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Biomedical subjects

G Bell

Publications and source records attributed to G Bell.

At least 55 records · Page 3Linked to original sources

Functional electrical stimulation exercise increases GLUT-1 and GLUT-4 in paralyzed skeletal muscle.

The study purpose was to determine the effect of functional electrical stimulation (FES)-leg cycle ergometer training (30 minutes on 3 d/wk for 8 weeks) on the GLUT-1 and GLUT-4 content of paralyzed skeletal muscle. Biopsy samples of vastus lateralis muscle were obtained pre- and post-training from five individuals with motor-complete spinal cord injury ([SCI] four men and one woman aged 31 to 50 years, 3 to 25 years postinjury involving C5-T8). Western blot analysis indicated that GLUT-1 increased by 52% and GLUT-4 increased by 72% with training (P < .05). This coincided with an increase in the muscle oxidative capacity as indicated by a 56% increase in citrate synthase (CS) activity (P < .05) and an improvement in the insulin sensitivity index as determined from oral glucose tolerance tests (P < .05). It is concluded that FES endurance training is effective to increase glucose transporter protein levels in paralyzed skeletal muscle of individuals with SCI.

Adult↗

Histochemical changes in muscle of individuals with spinal cord injury following functional electrical stimulated exercise training.

STUDY DESIGN: Longitudinal training. OBJECTIVES: To determine the effects of functional electrical stimulated (FES) leg cycle ergometer training on muscle histochemical characteristics in individuals with motor-complete spinal cord injury (SCI). SETTING: University of Alberta, Edmonton, Alberta, Canada. METHODS: Six individuals with motor-complete SCI (age 31-50 years; 3-25 years post-injury) trained using FES leg cycle ergometry for 30 min, 3 days per week for 8 weeks. Biopsies of the vastus lateralis muscle were obtained pre- and post-training and analyzed for fibre composition, fibre size and capillarization. RESULTS: The majority of muscle fibres were classified as type 2 pre- and post-training. Average fibre area increased 23% (P<0.05) and capillary number increased 39% (P<0.05) with training. As a result of these proportional increases, capillarization expressed relative to fibre area was unchanged with training. CONCLUSIONS: FES leg cycle ergometer training results in proportional increases in fibre area and capillary number in individuals with SCI.

Adult↗

Massive bleeding during spine surgery in a patient with ankylosing spondylitis.

PURPOSE: Ankylosing spondylitis is associated with pathophysiology that has important anaesthetic implications. We report a case where the sequelae of ankylosing spondylitis may have been responsible for massive bleeding during emergency spine surgery. CLINICAL FEATURES: A 69 yr old man with long standing ankylosing spondylitis sustained a complex fracture of the lumbar spine in a fall, and was scheduled for stabilization of the spine. Under general anaesthesia, prone positioning was difficult because of the extreme spinal deformity. During exploration, dilatation of epidural veins was encountered and sustained haemorrhage was encountered throughout the surgical procedure. Estimated blood loss was 17,000 ml which was replaced with 31 units of packed red blood cells, 3200 ml of salvaged blood, 18 units of fresh frozen plasma, 26 units of platelets, 1,000 ml of albumin and 9,000 ml of crystalloid. CONCLUSIONS: Extreme deformity of the spine led to positioning difficulties that may have contributed to massive blood loss during complex spine surgery. Difficulties with placement in the prone position in-patients with advanced ankylosing spondylitis should be anticipated.

Aged↗

Sexual networks: the integration of social and genetic data.

New methods for studying sexual networks are presented, drawing upon routine procedures followed in genitourinary medicine clinics in the UK for tracing partners and identifying strains of infection. The routine social procedures were developed to incorporate a structured interview. The routine microbiological diagnosis of gonorrhoea was augmented by phenotyping and the development of new genetic techniques for the fine discrimination of gonococcal strains (opa-typing). Selected results from a study in Sheffield, UK show that each method has limitations, when conducted separately, but these are minimised when the methods are combined. Moreover, the use of simple and routine methods of data collection resolve issues of scale and sample that have beset other network studies, as they provide a means of covering a larger and defined population. Popular concepts about these methods are discussed in the conclusion. The integrated approach employed in our research raises questions both about social methods, 'of people who lie, particularly when they talk about sex', and about microbiological methods, 'of genes that tell the truth' and bypass what people say and think altogether. We argue that these stereotypes are misleading insofar as they suggest that genetic techniques can substitute for the social, and we suggest that even the finest discrimination of organisms at the genetic level will never obviate the need for their interpretation in the light of social data.

Adult↗

The effect of a needle biopsy of the vastus lateralis on isokinetic muscular performance.

