Search PubMed⌕ Search

Biomedical subjects

R Thomas

Publications and source records attributed to R Thomas.

At least 451 records · Page 25Linked to original sources
PubMed1993

Pneumothorax and palliative pleural aspiration--an audit of technique.

The incidence of pneumothorax following a review of 55 single-sitting bedside pleural aspirations of malignant effusions over an 18-month period in the clinical oncology departments of the Middlesex and Mount Vernon Hospitals was assessed and two groups were compared. Group 1 (29 aspirations in 16 patients) involved a technique using an 8 ch (French) gauge trocar and cannula, a three-way tap and a sealed bag system, resulting in no pneumothoraces. Group 2 (26 aspirations in 18 patients) involved a variety of other techniques with a pneumothorax rate of 19.2% (p = 0.0189 using Fisher's Exact Test). The small trocar/sealed bag system was complication-free, relatively painless, quick to perform, cheap, gave the option of draining to dryness and was easily learnt by the junior doctors who most often perform this procedure at the bedside. This technique is described in detail in the text. A reduction in the risk of pneumothorax minimizes the need for a postaspiration chest radiograph, facilitating aspiration in an outpatient, hospice or domiciliary setting. A domiciliary study is to be planned using the procedural standard described.

Chest Tubes↗
PubMed1993

Changes in the radiation treatment of cancer of the anus in Glasgow.

The survival and complication rate of two groups of patients with carcinoma of anus were compared. The first group of 20 patients were treated between 1974 and 1983 by double plane implantation using radium or equivalent caesium needles and supplementary external beam radiotherapy to groin nodes if present. The second group of 26 patients were treated between 1984 and 1990 by external beam radiotherapy followed by a jig implant using afterloading iridium needles. 5-year survival was superior in the second group (73% vs. 40%) with a lower incidence of radiation-induced complications.

Adenocarcinoma↗
PubMed1993

Effects of dietary fibre on faecal steroid measurements in baboons (Papio cynocephalus cynocephalus).

A study was conducted in captive baboons to determine (i) the impact of cereal dietary fibre on faecal progestogen excretion, and (ii) whether means of controlling dietary effects could be identified. Blood was collected on 3 days per week and faeces on 5 days per week from four unanesthetized cyclic female baboons, consecutively fed three diets of 5, 10 and 20% fibre for 90 days per diet. A 2 day lag time was detected before progesterone in the blood appeared in the faeces, regardless of diet (mean correlation was 0.62, P = 0.002). Increased dietary fibre had a negative effect on progestogen excretion (P < 0.004). Correspondence between blood and faecal progestogens was consistently greatest and the effect of dietary fibre least when faecal progestogens were expressed g-1 dry faeces. Several means of indexing faecal steroid excretion rates were examined including dehydroepiandrosterone (DHEA) and a number of byproducts of cholesterol metabolism. The cholesterol metabolite, cholestanone, was positively correlated with dietary fibre (r = 0.27; P < 0.04). Multiplying faecal progestogen concentration by the cholestanone g-1 dry faeces concentration increased the correlation between serum and cholestanone-indexed faecal progestogens (r = 0.78, P = 0.0001) compared with nonindexed progestogens (r = 0.71, P = 0.0001). We conclude that expressing faecal progestogens g-1 dry faeces may be sufficient and the most cost-effective method for controlling for most dietary effects when the objective is monitoring longitudinal endocrine status in baboons. However, it may be appropriate to express faecal progestogens by cholestanone concentrations when increased precision is needed to overcome the effects of profound variations in dietary fibre.

Animals↗
PubMed1993

Cost effectiveness of beractant in the prevention of respiratory distress syndrome.

Beractant, a modified natural bovine surfactant extract, has been used successfully in the prevention of respiratory distress syndrome (RDS) in premature neonates. This analysis investigates the cost effectiveness of prophylactic surfactant therapy. Resource utilisation data were analysed retrospectively from 210 patients who had participated previously in a double-blind, placebo-controlled clinical trial. No baseline differences were apparent between the beractant and sham-air control groups. There was a significant difference in survival favouring the beractant-treated neonates. When the acquisition cost of the study drug was excluded, there was an incremental, daily cost-savings benefit for the beractant-treated group compared with the sham-air treated group. Costs per case per day were significantly lower for neonates treated with beractant ($US1442 beractant vs $US1544 sham-air; 1991 dollars p = 0.01). Costs for radiological and diagnostic procedures, respiratory care and drugs (excluding beractant) were all significantly lower. When the acquisition cost of beractant was included, the cost to produce a 28-day survivor was $US3319 less with beractant ($US41 020) than with sham-air ($US44 339). Thus, when viewed in terms of costs per year of life saved, beractant compares very favourably with other recently evaluated health technologies.

Cost-Benefit Analysis↗
PubMed1993

An in vitro protocol for evaluation and comparison of membrane oxygenators.

