Search PubMed⌕ Search

Biomedical subjects

J C Sharp

Publications and source records attributed to J C Sharp.

At least 19 recordsLinked to original sources
PubMed2001

A unique insight into the incidence of rugby injuries using referee replacement reports.

OBJECTIVES: To obtain further information the incidence of injuries and playing positions affected in club rugby in Scotland. METHODS: Routine reports of injury (permanent) and blood (temporary) replacements occurring in competitive club rugby matches by referees to the Scottish Rugby Union during seasons 1990-1991 to 1996-1997 were analysed. RESULTS: A total of 3,513 injuries (87 per 100 scheduled matches) and 1,000 blood replacements (34 per 100 scheduled matches) were reported. Forwards accounted for 60% of the injury and 72% of the blood replacements. Flankers and the front row were the most commonly replaced forwards while wing and centre three quarters were the most vulnerable playing positions among backs. The incidence of injury replacements increased as the match progressed up until the last 10 minutes when the trend was reversed. Blood replacements showed a different pattern with 60% occurring during the first half of the match. CONCLUSION: The most important finding of the study was reliability of referees in documenting the vulnerability of certain playing positions, and the timing when injuries took place, thus assisting coaches and team selectors when choosing replacement players for competitive club and representative rugby matches. This study re-emphasises the need for continuing epidemiological research.

Football↗
PubMed2000

Analysis of ovariectomy and estrogen effects on body composition in rats by X-ray and magnetic resonance imaging techniques.

Resistance of bone to fracture--bone strength--has been shown to depend on both the amount of bone and its architectural spatial organization. In vivo magnetic resonance (MR) techniques have the capability of imaging bone tissue, including the trabecular microarchitecture and the marrow composition. We have applied in vivo and ex vivo MR methods to the tibia in an ovariectomized rat model of osteoporosis. Specifically, in vivo high-resolution three-dimensional MR imaging and localized MRS were facilitated by specialized coils and high field magnets, resulting in enhanced sensitivity of detection. As a result, in vivo and ex vivo differences in marrow composition were found between sham-ovariectomized, ovariectomized, and ovariectomized animals treated with 17-beta-estradiol. Estrogen effects were detected in vivo 7 days after surgery (3 days into treatment) as a decrease in the tibial fat signal level. The in vivo effects of ovariectomy were observed 56 days after surgery as an increase in MR image fat signal level and spectral fat/water ratio in the proximal tibia. Ex vivo measurements of tibial marrow water signal discriminated clearly between the sham and ovariectomized groups and showed increased individual variations in the treatment group. Imaging further showed that the highest fat content is observed in the epiphysis. Computed tomography confirmed ovariectomy-induced loss of bone in the proximal tibial metaphysis compared with the sham group. This loss of cancellous bone with ovariectomy is consistent with the MR observations of increases in both fat and water in the metaphysis. These data showed that MR techniques complement X-ray techniques in the bone, water, and fat compositional analysis of the appendicular skeleton in response to ovariectomy and pharmacological treatment.

Adipose Tissue↗
PubMed1999

MR spectroscopy using multi-ring surface coils.

A spatially uniform B(1)-field is preferred for MR imaging and spectroscopy. Unfortunately, volume coils are sometimes unavailable, or do not provide adequate RF power or SNR for some applications. In quantitative MRS, mean metabolite concentration cannot be evaluated when the coil response is nonuniform, unless an assumption is made concerning the metabolite spatial distribution. It is well known that standard single-loop surface coils, although offering high SNR characteristics, have poor B(1) homogeneity. New multi-ring surface coils are proposed which produce a locally uniform B(1) field, with sensitivity and power requirements comparable to those of standard surface coils. MR spectroscopy using two and three-ring versions of this "local volume coil" result in spatial localization essentially identical to that obtained with a volume coil but with much improved RF power and SNR characteristics. When compared to standard surface coils, the multi-ring coil offers much improved water suppression and localization, as well as reduced outer voxel contamination, with only a small loss in SNR and moderate increase in SAR. In summary, the multi-ring coil operates midway between the volume coil and the standard surface coil, retaining the most advantageous properties of both. Magn Reson Med 42:655-664, 1999. Published 1999 Wiley-Liss, Inc.

