Search PubMed⌕ Search

Biomedical subjects

M E Turner

Publications and source records attributed to M E Turner.

At least 19 recordsLinked to original sources
PubMed1992

Genetic divergence between the Wistar-Kyoto rat and the spontaneously hypertensive rat.

A method of restriction fragment length polymorphism (RFLP) analysis was used to estimate the amount of genetic divergence between the spontaneously hypertensive rat (SHR) strain and the Wistar-Kyoto (WKY) strain. DNA from each strain was digested with eight restriction endonucleases and hybridized with six single copy gene sequences. The number of hybridization bands in each digestion was used to estimate the total number of bases analyzed and RFLPs were scored as single mutations. Divergence was then estimated by dividing the number of mutations by the number of bases analyzed. In a total of 808 bases analyzed in WKY rats, a minimum of 13 mutations were scored in SHR, which yields a nucleotide divergence of 1 change per 62 bp. This is an extremely high amount of divergence given the known origin of these two strains and is comparable to the maximum divergence possible between unrelated humans.

Animals↗
PubMed1991

Use of low-dose subcutaneous recombinant human erythropoietin in end-stage renal disease: experience with children receiving continuous cycling peritoneal dialysis.

The use of recombinant human erythropoietin (rhEPO) for the treatment of renal anemia is well accepted. However, the lowest effective dose for subcutaneous (SC) administration has not been determined. This study documents that a dose of 50 U/kg administered three times a week was effective in 10 children (age range, 13 days to 18.6 years) receiving continuous cycling peritoneal dialysis (CCPD) for a period ranging from 0.25 to 23.5 months. Their hematocrit (hct) increased at an average rate of 0.26% points per day from a baseline of 19.8% +/- 3.1% to a value of at least 30% after a mean of 7.4 +/- 2.5 weeks of treatment. When compared with other studies, this response was more rapid than what has been observed with the same dose administered intravenously (IV). This response was similar to that seen with larger IV doses. Hypertension and functional iron deficiency were the most common complications. Two patients with previously controlled hypertension developed elevation in blood pressure that was easily controlled by oral antihypertensives. Six patients required IV iron dextran to reestablish treatment response. A SC rhEPO dose less than 50 U/kg three times a week may be effective in children and should be investigated.

Adolescent↗
PubMed1991

Separate sex-influenced and genetic components in spontaneously hypertensive rat hypertension.

Previous results from our laboratory indicated two major genetic components of spontaneously hypertensive rat (SHR) hypertension, an autosomal component and a Y chromosome component. Two new substrains, SHR/a and SHR/y, were developed using a series of backcrosses to isolate each of these components. The SHR/a substrain has the autosomal loci and X chromosome from the SHR strain and the Y chromosome from the Wistar-Kyoto (WKY) rat strain. The SHR/y substrain has only the Y chromosome from the SHR and autosomal loci and X chromosome from the WKY strain. Throughout these breeding programs parents were chosen at random without selection for blood pressure. Males of both substrains maintained blood pressures over 180 mm Hg. Comparisons of blood pressure in these new substrains with the original parental strains can be used to determine the relative proportions of each genetic component in hypertension. The Y chromosome component contributes 34 mm Hg, which is the difference between SHR/y male and WKY male blood pressure. The total autosomal component contributes 46 mm Hg, which is the difference between SHR/a male and WKY male blood pressure. The autosomal component is a sex-influenced trait; males in the SHR/a strain have significantly higher pressures than SHR/a females. Of the 46 mm Hg estimated for the autosomal component, 41 mm Hg is the result of these loci interacting with male phenotypic sex. This sex-influenced component is separate and distinct from the Y chromosome component.

Animals↗
PubMed1991

Security measures for AIDS and HIV.

This study describes the measures being taken by AIDS surveillance offices across the country to ensure the security of information regarding patients with AIDS and HIV infection. Security measures were evaluated according to the cumulative number of AIDS cases reported, whether partner notification services were provided, and whether HIV seropositive reporting by name was also required. This study showed that public health departments have taken extra steps to ensure the security of AIDS and HIV data.

Acquired Immunodeficiency Syndrome↗
PubMed1990

Balance performance, force production, and activity levels in noninstitutionalized men 60 to 90 years of age.

The purpose of this study was to collect and analyze balance and muscle performance data obtained from 54 men aged 60 to 90 years. Balance was tested using the sharpened Romberg test (SR) and the one-legged stance test (OLST) on each foot with eyes open and eyes closed. A strain-gauge-based quantitative muscle tester (QMT) was used to measure force production. All torque values were normalized as a percentage of body weight. A self-report of activity level also was recorded. The results indicated that OLST scores and normalized torques of the hip flexors, extensors, and abductors had a positive correlation and that SR scores and normalized torques of the hip extensors and right hip abductors had a positive correlation. Subjects who considered themselves to be very active had a significantly higher SR eyes-closed balance time as compared with those who rated themselves as less active. Subjects who considered themselves to be very active also had significantly higher normalized torque values for most muscle groups tested. Negative relationships were shown between age and balance time and between age and force production.

Aged↗
PubMed1990

Hypertension in the spontaneously hypertensive rat is linked to the Y chromosome.

