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Biomedical subjects

M Zoli

Publications and source records attributed to M Zoli.

At least 181 records · Page 10Linked to original sources
PubMed1988

Polyamines, ornithine decarboxylase, and diamine oxidase in the substantia nigra and striatum of the male rat after hemitransection.

Partial hemitransection at the mesodiencephalic junction in the rat increased striatal and nigral putrescine concentrations on the lesioned side for at least 168 h, with maximal increases between 24 and 48 h. Spermidine and spermine levels declined at 24 h in the striatum, rising above control values at 48 h and further at 168 h. In the substantia nigra, they remained unchanged for the first 48 h and then increased by 168 h. Cadaverine in the striatum also increased at 48 h. On the intact side putrescine increased but to a much lesser extent (at 48 h in the striatum and at 24 and 48 h in the substantia nigra). Ornithine decarboxylase and diamine oxidase activities showed maximal increases at 24 h in the striatum of the lesioned side, whereas in the substantia nigra ornithine decarboxylase attained a very high value as early as 4 h after the operation and diamine oxidase activity peaked at 48 h. The enzyme activities returned toward the basal values at 168 h. On the intact side, ornithine decarboxylase showed a small increase starting at 4 h and diamine oxidase was enhanced at 48 h. These results indicate that the stimulation of biosynthetic and degradative enzymes of polyamine metabolism accompanied by marked and prolonged increases in putrescine may be essential events in the early phases of neuronal response to mechanical injury in the CNS.

Amine Oxidase (Copper-Containing)↗
PubMed1988

Caffeine intake, fasting plasma caffeine and caffeine clearance in patients with liver diseases.

The effects of a variable daily administration of caffeine on fasting levels of caffeine in plasma and in saliva were measured in 24 patients with liver disease and hepatocellular dysfunction of variable degree. For 2 consecutive days the patients received either 250 mg of caffeine (in 2 separate doses of 125 mg each at 8:00 a.m. and at 6:00 p.m.) or a single dose of 125 mg at 6:00 p.m. Caffeine clearance was also measured and the results were correlated with the galactose elimination capacity and with antipyrine clearance. At the beginning of the study, fasting caffeine concentrations were largely variable, without any relation to liver function. A strict negative correlation between fasting caffeine and caffeine clearance was only observed after 2 days of controlled caffeine administration (rs = -0.814). Under these conditions, fasting caffeine also correlated with antipyrine clearance (rs = -0.671, n = 20) and with galactose elimination (rs = -0.565). Our data prove that fasting caffeine concentrations after an evening dose may be used as an index of liver function only in subjects under a strictly controlled dietary caffeine intake. The large availability of caffeine in the diet makes the compound scarcely reliable for a correct measurement of liver function based on a single sample, and correct clearance determination is needed.

Body Weight↗
PubMed1987

Evidence for the existence of ornithine decarboxylase-immunoreactive neurons in the rat brain.

By means of polyclonal antibodies against purified mouse kidney ornithine decarboxylase (ODC) and using the biotin-avidin immunoperoxidase procedure in combination with image analysis the cellular localization and distribution of ODC immunoreactivity (ODC IR) have been demonstrated in the rat brain. ODC IR was located in a large number of neuronal populations. A nuclear ODC IR was always present but in many neurons also a cytoplasmic localization of ODC IR was demonstrated (dendrites, axons and putative terminals). Based on the present findings central neurons may be mapped out not only on the basis of their transmitter contents but also on the basis of their contents of trophic factors.

Animals↗
PubMed1987

Insulin resistance is the main determinant of impaired glucose tolerance in patients with liver cirrhosis.

To clarify the pathogenesis of impaired glucose tolerance in patients with cirrhosis, several factors possibly affecting carbohydrate metabolism were studied in 12 cirrhotic patients with different blood glucose responses to an oral glucose tolerance test. Glucose levels, 120 min after the load, were inversely and significantly related to insulin sensitivity, measured by means of the euglycemic "glucose clamp" technique (r = -0.746). Basal and glucose-induced insulin secretion (insulin and C-peptide levels) only slightly correlated with glucose tolerance, which was not related to functional liver cell mass (galactose elimination), portal-systemic shunting (degree of varices at endoscopy), or maximal glucose-independent insulin secretion (peak C-peptide levels after a glucagon test). Multiple regression analysis identified insulin sensitivity and liver cell mass as the independent variables able to explain most of the variance of 120-min blood glucose (about 84%), and both of them contributed considerably to the regression. While reduced insulin sensitivity is probably the main cause of impaired glucose tolerance, the reduced hepatocellular mass only appears to modulate the degree, and therefore the clinical relevance, of this defect.

