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Biomedical subjects

R Thomas

Publications and source records attributed to R Thomas.

At least 523 records · Page 29Linked to original sources
PubMed1989

Risk factors, time course and treatment effect for restenosis after successful percutaneous transluminal coronary angioplasty of chronic total occlusion.

Advances in technology and operator experience, and increased use of angiography early after myocardial infarction have led to greater use of percutaneous transluminal coronary angioplasty (PTCA) for chronic, total coronary artery occlusions. To better assess long-term outcome, 257 consecutive patients with successful PTCA of a total occlusion with late angiographic follow-up from 484 patients (53%) with PTCA success were reviewed. The mean +/- standard deviation patient age was 54 +/- 10 years, 79% were men, the duration of total occlusion was 11 +/- 15 weeks and the post-PTCA diameter stenosis was 24 +/- 12%. Eighty-two, 27 and 63% of patients received long-term aspirin, dipyridamole and warfarin therapy, respectively. Angiography at 8 +/- 8 months demonstrated restenosis (greater than or equal to 50% diameter stenosis) in 41% of patients restudied within 6 months and in 66% of patients restudied within 12 months by life table analysis. In multivariate regression analysis of 19 variables, 2 were independently correlated with the occurrence of restenosis: post-PTCA diameter stenosis greater than 30% (p = 0.02) and coronary artery dilated (left anterior descending and right coronary arteries greater than the left circumflex coronary artery) (p = 0.05). In log rank analysis that also considered the timing of angiographic detection of restenosis, dilatation of a proximal left anterior descending stenosis was also a significant predictor of restenosis (p = 0.01), and dilatation within 4 weeks of the presumed time of occlusion was only weakly predictive (p = 0.11).(ABSTRACT TRUNCATED AT 250 WORDS)

Angioplasty, Balloon↗
PubMed1989

Growth hormone responses to growth hormone releasing factor in primary degenerative dementia.

The growth hormone (GH), thyroid-stimulating hormone (TSH), and prolactin (PRL) responses to growth hormone releasing factor (GRF) were investigated in 18 patients suffering from primary degenerative dementia (PDD) and in 20 age- and sex-matched normal elderly controls. There was no significant difference in the growth hormone response to GRF stimulation between patients and controls, and in neither subject group was there a demonstrable TSH or prolactin response to GRF. These findings indicate that the pathophysiology underlying the blunted growth hormone response to pharmacological challenge in PDD must lie at a suprapituitary level.

Aged↗
PubMed1989

An improvised mould for vaginoplasty.

The use of a simple, improvised mould for vaginoplasty is described. It is made of rubber foam rolled over a winged infusion cannula and covered over by condoms. It offers a number of advantages over conventional moulds, the main ones being its simplicity of construction and its ease of application and removal from the neo-vagina.

Catheterization↗
PubMed1989

The fate of radioiodinated endothelin-1 and endothelin-3 in the rat.

Endothelin-1 (ET-1) has been isolated from cultured endothelial cells and might have a role in cardiovascular regulation. To study the fate of labeled ET-1, we prepared [125I]-labeled ET-1 (formerly porcine and human ET) and ET-3 (formerly rat ET). Approximately 0.2 microCi (0.2 pmol) was injected into the left ventricle of anesthetized rats and blood samples analyzed for radioactivity for up to 40 min. The animals were then killed and the distribution of radioactivity determined in various organs. Both ET-1 and ET-3 were rapidly removed from the circulation, with more than 60% of the removal occurring in the first minute. Removal of ET-1 was somewhat faster than that of ET-3. The highest uptake of radioactivity was seen in lung, kidney, and liver. When ET-1 was infused into the isolated perfused lung of the guinea pig, 64 +/- 1.9% of the label was retained. Subcellular fractionation of the lung homogenate following infusion of labeled ET-1 showed that 93% of the label was associated with membranes and intracellular organelles, suggesting internalization of the bound ET-1. Together, the results indicate a high density of ET-1 binding sites in the lung, liver, and kidney and that these organs may be important in removing circulating ET-1.

Animals↗
PubMed1989

Detection of cardiac allograft rejection and myocyte necrosis by monoclonal antibody to cardiac myosin.