The objective of our study was to determine the genetic influence on blood pressure in spontaneously hypertensive rats (SHR), and normotensive Wistar-Kyoto (WKY) rats using genetic crosses. Blood pressure was measured by tail sphygmomanometry from 8 to 20 weeks of age. Blood pressure was significantly higher from 12 to 20 weeks in the male offspring derived from WKY mothers x SHR fathers as compared with male offspring derived from SHR mothers X WKY fathers (180 +/- 4 versus 160 +/- 5 mm Hg, p less than 0.01). There was no significant difference between the blood pressure of the F1 females, further supporting Y chromosome linkage and not parental imprinting. The blood pressure data from F2 males derived from reciprocal crosses of parental strains were consistent with the presence of a Y-linked locus, but not with an X-linked locus controlling blood pressure. The data strongly suggest that hypertension in the SHR has two primary components of equal magnitude, one consisting of a small number of autosomal loci with a second Y-linked component.

Animals↗
PubMed1979

Survival and probability of cure without and with operation in complete atrioventricular canal.

Actuarial analysis based on postmortem examination of patients who had been treated nonsurgically for complete atrioventricular (A-V) canal defect shows that only 54% survive to 6 months of age, 35% to 12 months, 15% to 24 months, and 4% to 5 years of age. Our surgical experience since 1975 in 39 patients confirms the idea that primary repair is feasible in small infants. The highest risk of hospital death is when the operation is done in the early months of life; it falls to 17% by age 12 months. Between 1967 and October, 1976, the five-year survival rate among patients leaving the hospital alive after repair was 91%. The age-specific probability of "surgical cure" of patients operated upon for complete A-V canal (alive five years later with mean pulmonary artery pressure less than 25 mm Hg) is maximal at 73% when the operation is done at about 14 months of age. Urgent earlier repair is frequently necessitated by the life history of the disease.

Age Factors↗
PubMed1979

Practical application of generic growth theory and the significance of the growth curve parameters.

The generic growth curve is developed by plausibility arguments based on simple growth models. Parameters of the generic curve include the maximum size, maximum specific growth rate, and a dimensionless velocity constant which can be related to metabolic efficiency in the case of nutrient-limited growth. Parameter estimates are obtained from estimates of the size and time at the point of inflection, the size and time at any other arbitrarily selected point, and the maximum size. Parameter estimates thus obtained and used as initial estimates in nonlinear least squares analysis often give rapid convergence to a minimum error mean square. [For the growth of Escherichia coli K-12 in liquid medium, the generic curve could be simplified to a form containing only three parameters: the maximum specific growth rate, the maximum size, and the time required to reach maximum size. When the bacteria were inhibited by the addition of increasing amounts of the lactoperoxidase antimicrobial factor, there was no significant change in viable counts or maximum specific growth rate, but the time required to reach maximum growth increased linearly with increasing amounts of added antimicrobial factor.] Analysis of growth in terms of the generic growth curve can be a powerful technique for finding relationships which may not be apparent from qualitative consideration of the data.

Biometry↗
PubMed1978

Life expectancy without surgery in tetralogy of Fallot.

All published autopsy cases of patients with tetralogy of Fallot who died without surgical treatment were studied to determine the life expectancy of such persons. In addition, the data from a study of persons with tetralogy alive in Denmark in 1949 were reanalyzed. The survival data from these two sources were remarkably similar, indicating that 66 percent of persons with tetralogy of Fallot not treated surgically live to age 1 year, 49 percent to age 3 years and 24 percent to age 10 years; thereafter, the hazard function (or instantaneous risk of death) remains constant. The chance of survival is significantly less when pulmonary atresia, rather than stenosis, is present.

Adolescent↗
PubMed1978

Allometry and multivariate growth.

Multivariate allometry, and conservative and nonconservative growth models are generalized by a set of global differential equations, preserving the linear trajectory property. Linear least squares methods are exposited for estimation of parameters, comparing special cases and drawing qualitative conclusions. Three classical sets of data are analyzed in detail, illustrating the usefulness and simplicity of the method.

Animals↗
PubMed1977

The performance of the Braunwald-Cutter aortic prosthetic valve.

Four hundred seventy-five patients underwent aortic valve replacement with the Braunwald-Cutter ball-valve prosthesis at two institutions. The early (30-day) hospital mortality was 4.7% for those with isolated aortic valve replacement and 6.9% for the entire group. For the former, 5-year actuarial survival of the hospital survivors was 72 +/- 5.7%; for the latter group it was 71 +/- 4.4%. Eleven patients (5 since the date of follow-up inquiry) have suffered poppet escape, 9 of whom died. The actuarial incidence of known poppet escape is 4 +/- 2.6% at 47 months; when the 5 patients suffering poppet escape since the date of follow-up inquiry are included, with certain assumptions, the incidence is 3.7 +/- 1.14%. The projected probability of poppet escape using all 11 patients is 12.2% at 5 years; the 70% confidence bands of projected probability of poppet escape separate from those of the risk of re-replacement at 61 months. This and other analyses indicate that in general, patients with the Braunwald-Cutter aortic prosthesis should have it replaced 4 1/2 to 5 years after its insertion.

Alabama↗
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

Comparison of left and right ventricular function in acute myocardial infarction.

Pulmonary arterial end-diastolic and mean right atrial pressures were compared in 25 patients with acute myocardial infarction and in one patient with unstable angina. No consistent relationship was observed between these pressures. Simultaneous ventricular function curves relating the stroke work of each ventricle to its respective filling pressure were constructed on 34 occasions, dextran infusion or diuresis being used to alter the filling pressure. The curves from each ventricle were described mathematically by a quadratic (parabolic) function as well as by a straight line function and then compared by canonical correlation analysis. Alterations in the left ventricular function curves occurred with and without depression or right ventricular function curves. These hemodynamic measurements demonstrate that acute myocardial infarction can alter the relationship between left and right ventricular function.

Adult↗