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Biomedical subjects

R Cohen

Publications and source records attributed to R Cohen.

At least 415 records · Page 23Linked to original sources
PubMed1988

Plasma alpha-subunit levels during the treatment of pituitary adenomas with the somatostatin analog (SMS 201-995).

The effect os SMS 201-995 (Sandostatin), a long-acting somatostatin analog, on different types of pituitary adenomas including alpha-subunit elevation is illustrated in this report. Treatment induced a fall in hCG levels in a woman with a pituitary adenoma producing only alpha-subunit. In 3 acromegalic patients, there was only a partial drop in GH and alpha-hCG. The same effect was observed in a woman with menopausal FSH and LH levels. SMS reduced plasma TSH and alpha-hCG in a case of thyrotropic adenoma. Two patients exhibiting FSH- and alpha-hCG-secreting adenomas did not respond to acute administration of SMS 201-995. More patients have to be treated before a definitive statement can be made on the usefulness of somatostatin analogs in the management of different types of pituitary adenomas.

Adenoma↗
PubMed1988

Heterogeneity of soluble suppressor factors in rat malignant ascites.

A study was undertaken to enumerate and partially characterize soluble factors generated by tumor-bearing animals capable of suppressing PHA-induced splenocyte proliferation. Sprague-Dawley rats were induced to form malignant ascites by the intraperitoneal injection of the Walker 256 carcinoma. Intact ascites suppressed splenocyte proliferation by 96%. Molecular sieving of the ascites by means of ultrafiltration (10-kilodalton particle cutoff) revealed suppressor activity to reside in both the ultrafiltrate and retentate. Further enumeration of suppressor factors was achieved by preparative polyacrylamide gel electrophoresis of the ascites ultrafiltrate and retentate. Five discrete bands of suppressor activity were resolved in the ultrafiltrate, three of which were heat-labile. Three discrete bands of suppressor activity were resolved in the retentate, none of which were heat-labile. This study underscores the complexity and heterogeneity of soluble factors elaborated in a cancer-bearing animal.

Animals↗
PubMed1988

Use of routine chest radiography in the evaluation of fever in neutropenic pediatric oncology patients.

Evaluation of febrile episodes in children who have become neutropenic during treatment for malignant disease has traditionally included radiography of the chest. It has been our impression that the yield of such examination is low. To test this hypothesis we reviewed all chest radiographs (CXRs) obtained in the above setting in our institution over the last 3 years. These radiographs were independently reviewed by two of us (R.C., J.F.). Sixty-one patients experienced 134 febrile neutropenic episodes for which a CXR was obtained. Only eight (6%) of these films revealed any abnormality. After careful review it was apparent that four of these radiographs did not represent a infectious process. Thus only four of 134 films (2.9%) indicated pulmonary infection as the probable cause of fever in the patient. All four of these patients had prominent respiratory signs or symptoms. Of patients who were febrile but without pulmonary signs/symptoms, only one of 49 had an abnormal radiograph. We feel that such a low yield (at most 2%) calls into question the routine practice of obtaining a CXR in the febrile neutropenic child who is otherwise asymptomatic.

Adolescent↗
PubMed1988

Late results of surgery for congenital esotropia.

In a retrospective study we have evaluated the surgical outcome in 46 children with congenital esotropia who were followed up for at least two years. The results support the concept of early operation for congenital esotropia. Evaluation of the effect of simultaneous weakening of the inferior obliques proved statistically that this reduced the effect of recession-resection of the horizontal recti.

Child, Preschool↗
PubMed1988

Late results of surgery for congenital esotropia.

In a retrospective study we evaluated the surgical outcome in 46 children with congenital estropia who were followed up for at least two years. The results support the concept of early operation for congenital estropia. Evaluation of the effect of simultaneous weakening of the inferior obliques proved statistically that this reduced the effect of recession-resection of the horizontal recti.

