Biomedical subjects

R C Fraser

Publications and source records attributed to R C Fraser.

70 records · Page 4Linked to original sources

PubMed1978

Sex hormones and the immune response. II. Perturbation of antibody production by estradiol 17beta.

The administration of 75 microgram/kg of estradiol 17beta at successively later stages in the immune response of female guinea pigs to penicilloyl-coupled cavian globulins showed that this steroid reduces the rate of attainment of the maximum titer, the magnitude of the titer achieved, and the rate of titer decay. Control titers maximized at the third experimental week and diminished to one third the peak value by the 6th week. When steroid treatment was begun coincidentally with inoculation (week 0), the peak titer was delayed by 3 weeks, and by 2 weeks when hormone priming was begun at week 1 or 2. The highest antibody titers achieved in the presence of estrogen were 25-30% lower than those of sesame oil controls. The greatest immunosuppressive effect was observed when estradiol was given at the peak of the immune response, the titer dropping by 50% and remaining at that level for the next 4 weeks in spite of continued antigen inoculation and steroid treatment. Titer decay after the end of the inoculation course was prevented by estradiol but not by progesterone, CHP, or these same oil vehicle.

Animals↗

PubMed1978

Sex hormones and the immune response. I. Host factors in the production of penicillin-specific antibodies in the female guinea pig.

Female guinea pigs between 500 and 650 g produced the highest precipitation titers to penicilloyl-coupled guinea pig gamma-globulin of an array of animals ranging in weight from 350 to 850 g. When one or two depot injections in complete Freund's adjuvant were succeeded by saline boosters, the response maximized within 1 week after the first booster (in phase with the maximum output of IgM); subsequent boosters rapidly reduced the titer. The observed response was directed primarily at the hapten, as no reaction was evident to heterologous carrier (KLH) until the anti-hapten titer had declined. The daily administration of estradiol for 23 days after the last antigen inoculation prevented the decay of titer, whereas the titer of the controls or progesterone-treated animals dropped by 40--50% during that interval.

Animals↗

PubMed1978

The reliability and validity of the age-sex register as a population denominator in general practice.

I report evidence which raises doubts about the reliability and validity of age-sex registers as true population denominators in general practice in the UK. These have potentially disturbing implications for the interpretation of data based on the presumed precision of age-sex registers. I am undertaking a prospective study to identify and quantify sources of inaccuracy to try to establish a method of estimating the true population at risk and its true age-sex characteristics. This would greatly enhance the utility of the age-sex register as the most valuable tool in general-practice research.

Family Practice↗

PubMed1977

Cortisone-induced cleft palate in the mouse. A search for the genetic control of the embryonic response trait.

The cause of the difference in the mean tolerance (ED50) to cortisone-induced cleft palate between the embryos of the A/J and C57BL/6J strains appears to be due to a small number of genes. A single major gene effect and a polygenic model, in the sense of many equal and additive genes, have been ruled out. The embryonic tolerance of C57BL/6J is greater than and dominant to that of A/J; two or three loci, possibly with independent effects, appear to explain the variability. A component of the variation in embryonic response may be associated with or linked to the major histocompatibility locus (H-2). No evidence was found to support the hypothesis of X-chromosome linked susceptibility to cortisone-induced cleft palate.

Abnormalities, Drug-Induced↗

PubMed1976

Is the cervix normal? How do you arrive at that conclusion?

It is the responsibility of practicing physicians to determine, at the earliest possible time, the presence or absence of neoplastic disease of the cervix. Modes of treatment for cervical cancer will vary according to geographic location, the expertise of those providing treatment, and current clinical trials.

Biopsy↗

PubMed1975

Variations in right and left coronary blood flow in man with and without occlusive coronary disease.

The relation of angiographically recognized coronary occlusion to regional myocardial blood flow has not been studied adequately in spite of its clinical significance. This is particularly important, as revascularization procedures, based on angiographic studies, are being performed with increasing frequency. To compare the severity of reduction in flow to the severity of coronary occlusion, regional myocardial blood flow (85-Kr washout) was measured in 34 patients. Selective coronary anteriograms were obtained using the Sones technique, and occlusions were graded as a percentage of luminal diameter. Of 26 right coronary arteries for which satisfactory arteriograms and coronary blood flow measurements were obtained, 16 were normal and 10 had significant stenosis (greater than 50%). Dominant right coronary arteries appeared to have high flows (67 plus or minus 6 ml min-minus1 per 100 g muscle) and a greater incidence of occlusion (10 of 20) than nondominant arteries, which had less flow (41 plus or minus 2 ml min-minus1 per 100 g muscle) and a lower incidence of occlusion (1 of 8). Coronary blood flow in 16 normal left coronary arteries was 84 plus or minus 5 ml min-minus1 per 100 g muscle and in 15 with 50 per cent or greater occlusion, 68 plus or minus 3 ml min-minus1 per 100 g muscle. Though coronary blood flow appeared reduced when lesions of both the right and left coronary arteries were present, a critical reduction was seen only when occlusion was greater than 90 per cent.

Adult↗

PubMed1975

First-degree atrioventricular block: a cause of false malfunction of a mitral disc-valve prosthesis. Case report.

Malfunction of a prosthetic mitral disc valve was clinically suspected on the basis of absent valve closing sound and an early opening click in a patient with first-degree atrioventricular (A-V) block. Premature closure and opening of the prosthetic valve was demonstrated by echocardiography. All abnormal auscultatory, phonocardiographic, and echocardiographic findings disappeared promptly upon spontaneous restoration of normal A-V conduction. The possible hemodynamic mechanism is discussed, and attention is drawn to this conduction abnormality as a cause of erroneous diagnosis of prosthetic mitral valve malfunction.

Adult↗

PubMed1975