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Biomedical subjects

M J Crowe

Publications and source records attributed to M J Crowe.

At least 19 recordsLinked to original sources
PubMed2006

Effects of static stretching on leg power during cycling.

AIM: This study investigated the effects of warm-up involving static stretching on leg power. It was expected that the inclusion of static stretching in the warm-up would decrease leg power. METHODS: Twenty-seven healthy volunteers (16 male, 11 female) participated in the study. A prospective, repeated measures design was implemented where volunteers underwent 2 testing sessions at least 24 hours apart. One testing session involved a control warm-up (5 min submaximal cycling) followed by 4 10-s leg power tests at 5, 20, 40 and 60 min postwarm-up. For the other testing session, the subjects performed 5 min of submaximal cycling followed by 15 min of lower body static stretching and then the four leg power tests. Relative peak power, time to peak power and relative total work were measured for each leg power test. RESULTS: Peak power and total work were significantly greater after the static stretching warm-up compared to the control warm-up on all power tests. Peak power was achieved more quickly for the static stretching warm-up compared to the control warm-up on the 5 min test only. CONCLUSIONS: A warm up that includes static stretching has beneficial effects on anaerobic power events in comparison to submaximal cycling alone.

Adult↗
PubMed2003

Employment of broad-range 16S rRNA PCR to detect aetiological agents of infection from clinical specimens in patients with acute meningitis--rapid separation of 16S rRNA PCR amplicons without the need for cloning.

AIMS: The aim of this study was to develop a polyacrylamide gel electrophoresis (PAGE) method for the rapid separation of 16S rRNA PCR amplicons from aetiological agents of acute meningitis. METHODS AND RESULTS: Blood samples from 40 patients with suspected acute meningococcal meningitis were examined for the presence of causal agents, including Neisseria meningitidis employing two methods: (i) broad-range 16S rRNA PCR in conjunction with PAGE and automated sequencing and (ii) species-specific PCR employing ABI TaqMan technology for N. meningitidis. Analysis of clinical specimens employing 16S rRNA PCR yielded 33/40 (82.5%) positive for the presence of bacterial DNA. Species-specific PCR yielded 30/40 (75%) clinical specimens positive for N. meningitidis. Prior to separation by PAGE, only 6/33 (18.2%) amplicons were able to be identified by sequence analysis, the remaining amplicons (n=27) did not yield an identification due to the presence of mixed 16S rRNA PCR amplicons. Following separation, amplicons were re-amplified and sequenced, yielding 24/27 (88.9%) positive for N. meningitidis and three specimens positive for Acinetobacter sp., Staphylococcus aureus and Streptococcus pneumoniae. One specimen was positive for both N. meningitidis and Streptococcus spp. and another specimen was positive for N. meningitidis and Pseudomonas sp., by broad-range PCR. Seven clinical specimens were negative for N. meningitidis and other eubacteria using both detection techniques. CONCLUSIONS: Clinical specimens including blood and cerebrospinal fluid from patients with suspected acute bacterial meningitis, may become contaminated with commensal skin flora, resulting in difficulties in downstream sequencing of pathogen plus contaminant DNA. This study allows for the rapid separation of amplified pathogen from contaminant DNA. SIGNIFICANCE AND IMPACT OF STUDY: This study demonstrated the usefulness of the rapid separation of multiple 16S rRNA PCR amplicons using a combination of PAGE and automated sequencing, without the need of cloning. Adoption of this technique is therefore proposed when trying to rapidly identify pathogens in clinical specimens employing broad-range 16S rRNA PCR.

Acinetobacter↗
PubMed2003

Effects of beta-hydroxy-beta-methylbutyrate and creatine monohydrate supplementation on the aerobic and anaerobic capacity of highly trained athletes.

AIM: The aim of this study was to investigate the effects of 6 wks oral supplementation of beta-hydroxy-beta-methylbutyrate (HMB) and a mixture of HMB and creatine monohydrate (HMBCr) on aerobic and anaerobic capacity in highly trained athletes. It was hypothesised that HMB and HMBCr would have positive effects on aerobic and anaerobic power. METHODS: A prospective study involving a repeated measures design was utilised where subjects underwent testing prior to, and immediately after, a 6 wks supplementation period. Elite, male rugby league players (n=27) were divided into 3 groups, a control group (n=6), a HMB group (3 g/d; n=10) and a HMBCr group (3 g/d HMB + 3 g/d Cr; n=11). Testing involved a multistage fitness test to determine aerobic power and a 60 sec maximal cycle test to determine anaerobic capacity. Peak power, total work and peak lactate levels were measured in the anaerobic cycle test. RESULTS: Two-way repeated measures ANOVA revealed no effect of HMB or HMBCr on any of the measured parameters in comparison to the control group. CONCLUSION: Aerobic and anaerobic ability of highly trained male athletes is unaffected by 6 wks oral supplementation with HMB or a combination of HMB and creatine monohydrate.