Age Factors↗
PubMed1988

[Contribution of bactericidal rate in the initial treatment of severe staphylococcal infections in children].

Rapid bactericidal effect is essential for therapy of severe Staphylococcus aureus infections in children. The in vitro activity of clinically achievable levels of vancomycin and its combinations with gentamicin, amikacin and rifampin plus amikacin was studied with the time-kill curve method at 2.5, 4, 6, 24 and 48 hours against 20 strains of Staphylococcus aureus isolated from children with severe staphylococcal infection. Vancomycin alone exerted a bactericidal effect at 48 hours. However, with the combinations vancomycin plus gentamicin, vancomycin plus amikacin and vancomycin plus amikacin plus rifampin a bactericidal effect was respectively observed at 24, 6 and 4 hours. Most rapid killing was achieved with vancomycin plus rifampin plus amikacin. Thus this antibiotic combination seems the most appropriate for initial treatment of severe staphylococcal infections in children.

Anti-Bacterial Agents↗
PubMed1988

Potentiation of aminoglycoside nephrotoxicity by vitamin-D-induced hypercalcemia.

The effect of 1,25(OH)2 vitamin D3-induced hypercalcemia on the course of aminoglycoside nephrotoxicity in the rat was studied. Daily gentamicin, 100 mg/kg body weight, was administered subcutaneously concomitant with 1,25(OH)2 vitamin D3, 50 ng s.c. to male Sprague-Dawley rats. This group was compared to rats injected with gentamicin alone, 1,25(OH)2 vitamin D3 alone, and an ethanol vehicle as a control. Structural and functional parameters of acute renal failure were assessed following 4, 6 and 7 days of treatment. Severe morphologic evidence of tubular injury was documented on day 6 in the group injected with gentamicin and 1,25(OH)2 vitamin D3. Correlative functional and metabolic evidence of tubular cell deterioration occurred in this group on day 7 as represented by an elevated blood urea nitrogen (BUN), 198 +/- 14 mg/dl (p less than 0.001 compared to all other groups), a heightened mean renal cortical homogenate calcium, 1,028.3 +/- 304.8 nmol/mg protein (p less than 0.05 or better compared to all other groups), and significantly increased mean cortical mitochondrial calcium content, 796.3 +/- 116.5 nmol/mg protein (p less than 0.01 in relation to all other groups). Elevated total serum calcium to a level of 11.9 +/- 0.2 mg/dl (p less than 0.001 compared to control group) developed in the gentamicin/1,25(OH)2 vitamin D3 group on day 4, 2 days prior to pronounced structural damage, and continued to be elevated through day 7. No difference in serum phosphorus levels, however, developed between control and gentamicin-plus-vitamin-D-treated animals except on day 7 when severe renal failure developed in this group.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1987

Characterization of lactogen receptors in lactogenic hormone-dependent and independent NB2 lymphoma cell lines.

A comparative study of lactogen receptors in lactogenic hormone-dependent (Nb2-11C) and independent (Nb2-SP) rat lymphoma cell lines revealed no significant differences in their binding and structural characteristics. The affinity for human growth hormone (hGH) and ovine prolactin is identical (Kd = 1.3 X 10(-10) M). Exposure to hGH results in a rapid receptor down-regulation. This process is faster in Nb2-SP cells, however, similar receptor levels are reached within 3 h. Affinity labeling revealed 2 major binding species (Mr 75,000 and 29,000) in both cell lines. These observations suggest that the spontaneous proliferation of Nb2-SP cells probably results from an aberration in some post-receptoral event of the mitogenic pathway.

Animals↗
PubMed1987

Functional analysis of mononuclear cells infiltrating into tumors: lysis of autologous human tumor cells by cultured infiltrating lymphocytes.

