Stimulation-dependent depression of readily releasable neurotransmitter pools in brain. Previously accumulated GABA was released from isolated forebrain synaptosomes with repeated calcium stimulation in elevated-potassium medium. Fractional release (calcium-dependent) in response to a second calcium pulse (90-120 sec later) was depressed to approximately 60% of initial release. Neither initial GABA release nor the subsequent depression of release was affected by variations in the labelling duration. Stimulation-dependent depression of labelled GABA and norepinephrine release was demonstrated from both cerebral cortex and cerebellum synaptosomal preparations. In addition, depression resulted from prior stimulation in the presence of veratridine, A23187 or elevated-potassium. Although release of previously accumulated GABA was depressed by calcium stimulation, the release of GABA accumulated between stimulations was not. Release of this recently accumulated GABA was indistinguishable from the initial release of previously accumulated GABA and larger than the subsequently depressed release from the previously accumulated pools. These data imply (1) that the depressed release resulted from a decrease of available transmitter in pools that support secretion processes, (2) that depressed release did not result from a depression of stimulus-secretion coupling processes, and (3) that transmitter accumulated subsequent to release events is released preferentially to transmitter accumulated prior to the intervening stimulation.


Immunocytochemical localization of glutamate decarboxylase in rat substantia nigra. L-Glutamate decarboxylase (GAD, EC 4.1.1.15), the enzyme which catalyzes the alpha-decarboxylation of L-glutamate to form gamma-aminobutyric acid (GABA), was localized both light and electron microscopically in rat substantia nigra by an immunoperoxidase method. Large amounts of GAD-positive reaction produce were seen throughout the substantia nigra in light microscopic preparations, and it appeared to be localized in punctate structures that were apposed to dendrites and somata. Electron microscopic studies revealed that most of the axon terminals in the substantia nigra were filled with GAD-positive reaction product and formed both axodendritic and axosomatic synapses. Many dendrites were extensively surrounded by GAD-positive terminals which most commonly formed symmetric synaptic junctions, although some formed asymmetric synpatic junctions. The results of this investigation are consistent with biochemical, pharmacological and physiological data which have indicated that neurons of the neostriatum and globus pallidus exert a GABA-mediated, postsynaptic inhibition upon the neurons of the substantia nigra. These findings provide another example in the vertebrate central nervous system where Golgi I projection neurons are inhibitory and use GABA as their neurotransmitter.


Microscope-enlarger for macrophotography of histological sections. A microscope-enlarger is described which can be used to produce 20 cm by 25 cm negatives of histological sections at magnifications up to 1,000 diameters, without loss of image quality or reduction of resolution. Standard flat-field microscope optics are used, and the apparatus is adjustable for Koehler illumination. Various microscope components (nosepiece, condenser carrier, etc.) are mounted upon carriers which ride upon a rigid vertical track. A 20 cm by 25 cm film holder is placed upon the base of the device, and illumination is controlled by a photographic timer. The microscope-enlarger has been used to produce large format negatives of Nissl-stained sections of the barins of sea lamprey larvae and to trace the course of Golgi-impregnated and cobalt-filled cells. Further uses of the device in autoradiographic and histochemical studies are mentioned.


Modification of rabbit head holder to increase speed and accuracy of stereotaxic surgery. Modification of a rabbit stereotaxic head holder is described. The changes are designed to reduce the amount of time required to establish the horizontal zero plane and to increase the accuracy of stereotaxic surgery by providing greater instrument stability.


An ultrastructural analysis of protoplast-spheroplast induction in Cryptococcus neoformans. Protoplasts-spheroplasts of a human isolate of Cryptococcus neoformans were prepared using the gut enzyme of Helix pomatia. The induction process, as studied by transmission electron microscopy, occurred in two stages. Early in the induction process, protoplasts-spheroplasts emerged from whole cells through a break in the cell wall-capsule envelope. Later, a gradual dissolution of the entire cell wall occurred releasing the intact protoplast-spheroplast. A comparison of protoplasts-spheroplasts with normal untreated cells revealed that the degree of cellular vacuolation as well as the resolution of cellular organelles was similar.


Influence of temperature on growth of lipopolysaccharide-deficient (rough) mutants of Salmonella typhimurium and Salmonella minnesota. Smooth strains of Salmonella typhimurium and S. minnesota, and chemotypes Ra, Rb, and Rc, which are deficient in lipopolysaccharide components of the somatic side chains and outer core region, grow normally on nutrient agar and nutrient broth up to 45 degrees C. However, most mutants with defects in the heptose region of the LPS (chemotypes Rd2 and Re) do not grow on this medium at 42 degrees C or above; a few grow at 42 degrees C but not at 45 degrees C. In liquid medium (nutrient broth, or phosphate minimal medium), growth, measured as turbidity or as colony-forming units, stops 60 to 90 min after shift from 30 to 42 degrees C; DNA and protein synthesis cease at the same time. Growth does not reoccur at 42 degrees C; protein synthesis and growth reinitiate upon shift to 30 or 37 degrees C. Growth cessation does not alter cell morphology in the phase-contrast microscope. Growth of heptose-deficient strains at 42 degrees C in nutrient broth is restored by MgCl2 (0.5 mM), NaCl (50 mM), or sucrose (100 mM). Sensitivity to smooth-specific and rough-specific phages, and analysis of LPS composition, indicate that heptose-deficient mutants grown at temperatures from 30 to 45 degrees C, and in the presence or absence of high salt, do not contain heptose or O-specific sugars in their LPS.


Accelerated detection of lymphocytic choriomeningitis virus in diagnostic specimens. Lymphocytic choriomeningitis virus could be demonstrated earlier in mice inoculated with clinical specimens if the mice were sacrificed before they appeared sick for examination by the fluorescent antibody technique. In the procedure, the optimal route for inoculation was intracerebral and the best organ tested for staining was the brain.


The respiratory metabolism of Mycobacterium lepraemurium. The respiratory metabolism of Mycobacterium lepraemurium isolated from Sprague-Dawley rats lepromata using several substrates was investigated. None of the intermediates of the glycolysis cycle as well as of the tricarboxylic acid cycle except succinate was oxidized by purified whole suspensions of M. lepraemurium. Likewise, many sulfur compounds such as cystine, thiourea, thioacetate, thiodiglycol, mercaptoact and some sulfhydryl compounds, e.g., cysteine, dithioerythritol, dithiorthritol, and penicillamine were readily oxidized by murine bacillary suspensions, whereas thioglycolate, thioglucose, and reduced glutathione were oxidized at a slow rate. Succinate was not or was very poorly oxidized by normal cells probably because of impermeability of the cell wall but the addition of succinate to the cell suspensions frozen for 1 min at -40 degrees C considerably enhanced oxygen uptake over the endogenous value. The oxidation of succinate was unaffected by inhibitors rotenone, atabrine, and amytal but was markedly inhibited by thenoyltrifluoroacetone, antimycin A, 2-N-heptyl-4-hydroxyquinoline-N-oxide, and cyanide. The thiol-binding agents, p-hydroxymercuribenzoate and N-ethylmaleimide were also effective inhibitors of succinate oxidation but the process was not affected by uncouplers dinitrophenol, dibromophenol, pentachlorophenol, and carbonyl-cyanide-m-chlorophenylhydrazone. The results indicated that succinate oxidation by M. lepraemurium was mediated by oxidative enzymes involving an electron transport chain with oxygen as the terminal electron acceptor.


Respiratory activity as a determinant of radiation survival response. Respiration is depressed in irradiated bacteria reaching a minimum level in most strains at 1-3 h after exposure when incubated in growth medium. Since a delay in response is observed, direct action on respiratory enzymes is unlikely. The dosage response of respiration varies widely in the strains studied with Do's from 15 kR for Escherichia coli BS-1 to 1200 kR for Micrococcus radiodurans. All strains exhibit two-component dosage-response curves. Escherichia coli BS-1 uniquely possesses a positive-sloped second component suggesting a major disruption of respiratory control. A relationship exists between the responses of respiration and survival to a 50-kR exposure in the strains studied. When E. coli B/r is grown in 0.4% glucose reaching a pH of 5.3, a condition known to increase radiation survival considerably, a large increase in radioresistance of respiration is found. 2-Mercaptoethylamine (MEA), a radioprotective agent, also produces proportionate radioprotection of respiration and survival. In M. radiodurans protection is afforded to respiration at doses which produce no measurable effect on survival. These facts suggest that respiration is a major factor in influencing cell survival and may be the principal mechanism through which chemical agents modify radiation response.


Surgical treatment of hydatid disease of the liver. Hydatid disease in southern Ontario is becoming more frequent because of infection in the large immigrant population. Review of 25 cases of hydatid disease of the liver has clarified the clinical features, diagnostic approach and methods of treatment. The commonest presenting symptoms were pain, mass or hepatomegaly, and jaundice. Diagnosis was confirmed, and cysts were localized, by Casoni skin testing, hepatic scanning and angiography. Surgical treatment consisted either of resection, excision or enucleation, and evacuation of the cyst. Two patients were treated by left lateral segmental resection, 6 by either wedge excision of the cyst or enucleation, and 14 by evacuation of cyst contents with or without drainage with the aid of a technique designed to prevent spillage of cyst contents at operation. None of the 14 treated by means of this technique developed recurrent disease, but in 4 of the patients treated by wedge excision or enucleation the cyst contents spilled at operation, resulting in recurrent disease in 2. Controlled cyst evacuation, with tube drainage for infected cavities and those communicating with the biliary tract is the recommended form of treatment in the management of hepatic hydatid disease.


Pilonidal sinus of the umbilicus.

Pilonidal sinus of the umbilicus. Only 15 cases of pilonidal sinus of the umbilicus have so far been reported. A 16th case is described; it supports the theory of acquired origin of the disease. The case fulfilled the criterion for pilonidal sinus--the 36-year-old man had a hair in the infected umbilical cyst. The cyst and umbilicus were excised. The umbilicus was not reconstructed because of the danger of recurrence. It is recommended that a careful search be carried out for hair in all patients with an infected umbilicus.


