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Biomedical subjects

L Bruce

Publications and source records attributed to L Bruce.

At least 19 recordsLinked to original sources
PubMed2005

The development of a test of reactive agility for netball: a new methodology.

The purpose of this study was to present a new methodology for the measurement of agility for netball that is considered more ecologically valid than previous agility tests. Specifically, the agility performance of highly-skilled (n = 12), moderately-skilled (n = 12) and lesser-skilled players (n = 8) when responding to a life-size, interactive video display of a netball player initiating a pass was compared to a traditional, pre-planned agility movement where no external stimulus was present. The total movement times and decision times of the players were the primary dependent measures of interest. A second purpose of the research was to determine the test-retest reliability of the testing approach. Results revealed significant differences existed between the 2 test conditions demonstrating that they were measuring different types of agility. The highly-skilled group was significantly faster in both the reactive and planned test conditions relative to the lesser-skilled group, while the moderately-skilled group was significantly faster than the lesser-skilled group in the reactive test condition. The decision time component within the reactive test condition revealed that the highly-skilled players made significantly faster decisions than the lesser-skilled players. It is reasoned that it is this decision-making component of reactive agility that contributes to the significant differences between the two test conditions. The testing approach was shown to have good test-retest reliability with an intra-class correlation of r = .83.

Adolescent↗
PubMed2004

Acute effects of static stretching on hip flexor and quadriceps flexibility, range of motion and foot speed in kicking a football.

The purpose of this research was to determine the effect of static stretching in a warm-up on hip flexor and quadriceps flexibility as measured by a modified Thomas test and on range of motion (ROM) of the leg and foot speed at impact in kicking a football with maximum effort. Sixteen Australian Rules (AR) footballers performed two different warm-ups on different days. One warm-up involved five minutes of sub-maximum running followed by seven practice kicks, while the other also included 4.5 minutes static stretching of the hip flexors and quadriceps after the running. A modified Thomas test was conduced before and after each warm-up. Players performed maximum effort drop punt kicks into a net while being videotaped to determine the ROM of the kicking leg and foot speed at impact with the ball. There were no significant changes in flexibility (p > 0.05) as a result of either warm-up and there were no significant differences between the warm-ups in the kicking variables (p > 0.05). It was concluded that the Thomas test may not have been sensitive to possible acute changes in flexibility from the warm-ups, and that stretching had no influence on kicking ROM or foot speed, possibly because of the complexity of the kicking skill.

Adolescent↗
PubMed2001

Overexpression of FK506-binding protein FKBP12.6 in cardiomyocytes reduces ryanodine receptor-mediated Ca(2+) leak from the sarcoplasmic reticulum and increases contractility.

The FK506-binding protein FKBP12.6 is tightly associated with the cardiac sarcoplasmic reticulum (SR) Ca(2+)-release channel (ryanodine receptor type 2 [RyR2]), but the physiological function of FKBP12.6 is unclear. We used adenovirus (Ad)-mediated gene transfer to overexpress FKBP12.6 in adult rabbit cardiomyocytes. Western immunoblot and reverse transcriptase-polymerase chain reaction analysis revealed specific overexpression of FKBP12.6, with unchanged expression of endogenous FKBP12. FKBP12.6-transfected myocytes displayed a significantly higher (21%) fractional shortening (FS) at 48 hours after transfection compared with Ad-GFP-infected control cells (4.8+/-0.2% FS versus 4+/-0.2% FS, respectively; n=79 each; P:=0.001). SR-Ca(2+) uptake rates were monitored in beta-escin-permeabilized myocytes using Fura-2. Ad-FKBP12.6-infected cells showed a statistically significant higher rate of Ca(2+) uptake of 0.8+/-0.09 nmol/s(-)(1)/10(6) cells (n=8, P:<0.05) compared with 0.52+/-0.1 nmol/s(-)(1)/10(6) cells in sham-infected cells (n=8) at a [Ca(2+)] of 1 micromol/L. In the presence of 5 micromol/L ruthenium red to block Ca(2+) efflux via RyR2, SR-Ca(2+) uptake rates were not significantly different between groups. From these measurements, we calculate that SR-Ca(2+) leak through RyR2 is reduced by 53% in FKBP12.6-overexpressing cells. Caffeine-induced contractures were significantly larger in Ad-FKBP12.6-infected myocytes compared with Ad-GFP-infected control cells, indicating a higher SR-Ca(2+) load. Taken together, these data suggest that FKBP12.6 stabilizes the closed conformation state of RyR2. This may reduce diastolic SR-Ca(2+) leak and consequently increase SR-Ca(2+) release and myocyte shortening.