Adult↗
PubMed1987

Studies on the cellular localization and distribution of glucocorticoid receptor and estrogen receptor immunoreactivity in the central nervous system of the rat and their relationship to the monoaminergic and peptidergic neurons of the brain.

By means of monoclonal antibodies against the rat liver glucocorticoid receptor (GR) and the human estrogen receptor (ER), in combination with an immunocytochemical analysis, it has been possible to map out GR and ER immunoreactive (IR) neurons in the rat central nervous system and GR IR glial cells in the white matter. The GR IR is located in the cytoplasm and especially in the nucleus while the ER IR is only demonstrated in the nuclei of the neurons. Upon adrenalectomy the GR IR appears to be present exclusively in the cytoplasm, while after castration the ER IR is still exclusively present in the nuclei. Upon corticosterone treatment of the adrenalectomized rat the GR IR is again predominantly found in the nuclei of the neurons. These results indicate that the occupied GR and the unoccupied and occupied ER are located in the nuclei and the unoccupied GR in the cytoplasm. Evidence has been presented that large numbers of monoamine and peptide nerve cell bodies contain GR IR. Furthermore, neuronal GR IR is found in neuronal populations all over the central nervous system, especially in the cerebral cortex, the thalamus and the hypothalamus, indicating a major role of GR in regulating the metabolic and synaptic functions of the brain. The ER IR is instead limited to certain neuronal populations, mainly those of the preoptic area, the bed nucleus of the striae terminalis and the arcuate nucleus, suggesting a specific role in control of LHRH secretion and reproductive behaviour.

Adrenalectomy↗
PubMed1987

Insulin resistance in aged man: relationship between impaired glucose tolerance and decreased insulin activity on branched-chain amino acids.

The effects of glucose-induced hyperinsulinemia on plasma amino acid levels were measured in 50 subjects divided into five age groups. Following an oral glucose load the plasma levels of most amino acids decreased, the decline being more pronounced for the three branched-chain amino acids (valine, isoleucine, and leucine). A progressive insulin resistance was proved on the basis of an age-related impaired glucose tolerance and a normal or increased insulin response. The plasma disappearance of branched-chain amino acids significantly correlated with age (r = -.514). The effects of the prevailing plasma insulin on branched-chain amino acids, measured by the ratio of amino acid changes per total insulin response, progressively declined in older subjects (P = .0005), and strictly correlated with age (r = .652). Insulin resistance in the elderly similarly affects glucose and branched-chain amino acid metabolism, with possible relevant effects on whole-body protein turnover.

Aged↗
PubMed1987

Plasma clearances of branched-chain amino acids in control subjects and in patients with cirrhosis.

In an attempt to clarify the pathogenesis of the decreased branched-chain amino acid (BCAA) plasma concentrations in cirrhosis, the plasma clearances were measured in 7 patients with cirrhosis and in 7 age- and sex-matched control subjects. BCAA were given as prime-continuous infusions. The plasma clearances of valine, isoleucine, and leucine, calculated as infusion rate divided by steady state concentration, were low normal in cirrhotics despite hyperinsulinaemia, but different BCAA had different clearances (P less than 0.01). The endogenous basal appearance rates of BCAA, estimated by the basal concentrations multiplied by the plasma clearances, were lower in cirrhotics (P less than 0.025). The apparent theoretical volumes of distribution of BCAA, assessed by the ratio between the clearance and the concentration decay constant after infusion stop, were on average 67% of the total body weight, and were neither different among the three BCAA, nor between the two groups. The urea nitrogen synthesis rate did not increase significantly, suggesting that most of the infused BCAA nitrogen was taken up in peripheral tissues. The decreased concentration of BCAA in cirrhotics (394 +/- 81 mumol/l (mean +/- SD) in the present series vs 510 +/- 68 in controls; P less than 0.025) is not attributable to changes in plasma clearance. The most likely explanation is decreased afflux of BCAA into plasma.