Malignant lymphoma of the thyroid gland. Malignant lymphoma of the thyroid gland is a rare entity; only 200 cases have been reported to date since 1960. Four patients with this disease presented at the Kingston clinic of the Ontario Cancer Treatment and Research Foundation. Those with localized malignant lymphoma, particularly the histiocytic types, responded favourably to resection of as much of the tumour as possible and subsequent local radiation with cobalt-60 telecurietherapy (3000 to 4000 rads in 3 to 4 weeks). The results of local radiation alone after a biopsy in patients with inoperable localized diseases are encouraging; it is possible, but not yet established, that some of these patients are cured. It has been suggested that the tumour is dependent on thyroid-stimulating hormone but conclusive evidence is not yet available.


Early medicine and surgery in Calgary.

Early medicine and surgery in Calgary. The medical history of the Calgary area can be divided into three periods: the early period before the coming of the North West Mounted Police in 1874, the middle period from 1875 to 1905, during which Fort Calgary was built and the first surgeons settled in the West, and the third period from 1905 to the present. George Alexander Kennedy was the first surgeon of the middle period. He encouraged proper sanitation, fresh air, and avoidance of cold, damp and dirt. He recommended special treatment for various systemic diseases, used chloroform in October 1880 and was known to have treated skull fractures, extradural hemorrhages, prostatic obstruction, postabortion hemorrhage, ascites and pleural effusion. Henderson, Brett, Lindsay, Rouleau, Lafferty and Mackid were the other six pioneer surgeons of the middle period. Mackid's son Ludwig took over his father's practice after studying in Europe and the United States. When he died in November 1975 at the age of 93, the last link with the pioneer surgeons of Calgary was broken.


Epidemic shigellosis on a worktrain in Labrador. An epidemic of shigellosis occurred on a worktrain in western Labrador in October 1974. During the outbreak 62 persons out of a crew of 91 became ill, 11 having recurrent illness; 14 were hospitalized. Epidemiologic analysis with laboratory confirmation implicated unchlorinated and contaminated lake water as the source of the epidemic. Faulty design of water storage tanks perpetuated the use of contaminated water; hence a second wave of illness occurred. The tanks were then thoroughly drained, cleaned and repaired. Many deficiencies in sanitation measures (most of which have since been rectified) were noted at the site of the epidemic as well as at other locations along the railway. Careful sanitation controls are essential in rapidly developing areas of northern Canada.


Extranodal presentation of non-Hodgkin's lymphomas in the testis. The clinical and pathologic features of six patients, each of whom exhibited a testicular mass as the first sign of a lymphoma, are discussed. All underwent extensive staging procedures. Retroperitoneal lymph nodes and bone were frequent sites of extratesticular involvement early in the disease. Later widespread dissemination to multiple organs occurred in five of six patients. CNS involvement was a prominent feature of advancing disease. One patient was apparently cured by orchiectomy alone. Although the others exhibited partial responses to chemotherapy and radiation, the disease was fatal to all of them within a year of orchiectomy. Early, aggressive systemic treatment of these patients appears necessary.


Cyclophoshamide treatment of patients with localized and regional neuroblastoma: A randomized study. A randomized study was conducted to determine the effect of cyclophosphamide on the rate of recurrence and metastases in children with localized and regional neuroblastoma. One hundred and thirty-four patients were entered and 113 were suitable for analysis. All patients had surgical resection of the primary tumor when possible, postoperative irradiation to the tumor bed when indicated for gross residual disease, and 49/113 received cyclophosphamide, 10 mg/kg/day orally for 7-10 days every 28 days for 1 year. A difference was found in the rate of metastases between the patients who did and did not receive chemotherapy; the overall survival of about 80% in both groups was better than anticipated. All relapses occurred during the first year; there were none in 27 Stage I patients, 8/52 in Stage II and 13/34 in Stage III. Toxicity was minimal, with only two patients developing hemorrhagic cystitis that prevented continued therapy.


Factors influencing survival of children with nonmetastatic neuroblastoma. A randomized study was designed to determine the effect of intermittent oral cyclophosphamide on the rate of metastases in children with localized and regional neuroblastoma. Secondary objectives of the study were to determine the value of the proposed staging system, to measure the influence of the peripheral lymphocyte count on prognosis, and to study the effect of the primary tumor site and regional node involvement. Since there was no difference in survival in the two groups of patients, whether or not they received chemotherapy, all 113 children were treated as a single group for the analysis of the secondary objectives. The proposed staging served as a good indicator of prognosis with a significant difference in survival seen between each of three stages. It was not possible to detect a significant influence by the three other prognostic variables studied, peripheral lymphocytes, primary site and regional node involvement. Small numbers in the various subgroups studied may account for the failure of differences to achieve statistical significance.


Sequential and combination chemotherapy of advanced gastric cancer. One hundred and forty-six previously untreated patients with advanced gastric cancer were assigned at random to therapy with the following regimens: 1) Methyl CCNU alone; 2) Methyl CCNU with cyclophosphamide induction; 3) 5-fluorouracil (5-FU) + methyl CCNU; and 4) 5-FU + methyl CCNU with cyclophosphamide induction. Cyclophosphamide induction produced an objective response rate of only 8%. In addition, it added to hematologic toxicity and detracted from the therapeutic activity of subsequent treatment. Methyl CCNU was relatively ineffective therapy with an overall objective response rate of 8%. The response rate to 5-FU + methyl CCNU without cyclophosphamide induction was 40% and this was significantly superior to all other regimens. The survival time of all patients treated with 5-FU + methyl CCNU was significantly superior to that of all patients treated with methyl CCNU alone.


A comparative study of the antitumor effectiveness of E. coli and Erwinia asparaginases. The relative antineoplastic effectiveness of E. coli and Erwinia asparaginases was tested against lymphoid leukemias EARAD-1 and L5178Y/CA55. E. coli and Erwinia asparaginases had similar clearance rates from plasma in mice, and at a dose of 250 IU/kg body weight both enzymes lowered plasma asparagine to undetectable levels. Nevertheless, the dosage of Erwinia asparaginase needed to cause similar prolongation of median survival time in leukemic mice was at least twice that of E. coli asparaginase. The factors which may be responsible for the more potent therapeutic effectiveness of the E. coli asparaginase are discussed.


Mutagenicity of cyclic nitrosamines in Escherichia coli following activation with rat liver microsomes. Ten cyclic nitrosamines were tested for mutagenicity in Escherichia coli after incubation in vitro with 9000 X g microsomal supernatants prepared from rat liver, and the results were compared with carcinogenicity data from the same species. None of the compounds was mutagenic in the absence of microsomes. Seven carcinogenic compounds, nitrosopyrrolidine, nitrosopiperidine, nitrosohexamethyleneimine, nitrosoheptamethyleneimine, nitrosomorpholine, dinitrosopiperazine, and dinitrosohomopiperzine, were mutagenic after microsomal activation. One compound, nitrosohepamethyleneimine, was toxic to the bacteria. Two noncarcinogens, 1-nitrosopiperazine and 1-methyl-4-nitrosopiperazine, and 1 strong carcinogen, 2,6-dimethyldinitrosopiperazine, were not mutagenic with or without microsomal incubation. The liver microsome preparation activated equally well those compounds that are liver carcinogens in Sprague-Dawley rats, and compounds for which the liver is not a target organ.


Correlations between humoral immunity and successful chemotherapy-immunotherapy. Experiments were designed to evaluate the characteristics of the humoral immune response induced by active immunotherapy, both specific (neuraminidase-treated tumore cells) and nonspecific (Bacillus Calmette-Guérin organisms), in the L1210-C57BL/6 X DBA/2F tumor-host system. Tumor burden was minimized with chemotherapy (1,3-bis-(2-chloroethyl)-1-nitrosourea) prior to immunotherapy. A marked increase in the concentration of serum immunoglobulins (immunoglobulin M, immunoglobulin G, and immunoglobulin G) was observed following successful therapy. The highest concentration of these immunoglobulins was found in mice given both Vibrio cholerae neuraminidase-treated cells and B. Calmette-Guérin after chemotheraphy. Tumor-specific immunoglobulin M and immunoglobulin G, as measured by indirect immunofluorescnece, were detected in the sera during the course of successful therapy. Positive immunofluorescence was not observed with progressive sera. Complement-dependent cytotoxic activity against L1210 cells was first detected 5 days after immunotherapy, and increased for several weeks. A high level of cytotoxic activity correlated with successful therapy, whereas low levels were foun in treated mice with recurring tumors. Serum cytotoxicity was not detected in untreated mice with progressively growing tumor.


Mechanism of Bacillus Calmette-Guérin-induced suppression of metastases in a poorly immunogenic fibrosarcoma. Bacillus Calmette-Guérin (BCG) reduces the rate of spontaneous pulmonary metastases from a poorly immunogenic fibrosarcoma. To be effective, BCG (1 X 10(6) organisms) must be given in admixture with (1 X 10(6)) tumor cells at the time of transplantation. Reduction of metastasis at this dosage of BCG occurs without a change in the size of the primarytumor or the extent of necrosis within it. Tumors transplanted in admixture with spleen cells from BCG-exposed donors reduced the number of metastases, while spleen cells from normal or tumor-bearing donors had no effect on metastases. Fewer total tumor cells and clumps are collected from the venous effluent of tumors transplanted with BCG than from control tumors. The BCG-treated tumors have more host macrophages intimately associated with the effluent tumor cells then did controls. These data indicate that BCG can inhibit the metastatic potential of a weakly immunogenic fibrosarcoma. The mechanism of this effect appears to be a depression of entry or tumor cells into the tumor vascular channels which may be related to the interaction of tumor cells with BCG-stimulated macrophages.


