Morpho-functional differentiation in lobular carcinoma of the breast. Lobular carcinoma of the breast has been studied using histochemical methods for mucosubstances; immunocytochemical methods for casein and actin; the ruthenium red electronycytochemical method for acid glycoproteins and an immunoelectroncytochemical method for casein. Mucosubstances and casein showed a similar cytoplasmic localization, but casein production was much more intense and also showed a more diffuse cytoplasmic localization. Occasionally casein assumed the form of target-like 'inclusions' as seen characteristically with the mucosubstances. The neoplastic cells were not stained by antisera against actin. Ultrastructurally, some cells showed an intracytoplasmic lumen with microvilli and/or an irregular outline at one extremity which was covered by microvilli. An electron-dense 'fuzz' and casein coated the microvilli of cells exposed respectively to ruthenium red and an anticasein serum followed by peroxidase--anti-peroxidase complexes. It is concluded that lobular carcinoma shows evidence of epithelial rather than myoepithelial differentiation with the emphasis on epithelial secretory cells engaged in intensive milk protein production. All 10 tumours tested for oestrogen receptors were positive in contradistinction to ductal carcinoma with a lower incidence of positivity. It appears that, in addition to distinctive histological and histochemical features, lobular carcinoma has an almost constant endocrine pattern in respect of its oestrogen receptor content.


Experience in the diagnosis of glomerulonephritis using combined light microscopical, ultrastructural and immunofluorescence techniques--an analysis of 134 cases. The contribution of electron and immunofluorescence microscopy to renal biopsy diagnosis is illustrated by the results obtained in a personal series of patients with various types of glomerulonephritis. Introductory notes on the ultrastructure of the glomerular capillary and on immunological processes are also included. Immunofluorescent staining has particular value in demonstrating IgG-containing deposits in early membranous glomerulonephritis at a stage when ordinary microscopy is inconclusive. It is capable of throwing light on the mechanism of glomerular damage in severe extracapillary proliferation and in some cases of recurrent haematuria, but is less successful in separating minimal change disease from proliferative processes. Electron microscopy reveals the precise site of immune deposits and fibrin together with basement membrane changes, the microtubular structures common in SLE, and other details. It is concluded that for the accurate diagnosis of kidney disease it is essential to supplement light microscopy by one, or preferably both these methods.


Protein-lipid interactions and the role of water. The rigidity of the three-dimensional structure of a native protein is dependent on the network of hydrogen-bonded groups which provide the scaffolding for the other interactions. The structure is stabilized by the hydrophobic interactions of the nonpolar side chains. The latter are formed by the very unfavorable entropy change that occurs in water but not in less-polar solvents. It is unlikely that any solvent other than water can produce the same folding of a polypeptide chain to form the active native structure. Water plays a unique role, since it alone is responsible for the heat capacity changes observed when nonpolar groups are transferred from an aqueous to a nonaqueous environment, as exists in the interior of a protein. The need to juxtapose like groups and to avoid making contact among unlike groups imposes severe restrictions on the binding of small or large molecules to proteins. Consequently there must be proper pairing of polarities as well as close fitting of ligands for strong binding to occur. This is clearly evident from the x-ray studies of proteins containing subunits or prosthetic groups. The thermodynamic parameters observed in the most complex protein reactions--i.e., self-assembly systems--resemble rather well those observed in micelle association reactions or even in the solution of nonpolar gases in water. This interaction--hydrophobic--can be looked upon as the controlling reaction which stabilized the organized structures of most cellular entities aside from nucleic acids--i.e., membranes and organelles.


Use of enzyme-deficient cell lines as feeder layers. Enzyme-deficient cell lines, lacking TK or HPRT and therefore unable to grow in HAT medium, may be used as feeder layers to enhance clonal growth of wild-type cells. Low numbers of wild-type test cells may be plated in HAT medium with 5 X 10(5) HAT-sensitive feeder cells per Petri dish. The feeder cells remain attached and metabolizing for 1 to 2 weeks, but ultimately die and detach, leaving colonies of test cells. This feeder layer technique is very simple and flexible and could have wide applicability.


An improved technique of preparing bone-marrow specimens for cytogenetic analysis. Sixty-six bone-marrow specimens, derived from patients with hematological and nonhematological disorders, were processed for cytogenetic analysis. Modifications of various parameters of the standard (direct) culture procedure were investigated and the quality of the preparations determined. As a result of these experiments, an improved culture technique was developed that yielded significantly better quality chromosome preparations. This method is based on a short incubation (25-min) of the bone-marrow specimen, immediately following aspiration, in a solution containing both hypotonic KCl and colcemid and completely omits the use of tissue culture medium.


Regulation of the immune response in autoimmune NZB/NZW F1 mice. II. Age dependent release of suppressive factors from spleen cells. Supressor cells in the spleens of overtly autoimmune NZB X NZW (B/W) mice, but not age matched normal strain mice, were shown to release a small, less than 20,000 Dalton factor which inhibited early events in the anti-SRBC PFC response and the mitogenic response. This splenic inhibitory factor (SIF) was (i) stable on heating (56 degrees, 30 min) and freezine (-70degrees); (ii) non-specific for antigen; (iii) absorbed and/or inactivated by target cells in young B/W spleen cell cultures and (iv) released gradually into the culture medium by metabolically active cells. SIF also blocked the T-cell replacing effect of allogeneic factor (TRF) in the anti-SRBC response. These observations suggest that SIF may lead to the immunodepressed state in overtly autoimmune B/W mice by preventing the activation or differentiation of lymphocytes responding to exogenous antigen.


Immunological studies of human placentae: identification and distribution of proteins in immature chorionic villi. Cryostat sections of normal human first-trimester placentae have been studied by indirect immunofluorescence to localize numerous protein antigens to well-defined anatomical regions. Transferrin was identified in the apical aspect of all trophoblasts. Fibrinogen/fibrin was also clearly demonstrated in speckled pattern in this location and similar reactions were also observed for alpha-2-macroglobulin, IgG and C3. Plasminogen was identifiable in trophoblasts, and beta-2-microglobulin was uniformly absent from these cells. Collagen and fibrinogen/fibrin were demonstrated on trophoblastic basement membrane, whereas IgG and C3 were only very rarely identified at this site. Few antisera gave strong staining of first-trimester villous stroma, although collagen was shown to contribute much of the stromal matrix. Fibrinogen/fibrin, plasminogen, alpha-2-macroglobulin, C4, C3, C1q, IgG and caeruloplasmin gave positive reactions in fibrin and fibrinoid areas, and phytohaemagglutinin was demonstrated to bind strongly to these areas as well as to trophoblastic basement membrane.


The immune response in NZB mice of different ages to thymus-dependent and thymus-independent phosphorylcholine antigens. This study was designed to examine aberrations of immune responses in autoimmune NZB strain mice during ageing, at the level of individual B cell clones. The response to phosphorylcholine (PC) was chosen because murine responses to PC are restricted to a few B cell clones and can be characterized with idiotypic markers. Responses to both thymus-dependent (TD) and thymus-independently (TI) PC-containing antigens were measured in mice ranging from 1 to 62 weeks of age. We found that: (1) TD responses to phosphorylcholine keyhole limpet haemocyanin (PC-KLH) decreased markedly (about 17-fold) between 28 and 62 weeks of age. TI responses to the R36a strain pneumococcus decreased only slightly during the same period. (2) The PFC responses to both antigens became markedly prolonged in mice older than 24 weeks. (3) The NZB response to either antigen is essentially monoclonal, as measured by inhibition of PFC with specific anti-idiotype serum and PC hapten. No age-related alteration in avidity or idiotype expression was observed. Our results demonstrate that no aberrant PC-reactive B cell clones appear in old NZB, and lend support to the notion that the abnormalities observed are due to defective regulatory mechanisms.


A simplified method for the in vitro induction of IgG antibody in collagen coated dishes. Culture dishes precoated with thin layers of acid soluble rat tail collagen simplify conditions necessary to obtain in vitro high IgG anti-DNP responses from primed and boosted mice. In contrast to Mishell-Dutton type cultures the use of collagen precludes the need to continually rock cultures and to add nutrients. Reduction of the cell density in collagen dishes to 10(6) cells/ml is without detriment to the antibody response. Cells adhering to collagen coated dishes after 24 h incubation provide an enriched population of IgG anti-DNP precursor cells; which will mature to antibody secretion at very low cell density (10(4) -10(5) cells/ml). However, as changes in the adhesive properties of cells to collagen occur during cell maturation, attempts to adapt the technique to obtain clones of antibody secreting cells were not wholly successful.


Cell-mediated immunological responsiveness in mice decomplemented with cobra venom factor. In vivo administration of cobra factor (CoF) the C3-activating protein of cobra venom, had no suppressive effect on the in vitro response of lymphocytes to PHA, LPS or allogeneic cells; nor did it affect the generation of cells cytotoxic to allogeneic target cells. HVG reactivity was inhibited by commercially available but not purified CoF, and the latter also failed to prolong skin allograft survival. It is concluded that in vivo complement depletion does not interfere with T cell responses, and that previous reports of prolonged survival of skin allografts and inhibition of cutaneous delayed hypersensitivity reactions following treatment with CoF may have been due to impurities in the preparations used.


The induction of salivary antibodies by topical sensitization with particulate and soluble bacterial immunogens. This investigation attempted to characterize systematically the secretory and serum immune responses following oral administration of soluble and particulate bacterial immunogens. Following oral sensitization of axenic mice with Escherichia coli lipopolysaccharide, Candidin, or streptococcal group H antigen, a substantially longer latent period was observed before all salivary samples exhibited specific agglutinins when compared to a similar immunization regimen with intact nonviable micro-organisms. Also, the peak titres of salivary agglutinins were significantly lower when the soluble antigenic counterparts of particulate E. coli or Candida albicans were utilized as immunogens. Examination of serum antibodies showed that following administration of E. coli LPS, similar titres of exocrine and serum agglutinins were noted. The serum titres were significantly greater (P less than 0.01) than those elicited by oral immunization with particulate E. coli. After termination of the topical immunization regimen, salivary agglutinins were found to decline rapidly whether immunization was via soluble or particulate antigens; however, immunization with particulate bacterial antigens appeared capable of stimulating and maintaining a higher rate of local antibody secretion than similar sensitization with soluble immunogen preparations.


