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Biomedical subjects

B Schwartz

Publications and source records attributed to B Schwartz.

At least 325 records · Page 18Linked to original sources
PubMed1984

Hypothalamic function in amenorrheic runners.

We have examined temperature regulation in eight amenorrheic runners and gonadotropin response to an opioid antagonist in seven amenorrheic runners, 18 to 29 years of age, running 20 to 70 miles a week. Following equilibration, oral temperature was measured continuously, first in a cold room at 39 degrees F and then in a sauna at 172 degrees F in eight amenorrheic runners, in eight eumenorrheic runners, and in eight control subjects in the early follicular phase of the menstrual cycle. Studies were terminated if a subject's temperature fell below 94 degrees F or rose above 102 degrees F, and all studies were conducted in the afternoon. The rates of temperature change, calculated from total net temperature change divided by elapsed time in the test chamber, were not significantly different among the three groups of women. Seven other amenorrheic runners failed to have any significant changes in luteinizing hormone or follicle-stimulating hormone levels in response to the opioid receptor antagonist naloxone administered as an intravenous infusion at 1.6 mg/hour for 4 hours. If opioids inhibit gonadotropin secretion in exercise-associated amenorrhea, an increase in gonadotropins in response to naloxone would have been anticipated. Although it is possible that the dose of naloxone selected was inappropriate and that temperature responses under other conditions might differ from those of normal women, these data suggest that endogenous opiates do not play a direct role in the amenorrhea associated with exercise and that temperature regulatory centers in the hypothalamus are intact in this disorder, compared with other causes of amenorrhea such as anorexia nervosa. Further studies of hypothalamic function are warranted to test these possibilities.

Adolescent↗
PubMed1984

Haemolytic anaemia in previously healthy adult patients with CMV infections: report of two cases and an evaluation of subclinical haemolysis in CMV mononucleosis.

Whereas haemolytic anaemia is commonly encountered in infants and young children with cytomegalovirus (CMV) infections, it is an infrequent complication of CMV-induced infections in previously healthy adults. The data from 2 such patients are presented. One patient's Hb fell to a level of 36 g/l, and she required prednisone and blood transfusions. Her direct antihuman globulin test (DAT) was positive (IgG), and her red blood cell survival (51Cr) revealed a T 1/2 of 5 d. Both saline-agglutinating and low-molecular-weight cold agglutinins (CA) (4 degrees C) that reacted against both cord and adult cells were identified. In the second case, a moderate haemolytic anaemia (lowest Hb 87 g/l) was accompanied by negative DAT and CA studies. 20 other patients with CMV-mononucleosis were evaluated for evidence of subclinical haemolysis. Reticulocyte counts greater than 3.0% were noted in 9 of these patients. Haptoglobin values were below 0.5 g/l in 13 patients, and a positive DAT was recorded in 3/10 cases. This study documents haemolysis in many non-immunosuppressed adult patients with CMV infections. The mechanism responsible remains obscure.

Adolescent↗
PubMed1984

Enlargement of laser iridotomies over time.

We reviewed the photographs of our patients who have undergone laser iridotomies since 1975. We were able to examine photographs of 21 eyes of 13 patients to determine whether their iridotomies had enlarged over time. We detected an appreciable increase in the size of the iridotomy in seven of the 21. We attempted to determine whether there was any relation between an increase in iridotomy size and several ocular as well as systemic factors, but no such relations could be identified.

Adult↗
PubMed1984

Inhibition of tumor cell line alkaline phosphatase by human peripheral blood monocytes. Correlation with growth inhibitory activity.

