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Biomedical subjects

L Hume

Publications and source records attributed to L Hume.

13 recordsLinked to original sources
PubMed2006

Immune responses to Staphylococcus aureus and Psoroptes ovis in sheep infected with P. ovis--the sheep scab mite.

In sheep, lesions caused by Psoroptes ovis, the sheep scab mite, may become colonized by Staphylococcus aureus. The present study compares clinical signs, lesional area and the immune response to P. ovis and S. aureus in P. ovis-infested sheep with and without secondary S. aureus infection. No differences were detected in the clinical signs or lesional areas in the S. aureus-positive and -negative sheep. However, 6 weeks after infestation an IgG but not IgE isotype antibody response to S. aureus was detected in the S. aureus-positive but not the S. aureus-negative group of sheep. This response targeted S. aureus antigens with molecular weights of approximately 36, 38, 50 and 65 kDa. In addition, 6 weeks after infestation an IgE response to P. ovis was detected in the S. aureus-positive but not the S. aureus-negative group of sheep.

Animals↗
PubMed1995

Battering in pregnancy: an assessment of two screening methods.

OBJECTIVE: To compare two different screening techniques for identifying women with a history of domestic violence or battering in the current pregnancy. METHODS: The five-question Abuse Assessment Screen was incorporated into routine social service interviews and applied prospectively to all registrants for routine prenatal care at Women & Infants' Hospital during an initial social service evaluation from September 7 through October 29, 1993. This group (N = 143) was compared to a historical control group of all new registrants from July 12 through September 3, 1993 (N = 191) who had routine interviews by social services. Demographic and medical data were compared, as well as the specific information addressed by the screen, including history of domestic violence, physical or sexual violence within the last year, violence during the current pregnancy, recent sexual abuse, and fear of partner. RESULTS: The median age of the study population was 23 years old, 50% were white, 63% were single, and 42% had no insurance. There was a higher detection of violence in all categories using the Abuse Assessment Screen compared with the standard interview--any history: 41 versus 14% (relative risk [RR] 3.0, 95% confidence interval [CI] 2.0-4.5); recent history: 15 versus 3% (RR 5.6, CI 2.2-14.5); during pregnancy: 10 versus 1% (RR 9.3, CI 2.2-40.5); recent sexual abuse: 4 versus 0% (P = .006); and fear of abuser: 6 versus 3% (RR 1.8, CI 0.6-5.0). CONCLUSION: Use of a structured screen improves detection rates of battering both before and during pregnancy, enabling clinicians to have a greater opportunity to intervene.

Adult↗
PubMed1985

Potentiation of hypotensive effect of debrisoquine by insulin.

A 36-year-old man who had been an insulin-dependent diabetic for 27 years developed severe postural hypotension only when taking debrisoquine and a short-acting insulin. Hourly recordings of lying and standing blood pressure after an oral dose of debrisoquine in the presence and absence of short-acting insulin confirmed an interaction between the drugs causing symptoms of postural hypotension which may be confused with hypoglycaemia.

Adult↗
PubMed1980

Autonomic mechanisms in the initial heart rate response to standing.

Autonomic mechanisms underlying the initial heart rate response to standing were analyzed in nine normal subjects. The normal pattern of response was altered by atropine to a small and gradual R-R interval shortening over 30 beats, with no rebound R-R interval lengthening. With additional propranolol, R-R interval shortening was even less and confined to the first 15-20 beats, whereas propranolol alone did not affect the normal response pattern, showing that this is under vagal control with increased cardiac sympathetic activity occurring only if the vagus is blocked. The response was reproducible in 23 normal subjects. Heart rate variation during quiet standing was almost completely abolished by atropine, but unaffected by propranolol, confirming that it is also under vagal control. In four normal subjects no rebound R-R interval lengthening occurred during either "fast" or "slow" tilt, whereas it was present during both "slow" and "fast" standing. The rebound R-R interval lengthening is determined by the muscular activity involved in standing up, rather than by the speed of the maneuver.

