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Biomedical subjects

Y Cohen

Publications and source records attributed to Y Cohen.

At least 289 records · Page 16Linked to original sources
PubMed1988

Treatment of diffuse histiocytic and diffuse mixed non-Hodgkin lymphomas with cyclophosphamide, doxorubicin, vincristine and prednisone (CHOP).

During 1977 to 1985 90 patients with large-cell non-Hodgkin lymphoma (diffuse histiocytic or diffuse mixed according to Rapport classification) were treated by the CHOP regimen (cyclophosphamide, doxorubicin, vincristine and prednisone) with a mean follow-up of 41 months. Thirty-four patients were treated with radiation therapy as well. The mean number of CHOP cycles to achieve complete response was 4.0 and the mean total number of cycles was 6.6. For 78 patients it was possible to calculate relative dose intensity (RDI) for each drug and the average RDI. Sixty-four patients (71%) achieved CR. The actuarial 5-year survival rate of all patients was 52%. The median RDI for cyclophosphamide was 0.72, for doxorubicin 0.70, for vincristine 0.69 and the median average RDI was 0.69. The following favorable prognostic factors were found to be of statistical significance: female sex and stages I-III as compared to stage IV. The 5-year survival rate for stage I & II patients treated by CHOP plus radiotherapy was 70% as compared to 55% for those treated by CHOP only; this difference was not statistically significant.

Adolescent↗
PubMed1987

Prognostic significance of plasma cell morphology in multiple myeloma.

The effect of bone marrow plasma cell morphology at diagnosis on survival time was evaluated in 139 patients with multiple myeloma. According to the morphological classification scheme the patients were categorized as mature (30 patients), immature (76 patients) or plasmablastic (33 patients). The plasmablastic group had an estimated median survival (Kaplan-Meier method) of 10.9 months, compared with 32.2 months for immature and 60 months for mature types (P = 0.0000). The prognostic value of a morphologic classification in multiple myeloma was further demonstrated by means of a multivariate linear regression analysis of survival data. Expected survival was calculated using clinical features and morphologic subtypes. The estimated survival time for plasmablastic myeloma was shorter by 51.4 months and for immature myeloma patients by 35 months, compared with mature myeloma patients with similar clinical characteristics. Plasma cell morphology at diagnosis is an important predictor of survival duration in patients with multiple myeloma.

Bone Marrow↗
PubMed1987

Multidrug chemotherapy using bleomycin, methotrexate, and cisplatin combined with radical radiotherapy in advanced head and neck cancer.

Thirty-one patients with Stage III-IV head and neck squamous cell cancer were treated by three courses of combination chemotherapy using bleomycin, methotrexate, and cisplatin followed by a radical course of radiation and in two cases by surgery. Of 29 evaluable patients, 4 (14%) achieved complete remission (CR) with chemotherapy and 13 (45%) had a partial response (PR). With the addition of radiotherapy and surgery, the CR rate increased to 72%. At 30 months the actuarial survival of all evaluable patients was 61% and of complete responders, 76%. Patients with nasopharyngeal cancer had an actuarial survival of 80% at 30 months, whereas patients with squamous malignancies at other sites in the head and neck region had an actuarial survival of only 37%. Side effects were tolerable. It is concluded that complete responders to combination chemotherapy and radiotherapy have a survival benefit at 30 months. The combined approach is most effective in nasopharyngeal cancer.

Actuarial Analysis↗
PubMed1987

Association of a new type of gliding, filamentous, purple phototrophic bacterium inside bundles of Microcoleus chthonoplastes in hypersaline cyanobacterial mats.

