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Biomedical subjects

P Browne

Publications and source records attributed to P Browne.

At least 19 recordsLinked to original sources
PubMed2001

Physical activity patterns in a nationally representative sample of adults in Ireland.

OBJECTIVE: To evaluate habitual levels of physical activity in a nationally representative sample of adults in Ireland. DESIGN: Cross-sectional survey using a self-administered questionnaire. Usual levels of work, recreational and household activities were evaluated in relation to anthropometric, demographic and socio-economic characteristics. The amount and intensity of all activities were quantified by assigning metabolic equivalents (METS) to each activity. SETTING: Republic of Ireland and Northern Ireland, 1997-1999. SUBJECTS: Random sample of 1379 adults aged 18-64 years. RESULTS: Men were approximately twice as active in work and recreational activity (139.7 +/- 83.9 METS) as women (68.5 +/- 49.8 METS; P<0.001) but women were three times more active in household tasks (65.9 +/- 58.7 METS vs. 22.6 +/- 24.6 METS; P<0.001). Overall levels of physical activity declined with increasing age, particularly leisure activity in men. In women the decline in work activity was offset by spending more time in household pursuits. Twenty-five per cent of the subjects were extremely overweight (body mass index (BMI>28 kg m(-2)) or obese (BMI >30 kg m (-2)). Fewer obese subjects reported higher levels of work and leisure activities. However, a higher percentage of obese women reported participation in the higher levels of household activities. Participation rates in recreational activities were low. Walking was the most important leisure activity of both men (41%) and women (60%). In terms of hours per week spent in vigorous physical activity, men were more active than women, professional and skilled non-manual women were more active than women in other social classes, and younger subjects (aged 18-35 years) were more active than older subjects. CONCLUSIONS: The holistic approach used in the assessment of physical activity in this study has revealed important and subtle differences in the activity patterns of men and women. Failure to fully characterise the respective activity patterns of men and women could lead to ill-informed public health policy aimed at promoting and sustaining lifetime habits of physical activity. The results suggest that simple population-focused programmes to promote physical activity are unlikely to offer the same chance of long-term success as more sensitive and individualised strategies.

Adolescent↗
PubMed2000

Volunteers. Time is money.

An audit of volunteers' work at a district general hospital showed its value to be more than 127,000 Pounds. For every 1 Pound the trust invested in volunteers there was a return of 5.57 Pounds. The research showed that volunteers gave 35,464 hours of their free time to the hospital last year. The national average is 27,000 hours per trust.

Hospital Volunteers↗
PubMed2000

An outbreak of multiply resistant Serratia marcescens: the importance of persistent carriage.

An outbreak of multi-resistant Serratia marcescens involving 24 patients occurred in a bone marrow transplant and oncology unit, from September 1998 to June 1999, of whom 14 developed serious infection. This is the first such outbreak described in a BMT unit. All isolates demonstrated the same antimicrobial susceptibility pattern and were the same unusual serotype O21:K14. The antimicrobial susceptibility profile showed reduced susceptibility to ciprofloxacin, gentamicin and piperacillin-tazobactam. As the latter two antimicrobials are part of our empiric therapy for febrile neutropenia, they were substituted with meropenem and amikacin during the outbreak. Investigation revealed breaches in infection control practices. Subsequently, the outbreak was contained following implementation of strict infection control measures. A prominent feature of the outbreak was prolonged carriage in some patients. These patients may have acted as reservoirs for cross-infection. This report also indicates that patients who become colonised with Serratia marcescens may subsequently develop invasive infection during neutropenic periods.

Adult↗
PubMed2000

Experimental investigation of the steady flow downstream of the St. Jude bileaflet heart valve: a comparison between laser Doppler velocimetry and particle image velocimetry techniques.