Mutagenicity and cytotoxicity of benzo(a)pyrene arene oxides, phenols, quinones, and dihydrodiols in bacterial and mammalian cells. Twenty-nine benzo(a)pyrene derivatives were tested for mutagenic acitivity without metabolic activation in Salmonella typhimurium strains TA98, TA100, and TA1538 and in Chinese hamster V79 cells. The compounds studied included 4 arene oxides, all 12 isomeric phenols, 5 quinones, and 8 dihydrodiols. Benzo(a)pyrene 4,5-oxide was the most mutagenic of the compounds tested in both the bacterial and mammalian systems. The other arene oxides [benzo(a)pyrene 7,8-, 9,10-, and 11,12-oxides] were only weakly mutagenic in the S. typhimurium strains. However, in Chinese hamster V79 cells benzo(a)pyrene 11,12-oxide. Among the phenols, 6-hydroxybenzo(a)pyrene and 12-hydroxybenzo(a)pyrene were moderately mutagenic in strain TA98 of S. typhimurium, and 6-hydroxybenzo(a)pyrene was moderately mutagenic in V79 cells. The other 10 phenols, 5 quinones [benzo(a)pyrene 1,6-, 3,6-, 4,5-, 6, 12-, and 11,12-quinones] and 8 dihydrodiols [benzo(a)pyrene cis-4,5,trans-4,5-, cis-7,8-, trans-7,8-, cis-9,10-, trans-9,10-, cis-11,12-, and trans-11, 12-dihydrodiols] were eitherinactive or only weekly mutagenic. 1-Hydroxybenzo(a)pyrene and 3-hydroxybenzo(a)pyrene were weakly mutagenic in strain TA98 of S. typhimurium, and benzo(a)pyrene 7,8-dihydrodiol was weakly mutagenic in V79 cells. Benzo(a)pyrene 11,12-quinone was extremely cytotoxic to the V79 cells but had no observable toxicity in the bacterial strains.


Mutagenicity and cytotoxicity of benzo(a)pyrene benzo-ring epoxides. Four benzo-ring epoxides of the environmental carcinogen benzo(a)pyrene (BP) were tested for mutagenic and cytotoxic activity in 3 strains of Salmonella typhimurium (TA1538, TA98, and TA100) and in Chinese hamster V79 cells. Although very unstable in aqueous solution, 7beta,8alpha-dihydroxy-0beta,10beta-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene (diol epoxide 1), with the 7-hydroxyl group on the same face of the molecule as the epoxide oxygen, was 1.5 to 4 times as mutagenic in the bacterial strains as was its more stable stereoisomer 7beta,8alpha-dihydroxy-9alpha,10beta-epoxy-7,8,9.10-tetrahydrobenzo(a)pyrene (diol epoxide 2). In V79 cells, diol epoxide 1 had one-third the mutagenic activity of diol epoxide 2 but was at least 10 times more labile than diol epoxide 2 in the tissue culture medium. The half-life of diol epoxide 1 in tissue culture medium was about 30 sec, whereas the half-life of diol epoxide 2 was between 6 and 12 min. 9,10-Epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene, which is saturated in the benzo ring, is also very unstable and has mutagenic activity equal to or greater than diol epoxide 1 in the bacterial and mammalian cells. 7,8-Epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene was more stable in aqueous solution than any of the 9,10-epoxides of BP but was much less mutagenic in both the bacterial and mammalian cells. In v79 cells, diol epoxides 1 and 2 and 9,10-opoxy-7,8,9,10-tetrahydrobenzo(a)pyrene were more than 40 times more cytotoxic than 7,8-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene. The mutagenicity of the 2 tetrahydro epoxides toward strain TA98 of S. typhimurium was readily abolished by purified epoxide hydrase, whereas the mutagenic activity of the 2 diol epoxides was relatively unaffected by coincubation with the enzyme.


Participation of teratocarcinoma cells in mouse embryo development. Teratocarcinoma cells (OTT 6050) from 129 SvSl C P mice were transferred into blastocysts from random bred Swiss albino mice. The blastocysts were placed in the uteri of foster mothers and the adults resulting from these blastocysts were studied for evidence of an effect of the transferred malignant cells. Sixty adults resulted from the experiments, and one of the adult mice that had received teratocarcinoma cells in the blastocyst stage showed several stripes of agouti hair. All the adult animals received grafts of skin from animals identical to those supplying the cells. The animals that resulted from blastocysts into which cells had been transferred maintained skin grafts for a significantly longer period than did controls. These experiments indicate that the transferred malignant cells were able to establish small colonies in the embryos and that some of these cells persisted into the adult.


Neural basis for the genesis and control of arrhythmias associated with myocardial infarction. Alterations of autonomic tone appear to have important effects on the electrical stability of the heart. Since altered electrical stability, ventricular fibrillation, is the cause of death in the majority of patients who die from ischemic heart disease, the effects of the autonomic nervous system on ventricular electrical stability have been examined. Increased vagal tone increases the electrical stability of the heart and reduces the incidence of spontaneous ventricular fibrillation after coronary occlusion. These salutary effects of increased cholinergic tone appear to be mediated by cholinergic innervation of the ventricular conducting system. Conversely, increased adrenergic tone decreases the electrical stability of the heart and increases the propensity of the heart to develop ventricular arrhythmias during coronary occlusion. The interaction of the adrenergic and cholinergic system during myocardial ischemia may be one of the important determinants of survival in patients with coronary artery disease and acute myocardial infarction.


Autonomic nervous system and arrhythmias: studies in the transplanted denervated human heart. The function of the cardiac autonomic nervous system (ANS) was evaluated by comparison of normal subjects with cardiac transplant recipients. By use of standard intracardiac His bundle recording techniques, the following conclusions regarding basic cardiac electrophysiology were drawn: (1) the sinus node functions normally at rest despite autonomic denervation; (2) the AV node does not show the expected decrease in functional refractory period with increased heart rate in the denervated state, and (3) the adrenergic receptor of the cardiac conduction system does not depend upon autonomic innervation to function normally. Electrophysiologic studies of digitalis demonstrated: (1) in therapeutic doses, the AV nodal blocking effect of digitalis is autonomically mediated; (2) sinus node slowing by digitalis also requires an intact autonomic innervation. Arrhythmia analysis in 47 transplant patients revealed an increased incidence of ventricular arrhythmias in autonomic cardiac denervation. In addition, sudden death in the ischemic denervated heart does occur, weakening the concept of a primary role of the cardiac ANS in this phenomenon.


Central and peripheral catecholamine mechanisms in circulatory control. Catecholamine-containing neurones participate in cardiovascular regulation not only through the peripheral sympathetic nervous system but also by central nervous adrenergic mechanisms. Impairment of peripheral sympathetic activity leads to baroreflex impairment and postural hypotension. While changes in central function may alter baroreflex sensitivity, supine hypotension with preservation of postural compensation is more common. Levodopa has been demonstrated to exert both central and peripheral effects on blood pressure in parkinsonian patients.


Orthostatic hypotension in neurological disease. It is now recognized that orthostatic hypotension occurs as a complication of many neurological diseases. An account is given of some of those in which it may develop. The pathological lesions frequently allow studies to be made of physiological mechanisms remaining in the isolated parts of the nervous system. For example transection of the cervical spinal cord causes complete separation of peripheral sympathetic pathways from the control of the brain. It was possible, therefore, to examine the control of renin release and also cerebral blood flow regulation during change of blood pressure in patients with some of these disorders. Evidence has been obtained that the renin-angiotensin system is active in paraplegia and in many other patients with orthostatic hypotension. In addition symptoms of cerebrovascular insufficiency are minimized by the retention of autoregulation of cerebral blood flow (CBF) in patients with failure of sympathetic function. Autoregulation maintains CBF within wide limits of blood pressure and symptoms of orthostatic hypotension only develop if the blood pressure falls below the lower limit, usually about 70 mm Hg.


[Orthostatic hypotension in the aged].

[Orthostatic hypotension in the aged]. Caird and his colleagues reported posture-dependent falls in systolic blood pressure of 20 mm Hg and more in 24% of a population aged 65 and above. In about 5% of the group, moreover, the falls were in excess of 40 mm Hg. Our investigations in 160 residents in an old people's home in the age range 59-88 years largely confirmed Caird's figures. Using Schellong's test we recorded systolic pressure falls of 20 mm Hg and more in 25% of our subjects. These cases of circulatory dysregulation were all manifestations of the hypodynamic form of the orthostatic syndrome. This means that only systolic blood pressure fell, diastolic pressure as well as heart rate being largely unaffected. The phenomenon appears to be due to age-related deterioration in circulatory regulation; at least no evidence has been found to suggest that it has a specific aetiology. In a double-blind cross-over study the effect of dihydroergotamine (DHE) was compared to placebo in 40 patients. Half the patients were given 2 mg DHE three times daily for 14 days and the other half placebo tablets; following 1 week's wash-out, the treatments were then reversed for a further 2-week period. Schellong's test (measurement of blood pressure and pulse after 10 min in the supine position and then after 1, 2, 5 and 10 min standing) was performed at the beginning and end of each treatment period. The average falls in upright systolic pressure for all 40 patients were as follows: before treatment 20 mm Hg (150 leads to 130); end of placebo period 19 mm Hg (147 leads to 128); end of DHE periods 7 mm Hg (145 leads to 138). The differences between the values recorded after treatment with DHE and the other two values are statistically significant (p less than 0.05). Similarly there was a significant difference in the numbers of patients experiencing dizziness during Schellong's test (16-17 out of 40 patients before treatment and after placebo, 6 out of 38 patients after DHE). From this finding conclusions can be drawn regarding the causes of vertigo in old age.


Effect of selected drugs on arterial pressure response to upright posture. Orthostatic hypotension may be secondary to a variety of factors, prominent among which is administration of drugs effecting autonomic function. Therapy of orthostatic hypotension has been successful using a directly acting sympathomimetic amine, ethylnorphenylephrine, which has a distinctive spectrum of alpha, beta1, and beta2 adrenergic agonist properties. The directly acting vasoconstrictor, dihydroergotamine, is effective, producing hemodynamic patterns reflecting a selective effect on capacitance vessels. Orthostatic hypotension secondary to the administration of L-dopa should usually respond to peripheral decarboxylase inhibition by agents such as alpha-methyldopahydrazine. The combined administration of monoamine oxidase inhibitors with indirectly acting sympathomimetic amines will increase arterial pressure, but must be considered quite risky in light of inherently poor ability to regulate dose-response relationships and prior clinical experience with excessive arterial pressure elevation.


A controlled study with Dihydergot on patients with orthostatic dysregulation. (1) 36 outpatients with a manifest orthostatic syndrome were the subject of a double-blind study to investigate the influence of Dihydergot and a placebo over a 4-week period. (2) In the majority of subjects, the dosage was 1 tablet (2.5 mg) 3 times a day. (3) In the test group with Dihydergot (17 subjects), a normalization of circulatory regulation occurred in all cases. (4) In contrast, the placebo group (19 patients) showed no changes. (5) The subjective complaints of which only a part can be attributed to the orthostatic syndrome, largely disappeared through the treatment with Dihydergot, while those in the placebo group were not altered. This may be explained by the central stabilizing effect of Dihydergot which complements the hemodynamic properties.


