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R S Weinstein

Publications and source records attributed to R S Weinstein.

At least 145 records · Page 8Linked to original sources
PubMed1986

Red cell comets: ultrastructure of axial elongation of the membrane skeleton.

In order to study intact red cell membrane skeletons, we developed two methods for the electron microscopic study of stress-ruptured and partially opened glutaraldehyde pre-fixed Triton shells of red cell ghosts. Both methods showed continuous networks of fine filaments decorated and apparently crosslinked by elongated particles. Our electron micrographs show a filamentous component that is morphologically consistent with F-actin. Quantitative considerations, including the dimensions of the elongated particles and published estimates of the number of particles in situ, suggest that compact spectrin decamers or dodecamers may exist in intact red cells. Long filaments consistent with F-actin appear to be decorated with the putative spectrin particles.

Actins↗
PubMed1986

On the thickness of the red cell membrane skeleton: quantitative electron microscopy of maximally narrowed isthmus regions of intact cells.

The thickness of the red cell membrane skeleton was deduced from measurements of the isthmus zones of intact cells that were maximally narrowed by one of two independent methods. The first method involved application of viscous drag to red cells entrapped between spider web fibers. The second method utilized cellular dehydration followed by spectrin denaturation at 49.5 degrees C. Measurements on thin sections showed that the isthmus is narrowed to approximately 120 nm by either method, suggesting that the membrane skeleton occupies a zone beneath the lipid bilayer that is up to 60 nm in thickness. The tertiary and quarternary structure of band 3, a major integral membrane protein that anchors the membrane skeleton to the lipid bilayers may be a critical determinant of the location of the membrane skeleton within the red cell.

Biomechanical Phenomena↗
PubMed1985

Expression of blood-group-related antigens in carcinoma in situ of the urinary bladder.

Expression of epithelial ABH blood group antigens and the T (Thomsen-Friedenreich)-antigen was quantitatively studied by immunoperoxidase techniques in nine cystectomy specimens containing extensive carcinoma in situ (CIS), and also histologically benign epithelium. CIS areas typically showed abnormal expression of both ABH and T-antigens and a distinctive vascular architecture, revealed by endothelial ABH staining. Histologically normal epithelium generally was antigenically normal, but occasionally showed abnormalities of either ABH or T-antigens. Antigen expression was variable in histologically atypical epithelium, with significant segments showing abnormalities of either ABH or T-antigen, and sometimes of both antigenic markers. It is postulated that histologically benign, but antigenically abnormal, epithelium may represent low-grade CIS of the urinary bladder. Assessment of blood-group-related antigen expression in flat atypical epithelium of the urinary bladder may be useful for predicting the biologic potential of these lesions.

ABO Blood-Group System↗
PubMed1985

Band 3 protein of the red cell membrane of the llama: crosslinking and cleavage of the cytoplasmic domain.

Comparative studies were done on the cytoplasmic domain of the band 3 protein in the red cell membranes of the the human and the llama. Two approaches were used: crosslinking with o-phenanthroline/CuSO4, and cleavage with 2-nitro-5-thiocyanobenzoate. o-Phenanthroline/CuSO4 crosslinks the band 3 polypeptide chains in the human; in contrast band 3 in the llama is minimally crosslinked by this agent. 2-Nitro-5-thiocyanobenzoate cleaves band 3 in the human into a 23,000-dalton fragment; a similar fragment is not generated from the llama band 3. These studies show that the cysteine residue located 23,000 daltons from the N-terminus of band 3 in the human involved in these reactions is unavailable for crosslinking and cleavage in the llama. Species differences in the cytoplasmic domain of band 3 may contribute to the unusual resistance of llama red cells to osmotic, chemical and physically-induced deformation.

Animals↗
PubMed1985

Changes of cell shape and surface charge topography in ATP-depleted human red blood cells.

ATP depletion crenates human red blood cells. With ferritin-avidin (FA) and cationized ferritin (CF) cell surface labeling, it is demonstrated that the discocyte----crenated shape transformation alters the two-dimensional topography of negative charge sites. With restoration of ATP levels, cell shape and charge topography return to normal. Concurrent changes in red cell shape and surface charge topography can be explained by associations between membrane integral proteins and the red cell cytoskeleton.

