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Biomedical subjects

P Collins

Publications and source records attributed to P Collins.

At least 181 records · Page 10Linked to original sources
PubMed1995

Insulin resistance syndrome in postmenopausal women with cardiological syndrome X.

OBJECTIVE: To determine whether postmenopausal women with cardiological syndrome X (chest pain and abnormal exercise electrocardiogram despite normal coronary angiography) exhibit disturbances in the full range of proposed components of the putative "insulin resistance syndrome". PATIENTS AND METHODS: 20 postmenopausal women with syndrome X and 20 healthy controls each underwent measurement of insulin resistance (by minimal model analysis of the intravenous glucose tolerance test), lipid, lipoprotein, and apolipoprotein concentrations, a range of haemostatic variables, serum uric acid concentration, and centrality of body fat distribution (by dual energy x ray absorptiometry). RESULTS: Women with syndrome X had higher fasting triglyceride concentrations than controls (median: 1.60 v 1.02 mmol/l, P < 0.05). Concentrations of high density lipoprotein cholesterol were lower (1.33 v 1.61 mmol/l, P < 0.05) as were those of the high density lipoprotein apolipoproteins AI and AII. Insulin and C peptide responses to the intravenous glucose tolerance test were higher (27.6 v 19.8 microU/ml/min, P < 0.01; 101 v 72 pmol/ml/min, P < 0.05, respectively), and insulin sensitivity was lower (1.89 v 3.09 min/microU/ml, P < 0.05). There were, however, no significant differences between other proposed components of the insulin resistance syndrome (blood pressure, glucose tolerance, proportion of central body fat, serum uric acid concentration, and plasminogen activator inhibitor-1 activity). Antithrombin III activity was higher in women with syndrome X (121 v 113%, P < 0.01). CONCLUSIONS: Women with syndrome X tend to be insulin resistant and have lipid and lipoprotein abnormalities, but do not exhibit all characteristics of the insulin resistance syndrome. Such variation in correlated risk factors is consistent with underlying heterogeneity in the insulin resistance syndrome and cardiological syndrome X.

Aged↗
PubMed1995

Significant differences between side-mounted and end-mounted intracoronary Doppler flow probes for the measurement of blood flow velocity.

Use of the intracoronary Doppler flow probe is an established method for the assessment of coronary blood flow velocity. The aim of this study was to perform an in vitro comparison of two commonly used Doppler probes, which differ in the location of the piezoelectric crystal (end-mounted vs side-mounted). Blood flow velocity was measured over a wide range of flow rates in a flow simulator using heparinized whole blood. Measurements were made with both Doppler probes assessed in two positions (supported and unsupported) within the tubing. The results were compared with estimated true velocities. Further measurements were made with six side-mounted probes, correcting for the assumed crystal mounting angle and for the angle calculated from magnified images of the individual crystals. Mean velocities for end- and side-mounted probes correlated highly with predicted velocities (all r > or = 0.99), but the side-mounted probes significantly overestimated velocity by > 100%. Estimation of the true crystal mounting angle of the side-mounted probe revealed considerable variability (range 30-42 degrees) and was lower than the recommended angle correction factor of 60 degrees. Velocities corrected for the individual crystal mounting angles agreed more closely with predicted mean velocities. Although both probes are adequate for the assessment of relative changes in flow, the side-mounted probe considerably overestimates mean velocity, which is partly explained by the variable mounting angle of the crystal. The demonstrated limitations of the side-mounted Doppler flow probe in vitro should be considered in undertaking measurement of intracoronary blood flow velocity.

Analysis of Variance↗
PubMed1995

Serum angiotensin-I-converting enzyme activity in women with cardiological syndrome X: relation to blood pressure and lipid and carbohydrate metabolic risk markers for coronary heart disease.

Polymorphism of the angiotensin-I-converting enzyme (ACE) gene is associated with variations in serum ACE activity and the incidence of cardiovascular disease. Whether a similar association exists with cardiological syndrome X (chest pain, positive ECG exercise test, and normal angiography) is unclear. As ACE activity affects vascular tone, it could be involved in the pathogenesis of this syndrome. We measured serum ACE activity in 18 postmenopausal women with syndrome X and in 18 healthy controls matched for age, adiposity, and menopausal status. The relationship of ACE activity to coronary heart disease risk factors was also examined within these groups. Serum ACE activity did not differ significantly between women with syndrome X and controls. Neither blood pressure, serum total cholesterol, triglyceride, nor high density lipoprotein subfraction 2 cholesterol was associated with ACE activity in either patient group. However, serum high density lipoprotein cholesterol, high density lipoprotein subfraction 3 cholesterol, and apolipoprotein-A-I and -A-II were inversely associated with ACE activity in women with syndrome X, but not in controls. Insulin sensitivity, fasting plasma glucose, insulin, and C-peptide as well as their postglucose challenge concentration profiles were not significantly associated with ACE activity in either group. We conclude that serum ACE activity and, consequently, ACE polymorphism are not associated with syndrome X and are largely independent of metabolic risk factors in these women.