An unidentified filamentous purple bacterium, probably belonging to a new genus or even a new family, is found in close association with the filamentous, mat-forming cyanobacterium Microcoleus chthonoplastes in a hypersaline pond at Guerrero Negro, Baja California Sur, Mexico, and in Solar Lake, Sinai, Egypt. This organism is a gliding, segmented trichome, 0.8-0.9 micrometer wide. It contains intracytoplasmic stacked lamellae which are perpendicular and obliquely oriented to the cell wall, similar to those described for the purple sulfur bacteria Ectothiorhodospira. These bacteria are found inside the cyanobacterial bundle, enclosed by the cyanobacterial sheath. Detailed transmission electron microscopical analyses carried out in horizontal sections of the upper 1.5 mm of the cyanobacterial mat show this cyanobacterial-purple bacterial association at depths of 300-1200 micrometers, corresponding to the zone below that of maximal oxygenic photosynthesis. Sharp gradients of oxygen and sulfide are established during the day at this microzone in the two cyanobacterial mats studied. The close association, the distribution pattern of this association and preliminary physiological experiments suggest a co-metabolism of sulfur by the two-membered community. This probable new genus of purple bacteria may also grow photoheterotrophically using organic carbon excreted by the cyanobacterium. Since the chemical gradients in the entire photic zone fluctuate widely in a diurnal cycle, both types of metabolism probably take place. During the morning and afternoon, sulfide migrates up to the photic zone allowing photoautotrophic metabolism with sulfide as the electron donor. During the day the photic zone is highly oxygenated and the purple bacteria may either use oxidized species of sulfur such as elemental sulfur and thiosulfate in the photoautotrophic mode or grow photoheterotrophically using organic carbon excreted by M. chthonoplastes. The new type of filamentous purple sulfur bacteria is not available yet in pure culture, and its taxonomical position cannot be fully established. This organism is suggested to be a new type of gliding, filamentous, purple phototroph.

Actin Cytoskeleton↗
PubMed1987

Cholecystokinin and bombesin in vagotomized or intact lean and obese rats: effects on neurotransmitters in brain.

Cholecystokinin (CCK) and Bombesin (BBS) are two neuropeptides which induce changes in monoamines in the brain after peripheral administration. A vagal mediation of these effects was investigated since the satiety responses to both peptides are affected differently by vagotomy. This work was performed on genetically obese and lean Zucker rats and on "cafeteria-fed" and lean Sprague-Dawley rats as the effects of the peptides are dissimilar in these different groups. Vagotomy either inhibited or potentiated the peptide-induced effects, or created new variations. With CCK, the inhibition occurred mainly in the serotonergic system and in the Zucker strain, while new effects appeared in the dopaminergic system of lean rats of both strains. With bombesin, vagotomy inhibited the effects in the dopaminergic system in all lean rats, while new effects were observed in the serotonergic system in the Zucker strain. These data enable the differentiation of the mechanisms of action of both peptides and their selective effects, according to the strain of rat and the presence or absence of obesity.

Animals↗
PubMed1987

Tissue distribution of acebutolol in mature normotensive and stroke-prone spontaneously hypertensive rats.

Tissue distribution of acebutolol was studied in 33-week-old normotensive (WKY) and Okamoto stroke-prone (SHR-SP) rats, 30 min after an i.v. administration, by using 14C-acebutolol. Plasma level of acebutolol was higher in WKY than in SHR-SP. Aorta, kidney, liver and muscle radioactivity/plasma radioactivity ratios were higher in SHR-SP than in WKY. The brain/plasma radioactivity ratio was very low and similar in the two groups. The drug distribution was the same in the two groups except in medulla + corpus trapezoides where drug concentration was greater in SHR-SP. These results, compared with previous ones, show an age-related evolution in pathological state in SHR-SP. They point out a specific concentration of the beta-blocking drug in a defined part of the brain, namely medulla + corpus trapezoides.

Acebutolol↗
PubMed1987

Photosynthetic action spectra and adaptation to spectral light distribution in a benthic cyanobacterial mat.

We studied adaptation to spectral light distribution in undisturbed benthic communities of cyanobacterial mats growing in hypersaline ponds at Guerrero Negro, Baja California, Mexico. Microscale measurements of oxygen photosynthesis and action spectra were performed with microelectrodes; spectral radiance was measured with fiber-optic microprobes. The spatial resolution of all measurements was 0.1 mm, and the spectral resolution was 10 to 15 nm. Light attenuation spectra showed absorption predominantly by chlorophyll a (Chl a) (430 and 670 nm), phycocyanin (620 nm), and carotenoids (440 to 500 nm). Blue light (450 nm) was attenuated 10-fold more strongly than red light (600 nm). The action spectra of the surface film of diatoms accordingly showed activity over the whole spectrum, with maxima for Chl a and carotenoids. The underlying dense Microcoleus population showed almost exclusively activity dependent upon light harvesting by phycobilins at 550 to 660 nm. Maximum activity was at 580 and 650 nm, indicating absorption by phycoerythrin and phycocyanin as well as by allophycocyanin. Very little Chl a-dependent activity could be detected in the cyanobacterial action spectrum, even with additional 600-nm light to excite photosystem II. The depth distribution of photosynthesis showed detectable activity down to a depth of 0.8 to 2.5 mm, where the downwelling radiant flux at 600 nm was reduced to 0.2 to 0.6% of the surface flux.

