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Biomedical subjects

A Marni

Publications and source records attributed to A Marni.

At least 19 recordsLinked to original sources
PubMed1998

CD4+ and CD8+ T cell subset distribution in the blood of small-bowel-grafted rats: modification during graft-versus-host disease.

We studied the modifications of blood T cell distribution following small-bowel allografting in rats under different experimental conditions. Group 1: ACI (RT1a) rats were used as small-bowel donors for ACI x Wistar (RT1y) F1 hybrid rats (WAF1) in which graft-versus-host disease (GVHD) developed. Group 2: WAF1 rats were used as small-bowel donors to ACI rats which developed rejection. Group 3: WAF1 rats received small bowel from ACI rats hyperimmunized for 10 days (by grafting them with WAF1 skin) and GVHD developed. Group 4: Wistar rats received small bowel from ACI rats hyperimmunized for 10 days (by Wistar skin) and bidirectional GVHD and rejection were assured. A second set of the same groups which were continuously administered with cyclosporine (15 mg/kg per day s.c. for 15 consecutive days) was also studied. Recipient peripheral blood lymphocytes, obtained at 7 and 15 days following small-bowel transplantation, were stained with monoclonal antibodies anti-rat CD4 and CD8 and then analyzed in an automated flow cytometer. A significant major reduction of CD4+/CD8+ T cell ratios was shown in rats that developed simultaneous GVHD and rejection with respect to ungrafted rats.

Animals↗
PubMed1996

End-to-side anastomosis in heterotopic rat organ transplantation.

A partial modification of the standard end-to-side anastomosis usually performed in heterotopic vascularized organ transplantation in the rat is described. Use of the method completely abolished the approximately 20% severe post-declamping bleeding due to gaps in those blind areas, the stitching of which are at risk using previously described methods. The authors thus recommend the method for performing heart, kidney, pancreas and small bowel transplantations in the rat.

Anastomosis, Surgical↗
PubMed1996

The anti-ischemic drugs defibrotide and oligotide analogously inhibit leukocyte-endothelial cell adhesion in vitro.

Defibrotide (a polydeoxyribonucleotide) and oligotide (an oligodeoxyribonucleotide) obtained from mammalian single-stranded DNA, have been demonstrated to have anti-ischemic activity in some experimental models of ischemia/reperfusion of kidney in rats. We hypothesized that their anti-ischemic activity could be related to an inhibition of leukocyte-endothelial cell adhesion and also the consequent generation of oxygen free radicals by leukocytes. We studied the in vitro adhesion of neutrophils to human umbilical vein endothelial cells under basal conditions and following neutrophil or endothelial cell activation (using 10(-7) fMLP and 500 U/ml TNF-alpha, respectively). Defibrotide and oligotide significantly inhibited neutrophil adhesion to endothelial cells (after only 1 min of drug treatment). When the anti-LFA-1 70H12 F(ab)2 monoclonal antibody was used, the drugs exerted only slight additional inhibition of the adhesion of fMLP-activated neutrophils to endothelium. These results, confirmed in NIH/3T3-ICAM-1-transfected cells, demonstrate that defibrotide and oligotide interfere with leukocyte adhesion to endothelial cells by an LFA-1-dependent mechanism.

3T3 Cells↗
PubMed1991

Protection of rat heart from damage due to ischemia-reperfusion during procurement and grafting by defibrotide.

We studied the efficacy of defibrotide, a prostacyclin-stimulating agent, in preventing ischemia reperfusion injury in Wistar rat heart by using three experimental models: (1) hearts from donors were perfused with the drug (32 mg/kg/hr) during 15, 30, 45, and 60 min of cold ischemia following 5, 10, and 15 min of warm ischemia; (2) hearts from donors treated with the drug were cold-stored for 12 or 24 hr; and (3) procured hearts perfused with the drug were isografted, after 30 or 60 min of warm ischemia, in recipient rats treated daily with defibrotide. Hearts perfused with saline and/or vehicle of the drug were used as controls. At the end of established ischemia times, and after 30 min, and 2, 4, 7 and 14 days from transplantation, hearts were rapidly cooled in liquid nitrogen. ATP, ADP, AMP, cAMP contents, and NAD+/NADH ratios were evaluated in prepared tissue extracts. Cardiac ATP and ADP levels and NAD+/NADH ratios were significantly higher in defibrotide-treated organs than in controls. Isografted defibrotide-treated hearts were also significantly preserved, with respect to controls, from the loss of ATP levels until rejection occurred. Our results demonstrate the protective activity of the drug against the myocardial metabolic damage due to ischemia-reperfusion.

