Biomedical subjects
Publications and source records attributed to T Harris.
Psychiatric technicians are becoming increasingly important in the inpatient psychiatric setting, yet few educational programs properly prepare students for this demanding role. By structuring interviews around practical, real life dilemmas faced by technicians, the interviewer can establish which applicants are best suited for the job, thus helping to improve satisfaction and retention.
Two transfused Caucasian patients presented with possible delayed transfusion reactions. Both patients demonstrated an anti-Fya (Fy1) plus anti-Fyb (Fy2) pattern of reactivity in their sera. The patients' red blood cells (RBCs) were Fy:1,-2,3. Both had positive direct antiglobulin tests (DAT) with anti-IgG and -C3d. The serum antibodies reacted with the patients' RBCs drawn when the DATs were negative Both patients' serum samples showed reactivity with Fy:1,-2 (1+), Fy:-1,2 (3+), Fy:1,2 (3+) RBCs at the antiglobulin phase (AGT) but were nonreactive with Fy: -1, -2 RBCs. The antibodies in both cases were nonreactive with papain- or ficin-treated RBCs and reacted with Rhnull RBCs, which ruled out anti-Fy3 and anti-Fy 5 respectively. These cases suggest mimicking autoantibody specificities in the Duffy system one case may indicate that the degree of reactivity is dependent on the Duffy phenotype of the RBCs tested( Fy:-1,2 > Fy:1,2 > Fy: 1,-2). An unusual characteristic seen in both of these cases was hemolysis in the EDTA cell samples but none In the clotted samples.
We have explored the structure and subunit composition of the vacuolar ATPase of Neurospora crassa by investigating the effects of nitrate. Inhibition of enzyme activity by nitrate was correlated with dissociation of a complex of peripheral polypeptides from the integral membrane part of the enzyme. Surprisingly, this nitrate-induced release of subunits occurred only when nucleotides such as ADP, ATP, or ITP were present. ATPase inhibitors that have been proposed to act at the active site prevented release of subunits. Six polypeptides, 67, 57, 51, 48, 30, and 16 kDa, were coordinately released from the vacuolar membrane. When analyzed by size exclusion chromatography or by centrifugation through glycerol gradients, the six polypeptides behaved as an aggregate of about 440,000 kDa. We also examined vacuolar membranes by electron microscopy, using negative staining. We observed a high density of "ball and stalk" structures on the membranes, similar in size but different in shape from the F0F1-ATPase of mitochondrial membranes. Treatment with nitrate removed the ball and stalk structures from vacuolar membranes but had no visible effect on mitochondrial membranes. We concluded that the overall structure of the vacuolar ATPase is similar to that of F0F1-ATPases; however, the sizes of the component polypeptides and the factors that can cause dissociation are different.
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The National Health and Nutrition Examination Surveys (NHANES) are important in the assessment of nutritional status of the population of the United States. The utility of these surveys for assessment of the nutritional status of older Americans has been limited because prior NHANES have not included persons aged greater than or equal to 75 y. This paper reviews the role of the NHANES for nutritional epidemiology, highlighting the unique opportunity NHANES III offers to expand the nutrition database for older persons. Data are presented on consequences of nonresponse in analytic work and mechanisms that have been devised to approach the potential problem of nonresponse within NHANES III.
Polyagglutinable erythrocytes expressing the rare human blood group phenotype Tn were tested for expression of both Tn (GalNAc alpha 1----O-Ser/Thr) and sialosyl-Tn (NeuAc alpha 2----6GalNAc alpha 1----O-Ser/Thr) antigens by agglutination with a panel of well-characterized monoclonal antibodies specifically directed to Tn and sialosyl-Tn antigens, respectively. Tn erythrocytes from 4 patients were strongly agglutinated by both sialosyl-Tn and Tn-specific monoclonal antibodies, indicating coexpression of sialosyl-Tn and Tn antigens on the cell membrane surface of Tn polyagglutinable erythrocytes. Human polyclonal anti-Tn antisera were found to express weak and variable anti-sialosyl-Tn antibodies in conjunction with the anti-Tn antibodies. The Tn phenotype thus involves not only the classically known Tn antigens but also sialosyl-Tn antigens. However, the human anti-Tn antibodies may be directed mainly toward the Tn antigen (GalNAc alpha 1----O-Ser/Thr).
