Alvin Telser

A sodium dodecyl sulfate-polyacrylamide gel electrophoresis system that separates peptides and proteins in the molecular weight range of 2500 to 90,000☆

A discontinuous sodium dodecyl sulfate-polyacrylamide slab gel electrophoresis system is described which provides superior resolution of polypeptides with molecular weights from approximately 2500 to 90,000. The system utilizes a relatively low-mobility acetate ion in the stacking gel and high-mobility strong anions, sulfate and chloride, as leading and trailing ions in the separating gel. The entire system is run at pH 7.8. The separating gel contains 8 M urea, and can be used at acrylamide concentrations from 5 to 18%, all with 5% crosslinker concentrations. Using a number of protein standards, the calibration curves obtained with this system are linear over the molecular weight range from 2500 to 90,000, regardless of acrylamide concentration. These studies indicate that by providing good resolution of small peptides, this system greatly extends the utility of one-dimensional peptide mapping techniques.

Semiquantitative determination of cyanogen bromide peptides of collagen in SDS-polyacrylamide gels

The application of staining with Coomassie brilliant blue in isopropanol acetic acid to the quantitation of cyanogen bromide peptides of collagen on electrophoresis in SDS-polyacrylamide gels was evaluated. A linear relationship between stain uptake and weight of peptide material loaded onto the gel was demonstrated over the range investigated (up to 40 μg of total mixture of peptides) for each component resolved. The larger peptides (≥18,000 MW) could be quantitated either as individual components or as a proportion of the total mixture to a precision of ±15% or better on quantities of 1 μg or less per band.

Silicone Occlusive Treatment of Hypertrophic Scar in the Rabbit Model

BACKGROUND Hypertrophic scar formation at sites of healed cutaneous injury often produces functional and esthetic deficits. Treatments have been limited in part by a lack of understanding of scar etiology and the lack of animal models of hypertrophic scarring. Silicone dressing is reported to provide positive outcomes with respect to a reduction in scar hypertrophy and an improvement in color differences, although the exact mechanism is unknown. OBJECTIVE We tested the effectiveness of silicone adhesive gel in the reduction of scar hypertrophy in an animal model of scarring. METHODS Silicone adhesive gel was applied to scars in a rabbit ear model of hypertrophic scarring. Scarring in this model, which displays reduced hypertrophy in response to steroid injections and aging similar to that of human beings, was measured by the Scar Elevation Index (SEI), a ratio of the scar height over normal skin, in which readings greater than 1.0 represent a raised scar. RESULTS SEIs were significantly reduced after 4-week applications of silicone gel (1.15 +/- 0.15 vs 1.71 +/- 0.33, respectively; P < .001) versus untreated scars. Nonsilicone control dressings did not alter SEIs in comparison with those found for controls. No histologic differences in scar cellularity, inflammation, or matrix organization were found between treatment groups; however, ultrastructural observation revealed numerous vacuoles in basal cells of control and nonsilicone-treated scars that were not found in unwounded skin or silicone gel-treated scars. The similarity in water vapor transmission rates for silicone gel and a nonsilicone dressing eliminated scar hydration as the sole mechanism of action of the silicone dressings. CONCLUSIONS Our findings with the rabbit model demonstrate the effectiveness of silicone gel for hypertrophic scar treatment and confirm the usefulness of this model for further study of the mechanism of occlusion. (Aesthetic Surg J 2002;22:147-153.).

Diminished axonal transport of glycoproteins in the senescent rat brain.

