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Biomedical subjects

M McGregor

Publications and source records attributed to M McGregor.

At least 91 records · Page 5Linked to original sources
PubMed1984

Possible interactions of indomethacin and nitrates in angina pectoris.

Intravenous indomethacin has been reported to diminish coronary flow in patients with angina. There is also evidence that indomethacin attenuates or abolishes the coronary dilator and venodilator effects of nitroglycerin. In 11 patients with stable angina of effort, prior administration of 100 mg of indomethacin appeared to increase (0.10 greater than p greater than 0.05), rather than reduce, the work load achieved compared with placebo on a double-blind basis. The increase in work load when patients were given nitroglycerin was not significantly changed after they were given indomethacin. Therefore, this study does not support the suggestion either that prostaglandins play a significant role in coronary vasoregulation on effort or that prostacyclin is an important mediator of the therapeutic action of nitroglycerin. From a practical therapeutic viewpoint, there is apparently no danger of aggravating stable, exercise-induced angina or of abolishing the benefit normally expected from nitroglycerin when patients with angina are given indomethacin in doses comparable to those used in this study.

Aged↗
PubMed1984

Myocardial ischemia. Towards better use of the coronary care unit.

The coronary care unit is an expensive facility. Attempts to prove its value have not been successful, and the difficulty of doing so is considerable. In the absence of proof, it is nevertheless still necessary to establish a reasonable approach to the use of this facility. Such an approach and the evidence in its support are summarized. Pending the acquisition of more accurate predictors of risk, the following arbitrary guidelines are suggested. The coronary care unit is an appropriate environment for the management of dangerous arrhythmias and the major complications of infarction, for the management of resting angina until asymptomatic for 24 hours, and for the management of uncomplicated infarction in the absence of all predictors of risk for a period of 24 hours after the last episode of ischemic pain. Longer observation may be desirable for patients with certain predictors of short-term risk.

Angina Pectoris↗
PubMed1984

An evaluation of some of the methods currently available for the production of leucocyte-poor blood.

Four methods used for the production of leucocyte-poor blood were compared: liquid nitrogen recovery and washing, washing alone, the Imugard filter and the Leuko-Pak filter. Twenty units of blood were tested by each technique. Liquid nitrogen recovery and washing, and the Imugard filter removed over 95% of white cells, and 95% and 56% respectively of platelets. Washing alone was unreliable and removed on average 47% of white cells and 85% of platelets. The Leuko-Pak filter removed on average 42% of white cells and 79% of platelets.

Blood Transfusion↗
PubMed1984

A critical investigation of the Oxford tumour marker Ca1 in the histological diagnosis of breast cancer and pre-cancer.

Ca1 antibody reacted focally with all of the 20 cancers examined, but also with 12 out of 13 fibroadenomata and with each of 20 normal breasts. These observations indicate that there are severe limitations to the use of Ca1 antibody for defining benign versus malignant processes. Ca1 is most specific in terms of the cytoplasmic staining of tumours versus normal tissues. If a hierarchy of maximal staining is drawn up, cancers and fibroadenomata appear at the top, with normal tissue found in various types of breast in the middle, and non-neoplastic lesion such as epitheliosis, hyperplasia and apocrine change at the bottom of the hierarchy. There is a growing list of non-cancerous tissues which show reactivity to Ca1. In July 1983 this list numbered about 15. The designation 'Ca' is inappropriate.

Adolescent↗
PubMed1983

Validity of the hepatojugular reflux as a clinical test for congestive heart failure.

This study describes observations designed to test the validity of the hepatojugular reflux as an indicator of actual or incipient heart failure. The central venous pressure (CVP) could be predicted from the height of the jugular venous pulsations in 44 of 48 comparisons. In the remaining comparisons, discrepancies ranged from 5 to 7 mm Hg. In patients with normal resting cardiac function, abdominal compression did not cause an increase in CVP of greater than 2 mm Hg (2.7 mm H2O). In 16 of 19 patients with impaired function, CVP increased by greater than or equal to 3 mm Hg. The increase in CVP was estimated from neck veins to within 2 mm Hg in all but 3 instances. CVP stabilized by 10 seconds and did not change over the subsequent 60 seconds. Abdominal compression caused no consistent change in cardiac output. Changes in venous pressure could not be attributed to changes in esophageal pressure or to compression of the heart by elevation of the diaphragm. Observations were consistent with the hypothesis that an increase in right-sided cardiac filling pressures resulting from abdominal compression carried out as described here, reflects both the volume of blood in the abdominal veins and the ability of the ventricles to respond to increased venous return, and constitutes a useful clinical test for detecting congestive cardiac failure. An increase of 3 cm in the height of neck vein distention is a reasonable upper limit of normal.

