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Biomedical subjects

S Goldstein

Publications and source records attributed to S Goldstein.

At least 577 records · Page 32Linked to original sources
PubMed1979

Diagnostic value of visualization of the right ventricle using thallium-201 myocardial imaging.

The diagnostic significance of visualizing the right ventricle on thallium-201 myocardial perfusion scans (T-scan) at rest was studied in 53 patients. In 33 patients the right ventricle was visualized clearly on the T-scan (group A). Hemodynamic evidence of right ventricular hypertension with systolic pressure greater than or equal to 30 mmHg was present in 28 of 33 (85%) of these patients. Right ventricular volume overload with left-to-right shunt greater than 2:1 was present in three patients. Other tests were diagnostic for right ventricular enlargement and or pulmonary hypertension as follows: chest x-ray (58%), echocardiogram (36%) and electrocardiogram (15%). In an unselected group of 20 patients (group B) where resting T-scan did not show visualization of the right ventricle, the right ventricular systolic pressure was less than 30 mm Hg in all. The other noninvasive tests did not reveal presence of right ventricular hypertrophy or enlargement. T-scan appears to be a useful and sensitive test in detecting right ventricular pressure or volume overload compared with other noninvasive tests. This may be useful in detection of patients with right ventricular hypertrophy or enlargement secondary to pulmonary hypertension or other causes.

Adult↗
PubMed1979

Modulating effect of regional myocardial performance on local myocardial perfusion in the dog.

We studied the effect of regional contractile performance on regional coronary blood flow and flow distribution in 10 dogs. The left anterior descending (LAD) coronary artery was cannulated and perfused. Maximal vasodilation was obtained with adenosine. Consequently, variations of LAD flow reflected changes of extravascular resistance. Lidocaine injected in the LAD caused a localized reduction of contractile performance as shown by the absence of systolic wall thickening. Global left ventricular performance and pressure were unchanged. Coronary extravascular resistance diminished and LAD flow increased from 4.8 +/- 0.5 to 6.2 +/- 0.6 ml/min per g (P less than 0.02). The endocardial: epicardial ratio increased from 1.02 +/- 0.07 to 1.28 +/- 0.07 (P less than 0.001). Isoproterenol in the LAD augmented systolic wall thickening. Regional coronary flow diminished from 5.1 +/- 0.5 to 3.3 +/- 0.4 ml/min per g (P less than 0.001), and the endocardial:epicardial ratio diminished from 1.08 +/- 0.07 to 0.75 +/- 0.07 (P less than 0.01). These data indicate that myocardial contractility is a major component of extravascular coronary resistance and is a mechanical determinant of coronary blood flow and its transmural distribution.

Animals↗
PubMed1979

Diabetes mellitus and genetic prediabetes. Decreased replicative capacity of cultured skin fibroblasts.

The idea that the gene(s) that cause diabetes mellitus can be expressed in extrapancreatic cells has been examined by tissue culture techniques. Skin biopsies were obtained from 25 normal subjects (N), 26 overt diabetics (D), 16 of juvenile onset (JOD) and 9 of maturity onset (MOD), and 21 subjects genetically predisposed to diabetes (P) on the basis of maturity-onset diabetes in both parents. Each biopsy was subdivided, multiple skin fragments were explanted in vitro, and several parameters of cellular outgrowth were monitored in primary and secondary cultures until cell division ceased because of senescence. In general, the rank order of growth vigor was N greater than P greater than D although differences were often marginal and statistically significant between N and JOD and(or) MOD. Outgrowth of epithelial cells was more vigorous in N explants in early stages, but later, JOD and MOD cells grew better than those of N. Outgrowth of fibroblast cells from N explants was more vigorous both at early and later stages and required less time to achieve maximum percent outgrowth. In secondary cultures, N cells grew faster than the other three groups so that fewer days elapsed between subcultures but significant differences were only seen between N and one or two of the other groups over some of the first seven subcultures. The onset of cellular senescence occurred earlier in P and JOD cultures both in mean population doublings and calendar time. N cultures had a higher percent surviving clones after picking than MOD, and a shorter recloning time than clones of JOD. The replicative life-spans of cultures (mean population doublings +/- SE) were N = 52.54 +/- 2.24, P = 47.84 +/- 2.43, JOD = 47.12 +/- 2.99, and MOD = 46.40 +/- 4.04, but differences did not reach significance for N vs the other three groups. The data demonstrate that cellular growth is impaired in both JOD and MOD types of cultures and to a generally lesser extent in P cultures. This is consistent with intrinsic genetic defects but the possibility that persistent deleterious effects of in vivo pathophysiology contribute alone or in combination cannot be ruled out. Therefore, the diabetic defect(s) can be expressed in extrapancreatic cells of mesenchymal origin. This system should prove useful in exploring the interplay between genetic and environmental factors in diabetes, the mechanisms(s) of hyperglycemia and other metabolic derangements, and the propensity that affected individuals have to develop degenerative diseases.

