly differentiated sarcoma of the cord but upon further pathological consultation it was recognized as a rare melanotic neuroectodermal tumor of infancy involving the epididymis. Since the former is a highly aggressive lesion and the latter an indolent tumor, treatment of these 2 entities differs markedly. Therefore, although the histological distinction between these lesions is often difficult, it is of critical importance.


Adenoid cystic carcinoma of Cowper's gland. We report an additional case of primary adenoid cystic carcinoma of Cowper's gland in an otherwise healthy asymptomatic 66-year-old man. Based on a review of similar lesions presenting in the head and neck, our treatment plan entailed pelvic exenteration followed by radiation therapy. Whether adenoid cystic carcinoma of Cowper's gland behaves as aggressively as it does in the head and neck remains unclear. However, in view of the extensive local invasion in our patient and a previously successful outcome, a combined surgical and radiation approach appears to be the most appropriate therapy.


Small cell anaplastic carcinoma of the prostate: a clinical, pathological and immunohistological study of 27 patients. Because small cell anaplastic carcinoma of the prostate is an uncommon tumor, it has remained a poorly defined entity. To elucidate further the clinical, pathological and immunohistochemical characteristics of this cancer the 27 patients who presented to the Mayo Clinic from 1960 to 1990 were reviewed. Of these patients 18 (67%) presented with pure small cell anaplastic carcinoma, and 9 (33%) were diagnosed with small cell anaplastic carcinoma and adenocarcinoma of the prostate. Twenty-six patients (96%) had either stage C or D disease at the time of diagnosis. Two patients presented with a paraneoplastic syndrome, including 1 man with inappropriate antidiuretic hormone secretion and 1 who suffered from thyroxine intoxication. Of 24 men with long-term followup 22 (92%) died of small cell anaplastic carcinoma of the prostate despite antiandrogen therapy and the remaining 2 are alive with active, progressive disease. The median survival time following diagnosis was 17.1 months (range 2 to 90 months). All tumors with tissue available for immunohistochemical staining reacted positive for neuron-specific enolase, indicating that small cell anaplastic carcinoma of the prostate is most likely a neuroendocrine neoplasm. No tumor stained positive for either prostatic acid phosphatase or prostate specific antigen. Pathologically, small cell anaplastic carcinoma of the prostate appears to be similar to oat cell carcinoma of the lung. This series of 27 patients emphasizes that small cell anaplastic carcinoma of the prostate is highly malignant, is frequently of advanced stage at presentation, responds poorly to antiandrogen therapy and has a poor prognosis.


Chemotherapy for small cell carcinoma of prostatic origin. A total of 21 patients with metastatic small cell carcinoma of the prostate was treated with combination chemotherapy, either following initial hormonal therapy (15) or as initial therapy (6). Of the patients 13 (62%) had pure small cell carcinoma, whereas 8 (38%) had mixed histology of small cell carcinoma and adenocarcinoma. Patients presented with a characteristic clinical picture of a large primary mass (16 cases) with a high frequency of visceral metastases to the liver (9), lungs (7) and brain (2). The majority of the patients did not have an elevated serum prostate specific antigen (1 of 14, 7%) or prostatic acid phosphatase (2 of 21, 10%). Serum carcinoembryonic antigen was elevated in 13 patients (62%). Of the 21 patients 13 (62%) responded to chemotherapy. Survival after the diagnosis of small cell carcinoma of the prostate resulted in a median of 9.4 months with a range of 1 to 25 months. The regimens used were those considered active in the treatment of small cell carcinoma of the lung (vincristine, doxorubicin and cyclophosphamide, or etoposide and cisplatin with or without doxorubicin). Small cell carcinoma of the prostate has a characteristic clinical picture and a high response rate to cytotoxic therapy. Early introduction of chemotherapy in the treatment of small cell carcinoma of the prostate may increase the survival rate.


