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Biomedical subjects

B L Shapiro

Publications and source records attributed to B L Shapiro.

At least 19 recordsLinked to original sources
PubMed1990

Bioregulatory mechanisms at the level of cell organelle interactions: microspectrofluorometric in situ studies.

The spatiotemporal analysis of bioregulatory mechanisms at the level of intracellular multienzyme complexes and organelle interactions is made possible by the availability of endogenous and exogenous fluorescence probes, the development of microspectrofluorometers allowing one- and two-dimensional scans of intracellular fluorescence reactions, and the use of micromanipulatory techniques enabling the rapid alteration of metabolic states. Absorbed photons are not only a tool for quantitative evaluation of metabolic processes, they can also trigger alterations of cell membranes and functions as mediated by photosensitizer drugs. In the hierarchy of intracellular organization different levels of complexity are accessible to study, such as the regulation of multienzyme complexes and the interaction of organelle complexes. Typical applications of these methods are the investigation of drug effects (e.g., on melanoma cells), metabolic and structural alterations (e.g., in cystic fibrosis and Gaucher fibroblasts), organelle interactions in cells treated with toxic agents. The implications are relevant to biotechnology for better control of metabolite production and processing, design and testing of new drugs, understanding of drug resistance and better targeting of drugs or probes to selected intracellular sites. In addition, such in vitro methods can contribute to the provision of an alternative to "whole animal experiments" as already achieved in human and mouse fibroblasts, hepatocytes, hepatoma, Swiss 3T3 cells and other cells in culture, especially with regards to an analysis of the action of xenobiotics and drugs in cell physiology and pathology, fluorescence recovery after photobleaching, study of cytoskeleton dynamics and multiparameter probing of organelle activity during in vitro wound repair.

Animals↗
PubMed1990

The prevalence and treatment needs of subjects with temporomandibular disorders.

A cross-sectional study of prevalence of temporomandibular joint (TMJ) internal derangements, muscle disorders, and associated TM signs and symptoms was completed on 269 female nursing students. The prevalence of specific stages of internal derangements of the TMJ and muscle disorders was estimated, using established diagnostic criteria. The levels of dysfunction and symptomatology associated with each diagnosis were estimated with previously established indexes. When subjects with symptoms were asked if they had previous treatment for a TMJ problem, 6.7% responded positively. When subjects with symptoms who had not had treatment were asked why they had not sought treatment, most responded that it was not a problem or they could live with the symptoms. Thus, most subjects with clinically detectable dysfunction are functioning adequately without significant symptoms and do not need treatment.

Adult↗
PubMed1989

Evidence for a mitochondrial lesion in cystic fibrosis.

Cystic fibrosis (CF) remains a major problem in human genetics and cell pathophysiology. It is a single gene trait caused by a mutation on the long arm of chromosome 7. Among its expressions are abnormal regulation of chloride channels and/or microobstructions in exocrine tissues. Here, evidence is presented that mitochondria are dysfunctional in CF: the major site of increased intracellular Ca in CF is mitochondrial, cells from subjects with CF consume more oxygen than normal, respond differentially to inhibitors of mitochondrial function, express increased electron transport activity and altered kinetics of complex I (NADH dehydrogenase) of the mitochondrial electron transport system. Patients with CF express increased total and resting energy expenditure. Some of these differences from normal occur also in asymptomatic carriers of the CF gene.

Calcium↗
PubMed1987

Intracellular calcium in cystic fibrosis heterozygotes.

Increased intracellular calcium (Ca) has been reported in several cell types in cystic fibrosis (CF). Because CF is an autosomal recessive trait examination of asymptomatic obligate carriers (HZ) of the gene is a powerful way to determine the relevance of this observation to the abnormal gene product. We report here that Ca as determined by atomic absorption spectrophotometry in cultured skin fibroblasts and circulating lymphocytes is greater in HZ than in control cells. Since an intracellular Ca increase is expressed in HZ the Ca differences in CF likely reflect action of the gene product responsible for CF and not some secondary or tertiary effect of the disease.

Calcium↗
PubMed1984

Competitive inhibition of human mitochondrial NADH dehydrogenase by Cibacron Blue F3GA.

Cibacron Blue F3GA, the chromophore of blue dextran, was tested at 4-16 mumol/l for possible inhibition of NADH dehydrogenase activity when added to mitochondrial preparations from cultured human skin fibroblasts. The free dye was shown to be a competitive inhibitor for NADH in the oxidation of NADH catalyzed by the mitochondrial enzyme. The Ki (5.8 mumol/l) for Cibacron Blue F3GA was considerably lower than the Michaelis constant (Km) found for NADH substrate (13.2-16.1 mumol/l), indicating a strong binding of the dye to the substrate-binding site of the enzyme. This is the first report of the competitive inhibition by Cibacron Blue F3GA of mitochondrial NADH in any species.

Binding, Competitive↗
PubMed1983

Down syndrome--a disruption of homeostasis.