Adenosine Triphosphate↗
PubMed1985

Cell-to-cell fusion of lens fiber cells in situ: correlative light, scanning electron microscopic, and freeze-fracture studies.

We have discovered cell-to-cell fusion between fiber cells of adult frog lenses in situ. Stereo scanning electron microscopy (SEM) revealed fusion between neighboring fiber cells in radial cell columns (RCCs) and in the same growth ring, respectively. Cell-to-cell fusion of fiber cells in the lens produced fusion zones that in cross-section were larger and of different polygonal shapes than unfused fiber cells. The shape and sizes of fiber cells surrounding fusion zones and the alignment of RCCs were also altered. Serial sectioning through fusion zones confirmed that they were areas of cell-to-cell continuity established by the union of neighboring fiber cells as seen by SEM. Fusion zones represent a previously unrecognized intercellular pathway in the adult frog lens. Although numerous fusion zones were seen throughout the lens cortex and nucleus, cell-to-cell fusion was rarely observed to have occurred between elongating fiber cells. Interestingly, communicating junctions with an unusual ultrastructure that closely resembles the appearance of membranes in the process of fusion demonstrated in other systems were frequently seen in the region of the superficial cortex where fusion zones were most numerous. The fact that such unusual communicating junctions were not found in any other region of the lens leads us to speculate that structural changes in fiber cell communicating junctions may herald the formation of fusion zones and that the initial site of cell-to-cell fusion between fiber cells may be within communicating junctional plaques.

Animals↗
PubMed1985

Beta blocker overdose with propranolol and with atenolol.

During a one-month period, two cases of beta-adrenergic blocker overdose were treated by the emergency staff at our hospital. One case of propranolol intoxication demonstrated profound cardiovascular collapse and generalized tonic-clonic seizures. The condition failed to respond to high-dose intravenous pressor agents, but did improve significantly with IV glucagon infusion. The second overdose involved atenolol. Although the blood levels reported were very high, the patient showed no cardiovascular compromise and required only inhaled bronchodilators for an exacerbation of her asthma.

Adolescent↗
PubMed1985

Model of experimental chronic osteomyelitis in rats.

We describe here a Sprague-Dawley rat model for chronic osteomyelitis. Staphylococcus aureus and sodium morrhuate were implanted by either microdrilling or direct needle injection into the tibiae of rats. Of 107 rats, 87 (81%) developed osteomyelitis when a high-speed drill was used for implantation, and 27 (51%) of 53 rats developed osteomyelitis by direct needle inoculation (chi square = 9.81, P less than 0.01). Demonstrated histopathological changes included the presence of resorption bays filled with osteoclasts. Quantitative microbiological monitoring of tibial count confirmed disease chronicity, yielding stable numbers of CFU (10(6.29 +/- 0.27) ) of S. aureus over 70 days. Infected animals became anemic and lost weight. The erythrocyte sedimentation rates and leukocyte counts were not elevated. Roentgenograms provided the best correlation with the number of organisms in infected tibiae (r2 = 0.80). Rats with infected tibiae were treated with either oxacillin (120 mg/kg per day) or ceftriaxone (50 mg/kg per day). Treatment over 14 or 28 days reduced S. aureus counts in tibiae but did not reliably sterilize infected bones, suggesting that this model was resistant to prolonged antimicrobial therapy.

Animals↗
PubMed1985

Surface charge distribution in normal and transformed rat bladder epithelial cells in vitro.

