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Biomedical subjects

D MacLeod

Publications and source records attributed to D MacLeod.

16 recordsLinked to original sources
PubMed1994

Acute and long-term outcome of directional coronary atherectomy for stable and unstable angina.

The clinical efficacy and safety of directional coronary atherectomy for the treatment of stable and unstable angina were assessed in 82 patients with stable and 68 patients with unstable angina. Therefore, clinical and angiographic follow-up was obtained in a prospectively collected consecutive series of 150 atherectomy procedures. Restenosis was assessed clinically and by quantitative angiography. The overall clinical success rate of atherectomy for patients with unstable and stable angina was 88% and 91%, respectively. No significant differences were found for in-hospital event rates between the unstable and stable angina groups: death (1.5% vs 0%), myocardial infarction (10% vs 6%), and emergency bypass operation (3% vs 2%). These clinical events were related to the occurrence of abrupt occlusions (8.8% in patients with stable and 6.1% in those with unstable angina; p = NS). Clinical follow-up was achieved in 100% of the patients with stable and unstable angina at a mean interval of 923 and 903 days, respectively. Two-year survival rates were 96% and 97% in the populations with unstable and stable angina, respectively. There were no significant differences with respect to bypass surgery and angioplasty, but event-free survival at 2 years was significantly lower in the unstable (54%) than the stable (69%) angina group. Quantitative coronary angiography did not detect any difference in luminal renarrowing during the 6-month angiographic follow-up period. Although directional coronary atherectomy can be performed effectively in patients with unstable and stable angina, the long-term clinical outcome was less favorable in the unstable angina group.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1993

Within-breath measurement of respiratory impedance.

The measurement of the complex respiratory impedance at a high temporal resolution is described. The measurement of impedance is correlated with the breathing cycle using electrical transthoracic impedance. This allows the determination of the complex impedance at any fixed point in the respiratory cycle, which results in lower variability in the measured data when compared to the original device. The respiratory impedance in normal subjects fluctuates during the breathing cycle and has two maxima during a single breath, which occur at peak inspiratory and expiratory flow. In addition, the measurement of impedance at a high temporal resolution enables the observation of novel features in the impedance which appear to be associated with certain respiratory disorders.

Adult↗
PubMed1992

Nicorandil and cardiovascular performance in patients with coronary artery disease.

To establish the cardiovascular profile of nicorandil in patients with coronary artery disease, we recently conducted three studies at our institution. In two groups of patients undergoing cardiac catheterization, the effects of 20 mg nicorandil sublingually (s.l.) on, first, left ventricular hemodynamics (n = 10) and, second, coronary vasodilatation (n = 11) were investigated. In the first group, despite a significant decrease of 12% in left ventricular systolic pressure, heart rate did not increase significantly after nicorandil. Both left ventricular end-diastolic pressure (-43%) and the time constant of early isovolumic relaxation (-11%) decreased, whereas peak Vce and Vmax increased (+19%) (all significantly). In the second group, as mean aortic pressure decreased (-13%, p < 0.05), coronary sinus blood flow did not change significantly, and calculated coronary vascular resistance tended to decrease (-10%). Myocardial oxygen consumption decreased significantly by 14%. Quantitative coronary angiography confirmed a significant increase in the mean diameter of nonstenotic coronary artery segments (+ 14%, n = 43) and, importantly, in mean obstruction diameter of stenotic segments (+ 14%, n = 7) after s.l. nicorandil. In a third continuing study, the effects of intracoronary (i.c.) nicorandil (6 micrograms/kg) and isosorbide dinitrate (2 mg) on the epicardial coronary arteries were investigated in 10 patients undergoing coronary angioplasty. In nonstenotic coronary artery segments, mean coronary diameter increased significantly after either nicorandil (+ 12%) or isosorbide dinitrate (+ 17%). In stenotic segments, however, where the increase in obstruction diameter (+ 20%) after i.c. nicorandil was significant, the 8% increase of isosorbide dinitrate was not.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Sublingual↗
PubMed1990

A nuclear protein that binds preferentially to methylated DNA in vitro may play a role in the inaccessibility of methylated CpGs in mammalian nuclei.