Administration, Oral↗
PubMed2002

Trends in bacteraemia on the haematology and oncology units of a UK tertiary referral hospital.

As part of ongoing surveillance of infection in the haematology and oncology units at Belfast City Hospital, microbiologically documented bloodstream infections over three 12-month periods 1994/5, 1998/9 and 1999/00 were reviewed. Gram-positive organisms were the most common cause of blood stream infection in the haematology unit causing 66%, 56% and 64% of episodes of monomicrobial bacteraemia in 1994/5, 1998/9 and 1999/00, respectively. In haematology patients, enterococci have emerged as an important cause of bacteraemia, with increasing levels of glycopeptide resistance, and the 'non-fermenting Gram-negative rods other than Pseudomonas aeruginosa' are an increasingly common cause of monomicrobial and polymicrobial bacteraemia. In oncology patients, Gram-negative organisms (predominantly enterobacteriaceae) were more common than Gram-positive organisms, causing 50% and 54% of monomicrobial bacteraemia in 1998/9 and 1999/00, respectively. Changes in patient population, underlying diseases and chemotherapeutic agents may explain these findings. The spectrum of infection seen in haematology and oncology patients changes as management evolves. Ongoing co-operation between haematologists, oncologists and microbiologists is important to detect trends in epidemiology, which can be used to design empirical antibiotic regimens and guide infection control policies.

Adolescent↗
PubMed2001

Long-term preservation of strains of Burkholderia cepacia, Pseudomonas spp. and Stenotrophomonas maltophilia isolated from patients with cystic fibrosis.

Long-term preservation methods are important in the maintenance of bacteria for downstream research applications. Most clinical laboratories have only limited resources for archiving isolates and therefore require cost-effective and simple methods. An effective and cheap storage method using debrinated blood and maintenance at -80 degrees C is described.

Bacteriological Techniques↗
PubMed2000

Delayed wound healing in immunodeficient TGF-beta 1 knockout mice.

Previous studies showed that full-thickness wounds in transforming growth factor-beta1-deficient mice initially heal normally. Unfortunately, transforming growth factor-beta1 deficiency leads to a multifocal inflammatory disease affecting most organs of the body, which ultimately interferes with later stages of wound healing in these mice. As this inflammatory disease is eliminated in transforming growth factor-beta1-deficient mice lacking T and B cells (Tgfb1-/- Scid-/- mice), we hypothesized that wound repair in the latter would proceed normally, even at later stages of healing. Unexpectedly, Tgfb1-/- Scid-/- mice demonstrate a major delay of approximately 1 wk in each of the major phases of wound healing: inflammation, proliferation, and maturation. Immuno- deficient Scid-/- mice that have the wild-type Tgfb1 allele do not experience this delay in wound healing. One interpretation of these findings is that lymphocytes and transforming growth factor-beta1 affect compensatory pathways in wound healing. An alternative interpretation is that the delayed expression of Tgfb2 and Tgfb3 that occurs in the absence of transforming growth factor-beta1 results in the delayed wound healing, suggesting that transforming growth factor-beta2 and/or transforming growth factor-beta3 play important parts in wound healing.

Animals↗
PubMed1999

The Nf1 tumor suppressor regulates mouse skin wound healing, fibroblast proliferation, and collagen deposited by fibroblasts.

Neurofibromatosis type 1 patients develop peripheral nerve tumors (neurofibromas) composed mainly of Schwann cells and fibroblasts, in an abundant collagen matrix produced by fibroblasts. Trauma has been proposed to trigger neurofibroma formation. To test if loss of the neurofibromatosis type 1 gene (Nf1) compromises fibroblast function in vivo following trauma, skin wounding was performed in Nf1 knockout mice. The pattern and amount of collagen-rich granulation bed tissue, manufactured by fibroblasts, was grossly abnormal in 60% of Nf1+/- wounds. Nf1 mutant fibroblasts showed cell autonomous abnormalities in collagen deposition in vitro that were not mimicked by Ras activation in fibroblasts, even though some Nf1 effects are mediated through Ras. Nf1+/- skin wound fibroblasts also proliferated past the normal wound maturation phase; this in vivo effect was potentiated by muscle injury. In vitro, Nf1+/- fibroblasts showed higher proliferation in 10% serum than Nf1+/+ fibroblasts. Macrophage-conditioned media or epidermal growth factor potentiated Nf1+/- fibroblast proliferation in vitro, demonstrating abnormal response of mutant fibroblasts to wound cytokines. Thus Nf1 is a key regulator of fibroblast responses to injury, and Nf1 mutation in mouse fibroblasts causes abnormalities characteristic of human neurofibromas.