Antibody induced elimination of the plasmid controlled K88 adhesion factor from a porcine enteropathogen. The heat labile K88 antigen which is a product of an episomal gene, was eliminated from a pocrine enteropathogen by passage through media containing sow colostrum antibodies raised against heart stable antigens of E. coli. In consequence the porcine enteropathogen lost its ability to adhere to and aggluinate chicken erythrocytes, and model system for piglet intestinal adhesion and virulence.


Casein-induced experimental amyloidosis. IX. Alterations in marrow dependent function. CBA/J mice receiving multiple injections of sodium caseinate (CAS) or bovine serum albumin (BSA) were assayed for marrow dependent functions by measuring their ability (i) to reject bone marrow allografts and (ii) to resist Friend virus (FV)-induced suppression of lymphocyte mitogenesis. Mice that developed amyloidosis following 25-30 injections completely lost the ability to reject allogeneic marrow cells, whereas nonamyloid BSA-treated mice had enhanced rejection of marrow allografts. There was increased resistance to the suppressive effects of FV in spleen cells from 'preamyloid' mice receiving CAS injections and nonamyloid mice receiving 10-40 BSA injections. Amyloid mice appeared to be as susceptible to the effects of FV-induced suppression as control (untreated) animals. These data indicate that alterations in marrow dependent function may be related to the pathogenesis of amyloid disease.


Direct blockade of antigen-reactive B lymphocytes by immune complexes. An 'off' signal for precursors of IgM-producing cells provided by the linkage of antigen-and Fc-receptors. Antigen-antibody complexes efficiently inhibit the induction of antibody formation. Using Mishell-Dutton cultures, it can be demonstrated that neither T cells nor their products are required for this inhibition of IgM PFC formation. The blockade is at the level of B cells and cannot be overcome by LPS or TRF. The data demonstrate that cross-linking of antigen- and Fc-receptors by antigen-antibody complexes is a blocking signal for B cells.


IgE in experimental schistosomiasis. II. Quantitative determination of specific IgE antibodies against S. mansoni: a follow-up study of two strains of infected rats. Correlation with protective immunity. Parasite specific IgE antibodies in rats infected with Schistosoma manoni were measured by passive cutaneous anaphylaxis (PCA) reactions and by the technique of immuno-adsorption. Two strains, one a low IgE producer (Fischer rats) and the other a high IgE producer (Hooded-Lister rats) were studied. In Fischer rats, a time course study of the occurrence of IgE antibodies and resistance to reinfection was made. Parasite specific IgE levels measured by immuno-adsorpiton were much lower than total IgE levels and a similar percentage of specific IgE (about 8%) was in the two strains.IgE antibodies were maximum at day 30 and day 60 after infection; however, a third peak at day 90 was observed only in Fischer rats. Some discrepancies between results obtained by PCA and immunosorbent techniques have been observed, which could be explained by differences in the affinity of IgE antibodies during infection or by the presence of total IgE in the PCA assay. There was a close parallelism between specific IgE antibodies levels and the course of immunity in Fischer rats. This parallelism supports the view that IgE could play a pre-eminent role in protective immunity in rat schistosomiasis.


Serotyping in epidemiological tracing of nosocomially acquired Proteus mirabilis in a geriatric ward. Samples taken from patients, staff, and hospital milieu at intervals of two weeks for 41 weeks were analysed for nosocomial spread of Proteus mirabilis. Eighty-eight per cent of 3,519 colonies were serotyped into 21 0 groups. By O grouping and H typing, nosocomial spread of P. mirabilis could be demonstrated in several cases between patients in the same room. No spread between rooms was found. The acquisition of P. mirabilis between patients probably occurred as the result of cross-infection due to inadequate nursing technique.


Enterotoxin-producing bacteria stools from Swedish United Nations soldiers in Cyprus. A study was designed to establish the role of heat-labile enterotoxin producing Escherichia coli and other intestinal pathogens in diarrhoeal disease in Swedish soldiers of the United Nations' Force in Cyprus. Before leaving Sweden for Cyprus, no enteropathogens were isolated from the soldiers. The study was performed from October 1975 through January 1976 and in August 1976. Enterotoxigenic strains of E. coli, Citrobacter freundii, Enterobacter cloacae and Klebsiella pneumoniae were the intestinal pathogens most frequently isolated from the cases of diarrhoea. Such strains were found in 14 of 79 diarrhoeal cases (18%) but also in 6 of 66 (9%) of next-bed-fellow controls and in 7 of 139 (5%) of healthy Cypriotic civilians. Few other pathogens were identified in the soldiers, but 9 of 139 (6%) of the Cypriots were carriers of cysts of Giardia lamblia. The results indicate that enterotoxigenic bacteria were probably the most important cause of diarrhoea of those agents identified among the Swedish UN soldiers on Cyprus. Several soldiers were colonized with these strains without contracting diarrhoea.


Indications, interpretation and applications of antibiotic assays. Routine monitoring of serum levels is imperative when antibiotics are given to patients with impairment of renal function. Other desirable indications include: need for assessment of adequate aminoglycoside levels in the initial management of severe infection; chloramphenicol therapy; need for control of bioavailability of new drugs or of new derivatives of known compounds; specific clinical situations (unexplained therapeutic failure, assessment of the oral use of antibiotics as an adequate therapy in patient with severe infections; appraisal of the innocuity of topical antibiotics in burned patients or in patients with liver or renal insufficiency). The serum antibacterial test is highly recommended for assessing the adequency of antibiotic therapy in patients with bacterial endocarditis and in infected patients with impaired host resistance such as those with leukopenia. Control of initial treatment in any severe infection, osteomyelitis (particularly when combined antibiotics are used) and tuberculosis are other indications of this test. Any attempt to correlate the results yielded by antibiotic assays with in-vivo effectiveness must take into account the patient himself and the several unknown factors which, in each individual case, can affect the ultimate result of the antibiotic therapy, such as antibiotic delivery to tissues, drug binding to cellular debris, intracellular penetration of the antibiotic, etc.


Perspective and trends for biomaterials. Biomaterials may be synthetic or of natural origin used in contact with living tissue and biological fluids for prosthetic, diagnostic, therapeutic, and storage applications. The opposing phenomena of clotting and fibrinolysis under physiological conditions significantly influence the biocompatibility of materials. Although smooth-surfaced biomaterials adsorb proteins when in contact with blood, subsequent enzymatic and hemorheological events alter these proteins, thus influencing their biological performance. In contrast to synthetic materials, the healthy, living endothelium exhibits active secretory functions in the maintenance of blood compatibility. The increasingly wide use of biomaterials besides cardiovascular surgery justifies a broad-based approach because too narrow objectives often bypass significant opportunities that are realistic in terms of technological advancement and societal needs.


Autonomic function in hemodialyzed patients. The authors have studied the autonomic function in a group of 34 regular hemodialyzed patients and in a group of 24 normal volunteers with simple, non-invasive and repeteable techniques. To evaluate autonomic function Valsalva manoeuvre, cold pressor test, mental stress test, tilt test, diving reflex test, systolic-time intervals and plasma catecholamines levels were used in all subjects. Uremic patients on maintenance hemodialysis were studied the day after hemodialysis. The response to cold pressor test, mental stress test, tilt test and plasma catecholamines levels resulted normal in all uremic patients, even if 17 out of 34 patients showed an abnormal response to the Valsalva manoeuvre (Valsalva ratio lesser than 1.40). In these patients an alteration of diving reflex and/or a pathological systolic-time interval was found. The authors suggest that sympathetic function is normal in regular hemodialyzed patients and that the abnormal response to the Valsalva manoeuvre is probably due to a defect in the vagal control of the heart and/or an alteration of cardiac performance.


Ex-vivo removal of mammalian immunoglobulin G: method and immunological alterations. We have described a clinically feasible method capable of rapidly and repeatedly removing mammalian IgG extracorporeally by adsorption onto heat-killed, formalin-stabilized Staphylococcus aureus Cowan-I. In dogs, 2-13 grams of IgG were removed in 60-70 minutes, lowering the serum concentration of IgG by 30-70 percent. Serum IgG levels returned to pre-run values within 48-72 hours and, in some cases, were higher than pre-run levels at 48-72 hours. Serum biochemical alterations were generally transient and relatively modest. Peripheral lymphocyte counts showed minimal changes but the percentage of erythrocyte rosette forming cells appeared to increase with successive runs. This method is safe and efficient, and can be repetitively performed at short intervals in dogs. This method may prove useful in diseases in which rapid removal of circulating IgG is desired.


Chromosome 14 translocations in non-Burkitt lymphomas. Chromosome studies were performed on malignant cells obtained from 27 patients with non-Burkitt lymphomas. A marker chromosome affecting the long arm of No. 14 (14q+) was the single most frequent abnormality and was noted in 17 of these patients. The frequency of the 14q+ marker varied with the type of lymphoma. For patients with malignant lymphoma, histiocytic, the frequency was 5 of 8; for mixed-cell type, 1 of 3; for poorly differentiated lymphocytic, 8 of 8; for well-differentiated lymphocytic, 0 of 3; for lymphoblastic, 0 of 1; for Hodgkin's disease, 2 of 3; and for mycosis fungoides, 1 of 1. The donor chromosome involved in the 14q translocation was identified in 12 cases; certain chromosomes appeared to be affected more frequently than others. Although the break point was band 14q32 in most cases, the exact location of the receptor site on 14q was not always consistent. The distal part of 14q24 was also involved as a receptor site in at least one translocation. These findings suggest that, in some types of lymphoid malignancy, cells with a 14q translocation have a proliferative advantage over cells with other chromosome rearrangments. The presence of the 14q translocation may be important in the future for the distinction among morphologically different, but functionally comparable, subgroups of lymphoid malignancies.


The U.S. health insurance industry: an alternative view. The health insurance industry in the U.S. can be characterized as a concentrated industry. It has evolved into its current structure as a result of certain historical conditions, particularly those following the Great Depression. The structure of the industry has had an effect on the manner in which the industry functions and the cost increases in the health care sector. Specifically, the pricing mechanism is that of a price leader setting a limit price; health premium prices are higher than would be expected under a competitive structure. Regulation has been ineffective, because it has been dominated historically by health care providers and insurers. The costs of health care in general, and hospital care in particular, have increased beyond what would be expected as a result of "cost-pass-through."


