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Biomedical subjects

M McDermott

Publications and source records attributed to M McDermott.

At least 91 records · Page 5Linked to original sources
PubMed1994

Cigarette smoking and the age at onset of a first non-fatal myocardial infarction.

BACKGROUND: Smoking is a major risk factor for coronary heart disease. Discontinuance of smoking is associated with a reduction in the risk of coronary disease; this risk approaches the level among non-smokers after stopping smoking for periods ranging from 6 months to several years. We analyzed pertinent prospectively accumulated data from our multicenter postinfarction studies to gain further insight into the complex relationship between cigarette smoking and the premature occurrence of a first myocardial infarction. METHODS: Retrospective analysis of the relationship between the number of cigarettes smoked and the age at onset of patients experiencing their first non-fatal myocardial infarction was investigated in 2445 patients. The intensity of smoking was quantitated in terms of the average number of packs per day smoked during adult years, subcategorized in increments of a half-pack per day up to more than two packs per day. Ex-smokers were identified if they had stopped smoking 1 month before their index infarction. Analysis of variance was used to adjust for the effects of relevant confounding risk factors. RESULTS: The adjusted age for first non-fatal infarction progressively declined with increasing smoking exposure, with an average age reduction of 8.7 years (95% confidence interval; 7.2, 10.2) in those smoking more than two packs per day compared with non-smokers. The graded effect was somewhat more marked in women than in men. The number of cigarettes smoked before infarction had no effect on the severity of the acute infarction or on mortality from cardiac causes during more than 2-year post-hospital follow-up. Those who stopped smoking 1 month or longer before the infarction were significantly older at the time of first infarction than active smokers in all smoking categories. CONCLUSION: This study provides strong evidence that active smoking is associated with an earlier age at onset of first infarctions, with a striking inverse dose-response effect. Stopping smoking appears to reduce the premature occurrence of coronary events.

Age of Onset↗
PubMed1994

Chronic Brucella infection of the supra-patellar bursa with sinus formation.

A case of supra-patellar bursitis with the formation of discharging sinus is described. B abortus was isolated from resected bursal tissue. While osteoarticular complications of brucellosis are common and a number of different clinical syndromes are now recognised, disease of the bursae is rare and as far as is known sinus formation has not been described before in this setting.

Adult↗
PubMed1994

The effect of deprenyl and tocopherol on cognitive performance in early untreated Parkinson's disease. Parkinson Study Group.

We conducted prospective cognitive assessments over 14 +/- 6 (mean +/- SD) months of observation as part of the multicenter trial Deprenyl and Tocopherol Antioxidative Therapy of Parkinsonism (DATATOP), which involved 800 patients with early untreated Parkinson's disease. We administered tests that measured memory, visuospatial, and frontal lobe functions. Subjects were randomly assigned to receive placebo, deprenyl (10 mg/d), tocopherol (2,000 IU/d), or both deprenyl and tocopherol. We analyzed treatment effects using annualized rates of cognitive change. We performed exploratory analyses to identify potential clinical and demographic correlates of cognitive performance. There was no significant effect of either deprenyl or tocopherol on cognitive test performance. In early untreated Parkinson's disease, cognitive performance appears to be stable and unrelated to either motor deterioration or treatment with deprenyl or tocopherol.

Aged↗
PubMed1993

Developing a stable bilateral model of parkinsonism in rhesus monkeys.

The non-human primate models of Parkinson's disease which have been developed using the neurotoxin MPTP (1-methyl-4-phenyl-1,2,3,6 tetrahydropyridine) have proven to be either unstable or variable, or to display only a limited subset of parkinsonian features. The present study examined a new two-stage lesion approach in which MPTP was administered via the carotid arteries. The first infusion through one artery produced a hemiparkinsonian state and was followed several months later by a second MPTP infusion into the contralateral carotid artery to induce bilateral parkinsonism. Animals receiving lesions were evaluated using a battery of tests which included a monkey parkinsonism rating scale, a movement time-task and continuous monitoring of home cage activity. All animals monitored showed significant decreases in activity levels of up to 95% following the second lesion. These decreased activity levels remained stable throughout the observation period of up to 12 months postlesion. In addition to the decreased home cage activity, bilaterally lesioned animals displayed bilateral parkinsonian features including akinesia, bradykinesia, rigidity, tremor and balance and gait disturbances which were stable, following an acute period of up to 45 days, for the remainder of the study. Administration of levodopa increased activity levels and reduced motor dysfunctions. Thus, a two-stage bilateral lesion approach, utilizing the neurotoxin MPTP, appears to provide a less variable and relatively stable model of bilateral Parkinson's disease in nonhuman primates. Treated animals display the cardinal features of parkinsonism and respond appropriately to the standard antiparkinsonian drug, levodopa.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1993

