Biomedical subjects
Publications and source records attributed to M Austin.
Healthy teeth are very important in the RAF as a nagging toothache could jeopardise a crucial mission. Air force DSAs stationed in Germany are trained to sit the UK National Certificate. Examinations take place twice a year, and last November Michael Austin flew out to test nine hopeful candidates.
In conclusion, GABAA receptors containing the alpha 1 subunit are localized on postsynaptic neurons in the ventral pallidum, mainly in the dorsolateral compartment and on presynaptic terminals in the nucleus accumbens. mu-opioid receptors are localized on postsynaptic neurons in both the nucleus accumbens and ventral pallidum, and therefore may be regulating presynaptic release of enkephalin from the accumbens-pallidal projection. Discrete lesions in the dorsomedial core of the nucleus accumbens will upregulate GABAA receptors in the dorsolateral compartment of the nucleus accumbens in a fashion similar to the upregulation of GABAA receptors in the globus pallidus after striatal lesions. However, larger lesions of the lateral core projection to the dorsolateral compartment of the ventral pallidum do not upregulate the GABAA receptors, suggesting that the mechanisms for upregulation of GABAA receptors are specific to the dorsomedial core or a smaller lesion. The uniqueness of the compartments within the nucleus accumbens and the ventral pallidum are supported by these receptor and mRNA analyses.
In order to lower departmental costs in an ophthalmological outpatient department by reducing wastage, the stability of available chlorine at levels of 280 ppm and 560 ppm in litre solutions of sodium dichloroisocyanurate was investigated over a three-week period. There was no significant decay in available chlorine at these levels in solutions kept at 20 degrees C. Sodium dichloroisocyanurate may be prepared on a weekly instead of a daily basis with an annual saving of 1200 pounds to 1400 pounds.
To assess the sequential changes seen in cerebral blood flow using Single Photon Emission Computed Tomography with 99mtechnetium-hexamethylpropylene amine oxime (99mTc-HMPAO SPECT) in acute ischaemic stroke, 35 patients were prospectively studied from June 1990- to March 1991. Scans were performed during the acute phase (1-7 days), sub-acute phase (8-21 days) and chronic phase of stroke (greater than 1 month). Nine patients underwent scans in all 3 phases, 15 patients had 2 scans, and 11 patients had one scan. The majority of infarcts were in the middle cerebral territory (15 patients), while 4 infarcts were in the posterior cerebral territory and two in the anterior cerebral territory. There was a total of 4 lacunar infarcts. Image analysis was by visual inspection and by semiquantitation using homologous regions of interest in opposite hemispheres. SPECT in the acute phase identified the final vascular territory affected in 19 of 27 patients. There were 8 patients in whom early SPECT predicted the vascular territory as seen on late CT scan when the early CT scan was normal. Hyperaemia or reperfusion in the involved vascular territory was identified in 10 patients on scans performed during the sub-acute phase. Late SPECT scans showed perfusion defects greater than the infarct size seen on CT scan in the majority of patients. In all cases, the perfusion defect on the late SPECT scan was equal to or larger than the defect seen on the acute or sub-acute scan. Crossed cerebellar diaschisis was identified in 8 patients, and cortical/subcortical diaschisis in one patient.(ABSTRACT TRUNCATED AT 250 WORDS)
This study was designed to evaluate the effects of culture-medium temperatures on the growth of known quantities of in vitro inoculum of Neisseria gonorrhoeae. Growth of N gonorrhoeae was significantly greater on room-temperature culture medium than on refrigerated culture medium with inocula of 10(2) and 10(3) colony-forming units. There was no difference between growth patterns on room-temperature and those on refrigerated media when inocula were 10(5) and 10(6) colony-forming units.
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Effective surgical treatment of patients with intractable complex partial seizures depends on accurate preoperative seizure focus localization. We evaluated seizure localization with interictal and immediate postictal single photon emission computed tomographic images of cerebral perfusion using technetium-99m-hexamethyl-propyleneamineoxime (99mTc-HMPAO) in comparison with conventional ictal electroencephalographic (EEG) localization. Thirty-two patients with intractable complex partial seizures were studied. The mean delay from seizure onset to injection was 6.3 +/- 5.3 (SD) minutes. Independent blinded observers assessed the scans for interictal hypoperfusion and postictal focal hyperperfusion. Interictal scans alone were unreliable, indicating the correct localization in 17 patients (53%) and an incorrect site in 3 (9%). When interictal and postictal scans were interpreted together, the focus was correctly localized in 23 patients (72%). There was 1 false-positive study, and 8 patients had inconclusive changes, including 2 with inconclusive depth EEG studies. Postictal hyperperfusion was predominantly mesial temporal and frequently associated with hypoperfusion of lateral temporal cortex. Secondarily generalized seizures tended to show focal hyperperfusion less often than complex partial seizures did (Fisher's exact test p = 0.09). Combined interictal and immediate postictal single photon emission computed tomography with 99mTc-HMPAO is a useful noninvasive technique for independent confirmation of electrographic seizure localization. It may provide a suitable alternative to the use of depth electrode studies for confirmation of surface EEG findings in many patients with complex partial seizures.
