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Biomedical subjects

M Phillips

Publications and source records attributed to M Phillips.

At least 343 records · Page 19Linked to original sources
PubMed1977

Long-term sweat collection using salt-impregnated pads.

To facilitate a study of the pharmacokinetics of drugs dissolved in sweat, a technique was devised for collecting sweat at a steady rate over an 8-day period. Three normal subjects each wore 4 absorbent pads applied to their skin under waterproof dressings for 8 days. The absorbent pads were either plain cotton or cotton impregnated with sodium chloride crystals. Each pad (3 cm x 3 cm) was applied to an area of skin (2 cm x 2 cm) defined by an adhesive template, and was removed daily, weighed, and replaced, to determine progressive uptake of sweat. Sweat uptake by plain cotton pads reached a plateau value within 2 to 3 days and did not significantly increase thereafter; in contrast, uptake by the salt-impregnated pads continued at a steady rate for the full 8 days of the study (mean rate 0.79 mg/cm2/hr, SD = 0.16, N = 6). This effect may be related to an osmotic gradient across the skin, but the physiologic mechanisms are not completely clear. This appears to be a convenient tool for the collection of sweat over long periods at a steady rate.

Humans↗
PubMed1977

Preparation of thin cryo-sections for electron probe analysis of calcifying cartilage.

Conventional methods of fixation, dehydration, embedding and wet-sectioning can produce artefacts in the chemical composition of mineralizing tissues. Cryoultramicrotomy was adopted for a more reliable approach to electron probe analysis of initial apatite formation in calcifying cartilage. Fresh rabbit epiphyseal cartilage was mounted on silver pins, frozen by immersion in liquid nitrogen, and sectioned with the specimen temperature at 133 K and the knife temperature at 273 K. Dry cryo-sections (30-70 nm in thickness) were manipulated on to coated grids and examined the same day. These cryo-sections showed good morphological and cytoplasmic detail, with large areas relatively free of ice-crystal damage. Sections stained either with osmium vapour or negatively stained with silicotungstic acid showed areas with well-preserved mitochondria with granules and endoplasmic reticulum. Unstained sections also showed dense granules (50-120 nm in diameter) in the mitochondria of chondrocytes and preliminary electron probe analysis of these has indicated a Ca/P mass ratio of approximately 1.14. In the longitudinal septa, about 2 micrometer away from the chondrocytes, matrix-vesicle-like particles could be seen with crystal needles inside them. Micro-analysis of two of these gave a Ca/P mass ratio of 1.73 and 2.68. Cryo-ultramicrotomy appears to confirm a number of conclusions derived from conventional ultrastructural study of growth cartilage and suggests for the first time how amorphous calcium phosphate and crystalline apatite can be shown to exist in different organelles in the same cryo-section of the tissue.

Animals↗
PubMed1976

Comparison of methods for separating proteins using bisalbuminemia as a model.

Sera from bisalbuminemic chicken-turkey hybrids contain two albumins in equal amounts. These are observed as inherited electrophoretic variants and originate from the respective chicken and turkey parents. Sera from the hybrid birds served as a model system by which fractionating and indentification procedures for evaluating serum albumin variants were compared. The two albumins in the hybrid were isolated with preparative polyacrylamide gel electrophoresis (PAGE) and starch block preparative electrophoresis. Isoelectric focusing of the hybrid albumins resulted in the isolation of the turkey albumin. Interference of ampholines prevented the complete isolation of the chicken albumin. The two albumins in the hybrid have identical molecular weights and cannot be identified by sedimentation coefficient, gel filtration behavior, or sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE). Because of the close relatedness the chicken and turkey albumins in the hybrid cross reacted with rabbit anti-hybrid serum as well as with rabbit anti-chicken anti-turkey sera.

Animals↗
PubMed1976

A new arm rest.

Explore the source record for details and available documents.

Anesthesiology↗
PubMed1975

Neoplasms in persons treated with x-rays in infancy: fourth survey in 20 years.

The incidence of neoplastic disease was determined by a mail survey of 2,872 young adults given X-ray treatments in infancy and of their 5,005 nonirradiated siblings. Newly diagnosed benign and malignant neoplasms appeared more frequently in the irradiated subjects than in their siblings or the age- and sex-matched general population of upstate New York. Only thyroid neoplasms occurred in sufficient numbers to permit statistical analysis for the effects on incidence of sex, age, and dose, and of being in a high-risk group (sub-group C). Thyroid cancers developed earlier in life than did benign neoplasms, especially in boys; benign goiters occurred after smaller doses, predominantly in females. Females had a greater risk of developing thyroid cancer than males--2,3 times for females of all ages and 5 times for young adults. Except for young adult females, there was no definite age effect. The risk of cancer (but not of benign goiter) was proportional to the thyroid dose, with a linear risk coefficient of 2.5/year/million people exposed to 1 rad for the entire irradiated population and 4.0 for subgroup C. The high risk of thyroid cancer in subgroup C may be the result of the high percentage of Jews, who had a 3.4-fold greater risk than non-Jews. Young adult Jewish females had a 17-fold increased risk. An incidental observation was an apparent increased incidence of asthma and rare diseases with abnormal immunologic features in the irradiated population.

Adolescent↗