Biomedical subjects

B McAdam

Publications and source records attributed to B McAdam.

6 recordsLinked to original sources

PubMed1999

Effects of specific inhibition of cyclooxygenase-2 on sodium balance, hemodynamics, and vasoactive eicosanoids.

Conventional nonsteroidal anti-inflammatory drugs inhibit both cyclooxygenase (Cox) isoforms (Cox-1 and Cox-2) and may be associated with nephrotoxicity. The present study was undertaken to assess the renal effects of the specific Cox-2 inhibitor, MK-966. Healthy older adults (n = 36) were admitted to a clinical research unit, placed on a fixed sodium intake, and randomized under double-blind conditions to receive the specific Cox-2 inhibitor, MK-966 (50 mg every day), a nonspecific Cox-1/Cox-2 inhibitor, indomethacin (50 mg t.i.d.), or placebo for 2 weeks. All treatments were well tolerated. Both active regimens were associated with a transient but significant decline in urinary sodium excretion during the first 72 h of treatment. Blood pressure and body weight did not change significantly in any group. The glomerular filtration rate (GFR) was decreased by indomethacin but was not changed significantly by MK-966 treatment. Thromboxane biosynthesis by platelets was inhibited by indomethacin only. The urinary excretion of the prostacyclin metabolite 2,3-dinor-6-keto prostaglandin F1alpha was decreased by both MK-966 and indomethacin and was unchanged by placebo. Cox-2 may play a role in the systemic biosynthesis of prostacyclin in healthy humans. Selective inhibition of Cox-2 by MK-966 caused a clinically insignificant and transient retention of sodium, but no depression of GFR. Inhibition of both Cox isoforms by indomethacin caused transient sodium retention and a decline in GFR. Our data suggest that acute sodium retention by nonsteroidal anti-inflammatory drugs in healthy elderly subjects is mediated by the inhibition of Cox-2, whereas depression of GFR is due to inhibition of Cox-1.

6-Ketoprostaglandin F1 alpha↗

PubMed1996

Health care focus documentation--more efficient charting.

A revised nursing documentation system is now user-friendly, multi-disciplinary and computer adaptable. Sixteen health care focus topics replaced nursing diagnoses and served as a common thread to coordinate documentation of patient care.

Efficiency, Organizational↗

PubMed1996

Transdermal modification of platelet function: an aspirin patch system results in marked suppression of platelet cyclooxygenase.

Aspirin inhibits platelet cyclooxygenase and prevents thromboxane A2 (TXA2) production. Although it is an effective antithrombotic, even at a low doses aspirin may induce gastrointestinal toxicity. We examined the feasibility of delivering aspirin transdermally using two patch systems, one without (type A) and one with (type B) the permeation enhancer limonene. Daily application of two type A patches that had a total surface area of 100 cm2 and contained 84 mg/patch resulted in 85% +/- 6% reduction in serum TXB2 in six male subjects by day 14. Suppression of serum TXB2 was less marked in females (32% +/- 16%). Analysis of the residual drug in the patch showed that each patch delivered 18 +/- 3 mg on day 1 and 17 +/- 4 mg on day 14, with no difference between males and females. Daily application of a single patch B that had a surface area of 50 cm2 and contained 120 mg aspirin resulted in 60% +/- 11% suppression of serum TXB2 by day 14 in nine male subjects and 84% +/- 9% suppression by day 21. Analysis of the applied patches showed that patch B delivered 33 +/- 3 mg of aspirin daily. Plasma aspirin and salicylate were determined by gas chromatography, mass spectrometry. No aspirin was detected, whereas plasma salicylate was 157 +/- 38 ng/ml and 133 +/- 20 ng/ml by day 14 with patch A and patch B, respectively. Analysis of aspirin applied by patch to the skin in three subjects showed marked hydrolysis to the inactive product, salicylic acid. Aspirin can be delivered transdermally by patch in a dose that suppresses platelet cyclooxygenase. The delivery rate is low reflecting hydrolysis of the drug in the skin. Delivery is improved by the permeation enhancer limonene. This novel route of delivery may be applicable to other antithrombotics and may limit the risk of gastrointestinal toxicity.