OBJECTIVE: To determine the acute effects of a needle muscle biopsy of the vastus lateralis on knee extension and flexion strength and endurance. DESIGN: Pretest-posttest design. Testing order of right or left leg was randomly determined. SETTING: Research Laboratory, University of Alberta, Edmonton Alberta, Canada. PARTICIPANTS: The subjects were 8 female and 11 male volunteers who were recreationally active. The mean age, height, and weight were 23 +/- 5 years, 174.6 +/- 9.2 cm, and 73.5 +/- 7.3 kg, respectively. INTERVENTION: Isokinetic testing for knee extension and flexion was performed on both legs before and after a biopsy of the right vastus lateralis muscle. MAIN OUTCOME MEASURES: Knee extension and flexion peak torque measured at an angular velocity of 1.05 rad.s-1. Mean torque during 25 consecutive maximal contractions at 3.14 rad.s-1 for knee extension and flexion exercise. RESULTS: There was a significant decrease in right knee extension peak torque after the biopsy of the vastus lateralis muscle. No other differences were noted. CONCLUSIONS: These findings demonstrated an acute inhibition of knee extension peak torque but not endurance because of a muscle biopsy of the involved musculature.

Adult↗

Partner notification for gonorrhoea: a comparative study with a provincial and a metropolitan UK clinic.

OBJECTIVE: To compare partner notification practice and outcomes at a provincial and a metropolitan clinic. DESIGN: Prospective study, following standardisation of partner notification policy. SETTINGS: Sheffield Department of Genitourinary Medicine, Royal Hallamshire Hospital and Jefferiss Wing Centre for Sexual Health, St Mary's Hospital, London. SUBJECTS: Consecutive patients with culture positive gonorrhoea between October 1994 and March 1996 who were interviewed by a health adviser. RESULTS: In Sheffield, 235 cases reported 659 outstanding contacts, of whom 129 (20%) were subsequently screened, and 65 (50%) had gonorrhoea. At St Mary's 510 cases reported 2176 outstanding contacts, of whom 98 (5%) were known to have been screened, and 53 (54%) had gonorrhoea. Patient or provider referral agreements appeared more productive in Sheffield, where 60% resulted in contact attendance, compared with 13% at St Mary's. Provider referral was used more frequently in Sheffield, for 44% of referrals, compared with 1% at St Mary's. Multivariate analysis showed that partner notification was less effective for casual and short term (< 7 days) partnerships in both centres, and for homosexual men at St Mary's. CONCLUSION: Partner notification outcomes were better in the provincial setting where contact attendance could be recorded more reliably and provider referral was used more extensively. The high proportion of contacts who remained untraced in both settings indicates the need for complementary screening and prevention initiatives.

Adult↗

Sexual histories, partnerships and networks associated with the transmission of gonorrhoea.

We aimed to describe and compare sexual links among people with gonorrhoea, by studying patients in 2 UK departments of genitourinary medicine. Interviews were completed for 510 and 235 cases in London and Sheffield respectively. There was a greater proportion of cases in men, homosexual men, non-white and non-British people and fewer female sex workers in London. Total networks of 1738 people in London and 570 people in Sheffield were described. Large linked heterosexual networks identified in Sheffield were associated with local contact, including men with higher numbers of sexual partners. Condom use for vaginal sex was reported for 11% of heterosexual partnerships in Sheffield, and 27% in London, with little difference between regular and casual partners. It was more difficult to define networks in London due to a high proportion of relatively anonymous contacts. These difficulties suggest that research and interventions may profitably focus upon venues for meeting partners as well as partner notification.

Adolescent↗

Effects of combined endurance and strength training on left ventricular morphology in male and female rowers.

The effects of 10 weeks of combined endurance and strength training on left ventricular (LV) morphology, muscular strength, maximal oxygen consumption (VO2max) and rowing performance were assessed. Twenty-five subjects (eight males, mean age 23.0 +/- 6.1 years, and 17 females, 22.7 +/- 5.0 years) were tested at baseline and after five and 10 weeks of training. Combined training was associated with significant improvements in VO2max, rowing performance and muscular strength after 10 weeks of training. A significant increase in LV diastolic dimension was found in males after 10 weeks of training; however, no significant alteration was found for any other measured echocardiographic variable. Therefore, with the exception of LV diastolic dimension in males, 10 weeks of combined endurance and strength training appears to be an insufficient stimulus to elicit significant alterations in LV morphology despite changes in VO2max, muscular strength or rowing performance.

Female↗

The advantage of sex in evolving yeast populations.

