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Biomedical subjects

S Raimondo

Publications and source records attributed to S Raimondo.

At least 19 recordsLinked to original sources
PubMed2007

Comparison of fresh and predegenerated muscle-vein-combined guides for the repair of rat median nerve.

Over the last 10 years, we have investigated a particular type of bioengineered nerve guide, the muscle-vein-combined tube, which is made by filling a vein with skeletal muscle. In our previous studies we have always used fresh skeletal muscle to fill vein conduits. In the present study we compared the use of fresh and predegenerated (freeze-thawed) skeletal muscle for muscle-vein-combined nerve guides. In this study, a 10-mm-long rat median nerve defect was repaired using either type of nerve guide. The samples were analyzed 5 and 30 days after surgery by light and electron microscopy. In addition, reverse transcription polymerase chain reaction (RT-PCR) was carried out to investigate the expression of mRNAs coding for glial markers, as well as glial growth factor (NRG1) and its receptors (erbB2 and erbB3). Results showed differences between the two types of nerve guides at postoperative day 5; however, no difference was detected at day 30 suggesting that both types of tissue-engineered conduit are effective for repairing peripheral nerve defects in this experimental model.

Animals↗
PubMed2006

Lack of topographic specificity in nerve fiber regeneration of rat forelimb mixed nerves.

Multiple nerve repair by means of a Y-shaped nerve guide represents a good model for studying the specificity of peripheral nerve fiber regeneration. Here we have used it for investigating the specificity of axonal regeneration in mixed nerves of the rat forelimb model. The left median and ulnar nerves, in adult female rats, were transected and repaired with a 14-mm Y-shaped conduit. The proximal end of the Y-shaped conduit was sutured to the proximal stump of either the median nerve or the ulnar nerve. Ten months after surgery, rats were tested for functional recovery of each median and ulnar nerve. Quantitative morphology of regenerated myelinated nerve fibers was then carried out by the two-dimensional disector technique. Results showed that partial recovery of both median and ulnar nerve motor function was regained in all experimental groups. Performance in the grasping test was significantly lower when the ulnar nerve was used as the proximal stump. Ulnar test assessment showed no significant difference between the two Y-shaped repair groups. The number of regenerated nerve fibers was significantly higher in the median nerve irrespectively of the donor nerve, maintaining the same proportion of myelinated fibers between the two nerves (about 60% median and 40% ulnar). On the other hand, nerve fiber size and myelin thickness were significantly larger in both distal nerves when the median nerve was used as the proximal donor nerve stump. G-ratio and myelin thickness/axon diameter ratio returned to normal values in all experimental groups. These results demonstrate that combined Y-shaped-tubulization repair of median and ulnar nerves permits the functional recovery of both nerves, independently from the proximal donor nerve employed, and that tissue, and not topographic, specificity guides nerve fiber regeneration in major forelimb mixed nerves of rats.

Animals↗
PubMed2003

Schwann-cell proliferation in muscle-vein combined conduits for bridging rat sciatic nerve defects.

Among the various grafting procedures that have been studied as alternatives to traditional fresh nerve autografts for the repair of severed peripheral nerves, muscle-vein-combined graft conduits have recently been devised and successfully employed. In the present study, the early presence, origin, and proliferation activity of Schwann cells (SCs) along this particular type of biological graft conduit have been investigated, using antibodies directed against glial fibrillar acid protein (GFAP), a protein that is specifically expressed in glial cells, and proliferating cell nuclear antigen (PCNA), a protein that is expressed by cells during DNA synthesis. Results showed that the muscle-vein-combined graft was progressively invaded by a number of GFAP-immunopositive SCs, many of which were also found to be immunopositive for PCNA, thus demonstrating that their proliferation continues to occur inside the graft. Among the molecules that could be involved in the stimulation of Schwann-cell proliferation is neuregulin-1 (NRG-1) that mediates its effects by binding to the ErbB receptor tyrosine kinase family. In the present study, the authors report on the RT-PCR analysis for NRG-1 and ErbB3 mRNAs, showing an overall increase in the content of these transcripts inside the muscle-vein-combined graft. These results suggest that the muscle-vein-combined graft conduit constitutes an environment favorable to potentiate Schwann-cell proliferation during the early regeneration phases.