This study investigates turbulent flow, based on high Reynolds number, downstream of a prosthetic heart valve using both laser Doppler velocimetry (LDV) and particle image velocimetry (PIV). Until now, LDV has been the more commonly used tool in investigating the flow characteristics associated with mechanical heart valves. The LDV technique allows point by point velocity measurements and provides enough statistical information to quantify turbulent structure. The main drawback of this technique is the time consuming nature of the data acquisition process in order to assess an entire flow field area. Another technique now used in fluid dynamics studies is the PIV measurement technique. This technique allows spatial and temporal measurement of the entire flow field. Using this technique, the instantaneous and average velocity flow fields can be investigated for different positions. This paper presents a comparison of PIV two-dimensional measurements to LDV measurements, performed under steady flow conditions, for a measurement plane parallel to the leaflets of a St. Jude Medical (SJM) bileaflet valve. Comparisons of mean velocity obtained by the two techniques are in good agreement except for where there is instability in the flow. For second moment quantities the comparisons were less agreeable. This suggests that the PIV technique has sufficient temporal and spatial resolution to estimate mean velocity depending on the degree of instability in the flow and also provides sufficient images needed to duplicate mean flow but not for higher moment turbulence quantities such as maximum turbulent shear stress.

Biomedical Engineering↗
PubMed1998

Cushing syndrome due to surreptitious glucocorticoid administration.

We report a case of subtle Cushing syndrome in a Pakistani man who self-treated his asthma with a potent long-acting oral glucocorticoid (betamethasone disodium phosphate [Bentelan]) for more than 30 years. He presented with cushingoid features, insulin resistance, and refractory hypertension. Laboratory evaluation revealed undetectable cortisol levels and suppression of the hypothalamic-pituitary-adrenal axis. The patient obtained the drug from his country of origin, with no understanding of the potential adverse effects imposed by long-term use of steroids. He is now being slowly weaned off the drug. The apparent widespread availability, access, and abuse of such potent steroids are a cause of concern in developing countries. We suggest that physicians in the United States be aware of the potential abuse of such potent drugs in all populations, including immigrants.

Asthma↗
PubMed1998

Interferon-alpha restores beta1-integrin-dependent, collagen-mediated platelet aggregation in a patient with chronic myelogenous leukemia.

Although interferon-alpha (IFN-alpha) induces hematologic remissions in 70% to 80% of patients with chronic myelogenous leukemia (CML) and complete or near-complete cytogenetic remissions in 10% to 20% of patients, the exact mechanisms underlying these clinical results remain unclear. We have hypothesized that IFN-alpha acts at least in part through restoration of beta1-integrin function on malignant hematopoietic progenitors that can promote adhesion of malignant progenitors to the marrow microenvironment. This may then restore microenvironmental inhibition of progenitor proliferation and induce tumor dormancy. We demonstrate that IFN-alpha administration to a patient suffering from a clinically severe bleeding diathesis reversed the defective collagen-mediated aggregation of platelets expressing normal numbers of functionally inactive collagen receptors. This is the first in vivo demonstration that IFN-alpha can up-regulate the function of adhesion receptors in CML and supports the premise that IFN-alpha induces remissions by restoring normal integrin-mediated interactions between progenitors and microenvironmental components.

Collagen↗
PubMed1998

The molecular pathobiology of cell membrane iron: the sickle red cell as a model.

The molecular pathobiology of membrane-associated iron is clearly illustrated by the sickle red blood cell. The cytosolic aspect of the membranes of these cells carries several discrete iron compartments, including denatured hemoglobin and free heme, as well as molecular iron associated with membrane aminophospholipid and denatured globin. Affinity of the membrane for molecular iron is extraordinarily high and predicted to keep cytosolic free iron concentration < 10(-20) M. Membrane iron is bioactive and able to valence cycle, thus serving as a catalyst for generation of highly reactive hydroxyl radical. As a consequence of this oxidative biochemistry at the cytosol/membrane interface, multiple membrane defects arise that are of pathophysiologic importance. Thus, sickle red cells provide a pathobiologic paradigm for the membrane-damaging effect of iron-mediated targeting of oxidative damage at a sub-cellular level. This is relevant to a variety of biologic conditions accompanied by decompartmentalization of iron.

Anemia, Sickle Cell↗
PubMed1998

How SelectCare selected a system.

Selecting a managed care system in the absence of a clearly defined business strategy is like driving across the country without a road map. But SelectCare didn't let that stop them. Here's their seven-step methodology.

Chronology as Topic↗
PubMed1998

Intravascular large B-cell lymphoma: the CD5 antigen is expressed by a subset of cases.

