PubMed Health⌕ Search

Biomedical subjects

R N Matthews

Publications and source records attributed to R N Matthews.

At least 19 recordsLinked to original sources
PubMed2006

Orexin receptor expression in human adipose tissue: effects of orexin-A and orexin-B.

Orexin-A and orexin-B, via their receptors orexin-1 receptor (OX1R) and orexin-2 receptor (OX2R) have been shown to play a role in the regulation of feeding, body weight, and energy expenditure. Adipose tissue also contributes significantly to the maintenance of body weight by interacting with a complex array of bioactive peptides; however, there are no data as yet on the expression of orexin components in adipose tissue. We, therefore, analyzed the expression of OX1R and OX2R in human adipose tissue and determined functional responses to orexin-A and orexin-B. OX1R and OX2R mRNA expression was detected in subcutaneous (s.c.) and omental adipose tissue and in isolated adipocytes. Protein for OX1R and OX2R was also detected in whole adipose tissue sections and lysates. Treatment with orexin-A, and orexin-B (100 nM, 24 h) resulted in a significant increase in peroxisome proliferator-activated receptors gamma-2 mRNA expression in s.c. adipose tissue (P < 0.05). Hormone sensitive lipase mRNA was significantly reduced in omental adipose tissue with orexin-A and orexin-B treatment (P < 0.05). Glycerol release from omental adipose tissue was also significantly reduced with orexin-A treatment (P < 0.05). These findings demonstrate for the first time the presence of functional orexin receptors in human adipose tissue and suggest a role for orexins in adipose tissue metabolism and adipogenesis.

Adipocytes↗
PubMed2002

Experience of explantation of Trilucent breast implants.

On 6 June 2000, the Medical Devices Agency (MDA) recommended that all Trilucent (soya-bean-oil filled) breast implants should be removed. This accelerated a trend that had already begun in our unit. This study follows our previous report on a 3 year series of women with Trilucent breast implants. The aim was to present our operative findings at explantation, and to correlate them with the preoperative signs and symptoms, the postoperative complications and the details of the hospital stay. In total, 44 patients (82 implants) underwent explantation, of whom 34 were cosmetic cases and 10 were reconstructive. Five patients had their implants removed before the MDA announcement. Implant rippling was the most common problem reported (25%), followed by pain (18%), implant deflation (9.1%) and capsular contracture (4.5%). Free oil was seen around the implant in 15 cases; four of these presented with clinical deflation, and three with rippling. The remaining eight patients were asymptomatic. We conclude that these implants tend to bleed, as evidenced by the presence of free oil around the implant in 34% of patients. The absence of free oil in 73% of the patients who presented with rippling suggests that the leaking oil is often metabolised and absorbed. The findings of this study are significant for women in whom free oil was found around the implant during explantation, and for those who still have Trilucent implants in place, for whatever reason, in spite of the MDA recommendation.

Adult↗
PubMed2001

Trilucent breast implants: a 3 year series.

The use of Trilucent breast implants in the UK dates back to 1995 and their introduction coincided with the medium-term effects of the silicone-implant controversy. We present a review of 3 years' experience of the Trilucent implant (1996-1998) during which 29 patients with a mean age of 39.4 years had a total of 50 implants. The aim of the study was to analyse the results in these patients in terms of complications, reoperation rate and patient satisfaction. Using a combination of retrospective chart analysis and postal survey, we found an incidence of implant deflation of 10% (5/50). The overall reoperation rate was 20% (10/50). The postal survey yielded a mean satisfaction score of 7.1 (on a scale of 0-10) from the 20 respondents out of the 29 patients (68.9%). In view of the high complication rate, we discontinued the use of Trilucent implants in advance of their withdrawal by the Medical Devices Agency (MDA) in March 1999. However, these findings may now be considered of added interest, particularly with regard to patients who are opting to keep their Trilucent implants despite the recommendation of the MDA in June 2000 that such implants should be removed.

Adult↗
PubMed1996

Kinetic analysis of glutamate transport by the miniswine choroid plexus in vitro.

Transport of glutamic acid by the choroid plexus, the blood-cerebrospinal fluid (CSF) barrier, was investigated by using the isolated choroid plexi from the fourth (FVCP) and lateral ventricles (LVCP) of the young adult miniswine in vitro. Glutamic acid uptake was very pronounced, with concentrations 7-fold (LVCP) and 2.4-fold (FVCP) higher in tissue than in medium after only 5 min of incubation with 1 microM glutamic acid. Tissue/medium ratios reached steady state by 15 min at 30-fold (LVCP) and 11-fold (FVCP). Uptake was energy-dependent and inhibited by ouabain and hypothermia. L-Aspartic acid was shown to be inhibitory in a concentration-dependent manner, suggesting that it shares a common transport system, whereas neither octanoic acid nor okadaic acid (transported by a separate fatty acid system) inhibited glutamic acid transport. At the same temperature, the labeled metabolite of glutamate (glutamine) in the tissue was 64.7%, 73.2%, and 72.5% of total radioactivity at 5, 30, and 60 min, respectively. The estimated Km values for glutamate uptake by the choroid plexus are 264 microM (FVCP) and 196 microM (LVCP); Vmax values are 87 (FVCP) and 147 (LVCP) nmol/g/min, respectively. These results indicate that, in addition to the metabolism of glutamate to glutamine, an active uptake mechanism is present in the choroid plexus of miniswine which may serve to regulate glutamic acid concentration in the CSF.