Cationized ferritin (CF) was used as an ultrastructural marker to study differences in the distribution and density of surface anionic charges between normal and neoplastic cells. In anchorage-independent cell systems, CF induces a redistribution of cell surface receptor-ligand complexes into clusters, patches, and caps on the surfaces of transformed cells, but not on the surfaces of normal cells. In the present report, the authors have, for the first time, extended the CF labeling studies to a system of anchorage-dependent, rat bladder epithelial cell lines: normal RBTC cells and RBTCC-8 carcinoma cells. Cells were grown to confluency and labeled with 500 micrograms/ml CF for 3 minutes. After completion of CF labeling, cells were incubated for 0, 15, 60, 120 minutes, or overnight and were fixed then with buffered glutaraldehyde for electron microscopy. The results show that (a) CF induces grouping of surface anionic charge sites into patches and clusters on RBTCC-8 carcinoma cells (CF covers 53.86 +/- 2.15% of the plasma membrane), but not on normal RBTC cells (CF covers the entire plasma membrane); (b) CF densities are well correlated to the cell surface sialic acid contents of RBTC (2.42 +/- 0.30 microM/10(9) cells) and RBTCC-8 cells (1.26 +/- 0.25 microM/10(9) cells); and (c) CF-labeled membrane is internalized at equal rates by RBTC and RBTCC-8 cells (30% in 15 minutes; 60% in 60 minutes; 70% in 120 minutes; 100% overnight). These data indicate that CF-induced patching of anionic sites is a surface characteristic that is common to anchorage-dependent and independent tumor cells. Mechanisms of CF patching in neoplastic cells are discussed.

Animals↗
PubMed1985

Pathology of superficial bladder cancer with emphasis on carcinoma in situ.

The coexistence of carcinoma in situ in flat epithelium adjacent to tumors is prognostically significant and is associated with an increased incidence of tumor recurrence and invasion. Recent investigations have been aimed at finding markers that will help identify flat areas of dysplasia or low-grade papillary transitional cell carcinomas that have a high potential to evolve into invasive tumors. Both DNA and karyotype analyses, as well as cell surface markers, have been examined in some detail and could have clinical value in certain settings. The tumor DNA index as measured by flow cytometry of nuclei retrieved from deparaffined sections may be particularly useful as a predictor of tumor recurrences and, possibly, tumor invasion as well. The diagnosis of superficial disease rests on urine cytology and the histopathologic assessment of tissue biopsies; however, intra- and inter-observer reproducibility of tissue and cytologic diagnoses by pathologists is a significant problem. The application of new technologies, such as flow cytometric analysis of deparaffined nuclei, may reduce the subjectivity involved in the light microscopic assessment of pathology specimens.

Adenocarcinoma↗
PubMed1985

Flow cytometric analysis of heterogeneity in blood group-related antigen expression in a human urinary bladder carcinoma cell line, 647V.

Previous immunohistological studies showed a relationship between expression of blood group-related antigens (BG-Ag) and invasive potential in human urinary bladder carcinoma, but the marked variability of antigen staining within many individual tumors has obscured the biological basis of this finding. We studied the expression of the A, H, and T (Thomsen-Friedenreich) BG-Ag by flow cytometry in a human bladder carcinoma cell line (647V) using fluoresceinated BG-Ag-specific lectins (Dolichos bifloris, Ulex europaeus, and Arachis hypogaea). Cell cycle compartments were quantitated by flow cytometry using propidium iodide staining. Expression of all three antigens was highly variable, but staining for each antigen produced a distinct profile. T antigen expression appeared independent of A or H antigen expression. Cell populations sorted by T antigen expression showed heritable antigenic differences persistent over many weeks in culture. However, much of the T antigen variability was nonheritable, since the stable staining profiles of the sorted cells were intermediate between the parental and the profiles obtained immediately after sorting. The nonheritable antigenic variation did not appear entirely explainable by cell size or cell cycle fluctuation. These results were confirmed by isolating 64 clones from the dim part of the T antigen staining profile, 19 of which had a persistently dim phenotype. The variability of BG-Ag expression by human bladder carcinoma cells in vitro may explain the staining patterns observed in the study of antigen expression in resected human bladder carcinomas.

ABO Blood-Group System↗
PubMed1984

Interaction of chlorpromazine with the human erythrocyte membrane.