Animals↗
PubMed1986

Somatostatin and cimetidine in the control of acute upper gastrointestinal bleeding. A controlled multicenter study.

Acute upper gastrointestinal bleeding remains a difficult emergency problem, and, despite recent pharmacological advances, the choice and results of medical treatment are the subject of debate. To determine the effectiveness of two potent inhibitors of gastric acid secretion, somatostatin and cimetidine, in the control of upper gastrointestinal bleeding of non-variceal origin, we initiated a multicentric, randomized, prospective therapeutic trial in 56 patients presenting with acute hemorrhage due to gastric and duodenal ulcers and erosions defined by uniform and precise criteria. The two drugs were administered i.v. for 48 hours at a dose of 250 mcg/h (somatostatin) and 1,600 mg/24 h (cimetidine). Vital signs, laboratory values, and gastric aspirate were checked frequently in accordance with a strict schedule; the number of blood transfusions was also noted. Endoscopy for the assessment of bleeding before admission to the trial and the end of treatment was performed in every patient. Bleeding stopped in 28 of the 30 (93.3%) patients treated with somatostatin, and in 16 of the 26 (61.5%) of those receiving cimetidine (p less than 0.01). The blood requirement of the patients treated with somatostatin and cimetidine was, on average, 1.10 +/- 1.16 and 2.46 +/- 4.03 units per patient, respectively (p less than 0.05). Somatostatin was also significantly superior - in the patients in whom the treatments were successful - with respect to the time taken to achieve this result. In conclusion, our results, together with those already published, point to a definite therapeutic effectiveness of somatostatin in upper gastrointestinal bleeding as here defined, and would appear to justify a more extensive clinical use under controlled conditions.

Acute Disease↗
PubMed1983

Experimental chronic epilepsy in rats: a screening method for antiepileptic drugs.

Rats were rendered epileptic by subpial injection of an FeCl3 solution. Epileptiform discharges, recorded by chronically implanted extradural electrodes, were evident within 48 h of surgery and persisted for more than 6 months. It is demonstrated that this model is useful for studying new antiepileptic agents since a series of clinically effective drugs (diazepam, clonazepam, Na phenobarbital, primidone, carbamezepine, ethosuximide, diphenylhydantoin, Na valproate, GABOB) show an activity which is does-dependent and within a range satisfactorily related to human dosages.

Animals↗
PubMed1983

[Somatostatin].

Explore the source record for details and available documents.

Adenoma, Islet Cell↗
PubMed1983

Effect of somatostatin on the pituitary-thyroid axis.

We studied the effect of Somatostatin on the pituitary-thyroid axis of 37 volunteer subjects. 17 were euthyroid, 12 hypothyroid, 7 hyperthyroid and one had a TSH secreting pituitary adenoma. We measured by radioimmunoassay plasma iodothyronines T4, T3, rT3, FT4 and FT3, as well as TSH in basal conditions and after TRH stimulation. Somatostatin (as an initial bolus of 250 micrograms i.v. followed by an infusion of 500 micrograms/h) was given in short-term infusion (3 h) or long-term infusion (12 h). The results obtained showed that during short-term infusion Somatostatin: does not influence TSH in normal subjects; reduces significantly basal TSH in hypothyroid patients; reduces significantly the TSH response to TRH both in normal and in hypothyroid subjects as well as in the case with a TSH secreting pituitary adenoma. During long-term infusion Somatostatin: does not change TSH levels in normal or hyperthyroid subjects; does not change the values of T4, FT4, T3, FT3 and rT3 in normal subjects; does not change the values of T4 and FT4 in hyperthyroid subjects but reduces significantly the values of T3 and FT3 and produces a marked rise in rT3 in the same ones. In conclusion, the inhibiting effect of exogenous Somatostatin is evident whenever TSH levels are high for pathological conditions or for drug stimulation. The findings of T3 and FT3 reduction with a marked rise in rT3 in hyperthyroid subjects during the long infusion indicate an extrathyroidal effect of Somatostatin on the peripheral metabolism of iodothyronines.

