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Biomedical subjects

J Wiener

Publications and source records attributed to J Wiener.

At least 55 records · Page 3Linked to original sources
PubMed1989

Relationship between social perception and peer status in children with learning disabilities.

This study was undertaken to examine the social perceptual skill deficit theory in explaining the low peer acceptance of children with learning disabilities. The quality of tests measuring social perception was also examined. Thirty 9- to 12-year-old children with learning disabilities and a matched control group were given two measures of social perception: a laboratory task and a behavior rating scale. The behavior rating scale was completed by the children's teachers. In addition, the Peer Acceptance Scale (Bruininks, Rynders, & Gross, 1974) was administered to assess peer status. Results showed that the children with learning disabilities differed significantly from their nondisabled peers on each of the three measures-the children with learning disabilities obtained lower social perception and peer acceptance scores. However, the relationships between sociometric status and social perception varied as a function of task. A small but significant correlation wa found between the behavior rating scale and peer status. The laboratory task was not correlated with either the behavior rating scale or peer status. Results are discussed in terms of the psychometric properties of laboratory versus naturalistic measures of social perception and the importance of establishing the external validity of social skill measures by correlating them with outcome measures such as peer status.

Child↗
PubMed1989

Angiogenesis in rat aorta ring explant cultures.

This report describes the utilization of rat aorta "rings" as explants to study angiogenesis. Under short-term culture conditions, ring explants transferred at 3- to 4-day intervals showed growth (differential migration) of endothelial and/or smooth muscle cell populations. On the other hand, explants maintained for long-term (up to 3 weeks) without transfer, developed extensive out-growths of new vascular channels radiating on and through the established cell sheet. Examination of adventitia stripped ring segments, before culture revealed the presence of areas containing small vessel remnants embedded in the outer aorta wall. In addition, cultures of adventitial tissue alone yielded a variety of cell types including the occasional presence of vascular cells with developing channel formation. Immunofluorescent and ultrastructural examination of long-term aorta explant cultures revealed that these channels consisted of endothelial cells that exhibited positive reactivity for factor VIII antibody. In order to determine the influence of aorta-derived cells on vascular channel development, various vessel treatments and manipulations were performed before explant culture, to eliminate the influence of either the endothelium and/or adventitia-associated microvasculature remnants. Thus results clearly showed that the presence of both constituents is required to initiate the angiogenic response in this in vitro culture model. In addition, short-term aortic ring explant culture is an efficient and reliable technique for the isolation and culture of endothelium and smooth muscle cells from large vessels of the rat. More importantly, long-term maintenance of aorta explant cultures provides a novel self-contained system to study new vessel growth and development, and represents an attractive alternative model for defining the cellular processes regulating angiogenesis.

Animals↗
PubMed1988

Structural analysis of the calcium channel by photoaffinity labelling and limited proteolysis.

The L-type calcium channel of rabbit skeletal muscle triads, purified from digitonin extracts, was photolabelled with the dihydropyridine (+)[3H]PN 200-110. This photolabelled form was then subjected to limited proteolysis with papain and staphylococcus V-8 protease and analyzed by polyacrylamide gel electrophoresis. In the absence of proteolysis, the photolabelled channel was represented by a single protein with an apparent molecular weight of 160 kDa in the presence or absence of reducing agents. Following proteolysis, numerous photoadducts were observed with smaller molecular weights. The V-8 protease digestion pattern indicated that photoinsertion occurred in at least two distinct domains of 33 and 28 kDa. Papain digests were more extensive, generating smaller fragments of 28 and ca. 10 kDa. The results suggest that at least two distinct regions of the calcium channel interface at or near the dihydropyridine binding site, and that the binding site for these calcium antagonists resides within the channel proper, thereby modulating calcium influx.

Affinity Labels↗
PubMed1988

Rat heart-derived endothelial and smooth muscle cell cultures: isolation, cloning and characterization.