The interaction of the amphipath chlorpromazine (CPZ) with the human erythrocyte membrane was evaluated. The partition coefficient of CPZ between the membrane bilayer and the aqueous compartment, measured spectrophotometrically, ranged between 1 and 3 X 10(3). An independent estimate, 4.6 X 10(3), was obtained by a novel method which avoided the measurement of binding and determined instead the variation of the hemolytic potency of the amphipath with the ratio of buffer volume to membrane volume. The maximal uptake of CPZ exceeded 2 X 10(9) molecules/red cell, corresponding to a volume greater than that of the bilayer itself. Such heavily loaded membranes were increased in thickness more than 2-fold, suggesting the formation of a CPZ-rich zone at the center of the bilayer. Ghosts loaded with massive levels of CPZ condensed approximately 20-fold in surface area and increased proportionately in thickness, suggesting the formation of a novel CPZ-lipid solution. CPZ caused hemolysis by a colloid-osmotic mechanism. By measuring the simultaneous uptake of mannitol and sucrose, we determined that CPZ induced holes of constant size but variable number. If circular, the holes would have had a diameter of approximately 14 A. The time-averaged number of holes ranged from 0.09 per cell (signifying intermittency) to 16. Freeze-fracture electron microscopy of CPZ-treated red cells revealed multiple round patches of nearly particle-free bilayer up to 0.3 micron in diameter with crowding of the intramembrane particles into the surrounding membrane. We interpret these images to signify lateral phase separation within the CPZ-treated bilayer. Hemolysis could, therefore, result from the intermittent opening of weak seams at phase boundaries; these could then be fluctuating slits approximately 14 A in width and of variable length, rather than simple circular holes.

Biological Transport↗
PubMed1984

Bone histomorphometry in vitamin D-deficient rats infused with calcium and phosphorus.

Defective mineralization of bone and cartilage is the classical histological finding in vitamin D deficiency. Whether this represents a direct effect on mineral deposition or is a consequence of the decreased calcium and phosphorus levels that result from impaired intestinal absorption is not clear. A method has been developed in which vitamin D-deficient rats have plasma calcium and phosphorus levels maintained in the normal range by continuous infusion. Histomorphometric analysis of undecalcified tibiae from these animals was compared with that of rats given vitamin D. Epiphyseal growth plate thickness, trabecular osteoid volume, and mean osteoid seam width were not increased. Moreover, the administration of two time-spaced courses of tetracycline revealed that the mineralization rate and the time interval between apposition and subsequent mineralization of osteoid (mineralization lag time) were identical to those in rats treated with vitamin D. Trabecular bone volume was increased (osteosclerosis) in the vitamin D-deficient rats. In vitamin D-deficient controls without infusions, the osteosclerosis was mostly osteoid, whereas the excess bone was well mineralized in the vitamin D-deficient rats infused with calcium and phosphorus. Osteosclerosis in vitamin D-deficient animals may result from both decreased bone resorption and increased osteoid apposition. This study provides firm evidence that vitamin D is not essential for mineralization in young growing rats. Decreased availability of calcium and phosphorus thus may be the sole basis of the mineralization defect seen in vitamin D deficiency.

Animals↗
PubMed1984

Decreased serum ionized calcium and normal vitamin D metabolite levels with anticonvulsant drug treatment.

Alterations in vitamin D metabolism are generally thought to account for the hypocalcemia and osteopenia caused by long term treatment with anticonvulsant drugs. Regional variation in the incidence and severity of anticonvulsant drug-induced bone disease has been attributed to differences in sunlight exposure, with most reports coming from areas with limited sunshine or from institutionalized patients. Serum ionized calcium levels in 109 ambulatory adult epileptic outpatients receiving chronic anticonvulsant drug therapy in Georgia were decreased [4.73 +/- 0.02 (+/-SE) vs. 4.97 +/- 0.01 mg/dl; P less than 0.001). Immunoreactive PTH concentrations were increased (5.5 +/- 0.4 vs. 4.0 +/- 0.3 microliterEq /ml; P less than 0.005), while bone mineral content was reduced, averaging only 88.8% of the predicted normal values. Hypocalcemia and osteopenia occurred in spite of normal mean levels of serum 25-hydroxyvitamin D and 1,25-dihydroxy-vitamin D. The indirect relationship between serum concentrations of antiepileptic drugs and the serum ionized calcium level, and the lack of correlation with vitamin D metabolite levels suggested that hypocalcemia was independent of the effect of the drugs on vitamin D metabolism. Bone biopsies revealed increased osteoid but normal calcification front formation, accelerated mineralization rate, and decreased mineralization lag time indicative of increased skeletal turnover, rather than osteomalacia.

Adult↗