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Biomedical subjects

G R Thompson

Publications and source records attributed to G R Thompson.

At least 91 records · Page 5Linked to original sources
PubMed1991

Methotrexate injection of tubal ectopic pregnancy. A logical evolution?

OBJECTIVE: To test the efficacy and possible side effects of a single 20 mg dose of methotrexate injected at the time of laparoscopy, in the treatment of tubal ectopic pregnancy. DESIGN: The study was a non-randomised non-blinded prospective clinical trial. SETTING: The study was carried out at two tertiary referral hospitals. PATIENTS: Eighteen patients with unruptured tubal ectopic pregnancies and in a stable haemodynamic condition were offered entry into the study and all of these agreed. INTERVENTIONS: At diagnostic laparoscopy, 20 mg of methotrexate in 0.8 mL was injected by fine needle in or around the ectopic gestation. MAIN OUTCOME: Patients were followed up as outpatients by serial blood tests until resolution of the ectopic pregnancy was demonstrated by a return of the level of beta-human chorionic gonadotrophin to the normal range. RESULTS: There was one failure of treatment. The ectopic pregnancy resolved in the remaining 17 patients. There were no side effects attributable to methotrexate and tubal patency was demonstrated in the eight patients tested by hysterosalpingography.

Adult↗
PubMed1991

Cholesterol flux in cholesterol ester-loaded macrophages in an in vitro perfusion system.

Cholesterol ester-loaded J774 macrophages attached to microcarrier beads were perfused or incubated with lipoproteins in vitro. Cholesterol influx was reduced by decreasing LDL cholesterol, efflux was promoted by increasing HDL cholesterol or by adding apolipoprotein A-I/phosphatidylcholine complexes to the perfusate or incubation medium. Addition of sera obtained from patients after LDL apheresis or plasma exchange resulted in much smaller increments in cell cholesterol than pretreatment sera, due to decreased influx, but efflux was unchanged despite the reduction in HDL cholesterol by plasma exchange. These data suggest that extracorporeal cholesterol removal promotes mobilization of intracellular cholesterol ester mainly by reducing cholesterol influx.

Animals↗
PubMed1991

Response to cholesterol-lowering drugs in familial defective apolipoprotein B-100.

The effect of cholestyramine and simvastatin, given separately or in combination, on serum lipid concentrations in 11 patients with heterozygous familial defective apolipoprotein B-100 was compared with that in 11 matched patients with heterozygous familial hypercholesterolaemia. In both groups of patients there was a substantial fall in serum lipid levels in response to treatment. There were no significant differences between the reductions in serum total or low-density lipoprotein cholesterol levels in the two groups.

Adult↗
PubMed1991

Relationship of immunosuppression and serum lipids to the development of coronary arterial disease in the transplanted heart.

Coronary arterial disease in the cardiac allograft has emerged as the most serious long term complication of cardiac transplantation. The influence of patient-related and other potential risk factors on the development of coronary arterial disease at 1 year subsequent to cardiac transplantation was examined in 207 recipients. The mean age of donors in patients with coronary arterial disease was 28.5 +/- 9.5 years, compared to 22.6 +/- 7.9 years in patients without coronary arterial disease (P less than 0.01). Eight of the 35 patients who received immunosuppression by means of prednisone and azathioprine developed coronary arterial disease compared to 5 of the 172 patients who were treated with cyclosporin and azathioprine without routine oral prednisone (P less than 0.01). The relationship of levels of serum lipids to the subsequent development of coronary arterial disease was investigated in 95 patients with angiographically normal coronary arteries one year after cardiac transplantation. The cumulative probability of coronary arterial disease in those with total cholesterol greater than 5.8 mmol/l was 9.3% at 2 years (n = 40), 24.4% at 4 years (n = 21) and 45% at 4 years (n = 9) compared with 4.3% at 2 years (n = 45), 7.4% at 3 years (n = 32) and 14% at 4 years (n = 14) in those with a total cholesterol less than 5.8 mmol/l (P less than 0.05). Similarly, the incidence of coronary arterial disease was increased in patients with serum triglyceride greater than 1.4 mmol/l (P less than 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Quantitation of plasma mevalonic acid using gas chromatography-electron capture mass spectrometry.

Circulating concentrations of mevalonic acid (MVA) change in parallel with, and may be used as a marker of cholesterol biosynthesis. Plasma MVA levels have been quantified using a sensitive and specific capillary gas chromatography-electron capture mass spectrometric assay. The detection limit for MVA in plasma is 100 pg/ml; the intra-assay variation is 5.11%; the inter-assay variation is 7.7%. Using this assay, the mean plasma MVA in 15 normolipidemic subjects was 2.37 +/- 1.2 ng/ml (range 0.41-5.31 ng/ml). Administration of 40 mg of simvastatin (an HMG-CoA reductase inhibitor) significantly accenutated the diurnal decrease in plasma MVA levels. This assay may be useful in investigating cholesterol synthesis rates in different dyslipidemias and individual responses of HMG-CoA reductase-inhibiting drugs.

Adolescent↗
PubMed1991

Expression of IL-2 receptor p55 and p75 chains by human B lymphocytes: effects of activation and differentiation.

