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Biomedical subjects

S Goldstein

Publications and source records attributed to S Goldstein.

At least 487 records · Page 27Linked to original sources
PubMed1984

Sex differences in biological factors putatively related to depression.

Gender differences in the prevalence of affective disorders were suggested by several authorities in the field. Such differences may be attributed to sex-related differences in levels or activity of monoamine transmitters, especially since some of these variables have been shown to be altered by gonadal hormones. The reported association of perimenstrual and postpartum dysphoria, with affective disorders may contribute to further elucidation of pathophysiology of depression in women--in light of the hormonal-behavioral dynamics of these periods. Several factors associated with monoamines biosynthesis, availability, uptake and metabolism were found to be more abnormal in normal and depressed women compared to men. Age-sex differences in some biological markers for depression are reported as well. Their relevance to the underlying pathophysiology of depression is unclear but they may provide clues for further research.

Acetylcholine↗
PubMed1984

Low-density lipoprotein binding sites in the microvillous membranes of human placenta at different stages of gestation.

Microvillous membranes isolated from early gestation placentas (8-12 weeks of amenorrhoea) and from mid-term placentas (20-22 weeks of amenorrhoea) were used to study the specific binding of low-density lipoprotein (LDL) to the trophoblast. The purity of the microvillous preparations has been assessed by electron microscopy and by their enrichment in two membrane markers, 5'-nucleotidase and alkaline phosphatase. Evidence was presented demonstrating the existence of saturable binding sites for [125I]LDL in placental microvilli as early as 6 weeks of pregnancy. The apparent KD values for these binding sites have been determined by Scatchard analyses to be 6.98 +/- 0.83 and 6.57 +/- 0.81 micrograms protein LDL/ml, for early gestation and mid-term preparations, respectively. This apparent KD value was unaffected by a pretreatment of the membranes by heparin, as indicated by the mean values of 7.13 +/- 0.89 and 6.97 +/- 0.75 micrograms protein LDL/ml obtained for immature microvilli preincubated with or without heparin, respectively. Large variations of binding capacity were observed in each gestational age group and no significant difference was found between them. These results indicate that the LDL binding sites of the human placenta, located on the microvillous membranes, (i) are present as early as the 6th week of pregnancy, and (ii) display the same high affinity and specificity for LDL as those of the term trophoblast.

5'-Nucleotidase↗
PubMed1984

Timing, mechanism and clinical setting of witnessed deaths in postmyocardial infarction patients.

The temporal distribution and mechanism of death were studied in a large multicenter secondary prevention trial (Aspirin Myocardial Infarction Study) in which acute witnessed death represented 72% (270 of 376) of the deaths due to arteriosclerotic heart disease. Instantaneous deaths represented 28.9% (78 of 270) of the acute witnessed deaths; 45.2% (122 of 270) occurred in the first hour after the onset of symptoms and were defined as sudden deaths. In the subsequent 23 hours, an additional 113 deaths (41.8%) occurred and were defined as intermediate deaths; 29 late deaths (10.7%) occurred after 24 hours. Cardiac arrhythmia was the mechanism of death in 83% (194 of 235) of deaths within 24 hours. Univariate analysis of baseline clinical and electrocardiographic characteristics indicates that a history of congestive heart failure, cardiomegaly, angina pectoris, multiple myocardial infarctions and therapy with digitalis and nitroglycerin were more common in those who died than in survivors, regardless of the timing of death.

Arrhythmias, Cardiac↗
PubMed1984

Interaction of N4-hydroxy-2'-deoxycytidylic acid with thymidylate synthetase.

The interaction of dTMP synthetase with N4-hydroxy-2'-deoxycytidylate (N4-HOdCMP) has been investigated. With use of standard assay conditions, N4-HOd-CMP is a competitive inhibitor with an apparent Ki of 8.0 microM. Incubation of N4-HOdCMP with dTMP synthetase in the presence of 5,10-methylenetetrahydrofolate (CH2-H4folate) resulted in a rapid time-dependent inactivation of the enzyme which was not first order and the formation of complexes which could be isolated on nitrocellulose filter membranes. With use of radioactive ligands, the isolable native complex was shown to possess 2 mol of N4-HOdCMP and 2 mol of CH2-H4folate/mol of dimeric enzyme; the apparent dissociation constant of N4-HOdCMP was 1.0 microM. Ultraviolet difference spectroscopy of the ternary complex showed a loss of the pyrimidine chromophore which did not reappear upon denaturation with NaDodSO4. The rate of dissociation of N4-HOdCMP from the ternary complex was biphasic in which one-half of the initially bound ligand dissociated with t 1/2 congruent to 2.3 min and the remainder with t 1/2 congruent to 13 min. When the N4-HOdCMP-CH2-H4folate-enzyme complex was denatured, one-half of the CH2-H4folate dissociated whereas all of the N4-HOdCMP remained bound to the enzyme. Taken together, our results indicate that N4-HOdCMP forms a covalent bond with dTMP synthetase and reveal an unusual asymmetry in the two subunits of the N4-HOdCMP-CH2-H4folate-enzyme complex. It appears that one subunit is covalently bound to N4-HOdCMP, which, in turn, is covalently linked to CH2-H4folate whereas the other subunit is covalently bound to N4-HOdCMP but CH2-H4folate is bound by noncovalent interactions.

