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Biomedical subjects

B Wilkins

Publications and source records attributed to B Wilkins.

At least 19 recordsLinked to original sources
PubMed2003

Anthropometry of young competitive sport rock climbers.

BACKGROUND: Adult elite competitive rock climbers are small in stature with low body mass and very low body fat percentage. These characteristics have generated concern that young climbers may attempt body mass reduction to extreme levels with adverse consequences for health and performance. No published anthropometry data for young competitive climbers exist. OBJECTIVE: To describe the general anthropometric characteristics of junior US competitive rock climbers. METHODS: Ninety subjects (mean (SD) age 13.5 (3.0) years) volunteered to participate. All competed at the Junior Competition Climbers Association US National Championship. Anthropometric variables, including height, mass, body mass index (BMI), arm span, biiliocristal and biacromial breadths, skinfold thickness at nine anatomical sites, forearm and hand volumes, and handgrip strength, were measured. Selected variables were expressed as ratio values and as normative age and sex matched centile scores where appropriate. A control group (n=45) of non-climbing children and youths who participated in a variety of sports activities, including basketball, cross country running, cross country skiing, soccer, and swimming, underwent the same testing procedures in the Exercise Science Laboratory of Northern Michigan University. RESULTS: Mean (SD) self reported climbing ability was 11.80 (1.20), or about 5.11 d on the Yosemite decimal system scale. The mean (SD) experience level was 3.2 (1.9) years, and subjects competed in 10 (5) organised competitions over a 12 month period. Despite similarity in age, there were significant differences (p<0.01) between climbers and control subjects for height, mass, centile scores for height and mass, ratio of arm span to height ("ape index"), biiliocristal/biacromial ratio, sum of seven and sum of nine skinfolds, estimated body fat percentage, and handgrip/mass ratio. Despite significantly lower skinfold sums and estimated body fat percentage, no differences were found between climbers and controls for absolute BMI or BMI expressed as a centile score. CONCLUSIONS: Young competitive climbers have similar general anthropometric characteristics to elite adult climbers. These include relatively small stature, low body mass, low sums of skinfolds, and high handgrip to mass ratio. Relative to age matched athletic non-climbers, climbers appear to be more linear in body type with narrow shoulders relative to hips. Differences in body composition exist between climbers and non-climbing athletes despite similar BMI values.

Adolescent↗
PubMed2002

A single-centre study of treatment outcomes and survival in 120 patients with peripheral T-cell non-Hodgkin's lymphoma.

We conducted a retrospective study of treatment outcomes and survival in 120 consecutive, unselected patients with peripheral T-cell non-Hodgkin's lymphoma, presenting at a single centre over a 20-year period. Cases met the criteria of the Revised European-American Lymphoma (REAL) Classification and patients with peripheral T-cell lymphoma of the following subtypes were included: anaplastic large T-cell lymphoma (ALCL), angioimmunoblastic T-cell lymphoma (AILD), peripheral T-cell lymphoma unspecified (PTCLu), and intestinal T-cell lymphoma (ITCL). The study population consisted of 120 patients with a presenting diagnosis of peripheral T-cell lymphoma. Cases that had been previously confirmed as T-cell lymphoma at formal pathology review were identified from the lymphoma database of this institution. Staging investigations, treatment type and outcomes were taken from patient records. For each subtype, clinical characteristics, response to initial treatment, duration of response and any subsequent relapse were recorded. Overall, relapse, and progression-free survival figures were calculated. The ALCL group had the best response rate to first line treatment 19 of 22 (86 percent) while the AILD group had the lowest response 12 of 29 (41 percent). Relapse rates were PTCLu 13 of 35 (37 percent), ITCL 10 of 34 (29 percent), ALCL 6 of 22 (27 percent) and AILD 7 of 29 (24 percent). In terms of median overall survival, a significantly superior survival was demonstrated for the ALCL group (7.05 years) compared to the remaining three groups. The ALCL group had the lowest risk of death while the ITCL group had the highest risk (hazard ratio: 2.82). Five-year survival rates were estimated to be ALCL 60 percent, PTCLu 40 percent, AILD 30 percent and ITCL 25 percent. This single-centre study demonstrated different outcomes for each group with significant differences in overall survival rates. These findings support the clinical utility of the REAL lymphoma classification in respect to the PTCL subgroups included in this study.

