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Biomedical subjects

E O'Brien

Publications and source records attributed to E O'Brien.

At least 253 records · Page 14Linked to original sources
PubMed1986

Mitotic inhibitors arrest the growth of Plasmodium falciparum.

We report that the mitotic inhibitor, vinblastine (VLB), is highly toxic to the malarial parasite, Plasmodium falciparum. In cultures in vitro growth is inhibited by 50% at a VLB level of about 28 nM, and totally abolished at a level of 100 nM. By tests on synchronized cultures we have found that the effect of VLB takes place at the trophozoite stage. Colcemid also inhibits schizogony with somewhat different kinetics. By mutagenesis with nitrosoguanidine followed by VLB selection we have isolated a VLB-resistant mutant which exhibits cross-resistance to vincristine. These data suggest a critical role of microtubules in the asexual schizogonic cycle of P. falciparum.

Animals↗
PubMed1986

The effect of age on blood pressure and heart rate variability in hypertension.

There is confusion in the literature as to the effect of ageing on blood pressure variability. The lack of consistency in reports probably reflects differences in blood pressure measurement techniques and in the choice of statistics used to describe variability. We studied 16 hypertensives (clinical blood pressure greater than 140/90 mmHg on 3 occasions) over 60 (67 +/- 5.5 years) and 16 under 60 years of age (44 +/- 8.9 years) using the Remler M 2000 ambulatory system to measure blood pressure and heart rate every 30 min during the awake hours of the day. Mean +/- s.e.m. blood pressure and heart rate for the elderly was 168 +/- 2.5/95 +/- 1.0 mmHg and 72 +/- 1.5 beats/min, corresponding values for the young being 162 +/- 5.3/103 +/- 2.1 and 78 +/- 2.5. Four statistics of variability were used: standard deviation, coefficient of variation, range and mean hourly change. Differences between old and young were found only for the range of systolic and diastolic blood pressure which was lower in the elderly (52 +/- 3.9/32 +/- 2.4 versus 67 +/- 5.2/46 +/- 4.8 mmHg, both P less than 0.05) and mean hourly change of heart rate (P less than 0.05). The standard deviation of heart rate was negatively correlated with age (r = -0.37; P less than 0.05). Only the systolic and diastolic blood pressure ranges were found to differ with age; the more rigorous tests of variability, standard deviation and coefficient of variation, were not changed. These data show that in hypertensives of different age but with roughly comparable blood pressure levels, variability of blood pressure is not consistently related to age.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Report on variation in rates of utilization of surgical services in the Commonwealth of Massachusetts.

This article presents an analysis of over 140,000 selected surgical procedures performed in Massachusetts in 1980, giving the per capita rates of 14 common procedures and of four less frequently performed procedures. The analysis defines 172 geographic areas for the commonly performed procedures and 45 for the less frequently performed procedures. Per capita surgical rates among the defined areas are significantly different from both a statistical and a clinical point of view. Twofold and threefold variations occur frequently across geographic areas. In certain areas, some surgical services appear to be provided at rates substantially different from the statewide rate. We discuss the importance of these data for physicians as well as the implications for the distribution and quality of clinical care and for containment of medical care costs.

Costs and Cost Analysis↗
PubMed1985

Accuracy and reliability of the Del Mar Avionics pressurometer III.

We assessed the accuracy and reliability of the Avionics pressurometer, a fully automated ambulatory blood pressure recorder. Accuracy was assessed in 96 patients against the Hawksley random-zero sphygmomanometer. Two recordings were made with each device in a random sequence. No mean difference was found between methods. However, there was a marked variation in the difference between Avionics and Hawksley recordings. This was not due to variability in blood pressure alone since the agreement between Avionics and pressurometer systolic recordings (r = 0.88) was less than the agreement between sequential systolic blood pressure measurements with the Hawksley (r = 0.976, P < 0.001). In addition, a small degree of inter-device variability was demonstrated between three Avionics recorders, one device giving higher readings. Reliability was assessed in 30 patients during normal daily activities and compared with the Remler M2000. The rate of markedly artefactual recordings was higher with the Avionics. Thus, variability in Avionics recordings makes this device unreliable.

Blood Pressure Monitors↗
PubMed1985

Adverse effects of human leukocyte antigen-DR sharing on fertility: a cohort study in a human isolate.

To elucidate further the reproductive effects of human leukocyte antigen (HLA) sharing among spouses, we have been investigating prospectively the relationship between HLA-A, -B, and -DR sharing and reproductive outcome in the Hutterites, a religious isolate that proscribes contraception. For the first time the reproductive effects of HLA-DR sharing in a fertile population is reported in this article. Median intervals from marriage to first through fifth births were longer among couples who shared more than one HLA-A, -B, or -DR antigen. Longer intervals were associated with increased spontaneous abortion rates among couples who shared HLA-DR antigens (27%), compared with couples who shared only HLA-A or -B antigens (9%) and couples who shared no antigens (12%). Median completed family sizes were 5.0, 8.5, and 8.0 among the groups, respectively. However, some couples who shared HLA-DR antigens experienced no spontaneous abortions, despite ten or more pregnancies. Therefore, although HLA-DR compatibility, per se, is not deleterious, our data suggest a potentially important role for undefined HLA-linked genes in normal pregnancy.