Adaptation, Physiological↗
PubMed1987

Sulfur metabolism in Beggiatoa alba.

The metabolism of sulfide, sulfur, and acetate by Beggiatoa alba was investigated under oxic and anoxic conditions. B. alba oxidized acetate to carbon dioxide with the stoichiometric reduction of oxygen to water. In vivo acetate oxidation was suppressed by sulfide and by several classic respiratory inhibitors, including dibromothymoquinone, an inhibitor specific for ubiquinones. B. alba also carried out an oxygen-dependent conversion of sulfide to sulfur, a reaction that was inhibited by several electron transport inhibitors but not by dibromothymoquinone, indicating that the electrons released from sulfide oxidation were shuttled to oxygen without the involvement of ubiquinones. Intracellular sulfur stored by B. alba was not oxidized to sulfate or converted to an external soluble form under aerobic conditions. On the other hand, sulfur stored by filaments of Thiothrix nivea was oxidized to extracellular soluble oxidation products, including sulfate. Sulfur stored by filaments of B. alba, however, was reduced to sulfide under short-term anoxic conditions. This anaerobic reduction of sulfur was linked to the endogenous oxidation of stored carbon and to hydrogen oxidation.

Acetates↗
PubMed1987

Treatment of advanced gastric cancer with DDP (cisplatin), adriamycin, and 5-fluorouracil (DAF).

Sixteen evaluable patients with advanced gastric cancer who had no prior therapy were treated intravenously with cisplatin (DDP) 20 mg/m2/day on days 1-5 and with Adriamycin 40 mg/m2 and 5-fluorouracil 600 mg/m2 on day 1 (DAF) every 3 weeks. There were five objective partial responses, giving a response rate of 31%. Five patients had minor responses, and 5 others achieved disease stabilization. The median duration of response for responders was 10 months, and the median time to tumor progression in nonresponders was 6 months. The overall median survival was 12 months (responders 14 months, nonresponders 9 months; NS). Most patients had a subjective improvement, including disappearance of abdominal pain (7/9) and gastrointestinal bleeding (5/7). The drug toxicity was moderate to severe. The primary nonhematologic toxicities were nausea and vomiting (in all patients), severe weakness (44%), and parasthesias (31%). Eight patients (50%) experienced significant bone marrow suppression. The DAF combination appears to have some activity in patients with advanced gastric cancer. However, further efforts in new drug development and other combinations are needed to improve the results of chemotherapy in stomach cancer.

Adenocarcinoma↗
PubMed1987

Changes in brain monoamine content and metabolism induced by paraoxon and soman intoxication. Effect of atropine.

1. Soman induced a decrease in hypothalamic, hippocampal and cortical noradrenaline, an increase in hippocampal and cortical dopamine and an increase in hypothalamic serotonin while paraoxon did not modify these neurotransmitter concentrations. The increases in 3,4-dihydroxyphenylacetic acid, homovanillic acid and 5-hydroxyindole acetic acid produced by the two drugs witness an accelerated turnover of dopamine and serotonin. 2. Atropine pretreatment completely antagonized the paraoxon-induced changes but only partially suppressed the soman-induced modifications. 3. These data suggest that soman produces a direct effect on monoamine metabolism which is not related to acetylcholine accumulation.

Animals↗
PubMed1987

[Not Available].

Explore the source record for details and available documents.

Canada↗
PubMed1987

[Autonomic cardiovascular regulation and permanent catheterization in normotensive conscious (WKY) and spontaneously hypertensive (SHR) rats].