A pilot controlled study of fluoxetine for obsessive-compulsive symptoms in children with Tourette's syndrome.

We carried out a double-blind, randomized, parallel-groups clinical trial of fluoxetine (20-40 mg/day) and placebo in 11 children with Tourette's syndrome (TS) and associated obsessive-compulsive symptoms (OCS). The treatment period lasted 4 months. No significant differences between treatment groups were observed for measures of OCS. Fluoxetine therapy, however, was associated with a trend toward some improvement in tic severity, attentional abilities, and social functioning. Given these observations and the limitations of this pilot study, which include selection biases, small sample size, and significant placebo effects, the efficacy of fluoxetine in children with TS deserves further larger-scale investigation.

Adolescent↗
PubMed1993

Molecular changes during the photooxidation of alpha-crystallin in the presence of uroporphyrin.

Singlet oxygen reacts preferentially with three amino acids in proteins, His, Trp and Met. In order to study the specific molecular events that result from such oxidations, calf alpha-crystallin was photooxidized in the presence of uroporphyrin and the reactions were investigated by high performance liquid chromatography peptide mapping using a photodiode array detector followed by fast atom bombardment mass spectrometry (FAB-MS). From these studies, the following conclusions can be inferred: (1) Upon photooxidation residue Met-68 of the B chain is oxidized to Met sulfoxide, whereas residue Trp-60 remains intact. (2) Two of the 16 His residues in alpha-crystallin are photooxidized with an apparent pKa of ca 7.0 (3) FAB-MS analysis suggests that residue Lys-166 close to the C-terminal end of the A chain forms a cross-link with the His-7 residue close to the N-terminal end of the A chain. This may be either an inter- or intramolecular cross-link.

Amino Acid Sequence↗
PubMed1993

Fatal non-malignant ulceration in the gastric tube after oesophagectomy.

The clinical, histological, and necropsy findings of three cases of fatal, nonmalignant ulceration in the gastric tube after oesophageal resection for oesophageal malignancy are presented. The deaths occurred three, 30, and 42 months, respectively, after initial surgery. Two of the patients had received chemoradiotherapy, one at initial presentation, and one for a recurrence 18 months after surgery. In two patients death was due to an aspiration pneumonia, consequent on the development of a gastrobronchial fistula. The third patient died after a massive haematemesis. In none of the cases was there any evidence of residual or recurrent malignancy at necropsy, although in the two cases where radiological and endoscopic assessment was performed before death, recurrent tumour had been clinically diagnosed. As improved surgical techniques reduce the incidence of death due to anastomotic leakage and combined modality treatment regimens offer improved prospects of tumour remission, deaths from other causes will assume a greater importance. As such, the possibility that ulceration in the gastric tube may be due to causes other than tumour recurrence deserves greater recognition.

Adenocarcinoma↗
PubMed1993

Multiple sclerosis susceptibility: population and twin study of polymorphisms in the T-cell receptor beta and gamma genes region. French Group on Multiple Sclerosis.

Multiple sclerosis (MS) is a demyelinating auto-immune disease of the central nervous system with a suspected genetic component. Previous publications have demonstrated that MS susceptibility is influenced by Major Histocompatibility Complex (MHC) genes and recent studies have focused on additional susceptibility genes. The accumulation of activated T-cells in demyelinating MS lesions, the possible auto-immune mechanism of this disease and the functional relationship between MHC and T cell receptor (TCR) molecules support the hypothesis that TCR genes are good candidates to influence MS development. Published results in this domain are conflicting and still a matter of controversy. In the present study we analysed the influence of V beta, C beta, P lambda G3 and V gamma gene polymorphisms defined by Restriction Fragments Length Polymorphism (RFLP) on 48 pairs of monozygotic and dizygotic twins with at least one of each pair affected, and also in 63 unrelated MS patients for V gamma gene polymorphism. These results have been compared with those in the non affected twins and with data from a control group (Beall et al., 1989) regarding C beta and V beta polymorphisms and with a local control population for V gamma. No significant correlation between C beta, V gamma or P lambda G3 polymorphisms and MS was found, only a non significant tendency to reduced P lambda G3 allele sharing among dizygotic non concordant twin pairs was observed. However one V beta 11, 25 kb allele and a haplotype defined by V beta 11 and C beta alleles showed a correlation with MS susceptibility of borderline significance.(ABSTRACT TRUNCATED AT 250 WORDS)

