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Biomedical subjects

K R Bailey

Publications and source records attributed to K R Bailey.

214 records · Page 12Linked to original sources
PubMed1984

Neomycin and plasma lipoproteins in type II hyperlipoproteinemia.

Neomycin, a nonabsorbable aminoglycoside antibiotic, has been shown to exert a hypocholesterolemic effect in man. In a 9-mo, double-blind, randomized, crossover, placebo-controlled clinical trial, the effect of neomycin, 2 gm/day, on plasma lipoproteins, as well as its safety, was described in 20 subjects with type II hyperlipoproteinemia. A 15% (50 mg%) decline in plasma cholesterol concentration was observed with neomycin. Most of this effect resulted from a 41 mg% (16%) decrease in low-density lipoprotein cholesterol concentration. No significant or consistent effect on the concentration of high-density lipoprotein cholesterol was observed. Monthly audiologic and renal evaluation disclosed no oto- or nephrotoxicity. Neomycin treatment in patients with type II hyperlipoproteinemia is an inexpensive and effective means of lowering the concentration of low-density lipoproteins and is free of significant side effects over a 3-mo period.

Adult↗
PubMed1984

Normalization of plasma lipoprotein concentrations in patients with type II hyperlipoproteinemia by combined use of neomycin and niacin.

The oral administration of neomycin or niacin as single-drug therapy can significantly lower total and low-density lipoprotein cholesterol concentrations in patients with type II hyperlipoproteinemia. However, in the majority of patients treated with one of these drugs as sole therapy plasma lipid and lipoprotein concentrations do not normalize. The effect of combined neomycin (2 g/day) and niacin (3 g/day) treatment on the plasma lipoprotein concentrations was determined in 25 type II hyperlipoproteinemic patients in a double-blind, randomized, placebo-controlled, crossover clinical trial. Treatment with neomycin was well tolerated by all 25 study patients and significantly reduced total and low-density lipoprotein cholesterol concentrations by 23% and 29%, respectively (p less than .05). In contrast to the well-tolerated neomycin regimen, 11 patients (44%) were unable to continue niacin treatment because of adverse side effects. In the 14 patients treated with both neomycin and niacin, niacin further lowered the concentrations of total and low-density lipoprotein cholesterol by 18% and 25%, respectively, and increased high-density lipoprotein cholesterol by 32% (p less than .05) compared with that in the patients receiving neomycin plus niacin placebo. Compared with diet-only therapy, combined treatment with neomycin plus niacin reduced the total plasma cholesterol concentration by 36%, low-density lipoprotein cholesterol by 45%, and the low-density lipoprotein/high-density lipoprotein ratio by 46% and it increased plasma high-density lipoprotein concentrations by 24% (p less than .001). During the study, 80% of all the study patients and 92% of the patients who complied with the combined regimen normalized their total and low-density lipoprotein concentrations.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1984

Race and sex differences in hip fracture incidence.

Incidence rates for hip fracture in the United States were estimated using non-federal hospital discharges from the National Hospital Discharge Survey for the years 1974-1979. Age-specific incidence curves for women and for men showed similar patterns of increase in risk with age, with risks approximately doubling every five years after age 50. Age-specific rates by five-year age groups were compared among the four race-sex groups. No significant differences were observed between Black females, Black males, and White males. In contrast, rates for White females were one and one-half to four times those for Black females after age 40 and were approximately double those for White males after age 50. Analysis based on an independent data source of non-federal hospital discharges in Washington, DC confirmed these relationships. In the Washington study, White women were at twice the risk for hip fracture (controlled for age) compared with Black women and at 2.7 times the risk for hip fracture (controlled for age) compared to White men. No significant differences were observed between Black women and Black men.

Adult↗
PubMed1983

Detection in human serum by radioimmunoassay of histidyl-proline diketopiperazine, a metabolite of thyrotropin-releasing hormone.

Cyclo(His-Pro) is believed to be a metabolite of TRH. A specific antiserum directed against cyclo(His-Pro) was used to detect immunoreactive material in human serum. Gel filtration column chromatography was used to establish that cyclo(His-Pro)-like immunoreactivity was found not only in free form established to be identical to cyclo(His-Pro) by high pressure liquid chromatography analysis on reverse phase and cation exchange columns, but also in a fraction of about 100,000 mol wt. Free cyclo(His-Pro) was released by heating column fractions of 70,000 mol wt that were not immunoreactive before heating. A procedure for estimation of the content of free cyclo(His-Pro) in human serum was developed. Normal levels of cyclo(His-Pro) determined by this procedure were in the range of 11-33 pmol/ml. The level of cyclo(His-Pro) in sera of individuals with hypothyroidism, hyperthyroidism, or alcoholic cirrhosis was in the normal range, while patients with renal failure had approximately 3-fold elevated levels of the peptide. Analysis of human sera drawn at 3-h intervals over a 24-h period suggested a circadian rhythm of cyclo(His-Pro) levels.

