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Biomedical subjects

I MacLean

Publications and source records attributed to I MacLean.

18 recordsLinked to original sources
PubMed2006

Possible reasons for an increase in the proportion of genital ulcers due to herpes simplex virus from a cohort of female bar workers in Tanzania.

OBJECTIVES: To determine trends in the prevalence and aetiological distribution of genital ulcer syndrome (GUS) in a cohort of female bar workers and to assess factors associated with these trends. METHODS: An open cohort of 600 women at high risk of HIV and sexually transmitted infection (STI) was offered screening and treatment for STI at 3-month intervals. The prevalence of GUS and associated aetiological agents (Herpes simplex virus (HSV), Treponema pallidum and Haemophilus ducreyi) were monitored over 27 months through clinical examination, dry lesion swabbing and multiplex polymerase chain reaction. The effects of HIV status and other factors on the prevalence trends of STI were assessed. RESULTS: A total of 753 women were recruited into the cohort over 10 examination rounds. At recruitment, the seroprevalence was 67% for HIV and 89% for HSV type 2 (HSV-2). During follow-up, 57% of ulcers had unknown aetiology, 37% were due to genital herpes and 6% to bacterial aetiologies, which disappeared completely in later rounds. The absolute prevalence of genital herpes remained stable at around 2%. The proportion of GUS caused by HSV increased from 22% to 58%, whereas bacterial causes declined. These trends were observed in both HIV-negative and HIV-positive women. CONCLUSIONS: The changes observed in the frequency and proportional distribution of GUS aetiologies suggest that regular STI screening and treatment over an extended period can effectively reduce bacterial STI and should therefore be sustained. However, in populations with a high prevalence of HSV-2, there remains a considerable burden of genital herpes, which soon becomes the predominant cause of GUS. Given the observed associations between genital herpes and HIV transmission, high priority should be given to the evaluation of potential interventions to control HSV-2 either through a vaccine or through episodic or suppressive antiviral therapy and primary prevention.

Adult↗
PubMed2005

The effect of limited overfeeding during growth on muscle characteristics: a pig model.

Energy restriction affects the hypothalamus, leading to a decrease in production of reproductive and thyroid hormones. A decrease in reproductive hormones affects fertility and a decrease in thyroid hormones affects muscle metabolism. A pig model has been used to determine that reproductive function is negatively affected if the normal practice of overfeeding is limited during the late luteal phase of the estrous cycle. We used a sub-set of pigs from this study to examine effects of limiting overfeeding on thyroid hormones and skeletal muscle (i.e. maximal enzyme activities, and muscle fibre characteristics). Eighteen rapidly growing gilts were randomized into three groups: 1) feeding a high plane of nutrition throughout the first 15 days of the estrous cycle; 2) limited overfeeding (25% below the first group) for first 7 days of the estrous cycle (early luteal phase), followed by a high plane of nutrition for days 8-15 (late luteal phase); and 3) high plane of nutrition throughout the first 7 days of the estrous cycle, followed by 8 days of limited overfeeding. Muscle biopsies were collected from the triceps brachii, and blood samples were collected for assessment of thyroid hormones at days 0 (baseline), 8 and 16. There was no effect of limited overfeeding on thyroid hormones, maximal enzyme activities, muscle fibre area or muscle fibre type. Limited overfeeding in rapidly growing pigs does not affect thyroid hormone status or muscle characteristics.

Animal Feed↗
PubMed2003

Sequence variation in the bovine and ovine PRNP genes.

A resequencing approach was adopted to identify sequence variants in the PRNP gene that may affect susceptibility or resistance to bovine spongiform encephalopathy. The entire PRNP gene (>21 kb) was sequenced from 26 chromosomes from a group of Holstein-Friesian cows, as well as exon 3 of PRNP (>4 kb) from a further 24 chromosomes from six diverse breeds. We identified 51 variant sequences of which 42 were single nucleotide polymorphisms and nine were insertion/deletion (indel) events. The study was extended to exon 3 of the sheep PRNP gene where 23 sequence variants were observed, four of which were indels. The level of nucleotide diversity in the complete bovine PRNP gene was pi = 0.00079, which is similar to that found at the bovine T-cell receptor alpha delta joining region (pi = 0.00077), but somewhat less than that observed for the bovine leptin (pi = 0.00265). Sequence variation within exon 3 of PRNP in both cattle (pi = 0.00102) and sheep (pi = 0.00171) was greater than that for the complete PRNP gene, with sheep showing greater sequence variation in exon 3 than cattle. The level of sequence variation reported here is greater than previously thought for the bovine PRNP gene in cattle. This study highlights the contribution that recombination plays in increasing allelic diversity in this species.