Adult↗
PubMed1979

Non-invasive assessment of left ventricular response to Valsalva manoeuvre in normal and diabetic subjects using praecordial accelerocardiography.

The left ventricular response to the Valsalva manoeuvre was studied in 5 normal subjects (group 1), 6 diabetics without autonomic neuropathy (group 2), and 5 diabetics with autonomic neuropathy (group 3), using the maximum amplitude of the praecordial accelerocardiogram (DE) as a noninvasive index of left ventricular performance. During the Valsalva manoeuvre DE decreased in all 3 groups. In groups 1 and 2, DE increased significantly above the control value after release of the manoveuvre (DE overshoot) but this did not occur in group 3. It is suggested that the overshoot of DE in groups 1 and 2 reflects an increase in left ventricular contractility after release of the Valsalva manoeuvre and the absence of an overshoot in DE in the patients with autonomic neuropathy is the result of loss of cardiac adrenergic innervation. The ability to detect an abnormal cardiovascular response to the Valsalva manoeuvre using the non-invasive technique of praecordial accelerocardiography may be of practical value in the assessment of left ventricular function.

Adult↗
PubMed1978

The effects of exercise on the amplitude of the first heart sound in normal subjects.

The cardiovascular responses to isometric and dynamic exercise have been studied in six normal subjects, before and after intravenous propranolol, using the amplitude of the first heart sound (S1), measured from an ultra-low frequency phonocardiogram, as an index of left ventricular mechanical performance. Dynamic exercise caused significant increases in heart rate and S1 amplitude which were largely inhibited by beta-adrenergic blockade. Isometric exercise also produced increases in heart rate and blood pressure, but a decrease in S1 amplitude. Propranolol had no significant effect on the cardiovascular response to isometric exercise. These results confirm previous suggestions that, in contrast to dynamic exercise, the normal cardiovascular responses to isometric exercise are relatively independent of the beta-adrenergic nervous system. Possible reasons why the improvement in left ventricular performance, which has previously been shown to occur during isometric handgrip, was not reflected in the phonocardiogram, are also discussed.

Adult↗
PubMed1976

Correlation between praecordial accelerocardiogram and left ventricular pressure.

The praecordial accelerocardiogram possesses important practical advantages over more familiar techniques of recording praecordial pulsations. We have compared the amplitude of the P wave of the praecordial accelerocardiogram in 6 normal subjects (group 1) and 21 patients with heart disease (group 2) at rest and after 3 minutes of isometric handgrip at 30 per cent maximum voluntary contraction. At rest in group 2 there was a significant linear correlation between the amplitude of the P wave of the accelerocardiogram, relative to the maximum systolic amplitude (P/DE), and the left ventricular end-diastolic pressure (P less than 0-01). However, comparison of the data for P/DE showed that the mean value (+/-SEM) of 29+/-5 per cent in group 1 was not significantly different from the mean value of 37+/-4 per cent in group 2 (P g .reater than 0-30). During handgrip the mean amplitude of the P wave did not increase significantly in group 1 (P greater than 0-20) but increased significantly in group 2 (P less than 0-02). In group 2 there was a significant linear correlation between the percentage increase in the amplitude of the P wave of the accelerocardiogram during handgrip and the percentage increase in the left ventricular end-diastolic pressure (P less than 0-01).

Adult↗
PubMed1975

Effects of sustained isometric handgrip on praecordial accelerocardiogram in normal subjects and in patients with heart disease.