With the trend in open heart surgery toward normothermic bypass and warm blood cardioplegia, greater demand is being placed on the perfusionist to select an oxygenator that will perform safely and efficiently under a variety of conditions. While manufacturers report performance parameters for their products, the data is often not comparable due to widely differing conditions. Recent in vitro evaluation techniques employed to characterize membrane oxygenators do not simulate the actual oxygenator conditions observed during cardiopulmonary bypass. Biocompatibility and drug delivery are reported but comparisons of different oxygenator performance parameters are not completely addressed. We have designed a test circuit and an evaluation protocol to simultaneously characterize the performance of multiple oxygenators under identical conditions. The test circuit is designed to simulate clinical conditions and to evaluate gas exchange, blood path pressures, gas path pressures, and hemolysis. Previously reported studies have relied on a comparison of a single membrane oxygenator and a single bubble oxygenator. Our protocol will compare multiple membrane oxygenators, in vitro, under similar clinically relevant conditions. Such testing would be done prior to animal or clinical trials. Furthermore in vitro tests should be more reproducible and more discriminating than are ex vivo tests.

Equipment Design↗
PubMed1993

Antibody detection errors due to acidic or unbuffered saline.

Isotonic saline solutions, buffered with potassium phosphate or sodium phosphate salts, were evaluated in parallel with unbuffered saline to determine if they improved antibody detection by solid phase red cell adherence or hemagglutination methods. Saline buffered to a pH of 7.0 to 7.5, when used to suspend red cells or to wash sensitized red cells in preparation for the antiglobulin test, produced the best positive solid phase and hemagglutination results. The pH range of commercially prepared blood bank saline (unbuffered) was found to be 5.8 to 6.8, far lower than the desired pH for optimum antibody detection. In the case of solid phase assays employing intact, immobilized reagent red cells, saline with a pH of 7.0 to 7.5 also eliminated falsely positive results due to the dissociation of red cell monolayers from the solid support surface that occurred in the presence of unbuffered or acidic saline. These findings indicate that unbuffered isotonic saline should not be used in solid phase- or hemagglutination-based antibody detection tests. It is recommended that phosphate-buffered saline at a pH of 7.0 to 7.5 be employed.

Journal Article↗
PubMed1993

Tryptophan and 5-hydroxytryptamine metabolism in alcoholism.

Alcohol (ethanol) exerts a variety of effects on tryptophan (Trp) and 5-hydroxytryptamine (5-HT, serotonin) metabolism in man and experimental animals. In human healthy volunteers, acute ethanol consumption lowers circulating Trp availability to the brain, almost certainly leading to inhibition of cerebral 5-HT synthesis, possibly by enhancing liver Trp pyrrolase activity. In non-abstinent chronic alcoholics, however, Trp pyrrolase activity may be inhibited; here acute ethanol intake fails to lower circulating Trp concentration. Hepatic Trp degradation seems to be greater during abstinence, and chronic alcoholics then exhibit a decrease in Trp availability to the brain. It is, however, not clear whether this decrease and the likely associated higher liver Trp pyrrolase activity in abstinence are due to previous long-term alcohol consumption, or are inherent biological determinants of the low brain 5-HT in alcoholism. The latter possibility is supported by the recent implication of the Trp pyrrolase gene in alcoholism. In alcohol-preferring C57BL mice, the low brain [5-HT] is due to a higher liver Trp pyrrolase activity associated with a higher circulating [corticosterone]. Activity or expression of liver Trp pyrrolase and/or their induction by glucocorticoids may be important biological determinants of predisposition to alcohol consumption, and further work in this area may therefore be fruitful.

Alcoholism↗
PubMed1993

Incidence of complications following 5-fluorouracil with trabeculectomies.

To investigate the incidence of complications reportedly caused by the use of 5-fluorouracil (5-FU) in glaucoma filtering surgery, we performed trabeculectomy with 5-FU on 57 eyes of 56 patients with advanced glaucoma. The mean preoperative intraocular pressure was 34.8 mm Hg. The most frequent complication encountered was superficial punctate keratopathy (26%), followed by shallowing of the anterior chamber (12%), choroidal detachment (9%), and flap retraction (7%). We, however, did not encounter any cases of confluent corneal epithelial defect, subepithelial scarring, or striate melanokeratosis which are usually described with the use of 5-FU. With a mean follow-up of 7.1 months, an intraocular pressure less than 16 mm Hg without hypotensive therapy were achieved in 73.7% of cases, and less than 21 mm Hg without hypotensive therapy in 86%. Considering the low incidence of complications and the high success rate, we recommend the use of 5-FU in routine glaucoma filtering surgery.

Combined Modality Therapy↗
PubMed1993

Botulinum toxin in the treatment of paralytic strabismus and essential blepharospasm.