In cardiovascular research, methods of indwelling catheterism have been frequently described. In the present work, we used normotensive and SHR rats to compare carotid catheterism to left ventricular catheterism, this last method being proposed by some investigators for cardiac index measurement. Our results of plasma catecholamines and autonomous nervous system activity show that ventricular catheterism results in an important disturb in cardiovascular regulation and question its validity to study cardiac function.

Acetylcholine↗
PubMed1987

Peripheral and central cardiovascular effects of ketanserin in conscious normotensive rats.

The aim of the present study was to evaluate the effects of low doses of ketanserin, close to therapeutic ones, in conscious normotensive rats and to compare the different thresholds of 5-HT2- and alpha-antagonist properties and central sympatho-inhibitory activity. Male Sprague-Dawley rats (250-300 g) were used. Fourty-eight hr before experimentation, indwelling venous and arterial catheters were placed in each rat under light anaesthesia, and exteriorized through the interscapular skin. Drugs injected by i.v. route were ketanserin (50, 100, 200 micrograms/kg), serotonin (50 micrograms/kg), noradrenaline (1 microgram/kg), angiotensin (0.5 microgram/kg), nitroglycerin (200 micrograms/kg) and histamine (100 micrograms/kg). Ketanserin induced a short-lasting reduction in blood pressure and did not modify heart rate. At the dose of 50 micrograms/kg, this compound fully inhibited the pressor effect of serotonin, without modifying its hypotensive responses; after 200 micrograms/kg, ketanserin reduced by 50% the pressor effect of noradrenaline. Comparison of antagonistic activities on phenylephrine and noradrenaline pressor responses showed a selective blockade of alpha 1-adrenoceptors by 100 micrograms/kg ketanserin. In contrast, the angiotensin hypertensive response was unchanged. Reflex bradycardia after noradrenaline and angiotensin was reduced by 100 micrograms/kg ketanserin, whereas nitroglycerin and histamine effects were unaffected. In conclusion, administration of increasing low doses of ketanserin showed that blockade of 5-HT2-receptors appears in first, then a central sympatho-inhibitory effect and a selective alpha 1-adrenolytic activity occur. In addition, baroreceptor sensitivity seems not to be affected.

Angiotensin II↗
PubMed1986

Non-Hodgkin's lymphoma presenting with spinal epidural involvement.

Cord compression was noted at presentation in 10 of 453 (2.2%) previously untreated non-Hodgkin's lymphoma patients seen at the Northern Israel Oncology Center between 1968 and 1983. A prodromal phase of local back pain occurred in eight patients, persisting up to 1 year, followed by a second phase of rapidly progressive signs of cord compression. Five of the ten patients presented with primary spinal epidural involvement (Stage IE), whereas the others had Stage IIE and IIIE (one patient each) and Stage IV, with bone and bone marrow involvement (three patients). All patients had unfavorable histologic diagnoses, mostly of the intermediate grade malignancy types according to the Working Formulation. The patients were treated by radiotherapy (two patients), chemotherapy (three patients), or both modalities (five patients). Seven of the ten patients achieved complete remission, but four of them have subsequently had relapses (two patients in bone, one in central nervous system, and one in mediastinum). The 5-year actuarial survival and 3-year relapse-free survival were 66% and 32%, respectively. Median survival has not been reached after a mean follow-up of 34 months. Non-Hodgkin's lymphoma with spinal epidural involvement at presentation is an aggressive disease. An intensive treatment combining irradiation with chemotherapy, and surgery as needed, is suggested in order to achieve good local response and long-term survival.

Actuarial Analysis↗
PubMed1986

The treatment of nonseminomatous testicular tumors: 15 years experience.

Thirty-two patients with nonseminomatous germ cell tumors of the testis were treated at the Northern Israel Oncology Center during the years 1968-1983. The patients were divided into two groups. Group I included 18 patients treated from 1968 to 1976; in group II there were 14 patients treated with combination therapy containing cis-platinum in the years 1977 to 1983. The actuarial survival rate at 38 months from diagnosis is 47% in group I patients and 86% in group II patients. The development of modern radiological techniques, biochemical markers for accurate staging, and the use of cis-platinum-containing combination chemotherapy made this disease curable. New treatment modalities are needed for patients with bulky disease at presentation.

Adolescent↗