The effects of isometric exercise on the maximum amplitude of the praecordial accelerocardiogram (as represented by the DE deflection) have been compared in 6 normal subjects (group 1), 12 patients with aortic stenosis (group 2), and 16 patients with myocardial disease (group 3). Whereas the tachycardia and pressor effects of isometric exercise were identical in all three groups, the normal subjects showed a significant decrease in DE during handgrip of 10 +/- 4 per cent (P less than 0.05) as compared with the insignificant increases of 8.5 +/- 6 per cent (P greater than 0.5), and 4 +/- 3.5 per cent (P greater 0.3) observed in the patients in groups 2 and 3. This response in the normal subjects differed significantly from the responses observed in the patients in groups 2 (P less than 0.02) and 3 (P less than 0.01). Of the patients in each of groups 2 and 3, 50 per cent responded abnormally to handgrip in that they showed a significant increase in DE. In the patients with aortic stenosis this subgroup of patients differed from the remainder in that they had a higher resting cardiac index (P less than 0.05). In the patients with myocardial disease this subgroup was characterized by a significantly lower resting left ventricular end-diastolic pressure (P less than 0.02). It seems, therefore, that those patients who increase DE in response to handgrip tend to have better left ventricular function at rest than those who do not. We suggest that this may be because of increased beta adrenergic activity at rest and during isometric exercise in the subgroup who respond to handgrip with an increase in DE.

Adult↗
PubMedDate not supplied

Ambulatory monitoring of the ST segment in diabetic men with and without peripheral neuropathy.

To assess whether myocardial ischaemia is more common in diabetic patients with neuropathy, 24-hour ambulatory monitoring of the ST segment was performed on 27 diabetic men without peripheral neuropathy and in 28 with neuropathy. The patients were matched for age 54 +/- 7 years (mean +/- SD) versus 54 +/- 7 years and for duration of diabetes (16 +/- 9 years versus 16 +/- 12 years). None had clinical evidence of heart disease. Episodes of ST segment depression were seen during ambulatory monitoring in 12 diabetics (22%) but were not more common in patients with peripheral neuropathy. Four of the 13 diabetics with autonomic neuropathy had ST depression during ambulatory monitoring. During a median follow-up period of 50 months, four patients developed clinical heart disease. Three of these patients had shown ST depression during ambulatory monitoring. ST depression during ambulatory monitoring is common in diabetic men without cardiac symptoms but is not related to the presence of peripheral neuropathy. Diabetics with ST depression during ambulatory monitoring are at increased risk of developing heart disease in subsequent years.

Coronary Disease↗
PubMedDate not supplied

Provocation of postural hypotension by nitroglycerin in diabetic autonomic neuropathy?

The effect of nitroglycerin on heart rate and systolic blood pressure was compared in 5 normal subjects, 12 diabetic subjects without autonomic neuropathy, and 5 diabetic subjects with autonomic neuropathy. The magnitude and time course of the increase in heart rate and the decrease in systolic blood pressure after nitroglycerin were similar in the normal and diabetic subjects without autonomic neuropathy, whereas a lesser increase in heart rate and a greater decrease in systolic blood pressure occurred in the diabetic subjects with autonomic neuropathy. It is therefore suggested that caution should be exercised when prescribing vasodilator drugs in diabetic patients, particularly those with autonomic neuropathy.

Adolescent↗
PubMedDate not supplied

Asymptomatic myocardial ischemia in diabetes and its relationship to diabetic neuropathy: an exercise electrocardiography study in middle-aged diabetic men.

The incidence of painless ischemic heart disease is increased in diabetic patients, and it has been suggested that this may be partly due to diabetic neuropathy involving cardiac afferent nerves. We have performed exercise electrocardiography in middle-aged diabetic men without cardiac symptoms to see if silent myocardial ischemia is more common in patients with neuropathy. Thirty patients had diabetic neuropathy (group 1), and 30 did not (group 2). The groups were matched for age and duration of diabetes. The exercise test was abnormal in 14 patients. A positive test was no more common in patients with diabetic neuropathy. During a mean follow-up period of 50 mo, five patients developed clinical heart disease, four of whom had a positive exercise test. An abnormal exercise ECG is common in diabetic men without cardiac symptoms, but our study does not suggest that the high incidence of silent myocardial ischemia in diabetic patients is related to the presence of diabetic neuropathy. In patients with diabetes a positive exercise test is associated with a high risk of developing clinical heart disease in subsequent years.

Adult↗