Alkaline phosphatase (AP) activity in intact Ag8 cells was measured by a colorimetric assay in which spectrophotometer readings were obtained directly through wells of microtiter plates using a Multiskan ELISA reader. The wide difference between enzymatic activity observed in cells of this cell line and human peripheral blood monocytes permitted an assessment of inhibition of cell line growth in the presence of plastic-adherent peripheral blood cells. Comparison at 24 h of incubation of enzymatic measurements with those obtained using 3H-thymidine uptake showed comparable results, although values obtained with the enzyme were generally lower. Similarly, direct comparison of results obtained by the enzyme-based method showed good correlation with the number of viable tumor cells remaining in culture. Inhibition of AP activity was observed earlier than inhibition of 3H-thymidine incorporation, reaching its peak after 10 h of incubation. This technique has potential application for other enzyme systems and provides a new tool for analyzing mechanisms whereby effector cells are able to control proliferation of transformed cells.

Alkaline Phosphatase↗
PubMed1984

Identification of the APUD endocrine cells of rat fundic mucosa by means of combined amine fluorescence and electron microscopy.

Rat fundic mucosa contains numerous APUD endocrine cells that can take up 5-hydroxytryptophan (5-HTP) and decarboxylate it to 5-hydroxytryptamine (serotonin), detectable by its formaldehyde-induced yellow fluorescence. To identify these cells by electron microscopy, pieces of rat gastric mucosa were incubated with DL-5-HTP. Some specimens were fixed in 4% formaldehyde-0.5% glutaraldehyde, while others were frozen, freeze-dried, and exposed to paraformaldehyde vapors. Thick sections of the Epon-embedded specimens were examined and photographed by fluorescence microscopy, and fluorescing and nonfluorescing cells were identified by electron microscopy in serial thin sections. Control specimens, not incubated with 5-HTP, revealed fluorescence of only the mast cells and EC cells, which were abundant in the pylorus, but rare in fundic mucosa. Specimens incubated with 5-HTP also exhibited numerous yellow fluorescent endocrine cells in fundic mucosa, which cells were found to be the ECL cells; the A-like cells did not fluoresce. In pyloric mucosa, many G and D (D1) cells also exhibited weak or moderate fluorescence after 5-HTP incubation. Thus, this study supports the contention of previous radioautographic studies that the ECL, but not the A-like, cells are the APUD endocrine cells of rat fundic mucosa, that G and D cells also possess some APUD activity, and that EC cells represent the enterochromaffin cells, which normally synthesize and store demonstrable quantities of serotonin.

5-Hydroxytryptophan↗
PubMed1984

Insufflated red cells protect lungs from hyperoxic damage: role of red cell glutathione in scavenging toxic O2 radicals.

Hyperoxia-mediated pulmonary damage may involve formation of toxic oxygen species such as superoxide, hydrogen peroxide, and hydroxyl radical. Intact red cells evidently scavenge these when insufflated in small numbers into the tracheobronchial tree of rats. Such manipulation protects hyperoxic rats for prolonged periods of time and preserves normal pulmonary histology. Of several potential oxygen metabolite scavengers, a role for red cell glutathione seems particularly likely. It has not escaped our attention that an ironic, and previously unsuspected, connotation of our results emerges: namely, that a small degree of spontaneous alveolar bleeding, which is not an uncommon feature in respiratory distress situations, may actually be beneficial to patients--particularly those ventilated with excessive inspired oxygen concentrations. If confirmatory studies from other laboratories are forthcoming, the tracheal insufflation of autologous red cells in ventilated patients might be considered in the future.

Animals↗
PubMed1984

Decrease of anterior ciliary arterial pressure with increased ocular pressure.

The relationship of the ocular pressure to the anterior ciliary arterial pressure was studied by measuring the pressure of the anterior ciliary artery using a modified pressure chamber. Of the 40 subjects, 9 were normal, 16 were ocular hypertensive patients, and 15 were primary, open-angle, glaucoma patients. A significant negative correlation was found between the anterior ciliary arterial pressure and the ocular pressure such that the former decreases as the latter increases. These results support the concept that the blood flow in the anterior ciliary artery is from the inside of the eye to the outside.

Aged↗
PubMed1983

Cooperative groups and community hospitals. Measurement of impact in the community hospitals.