This report describes the initiation, cloning and establishment of long-term serial cultures of rat heart-derived vascular endothelial (EC) and smooth muscle cells (SMC). Populations of these cells derived from both the macro-and microcirculation were obtained utilizing isolated heart perfusion technique. Elimination of potential mesothelial cell contamination was achieved by ethanol fixation of the pericardial surface prior to perfusion. Initial outgrowths from perfusate yielded both endothelial (rapid adhering) and smooth muscle (slow adhering) appearing cell populations. Subsequent pooling of individual EC colonies resulted in maintaining, with gradual subcultivation, a stable homogeneous population which was designated RHE-parent. Upon continual subculture late passage (greater than P10) RHE-parent cell cultures expressed a marked heterogeneity in endothelial phenotypes. Cloning experiments resulted in establishing two distinct EC populations designated RHE-clone 1A and RHE-clone 2A. All RHE cell cultures exhibited the typical cobblestone growth pattern and positive immunofluorescent staining for factor VIII related antigen. In contrast, rat heart-derived smooth muscle cell (RH-SMC) cultures displayed the typical multilayered 'hill and valley' pattern and positive fluorescence for SMC-specific actin and myosin antibodies. Additional EC preparations, obtained without prior fixation of the pericardial surface, revealed cell clusters which stained positive for cytokeratin. On the other hand, RHE parent and cloned populations stained exclusively for vimentin, further confirming the absence of mesothelial cell contamination in these cultures. Cell growth studies on early (less than P10) and late (greater than P10) passage RHE-parent population revealed markedly different cell growth responses and cell morphology. Both EC cloned populations and more notably RHE-parent (less than P10) cultures were capable of significant growth when maintained in limiting serum concentration. Growth studies using serum-free RHE-parent conditioned medium demonstrated mitogenic activity when tested on RHE-parent cultures indicating the presence of an endothelial cell-derived growth factor. These studies indicate that long-term RHE and RH-SMC derived cell cultures can serve as a useful model to study the biology of vascular cells derived from different sites. In addition the demonstration of mitogenic activity in these cultures will enable us to explore further the nature of this response and compare this phenomenon with growth factors identified in large vessel cell systems.

Animals↗
PubMed1988

Autonomic receptor characterization in cultured adult rat cardiac myocytes: morphologic-functional correlation.

Adult calcium tolerant rat ventricular myocytes were maintained under serum-free culture conditions for five days. beta-adrenergic and muscarinic cholinergic receptor expression was assessed by radioligand binding determinations using 125I-iodocyanopindolol (ICYP) and [3H]-quinuclidinyl benzilate (QNB), respectively. The binding data were correlated with myocyte structural integrity and contractile responsiveness to norepinephrine (NE). During the 5 days in primary culture, beta-adrenergic and muscarinic cholinergic receptor binding capacity diminished Bmax = 17.1 to 9.2 fmol/mg protein and Bmax = 169.0 to 26.6 fmol/mg protein, respectively. The affinity of both autonomic receptors was unaltered during the period of observation. The majority of isolated myocytes were viable (65 to 85%) and remained rod-shaped for 5 days as assessed by phase contrast microscopy. Up to 2 days in vitro the rod-shaped myocytes appeared ultrastructurally similar to their in vivo counterparts and displayed intact nuclei and the usual complement of cellular organelles. From day 3, phase contrast as well as transmission electron microscopy revealed a progressive increase in autophagic vacuoles consisting primarily of disrupted mitochondria. The number of myocytes that contracted in response to norepinephrine (NE) decreased from 57.2 to 2.3% by day 5. These data indicate that adult rat cardiac myocytes maintained in serum free culture for 5 days, express beta-adrenergic and muscarinic cholinergic receptors. There is a rapid decline (50%) in muscarinic cholinergic receptor number and contractile response to NE by day 2. However, the decrease in beta-receptor Bmax by day two is insufficient to explain the severe loss of cell responsiveness to NE. This functional loss may be related, at least in part, to the ultrastructural abnormalities that are first evident at day 2 in culture. Thus, short-term myocyte cultures that retain phenotypic and physiologic characteristics of in vivo cardiac myocytes could provide a useful in vitro system for exploring pharmacologic-functional interactions in the myocardium.

Animals↗
PubMed1988

Altered calcium regulation in the cardiac plasma membrane in experimental renal hypertension.