Animals↗
PubMed1994

Squamous cell carcinoma of the pinna: a 6-year study.

Over a 6-year period, 54 sequential lesions of squamous cell carcinoma of the pinna were studied in 44 patients with regard to the side, clinical features and their duration, TNM clinicopathological classification, treatment and follow-up. Treatment delay, types of surgical procedures, anaesthesia and postoperative complications were all analysed. The overall incidence of residual and recurrent cancer was 25.92%. The regional lymph node recurrence was 9.26%, though only 5.56% had clinically persistent cancer. Six patients subsequently died; two of these deaths were due to the cancer.

Aged↗
PubMed1994

An unusual cause of sunbed burns.

Three women successively using the same sunbed received superficial to medium partial thickness burns as a result of an ultraviolet filter slipping out of place. Whilst the longer-term effects of the various spectra of ultraviolet (UV) light continue to be evaluated, the near-immediate cutaneous and/or ocular sequelae of excess exposure are well known. Cutaneous burns are not, however, immediately manifest and it is concluded that suntanning devices should incorporate failsafe mechanisms activated by filter slippage or other malfunction.

Adult↗
PubMed1994

Body and organ growth of the developing Hormel-Hanford strain of male miniature swine.

As part of a larger study designed to characterize the early developmental stages of the Hormel-Hanford strain miniature pig, whole body, brain, kidney, liver, pancreas and spleen from male animals were examined for weight increases from one to 196 days, the approximate age of maturity. At 196 days, body weights had increased to 82.5 times the weight at day 1; increases in organ weights were greatest for spleen, less and similar for kidney, liver and pancreas, and the least for brain. Little change in relative organ weights was noted, except for the brain where an almost steady decrease occurred starting from 7 days after birth.

Animals↗
PubMed1994

Ornithine decarboxylase, fatty acid synthetase, and lipid levels in selected organs of the postnatal developing male miniature pig.

Ornithine decarboxylase (ODC) and fatty acid synthetase (FAS) activities were determined in tissues from male neonate and juvenile miniature swine (Hormel-Hanford strain) at various ages. ODC activity was measured in liver, brain, kidney, pancreas, and spleen at one day and at 1, 4, 8, 12 and between 24 and 32 weeks. Hepatic FAS activity, total lipid, triglyceride, and total cholesterol were measured at 2, 8, 16, and 32 weeks. Generally, tissue ODC activity was highest in the spleen at all ages. Three postnatal patterns of ODC activity were observed for the different organs. The mean values of FAS activity, total lipid, and cholesterol were highest at 8 weeks compared to other sampling periods.

Animals↗
PubMed1993

Prevention of heart disease by subcutaneous desferrioxamine in patients with thalassaemia major.

BACKGROUND: Cardiac siderosis from transfused iron remains the major cause of death in thalassaemia major, despite iron chelation therapy with desferrioxamine. AIMS: Our aim was to determine the nature and extent of cardiac involvement and its relationship to desferrioxamine use in a group with thalassaemia major. METHODS: We reviewed 76 patients with thalassaemia major and performed multiple logistic regression to analyse factors affecting cardiac involvement. Factors studied included: patient sex, age, haemoglobin, serum ferritin, total transfusions, liver iron, duration of desferrioxamine use, electrocardiograms, echocardiograms and compliance to desferrioxamine treatment. RESULTS: Thirty-seven patients developed heart disease. They were older (p < 0.001), began desferrioxamine later (p < 0.001), had more liver iron (p = 0.014), higher serum ferritin levels (p = 0.023) and received more blood (p = 0.018). Compared to those with optimal compliance the odds of developing heart disease were increased 10.7 times in fair compliers (p < 0.001) and 5.1 times in poor compliers (p = 0.016). However, there was no significant difference between those with fair and poor compliance. After multivariate analysis only compliance (p = 0.02) and age at desferrioxamine onset (p = 0.004) remained significant. Compliance was inversely related to liver iron (p < 0.001), serum ferritin (p < 0.001) and age at desferrioxamine commencement (p < 0.001). CONCLUSIONS: We conclude that late commencement of desferrioxamine and noncompliance are associated with greater iron loading and an increased risk of heart disease.

Adolescent↗
PubMed1991

The Coventry thermal injury study.

Two hundred and fifty-six consecutive new patients seen in the weekly burns outpatient clinic were questioned, concerning details of their injury and first aid measures taken, and the information was recorded on a questionnaire. Following computer analysis, an interesting pattern of incidence, susceptible age groups, 'danger zones', and first aid given in the community emerged. Conclusions regarding burn prevention and first aid have been drawn.

Adolescent↗
PubMed1988

Phalloplasty using the free radial forearm flap.

Our experience of phalloplasty using the radial forearm flap in five transsexual cases is reported. The results are disappointing due to the high incidence of complications. We had partial success in two cases, both complicated by a fistula, and complete failure in three cases due to vascular thrombosis.

Female↗