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Biomedical subjects

K A Kirk

Publications and source records attributed to K A Kirk.

At least 73 records · Page 4Linked to original sources
PubMed1984

Attenuated pressure natriuresis in the early phases of two-kidney Goldblatt hypertension.

We studied the effect of changing perfusion pressure on the excretory function of isolated perfused nonclipped kidneys from the two-kidney Goldblatt hypertensive rat ( GHR ). Kidneys were studied from newly hypertensive rats about 8 days after contralateral renal artery clipping [blood pressure (BP) 138 +/- 4.3 mmHg] and before onset of hypertension 3 days following surgery (BP 111 +/- 1.9 mmHg). In addition, nonclipped kidneys from adrenalectomized Goldblatt rats were also examined approximately 9 days following surgery (BP 114 +/- 4.7 mmHg). Kidneys from sham-operated rats served as controls. We noted no differences in GFR in kidneys from newly hypertensive rats and sham controls above a perfusion pressure of 120 mmHg. In response to increasing perfusing pressure, perfusate flow and fractional sodium excretion were significantly lower in newly hypertensive rats than in sham-operated controls. No differences in glomerular filtration rate, perfusate flow, or sodium excretion were noted in kidneys from sham-operated rats or Goldblatt rats 3 days following surgery. After clipping, adrenalectomized (ADX) Goldblatt rats had less of a rise in blood pressure than did rats with intact adrenal glands. No attenuation of natriuresis was noted in the ADX-clipped group in response to increasing perfusion pressure. Isolated perfused kidneys from ADX rats had greater sodium excretion at all levels of pressure than kidneys from rats with intact adrenal glands. Deoxycorticosterone acetate replacement returned sodium excretion to that approaching intact rats. We conclude that nonclipped kidneys of newly hypertensive Goldblatt rats exhibit blunted pressure natriuresis.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenalectomy↗
PubMed1983

Population genetic analyses of insulin dependent diabetes mellitus using HLA allele frequencies.

In order to try to detect heterogeneity within insulin dependent diabetes mellitus (IDDM) and to distinguish a mode of inheritance of IDDM, population genetic analyses were performed using HLA allele frequencies. HLA-A and -B typing performed on 231 IDDM individuals and 268 controls from the southeastern U.S. showed significant increases with IDDM in A2, B8, B15 and B18, and significant decreases in Aw23, B7, B14 and B17. The combination of HLA-B8/B15 showed a greatly increased risk (RR = 25.5). Between the 120 IDDM individuals and 123 controls HLA-DR typed, HLA-DR3 and -DR4 were significantly increased among the IDDM group and DR2 and DR7 were decreased. The risk for DR3/4 was 29.2. It appeared that the B15 association was secondary to the DR4, but the B8/DR3 association showed no difference. Using the method of Curie-Cohen, no significant increases in risk were found for the B8/B15 or DR3/DR4 heterozygotes when compared to the respective homozygotes. Using the method of Thomson and Bodmer, the dominant mode of inheritance was excluded for DR4 only. There was a significant increase in B15 and DR4 in those with onset before age 20. No significant differences were found among the DR phenotypes with respect to season.

Age Factors↗
PubMed1982

Relationship of coronary risk factors to hemodialysis-associated ischemic heart disease.

The records of 320 hemodialysis patients at risk for developing ischemic heart disease (IHD) were examined to determine the influence of the established risk factors of blood pressure, smoking, serum triglycerides, and age on the incidence of IHD and to develop coronary risk profiles for the hemodialysis population. The role of packed red blood cell volume, race, sex, and cause of renal failure on the development of IHD were also examined. None of these risk factors alone, with the exception of age and chronic pyelonephritis, were found to contribute significantly to the incidence of dialysis-acquired IHD. When the joint contribution of these variables was analyzed using Cox regression analysis, race and diastolic hypertension also were discovered to contribute significantly to IHD. However, smoking and serum triglycerides were not found to be significant risk factors. From these data, it is concluded that older patients are a greater risk than younger patients, that white patients are at a greater risk than black patients, that patients with elevated diastolic blood pressure are at an increased risk and that patients with chronic pyelonephritis as the underlying renal disease are at an increased risk.