Angiotensin I↗
PubMed1995

Elevated levels of lipoprotein (a) in association with cerebrovascular saccular aneurysmal disease.

The relationship between cerebrovascular aneurysmal disease and atherosclerosis remains unclear. Elevated serum levels of lipoprotein (a) (Lp[a]), are an independent risk factor for atherosclerosis. We measured serum Lp(a) levels in 50 patients who had angiographically proven saccular aneurysmal disease and who were free of clinically significant atheromatous disease (as judged by their medical histories and the results of physical examination, electrocardiography, and carotid angiography). The Lp(a) serum levels in these patients were compared with the Lp(a) serum levels in a group of 42 normal healthy controls. Serum Lp(a) levels in the patients was 20.1 +/- 0.42 mg/dl (median +/- standard error); however, median serum Lp(a) in the control subjects was 10.8 +/- 0.47 mg/dl (P < 0.01). Among females, the difference in serum Lp(a) levels was significant; the levels were 22.2 +/- 0.6 for female patients (n = 29) and 9.5 +/- 0.53 in female control subjects (n = 26) (P < 0.005). The most significant difference (P < 0.002) was seen in females < 50 years old (14 patients, 10 control subjects). No significant differences were seen in the Lp(a) serum levels between 21 male patients and 16 male control subjects. Lp(a) levels above the threshold level (30 mg/dl) were found in 20 patients and 7 control subjects (chi 2 = 5.99, P < 0.02); 12 female patients and 3 female control subjects (chi 2 = 6.16, P < 0.02; 8 male patients and 4 male control subjects (this difference was not significant). These results indicate either that cerebrovascular aneurysmal disease and subclinical atherosclerosis are related or that Lp(a) is a risk factor for vasculopathies other than atheroma.

Adult↗
PubMed1994

Abnormal autonomic control of the cardiovascular system in syndrome X.

Anomalies of autonomic control of the coronary circulation may play a role in the development of syndrome X (angina pectoris, ischemic-appearing results on exercise test, and normal coronary arteriograms). Twenty-six patients with syndrome X and 20 healthy sex- and age-matched control subjects were studied by means of analysis of heart rate variability during 24-hour Holter monitoring. Spectral and nonspectral parameters of heart rate variability were investigated. Mean heart rate was similar in patients with syndrome X and in control subjects. Patients with syndrome X had significantly lower standard deviation of all normal RR intervals, a lower percentage of adjacent normal RR intervals > 50 ms in difference (126.4 +/- 22 vs 149 +/- 43 ms, p < 0.05; 6.3 +/- 4 vs 11.2 +/- 7%, p < 0.05; respectively), and a trend toward lower values of time-domain parameters. Lower values of total power and low frequency were also observed in patients with syndrome X (1273 +/- 693 vs 1790 +/- 989 ms2, p < 0.05; 406 +/- 176 vs 729 +/- 455 ms2, p < 0.01, respectively). An inverse correlation between heart rate and measures of heart rate variability was found in syndrome X but not in control subjects. High- and low-frequency power showed a similar circadian pattern in syndrome X patients and control subjects. Patients and control subjects were then allocated into 2 groups according to the median RR duration: syndrome X1 and control 1 with high mean heart rate, and syndrome X2 and control 2 with low mean heart rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1994

Alterations in apolipoprotein B-48 in the postprandial state in NIDDM.