Proliferation of lamellar whorls in arcuate neurons of the hypothalamus of castrated and morphine-treated male rats. A comprehensive ultrastructural examination of one cross-sectional level (middle 1/3) of the arcuate nucleus of the hypothalamus (AH) of male rats several weeks after castration or after two weeks of morphine treatment confirmed a marked increased in lamellar whorls of endoplasmic reticulum in AH neurons in each group. A comparable incidence of AH whorls was not detected in rats treated with lactose, those treated for only 1--3 days with morphine, or in those given testosterone plus morphine for 2 weeks. It is postulated that the testosterone deficiency following either castration or chronic morphine treatment stimulated the observed increase in AH whorls. A close correspondence was noted between the distribution within the AH of neurons containing whorls and those reported by others to contain luteinizing hormone releasing hormone (LH-RH). The possibility that whorls may be a marker for hypothalamic neurons which play a role in the LH-RH regulatory system warrants further consideration.


Histone genes of the sea urchin (S. purpuratus) cloned in E coli: order, polarity, and strandedness of the five histone-coding and spacer regions. Sea urchin (S. purpuratus) histone DNA of constructed plasmid chimeras cloned in E. coli was cleaved with the restriction endonucleases Eco RI, Hind III, Sal I. Bam I, and Hha I. The resulting fragments were ordered and isolated directly from agarose gels or cloned into other plasmids. Each fragment hybridized to one or another of the five histone mRNAs and elucidated the order of the histone genes in each of the cloned fragments. Some DNA did not hybridize to histone mRNAs and was identified as spacer DNA located between coding regions. Total sea urchin DNA was cleaved with restriction endonucleases, fractionated on agarose gels, and hybridized to histone mRNAs or histone DNA. The results revealed the order of the five histone genes in the histone gene repeat unit and demonstrate that the histone spacer DNA have little sequence homology to other genes. ExonucleaseIII digestion of specific linear chimeric histone DNA plasmids followed by hybridization with mRNAs demonstrated the existence of all five histone genes on one strand of DNA and the 5'-3' polarity of that strand. These results, in conjunction with the data of Wu et al. (1976), allow us to construct a map of coding and spacer sequences in the transcribed strand of S. purpuratus histone gene repeat unit: (see article).


The relative positions of sea urchin histone genes on the chimeric plasmids pSp2 and pSp17 as studied by electronmicroscopy. The relative positions of the sea urchin histone genes and the spacer regions on the chimeric plasmids pS p2 and pSp17 have been mapped by hybridizing total histonemessenger RNA to single strands of the plasmid DNAs. The lengths and spacing between the several RNA:DNA duplex regions on the single strands of DNA were measured by the gene 32-ethidium bromide electron microscope mapping method. We find that the genes are interdigitated with spacer sequences of different lengths; that there are three coding sequences on pSp2, all on the same strand, with the relative order H1, H4, and B4; and that there are two coding sequences on pSp17, both on the same strand, corresponding to the messages denoted B1 and B2-B3, where B4, B1, and B2-3 are electrophoretically resolved components of histone mRNA, all of size intermediate between the larger H1 and the smaller H4 message.


A colony bank containing synthetic Col El hybrid plasmids representative of the entire E. coli genome. Using the poly(dA-dT) "connector" method (Lobbanand Kaiser, 1973), a population of annealed hybrid circular DNAs was constructed in vitro; each hybrid DNA circle contained one molecule of poly(dT)-tailed Col El-DNA (LRI) annealed to any one of a collection of poly(dA)-tailed linear DNA fragments, produced originally by shearing total E. coli DNA to an average size of 8.5 x 10(6) daltons. This annealed DNA preparation (12 mug) was used to transform an F+ recA E. coli strain (JA200), selecting transformants by their resistance to colicin El. A collection or "bank" pf pver 2000 colicin El-resistant clones was thereby obtained, 70% of which were shown to contain hybrid Col El DNA (E. coli) plasmids. This colony bank is large enough to include hybrid plasmids representative of the entire E. coli genome. Individual plasmids have been readily identified by replica mating the collection onto plates seeded with cultures of various F- auxotrophic recipients, selecting for complementation of the auxotrophic markers by F-mediated transfer of hybrid plasmids to the F- recipients. In this manner, over 80 hybrid Col El-DNA (E. coli), plasmid-bearing clones have been identified in the colony bank, and about 40 known E. coli genes have been tentatively assigned to these various plasmids. The hybrid plasmids are transferred efficiently from F+ donors to appropriate F- recipients. The use of this method to establish similar colony banks in E. coli containing hybrid plasmids representative of various simple eucaryotic genomes is discussed.


Organomercury poisoning in Iraq: history prior to the 1971-72 outbreak. Mercury has been used medically in the Middle East since time immemorial. Organomercury compounds were first used as seed dressings in Iraq in 1955. During the years 1955-59, 200 cases of poisoning occurred. A more clearly defined outbreak occurred in 1960, involving approximately 1000 hospital admissions. Twelve patients from two families affected in this outbreak were re-examined in 1973, and showed considerable improvement.


RAST using crude and purified anti-IgE.

RAST using crude and purified anti-IgE. The sensitivity of the RAST using anti-IgE in 125I-labelled IgG fractions of sheep antiserum was compared to that using anti-IgE purified by immunosorbent techniques in tests with three allergens (grass pollens, Aspergillus fumigatus and the detergent enzyme "Alcalase") on sera from 248 workers in a detergent factory. Both anti-IgE reagents measure the same antibody but the RAST procedure using the crude anti-IgE reagent is less sensitive than that using the immunosorbent-purified anti-IgE in its ability to detect circulating IgE in subjects with positive skin-prick tests. In general the agreement between positive RAST and positive skin test was improved when only skin tests equal to or greater than 3 mm were considered positive. With Alcalase, antigen non-specific binding by the crude anti-IgE reagent may give false positive results. Optimal conditions for the preparation of allergosorbents with this allergen are defined. Predictive equations relating the results of RAST and skin test show that the hitherto arbitrary definition of a positive RAST result is statistically valid.


The effects of alternate-day corticosteroid therapy on delayed hypersensitivity skin responses. Alternate-day corticosteroid therapy had been shown to have a suppressive effect on delayed hypersensitivity skin responses elicited on repeated skin testing in an asthmatic population. While the clinical meaning is not clear, it indicates that alternate-day corticosteroid therapy may have a subtle effect on cellular hypersensitivity responses.


Use of gas chromatography and mass spectrometry to analyze underivatized volatile human or animal constituents of clinical interest. The study of volatilizable components in human and animal samples by gas chromatography and mass spectrometry is reviewed for the years 1970--1975. Only naturally volatile, underivatized compounds are considered, from sources such as body fluids, tissues, and breath. Where possible, the clinical samples are discussed in terms of normal profiling, aberrations associated with disease states, and specific compound analyses. A brief descriptive technical section is included, stressing types of sample preparation currently being used.


Difficulties and pitfalls in the interpretation of screening tests for the detection of inborn errors of metabolism. A review of factors which may be responsible for false positive and false negative results in a screening program for the detection of inborn errors of metabolism is presented. Administration of medication, dietary therapy, chemical treatment of specimens, delay in analysis, hypersensitivity of procedures utilized, interfering metabolites and inadequate metabolic development or enzymatic maturation in the patient may all produce results resembling an actual inborn error of metabolism. Inadequate nutritional intake prior to procurement of specimen and loss of material during analytical procedures may produce false negative results. As well, certain less severe variants of inborn errors may present in an unusual manner or may only present during periods of stress to the patient. These factors are discussed in relation to the performance of a metabolic screening program. It is suggested that these progrms should be performed by specialized, central laboratories experienced in the complexities of detection of inborn errors of metabolism.


Long-term study of humoral immune response in patients with chronic pyelonephritis. Indirect immunofluorescence was used for the measurement of serum antibody titers against the hemologous urinary strain of infecting organism in patients with a clinical diagnosis of chronic pyelonephritis. The passive hemagglutination technique was employed for comparison. The antibody response of the patients was followed-up for a period of two to four years. In contrast to titers determined by hemagglutination, antibody titers determined by immunofluorescence were found to be persistently elevated, and the indirect immunofluorescence technique is considered a sensitive and reliable method for the serological diagnosis of chronic pyelonephritis.


Control of plasma aldosterone in terminal renal failure before and after nephrectomy and after renal transplantation. In two patients with terminal renal failure the night-day rhythm of plasma aldosterone (PA) renin activity (PRA) and plasma cortisol (PC) were examined before and after bilateral nephrectomy and after renal transplantation. Before nephrectomy changes in abnormally high PA coincided with PC whereas no significant correlation was observed between PA and PRA. In the anephric state secretory episodes of PA occurred independent from those of PC while PRA was undetectable. After renal transplantation a lack of night-day variation in renin secretion was observed in both patients; only one of the two patients showed episodic secretion of PA while PC was suppressed in both patients probably due to the chronic administration of prednisone. Our results indicate, that before nephrectomy under the conditions described in this study plasma aldosterone was predominantly controlled by ACTH. In the anephric state and after renal transplantation other (yet unidentified) factors might have caused episodic secretion of aldosterone. Finally, the lack of night-day variation and secretory episodes in renin secretion after transplantation points to an important role of the sympathetic nervous system in the control of circadian and episodic renal renin release.


Multiple arterial occlusions and hypertension probably caused by an oral contraceptive: a patient in whom the development of renovascular hypertension has been followed. An 18-year-old woman taking an oral contraceptive was admitted to hospital because of a stroke due to occlusion of three branches of the right middle cerebral artery. She later developed renovascular hypertension due to occlusion of one of two renal arteries on the right side. Occlusion of the ceoliac artery was also found. The circumstances suggest that the occlusions were caused by multiple emboli, the source of which could not be identified. The kidney with the circulatory disturbance was shown to have a persistent abnormal renin secretion three and six months after the stroke, but the peripheral renin level was lower at the second investigation. Cardiac function studies revealed an alarming degree of left ventricular hypertrophy, and satisfactory blood pressure control could not be maintained despite increasing antihypertensive therapy. Surgical corrrction of the circulatory disturbance promptly led to normotension without drugs, and the patient has remained normotensive during the postoperative observation period of twelve months. The oral contraceptive was probably responsible for precipitating the vascular occlusions, but no predisposing factors or warning symptoms were present to identify this patient as being at risk.