The effects of DNA methylation on gene expression and chromatin structure suggest the existence of a mechanism in the nucleus capable of distinguishing methylated and non-methylated sequences. We report the finding of a nuclear protein in several vertebrate tissues and cell lines that binds preferentially to methylated DNA in vitro. Its lack of sequence-specific requirements makes it potentially capable of binding to any methylated sequence in mammalian nuclei. An in vivo counterpart of these results is that methylated CpGs are inaccessible to nucleases within nuclei. In contrast, non-methylated CpG sites, located mainly at CpG islands, and restriction sites not containing this dinucleotide, are relatively accessible. The possibility that DNA methylation acts through binding to specific proteins that could alter chromatin structure is discussed.

Animals↗
PubMed1987

Ventricular septal defect after myocardial infarction: assessment by cross sectional echocardiography with pulsed wave Doppler scanning.

Eight patients who developed a ventricular septal defect after myocardial infarction were assessed by cross sectional echocardiography and pulsed wave Doppler scanning. Cross sectional echocardiography visualised the defect in four patients and gave an accurate assessment of global and regional left ventricular function in all eight. In all patients pulsed wave Doppler scanning detected turbulent flow at the apex of the right ventricle or adjacent to a wall motion abnormality affecting the interventricular septum. Pulsed wave Doppler detected coexisting mitral regurgitation in one patient and tricuspid regurgitation in another two. In all patients a left to right shunt was confirmed by oximetry and the location of the defect was identified by angiography or at operation or necropsy. Cross sectional echocardiography in combination with pulsed wave Doppler scanning is useful in the rapid bedside evaluation of patients with ventricular septal defect after myocardial infarction.

Aged↗
PubMed1986

Felodipine as a replacement for minoxidil in the treatment of severe hypertension.

The new calcium antagonist felodipine has been compared with minoxidil in the management of severe hypertension in a group of 17 men. Satisfactory control of blood pressure was achieved in all patients with a combination of beta blocker, loop diuretic and minoxidil after inadequate control on a standard regimen of beta blocker, thiazide and vasodilator. The optimal dose of felodipine was titrated after a placebo phase. In a double blind crossover trial blood pressure on felodipine (150/88 +/- 19/8 mmHg, SD) was the same as on minoxidil (148/87 +/- 23/11 mmHg, NS) and the postural difference was similar (NS) on both drug regimens. Body weight was lower on the felodipine regimen (P less than 0.01), as was supine heart rate (P less than 0.05). There was a small rise in plasma liver enzymes on felodipine therapy (P less than 0.01). Felodipine was well tolerated and may be useful in the management of severe hypertension.

Aged↗
PubMed1985

Felodipine can replace minoxidil in the treatment of refractory hypertension.

In a group of 15 men with severe hypertension in a double-blind crossover trial, the new calcium antagonist felodipine has been shown to lower blood pressure as effectively as minoxidil when used in combination with a beta-blocker and a loop diuretic. Felodipine was well tolerated and may have a role in the management of severe hypertension.

Aged↗
PubMed1975

Exogenous fungal endophthalmitis caused by Paecilomyces.

A 17-year-old white boy developed a fulminating corneal infection and endophthalmitis in his left eye after trauma. He was treated with antibiotics and corticosteroids for one week prior to diagnosis. A saprophytic fungus, Paecilomyces viridis, was cultured from corneal scrapings and was demonstrated in the vitreous cavity by histopathologic examination.

Adolescent↗
PubMedDate not supplied

A clinico-pathological study of 79 bronchoscopies in HIV-positive patients.

We investigated lung pathology in 61 HIV-positive patients who underwent 79 bronchoscopies. There were 27 cases of pneumocystis carinii pneumonia (PCP), 22 cases of pyogenic pulmonary infection and six cases of mycobacterial infection. Eleven cases of non-specific interstitial pneumonitis were found and 10 intravenous drug abusers had birefringent pulmonary talc granulomata in biopsy specimens. Women and intravenous drug abusers had higher rates of pyogenic pulmonary infection than men and other risk groups respectively. When compared with a previous survey from the same hospital using the same methodology the present study showed a change in the risk groups with 50% more intravenous drug abusers, 42% more haemophiliacs and 45% fewer patients with sexually transmitted infection. However, apparent changes in the spectrum of diseases encountered were not significant.

Adolescent↗