A rat model of monitoring liver allograft rejection

Rat models are often used to study liver allograft rejection. We have established a model for rat liver allograft rejection, monitored by fine needle aspiration biopsy (FNAB), in the strain combination PVG-to-BN with a mean survival time of 37 ± 20 days. In this model, we observed acute rejection with an intense peak of lymphoid blasts and lymphocyte-dominated inflammation in the FNAB [9.1 ± 3.0 corrected increment units (CIU)], and an eventual increase in macrophages (up to 4.2 ± 4.4 CIU), together with fibrosis and parenchymal necrosis in the graft. Markers of immune activation, such as an increase in IL-2-receptor (from 1 % ± 2 % to 21 % ± 13 %) and class II (from 20 % ± 9 % to 43 % ± 13 %) expressing lymphoid cells and induction of ICAM-1 in the graft, were consistent with the overall cellular response. The FNAB correlated well with parallel graft histology. In this rat model, the atraumatic monitoring makes a close follow-up possible without having to sacrifice the experimental animals. This saves work, animals, and costs in the study of liver rejection. Received: 2 July 1996 Accepted: 28 October 1996     

Comparison of Plasma Protein Binding of Basic Drugs in Black and White Individuals

Interethnic difference in drug disposition is an important contributing factor to interindividual variation in drug response. Since interethnic differences in the protein binding of drugs may contribute to variation in drug disposition between ethnic groups, we conducted a study in 10 black Americans (A) and mean (plus minusSE) age 26 plus minus 6 years and weight 80 plus minus 9 kg matched against 10 white Americans (C) with a mean age of 28 plus minus 6 years and weight 81 plus minus 9 kg, all within 10% of ideal body weight. Serum alpha-1-acid glycoprotein (AGP) and albumin concentrations were measured using the auramine-O and bromcresol green methods, respectively. Verapamil, propranolol, lidocaine, disopyramide and diazepam binding in plasma were measured with the equilibrium-dialysis method, involving the determination of free and unbound drug concentrations. The unbound fraction of diazepam (A = 1.1 plus minus 0.1%; C = 1.1 plus minus 0.1%), verapamil (A = 9.5 plus minus 0.8%; C = 9.8 plus minus 0.4%), propranolol (A = 14.2 plus minus 1.0%; C = 12.6 plus minus 0.7%), lidocaine (A = 28.5 plus minus 2.1%; C = 25.7 plus minus 1.1%) and diphenhydramine (A = 42.9 plus minus 10.2; C = 30.4 plus minus 7.01%) showed no significant ethnic differences (unpaired t-test). Disopyramide measured at 7 different concentrations (1.0--20.0 &mgr;g/ml) was similar in both groups, as were the plasma concentrations of AGP (A = 100 plus minus 20 mg 100 ml; C = 120 plus minus 20 mg 100 ml) and albumin (A = 4.3 plus minus 0.1 g 100 ml; C = 4.5 plus minus 0.1 g 100 ml). It is therefore concluded that there are no interethnic differences in the protein binding of basic drugs between black Americans and white Americans and that it is not a major contributing factor to any possible interethnic variation in the disposition of responsiveness of these drugs.     

Laparoscopic appendectomy--considerations in about 1000 cases

Laparoscopic appendectomy (LA) is a well spread method today, but not as largely accepted as cholecystectomy, the cure of gastro-esophageal reflux and some other procedures (relatively small in number) for which the laparoscopic approach is the golden standard. Otherwise it is improbable that LA will gain such a status, at least in the near future. On the other hand it is obvious that LA offers important advantages for some special situations: the right iliac area syndrome, obesity, professional sportsmen, abnormal localization of the appendix, as well for the cases when localized and especially diffuse peritonitis is associated. Our paper analyses the experience of General Surgery Department at the "St.John" Emergency Hospital Bucharest on laparoscopic appendectomy. The retrospective study includes 996 cases that were treated laparoscopic between 1996-2004. Of these 745 cases were catarrhal, 166 cases were phlegmonous and 76 gangrenous appendicitis. In 93 cases localized or diffuse peritonitis was associated. There were recorded also 3 cases of each of the following: chronic appendicitis, appendicular mass and mucocele. The number of conversions was 28 (2.81%). There were also 10 reinterventions (1.004%), 7 because of intraperitoneal abscess and we also recorded one death.     

Use of octreotide to treat prolonged sulfonylurea-induced hypoglycemia in a patient with chronic renal failure

A diabetic patient with chronic renal failure who developed recurrent and prolonged episodes of hypoglycemia associated with use of sulfonylurea agent is presented here. This patient was hospitalized with neuroglycopenic symptoms of hypoglycemia that persisted in spite of large doses of parenteral glucose replacement. On administration of somatostatin analogue octreotide, hypoglycemia resolved and, blood glucose levels were maintained even after cessation of parenteral glucose. The patient received 2 subcutaneous doses of octreotide 12 hours apart, and made a complete recovery. Our experience suggests that use of octerotide to treat refractory or prolonged sulfonylurea-included hypoglycemia in renal failure patients is safe and effective; large prospective studies would be needed to validate these findings.     

