Search PubMed⌕ Search

Biomedical subjects

M Foley

Publications and source records attributed to M Foley.

At least 37 records · Page 2Linked to original sources
PubMed1994

The Plasmodium falciparum protein RESA interacts with the erythrocyte cytoskeleton and modifies erythrocyte thermal stability.

The ring-infected erythrocyte surface antigen (RESA) associates with spectrin in the erythrocyte membrane (Foley, M., Tilley, L., Sawyer, W. H. and Anders, R. F. (1991) Mol. Biochem. Parasitol., 46, 137-148). A fragment of the RESA protein, which was expressed in Escherichia coli, was found to bind to inside-out vesicles of erythrocyte membranes in an apparently saturable manner. Upon extraction of inside-out vesicles with Triton X-100, the RESA fragment remained associated with the erythrocyte cytoskeleton. Using the technique of steady-state fluorescence polarisation, we have studied the thermal denaturation of fluorescein-labelled spectrin in the presence of recombinant RESA. We found that the RESA fragment partially protected spectrin against heat-induced conformational changes. Furthermore, erythrocytes infected with a RESA (-) laboratory strain (FCR3) were shown to be more susceptible to heat-induced fragmentation than erythrocytes infected with a RESA (+) strain of the parasite. RESA does not, however, appear to play an essential role in the invasion process per se as erythrocytes resealed to contain anti-RESA antibodies were efficiently invaded.

Animals↗
PubMed1994

Prospective review of 278 endoscopic carpal tunnel releases using the modified chow technique.

The results of 278 endoscopic carpal tunnel releases using the extrabursal dual portal Chow technique were analyzed prospectively. The majority of patients were pain free by the 57th postoperative day. The perioperative complication rate was 1.7%. The late complication rate was 2.8%. Two cases were converted to open carpal tunnel release. The average time to return to full-duty work was 65 days in those patients covered by worker's compensation, whereas it was 21 days in the privately insured (non-worker's compensation) patients. The endoscopic release of the transverse carpal ligament is an effective technique for the treatment of carpal tunnel syndrome with a low complications rate. Return to full employment requires more time in those patients covered by worker's compensation.

Adult↗
PubMed1994

Family support for heterosexual partners in HIV-serodiscordant couples.

OBJECTIVE: To ascertain the extent of family member support to heterosexual HIV-serodiscordant couples, and to identify associated sociodemographic and clinical characteristics. DESIGN: Discordant couples enrolled in a cohort study of heterosexual HIV transmission were interviewed with structured questionnaires to obtain sociodemographic data, family member awareness of HIV and perceived support from family members. Clinical characteristics were established by medical history, physical examination and laboratory tests. RESULTS: Awareness and support of family members were associated with sex of family member and HIV seropositivity, sex, education, and race of the partner. HIV-seropositive partners were more likely to have a sister aware than were HIV-negative partners (P = 0.01). More educated HIV-positive partners had fewer aware family members than less educated HIV-positive individuals (P = 0.02). Mothers of HIV-positive women were more often aware than mothers of all other partners (P = 0.04). Black HIV-negative partners had fewer aware family members than whites or Hispanics (P = 0.02). CONCLUSION: This research shows both encouraging and disturbing patterns of family awareness of HIV and support to serodiscordant partners.

Acquired Immunodeficiency Syndrome↗
PubMed1994

Fast MR imaging of the liver: quantitative comparison of techniques.