Animals↗
PubMedDate not supplied

Inter-study differences: how should they influence the interpretation and analysis of results?

In determining the role inter-study variation should play in an overview analysis, it is important to consider three factors: which question one is trying to answer; the degree of similarity or dissimilarity of design, and the degree to which heterogeneity of outcomes can be explained. Three questions one might be interested in are: whether treatment can be effective in some circumstances; whether treatment is effective on average, and whether treatment was effective on average in the trials at hand. Under the assumption of no qualitative interaction, the answers to these questions coincide. The O-E analysis most directly answers the third question. Other analyses are suggested when the first question is of interest, using the aspirin post-MI studies as an example.

Clinical Trials as Topic↗
PubMedDate not supplied

Restrictive left ventricular diastolic filling identifies patients with heart failure after acute myocardial infarction.

Left ventricular diastolic filling was characterized by transmitral pulsed-wave Doppler velocities in 62 patients with acute myocardial infarction, and diastolic filling variables were correlated with the presence of clinical heart failure. At the time of admission, 47 patients were free of heart failure and 15 patients were in Killip class II to IV. In the latter group of patients with heart failure, peak velocity of late filling wave caused by atrial contraction (A) was lower (0.48 versus 0.59 m/sec, p < 0.05), ratio of peak velocity of early rapid filling wave to peak velocity of late filling wave caused by atrial contraction (E/A) was higher (1.5 versus 1.1, p < 0.01), and deceleration time (136 versus 196 msec, p = 0.0001) was shorter when compared with the patients not in heart failure after acute myocardial infarction. Multivariate analysis showed that the deceleration time was a powerful independent predictor of presence of heart failure after controlling for systolic functional variables. Therefore, diastolic filling variables can complement systolic functional variables in the identification of the patients with postinfarction left ventricular failure.

Adult↗
PubMedDate not supplied

Age-related prevalence of valvular regurgitation in normal subjects: a comprehensive color flow examination of 118 volunteers.

We prospectively assessed the influence of aging on the prevalence of valvular regurgitation by using color flow imaging. One hundred eighteen healthy volunteers (21 to 82 years old) had a two-dimensional Doppler echocardiographic study that included color flow imaging to assess valvular regurgitation and that was semiquantitated by mapping the dimensions of the color flow regurgitant jet in orthogonal views. The subjects were divided into two groups: group 1 consisted of subjects who were younger than 50 years old (n = 61), and group 2 consisted of subjects who were at least 50 years old (n = 57). Mitral regurgitation was detected in 57 (48%) of the 118 subjects: 24 subjects (39%) in group 1 and 33 subjects (58%) in group 2. The severity of mitral regurgitation was trivial to mild. Aortic regurgitation was detected in 13 (11%) of the 118 subjects, all in group 2. The severity was trivial to mild. Tricuspid regurgitation was detected in 77 (65%) of the 118 subjects: 35 (57%) in group 1 and 42 (74%) in group 2. The severity was trivial to mild. Pulmonary regurgitation was detected in 24 (31%) of 78 subjects: nine (22%) in group 1 and 15 (41%) in group 2. The severity was trivial. These findings suggest that valvular regurgitation of a trivial or mild degree is a frequent finding in normal subjects and that it increases with age.

Adult↗
PubMedDate not supplied

Two-dimensional echocardiographic calculation of left ventricular mass as recommended by the American Society of Echocardiography: correlation with autopsy and M-mode echocardiography.

The American Society of Echocardiography (ASE) has recommended diastolic area length and truncated ellipsoid methods for estimating left ventricular (LV) mass by two-dimensional (2D) echocardiography. The major goals of this retrospective study were to (1) assess the correlation between ASE-recommended 2D and M-mode echo-derived measurements of LV mass, (2) compare the two ASE-recommended 2D echocardiography methods, and (3) compare the echo-derived LV mass with anatomic LV mass. The study included 2D echocardiograms obtained within 30 days of death from 34 patients who subsequently underwent autopsy and 2D echocardiograms of 56 normal subjects. The formula used for measurement of M-mode echo-derived LV mass was LV mass = 0.8 (ASE-cube LV mass) + 0.6 gm. For 2D echo-derived LV mass, the ASE-recommended area length and truncated ellipsoid methods in systole and diastole were used, with and without incorporating the papillary muscles into the myocardial shell. LV mass derived by M-mode echocardiography was comparable to that derived by 2D methods, and it is reasonable to use this technique for normally shaped ventricles. When the papillary muscles were included into the myocardial shell, diastolic 2D methods overestimated autopsy LV mass. Both diastolic area length and truncated ellipsoid methods were comparable to autopsy LV mass. When the papillary muscles were excluded, the systolic area length method showed the best agreement with autopsy LV mass.

Aged↗
PubMedDate not supplied

Doppler echocardiographic index for assessment of global right ventricular function.

