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Biomedical subjects

A McLeod

Publications and source records attributed to A McLeod.

44 records · Page 3Linked to original sources
PubMed1979

Fibrous proteins of normal and abnormal human epidermis.

Keratin proteins of human epidermis have been isolated from normal and abnormal tissues. The normal proteins whether removed from living layers (prekeratin) or from the stratum corneum (keratin) are shown to consist of three chains, molecular weights 65,000 (A), 60,000 (B) and 52,000 (C). When compared with the epidermal proteins isolated from abnormal tissues, differences can be detected in the electrophoretic pattern of the subunits. In general, relative amounts of the individual chains are altered and in specific cases or two of the polypeptides found normally are missing. All the alpha-fibrous proteins extracted are found to be very similar in amino acid composition.

Amino Acids↗
PubMed1978

Precursor keratin protein from human epidermis.

Prekeratin has been isolated from human epidermis using the method of Matoltsy for bovine nose epidermis. Analysis by sedimentation equilibrium indicates that human prekeratin is heterogeneous in solution. The molecular weight range is from about 200 X 10(3) to at least 2 X 10(6). Polyacrylamide gel electrophoresis shows three polypeptide chains of molecular weights 65,000 60,000 and 58,000. A lower than average ratio of polar/apolar amino acid residues suggests that hydrophobic interactions are important for stability.

Amino Acids↗
PubMed1978

The effects of arteriovenous shunts on cardiac function in renal dialysis patients--an echocardiographic evaluation.

To estimate the flow rate in arteriovenous dialysis fistulae and its effect on cardiac function we investigated 7 dialysis patients (1 woman, 6 men, mean age 33 +/- 3 years) echocardiographically before and after 10 minutes occlusion of the arteriovenous shunt. Cardiac index was signigicantly raised (4.31 +/- 0.23 l/min/m2) and fell significantly into the normal range to 3.89 +/- 0.11 l/min/m2 after occlusion of the AV fistula. This reduction was mainly due to a fall in heart rate from 82 +/- 4 beats/min to 76 +/- 5 beats/min. The estimated AV fistula flow rate (0.71 +/- 0.17 l/m) has been similarly reported in invasive hemodynamic studies. Parameters of cardiac contractility were in the lower range of normal with an average of 1.16 +/- 0.10 circ/sec for the mean velocity of fiber shortening (Vcf) and 65 +/- 4% for the ejection fraction. These decreased minimally after fistula occlusion. The single echocardiographic measurements of Vcf and ejection fraction showed good correlation (r=0.97) and revealed evidence that only these patients with poor left ventricular function and septal hypertrophy showed improved cardiac performance after occlusion of the arteriovenous fistula. Thus echocardiography may offer the opportunity to select those patients who need small AV-fistulae for optimal renal and cardiac treatment.

Adult↗
PubMed1975

Clinical applications of free flap transfer in the burn patient.

Free microvascular flap transfer is indicated in situations in which flap coverage is required and no local flap is available. The technique of transfer of a groin flap based on the superficial circumflex iliac vessels was described. The procedure has been applied to two patients with acute electrical burns with extensive soft-tissue loss, three patients with scar contractures, and one with osteoradionecrosis. Satisfactory results were achieved in all patients. The procedure is contraindicated if recipient or donor vessels are abnormal or inadequate, and in the face of fulminating infection, general debility, and obesity. With scrupulous attention to indications and contraindications, the procedure is safe, reliable, and a valuable addition to the surgeon's armamentarium.

Adolescent↗
PubMed1971

X-linked mixed deafness with congenital fixation of the stapedial footplate and perilymphatic gusher.

An X-linked syndrome characterized in males by profound mixed deafness, vestibular abnormalities, congenital fixation of the stapes and perilymphatic otorrhea on attempted stapedectomy has been documented in a large Caucasian kindred. Female heterozygotes have similar but milder audiologic abnormalities. The syndrome of congenital fixation of the stapes with perilymphatic gusher may be a relatively common form of X-linked deafness and is an important clinical entity because affected males may be significantly benefited by sound amplification.

Audiometry↗
PubMedDate not supplied

A comparison of thermocycling devices for automating the polymerase chain reaction.

The polymerase chain reaction (PCR) has become a valuable tool in the fields of cellular and virological research. This paper presents a performance comparison of four devices (three commercial and one prototype) designed to supply the thermic cycle central to the PCR procedure. Results of investigations using a thermocouple revealed that the greatest heating rate and shortest cycle time was attained by the prototype device which used waterbaths as the conducting medium. Dry-block based systems, which heated and cooled a single thermal reservoir, provided generally smaller and more sophisticated machines, but two such devices produced varying results when subjected to experimental analysis. Before purchasing, it is recommended that comparative trials are conducted using differing types of machines, since performance may vary according to individual reactions executed.

Equipment Design↗