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Biomedical subjects

M Fisher

Publications and source records attributed to M Fisher.

At least 325 records · Page 18Linked to original sources
PubMed1993

Arterial oxygen content and age are determinants of middle cerebral artery blood flow velocity.

BACKGROUND AND PURPOSE: Transcranial Doppler blood flow velocities are inversely related to age and hematocrit, but the relative importance of age, oxygenation, and hemorheological factors has not previously been examined. We evaluated the relative contributions of these factors to middle cerebral artery blood flow velocity in adults with chronic renal failure, a population subject to significant fluctuations in hematologic profile. METHODS: Twenty-six subjects were studied, with arterial shunt blood sampled at the time of transcranial Doppler before dialysis. Twenty subjects from the original cohort were studied twice to examine the effects of intraindividual changes in blood oxygenation and rheology on Doppler velocities. RESULTS: Age (r = -.61, P < .001), high-shear viscosity (r = -.46, P < .02), and arterial oxygen content (r = -.44, P < .05) were all inversely related to middle cerebral artery blood flow velocity. Age was the strongest velocity predictor, accounting for 37% of variance by simple regression analysis. Intraindividual change in arterial oxygen content explained most (54%) of the middle cerebral artery blood flow velocity variation between studies (r = -.74, P < .001). Multiple regression analysis showed that inclusion of additional variables could not account for more velocity variation than change in arterial oxygen content alone. CONCLUSIONS: In this population, age and arterial oxygen content were the most important determinants of interindividual middle cerebral artery blood flow velocity variance and intraindividual middle cerebral artery blood flow velocity variation, respectively.

Adult↗
PubMed1993

Psychiatric morbidity and compulsory admission among UK-born Europeans, Afro-Caribbeans and Asians in central Manchester.

Psychiatric admissions in Central Manchester of Europeans, Afro-Caribbeans, and Asians (within three age-bands) were studied over four years. Among the Afro-Caribbean group there were more single or unemployed persons than in either the Asian or European groups, which suggested greater socio-economic disadvantage. Rates for first admissions and readmissions among Afro-Caribbeans were greater; among Asians they were similar except for the 16-29-year age-group, who tended to have lower rates than Europeans. A higher proportion of Afro-Caribbeans and Asians were psychotic. In the Afro-Caribbean group, the raised rates of admission were largely attributable to increased rates of schizophrenia. The highest rate occurred in second-generation (UK-born) Afro-Caribbeans and was nine times that among Europeans. The police were more frequently involved in the admissions of Afro-Caribbeans compared with Europeans or Asians. Higher proportions of Afro-Caribbeans and Asians who were readmitted were detained under the Mental Health Act 1983, when compared with Europeans.

Adolescent↗
PubMed1993

Effects of a novel NMDA antagonist on experimental stroke rapidly and quantitatively assessed by diffusion-weighted MRI.

We employed diffusion-weighted MRI (DWI) to identify regions of focal brain ischemia during the first 3 hours after permanent occlusion of the middle cerebral artery in rats. Using DWI as early as 30 minutes after the onset of ischemia, it was possible to identify the areas of brain destined to progress to infarction over the next 24 hours in untreated animals, as demonstrated by postmortem evaluation. DWI studies revealed the cerebroprotective effects of a noncompetitive N-methyl-D-aspartate receptor antagonist, CNS 1102, administered 15 minutes postocclusion, both on the cortical and caudoputaminal regions during the initial 3 hours of ischemia. Although the treatment effect lessened over the next 21 hours in a few animals with lower plasma drug levels at 3 hours, postmortem studies demonstrated a 66% reduction in the total volume of infarcted tissue with the treatment and confirmed the DWI results. T2-weighted MRI obtained at similar times revealed little or no abnormality. These results suggest that DWI provides a sensitive in vivo measure of focal cerebral ischemic injury and can assess the beneficial effects of cytoprotective therapy. DWI may be useful in the early evaluation of human stroke patients and in monitoring the effects of cerebroprotective therapies in the clinical setting.

Animals↗
PubMed1993

New uses for calcium channel blockers. Therapeutic implications.