Amyloid↗
PubMed2001

Pharmaceutical management in ProCare Health Limited.

AIMS: To review pharmaceutical budget holding and management in ProCare Health Limited by; describing budget holding strategies implemented in 1995/6, identifying prescribing savings achieved, analysing variation in prescribing behaviour and comparing the findings with experience elsewhere. METHODS: With 340 members, ProCare is one of the largest and most progressive of New Zealand's independent practitioner associations (IPAs). Data were obtained for the three years 1994 to 1996 to determine pharmaceutical expenditure against budget and against national trends, by member and general medical services (GMS) consultations. RESULTS: ProCare has established a classical, quality focussed pharmaceutical management strategy. Savings against the agreed budget was 9.5% comparing 1996 with 1995 but 5.7% compared, with national trends. Wide variation in per capita and per consultation costs was not reduced and was entirely explained by prescribing volumes not drug prices. CONCLUSIONS: The most important finding is that general practitioners (GPs), working collaboratively, can establish a strategy of clinical and corporate governance which may be exerting a wide ranging influence over clinical behaviour. Although there may be doubts about the actual levels of saving these appeared to be well in excess of the financial investment in the strategy. Greater savings appear possible with a focus on addressing the large and apparently inappropriate per capita prescribing volume variation between practices. Understanding and successfully addressing this variation will be one of the key issues facing the implementation of the government's primary health care strategy.

Cost Savings↗
PubMed1999

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↗
PubMed1998

Bovine microsatellite loci are highly conserved in red deer (Cervus elaphus), sika deer (Cervus nippon) and Soay sheep (Ovis aries).

We tested 174 bovine microsatellite primer pairs for use in a primitive breed of sheep and two species of deer. Of 173 markers, 127 (73.4%) gave a product in Soay sheep (Ovis aries) of which 54 (42.5%) were polymorphic. One hundred and twenty-nine of 174 (74.1%) markers gave a product in red deer (Cervus elaphus) of which 72 (55.8%) were polymorphic. In sika deer (Cervus nippon) 126 of 171 (73.7%) microsatellite primers gave a product with 47 (37.3%) polymorphic. The proportion of bovine microsatellite loci conserved across artiodactyl species was significantly greater in this study than previously reported. Reasons for this high degree of microsatellite conservation are discussed. We suggest that a high resolution comparative map of the artiodactyls can be constructed using microsatellites.

Alleles↗
PubMed1997

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↗
PubMed1997

Effects of 10-ppm hydrogen sulfide inhalation in exercising men and women. Cardiovascular, metabolic, and biochemical responses.

This study examined the acute effects of 10-ppm hydrogen sulfide (H2S) inhalation, a concentration equal to its occupational exposure limit, on the cardiovascular, metabolic, and biochemical responses in healthy volunteers. Fifteen men and 13 women completed two 30-minute exercise sessions at 50% of their maximal oxygen uptake, during which they inhaled medical air or 10 ppm H2S in a blind manner. Arterial and finger-prick blood samples were obtained before and during the final minute of exercise. Muscle biopsies were withdrawn from the right vastus lateralis immediately after exercise. Cardiorespiratory measurements were monitored using an automated metabolic cart interfaced with an electrocardiogram and blood pressure apparatus. A significant decrease in oxygen uptake (VO2), with a concomitant increase in blood lactate, was observed in men and women as a result of H2S exposure. No significant changes were observed in arterial blood parameters and the cardiovascular responses under these conditions. Muscle lactate, as well as the activities of lactate dehydrogenase, citrate synthase, and cytochrome oxidase, were not significantly altered by H2S exposure. However, there was a tendency for muscle lactate to increase and citrate synthase activity to decrease in both genders in the presence of H2S. It appeared that 10-ppm H2S inhalation reduced VO2 during exercise, most likely by inhibiting the aerobic capacity of the exercising muscle. These findings question the scientific validity of the current occupational exposure limit for H2S.

Administration, Inhalation↗
PubMed1996

Effects of 5 ppm hydrogen sulfide inhalation on biochemical properties of skeletal muscle in exercising men and women.