Humans↗
PubMed1998

Measurements of human breast cancer using magnetic resonance spectroscopy: a review of clinical measurements and a report of localized 31P measurements of response to treatment.

A review of the literature has shown that in human breast tumours, large signals from phosphomonoesters (PME) and phosphodiesters (PDE) are evident. In serial measurements in 19 patients with breast cancer, a decrease in PME was significantly associated with a stable or responding disease (p = 0.017), and an increase in PME was associated with disease progression. Extract studies have shown PME to comprise of phosphoethanolamine (PEth) and phosphocholine (PCho), with the PEth to PCho ratio ranging from 1.3 to 12. The PCho content of high grade tumours was found to be higher than low grade tumours. In some animal models, changes in PCho have been shown to correlate with indices of cellular proliferation, and spheroid studies have shown a decrease in PCho content in spheroids with smaller growth fractions. A serial study of 25 patients with advanced primary breast tumours undergoing hormone, chemotherapy or radiotherapy treatments, showed that in this heterogenous group there were significant changes in metabolites that were seen during the first 3 weeks (range 2-4 weeks) of treatment, that correlated with volume change over this period, employed here as a measure of response. Changes in PME (p = 0.003), total phosphate (TP) (p = 0.008) and total nucleoside tri-phosphate (TNTP) (p = 0.02) over 3 (+/-1) weeks were significantly associated with response, as were the levels of PME (p<0.001), PDE (p = 0.01), TP (p = 0.001) and TNTP (p = 0.007) at week 3 (+/-1). PME at week 3 (+/-1) was also significantly associated with the best volume response to treatment (p = 0.03). A reproducibility analysis of results from the observation of normal breast metabolism in four volunteers showed a mean coefficient of variation of 25%, after correcting for changes resulting from the menstrual cycle. Reproducibility studies in four patients with breast cancer showed a mean coefficient of variation of 33%, with the reproducibility being better in patients measured on different days (difference in TP was -6%) compared with those measured on the same day (difference in TP was -29%).

Adult↗
PubMed1998

Environmental risk factors for sporadic Escherichia coli O157 infection in Scotland: results of a descriptive epidemiology study.

The objective of the study was to obtain detailed descriptive epidemiological information on sporadic verocytotoxin-producing Escherichia coli O157 infection in Scotland in relation to transmission routes and host-related risk factors. Using a standardized questionnaire, the study was carried out throughout Scotland over an 18-month period from July 1992 and co-ordinated at the Communicable Diseases and Environmental Health (Scotland) Unit, Glasgow (CDEH(S)U). The subjects were laboratory-confirmed cases of Escherichia coli O157 infection, of whom 138 met the criteria for inclusion in the study. The most important findings were the high proportion of cases who had been exposed to environmental factors such as farm animals and/or their by-products; or who had participated in gardening or garden-play; or who had suspected or confirmed household water supply problems, prior to the onset of illness. The frequency and relative importance of environmental risk factors requires further quantification and study in order to assess where control measures can be directed most effectively. The implications for the NHS in preventing this crippling, life-threatening infection are considerable, not least in relation to hospitalization, dialysis and renal transplantation costs.

Adult↗
PubMed1995

NMR microscopy of single neurons using spin echo and line narrowed 2DFT imaging.

NMR microimages of single neural cells were acquired at 500 MHz using a conventional spin echo pulse sequence and a line-narrowing sequence that eliminates susceptibility effects. The data show that any contribution to the measured T2 relaxation rate arising from diffusion in local field inhomogeneities using spin echo sequences at high fields and high spatial resolution is relatively small. We conclude that the measured T2 difference between the nucleus and cytoplasm in these cells represents primarily a true T2 relaxation effect arising from the interactions of water with macromolecules in the two compartments and does not result from microsusceptibility differences. These observations have implications regarding water compartmentation in single cells and the interpretation of the MR characteristics of tissues in vivo.