Adenoviridae↗
PubMed2000

P(i) inhibits the SR Ca(2+) pump and stimulates pump-mediated Ca(2+) leak in rabbit cardiac myocytes.

Measurements of sarcoplasmic reticulum (SR) Ca(2+) uptake were made from aliquots of dissociated permeabilized ventricular myocytes using fura 2. Equilibration with 10 mM oxalate ensured a reproducible exponential decline of [Ca(2+)] from 600 nM to a steady state of 100-200 nM after addition of Ca(2+). In the presence of 5 microM ruthenium red, which blocks the ryanodine receptor, the time course of the decline of [Ca(2+)] can be modeled by a Ca(2+)-dependent uptake process and a fixed Ca(2+) leak. Partial inhibition of the Ca(2+) pump with 1 microM cyclopiazonic acid or 50 nM thapsigargin reduced the time constant for Ca(2+) uptake but did not affect the SR Ca(2+) leak. Addition of 10 mM inorganic phosphate (P(i)) decreased the rate of Ca(2+) accumulation by the SR and increased the Ca(2+) leak rate. This effect was reversed on addition of 10 mM phosphocreatine. 10 mM P(i) had no effect on Ca(2+) leak from the SR after complete inhibition of the Ca(2+) pump. In conclusion, P(i) decreases the Ca(2+) uptake capacity of cardiac SR via a decrease in pump rate and an increase in Ca(2+) pump-dependent Ca(2+) leak.

Animals↗
PubMed1997

Increased sensitization of the myofilaments in rat neonatal portal vein: a potential mechanism.

The contractile regulation of neonatal smooth muscle was studied in rat neonatal portal vein. Strips of beta-escin-permeabilized portal vein from 3- to 5-day-old rats and 5- to 6-week-old rats were mounted on a 'bubble chamber' in calcium solutions buffered with 10 mM EGTA. Although the overall tension development was lower in neonatal muscle as expected, the calcium sensitivity of the neonatal permeabilized portal vein was significantly higher than in developed portal vein. Endothelin-1-induced sensitization of the myofilaments was investigated. Endothelin-1 produced an increase in tension of permeabilized neonatal portal vein in a calcium solution buffered with 10 mM EGTA. This sensitization was proportionally higher in neonatal than in developed smooth muscle, despite similar initial submaximal calcium contractions. GTP gamma S-induced calcium sensitization was also proportionally higher in neonatal permeabilized strips than in fully developed smooth muscle. These changes may be due to alterations in the intracellular signalling pathways which mediate calcium sensitization in smooth muscle. As some endothelin-1-mediated responses are known to occur via activation of the heterotrimeric GTP-binding protein, Gq, the levels of protein expression of Gq alpha were studied. In membrane preparations from neonatal rat portal vein the expression of Gq alpha was significantly higher than in portal vein membrane preparations loaded with equal protein from 5- to 6-week-old rats. In conclusion, agonist-induced sensitization of the myofilaments was higher in neonatal rat portal vein than in fully developed portal vein. This difference is the result of changes in intracellular signalling and may be partly produced by the greater expression of Gq alpha observed in neonatal portal vein.

Actin Cytoskeleton↗
PubMed1992

Treatment of malignant melanoma and renal cell carcinoma with recombinant human interleukin-2: analysis of cytokine levels in sera and culture supernatants.

