Search PubMed⌕ Search

Biomedical subjects

G Ambrosio

Publications and source records attributed to G Ambrosio.

156 records · Page 9Linked to original sources
PubMedDate not supplied

Measuring contrast sensitivity in aretinopathic patients with Insulin Dependent Diabetes Mellitus.

Contrast sensitivity measurements were obtained from 66 patients with Insulin Dependent Diabetes Mellitus (IDDM) and no visible diabetic retinopathy (Group A, n = 30 prepubescent and pubescent subjects; Group B, n = 36 postpubescent subjects). Contrast thresholds were determined for stationary and 6.87 Hz phase-alternating gratings at eight spatial frequencies from 0.18 to 15.7 c/deg. Data from each group of diabetic patients was compared with data from puberty-matched normal subjects. Mean value of the last four determinations of glycohemoglobin Alc (HbAlc) was used as a index of glycemic control. We found that patients with IDDM and no retinopathy had normal contrast sensitivity and that contrast thresholds were not significantly related to sexual maturity, duration of diabetes and glycemic control.

Adolescent↗
PubMedDate not supplied

Mepindolol reduces myocardial necrosis in rats with coronary artery occlusion.

Mepindolol is a newly developed beta-adrenergic blocking agent reported to counteract the chronotropic effect of catecholamines, with only little effect on contractility. This study was designed to assess whether or not mepindolol is effective in reducing infarct size. Accordingly, 16 rats, serving as controls, underwent coronary artery occlusion and did not receive any treatment; an additional 19 were treated with mepindolol (1 mg/kg s.c. t.i.d.) for 48 h. Finally, a third group (n = 18) underwent sham operation. Forty-eight hours later, infarct size was calculated from left ventricular creatine phosphokinase activity and found to average 52.4 +/- 7.8% (mean +/- SEM) of the left ventricle in control rats and 35.6 +/- 5.4% in treated rats (p less than 0.05). Left ventricular phospholipid content averaged 0.79 +/- 0.08 microgram P/mg protein in sham-operated rats and 0.61 +/- 0.04 microgram P/mg protein in control animals. In contrast, in mepindolol-treated rats, phospholipid concentration was 0.70 +/- 0.04 microgram P/mg protein (p less than 0.05), this suggesting a protective effect of the drug on ischemia-induced phospholipid degradation. The long-term effect of mepindolol on left ventricular hydroxyproline concentration was assessed 21 days post-coronary occlusion. Infarct size calculated by this method was 30.2 +/- 4.8% of left ventricle in 21 control animals and 18.2 +/- 4.2% in 28 treated rats (p less than 0.05), indicating that, as for the acute necrosis, the extent of scar development after coronary artery occlusion can be reduced by mepindolol.

Adrenergic beta-Antagonists↗
PubMedDate not supplied

Increased low-density lipoprotein peroxidation in elderly men.

BACKGROUND: Oxidative modification of low-density lipoprotein (LDL) appears to play a pivotal role in atherogenesis. The specific role played by LDL peroxidation in aging is not known. Since estrogens may protect LDL from peroxidation in vitro and in vivo, we chose to investigate only men of various ages. OBJECTIVE: To determine whether LDL from healthy elderly men was differently susceptible to peroxidation than LDL of young and adult men. SUBJECTS AND METHODS: LDL was isolated from 15 normolipidemic young (aged 19-23 years), 17 adult (aged 35-55 years), and 16 elderly (aged 77-90 years) healthy men. None of the men included in the study was a smoker or a hypertensive. LDL peroxidation was achieved by exposure to 5 mumol/l copper sulfate for 18 h at 37 degrees C, and some markers of lipid peroxidation (estimating various levels of peroxidation) were evaluated. RESULTS: The levels of lipid peroxides in LDL from our elderly men were already higher under basal conditions than were those both of adult and of young men. LDL from elderly men was more susceptible to peroxidation than was that of adult and young men. Furthermore, the lag time correlated inversely to age (r = -0.68, P < 0.01), whereas lipid peroxide and malonyldialdehyde levels correlated highly to age (r = 0.79 and r = 0.77, P < 0.0002 and P < 0.0012, respectively). With aging the vitamin E content in LDL decreased whereas the arachidonic fatty acid content increased. More importantly, the relationship between the vitamin E content and the lag time made evident the parallel increase in lag time and in vitamin E level with aging. The vitamin E concentration also correlated inversely to levels of thiobarbituric acid-reactive substances in LDL from elderly patients (r = -0.61, P < 0.05). CONCLUSIONS: The present study shows that LDL peroxidation increases with age. This phenomenon may favor the progression of atherosclerosis in elderly men.

Adult↗
PubMedDate not supplied

[Evaluation of the effects of occupational noxae on the cardiovascular system].