A major question in human genetics concerns the relationship between the extra chromosome material in the Down syndrome (DS) and its effects. It is suggested here that a generalized disruption of evolved genetic balance in cells of affected individuals leads to decreased developmental and physiological buffering against genetic and environmental forces. Examples of consequences in DS of this model of disruption of homeostasis are presented: i) increased variance for metric traits, ii) amplified instability of developmental pathways, iii) reduced precision of physiological homeostatic controls, and iv) generalized increased morbidity. Evolution has selected for interacting systems. When this evolved balance is disrupted, as in autosomal aneuploidy, the organism is generally disrupted. The model emphasizes the role of environment in producing much of the DS phenotype. Traits less buffered than others in the general population are the ones most disturbed in DS and account for much of the DS phenotype.

Blood Glucose↗
PubMed1982

Calcium and age in fibroblasts from control subjects and patients with cystic fibrosis.

Intracellular calcium increases significantly as human fibroblasts age in culture. The calcium increase occurs 5 to 6 weeks (passages) earlier and is significantly greater in fibroblasts from subjects with cystic fibrosis in comparison with cells from control subjects. Intracellular calcium, which is thought to be a pathogenetic factor in cystic fibrosis, may also be a meaningful marker in cell aging.

Adolescent↗
PubMed1982

The calcium abnormality in cystic fibrosis mitochondria: relative role of respiration and ATP hydrolysis.

Calcium uptake by mitochondria isolated from skin fibroblasts of patients with cystic fibrosis and controls was studied in the presence and absence of inhibitors. Since mitochondrial calcium accumulation may be supported by ATP hydrolysis or respiration, inhibitors of each were used to characterize the basis of previously described alterations in calcium uptake by mitochondria from patients with cystic fibrosis. Calcium uptake measurements under the influence of oligomycin and antimycin A suggest that the increased calcium uptake by mitochondria from patients with cystic fibrosis is related to altered respiratory system activity. Binding constants of calcium to the carrier system in mitochondria were not different between genotypes.

Adenosine Triphosphate↗
PubMed1982

Mitochondrial NADH dehydrogenase in cystic fibrosis: enzyme kinetics in cultured fibroblasts.

Differences among cystic fibrosis (CF) genotypes (CF, obligate carriers for CF [HZ], and controls) in mitochondrial calcium pool size, oxygen (O2) consumption, and rotenone inhibition of O2 consumption led to examination of mitochondrial NADH dehydrogenase (NADH: [acceptor] oxidoreductase, E.C. 1.6.99.3). pH optima of mitochondrial NADH dehydrogenase were different in enzyme derived from whole cell homogenates of cultured skin fibroblasts of subjects with CF, HZ, and controls. We describe here apparent binding of substrate to the enzyme (Km [NADH]) in cell fractions. Km (NADH) for CF ranged from 10.9 to 16.1 micro M (no. = 7); for HZ from 20.9 to 26.3 microM (no. = 5). With three exceptions, Km for controls (no. = 12) ranged from 31.8 to 42.8 microM. Km of the three exceptional controls were 21.5, 23.7, and 22.4 microM (the latter two are identical twins). pH optima of enzyme from these three strains were no different from that of known HZ. The correlation between two kinetic parameters of an enzyme and the three CF genotypes suggests an association between the CF gene and mitochondrial NADH dehydrogenase.

Adolescent↗
PubMed1981

One to one correlation of histological and histochemical light microscopy with scanning electron microscopy.

Several histological stains were applied to specimens after scanning electron microscopic (SEM) processing. Histochemical stains were applied before SEM fixation. After staining, the specimens were processed and dried by SEM techniques. The specimens were taped to a microslide, specimen side up, scribed and covered with immersion oil. After light micrography (LM), the oil was removed and the specimens mounted and gold coated. The same cells were then relocated and photographed by SEM. Periodic acid Schiff was not usable as a specific tissue aldehyde stain, but did prove to be a useful counterstain for dehydrogenase stained specimens. Colloidal iron, as seen by SEM, resulted in a non-specific granular deposit over the specimen and the substrate. All the other histological stains examined--alcian blue, Grams, Feulgen and toluidine blue--were specific and did not change the specimen ultrastructure. The histochemical stains--acid and alkaline phosphatase and three dehydrogenases--were also specific. There were some minor ultrastructural changes with the AcPase and AlPase stains. However, the tissue surface was not significantly distorted. These and other techniques should prove to be a useful adjunct to SEM studies.

Amniotic Fluid↗
PubMed1980

The effect of alloxan diabetes and insulin on the rate of protein synthesis in the rat submandibular gland.

The incorporation of radioactively labeled leucine into TCA-precipitable proteins by submandibular gland tissue slices from control, alloxan diabetic, and insulin supplemented diabetic rats was measured in vitro. Incorporation decreased in alloxan diabetes and could be restored to control levels within three hours after insulin administration. The effects of alloxan diabetes and insulin on 3H-leucine incorporation paralleled their effects on a secretory enzyme, peroxidase. Insulin in vitro stimulated the incorporation of 3H-leucine within 15 minutes of addition to the incubation medium. Further, the response to insulin was found to be dose-related. The conclusion drawn from these results is that insulin has a rapid, direct effect on the rate of protein synthesis in the rat submandibular gland.

Animals↗