At various time intervals (10, 15, 20, 25, 30 min) after injection of 3H-fucose into the medial septal nucleus of young adult (3 months old) and senescent (25 months old) Fischer-344 rats, the specific activities of trichloroacetic acid-phosphotungstic acid (TCA-PTA) soluble and insoluble fractions were determined in the medial area of the septum and in three successive rostro-caudal sections of the hippocampal formation containing mainly the dentate gyrus, but also its hilus with fields CA4 and CA3c of the hippocampus. The rate of 3H-fucose incorporation into glycoproteins of the septum did not differ in young adult and senescent rats. Part of the TCA-PTA soluble and insoluble radioactive material was transported through the septo-hippocampal pathway to the dentate gyrus. This transport was inhibited by the injection of colchicine into the septum prior to 3H-fucose injection and was completely blocked by electrolytic lesion of the medial septal nucleus. The arrival time and the amount of the TCA-PTA soluble radioactive material transported to the dentate gyrus did not differ in young adult and senescent rats. However, the TCA-PTA insoluble labelled glycoprotein was transported to the dentate gyrus in a significantly smaller amount and during a longer period of time in the senescent animals. This age-related change may reflect a reduction in amount and/or in rate of axonal transport of glycoproteins in the septo-hippocampal pathway of senescent rats.

Development of a measure of attitude toward nutrition in patient care

BACKGROUND Development of reliable measures of medical student and resident attitudes about nutrition in patient care is needed before the effects of educational interventions or clinical experience can be gauged. This report describes the systematic development of a measure of attitude toward nutrition in patient care. It presents evidence about scale reliability and the absence of response bias that endorses the trustworthiness of data from the measure. METHODS An eight-step attitude scale development procedure was used to create the Nutrition In Patient care Survey (NIPS). Data from five samples of first- and second-year medical students and first-year medical residents were subjected to factor analysis (PA2, varimax rotation), reliability analyses, and statistical analyses to test for demographic bias in the attitude data. RESULTS A 45-item attitude measure was developed that contains five subscales derived from the factor analysis: (1) nutrition in routine care (NRC, 8 items); (2) clinical behavior (CB, 20 items); (3) physician-patient relationship (PPR, 8 items); (4) patient behavior/motivation (PBM, 3 items); and (5) physician efficacy (PE, 6 items). Each subscale yields reliable data in terms of internal consistency (alpha coefficients) and stability (test-retest reliability). Medical student and resident demographic variables have negligible influence on attitude scores. DISCUSSION The NIPS subscales yield reliable data that can be used to assess outcomes in evaluation research on educational or clinical interventions or to predict patient care practices. Systematic attitude scale development increases the likelihood that the resulting measures will produce useful, trustworthy data.

Immunohistochemical localization of a low molecular weight, soluble protein from bovine lingual epithelium.

SummaryA low molecular weight (LMW) protein was isolated from bovine tongue epithelium and an antiserum to this protein elicited in rabbits. The indirect peroxidase-antiperoxidase (PAP) technique was used to localize LMW protein in several tissues from six mammalian species: cow, rat, mouse, squirrel, rabbit, and man. Immunoreactivity was demonstrable in stratified squamous epithelia from skin, tongue, cheek, esophagus, vagina, and palate. Epidermal derivatives, such as hair follicles, sebaceous glands and ducts of certain glands were also positively stained. Cornea exhibited weak immunoreactivity as did rabbit bladder. Other types of epithelia including those seen in kidney, thyroid, intestine, trachea, liver, submandibular gland, pancreas and uterus, were not immunoreactive when tested with antiserum to LMW protein. The antiserum was rendered unreactive after absorption with LMW protein but, when absorbed with a keratin polypeptide, most of the immunoreactivity was preserved. It is concluded that the distribution of the soluble LMW protein is similar to that of the insoluble keratin proteins in stratified squamous epithelia but the former is not demonstrable in many simple epithelia that contain keratins

A specific stain for sulfhydryl groups in proteins after separation by polyacrylamide gel electrophoresis

A new method is described for specifically staining protein sulfhydryl groups after the proteins have been separated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis in slab gels. The stain will detect as little as 0.25 microgram of lysozyme and 1 microgram of most other proteins; the range of sensitivity for a specific protein depending on its sulfhydryl content. Proteins with no cysteine residues (type I collagen) and glycoproteins do not cause spurious staining.