Development of spongiform encephalopathy in retroviral infected mice. The Cas-Br-E strain of murine leukemia virus is a neurovirulent retrovirus that induces progressive noninflammatory degeneration of the central nervous system (CNS). The molecular clone pNE-8 retains pathogenic properties of Cas-Br-E. The neurotropic determinants are known; however, the mechanism of neuropathogenesis is unknown. We examined the temporal development of disease after infection of SWR/J mice with pNE-8 virus. Development of CNS lesions, cellular targets of viral replication, accumulation of ubiquitinated proteins and integrity of blood-brain barrier were determined in mice infected with pNE-8 virus; and compared with uninfected, sham-infected, and nonneuropathogenic virus-infected mice. During 24 weeks of pNE-8 infection, noninflammatory spongiform lesions developed initially in the lumbar spinal cord and progressed to involve the brainstem and deep cerebellar nuclei. Virions and viral antigens accumulated for 18 weeks postinfection and then declined. Major sites of viral infection outside the CNS were splenic megakaryocytes, and skeletal muscle. Cellular targets of viral replication in the CNS included neurons, oligodendrocytes, and capillary endothelium. No astrocytic infection was observed; however, a reactive gliosis marked the development of clinical symptoms and histopathology. Spongiform lesions began as swelling of perivascular astrocytic processes. Intramyelinic vacuoles with splitting of myelin at major dense lines were prominent around dystrophic axons at later time points. Dendritic processes showed vacuolization and local degeneration. Viral particles were most commonly observed in extracellular spaces and within rough endoplasmic reticulum of neurons, oligodendrocytes, and splenic megakaryocytes. Infected megakaryocytes and regions of spleen containing viral aggregates showed accumulation of ubiquitinated proteins. Areas of histopathology in the CNS showed accumulation of ubiquitinated proteins but unlike spleen, viral proteins were not highly ubiquitinated. Disruption of the blood brain barrier was only evident at late stages of infection. In conclusion, the neuropathogenic damage associated with pNE-8 infection appears to be tightly associated with direct viral infection of oligodendroglia and neurons.


Expression of surfactant associated protein-A and Clara cell 10 kilodalton mRNA in neoplastic and non-neoplastic human lung tissue as detected by in situ hybridization. Two markers for the progenitor cells of peripheral airways and their tumors are the 10 kilodalton (kd) Clara cell protein and the major surfactant associated protein-A (SP-A). We used the RNA-RNA in situ hybridization technique to study expression of the genes encoding these proteins at the cellular level in 19 pairs of non-neoplastic and neoplastic tissues from resected human lungs. Our results show that in non-neoplastic lung tissue, the Clara 10 kd protein gene was expressed in nonciliated cells of both bronchial and bronchiolar epithelium, indicating that, in contrast to previous assumptions, cells with Clara cell-like differentiation in humans may not be restricted to bronchiolar cells. The incidence of Clara 10 kd protein gene expression, as detected in lung carcinomas (1 out of 19 cases positive) was less than expected based on previous ultrastructural reports. The SP-A gene was strongly expressed in normal alveolar type II cells in non-neoplastic lung and, at higher levels, in hyperplastic cells. In addition, SP-A mRNA expression was observed in scattered bronchial and bronchiolar epithelial cells in 40% of the airways examined. Five out of 17 lung tumors, all of which were adenocarcinomas, were positive for SP-A expression, albeit generally less intense than type II cells. This expression was seen in carcinomas with papillolepidic as well as solid and glandular growth patterns. Our findings provide new insights into the peripheral airway cell differentiation.


Ductal carcinoma in situ in rat mammary gland. Antiestrogen therapy has been proposed as a treatment option for ductal carcinoma in situ (DCIS). However, its effectiveness has not been evaluated in the laboratory due to lack of an animal model. The present study was undertaken to evaluate the incidence, time span, and number of mammary glands involved with DCIS in a rat model treated with N-nitroso-N-methylurea (NMU). Sprague Dawley female rats 44 to 49 days old were treated with two iv doses of 5 mg NMU/100 g body wt given 7 days apart, initiated at diestrus. Animals were killed at intervals beginning 21 days following first injection. Breast tissues were evaluated following routine H&E stain. Standard histologic criteria were followed to establish the diagnosis of DCIS. The number of glands involved with DCIS increased from one to seven with time from first injection. This model demonstrates an incidence of 87% for DCIS and 0% for invasive Ca between 22 and 45 days following NMU injection. Nine rats were sacrificed between 50 to 60 days and five showed invasive carcinoma. This model appears suitable for studying the efficacy of hormone or chemoprevention in the progression of DCIS to invasive Ca.