The inhibitory effects of herbal components on CYP2C9 and CYP3A4 catalytic activities in human liver microsomes

Herbal medicines are widely consumed by patients in different clinical settings in the United States and all over the world. In this study, 7 herbal components ginsenosides Rb1, Rb2, Rc, and Rd (from ginseng quercetin) ginkgolides A and B (from ginkgo biloba) were investigated for their inhibitory effects on hepatic CYP2C9 and CYP3A4 catalytic activities in human liver microsomes. Tolbutamide 4-methylhydroxylation and testosterone 6beta-hydroxylation were used as index reactions of CYP2C9 or CYP3A4 catalytic activities, respectively. The metabolites of both reactions were measured by high-performance liquid chromatography and used as indicators of whether enzymes were inhibited or unaffected by these agents. Herbal components were studied at various concentrations (0.1, 1, 10, 100, 200 micromol/L). The herbal compounds investigated were capable of inhibiting CYP2C9 and CYP3A4 catalytic activities, but the potencies differed. Quercetin showed marked inhibitory effects on both tolbutamide 4-methylhydroxylation and testosterone 6beta-hydroxylation with IC(50) values of 35 and 38 micromol/L, respectively. Ginsenoside Rd also had significant inhibitory potency on both CYP2C9- and CYP3A4-mediated index reactions with IC(50) values of 105 and 62 micromol/L, respectively. Ginsenosides Rb1, Rb2, and Rc had limited inhibitory activities on both enzyme reaction systems, whereas the effects of ginkgolides A and B appeared negligible. It is concluded that the components of ginseng and ginkgo biloba screened are capable of inhibiting CYP2C9- and CYP3A4-mediated metabolic reactions. Our findings suggest that quercetin and ginsenoside Rd have the potential to interact with conventional medicines that are metabolized by CYP2C9 and CYP3A4 in vivo.     

Clinical experience with stentless pericardial aortic monopatch for aortic valve replacement

A stentless pericardial aortic monopatch was used in 60 consecutive patients undergoing aortic valve replacement. The monopatch is constructed of a sheet of glutaraldehyde-treated bovine pericardium, tailored and shaped to fit the aortic anulus, and is sutured in place without a stent or sewing ring. The valve area is effectively preserved by this method. Results indicate that this technique is simple, inexpensive, and applicable to all cases of aortic valve disease. It does not require anticoagulation and may allow for annular growth when used in children. This technique is particularly suitable for patients with infective endocarditis because the amount of foreign material is minimized.     

Tolerance liability of diazepam is dependent on the dose used for protracted treatment

BackgroundBehavioral effects of benzodiazepines following repeated exposure vary according to the intrinsic efficacy of the benzodiazepine studied, treatment schedule and the behavioral parameters evaluated.MethodsWe applied the behavioral paradigms of spontaneous locomotor activity, elevated plus maze and grip strength to investigate the sedative, anxiolytic and myorelaxant effect of acute challenge with 2 mg/kg diazepam administered after 14 days of protracted treatment with 0.5, 2 or 10 mg/kg of diazepam. In addition, we studied the effects of everyday handling and intraperito-neal (ip) administration on animal behavior.ResultsTolerance to the sedative effect of 2 mg/kg diazepam ensued after 14 days of protracted treatment with 2 and 10 mg/kg of diazepam. In contrast, treatment with the lowest dose (0.5 mg/kg) of diazepam resulted in potentiation of the sedative effect of acute challenge with 2 mg/kg diazepam thus confounding the detection of the anxiolytic effect of diazepam. A sensitization-like response to the anxiolytic action of 2 mg/kg diazepam was seen after protracted treatment with the intermediate dose (2 mg/kg); however, anxiolytic effect was absent after protracted administration of the highest dose. Partial tolerance to the muscle relaxant effect of 2 mg/kg diazepam ensued after protracted treatment with diazepam regardless of the dose. Daily handling or ip administration did not alter the behavioral response to acute challenge with 2 mg/kg diazepam in all the three behavioral paradigms studied.ConclusionThe presented results showed that behavioral effects of acute challenge with diazepam were differently affected by the dose administered during protracted treatment.     

Impaired endothelial antithrombotic activity following short-term interruption of continuous subcutaneous insulin infusion in type 1 diabetic patients

Review of literature has shown an increased rate of thrombotic complications in diabetic patients with frequent episodes of hyperketonemia. However, the mechanisms by which ketosis promotes vascular disease in diabetic patients are unclear. It was the aim of this study to investigate early changes in haemostatic parameters and oxidative stress markers during the hyperketonemic status which follows the interruption of continuous subcutaneous insulin infusion (CSII) in type I diabetic patients. Eight CSII-treated type I diabetic patients underwent a 4-hour pump arrest. Blood glucose, insulin and 3-hydroxybutirate were measured to verify the metabolic response. A vein-occlusive (VO) test was performed for the determination of tPA and PAI-1 activities and their antigen levels before and after the CSII arrest. Coagulation factor VII and VIII were evaluated by one-stage PT and PTT method, respectively. TF, vWF, tPA and PAI-1 antigens were determined by ELISA, whereas tPA and PAI-1 activities using chromogenic methods. Plasma malondialdehyde (MDA) and protein carbonyl groups (PCG) levels were determined by HPLC and spectrophotometry, respectively. After the insulin deprivation phase, post-VO tPA antigen level significantly decreased (P = 0.0391), whereas TF and post-VO PAI-1 activity and antigen levels significantly increased (P = 0.0156 and P = 0.0234, respectively). Plasma MDA and PCG levels were 1.88-fold and 1.74-fold higher than baseline values, respectively. In conclusion, the impairment of the fibrinolytic potential and the increases in TF, MDA and PCG levels may enhance the risk of both arterial and venous thrombosis during ketosis. Thus, early detection of hyperketonemia in DM patients could contribute to the prevention of life-threatening vascular events.