Study of a growth factor for Mycobacterium lepraemurium. I. Minimal medium. A growth promoting factor is contained in the petroleum ether or acetone extracted residue of lyophilized dry egg yolk. Egg white, horse serum, soybean powder, bovine serum albumin, egg albumin and milk were used in M. lepraemurium culture attempts as protein sources instead of yolk lipoprotein. None of these substances promoted the growth of M. lepraemurium. One percent egg white medium was prepared from the mixture of one part 1% Ogawa basal medium to two parts egg white, adjusted to pH 6.1. This medium does not permit the growth of M. lepraemurium but permits bacillary survival for two months. This medium is most suitable as a minimal medium to investigate growth factors of M. lepraemurium. Utilizing the minimal medium, the following substances were tested for growth promoting activity: lecithin, cholesterol, petroleum ether extracted fraction of yolk, butanol extracted fraction of yolk, retinol, hemin, yeast extract, broth, farnesol and dolichol fraction of chicken liver. None of these supported growth of M. lepraemurium. The following neutralizing agents of free radicals were tried in the minimal medium: triethylenediamine, beta-carotin, potassium iodide, potassium bromide, 2-aminoethylisothio-uranium-bromide, 2-aminoethyl-isothio-uranium-bromide-hydrobromide and cysteamine. None of these supported growth of M. lepraemurium.


Stability of individual antimycobacterial precipitation patterns during treatment for lepromatous leprosy. Sixty serum specimens obtained from 16 lepromatous patients at intervals during the first year of DDS treatment were studied in crossed immunoelectrophoresis against an M. leprae sonicate for possible variations of specificities and titers of antimycobacterial antibodies. All sera tested showed antibody activity against M. leprae, the number of precipitation lines produced varying between two and seven. In individual patients the numbers and positions of the precipitation lines remained remarkably constant throughout the period of study.


Use of pyridine for differentiating Mycobacterium leprae from other mycobacteria in direct microscopy. The loss of acid-fastness by M. leprae after two-hour pyridine extractions, reportedly a specific test for differentiating M. leprae from all other mycobacteria, was verified on different materials obtained from leprosy patients, histologic sections from a fatal post-BCG vaccination case and smears prepared from pure cultures of 32 strains of 18 different mycobacterial species. Under the conditions used, pyridine extraction led to complete loss of acid-fastness in M. leprae only in histologic sections of biopsy specimens from leprosy patients, whereas in direct smears from skin lesions containing M. leprae the number of acid-fast rods after pyridine extraction was either equal to or only slightly smaller than in control preparations. Moreover, since smears from pure cultures of M. avium, M. diernhoferi, M. fortuitum, M. scrofulaceum, M. vaccae and especially M. phlei displayed a smaller or greater number of nonacid-fast cells as well (in some instances only 10% to 20% of cells were found stained whereas control slides contained 90% to 100% acid-fast rods), loss of acid-fastness after two-hour pyridine extraction cannot be considered a property typical of M. leprae only.


Electron microscopic observations of cell division in Mycobacterium leprae by means of serial ultrathin sectioning. The division of Mycobacterium leprae in human skin was studied in the ultrathin sections at the electron microscopic level. A few dividing bacilli were observed. The division seemed to be accomplished by inward extension ob both the cell wall and the cytoplasmic membrane into the cytoplasm of the bacillary cell to form a septum. The intracellular membranous organelle (mesosome) is assumed to play a role in division.


Cholesterol, a factor which is required for growth of mycobacteria from leprous tissues. In a yeast extract, glycerol and sheep serum containing medium, slow but abundant growth of mycobacteria occurred when media were inoculated with M. leprae isolated from leprous tissues of armadillos (Dasypus novemcinctus Linn.). The lipid fraction of the serum was the essential factor for growth. Cholesterol not only replaced, but surpassed the growth promoting effect of the lipid fraction. However, growth of mycobacteria was observed only when media were enriched with serum. The relationship of the obtained strains of mycobacteria to leprosy is not yet clear. The following cholesterol medium, stabilized with lecithin, is proposed for primary cultivation of mycobacteria from leprous tissues: KH2PO4-8.2 gm, Na2HPO4-0.5 gm, yeast extract (Difco)-4 gm, and glycerol 30 gm, dissolved to make one liter basal medium in distilled water. Cholesterol (200 mg) dissolved in 4 ml warm acetone is injected with a syringe into the basal medium. The solution is autoclaved for ten minutes to evaporate the acetone. Lecithin, 200 mg dissolved in 20 ml of the basal medium is mixed to the medium cooled to room temperature. Nine milliliter aliquots are distributed into each of a series of 50 ml screw cap tubes and autoclaved for 25 minutes. One milliliter of filter sterilized sheep serum is added to each of the tubes containing 9 ml of the cholesterol-lecithin medium. Semisolid media are prepared the same way but 1.5% agar w/v is added to the cholesterol-lecithin medium before autoclaving. When cooled to 56 degrees C, 10% w/v sheep serum is mixed to the liquid. The medium is distributed into screw cap tubes and agar slants are poured and allowed to solidify in the inclined tubes at room temperature. Macrophages contain considerable amounts of cholesterol. Cholesterol is proposed as a possible growth factor for host grown M. leprae in the macrophages of the susceptible host and the same sterol as a growth factor for primary cultivation of mycobacteria from leprous tissues.


Cutaneous non-Hodgkin lymphoma: re-evaluation of histology using enzymecytochemical and immunologic studies. With biopsies from 101 cutaneous lymphoma patients, enzymecytochemical and immunologic features of the lesions were outlined. Their histo- and cytomorphology and Kiel classification were defined.


Plasma renin concentration during lithium therapy. Plasma renin concentration was determined in patients given lithium treatment. In longitudinal study plasma renin concentration was determined in nine patients before the start of lithium treatment and at intervals during 3 months of treatment. In a transversal study, 18 patients given lithium treatment for 2--20 years were compared with 11 control persons. In the longitudinal study, plasma renin concentrations did not, during lithium treatment, deviate significantly from pre-treatment values. In the transversal study, values in the lithium treated patients did not differ significantly from values in the control group. There were no correlations, in the transversal study, between serum lithium concentrations and plasma renin concentrations. Our study indicates that the plasma renin concentration remains unaffected by lithium administered in nontoxic doses.


Butaclamol in the treatment of schizophrenia. A standard-controlled clinical trial. A 16-week, standard-controlled, double-blind study was conducted to compare the efficacy of butaclamol with that of fluphenazine in the treatment of 24 newly admitted schizophrenic patients. Statistically significant improvement occurred in the entire population in the total scores of the BPRS and PAS; in the activation, anergia, thought disturbance and hostile/suspiciousness factor scores of the BPRS; and in the scores of 9 of the 12 factors of the PAS. There were no statistically significant differences between the scores of the two treatment groups on the total or factor scores of either scale during the course of the clinical trial. The most frequently occurring adverse effects in the butaclamol group were rigidity, akathisia and excitement/agitation. The most frequently occurring adverse effects in the fluphenazine group were insomnia, decreased motor activity and tremor. It is concluded that butaclamol exerts potent neuroleptic effects on schizophrenic patients.


Double-blind comparison of bromperidol and perphenazine. Within the scope of a clinical double-blind study, effects and side effects of Bromperidol and Perphenazine were compared. Forty newly-hospitalized schizophrenic patients were included in the trial. Assessments were made on days 0, 2, 5, 10, 20, and 30. Data were documented by means of the AMP system, the EPRS scale of Simpson and Angus, and a Brief Ward Behaviour Rating Scale. Laboratory tests and ECGs were performed before and after treatment. Treatment was scheduled for 30 days and dosages were established depending on effects and side effects. We found a therapeutic effective mean daily dose of 6 mg for Bromperidol and 20 mg for Perphenazine. Both substances caused autonomic and extrapyramidal side effects and, in a few patients, temproary fatigue. The employed dosage caused no strong sedation. To sum up, Bromperidol and Perphenazine can be described as highly potent and well tolerated antipsychotic drugs. We observed stronger efficacy and earlier onset of action with Bromperidol. The superior effect of Bromperidol cannot be explained by a higher dosage as compared with Perphenazine, since both substances showed a similar severity of extrapyramidal side effects, and the dosage of both substances was established individually for each patient, depending on effects and side effects.


Treatment of the alcoholic organic brain syndrome with EMD 21657. A derivative of a pyritinolmetabolite: double-blind clinical, quantitative EEG and psychometric studies. The efficacy of EMD 21657--a derivative of a pyritinolmetabolite--with regard to the improvement of the organic brain syndrome (OBS) of chronic alcoholics was investigated in a double-blind study utilizing clinical, psychometric and quantitative EEG evaluation. Nineteen patients received 3 x 300 mg EMD and 21 patients 3 x 1 dragee placebo for 6 weeks. The groups did not differ in regard to age, sex, weight, height, alcohol anamnesis or IQ. The hospitalized patients were examined before as well as at the end of the second, fourth and sixth week of drug treatment. While the overall evaluation by the psychiatrist and patients at the end of the period of treatment did not show marked intergroup differences, the clinical global impression scale and the OBS rating scale demonstrated that both groups showed a significant reduction in their OBS and that improvement with EMD 21657 therapy was significantly superior to the one with placebo. Psychometric analysis also exhibited a significant superiority of EMD in regard to the general, associative, numeric and total verbal memory, concentration and attention variability. Psychovisual memory and the quantative aspects of attention showed opposite findings. Flickerlight fusion frequency, reaction time and after-image did not change significantly. The psychomotor activity improved significantly more with EMD than placebo; this was especially pronounced in the left hand. Affect and mood improved also more with EMD than placebo. Side effects were observed more frequently under active treatment and were characterized by temporary headaches. Power spectral density analysis of the EEG revealed in both groups a decrease of delta, fast alpha and beta activities and an increase in theta and slow alpha activity, but changes during EMD treatment more frequently reached the level of statistical significance than with placebo. The most consistant finding was the theta augmentation under EMD treatment. It was concluded that EMD 21657 is a CNS-effective drug with pronounced nootropic and slight thymotropic properties.


