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Biomedical subjects

G S Wilson

Publications and source records attributed to G S Wilson.

At least 73 records · Page 4Linked to original sources
PubMed1990

Effect of H2O2 concentration and exposure time on stromal swelling: an epithelial perfusion model.

The corneal epithelium can be affected adversely by some preservatives used in contact lens solutions. To test the effect of H2O2 at the epithelial surface, the rabbit cornea was perfused with various concentrations of H2O2, and the effect on stromal and Anterior Bright Band (ABB) thickness measured for 150 min. The study compares stromal swelling and ABB swelling for a single 10-min pulse with that for a 150-min sustained dose. With the 10-min pulse dose there was no significant swelling up to 235 ppm H2O2, the highest dose tested. With the sustained dose, significant stromal swelling began between 72 and 153 ppm H2O2. These results indicate that residual H2O2 present at the epithelial surface after neutralization in current contact lens disinfection systems does not have a high enough concentration to affect corneal function adversely.

Animals↗
PubMed1990

An exploratory study of the structure and validity of pediatric examination of educational readiness (PEER) factors.

The Pediatric Examination of Educational Readiness (PEER) is an assessment instrument specifically designed for use by pediatricians in assessing the development of preschool children. The present study investigated the psychometric properties of the PEER. Specifically, factor analyses of items from the Developmental Attainment and Associated Observation components of the test were performed. The PEER was administered to 69 preschool children. Three major factors were identified as making up the Developmental Attainment portion of the test: perceptual-motor, verbal-cognitive, and gross motor. The Associated Observations component was found to be composed of only one factor, attention. Children's performance on only two of these four factors was associated with their performance on the McCarthy Scales, the Woodcock-Johnson skills cluster, and the Minnesota Child Development Inventory. Discussion focused on the validity and utility of the PEER.

Attention↗
PubMed1990

Nonhandicapped very-low-birth-weight infants at one year of age: developmental profile.

The developmental profile of 61 very-low-birth-weight infants without major cognitive, motor, or sensory deficits was compared with that of 28 term infants at 1 year chronologic age. The groups significantly differed in two ways on the Revised Gesell Developmental Schedules. First, very-low-birth-weight infants were more likely than term infants to have significant discrepancies between either their fine motor or language abilities and their early problem-solving skills as measured by the Adaptive scale of the Gesell. Second, across all fields of behavior (adaptive, gross motor, fine motor, language, and personal/social), very-low-birth-weight infants scored significantly below term infants. The very-low-birth-weight infant's motor performance significantly correlated with bronchopulmonary dysplasia, intracranial hemorrhage, and number of days spent in the hospital. Language performance significantly correlated with intracranial hemorrhage, birth weight, and sex. These findings underscore the limitations of global developmental scores to describe adequately the developmental performance of very-low-birth-weight infants. Instead, a comprehensive assessment of all fields of behavior is necessary to provide an accurate profile of this high-risk group.

Bronchopulmonary Dysplasia↗
PubMed1989

Pulsed amperometric detection of glucose in biological fluids at a surface-modified gold electrode.

A nonenzymatic glucose sensor that utilizes permselective membranes to achieve the selectivity required for screening glucose in biological fluids has been described. Interference from endogenous oxidizable substances such as amino acids, urea, ascorbic acid, and uric acid, as well as the effect of chloride and proteins on glucose response, is studied by using flow injection analysis. A set of membranes made of Naflin perfluorinated membrane and collagen, when arranged in front of the working electrode (gold), result in significant improvement in the system selectivity. Even at physiological pH, which is far from being the optimum pH for pulsed amperometric detection of carbohydrates, the sensor shows a good limit of detection (4-5 micrograms of glucose injected).

Acetaminophen↗
PubMed1989

Study and development of multilayer needle-type enzyme-based glucose microsensors.