Sex is a general feature of the life cycle of eukaryotes. It is not universal, however, as many organisms seem to lack sex entirely. The widespread occurrence of sex is puzzling, both because meiotic recombination can disrupt co-adapted combinations of genes, and because it halves the potential rate of reproduction in organisms with strongly differentiated male and female gametes. Most attempts to explain the maintenance of sexuality invoke differences between parents and sexual offspring. These differences may be advantageous in novel or changing environments if new gene combinations are favoured from time to time. Sex would then serve to concentrate beneficial mutations that have arisen independently into the same line of descent. But in a stable environment sex might serve to concentrate deleterious mutations, so that they will be more effectively purged from the population by selection. We have studied the effect of sex on mean fitness in experimental populations of the budding yeast Saccharomyces cerevisiae. Our results show that sex increases mean fitness in an environment to which the populations were well adapted, but not in an environment to which new adaptation occurred, supporting the hypothesis that the advantage of sexuality lay in the removal of deleterious mutations.

Adaptation, Physiological↗

Activation of human somatostatin receptor type 2 causes inhibition of cell growth in transfected HEK293 but not in transfected CHO cells.

Somatostatin (SS) is known to have an antiproliferative effect on cell growth via somatostatin receptors (SSTR). The purpose of this study was to transfect cell lines with human SSTR2 and determine the subsequent effect on cell growth in response to SSTR agonist. Heterologous Chinese hamster ovary (CHO-K1) and human embryonic kidney 293 (HEK) cells were transfected with SSTR2 cDNA using lipofectin. Stable transformants were selected by G418 and confirmed by 125I-SS binding and RT-PCR. Binding studies were performed in the presence of 10(-6) to 10(-12) M SS-14, SS-28, SS analogue RC-160, SSTR2 agonist NC-9-74, and SSTR5 agonist DC-37-39. Cell growth was determined by counting cell numbers after 48 hr incubation in the presence of 10(-6) to 10(-12) M SSTR2 agonist NC-9-74. Binding of 125I-SS-14 to transfected CHO and transfected HEK293 cells showed that the cells had high affinity for SS-14, SS-28, NC-9-74, and RC-160 but low affinity for DC-37-39. Incubation with 10(-6) to 10(-12) M NC-9-74, showed that 1 nM to 1 microM NC-9-74 significantly inhibited transfected HEK293 cell growth but did not affect growth on transfected CHO cells (n = 4 for each dose, P < 0.01). The two cell lines transfected with the human SSTR2 showed similar high affinity for SS-14, SS-28, RC-160, and SSTR2 agonist but not SSTR5 agonist. The SSTR2 agonist NC-9-74 significantly inhibited transfected HEK293 cell growth but not CHO cells. These data suggest that activation of SSTR2 was more efficiently coupled to the signal transduction pathway of antiproliferation in the transfected HEK293 cells.

Animals↗

Skeletal muscle fibre type transformation following spinal cord injury.

Following spinal cord injury (SCI), upper motor neuron paralysed muscles lose the normal type I (slow) and II (fast) fibre mosaic pattern and become predominantly composed of type II (fast glycolytic) fibres). The majority of the research demonstrating this fibre type shift was based on pH sensitive myofibrillar ATPase staining techniques on muscle from longstanding paraplegics and quadriplegics. The purpose of this study was to describe muscle fibre type changes over a wide time spectrum post SCI using immunofluorescent techniques which may be more sensitive to change. A total of 19 vastus lateralis muscle biopsy specimens were obtained from 12 SCI subjects representing time points of 0.5-219 months post SCI. Fast and slow myosin heavy chain isoform distribution was determined on single muscle fibres for each of the biopsy specimens. Early post SCI (< 1 month) myosin heavy chain (MCH) isoform composition remained relatively stable. A transitional period was seen between 1 and 20 months post SCI wherein there was a progressive drop in the proportion of slow MHC isoform fibres and a rise in the proportion that co-expressed both the fast and slow MHC isoform. By approximately 70 months post SCI a new steady state had been reached characterized by almost exclusively fast MHC isoform expression. This research has demonstrated that post SCI muscle type II transformation occurs in stages and commences earlier than previously appreciated. Interventions aimed at preventing or minimizing the transformation would need to be instituted within weeks post SCI.

Adenosine Triphosphatases↗

Interaction between cortisol and tumour necrosis factor with concurrent resistance and endurance training.