The Eastern Cooperative Oncology Group, composed of major cancer treatment centers, has an outreach program which involves community hospitals in ongoing cancer clinical trials. A prevalence survey was carried out in February 1981 among 104 community hospitals and 21 member institutions to determine the characteristics of patients being treated, their staffing, and reasons why patients were not on protocol studies. The survey sampled 25 (50) consecutive patients from community hospitals (member institutions). The purpose of the study was to assess the impact of a community cancer control program. The results of the study demonstrated that 16% of patients surveyed in the affiliated community hospitals were being treated on a research protocol. In addition, a further 35% had their treatment plan influenced by a protocol. Consequently protocols have impacted directly or indirectly on 51% of the patients. The corresponding figures in member institutions were 23% and 38% for a total of 61%. In studying protocol availability, it was found that 66% of all patients were ineligible for any protocol. Of patients eligible for a protocol but not registered on one, 52% were not registered because of physician preference for a specific treatment. The affiliates surveyed were shown to be on average half as large as member institutions in terms of number of beds and staff size. Also, staff/patient ratios are generally smaller in the community hospitals. The median age of patients was considerably lower than SEER incidence data. Also, elderly patients were slightly more prevalent in community hospitals than in member institutions. A clear relationship between disease stage and age in breast cancer patients was noted with the representation of early-stage disease much higher in young women.

Adult↗
PubMed1983

Case-control study of ocular hypertension.

A retrospective case-control study compared 100 ocular hypertensive patients with 100 ocular normotensive patients matched for sex and age. Interviews were conducted and charts were reviewed to explore demographic, personal, and environmental factors, as well as medical history and refractive error. Multiple logistic regression analyses assessed which factors were independently related to the presence or absence of ocular hypertension. The variables significantly associated with the presence of ocular hypertension were family history of glaucoma, myopic refractive error, absence of liquor intake, history of nonocular surgery, high income, and history of high BP.

Aged↗
PubMed1983

Increased mortality among elderly patients undergoing cataract extraction.

One hundred sixty-seven patients aged 50 years or more had cataracts extracted between Jan 1, 1979, and Dec 31, 1979, at the New England Medical Center, Boston. In comparison with 824 patients who elected one of six other surgical procedures, when data were stratified according to age and sex, patients undergoing cataract extraction had nearly twice the mortality of the reference patients. Analysis indicated diabetic patients did not significantly alter the relative mortality. Our results support the concept that senile cataracts reflect systemic phenomena rather than only local ocular disease.

Aged↗
PubMed1983

Development of cupping and pallor in posterior ischemic optic neuropathy.

A case of arteriosclerotic posterior ischemic optic neuropathy without optic disc edema is described and documented photographically. The development of optic disc cupping and pallor with ischemia in this patient supports the vascular basis for development of similar cupping and pallor in open angle glaucoma and low tension glaucoma.

Aged↗
PubMed1983

Increased pressure of dilated episcleral veins with open-angle glaucoma without exophthalmos.

Six unilateral cases and one bilateral case of dilated episcleral veins with elevated intraocular pressure without exophthalmos are described. Episcleral venous pressure measured on six unilateral cases showed increased pressure in the affected eye compared to the other eye and to normal controls. Two eyes had typical glaucomatous disc and visual field changes. Five had more optic disc cupping and pallor in the eye with the elevated episcleral venous pressure and intraocular pressure. A thorough work-up, including orbital venography in two unilateral cases, carotid arteriography in one and episcleral fluorescein angiography in five cases, failed to show venous obstruction or direct arterio-venous communications. The different diagnoses are discussed. This condition should be considered in unilateral or asymmetrical intraocular pressure elevation and in those patients with chronically red eyes without discharge.

Aged↗
PubMed1983

Interference fringe scale for absolute ocular fundus measurement.

Measurements of the human ocular fundus in the three spatial dimensions have not been absolute because measuring techniques have used the optical system of the eye as part of the total ophthalmoscopic system. The ophthalmoscopic magnification due to the total dioptric power of an individual eye can vary substantially from that of the average eye. A new method has been developed to form interference fringes on the fundus so that the fringe spacing can be calculated within a small error by using measured values. The photographed fringes then act as a scale at the fundus with the fringe spacings serving as the graduations, thus allowing accurate absolute measurements of the fundus through the interfering ocular media.