The distal axis of growth hormone (GH) in nutritional disorders: GH-binding protein, insulin-like growth factor-I (IGF-I), and IGF-I receptors in obesity and anorexia nervosa. The endocrine abnormalities along the growth hormone (GH) axis in anorexia nervosa (AN) and in obesity include hypothalamic, pituitary, and peripheral elements. The present study was undertaken to evaluate the effects of these nutritional extremes on GH-binding protein (BP) levels and on Insulin-like growth factor-I (IGF-I) receptors on red blood cells (RBC). Nine patients with AN and 20 obese subjects were compared with normal control children, adolescents, and adults. GH-BP was measured by a binding assay with dextran-coated charcoal separation. IGF-I binding was measured on enriched RBC. Serum GH-BP levels were markedly reduced in the AN patients, and highly increased in the obese. Scatchard analyses showed linear plots with unaltered binding affinities (Ka). The binding capacity (Bmax) was significantly lower than normal control in the AN patients and higher in the obese. GH-BP levels correlated positively with the body mass index (BMI). RBC [125I]IGF-I binding was significantly elevated in the AN patients and low in the obese. Scatchard analyses showed curvilinear plots. The high-affinity constants (Ka1) were slightly, but significantly, higher in the AN patients and in the obese compared with control. The binding capacity of the first binder (Bmax1) was lower in obesity than in AN or control. The low-affinity constants (Ka2) were similar in the three groups, and its binding capacity (Bmax2) was similar in the AN patients and the controls, but significantly lower in the obese. [125I]IGF-I binding correlated negatively and significantly with the BMI and with the GH-BP.(ABSTRACT TRUNCATED AT 250 WORDS)


Serotoninergic receptor activation by dextrofenfluramine enhances the blunted pituitary-adrenal responsiveness to corticotropin-releasing hormone in obese subjects. To explore the interrelationships between the serotoninergic system and the hypothalamic-pituitary-adrenal (HPA) axis in human obesity, we evaluated cortisol and adrenocorticotropic hormone (ACTH) response to synthetic human corticotropin-releasing hormone (hCRH, 1 microgram/kg intravenously [IV]) before and after stimulation of the serotoninergic system by dextrofenfluramine (d-FF, 30 mg/d for 3 months) in nine obese women. These responses were compared with a CRH test (1 microgram/kg) carried out in nine age-matched normal-weight women. Plasma cortisol of obese subjects did not significantly increase after CRH (peak value 127.1 +/- 11.2 ng/mL v 104.1 +/- 9.5 ng/mL). This response was lower (P less than .005) than in the controls, in whom the basal cortisol value of 120.6 +/- 11.8 ng/mL reached a peak value of 221.2 +/- 13.4 ng/mL. However, after administration of d-FF, CRH significantly increased (P less than .0001) plasma cortisol (peak value 170.6 +/- 18.0 ng/mL v 111.5 +/- 10.8 ng/mL) and the response was enhanced (P less than .05) as compared with that obtained before d-FF. The ACTH levels of our patients showed a small increment after CRH injection (peak value 13.5 +/- 1.7 pg/mL v 9.6 +/- 1.1 pg/mL), but the hormonal response was lower (P less than .005) than in controls (peak value 38.1 +/- 5.5 pg/mL v 13.8 +/- 0.8 pg/mL). However, after d-FF, CRH induced a significant increment (P less than .05) in plasma ACTH at 30 minutes (20.4 +/- 3.7 pg/mL v 10.9 +/- 0.9 pg/mL) and 45 minutes (18.0 +/- 2.6 pg/mL), even though this response was not significantly different from that observed before d-FF administration.(ABSTRACT TRUNCATED AT 250 WORDS)