Pineal gland involvement in retina-induced experimental allergic uveitis. A form of experimental allergic uveitis (EAU) can be elicited in guinea pigs by injection of an extract of homologous retina homogenate (S preparation). These guinea pigs exhibit clinical and histological ocular disease as well as cellular and humoral immune responses to S preparation. Recent studies have shown an immunofluorescent crossreactivity of the sera of these animals (anti-S) with retinal photoreceptors and pinealocytes. The experiments presented in this paper demonstrate pineal gland involvement during the course of S preparation-induced EAU. There is lymphocytic infiltration of the pineal gland, with corresponding loss of antigen reactivity and some disturbance in cell structure. Pineal gland infiltrate can be seen before observable retinal involvement. Similarity of the reactive substances in retinal photoreceptors and pinealocytes is demonstrated by a reaction of identity in immunodiffusion studies and similar mobilities in immunoelectrophoretic studies of S preparation and pineal gland extract with anti-S serum. The relationship of the retinal and pineal substances to each other, as well as their role in disease development in the animal model and possibly in human uveitides, are discussed.


Clomerulopathy in mice infected with Plasmodium berghei: induction of an autoimmune process. 1. Apparently a living, metabolizing parasite is required to induce the formation of autoantibodies. 2. It seems unlikely that immune complexes of the first type, i.e., positive for plasmodial antigens, are responsible for the induction of autoantibodies, as the transferred malarious plasma (group B) also contained that type of immune complex, but did not induce the formation of the second type of complex. 3. Although a deregulation of the immunocompetent system will occur in animals with a high parasitemia (immunosuppression), the fact that extremely low parasitemia is sufficient to induce antismoothmuscle antibodies suggests that proliferation of "forbidden clones" of self-reactive lymphocytes is not very likely. 4. Antismooth-muscle antibodies are frequently associated with active chronic hepatitis in man. Whether any damage to liver tissue (6) during malaria infection may be responsible for the induction of antismoothmuscle antibodies remains to be investigated. The clinical relevance of these findings is as yet obscure, and one should be careful in comparing these results of the rodent model with the human situation. 5. It remains to be elucidated whether the high level of so-called nonspecific antibodies in acutely infected mice can be explained entirely by the existence of antibodies to parasitic antigens and to host smooth-muscle antigens.


Comments on seroepidemiologic studies.

Comments on seroepidemiologic studies. If the tools for the control of transmission are not available, the application of seroepidemiologic methods, as an exercise in the tropics, just in order to assess the magnitude of the problem of malaria transmission, should be restricted. Application of seroepidemiologic methods in connection with control operations seems valuable. They can provide new and basic information. It is very unlikely that in control schemes, the assessment of incidence of fresh parasitemias is better, easier, or more accurate than in a serological survey. There seems to be no great interest in refining our methodology for seroepidemiologic techniques. Renewed interest will be prompted by reliable and effective control operations. This may be in the form of a vaccine, a new drug or another insecticide, but it must be within the economic limits of the malarious country.


Pituitary insufficiency following head injury. A 32-year-old man developed panhypopituitarism and diabetes insipidus shortly after sustaining a head injury. Hormonal investigation showed that basal prolactin levels were moderately elevated the first two years after the accident, but later returned to normal. There was no rise in prolactin after administration on chlorpromazine, and the response to thyrotropin-releasing hormone was attenuated. Basal luteinizing hormone and follicle-stimulating hormone levels were low and there was no change after administration of luteinizing-hormone-releasing hormone. There was also no growth hormone elevation following arginine infusion. On the other hand, there was a normal but delayed elevation of thyrotropin in response to thyrotropin-releasing hormone. Appropriate stimulation tests showed normal responsiveness of the thyroid, adrenals and testes. These findings are compatible with an injury to the pituitary stalk, damaging the neurohypophyseal tract and affecting the blood supply to the pituitary gland.


The occurrence of Clostridium botulinum and Clostridium tetani in the soil of the United States. Soil samples taken every fifty miles on four east-west transects across the United States were examined for C. botulinum and C. tetani, organisms that could inhibit the growth of C. botulinum type A, and for various soil properties. Type A strains were found mostly in the western part of the United States, in neutral to alkaline soil. Type B strains were more uniformly distributed, with a majority of them occurring east of the Mississippi River; none, however, were found in samples taken in the southermost transect. They were associated with soil of high organic content. Type C strains were found only in acid soil of the Gulf Coast, and type D strains in alkaline soil of some western states. Type E strains were mostly associated with damp to wet soil. Organisms inhibitory to type A strains were found in 4 of 21 samples of soil in which type A strains were demonstrated and in 7 of 20 samples in which they were not. Trypsin activation of culture fluids was necessary for the demonstration of most strains of types B, C, D, and E. C. tetani was demonstrated in 30 per cent of the soil samples. Its occurrence was not correlated with any particular soil type or climatic area.


Evaluation of reagin card tests for syphilis. The macroscopic rapid plasma reagin (RPR) and reagin screen (RST) card tests for syphilis were compared. Test specimens were also examined with the Venereal Disease Research Laboratory (VDRL) microscopic slide test; those reactive in the card or slide tests were examined with the fluorescent treponemal antibody-absorption (FTA-ABS) procedure. Agreement between the card tests with 2,300 specimens was 99%; among all three reagin tests it was 96.3%. With 348 specimens reactive in one or more of the tests, there was 75.6% agreement among all three tests. The FTA-ABS was reactive with 71% of the RPR- or RST- and 65% of the VDRL-reactive specimens. The comparison showed that the card tests give results in close agreement with those of VDRL while offering a number of practical advantages over it.


Evaluation of an office method of detecting bacteriuria. Although catheter-associated UTI continues to be the leading cause of nosocomial infection, epidemiological investigation of catheter use in many hospitals may be precluded by the reluctance of the laboratory to process the large number of urine cultures. We have evaluated the use by Nurse Epidemiologists of Bacturcult tubes for such purposes. The urine of 111 catheterized patients was cultured daily using both the Bacturcult and streak plate method until significant bacteriuria developed (greater than 10(5) colonies/ml). Bacturcult proved as accurate as the conventional technique in detecting bacteriuria. In contrast to previous studies, the daily incidence of infection rose with increasing duration of catheterization. Concomitant antibiotic usage reduced the risk of infection but selected out multi-drug resistant organisms. Older age and procedural errors also increased the risk of infection. The study took 150 hours to complete and cost about $250. It is concluded that Bacturcult is an accurate, simple and relatively inexpensive method of detecting bacteriuria and could be useful for investigating the epidemiology of catheter-associated infections in community hospitals.


[Posterior canal wall reconstruction--the results of a prolonged-follow-up (author's transl)]. The preservation or reconstitution of a normal external auditory canal with the obliteration of or maintenance of an aerated maistoid cavity is possible by reconstruction of the lateral attic wall and posterior canal wall. Conserved homograft cartilage and autograft cartilage or bone are considered suitable. Connective tissue and lyophilised dura are not suitable. Rejection of implants and recurrence of cholesteatoma will worsen the eventful successful outcome such that the initial success of over 90% is reduced to 75%. A longer follow-up admittedly is necessary for satisfactory assessment.


[Tympanic membrane repair with cartilage and double tissue-layered grafts (author's transl)]. This article describes the technique and advantages of a three layered repair of large perforations of the tympanic membrane using a pallisade of tragal cartilage covered by temporalis fascia and pedicled external auditory canal skin. Large defects of the tympanic membrane can be closed by this method and in addition satisfactory sound transmission can be achieved. The correct positioning of the cartilage graft complex requires training and skill, but an experienced otologist should be able to achieve this in a short time. Early or late reperforation of the graft is extremely rare and late perforations due to otitis media close spontaneously since large defects are not expected. The results in respect of graft durability and hearing improvement are very satisfactory.


[Simultaneous multiple flaps in head and neck surgery (author's transl)]. We have developed several variations of the "bilobed flap" for the reconstruction of large defects of the head and neck. In so doing, we use pedicled bi- and tri-lobed flaps, transposition-rotation skin flaps or double-rotation skin flaps. Some examples are described to illustrate the technique employed.


Effect of hyperinflation and atelectasis on fluid accumulation in the puppy lung. The effects of hyperinflation and of atelectasis on accumulation of fluid in the lung was studied in 12 anesthetized spontaneously breathing puppies. Vascular pressures were raised and the plasma colloid osmotic pressure was reduced by the infusion of 0.9% saline thus promoting the formation of pulmonary edema. A tracheostomy was performed and the left lower lobe catheterized in all puppies. In five puppies hyperinflation of the left lower lobe was achieved by applying a continuous positive airway pressure (CPAP) of 10 Torr. In seven other puppies the left lobe was made atelectatic by occluding its bronchus after ventilating the lungs with 100% oxygen. The right lung was ventilated to ambient pressure in all puppies. The extravascular lung water content was determined by the difference in wet and dry lung weights corrected for residual blood. We found that hyperinflation produced by CPAP enhanced and atelectasis opposed fluid accumulation in the puppy lung.


Effect of demycarosylturimycin on ribosomal peptidyltransferase from Escherichia coli. The effect of demycarosylturimycin H on bacterial growth, polypeptide synthesis and peptidyltransferase was studied. The effects are compared with those of intact turimycins acylated or deacylated in 4''-position of mycarose. The removal of the acyl group in 4''-position of mycarose leads to a total loss of inhibition of acceptor substrate binding while the removal of acyl mycarose moiety changes the pattern of inhibition of polypeptide synthesis.


Fecal coliform methods for examination of sea water: interlaboratory evaluation of split sample analysis. An interlaboratory study was conducted to compare the effectiveness of the following 3 multiple-tube fermentation methods for determining the most probable number (MPN) of Escherichia coli in a split artificial sea water sample: (1) the 72-hr standard methods procedure of the American Public Health Association, (2) a 24-hr elevated-temperature test using A-1 medium, and (3) a 24-hr elevated temperature test modified to include an initial 3-hr resuscitation period using A-1 medium. The capability of the laboratories to perform the 3 test procedures was also compared. Split sample replicates with low, medium, and high levels of E. coli were examined in 18 laboratories in the United States and Canada. Data indicate that the laboratories performed each test with equal capability, and all 3 procedures were equally effective in enumerating the strain of E. coli used in this investigation. By virtue of its homogeneity and stability, the split sample served as an appropriate specimen for this study and could probably be used as a proficiency test specimen for evaluating laboratory analyst performance in the bacteriological examination of sea water.