The intestine is a major site of cholesterol synthesis and produces apolipoprotein B-48, which is critical for intestinal cholesterol absorption and secretion. The purpose of this study was to examine postprandial changes in apolipoprotein B-48 in diabetes. Six non-insulin-dependent diabetic patients and six non-diabetic control subjects were given a high-fat meal (1300 kcal) and blood samples were taken pre- and postprandially, from which the triglyceride-rich lipoprotein fraction was isolated by ultracentrifugation (density < 1.006 g/ml). Apolipoprotein B-48 was separated on 4-15% gradient gels and quantified as a percentage of the fasting concentration by densitometric scanning. Total protein, triglyceride and cholesterol in the triglyceride-rich lipoprotein fraction, blood glucose, and serum insulin were also measured. Diabetic patients exhibited a postprandial triglyceride-rich apolipoprotein B-48 profile significantly different from that of control subjects (p < 0.05). The triglyceride and total protein concentration in the triglyceride-rich lipoprotein fraction mirrored the post-prandial profile and apolipoprotein B-48 in both groups. Significantly different patterns for triglyceride (p < 0.02) and total protein (p < 0.05) following the fat-rich meal were observed in the two groups. Fasting and postprandial triglyceride-rich lipoprotein cholesterol and total apolipoprotein B were significantly higher in diabetic patients than in control subjects (p < 0.05). Since apolipoprotein B-48 is the structural protein of intestinally-derived lipoprotein particles, these studies suggest an abnormality in intestinal lipoprotein metabolism in diabetes.

Apolipoprotein B-48↗
PubMed1994

Epidemiology of motor vehicle crash-related serious eye injuries.

The Eye Injury Registry of Alabama has been collecting epidemiologic, treatment, final outcome, and rehabilitation information on serious ocular trauma since 1982. By December 31, 1989, 150 motor vehicle crash-related eye injuries had been registered. This is the largest series of motor vehicle crash-related serious eye injuries reported. The mean age of those injured was 29 years; 61% were between 16 and 35 years of age, and 73% were males. Ten individuals (7%) suffered bilateral eye injuries. The retina was injured in 47% of eyes. The initial visual acuity was 19/200 or worse (legal blindness) in 47% of eyes. Of eyes with at least 3 months of follow-up, 63% had worse than 20/200 initial visual acuity and 41% remained legally blind. Twelve percent of eyes required removal. Possibly due to the large number of blunt ruptures, motor vehicle crash-related eye trauma carries a particularly unfavorable treatment prognosis. Prevention of these injuries is therefore of extraordinary importance.

Accidents, Traffic↗
PubMed1994

Development and evaluation of an inventory for rating client satisfaction with outcome in HIV counseling: the Albion Center scale.

We developed an inventory for rating client satisfaction with outcome in HIV counseling, based on interview responses with clients. The resulting 19-item scale was subject to factor analysis and four factors, accounting for 56% of the variance, emerged. The factors described dimensions of Perception of progress and improved mood; Recognition of a specific need for counseling; Behavior change from counseling; and Counseling climate. Factor-scored scales were significantly associated with time in counseling and for the Specific need for counseling scale, HIV-seropositive respondents had a significantly higher score. Scale reliabilities (Cronbach's alpha) were between 0.85 and 0.50. Concurrent administration with the Counseling Evaluation Inventory indicated that there were significant correlations between the two scales.

Adult↗
PubMed1994

Biochemical and molecular genetic studies of abdominal aortic aneurysm in an Irish population.

Abdominal aortic aneurysm (AAA) is a common disease of the elderly exhibiting a complex aetiology. In a survey of 82 Irish aneurysm patients, compared to 79 age- and sex-matched control subjects, we have investigated a number of potential biochemical and molecular genetic markers which are amenable to analysis from blood specimens and which might have predictive value for AAA. No significant differences were observed between patients and control subjects in relation to serum lipids, leucocyte elastase activity or serum alpha 1-antitrypsin concentration. We have used the polymerase chain reaction to screen the patient and control groups in search of disease-associated genetic variation on chromosome 16, particularly in the region of the Cholesteryl Ester Transfer Protein (CETP) gene. Although variation in allele frequencies was detected between patients and controls at the four marker loci studied, no significant gene-disease associations were detected. The absence of gene-disease associations in our study may indicate that the genetic component in the aetiology of AAA in Ireland differs from that in the UK. Alternatively, it may indicate that the high degree of polymorphism at microsatellite loci may make them unsuitable as markers for the study of gene-disease associations in moderately sized populations. We therefore conclude that the biochemical and molecular genetic markers which we have examined are of no predictive value, and that ultrasonography remains the screening modality of choice for abdominal aortic aneurysm.

Aged↗
PubMed1994

Dopamine and the structure of personality: relation of agonist-induced dopamine activity to positive emotionality.