In this study we evaluated the clinical response of 12 patients with malignant melanoma and renal cell carcinoma (RCC) following administration of recombinant human interleukin-2 (rhIL-2) by continuous infusion. Serum samples taken before, during and following sequential courses of IL-2 were assayed for the presence of tumour necrosis factor alpha (TNF-alpha) IL-1 alpha, IL-6 and interferon gamma (IFN-gamma) and the presence or changes in these cytokines were examined with respect to clinical response data: our results did not show any direct correlation between the parameters measured and clinical outcome. In addition, peripheral blood mononuclear cells (PBMC) derived from 3 RCC patients were cultured in a serum-free environment and the resulting supernatants assayed for the production of these cytokines and compared to the corresponding serum levels. During one or more courses of treatment only 1 patient, who had metastatic bone disease, demonstrated detectable serum TNF-alpha; serum IL-6 levels were elevated in a proportion of all patients studied and a sustained IL-6 response occurred in a patient who had complete disease remission; IL-1 alpha was detected in the serum of 3 RCC patients; IFN-gamma could not be detected in any serum sample tested. Cytokine levels in sera and supernatants derived from 3 RCC patients were compared but no correlation was found: TNF-alpha and IL-6 were shown to be present at much higher concentrations in supernatants when compared to sera whereas the levels of IL-1 alpha were almost undetectable. This lack of correlation is probably due to the presence of "interfering" proteins in sera which either depress or enhance the ability to detect cytokines in sera using enzyme immunoassays.

Carcinoma, Renal Cell↗
PubMed1991

Malignant melanoma and renal cell carcinoma: immunological and haematological effects of recombinant human interleukin-2.

The immunological and haematological effects of continuous infusion of recombinant human interleukin-2 (rhIL-2) in 6 patients with metastatic melanoma and 6 with disseminated renal cell carcinoma are reported. In patients with malignant melanoma dacarbazine was given before IL-2; in renal cell carcinoma IL-2 alone was given. In malignant melanoma, 1 complete (CR) and 1 partial response (PR) were seen; 2 patients had stable disease (SD) and 2 progressive disease (PD). In renal cell carcinoma 4 patients had SD and 2 PD. Toxicity of IL-2 therapy was minimal. All patients showed increased cytotoxicity, that was not major histocompatibility complex restricted, towards target cells sensitive and insensitive to natural killer cells. These activities varied between individual patients and were less marked in cases of renal cell carcinoma. Cellular proliferative responses increased in all patients, being consistently higher following the first course of therapy, as did HLA-DR, CD16 and CD25 activation marker expression. Hypersegmentation of neutrophils and eosinophilia were commonly observed, and in renal cell carcinoma these changes were accompanied by abnormal lymphocyte morphology.

Aged↗
PubMed1989

[Variations in arch and tooth size in the upper jaw of cleft palate patients].

The size of the upper dental arch and of the upper permanent teeth in a group of cleft lip/palate patients of both sexes, 12 years of age and older were compared to a control group of normal patients. Our results showed a significant size reduction in all of the longitudinal arch dimensions in cleft lip/palate patients. It was also seen a significant reduction of the intercanine and intermolar width dimensions. Mesiodistal and buccolingual teeth diameter reductions were observed in patients with left unilateral cleft lip and cleft palate, being this feature remarkable in the central and lateral incisors. Differences in size between antimeric teeth were only observed in upper lateral incisors in patients with left unilateral clefts. The relative influence of genetic and environmental factors on our patients was not determined with the results obtained in the present investigation.

Adolescent↗
PubMed1989

Nutrition intervention program in a prenatal clinic.

Pregnant women who are underweight for height and gestational age are at risk of delivering infants weighing less than infants born to women of standard weight. This study demonstrated that a nutrition intervention program geared toward these high-risk women improved infant outcome. A group of 57 underweight and failure-to-gain pregnant women (treated) who received extensive nutrition counseling and follow-up from a nutritionist throughout their pregnancy was compared with a similar group of 52 underweight pregnant women (control) who received no counseling. Women in the treated group gained significantly more weight during their pregnancy than did controls. The treated women also delivered infants who averaged 300 g heavier than those born to the control group, a statistically significant difference. Other factors reported to compromise infant outcome such as ethnic background, income status, age, and smoking did not significantly affect infant birth weight.

Birth Weight↗
PubMed1988

Transfer factor in Hodgkin's disease: a randomized clinical and immunological study.