The CD5 antigen is a T-cell associated marker that is also usually expressed by two B-cell neoplasms, chronic lymphocytic leukemia/small lymphocytic lymphoma and mantle cell lymphoma. We observed CD5 antigen expression in a subset of cases of intravascular large B-cell lymphoma (IVLBL), and we report here five cases. The patients, two men and three women, ranged in age from 59 to 81 years. Biopsy specimens were obtained from kidney, lung, bone marrow, abdominal wall, and neck, the latter involving a lymphangioma. All of the cases had histologic features typical of IVLBL, with large and atypical lymphoid cells located predominantly within blood vessels. Immunohistochemical studies performed using routinely fixed, paraffin-embedded tissue sections showed that the neoplastic cells were B cells, positive for the CD20 antigen and negative for the CD3 or CD43 antigens. All cases were also positive for the CD5 antigen. One case had an immunoglobulin heavy chain gene rearrangement shown by using a polymerase chain reaction method. The finding of CD5 antigen expression in a subset of IVLBL cases adds to other evidence in the literature suggesting that IVLBL is a heterogeneous entity. We considered the possibility that these cases were related to or represented unusual histologic forms of transformation from either chronic lymphocytic leukemia/small lymphocytic lymphoma or mantle cell lymphoma. All of the cases, however, were negative for the CD23 antigen and cyclin D1 (bcl-1) protein, which is evidence against this interpretation. The biologic significance of CD5 antigen expression in cases of IVLBL is uncertain. These neoplasms might arise from a separate lineage of CD5-positive B cells or from a specific, early stage of B-cell differentiation. Alternatively, some investigators have suggested that CD5 antigen expression by B cells is a marker of activation.

Aged↗
PubMed1997

Circulating activated endothelial cells in sickle cell anemia.

BACKGROUND: The vascular wall participates in the pathogenesis of sickle cell disease. To determine whether the endothelium is activated in this disease, we studied the number, origin, and surface phenotype of circulating endothelial cells in patients with sickle cell anemia. METHODS: We used immunohistochemical examination of buffy-coat smears to enumerate circulating endothelial cells, and we evaluated the surface phenotype by applying preparations of circulating endothelial cells. An immunofluorescence microscopy panel of antibodies was used, including a specific anti-endothelial-cell antibody, P1H12. RESULTS: Mean (+/-SD) numbers of circulating endothelial cells in normal blood donors, patients with sickle cell trait, and patients with hemolytic anemias not due to hemoglobin S were 2.6+/-1.6, 3.0+/-2.6, and 2.0+/-0.8 per milliliter of whole blood, respectively. Patients with sickle cell anemia who presented with acute painful episodes had 22.8+/-18.2 circulating endothelial cells per milliliter of blood (P<0.001 for the comparison with normal donors), and patients with no such events within one month before or after blood sampling had 13.2+/-11.8 circulating endothelial cells per milliliter of blood (P=0.002 for the comparison with normal donors and P=0.019 for the comparison with patients with acute events). Serial observations of three patients showed a tendency toward higher levels of circulating endothelial cells at the onset of acute painful crises. The average viability of circulating endothelial cells was 66+/-30 percent. In patients with sickle cell anemia, regardless of clinical status, the circulating endothelial cells were predominantly microvascular in origin (CD36-positive), and most of the cells expressed four markers of endothelial-cell activation: intercellular adhesion molecule 1, vascular-cell adhesion molecule 1, E-selectin, and P-selectin. CONCLUSIONS: Our studies suggest that the vascular endothelium is activated in patients with sickle cell anemia, regardless of the patients' clinical status. Adhesion proteins on activated endothelial cells may have a role in the vascular pathology of sickle cell disease.

Adolescent↗
PubMed1997

Diploid hydatidiform moles with fetal red blood cells in molar villi. 1--Pathology, incidence, and prognosis.

It is believed that fetal development does not occur in complete mole (CM); when present, it is usually interpreted as proof of partial mole (PM), in most cases a triploid conception with a low incidence of persistent trophoblastic disease (PTD). However, histological examination of 3180 moles in 8 years showed 60 moles (1.8 per cent) with features of CM and either embryonic tissues or amnion in the sample. Flow cytometry (FC) in 40 showed diploid complement in all. In ten of the 40, there was evidence of a twin; in 17, there was only amnion, which could belong to a twin; in the remaining 13, there was no evidence of a twin and nucleated fetal red blood cells (FRCs) were seen within molar vessels in ten (0.3 per cent). Seven of the 40 patients (17.5 per cent) and one of the ten with FRCs in villi (10 per cent) developed PTD, an incidence comparable to that of CM. Genetic studies in seven of these tea are reported separately. Finding fetal tissues with a mole or FRCs in molar vessels is not enough to classify it as PM, since it can be a CM with a twin, fetal development CM, or possibly a third type of mole. These rare diploid moles with fetal tissues have histological appearances and prognosis similar to those of CM.