Adult↗
PubMed2001

Teenage coma.

Explore the source record for details and available documents.

Adolescent↗
PubMed2001

Fatal disseminated fusarium infection in acute lymphoblastic leukaemia in complete remission.

Fusarium species are increasingly recognised as serious pathogens in the immunocompromised. The outcome in the context of persistent severe neutropenia has been almost universally fatal. However, there have been several case reports of successful treatment if neutrophil recovery can be achieved. This report presents the case of a fatality that occurred despite neutrophil recovery. A 67 year old man developed disseminated fusariosis during the neutropenic phase of induction chemotherapy for acute lymphoblastic leukaemia. Fusarium dimerum was isolated from blood cultures. This species is highly unusual and very few case reports exist in the literature. An initial response to amphotericin treatment coincided with neutrophil recovery but a subsequent relapse occurred, despite adequate neutrophil counts, which proved fatal. It is postulated that reseeding of the blood from an occult site, namely the right vitreum in this case, led to this secondary relapse despite achieving complete leukaemic remission.

Aged↗
PubMed2000

Hepatic stellate cells express the low affinity nerve growth factor receptor p75 and undergo apoptosis in response to nerve growth factor stimulation.

We have examined the expression of p75, a member of the TNF receptor superfamily in hepatic stellate cells (HSC) and pancreatic stellate cells (PSC). Activated HSC and PSC were demonstrated by Western blot analysis to express p75. p75 was immunolocalized to cells with a myofibroblast-like morphology in the fibrotic bands of six fibrotic and cirrhotic liver biopsies and three biopsies of fibrotic human pancreas. Immunostaining of parallel sections indicated that these cells were alpha-smooth muscle actin-positive, identifying them as activated HSC and PSC, respectively. HSC apoptosis in tissue culture in the presence of serum was quantified after addition of 0.1 to 100 ng/ml of nerve growth factor (NGF) a ligand for p75, by in situ counting of apoptotic bodies after addition of acridine orange. HSC demonstrated a significant increase in apoptosis in response to 100 ng/ml NGF (0.05 > P by Wilcoxon's rank; n = 7) after 24 hours. NGF 100 ng/ml had no effect on HSC proliferation, but reduced total HSC DNA by 19% relative to control after 24 hours (n = 3). These data demonstrate that activated HSC express p75 and respond to NGF stimulation by undergoing apoptosis. We therefore report p75 as a novel marker of activated HSC and suggest that signaling via ligand binding to p75 may provide a mechanism for selective apoptosis of HSC.

Animals↗
PubMed2000

Metabolic response during sport rock climbing and the effects of active versus passive recovery.