Glucose oxidase (GOD) was covalently coupled to a cellulose acetate (CA) layer, using bovine serum albumin (BSA) and parabenzoquinone (PBQ) linkages. Prior to GOD coupling this CA layer was deposited on the platinum tip of a needle-type sensor and covered with an outer layer of polyurethane (PU). Such microsensors were found to be active, their GOD load reaching 1.6 to 3.0 micrograms mm-2 and their glucose response reaching 1 to 3 microA M-1 mm-2, even when the upper limit of their linear range reached 10-30 mM. Due to the multilayer structure and composition of these microsensors, small anions such as ascorbate were partially discriminated from neutral molecules such as hydrogen peroxide. When implanted subcutaneously in anaesthetized rats, sensor responses correlated correctly with blood glucose concentration but presented sensitivity coefficients significantly different to those determined in vitro: a 2 point calibration procedure was found necessary for in vivo experiments.

Animals↗
PubMed1989

Ultrastructural effects of sodium chloride on the corneal epithelium.

Ten excised rabbit corneas were bathed posteriorly with glutathione bicarbonate Ringers solution (GBR), while anteriorly the bathing solution was either GBR or sodium chloride solution (NaCl). All solutions had an osmolarity of 305 +/- 2 mOsm/kg. The corneas were fixed after 150 min exposure to the solutions, and prepared for electron microscopy. Morphometric analysis of the electron micrographs was conducted by an observer unaware of the anterior bathing solution. In each case, the epithelium was examined along a 1500 micron stretch of the basement membrane. Cells were categorized as normal, abnormal, and sloughing. Abnormal cells showed cytoplasmic and nuclear pallor, and disrupted cell membranes. Sloughing cells showed partial separation from the underlying epithelium. Corneas exposed to NaCl showed statistically significant differences from those exposed to GBR; the differences occurred in both the number of abnormal cells, and the number of sloughing cells. All observed ultrastructural changes were limited to the surface region of the epithelium. It is concluded that sodium chloride solution is inadequate at maintaining the epithelial surface.

Animals↗
PubMed1988

Cytochrome c: ion binding and redox properties. Studies on ferri and ferro forms of horse, bovine, and tuna cytochrome c.

The ion binding properties of horse, bovine, and tuna cytochrome c (both oxidized and reduced) have been measured using a combination of ultrafiltration, neutron activation, and ion chromatography. The ions investigated were chloride, phosphate, and Tris-cacodylate. Ion chromatography and neutron activation analysis techniques were employed to determine the concentration of free anions. Binding constants are obtained from modified Scatchard plots (in the range of 10-2000 M-1). The redox potentials for cytochrome c at different ionic strengths, pH 7.0, have been determined. In this paper we report the ionic strength and ion binding effects on the redox properties of horse, bovine, and tuna cytochrome c. Potential versus ionic strength dependence for horse, bovine, and tuna cytochrome c from the experimental data were compared with a theoretical model.

Animals↗
PubMed1987

Characterization of adsorption on the stationary phase using high-performance immunoaffinity chromatography.

Low-level adsorption on the stationary phase has been studied using immunochemical reagents. An immunoaffinity column has been evaluated using affinity-purified radioisotope-labeled monoclonal antibodies. Recovery experiments including continuous immunosorbent monitoring have been performed. Proper characterization of an immunoaffinity separation can result in the recovery of immunologically active material in high yield.

Adsorption↗
PubMed1987

Neurodevelopmental status of low birth weight infants with bronchopulmonary dysplasia requiring prolonged oxygen supplementation.

Fifty infants weighing 1,500 g or less at birth with a diagnosis of bronchopulmonary dysplasia (BPD) were followed to a mean age of 25 months to determine their clinical course and short-term neurodevelopmental outcome after discharge from the Neonatal Intensive Care Unit, and to identify possible predictive factors for outcome. Because study participation was voluntary, the subjects may not have represented the total population of BPD survivors. Occurrences of abnormalities were high: 11 hearing impaired, 10 legally blind, 14 cerebral palsy, and 23 abnormal development scores. Twenty-one subjects had feeding problems and weight was below the fifth percentile in 26. Home-oxygen therapy was required by 50 per cent of the subjects. Although severity of illness, duration of oxygen therapy and feeding problems were greater among those sent home on oxygen, their neurodevelopmental status did not differ from that of infants breathing room air by discharge. Factors associated with neurodevelopmental outcome were intracranial hemorrhage, pulmonary air leak, and length of hospital stay.