Adult↗
PubMed1987

Evidence for discrete alterations in central cardiovascular catecholamine and neuropeptide Y immunoreactive neurons in aged male rats and in genetically hypertensive male rats of the Lyon strain.

A computer-assisted morphometrical and microdensitometrical analysis has been performed on cardiovascular noradrenaline (NA), adrenaline (A) and neuropeptide (Y (NPY) neurons in adult and 24-month-old male rats and on hypotensive (LL), normotensive (LN) and hypertensive (LH) male rats of the Lyon strain using the indirect immunoperoxidase procedures. It was found that in NPY/phenylethanolamine-N-methyltransferase (PNMT) costoring neurons of the CI area of the rostral medulla oblongata NPY-like immunoreactivity showed a more marked reduction than the PNMT immunoreactivity. Furthermore, within the parvocellular part of the paraventricular hypothalamic nucleus. NPY immunoreactive nerve terminal profiles were much more affected than the PNMT immunoreactive profiles during aging as revealed by a marked reduction in the number of profiles and by a marked reduction of absorbency values in the microdensitometrical analysis. Thus, in the NPY/PNMT costoring neurons of the A C1 group of the ventrolateral medulla projecting, for example, to the hypothalamus, the peptide transmission line may have a special vulnerability to the aging processes which may contribute to the development of hypertension in old people in view of a vasodepressor role of many central NPY/PNMT neurons. An extensive morphometrical and microdensitometrical analysis of the various catecholamine (CA) cell groups of the medulla oblongata of the LL, LN and LH rats of the Lyon strain was performed. In a comparison between LL and LH rats the A2 cell group of the LH strain showed a trend for an increase in the mean tyrosine hydroxylase (TH) immunoreactive cell body area and the C3 group showed a significant increase in the number of PNMT immunoreactive profiles.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1986

Evaluation of liver volume and liver function following hepatic resection in man.

In a longitudinal study liver volume and liver function were measured in a series of 12 patients undergoing partial liver resection for focal hepatic lesions. Ultrasonography revealed that liver volume, reduced by about 50% by the resection, progressively increased, and 6 months after surgery it returned to nearly normal values. A variable reduction in routine liver function tests was observed, possibly reflecting the influence of the different reserve synthetic capacity of the liver and, in the early postoperative phase, plasma half-life of liver products and blood loss or changes in plasma volume. The galactose elimination capacity was only marginally reduced in the early period (from a pre-surgery value of 2.49 +/- SE 0.21 mmol/min to 2.31 +/- 0.14 after 7 days; p = ns) and reached a nadir at 14 days (1.97 +/- 0.16; p less than 0.001). When expressed per unit of liver volume, the galactose elimination (22 +/- 2 mumol/min per unit before resection) progressively decreased during the regeneration phase from 36 +/- 4 at 14 days to 26 +/- 3 at 6 months (P vs 14-day: less than 0.01). At 6 months both galactose elimination and galactose elimination per unit of liver volume were no longer different from baseline values. Our data show that, following hepatic resection, both liver volume and liver function increase and progressively return to nearly normal values. In agreement with data obtained in animal studies, it appears that the metabolic activity of the remaining parenchyma is increased in the early postoperative phase, and it slows down in the course of regeneration.

Adult↗
PubMed1986

Intravenous uridine treatment antagonizes hypoglycaemia-induced reduction in brain somatostatin-like immunoreactivity.

By means of radioimmunoassay procedures, cholecystokinin-(CCK) and somatostatin-(SRIF) like immunoreactivity have been studied in the dorsal hippocampal formation and in the frontoparietal cortex of the male rat in insulin-induced hypoglycaemia, leading to an isoelectric EEG pattern. It has been demonstrated that severe hypoglycaemia of 40-min-duration produces a disappearance of SRIF but not of CCK-like immunoreactivity in both cortical regions. It was found that an i.v. injection of uridine but not of saline could significantly counteract the disappearance of SRIF-like immunoreactivity induced by severe hypoglycaemia in both cortical areas. Uridine did not by itself change plasma glucose levels. It is suggested that uridine may prevent release and/or increase synthesis of cortical SRIF peptides in severe hypoglycaemia, possibly due to an action on the metabolism (e.g. by enhancing the resynthesis of phosphatidyl inositol) within the tissue of the cerebral cortex and/or on putative pyrimidine binding sites in the brain controlling SRIF synthesis and/or release. It is possible that uridine in this way may improve recovery of neuronal function within SRIF-immunoreactive neurons of the cerebral cortex after severe hypoglycaemia (which also may be true in other states of reduced metabolic support). These findings suggest a possibility to use uridine in the treatment of Alzheimer's disease and Status epilepticus.

