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Biomedical subjects

A V Greco

Publications and source records attributed to A V Greco.

At least 127 records · Page 7Linked to original sources
PubMed1990

Ultrasound-Doppler diagnosis of Budd-Chiari syndrome.

We report a case of apparently idiopathic Budd-Chiari syndrome, diagnosed by ultrasound and Doppler sonography, in a patient with latent myeloproliferative disease. This case proves that Doppler sonography shows in the hepatic veins a flow pattern suggestive of partial thrombotic obstruction. Moreover, we suggest that the search for a latent myeloproliferative disorder, by means of the spontaneous erythroid colonies formation in culture of bone marrow or blood mononuclear cells, should be routinely included in the diagnostic evaluation of each case of hepatic vein thrombosis without other recognizable causes.

Blood Flow Velocity↗
PubMed1990

Evidence for early impairment of macular function with pattern ERG in type I diabetic patients.

The electroretinogram (ERG) elicited by alternating gratings at constant mean luminance (pattern ERG) is a focal response reflecting the activity of the directly stimulated retinal area. In addition, pattern ERG is related, unlike the flash ERG, to ganglion cell activity. Therefore, this technique may be used to evaluate the integrity of inner retinal layers in the macular region. In this study, the steady-state pattern ERG, in response to alternating gratings (1.7 cycles/deg spatial frequency; 9 degrees field size) temporally modulated at 8 Hz, was recorded in 42 type I (insulin-dependent) diabetic patients with zero to four microaneurysms on fluorescein angiography and a duration of disease less than 11 yr. No patient had concomitant ocular or systemic complications. Mean pattern-ERG amplitude was significantly reduced in patients compared with age-matched control subjects (analysis of variance, F = 25.6, P less than 0.0001). Significant differences were observed between control and diabetic subjects without retinopathy (Scheffé F test, P less than 0.0001), between control and retinopathic subjects (Scheffé F test, P less than 0.0001), and between diabetic patients without retinopathy and those with early retinopathy (Scheffé F test, P less than 0.02). Pattern-ERG amplitude was inversely correlated with duration of diabetes (r = 0.22, P less than 0.05). Our results suggest a macular dysfunction in early diabetes resulting from metabolic and/or vascular injuries in the neurosensory retina.

Adolescent↗
PubMed1990

Toxicity of disodium sebacate.

Investigations of the acute toxicity of disodium sebacate after oral, i.p. and i.v. administration were carried out on 220 Wistar rats (110 males and 110 females) and 204 New Zealand rabbits (102 males and 102 females). No oral acute toxicity was found. On the contrary LD50 +/- s.e. of 5500 +/- 830 mg/kg b.w. and 6000 +/- 850 mg/kg b.w. were found respectively for rats and rabbits after i.p. sebacate administration. When sebacate was given i.v., the median lethal dose +/- s.e. was 560 +/- 86.5 mg/kg b.w. for rats and 1400 +/- 267.2 mg/kg b.w. for rabbits. Similar results were obtained in corresponding groups of animals (in total 220 rats and 204 rabbits) given oral, i.p. and i.v. saline solutions with added glucose in order to obtain the same value of osmolarity and sodium ion concentration. The above results appear indicative of low toxicity of disodium sebacate, and suggest that the toxic effects found could be due to the sodium content of the compound administered. Similarly, subacute and chronic toxicity was investigated in forty rats and forty rabbits (twenty males and twenty females) fed disodium sebacate incorporated into pellets. When compared to the control animals, no significant differences in biological parameters (clinical, chemical and haematological values, growth curves and histological findings for the different organs) were observed in the test groups during the treatment period. In addition, fetal toxicity, teratogenicity and neonatal toxicity were investigated in twenty female rats and twenty female rabbits. Sebacic acid did not show any teratogenic effect and the development of the fetuses was regular.

Animals↗
PubMed1989

Hypothyroidism reduces HDL binding to rat liver cells.

