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Biomedical subjects

A Tenenbaum

Publications and source records attributed to A Tenenbaum.

At least 73 records · Page 4Linked to original sources
PubMed1996

Absence of coronary calcification on double-helical CT scans: predictor of angiographically normal coronary arteries in elderly women?

PURPOSE: To test the hypothesis that angiographically normal coronary arteries in elderly women are identifiable by the absence of coronary calcification on double-helical computed tomographic (CT) scans. MATERIALS AND METHODS: Forty-eight consecutive women (age range, 60-76 years) underwent coronary angiography for chest pain evaluation, as well as double-helical CT. Thirty women (mean age, 65 years +/- 5) had coronary artery disease (CAD), defined as any angiographic disease, and 18 women (mean age, 66 years +/- 4) had angiographically normal coronary arteries. RESULTS: Women with angiographically normal coronary arteries had lower coronary calcification scores than those of patients with CAD: 5.7 +/- 11 versus 580 +/- 634, respectively (P = .0004). Seven women with angiographically normal coronary arteries demonstrated mild coronary calcification (score < 50). Of the 11 women without coronary calcification, none had CAD. Thus, the absence of coronary calcification on double-helical CT scans in elderly women was predictive of angiographically normal coronary arteries with 61% sensitivity, 100% specificity, and 85% accuracy. CONCLUSION: Double-helical CT is an accurate, noninvasive modality for diagnosing angiographically normal coronary arteries in elderly symptomatic women.

Aged↗
PubMed1995

Improved posterobasal segment function after thrombolysis is associated with decreased incidence of significant mitral regurgitation in a first inferior myocardial infarction.

OBJECTIVES: This study was designed to investigate the association between wall motion abnormalities and the occurrence of ischemic mitral regurgitation in patients with a first inferior or posterior myocardial infarction and to reassess the role of thrombolytic treatment in these patients. BACKGROUND: We previously demonstrated that thrombolytic therapy reduces the incidence of significant mitral regurgitation in patients with a first inferior myocardial infarction, but the mechanisms responsible for this decrease were not clear. METHODS: Wall motion score on two-dimensional echocardiography (16 segments) and mitral regurgitation grade (0 to 3) on Doppler color flow imaging were assessed in 95 patients (in 47 after thrombolysis) at 24 h, 7 to 10 days and 1 month after myocardial infarction. Significant mitral regurgitation was defined as moderate or severe (grade 2 or 3). RESULTS: Multivariate analysis revealed that the presence of an advanced wall motion abnormality of the posterobasal segment of the left ventricle was the most significant independent variable associated with significant mitral regurgitation: odds ratio (OR) 15.0, 90% confidence interval (CI) 1.4 to 165.6 at 24 h; OR 2.8, CI 0.9 to 9.3 at 7 to 10 days; OR 4.2, CI 1.2 to 11.4 at 1 month. Thrombolysis reduced the prevalence of advanced wall motion abnormalities in the posterobasal segment at 24 h (55% vs. 75%, OR 0.5, CI 0.2 to 0.99), 7 to 10 days (44% vs. 73%, OR 0.3, CI 0.1 to 0.7) and 1 month (36% vs. 56%, OR 0.4, CI 0.2 to 0.9). CONCLUSIONS: There is a strong association between advanced wall motion abnormalities in the posterobasal segment and significant mitral regurgitation. In this study group, thrombolysis reduced the prevalence of advanced wall motion abnormalities in the posterobasal segment and thereby reduced the incidence of significant mitral regurgitation.

Echocardiography↗
PubMed1994

Generic modelling of cooperative growth patterns in bacterial colonies.