PURPOSE: To compare several techniques for fast magnetic resonance (MR) imaging of focal liver lesions. MATERIALS AND METHODS: Ninety patients (37 men and 53 women, aged 19-92 years [mean, 54 years]) with 137 focal liver lesions (56 metastases, 13 hepatocellular carcinomas, 52 hemangiomas, 16 cysts) underwent MR imaging with rapid acquisition spin-echo (RASE), T1-weighted fast low-angle shot (FLASH), turboFLASH, segmented turboFLASH, and T2-weighted conventional and turbo spin echo (SE). Images were analyzed for spleen-to-liver and lesion-to-liver signal difference-to-noise ratios (SD/Ns). RESULTS: Turbo SE T2-weighted imaging had the highest SD/N for spleen-to-liver (P < .01) and for lesion-to-liver (P < .02) contrast. Segmented T1-weighted turboFLASH imaging had the second highest SD/N for spleen-to-liver (P < .001) contrast and was better overall than other T1-weighted sequences for depicting liver lesions (P < .01). Results at segmented turboFLASH imaging were second best for hemangiomas (P < .01). For metastases, no significant difference was found for results with the T1-weighted sequences. CONCLUSION: Segmented T1-weighted turboFLASH and turbo SE T2-weighted imaging hae advantages over conventional techniques for liver imaging.

Carcinoma, Hepatocellular↗
PubMed1994

Refeeding hypertension in obese spontaneously hypertensive rats.

Very-low-calorie diets lower blood pressure acutely in obese humans and rats. However, refeeding after dietary restriction produces mild hypertension in rats. Refeeding hypertension was characterized in genetically obese spontaneously hypertensive rats (obese SHR, Koletsky rat), a model of genetic obesity and hypertension. Obese SHR were fed a restricted diet (Optifast) for 12 days, refed ad libitum for 28 days, dieted again for 12 days, and then refed 4 days and killed. Control obese SHR and lean SHR littermates were fed ad libitum continuously. Dietary restriction led to rapid weight loss followed by prompt regain to baseline weight after return to unrestricted food intake. Heart rate fell with institution of the low-calorie diet and returned to baseline on refeeding. Blood pressure became elevated during refeeding in dieted obese SHR relative to ad libitum fed obese SHR controls. The fall in blood pressure after ganglionic blockade with chlorisondamine was exaggerated in refed obese SHR, and cardiac beta-adrenergic receptors were downregulated. Both of these findings imply increased sympathetic tone. The left ventricular wall was thicker in the refed obese SHR than in the ad libitum fed obese SHR. Shorter cycles of weight loss and regain in lean SHR led to transient increases in blood pressure and heart rate. Cycles of dietary restriction and refeeding in obese SHR elicit sustained blood pressure elevation via sympathetic activation and exacerbate cardiac hypertrophy. Drastic fluctuations in nutrient intake may not be advantageous in hypertension.

Animals↗
PubMed1993

Patient education: bridging the gap between inpatient and ambulatory care.

This article describes a model curriculum of perinatal education designed to bridge the gap between prenatal ambulatory care education and labor and delivery, postpartum and well child care in a high-risk population of inner city women. The curriculum, which consists of broad-based, maternal-child health information, was developed, implemented, and evaluated through an interdisciplinary approach. The initiative narrowed the preexisting gap between departments, increased clients' knowledge, and promoted positive changes in clients' behavior. The breadth of the curriculum content addresses the unquestionable need for perinatal education that will enhance compliance and empower clients toward health maintenance.

Adolescent↗
PubMed1993

Effect of pacing strategy on cycle time trial performance.

Despite interest in competitive strategy by coaches and athletes, there are no systematically collected data regarding the effect of differences in pacing strategy on the outcome of middle distance (2-4 min duration) events. In this study different pacing strategies were evaluated using a 2-km time trial on a bicycle attached to a wind load simulator. Well-trained subjects (N = 9) performed five separate time trials with the pace during the first 50% of the trial experimentally constrained within the usual real world range from very slow (approximately 55% of best time) to very fast (approximately 48% of best time). Serial VO2 was measured to estimate the oxidative contributions to the trial and accumulated O2 deficit and postexercise blood lactate measured to estimate the anaerobic contribution to the trial. The evenly paced trial (first 1 km = 50.9% final time) produced the fastest total time. The starting pace to final time relationship was described by a U shaped second order polynomial curve with the nadir for final time at a starting pace of 51% of best total time. There were no systematic differences in serial VO2, accumulated O2 deficit, or postexercise lactate that could account for the pacing related variations in performance. The data support the concept of relatively even pacing in middle distance events with negative consequences for even small variations in this strategy.