The plasma clearance rate of high density lipoprotein is reduced in the hypothyroid rat. Because the liver is an important site of HDL-cholesterol catabolism, the present study was undertaken to investigate whether thyroid hormone deficiency affects binding of HDL to liver cells. Male Wistar rats were made hypothyroid by feeding propylthiouracil (0.1% w/w). Liver cells were isolated by in situ perfusion of the liver with a buffered collagenase solution. 125I-labelled rat HDL binding to isolated liver cells was carried out at low temperature on ice. For both control and hypothyroid rat liver cells, 125I-HDL binding was significantly inhibited by excess unlabelled rat HDL and also by human HDL3 and human LDL but was unaffected by the addition of 10 mM EDTA. From Scatchard analysis of dose-response studies, hypothyroid cells displayed a lower HDL binding capacity (P less than 0.01) and a higher binding affinity (P less than 0.025) compared to control cells. These results suggest that thyroid hormone affects the expression of the HDL binding site in liver cells which may contribute to the reduced HDL clearance in the hypothyroid animal.

Animals↗
PubMed1989

Spontaneous contractile activity of guinea-pig gall-bladder in vitro.

Some parameters of rhythmic mechanical and electrical events of guinea-pig gall-bladder were investigated. Pressure-volume (P-V) responses, extracellular electrical activity and gall-bladder morphology were recorded. Rhythmic gall-bladder activity consisted of waves of pressure at intraluminal volumes between 0.5 and 1.8 ml. The pressure waveforms developed in a single contraction were usually oscillatory, containing two or more peaks which were more or less separated. The maximum amplitude value of phasic pressure waves was 1.8 +/- 0.6 cmH2O. Bursts of spike potentials appeared at three equidistant electrodes along the longitudinal diameter of the bladder with variable delays indicating absence of propagation of the fast electrical activity. By analysing the morphological changes of gall-bladder silhouette during the P-V curve it was evident that the maximum amplitude and duration of contractile events occurred when the whole muscular wall was stretched. Tetrodotoxin added to the bath solution did not abolish rhythmic activity--indicating its myogenic nature--and shifted the P-V curve to the left of the control, confirming the inhibitory role of the intrinsic nervous plexus of guinea-pig gall-bladder.

Animals↗
PubMed1989

Malignant fibrous histiocytoma of sternum: an unusual cause of pyrexia of undetermined origin.

Malignant fibrous histiocytoma of the bone is a very rare tumour mainly affecting long bones, and the most common presenting symptom is local pain. A case of malignant fibrous histiocytoma presenting with pyrexia of undetermined origin and arising in the sternum, a localization not previously described, is reported. The patient died with septic shock after multi-drug chemotherapy including high dose methotrexate treatment with citrovorum factor rescue.

Adult↗
PubMed1989

Inhibition of basal insulin secretion induces insulin resistance in normal man: evidence for a tonic effect of insulin on carbohydrate metabolism.

Insulin resistance has been demonstrated both in insulin deficiency and insulin excess in man and in animals. This study was carried out in normal man to evaluate the role of insulinopenia in the pathogenesis of insulin resistance. Insulin suppression was obtained by 4 h somatostatin (SRIF) infusion. Insulin receptors on circulating monocytes were evaluated before and after SRIF infusion; an insulin tolerance test (ITT) was performed after SRIF, saline or SRIF and replacing basal insulin secretion. Insulin binding to circulating monocytes did not change after 4 h insulinopenia (2.19 +/- 0.30 vs. 2.35 +/- 0.80%), while insulin sensitivity appeared decreased after SRIF (KITT = 0.97 +/- 0.13) as compared with saline (KITT = 3.30 +/- 0.42), and this effect was prevented by insulin (KITT = 2.46 +/- 0.38). A relationship was detected between KITT and plasma insulin concentration before ITT (r = 0.85, p less than 0.01), suggesting that insulin deficiency is the main cause of the phenomenon observed. The present data suggest that basal insulin concentration plays an essential role in the control of insulin sensitivity. If insulin binding on monocytes mimics the behavior of major insulin target tissues, it is possible that the impaired insulin action after 4 h of insulin deficiency is related to a post binding effect.

Adult↗
PubMed1988

Free fatty acids: a stimulus for mucin hypersecretion in cholesterol gallstone biles.