OBJECTIVE: To determine the effect of concurrent resistance and endurance training on tumor necrosis factor alpha (TNF alpha), urinary free cortisol, strength [one-repetition maximum (1 RM)], and maximal oxygen consumption (Vo2max). DESIGN: Randomized control trial of 12 weeks' duration. SETTING: University of Alberta, Edmonton, Alberta, Canada. PARTICIPANTS: Forty-five healthy female (n = 18) and male (n = 27) subjects who had not formally trained for at least 6 months prior to the study but were physically active. The mean +/- SD age, height, and body mass for all subjects were 22.3 +/- 3.3 years, 1.76 +/- 9.32 m, and 73.4 +/- 11.6 kg, respectively. INTERVENTION: The subjects were randomly assigned to four groups: strength training only (S), n = 10; endurance training only (E), n = 11; combined strength and endurance training (SE), n = 13; and a control group (C), n = 10. The S and E groups performed progressively overloaded training sessions three times per week for 12 weeks. The SE group completed the same strength and endurance training programs on different days (i.e., 6 days/week) for 12 weeks. MAIN OUTCOME MEASURES: Serum levels of TNF alpha, urinary free cortisol, 1 RM, and Vo2max were measured before and after 6 and 12 weeks of training. RESULTS: Significant increases in leg press and knee extension 1 RM occurred after training in both S and SE groups, but the relative gains in knee extension 1 RM were greater in the S group. Similar increases in Vo2max were observed in groups E and SE (p < 0.05). Cortisol was significantly increased in the SE group for women and decreased in the E group for men after training. TNF alpha was significantly elevated in the women of group E after training. No correlation was observed between urinary free cortisol and TNF alpha with training. CONCLUSION: These results indicate that a partial interference effect of compromised strength gains in unilateral knee extension of the men occurred after concurrent strength and endurance training that could not be attributed to an interaction between cortisol and TNF alpha in response to this type of exercise.

Adult↗

Incidence and nature of bile duct injuries following laparoscopic cholecystectomy: an audit of 5913 cases. West of Scotland Laparoscopic Cholecystectomy Audit Group.

The rapid introduction of laparoscopic cholecystectomy has been associated with an apparently increased incidence of bile duct injury which has provoked worldwide concern. The true incidence and mechanism of iatrogenic ductal injury during the development of this procedure remain unclear. To assess this, the introduction of laparoscopic cholecystectomy in the West of Scotland has been audited prospectively over a 5-year period. All cases of biliary ductal injury have been independently reviewed. Some 48 surgeons undertaking laparoscopic cholecystectomy in 19 hospitals submitted prospective data between September 1990 and September 1995. A total of 5913 laparoscopic cholecystectomies were attempted with 98.3 per cent completion of data collection. During this period 37 laparoscopic bile duct injuries occurred. The annual incidence peaked at 0.8 per cent and has fallen to 0.4 per cent in the final year of audit. Injuries occurred after a median personal experience of 51 (range 3-247) laparoscopic cholecystectomies in 22 surgeons. Major bile duct injuries occurred in 20 of 37 patients, giving an incidence of 0.3 per cent. Five mechanisms for laparoscopic ductal injury were identified, including tenting, confluence and diathermy injuries as well as the classical and variant classical types. Ductal injuries were discovered at operation in 18 patients with consequent repair giving a good clinical outcome in 17. Contributory factors (severe inflammation, aberrant anatomy and poor visualization) were present in only 13 of 37 cases. This audit suggests that, at least in the introductory period, laparoscopic cholecystectomy is associated with an overall bile duct injury rate higher than that reported previously after open cholecystectomy, although the incidence of major ductal injury is similar. The late downward trend in bile duct injury, however, suggests there may be a prolonged learning curve for this procedure. Improved understanding of the mechanism of injury may lead to yet further reductions in this complication.

Bile Ducts↗

Sex and the spread of retrotransposon Ty3 in experimental populations of Saccharomyces cerevisiae.

Mobile genetic elements may be molecular parasites that reduce the fitness of individuals that bear them by causing predominantly deleterious mutations, but increase in frequency when rare because transposition increases their rates of transmission to the progeny of crosses between infected and uninfected individuals. If this is true, then the initial spread of a mobile element requires sex. We tested this prediction using the yeast retrotransposon Ty3 and a strain of Saccharomyces cerevisiae lacking Ty3. We infected replicate isogenic sexual and asexual populations with a galactose-inducible Ty3 element at an initial frequency of 1%. In two of six asexual populations, active Ty3 elements increased in frequency to 38 and 86%, due to the spread in each population of a competitively superior mutant carrying a new Ty3 insertion. Ty3 frequencies increased above 80% in all sexual populations in which transposition was induced in haplophase or in diplophase. Ty3 did not increase in frequency when active during both haplophase and diplophase, apparently because of selective sweeps during adaptation to galactose. Repressed Ty3 elements spread in sexual populations, by increasing sexual fitness. These results indicate that active Ty3 elements are more likely to become established in sexual populations than in asexual populations.

Crosses, Genetic↗