Analysis of Variance↗
PubMed1992

Using patient reports to assess hospital treatment of persons with AIDS: a pilot study.

Providing efficacious, compassionate, and efficient medical care to persons with HIV infection is one of the greatest challenges that will face US hospitals this decade. Unfortunately, there have been almost no studies of how organizational arrangements are related to the quality of care. We developed an interview protocol and conducted a pilot study to evaluate the instrument's ability to detect differences in selected interpersonal aspects of care provided to persons with AIDS. We evaluated the care received in two different treatment models in a major teaching hospital: a designated AIDS unit and general medical beds. We assessed several areas of patient care that are clinically important and that patients can evaluate: communication between patients and providers, patient education, respect for patient preferences, emotional support, involvement of family and friends, trust and confidence, physical care, pain management, AIDS knowledge, perceived segregation, confidentiality, and financial information. Patients generally were very satisfied with their hospital care, but many reported problems with certain aspects of their care. The instrument used detected differences between the care reported by patients treated in general hospital beds and in a designated AIDS unit in several specific aspects of care.

Acquired Immunodeficiency Syndrome↗
PubMed1992

The timing of delivery in diabetic pregnancy: a 10-year review.

The approach of term in the pregnancy of a diabetic woman is a time of anxiety for patient and physician alike. The impact of a conservative approach to the timing of delivery is outlined in this review of the clinical course and outcome of 276 pregnancies of diabetic women, delivered at the National Maternity Hospital, Dublin between 1981 and 1990. The mean gestation at delivery was 39 weeks, 229 patients (83%) delivered at or beyond 38 weeks and 112 patients (41%) delivered at or beyond 40 weeks. The overall induction of labour rate was 27% and the elective Caesarean section rate was 19%. Sixty seven percent of patients achieved a normal delivery, the forceps rate was 5%, and 28% of patients were delivered by Caesarean section. There were 16 perinatal deaths in the series, with 7 due to lethal malformations. There were 5 deaths of normally formed infants occurring at or beyond 38 weeks' gestation. All of these 5 deaths had been preceded by clinically apparent polyhydramnios or macrosomia and recognized poor control. This study stresses the value of strict diabetic control in the management of diabetic pregnancy and highlights the significance of polyhydramnios and macrosomia as indicators of risk approaching term in diabetic pregnancy.

Adolescent↗
PubMed1992

Should mono- or poly-unsaturated fats replace saturated fat in the diet?

The effects of diets differing in saturated, monounsaturated and polyunsaturated fatty acid composition (SAFA, MUFA and PUFA, respectively) on plasma lipoproteins and factor VIIc were investigated in 28 middle-aged men and women with mild to moderate hyperlipidaemia. The subjects were stabilized on a diet with a total fat content fairly typical of New Zealand, containing approximately 40% energy as fat, before entering a randomized cross-over trial of diets high in PUFA (20% energy; SAFA and MUFA 10% each) or a high MUFA diet (20% energy; SAFA and PUFA 10% each). After 6-week periods on each diet the subjects returned to a high SAFA diet. Body weight and blood pressure remained unchanged during the study. Total and LDL cholesterol, HDL cholesterol and the HDL2 subfraction were significantly lower on both the MUFA and the PUFA diet than on SAFA. However, there were no statistically significant differences in lipoprotein concentrations on the MUFA and PUFA diet. Factor VIIc concentrations were similar on the three diets. The proportion of PUFA in a MUFA diet appears to be a major determinant of the relative lipoprotein response to such a diet. In order to avoid a reduction in HDL-C when replacing SAFA with MUFA it may be necessary to ensure that PUFA does not provide more than about 8% total energy. Thus careful planning is needed to identify the most appropriate foods to replace those rich in SAFA in diets designed to reduce the lipoprotein-mediated risk of coronary heart disease.

Aged↗
PubMed1991

The ring-infected erythrocyte surface antigen of Plasmodium falciparum associates with spectrin in the erythrocyte membrane.