Na+/K(+)-ATPase activity and its alpha II subunit gene expression in rat skeletal muscle: influence of diabetes, fasting, and refeeding. We have examined the effects of diabetes, fasting, and refeeding on Na+/K(+)-adenosine triphosphatase (ATPase) activity and its catalytic alpha II subunit gene expression in skeletal muscle. Two hypoinsulinemic states, streptozotocin-induced diabetes and 48-hour fasting caused a significant decrease (P less than .05) in skeletal muscle Na+/K(+)-ATPase activity and a marked increase (P less than .01) in the levels of alpha II subunit mRNA. A decrease in enzyme activity was observed on the 2nd and the 14th day of diabetes, whereas an increase in alpha II mRNA levels was found only on the 14th day. The levels of alpha I mRNA were not affected, while the levels of mRNA of the structural beta subunit were decreased on the 14th day of diabetes. Correction of hyperglycemia with insulin restored enzyme activity and alpha II isoform mRNA levels toward normal in diabetic animals. Refeeding for 48 or 72 hours restored these parameters to normal in skeletal muscle of previously fasting rats. These observations suggest that a decrease in muscle Na+/K(+)-ATPase activity may lead to a compensatory increase in its alpha II subunit gene expression. The levels of insulin and not of glycemia appear to be critical in modulating Na+/K(+)-ATPase activity and gene expression.


The structure of an integrated copy of the giant linear plasmid SCP1 in the chromosome of Streptomyces coelicolor 2612. In NF strain 2612 of Streptomyces coelicolor, a giant linear plasmid SCP1 is integrated into the chromosome at the 9 o'clock position. To characterize the integrated structure of SCP1, cloning and sequence analysis of the two junctions between the SCP1 DNA and the chromosomal DNA was carried out. The left junction was revealed to retain an almost intact left terminus of SCP1. On the other hand, the right junction was composed of IS466, deleting completely the right terminal inverted repeat of SCP1. This junction might have been formed by recombination of two IS466 elements, one present at the end of the right terminal inverted repeat of SCP1 and one on the chromosome. Based on these results, we have proposed a model for the integration of SCP1 into the chromosome. The unique conjugal transfer of NF strains and the origin of the chromosomal antibiotic biosynthetic genes in Streptomyces species are also discussed in relation to this model.


Transactivation of Ds by Ac-transposase gene fusions in tobacco. To study regulation of the (Ds) transposition process in heterologous plant species, the transposase gene of Ac was fused to several promoters that are active late during plant development. These promoters are the flower-specific chalcone synthase A promoter (CHS A), the anther-specific chalcone isomerase B promoter CHI B and the pollen-specific chalcone isomerase A2 promoter CHI A2. The modified transposase genes were introduced into a tobacco tester plant. This plant contains Ds stably inserted within the leader sequence of the hygromycin resistance (HPT II) gene. As confirmed with positive control elements, excision of Ds leads to the restoration of a functional HPT II gene and to a hygromycin resistant phenotype. No hygromycin resistance was observed in negative control experiments with Ac derivatives lacking 5' regulatory sequences. Although transactivation of Ds was observed after the introduction of transposase gene fusions in calli, excision in regenerated plants was observed only for the CHS A- or CHI B-transposase gene fusions. With these modified transposase genes, somatic excision frequencies were increased (68%) and decreased (22%), respectively, compared to the situation with the Ac element itself (38%). The shifts in transactivation frequencies were not associated with significant differences in the frequencies of germinally transmitted excision events (approximately 5%). The relative somatic stability of Ds insertions bearing the CHI B-transposase gene fusion suggests the usefulness of this activator element for transposon tagging experiments.


Topoisomerase II-mediated DNA cleavage activity and irreversibility of cleavable complex formation induced by DNA intercalator with alkylating capability. A group of chrysophanol and emodin derivatives with DNA-intercalating capability and with or without alkylating potential have been synthesized and shown to have antitumor activity in vitro. The topoisomerase II (Topo II)-mediated DNA cleavage activities induced by representative compounds 3-(2-chloroethylamino) methyl-1,8-dihydroxy-9,10-anthraquinone (SK-31690), 3-bis [(2-chloroethyl)amino]methyl-1,8-dihydroxy-9,10-anthraquinone (SK-31662), and 3-(2-hydroxyethylamino)methy-1,8-dihydroxy-9,10-anthraquinon e (SK-31694), and their cytotoxicities, have been investigated. All three compounds inhibited the kinetoplast DNA decatenation catalyzed by DNA Topo II. These compounds inhibited leukemia cell growth and stimulated, in a dose-dependent manner from 0.5 to 60 microM, the formation of Topo II-DNA cleavable complexes, when 3'-32P-labeled DNA was used. The mapping of Topo II-mediated DNA cleavage sites using HindIII-digested 3'-32P-labeled DNA showed that, at 10 microM, these compounds induced protein-linked DNA breaks that correlated with cytotoxicity, with respect to their maximal efficacy or the reciprocal concentration for the half-maximal effect. The reversibility study showed that the amounts of protein-linked DNA cleavage induced by 4'-(9-acridinylamino)methanesulfon-m-anisidide and VP-16 as well as SK-31694, which lacks alkylating potential, were markedly decreased during 30-sec exposure to 65 degrees or 0.5 M NaCl. In contrast, protein-linked DNA cleavages induced by SK-31662, which has two alkylating functionalities, and by SK-31690, which has one alkylating functionality in its structure, cannot be reversed during the 15-min exposure to 65 degrees or 0.5 M NaCl. These data suggest that Topo II is a major cellular target for cytotoxicity of these compounds. Furthermore, DNA intercalators with alkylating potential interact with Topo II-DNA cleavable complexes in an irreversible manner, with enhanced toxicity.