The evolution of total knee arthroplasty. The current status of knee replacement surgery suggests that high density polyethylene and chrome cobalt alloy or stainless steel are acceptable materials for use in the intra-articular environment of the knee; that prosthetic components of knee units can be firmly fixed in bone with methylmethacrylate; and that a wide range of prosthetic units are available which will provide acceptable clinical results if used within the limits for which they have been designed. The indications for total knee arthroplasty have been designed. The indications for total knee arthroplasty have become reasonably simple and straightforward. Contraindications for the use of the various units available are relatively obscure and very seldom stressed. Each unit available will fail, however, if used under conditions of bone loss, deformity, and ligamentous instability for which it was not designed. The importance of the surgeon understanding and respecting the limitations of the total knee unit he chooses, and skillfully adapting it to the pathologic anatomy and pathophysiology of the patient's knee cannot be overemphasized.


"Uniformed" consent and the wealthy volunteer: an analysis of patient volunteers in a clinical trial of a new anti-inflammatory drug. After a 16-week clinical trial of a new anti-inflammatory drug, the participants were given a factual test to determine whether they had understood and remembered the information given them when consent was solicited. They filled out a questionnaire about their reasons for volunteering and their views on clinical studies and on medical practice in general. Demographic information was also obtained. Two thirds of the participants did not remember that they had been informed about potential risk (gastrointestinal ulceration). Some subjects remembered, but misunderstood, what they had been told; others developed erroneous ideas about the trial and the study drug. The volunteers agreed to participate in the study to help both their own arthritis and that of other patients. They took pride in their self-sacrifice and in being commended by their friends for their altruism. Analysis of the demographic data shows that indigent persons are not necessarily the most likely to participate in clinical trials. Two thirds of the subjects were from the middle class. The median family income was $13,000. To improve the informed consent procedure, we recommend group meetings in which the participants in a clinical trial can discuss the protocol and the risks of the study. Obtaining consent again, after initial anxiety has decreased, may improve comprehension.


Bumetanide, a new loop diuretic.

Bumetanide, a new loop diuretic. The effect of bumetanide on renal function has been compared with that of furosemide and a placebo in a double-blind study of 9 healthy young men. The sequence for oral administration of the drug was subjected to a random assignation based upon the Latin-square methodology under three different conditions. (1) Normal hydration: The administration of bumetanide (2 mg) produced within the next 4 hr a diuresis comparable to that induced by 80 mg of furosemide. Urinary excretion of sodium, potassium, chloride, calcium, and uric acid also followed comparable patterns. Phosphaturia occurred only under bumetanide. The effect of bumetanide seemed longer lasting. (2) Water loading: The effects of bumetanide and furosemide were comparable with the exception of the phosphaturic effect induced by bumetanide. The action of  both diuretics on the diluting segment of the nephron was well demonstrated by the marked depression of CH2O. (3) Water deprivation: The effects of the two diuretics were comparable, including depression tCH20. In none of these conditions did the placebo produce any significant effect.


Side effects of levomethadone and racemic methadone in a maintenance program. Sixty-six patients participated in a double-blind, crossover study comparing side effects, drug use, clinic attendance, and dose changes on levomethadone and d,l (racemic) methadone. The hypothesis under examination was that dextromethadone, while adding no narcotic actions to the racemate, was contributing to side effects. An earlier single-blind pilot study showed that 9 out of 11 side effects improved while patients were receiving levomethadone, but this larger study did not duplicate those results. Analysis of 25 variables showed no significant between levo- and racemic methadone. There appears to be no advantage in levomethadone over racemic methadone in the treatment of patients in maintenance programs.


N-desmethyldiazepam: a new metabolite of chlordiazepoxide in man. Following administration of chlordiazepoxide HCl to man, N-desmethyldiazepam, a known metabolite of diazepam (Valium), was identified in plasma. The metabolite was identified on the basis of its thin-layer chromatographic (TLC) mobility, electron-capture gas-chromatographic (EC-GC) retention time, and mass spectrum relative to authentic N-desmethyldiazepam. Plasma levels of N-desmethyldiazepam in subjects receiving both single and chronic doses of chlordiazepoxide were determined by an EC-GC method with a limit of sensitivity of 10 ng/ml using 2-ml samples and by a radioimmunoassay procedure which had a limit of sensitivity of 20 ng/ml using a 0.1-ml sample. Both assay methods gave good agreement for the levels of N-desmethyldiazepam. In subjects receiving a single 30-mg oral or intravenous dose of chlordiazepoxide, measurable levels of N-desmethyldiazepam in plasma (10 to 60 ng/ml) were obtained 24 to 72 hr after administration. In 5 subjects receiving 10 mg of chlordiazepoxide three times a day, steady-state levels of N-desmethyldiazepam in plasma were reached after about 1 wk of administration. The mean maximum and minimum steady-state levels of N-desmethyldiazepam were 260 and 220 ng/ml of plasma, respectively. Similar steady-state levels were observed on treatment with 30 mg of chlordiazepoxide over 24 hr.


Nortriptyline plasma levels and therapeutic response. Eighteen depressed outpatients were treated for 6 wk with a mean daily dose of 121 mg of nortriptyline. The mean plasma level was 138 ng/ml during treatment. Therapeutic response was monitored by the Zung Self-Rating Depression Scale and the Hamilton Depression Scale administrered by two psychiatrists blind to the tricyclic used, dose, and plasma levels. Eight patients recovered (Hamilton less than or equal to 6) by the fourth week and 12 by the sixth week. During the steady-state (wk 4 to 6) there was a positive correlation between the weekly Hamilton scores and the weekly nortriptyline levels (p less than 0.01). The 9 patients with mean plasma levels between 50 and 139 ng/ml had a better therapeutic response after 6 wk measured by percent recovered (p less than 0.005). Zung score (p less than 0.05), and Hamilton score (p less than 0.025) than the 9 patients with mean plasma levels between 140 and 260 ng/ml.


Asprin and codeine in two postpartum pain models. Aspirin and codeine, standard reference analgesics, are frequently used as positive controls in clinical trials of new oral analgesics. In randomized parallel double-blind studies, single doses of aspirin and codeine were compared with placebo in episiotomy pain (99 patients) and in postpartum uterine pain (130 patients), common models in analgesic trials. With aspirin, 600 and 1,200 mg, in episiotomy pain, analgesia as measured by pain intensity difference (PID) scores began within 1 hr, peaked at the second hour (p less than 0.01), and continued to the fifth hour (p less than 0.01). In uterine pain, responses with aspirin, 650 mg, were observed to be equally good. With codeine, 60 mg, in episiotomy pain measurable analgesia was present by the second hour and was significant at the fourth hour (p less than 0.05); in uterine pain, responses were indistinguishable from placebo throughout an 8-hr time-course. Codeine seemed ineffective and therefore umacceptable as a positive control in uterine pain. These data imply that the two postpartum pain models are qualitatively different: episiotomy pain seems sensitive to both aspirin and codeine, while uterine pain appears sensitive to aspirin but not to codeine.


Effect of renal transplantation on protein binding of drugs in serum of donor and recipient. Blood samples were obtained periodically before and for about 3 mo after renal transplantation from a donor (mother) and a recipient (9-yr-old son with bilateral nephrectomy) for determination of serum protein binding of salicylate and sulfisoxazole. Ten days after the transplant, the recipient had an acute rejection episode which was treated successfully. The free fraction values of the drugs in serum of the recipient was considerably above normal before transplantation, decreased to normal within 2 days after transplantation, increased again several days before the rejection episode and remained elevated for about 50 days, and then returned to normal. Serum protein binding of the drugs in the serum of the donor was decreased for only a few days after transplantation and then returned to normal.


Congenital malformations in the frontonasal area: their pathogenesis and classification. The observation of 235 patients affected by abnormalities in the frontonasal area, has led the author to reinvestigate this complex chapter of the human congenital malformations. A complete critical review of the literature has been made in order to find the possible correlations between the available cases and those previously reported and to establish a simple morphogenetic classification that may embody them all, even transitional forms.


Facial atrophy.

Facial atrophy. The author's personal experience with 84 patients demonstrating varying degrees of facial atrophy is reported. Of these, 59 patients had forms of progressive hemifacial atrophy. Hemifacial atrophy seems best classified into two groups: those who demonstrate inflammatory changes during the course of the disease as opposed to the more benign or noninflammatory types. The inflammatory type of hemifacial atrophy is usually associated with skin and ophthalmic pathology. It is suggested that it is often difficult, if not impossible, to distinguish between Romberg's disease and hemifacial atrophy from scleroderma; therefore, these terms might best be eliminated in classifying hemifacial atrophy. The etiology of facial atrophy remains unknown in the overwhelming majority of cases.


Vertebral malformations and associated somaticovisceral abnormalities. Numerous references to spine abnormalities and associated somatic and/or visceral abnormalities are reported. An implication is present in each that the association is more than just coincidental and some cause and effect relationship might exist. A series of cases was collected in which congenital spine abnormalities were noted on roentgenograms from patients evaluated for varied reasons. Other roentgenograms of these patients and their medical records were reviewed in an attempt to find associated congenital abnormalities. Another group of patients with known congenital visceral malformations had their roentgenograms reviewed to see if they had spinal variations. It was found that patients with congenital vertebral malformations had an extremely high rate of associated visceral abnormalities, especially of the heart and kidneys. Other relationships between the spine and viscera include congenital lesions of the gastrointestinal and respiratory system and other parts of the renal system. This study also suggests the possible relationship between vesicoureteral reflux and spina bifida occulta. Embryologic considerations yield likely reasons for the relationships which have been suggested previously and are emphasised and augmented by this investigation. The supporting argument that a definite relationship exists between spinal variations and visceral abnormalities, as well as the embryologic reasons, is presented in this review of our selected cases and the appropriate literature.


The evolving picture of diabetes.

The evolving picture of diabetes. The clinical picture of diabetes has changed dramatically in recent years. The early promise of insulin has remained unfulfilled. Its beneficial effects have permitted the development of severe complications in a dramatically increased number of diabetics. Present research is encouraging, but the disease obviously requires a determined, aggressive, and concerted attack, so that we may fully understand the nature of the diabetic syndrome, as well as its treatment, cure, and prevention.