Adult↗
PubMed1997

Abnormal immunoreactivity of the E-cadherin-catenin complex in gastric carcinoma: relationship with patient survival.

BACKGROUND & AIMS: The E-cadherin-catenin complex plays a critical role in the maintenance of normal tissue architecture. Mutation of any of its components is believed to result in loss of cell-cell adhesion and contribute to neoplasia. The aim of this study was to examine the expression of E-cadherin and alpha-, beta-, and gamma-catenin in gastric carcinoma and dysplasia and determine any relationship with tumor characteristics and survival. METHODS: Immunoperoxidase staining of E-cadherin and alpha-, beta-, and gamma-catenin was performed using 89 gastric carcinomas, lymph node metastases, and gastric biopsy specimens from 14 patients with dysplasia and 10 healthy controls. RESULTS: Membranous staining was observed in control biopsy specimens for all components of the complex. Up to 57% of gastric dysplasia and 90% of tumors stained abnormally for one or more components of the cadherin-catenin complex. Abnormal E-cadherin and gamma-catenin staining occurred more frequently in diffuse than intestinal tumors (P < 0.0005 and < 0.05, respectively). No association with tumor grade or stage was found. A survival advantage was noted in intestinal and diffuse tumors retaining membranous expression of beta-catenin, independent of tumor type, grade, or stage (P < 0.005). CONCLUSIONS: Abnormal expression of the E-cadherin-catenin complex occurs frequently in gastric carcinoma. The close correlation with poor survival suggests that abnormal beta-catenin may be a useful prognostic marker.

Adult↗
PubMed1996

A clinical, histopathological and flow cytometric study of 149 complete moles, 146 partial moles and 107 non-molar hydropic abortions.

We have compared the clinical and histological features of 149 complete moles with 146 triploid partial moles and 107 diploid non-molar hydropic abortions initially registered as moles for human chorionic gonadotrophin (hCG) follow-up. Forty-one patients with complete moles, five with partial moles and one with hydropic abortion received chemotherapy for hCG elevations interpreted as persistent trophoblastic disease. Complete moles were aborted or were evacuated significantly earlier than partial moles (means of 12.1 and 15.4 weeks; P < 0.001) and hydropic abortions significantly earlier than complete moles (mean 10.7 weeks; P < 0.005). The means of the highest recorded hCG were higher in complete moles (184,056 i.v.) than in partial moles (66,259 i.v.) and hydropic abortion (7942 i.v.). When hCG became normal without chemotherapy, this occurred earlier in patients with hydropic abortion than in those with partial moles (means of 46.7 days and 62.8 days; P < 0.001) and earlier in partial moles than in complete moles (mean 78.3 days; P < 0.005). The incidence of partial moles was comparable throughout fertile years but rose to 1.9 times the average after 40 years. Complete moles were commoner between 14 and 25 years and after 35 years, reaching 4.8 times the average after 40 years. Hydropic abortions were rare before 25 years and increased with age to 12 times the average after 40 years. Stromal karyorrhexis and shape of villi, before they become hydropic, discriminate well between complete and partial mole. Hydrops increased and vascularity decreased with molar age and the presence of non-hydropic villi or vessels did not discriminate between partial mole and the younger complete moles evacuated nowadays.

Abortion, Spontaneous↗
PubMed1995

A comparison of the effects of human and ovine corticotropin-releasing hormone on the pituitary-adrenal axis.