Indium 111-labeled monoclonal antibody to cardiac myosin was examined for efficacy in the detection of cardiac graft rejection and rejection-related myocyte necrosis. Heterotopic heart transplants were performed in isogenic and allogenic groups of rats (n = 56). At selected intervals posttransplant, uptake of injected antibody in the donor and native hearts was determined by gamma scintillation scanning. Indium uptake was compared to histologic results graded for the severity of rejection and the presence of myocyte necrosis. The donor heart uptake of labeled antibody was significantly greater in both moderate rejection and severe rejection than in lesser degrees of rejection (P = 0.05). The donor/native heart antibody uptake ratio (AUR) in both severe and moderate rejection were significantly different from no or mild rejection (P = 0.05). In pooled grafts without myocyte necrosis, both the absolute donor heart antibody uptake and the donor/native heart AUR were significantly greater in grafts with moderate or severe rejection than in those with no or mild rejection (P less than 0.001). Among grafts with moderate or severe rejection, those with myocyte necrosis had greater donor heart antibody uptakes and greater donor/native heart AUR than grafts without myocyte necrosis (P less than 0.001). The grade of rejection and the presence of histologic myocyte necrosis appear to be closely related but independent variables, both of which influence antibody uptake. It is concluded that monoclonal antibody to cardiac myosin may be a useful noninvasive tool that could distinguish moderate or severe rejection from lesser degrees of rejection and that could detect the presence of myocyte necrosis.

Animals↗
PubMed1989

Postural drainage in the management of postoperative hyphaema.

We describe the technique of postural drainage of hyphaemas following trabeculectomy alone or when combined with lens extraction and intraocular lens implantation. This technique helps avoid surgical intervention and seems to have no short-term deleterious effect on bleb function.

Cataract Extraction↗
PubMed1989

The place of trabeculectomy in the management of primary open-angle glaucoma and factors favouring success.

Medical treatment has always been the mainstay in the management of primary open-angle glaucoma (POAG). Surgical intervention has been reserved for cases with intraocular pressures uncontrolled on medical therapy and/or progression of visual field loss. Following the introduction of trabeculectomy, there was a move toward earlier surgery in POAG with some advocating it as a primary procedure. However, others have emphasised the complications and unpredictability of trabeculectomy and use it only as a last resort. In this article the literature is reviewed and the factors that prevent complications and help ensure a successful result in trabeculectomy are considered. While the role of trabeculectomy as a primary procedure in POAG is debatable, the authors favour earlier surgical intervention rather than using surgery as a last resort.

Glaucoma, Open-Angle↗
PubMed1989

Transient corneal changes associated with the use of gold foil electrodes.

The corneas of 50 normal subjects were examined before and after electroretinography performed with gold foil electrodes. Examination included slit-lamp biomicroscopy and staining with sodium fluorescein. All corneas were normal on examination prior to electroretinography. Three types of transient corneal changes were observed--punctate epithelial keratitis, corneal erosions, and stromal thinning. Each cornea was assigned a numerical damage score based on a simple scoring system. Thirty one subjects (62%) had some degree of corneal change, and in three cases (6%) follow-up was required. Multiple regression analysis was performed to discover any risk factors. Both age of the subject and the use of local anaesthetic were strongly associated with corneal changes.

Adult↗
PubMed1989

'In-the-bag' hyphaema--a rare complication of posterior chamber lens implantation.

A 72-year-old woman developed a hyphaema on the first postoperative day after a combined trabeculectomy and extracapsular cataract extraction with posterior chamber intraocular lens implantation. On the second day the blood had redistributed to accumulate 'in the bag' posterior to the intraocular lens and had formed a fluid level. Postural drainage helped to clear the hyphaema from both locations, with no short-term effect on visual function or the filtering bleb.

Aged↗
PubMed1989

The hormonal environment of post-natal depression.