Biometry↗
PubMed1983

The visual evoked potential in glaucoma and ocular hypertension: effects of check size, field size, and stimulation rate.

In order to determine the optimum stimulus conditions for the detection of optic nerve damage due to glaucoma and ocular hypertension, checkerboard pattern reversal visual evoked potentials (VEPs) were recorded from 20 glaucoma patients, 20 ocular hypertensive patients, and 20 age-matched normals. Two check sizes (12' and 48'), two field sizes (14 degrees and 28 degrees), and two alternation rates (1.9 and 7.5 alt/sec) were used. All subjects had visual acuities of 20/40 or better in each eye and equal pupils of 2 to 5 mm diameter. The largest number of VEP abnormalities were found with large checks (48') reversing at a fast rate (7.5 alt/sec). After correcting for the effects of age, visual acuity, and pupil size, 16 of 30 eyes with glaucomatous visual field defects had abnormally long VEP latencies under this condition (beyond the 99% confidence limit of the normal subjects). Nine of 40 ocular hypertensive eyes also had abnormally long latencies. Increased pattern VEP latency was significantly correlated with both the severity and location of visual field defects and the degree of cupping and pallor of the optic disc. VEP latency was not significantly related to intraocular pressure.

Adult↗
PubMed1983

Regional difference in ambient intraluminal gastric acidity after cimetidine monitored by intragastric pH-metry.

Acid secretion was monitored in five duodenal ulcer patients using intragastric glass pH electrodes located in the gastric body and antrum under basal conditions and after the administration of cimetidine. It was shown that differences exist between the body and antral pH in the basal state and in the response to cimetidine. The basal hydrogen ion concentration (mean +/- SEM, mmol/l) in the body, 25.97 +/- 5.03, exceeded that in the antrum, 10.59 +/- 6.44 (p less than 0.05). After cimetidine, the pH rose to 3.5 at both electrodes, this stage being shorter in the antrum (16 min) than body (54 min) (p less than 0.0125). During the next stage the pH rose above 3.5 and the hydrogen ion concentration (mean +/- SEM, mmol/l) was very low in both the body, 0.05 +/- 0.01 (p less than 0.0005 compared to basal) and antrum, 0.08 +/- 0.05 (p less than 0.05 compared to basal). Recovery to basal pH levels occurred more quickly in the body than antrum. Intragastric pH-metry offers a reliable method for studying the mode of action of pharmacological agents on the stomach and contributes information not made available by routine gastric analysis.

Cimetidine↗
PubMed1982

RAST in the diagnostic of dog dander allergy. A comparison between three allergen preparations using two variants of RAST.

The results of the skin, bronchial or conjunctival provocation tests and of the radioallergosorbent test (RAST) with dog dander and hair extract preparations from two different producers were compared. 202 asthmatic children were included in the study. The clinical tests, Al-RAST and paper RAST, were performed using only one allergen preparation (Hu073), while two allergen preparations (e2 and e5) were used in Phadebas RAST. A good correlation was generally found between the results of the clinical diagnostic tests, the clinical history and the results of RAST. Phadebas RAST e2 was the most specific but the least sensitive: it gave a class 0 result in 18% and class 3-4 in 34.5% of the subjects with a positive provocation test. The corresponding numbers for e5 RAST were 6.0% and 70.2%, respectively. Al-RAST was equally sensitive, but had lower specificity than Phadebas RAST e5. The correlation between Phadebas RAST e5 and paper RAST Hu 073 was excellent, which indicates a remarkable similarity between these allergen extracts. Using sensitive, immunochemically standardized Phadebas RAST e5 or Al-RAST methods, classes 0-1 can be regarded as negative, class 2 as doubtful and classes 3-4 as clinically positive results.

Adolescent↗