Further characterization of the R plasmid Rts1 and its mutant pTW2: replication and incompatibility of the plasmid. Incompatibility of the R plasmid Rts1 and its replication mutant pTW2 was studied in recA host cells of Escherichia coli. When the R plasmid R401, belonging to the same incompatibility group as Rts1, was used as a test plasmid, R401 was eliminated preferentially from (Rts-R401)+ cells irrespective of the direction of transfer. In contrast, pTW2 and R401 were mutually excluded. The decreased incompatibility of pTW2 was confirmed by a direct incompatibility test in which a derivative of Rts1 expelled pTW2 exclusively. Alkaline sucrose gradients of pTW2 and Rts1 DNA indicated that approximately one-fourth of the Rts1 genome was deleted in pTW2. In addition, both the various temperature-dependent properties of Rts1 and the inhibitory effect on phage T4 development were also lost in pTW2. A possible mechanism that regulates the stringent replication of Rts1 is discussed.


Cell surface growth in Escherichia coli: distribution of matrix protein. Autoradiography of cell envelope "ghosts" from Escherichia coli was used to demonstrate that newly synthesized molecules of "matrix" protein are inserted at random locations over the entire surface of the outer membrane and that, once inserted, these molecules are not thereafter conserved in any fixed spatial location.


Threonine degradation by Serratia marcescens. The wild strain of Serratia marcescens rapidly degraded threonine and formed aminoacetone in a medium containing glucose and urea. Extracts of this strain showed high threonine dehydrogenase and "biosynthetic" threonine deaminase activities, but no threonine aldolase activity. Threonine dehydrogenase-deficient strain Mu-910 was selected among mutants unable to grow on threonine as the carbon source. This strain did not form aminoacetone from threonine, but it slowly degraded threonine. Strain D-60, deficient in both threonine dehydrogenase and threonine deaminase, was derived from strain Mu-910 and barely degraded threonine. A glycine-requiring strain derived from the wild strain grew in minimal medium containing threonine as the glycine source, whereas a glycine-requiring strain derived from strain Mu-910 did not grow. This indicates that threonine dehydrogenase participates in glycine formation from threonine (via alpha-amino-beta-ketobutyrate) as well as in threonine degradation to aminoacetone.


Microcin plasmids: a group of extrachromosomal elements coding for low-molecular-weight antibiotics in Escherichia coli. Microcins are low-molecular-weight compounds produced and excreted by Enterobacteriaceae. They inhibit the growth of a wide spectrum of microorganisms. Microcin-synthesizing transconjugants were obtained in seven out of eight experiments of conjugational transfer between wild-type microcinogenic strains of Escherichia coli and E. coli strain BM21. The physical analysis of one of the transconjugant strains that has acquired the ability to produce microcin 17 showed the presence of extrachromosomal DNA as a plasmid (pRYC17) of molecular weight 36 X 10(6) (18.3-micron length), which is absent in the "microcincured" derivative strain. pRYC17 was incompatible with plasmids of the IncFII group. Other suspected plasmids containing the information for the synthesis of microcins have not been clearly classified. Strains producing microcins 93, 136, and 140 show a partial incompatibility with IncFIII group of plasmids.


Enterobacterial common antigen in mutant strains of Salmonella. A good correlation was found to exist between the serologically determined presence of enterobacterial common antigen (ECA) and the amount of the rare sugar constituent D-mannosaminuronic acid. Strains classified by serological techniques as ECA+, ECA-, and ECAtrace were found to possess the expected amounts of mannosaminuronic acid in the ECA-enriched phenol-soluble PL-L fractions. This correlation provides strong evidence on the identity of the mannosaminuronic acid-glucosamine polymer with the ECA as defined by Kunin (J. Exp. Med. 118:565-586, 1963).


Effect of near-UV light on Escherichia coli in the presence of 8-methoxypsoralen: wavelength dependency of killing, induction of prophage, and mutation. Wavelength dependency of photo-inactivation and photoinduced reverse mutation of Escherichia coli sensitized with 8-methoxypsoralen, and wavelength dependency of photoinduction of lambda prophage from the sensitized lysogen were measured in a range of 298 to 400 nm. The most efficient sensitization for these biological effects was observed between 320 and 340 nm. In the presence of 8-methyoxypsoralen, the induced mutation frequency per lethal hit was highest of 298 nm in the range examined and was gradually decreased with increasing wavelength to a minimum frequency at 345 nm. This finding may be a reflection of the production of more than one type of lesions which have different efficiencies for mutation compared with the killing efficiency.


Inducible reactivation and mutagenesis of UV-irradiated bacteriophage P22 in Salmonella typhimurium LT2 containing the plasmid pKM101. The inducible (Weigle) reactivation of UV-irradiated bacteriophage P22 has been examined on strains of Salmonella typhimurium with and without the mutagenesis-enhancing plasmid pKM101. A large inducible reactivation was observed in the plasmid-containing strain, but only a small response was observed in the strain lacking the plasmid. An increased frequency of clear-plaque mutants was detected among the survivors. The efficiencies of the plasmid-mediated and cellular repair processes have been determined. The kinetics of induction of the phage reactivation have been investigated. The relationship of the observed results to the inducible reactivation of UV-irradiated lambda in Escherichia coli and to error-prone repair is discussed.


Regulation of the synthesis of ribonucleoside diphosphate reductase in Escherichia coli: specific activity of the enzyme in relationship to perturbations of DNA replication. Ribonucleoside diphosphate reductase (RDP reductase) activity was found to greatly increase after a shift to the nonpermissive temperature in Escherichia coli mutants temperature sensitive for DNA elongation (dnaE dnaG dnaZ lig) or DNA initiation (dnaA dnaC dnaI). However, the kinetics of increase in RDP reductase after a shift to nonpermissive conditions were significantly different in initiation-defective mutants compared with elongation-defective mutants. In strains without defects in DNA metabolism, the specific activity of RDP reductase was found to increase with increasing growth rate. Nutritional shifts to faster growth conditions caused cells to transiently overproduce RDP reductase before adjusting to the new steady-state conditions.


Replication of bromodeoxyuridylate-substituted mitochondrial DNA in yeast. The DNA of several strains of Saccharomyces cerevisiae was labeled by growing the culture in medium supplemented with thymidylate and bromodeoxyuridylate. It was thus possible to follow the course of mitochondrial DNA replication in density shift experiments by determining the buoyant density distribution of unreplicated and replicated DNAs in analytical CsCl gradients. DNA replication was followed for three generations after transfer of cultures from light medium to heavy medium and heavy medium to light medium. Under both conditions, the density shifts observed for mitochondrial DNA were those expected for semiconservative, nondispersive replication. This was further confirmed by analysis of the buoyant density of alkali-denatured hybrid mitochondrial DNA. With this method, no significant recombination between replicated and unreplicated DNA was detected after three generations of growth.


Functional organization of the kdp genes of Escherichia coli K-12. The kdp genes code for a high-affinity and repressible K+ transport system. The regulation and organization of the kdp genes were analyzed by studies of constitutive mutants and of strains in which bacteriophage lambda is integrated into the kdp genes. The polar effects of lambda integration demonstrate that three of the kdp genes form an operon, kdpABC, read from A to C. The kdpD gene is a separate transcription unit and is the site of mutations making expression of the kdp genes partially constitutive. The constitutive mutants are dominant to kdpD+ in diploids. These findings, the fact that kdpD mutations identified previously are Kdp-, and the existence of intracistronic complementation between some kdpD mutations indicate that the kdpD gene product is an oligomeric positive regulator of the kdp genes. Deletions extending clockwise from kdp as far as the gltA locus were isolated from strains with bacteriophage lambda integrated into kdpD. Plaque-forming transducing lambda phages carrying the kdpABC operon were isolated.


Pathways of mutagenesis and repair in Escherichia coli exposed to low levels of simple alkylating agents. Mutagenesis by simple alkylating agents is thought to occur by either a lexA+-dependent process called error-prone repair or a lex-independent process often attributed to mispairing during replication. We show here that error-prone repair is responsible for the majority of mutants formed after a large dose of alkylating agent, but it is unlikely that it contributes significantly to mutagenesis during exposure to low concentrations of these chemicals. The mutagenicity of these low doses of alkylating agent is reduced by a repair system constitutively present in lexA+ cells but absent in lexA mutants. This system reduces mutagenesis until a second error-free system, called the adaptive responses, can be induced [P. Jeggo, M. Defais, L. Samson, and P. Schendel, Mol. Gen. Genet, 157:1-9, 1977; L. Samson and J. Cairns, Nature (London) 267:281-283, 1977]. The adaptive response is capable of dealing with a much larger amount of alkylation damage than the constitutive system and, when induced, appears to be able to reduce mutagenesis by both decreasing the number of sites available for mutagenesis and delaying the induction of error-prone repair enzymes. Finally, we discuss a model of chemically induced mutagenesis based on these findings which maintains that the observed mutation frequency is dependent on a "race" between these two error-free systems and the two mutagenic pathways.


Relationship of R6K replicating forms to the folded chromosome of Escherichia coli. An examination of the relationship of both nonreplicating and replicating forms of R6K plasmid DNA to the Escherichia coli folded chromosome showed that both forms cosediment with the chromosome in neutral sucrose gradients. Approximately 20% of the nonreplicatin molecules was found as freely sedimenting forms when the folded-configuration of the chromosomes was preserved. However, under the same conditions negligible amounts of the replicating forms were found as freely sedimenting molecules. Thus, it is concluded that the replicating forms, when compared with nonreplicating molecules, are preferentially associated with the folded chromosomal structure. Exposure of the folded chromosomal structure to RNase resulted in an unfolding of the chromosome and a concomitant increase in the amount of freely sedimenting replicating and nonreplicating forms of R6K DNA. Analyses of the single-stranded length of RNase-released nascent molecules suggest that they replicate in continuous association with the folded chromsome complex. Nonenzymatic unfolding of the chromosomes by progressively lowering the sodium ion concentration during lysis resulted in a progressive increase in the release of nonreplicating molecules. Replicating molecules wer not released by unfolding the chromosome in this fashion.


