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Biomedical subjects

M Savage

Publications and source records attributed to M Savage.

At least 19 recordsLinked to original sources
PubMed1992

Preparation and opioid activity of analogues of the analgesic dipeptide 2,6-dimethyl-L-tyrosyl-N-(3-phenylpropyl)-D-alaninamide.

A number of analogues of the recently disclosed analgesic dipeptide 2,6-dimethyl-L-tyrosyl-D-alanine-phenylpropylamide (SC-39566, 2) were prepared. These analogues contained oxymethylene, aminomethylene, ketomethylene, bismethylene, and trans double bond (including vinyl fluoride) isosteric replacements for the amide bond between the D-alanine and phenylpropylamine units in 2. These compounds were tested in opioid binding assays and in the mouse writhing assay for analgesic activity. Though not as potent as 2, the oxymethylene, and trans double bond isosteres showed analgesic activity. The aminomethylene analogues also showed binding activity in subnanomolar concentrations at the mu receptor. The amide bond between 2,6-dimethyl-L-tyrosine and D-alanine units seems to be critical for opioid activity.

Analgesics, Opioid↗
PubMed1992

Nocardia infection in AIDS: a clinical and microbiological challenge.

A case of Nocardia asteroides pneumonia was diagnosed after death in a patient with AIDS. Six sputum cultures and one bronchoalveolar lavage fluid contained no pathogens, and no growth was obtained from one pleural fluid aspirate. None of these specimens was incubated for more than two days. Extended incubation for mycobacteria also failed to help in the diagnosis. N asteroides was isolated from pus taken from the lung cavity during the post mortem examination. It is suggested that if nocardiosis enters the differential diagnosis all specimens should be cultured for at least two weeks and the use of selective media be considered. This case highlights the need for clinicians to maintain a high index of suspicion for this pathogen.

Acquired Immunodeficiency Syndrome↗
PubMed1992

Restenosis after placement of Palmaz-Schatz stents in native coronary arteries. Initial results of a multicenter experience.

BACKGROUND: Several metallic intracoronary stents are currently undergoing preliminary evaluation to ascertain potential benefit as means to reduce the 30-40% incidence of restenosis after balloon angioplasty. METHODS AND RESULTS: To determine the incidence and correlates of restenosis after placement of Palmaz-Schatz stents in native coronary arteries in the first group of patients selected for this procedure, clinical and quantitative angiographic data from 206 consecutive patients (221 stenoses) with successful stent placement (diameter stenosis < 50%) were analyzed. Six patients (2.9%) had thrombosis-mediated stent closure within 1 month after stent placement and were excluded from long-term angiographic follow-up. One hundred eighty-one (91%) of the remaining 200 patients had angiography at 5.8 +/- 2.1 months. Patients with and without follow-up did not differ in any baseline characteristic; in particular, history of restenosis at the site stented (73% versus 65%), placement of multiple overlapping stents (17% versus 20%), and mean poststent diameter stenosis (16 +/- 12% versus 14 +/- 12%). The overall incidence of restenosis (diameter stenosis > or = 50% at follow-up) in this group at high risk for restenosis was 36% (95% confidence interval, 29-43%) on a per-stenosis basis. The incidence of restenosis when a single stent was placed was 30% (95% confidence interval, 23-37%). Risk was dependent upon a history of restenosis (present versus absent 36% versus 16%, p = 0.02) and upon whether or not a poststent stenosis < or = 0% was achieved (6% versus 33%, p = 0.02). When multiple overlapping stents were placed, restenosis occurred at 64% of sites, and placement of multiple stents was discouraged during the later phases of this study as these results became apparent. CONCLUSIONS: Although multiple stents appear to yield a poor long-term result, placement of single stents may offer a benefit compared with standard coronary angioplasty, particularly if an excellent angiographic result can be obtained in patients without prior restenosis. Further randomized trials in such patients are needed.

Coronary Angiography↗
PubMed1991

Medical audit--why children attend out-patient clinics.

Ten thousand new out-patient referrals are made each year to the out-patient department of the Royal Belfast Hospital for Sick Children. A prospective study of a random sample of 295 (4%) of these children was undertaken to determine their reason for referral and the outcome of their attendance. The stated reason for referral was for investigation/diagnosis (45%), therapeutic advice (47%) or parental reassurance (6%). Non-attenders (10%) could not be predicted from the referral letter. Twenty-four per cent were found to have no abnormality. Significantly more children referred for parental reassurance and infants were included in this category. Less than half (45%) had investigations performed. These were mainly non-invasive with plain x-rays and urinalysis accounting for 44%. Consultant medical staff saw 53% of new referrals and requested more investigations but were less likely to review patients. The information obtained is used to suggest ways in which more rational use of hospital resources might be achieved without decreasing the standard of care to these children.