Echocardiographic assessment of right ventricular function remains difficult and challenging. However, there is considerable clinical need for a simple, reproducible, and reliable parameter of right ventricular function in patients with right-sided heart disease. The purpose of this study was to assess the clinical value of a Doppler-derived index, combining systolic and diastolic intervals of the right cycle, in assessing global right ventricular function in patients with primary pulmonary hypertension. The study population comprised 26 consecutive patients with primary pulmonary hypertension and 37 age-matched normal subjects. The sum of right ventricular isovolumetric contraction time and isovolumetric relaxation time was obtained by subtracting right ventricular ejection time from the interval between cessation and onset of the tricuspid inflow velocities with pulsed-wave Doppler echocardiography. An index of combined right ventricular systolic and diastolic function was obtained by dividing the sum of both isovolumetric intervals by ejection time. The index was compared with available parameters of systolic or diastolic function, clinical symptoms, and survival. Right ventricular isovolumetric contraction time and isovolumetric relaxation time were prolonged significantly in patients with primary pulmonary hypertension (85 +/- 41 msec and 135 +/- 43 msec) compared with normal subjects (38 +/- 7 msec and 49 +/- 9 msec, respectively; p < 0.001). Ejection time was shortened significantly in patients with pulmonary hypertension (241 +/- 43 msec versus normal [322 +/- 21 msec]; p < 0.001). However, the index was the single most powerful variable to discriminate patients with primary pulmonary hypertension from normal subjects (0.93 +/- 0.34 versus 0.28 +/- 0.04; p < 0.001) and was the strongest predictor of clinical status and survival. The index was not significantly affected by heart rate, right ventricular pressure, right ventricular dilation, or tricuspid regurgitation. It is well known that right ventricular systolic and diastolic dysfunction coexist in patients with primary pulmonary hypertension. This article reports the use of an easily obtainable Doppler-derived index that combines elements of systolic and diastolic function. This index appears to be a useful noninvasive means that correlates with symptoms and survival in patients with primary pulmonary hypertension.

Adult↗
PubMedDate not supplied

Prognostic value of treadmill exercise testing: a population-based study in Olmsted County, Minnesota.

BACKGROUND: The prognostic value of treadmill exercise testing (TMET) has been studied in selected populations. The generalizability of these data to different populations and to women is uncertain. METHODS AND RESULTS: A retrospective, population-based cohort study of all persons (1452 men and 741 women) who underwent TMET in years 1987 to 1989 in Olmsted County, Minnesota, was undertaken. Individuals were followed up for all-cause mortality and cardiac events (cardiac deaths, nonfatal myocardial infarction, or congestive heart failure). Sex-specific analyses were performed to determine whether the predictors of outcome and the magnitude of the associations were similar in both sexes. In men, 77 deaths and 106 cardiac events occurred during 8956 person-years of observation; in women, 46 deaths and 54 cardiac events occurred during 4801 person-years of follow-up. Exercise-induced angina, ECG changes, and workload achieved on the TMET were strongly associated with all-cause mortality and cardiac events in both sexes, and the strength of the association was similar. After adjustment, workload was the only TMET variable associated with outcome. A higher workload was associated with a reduction in the risk of cardiac events and of all-cause mortality; the protective effect of exercise capacity was strong and was similar in both sexes. CONCLUSIONS: In this population-based cohort, exercise capacity was the TMET variable that exhibited the strongest association with all-cause mortality and cardiac events. This protective effect of exercise capacity was observed in both sexes.

Aged↗
PubMedDate not supplied

Effect of heparin-binding growth factor-1 on bronchial healing in canine lung allograft transplantation.

Failure of airway healing complicates lung transplantation. Local application of heparin-binding growth factor-1 induces neovascularization in vivo. To determine the effect of direct application of heparin-binding growth factor-1 on bronchial healing, we performed single left lung allotransplantations in 12 dogs, and wrapped the bronchial anastomosis with Gelfoam impregnated with either recombinant heparin-binding growth factor-1 (100 micrograms, n = 6) or saline solution (n = 6) in a blinded fashion. After 21 days, the bronchial anastomosis was studied by gross examination, light and electron microscopy, bromodeoxyuridine uptake, measurement of bronchial breaking strength, and high-speed computerized tomography to assess bronchial cross-sectional area and distensibility. The transplanted lung was examined histologically for concomitant lung rejection. No significant difference was found between the two groups in histologic bronchial healing scores, proliferation index, bronchial breaking strength, cross-sectional area, anastomotic distensibility, or local blood flow as estimated by high-speed computerized tomography scan. In the growth factor group, both increased neovascularization and lung rejection were found at histologic evaluation. We conclude that, although the use of heparin-binding growth factor-1 increased perianastomotic neovascularization, it did not contribute to improved bronchial healing, possibly because of increased lung rejection.

Anastomosis, Surgical↗