Whilst B cells in human blood can be shown to express interleukin-2 receptor (IL-2R) p55 and p75 chains, using a high-sensitivity immunofluorescence procedure, fresh tonsil B cells did not show detectable levels of expression. Culture of tonsil B cells led to low levels of expression of the p55 chain of the IL-2R, an effect which was dependent on protein synthesis. The level of expression of IL-2R chains could be modulated by culturing in the presence of a number of factors which activate B cells. p55 levels were more readily modulated than p75 levels. IL-4 and combinations of IL-4 with anti-IgM, IL-2 or tumour necrosis factor-beta (TNF-beta) modulated p55 levels, but IL-5 did not. Changes in IL-2R expression were small when compared with other B-cell activation markers such as CD23. When unfractionated tonsil cells were activated with a polyclonal stimulus, the major change was the expression of p55 by T-cell blasts--p75 expression remained low in T and B cells, and p55 expression by B cells remained low.

B-Lymphocytes↗
PubMed1990

Relation of serum lipoprotein(a) concentration and apolipoprotein(a) phenotype to coronary heart disease in patients with familial hypercholesterolemia.

Familial hypercholesterolemia carries a marked increase in the risk of coronary heart disease (CHD), but there is considerable variation between individuals in susceptibility to CHD. To investigate the possible role of lipoprotein(a) as a risk factor for CHD, we studied the association between serum lipoprotein(a) levels, genetic types of apolipoprotein(a) (which influence lipoprotein(a) levels), and CHD in 115 patients with heterozygous familial hypercholesterolemia. The median lipoprotein(a) level in the 54 patients with CHD was 57 mg per deciliter, which is significantly higher than the corresponding value of 18 mg per deciliter in the 61 patients without CHD. According to discriminant-function analysis, the lipoprotein(a) level was the best discriminator between the two groups (as compared with all other lipid and lipoprotein levels, age, sex, and smoking status). Phenotyping for apolipoprotein(a) was performed in 109 patients. The frequencies of the apolipoprotein(a) phenotypes and alleles differed significantly between the patients with and those without CHD. The allele LpS2, which is associated with high lipoprotein(a) levels, was found more frequently among the patients with CHD (0.33 vs. 0.12). In contrast, the LpS4 allele, which is associated with low lipoprotein(a) levels, was more frequent among those without CHD (0.27 vs. 0.15). We conclude that an elevated level of lipoprotein(a) is a strong risk factor for CHD in patients with familial hypercholesterolemia, and the increase in risk is independent of age, sex, smoking status, and serum levels of total cholesterol, triglyceride, or high-density lipoprotein cholesterol. The higher level of lipoprotein(a) observed in the patients with CHD is the result of genetic influence.

Adult↗
PubMed1990

Primary hyperlipidaemia.

It is estimated that over 60% of the variability in serum lipids is genetically determined, most of this variation being due to polygenic influences. Interaction between the latter and environmental factors is probably the commonest cause of hyperlipidaemia in the general population. Familial forms of hyperlipidaemia are usually more clearly defined, especially those which have a monogenic or dominant pattern of inheritance, but are less common. This type of disorder, exemplified by familial hypercholesterolaemia, is expressed independently of environmental influences. In contrast, in familial type III hyperlipoproteinaemia inheritance of the underlying gene defect is often insufficient to produce hyperlipidaemia unless additional environmental or genetic influences coexist. Rarely, hyperlipidaemia is recessively inherited, as in familial deficiency of lipoprotein lipase and of apolipoprotein CII. Primary hyperlipidaemias characterized by severe hypertriglyceridaemia predispose to acute pancreatitis whereas those disorders characterized by hypercholesterolaemia, apart from hyper alpha lipoproteinaemia, are associated with an increased risk of premature vascular disease.

Female↗
PubMed1990

CO2 laser laparoscopic salpingotomy for treatment of tubal ectopic pregnancies: potential limitations.

Linear salpingotomy was performed on 16 patients using the CO2 laser laparoscopically directed. Median operating time was 60 minutes (range 40-100) and all patients were discharged on the first postoperative day. There were 4 patients in whom persistence of trophoblast activity was detected, 2 of whom were treated surgically and 2 by oral methotrexate therapy. Conservative techniques for the treatment of ectopic pregnancy have proliferated since 1953 being made possible because of the early presentation of patients and the more sensitive methods of intrauterine pregnancy detection. In the past decade laser technology has been added to the armamentarium of infertility surgeons and there have been 2 reports of its successful use in cases of ectopic pregnancy. The present study aimed to examine the application of this technique in our patient population and to investigate any associated problems.

Adult↗
PubMed1990

Towards a new era: is coronary artery disease reversible?

There is increasing evidence that conventional lipid-lowering therapy can arrest the progression of coronary atherosclerosis. Trials are now under way to determine whether more radical reduction of low-density-lipoprotein cholesterol will reverse atherosclerosis and lead to regression of coronary lesions. The ability to effect such reductions has been markedly enhanced by the introduction into clinical practice of the 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibitors.

Cholesterol, HDL↗
PubMed1990

HMG CoA reductase inhibitors as lipid-lowering agents: five years experience with lovastatin and an appraisal of simvastatin and pravastatin.

The HMG CoA reductase inhibitors are the most effective drugs for treating hypercholesterolaemia currently available. They inhibit cholesterol synthesis and thus stimulate receptor-mediated uptake and degradation of low-density lipoprotein cholesterol by the liver. In 30 patients with severe hypercholesterolaemia administration of lovastatin alone or in combination with other lipid-lowering manoeuvres maintained reductions of 25 to 31 per cent in serum cholesterol over five years. The drug was easy to take and well tolerated, the only significant side effect being a reversible myopathy. Two similar compounds, simvastatin and pravastatin, exert comparable effects on serum lipids, including modest reductions in triglycerides and increases in high-density lipoprotein cholesterol. The use of these drugs seems likely to exert a beneficial effect on atherosclerosis.

Adult↗