Adolescent↗
PubMed1982

Influence of age upon the cerebral metabolic changes induced by acute hypoxia on the synaptosomes from dog brain.

The synaptosomal fraction obtained from the motor area of the cerebral cortex of normocapnic, normoxic or hypoxic "young adult," "mature" and "senescent" beagle dogs is incubated and analyzed for : ATP, ADP, AMP, creatine phosphate, pyruvate and lactate. The data are compared with those obtained from the whole controlateral cortical motor area, by the surface freezing technique. After hypoxic hypoxia /15 min; PaO2 = 17-19 mm Hg), the metabolite contents and ratios are differently affected by ageing when the evaluations are performed in the incubated synaptosomal preparation or in the controlateral whole cerebral tissue. In fact, ageing does not affect so much the cerebral changes that occur in the overall energetic state during the hypoxic assault in vivo, but rather those that the synaptosomes remember the tend to reverse during the subsequent incubation in vitro. The protective action of several drugs on the synaptosomal phosphorylation state is tested. Phenobarbital shows a quite broad, age-independent spectrum of action. (-)Eburnamonine and dihydroergocristine exhibits a more limited, age-dependent effectiveness, but are devoid of anesthetic action. Papaverine proves unable to affect the tested biochemical parameters.

Adenine Nucleotides↗
PubMed1981

Metabolic changes induced by acute hypoxia on the synaptosomes from dog brain.

Synaptosomal preparations from the motor area of the cerebral cortex of normocapnic, normoxic or hypoxic untreated beagle dogs and phenobarbital-, papaverine-, and (-) eburnamonine-treated dogs were incubated for 10 min at 24 degrees C and analyzed for ATP, ADP, AMP creatine phosphate, pyruvate, and lactate. The data were compared with those obtained from the whole controlateral cortical motor area, by the surface-freezing technique. Both during normoxia and after hypoxic hypoxia (15 min, at PaO2 equal to 17-19 mm Hg) the metabolite contents and ratios were very different in the incubated synaptosomal preparations and in the whole cerebral tissues. As concerns the drug treatment, papaverine was always inactive, while (1) eburnamonine increased the synaptosomal phosphorylation state in hypoxic dogs, being ineffective on the glycolytic metabolites evaluated. Phenobarbital increased the synaptosomal phosphorylation state both in normoxic and in hypoxic animals, and was effective also on the glycolytic metabolites studied.

Adenine Nucleotides↗
PubMed1981

Cerebral enzymatic activities during chronic hyperammonemia and treatment with S-adenosyl-L-methionine, adenosine and methionine in the rat.

The effect of the chronic intramuscular administration of some agents related to the S-adenosyl-L-methionine system on the hyperammonemia syndrome was evaluated. This experimental syndrome was induced in the rat by intraperitoneal administration of high doses of ammonium acetate (33, 100 and 300 mg/kg/day, 6 days a week for 80 days) followed by the assay of the activities of some cerebral enzymes involved in energy transduction. The enzymatic activities studied in the homogenate and in the mitochondrial fractions of brain tissue were: lactate dehydrogenase, citrate synthase, malate dehydrogenase, total NADH-cytochrome c reductase and cytochrome oxidase. All three doses of ammonium acetate induced significant modifications in the cerebral enzymatic activities. These doses reduced the activity of the total NADH-cytochrome c reductase both in the homogenate and in the mitochondrial fraction. On the other hand the activity of malate dehydrogenase was reduced limited to the two lower doses in the homogenate only. The simultaneous daily treatment (i.m.) with equimolar doses of substances involved in the S-adenosyl-L-methionine system (adenosine, methionine and S-adenosyl-L-methionine) did not cause any significant modification of the cerebral enzymatic activities associated with the administration of ammonium acetate at the three dose levels, thus confirming our previous results.