Adenosine Diphosphate↗
PubMed1991

Are increased ATP blood levels responsible for PGI2 release from endothelium?

Defibrotide, a polydeoxyribonucleotide with profibrinolytic and antithrombotic properties obtained from mammalian lungs was shown capable of favoring the release of prostacyclin from endothelial cells. We previously evidenced that the use of defibrotide i.p. (32 mg/kg for 30 min) or orally (50 mg/kg for 1 h) induced a significant increase in 2,3-diphosphoglycerate (2,3-DPG) content of blood cells in rats. We tested the in-vivo capacity of defibrotide to modify over 90 min the blood content of ATP, cAMP and 2,3-DPG. Male Wistar rats were anaesthetized with pentobarbital (20 mg/kg) i.p.; the left carotid artery was cannulated with a polyethylene tube, from which 0.4 ml of blood was drawn at 0, 5, 10, 15, 20, 30, 40, 50, 60 and 90 min. At 0 min, defibrotide was administered i.p. or i.v. (through the femoral vein) at the dose of 1 ml containing 80 mg of drug or orally at the dose of 1 ml containing 160 mg of drug. The control rats employed received either the vehicle of the drug or physiologic saline. Our results demonstrated a significant drug-related increase with time (maximal levels were revealed about 20 min after i.v., i.p., or oral defibrotide treatment) of blood ATP content and a significant decrease in cAMP content as compared with the controls. Our data confirm the relation between increased drug-induced prostacyclin production and that of ATP of in blood.

2,3-Diphosphoglycerate↗
PubMed1991

Prostacyclin release from endothelial cells, induced by defibrotide treatment, favours the function of grafted rat hearts and kidneys.

Defibrotide, a single-stranded DNA fraction obtained from mammalian lungs and able to increase prostacyclin production by endothelial cells, has been shown to be efficient in protecting rat organs (heart, kidney and liver) from ischaemic damage. We studied the efficacy of the drug in preserving the function of rat heart and kidney submitted to isotransplantation. Defibrotide was administered to donor Wistar rats at the dose of 32 mg/kg in 1.5 ml of saline. Heart and kidney were isolated and cold-preserved in buffered phosphate medium and continuously infused with defibrotide (32 mg/h) through the innominate or renal artery. Recipient Wistar rats were treated with defibrotide before and after transplantation at the dose of 32 mg/kg/day. Controls were treated with the vehicle of the drug. The function of isografted organs was evaluated at 12 and 24 h and at 2, 4 and 7 days from grafting. Heart function was evaluated by studying creatinine phosphokinase (CPK) and lactic dehydrogenase (LDH) activities of myocardial tissue. Renal function was evaluated by studying serum creatinine and urea levels of kidney-grafted rats. CPK and LDH activities were found to be significantly higher in defibrotide-treated rats than in controls. Creatinine and urea levels remained significantly lower in defibrotide-treated rats than in the controls. The results of the present work indicate that defibrotide treatment is useful to maintain the functionality of grafted hearts and kidneys.

Animals↗
PubMed1990

Prevention of impaired liver metabolism due to ischemia in rats. Efficacy of defibrotide administration.

The effect of defibrotide treatment in protecting liver metabolism from ischemic damage was studied. The drug was administered to male Wistar rats as a bolus (30 mg/kg body weight) at the beginning of 60 min ischemia and then continuously during 60 min of postischemic reperfusion at a dose of 30 mg/kg body weight. This dose was previously identified as useful to protect against myocardial ischemia induced in the cat. ATP and ADP intrahepatic levels were significantly higher in drug-treated rats than in untreated animals. The liver cytoplasmic NAD+/NADH ratio in defibrotide-treated rats was no different from that observed in sham-operated rats. The mitochondrial NAD+/NADH ratio in the liver was also improved by defibrotide treatment. Our data suggest that defibrotide may exert protective activity on hepatocytes useful for inducing a rapid restoration of their metabolism. Such a restoration is possibly related to improvement of microcirculation through an increase in prostaglandin I2 production or oxygen delivery due to drug administration.

Adenine Nucleotides↗