Ambulatory Care Facilities↗
PubMed1989

Surface electrocardiogram in the detection of transmural myocardial ischemia during coronary artery occlusion.

To examine whether coronary occlusion causing transmural ischemia was accurately reflected by ST-segment elevation on routine electrocardiograms, intracoronary and surface electrocardiograms were simultaneously recorded during percutaneous transluminal coronary angioplasty (PTCA). The study group consisted of 54 patients who had intracoronary ST-segment elevation during transient coronary occlusion (left anterior descending [LAD]: 25 patients, left circumflex [LC]: 19 patients, right coronary artery: 12 patients). Elevation of the ST segment on the surface electrocardiogram (greater than or equal to 0.1 mV) was recorded in 84% of patients during LAD dilatation, in 32% of patients during LC dilatation (p less than 0.01 vs LAD and right), and in 92% of patients during right coronary dilatation (not significant vs LAD). The magnitude of intracoronary ST elevation was 1.10 +/- 0.8, 1.68 +/- 1.2 and 0.8 +/- 0.6 mV for the LAD, LC and right occlusions, respectively (not significant). Thus, despite the comparable magnitude of intracoronary ST elevation, LC occlusion resulted in ST-segment elevation on the surface electrocardiogram in significantly fewer patients than did LAD or right occlusion. During LC occlusion, 9 patients had no electrocardiographic changes and 4 had only precordial ST depression. Thus, in patients with transmural ischemia during right or LAD occlusions, concordant ST elevation on the surface electrocardiogram is common. In contrast, ST-segment elevation is an insensitive marker of LC occlusion. In patients with ongoing ischemic symptoms and isolated precordial ST depression or no repolarization abnormalities, LC occlusion should be considered in the differential diagnosis.

Adult↗
PubMed1989

Myocardial salvage after regional beta-adrenergic blockade.

UNLABELLED: The aim of the study was to determine whether regional beta-adrenergic blockade via the coronary sinus limited myocardial damage after coronary artery occlusion in the canine model. Accordingly, open-chest anesthetized dogs were randomly allocated to one of three groups: a control group and groups treated with propranolol (in doses of 0.02, 0.2, and 2.0 mg/kg) given either intravenously or via the coronary sinus. The hypoperfused zone (i.e., risk area) and the extent of myocardial damage were assessed by autoradiography and triphenyltetrazolium chloride staining, respectively. Myocardial damage expressed as a percent of the hypoperfused zone was 84 +/- 5% in the control group (n = 9) and 78 +/- 7% (0.02 mg/kg, n = 7, NS), 63 +/- 6% (0.2 mg/kg, n = 7, p less than 0.05), and 62 +/- 7% (2.0 mg/kg, n = 9, p less than 0.02) in the groups receiving intravenous propranolol and 73 +/- 6% (0.02 mg/kg, n = 7, NS), 58 +/- 7% (0.2 mg/kg, n = 7, p less than 0.01), and 44 +/- 9% (2.0 mg/kg, n = 9, p less than 0.001) in groups receiving propranolol via the cardiac veins. There was a significant enhancement of myocardial salvage with increasing doses of propranolol delivered via the cardiac veins (linear regression trend, p less than 0.05). In contrast, myocardial damage expressed as a percent of the hypoperfused zone remained comparable with propranolol doses of 0.2 and 2.0 mg/kg administered intravenously (linear regression trend, NS). IN CONCLUSION: (1) regional beta-adrenergic blockade via the cardiac veins afforded significant myocardial salvage and (2) the regional administration of propranolol resulted in significant reduction of myocardial damage in a dose-dependent fashion.

Administration, Topical↗
PubMed1989

High-pressure portable pneumatic drive unit.

The left ventricular assist device (LVAD) of the Cleveland Clinic Foundation (CCF) is a single-chamber assist pump, driven by a high-pressure pneumatic cylinder. A low-cost, portable driver that will allow cardiac care patients, with a high-pressure pneumatic ventricle assist, more freedom of movement has been developed. The compact and light-weight configuration can provide periods of 2 h of freedom from a fixed position driver and does not use exotic technology.

Costs and Cost Analysis↗
PubMed1988

Protection of the ischemic myocardium during percutaneous transluminal coronary angioplasty.

