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Biomedical subjects

W Thompson

Publications and source records attributed to W Thompson.

At least 109 records · Page 6Linked to original sources
PubMed1988

Conventional dose intravenous pulsatile GnRH therapy does not induce ovulation in polycystic ovarian disease.

The value of pulsatile GnRH therapy for induction of ovulation in patients with polycystic ovarian disease remains unclear. Intravenous pulsatile GnRH therapy was administered to a defined group of 5 patients with polycystic ovarian disease; all were infertile, had an LH:FSH ratio of greater than 2:1 on two or more occasions, and had multiple cysts on ovarian ultrasonography. All had failed to respond to clomiphene citrate. The 5 patients received increasing doses of GnRH (5-40 micrograms/pulse) continuously for up to 6 weeks. The response was evaluated by serial hormone levels and ovarian ultrasonography. During nine treatment periods no patient ovulated, and in only one did the LH:FSH ratio revert to normal. Four patients have subsequently had wedge resection of the ovaries and in each case the diagnosis of polycystic ovarian disease was confirmed. Pulsatile GnRH therapy was of no value in the management of this group of infertile patients with strictly defined polycystic ovarian disease.

Adult↗
PubMed1987

Effect of induced leucocyte migration on mammary cell morphology and milk component biosynthesis.

Effects of increasing milk somatic cell count on milk composition, milk component biosynthesis, and quantitative mammary histology were studied following intramammary infusion of sterile oyster glycogen in lactating ewes. Oyster glycogen had no direct effect on mammary tissue utilization of radiolabeled acetate. Intramammary infusion of oyster glycogen following each of six consecutive milkings in six lactating ewes increased mean milk somatic cell count (6-fold) and increased percent fat and protein but decreased milk lactose concentration. Quantity of damaged or nonsecretory epithelial cells was increased. Infused glands had increased concentrations of neutrophils (3-fold) and plasma cells (1.3-fold) in the subepithelial stroma and of neutrophils (2.7-fold) within the epithelial lining of alveoli. Infusion of oyster glycogen every 3 d for 30 d in four ewes elicited similar changes in milk somatic cell count and mammary histology. Loss of functional mammary cells associated with leucocytosis may explain lost milk production associated with increased milk somatic cell count.

Animals↗
PubMed1987

LHRH analogue therapy in infertile women with luteal phase defects.

Management of patients with unexplained (ovulatory) infertility is a difficult clinical problem. Some of these women exhibit repetitive luteal phase defects which may or may not respond to conventional treatment with anti-oestrogens or progesterone supplementation. Ablation of the defective cycles, by rendering the patients hypogonadotrophic, and then substituting induced cycles using exogenous gonadotrophins, was employed in 10 women who had been inexplicably infertile for up to 14 years. Over a trial period of six cycles good luteal phase progesterone profiles were achieved in all instances, but only two term pregnancies occurred. A further two patients conceived but one aborted and one had a tubal pregnancy. The results are discussed critically, regarding the importance of luteal phase defects in the aetiology of infertility and the conception rates which may occur even if no specific therapy is prescribed.

Adult↗
PubMed1986

Rapid accumulation of diacyl lipid in rat liver microsomes by selective acylation of 2-acyl-sn-glycero-3-phosphorylserine.

2-Acyl-sn-glycero-3-phosphoryl[U-14 C]serine (2-acylGPS) was prepared by digesting 1,2-dioleoyl-sn-glycero-3-phosphoryl[U-14C]serine, mixed with pig brain phosphatidylserine (PS), with Rhizopus arrhizus lipase. The labeled lysolipid was shown to be actively acylated by rat liver microsomes in the presence of acyl-CoA thioesters, with the formation of diacylPS. In experiments with unlabeled lysolipid and [14C]acyl-CoA thioesters, digestion of the products with pancreatic phospholipase A2 showed that the acyl groups had been incorporated almost exclusively at position-1. The acylation reactions were dependent on pH of the incubation medium, time of incubation, concentration of microsomal protein and of lysolipid and thioester substrates. With [14C]lysolipid there was a clear preference for long-chain saturated over unsaturated acyl group donors and highest acylation rates were recorded with stearoyl-CoA. Since stearate is the major fatty acid at position-1 of tissue PS, these findings suggest that deacylation-reacylation reactions may be of importance in regulating the fatty acid profile of this lipid. The observed rates of acylation of 2-acylGPS in vitro were high in relation to the endogenous level of PS in the microsomal membranes, and short-term incubations led to net synthesis of PS with a many-fold increase in its concentration. The question is raised whether this is a latent activity expressed under optimal assay conditions in vitro, conditions that may not obtain in a cell, or whether the high acylating potential is indicative of an important function for the addition, or turnover, of acyl groups at position-1 of the serine lipid.

Acyl Coenzyme A↗
PubMed1984

Pharmacokinetics of cimetidine in critically ill patients.

Cimetidine disposition was studied after rapid (1 min) intravenous infusion in eight critically ill patients aged between 20 years and 77 years; one patient was studied on two occasions. Cimetidine dose was 300 mg in seven patients and 400 mg in the remaining patient. Arterial plasma cimetidine concentrations at the end of the infusion were very high and ranged from approximately 15-35 mg/l. Pharmacokinetic parameters displayed wide interpatient variability (coefficients of variation of 30-50%) and significant relationships emerged between some of these parameters and certain patient characteristics. Most notable, total systemic plasma clearance of cimetidine was directly related to estimated creatinine clearance (p less than 0.01). This relationship might prove to be a useful method of individualizing cimetidine dosage in critically ill patients.

Adult↗
PubMed1984

Radiologic, endoscopic, and surgical considerations of melanoma metastatic to the gastrointestinal tract.