Bacterial colonies must often cope with unfavourable environmental conditions. To do so, they have developed sophisticated modes of cooperative behaviour. It has been found that such behaviour can cause bacterial colonies to exhibit complex growth patterns similar to those observed during non-equilibrium growth processes in non-living systems; some of the qualitative features of the latter may be invoked to account for the complex patterns of bacterial growth. Here we show that a simple model of bacterial growth can reproduce the salient features of the observed growth patterns. The model incorporates random walkers, representing aggregates of bacteria, which move in response to gradients in nutrient concentration and communicate with each other by means of chemotactic 'feedback'. These simple features allow the colony to respond efficiently to adverse growth conditions, and generate self-organization over a wide range of length scales.

Bacteria↗
PubMed1992

Differential PGE2 and cAMP production by allogeneic and syngeneic pregnant mice uteri.

Prostaglandin E2 (PGE2) and cAMP production in allogeneic and syngeneic pregnant mice uteri, were measured in relation to the ratio of plasma estrogen/progesterone levels. PGE2 generation by allopregnant uteri varied with the days of pregnancy. The increment of the prostanoid coincided with the increase in plasma estrogen concentration, whereas the decrement of its production was in parallel with the increment of plasma progesterone. The syngeneic pregnant uterus was unable to increase the release of PGE2 above basal values during the whole pregnancy. The rise of PGE2 production by the allogeneic pregnant uterus was correlated with an increase in cAMP levels. It is proposed that the pregnant mouse uterus increases its ability to release PGE2 in response to an ovarian steroids.

Animals↗
PubMed1991

Effects of sexual steroid hormones on the functionality of murine peritoneal macrophages.

In the present work, we studied the possible effect of steroid hormones, estradiol, progesterone, and 5 alpha-dihydrotestosterone, on different phenotypic and functional characteristics of peritoneal adherent mononuclear cells. We used female and male mice of Balb/c strain, normal, gonadectomized, and gonadectomized with hormonal replacement. We found that gonadectomy in both sexes produced a significant decrease in the functionality of membrane receptors for the complement and in phagocytic activity of Candida albicans-anti-C albicans system. In addition, the percentages of cells that reduced nitroblue tetrazolium were diminished in castrated animals. Ovariectomized females injected with estradiol presented normal levels of phagocytic and metabolic capacities, but the expression of membrane receptors for complement remained decreased. In contrast, progesterone treatment of ovariectomized animals had the opposite effect. Simultaneous treatment with estradiol plus progesterone gave results similar to those observed with estradiol only. Dihydrotestosterone per se did not affect any of the parameters measured in the conditions used here. These results suggest that female steroids affect macrophage functionality, probably by regulating surface receptors that are involved in phagocytic activity.

Animals↗
PubMed1990

Beneficial effect of hepatic arterialization on hypogonadism in male rats with portacaval shunt.

The effect of portacaval shunt (PCS) with and without hepatic arterialization (HA) upon the liver morphology, hemodynamics, and in relation to testicular weight, histology, and plasma sex steroid levels has been investigated in male rats. PCS rats showed a significant decrease in hepatic blood flow, body and liver weights, together with signs of severe hypogonadism. In contrast, in HA rats the increment in liver blood flow was associated with higher body and liver weights. In spite of total portal blood shunting, a beneficial effect on testicular morphology and an increase in plasma testosterone level were observed. In respect to plasma estradiol levels the intergroup differences could not be evaluated due to large individual variations. This was probably caused by the presence of cross-reactive plasma component(s) masking the level of endogenous estrogen. It is concluded that portosystemic shunting is not of primary importance in the etiology of PCS-related hypogonadism in the male.

Animals↗
PubMed1989

[Evaluation of the interleukin 1 production by adherent cells in patients with diabetes type II].

We have studied the comitogenic activity of IL 1 produced by cultures of mononuclear adherent cells obtained from Diabetes Mellitus (DM) type II or non insulin dependent diabetic patients. This activity was measured by the incorporation of 3H Thymidine into cultures of C3H/HeJ mice thymocytes in the presence of phytohemagglutinin (PHA). We have observed that IL 1 from patients with DM type II did not produce a synergistic effect with PHA, since the lymphoproliferation levels were similar to those obtained in the absence of this lectin. This lack of comitogenic activity (P less than 0.001) in relation to the response obtained with IL 1 from normal subjects plus PHA, could be due to the release of one or several soluble substances capable of blocking glycosylated receptors to mitogens or of impairing the cellular activation process.