Calcium antagonists block calcium entry into cells, resulting in relaxation of smooth muscle and limitation of the cytotoxic effects of ischaemia in various organ systems. They are most frequently used for clinical conditions requiring vasodilatation, i.e. hypertension and Raynaud's phenomenon, and this also suggests that the most common adverse effect of these drugs for noncardiovascular indications is an unwanted decline in blood pressure. Other uses include treatment of supraventricular arrhythmias and angina. There is some evidence that these drugs retard the development of atherosclerosis. Calcium channel blockers also improve renal reperfusion and may reduce renal insufficiency due to various nephrotoxins, and are particularly useful in renal transplantation for protection against cyclosporin toxicity and post-transplant acute tubular necrosis. These drugs are also useful in pregnancy-induced hypertension and unwanted uterine contraction. Affective disorders and malignancies may be other conditions which benefit from calcium antagonist therapy. Calcium antagonists, in particular nimodipine which is most selective for the cerebral vasculature, have been approved for treating vasospasm after subarachnoid haemorrhage. They are probably also effective for treatment of migraine. Calcium channel blockers may be effective for treating acute cerebral infarction, but results of clinical trials to date have been equivocal, largely because it has been difficult to recruit patients within the short interval after the onset of stroke when these drugs would be most effective, and because of the unwanted hypotensive effect of high doses.

Animals↗
PubMed1992

[Echinococcosis in pregnancy].

Hydatid disease affects sheep and cattle and is caused by the larval form of Echinococcus granulosus. Affected human beings are only chance intermediate hosts. We present a woman admitted in her 22nd week of pregnancy because of upper abdominal pain and persistent vomiting. The presumptive diagnosis of hydatid cyst of the liver was established by ultrasound, X-ray and CT examinations. At laparotomy a 10 x 7 cm hydatid cyst was removed from the liver. She recovered completely and delivered spontaneously at term. There was no evidence of hydatid disease in the newborn or in the placenta.

Echinococcosis, Hepatic↗
PubMed1992

School-based adolescent health care. Review of a clinical service.

OBJECTIVE: To provide recommendations regarding the establishment and maintenance of school-based clinics, based on analysis of data from a clinic located in a New York City high school. DESIGN: Review of demographic, medical, and psychosocial data collected during student visits. SUBJECTS: During 2 1/2 years, 1283 students were seen. The students were 53% girls and 47% boys; 65% black and 25% Hispanic; and 65% grades 9-10 and 35% grades 11-12. RESULTS: There were 7920 visits. Visits were for acute or chronic medical problems (44%), physical examinations and immunizations (25%), gynecologic or sexuality-related issues (17%), and mental health concerns (14%). Psychosocial characteristics of the 378 students who enrolled during the 1989-1990 academic year indicated that only 27% lived with both natural parents, 55% were foreign-born, 37% had repeated a grade at least once, 44% were sexually active, 13% drank alcohol, and 14% had past or present suicidal ideation. CONCLUSIONS: These data demonstrate that a school-based clinic can be involved in the management of a wide range of health care needs for large numbers of at-risk youth. In addition, school-based clinics can serve as a major site for the teaching of medical students and residents, and as a valuable resource for clinical research.

Adolescent↗
PubMed1992

New magnetic resonance techniques for evaluating cerebrovascular disease.

Magnetic resonance (MR) imaging of acute stroke has made important contributions to diagnosis. Several novel MR technologies, now in preclinical and clinical development, will contribute to stroke diagnosis and perhaps help to guide therapy. MR angiography is the most clinically advanced new MR technology and offers the clinician a method to image noninvasively the extra- and intracranial vasculature. Diffusion-weighted MR imaging can demonstrate ischemic lesions quantitatively within minutes of onset in experimental stroke models, and human application is proceeding. Perfusion MR studies can reveal the presence or absence of cerebral perfusion in specific arterial territories. MR spectroscopy can assess tissue metabolites in vivo and reveal changes in these metabolites associated with ischemic injury. The combination of these new MR techniques should provide a plethora of information about the extent of ischemic lesions, associated vascular and perfusion deficits, and metabolic consequences. This information will afford the clinician the opportunity to assess and subtype ischemic stroke patients more rapidly and could be used to monitor therapeutic responses.