Adolescent↗
PubMed1981

HLA associations with insulin-dependent diabetes mellitus in a sample of the American Black population.

It has been of considerable interest to determine if the HLA associations with insulin-dependent diabetes mellitus (IDDM) in blacks are the same as in whites in the United States. Seventy-nine black IDDM patients who were under the age of 40 at onset 283 black controls were HLA typed for A, B and C specificities. This is the largest sample of black IDDM patients yet reported. Analysis of HLA antigen frequencies for these samples has revealed an increased frequency of HLA B8 (p less than 0.01), B3 (p less than 0.02) and B15(p less than 0.006), and a decreased frequency of B14 (p less than 0.01). The estimate of relative risks for B8 and B15 was 2.6 and 4.4, respectively. Comparison of a subsample of the black patients (n = 61) and controls (N = 137) revealed increased frequencies of DR3 (p less than 0.0004), DR4 (p less than 0.0002), and DR7 (p less than 0.03) in the IDDM patients. Both HLA DR2 and DR5 were decreased in the diabetic patients (p less than 0.0001 and p less than 0.0002, respectively). All p values were uncorrected. The associations of HLA antigens with IDDM in our black American sample are essentially the same as those found in white IDDM patients. This suggests that the occurrence of IDDM in American blacks may be due to admixture of white genes.

Adolescent↗
PubMed1979

Ischemic heart disease in patients with uremia undergoing maintenance hemodialysis.

The 6-year cumulative incidence of ischemic heart disease (IHD) in 382 dialysis patients (mean age [SEM], 43 +/- 0.7 years) was studied. Of 101 patients with IHD, only 39 developed symptoms following dialysis (cumulative incidence, 20.8%). This group was older than those with IHD, and in 55%, IHD occurred in the first year of dialysis. Analysis by sex and race showed the rate of IHD in men and women to be similar, but the rate in whites was twice that in blacks. In men, the rate was not different from nondialysis men with similar coronary risk factors, whereas in dialysis women, the rate was twice that of nondialysis cohort. The development of IHD did not adversely affect long-term survival in patients without prior evidence of IHD. Death from myocardial infarction occurred in 3 of 320 patients ar risk. Atuopsy data in 33 patients revealed 70% stenosis of coronary arteries in 7, 4 of whom had antecedent disease. Our major conclusions are (a) the incidence of IHD during dialysis was not different from similarly matched nondialysis subjects; (b) the rate of IHD in dialysis women was greater than it was in nondialysis subjects; (c) coronary artery disease only affected long-term survival of patients with preexisting disease; (d) autopsy data did not suggest accelerated atherosclerosis.

Adult↗
PubMed1979

Ischemic heart disease in the hemodialysis population.

We conclude that the incidence of IHD in men undergoing hemodialysis for end-stage renal disease was not greater than that seem in a nondialysis population of men with similar risk factors. In contrast, we found the rate of IHD in women with end-stage renal disease to be accelerated when compared to similar nondialysis subjects. Our data also suggest that during the 6 yrs of hemodialysis, ischemic heart disease did not represent a major mortality risk in patients who had not had symptoms of IHD prior to therapy although it dose pose a significant mortality risk in patients with evidence of established coronary artery disease prior to the onset of dialysis.

Adult↗
PubMed1977

Distribution of 9 trace metals in 17 anatomic sites of dog heart tissue and their classification using pattern recognition.

The concentrations (geometric means of 11 determinations) of 9 trace metals in 17 anatomic regions of dog heart tissue and blood vessels were determined. The relationships recognized within the set of trace metal profiles were comparable to those reported earlier for the cardiovascular systems of pig [J. Mol. Cell Cardiol 6, 383 (1974)] and those of beef [Bioinorg, Chem. (in press)]. These included differences in trace metal concentrations that allowed differentiation of the following tissues from each other: (1) ordinary and specialized myocardium from blood vessels and heart valves, (2) blood vessels from heart valves and (3) arterial from venous tissues.