This study compared the acute effects of 5 ppm hydrogen sulfide (H2S) inhalation (50 % of its occupational exposure limit) on the biochemical properties of skeletal muscle in exercising men and women. Twenty-five healthy volunteers, 13 men and 12 women, completed two 30-minute submaximal tests at 50% of their predetermined maximal aerobic power (VO2max) while breathing 0 ppm (control) or 5 ppm H2S from a specially designed flow system in a single-blind manner. Immediately after exercise, biopsies were obtained from the vastus lateralis muscle under local anaesthesia. They were subsequently analyzed for concentrations of the following markers of anaerobic and aerobic metabolism: lactate (La), lactate dehydrogenase (LDH), citrate synthase (CS), and cytochrome oxidase (CytOx). Repeated measures analysis of variance indicated that in men, the CS concentration decreased significantly (p = 0.006) as a result of H2S exposure. There was also a tendency for their La and LDH concentrations to increase and CytOx concentration to decrease in the presence of H2S, but these changes were not significant (p > 0.05). In women no significant changes were observed in any of these biochemical properties. These results suggest that (1) exposure to H2S at 50% of its OEL might inhibit aerobic metabolism during exercise in healthy men, thereby increasing their dependency on anaerobic metabolism; and (2) there could be a significant gender difference in the acute response to sub-OEL exposures of H2S.

Administration, Inhalation↗
PubMed1996

Effects of 10-ppm hydrogen sulfide inhalation on pulmonary function in healthy men and women.

This study examined the acute effects of oral inhalation of 10-ppm hydrogen sulfide (H2S) inhalation (a concentration equal to its occupational exposure limit) on the pulmonary function in healthy men and women. Nine men and ten women consented to inhale medical air or 10 ppm H2S for 15 minutes each during cycle exercise at 50% of their maximal aerobic power. Routine pulmonary function tests were administered at rest and immediately after the two exposure conditions. The results indicated no significant changes in any of the variables derived from the flow volume loop, maximum ventilation volume, and diffusion capacity of the lung for carbon monoxide in both genders. None of the subjects experienced any signs and symptoms as a result of H2S exposure. It was concluded that oral inhalation of 10 ppm H2S at an elevated metabolic and ventilation rate does not significantly alter pulmonary function in healthy men and women.

Adult↗
PubMed1995

Low dose erythromycin regimen for the treatment of chancroid.

Haemophilus ducreyi is the commonest cause of genital ulcer disease in Africa and is associated with heterosexual transmission of human immunodeficiency virus(HIV). The World Health Organization currently recommends erythromycin 500 mg three times a day for seven days as the treatment of choice for Haemophilus ducreyi infection. We studied the effectiveness of a lower dose erythromycin treatment regime, 250 mg three times a day for seven days in the treatment of chancroid. Patients with genital ulcer disease presenting at Nairobi City council clinic between January and March, 1992 were recruited into the study. Swabs were taken from the ulcers for Haemophilus ducreyi and venous blood was screened for syphilis and HIV antibodies. A total of 219 patients were enrolled for the study and were reviewed on days seven and fourteen for side effects, bacteriological and clinical cure rates. 26.4% of the study population were HIV-1 seropositive. The treatment regime was well tolerated and effective in both HIV seropositive and seronegative patients. Complete bacteriological cure rate was achieved in Haemophilus ducreyi culture positives by day seven irrespective of the HIV serostatus. However, the clinical cure rate for HIV seropositive patients was 88% compared to 99% for seronegative patients (p<.001). It is concluded that a low dose erythromycin is an inexpensive and effective treatment for chancroid with complete bacteriological cure rate, although the healing process takes longer in HIV seropositive patients.

Adult↗
PubMed1994

Comparative physiological responses of exercising men and women to 5 ppm hydrogen sulfide exposure.