Incorporation of the carbocyclic analog of 2'-deoxyguanosine into the DNA of herpes simplex virus and of HEp-2 cells infected with herpes simplex virus. The carbocyclic analog of 2'-deoxyguanosine (CdG) is active against herpes simplex virus (HSV), human cytomegalovirus, and human hepatitis-B virus. In order to understand the mechanism of action of this compound against HSV, we have evaluated (a) the incorporation of [3H]CdG into viral and host DNA in HEp-2 cells infected with HSV and (b) the interaction of the 5'-triphosphate of CdG (CdG-TP) with the HSV DNA polymerase and human DNA polymerases alpha, beta, and gamma (EC 2.7.7.7). Incubation of HSV-1-infected HEp-2 cells with [3H]CdG resulted in the incorporation of CdG into both the HSV and the host cell DNA. These results indicated that CdG-TP was used as a substrate for HSV DNA polymerase and for at least one of the cellular DNA polymerases. Degradation of both viral and host DNA with micrococcal nuclease and spleen phosphodiesterase indicated that CdG was incorporated primarily into internal positions in both DNAs. The viral DNA containing CdG sedimented in neutral and alkaline sucrose gradients in the same way as did viral DNA labeled with [3H]thymidine, indicating that the HSV DNA containing CdG was similar in size to untreated HSV DNA. CdG-TP was a competitive inhibitor of the incorporation of dGTP into DNA by the HSV DNA polymerase (Ki of 0.35 microM) and the human DNA polymerase alpha (Ki of 1 microM). CdG-TP was not a potent inhibitor of either DNA polymerase beta or gamma. Using DNA-sequencing technology, CdG-TP was found to be an efficient substrate for HSV DNA polymerase. Incorporation of CdG monophosphate (CdG-MP) into the DNA by HSV DNA polymerase did not interfere with subsequent chain extension. These results suggested that the antiviral activity of CdG was due to its incorporation into the DNA and subsequent disruption of viral functions. In contrast, CdG-TP was not as good as dGTP as a substrate for DNA synthesis by DNA polymerase alpha, and incorporation of CdG-MP by DNA polymerase alpha inhibited further DNA chain elongation.