Adult↗
PubMed1987

Histamine stimulates progesterone synthesis and cyclic adenosine 3',5'-monophosphate accumulation in isolated preovulatory rat follicles.

The effect of histamine on progesterone synthesis and cyclic adenosine 3',5'-monophosphate (cAMP) accumulation was studied in superfused and incubated follicles dissected free from immature rats treated with pregnant mare serum gonadotrophin (PMSG). Histamine, like LH, increased the progesterone synthesis, but to a smaller extent. The H2-antagonist, cimetidine, inhibited completely the histamine-induced progesterone increase while the H1-antagonist, pyrilamine, as well as propranolol and atropine did not affect the initial response but modified its duration. The specific H2-agonist, 4-methylhistamine, but not the H1-agonist, 2-methylhistamine, mimicked the effect of histamine on progesterone synthesis. In the presence of the phosphodiesterase inhibitor, IBMX, histamine increased tissue levels of cAMP. These results suggest that histamine stimulates progesterone synthesis via the H2-receptor with cAMP acting as secondary intracellular messenger.

1-Methyl-3-isobutylxanthine↗
PubMed1985

Structural and functional changes in ovaries from adult mice treated with diethylstilboestrol in the neonatal period.

Ovaries from 8-week-old female NMRI mice in different stages of the oestrous cycle, or from females neonatally treated with the synthetic oestrogen diethylstilboestrol (DES; 5-10(-6) micrograms daily for 5 days), were studied histologically and for the ability to synthesize steroids from [3H]pregnenolone in vitro. Daily doses of 10(-4) micrograms DES or higher resulted in absence of corpora lutea. In ovaries lacking corpora lutea, the interstitial tissue dominated and the cells in this compartment were large with a clear cytoplasm. The steroids synthesized in ovarian homogenates were separated with thin-layer chromatography. The homogeneity of the steroids was checked in recrystallization experiments. Daily doses of 5-10(-4) micrograms DES in the neonatal period resulted in pronounced deviations in the pattern of ovarian steroids synthesized as compared with control ovaries. In DES-exposed ovaries, the synthesis of androstenedione and, above all, progesterone was high while the synthesis of 17 alpha-hydroxyprogesterone and testosterone was reduced compared with controls. These results could argue for a difference in activities of 17 alpha-hydroxylase and 17 beta-ol-dehydrogenase in ovaries from DES-treated females compared with controls. After transplantation of DES-exposed ovaries to ovariectomized control females, the steroid pattern changed to that typical for control ovaries. Control ovaries transplanted to DES-treated females had a steroid pattern similar to that of DES-exposed ovaries.

17-alpha-Hydroxyprogesterone↗
PubMed1985

Ovarian progesterone synthesis and content and plasma progesterone levels in adult mice treated with diethylstilbestrol neonatally.

Ovaries from 8-week-old female NMRI mice, treated with 5 micrograms diethylstilbestrol (DES) daily for the first 5 days after birth were studied for progesterone synthesis in vitro, using 3H-pregnenolone as precursor, and assayed for progesterone content using radioimmunoassay (RIA) technique. The plasma levels of progesterone were measured with RIA. These results were compared with those from control ovaries from females in different phases of the estrous cycle. Values for radioactivity representing 3H-progesterone were significantly higher after 1-hour incubation of ovarian homogenate from DES treated females than in homogenates of ovaries from any phase of the normal estrous cycle. The ovarian content of progesterone was similar in DES exposed ovaries and ovaries from females in proestrous or estrous but lower in DES ovaries than in diestrous ovaries. The plasma levels of progesterone were in the same range in DES treated females and diestrous females but higher in DES females than in estrous or proestrous females.

Animals↗