The factors regulating calcium homeostasis in the cardiac plasma membrane of renal hypertension in the rat (two kidney-one clip, Goldblatt model) have been studied. Comparison of the cardiac sarcolemma from control (C) and hypertensive (H) rats indicates similar protein yield and purity. Study of longer term hypertension (4 to 12 weeks) shows a decrease in the number of calcium channel receptor binding sites (Bmax C: 549 +/- 122 fmol/mg; H: 334 +/- 74 fmol/mg) as well as a depressed calcium pumping ATPase activity (C: 7.6 +/- 2.5 nmol/mg/min; H: 3.8 +/- 1.5 nmol/mg/min). Furthermore, there is a decreased rate of Na+-Ca2+ exchange (C: 5.4 +/- 1.9 nmol/mg/5 s; H: 2.3 +/- 0.9 nmol/mg/5 s). Study of short-term hypertension (1 to 4 weeks) indicates that the earliest change occurs at 1 week with decreased calcium pumping ATPase due to a change of the Vmax of Ca2+ transport (C: 9.7 +/- 1.6 nmol/mg/min; H: 5.4 +/- 1.4 nmol/mg/min). This is then followed by the decreased calcium channel receptor binding. However, the rate and the extent of depression in Ca2+-ATPase activity are much greater than that of Ca2+ channel receptor binding. Since alteration of Ca2+-ATPase is accompanied by an increase in intracellular Ca2+ concentration and there is a temporal association with the onset of myocardial lesions in the hypertensive rats, it is suggested that elevated intracellular calcium concentration as a result of altered Ca2+-ATPase activity may play a significant role in the development of hypertensive cardiomyopathy.

Animals↗
PubMed1987

Photoaffinity labeling of the calcium channel antagonist receptor in the heart of the cardiomyopathic hamster.

The high affinity 1,4-dihydropyridine receptors of the cardiac membrane calcium channel from Syrian Cardiomyopathic hamsters were studied using [3H] PN200-110 and [3H]azidopine as ligands. [3H]Azidopine was photoincorporated covalently into bands of 180, 100, 79, 45 and 31 kDa, as determined by SDS/polyacrylamide gel electrophoresis. Photolabeling of the 180 kDa band is protected by 2 microM [1H]PN200-110 whereas the lower Mr bands are not. Thus, only the 180 kDa band is the calcium channel linked 1,4 dihydropyridine receptor. The photoincorporation into this 180 kDa band is doubled with samples of myopathic hamsters vs. control hamsters. It is suggested that the increase in calcium channel receptors may be involved in the pathogenesis of this cardiomyopathy.

Affinity Labels↗
PubMed1987

Defective Ca2+-pumping ATPase of heart sarcolemma from cardiomyopathic hamster.

The Syrian cardiomyopathic hamster has a hereditary disease characterized by a progressive myocyte necrosis and intracellular calcium overload. Several systems in the heart sarcolemma that regulate the rate of Ca2+ entry or efflux were examined. There is a selective decrease of Ca2+-pumping ATPase activity in the heart sarcolemma of 40-day-old myopathic hamsters, while the Na+-Ca2+ exchange system and the ouabain-sensitive (Na+ + K+)-ATPase activity remain intact. This age-dependent decrease in Ca2+-ATPase activity closely parallels the time course of lesion development. Both the affinity for Ca2+ (Km) and the maximal velocity (Vmax) of the Ca2+-dependent ATP hydrolysis are altered. In addition, there is also an increased number of calcium channel receptor binding sites. Thus the data suggest that the imbalance in Ca2+ fluxes across the cardiac plasma membrane may be involved in the pathogenesis of this cardiomyopathy.

Adenosine Triphosphate↗
PubMed1987

Calcium-activated protease in hamster cardiomyopathy.

A high calcium-requiring protease was purified from the hearts of myopathic hamsters. The biochemical properties of the enzyme were studied with [3H]acetylcasein as substrate. Comparison of the enzyme from hamster and rat hearts indicated no species specificity. Increased levels of the enzyme were associated with the development of cardiac lesions in myopathic hamsters.

Animals↗
PubMed1986

Mitochondrial protein phosphorylation and cardiomyopathy in genetically diabetic mice: the effect of estrone treatment.