Malignant melanoma is the most common malignancy to metastasize to the gastrointestinal tract. In a retrospective computer-assisted data search of over 2500 patients with melanoma registered over the past 10 years, 110 patients have been identified to have premortem gastrointestinal metastatic disease (metastatic disease identified at least 6 months before death). The small intestine (35%), colon (14.5%), and stomach (7%) are the most common sites for metastases. Polypoid or ulcerating masses and intramucosal nodules are typical radiologic presentations for gastric and colonic lesions, while over 50% of the small bowel metastases are polypoid masses that many times act as leading points for intussusception. Endoscopic studies are helpful in the preoperative diagnosis of these lesions. In a subset of 38 patients with symptomatic small bowel metastatic disease, complete resections were performed in 26% of patients, with palliative bypasses being performed in 40%, despite the fact that over 50% of the patients had documented visceral metastasis in other body sites. The operative morbidity rate was 15% with no operative deaths. Ninety percent of patients gained relief of symptoms, and overall survival from the time of confirmed small bowel disease averaged 17.3 months, with a range of 6 months to 9 years. It would seem that patients with melanoma with gastrointestinal metastatic disease can benefit from aggressive radiologic and endoscopic procedures for diagnosis and staging. Only through surgical interventions for symptomatic gastrointestinal disease can the quality of life be improved and life expectancy be extended.

Colonic Neoplasms↗
PubMed1984

Does geographical location influence inflow requirements of the Bain breathing system?

A review of publications from various countries, using the Bain system with a fresh gas flow of 70 ml kg-1 min-1 and controlled ventilation, show a range of mean PaCO2 values between 36 and 43 mmHg. It was suggested that these differences could be related to the geographic location of the patient population studied. Anaesthetists from seven institutions in West Germany, England, Sweden, the United States, Australia and Canada collaborated in a preliminary study designed to find out whether these differences could be reduplicated. In 142 patients under a standard anaesthesia with controlled ventilation, PaCO2 values were determined 30 min after the fresh gas flows had been set. For 70 ml kg-1 min-1 the mean PaCO2 values ranged from 33 to 40 mmHg; for 100 ml kg-1 min-1 from 28 to 35 mmHg. Compared to the mean PaCO2 values from Canada, the results from Australia and the USA were not different and all at the lower end of this range; Sweden, West Germany and England reported significantly higher PaCO2 values. In the absence of any other obvious explanation, we suggest that patients in England and Northern Europe could have a higher CO2 output under anaesthesia than North American or Australian patients.

Adult↗
PubMed1983

Synapse elimination in neonatal rat muscle is sensitive to pattern of muscle use.

The synaptic connections among the cells of the vertebrate nervous system undergo extensive rearrangements early in development. During their initial growth, neurones apparently form synaptic connections with an excessive number of targets, later retracting a portion of these synapses in establishing the adult neural circuits. Because of the profound effects which experience has upon the developing nervous system, a question of considerable interest has been the role which the functional use of these developing synapses might play in determining the final pattern of connectivity. At the neuromuscular junction the early changes in synaptic connections are well documented, and here questions about the importance of function can be relatively easily addressed. Mammalian skeletal muscle fibres experience a perinatal period of synapse elimination so that all but one of several synapses formed on each muscle fibre are lost. This synapse elimination is sensitive to alterations of neuromuscular use or activity. Reduction of muscle use by tenotomy or by paralysis of the muscle with drugs blocking nerve impulse conduction or neuromuscular transmission delays or even prevents synapse loss, while increased use produced by stimulation of the muscle nerve apparently accelerates the rate at which synapses are lost. I report here a further examination of the role of neuromuscular activity in synapse elimination. I show that chronic neuromuscular stimulation accelerates synapse elimination but that this acceleration is dependent on the temporal pattern in which the stimuli are presented: brief stimulus trains containing 100 Hz bursts of stimuli produce this acceleration whereas the same number of stimuli presented continuously at 1 Hz do not. Furthermore, the 100 Hz activity pattern which is effective in altering synapse elimination also alters two other muscle properties: the sensitivity of the muscle fibers to acetylcholine and the 'speed' of muscle contractions. These findings suggest that the ability of muscle fibres to maintain more than one nerve terminal, like other muscle properties, is sensitive to the pattern of muscle use rather than just the total amount of use.

Acetylcholine↗
PubMed1983

Cystic hygroma simulating an encephalocele.

An ultrasound examination at 17 weeks gestation on a woman with a family history of spina bifida suggested that the fetus had a closed encephalocele. Amniotic fluid alphafetoprotein, rapidly adhering cells and acetylcholinesterase gel electrophoresis were normal. The pregnancy was terminated and the fetus was found to have a large cystic hygroma. It is suggested that in counselling parents of an infant or fetus with a cystic hygroma and with a normal chromosome constitution, ultrasound examination in future pregnancies is advisable, because of the possibility of autosomal recessive inheritance.

Adult↗
PubMed1982

Counselling patients for artificial insemination and subsequent pregnancy.

Patients contemplating conception by artificial insemination can be assured that their pregnancy will be as normal as that following natural insemination. In particular, there is no evidence of increased rate of abortion or fetal abnormality. In general, the results of AIH are disappointing and patients should be made aware of this before such treatment is advised or undertaken. The indications must be well defined and a realistic prognosis given. Pregnancy rates with AID are good using either fresh or frozen semen. It is the moral and legal implications of this procedure which raise the problems. Therefore it is vital that a couple be allowed to consider these problems fully before proceeding and it is the responsibility of their medical practitioner to ensure that they have the facility to do this.

Counseling↗