Lymphocytes separated from surgically resected tumor tissue, uninvolved lung tissue, and peripheral blood of lung cancer patients were investigated for cytotoxic potential and analyzed for their phenotypes at the time of surgery and after having been propagated for 4 to 5 wk in the presence of interleukin-2. Most of the tumor lymphocyte infiltrates examined were shown to have a shift in favor of T8 subsets from those found in peripheral blood. No natural killer activity and low cytotoxicity against the autologous tumor were found to characterize the tumor-derived lymphocyte population. Propagation of lymphocytes from the different tissues of the cancer patient in the presence of interleukin-2 preparation induced widespread lytic activity against K562 cells, autologous and allogeneic tumors, but not autologous normal lung or lymphoblasts. However, cytotoxic activity against autologous tumor cells exerted by cultured tumor-infiltrating lymphocytes was found to be significantly higher than the activity of cultured lymphocytes isolated from peripheral blood or uninvolved lung tissue of the same patient. The elevated lytic activity of cells derived from the tumor tissue indicates the accumulation at the tumor site of precursors of natural killer-like cells and specifically stimulated antitumor effectors. Our results suggest the coexistence of two types of anti-autotumor cytotoxic lymphocytes at the tumor site: natural killer-like and specific cytotoxic T-cells.

Aged↗
PubMed1987

Recognition of random shapes in brain-damaged patients.

In two experiments the hypothesis was tested that left hemisphere-damaged patients and especially those with aphasia are impaired in the recognition of meaningless random shapes because they fail to attribute a meaning to the shapes. In a multiple choice recognition task, left hemisphere-damaged patients with aphasia and left and right hemisphere-damaged patients without aphasia were shown complex random shapes together with either a pictorial cue (experiment I and II) or a dotted drawing of its outline on which more or less outstanding parts were specially marked (experiment I). In experiment I no difference between conditions or groups emerged. In experiment II aphasics and left hemisphere-damaged patients without aphasia were generally inferior to right hemisphere-damaged controls and performed significantly better when a pictorial cue was given than when it was absent, however only when the conditions were given in a certain order.

Adolescent↗
PubMed1987

Pharmacokinetics of human growth hormone releasing factor (hGRF-44 NH2) in normal men after intravenous administration of a large range of doses.

Three ranges of doses of growth hormone releasing factor (2.5-80 micrograms, 80-320 micrograms and 75-600 micrograms) were intravenously administered to healthy young volunteers in three double blind studies. Serum circulating GRF levels were determined by radioimmunoassay. Experimental concentration curves were fitted, using the extended least squares method, to a biexponential model for the structural model and power function for the variance model. The power variance model, compared to the constant variance model greatly reduced the coefficient of variation of the biexponential parameters. The power of the variance model was estimated to be 1.95. The distribution half-life was 6.6 min and the elimination half-life was 39.0 min (harmonic means). Total clearance was 0.12 +/- 0.01 microgram/l/min. No difference between these parameters was found for the various doses. GRF kinetics was linear established in the range 10 to 600 micrograms which means that elimination was not altered by the increased doses.

Adult↗
PubMed1987

Glucose utilization in the temporal cortex of affectively ill patients: positron emission tomography.

As temporal lobe dysfunction has been postulated in the affective disorders, the authors investigated glucose utilization in the temporal lobes of 13 affectively ill patients in comparison with 18 normal volunteer controls and 17 previously reported schizophrenic patients, following injections of fluorine 18-2-deoxy-D-glucose (FDG) during somatosensory stimulation to the right forearm. Using a boundary-finding algorithm to outline each temporal lobe, maximum glucose use relative to maximums elsewhere in the same positron emission tomography (PET) slice were calculated. In a small group of moderately to severely depressed patients, this relative measure was significantly reduced in the right (with a similar trend in the left) temporal lobe compared to normal volunteers and the other comparison groups. The lack of a significant increase in glucose utilization, measured either as a maximum or in relation to other areas in the PET scan slice, suggests that a temporal lobe activation or a seizure-like process is not generally occurring during active depressive phases of the illness.

Affective Disorders, Psychotic↗