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Biomedical subjects

M Weiner

Publications and source records attributed to M Weiner.

At least 109 records · Page 6Linked to original sources
PubMed1992

Differential effects of swimming and running on microsomal metabolism in middle-aged and aged Fischer 344 rats.

Cytochrome P-450 (P-450) content as well as p-nitroanisole (pNA) O-demethylase and UDP-glucuronyltransferase (UDPGT) activities were determined in livers of middle-aged (MA; 12 or 18 months) and aged (24-26 months) rats exercised by either treadmill running or swimming. In addition, aniline hydroxylase activity was measured in MA runners and aged swimmers and compared to respective sham and non-handled controls. Treadmill exercise consisted of running aged and MA rats on a motorized treadmill for 16 and 20 m/min respectively, 60 min/day and 4 times per week, for 8 weeks. Sham rats were placed on the treadmill twice per week for 5 min at 8 m/min. No differences were found in any parameter comparing sham rats to non-handled controls. Running did not affect body weight or hepatic microsomal protein during the 8-week study. A 33-35% decline in microsomal P-450 content in treadmill exercised MA and aged rats was found. PNA O-demethylase activity was decreased 30% in MA and 45% in aged runners and aniline metabolism was inhibited 21% in MA rats. UDPGT activity was not affected by running in MA or aged rats. Swimming exercise was accomplished by placing the rats in a tank of water (32-33 degrees C) filled to a depth of 2 ft. Swim time was 60 min twice daily, 5 times per week. The aged and MA rats were trained for 6 months and 1 year, respectively. Two control groups, non-swimming sedentary (dry control) and 1 min swim/day sham (wet control), were utilized. MA and aged wet controls and swimmers weighted 8% and 15% less respectively, than MA and aged sedentary rats. Microsomal protein was significantly increased in MA swimmers compared to sedentary (20%) and wet control (35%) but no change was found with swimming in the aged rats. The results of the enzymatic studies were variable in the MA rats. Increases in P-450 content were found in wet controls (16%) and swimmers (27%) of the MA group, but only the swimming change was significant. No significant change was determined for pNA metabolism between swimmers and wet (22%) or dry (17%) controls. Aged swimmers and wet controls were more consistent, with no change in any of the parameters except aniline metabolism which was significantly increased in wet controls (25%) and swimmers (28%) as compared to dry controls. No significant change in UDPGT activity was measured in either age group of swimmers.(ABSTRACT TRUNCATED AT 400 WORDS)

Aging↗
PubMed1992

The effects of age on the pharmacokinetics and biotransformation of theophylline in vivo and in vitro in the Mongolian gerbil (Meriones unguiculatus).

The effect of post maturational aging on the in vivo disposition of theophylline was examined in the Mongolian gerbils (Meriones unguiculatus) aged 30-39 (old), 12-18 (middle-aged) and 3 (young) months following a 20 mg/kg i.p. dose. Biotransformation of theophylline was also examined in liver microsomes from non-induced and 3-methylcholanthrene induced gerbils. Analysis of theophylline plasma kinetics showed decreased clearance, increased half-life and increased volume of distribution in old vs. young animals. Clearance to the 1,3-dimethyluric acid metabolite was similar for all age groups, while clearance to the 1-methyluric acid metabolite was significantly lower in the middle-aged group compared to that of young and old gerbils. Urinary recovery of 1-methylurate was increased in old vs. young and middle-aged animals while recovery of theophylline was decreased. 3-Methylcholanthrene induction resulted in decreased recovery of theophylline and increased recovery of 1,3-dimethylurate and 1-methylurate in young and middle-aged gerbils compared to non-induced controls. Decreased microsomal protein content was observed in old vs. young and middle-aged gerbils and an age-related decrease in cytochrome P-450 content (nmol P-450/g liver) was also observed. The rate of dimethylurate formation was decreased 37% in microsomes from old vs. young and middle-aged gerbils. 3-Methylcholanthrene administration resulted in a 2- and 1.5-fold increase in the rate of 1,3-dimethylurate formation in young and middle-aged gerbils, respectively. The results of these experiments indicate that the Mongolian gerbil may be useful for the study of the biochemical mechanisms underlying age-related changes in the biotransformation and kinetics of theophylline.

Aging↗
PubMed1992

Thermal effects on horseradish peroxidase uptake in laser nerve transections.