The incidence of post-natal depression is high, and dramatic changes in steroid hormones and prolactin occur in the post-partum period. In an attempt to correlate these events, 147 mothers, six to eight weeks after delivery of a healthy infant, completed standard psychological tests, including the Edinburgh, Montgomery-Asberg, and Raskin scales. They also provided matched samples of plasma for assay of cortisol, oestradiol, progesterone and prolactin, and saliva for assay of cortisol and progesterone. All steroid concentrations were within the appropriate normal ranges. Of the mothers, 14.9% were depressed on all three scales. Significant correlations were seen between depression ratings and salivary progesterone and prolactin. In bottle-feeders, salivary progesterone was positively associated with depression, whereas in breast-feeders it was negatively associated. Plasma prolactin levels were inappropriately low in depressed breast-feeders. These data indicate that differing therapies may be appropriate for depression in breast- and bottle-feeders.

Adolescent↗
PubMed1989

The use of rating scales to identify post-natal depression.

One hundred and forty-seven mothers were screened for major depression at six to eight weeks post-partum. Using predetermined cut-off points, the Edinburgh Postnatal Depression Scale and the Beck scale were compared in their abilities to identify the 15% of subjects who had major depression according to DSM-III criteria. The sensitivity of Edinburgh scale was 95% and its specificity 93%. The performance of the Beck scale was markedly inferior, with a sensitivity of 68% and specificity of 88%.

Adult↗
PubMed1989

Suramin: an anticancer drug with a unique mechanism of action.

We administered suramin, an anti-parasitic drug and reverse transcriptase inhibitor, to 15 patients with metastatic cancer. This compound is known to inhibit the binding of growth factors (eg, epidermal growth factor [EGF], platelet-derived growth factor [PDGF], tumor growth factor-beta [TGF-beta]) to their receptors and thus antagonize the ability of these factors to stimulate growth of tumor cells in vitro. There were no complete responses (CRs), four partial responses (PRs) (two of ten adrenal cortex, one of four renal, one of one adult T-cell leukemia-lymphoma [HTLV-1]), and two minimal responses (MRs) (two of ten adrenal cortex). Toxicity included proteinuria (14 patients), reversible liver function test abnormalities (eight), vortex keratopathy (five), adrenal insufficiency (three), coagulopathy secondary to increased circulating levels of glycosaminoglycans (11), and one case of a reversible acute demyelinating polyneuropathy resembling the Guillain-Barrè syndrome. We conclude that suramin is an active agent in the treatment of metastatic cancer, and further work is necessary to define its scope.

Adenocarcinoma↗
PubMed1989

Characterization of the pseudocapsule of soft-tissue sarcomas. An experimental study in rats.

The effect of preoperative radiation therapy on the pseudocapsule of experimental rat soft-tissue sarcomas has not been histologically evaluated in a controlled study. The irradiated animal showed marked thickening of the capsular structure surrounding the sarcoma. Everywhere morphologically distinct from the tumor, there was no evidence of tumor invasion into or through this capsular structure. The membrane was consistently thicker and more hyalinized than in the control animals. The nonirradiated animals showed a minimal pseudocapsular structure with a characteristic tumor penetration. Irradiation produced distinct histologic changes in the pseudocapsule. Although assumed on the basis of clinical observations alone, irradiation-induced pseudocapsule has not previously been demonstrated in an experimental model of soft-tissue sarcoma.

Animals↗
PubMed1989

[Adult respiratory distress syndrome, a manifestation of severe pneumococcal infection].

A retrospective study analyzing the case notes of 49 hospitalized adults, either in intensive care (n = 26) or in thoracic medicine units (n = 23), for acute bacteriologically proven pneumococcal pneumonia based on samples obtained other than by sputum examination. The mortality was 54% in intensive care and 17% in the thoracic medicine unit. This significant difference may be explained in part by a respiratory distress syndrome in whom there were adequate criteria on admission for 7 patients in the intensive care group. Among these latter only one patient had had a splenectomy. The others did not have underlying disorders (three were chronic alcoholics); 7 patients were shocked on admission, four with a leukopenia less than 5,000/mm3 and six had a thrombocytopenia less than 100,000/mm3; finally 6 had a temperature of less than 38 degrees C. 7 patients died in less than four days (mean 2 days) in a clinical context of refractory hypoxemia. The significance of the respiratory distress syndrome is probably very different from the usual pneumonia; it seems rather to be an integration of the toxins induced by the pneumococcus. Its presentation can be particularly misleading as regards the diagnosis; the prescription of antibiotics once a diagnosis is obtained would seem insufficient by itself in this context to obtain a cure.

Adult↗