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Biomedical subjects

J Low

Publications and source records attributed to J Low.

At least 55 records · Page 3Linked to original sources
PubMed1990

Increased plasma beta-thromboglobulin in patients with coronary artery vein graft occlusion: response to low dose aspirin.

The therapeutic effect of aspirin on vein graft patency was studied in patients undergoing coronary artery bypass graft surgery. The study design enabled the prospective evaluation of the relation of platelet activation, as measured by plasma beta-thromboglobulin concentration, to subsequent coronary vein graft occlusion. Serial beta-thromboglobulin levels were measured in 105 patients randomized to receive aspirin (324 mg/day) or placebo beginning within 1 h after surgery. Graft patency was assessed angiographically at 1 week and 1 year after surgery. Of 49 patients receiving placebo, 17 (34.7%) had one or more graft occlusions, 6 early, 10 late and 1 with both early and late occlusion. Of 56 patients receiving aspirin, 7 (12.5%) had one or more occlusions, 3 early and 4 late (p less than 0.01). Preoperatively, the beta-thromboglobulin level in surgical patients (29 +/- 13.5 ng/ml) was significantly higher than that of 51 control subjects (22.6 +/- 11.1 ng/ml) (p less than 0.004). Plasma beta-thromboglobulin levels remained comparatively constant at 3 and 12 months after surgery in the 43 patients who had both samples available (p less than 0.001, r = 0.65). The reduction in beta-thromboglobulin concentration from the preoperative level to 12 months postoperatively was greater in the aspirin-treated group (p less than 0.001). Multivariate logistic regression analysis demonstrated a significant association between preoperative beta-thromboglobulin concentration and graft occlusion (p less than 0.02), and aspirin treatment was effective in preventing occlusion when adjusted for the preoperative beta-thromboglobulin level (p less than 0.005). Plasma beta-thromboglobulin concentrations are elevated in patients with coronary artery disease, suggesting ongoing platelet activation.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

Mutational analysis of the human immunodeficiency virus type 1 Rev transactivator: essential residues near the amino terminus.

The expression of certain mRNAs from human immunodeficiency virus type 1 (HIV-1) is controlled by the viral transactivator Rev, a nucleolar protein that binds a cis-acting element in these mRNAs. Rev is encoded by two viral exons that specify amino acids 1 to 26 and 27 to 116, respectively. Earlier studies have mapped essential regions of the protein that are encoded in the second exon. By further mutational analysis of Rev, we have now identified a novel locus encoded by the first exon that also is essential for transactivation in vivo. Defined by mutations at residues 14 to 20, this locus coincides with a cluster of positively charged and nonpolar amino acids that is conserved in Rev proteins of all known primate immunodeficiency viruses. Rev proteins that contained mutations at this site were defective in both nuclear localization and transactivation and did not function as trans-dominant inhibitors of wild-type Rev. Fusion of these mutants to a heterologous nuclear protein complemented the defect in localization but did not restore biological activity. Our findings suggest that this N-terminal locus may play a direct role in transactivation, perhaps contributing to essential protein-protein interactions or forming part of the RNA-binding domain of Rev.

Amino Acid Sequence↗
PubMed1989

Training residents to care for the mentally ill.

Recent changes in Royal College training requirements have highlighted the need for residency programs to be able to offer challenging and worthwhile experiences to their trainees in caring for the chronically mentally ill. This training should bring them into contact with patients at each stage of their illness and recovery and expose them to the different settings in which treatment or management takes place. Postgraduate programs face many problems in organizing this teaching that arise from the nature and course of long-term psychiatric illnesses, the organization of residency training programs, attitudes and preconceptions of residents and teachers and competing time demands. The authors review these problems, identify specific goals for the training and suggest strategies for achieving these goals. Expectations of postgraduate programs, clinical placements, supervisors and residents themselves are outlined.

Attitude of Health Personnel↗
PubMed1985

Red cell deformability and other haemorheological variables in stable coronary artery disease.

In this study, red cell deformability and other haemorheological variables were measured in 40 patients who underwent cardiac catheterization for the investigation of chest pain. The patients were divided into two groups - those with extensive disease and those with less extensive or no disease. Deformability was assessed by a filtration method. There were no significant differences in filterability, haematocrit, plasma viscosity or plasma fibrinogen between the two groups of patients. However, those with extensive disease had significantly higher blood viscosity than those with less extensive disease. Thus the study was able to demonstrate an association between blood viscosity and extent of coronary artery disease but not between the individual determinants of blood viscosity (red cell deformability, plasma fibrinogen and haematocrit) and extent of disease.

Adult↗
PubMed1984

Effects of clonidine and xylazine on body temperature in the rat.

Clonidine and xylazine injected intraperitoneally both produced a dose-dependent hypothermia in unanaesthetized, freely moving rats. The alpha 2-antagonist yohimbine produced an antagonism of the xylazine-induced hypothermia but a potentiation of the clonidine-induced hypothermia. The opioid antagonist naloxone had little effect on the xylazine hypothermia, but potentiated the clonidine hypothermia. It is concluded that whilst the two alpha 2-agonists produce a similar hypothermic effect in the rat, they are acting by different mechanisms.

Animals↗
PubMed1983

Behavior in nonorganic failure to thrive.