Modern trait theories of personality include a dimension reflecting positive emotionality (PE) based on sensitivity to signals of incentive-reward. In animals, responsivity within an emotional system analog of PE is dependent on brain dopamine (DA) activity. To determine whether human PE trait levels are also associated with central DA, effects of a specific DA D2 receptor agonist were assessed in Ss who were widely distributed along the trait dimension of PE. The degree of agonist-induced reactivity in two distinct central DA indices was strongly and specifically associated with trait levels of PE, but not with other personality traits. The results suggest that the trait structure of personality may be related to individual differences in brain DA functioning.

Adult↗
PubMed1994

The Mental Adjustment to HIV scale: measurement and dimensions of response to AIDS/HIV disease.

Attitudes of people with HIV disease towards HIV have seldom been measured. However, a well-established scale to measure attitudes toward cancer in those with the disease, the 38-item Mental Adjustment to Cancer (MAC) scale was modified to assess adjustment to HIV disease. We administered the scale to 107 Australian men with HIV infection, of whom 36 had an AIDS-defining condition, who were patients at an ambulatory care facility and in a research study. The data were factor analyzed using a method identical to that used in the development of the MAC scale to determine the latent dimensions of attitudes toward HIV/AIDS. The Mental Adjustment to HIV scale (MAH) factor analysis revealed five factors: Helplessness-Hopelessness, Fighting Spirit, and Denial-Avoidance as in the original MAC scale, plus a Fatalism subscale which also measured Preoccupation, and a new subscale, which measured Belief in Influencing the Course of the Disease. Together, these five factors accounted for half of the variance. These data suggest that while there are similarities between mental attitude to cancer and mental attitude to HIV in the latent dimensions of the questionnaire items, there are also some differences. Most significant is the belief in people with HIV disease in being able to personally influence the course of the illness, and the combination of Preoccupation with Fatalism. The five subscales of the MAH scale had Cronbach's alpha reliabilities between 0.80 and 0.55. The MAH appears to be a useful way to measure total attitudes and subscale scores of people with HIV infection, including AIDS, to their disease.

Acquired Immunodeficiency Syndrome↗
PubMed1994

The effects of intracoronary substance P and acetylcholine on coronary blood flow in patients with idiopathic dilated cardiomyopathy.

Attenuation of the increase in blood flow caused by acetylcholine in the peripheral vasculature and coronary circulation of patients with heart failure has been interpreted as an impairment of endothelium-dependent vasodilation. The aim of this study was to compare in man the effects of acetylcholine, which also has endothelium-independent actions, with substance P, which appears to be a pure endothelium-dependent vasodilator, on epicardial and resistance coronary arteries in patients with idiopathic dilated cardiomyopathy. The effects of intracoronary acetylcholine (10(-7) M and 10(-6) M) and substance P (5, 10 and 25 pmol.min-1) on epicardial coronary artery diameter and coronary blood flow velocity were measured with an intracoronary Doppler flow probe and quantitative coronary angiography in 11 patients with idiopathic dilated cardiomyopathy and 10 control subjects. Epicardial coronary artery diameter did not change with acetylcholine but increased significantly with substance P in both groups (cardiomyopathy patients: 3.3 +/- 0.2 mm (mean +/- SEM) at baseline vs 3.9 +/- 0.2 mm with substance P25 pmol.min-1, P < 0.01; controls: 3.1 +/- 0.2 mm at baseline vs 3.9 +/- 0.3 mm with substance P25 pmol.min-1, P < 0.05). Coronary flow ratios with acetylcholine were lower in cardiomyopathy patients (10(-7) M: 1.4 +/- 0.1 vs 2.3 +/- 0.4, P = 0.05; 10(-6) M: 1.8 +/- 0.2 vs 3.2 +/- 0.5, P = 0.05 vs controls).(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗
PubMed1994

A survey of the intended management of acute postoperative pain by newly qualified doctors in the south west region of England in August 1992.

A questionnaire designed to assess the knowledge of newly qualified house officers about the management of postoperative pain, was sent to 203 preregistration house officers in the South West region of England. The questionnaire sought information on the following: (1) the prescription of postoperative analgesia for four clinical cases, (2) the use of nonsteroidal anti-inflammatory drugs in patients with six medical conditions, and (3) the management of a patient who had an epidural infusion. The response rate was 26% (54 house officers) and only 13% of those circulated answered all four clinical cases appropriately. The use of nonsteroidal anti-inflammatory drugs was often inappropriate. The management of the patient with a postoperative epidural infusion was inadequate when compared with a minimum safe response protocol designed by the authors. The poor theoretical and practical knowledge demonstrated in this survey indicates that urgent changes are required in the undergraduate curriculum to take account of the recent revolution in the management of severe postoperative pain.