The objectives of this study were to 1) continuously assess oxygen uptake during and after difficult sport rock climbing and 2) to evaluate the effects of active versus passive recovery on post-climbing blood lactate and hand grip strength. Fifteen expert rock climbers attempted to climb (i.e., red point lead) a 20 m difficult route (5.12 b, YDS scale) set on an indoor climbing wall. Subjects were assigned to either active recovery (AR; n = 8), consisting of recumbent cycling at 25 Watts, or passive recovery (PR; n = 7). Expired air was analyzed during climbing and through a 10-minute recovery period by a lightweight battery-powered open circuit system. Oxygen uptake (VO2) and heart rate (HR) were measured continuously and averaged over 20-second intervals. These data were expressed as averages over the entire climb (VO2avg and HRavg) and as peak values. An estimated resting VO2 of 250 ml x min(-1) was subtracted from the interval VO2 values to provide net VO2 data which were subsequently converted to absolute VO2 values in liters for climbing (C - VO2net) and recovery (R - VO2net). Total net VO2 was calculated as the sum of C - VO2net plus R - VO2net. Blood samples were obtained via fingerprick at pre-climb and at 1-, 10-, 20-, and 30-minutes post-climb and analyzed for whole blood lactate. Handgrip strength was measured via dynamometry at pre-climb and at 1-, 10-, 20-, and 30-minutes post-climb. Mean climbing time was 2.57 +/- 0.41 min. During climbing, VO2avg and HRavg means were 1660 +/- 340 ml x min(-1) and 148 +/- 16 b x min(-1) respectively with mean peaks of 2147 +/- 413 ml x min(-1) and 162 +/- 17 b x min(-1). Relative VO2avg was 24.7 +/- 4.3 ml x kg(-1) x min(-1) with a mean peak value of 31.9 +/- 5.3 ml x kg(-1) x min(-1). Mean values for C - VO2net and R - VO2net were 4.009 +/- 0.929 L and 2.809 +/- 0.518 L respectively for the PR group with mean total net VO2 at 6.818 +/- 1.291 L. For the AR group mean values for C - VO2net and R - VO2net were 4.216 +/- 1.174 L and 7.691 +/- 3.154 L respectively with a mean total net VO2 of 11.906 +/- 4.172 L. There was no difference between the groups for C - VO2net, however R - VO2net and total net VO2 were significantly different (p < 0.05) between PR and AR. Blood lactate increased significantly with climbing in both AR and PR groups. Lactate remained elevated in the PR group until 30 minutes post-climb, but had returned to pre-climb level by 20 minutes in the AR group. Handgrip strength was significantly decreased at 1-minute post-climb for the AR group, but was not significantly changed for the PR group. Although climbers may be able to attain a plateau in VO2, the observed accumulation of lactate in the blood combined with the elevated recovery VO2 indicate a higher overall energy demand than indicated via the recorded VO2 during climbing. Low intensity active recovery appears to significantly reduce accumulated blood lactate within 20 minutes following difficult climbing, however further research is required to establish whether this strategy is advantageous for subsequent climbing performance.

Adult↗
PubMed2000

A new in vivo and in vitro B cell lymphoma model, pi-BCL1.

We report a new variant of the BCL1 syngeneic mouse B-cell lymphoma model, which we have called pi-BCL1. pi-BCL1 can be established as a syngeneic tumor in BALB/c mice. Tumors can be removed, prepared and easily grown in liquid culture and subsequently transferred back successfully as syngeneic tumors. As a syngeneic tumor pi-BCL1 behave more like a lymphoma with solid tumor masses, than a chronic lymphocytic leukaemia of the original BCL1 model. The immunophenotype and the growth characteristics of the pi-BCL1 and BCL1 tumors appear very similar. Cytologically, pi-BCL1 appears to be a transformation from a small lymphocytic lymphoma to a more diffuse large cell centroblast-like higher-grade lymphoma. We are not aware of any previous reports of such transformation events in a syngeneic animal model of B cell lymphoma. We believe pi-BCL1 provides a useful new tool for the study of B cell lymphoma in vitro and in vivo and enables reduced numbers of tumor passage in mice.

Animals↗
PubMed1999

The effect of wind speed and direction on the distribution of sewage-associated bacteria.

A study of the relationship between wind and the distribution of sewage-associated bacteria was undertaken at a location where the sewage was discharged into the sea adjacent to the mouth of a river. The numbers of presumptive Escherichia coli were determined in 149 sea-water samples taken from three locations at distances of 1.9, 2.4 and 4.3 km from the outfall. On each sampling occasion, data on the wind speed and direction in the 3 h prior to collection of the samples were also collected. Analysis of these data demonstrated a significant role for wind speed and direction. With respect to wind direction, the numbers of presumptive E. coli present in a sample were significantly higher when the sample site lay downwind of the outfall. Wind speed was shown to have an influence on the numbers of presumptive E. coli only when the sample site was downwind of the outfall. In an analysis of 61 samples, an inverse correlation (r2 = 0.73) between salinity and log presumptive E. coli numbers was demonstrated. These data demonstrate that wind speed and direction at the time of sampling significantly influence the numbers of presumptive E. coli detected in any sea-water sample. It is argued that failure to pay sufficient attention to these parameters in the design of monitoring programmes may result in the generation of data that could provide a seriously distorted picture of the microbiological status of a water body.

Colony Count, Microbial↗
PubMed1999

Metabolic and cardiovascular responses during work on a high ropes course.