The malaria parasite Plasmodium falciparum synthesises a protein, RESA, which associates with the membrane of newly invaded erythrocytes. Using spent supernatants from P. falciparum growing in culture as a source of soluble RESA we have developed an assay to examine the characteristics of RESA binding to the erythrocyte membrane in vitro. RESA associated with the Triton X-100 insoluble proteins on the inner face of the host erythrocyte membrane but did not bind to the outer surface of intact erythrocytes. Other proteins present in culture supernatants did not bind to the erythrocyte membrane. RESA was co-sedimented with the ternary complex formed between actin, spectrin and band 4.1 and co-precipitated with spectrin precipitated with anti-spectrin antibodies. The extent of association between RESA and the inner face of the erythrocyte membrane was reduced by the inclusion of excess purified spectrin in the assay. Thus, RESA appears to be associated with spectrin in the erythrocyte membrane skeleton.

Animals↗
PubMed1991

Effects of venous return on respiratory response.

This study reevaluated the link between the rate of CO2 flow to the pulmonary circulation and changes in cardiac output to the respiratory responses following leg lifting in normal man subjects. Thirty healthy subjects (mean age = 22.2 years) were subjected to the experimental maneuver which increased venous return to the right heart. Cardiac output was significantly increased and with it a significant increase in CO2 output by the lungs was found. These results were associated with a significant increase in expired ventilation. The rapidity of the ventilatory response to the increase in cardiac output suggests the existence of pressoreceptors localized in the pulmonary circulation which, when activated, results in the elicitation of respiratory reflexes. The end result is an adjustment in the respiratory response in accordance with venous return.

Adult↗
PubMed1990

Rotational dynamics of the integral membrane protein, band 3, as a probe of the membrane events associated with Plasmodium falciparum infections of human erythrocytes.

Time-resolved phosphorescence anisotropy was used to study the molecular organisation of band 3 in the erythrocyte membrane. Three different rotational relaxation regimes of mobile band 3 were resolved. These populations may represent different aggregation states of band 3 within the membrane, or they may result from association of band 3 with other proteins at the cytoplasmic surface. The polycation spermine decreases the apparent mobility of band 3 by a mechanism that does not involve the underlying cytoskeleton. A monoclonal antibody directed against the cytoplasmic portion of band 3 can also cause an increase in the immobile fraction of band 3 molecules. This monoclonal antibody will inhibit invasion of erythrocytes by malaria parasites. Membranes prepared from erythrocytes infected with mature stages of the malaria parasite, Plasmodium falciparum, show altered dynamic properties corresponding to a marked restriction of band 3 mobility.

Animals↗
PubMed1990

The ring-infected erythrocyte surface antigen protein of Plasmodium falciparum is phosphorylated upon association with the host cell membrane.

The ring-infected erythrocyte surface antigen (RESA) is a 155-kDa malarial polypeptide which is released from merozoites and becomes associated with the erythrocyte membrane at the time of invasion. Inside-out vesicles (IOVs) prepared from Plasmodium falciparum-infected erythrocytes contain RESA, presumably bound to the membrane skeleton, as it is largely insoluble in Triton X-100. When these IOVs were incubated with [gamma-32P]ATP, a 155-kDa polypeptide was labeled in IOVs from infected, but not from uninfected erythrocytes. Immunoprecipitation using specific rabbit antisera confirmed that RESA is indeed a phosphoprotein. Phosphoamino acid analysis revealed phosphoserine and a small amount of phosphothreonine, but no phosphotyrosine. Labeling of intact parasitized erythrocytes with inorganic [32P]phosphate for several hours in culture resulted in RESA in Triton-insoluble extracts being phosphorylated. Labeling of synchronized parasites showed that RESA was phosphorylated only when it became associated with the erythrocyte membrane, and although RESA was abundant in mature parasites, it was not phosphorylated. RESA, released into the culture supernatants during the growth of P. falciparum, bound to IOVs prepared from normal uninfected erythrocytes, and subsequent labeling with [gamma-32P]ATP resulted in the phosphorylation of RESA. The evidence suggests that RESA is phosphorylated by an erythrocyte membrane kinase and probably not by a parasite-encoded enzyme.

Adenosine Triphosphate↗