The concentration of free fatty acids, phosphatidylcholine and lysophosphatidylcholine, and the fatty acid composition as well as the levels of the mucins, analyzed by an improved GLC method, were examined in ten biles from patients with cholesterol gallstones (pathological biles) and in ten control biles. In pathological biles the amounts of free fatty acids and phosphatidylcholine, were significantly higher (8.99 +/- 1.09) vs. 2.75 +/- 0.62 micrograms/mg) and lower (6.62 +/- 0.71 vs. 21.91 +/- 3.86 micrograms/mg), respectively, than in control biles, indicating that a relationship exists between the two lipid fractions. Lysophosphatidylcholine concentrations remained unchanged in the two groups (1.02 +/- 0.55 micrograms/mg in pathological biles vs. 1.32 +/- 0.57 micrograms/mg in control biles). The increased levels of free fatty acids were directly correlated (r = 0.73, P less than 0.05) with biliary hypersecretion of mucus glycoproteins. Acetylglucosamine and acetylgalactosamine were significantly higher in pathological biles than in control biles (1.91 +/- 0.67 vs. 0.60 +/- 0.13 microgram/mg). The nucleating potency of the increased amounts of mucins, coupled with lowered levels of phosphatidylcholine, might play a very important role in stone formation and precipitation.

Adult↗
PubMed1988

Impaired growth hormone response to clonidine in obesity.

Clonidine, an imidazoline derivative, is an antihypertensive agent which reduces sympathetic tone by acting in the central nervous system to stimulate alpha-2 adrenoceptors. There is evidence that dopamine and norepinephrine modulate the secretion of GH. Stimulation of GH release is a well-known effect of clonidine in man. Obesity is characterized by an impairment of GH release in response to various stimuli. The aim of this work is to study GH release in response to alpha-2 adrenoceptors stimulation by clonidine in obesity. 12 volunteer obese subjects were studied. 10 normal weight subjects, sex and age matched, were controls. The GH responsiveness was tested with a single oral dose of clonidine (0.15 mg). Blood was sampled for GH radioimmunoassay at 0', 30', 60', 90', 120', 150', 180'. Serum GH basal levels were not significant different in obese subjects compared to controls. In obese subjects, no significant changes occurred in blood GH concentration after clonidine. In normal weight controls, instead, a significant increase of GH values was reached at 90' (P less than 0.05) and at 120' (P less than 0.05) after clonidine. The impairment of GH release after clonidine in obese subjects might be in a reduced serotonin release or in a failure of the hypothalamic-pituitary system to stimulate plasma GH caused by a diminished GH releasing factor stimulatory effect or by an excessive endorphin or somatostatin secretion in obesity.

Administration, Oral↗
PubMed1988

Effect of fenfluramine on insulin/growth hormone ratio in obese subjects.

Obesity is characterized by increased levels of insulin and by subnormal growth hormone (GH) release. Insulin/GH ratio is significantly higher in obese than in lean individuals. Fenfluramine, an anorectic drug, may have some effects on hypothalamic-pituitary function and on insulin secretion, possibly through a serotonergic stimulation. The aim of this work was to study the effects of fenfluramine on the insulin/GH ratio after arginine in obese subjects. Ten volunteer obese females were studied; 10 volunteer women were the normal weight controls. All subjects were given placebo and fenfluramine (60 mg p.o.) in a randomized order and after 120 min underwent arginine infusion (25 g i.v. for 30 min). Blood samples were taken every 30 min until 270 min for GH and insulin radioimmunoassay. In the obese group the GH response to arginine was significantly lower than in controls. Fenfluramine administration restored the subnormal GH response to arginine in obese subjects. Arginine infusion provoked a greater insulin secretion in obese subjects than in lean individuals. Fenfluramine administration diminished the insulin response to arginine. Fenfluramine did not modify the insulin/GH ratio in controls while it significantly lowered the insulin/GH ratio in obese subjects. Because insulin promotes fat and carbohydrate storage while GH stimulates lipolysis, the combination of high insulin and low GH concentrations may worsen the obese condition. A lower insulin/GH ratio can be useful in the treatment of obesity.

Adult↗
PubMed1988

Glucagon and glucose tolerance in liver cirrhosis.

The present study was undertaken in order to establish the significance of glucagon in glucose intolerance in liver cirrhosis. The plasma glucose response to an oral glucose load (75 g) was determined in 10 control subjects and in 10 cirrhotic patients, after infusions of: glucagon (3 ng.kg-1.min-1) or saline (154 mmol/l); somatostatin (SRIH) (500 micrograms/h); and SRIH plus glucagon (3 ng.kg-1.min-1). Glucagon infusion did not impair glucose tolerance, neither in normal subjects nor in patients with cirrhosis. On the other hand, in both groups glucose tolerance was impaired by SRIH infusion, presumably owing to an absolute insulin deficiency. Both in normal subjects and in cirrhotic patients, SRIH plus glucagon infusion further impaired glucose tolerance, presumably as a result of excess glucagon and concomitant insulin deficiency. In conclusion, our data show that hyperglucagonemia is not an important factor in the development of the glucose intolerance in patients with hepatic cirrhosis.