Bronchopulmonary Dysplasia↗
PubMed1987

Delineation of a novel pre-B cell component in plasma cell myeloma: immunochemical, immunophenotypic, genotypic, cytologic, cell culture, and kinetic features.

A novel pre-B cell component in direct and cultured myeloma bone marrow material has been delineated by using immunochemistry and flow cytometry techniques. Our phenotypic studies suggest a novel hybrid expression of pre-B and plasma cell antigens with coexpression of cytoplasmic mu, common acute lymphoblastic leukemia antigen, terminal deoxynucleotidyl transferase, and plasma cell antigens (PCA-1 and PC-1). This suggests that myeloma pre-B-like cells are aberrant malignant cells and not normal pre-B lymphocytic counterparts. With the advantage of a pure and stable source of these cells from M3 culture to allow molecular characterization, we performed one- and two-dimensional gel electrophoresis and Western blotting. We found that the cytoplasmic mu in myeloma pre-B-like cells has a molecular weight of 74,000 daltons and an isoelectric point of 6.3 and that it is strikingly homogeneous and discrete in size and charge compared with standard secretory mu, which suggests an aberrant, mutant, or monoclonal form of mu. Monoclonality was further evidenced by heavy- and light-chain immunoglobulin gene rearrangements demonstrated with JH and C kappa probes. We also established that this novel myeloma pre-B component is a major proliferative element as determined by double-labeling experiments with phenotype coupled to labeling/proliferative indexes. Our stimulatory studies indicate some capacity of these cells to mature on exposure to phorbol esters. These myeloma pre-B cells may represent the stem cell or self-renewal component in myeloma. Our establishment of these cells in long-term culture offers a considerable asset in studying the immature cells, which may be critical to the immortalization of myeloma.

B-Lymphocytes↗
PubMed1986

Investigation of sloughed corneal epithelial cells collected by non-invasive irrigation of the corneal surface.

This paper reports the development of a non-contact corneal irrigation chamber (NC-CIC) which enables non-invasive collection of epithelial cells from the corneal surface of human subjects. Cells were viewed by fluorescence microscopy following vital staining with acridine orange (AO). Staining characteristics revealed two corneal epithelial cell types: cells with (i) green and (ii) orange-red cytoplasmic staining. The green cytoplasmic stain appeared to indicate a more viable cell. Multi-cell aggregates were regularly collected from the corneal epithelial surface. Groups of up to seven epithelial cells were obtained. Quantitative studies of corneal epithelial cell sloughing, using isotonic NaCl (305 mOsm/kg) and isotonic "basic tear solution" (BTS, 305 mOsm/kg) as irrigating solutions, involving hourly irrigations between 8 a.m. and 4 p.m. were conducted. Consistently higher cell counts were obtained with NaCl. Using BTS, data scatter was reduced sufficiently to reveal significant differences in sloughing rate as a function of time of day. Instillation of one drop of 0.5% proparacaine caused a significant, but gradual, increase in epithelial cell sloughing rate over a period of hours, as indicated by subsequent BTS irrigations of the cornea. Since the NC-CIC technique is able to discriminate these effects, it may be an appropriate system for in vivo studies of the relationship between corneal epithelial cell mitosis and sloughing.

Anesthesia, Local↗
PubMed1985

Needle localization of nonpalpable breast masses.

A series of 146 women underwent 150 preoperative localizations of mammographically suspicious but nonpalpable breast lesions. The lesions were localized using the hook-wire method of Frank in 133 of these patients. Carcinoma was discovered in 24 (16%) of the women; 18 (75%) of these women had invasive and six women (25%) had noninvasive carcinomas. Sixty-seven patients demonstrated calcification, and of these, 16 patients (24%) turned out to have malignancies. Eighty percent of the cancers were less than 1 cm in diameter, and 38% met the criteria of minimal carcinoma as described by Gallagher and Martin in 1969. Fourteen percent of the patients with carcinoma had lymph node metastases. We conclude that this is a safe, rapid, and accurate method for localizing small, potentially highly curable breast cancers with minimal sacrifice of breast tissue.

Adult↗