Transfer factor (TF) was prepared from buffy coats obtained from 493 units of blood taken from healthy donors, including individuals convalescent from various viral infections. It was administered to 22 of 47 patients with Hodgkin's disease undergoing treatment and consenting to take part in this randomized study to determine if TF would enhance their immunity and/or reduce the incidence of subsequent infections. Skin test reactivity was markedly enhanced in those patients receiving TF as opposed to placebo but other immunological assessments showed no significant differences between the groups. TF was not shown to be of benefit in the prevention of infections (including varicella/zoster).

B-Lymphocytes↗
PubMed1987

Risks and benefits of elective hip replacement in the octogenarian.

We reviewed the records for 100 consecutive cases of elective hip replacement in 91 patients in their 80s (average age 82.8 years), all of whom lived in their own homes before surgery. In 92 cases the patients returned home, 59 within 3 weeks. The average duration of hospital stay was 20.1 days. In eight cases there were major complications, including three cases of myocardial infarction (one of them fatal) and two cases of pulmonary embolism (one of them fatal). In 15 cases there were moderate complications, including deep venous thrombosis (in 5) and urinary tract complications necessitating transurethral prostatectomy (in 2). In 44 cases there were minor complications, including the need for urinary catheterization (in 27) and brief periods of postoperative confusion (in 14). In 33 cases there were no complications; in 31 of these cases the patients returned directly home within 3 weeks. The preoperative risk rating of the American Society of Anesthesiologists (ASA) correlated well with the complication rates: the rates of major complications in cases with a rating of ASA class I, II or III were 0%, 6% and 15% respectively. In 49 of 52 cases in which the procedure had been performed more than 2 years previously, the patients were happy they had had the operation.

Aged↗
PubMed1987

Malignant lymphoma: monitoring of tumour status in 273 patients using a monoclonal antibody, 'B5', reacting with autologous erythrocytes.

The value of the B5 antigen haemagglutination test has been assessed in 273 patients with malignant lymphoma--141 with non-Hodgkin's lymphoma (NHL) and 132 with Hodgkin's disease (HD). Of those patients who were in remission after treatment, 41/155 (26%) showed B5 positivity: this compares to an incidence of 20% (122/551) in a wide range of non-tumour bearing individuals. In contrast, those patients with persistent disease, or in relapse, showed a much higher incidence of B5 positivity (84%; 99/118). Serial monitoring of 113 patients showed that B5 status often changed as tumour status changed, becoming more negative with remission, and more positive in relapse. Use of the B5 test in conjunction with erythrocyte sedimentation rate (ESR) gave an increased specificity for active disease in that 87% (35/40) of those who were B5-positive together with a raised ESR had active disease: of those patients who were both B5-negative and had normal ESR, 9 out of 108 (8%) had active disease. These findings suggest a role for the B5 test, combined with the ESR, in the monitoring of patients with malignant lymphoma.

Antibodies, Monoclonal↗
PubMed1987

Nutritional anthropometry and dietary intake of children from the Las Cuevas region of the Dominican Republic.

A nutritional survey was conducted in the "Las Cuevas" watershed located in the southwestern region of the Dominican Republic to assess the nutritional status of preschool children. Height, weight, mid-arm circumference and triceps skinfold measurements were taken of 280 children between 6 to 54 months of age. Dietary recall was elicited from mothers or care givers. Results compared with the National Center for Health Statistics reference data indicate that these children: 1) experience growth failure and poor nutritional status as indicated by low weight for age; 2) suffer chronic malnutrition as revealed by low height for age and reduced muscle mass of the mid-arm; and 3) have appropriate weight for height measurements. A food frequency survey revealed that these children consume a diet high in carbohydrates and low in animal protein. Breast feeding is a common practice although cow's milk was introduced early in 25% of the sample. The mean age at weaning is 12 months. The results indicate that these children experience the greatest growth deficits in the second year of life and that these deficits are indicative of chronic undernutrition rather than acute food shortage or recent disease episodes. This study was carried out to establish baseline data for a resource management project initiated by the Secretariat of Agriculture of the Dominican Republic.

Anthropometry↗