Administration, Cutaneous↗

PubMed1993

Percutaneous endoscopic gastrostomy--results of an Irish single unit series.

The technique of percutaneous endoscopic gastrostomy (PEG) was first described in 1980, as an alternative to traditional surgical methods. The main indication for PEG is the need for longterm nutritional support. It is reported to have many advantages over surgical gastrostomy, being safer and cheaper. We reviewed our experience with the first 44 patients referred to our unit for PEG. The most common indications for referral were stroke, head injury and post brain surgery. There was a success rate of 97.6% and a complication rate of 13.8%. One patient (2.3%) suffered major complications as a result of early tube displacement. There were no procedure related deaths in our series and no deaths as a result of an underlying disease process within 30 days, reflecting appropriate patient selection. All patients benefited nutritionally from PEG placement. Two patients recovered sufficiently to no longer require a gastrostomy and the tube was easily removed in both cases.

Brain Neoplasms↗

PubMed1993

Lactate dehydrogenase levels during MACOP-B chemotherapy for non-Hodgkin's lymphoma.

Lactate dehydrogenase (LD) levels rose consistently during MACOP-B chemotherapy for intermediate and high-grade non-Hodgkin's lymphoma (NHL). Levels peaked at week nine and fell to normal within six weeks of completion of therapy. Isoenzyme patterns, studied prospectively in seven patients, showed a parallel rise in LD1 and LD2 suggesting a source other than tumour tissue for the rise in total LD. In the absence of evidence of myocardial or renal damage, haematopoietic tissue was the most likely source. With no evidence of haemolysis, normal serum levels of vitamin B12 and folate and normal red cell folate, dyserythropoiesis was considered to be the underlying mechanism. A rising mean corpuscular volume further reinforced this suggestion. Intensive use of methotrexate along with co-trimoxazole as prophylaxis against pneumoycystis carinii is considered the most likely cause of marrow dysfunction. Failure to recognise that rising LD levels during such therapy is treatment-related, rather than of tumour origin, may lead to inappropriate change or abandonment of therapy.

Adult↗

PubMedDate not supplied

Lateral and anterior reciprocal electrocardiographic changes: relationship to ST segment elevation and underlying coronary artery disease in inferior myocardial infarction.

The electrocardiogram in patients with acute inferior myocardial infarction frequently displays ST depression in non-infarct leads. The significance of this finding is uncertain. The relationship between ST depression, ST elevation and arteriographic severity of coronary artery disease was explored. 22 patients with acute inferior myocardial infarction, receiving thrombolysis and undergoing acute (within seven hours of the onset of chest pain) coronary angiography were studied prospectively. The electrocardiographic ST segment elevation in the inferior leads and ST segment depression in the lateral and in the anterior precordial leads were measured. In each group of leads, the maximum value of ST deviation in any lead as well as the sum of the values for ST deviation in the individual leads was determined. Gensini scores of total coronary artery disease and component scores for the major coronary arteries were determined from the coronary arteriogram. There was a strong correlation of maximum inferior ST elevation with both maximum lateral ST depression (r = 0.96, p < 0.001) and with maximum anterior precordial ST depression (r = 0.78, p < 0.001). The corresponding correlations for sum of ST deviations were r = 0.91, p < 0.001 and r = 0.79, p < 0.001 respectively. There was no relationship between Gensini scores of coronary artery disease and measures of electrocardiographic ST segment depression or elevation. Electrocardiographic ST depression in non-infarct leads in patients with inferior myocardial infarction, does not provide information regarding the degree of coronary artery disease. The ST depression in both lateral and anterior precordial leads correlates with and is a reflection of inferior ST elevation.

Adult↗