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Biomedical subjects

S Fletcher

Publications and source records attributed to S Fletcher.

At least 127 records · Page 7Linked to original sources
PubMed1985

Methods of assessing speech in relation to velopharyngeal function.

Seven speech pathologists with expertise in the evaluation of the speech of individuals with cleft palate agreed that the following parameters should be assessed: case history, oral-peripheral mechanism, articulation, and voice quality. From such information and observations the clinician should be in a position to make inferences about velopharyngeal function. If velopharyngeal function is not normal, it is mandatory that additional information about the mechanism be obtained.

Articulation Disorders↗
PubMed1985

Defect in cholesterol transport in patients receiving maintenance hemodialysis.

A defect in cholesterol transport was detected in patients with uremia who were receiving long-term hemodialysis when the rate of cholesterol transfer (RCT) from high-density lipoprotein (HDL) to very low-density (VLDL) and low-density lipoproteins (LDL) was compared with that in controls. The RCT (mean +/- SD) in 29 men with uremia (1.85 +/- 1.29 mg/hr/100 ml) and 11 women with uremia (1.84 +/- 1.00 mg/hr/100 ml) was significantly lower (P less than 0.001) than values in 55 healthy men (4.50 +/- 2.61 mg/hr/100 ml) and 23 healthy women (3.72 +/- 1.92 mg/hr/100 ml), respectively. Six patients, but none of the controls, totally lacked the ability for cholesterol transfer. The decreased RCT of the patients could not be completely accounted for by their decreased HDL cholesterol levels, because patients matched with controls for HDL cholesterol within 1 mg/100 ml also had lower RCT (P less than 0.0025). Recombination and crossover of serum fractions of patients and controls separated by ultracentrifugation revealed that the defect in cholesterol transfer of the patients was in the d greater than 1.063 gm/ml fraction (containing HDL and other serum proteins), which not only contained less HDL cholesterol, but was also qualitatively inferior as donor for cholesterol transfer. In one of four patients studied, the d less than 1.063 gm/ml fraction (VLDL and LDL) also had deficient ability to accept cholesteryl esters in the transfer. These in vitro data indicate a defect in cholesterol transport in the patients who are undergoing hemodialysis. Whether this defect exists in vivo and creates the risk of accelerated atherosclerosis warrants further study.

Adult↗
PubMed1983

On the nature of the deep cellular disturbances in human-papilloma-virus infection of the squamous cervical epithelium.

In the squamous epithelium of the cervix, disturbed deep cells, usually regarded as dysplastic, often underlie superficial koilocytes. Recognition of koilocytosis as a cytopathic effect of human papilloma virus (HPV) prompts reconsideration of the state of the deep cells, which could be non-dysplastic or dysplastic. In the dysplastic states HPV could be non-causative or causative. For dysplastic causation by HPV, a cell-differentiation hypothesis reconciles the coexistence in the epithelium of a permissive HPV infection of the superficial layers (koilocytosis) and a non-permissive cellular infection of the deep layers, which may undergo transformation to dysplasia.

Animals↗
PubMed1983

X-ray microscopy using a scanning electron microscope for the purpose of imaging central nervous system structures.

A simple modification of an Hitachi S.450 specimen stage permits point source X-ray microscopy with a scanning electron microscope. Point source X-ray microscopy was applied to nervous tissue to determine the feasibility of utilizing this technique instead of a light microscope mounted camera lucida to produce 2- and 3-dimensional images of whole structures such as neurons. Various target materials, radio-opaque materials and photographic films were examined in this study.

Animals↗
PubMed1983

Five-day storage of platelet concentrates. I. In-vitro studies.

Platelet concentrates have been prepared in standard PVC (PL-146) packs and polyolefin (PL-732) packs. Comparison of pH and hypotonic stress of the platelet concentrates has shown that significantly improved values are obtained after storage of the concentrates at 22 C in PL-732 packs for 5 days than after storage for 3 days in PL-146 packs. There was no significant difference under conditions of the test between vertical and horizontal agitation of the concentrates. Since both pH and hypotonic stress recovery have shown a relationship to post-transfusion recovery and viability, evidence is presented to support the 5-day storage period of concentrates prepared and stored in PL-732 packs.

Blood Platelets↗
PubMed1983

Histopathology of papilloma virus infection of the cervix uteri: the history, taxonomy, nomenclature and reporting of koilocytic dysplasias.

Papilloma virus infections of the squamous cervix are common and determine the incidence of koilocytes in cervical smears and biopsies. Typical exophytic condyloma acuminatum accounts for few of the infections. Most are "flat condylomata" (flat koilocytosis)--slightly raised plaques of flat profile. Superficial koilocytosis, dyskeratosis and often disturbed deep cells are their main histological features. The association between koilocytosis and dysplasia is considered and the different taxonomic approaches to the koilodysplastic states are compared. Equivalence is established between different nomenclatures by reference to the familiar dysplastic grades. Methods of reporting koilodysplasias are given and a prognostically difficult state of "full thickness" or "plenary" koilocytosis is described. In applying the "high technology" of nucleic acid hybridisation to confirm the lesion specificity of papilloma virus strains the lesions must be well defined and clearly identified by precise nomenclature: the nature and nomenclature of the lesions is critically discussed.

Adult↗
PubMed1980

Physical and dissolution characteristics and bio-availability of five brands of digoxin tablets.

Five brands of digoxin were investigated and compared for physical and dissolution characteristics and bio-availability. The dissolution characteristics, which are regarded as a measure of bio-availability in the case of digoxin, were investigated with a spectrofluorimeter. Significant differences were found among the five brands. Only one brand met all the various criteria that were investigated.

Biological Availability↗
PubMed1980

Translation of chick aortic elastin messenger ribonucleic acid. Comparison to elastin synthesis in chick aorta organ culture.

Studies were undertaken to define the molecular size of the elastin primary gene product. Translation of chick aortic messenger ribonucleic acid (mRNA) in an mRNA-dependent reticulocyte lysate resulted in the synthesis of two major proteins of 70 000 and 73 000 molecular weights. Both proteins were shown to be soluble forms of elastin by isotope incorporation, immunoprecipitation, collagenase and cyanogen bromide sensitivity, and two-dimensional gel electrophoresis. The 70 000-dalton protein behaves similarly to authentic tropoeleastin in sodium dodecyl sulfate gel electrophoresis. There was no evidence for a high molecular weight form of soluble elastin, although procollagen chains were indirectly identified among the aortic mRNA-directed translation products. The same molecular size proteins were also seen in organ cultures of chick embryonic aortas labeled with [3H]valine. However, the 73 000-dalton protein was not extractable in a neutral salt buffer but was found only if the aortas were extracted with urea in the presence of reducing and alkylating reagents. The results from these studies suggest that elastin is first synthesized as two distinct polypeptide chains which differ slightly in size and overall charge. The possibility that these two proteins may associate posttranslationally to form a dimer prior to secretion is postulated to explain the existence of a putative proelastin molecule seen in other systems.

Animals↗