Metabolite compartmentation in Saccharomyces cerevisiae. Uninduced cultures of Saccharomyces cerevisiae exhibit high basal levels of allantoinase, allantoicase, and ureidoglycolate hydrolase, the enzymes responsible for degrading allantoin to urea. As a result, these activities increase only 4- to 8-fold upon induction, whereas the urea-degrading enzymes, urea carboxylase and allophanate hydrolase, have very low basal levels and routinely increase 30-fold on induction. Differences in the inducibility of these five enzymes were somewhat surprising because they are all part of the same pathway and have the same inducer, allophanate. Our current studies reconcile these observations. S. cerevisiae normally contained up to 1 mM allantoin sequestered in a cellular organelle, most likely the vacuole. Separation of the large amounts of allantoin and the enzymes that degrade it provide the cell with an efficient nitrogen reserve. On starvation, sequestered allantoin likely becomes accessible to these degradative enzymes. Because they are already present at high levels, the fact that their inducer is considerably removed from the input allantoin is of little consequence. This suggests that at times metabolite compartmentation may play an equal role with enzyme induction in the regulation of allantoin metabolism. Metabolism of arginine, another sequestered metabolite, must be controlled both by induction of arginase and compartmentation because arginine serves both as a reserve nitrogen source and a precursor of protein synthesis. The latter function precludes the existence of high basal levels of arginase.


Induction and inhibition of the allantoin permease in Saccharomyces cerevisiae. Allantoin uptake in Saccharomyces cerevisiae is mediated by an energy-dependent, low-Km, active transport system. However, there is at present little information concerning its regulation. In view of this, we investigated the control of alloantoin transport and found that it was regulated quite differently from the other pathway components. Preincubation of appropriate mutant cultures with purified allantoate (commercial preparations contain 17% allantoin), urea, or oxalurate did not significantly increase allantoin uptake. Preincubation with allantoin, however, resulted in a 10- to 15-fold increase in the rate of allantoin accumulation. Two allantoin analogs were also found to elicit dramatic increases in allantoin uptake. Hydantoin and hydantoin acetic acid were able to induce allantoin transport to 63 and 95% of the levels observed with allantoin. Neither of these compounds was able to serve as a sole nitrogen source for S. cerevisiae, and they may be non-metabolizable inducers of the allantoin permease. The rna1 gene product appeared to be required for allantoin permease induction, suggesting that control was exerted at the level of gene expression. In addition, we have shown that allantoin uptake is not unidirectional; efflux merely occurs at a very low rate. Allantoin uptake is also transinhibited by addition of certain amino acids to the culture medium, and several models concerning the operation of such inhibition were discussed.


A new locus (leuK) affecting the regulation of branched-chain amino acid, histidine, and tryptophan biosynthetic enzymes. A locus (leuK) affecting regulation of the leucine operon was selected by isolating a spontaneous Ara+ derivative of an Escherichia coli B/r strain carrying an ara-leu fusion in which the arabinose operon is under leucine control. Genetic analyses by P1 transduction demonstrated that the lesion is located to the right of the galactose operon. Regulation of the biosynthetic enzymes for leucine, isoleucine-valine, histidine, and tryptophan was altered in a strain carrying leuK16. High-level gene expression in the heterozygous merodiploid strain F' leuK+/leuK16) demonstrated the dominance of the mutant allele to the wild-type allele. No apparent effect was observed in the mutant on N-acetylornithinase, a biosynthetic enzyme in the arginine pathway, nor on any of the 18 aminoacyl-tRNA synthetases examined. However, compared with that of the parent strain, the extent of the charging of leucyl-, isoleucyl-, valyl-, histidyl-, and arginyl-tRNA was decreased in the mutant.


Dimensions of Escherichia coli at various growth rates: model for envelope growth. The duplication of Escherichia coli B/r is described based on two independent sequences, the replication of the genome and the growth of the envelope. It is proposed that (i) new envelope growth zones are activated coincident with the initiation of new rounds of chromosome replication; (ii) each zone is active in envelope synthesis from the time of its inauguration to the division which follows the completion of the round of chromosome replication (that is, for C + D min); and (iii) the rate of envelope synthesis at each site is constant, independent of the growth rate. Measurements of the surface areas of two E. coli B/r substrains growing at a variety of rates and during nutritional transitions are consistent with the predictions of the model.


Diameter of cells of a thermosensitive dnaA mutant of Escherichia coli cultivated at intermediate temperatures. Strains of Escherichia coli K-12 carrying the dnaA46 mutation exhibited a progressively decreasing DNA concentration and a progressively increasing cell size as the temperature was raised from 31 to 37 degrees C. Above 37 degrees C, steady-state exponential growth could not be maintained. The increase in average cell size with increasing growth temperature was due to an increase in cell length. There was no change in cell width. This seems to rule out the hypothesis that the increase in cell width in thy strains cultivated on low concentrations of thymine is due to the decrease in DNA concentration which also occurs under these conditions.


Chromosome replication rate and cell shape in Escherichia coli: lack of coupling. The dimensions of Rep- cells of Escherichia coli K-12 were measured and compared with those of their Rep+ isogenic cells (both Thy-), Rep- cells cultivated identically were longer (but not wider), even though both strains were wider when the rate of chromosome replication was slowed down by lowering the thymine concentration supplied. This eliminates the possibility that cell shape is determined by this rate. Simulating Thy+ phenotype by adding deoxyguanosine resulted in shorter Rep- cells when growth was faster. This excludes a simple relationship between cell elongation and growth rate, but is consistent with a linear proportionality between the rate of surface synthesis and growth. Thymine limitation of fast-growing Thy- E. coli K-12 cells is shown to result in loss of their uniform shape and production of bizarre morphologies, apparently due to imbalanced synthesis of wall components.


Salmonella typhimurium mutants lacking protease II. Mutants of Salmonella typhimurium lacking protease II, an endoprotease with trypsin-like specificity, have been isolated. These mutants can be identified by using the chromogenic substrate N-methyl-N-p-toluenesulfonyl-L-lysine beta-naphthyl ester to screen colonies growing on agar for the presence of the enzyme. All of the mutations isolated map at locus tlp (typsin-like protease) which is cotransducible (approximately 1%) using phage P1 with tre (trehalose utilization) at approximately 58 min on the Salmonella map. Double mutants lacking both protease I and protease II have been constructed. These strains grew normally. They were able to degrade abnormal proteins and to carry out protein turnover during carbon starvation at the same rate as the wild type.


Peptidase-deficient mutants of Escherichia coli. Mutant derivatives of Escherichia coli K-12 deficient in several peptidases have been obtained. Mutants lacking a naphthylamidase, peptidase N, were isolated by screening for colonies unable to hydrolyze L-alanine beta-naphthylamide. Other mutants were isolated using positive selections for resistance to valine peptides. Mutants lacking peptidase A, a broad-specificity aminopeptidase, were obtained by selection for resistance to L-valyl-L-leucine amide. Mutants lacking a dipeptidase, peptidase D, were isolated from a pepN pepA strain by selection for resistance to L-valyl-glycine. Starting with a pepN pepA pepD strain, selection for resistance to L-valyl-glycyl-glycine or several other valine peptides produced mutants deficient in another aminopeptidase, peptidase B. Mutants resistant to L-valyl-L-proline lack peptidase Q, an activity capable of rapid hydrolysis of X-proline dipeptides. Using these selection procedures, a strain (CM89) lacking five different peptidases has been isolated. Although still sensitive to valine, this strain is resistant to a variety of valine di- and tripeptides. The ability of this strain to use peptides as sources of amino acids is much more restricted than that of wild-type E. coli strains. Strains containing only one of the five peptidases missing in CM89 have been constructed by transduction. The peptide utilization profiles of these strains show that each of the five peptidases can function during growth in the catabolism of peptides.


Isolation and characterization of a Clo DF13::Tn901 plasmid mutant with thermosensitive control of DNA replication. After nitrosoguanidine mutagenesis, a mutant Escherichia coli strain harboring the Clo DF13::Tn901 plasmid pJN03 was isolated that is thermosensitive (Ts) for growth at 43 degrees C. The mutation responsible for this thermosensitive phenotype resides on the pJN03 plasmid genome. Cells harboring the pJN03 cop-1(Ts) plasmid mutant showed a large increase in plasmid copy number at 43 degrees C accompanied by an increase in the synthesis of plasmid-specified gene products like cloacin DF13 and beta-lactamase. The pJN03 cop-1(Ts) mutant showed uncontrolled plasmid DNA replication at the nonpermissive temperature. Analysis of plasmid deletions showed that the mutation is located in the Clo DF13 map interval from 0 to 12% or 29 to 45%. This implies that native cloacin DF13 and the Clo DF13-specified polypeptides B, C, D, E, and G are not involved in the pleiotropic phenotype of the plasmid mutant pJN03 cop-1(Ts).


Effect of inhibitors of elongation factor Tu on the metabolic regulation of protein synthesis in Escherichia coli. By using inhibitors of elongation factor Tu (L-1-tosylamido-2-phenylethyl chloromethyl ketone [TPCK] and kirromycin), we determined the effect of elongation factor Tu inhibition on the synthesis  of individual components of the translation machinery. The rates of synthesis of individual proteins were measured in double-label experiments using a two-dimensional gel system. TPCK inhibition produce a coordinate decrease in the differential synthesis rates of all components of the translation machinery examined in these experiments. On the other hand, kirromycin inhibition increased the differential synthesis rates of some translation components and decreased the differential synthesis rates of others. These results suggest that the metabolic regulation of synthesis of various translation proteins is not mediated through a common signal.


Outer membrane of gram-negative bacteria. XVIII. Electron microscopic studies on porin insertion sites and growth of cell surface of Salmonella typhimurium. Salmonella typhimurium contains three "major proteins" or "porins" (34K, 35K, and 36K) in the outer membrane. A mutant strain producing only the 35K porin was first grown in media containing high concentrations of NaCl to "repress" the porin synthesis and then was shifted into a medium without NaCl. The newly made porin molecules were then labeled with the ferritin-coupled antibody at various times after the shift, and the samples were examined by whole-mount, freeze-etching, and thin-section electron microscopy. These experiments showed that newly inserted porins appeared as discrete patches uniformly distributed over the surface of the cell and, furthermore, that the sites of adhesion between the inner and outer membrane were most probably the pathway by which the newly made porin molecules appeared on cell surface. The 34K and 36K porins were also inserted in the same manner, since the appearance of new porins at discrete sites all over the cell surface was also observed when cells with wild-type porin phenotype were treated with unlabeled antibody to block existing antigenic sites, subsequently regrown, and labeled with the ferritin-coupled antibody. Since porins comprise a major portion of the densely packed, relatively immobile, "protein framework" of the outer membrane, these results lead us to conclude that the outer membrane grows predominantly by diffuse intercalation rather than by the zonal growth mechanism.