Bovine culture endothelial cells (BAECs) generate platelet-activating factor (Paf) following activation by bradykinin (Bk 0.1 nM), the ionophore, A23187 (3 microM), and ATP (10 microM), but Paf is not released from the cells. These stimuli also elicit generation of prostacyclin (PGI2). The specific and competitive Paf receptor antagonists, WEB 2086 (0.1-1.0 microM) and CV 6209 (0.01-0.1 microM), inhibited Bk-, A23187- and, to a lesser extent, ATP-induced PGI2 generation but had no effect on basal PGI2 generation. These data suggest a role for intracellular Paf in signal transduction.
A cohort of 3,595 white women aged 40-77 years was followed for an average of 10 years during which 84 new cases of hip fracture were identified. Triceps skinfold thickness and arm muscle area measured at baseline were examined as possible risk factors for hip fracture controlling for physical activity, height, menopausal status, calcium consumption, and smoking. Of these variables only arm muscle area, triceps skinfold thickness, and activity in recreation were independent predictors of hip fracture incidence using the Cox proportional hazards model. After adjustment, the estimated relative risk of hip fracture was approximately two for an increment of each anthropometric indicator (adjusted for the other) equivalent to comparing those at the 25th percentile to those at the 75th percentile (maximum width of 95% confidence intervals, 1.2-2.9). Risk of hip fracture was approximately two-fold for persons who reported little recreational exercise compared to persons who reported much recreational exercise (95% confidence interval, 1.2-3.2). Our findings are the first evidence from a prospective study that anthropometric indicators besides body mass index may have an independent relationship to risk of hip fracture.
Information was obtained on stressful life circumstances, using the Life Events and Difficulties Schedule (LEDS) from 39 patients with early multiple sclerosis and 40 matched nonpatient volunteers. The proportion of multiple sclerosis patients who experienced marked life adversity in the year prior to onset of symptoms was significantly higher than for nonpatients in the year before interview (77% vs. 35%). The excess in marked life stress was most evident in the 6 months before onset. Such stressors might explain the timing of symptom exacerbation for some patients with multiple sclerosis, perhaps by perturbing an already unstable neuroimmunological system.
The National Health and Nutrition Examination Survey (NHANES I) Epidemiologic Follow-up Study, an investigation of a cohort originally examined during the period 1971-1975, provided an opportunity to assess the frequency of antihypertensive drug therapy in the United States during the period 1982-1984. For most age-sex-race subgroups, the frequency of medication use during 1982-1984 was higher than that observed during 1976-1980 based on the NHANES II. In the interval 1982-1984, diuretic agents were the most frequent medications prescribed (47% of drugs prescribed), and beta-blockers were second (17%). At the time of the initial survey in 1971-1975, participants had their blood pressures measured and a history of diagnosis and treatment of hypertension ascertained. Follow-up for vital status was 93% complete by 1984 (average length of follow-up, 9 years). In white men and women aged 50 years and older, the relative risk of death increased steadily, from those with elevated blood pressure (systolic blood pressure greater than or equal to 160 mm Hg or diastolic blood pressure greater than or equal to 95 mm Hg) but no history of hypertension to those treated for hypertension but whose blood pressure was still elevated. Regardless of history or treatment, those with an elevated blood pressure had about a 25-30% excess risk of death. Evidence from these national studies shows a high frequency of antihypertensive drug therapy in 1982-1984 and suggests the importance of adequate blood pressure control for optimal survival.
Based on 1984 data from the Longitudinal Study on Aging, one-third of White persons aged 80 or older living in the community (N = 1,791) were defined as having no difficulty in walking 1/4 of a mile, in lifting 10 pounds, in climbing 10 steps without resting, or in stooping, crouching or kneeling. Physical ability was associated with lower risk of death over two years mean follow-up; Relative odds (RO) = .4 (95 percent confidence interval = .4, .6) and in survivors, lower utilization of hospitals RO = .4 (CI = .3, .7), physicians RO = .6 (CI = .5, .8) and nursing homes RO = .3 (CI = .2, .5) compared with those having difficulty on any of the four functional measures included in the definition of physical ability. Fifty percent of the women and 42 percent of the men physically able at the time of the baseline survey in 1984 remained physically able at follow-up. Continued physical ability in this group was associated with never having had cardiovascular disease RO = 2.1, (CI = 1.2, 3.7), never having had arthritic complaints RO = 1.9 (CI = 1.2, 2.7), a body mass index less than the 75th percentile RO = 1.8 (CI = 1.2, 2.9), younger age (for each decade of age, RO = 2.0 (CI = 1.1, 3.6), and higher level of education (greater than 13 years versus 0-6 years) RO = 2.4 (CI = 1.2, 4.7). These correlates include factors amenable to preventive measures and highlight the need to consider the heterogeneity of the oldest-old in formulating programs aimed at prevention and postponement of disability.