Animals↗
PubMed1995

The association between typhoid carriage, typhoid infection and subsequent cancer at a number of sites.

It has been demonstrated that bacteria can produce the very potent carcinogens (N-nitroso compounds), from nitrite and suitable amines. It has been hypothesized that this can happen whenever a body site which is normally sterile becomes colonized by bacteria. If this is so then such chronic infections should result in an increased incidence of local cancers and also of cancers at some distant sites. To test this we studied the risk of cancer at various sites in a cohort of chronic carriers of Salmonella typhi/paratyphi. We have observed a greatly increased risk of cancers of the biliary tract and also of cancers of the colorectum, pancreas, lung and all sites. The results are discussed in terms of the hypothesis being tested.

Adolescent↗
PubMed1994

Cancer mortality in chronic typhoid and paratyphoid carriers.

It has been shown in vitro that bacteria are able to form or release carcinogens, mutagens, or promoters from intestinal secretions such as bile, or from excretions such as urine. It is, therefore, of interest to find out whether chronic infection of the gallbladder is associated with carcinogens, as in chronic infection of the urinary bladder. A study of cancer risk in chronic typhoid and paratyphoid carriers showed a large excess (observed/expected cases) for cancer of the gallbladder (167.0; 95% confidence interval 54.1-389) and also excess risks of cancer of the pancreas (8.1), colorectum (3.0), lung (2.5), and all neoplasms (2.6). There was no similar excess risk in a group of 386 people with typhoid from the 1964 Aberdeen outbreak. This indicates that it is long-term typhoid carriage, not acute infection, which is the risk factor. This has important implications for cancer prevention. Eradication of chronic carriage, by use of antibiotics or elective cholecystectomy, should be re-emphasised, and the need for good documentation of carriers is, therefore, of great importance.

Adult↗
PubMed1994

NMR microscopy of hydrating hydrophilic matrix pharmaceutical tablets.

NMR microscopy has been used to monitor the formation of the gel layer in hydrating hydrophilic polymer tablets. Such tablets are used in the controlled delivery of drugs, where it has been found that the rate and extent of the swelling of the outer gel layer critically influences the kinetics of drug release. Tablets were hydrated in distilled water at 37 degrees C and then imaged at discrete time intervals using a 500 MHz microscope. The growth of the gel layer was clearly observed in time sequences of radial and axial sections. Axial images showed some interesting dimensional changes, with the gel at the flat surface of the tablet developing a concave shape. This is probably a reflection of the occurrence of uni-axial stress relaxation as hydration proceeds. Diffusion- and T2-weighted images provided evidence that the water in the gel layer is more strongly bound close to the dry core of the tablet than at the more fully hydrated outer surface. In images of tablets containing diclofenac, disruption of the gel layer was shown to occur primarily from the flat surfaces of the tablet, whilst the distribution of particles could be seen in tablets doped with insoluble calcium phosphate.

Diclofenac↗
PubMed1994

High incidence of haemorrhagic colitis due to Escherichia coli O157 in one Scottish town: clinical and epidemiological features.

Verotoxin-producing strains of Escherichia coli (VTEC), in particular serotype O157:H7, are now recognised as the major cause of haemorrhagic colitis and the haemolytic uraemic syndrome (HUS) in the U.K. and in North America, and increasingly so in other countries. Over a 3-year period (1989-1991), 16 cases of E. coli 0157 infection occurred in one town (Peterhead) in north-east Grampian. Four patients required admission to hospital, of whom three developed HUS. The bovine source of VTEC infection has now been clearly established with foodborne, waterborne, person-to-person and zoonotic transmission described. Despite extensive local enquiries, the source(s) of infection of the 16 cases in Peterhead was not established. Much still needs to be learned about the epidemiology, risk factors and long-term clinical sequelae of VTEC infection and HUS. Close collaboration between the medical and veterinary professions is of paramount importance in order to provide better understanding of the prevalence of E. coli O157 infection in cattle and the route(s) of transmission to humans.