Animals↗
PubMed1999

Medicinal yeast extracts.

Alcoholic extracts of bakers' yeast (Saccharomyces cerevisiae) have been used for over 60 years in over-the-counter medications for the treatment of hemorrhoids, burns, and wounds. Although previous studies suggested that small peptides were responsible for the medical observations, the peptides were never resolved into separate fractions and identified. In the present report, a protein fraction was prepared by RPC18 chromatography of the extract which enhances wound closure in both diabetic and non-diabetic littermates. The peptides are active in nanomolar amounts and are 600 times more active than the initial extract. SDS-PAGE and N-terminal amino acid sequencing identified 4 polypeptides in the extract. Three of the proteins were small molecular weight stress-associated proteins: copper, zinc superoxide-dismutase, ubiquitin, and glucose lipid regulated protein (HSP 12). The fourth protein, acyl-CoA binding protein II, has not been previously associated with stress proteins.

Amino Acid Sequence↗
PubMed1998

Review of case definitions for nosocomial infection--towards a consensus. Presentation by the Nosocomial Infection Surveillance Unit (NISU) to the Hospital Infection Liaison Group, subcommittee of the Federation of Infection Societies (FIS).

As part of the preparatory work for a national surveillance scheme, consensus was sought on the case definitions for nosocomial infection. We compare six sets of case definitions for nosocomial urinary tract infection, surgical wound infection, bloodstream infection and pneumonia, and highlight areas of agreement and variation. We hope this will stimulate discussion among those with expertise and interest in surveillance and so contribute to the development of nationally agreed case definitions.

Bacteremia↗
PubMed1997

Co-ordination of contractile activity in guinea-pig mesenteric lymphatics.

1. Intraluminally perfused lymphatic vessels from the mesentery of the guinea-pig were examined in vitro to investigate their contractile activity and the co-ordination of this activity between adjacent lymphangions. 2. Lymphangions constricted at fairly regular intervals and exhibited 'refractory' periods of up to 3 s during which constrictions did not occur. 3. The contractile activity of adjacent lymphangions was highly co-ordinated. 4. The smooth muscle was found to be continuous between the adjacent lymphangions for the majority of valve regions examined morphologically (52 of 63 preparations). 5. Mechanical and electrical coupling between adjacent lymphangions was indicated, as some lymphangions underwent transient dilatations just prior to constriction, whereas direct electrophysiological measurements showed that the smooth muscle of most adjacent lymphangions was electrically coupled across the valve (15 out of 20 pairs of lymphangions). 6. It is concluded that perfused lymphangions of guinea-pig mesenteric lymphatic vessels rhythmically constrict, with the contractile activity of adjacent lymphangions highly co-ordinated. The findings also indicate that transmission of both mechanical and electrical signals between the adjacent lymphangions contribute to the co-ordination of their contractile activity.

Animals↗
PubMed1997

Apoptosis and delayed degeneration after spinal cord injury in rats and monkeys.

Apoptosis is a morphologically defined form of programmed cell death seen in a variety of circumstances, including immune cell selection, carcinogenesis and development. Apoptosis has very recently been seen after ischemic or traumatic injury to the central nervous system (CNS), suggesting that active cell death as well as passive necrosis may mediate damage after CNS injury. After spinal cord injury (SCI) in the rat, typical post-traumatic necrosis occurred, but in addition, apoptotic cells were found from 6 hours to 3 weeks after injury, especially in the spinal white matter. Apoptotic cells were positive for oligodendrocyte markers. After SCI in monkeys, apoptotic cells were found within remote degenerating fiber tracts. Both secondary degeneration at the site of SCI and the chronic demyelination of tracts away from the injury appear to be due in part to apoptosis. As cytokines have been shown to mediate oligodendrocyte death in vitro, it seems likely that chronic demyelination after CNS injury shares features with chronic degenerative disorders like multiple sclerosis.