Compact Escherichia coli nucleoids in a highly supercoiled conformation. Escherichia coli nucleoids were visualized in a compact, highly supercoiled conformation at 1 M NaCl. After the salt concentration was lowered to 0.15 M NaCl, the nucleoids uncoiled in beaded fibers in which RNA-mediated structural domains could be distinguished.


Psychological adjustment of nonpatient homosexuals: critical review of the research literature. This paper critically reviews research studies comparing adjustment levels of nonpatient homosexuals and heterosexuals, and concludes that findings to date have not demonstrated that the homosexual individual is any less psychologically adjusted than his heterosexual counterpart.


Cardiovascular system simulation requirements. Circulatory system characteristics are considered with respect to specifying model design parameters for simulators and pulse duplicators. The requirements are investigated to determine what characteristics and parameters are important in design and construction. The specific design depends on the functions of the device to be investigated. The single most important quantity is the modeled proximal capacitance or compliance of the large vessels. More detailed study specifications require more detailed models.


Tissue, cellular and subcellular events at a bone-ceramic hydroxylapatite interface. A new polycrystalline form of hydroxylapatite, durapatite, has been examined as a cortical bone implant in dogs. Utilizing histological and electron optical techniques, it has been found that durapatite does not elicit a foreign body response and that all new bone surrounding the material is normally calcified. Bone was found to strongly adhere to durapatite and preliminary evidence suggests this bonding may be due to direct chemical attachment of bone to the material.


Tri-calcium phosphate as a bone substitute. Strong porous tri-calcium phosphate ceramic has been fabricated, and investigated as a bone implant material. No foreign body reaction was observed, while osteoclastic activity was shown to be involved in biodegradation. Bone mineral was deposited directly onto the surface of the ceramic implant.


Controlled mechanized trepan.

Controlled mechanized trepan. A mechanized trepan is described whose cutting action is halted automatically when the trepan's cutting edge reaches the last 0.03 mm. tissue layer of the cornea. The automatic half of both the motor which advances the trepan as well as the second motor which rotates the trepan is triggered by the sudden change in electrical resistance between the trepan and the patient's internal body fluid, at the final stage of penetration. This automatic feature eliminates the danger of inadvertant damage to the inner structures of the eye.


Biosynthesis of bacterial glycogen. Incorporation of pyridoxal phosphate into the allosteric activator site and an ADP-glucose-protected pyridoxal phosphate binding site of Escherichia coli B ADP-glucose synthase. [3H]Pyridoxal-P can be covalently incorporated into Escherichia coli B mutant strain AC70R1 ADP-glucose synthase by reduction with NaBH4. Two distinct lysine residues can be modified by the allosteric activator pyridoxal-P. Incorporation of [3H]pyridoxal-P in the presence of substrate ADP-glucose + MgCl2 prevents pyridoxylation of an ADP-glucose-protected site and allows modification of the allosteric activator site. Incorporation of [3H]pyridoxal-P in the presence of allosteric effectors fructose-P2, 5'-AMP, or hexanediol-1,6-P2, protects against pyridoxylation of the allosteric activator site, and allows modification of the ADP-glucose-protected site. Incorporation of pyridoxal-P into the allosteric activator site results in modified enzyme of high activity form, even in the absence of fructose-P2. This modified enzyme, when assayed in the absence of fructose-P2, exhibits activation kinetics similar to nonpyridoxylated enzyme assayed in the presence of fructose-P2 and is still inhibited by 5'-AMP. These data suggest that the allosteric activator site of pyridoxylation is the fructose-P2 binding site, and is distinct from the inhibitor 5'-AMP binding site. Incorporation of pyridoxal-P into the ADP-glucose-protected site results in a decrease in enzyme activity. This pyridoxylated lysine could be involved with the binding of thesubstrates ADP-glucose, alpha-glucose-1-P, or PPi, or participate in the catalytic mechanism of the enzyme.


Phosphate binding to Escherichia coli alkaline phosphatase. Evidence for site homogeneity. The reversible, noncovalent binding of inorganic phosphate to Escherichia coli alkaline phosphatase at pH 8 has been examined by equilibrium dialysis at two temperatures and two ionic strengths. Binding occurs with a stoichiometry of two phosphate ions per dimeric enzyme molecule and a single dissociation constant that is not very sensitive to temperature or ionic strength. These results contradict published evidence for anti-cooperative binding of inorganic phosphate to alkaline phosphatase. Reasons are presented for believing that the apparent anti-cooperativity reported by other workers is artifactual.


The functional importance of structural features of ergosterol in yeast. As an approach to the study of the relationship between the structure of sterols and their capacity to function in the lipid leaflet of membranes, various sterols were examined for their ability to support the growth of anaerobic Saccharomyces cerevisiae. A marked dependence on precise structural features was observed in growth-response and morphology. Of the chemical groups which distinguish ergosterol, the main sterol of S. cerevisiae, the hydroxyl group at C-3 was obligatory, and the other groups were found to be of the following relative importance: 24beta-methyl-delta22-grouping greater than 24beta-methyl group greater than delta5,7-diene system = delta5-bond approximately or equal to no double bond. Methyl groups at C-4 and C-14 were inconsistent with activity. Consequently, the data strongly suggest that the normal biosynthetic processes removal of methyl groups from the nucleus and introduction of one in the side chain are of functional significance. A double bond between C-17 and C-20 joining the steroidal side chain to the nucleus had no deleterious effect on the growth process but only if C-22 was trans-oriented to C-13. In the cis-case no growth at all proceeded. This means the natural sterol probably acts functionally in the form of its preferred conformer in which C-22 is to the right ("right-handed") in the usual view. Since the placing of a substituent (OH or CH3) in the molecule at C-20 in such a way that it appears on the front side in the right-handed conformer completely destroyed activity, the sterol apparently presents its front face to protein or phospholipid when complexing occurs.


An active alpha'2beta2 derivative of tryptophean synthase formed by limited proteolysis. A new approach to studying the arrangement of subunits in the multienzyme complex tryptophan synthase is reported. Comparative studies of limited tryptic proteolysis of the alpha2beta2 complex and of the separate beta2 and alpha subunits show that subunit association inhibits two types of proteolysis which occur with the separate subunits: (i) cleavage of the beta2 subunit to two fragments with consequent loss of activity and (ii) complete degradation of the alpha subunit with loss of activity. Trypsin treatment of the alpha2beta complex does, however, result in at least one cleavage of the alpha subunit and yields an active alpha'2beta2 complex. The alpha'2beta2 complex can be resolved into an active beta2 subunit and an active alpha derivative termed alpha'. These two species can reassociate into the active alpha'2beta2 complex. alpha' derivative can be separated into a large fragment of Mr approximately 20,000 to 23,000 and a small peptide by polyacrylamide gel electrophoresis under denaturing conditions.


Biosynthesis of yeast mannan. Properties of a mannosylphosphate transferase in Saccharomyces cerevisiae. A homogenate of mechanically broken, freshly grown Saccharomyces cerevisiae X2180 cells catalyzes the transfer of mannosylphosphate units from guanosine diphosphate mannose to reduced alpha1 leads to 2-[3H]mannotetraose to yield reduced mannosylphosphoryl [3H]-mannotetraose. The product is analogous in structure to the phosphorylated mannan side chains, which suggests that the enzymic activity is involved in mannoprotein biosynthesis in the intact cell. The mannosylphosphate transferase activity, localized in a membrane fraction obtained by differential centrifugation at 100,000 x g, was solubilized by Triton X-155 and purified 250-fold by ammonium sulfate precipitation and by ion exchange and gell filtration chromatographies. The enzyme requires MN2+ OR Co2+ ions for activity and is stimulated by various detergents. The mnn2 and mnn3 mannan mutants of S. cerevisiae possess normal levels of mannosylphosphate transferase activity, whereas the mnn4 mutant cells contain very low, if any, activity. This is consistent with a previous conclusion that the mnn4 mutation affects the mannosylphosphate transferase activity, whereas the mnn2 and mnn3 strains possess phosphate-deficient mannans because they are unable to synthesize the appropriate side chain precursors. A new mannan mutant class with the mnn4 chemotype was isolated, but the mutation proved to be recessive and nonallelic with the mnn4 locus. This new locus is designated mnn6.


Adhesive bonding of various materials to hard tooth tissues. X. Initial rates of adsorption of nickel or copper ions on hydroxyapatite surface. Initial rates of ion-exchange adsorption of nickelous or cupric ions with calcium ions on the surface of synthetic hydroxyapatite were studied in aqueous nitrate solutions. A kinetic interpretation has been proposed. The determination of the initial rates is important for a systematic investigation of adhesion of certain properly designed substances that may mediate a chemical bonding between dental resins and "mordanted" calcified tissues.


Identification of wear particles in tissue after implantation of different plastic materials. A method is shown by which to identify wear particles of implanted plastic materials in tissue. A Mettler FP2 hot stage was used to determine the melting point of different elastomer particles in normal histological sections between the crossed nicols. By using a microcolorimeter Type MPE (Leitz, Wetzlar, Germany), additional information about the molecular degradation of wear particles was obtained.


Mechanics of the knee and problems in reconstructive surgery. Static force transmission at the knee is analysed using measurements from radiographs showing the position of the line of body weight and also the bones of the knee in their correct orientation during function. With this technique it is possible to suggest values for a variety of forces acting at the knee. During function the degree of knee flexion is not as important as the angle that the thigh makes with the vertical. The tension in the extensor mechanism is not the same above and below the patella. Failure to recognise these two features results in fundamental errors. The patella, the effects of patellectomy and of forward displacement of the attachment of the patellar ligament are discussed. The importance of the transmission of force in the coronal plane is emphasised with particular reference to total knee replacement. It is suggested that small errors of geometry, as seen in the anteroposterior radiograph, can produce large changes of load.