BACKGROUND: High ropes course facilities are employed in adventure programs to promote self-esteem, stress management, and problem-solving skill development. Although the combination of fear, anxiety, and potentially high levels of physical exertion during such activity could yield situations of cardiac risk for certain individuals, no previous research has described the physiological nature of high ropes course work. The purpose of this study was to observe the metabolic and cardiovascular responses to a typical high ropes course experience. METHODS: Seventeen subjects gave informed consent to complete a 5-element sequence on an indoor high ropes course. The elements included step-swings (SS), swinging tires (ST), a 4-inch balance beam (B1), a vertical cargo net (CN), and a second beam (B2). These elements were positioned in series at a height of 20 feet above the floor. Expired air was analyzed continuously using a portable open circuit metabolic analyzer and heart rate (HR) was recorded at 5-second intervals via telemetry. Pre- and postcourse blood samples were obtained via finger-prick and analyzed for lactate (BL). Systolic (SBP) and diastolic (DBP) blood pressures were taken at an orientation session prior to each subject's test date and at pre-, mid-, and post course points during each test session. RESULTS: The mean ropes course work time was 11.2 +/- 2.9 min. Mean averaged/peak oxygen uptake (VO2), ventilation (VE), HR, and energy expenditure (EE) were 13.9 +/- 2.3/21.6 +/- 3.7 ml.kg-1.min-1, 36.4 +/- 8.1/49.6 +/- 10.3 l.min-1, 142 +/- 16/167 +/- 15 b.min-1, and 5.1 +/- 0.9/7.7 +/- 1.0 kcal.min-1 respectively. In descending order, mean EE was 6.2 +/- 1.1, 6.2 +/- 0.8, 5.4 +/- 1.0, 4.5 +/- 0.5, and 4.2 +/- 0.5 kcal +/- min-1 for the B2, ST, CN, B1, and SS elements respectively. Blood lactate increased (p < 0.05) from a pre course value of 1.9 +/- 0.6 mmol.l-1 to 5.0 +/- 1.1 mmol.l-1 post course. SBP values at pre- (136.7 +/- 16.0), mid-(169.8 +/- 19.7), and postcourse (154.1 +/- 19.2) were higher (p < 0.05) than the orientation SBP of 126.2 +/- 14.7 mmHg. Mid- and post course SBP means were significantly higher than the precourse mean. A significant difference was found for DBP between the midcourse (86.3 +/- 8.9) vs the orientation mean (79.1 +/- 6.8) only. CONCLUSIONS: Based upon the results of this study, average high ropes course work can be classified as aerobically moderate to heavy, at just over 4 METs with peak periods over 7 METs. Transient elevation in DBP may occur during elements with a high level of upper body work. High ropes course work does not present an unusually high physiological stress for healthy, physically fit individuals.

Adult↗
PubMed1998

Radiological appearances of lymphomas arising from mucosa-associated lymphoid tissue (MALT) in the lung.

We review the radiological findings in 13 patients with histologically proven (n = 10) or clinically diagnosed (n = 3) lymphomas arising in mucosa-associated lymphoid tissue (MALT) of the lung. These rare B-cell lymphomas typically follow an indolent course, and many cases are still being incorrectly described in current radiological literature under the term pseudolymphoma. The patients frequently give a history of autoimmune disease involving the affected organ, and involvement of another mucosal site as part of a disseminated MALT lymphoma, is common. The radiographic patterns of pulmonary parenchymal involvement in lung MALT lymphomas have been reviewed, and correlation made with their clinical behaviour.

Adult↗
PubMed1997

Hemorrhagic shock and encephalopathy syndrome. An unusual cause of sudden death in children.

Hemorrhagic shock and encephalopathy syndrome (HSES) is a sudden-onset symptom complex occurring in previously healthy infants and children. It was first described in 1983 in the United Kingdom in 10 infants. Subsequently, > 140 cases have been reported worldwide, although no cases have been previously reported in the forensic literature. Typically the child presents with fever, shock, encephalopathy with coma and seizures, evidence of hemorrhage, and diarrhea. Laboratory investigation reveals falling hemoglobin and platelet counts, renal impairment, evidence of disseminated intravascular coagulation, metabolic acidosis, and raised serum transaminases. Microbiological cultures are uniformly negative. The condition has a high mortality and morbidity. The etiology is unknown and may be multifactorial. However, hyperpyrexia appears to play a central role in pathogenesis. The diagnosis of HSES in the deceased child is one of exclusion and requires a careful antemortem history as well as a thorough autopsy with toxicological and microbiological investigations. A case of HSES is reported and the literature reviewed.