Animals↗
PubMed1996

Endothelium-dependent modulation of pacemaking in lymphatic vessels of the guinea-pig mesentery.

1. Endothelial control of the rate of constrictions and the underlying pacemaker potentials has been studied in vitro in guinea-pig mesenteric lymphatic vessels. 2. ACh stimulated 60% of intraluminally perfused vessels to slow or abolish lymphatic constrictions. This action was inhibited by atropine and was likely to be due to the release of endothelium-derived nitric oxide (EDNO) as the effect was absent after endothelial lysis, mimicked by sodium nitroprusside (SNP), blocked by N omega-nitro L-arginine (NOLA) and partially inhibited by Methylene Blue (MB). 3. The remaining 40% of perfused vessels did not mechanically respond to ACh or SNP. In four of seven such vessels this appeared to be due to excessive perfusion-associated release of EDNO, as incubation with NOLA restored the response to SNP. 4. Application of NOLA or MB in perfused vessels significantly increased constriction frequency, further indicating perfusion-associated release of EDNO. 5. ACh induced a marked increase in endothelial [Ca2+]i of both mechanically responding and non-responding vessels. This ACh-induced increase could be repetitively induced when Ca2+ was present in the perfusate, but rapidly ran down when a Ca(2+)-free EGTA perfusate was used. 6. Intracellular recordings from the smooth muscle of non-perfused vessel segments demonstrated an ACh-induced hyperpolarization and decrease in membrane resistance, changes which were prevented by atropine, NOLA, MB and endothelial lysis and mimicked by SNP. 7. ACh directly reduced the size of the underlying pacemaker potentials termed spontaneous transient depolarizations (STDs). 8. NOLA and MB enhanced STDs in non-perfused vessel segments indicating an endogenous release of EDNO. 9. It is concluded that the lymphatic endothelium produces and releases EDNO endogenously, during perfusion or after stimulation with ACh, to decrease the efficacy of STDs to generate action potentials and resultant constrictions.

Acetylcholine↗
PubMed1995

Distribution of NADPH-diaphorase reactivity in the spinal cord of metamorphosing and adult Xenopus laevis.

The histochemical NADPH-diaphorase reaction has identified distinct neuronal populations in the nervous system of several species. Considerable evidence suggests that NADPH-d is a neuronal nitric oxide synthase (NOS). We examined spinal cords of adult and metamorphosing Xenopus laevis (XL) for developmental differences in NADPH-d reactivity. In adult XL, labeling was found in all dorsal root ganglia (DRGs) and in their termination sites within the dorsal horn (cutaneous afferent field) and intermediate gray (muscle afferent field). Cell bodies in the intermediate gray regions containing the autonomic preganglionic neurons were labeled in thoracic and sacral sections. Neurons located in the medial (MMC) and lateral motor columns (LMC) of the ventral horn were also stained. In metamorphosing XL, reactivity was detected in neurons in the intermediate gray, in the MMC and in the LMC as in the adult. Additionally, primary motoneurons including those innervating tail musculature were labeled. Neurons in the DRGs were stained at all stages; in the dorsal horn, the density of staining reflected the development of the sensory afferent fields. The conservation of NADPH-d reactivity in adult and metamorphosing XL spinal neurons suggests that NOS may be involved in processes independent of developmental changes occurring in XL spinal cord.

Animals↗
PubMed1992

Species differences in amphibian olfactory neuron reactivity to a monoclonal antibody.

A monoclonal antibody immunostained a subpopulation of olfactory sensory neurons in cryostat sections of the olfactory mucosa of the grass frog, Rana pipiens, and the bullfrog, Rana catesbeiana. However, in the olfactory tissues of the African clawed frog, Xenopus laevis, only mucus and mucus-secreting components were stained, and no cell-specific immunoreactivity was seen in the tiger salamander, Ambystoma tigrinum. This antibody is a useful marker of olfactory neuronal subpopulations in some amphibians and illustrates the difficulties in cross-species immunocytochemistry.

Ambystoma↗
PubMed1992

Aquagenic urticaria.

Aquagenic urticaria is a rare form of physical urticaria characterized by small follicular wheals with an erythematous flare upon exposure to water. We describe typical lesions in a seven-year-old boy with aquagenic urticaria, cholinergic urticaria, and symptomatic dermatographism, who responded to treatment with ultraviolet B and oral antihistamines.

Child↗