The authors previously reported that rat tibial nerves transected with CO2 or KTP/532 laser transmit less horseradish peroxidase (HRP) than those transected with a scalpel. This may be due to laser-specific effects or to thermal phenomena that are laser-independent. This study investigated potential thermal effects on the transmission of HRP through the tibial branch of the sciatic nerve in rats. Bilateral nerve transections were performed on 18 animals using a scalpel (control) or an electrocautery device, which simulated the thermal effects produced by lasers. HRP retrograde transport and deposition in the rat spinal cord were analyzed. Thirteen of 15 animals showed a higher number of HRP-labelled neurons on the scalpel side compared to the electrocautery side; a paired student's t test showed a significant difference (P = .028) in the numbers of HRP-stained cell bodies between the control group (x = 687.13 +/- 119.3) and the electrocautery group (x = 388.1 +/- 111.2). In conclusion, reduced HRP uptake in tibial nerves transected with lasers may be in part due to thermal effects produced by the lasers.

Animals↗
PubMed1992

Inspiratory muscle training in patients with bronchial asthma.

In patients with asthma, the respiratory muscles have to overcome the increased resistance while they become progressively disadvantaged by hyperinflation. We hypothesized that increasing respiratory muscle strength and endurance with specific inspiratory muscle training (SIMT) would result in improvement in asthma symptoms in patients with asthma. Thirty patients with moderate to severe asthma were recruited into 2 groups; 15 patients received SIMT (group A) and 15 patients were assigned to the control group (group B) and got sham training in a double-blind group-comparative trial. The training was performed using a threshold inspiratory muscle trainer. Subjects of both groups trained five times a week, each session consisted of 1/2-h training, for six months. Inspiratory muscle strength, as expressed by the PImax at RV, increased significantly, from 84.0 +/- 4.3 to 107.0 +/- 4.8 cm H2O (p < 0.0001) and the respiratory muscle endurance, as expressed by the relationship between Pmpeak and PImax from 67.5 +/- 3.1 percent to 93.1 +/- 1.2 percent (p < 0.0001), in patients of group A, but not in patients of group B. This improvement was associated with significant improvements compared with baseline for asthma symptoms (nighttime asthma, p < 0.05; morning tightness, p < 0.05; daytime asthma, p < 0.01; cough, p < 0.005), inhaled B2 usage (p < 0.05), and the number of hospital (p < 0.05) and sick-leave (p < 0.05) days due to asthma. Five patients were able to stop taking oral/IM corticosteroids while on training and one in the placebo group. We conclude that SIMT, for six months, improves the inspiratory muscle strength and endurance, and results in improvement in asthma symptoms, hospitalizations for asthma, emergency department contact, absence from school or work, and medication consumption in patients with asthma.

Adult↗
PubMed1992

A clinical evaluation of the effect of calf blood dialysate on the course of acute myocardial infarction.

The effect of daily intravenous treatment for 3 weeks with a calf blood dialysate presumed to improve disturbed oxidative metabolism was compared with placebo in a randomized double-blind study of 60 subjects with a first acute transmural myocardial infarction. Overall clinical evaluation of initial severity and clinical course suggested a better response of borderline significance in the dialysate-treated group. Blood enzyme elevations were statistically significantly less for that group on day 4 post-infarction for creatine kinase (CK) and aspartate aminotransferase (AspAT) but not for lactate dehydrogenase (LDH). ST segment elevations in the 36 lead ECG developing after admission were fewer in the verum treated than in the placebo group. Results by each of three criteria (clinical evaluation, enzyme elevations, and electrocardiographic changes) suggest a more favorable response to treatment with the calf blood dialysate as compared to placebo.

Actihaemyl↗
PubMed1991

Gallium-67 scans as an adjunct to computed tomography scans for the assessment of a residual mediastinal mass in pediatric patients with Hodgkin's disease. A Pediatric Oncology Group study.

This study determines the utility of gallium-67 (Ga-67) scintigraphs as an adjunct to computed tomography (CT) scans for the assessment of residual mediastinal masses in children and adolescents with advanced-stage Hodgkin's disease. At diagnosis 42 patients with CT scan-documented mediastinal disease had a Ga-67 scan performed. Thirty-four of 42 patients (81%) had gallium-avid mediastinal lesions, whereas in eight (19%), the Ga-67 scan was negative. At the completion of eight cycles of therapy of Mustargen (mechlorethamine), Oncovin (vincristine), procarbazine, prednisone (MOPP) alternating with doxorubicin, bleomycin, vinblastine, dacarbazine (ABVD), 21 of 34 patients with initially positive Ga-67 scans had them repeated; 18 of 21 converted to negative results, and three remained positive. In 11 of 18 patients, the loss of gallium avidity was consistent with a negative mediastinal CT scan. In seven, although the gallium scan was negative, the CT scan remained positive; all seven patients had a mediastinal biopsy of suspected residual disease and in all seven the biopsy results were negative for Hodgkin's disease. These preliminary results in a small cohort of patients demonstrate that Ga-67 scans may be of benefit in evaluating residual mediastinal masses in patients with Hodgkin's disease.