The alpha-subunit of pyruvate dehydrogenase and succinyl-CoA synthetase are phosphorylated after incubation of cardiac mitochondria from genetically diabetic mice with [gamma-32P]ATP. There is significantly increased incorporation of 32P into pyruvate dehydrogenase from diabetic mice when compared to controls. The enhanced rate of pyruvate dehydrogenase phosphorylation correlates well with the previously reported defective oxidative metabolism and decreased activity of this enzyme from diabetic mice. The relationship between abnormal mitochondrial function and development of cardiomyopathy in the diabetic mice has been studied further by in vivo estrone treatment. The results indicate that ultrastructural alterations of myocardium are closely associated with the defective pyruvate oxidation (via phosphorylation of pyruvate dehydrogenase) and both processes can be prevented by 7-12 weeks estrone treatment.

Animals↗
PubMed1986

Rat cerebral microvascular smooth muscle cells in culture.

This report describes the development and establishment of long-term serial cultures of adult rat vascular smooth muscle cells (SMC) derived from cerebrocortical resistance vessels (small arteries and arterioles). Electron microscopic examination of microvessels isolated off a 150 microns nylon mesh sieve clearly demonstrated the predominance of these vessel types. Initial outgrowth from collagenase-elastase-treated microvessel fragments yielded both endothelium and smooth muscle cells. However, at confluency (2-3 weeks) these cultures consisted of a homogeneous population of broad, polygonal cells that grew in a multilayered "hill and valley" pattern typical of SMC in vitro. For comparative morphological and functional studies, SMC cultures were also initiated from rat thoracic aortas utilizing ring segments as explants. The smooth muscle origin of cultures derived from both resistance vessel (RV) and aorta (RA) was further demonstrated by positive immunofluorescent staining by the specific smooth muscle alpha-actin and myosin antibodies. Ultrastructural examination of these SMC cultures revealed similar morphologic features consisting of typical cytoplasmic myofilament bundles with associated dense bodies and numerous pinocytotic vesicles. Cell growth studies on early (less than P 15)- and late (greater than P 15)-passage RV- and RA-SMC populations revealed markedly different cell growth responses. Representative growth curves of early- and late-passage RA-SMC showed a significantly higher growth rate (two- to fourfold) than RV-SMC cultures. Both cultures, however, exhibited a marked increase in growth potential at higher passage levels. Heparin, at a concentration of 100 micrograms/ml inhibited the growth of RV-SMC during the first 3 days after addition in both exponential and growth-arrested culture states, whereas RA-SMC cultures showed no inhibitory response. These studies indicate that long-term RV-SMC cultures can serve as a useful model system to study functional and metabolic properties of this cell type and provide the means to explore further the heterogeneity of SMC derived from different vasculatures in normal as well as various disease states.

Animals↗
PubMed1986

Case-mix differences between hospital-based and freestanding skilled nursing facilities. A review of the evidence.

Many health care services are available in both hospital and freestanding settings. Hospital-based providers are usually much more expensive than freestanding providers. According to Medicare data, costs in hospital-based skilled nursing facilities (SNFs) are twice those of freestanding facilities. While critics charge that this is the result of inefficiency, hospitals counter that higher costs are caused by treatment of sicker patients and provision of higher-quality care. This paper analyzes the research on the case-mix differences between hospital-based and freestanding SNFs. On the basis of this analysis, it appears that hospital-based facilities tend to serve more severely ill patients (i.e., have a more difficult case mix) than do freestanding facilities. Case-mix differences, however, appear to explain less than half of the cost differential between the two types of facilities.

Costs and Cost Analysis↗
PubMed1986

Prospective payment for Medicare skilled nursing facilities: background and issues.

Strong interest by Congress in a Medicare prospective payment system for skilled nursing facilities (SNF's) resulted in a major study by the Health Care Financing Administration on the Medicare SNF benefit. This article highlights findings from that study, which addressed the following: the Medicare SNF benefit, utilization and expenditures, the Medicare SNF industry, problems with the current Medicare SNF reimbursement system, efforts to develop a Medicare SNF case-mix measure, and case-mix differences between hospital-based and freestanding SNF's. In addition, we discuss the implications of the study findings for the design of a Medicare SNF prospective payment system (PPS).

Costs and Cost Analysis↗
PubMed1986

The feasibility of using case mix and prospective payment for Medicare skilled nursing facilities.