Technetium-99m labeled agents for skeletal imaging. Technetium-99m labeled radiopharmaceuticals are the currently accepted agents of choice for skeletal imaging. Their introduction in 1971 literally initiated a new era in clinical bone scanning. The development of techniques for reducing Tc(VII) with Sn(II) provided the means for complexing this useful radionuclide with various phosphorus-containing compounds which were already known to be avid bone seekers. Long chain polyphosphates were widely used at first, but have been superceded by pyrophosphate and its organic analogs, the diphosphonates. Pyrophosphate is characterized chemically by P--O--P bonds, and the diphosphonates by P--C--P bonds. The chemical forms of their complexes with tin and technetium are not known, but they behave in many respects as weak chelates. Labeling efficiencies for 99mTc of 95% or better are routinely obtainable with both "in house" preparations and commercial kits. Proper molar concentrations and ratios of phosphorus-compound to tin are necessary for both for good labeling and to achieve optimum tissue distribution. Unreacted TcO4- and reduced unbound 99mTc are both potential contaminants in these preparations and must be considered in radiochemical quality control. In vivo tissue distribution and kinetics of the 99mTc-Sn-phosphorus compounds differ with details of preparation, category of agent, and clinical status of the patient. Blood clearance is multi-exponential, with skeletal uptake and urinary clearance accounting for most of the activity. Scanning may be started in 2 1/2 to 4 hr, at which time skeletal activity is on the order of 40 to 50% of the injected dose. The primary indication for bone scanning remains the detection of metastases from extraskeletal malignancies, and the 99mTc labeled agents are more sensitive than either radiographs or Fluorine-18 for demonstrating active lesions. In addition, many new applications in evaluating benign bone disease have widened the clinical scope of skeletal imaging which is rapidly becoming one of the most important studies in nuclear medicine.


Radionuclide angiography with 99m technetium-RBCs. When properly labeled 99mTc-RBCs are injected into a patient, these labeled cells are fairly stable in the circulation thus allowing scintigraphic studies on cardiovascular system. Among various modified techniques published for 99mTc-RBCs labeling, incubation of RBCs with 99mTc pertechnetate then with tin yielded 99mTc-RBCs most stable in the circulation. Average labeling efficiency of 99mTc-RBCs was 66%. After an injection of about 10 mCi 99mTc-RBCs, clear images of the heart chambers and major vessels could be obtained using a gamma camera. Resolution of vascular structures improved significantly when images were taken using gamma camera equipped with pinhole collimator. Radionuclide angiography with 99mTc-RBCs was very useful in detection of abdominal aortic aneurysm, evaluation of mediastinal mass--thoracic aortic aneurysm, and detection of abnormality in a smaller vessel such as carotid artery. Advantages of this procedure are (1) the technique is simple and noninvasive; (2) it has capability of functional evaluation by obtaining flow study; and (3) multiple and repetitive static views can be obtained even several hours after an injection.


Differential diagnosis of benign and malignant renal masses. The high incidence of renal mass lesions, particularly the frequent occurrence of renal cysts in elderly patients, makes the differentiation of benign from malignant renal mass lesions an important clinical challenge. Accurate preoperative diagnosis is important for establishing the prognosis and for avoiding unnecessary surgery, with its increased morbidity and expense, when benignity can be established confidently. A broad spectrum of radiographically related imaging and biopsy techniques are currently available for the detection and characterization of renal mass lesions. In addition to plain film findings and radiographic contrast studies, nuclear medicine techniques and ultrasound analysis of renal mass lesions have made significant contribution to accurate differentiation of cysts from solid masses. Ultrasound scanning and cyst puncture in particular have attained critical significance in the workup of renal masses; Several recent publications analyze the accuracy, comparative costs, complications, and cumulative confidence of the various available procedures. An accuracy of 95% or greater appears attainable when definitive interpretation of the appropriate test is technically achieved, The current review will discuss the recent literature concerning renal mass lesions. The techniques and findings which should lead to acceptable confidence in the nonoperative differentiation of renal masses will be discussed. Factors regarding safety, accuracy, and expense will be considered.


European experience with prenatal diagnosis of congenital disease: a survey of 6121 cases. The results of 6121 prenatal diagnoses established by 46 centers in eight West-European countries are reported. The percentage of "spontaneous" abortions following early amniocentesis (1.4%) does not seem to exceed the normal rate of spontaneous abortion in this period of pregnancy. A total of nearly 300 affected fetuses was detected, and in all but 5 instances the parents asked for interruption of the pregnancy. The majority of prenatal monitoring (75%) was carried out because of an increased risk of chromosomal aberration. In the group with higher maternal age 2.8% of the fetuses were affected; this figure was 4.6% for mothers older than 38 years. Monitoring because of an earlier child with trisomy 21 showed 1.3% fetuses with a chromosomal aberration, and 1.7% abnormal karyotypes were detected in the group where amniocentesis was performed for "miscellaneous reasons." In pregnancies where a parental translocation has been demonstrated, 6.7% of the fetuses showed an unbalanced karyotype and 25% were balanced carriers. Also discussed are results and organizatioal problems of prenatal monitoring for inherited metabolic disorders (206 analyses for 23 different enzyme defects) and for neural tube defects (about 2700 cases).


Bronchodilator effect of a new oral beta adrenoreceptor stimulant, Th1165a. A comparison with metaproterenol sulfate. In a single-blind study the short-term effects of oral administration of Th1165a (5, 10, 15, and 20 mg), metaproterenol sulfate (Alupent) (20 mg), and placebo on ventilatory function, pulse rate, and systolic and diastolic blood pressure were compared over a period of six hours in ten patients with stable, reversible obstructive airway disease. Both Th1165a (5, 10, 15 and 20 mg) and metaproterenol administration caused significant bronchodilation of rapid onset (30 minutes), but the bronchodilator effect of Th1165a (10, 15, and 20 mg) was greater and lasted longer (six hours vs three hours) than that of metaproterenol. A dose-dependent bronchodilator effect was recognizable after administration of Th1165a. The 20-mg dose of metaproterenol sulfate and the 5-mg and 10-mg doses of Th1165a produced minimal side effects. Larger doses (15 and 20 mg of Th1165a caused significant increases in pulse rate. Mild and transient tremors were the most common side effect after administration of Th1165a.


Effect of oral administration of delta-tetrahydrocannabinol on airway mechanics in normal and asthmatic subjects. We performed a double-blind study on the effect of oral administration of 10 mg of delta9-tetrahydrocannabinol on specific airway conductance (Gaw/VL) and the maximal expiratory flow at 50% of vital capacity (Vmax 50%) in six control and six asthmatic subjects. In control subjects, there was a slight but statistically significant increase in Gaw/VL after oral administration of delta9-tetrahydrocannabinol; however, there was no significant increase in Vmax 50%. One of the asthmatic patients developed severe bronchoconstriction following administration of delta9-tetrahydrocannabinol; among the remaining five patients, there were variable changes in Gaw/VL and Vmax 50% after oral administration of delta9-tetrahydrocannabinol, but mean changes were not significant. Mild effects on the central nervous system (CNS) were observed in three subjects; six subjects, three of whom had unpleasant mood changes, had more prominent CNS effects. We concluded that oral administration of delta9-tetrahydrocannabinol is unlikely to be of therepeutic value in asthma, since its bronchodilator action was mild and inconstant and was associated with significant CNS effects. Moreover, one asthmatic patient developed severe bronchoconstriction following oral administration of delta 9-tetrahydrocannabinol.


Effect of cardiac, pulmonary, and vascular disease on one-minute oxygen uptake. A simplified method for estimation of one-minute oxygen uptake (VO2-1) during treadmill grade walking at vertical power requirements of 250, 750, and 1,000 kg-meters/min was devised, where power=weight (kg) X grade (fractional) X walking speed. All subjects were men. There were 29 controls, 34 subjects with coronary arterial disease (of whom 18 had had myocardial infarction), nine subjects with diffuse pulmonary disease, and four subjects with ischemic vascular disease. Abnormally reduced values for VO2-1 were related to these diseases and, more specifically, to a history of myocardial infarction and (in pulmonary subjects) to reduced single-breath diffusing capacity. Lowest values of VO2-1 for a group were found in ischemic vascular disease. Reduced response of VO2-1 may therefore be caused by central defects of oxygen transport.


S-carboxymethylcysteine in the fluidification of sputum and treatment of chronic airway obstruction. The clinical results and changes in sputum found in both a short-term inpatient trial and a subsequent long-term outpatient investigation (three-month double-blind controlled study) of 82 patients with chronic bronchitis treated with a new mucolytic agent, S-carboxymethylcysteine (Mucodyne), are reported. Fluidification of sputum with reduction in certain measurements of the viscosity of morning sputum aliquots, associated with improvement in the ability to cough up bronchial secretions, significant increase in sputum volume output, and improvement in ventilation (as estimated by the forced expiratory volume in one second), were observed in both trials as dose-related responses, with an increase in the ease of expectoration and a reduction in cough frequency and dyspnea. Therapy with S-carboxymethylcysteine was well tolerated, and there were no serious adverse effects, either immediate or delayed. We suggest that the effect of the drug in fluidifying sputum may be due to a mucoregulatory mechanism which reverses the sputum macromolecular disturbances seen in chronic bronchitis.


Surgical correction of diffuse supravalvular aortic stenosis involving the branches of the aortic arch. A case of diffuse supravalvular aortic stenosis including the ascending aorta, the aortic arch, and its branches is presented. The operative procedure employed for correction is presented in detail and discussed. This is the first report of the successful surgical treatment of this type of malformation.


Combination amphotericin B-rifampin therapy for pulmonary aspergillosis in a leukemic patient. Pulmonary aspergillosis developed in a 62-year-old man with acute myelogenous leukemia. Therapy with amphotericin B and 5-fluorocytosine was begun. Synergy between amphotericin B and rifampin was demonstrated in vitro, and therapy with firampin replaced 5-fluorocytosine. Progressive clearing of the pulmonary lesion ensued, suggesting in vivo efficacy as well. Further studies of patients utilizing this regimen are warranted.