The relationship of weight at age 65 years and subsequent mortality was examined in a population of 1723 nonsmokers who were followed up from one to 23 years (mean, 9.5 years) during the Framingham Heart Study. In sex-specific proportional hazards analyses, risks of mortality were increased for men and women at the high and low extremes of body mass index, even when accounting for potential effects of excess weight on serum cholesterol level, blood glucose level, and systolic blood pressure. For those at the lower extreme of body mass index, the relative risk of death was almost twice as high in the years immediately after age 65 years as in later follow-up, suggesting that the increased early death rate was due to disease that was already present. At the upper extreme, risk of death was twofold over the entire follow-up period for persons with body mass indexes at or above the 70th percentile at both 55 and 65 years of age. We conclude that, even when accounting for cardiovascular risk factors, being overweight is a serious health problem for older people, especially for those with long-standing weight problems.
Risk factors for coronary heart disease were examined in 2,501 individuals in the Framingham Heart Study who survived to the age of 65 without evidence of coronary artery disease. We used a proportional hazards (Cox) analysis that examined risk factors over time and included events through the 16th biennial examination. The independently significant multivariate correlates of the development of coronary heart disease after the age of 65 were sex (incidence rate ratio [RR] for males of 1.7 [95% confidence interval of 1.4,2.0]), left ventricular hypertrophy (RR = 2.4 [1.7,3.5]), systolic blood pressure (RR = 2.2 [1.4,3.3] for systolic blood pressure of 160 mmHg or higher as compared with less than 120 mmHg), casual blood glucose (RR = 2.2 [1.5,3.4] for 175 mg/dL or more as compared with less than 90 mg/dL), Metropolitan relative weight from examination 1 (RR = 1.3 [1.0,1.6] for those 130% or more of ideal weight compared with those less than 110% of ideal), and total serum cholesterol (RR = 1.8 [1.3,2.5] for cholesterol in the 90th percentile or higher compared with less than 200 mg/dL). Controlling for all these risk factors, those smoking 20 cigarettes a day or more were at slightly increased risk of coronary heart disease (RR = 1.2 [.9,1.6]) compared with nonsmokers. These analyses suggest that older persons share the same risk factors for coronary artery disease that are significant in younger populations.
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This paper addresses the critique which maintains that loss of parent in a sample of female adults plays no role in determining current depression over and above that of low social class position with which such loss is associated. It examines a series of variables which combine to determine current social class position and which seem to stem from lack of adequate replacement care following loss of mother. The experience of a premarital pregnancy and the way in which women cope with it emerge as critical in this process. The relationship of low social class to the onset of depression is discussed in the light of better-known vulnerability factors such as low confiding in, and undependability of, marital partner, employment outside the home and number of children. It is concluded that a current low social class position, far from explaining away the association between loss of mother and current depression, may itself be brought about by a chain of circumstances stemming from the loss. Once again, the quality of replacement care is shown to play a critical role.
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We have compared the pattern of neural catecholamine fluorescence with that of immunoreactivity for the catecholamine-synthesizing enzymes tyrosine hydroxylase (TH) and DOPA decarboxylase (DDC) in dog atrium, which is innervated by noradrenergic nerves, and in dog kidney, which is thought to be supplied by dopaminergic nerves as well. In both tissues the distribution of nerves containing catecholamine fluorescence was similar to that of nerves exhibiting TH-like immunoreactivity. By contrast, DDC-like immunoreactivity was present in some (but not all) of the nerves associated with the intrarenal blood vessels, but was not detectable in any atrial nerves. High DDC activity provides further confirmation of the existence of sympathetic dopaminergic neurons supplying the kidney.