Elevated endometrial antibody titers were detected in serum and peritoneal fluid of rabbits with experimentally induced endometriosis. Surgical extirpation of implants or suppression with gonadotropin-releasing hormone agonist resulted in decreased endometrial antibody titers, whereas the antibody titers in untreated rabbits with endometriosis increased significantly. Endometrial implants and normal endometrial tissue had similar proteins by polyacrylamide gel electrophoresis. However, the serum and peritoneal fluid from rabbits with experimentally induced endometriosis had gamma G immunoglobulin antibodies to an endometrial protein with molecular weight of approximately 40 kD. These antibodies were absent in rabbits without endometriosis. Isolation of endometrial antigens eliciting the humoral immune response in endometriosis may aid in the development of a specific antibody marker for endometriosis.
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The Collaborative Family Study (1975-1978), the third phase of the Lipid Research Clinics Program Population Studies, covers 2405 probands and 15,693 of their relatives from nine North American communities. This sample was examined for participation differences across race, sex, locality, educational level, and reason for selection. The participation rates were somewhat lower for blacks, younger age groups, and subjects with lower educational levels. The probands' reason for selection into the study had little impact on the participation of probands or relatives. Moreover, based on information gathered at earlier examinations on eligible Family Study probands, the cornary risk factor profile appeared to be similar among participants and nonparticipants . The available longitudinal lipid data on probands indicated general consistency in lipid levels within subjects over short periods of time, in cholesterol even more so than in triglycerides. Among age strata, the younger subjects showed the least intrapersonal stability, especially for triglycerides.
In mice, Mengovirus produces a fatal encephalitis. Plaque purification of the virus resulted in the isolation of a clone (Mengo- 2T ), which in addition to encephalitis caused diabetes. Microscopic examination of pancreases from infected mice revealed necrosis in the islets of Langerhans and infiltration of inflammatory cells. By immunofluorescence viral antigens were found in the islets, and radioimmunoassays demonstrated a substantial decrease in pancreatic immunoreactive insulin. Studies on susceptibility among inbred strains of mice showed that whereas the D variant of encephalomyocarditis virus caused diabetes only in SJL/J mice, Mengo- 2T caused diabetes in strains of mice resistant to encephalomyocarditis-induced diabetes (i.e., CBA/J, C3H/HeJ, CE/J, AKR/J, C57BL/6J). The ability of Mengo- 2T to induce diabetes in encephalomyocarditis-resistant mice was found to be due to the greater capacity of Mengo- 2T as compared to the D variant of encephalomyocarditis virus to replicate in and destroy the islets of these animals. Although Mengo- 2T and the D variant of encephalomyocarditis virus are antigenically indistinguishable by hyperimmune sera, our studies show that these viruses have different host ranges and tissue tropisms .
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The relationship between the probability of sustaining ventricular fibrillation during occlusion or release of a canine coronary artery and the amount of myocardium made ischemic has never been carefully assessed. We occluded the left anterior descending coronary artery above or below the septal artery for 20 min and then released the ligation. The amount of left ventricle perfused by the ligated vessel was determined by injection of different color monastral dyes above and below the ligation. Despite careful ligature placement immediately proximal or distal to the septal artery, there was wide variation in the amount of left ventricle perfused by the ligated vessel, or myocardium "at risk." Myocardium at risk ranged between 24 and 51 g for ligations placed above the septal artery and 14 and 27 g for ligations placed below the septal artery. Ventricular fibrillation during occlusion and after release correlated significantly with the amount of myocardium at risk. This relationship was well described using the logistic risk regression model. The model predicts uniformly low and uniformly high probability of ventricular fibrillation with small and large amounts of myocardium at risk, respectively, and a direct correlation for midrange values of myocardium at risk. This relationship can account for a substantial portion of non-drug related variability in outcome of antiarrhythmic trials using the canine coronary occlusion or release model.
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