BACKGROUND: Working conditions and the environment may contribute to the multi-factorial aetiology of cardiovascular disease. OBJECTIVES: To provide a critical assessment of epidemiological and clinical methods and tools for evaluating the effects of occupational pathogenic noxae on the cardiovascular system. METHODS: A review was made of epidemiological and clinical studies published in the main scientific journals of occupational medicine and cardiology, in the period 1980-2003. Data sources were electronic medical data bases and conference proceedings. RESULTS AND CONCLUSION: Collecting case histories by means of free or questionnaire-structured interviews, observing specific physical signs, detecting changes in blood chemistry parameters and identifying morphological or functional abnormalities in the heart and vessels are all useful approaches. Some blood chemistry parameters that may be modified by occupational exposure or by particular conditions arising from work organization are cholesterol, triglycerides, apolipoproteins A and B, platelets, fibrinogen, factor VIIc, fibrinolysis products, plasminogen tissue activating factor, complement and glycated hemoglobin. They can all be measured easily and quickly and provide an estimate of the risk of cardiovascular disease. As high blood pressure is closely correlated to heart disease, blood pressure levels can be monitored in a working population using a standard mercury sphygmomanometer. Electronic measurement before and after a work shift and 24 hour Holter monitoring help reduce the "white coat effect" and provide further useful information. Occupational risk factors such as toxins (metals, solvents, pesticides), electromagnetic fields, extreme temperatures, noise, radiation and psychophysical stress can affect the cardiac neuro-autonomic balance of the exposed workers and cause cardiovascular abnormalities. These can be detected by long-term ECG monitoring, and are revealed as reduced heart rate variability and prolonged QT interval. Recently non-invasive systems have been adopted to detect cardiovascular lesions that are usually due to atherosclerosis. In occupational and environmental studies ultrasound measurement of intima-medial carotid thickness and brachial artery reactivity have been used to determine the effects of exposure to carbon disulfide and passive smoking. Occupational Medicine has yet to include the use of the very expensive electron-beam computed tomography for a rapid and non-invasive study of coronary artery disease.

Arrhythmias, Cardiac↗
PubMedDate not supplied

Effects of oral salt load on arginine-vasopressin secretion in normal subjects.

Arginine-vasopressin (AVP) plays an important role in regulating water balance in humans. Its secretion is under control of several mechanisms, some of which are not completely understood. The purpose of the present study was to evaluate the effects of an acute oral salt load on AVP secretion in normal subjects. Six normal volunteers received 350 mEq of NaCl per os. Pulmonary capillary wedge pressure and right atrial pressure, plasma AVP, plasma sodium and potassium concentration, plasma osmolality, hematocrit, urinary sodium and potassium excretion, and urinary flow were measured at baseline and every 30 minutes for two hours after the salt load. Hemodynamics as well as urinary sodium and potassium excretion did not change over the study. Ninety minutes after the salt load, plasma AVP increased from the basal value of 6.0 +/- 0.9 pg per ml to 10.1 +/- 1.2 pg per ml (mean +/- SE, p less than 0.005) and a significant reduction in diuresis of about 50% was observed. However, plasma osmolality and plasma sodium concentration increased significantly only 120 min after the salt load, from the initial value of 277.7 +/- 2.2 mOsm per kg and 145.3 +/- 1.4 mEq per 1 (mean +/- SE) to 284.8 +/- 2.5 mOsm per kg and 148.7 +/- 1.5 mEq per 1, respectively (p less than 0.01). Ninety minutes after the salt load, no correlation was found between plasma osmolality and plasma AVP concentration, indicating that AVP secretion was independent of changes in systemic blood osmolality.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMedDate not supplied

[Dental amalgam].

Explore the source record for details and available documents.

Biocompatible Materials↗
PubMedDate not supplied

[Epulis].

Explore the source record for details and available documents.

Adult↗
PubMedDate not supplied

Visual function before and after photorefractive keratectomy for myopia.

BACKGROUND: To date, Snellen visual acuity and postoperative refraction have been used to evaluate the results of photorefractive keratectomy. However, other parameters, such as contrast sensitivity function and glare, may be affected by refractive surgery and lead to unsatisfactory visual performance. This prospective study is aimed at evaluating the effect of photorefractive keratectomy on contrast sensitivity function and glare. SUBJECTS AND METHODS: Static contrast sensitivity function, dynamic contrast sensitivity function, and glare sensitivity were evaluated in 22 myopic eyes before as well as 1, 3, and 6 months after photorefractive keratectomy. The eyes tested were divided into three groups, according to the amount of myopia: group I, from -4.00 to -8.00 diopters (D); group II, from -8.25 to -11.00 D; group III, from -11.25 to -20.00 D. RESULTS: Both static and dynamic contrast sensitivity function at the intermediate spatial frequencies were altered at 1 month after photorefractive keratectomy, with a trend toward recovery at 3 and 6 months postoperatively. Glare sensitivity was not significantly affected by surgery. CONCLUSIONS: Contrast sensitivity function and glare testing may show abnormalities in the presence of optimal visual and refractive results. These tests may result especially important for the evaluation of new refractive surgical procedures.

Adolescent↗