Adenosine↗
PubMed1981

UDP-glucose effect on phrenic diaphragm preparation of the rat.

The effects of uridine-5'-diphosphoglucose (UDPG) on the contractile response of the phrenic nerve-diaphragm preparation and on carbohydrate metabolism in the diaphragmatic muscle were studied in the rat. In the preparations obtained form rats, the contracturant action of UDPG, previously observed in guinea-pig preparations, was thus confirmed. This action was compared with those of uridine, UMP and UDP. Uridine alone was ineffective, while the higher concentration of both UMP and UDP induced a contracture comparable with that shown for the lower concentration of UDPG. This indicates that the action of UDPG is partially related at least to one phosphate-group into its molecular structure. In addition, several substrates and intermediates related to carbohydrate metabolism (glycogen, glucose, glucose-6-phosphate) were measured in the diaphragm, their concentrations proving unaffected by UDPG perfusion.

Animals↗
PubMed1980

Drug interference on some biochemical parameters of rat cerebral cortex during post-ischemic recovery.

Glycolytic substrates and metabolites (glycogen, glucose, glucose-6-phosphate, pyruvate, lactate), tricarboxylic acid cycle intermediates (citrate, alpha-ketoglutarate, succinate, fumarate, malate), related amino acids (glutamate, glutamine, alanine, gamma-aminobutyrate) and energy mediators (ATP, ADP, AMP, creatine phosphate) were evaluated in the cerebral cortex of rats after 5 min of complete compression ischemia as well as after 3, 15 or 30 min of recirculation following 5 min ischemia. The post-ischemic recovery was studied in control animals or in animals treated (30 min before ischemia and during discovery) by intravenous perfusion of vincamine, theophylline, dihydroergocristine and alanine. Interrelated changes of intermediates of the carbohydrate and the amino acid metabolism have been observed. It is concluded that alanine perfusion induced a partial detour of the lactacid anaerobic process towards the succinate-related alactacid cycle, leading to an increase in the cortical gamma-aminobutyrate content. Vincamine and dihydroergocristine acted in the opposite direction.

Alanine↗
PubMed1979

In vitro action of uridine diphosphate glucose (UDPG) on phrenic diaphragm preparations.

The action of uridine-5'-diphosphoglucose (UDPG) on the contractile response of the phrenic diaphragm preparation from guinea pig was investigated. UDPG activity was assayed on the preparation at rest or during the exercise; in this case indirect electrical stimulation of phrenic diaphragm preparation or direct stimulation of denervated or curarized muscle were employed. Krebs' solutions adequately modified with regard to glucose concentration were used. The effect of UDPG on the neuromuscular junction was also investigated by recording miniature end plate potentials. An effect of the drug on neuromuscular transmission and on glucose metabolism could be demonstrated.

Action Potentials↗
PubMedDate not supplied

A seroepidemiological study of toxoplasma gondii infection in children of northern Greece.

The aims of this study were to determine the incidence of toxoplasmosis in children ofthe northern Greece region through the evaluation of serologic examination. Sera of 486 children, aged between 6 months and 15 years, suffering from different clinical entities, were tested for anti-Toxoplasma gondii specific IgG antibodies, using an ELISA (enzyme linked immunosorbent assay) technique. In this survey, a high percentage (11.1 percent) of the hospitalized children reacted positively to this method. Males and females had equal prevalence, 11 percent and 11.2 percent, respectively. Seropositivity rate was higher in children aged between 6 and 10 years old. In conclusion, our results indicate toxoplasma infection is an important public health problem affecting children and adolescents in northern Greece. We believe that the study described here could be considered for inclusion in existing national screening programs for hospitalized children.

Journal Article↗