Cell division from a genetic perspective. A novel view of the eukaryotic cell cycle is taking form as genetic strategies borrowed from investigations of microbial gene regulation and bacteriophage morphogenesis are being applied to the process of cell division. It is a genetic construct in which mutational lesions identify the primary events, thermolabile gene products reveal temporal order, mutant phenotypes yield pathways of causality, and regulatory events are localized within sequences of gene controlled steps.


Localization of actin in Dictyostelium amebas by immunofluorescence. Antibody prepared against avian smooth muscle actin has been used to localize actin in the slime mold, Dictyostelium discoideum. The distribution of actin in migrating cells is different from that in feeding cells. Migrating amebas display fluorescence primarily in advancing regions whereas feeding amebas show uniform fluorescence throughout. The reaction is specific for actin since the fluorescence observed is blocked when the antibody is absorbed by actin purified from avian skeletal muscle, human platelets, and Dictyostelium. These results, in addition to describing the distribution of actin in D. discoideum, demonstrate that actins from these diverse sources share at least one common antigenic determinant.


[A case of traumatic spondylolisthesis treated by Harrington's method and graft (author's transl)]. This exceptional case of traumatic spondylolisthesis recalls the interest of rapid treatment, and the great interest of Harrington's material both for contention and reduction. Finally the authors emphasise the necissity of completing the procedure by an intersomatic graft by the anterior route.


Relationships among three components of self-concept and same-sex and opposite-sex human figure drawings. In an extension of previous studies, 88 presumably normal Ss were given the Draw-A-Person Test and were asked to make Semantic Differential ratings of their same-sex and opposite-sex figure drawings, as well as their real, ideal, and least-liked selves. Significant positive correlations were found between same-sex figure ratings and ratings of both real self and ideal self, and there was a significant negative correlation between ratings of same-sex figure drawings and ratings of least-liked self. There were no significant correlations between ratings of opposite-sex figure drawings and actual, ideal, or least-liked self ratings. Thus a significant relationship among three components of self-concept and normal Ss' perceptions of their human figure drawings emerged, but only for same-sex figures.


Applicability of the Group Personality Projective Test within a prison population. Administered the Group Personality Projective Test (GPPT) to 60 male offenders incarcerated in a state penitentiary. A board of 10 prisoners selected inmates who clearly had demonstrated one of three patterns of assaultive behavior: undercontrolled aggressives, overcontrolled aggressives, and over controlled psychopaths. A control group was chosen randomly from the prison population, as well. Results failed to support the hypothesis that GPPT scores significantly differ among relatively homogeneous prisoner subgroups or between these groups and the control group of non-assaultive prisoners.


Immunofluorescence studies in granuloma eosinophilicum faciale. Direct immunofluorescence investigations were performed on skin biopsies from five patients with granuloma eosinophilicum faciale (GEF; facial granuloma). An extensive and brilliant granular picture was observed along the basement membrane (BM) of the epidermis and the hair follicles, in the walls of the vessels, in the cellular infiltrates and on the connective tissue fibers. These granules were positively stained by antisera directed against IgG, complement (C3/4) and, although less consistently, against IgA and IgM. IgE was found in one case along the BM, but anti- IgD was negative. Concomitantly heavy fibrillar deposits of fibrin were present in the walls of the vessels and in the cellular infiltrates, together with granular depositions along the BM. The analysis of the complement factors showed that C1q, C4, C3, C3c, C3d and C5 were present in the same pattern as C3/4. These results indicate that GEF can be considered as a chronic form of leukoclastic vasculitis mediated by an Arthus-like mechanism, maintained by an unidentified, persistent antigen or by locally produced Ig aggregates.


The principal stress distribution in a root with a loaded post in model experiments. The principal stress distribution in a root with a loaded post was analyzed in model experiments, in which emphasis was directed to the cervical boundary of the root where the stresses are greatest. Maximum stresses were found in the inner proximal sides, and were stronger when the prepared root canal walls were parallel. When contact between post and root was reduced, stresses decreased. These findings point to the importance of sparing tooth substance in the proximal parts of the canal in order to reduce the risk of breaking the cement layer and loosening the post.


A flexural method for evaluation of metal-ceramic bond strengths. A test technique is presented for evaluating metal-ceramic bond strengths. The test piece consists of a four-point loaded metal beam with porcelain bonded to the central tension side of the beam. The test produced failures at predictable locations and was able to differentiate between metal surface treatments.


Laser evaluation of handpiece contamination. Six different models of ultra-high speed handpieces were evaluated in regard to debris accumulation following cutting through tooth structure. A weight-load machine and a laser particle detector were utilized to evaluate the amount of the debris retained. Amounts of debris accumulated after dry and wet cutting were also evaluated. The effect of simple wiping of the handpieces with alcohol guaze was assessed. The results obtained show that the longer the cutting time, the larger the amounts of debris retained on the handpieces. Dry cutting resulted in smaller amounts of debris entrapped than following wet cutting. The cleaning by wiping with alcohol gauze reduced the amounts of the debris, but is insufficient and cannot be utilized as a single procedure for decontaminating handpieces. The external head design is a cardinal factor in retention of debris: larger but smoother surfaces will retain less debris than smaller but more complicated surfaces. External tubings are debris retention foci.


Bacterial penetration, pulpal reaction and the inner surface of Concise enamel bond. Composite fillings in etched and unetched cavities. The sealing properties of resin-composite resin material applied to acid-etched cavities and adjacent enamel were studied in 40 contralateral tooth pairs. This treatment was found to reduce considerably the risk of ingrowth of microorganisms from the surface of the tooth. The resin material did not have any appreciable irritative effect on the pulp; the same was true for the etching procedure. Etching of lateral enamel walls and margins with an acid gel after the application of a liner on dentinal walls was considered to be the procedure recommended before the application of the combination of unfilled resin and composite resin.


Effect of toothbrushing with different concentrations of chlorhexidine on the development of dental plaque and gingivitis. This study showed that 0.15, 0.10, and 0.05% chlorhexidine gluconate solutions used on the toothbrush subsequent to scaling were for at least 45 days able to maintain plaque and gingivitis scores lower than those obtained 14 days after scaling and oral hygiene instruction. Discoloration of teeth and fillings were the only side effects observed.


Be, Li, and Na redistribution near a porcelain/Ni alloy interface shown by ion microprobe mass analysis. During porcelainization the non-preoxidized alloy develops a Be-rich reaction zone in the interface which separates a Be-depleted alloy from a Li and (to a lesser extent Na) depleted region of the ceramic. Thus, Be diffuses to the interface through the alloy Be degrees leads to Be++ + 2 e- occurs at the interface; some of the electrons are electronically conducted to the porcelain-air interface where they are consumed as 2 e- + 1/2 O degrees 2 leads to O=, and the resulting negatively charged porcelain surface attracts Li+ (and Na+).


Topography and distribution of trace surface metals (Sn, In) on alloys for porcelain-metal restoration: influence of surface treatment. Gold alloys were given five different conditioning treatments prior to porcelain firing. The alloys were examined with a scanning electron microscope and energy dispersive X-ray analyzer. Only two of the alloys had tin and indium present; these were concentrated in particles partially fused to the alloy's surface.


Adhesive bonding of various materials to hard tooth tissues. XV. Neutron activation analysis of dentin sorption of mordant salts. Five metallic chlorides were compared simultaneously, with regard to their interaction with dentin surfaces. Neutron activation analysis was used to measure the quantities absorbed. Each metal was bound by dentin to some extent during a 60-second exposure, and was not removed during a 20-second rinse with distilled water. Quantitatively, the gram-atom amounts of ions sorbed increased in the order Co less than Al less than Zn approximately Cu less than Fe. These mordant salts warrant further study as a possible means of improving adhesive bonding between dental resins (via polyfunctional surface-active comonomers) and dentin.


Pressure distribution in centrifugal dental casting. Equations are developed for liquid metal pressure in centrifugal dental casting, given the instantaneous rotational velocity, density, and certain dimensions of the casting machine and casting pattern. A "reference parabola" is introduced making the fluid pressure concept more understandable. A specially designed specimen demonstrates experimentally the reference parabola at freezing.


Maternal smoking and congenital malformations: an epidemiological study. In a case-control study undertaken in several hospitals in Connecticut, it was found that women who reported smoking more than 20 cigarettes a day during pregnancy had a relative risk of about 1.6 for congenital malformations in the offspring of that pregnancy compared with women who said they had not smoked at all during pregnancy. However, there was no significant increase in risk among women who reported smoking 20 or fewer cigarettes a day during pregnancy compared with those who said they had not smoked at all during pregnancy. The higher risk among moderate and heavy smokers could not be attributed to any of the potentially confounding variables considered in this study; furthermore, it was specific to smoking during pregnancy rather than before pregnancy, and increased with the average amount smoked a day. Nevertheless, because the increase in risk was modest, because response bias could exist in a study of this type, and because no other studies have examined in detail the smoking-congenital malformation hypothesis, further research is needed to determine whether the relationship between maternal smoking and congenital malformations in offspring is causal.


Extrusion of endodontically treated teeth. Extrusion in a vertical direction was used in efforts to retain 14 teeth that had subcrestal fractures, perforations, or caries below the gingival tissue. Indications for the procedure, techniques, and complications are discussed.


Surgical-prosthetic correction of dentofacial deformities. The rehabilitation of optimal masticatory function in many persons who have difficult prosthetic dental conditions can be significantly aided by newer orthognathic surgical procedures. The combined surgical-prosthetic approach for these patients requires close cooperation and communication between the general dentist or prosthodontist and the oral surgeon, particularly because various aspects of the surgical treatment planning for these patients differ greatly from those for patients with complete natural dentitions. A discussion and report of cases illustrate germane aspects of evaluation of conditions, treatment planning, and surgical approaches to the more commonly encountered surgical-prosthetic dental problems.


Acid-etch repair of hereditary type 4 enamel hypoplasia. Defects of the enamel include hypoplasia and hypomineralization. The cause can be local, systemic, or hereditary. A 14-year-old boy had type 4 hereditary hypoplastic enamel. The Nuva-Seal, Nuva-Fil acid-etch technique was used to restore the defect.