Adult↗
PubMed1988

Negative correlation between ICA persistence and beta cell restoration after IDDM diagnosis.

We have studied 27 insulin-dependent diabetic patients since diagnosis for a period of six months; at diabetes onset and later on, ICA were found in 17 of them, whereas they were undetectable in 10 patients: age was remarkably homogeneous in the two groups. At diabetes onset, no significant differences were found in insulin requirement between ICA positive and ICA negative patients; however, six months after diagnosis, we observed that insulin requirement to keep metabolic control was significantly higher in ICA positive than in ICA negative subjects (0.515 +/- 0.2 U/Kg versus 0.22 +/- 0.15 U/Kg, p less than 0.001). Only one remission has been detected in ICA positive group (insulin requirement less than 0.25 U/Kg), while four ICA negative patients had complete remission and three had partial remission. ICA positive patients showed fasting C-peptide values higher than ICA negative (0.5 +/- 0.28 ng/ml versus 1.4 +/- 0.5 ng/m.; p less than 0.001, at rest; 1.1 +/- 0.6 ng/ml; versus 2.6 +/- 1.0 ng/ml, 6 minutes after stimulus; p less than 0.05). Our study suggests that presence and persistence of ICA may be considered an early and predictive marker for a worse beta cell function restoration resulting in a higher insulin requirement.

Adolescent↗
PubMed1987

[Lipid lipoperoxidation and atherosclerosis].

The concepts of free radicals, radical reactivity and the mechanism of their production in biological systems are discussed. Emphasis is placed on the mechanisms of lipid damage by initiation, propagation and termination. The free radicals may play a part in the pathogenesis of atherosclerosis.

Arteriosclerosis↗
PubMed1987

Effect of fenfluramine on growth hormone and prolactin secretion in obese subjects.

Obese subjects show a subnormal growth hormone (GH) and prolactin (PRL) release in response to a variety of stimuli. Fenfluramine, an anorexiant drug used in obesity therapy, may have some effects on hypothalamic-pituitary function mediated by serotoninergic stimulation. The present investigation in obese subjects was carried out to study the effects of fenfluramine (60 mg orally) on GH and PRL secretion after intravenous arginine infusion. Ten volunteer obese females were studied and compared with 10 volunteer normal weight controls. In the obese group the GH response to arginine was significantly lower than in control group. Fenfluramine administration restored the subnormal GH response to arginine in obese subjects. The PRL response to arginine in obese women was subnormal. Fenfluramine administration restored the response of PRL to arginine infusion to normal. In conclusion, fenfluramine--under acute circumstances--enhances the hypothalamic-pituitary response to arginine in obese subjects. The decreased GH and PRL output in obese subjects is not due to an absolute hormonal deficiency and this effect of fenfluramine on GH secretion may--due to its lipolysis stimulation--be useful in obesity treatment.

Adult↗
PubMed1986

Appearance of esophageal peristalsis in treated idiopathic achalasia.

The authors studied 22 patients with severe dysphagia, and follow-up studies showed the appearance of some esophageal peristalsis for the first time in three of these patients after Heller myotomy. Comparison of pre- and postoperative clinical, radiological, and manometric data of these three subjects and the data of the other 19 patients showed no statistically significant differences between the two groups of patients either before or after cardiomyotomy except for the unusual appearance of esophageal peristalsis after surgery. According to these results it is not possible to predict which patients will develop peristalsis after cardiomyotomy. The different motor pattern observed after surgery might suggest the existence of a different pathogenesis underlying the esophageal motor disorders in these two groups of patients.

Adolescent↗
PubMed1986

Prediction of lithogenic character of human bile by a quaternary system.

The lithogenic character of human gallbladder bile was investigated by a mathematical model on the basis of a clinical data set. Each bile was described by means of the quaternary system bile salts--phospholipids--free fatty acids--cholesterol. Reporting a set of bile samples on the tetrahedron of concentrations, a clear separation emerged between the control bile, the bile from patients with gallstones, and the bile of subjects with gallbladder dyskinesia. This group was characterized by a largely increased content of free fatty acids.

Adult↗