Circadian variation in 5-hydroxytryptamine levels in human blood. This study investigates, on a circadian basis, the variation in blood serotonin for a group of 64 healthy persons (volunteers of a Bundeswehr-Ausbildungskompanie); a pronounced circadian rhythm of 5-HT has been found. The variation in daily absolute levels is influenced by novelty stress; by this we refer to the stress resulting from initial contact between the person sampling blood and the patient. Obviously this diminishes as blood is repeatedly withdrawn from the same individual. Exposure to this situation results in an overall decrease in serotonin levels and a modification of the circadian pattern.


Drug-induced antinuclear antibodies and lupus syndromes. Drugs capable of triggering the onset of systemic lupus erythematosus may be divided into those that do so by pharmacological properties of their own and those that do so by eliciting allergic reactions which bring about lupus. Drugs in the first group vary in their potency to activate lupus. They all elicit antinuclear antibodies in the majority of patients who receive them but they only cause lupus in a small percentage of patients. This dichotomy suggests that a predisposition is required for the development of lupus upon intake of these drugs. The mechanism whereby these drugs elicit antinuclear antibodies seems to relate to coupling to and/or modification of, nuclear antigens. The patterns of antinuclear antibodies elicited by these drugs in individuals who receive them correlate well with their known reactivity with various nuclear antigens.


Antithrombotic drugs: part I.

Antithrombotic drugs: part I. There are three categories of antithrombotic agents: drugs which prevent fibrin fromation (the anticoagulants and defibrinating enzymes), drugs which prevent platelet adhesion or aggregation (the antiplatelet drugs), and thrombolytic drugs which induce fibrin degradation. Clinical studies have now led to a better understanding of the relative value of these drugs in different thrombotic disorders. In addition, knowledge of the mechanism of action of some of these drugs has recently been much advanced. The anticoagulant drugs in clinical use are heparin and the oral anticoagulants. Heparin is a potent inhibitor of several steps on the intrinsic coagulation pathway through its effect on a plasma cofactor, antithrombin III. its action is immediate, but heparin must be given parenterally. Oral anticoagulants act more slowly, by reducing the hepatic synthesis of biologically active factors II, VII, IX and X, but can be given by mouth. Heparin is therefore most suitable for starting anticoagulant treatment, while oral anticoagulants are generally used for prolonged therapy. The value of the anticoagulants as antithrombotic agents has been best assessed by studying their effectiveness in preventing and treating venous thromboembolic disease. Oral anticoagulants have been repeatedly shown to prevent venous thrombosis and pulmonary embolism in patients at high risk of developing these complications. However, the increased risk of postoperative bleeding has prevented their widespread use for this purpose in surgical patients. Recently, the use of low doses of heparin, given subcutaneously before and after surgery, has been shown to markedly reduce the incidence of venous thrombosis and pulmonary embolism (including fatal pulmonary embolism) after major elective abdominal surgery, and to produce only a slight increase of postoperative bleeding. This represents a major advance in anticoagulant prophylaxis of venous thromboembolism insurgical patients. However, low dose heparin prophylasix is relatively ineffective in patients having hip surgery, and has not been evaluated in patients having other types of orthopaidic surgery. There is direct evidence that antocoagulant therapy prevents death and recurrent embolism in patients who have developed pulmonary embolism, and considerable indirect evidence that it prevents pulmonary embolism, and considerable indirect evidence that it prevents pulmonary embolism (and death from pulmonary embolism) in patients who have venous thrombosis. The incidence of further venous thromboembolism or bleeding during treatment appears to be minimised when heparin is given by continuous intravenous infusion in a dose sufficient to produce a moderate, but no excessive, prolongation of a heparin-sensitive, in vitro coagulation test. The tests most commonly used to monitor heparin therapy was based on either the whole blood clotting time or the activated partial thromboplastin time...


Tobramycin: a review of its antibacterial and pharmacokinetic properties and therapeutic use. Tobramycin is a new aminoglycoside antibiotic with a broad antibacterial spectrum in vitro, and pharmacokinetic properties similar to those for gentamicin. Tobramycin is more active than gentamicin against Pseudomonas aeruginosa and active against many gentamicin resistant strains, but is not active against enterobacteriaceae resistant to gentamicin. Theoretically, tobramycin has an advantage over gentamicin against infections caused by P. aeruginosa, but any advantage in clinical practice has yet to be adequately demonstrated. Clinical experience with tobramycin is considerably less than with gentamicin. Whilst tobramycin appears to offer no clear advantages over gentamicin against sensitive organisms it is indicated in infection caused by strains of P. aeruginosa which are resistant to gentamicin, but sensitive to tobramycin. Like gentamicin, tobramycin acts synergistically with corbenicillin and the cephalosporins. The efficacy of the tobramycin-carbenicillin combination has been shown in endocarditis caused by P. aeruginosa which was unresponsive to gentamicin plus carbenicillin. Ototoxicity and nephrotoxicity similar to that seen with other animoglycosides have been encountered in therapeutic trials with tobramycin and wider clinical experience is necessary to determine the relative incidence of these side-effects with gentamicin and tobramycin used under similar conditions. Antimicrobial activity: In comparative studies, in vitro, tobramycin is more active than gentamicin against clinical isolates of Pseudomonas aeruginosa. Similarly, the inhibitory index, which is the ratio between the serum concentration attained at usual therapuetic doses and the minimum inhibitory concentration, for Pseudomonas aeruginosa is higher for tobramycin than for gentamicin. Against Gram-negative bacteria other than Pseudomonas spp. the spectrum of activity of tobramycin is similar to that of gentamicin. For most species the activity of tobramycin is slightly less than that of gentamicin. Gentamicin is consistently more active than tobramycin against Serratia marcescens. Like other aminoglycoside antibiotics, tobramycin is active in vitro in low concentrations against Staphylococcus aureus. Tobramycin is essentially inactive against Streptococcus pyogenes, Streptococcus faecalis and Streptococcus pneumoniae (pneumococci). Maner aminoglycosides and of other antibiotics against various bacteria in vitro, but comparisons between studies cannot always be interpreted literally because the activity of many antibiotics in vitro, including tobramycin, is influenced by the nature of the culture media and the presence of certain salts. The sensitivity of P. aeruginosa to tobramycin is influenced by the magnesium, and calcium content of the culture media whilst that of all species is reduced by sodium ions. Wide variations in the concentration of these ions may result in divergent MIC values and an inappropriate choice of antibacterial agent to treat pseudomonas infection...


Bone complications of anticonvulsants.

Bone complications of anticonvulsants. Anticonculsant drug-induced disorders in mineral and bone metabolism are apparently quite common. Current evidence indicates that these drugs derange bone metabolism, both through induction of increased hepatic catabolism of vitamin D and its biologically active products, as well as by direct effects on membrane cation transport systems. The significant clinical manifestions of the disorder include rickets with defective bone development, decreased bone mass with increased risk of pathological fracture and reductions in serum calcium levels which may predispose to increased seizure frequency. There is a broad range of clinical presentation with a number of factors -- drug dose, duration of therapy, vitamin D intake, amount of sunlight exposure, degree of physical activity and presence of other concurrent diseases -- which appear to determine the severity of the clinical manifestations. Current evidence indicates that appropriate vitamin D and calcium supplementation can significantly reduce the clinical manifestations of this disorder. All patients receiving chronic anticonvulsant drug therapy should be carefully evaluted for the presence of drug-induced osteomalacia and treated appropriately with vitamin D. This is especially important in those patients in whom the presence of multiple risk factors indicates an increased likelihood of deranged mineral metabolism.


Paediatric anaesthesia: pharmacological considerations. The young infant differs from the adult in his quantitative responses to many anaesthetic drugs and adjuncts. In the neonate, the larger extracellular fluid volume and blood volume, the smaller muscle mass and fat stores, and presumable greater blood flow to the central organs, not only influence the distribution of drugs to their active site but also secondary redistribution. The neonatal hepatic anzyme systems responsible for the metabolism of drugs are incompletely developed or absent. Glomerular filtration, important for drug excretion, is inefficient by adult standards. The neonate has increased toxicity and sensitivity to a variety of sedative-hypnotics, narcotics, and local anaesthetics. On the other hand, the infant requires more suxamethonium (succinylcholine) and ketamine on a weight basis that does the adult. The response of some infants to non-depolarising muscle relaxants resembles that of the myasthenic patients. The rate of uptake of alveolar levels of inhalation anesthetics is more rapid in infants and children than in adults. In addition, the neonate requires more anaesthetic than the adult for a given surgical stimulus. Biotransformation of inhalation anaesthetics is limited in neonates. Awareness of these pharmacological differences and their probable explanations allows one to provide rational, safer anaesthesia to infants.


Ultrastructure of B-cells of Langerhans islets in rats after the administration of L-leucine. The results of studies with electron microscope supported the earlier biochemical findings on the stimulation of insulin secretion with the aid of L-leucine. The changes of the cell organelles of B-cells showed that both the synthesis and the release of insulin were activated, while the secretion by specific granules was unchanged. The stimulation of B-cells was accompanied by numerous membrane-like structures ("myelin-like figures") which were presumably formed from the endoplasmic reticulum.


Pancreatic beta cell replication: effects of hexose sugars. Neonatal rat pancreatic monolayer cultures were utilized to investigate the effects of various hexose sugars on insulin release and beta cell replication. Sugars tested were D-glucose, L-glucose, 3-O-methyl-D-glucose, D-mannose and D-fructose. These agents were added at varying concentrations to a control medium containing a baseline level of 5.5 mM D-glucose. Replication was estimated by incubating cultures with [3H]thymidine and determining the frequency of beta cell labelling in aldehyde-thionin stained radioautographs. Although the addition of D-glucose to the control medium resulted in a concentration-dependent increase in both insulin release and beta cell replication, the sensitivity of these two processes to glucose differed. Insulin release was stimulated by a 2.75 mM elevation in the D-glucose concentration of the control medium, while an elevation of 11 mM D-glucose was required to increase the frequency of beta cell replication. Moreover, while insulin release was maximally stimulated by an 11 mM elevation in the concentration of D-glucose, the frequency of replication continued to rise as the concentration of D-glucose was further increased. The specificity of these responses to D-glucose was demonstrated by the inability of 11 mM L-glucose or 11 mM 3-O-methyl-D-glucose to stimulate beta cell replication. D-mannose and D-fructose were less potent insulin secretagogues than D-glucose on an equimolar basis and neither compound enhanced beta cell replication at a concentration of 11 mM. However, higher concentrations of D-mannose (16.5 and 22 mM) enhanced beta cell replication, while comparable concentrations of D-fructose did not. These results indicate that the sensitivity of insulin release and beta cell replication to D-glucose differ, and that in addition to D-glucose, D-mannose is also capable of stimulating beta cell replication.