To compare the clinical efficacy of ovine and human sequence corticotropin-releasing hormone (CRH), we examined the effects of both peptides on ACTH and cortisol secretion in normal human volunteers, obese subjects, and patients with pituitary-dependent (Cushing's disease) and adrenal-dependent Cushing's syndrome. All subjects in each group were studied twice in random order. One hundred micrograms of CRH were administered as an iv bolus through an in-dwelling forearm cannula at 0930 h, and thereafter, blood was drawn every 15 min for 2 h for the measurement of ACTH and cortisol. In the normal subjects, the peak ACTH, peak incremental ACTH, and mean area under the curve after CRH treatment were greater with ovine CRH than human CRH, although there was no difference in the cortisol response, however it was analyzed. There was no difference in the ACTH or cortisol response to the two preparations in the obese subjects, and no significant difference was found, for either cortisol or ACTH, between obese subjects and normal volunteers. With both varieties of CRH, Cushing's disease resulted in greater responses for ACTH and cortisol than those seen in the other 2 groups (P < 0.001 for all comparisons), but there was no difference between the sequences. However, a significant cortisol response, defined as an increase of greater than 4 times the coefficient of variation of the assay (24%), was seen in all 10 Cushing's patients with human CRH, but in only 8 with ovine CRH. In 3 patients with adrenal tumors, serum cortisol did not change after the administration of either preparation, whereas plasma ACTH remained undetectable throughout the study. We suggest that although ovine sequence CRH causes more prolonged and greater ACTH, and possibly cortisol, secretion compared to human CRH, the discriminatory value of the CRH test, in terms of either the diagnosis or differential diagnosis of Cushing's syndrome, is comparable for the two peptide sequences.

Adrenocorticotropic Hormone↗
PubMed1994

Analysis of the regulation of penicillin biosynthesis in Aspergillus nidulans by targeted disruption of the acvA gene.

To analyse the regulation of the biosynthesis of the secondary metabolite penicillin in Aspergillus nidulans, a strain with an inactivated acvA gene produced by targeted disruption was used. acvA encodes delta-(L-alpha-aminoadipyl)-L-cysteinyl-D-valine synthetase (ACVS), which catalyses the first step in the penicillin biosynthetic pathway. To study the effect of the inactivated acvA gene on the expression of acvA and the second gene, ipnA, which encodes isopenicillin N synthase (IPNS), A. nidulans strain XEPD, with the acvA disruption, was crossed with strain AXB4A carrying acvA-uidA and ipnA-lacZ fusion genes. Ascospores with the predicted non-penicillin producing phenotype and a hybridization pattern indicating the presence of the disrupted acvA gene, and the fusion genes integrated in single copy at the chromosomal argB locus were identified. Both fusion genes were expressed at the same level as in the non-disrupted strain. Western blot analysis (immunoblotting) revealed that similar amounts of IPNS enzyme were present in both strains from 24 to 68 h of a fermentation run. In the acvA disrupted strain, IPNS and acyl-CoA: 6-aminopenicillanic acid acyltransferase (ACT) specific activities were detected, excluding a sequential induction mechanism of regulation of the penicillin biosynthesis gene ipnA and the third gene aat.

Acyltransferases↗
PubMed1993

A circadian distribution to febrile episodes in neutropenic patients.

Four-hourly temperature charts relating to 63 febrile neutropenic episodes in 32 patients were assessed for a circadian distribution to the onset of fever (> 37.5 degrees C) using the Edward's test. A highly significant distribution was found with the maximum incidence of febrile events between the hours of 5 p.m. and midnight (acrophase 9.30 p.m.). Patients were 5.53 times more likely to develop fever at 9.30 p.m. that 9.30 a.m.

Adolescent↗
PubMed1992

A new method for the determination of the characteristic shape of an isokinetic quadriceps femoris muscle torque curve.

It has been suggested that visual analysis of isokinetic quadriceps femoris muscle torque curve (TC) shapes may have potential use in the diagnosis and prognosis of knee pathologies. The primary purpose of this pilot study was to develop a method for analyzing the shape of an isokinetic TC. Our method normalizes and averages the TC, and then uses curvilinear analysis of the TC shape to aid in diagnosis and prognosis. For demonstration, the method was applied to isokinetic quadriceps femoris muscle TC data collected using a LIDO digital dynamometer from 25 healthy volunteer subjects and retrospectively acquired from the uninvolved limbs of 37 patients with unilateral knee pathologies. The preliminary results revealed (1) that a common quadriceps femoris muscle TC shape existed for the volunteer group at 60 degrees and 180 degrees/s; (2) that the uninvolved limbs of the patient group exhibited the same shape at 60 degrees/s, but not at 180 degrees/s; and (3) that the quadriceps femoris muscle TC shape demonstrated no significant differences with respect to limb dominance or gender for either group. Further testing of this quantitative method on a larger sample is needed to determine its usefulness in the analysis and implications of TC shape concerning pathology and diagnosis.

Adult↗