Alleles↗
PubMed1992

Interrelation of left ventricular ejection fraction, pulmonary congestion and outcome in acute myocardial infarction.

The interrelation of different grades of pulmonary congestion evaluated by chest roentgenogram in the coronary care unit, predischarge left ventricular (LV) ejection fraction (EF) and long-term prognosis was studied in 1,850 surviving patients of acute myocardial infarction (AMI). Pulmonary congestion was categorized as: none, mild or moderate, or severe; LVEF was classified as: greater than or equal to 40%, 25 to 39%, or less than 25%. The majority of patients (1,060; 57%) had an LVEF greater than or equal to 40% and no signs of pulmonary congestion. Severe pulmonary congestion was noted in 63 patients (3.4%), 17 with LVEF less than 25% and 16 with LVEF greater than or equal to 40%. One hundred twenty-five patients (6.8%) had an LVEF less than 25%, 49 of whom had no signs of pulmonary congestion. During a mean 2-year follow-up, cardiac mortality occurred in 212 patients (11.5%). The cardiac mortality rate was related to both predischarge LVEF impairment and severity of pulmonary congestion. Cardiac mortality hazard ratios (95% confidence intervals [CI]) for LVEF less than 25%, and 25 to 39% were 5.32 (CI 3.49, 8.13; p less than 0.0001) and 2.91 (CI 2.10, 4.02; p less than 0.0001), respectively, where a referent hazard ratio of 1 was assigned to patients with LVEF greater than or equal to 40% and to those with no pulmonary congestion. Development of pulmonary congestion during AMI significantly increased the cardiac mortality risk derived from LVEF, with a marked mortality effect in patients with severe pulmonary congestion; (hazard ratio 4.20; 95% CI 2.67, 6.62; p less than 0.0001).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

Markers of dopamine metabolism in Parkinson's disease. The Parkinson Study Group.

We used two analytic methods (a multichannel coulometric electrode array with high-performance liquid chromatography, and gas chromatography-mass spectrophotometry) to measure CSF dopamine (DA) and its metabolites in mildly affected, unmedicated subjects with Parkinson's disease (PD). The mean (+/- SD) concentration of homovanillic acid (HVA), the most abundant product of DA turnover, was 164.57 +/- 95.05 nM. As sequential aliquots of CSF were collected from the first to 23rd ml, CSF HVA concentration almost doubled. After HVA, 3-O-methyldopa (3-O-MD) was the next most abundant compound. The summed concentrations of 3-O-MD, 3,4-dihydroxyphenylacetic acid, 3-methoxytyramine, DA, DA-3-sulfate, homovanillol, and levodopa (LD) amounted to 12.6% of HVA. Concentrations of the DA metabolites did not correlate to a variety of indices of PD severity. The presence of LD and 3-O-MD may be indicators of DA synthesis and possibly could reflect compensatory processes among surviving dopaminergic neurons of the PD brain.

Aged↗
PubMed1991

Photooxidation of specific residues in alpha-crystallin polypeptides.

Singlet oxygen is a biologically important, photochemically generated species that preferentially oxidizes His, Trp, and Met residues of protein molecules. Calf alpha-crystallin was photooxidized with use of meso-tetra(p-sulfonatophenyl)porphyrin (TPPS) and uroporphyrin (UP) as singlet oxygen generators. The effects of photooxidation were monitored by analyzing the changes in alpha-crystallin peptide maps obtained by reversed-phase HPLC using a photodiode array absorbance detector. The reaction led to the loss of six specific peptides, five of which contained photooxidizable residues. Peptides containing His-97 and His-154 from the A chain and Met-68 from the B chain are preferentially photooxidized, suggesting that those residues have access to singlet oxygen. Trp residues in the N-terminal region are converted to NFK, whereas Trp-60 in the B chain is not photooxidized strongly suggesting that the former are close to the surface of alpha-crystallin while the latter Trp residue is buried. Only one peptide that is lost from the peptide maps does not contain a photooxidizable group; however, this peptide does contain an apparently undigested Lys residue. It is suggested that it forms a cross-link with a photooxidized His residue.