As an alternative to conventional medical and surgical modalities that have met little success in the treatment of paralytic strabismus and essential blepharospasm, we explored the use of botulinum toxin as a treatment of choice in these two disorders. We used botulinum toxin in three patients with paralytic strabismus and in nine patients with essential blepharospasm. In three patients with paralytic strabismus, the botulinum toxin was injected into the ipsilateral antagonist of the paralysed muscle. The preinjection deviations ranged from 18 to 60 prism diopters. Two of these three patients achieved orthotropia around the thirtieth day and thereafter maintained it. The third patient became orthotropic on the eighteenth day, but deviation recurred and therefore required another injection of toxin. In nine patients with essential blepharospasm, botulinum toxin was injected into the orbicularis oculi muscles. Both objective and subjective improvement occurred in all nine patients within seven days and the effect lasted 12 to 15 weeks. Further injection of the toxin produced extremely beneficial results. However, the only significant complication that we encountered in both groups of strabismus and blepharospasm was ptosis, which was usually partial and temporary. From our experience, we advocate the use of botulinum toxin in the treatment of essential blepharospasm.

Adult↗
PubMed1993

Anterior capsular support for posterior chamber intraocular lenses following vitreous loss in endocapsular surgery.

We used anterior capsular support for posterior chamber intraocular lenses (PC IOLs) in fourteen eyes with large posterior capsular ruptures. An endocapsular technique preserved the anterior capsule and facilitated implantation. With a median follow up of 8.5 months, all patients had a visual acuity of 6/9 or better. One lens was lost in the vitreous and one patient had a clinically significant cystoid macular edema. In the event of a posterior capsular rupture we suggest this technique as an alternative to anterior chamber or scleral-fixated lenses.

Adolescent↗
PubMed1993

Releasable suture technique for trabeculectomy.

We studied the effect of the releasable suture technique on immediate postoperative intraocular pressure (IOP). Nine eyes of nine patients with glaucoma had trabeculectomy with a releasable suture. In the six eyes that did not receive antimitotics, the suture was released by the fifth postoperative day; in the others suture release was delayed up to the fourteenth day. Of the nine patients, one had an acceptable postoperative IOP and did not need suture release; in another the suture broke and could not be released. In the remaining seven patients, the difference between the pre-release and post-release IOP was statistically significant (p < 0.001). The complications of this technique include failed suture release, subconjunctival hematoma and a distinctive "windshield wiper" keratopathy.

Corneal Diseases↗
PubMed1993

Dry-land resistance training for competitive swimming.

To determine the value of dry-land resistance training on front crawl swimming performance, two groups of 12 intercollegiate male swimmers were equated based upon preswimming performance, swim power values, and stroke specialties. Throughout the 14 wk of their competitive swimming season, both swim training group (SWIM, N = 12) and combined swim and resistance training group (COMBO, N = 12) swam together 6 d a week. In addition, the COMBO engaged in a 8-wk resistance training program 3 d a week. The resistance training was intended to simulate the muscle and swimming actions employed during front crawl swimming. Both COMBO and SWIM had significant (P < 0.05) but similar power gains as measured on the biokinetic swim bench and during a tethered swim over the 14-wk period. No change in distance per stroke was observed throughout the course of this investigation. No significant differences were found between the groups in any of the swim power and swimming performance tests. In this investigation, dry-land resistance training did not improve swimming performance despite the fact that the COMBO was able to increase the resistance used during strength training by 25-35%. The lack of a positive transfer between dry-land strength gains and swimming propulsive force may be due to the specificity of training.

Adult↗
PubMed1993

Association between epidural analgesia during labor and fever.

BACKGROUND: Epidural analgesia has been associated in previous research with an increase in maternal temperature. METHODS: Three studies were done: a retrospective chart review of women in labor, a prospective cohort study of women in labor, and a case-control study of newborns with fever. The prospective study enrolled 28 women, 14 of whom received epidural analgesia. Maternal temperature was measured hourly with a tympanic membrane thermometer. Other variables examined included duration of labor, duration of ruptured membranes, and room temperature. To further explore the possible association between maternal epidural exposure and newborn fever, a case-control study of newborns with fever at birth was carried out. RESULTS: In both the retrospective and prospective studies of women in labor, the duration of epidural analgesia was correlated with maximum maternal temperature during labor, with an increase, in the prospective study, of 0.07 degrees C per hour of exposure to epidural analgesia (P = .002). Controlling for other variables did not change the magnitude of this effect or its statistical significance. Similar trends were seen in the newborn's first temperature in both the prospective study of women in labor and the case-control study of newborns, but the associations were not significant (P = .07 and .08, respectively). CONCLUSIONS: Epidural analgesia is associated with an increase in maternal temperature during labor and possibly with an elevation of newborns' first temperatures.

Analgesia, Epidural↗