Abdomen↗
PubMed1983

Pathogenesis of angina pectoris and role of nitrates in relief of myocardial ischemia.

The pathophysiologic mechanism of angina of effort has been understood for one and three-quarter centuries. However, the mechanisms underlying angina at rest are still largely unknown. Coronary spasm, whatever its mechanism, clearly causes Prinzmetal's variant angina. However, evidence that spasm is the cause of all angina at rest is wanting. Rather than spasm, it is suggested that most attacks may be the result of normal fluctuations in the tone of conductive coronary arteries in the presence of critical levels of organic obstruction. The nitrates both relieve coronary spasm and diminish normal coronary tone. They also affect the systemic circulation, so as to favorably influence the level of energy demand.

Angina Pectoris↗
PubMed1983

A prospective phase II clinical trial of continuous FUDR regional chemotherapy for colorectal metastases to the liver using a totally implantable drug infusion pump.

A prospective phase II evaluation of regional FUDR chemotherapy using a totally implantable drug infusion pump was conducted in 81 patients with colorectal metastases to the liver. The survival results were compared to a historical control group of 129 patients with isolated liver metastases. The two groups were comparable with respect to their dominant prognostic factors. The pump patients received their continuous chemotherapy on an outpatient basis and had an 88% response rate, as evidenced by a fall in their serum CEA levels by one-third or greater after two cycles of chemotherapy. By four criteria, the regional chemotherapy patients had an improved survival rate compared to the control series. First, the 1 year survival and median survival was better for the entire group of pump patients vs. controls (82% vs. 36%, 26 months vs. 8 months, p less than 0.0001). The survival for the regional chemotherapy patients was not influenced by the extent of tumor involvement, whether previous systemic 5-FU was given, or whether the patient had symptomatic disease. Second, the entire group of regional chemotherapy patients (including nonresponders) had a greater 1 year survival compared to the most favorable subgroup of control patients with the following characteristics: normal liver function tests, no symptoms, and only one lobe involved (82% vs. 66%, p = 0.009). Third, a subgroup of 49 pump patients, whose initial treatment for metastatic disease was regional chemotherapy (within 3 months of diagnosis) had a better 1 year survival than an exactly matched group of 49 control patients (67% vs. 30%, p = 0.000003). Fourth, the actuarial survival for all 81 pump patients was significantly better than predicted by a mathematical model constructed to predict the patient's clinical course based upon the seven dominant prognostic variables identified in a multifactorial analysis (82% survival at 1 year vs. 33% predicted survival). While liver metastases could be controlled in most patients, the major cause of death was tumor progression in extrahepatic sites, particularly lung metastases and abdominal carcinomatosis. Although it appears that regional chemotherapy with an implantable pump appears to prolong life by 12 to 18 months more than matched historical controls, these results must be confirmed by a randomized (phase III) prospective clinical trial.

Clinical Trials as Topic↗
PubMed1983

A study of the routine use of the Imugard IG500 Leukocyte Removal Filter illustrating a possible cause of transfusion reactions and a method of prevention.

The results of the use of the Imugard IG500 Leukocyte Removal Filter in the transfusion of 100 patients requiring leucocyte poor blood are presented. The patients were suffering from a variety of disorders. Many of them had previously received leucocyte poor blood prepared by other methods. Five patients developed non-haemolytic transfusion reactions. Subsequent investigations suggested that these were reactions to the plasma proteins present in the leucocyte poor blood prepared by filtration. A simple method of removal of these plasma proteins combined with filtration is described. The resultant product has been transfused, without incident, into the patients who previously reacted.

Anemia, Sideroblastic↗
PubMed1983

Post-surgical sacroiliac joint syndrome.

The sacroiliac joint can give rise to a syndrome of buttock and leg pain which is often difficult to differentiate from other causes of low--back pain. In some cases the syndrome may go unrecognized and may be a contributing factor in failed low-back surgery. The syndrome often occurs in the presence of lumbar spine disorders and may continue to cause pain after successful conservative or surgical treatment to the lumbar spine. The purpose of this paper is to review the anatomy, biomechanics, pathology, diagnosis and treatment of sacroiliac syndrome. Three case studies are presented to illustrate some of the main features of the syndrome, particularly in patients that have undergone previous spinal surgery.

Back Pain↗
PubMed1981

Hospital costs: can they be cut?

Major surgery is often proposed for "malignant hypertrophy of national health budgets." But before proceeding with such radical intervention, we need a better understanding of the "disease." Neither the United States nor Canada has a method to determine the right percentage of GNP to spend in the health area; no index of productivity or need is available. Yet an understanding of the mechanisms of growth of health budgets will permit our using strategies to reduce the rate of health spending.

Attitude to Health↗