Adolescent↗
PubMed1991

Nature of enhanced mitochondrial oxidative metabolism by a calf blood extract.

The effect of calf blood extract (Solcoseryl, SS) on mitochondrial oxidative function in various states was studied polarographically in vitro. 1) Mitochondrial respiration in all 4 conventional study states (Estabrook, 1967) was enhanced by the addition of SS, including states 1 and 2 (endogenous substrates only). 2) The effect of SS on mitochondrial oxygen consumption was concentration dependent, while ADP/O ratio remained constant. The effect of added respiratory substrates varied with the particular substrate at optimally active concentrations. With suboptimal substrate levels, ADP/O ratios were concentration dependent, in contrast to the SS effect. Under oligomycin ATPase inhibition, SS was no longer active, in contrast to DNP, which remained active. 3) In states 3 (added ADP) and 4 (ADP exhausted), oxygen consumption and oxidative phosphorylation were enhanced by SS in the presence or absence of citrate, glutamate, pyruvate, lactate, or ascorbate. However, in the presence of succinate, SS had no effect. 4) ADP/O ratio was decreased by SS in the presence of added substrate, suggesting that SS activation of H(+)-ATPase enhances ATP hydrolysis as well as oxidative phosphorylation and ATP synthesis. 5) The enhancing effect of SS on mitochondrial function is due to hydrophilic components of SS. The lipidic components obtained by Folch fraction of SS have no effect. It is concluded that the effects of SS respiratory substrates and uncouplers on mitochondrial function are essentially different. SS enhances both ATP synthesis and oxygen consumption by mitochondria.

Actihaemyl↗
PubMed1991

M.H2I, a multispecific 5C-DNA methyltransferase encoded by Bacillus amyloliquefaciens phage H2.

Bacillus amyloliquefaciens phage H2 codes for a multispecific cytosine-5-DNA- methyltransferase (MTase), M.H2I, which methylates GGCC, GCNGC and [sequence: see text] target sequences. The gene coding for M.H2I was cloned in Escherichia coli and its nucleotide (nt) sequence was determined. It consists of 1509 bp, corresponding to a protein of 503 amino acids (aa) with a calculated Mr of 57,166. A comparison of the aa sequence of M.H2I with those of the multispecific MTases encoded by Bacillus subtilis phages SPR, phi 3T and rho 11S, revealed that M.H2I is closely related to these enzymes. A very high degree of homology was observed between M.H2I and M.rho 11SI, with 96.2% aa identity and 97.8% nt identity of the corresponding genes.

Amino Acid Sequence↗
PubMed1991

Chemotherapy of metastatic Merkel cell cancer.

Out of 16 cases of Merkel cell cancer identified in the records of the Mt. Sinai Medical Center or affiliates, 11 patients developed systemic metastases. Literature review confirms the substantial possibility of dissemination. Both in our series and in the literature, cytotoxic chemotherapy produced a high rate of usually short-lived response, although one of our patients with disseminated metastases achieved complete remission for two years.

Adult↗
PubMed1991

An urban primary school health program.

This paper summarizes the results of the first three years of an integrated on-site school health demonstration project based on the family practice model of delivering primary health care. An inner city public elementary school was chosen as the study location. Of the 712 study participants, 98% were black or Hispanic. Prior to implementation of the demonstration project, the Health Guarded Index for the study population was computed to be 58%. Among study participants, this index rose to 79% during the first year of the project and eventually reached 95% during the third year of the project. The absentee rates among study participants relative to nonparticipants decreased to 8.7% during the first year of the project and by 36.2% during the third year of the project. The substantial increase in the Health Guarded Index indicates that, among study participants, preventable defects, such as lack of immunizations, dental care, screening for common problems, and follow-up had been largely corrected. The substantial decline in absenteeism among study participants clearly shows the effectiveness of the demonstration project in promoting good health by decreasing morbidity and/or decreasing recovery time. Overall, the results of the three-year demonstration project reported here show that a carefully designed, well-coordinated school health program based on a family practice model can have a substantially favorable impact on the health of participating children.

Absenteeism↗
PubMed1991

Doppler sonography of the carotid arteries in patients treated by radiation after laryngectomy.