Adolescent↗
PubMed1979

Echocardiographic features of mitral obstruction due to bacterial endocarditis.

We describe a patient with mitral valvular obstruction due to vegetative endocarditis. The diagnosis was made before surgery by M-mode and two-dimensional echo-cardiograms, which revealed a mass of echoes obstructing the mitral orifice. This was confirmed subsequently at surgery. Both modes of echocardiography are of value in the noninvasive diagnosis of mitral valvular obstruction due to vegetative endocarditis, a condition which may be amenable to surgery for valvular replacement.

Aged↗
PubMed1979

The psychiatric clinical specialist in the general hospital.

The author describes her experience as a psychiatric clinical nurse specialist functioning independently in a general hospital in a variety of roles. Seven areas of involvement illustrate the wide range of patient, staff, and other needs which this nurse specialist can meet. The author wishes to thank Joanne Damon, R.N., Sandra Zion, R.N., Dorothy Markay, R.N., and Rachel Rotkovitch, R.N., for their advice, encouragement, and support, and Florence Williams, R.N., who provided clinical supervision.

Aftercare↗
PubMed1979

In vitro studies of age-associated diseases.

We have carried out studies on cultured human fibroblasts in an attempt to trace the origins of age-dependent disorders to the cellular and molecular levels. Three interrelated areas are discussed. First, skin donors with diabetes mellitus (a disease complex that features inappropriate hyperglycemia) produce cultured fibroblasts with a moderate reduction in growth capacity, while two inherited disorders of inappropriate hyperglycemia and premature aging, progeria and Werner syndrome, yield fibroblast cultures with more severely impaired growth capacity. Second, there is a decreased response of progeria level and donor age; evidence is presented that this defective hormone responsiveness in aging cells may reside at the hormone receptor on the surface membrane, the cyclic AMP system, the intracellular enzymatic machinery, or all of these sites. Third, tissue factor, a procoagulant that activates the extrinsic clotting mechanism, is more abundant in cells from the premature aging syndromes of progeria and Werner syndrome. Fibroblast aging in vitro may help to explain various concomitants of normal aging and diabetes mellitus including cell dropout, impairment of hormone responsiveness, and increased atherothrombosis.

Aging↗
PubMed1978

Limited tryptic digestion of human serum low-density lipoprotein: isolation and characterisation of the protein-deficient particle and of its apoprotein.

Limited tryptic digestion of human serum low-density (LD) lipoprotein (rho 1.024-1.045 g/ml) under defined conditions permitted isolation by gel filtration chromatography of a stable, protein-deficient lipoprotein; the liberated protein was separated as a mixture of peptides of low molecular weight (less than 5000). Comparison of the chemical, physical and immunological characteristics of the trypsin-treated LD-lipoprotein with those of the native preparation revealed several differences, including (a) a diminished protein content (loss of some 20-25% of the total protein of LD-lipoprotein) and increased proportions of the various lipid components, except for triglyceride (probably resulting from a loss of bound free fatty acids with the liberated peptides); (b) a greater heterogeneity in particle size and slightly larger mean diameter; (c) a lower hydrated density and greater peak sf rate than the native LD-lipoprotein (d) an increased net negative charge; and (e) a partial immunological identity between LD-lipoprotein and the corresponding trypsin-treated fraction. While the amino acid compositions of the protein moieties of LD-lipoprotein and of trypsin-treated LD-lipoprotein were essentially identical, trypsin-treated apo-LD-lipoprotein was distinct in its complete solubility in urea-containing buffers at high concentrations, and also in its partial solubility in buffers lacking denaturing agents. Comparison of the apoproteins of the native and trypsin-treated LD-lipoproteins by electrophoretic techniques based on molecular weight revealed a transformation of the high-molecular weight material (greater than 250 000) characteristic of apo-LD lipoprotein into several polypeptide species (10 major forms) ranging in size from 161 500 to about 10 000. The largest of these (band b1: 161 500) could be completely dissociated into smaller components (b2: 93 500 and b3: 77 000) upon extensive heat treatment at 90 degrees C. Electrophoresis of the soluble fraction of apo-LD-lipoprotein and of that from its trypsin-treated counterpart in polyacrylamide gels containing urea at basic pH showed the disappearance of the small amounts (less than 5%) of C apoproteins of apo-LD-lipoprotein upon tryptic treatment. These results, which were highly reproducible in LD-lipoprotein preparations from different individuals, suggest that trypsin-treated LD-lipoprotein may provide a model for investigation of the organisation and structural role of the prinicipal apoprotein (apolipoprotein-B) in the LD-lipoprotein molecule.