Adolescent↗
PubMed1994

An outbreak of Escherichia coli O157 associated with a children's paddling pool.

In May 1992, a small, circumscribed community outbreak of infection due to verotoxin-producing Escherichia coli O157 phage type 49 occurred in a semi-rural area of south-east Scotland. On the basis of stool cultures, six cases were identified, one of whom was asymptomatic. One child developed the haemolytic uraemic syndrome. Although the source of infection of the index case was not established nor could the extent of person-to-person spread be fully determined, the clinical, microbiological and epidemiological evidence available indicated that a children's paddling pool served as the focal point in the transmission of infection causing the outbreak.

Child, Preschool↗
PubMed1994

Infection caused by Escherichia coli O157:H7 in Alberta, Canada, and in Scotland: a five-year review, 1987-1991.

Infections and life-threatening complications due to verotoxin-producing Escherichia coli (VTEC) have been increasingly recognized as a public health problem in recent years. Through enhanced surveillance in Alberta, Canada, and in Scotland, 1,993 cases of VTEC infection and 115 cases of hemolytic-uremic syndrome (HUS) were detected in 1987-1991 in a combined population of more than 7.5 million; there were 24 deaths. The mean annual rates of VTEC infection were 12.1/100,000 and 2.0/100,000 for Alberta and Scotland, respectively. One case of HUS occurred for every 14 (Scotland) to 19 (Alberta) cases of VTEC infection. Rates of VTEC infection were highest among children < 5 years of age, while rates of resultant hospitalization were highest among the elderly. Male-to-female ratios for patients with VTEC infection varied with the age group. The incidence of this infection was highest in the summer: 64.0%-81.7% of cases occurred between May and September. Hamburger was the most common source reported. Unexplained geographic variation in prevalence was evident in both Alberta and Scotland. Most cases were sporadic, although several community and point-source outbreaks were identified in Scotland. HUS exhibited similar epidemiological patterns. Infections with VTEC impose a substantial preventable clinical and public health burden. Routine monitoring of these infections is considered worthwhile in order to elucidate their epidemiology and modes of transmission and ultimately to control them more effectively.

Adolescent↗
PubMed1993

Elimination of susceptibility distortions and reduction of diffusion attenuation in NMR microscopy by line-narrowed 2DFT.

NMR imaging at high field strengths is adversely affected by magnetic susceptibility variations within the specimen. This is especially true in NMR microscopy. We present results using a line-narrowed imaging sequence which overcomes the image distortions associated with the frequency encoded readout method. Signal attenuation due to diffusion in static magnetic field gradients is also reduced.

Artifacts↗
PubMed1993

Enteric fever in Scotland 1975-1990.

In the 16-year period 1975-90, there were 267 cases of acute infection with typhoidal salmonellae reported in Scotland, in addition to which 32 chronic carriers were identified. The overall incidence of disease changed little over this period, but there was a fall in indigenously acquired paratyphoid B and typhoid, and a rise in imported paratyphoid A. The majority, 215 (81%), had a history of recent travel and were considered to have acquired infection overseas. Only six of the indigenously acquired infections were traced to acutely infected persons, illustrating the low risk of transmission associated with acute enteric fever in the UK. Only one death was definitely ascribed to enteric fever, and one person with S. paratyphi B became a chronic carrier. Significant illness was observed in five chronically infected individuals, including one with carcinoma of the gallbladder. UK residents of 'Asian' ethnicity returning from the Indian subcontinent accounted for 63 (46%) of the 137 cases of typhoid, and 34 (64%) of the 53 cases of paratyphoid A. People of 'Asian' ethnicity were more likely to have acquired infection overseas than 'non-Asians': 110 (89%) of 123 persons compared with 105 (73%) of 144 (odds ratio 3.1, 95% confidence interval 1.5-6.6, P = 0.001). Although there seems to be limited scope for preventing indigenously acquired infection, immunisation of travellers could contribute significantly to reducing the incidence of typhoid.

Acute Disease↗