Carbon Radioisotopes↗
PubMed1984

Implantation of brain tumors with Cf-252. Use of computed tomography and magnetic resonance imaging to guide insertion and evaluate response.

Magnetic resonance imaging (MR) was evaluated as a guide to planning and follow-up of Cf-252 neutron brachytherapy in 8 patients with malignant glioma of the cerebral hemispheres. A combination of sagittal, transverse, and coronal views allowed three-dimensional assessment of the dimensions and extent of tumor; by comparison, CT scans delineated the tumor less sharply, multiple views were not routinely obtained, and the reconstructed sagittal images were inadequate. Both techniques were complementary in enabling accurate tumor localization as well as separating enhanced zones from central avascular regions and tumor from edema. However, MR images provided more detail than serial CT scans, making MR the preferred method of follow-up.

Brachytherapy↗
PubMed1984

Plasma lipids, lipoproteins and apolipoproteins AI, AII, and B in renal transplanted children: what risk for accelerated atherosclerosis?

The aim of the study was to investigate the atherosclerosis risk factors related to hyperlipidemia in renal transplanted children. Plasma cholesterol, triglycerides, apolipoproteins (Apo) AI, AII and B, and the major lipoprotein classes separated by gradient ultracentrifugation were compared in 30 renal transplanted patients and 14 healthy children. Hyperlipidemia was present in 66% of the transplanted children. 'Positive' risk factors for atherosclerosis (high plasma cholesterol and Apo B) were present in hypercholesterolemic and combined hyperlipidemic subgroups. All transplanted children, whether normo- or hyperlipidemic, presented essentially 'negative' risk factors for atherosclerosis, i.e. significantly higher levels of Apo AI and AII in plasma and in high-density lipoprotein HDL2 and higher Apo AI/Apo B and/or Apo AII/B ratios. Repeated evaluations (over a 12-month period) in transplanted children indicated relatively frequent individual changes in the lipid pattern, but not in Apo AI and AII content. These results suggest that the risks for accelerated atherosclerosis related to hyperlipidemia may be considered as moderate in transplanted children.

Adolescent↗
PubMed1984

Subarachnoid hemorrhage in an adolescent with spontaneous occlusion of the left middle cerebral artery and reconstruction by collateral vessels (Moyamoya phenomenon).

A case of a 12-year-old girl with subarachnoid hemorrhage and a hematoma in the pineal region is reported. With cerebral angiography, an occlusion of the left middle cerebral artery and its reconstruction by numerous dilated lenticulostriate collateral vessels were demonstrated. Subarachnoid hemorrhage in children with Moyamoya phenomenon is a rare event that may result from rupture of dilated collateral vessels or associated microaneurysms.

Arterial Occlusive Diseases↗
PubMed1984

Cellular and molecular biological studies on diabetes mellitus.

Our studies indicate that physiological rather than the chronological age is the important determinant of the replicative life-span of cultured cells. It is probable that excessive cellular turn-over, which can be produced by a variety of mechanisms such as excessive nutritional or hormonal stimulation, will accelerate cellular aging, with possible biological consequences. On the other hand, the biological clock appears to be intrinsic to every cell. This was shown for fibroblasts, hepatocytes, smooth muscle cells, and epidermal keratinocytes. All these cell types have a limited division potential, which is inversely proportional to the age of the donor and to the number of previous replications. On the other hand, there is a great heterogeneity in every differentiated cell line in this respect. These results in the individual capacity of every cell to express in its own inherent pathology, at different moments during its life cycle. As far as diabetes is concerned and its micro- and macro-vascular pathology, the modification of the single cell line could lead to obstructive microvascular pathology, to atherosclerotic plaques. We demonstrated that cells obtained from insulin dependent, or insulin independent diabetics can exhibit abnormal replicative capacity in vitro. Especially in adult onset diabetes, we could show the presence of a high proportion of cells, which age more rapidly than normal.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