Adolescent↗
PubMed1994

Photoallergic contact dermatitis to oxybenzone.

A 21-year-old woman developed an erythematous papulovesicular eruption of photo-exposed sites, following the use of an oxybenzone-containing sunscreen. Patch testing, photopatch testing, phototesting, and histology produced findings strongly suggestive of oxybenzone photoallergy. Photopatch testing with a monochromator source showed abnormal UVA responses, with evidence of immediate urticaria, and delayed-onset dermatitis. Sun-barrier use is associated with a risk of the development of contact or photocontact allergic reactions. The benzophenones are frequently used in high-protection factor sun-barrier preparations, and appear to have a particular ability to induce such responses.

Adult↗
PubMed1994

Pulmonary sarcoidosis presenting as a granulomatous tattoo reaction.

A 29-year-old man presented with nodular skin lesions localized to areas of navy-blue pigmentation within a tattoo. Light microscopy demonstrated well-defined epithelioid granulomata in close relation to blue and black pigment. Although the patient was asymptomatic, a chest X-ray showed bilateral pulmonary shadowing, and histology of a transbronchial biopsy specimen showed features compatible with a diagnosis of sarcoidosis. X-ray energy dispersive spectroscopy identified copper and titanium in the tattoo pigment. These elements were not found in tissue from the lung biopsy. The cutaneous eruption resolved with oral steroid therapy. Our observations suggest that the granulomatous reaction in the tattoo was a manifestation of sarcoidosis, rather than a specific reaction to pigment.

Adult↗
PubMed1994

Inhibition of hypoxia-induced relaxation of rabbit isolated coronary arteries by NG-monomethyl-L-arginine but not glibenclamide.

1. The effects of NG-monomethyl-L-arginine, tetrodotoxin and glibenclamide on hypoxia-induced coronary artery relaxation, induced by bubbling Krebs solution with 95% N2 and 5% CO2 instead of 95% O2 and 5% CO2, were assessed by measuring the changes in isometric tension in isolated epicardial coronary artery rings of the rabbit. In addition, the effects of glibenclamide on the relaxation induced by adenosine were investigated. 2. Hypoxia caused a transient relaxation of 38 +/- 3% (P < 0.01) and 17 +/- 2% (P < 0.01) in endothelium-intact or -denuded arteries respectively. NG-monomethyl-L-arginine (30 and 100 microM) inhibited the relaxation in endothelium-intact rings to 31 +/- 2% (P < 0.05) and 16 +/- 2% (P < 0.01) respectively and slightly but significantly attenuated the relaxation in endothelium-denuded rings to 15 +/- 1% and 13 +/- 1% (P < 0.05) respectively. 3. Glibenclamide, a potassium channel inhibitor, did not significantly after the hypoxia-induced relaxation. 4. Incubation with tetrodotoxin (3 and 10 microM) for 30 min reduced the relaxation to 31 +/- 3% (P < 0.05) and 14 +/- 2% (P < 0.01), and 14 +/- 2% (P < 0.05) and 11 +/- 1% (P < 0.05) in endothelium-intact and -denuded rings respectively. However, indomethacin (10 microM), atropine (1 microM), propranolol (10 microM) and phentolamine (10 microM) did not significantly affect the relaxation. 5. Adenosine (1, 10 and 100 MicroM) caused relaxation of 6 +/- 1%, 52 +/-3% and 97 +/-2% respectively in endothelium-denuded rings precontracted with prostaglandin F2alpha (PGF2 alpha, 3 MicroM) and the relaxation was markedly inhibited by 8-phenyltheophylline. Furthermore, glibenclamide (1 and 10 MicroM) reduced the relaxation induced by adenosine (1, 10 and 100 MicroM) to 2 +/-1% (P<0.05), 38 =/-3% (P<0.05) and 85 +/-2%(P<0.05), and 0.6 +/- 0.4% (P<0.05), 27 +/- 4% (P<0.05) and 72 +/- 4% (P<0.01) respectively, in these endothelium-denuded preparations.6. These data suggest that hypoxia-induced relaxation is mediated by the release of nitric oxide rather than by the activation of glibenclamide-sensitive potassium channels in rabbit isolated coronary arteries. A neurogenic mechanism partially modulates the relaxation, possibly by activating non-adrenergic and noncholinergic nerve endings. The inhibition by glibenclamide on adenosine-induced relaxation in isolated coronary arteries may help to explain the fact that glibenclamide inhibits hypoxic coronary relaxation in perfused hearts but not in isolated coronary preparations.

Adenosine↗