Brain Diseases↗
PubMed1996

Evaluating zona pellucida structure and function using antibodies to rabbit 55 kDa ZP protein expressed in baculovirus expression system.

A cDNA encoding the rabbit 55 kDa ZP protein was expressed using a baculovirus expression system and was evaluated for its ability to elicit antibodies which may interfere with sperm-ZP interaction. The expressed glycosylated protein, BV55, was purified by wheat germ agglutinin lectin affinity chromatography. Antisera made in guinea pigs immunized with BV55 (GP-alpha-BV55) is specific for the 55 kDa rabbit ZP protein. Indirect immunofluorescence studies indicate that GP-alpha-BV55 localizes to a filamentous meshwork on the surface of the ZP of isolated rabbit eggs. Immunohistochemical analysis of rabbit ovaries demonstrated that this antigen is localized within the ZP of primary and more advanced stage ovarian follicles but is not detected in primordial follicles. In addition, the 55 kDa antigen was detected in the granulosa cells of secondary stage follicles but not in the oocyte. GP-alpha-BV55 effectively blocked the binding of rabbit sperm to rabbit eggs in vitro. However, Fab fragments generated from GP-alpha-BV55 failed to block sperm binding, suggesting that the inhibitory effect of GP-alpha-BV55 was due to stearic hindrance rather than specific blocking of a sperm receptor site. Although the Fab fragment did not inhibit sperm binding, additional studies demonstrated that biotinylated BV55 protein bound to rabbit sperm in the acrosomal region in a manner consistent with ligand activity in the sperm-ZP interaction, and that BV55 bound to rabbit sperm in a dose-dependent manner. These studies therefore demonstrate that antibodies against recombinant ZP proteins recognize the native intact ZP and inhibit sperm-ZP interaction. They also provide evidence that the rabbit 55 kDa ZP protein, which is the homolog of the pig ZP3 alpha sperm receptor protein, has sperm receptor activity.

Animals↗
PubMed1996

Molecular biology approaches to evaluate species variation in immunogenicity and antigenicity of zona pellucida proteins.

Immunocontraception using the glycoproteins of the mammalian zona pellucida (ZP) has held great promise because antibodies specific to ZP antigens would inhibit fertility and not be abortive. It has been shown, however, that some ZP proteins will elicit adverse effects since immunization may affect ovarian follicular development. These effects vary among different mammalian species as well as on the source of the ZP immunogen. Therefore, the use of molecular biology has been essential in identifying specific ZP protein(s) that inhibit fertility without altering ovarian follicular development and in defining the relationships of ZP proteins among different species. Use of recombinant ZP proteins has allowed us to begin to dissect antigenic domains of ZP proteins and to evaluate their potential roles in the fertilization process. Recent studies using recombinant rabbit ZP proteins to immunize cynomolgus monkeys (Macaca fascicularis) have shown that the 55 kDa ZP protein will elicit antibodies that inhibit sperm binding while not altering ovarian function, in contrast to immunization with a recombinant truncated protein of the 75 kDa ZP protein which causes ovarian dysgenesis. The rabbit 55 kDa protein is the homologue of the pig ZP3 alpha sperm receptor and the human ZPB protein but is distinct from the mouse ZP3 sperm receptor. Expression of this protein using the baculovirus expression system has further shown that the 55 kDa protein binds to capacitated rabbit spermatozoa over the acrosomal region and induces the acrosome reaction. Antibodies against this recombinant form of the ZP also inhibit rabbit spermatozoa from binding to rabbit egg in vitro. These studies demonstrate the need to determine the structure and function of ZP proteins of different mammalian species to evaluate their potential for contraceptive vaccines.

Animals↗