Platelet-activating factor stimulates phosphoinositide turnover in neurohybrid NCB-20 cells: involvement of pertussis toxin-sensitive guanine nucleotide-binding proteins and inhibition by protein kinase C. Platelet-activating factor (PAF) is an unusually potent phospholipid known to be produced by neuronal cells and to modulate cerebral blood flow and metabolism. In previous studies with NCB-20 cells, we reported that PAF induced a significant mobilization of intracellular free Ca2+ ([Ca2+]i), which was inhibited by PAF antagonists. The increase was the result of release from intracellular stores and influx from extracellular sources. The present study was designed to characterize further PAF receptor-mediated cellular signal-transduction mechanisms in myo-[3H]inositol-labeled cells. PAF induced a concentration-dependent increase in phosphatidylinositol (Pl) metabolism, with EC50 values of 1.96 +/- 0.62 nM and 1.12 +/- 0.50 nM for inositol trisphosphate (IP3) and inositol monophosphate (IP1) formation, respectively (four experiments). The maximal production of IP3 and IP1 induced by 50 nM PAF was 254 +/- 34% and 178 +/- 25% over the basal, respectively (four experiments). PAF-induced Pl metabolism was concentration-dependently inhibited by the PAF antagonist BN50739, with an IC50 value of 6.48 +/- 0.52 nM (four experiments). The protein kinase C (PKC) activator phorbol 12,13-dibutyrate concentration-dependently inhibited PAF-induced Pl metabolism and [Ca2+]i mobilization in NCB-20 cells, of NCB-20 cells with pertussis toxin (PTX) resulted in a concentration-dependent inhibition of PAF-induced IP3 production and intracellular Ca2+ release, with a maximal reduction of 66.9 +/- 3.5% and 63 +/- 6.1%, respectively, at 300 ng/ml PTX. PTX in the presence of [32P]NAD specifically [32P]ADP-ribosylated a 38-kDa protein in membranes prepared from NCB-20 cells. Pretreatment of the cells with PTX resulted in a concentration-dependent inhibition of subsequent 32P-labeling of the toxin substrate in the membranes and correlated with the uncoupling of PAF-induced IP3 formation. PAF (0.01-10 nM) elicited a concentration-related stimulation in guanosine 5'-O-(3-[35S]) triphosphate ([35S]GTP gamma S) binding to G alpha i(1,2) proteins, which was inhibited by the PAF antagonist BN50739. PAF at 10 nM also increased [35S]GTP gamma S binding to G alpha s and G alpha o. PAF-evoked activation of G alpha i(1,2) and G alpha o was reduced by preincubation with PTX. Our results reveal that neuronal cells possess PAF receptors linked through guanine nucleotide-binding proteins to phospholipase C and receptor-operated Ca2+ channels that are regulated by PKC. Both PTX-sensitive and -insensitive guanine nucleotide-binding proteins appear to couple the PAF receptor to activation of phospholipase C and the increase in [Ca2+]i. These results contribute to the further understanding of the mechanisms behind PAF actions on neuronal cells.


[35S]sadopine, a novel high affinity, high specific activity, L-type Ca2+ channel probe: characterization of two equipotent diastereomers with opposite allosteric properties. A novel 35S-labeled dihydropyridine (DHP), 1,4-dihydro-2,6-dimethyl-4-(2-trifluoromethylphenyl)-pyridine-3,5-dic arboxyl-3- [2-(N-tert-butoxycarbonyl-L-[35S]methionyl)-aminoethyl]-ester-5-ethyl ester, ([35S]sadopine) (800-1400 Ci/mmol), the respective (+)- and (-)-diastereomers, and unlabeled (+/- )-, (-)-, and (+)-sadopine were synthesized. [35S]Sadopine is an excellent high affinity, high specific activity radioligand to label selectively the DHP receptor of L-type Ca2+ channels in tissue sections as well as in membrane fragments. Both diastereomers bind to the DHP receptors in a saturable and reversible manner, with equal, subnanomolar, dissociation constants. Despite their similar affinities, (+)- and (-)-sadopine differ with respect to their kinetic properties [the association and dissociation rate constants are 10-fold higher for (+)-[35S]sadopine at 22 degrees] and their allosteric modulation of the phenylaklylamine or benzothiazepine binding domain. (+)-Sadopine is a negative but (-)-sadopine a positive allosteric modulator of (-)-[N-methyl-3H]LU49888 or (+)-cis-[3H] diltiazem binding at 30 degrees. Both diastereomers act as L-type Ca2+ channel blockers in cardiac and smooth muscle cells. Computer-based analysis of the electrostatic potentials of the two diastereomers and calculation of the interaction energies with a hypothetical DHP receptor model predicted not only the similar affinities of (+)- and (-)-sadopine but also their Ca2+ channel-blocking effects. The temperature-dependent allosteric differences between the diastereomers suggest that two distinct conformational states of the DHP receptor are stabilized in vitro, both corresponding to a nonconducting state of the channel. Our data indicate that access to the DHP receptor site, but not binding affinity, is a function of the opposite stereochemistry of the sadopine diastereomers. Therefore, labeled and unlabeled (+)- and (-)-sadopine will be useful probes to further characterize the molecular basis of DHP-Ca2+ channel interaction and the pharmacological and physiological significance of the different allosteric conformations of the channel induced by Ca2+ channel-active drugs.