The authors examined by Doppler sonography 86 patients undergoing rehabilitation after being treated for malignant tumor of the larynx by radical surgery and radiotherapy. In 39.5% of the patients pathological results were registered mainly in the extracranial segment of the carotids. Focal neurological deficits were registered only in 3 patients, while all the others were asymptomatic. The correlation between the time elapsed after radiotherapy and the stenotic-occlusive changes registered in the carotids, as well as the effect of hypertension, diabetes and smoking were analysed. The results suggest the influence of ionizing radiation on the occurrence of stenotic-occlusive processes in the neck segment of the carotid arteries. The population of patients examined is considered at risk of stroke.

Aged↗
PubMed1990

Epicardial and endocardial localized 31P magnetic resonance spectroscopy: evidence for metabolic heterogeneity during regional ischemia.

Previous studies have noted that myocardial blood flow and high energy phosphates are heterogeneous across the myocardial wall during ischemia. In order to determine whether differences in metabolites between the subendocardium and subepicardium could be detected using 31P magnetic resonance spectroscopy, the Fourier series window (FSW) experiment was implemented on a porcine model of graded regional ischemia. FSW experiments using a planar phantom showed a 46% improvement in localization to the subendocardium compared to a one-pulse experiment. Animal studies of graded ischemia demonstrated a gradient in the phosphocreatine to inorganic phosphate ratio in the myocardium that paralleled the gradient in blood flow. These studies demonstrate the ability of spatially localized 31P magnetic resonance spectroscopy to detect regional changes in myocardial high energy phosphates localized to the subepicardium and subendocardium.

Animals↗
PubMed1990

Evaluation of analgesic agents in recurring headache compared with other clinical pain models.

The efficacy of three preparations (placebo, analgesic agent, and analgesic plus antihistaminic agent) were compared in a double-blind crossover study in subjects with recurring headaches. It was confirmed that headache as a pain model does not show the usual return of pain with as the effects of a single analgesic dose wear off. Consequently, there is no "peak effect," and the rationale for comparing treatments by "area under the curve" calculations is weakened. Greater efficacy was demonstrated for the analgesic over the placebo and for the analgesic and antihistaminic combined over the analgesic alone in several parameters. Slopes of straight lines derived as a quadratic function of pain versus time data proved to be a more effective discriminator between treatments than area under the curve calculations from the same data.

Acetaminophen↗
PubMed1990

Immigration: perspectives from receiving countries.

The author examines the issue of international migration from the standpoint of receiving countries. He attempts "to understand how and why migrant-receiving countries respond as they do, and to suggest some of the new issues in international migration that arise in a world in which the supply of would-be migrants and refugees is now greater than receiving countries are willing to accept."

Demography↗
PubMed1990

Evaluation of Bacto TB hydrolysis reagent (Tween 80) for the identification of Branhamella catarrhalis.

An investigation of the hydrolysis of Tween 80 reagent by Branhamella catarrhalis and related organisms (Neisseria and Moraxella species) revealed that only B. catarrhalis gave a positive result. A total of 226 strains, including reference organisms and clinical isolates, were studied. B. catarrhalis changed the color of the reagent from amber to pink-red after overnight incubation. We recommend this simple and cost-effective test as an alternative procedure to DNase testing or tributyrin hydrolysis or as a supplemental procedure for the identification of B. catarrhalis in clinical specimens.

Bacteriological Techniques↗
PubMed1990

Age-related changes in biotransformation of azoxymethane and methylazoxymethanol in vitro.

1. Age-related changes in hepatic hydroxylation of azoxymethane (AZO) to methylazoxymethanol (MAM), as well as colonic phase I metabolism of MAM by alcohol dehydrogenase (ADH) were examined in young (2-4 months), middle-aged (12-14 months), and old (22-24 months) male Fischer 344 rats. In addition, the possibility that colonic glucuronyltransferase might be involved in the biotransformation of MAM was also investigated. 2. A significant decrease in hepatic conversion of AZO to MAM was found in old vs young rats, concomitant with a decrease in hepatic cytochrome P-450 content, while no age-related difference was found in the colonic metabolism of MAM by ADH. MAM inhibition of colonic 4-methylumbelliferone glucuronyltransferase was non-competitive, suggesting indirectly that colonic glucuronyltransferase is not involved in conjugation of MAM. 3. It is concluded that ageing in the male Fischer 344 rat results in alternations of AZO and MAM biotransformation which indicate that AZO may be less carcinogenic in older rats.

Aging↗