Therapeutic balloon coronary angioplasty provides a useful model for studying the effects of epicardial coronary artery occlusion in conscious humans. In addition, it is a potent model in which the effectiveness of interventions designed to ameliorate ischemia can be evaluated. Whereas intravenous beta-adrenergic blocking drugs and nitrates appear to have a limited protective effect, the regional (i.e., intracoronary) use of beta-adrenergic blocking drugs and calcium antagonists seem more potent. Currently, coronary venous retroperfusion with arterial blood does not appear practical, and the intraaortic balloon is a useful adjunctive measure in relatively few patients undergoing percutaneous transluminal coronary angioplasty. In contrast, the direct anterograde delivery of oxygen-rich blood or fluorocarbons holds promise as a reliable means of providing local myocardial protection. If ischemia could be markedly reduced, percutaneous transluminal coronary angioplasty might be applied safely in more high-risk clinical settings. In addition, if prolonged balloon inflation could be performed, there might be an increase in primary success rate and possibly a reduction in restenosis rate.

Adrenergic beta-Antagonists↗
PubMed1988

Recurrent ischemia in the zone of prior myocardial infarction: results of coronary angioplasty of the infarct-related artery.

We studied the efficacy of coronary angioplasty (PTCA) of the infarct-related artery in 54 patients with recurrent myocardial ischemia in the zone of prior infarction. Our patients had recurrent ischemia 10 +/- 7 days after infarction, with 75% experiencing rest angina and 15% having evidence of reinfarction. Angiography of the infarct-related artery demonstrated a critical stenosis in 35 of 54, a subtotal occlusion in 5 of 54, and a total occlusion in 14 of 54. PTCA was successful in 94% of critical stenoses, 80% of subtotal occlusions, but in only 50% of total occlusions. Complications related to PTCA included a 3.7% rate of emergency surgery, but no deaths or infarctions. During the clinical follow-up period of 11 +/- 7 months, there was one reinfarction and no deaths. Although 27% of our 44 patients with a successful initial PTCA required a second revascularization procedure for recurrent angina, 40 patients (91%) remained symptomatically improved with angioplasty alone (including successful repeat PTCA in eight patients). We conclude that PTCA of the infarct-related artery is beneficial for selected patients with recurrent ischemia in the zone of prior infarction.

Adult↗
PubMed1988

Effect of hypertension and physical training on the morphology of the kidney with special reference to the juxtaglomerular cells.

Changes in blood pressure levels, renal structure and degree of granulation of the juxtaglomerular cells in Dahl S rats fed a normal or high salt diet are reported. The effect of physical training on the hypertensive state of these animals has also been described. Animals fed a high salt diet demonstrated increased blood pressure levels and decreased juxtaglomerular indices when compared with rats fed a normal diet. The extent of renal damage in these animals was observed to be proportional to the amount of sodium in the diet. Physical training, however, brought about a 15-25% reduction in blood pressure levels and decreased renal damage in Dahl S rats fed a normal or high salt diet. The mean juxtaglomerular index was observed to be 30% higher in trained animals fed a normal diet compared with non-trained controls. It is concluded that physical training helps minimize pathological changes in the kidney and effects a reduction in blood pressure levels in hypertensive Dahl S rats.

Animals↗
PubMed1986

Influence of tissue compressibility on calibration for strain-gauge plethysmography.

Strain gauges employed in plethysmography for determination of limb blood flow tend to counter the expansion of the limb during venous occlusion. Traditionally a mechanical calibration is performed in situ to compensate for tissue compressibility. Greenfield, Whitney, and Mowbray stated that, otherwise, large errors would result (Br. Med. Bull. 19: 101-109, 1963). Nonetheless, not all of the recent reports on skin blood flow in humans have been based on a calibration procedure that corrects for tissue compressibility. To evaluate the significance of this problem, we developed a new strain-gauge holder that made possible frequent, reproducible, stretching of a single-strand Whitney gauge in situ. We compared the apparent sensitivity thus obtained to electrical or bench mechanical determinations. We independently determined tissue compressibility by recording limb circumference as tension in a circumferential tube was varied. Both techniques showed that tissue compressibility is a small source of error (5%) and that compressibility decreases during occlusion. Therefore the cumbersome holder and potential artifacts associated with the traditional technique need not be tolerated. We also investigated the consequences of nonuniform tension distribution and temperature changes; practical considerations for dealing with these are discussed.

Adult↗
PubMed1985

The use of scintigraphic studies in mid-ventricular obstructive cardiomyopathy to rule out pseudoaneurysm.

A "pseudo-pseudo" aneurysm of the left ventricle due to mid-ventricular obstruction from asymmetric septal hypertrophy is presented. A case of mid-ventricular hypertrophic obstructive cardiomyopathy (MVHOCM) was evaluated by means of echocardiography, angiocardiography, gated cardiac blood pool scanning, and a TI-201 myocardial scan. The gated cardiac blood pool scan appearance of MVHOCM is similar to pseudoaneurysm of the left ventricle. TI-201 myocardial imaging, however, was able to distinguish between MVHOCM and pseudoaneurysm of the left ventricle.

Aged↗