Amino Acid Sequence↗
PubMed1991

Effects of diltiazem on long-term outcome after acute myocardial infarction in patients with and without a history of systemic hypertension. The Multicenter Diltiazem Postinfarction Trial Research Group.

The effect of diltiazem on long-term outcome in patients with acute myocardial infarction with and without a history of systemic hypertension was investigated in 2,466 patients using the Multicenter Diltiazem Postinfarction Trial data-base. The baseline variables were comparable in the diltiazem and placebo-treated patients within the groups with and without hypertension. The initial 60-mg dose of diltiazem was associated with a significant (p less than 0.001) but modest (3%) reduction in blood pressure and heart rate in both groups with and without hypertension. Univariate and multivariate analyses revealed a meaningful overall reduction in first recurrent cardiac events (cardiac death or nonfatal reinfarction, whichever occurred first) and cardiac death in patients with hypertension treated with diltiazem compared with results in those treated with placebo. Similar effects were not observed in patients without a history of hypertension. When first recurrent cardiac events were used as the end point, the diltiazem:placebo hazard ratio (95% confidence limits) was 0.77 (0.58, 1.01) for the total hypertension group, and 0.67 (0.47, 0.96) and 1.32 (0.83, 2.10) for patients with hypertension with and without pulmonary congestion during the acute infarction, respectively. Similar results were observed using cardiac death as the end point. Beta blockers had a negligible effect on the hypertension-diltiazem relation. These findings suggest that diltiazem may exert a long-term beneficial effect in most patients with hypertension who do not have pulmonary congestion during an acute infarction, and a detrimental effect in the minority who have pulmonary congestion.

Adult↗
PubMed1991

Indirect measures of memory in a duration-judgement task are normal in amnesic patients.

Nine amnesic patients of mixed aetiology were studied in a duration-judgement task that allowed three measures of memory to be obtained. On each trial of the task, subjects attempted to read a briefly flashed word and to estimate the duration of the flash. Both word identification and duration estimation differed as a function of prior study. Words that were previously studied were identified more often and were estimated to have been flashed for a longer duration than were words not previously studied. These priming effects were found in young subjects in Experiment 1 and in amnesic patients and age-matched control subjects in Experiment 2. Priming effects were normal in the amnesic patients, whereas these patients were severely impaired at recognizing the same words. Previous results have also shown that amnesic patients can perform normally on certain memory tests, including priming of word identification. These results show that priming of duration judgements can also be included in the category of indirect measures of memory that are spared in amnesia.

Adult↗
PubMed1991

Effects of intraocular irrigants on the preserved human corneal endothelium.

Either a simple balanced salt solution (BSS) or a bicarbonate-buffered, glutathione-containing commercial irrigant (BSS Plus, Alcon Laboratories, Fort Worth, Texas, U.S.A.) may be used during the vitrectomy portion of a corneal transplant procedure. To simulate the conditions present in the anterior chamber during the first few hours after vitrectomy and grafting, we performed in vitro perfusions of stored human corneas using each irrigant and measured corneal thickness over a 3-hour period. Irrespective of the preservation medium used (McCarey Kaufman, Chondroin Sulfate or Dexsol, all from Chiron Ophthalmics, Irvine, California) or duration of storage (2 or 4 days), corneas irrigated with BSS Plus exhibited significantly (p less than .05) decreased thickness compared with their paired mates irrigated with BSS. In ultrastructural studies performed on postperfusion corneas, there was a tendency toward improved surface morphology in the in vitro BSS Plus-perfused tissue. This study shows that in vitro corneal thickness after preservation is significantly irrigant dependent, with BSS Plus providing the essential ingredients to promote the corneal endothelial pump function.

Corneal Edema↗