Animals↗
PubMed1986

A correlation analysis of the regional distribution of central enkephalin and beta-endorphin immunoreactive terminals and of opiate receptors in adult and old male rats. Evidence for the existence of two main types of communication in the central nervous system: the volume transmission and the wiring transmission.

By means of semiquantitative immunocytochemistry and quantitative receptor autoradiography a correlation analysis has been performed on the pre- and post-synaptic features of enkephalin and beta-endorphin immunoreactive neuron systems of the 3- and 24-month-old male rat. A parallel disappearance of enkephalin- and beta-endorphin-like immunoreactivity and of the density of mu and delta opiate receptors is shown during ageing. Furthermore, the lack of an overall correlation between the amount of pre- and post-synaptic components of the enkephalin and beta-endorphin synapses give evidence for the existence of a volume type of transmission in such systems in the telencephalic, diencephalic and mesencephalic areas analysed.

Age Factors↗
PubMed1986

Sonographic evaluation of liver, spleen, and splanchnic vessels following partial liver resection.

The liver and spleen size and the splanchnic vessel caliber were evaluated by means of real-time ultrasonography in 12 consecutive patients who underwent a partial hepatic resection for benign or malignant lesions. All parameters were evaluated before surgery and 14 days, 28 days, two months, and six months after the partial hepatic resection. The liver size, which was halved after the resection, progressively increased during the follow-up. The splanchnic veins showed, at 14 and 28 days, a significant increase in caliber and a reduced compliance to breathing, which progressively returned to normal levels. The spleen size increased after partial hepatectomy and remained enlarged throughout the study. Ultrasonography was able to detect that partial hepatic resection is followed by a progressive regeneration of the residual parenchyma and by a transient increase in portal pressure, which returns to normal levels when the liver regenerates.

Adult↗
PubMed1985

Effects of neurotoxic and mechanical lesions of the mesostriatal dopamine pathway on striatal polyamine levels in the rat: modulation by chronic ganglioside GM1 treatment.

In male rats, partial hemitransections but not 6-hydroxydopamine (6-OHDA)-induced lesions of the mesostriatal dopamine (DA) pathway produce after 7 days a marked and a modest increase of striatal putrescine and spermidine levels, respectively, on the lesioned side. Following chronic ganglioside GM1 treatment of partially hemitransected rats, an increase of striatal polyamine levels was observed also on the intact side. It is suggested that retrograde cell body changes produced by hemitransection may induce striatal ornithine decarboxylase activity and in this way increase striatal putrescine levels, favoring regenerative mechanisms. The increase of striatal polyamine levels by GM1 treatment on the intact side of both 6-OHDA and mechanically lesioned rats compared with intact unoperated rats may also reflect an increased synthesis of striatal polyamines.

Animals↗
PubMed1985

Morphometrical analysis of the distribution of corticotrophin releasing factor, glucocorticoid receptor and phenylethanolamine-N-methyltransferase immunoreactive structures in the paraventricular hypothalamic nucleus of the rat.

By means of the indirect immunoperoxidase technique the corticotrophin releasing factor (CRF) and glucocorticoid receptor (GR) immunoreactive nerve cell bodies and the phenylethanolamine-N-methyltransferase (PNMT) immunoreactive nerve terminals in the paraventricular hypothalamic nucleus of the rat have been mapped out in adjacent vibratome sections (30 micron thick). By means of morphometrical analysis using a semiautomatic image analyser, it was possible to obtain density maps of CRF, GR and PNMT immunoreactive structures within the paraventricular hypothalamic nucleus. The statistical analysis by the use of correlation coefficients gives evidence that the PNMT immunoreactive nerve terminals innervate the majority of the CRF immunoreactive nerve cell bodies and that GR are located in the majority of the CRF immunoreactive neurons.

Animals↗