Animals↗
PubMed1992

Inhibition of lipid deposition in the hypercholesterolemic rat by clentiazem, a calcium channel blocker.

We studied the effects of clentiazem, a calcium channel blocker (1) on the accumulation of lipid in the aorta, (2) on the level of plasma lipids, and (3) on the number of adherent intimal monocytes and foam cells. Seventy Wistar rats were assigned to one of the following groups: (1) regular diet, (2) an atherogenic diet consisting of regular chow with 2% cholesterol, 1% cholic acid, and 0.5% thiouracil (CCT), (3) CCT supplemented with 5 mg/kg/day clentiazem, and (4) CCT with 25 mg/kg/day clentiazem. Animals were sacrificed after 6 or 12 weeks of diet. Aortas were studied by light microscopy after staining with oil red O (ORO) and/or hematoxylin. ORO staining was quantified in both abdominal and thoracic regions of the aorta. The aortas of the clentiazem groups demonstrated significantly less ORO staining than CCT diet controls in thoracic aorta after 6 weeks and abdominal aorta after 12 weeks. There was no significant difference in the plasma lipid concentrations. The clentiazem-treated groups had fewer numbers of adherent monocytes and foam cells. We conclude that clentiazem inhibits lipid deposition in cholesterol-fed rats without lowering plasma lipid concentrations and that the number of intimal monocytes and foam cells is decreased in the presence of this calcium antagonist.

Animals↗
PubMed1992

Inhibition of stimulated human leukocyte hydrogen peroxide generation by a novel antioxidant, OPC-14117.

Oxygen free radicals generated by leukocytes may contribute to tissue injury after central nervous system (CNS) focal ischemia or trauma. Inhibiting oxygen free radicals has improved outcome in experimental models of these conditions and antioxidant therapy appears promising. We evaluated the ability of a novel antioxidant, OPC-14117, to reduce hydrogen peroxide (H2O2) production by stimulated human polymorphonuclear (PMN) leukocytes and monocytes. Stimulated PMN and monocytes were incubated with several concentrations of OPC-14117 for 20 min and H2O2 production, nmol/1 x 10(6) cells/30 min, was measured. OPC-14117 significantly reduced PMN H2O2 production (P less than 0.001) and monocyte H2O2 production (P less than 0.05). A dose response relationship was observed for both leukocytes, as the 100 microM drug concentration was significantly (P less than 0.05) more effective than the 10 microM concentration. These results demonstrate that OPC-14117 inhibits H2O2 generation by stimulated human leukocytes and support further studies of its effects in disorders such as CNS focal ischemia and trauma, conditions where antioxidant therapy may be beneficial.

Adult↗
PubMed1992

Outcome of gestational diabetes in Bengali Asians living in an east London health district.

The characteristics and outcome of pregnancy complicated by gestational glucose intolerance are described in a consecutive series of 69 Bengali Asian patients and a parallel group of 22 Caucasian patients. The Bengali patients were older and of higher parity than the Caucasians and more frequently required insulin therapy. However, the outcome of pregnancy was similar in terms of antenatal clinic attendance, the number of antenatal hospital admissions, glycaemic control, birthweight and mode of delivery. Of those patients who attended for postnatal glucose tolerance test, 20% of the Bengali population demonstrated persisting abnormality of glucose tolerance, whereas no abnormalities were evident in the Caucasian group. These findings are consistent with the high prevalence and early age of onset of non-insulin-dependent diabetes in Asian populations. The World Health Organisation (WHO) criteria for the diagnosis of impaired glucose tolerance proved insufficiently sensitive for the diagnosis of gestational diabetes. This was particularly demonstrated by four patients with apparently normal glucose tolerance by WHO criteria who subsequently required insulin therapy.

Adult↗
PubMed1992

Substance use in a school-based clinic population: use of the randomized response technique to estimate prevalence.