Amino Acids↗
PubMed1978

Enhanced degradation of trypsin-treated low density lipoprotein by fibroblasts from a patient with homozygous familial hypercholesterolemia.

When 125I-labeled native low density lipoprotein was incubated with skin fibroblasts from a patient with homozygous familial hypercholesterolemia, the observed rate of degradation of the protein moiety was less than 5% the rate observed with normal fibroblasts, in agreement with previous studies. When the low density lipoprotein had been first treated with trypsin, with release of about 20% of the protein, its degradation by the patient's fibroblasts was markedly increased 8-20-fold. In contrast, the rate of degradation of the trypsin-treated lipoprotein by normal fibroblasts was, if anything, slightly reduced. In neither the normal cells nor the patient's cells was binding to the cell surface appreciably altered by trypsin treatment of the lipoprotein. Prior incubation with cholesterol and 7-ketocholesterol reduced binding of trypsin-treated low density lipoprotein to normal cells by 67% but did not affect its binding to the patient's cells. The results show that the structural modifications induced by trypsin do not interfere with binding of low density lipoprotein to its normal high affinity receptor nor its degradation by normal cells. However, the modified lipoprotein is much more readily internalized and degraded by cells from the patient with homozygous familial hypercholesterolemia.

Apolipoproteins↗
PubMed1978

Chronologic and physiologic age affect replicative life-span of fibroblasts from diabetic, prediabetic, and normal donors.

Cultured skin fibroblasts from subjects with clinically apparent diabetes mellitus and from subjects genetically predisposed to diabetes have a replicative lifespan that is inversely related to donor age. Fibroblasts from carefully defined normal subjects not predisposed to diabetes fail to show this correlation. The data support the idea that physiologic status of the tissue donor is a more precise determinant of fibroblast replicative lifespan than chronologic age.

Adolescent↗
PubMed1978

An analysis of cercopithecoid odontometrics. I. The scaling of the maxillary dentition.

The relations between two tooth indices, post-canine area and incisor width in the upper jaw, and three variables, diet, body weight and body weight dimorphism, were examined separately for the males and females of 29 cercopithecoid species. Each species was assigned to one of three diet classes (folivore, frugivore, omnivore). Data on the other variable consisted of species means (log-transformed) obtained from published sources. The analytic techniques used were bivariate and multiple regression, the tooth indices being the dependent variables. All tooth indices scaled isometrically within diet classes, and all except female incisor width scaled with positive allometry across diet classes. In both sexes, the body weight adjusted mean incisor width of folivores was significantly smaller than that of either frugivores or omnivores. In the females, the body weight adjusted mean post-canine areas did not differ significantly across diet classes, while in the males the omnivores had a larger body weight adjusted mean post-canine area than either the folivores or frugivores. Female post-canine area was the only tooth index for which body weight dimorphism was a significant predictor. Extrapolations of these findings to other extant and to fossil primate species are discussed.

Animals↗
PubMed1978

An analysis of cercopithecoid odontometrics. II. Relations between dental dimorphism, body size dimorphism and diet.

Odontometric, dietary, and body weight data were collected for a sample of 29 cercopithecoid species. Each species was assigned to one of three diet classes (frugivore, folivore, and omnivore) , and indices were constructed to estimate the extent of sexual dimorphism in body weight, postcanine area and incisor width in each of the species. Analysis proceeded by means of the analysis of covariance with the dental dimorphism indices as the dependent variables. Body weight dimorphism was not significantly related to either measure of dental dimorphism across the sample, and an analysis by diet alone revealed that omnivores show significantly higher dental dimorphism than do either of the other two diet classes. The relationship between this result and theories of sexual subniche differentiation is discussed.

Animals↗