Congress, at the time it asked for a feasibility study of the use of prospective payment for hospital care delivered to Medicare patients, also asked for a study of the Medicare skilled nursing facility (SNF) benefit. The information and commentary in this paper are based on the history and findings of the recent Health Care Financing Administration study of the SNF benefit. We discuss the technical, administrative, and policy issues that need to be addressed to implement a patient-level case-mix adjustment for reimbursing SNFs under Medicare. We conclude that conditions are currently not ideal for implementing a patient-level case-mix adjustment for Medicare SNFs. Future research may be able to remedy some of the impediments to adapting case-mix adjustments for SNFs.

Activities of Daily Living↗
PubMed1985

Purification and characterization of two distinct Ca2+-activated proteinases from hearts of hypertensive rats.

Two distinct Ca2+-activated proteinases were purified and characterized from hearts of hypertensive rats. Ca2+-activated proteinases I and II, having low and high Ca2+ requirements, respectively, were first separated by DEAE-cellulose chromatography. The enzymes were then purified individually by different column procedures: chromatography on phenyl-Sepharose, then Sephadex G-200 for proteinase I and reactive-red agarose for proteinase II. The apparent molecular weight of purified proteinase I was 125 000 and that for purified proteinase II was 110 000. Both enzymes are heterodimers made up of a larger catalytic subunit and a smaller subunit devoid of proteinase activity. Ca2+ concentrations for half-maximal activation were 5 microM for proteinase I and 200 microM for proteinase II. Both enzymes were inhibited by sulfhydryl-modifying agents, but exhibited different characteristics in the auto-digestion reaction in the presence of Ca2+. Proteinases I and II were also purified from hearts of normotensive rats and shown to be identical to their respective counterparts from hearts of hypertensive rats. However, proteinase II activity in hypertensive rat hearts was significantly elevated as compared to controls.

Animals↗
PubMed1985

Oxidative metabolism of Polytron versus Nagarse mitochondria in hearts of genetically diabetic mice.

We have shown previously that heart mitochondria obtained by the Nagarse method from genetically diabetic mice (C57BL/KsJ db/db) exhibit a defect in oxidizing NAD+-linked substrates (Kuo, T.H., Moore, K.H., Giacomelli, F. and Wiener, J. (1983) Diabetes 32, 781-787). In this study, the oxidative phosphorylation characteristics of cardiac mitochondria isolated by the Polytron method were compared with that of Nagarse mitochondria. Evidence is presented here that in the diabetic heart both Nagarse and Polytron mitochondria have defective pyruvate oxidation, whereas only the former exhibit impaired fatty acid oxidation. Assay of two rate-limiting beta-oxidation enzymes, namely beta-hydroxyacyl-CoA dehydrogenase and beta-ketothiolase, indicates no alteration in specific activities from diabetic mice vs. controls. The data suggest that two populations of mitochondria are present in myocardium and that the defective oxidative metabolism in the cardiac mitochondria of db/db mice may be linked to deficiencies in total NAD + NADH content.

3-Hydroxyacyl CoA Dehydrogenases↗
PubMed1985

Morphometry of superficial glomeruli in acute hypertension in the rat.

Pressor doses of angiotensin II (AII) were infused intravenously in Munich-Wistar rats to study the effects of acute hypertension on the structural components of the superficial renal corpuscles and urinary protein excretion. All administration raises arterial blood pressure by 38% and increases 13-fold the normal rate of urinary excretion of proteins that contain albumin and IgG. Morphometric analysis of the quantitative characteristics of the glomerular capillaries reveals a 24% increase in the mean cross-sectional area of the capillary profiles and a 33% expansion of the capillary luminal volume. The amount of extracellular material present in the mesangium is also increased by 76%. The surface area of basement membrane available for ultrafiltration remains constant. However, the length density and the total length of the filtration slit diaphragms are reduced by 35 and 24%, respectively. Thus, the major findings of this investigation are as follows: The presence of IgG in the urine suggests a size defect in the glomerular filter with AII-induced hypertension; the dilatation of capillary loops may result in mechanical stretching of the basement membrane, altering the size-selective properties of the glomerular filter in acute hypertension; and the reduced pore area of the filtration slit diaphragms implies a lower hydraulic conductivity of the glomerular filter that may be responsible for the decreased glomerular capillary ultrafiltration coefficient present in this model of hypertension.

Acute Disease↗