Twenty-one infants with failure to thrive were examined, shortly after hospital admission, for a set of eight noninterpersonal and six interpersonal behaviors identified as possibly being associated with nonorganic failure to thrive. The infants selected for study exhibited some of the target behaviors early in the course of hospitalization, and all were subsequently diagnosed as having nonorganic failure to thrive. The target behaviors include inactivity; irritability; posturing; lack of affect; rumination; excessive thumbsucking; disproportionate use of hands and fingers rather than arms, legs, and trunk; crying when approached; lack of or decreased vocalization; lack of cuddling; poor eye contact; lack of response to a human stimulus; and indifference to separation. Abnormal interpersonal behaviors were more common than abnormal noninterpersonal behaviors. Identification of these target behaviors may be valuable in diagnosing nonorganic failure to thrive, avoiding the necessity for expensive organic evaluations and providing for earlier social assessment and intervention.

Body Weight↗
PubMed1982

Insulin and beta receptor modulation of K homeostasis in nephrectomized dogs with hyperkalemia.

In nephrectomized dogs infused with 2 mEq KCl/kg/hr a homeostatic mechanism retards the development of hyperkalemia by transferring about 70% of the K load to intracellular fluid. beta Adrenergic receptor activity is importantly involved in the transfer process; halting it with propranolol reduces the proportion transferred to less than 35%. The addition of pancreatectomy increases the involvement of beta receptor activity; propranolol treatment now reduces the proportion transferred to less than 20%. Insulin treatment, on the other hand, not only improves transfer of a K load, it also alters the response to propranolol. Nephrectomized dogs treated with 2 U insulin/kg/hr deposit some 80% of the infused K in intracellular fluid. After beta receptor blockade, nearly 90% is transferred. The results suggest that in the K homeostatic mechanism of nephrectomized dogs, insulin and beta receptors may be reciprocally related. K transfer mediated by beta receptors improves after pancreatectomy, and insulin mediated K transfer improves after beta receptors are inactivated.

Aldosterone↗
PubMed1981

Antithrombin III deficiency in a Chinese family.

Familial antithrombin III deficiency, which is inherited by autosomal dominant transmission, is now well recognized as a cause of recurrent venous thromboembolism. Many such families have now been described, but few came from Asia. This report details a Chinese kindred with three members living in Sydney, two of whom are affected.

Adult↗
PubMed1977

Development of left ventricular hypertrophy in young spontaneously hypertensive rats after peripheral sympathectomy.

The effects of peripheral sympathectomy with nerve growth factor antiserum (NGFAS) on blood pressure, systemic hemodynamics, myocardial function, myocardial hypertrophy, and renin were studied in male spontaneously hypertensive (SH) rats of the Okamoto strain and normotensive control Kyoto-Wistar (WKY) rats. NGFAS prevented the developing of hypertension in the SH rats but did not alter blood pressure in the WKY rats. The NGFAS-treated SH rats developed the same hemodynamic abnormalities as the sham-treated rats, including increased peripheral vascular resistance and depressed cardiac output; Indices of left ventricular performance, including peak flow velocity, stroke power, stroke work, dP/dtmax, and flow acceleration (dF/dt), were diminished in the SH rats compared to the WKY rats. NGFAS treatment further depressed ventricular function in the SH rats, but had little effect on the WKY rats; Plasma renin activity in both the SH and WKY rats was unaffected by NGFAS treatment. Although NGFAS treatment effectively prevented the development of hypertension in the SH rats, it did not influence the development of left ventricular hypertrophy as reflected by increases in left ventricular mass, RNA, DNA, and hydroxyproline content. The data suggest that the development of myocardial hypertrophy and myocardial dysfunction in the SH rat is in part independent of hypertension and plasma renin activity.

Animals↗
PubMed1976

Altered angiotensin I conversion in pulmonary disease.

1. A specific method is described for the measurement of angiotensin I converting enzyme activity in plasma with 125 I-labelled angiotensin I used as substrate. 2. Converting enzyme activity in plasma from fifteen normal subjects, eleven patients with sarcoidosis, twelve patients with chronic obstructive pulmonary disease and three patients with shock lung was assayed by this technique. 3. Patients with sarcoidosis had increased plasma converting enzyme activity whether or not they were receiving steroid therapy. 4. Patients with chronic obstructive pulmonary disease and shock lung had decreased plasma converting enzyme activity, but extent of conversion did not correlate with the severity of the lung disease. 5. Converting enzyme activity in normal plasma could be completely inhibited by addition of exogenous angiotensin I in 0.5-2.5x107 times physiological concentration. Twice as much exogenous angiotensin I was needed to inhibit conversion completely in plasma from patients with sarcoidosis; one tenth as much in chronic obstructive pulmonary disease. These results indicate that plasma has a high capacity for angiotensin I conversion even in patients with pulmonary parenchymal disease. 6. Results suggest that plasma converting enzyme activity may be a reflection of pulmonary conversion and can be altered by pulmonary disease. 7. Measurement of plasma converting enzyme activity may be useful in studies designed to characterize the regulatory role of converting enzyme in the renin-angiotensin system and in cardiovascular homeostasis.

Angiotensin II↗
PubMed1975

The Pavlik harness for congenital dislocated hips.

The use of the Pavlik harness for treatment of congenital dislocated hips was begun at The University of Texas Medical Branch at Galveston, Texas, in August 1973. A method for rapid measurement and construction was subsequently developed. Data on length of use and case studies are presented.

Hip Dislocation, Congenital↗