Students attending school-based clinics acknowledge only minimal involvement with drug or alcohol use. In order to explain this unanticipated finding, we used a statistical method called randomized response to study adolescents in one school-based clinic. The sample consisted of 133 students (57% female; 75% black, 20% Hispanic, 5% other; and 58% grades 9-10, 42% grades 11-12). Using both lifetime and 30-day prevalence rates, these students revealed more cigarette smoking and alcohol use on randomized response than they had on questionnaires completed earlier the same academic year, minimal involvement with either marijuana or cocaine use by either method, and a similar amount of sexual activity by both methods. This study demonstrates that randomized response can be a useful method to generate more truthful group responses from adolescents.

Adolescent↗
PubMed1992

Amplified assay of alkaline phosphatase using flavin-adenine dinucleotide phosphate as substrate.

A simple to use, robust, quantitative, and extremely sensitive colorimetric assay for alkaline phosphatase (EC 3.1.3.1), designed to be used as a detection system in diagnostic assays employing antibodies or gene probes, is described. This technology is based on the novel principle of prosthetogenesis, according to which a purpose-designed substrate (a prosthetogen) for a primary analyte-linked enzyme label is hydrolyzed to produce a prosthetic group for a detector enzyme system. The prosthetogen employed here is a derivative of FAD which is phosphorylated at the 3'-position of the ribose ring (FADP), the label enzyme is alkaline phosphatase, and the detector is a D-amino-acid oxidase/horseradish peroxidase-coupled system. Essentially each turnover of every molecule of alkaline phosphatase produces a molecule of D-amino-acid oxidase for detection. Thus enormous amplification of the initial signal is achieved in short time periods because of the relatively high turnover number of alkaline phosphatase for FADP. The system can be formatted as a stable, preformed, freeze-dried preparation containing all analytical components, which is reconstituted simply by addition of buffer solution. This methodology can quantitate less than 0.1 amol of alkaline phosphatase in 30 min at 25 degrees C using microtiter plates.

Alkaline Phosphatase↗
PubMed1992

Anaphylactoid reaction to iopamiro (after pretreatment).

A patient is described with a past history of an anaphylactoid reaction to contrast media who reacted to nonionic contrast media after pretreatment with antihistamines and steroids. The available options to reduce the incidence of reactions include use of non-ionic contrast which has a reported lower frequency than ionic contrast or some form of pretreatment. Various forms of pretreatment have been described and in the majority steroids and antihistamines are used. We describe a patient who reacted to nonionic contrast after a pretreatment regime.

Anaphylaxis↗
PubMed1992

Hematogenous factors and prediction of delayed ischemic deficit after subarachnoid hemorrhage.

BACKGROUND AND PURPOSE: Delayed ischemic deficits contribute to the high morbidity and mortality rates associated with subarachnoid hemorrhage. We evaluated the potential usefulness of measuring coagulation and hemorheological variables and cardiolipin antibodies for prediction of delayed ischemic deficit after subarachnoid hemorrhage. METHODS: Consecutive patients with subarachnoid hemorrhage were studied. Coagulation and hemorheological variables and cardiolipin antibodies were measured on admission, within 7 days of subarachnoid hemorrhage. A subset of patients was studied on admission and at two subsequent occasions. RESULTS: Sixty-nine patients were studied. Sixty-one of these were without clinical manifestations of vasospasm at admission, and 16 developed delayed ischemic deficit during their hospitalization. None of the laboratory variables measured were significantly different between patients with or without later development of delayed ischemic deficit. Elevation of the fibrin fragment D-dimer was found in the group of eight patients admitted with ischemic symptoms and in 49% (34 of 69) of all patients, but this was not associated with delayed ischemic deficit. Sixteen patients were studied on three occasions; this group showed a significant decrease in hematocrit, an increased white blood cell count, and no change in fibrinogen concentration. Fibrin D-dimer levels rose significantly after surgery (from 5.01 +/- 0.69 to 5.53 +/- 0.58 ln-ng/ml, p less than 0.025) and after onset of delayed ischemic deficit (from 4.71 +/- 0.64 to 5.84 +/- 0.34 ln-ng/ml, p less than 0.01). CONCLUSIONS: Hemostatic measurements, hemorheological variables, and cardiolipin immunoreactivity did not predict delayed ischemic deficit in this population.

Adult↗