Detection of endogenous immunoreactive prolactin in rat mammary epithelial cells during lactation. The question of whether endogenous prolactin might be detectable in normally lactating rat mammary glands (LMG) was examined by light microscopic immunohistochemistry. In an initial study, sections of LMG were incubated sequentially with I) rabbit anti-rat prolactin (APRL); II) anti-rabbit gamma globulin: peroxidase conjugate (ARgammaG-per), prepared from goat anti-rabbit gamma globulin and horseradish peroxidase, and III) 3,3'-diaminobenzidine mixed with H2O2(DAB). Use of this three-step procedure led to staining of stromal, parenchymal and intraluminal elements. However, control procedures which ommitted step I produced similar staining, caused by direct binding of the ARgammaG-per to endogenous tissue components (possibly rat immunoglobulins). This precluded detection of indirect, APRL-linked, binding of ARgammaG-per. In subsequent experiments, direct binding of ARgammaG-per was prevented by preincubating LMG sections with goat anti-monkey gamma globulin (AMgammaG), following which, the three-step reaction sequence (APRL, ARgammaG-per and DAB) led to APRL-dependent staining, both within the alveolar lumina and in the apices of epithelial cells. This staining, presumably of endogenous prolactin, appeared to be specific, since it did not occur when absorbed APRL (APRL admixed with highly purified rat prolactin) was substituted for APRL in step I of the reaction sequence. In contrast, when an incubation with purified rat prolactin was interposed between the AMgammaG pretreatment and the three-step reaction sequence, staining of epithelial elements was intensified, indicating that these cells had contained unoccupied prolactin-binding sites. The apparent presence of both prolactin-binding sites and endogenous immunoreactive prolactin in LMG alveolar cells strongly suggests that this protein hormone can enter these target cells under physiological conditions.


Properties and applications of pyrethroids. Improved understanding of the factors determining the insecticidal activity, the mammalian toxicity, and the stability in air and light of natural and synthetic pyrethroids has led to a series of new compounds with a very favorable combination of properties. Their characteristics include outstanding potency to insects, low toxicity to mammals associated with rapid metabolic breakdown and, in appropriate cases, adequate stability on plant surfaces even in bright sunlight. Initial tests indicate that even the more stable compounds are degraded rapidly in soil, so if the trials at present in progress reveal no toxicological or environmental hazards, within a few years synthetic pyrethroids should be available to control a wide range of domestic, veterinary, horticultural, agricultural, and forest pests at low rates of application.


Control and management of insect populations by chemosterilants. Chemosterilants, i.e., chemical compounds that interfere with the reproduction potential of sexually reproducing organisms, can be used in three new approaches to insect control. In the sterile-insect release technique, the principal problem is to develop compounds and methods for their application that would not result in introducing harmful residues into the environment. Because of the unusual and often unique circumstances connected with releasing large numbers of sterilized insects, the residue problem and its cost-benefit aspects must be examined individually for each intended control or eradication program. In the direct application technique, chemosterilants must meet the same efficiency and safety standards required from approved insecticides. Combined insecticidal and sterilizing activity is characteristic for some compounds now being investigated. In the genetic technique, chemosterilants may be used for inducing heritable changes in the insect's genome under laboratory conditions, and such procedures would not present any residue problems. Only the first two chemosterilant techniques are approaching practical application, and their safety aspects require detailed evaluation and assessment.


Naturally occurring insecticides.

Naturally occurring insecticides. Naturally occurring insecticides are abundant and varied in their effects, though but a few are articles of commerce. Even for these, pyrethrum, nicotine, rotenone, hellebore, ryania, and sabadilla, there is a paucity of information on mammalian toxicology and environmental effects. In general, these materials are characterized favorably by low acute toxicity and ready dissipation in nature. Unfavorable aspects of natural insecticides are the contained mixture of active and inactive components and the low active ingredient content on a crop yield basis pointing to a high unit cost. Natural insecticides can serve additionally as leads to unnatural mimics, of which the commercially successful synthetic pyrethroids are prime examples. The chemical nature, relationship of insecticidal activity to chemical structure, occurrence, production, and utilization, registered uses, metabolism, and insect and mammalian toxicity are reviewed.


Environmental and toxicological aspects of insect growth regulators. Insect growth regulators (IGRs) are a class of new chemicals that interfere with maturation and reproduction in insects. Proposed hypotheses on the biochemical mechanism of action are presented herein. The environmental aspects as metabolism in soils, plants, insects, and animals suggest strongly that these chemicals undergo rapid degradation and metabolism to innocuous metabolites. The toxicological properties determined for registration of the IGR methoprene, isopropyl (E,E)-11-methoxy-3,7,11-trimethyl-2,4-dodecadienoate, reflected no significant effects against any of the species tested. Toxicological evaluations in swine, sheep, hamsters, rats, dogs, rabbits, guinea pigs, and cattle revealed no clinical signs of toxicosis. Additionally, teratological studies in swine, sheep, hamsters, rats, and rabbits also resulted in no observable effects in the animals at the levels administered.


Utilization of pheromones in the population management of moth pests. Pheromones are substances emitted by one individual of a species and eliciting a specific response in a second individual of the same species. In moths (Lepidoptera) generally females lure males for mating by emission of a sex attractant pheromone comprised of either one or more components. Since 1966 the identification of the pheromone blends of many moth pests has allowed investigations into the use of these messengers for population manipulation. Pheromone-baited traps may be used both to detect pest presence and to estimate population density, so that conventional control tactics can be employed only as required and timed precisely for maximum effectiveness. Attractant traps also can be utilized for direct population suppression when the traps are deployed at a density effective in reducing mating success sufficiently to achieve control. A third use pattern of pheromones and related compounds is disruption of pheromone communication via atmospheric permeation with synthetic disruptants. The behavioral modifications involved in disruption of communication may include habituation of the normal response sequence (alteration of the pheromone response threshold) and "confusion" (inability of the organism to perceive and orient to the naturally emitted lure). Disruption of communication employing the natural pheromone components as the disruptant has been most successful, although nonattractant behavioral modifiers structurally similar to the pheromone components also may prove useful. Possible future resistance to direct pheromone manipulation may be expected to involve the evolution of behavioral and sensory changes that minimize the informational overlap between the natural pheromone system and the pheromone control technique.


Role of phermones and kairmones for insect suppression systems and their possible health and environmental impacts. Insects produce pheromones as a chemical communication system to facilitate reproduction. These highly active chemical attractants have been synthesized for some of the most important insect pests, including the boll weevil, gypsy moth, codling moth, tobacco budworm, European corn borer, and several bark beetles. While none of the synthetic sex attractants have yet been developed for use in insect control, they offer opportunities for the future both as control agents and to greatly improved insect detection. Investigations are underway on insect trapping systems employing the phermones and on air permeation techniques to disrupt insect reproduction. The pheromones are generally highly species-specific and are not likely to pose hazards to nontarget organisms in the environment. Toxicological studies indicate that they are low in toxicity to mammals, birds, and fish, but adequate toxicological data are necessary before they can be registered for use in insect control. Another new class of compounds called kaironomes has been discovered. These chemicals are involved in the detection of hosts or prey by insect parasites and predators. Kairomones may prove useful in manipulating natural or released biological agents for more effective biological control of insect pests. No information is yet available on the toxicology of these chemicals.


Degradation, metabolism and toxicity of synthetic pyrethroids. Synthetic pyrethroidal compounds undergo biodegradation in mammals both oxidatively and hydrolytically, and depending on the type of compound, either of the pathways may predominate. Thus, (+) - or (+/-) -trans isomers of the chrysanthemumate ester of primary alcohols such as fenothrin, furamethrin, proparthrin, resmethrin, and tetramethrin (and possibly permethrin, too) are metabolized mainly through hydrolysis of the ester linkage, with subsequent oxidation and/or conjugation of the component alcohol and acid moieties. On the other hand, the corresponding (+)-cis enantiometers and chrysanthemumate of secondary alcohols like allethrin are resistant to hydrolytic attack, and biodegraded via oxidation at various sites of the molecule. These rapid metabolic degradations, together with the presumable incomplete absorption from the gastrointestinal tract, would generally contribute to the low acute toxicity of synthetic pyrethroids. These compounds are neither skin irritants nor skin sensitizers, and inhalation toxicity as well as dermal toxicity are fairly low. Neither is teratogenic in rats, mice, and/or rabbits or mutagenic on various bacterial strains. Subacute and chronic feeding of higher amounts of the compounds to rats invariably causes some histopathological changes in liver; however, these are neither indicative nor suggestive of tumorigenicity. Based on existing toxicological information, the present recommended use patterns might afford sufficient safety margin on human population. However, in extending usage to agricultural pest control, much more extensive investigations should be forthcoming from both chemical and biological aspects, since there is scant information on the fate of these pyrethroids in the environment. Also several of the compounds may be very toxic to certain kinds of fish and arthropods.


Entomopathogens: ecological manipulation of natural associations. The control of insect pests with entomopathogens is unique, in that naturally occurring host-pathogen relations are manipulated to the benefit of man: protecting agricultural crops and forests or controlling insect vectors of disease. The isolation and identification of a virulent pathogen is the initial step in the development of a potential control agent. Production of the pathogen in adequate quantities must be possible either in vivo (insects) or in vitro (artificial medium). To insure usefulness, the pathogen must remain viable in the formulated form and after application in the field. Since inactivation rather than persistence is a problem, the pathogens must be formulated, protected, and applied to insure satisfactory pest control action. Studying the natural host--pathogen interactions will be necessary in order to manipulate the pathogen effectively, by introducing it at the most opportune time in the life cycle of the target pest. Generally, insect pathogens are more selective than conventional pesticides; this will limit their use and industrial development. Development, at least in part, by the public sector may be necessary and desirable. The most promising areas for the use of pathogens are in integrated pest management and in situations where pests have developed resistance to chemical control.