Animals↗
PubMed1976

Distribution of 8 trace metals in beef heart tissue.

The concentrations of 8 trace metals in 15 discrete anatomic sites of 11 beef hearts have been determined by emission spectrometry. The metals determined were copper, aluminum, barium cesium, tin, strontium, lead, and molybdenum. Anatomic sites samples included aorta, main pulmonary artery, tricuspid valve, mitral valve, right and left coronary arteries, os cordis, right atrium, left atrial appendage, right and left ventricles (free wall), left ventricle-papillary muscle, interventricular septum, crista supraventricularis, and left bundle branch. Statistical analysis of the data incorporated a multivariate analysis of variance and a Duncan analysis. The results showed that many tissues of the beef cardiovascular system have distinctive trace metal compositions.

Aluminum↗
PubMed1976

Use of pattern recognition to classify beef cardiovascular tissues on the basis of their trace metal compositions.

The pattern recognition procedure of discriminant analysis has been used to characterize the trace metal profiles created by the concentrations of 8 trace metals in 15 anatomic sites of beef heart tissue. Metals analyzed were copper, tin, lead, molybdenum, strontium, cesium, barium, and aluminum. Anatomic sites sampled included main pulmonary artery, aorta, mitral and tricuspid valves, left and right coronary arteries, os cordis, right atrium, left atrial appendage, crista supraventricularis, left bundle branch, free wall of the right and left ventricles, interventricular septum, and papillary muscle of the left ventricle. The striking features of the data were: (1) All specimens of the mitral valve, tricuspid valve, and os cordis were ambiguously described by their trace metal profiles; (2) the four blood vessels constituted two groups of two tissues each (aorta, main pulmonary artery; left and right coronary arteries); (3) tissues derived from ordinary and specialized myocardium were quite different from blood vessels, heart valves and os cordis. Using these profiles, 85% of the specimens analyzed were correctly classified by discriminant analysis with respect to their anatomic origin.

Aluminum↗
PubMedDate not supplied

Comparison of various methods for rapid glucose estimation.

We studied the accuracy of three techniques for the rapid estimation of the blood glucose concentration with reagent strips in samples of blood from inpatients with diabetes mellitus. We observed that the visual inspection of Dextrostix gave results that were too inaccurate for this technique to be of practical clinical benefit. In contrast, when performed by registered nurses, both the Dextrostix-Eyetone method and the visual inspection of Chemstrips yielded results that were closely correlated with the measured serum glucose concentrations. With both of the latter techniques, less than 11% of the determinations varied from the actual serum glucose concentration by more than 20%. We conclude that both these techniques are sufficiently accurate to be of potential use in the home monitoring of blood glucose concentrations.

Blood Glucose↗
PubMedDate not supplied

Qualitative issues in developing educational diagnostic instruments and assessment procedures for diabetic patients.

With one exception, psychometric analyses of the quality of instrumentation and educational assessment procedures for diabetic patients have not been reported in the literature. Following an extensive internal review process, a pilot test of 56 diabetic patients found that the newly developed instrument had a high degree of internal consistency for the major indexes, 0.89 and 0.85, respectively. An item analysis found individual questions to be of an acceptable quality. An analysis of interrater reliability of patient assessment procedures produced an r = 0.93. Some support for content and concurrent validity was noted. Using an external review by an expert panel, a revised instrument and protocol was used to conduct a formal field test of 100 diabetic patients. Levels of internal consistency similar to the pilot, 0.87 adn 0.86, were found. An item analysis produced similar positive results. While some support for concurrent validity of the data was found, little support for discriminant validity was evident. The instrument and assessment procedures need to undergo more extensive and rigorous examination of its psychometric characteristics, particularly stability and predictive validity.

Diabetes Mellitus↗