A study compared the effects of inhalation of 5 ppm hydrogen sulfide (50% of its occupational exposure limit) on the physiological and hematological responses of healthy men and women during exercise. Subjects were 13 men (mean +/- SD for age, height, and weight = 24.7 +/- 4.6 yr, 173 +/- 6.6 cm, 73.1 +/- 8.1 kg, respectively) and 12 women (mean +/- SD for age, height, and weight = 22.0 +/- 2.1 yr, 165 +/- 8.2 cm, 63.4 +/- 8.6 kg, respectively). Subjects completed two 30-minute exercise tests on a cycle ergometer at 50% of their predetermined maximal aerobic power while breathing medical air or 5 ppm H2S from a specially designed flow system. The results indicated that there were no significant differences between the two exposures for the metabolic (oxygen uptake, carbon dioxide production, respiratory exchange ratio), cardiovascular (heart rate, blood pressure, rate pressure product), arterial blood (oxygen and carbon dioxide tensions, pH), and perceptual (rating of perceived exertion) responses in either sex. None of the subjects reported any adverse health effects subsequent to the H2S exposure. These results suggest that healthy men and women can safely perform moderate intensity work in environments contaminated with 5 ppm H2S.

Adult↗
PubMed1992

Effect of high velocity resistance training on peak torque, cross sectional area and myofibrillar ATPase activity.

The purpose of this investigation was to determine the effect of high velocity resistance (HVR) training on peak torque (PT), cross sectional area (CSA) and myofibrillar ATPase activity of the knee extensors. HVR training was performed in a circuit on hydraulic exercise equipment, 4 times a week for 5 weeks at an angular velocity of approximately 3.14 rad.s-1. Knee extension PT was determined on a Cybex II isokinetic dynamometer and CSA of the quadriceps femoris muscle was assessed using computer tomography (CT) scanning. Muscle biopsies were obtained from the lateral quadriceps muscle and were analyzed for myofibrillar ATPase activity. Knee extension peak torque was significantly increased at 1.57, 2.09, 3.14, 3.66 and 4.19 rad.s-1. Myofibrillar ATPase activity and CSA was also significantly increased after HVR training. These findings showed that short-term high velocity resistance training enhances the in vivo torque/velocity curve especially at fast angular velocities and these changes are partly attributed to an increase in muscle CSA and activity of myofibrillar ATPase.

Adaptation, Physiological↗
PubMed1986

Coordination of Ca2+ regulating and Ca2+ regulated processes in the study of muscle function.

The self-organization of biological systems is, in part, described by dynamical order and cooperativity of system elements. Consideration of this, therefore, should form the infrastructure of future Exercise/Sport Biochemistry Research in Canada since a solely elemental focus, in its' interpretation, may not be meaningful if the synergy among system elements is not appreciated. This approach is illustrated through a description of the central role of Ca2+ metabolism in coordinating subcellular events associated with muscle contraction. The decline in force generating capabilities associated with extreme muscle use (e.g. endurance type exercise) is, in our view, due to an uncoupling of excitation-contraction coupling leading a Ca2+ imbalance. The observed dissolution of the myofibril ultrastructure and altered SR function reflect a loss of normal order and synergy amongst Ca2+ regulated and Ca2+ regulating processes which will lead to an upcoupling of oxidative phosphorylation. These apparently catastrophic events may, paradoxically, establish a new order in which energy utilizing systems attempt to keep pace with the abbreviated energy production system.

Animals↗
PubMed1982

Plasmid-mediated sulfonamide resistance in Haemophilus ducreyi.

Clinical isolates of Haemophilus ducreyi from patients with chancroid were shown to have one or more 4.9- to 7.0-megadalton non-self-transferable plasmids and to have in vitro resistance to sulfonamides. Transformation of Escherichia coli to sulfonamide resistance was associated with the acquisition of a 4.9-megadalton plasmid, which did not confer linked resistance to streptomycin. The guanine-plus-cytosine content of this plasmid was found to be 57%. Filter-blot hybridization and restriction endonuclease digestion studies suggested a relationship of this plasmid to RSF1010. Electron microscope heteroduplex analysis confirmed this relationship. The identification in H. ducreyi of a plasmid closely related to plasmids found in enteric species, rather than transposition of a resistance determinant to an indigenous plasmid, suggests that further dissemination of the enteric plasmid pool to this genus is possible since plasmid transfer between certain Haemophilus species is readily demonstrated.

Endonucleases↗
PubMed1980

"Asset stripping" the declining mental hospital.

A psychogeriatric day hospital was developed from a long-stay back ward of a large mental hospital whose population of patients had decreased by half. Women in the 70-80 age group with varying degrees of dementia benefited most from such facilities. In view of the current cut-back in Government spending one of the greatest assets in providing a comprehensive service for the elderly mentally infirm may well be found in the declining mental hospital.

Aged↗