Abortion, Spontaneous↗
PubMed1985

Compliance in elderly hypertensives.

Hypertension is common in the elderly. While it is possible to reduce blood pressure in this age group, the value of such treatment in terms of reduced mortality and morbidity is unknown. The effects of a prescribed regimen depends inter alia on compliance. Therefore, this variable must be taken into account in assessing drug treatment in the elderly hypertensive. In general, the elderly comply well with drug treatment but there are a number of well defined problems in this age group.

Adult↗
PubMed1985

The role of home and ambulatory blood pressure recording in the management of hypertension.

A review of the literature shows that doctor-recorded measurement (DRM) of blood pressure is higher than patient-recorded measurement (PRM) by either home-recording or ambulatory measurement. The role of home-recording and ambulatory measurement as a means of supplementing doctor-recorded measurement is discussed. The results of two studies comparing home-recording with clinic and ambulatory blood pressure showed that home-recording of blood pressure did not lower blood pressure.

Blood Pressure Determination↗
PubMed1984

Platelet cryopreservation. 1. In vitro aggregation studies.

Platelets were harvested by a Hemonetics Model-30 discontinuous cell separator from 20 normal volunteers and were cryopreserved in the presence of 5% DMSO at a controlled rate of freezing of -1 degrees C/min and stored in liquid nitrogen for up to 3 months. A significant loss of platelets occurred at the platelet concentration step through adhesion of platelets to the bag walls. A small reduction in aggregation associated with this was also seen and may reflect some damage to the platelets during the pheresis procedure. A small, but significant loss of platelet aggregation was seen with all agents following cryopreservation. Mean percentage aggregation post-thaw for all the agents was 75.4% (range 74-78%) and platelet recovery was approximately 90%. No significant changes in aggregation or recovery were seen over the 3 months' storage period. The cryoprotectant DMSO was shown to have no deleterious effect on platelet function in vitro.

Blood Platelets↗
PubMed1984

Attitude change and a prison health care experience.

Nursing in a prison setting has recently emerged as a field of concern. One of the issues in staff working with prisoners is attitudes and attitude change. Since the most favorable site for attitude formation and/or change is a student's educational experience, the present study was undertaken to explore if nursing students who have a clinical experience with prisoners will demonstrate a change toward more favorable attitudes toward prisoners. The research design was a pre-test, post-test control group design. The instrument was a Likert scale, adapted from previously developed scales dealing with attitudes toward prisoners, the mentally ill, and drug addicts. An important control was contained in the instrument, in that not only were there statements dealing with prisoners, but also dealing with the mentally ill and addicts, with whom none of the students would have student clinical experience. The results revealed that there was no significant difference in attitudes toward prisoners, drug addicts, and the mentally ill on the pre-test for either experimental or control group. However, on the post-test, there was a significantly lower (more positive) score on the scale for prisoners for the experimental group, who had a prison clinical experience. This finding suggests that attitudes can be favorably altered by a relevant student clinical experience.

Attitude↗
PubMed1983

Antihypertensive and renal haemodynamic effects of atenolol and nadolol in elderly hypertensive patients.

As little is known of the antihypertensive efficacy or renal haemodynamic effects of beta-adrenoceptor blocking drugs in the elderly we studied two such drugs, atenolol and nadolol, in elderly hypertensive patients. Ten patients took part in a placebo-controlled double-blind study of atenolol and 10 received nadolol in a single-blind placebo-controlled study. Treatment phases lasted 12 weeks for atenolol or 10 weeks for nadolol. Blood pressure, effective renal blood flow and glomerular filtration rate data obtained at the end of each treatment phase were analysed. Atenolol lowered mean arterial pressure (mean +/- s.e. mean) from 129.9 +/- 1.5 to 108.2 +/- 2.3 mm Hg (P less than 0.01) while it increased mean effective renal blood flow 512.5 +/- 86.6 to 646.0 +/- 116.1 ml min-1 1.73 m-2 (P less than 0.05). Nadolol reduced mean arterial pressure from 133.2 +/- 2.0 to 113.5 +/- 3 mm Hg (P less than 0.001) but reduced mean effective renal blood flow from 558.8 +/- 32.2 to 446.0 +/- 26.9 ml min-1 1.73 m-2 (P less than 0.05). Glomerular filtration did not alter significantly with either drug. We conclude that beta-adrenoceptor blocking drugs are effective antihypertensive agents in the elderly but have disparate effects on effective renal blood flow perhaps because of differences in cardioselectivity. These data suggest that comparative studies with thiazide diuretics and beta-adrenoceptor blocking drugs are warranted in elderly hypertensives.

Adrenergic beta-Antagonists↗