Serotonin increases calcium current in human atrial myocytes via the newly described 5-hydroxytryptamine4 receptors. In various species, including humans, 5-hydroxytryptamine (5-HT) has been shown to exert positive chronotropic and inotropic cardiac effects through different types of receptors. The goal of the present study was to investigate the regulation by 5-HT of voltage-gated Ca2+ channels in human atrial myocytes and to characterize the receptor involved. Cardiomyocytes isolated enzymatically and mechanically were voltage-clamped using the whole-cell configuration of the patch-clamp technique. Extracellular perfusion of 5-HT increased Ca2+ current (ICa) amplitude with a EC50 (0.1 microM) similar to that observed with isoprenaline. The effects of 5-HT were blocked by the addition of protein kinase A inhibitor in the pipette. In addition, the effects of 5-HT, isoprenaline, and intracellular cAMP on ICa were not additive. These results support the hypothesis that the inotropic effect of 5-HT in human atrial myocytes is related to an increase of ICa via an elevation of intracellular cAMP levels and stimulation of cAMP-dependent protein kinase. The effects of 5-HT were not blocked by antagonists of 5-HT1 (methiothepin), 5-HT2 (ketanserin), or 5-HT3 (ICS 205-930 at a low concentration) receptors. The benzamide derivatives renzapride and zacopride and the azabicyclobenzimidazolone derivative BIMU 8 increased ICa, but less efficiently than did 5-HT or 5-methoxytryptamine. Moreover, ICS 205-930 at high concentrations (greater than 1 microM) completely antagonized the effects of 5-HT. Thus, the pharmacology of the 5-HT receptor involved in an increase of ICa in human atrial myocytes resembles that recently described for the 5-HT4 receptor. In atrial myocytes dissociated from rat, rabbit, guinea pig, or frog, 5-HT at high concentrations had no effect on Ca2+ currents, suggesting that the distribution of 5-HT4 receptors in cardiac tissues is species dependent.


A2A adenosine receptors from rat striatum and rat pheochromocytoma PC12 cells: characterization with radioligand binding and by activation of adenylate cyclase. Binding assays and assays of activation of adenylate cyclase with the agonists 5'-N-ethylcarboxyamidoadenosine (NECA) and CGS21680 have been used to compare adenosine receptors in rat pheochromocytoma PC12 cells and in rat striatum. The [3H]NECA binding showed two components, whereas [3H]CGS21680 bound to one component in both tissues. The Kd value for the high affinity site labeled with [3H]NECA in PC12 cell membranes (2.3 nM) was lower than that in striatum (6.5 nM). The [3H]CGS21680 binding site showed a Kd value of 6.7 nM and 11.3 nM in PC12 cells and striatum, respectively. In the presence of GTP the KD values of [3H]NECA and [3H]CGS21680 for the high affinity site were increased severalfold, whereas the low affinity sites for [3H]NECA were no longer detected with filtration assays. A comparison of the ability of a series of agonists and antagonists to inhibit high affinity binding of [3H]NECA to A2 receptors in PC12 cell and striatal membranes indicated that agonists had higher affinities and antagonists had lower affinities in PC12 cells, compared with affinities in striatal membranes. Analysis of activation of adenylate cyclase in PC12 cell membranes suggested that the dose-dependent stimulation by NECA involved two components, whereas CGS21680 stimulated via one component. The maximal stimulation by NECA significantly exceeded that caused by CGS21680. In intact PC12 cells, NECA caused a greater accumulation of AMP than did CGS21680, as was the case in membranes. In striatal membranes, NECA and CGS21680 showed similar maximal stimulations of adenylate cyclase. Both NECA and CGS21680 were more potent in PC12 cell membranes than in striatal membranes, in agreement with binding data. However, in contrast to binding data, antagonists were not less potent versus stimulation of adenylate cyclase by NECA or CGS21680 in PC12 cell membranes, compared with striatal membranes. In toto, the results suggest that A2A receptors in striatum are virtually identical to the A2A receptors in PC12 cells. But, in addition to an A2A receptor, it appears that a lower affinity functional receptor, probably an A2B receptor, is present in PC12 cells and PC12 cell membranes, whereas such a functional low affinity receptor is not detectable in striatal membrane.