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Biomedical subjects

O Jurim

Publications and source records attributed to O Jurim.

At least 19 recordsLinked to original sources
PubMed2001

The protective effect of acadesine on lung ischemia-reperfusion injury.

UNLABELLED: The purine precursor acadesine is highly effective in preventing ischemia-reperfusion (I-R) injury of the heart and intestine. The aim of this study was to test the effect of acadesine on I-R--induced lung injury. The lobar artery of the left lower lung lobe in intact-chest, spontaneously breathing cats was occluded for 2 h (Group 1, ischemia) and reperfused for 3 h (Group 2, I-R). Animals were subjected to one of the following three protocols: acadesine administered IV 15 min before ischemia (Group 3), 15 min before reperfusion (Group 4), or 30 min after reperfusion (Group 5). Acadesine was administered at an initial dose of 2.5 mg. kg(-1). min(-1) for 5 min, followed by 0.5 mg. kg(-1). min(-1) until the end of reperfusion. Injury was assessed by histologic examination. The right lower lobe served as control. Compared with the right lower lobe, which showed no abnormal findings in any group (percentage of injured alveoli, 2% +/- 1% to 4% +/- 2%), the left lower lung lobe in the I-R group revealed a disrupted alveolar structure with 63% +/- 9% injured alveoli. Ischemia alone did not produce alterations in alveolar structure. Acadesine significantly reduced the number of injured alveoli when given before ischemia (4% +/- 1%) or reperfusion (6% +/- 2%) but not when administered after reperfusion (62% +/- 8%). In conclusion, acadesine, when administered before ischemia or reperfusion, can blunt I-R-induced lung injury. The mechanism underlying the protection remains to be elucidated. IMPLICATIONS: Acadesine reduces ischemia-reperfusion-induced lung injury in spontaneously breathing cats when administered before ischemia or reperfusion, but not after reperfusion.

Adenosine Triphosphate↗
PubMed2000

Human interleukin-6 facilitates hepatitis B virus infection in vitro and in vivo.

BACKGROUND AND AIM: Research on hepatitis B virus (HBV) infection in vivo has been limited due to the absence of a suitable animal model. We have developed a human-mouse radiation chimera in which normal mice, preconditioned by lethal total body irradiation and radioprotected with SCID mouse bone marrow cells, are permissive for engraftment of human hematopoietic cells and solid tissues. This resulting human-mouse model, which comprises three genetically disparate sources of tissue, is therefore termed Trimera. This study was aimed at assessing the effect of human IL-6 on HBV infection in vivo in Trimera mice. METHODS: Trimera mice were transplanted with human liver tissue fragments or with HepG2-derived cell lines, which had been previously infected ex vivo with HBV in the presence or absence of human interleukin-6 (hIL-6) and in the presence of anti-IL-6-neutralizing antibodies. RESULTS: HBV sequences appeared in the sera of animals in which the liver tissue was incubated with both HBV and hIL-6 prior to transplantation. A similar result was obtained when a human hepatoblastoma cell line (HepG2), expressing the hIL-6 receptor, was infected ex vivo with HBV in the presence of hIL-6 prior to their injection into spleens of Trimera mice. However, when liver fragments were infected ex vivo and simultaneously treated with neutralizing antibodies against hIL-6 or were incubated with HBV prior to transplantation without hIL-6, the rate of mice positive for HBV DNA in their sera was lower. Human mononuclear cells are also permissive for HBV infection in vitro: in the presence of hIL-6 the infection of these cells is enhanced; and this infection is suppressed by the chimeric protein named Hyper-IL-6, generated by the fusion of hIL-6 to the soluble hIL-6 receptor (sIL-6Ralpha, gp80). CONCLUSION: hIL-6 facilitates HBV infection in vitro and in vivo.

Animals↗
PubMed2000

[Laparoscopic adrenalectomy].

Constant advances and increasing experience in laparoscopic surgery renders it applicable for adrenal surgery. The wide exposure required for open adrenal surgery makes this minimally invasive procedure an attractive and advantageous alternative. Between 1996-1999, we performed 35 laparoscopic adrenalectomies in 30 patients 20-72-years old. Indications included: Conn's syndrome--14, pheochromocytoma--11, Cushing's syndrome--6, nonfunctioning adenoma--3, and metastatic sarcoma--1. 5 underwent bilateral laparoscopic adrenalectomy. In 3 (8.5%) the procedures were converted to open operations. Overall morbidity was 13% and there was no mortality. Mean operative time was 188 minutes, but only 130 in our last 10 cases. Mean hospital stay was 4 days and they returned to normal activity an average of 2 weeks later. According to our study and previous reports, laparoscopic adrenalectomy is feasible and safe and it may soon become the procedure of choice for adrenal tumors.

Adenoma↗
PubMed2000

Preclinical evaluation of two human anti-hepatitis B virus (HBV) monoclonal antibodies in the HBV-trimera mouse model and in HBV chronic carrier chimpanzees.

Two human monoclonal antibodies (mAbs) against hepatitis B surface antigen (HBsAg) generated in the Trimera mouse system are described. Both mAbs 17.1.41 and 19.79.5 are of the IgG1 isotype and have high affinity constants for HBsAg binding in the range of 10(-10) mol/L. Monoclonal antibody 17.1.41 recognizes a conformational epitope on the a determinant of HBsAg whereas mAb 19.79.5 recognizes a linear one. The 2 mAbs bind to a panel of hepatitis B virus (HBV) subtypes with distinct patterns. The neutralizing activity of these antibodies was tested in 2 different animal model systems. Administration of each mAb to HBV-Trimera mice, a system that provides a mouse model for human hepatitis B infection, reduced the viral load and the percentage of HBV-DNA-positive mice in a dose-dependent manner. These 2 mAbs were more effective than a polyclonal antibody preparation (Hepatect; Biotest Pharma, Dreieich, Germany) in both inhibition of HBV liver infection and reduction of viral load. A single administration of a mixture of these mAbs into HBV chronic carrier chimpanzees resulted in immediate reduction in HBsAg levels followed by recurrence to initial levels within few days. Thus, these mAbs may be potential candidates for preventive therapy or in combination with other antiviral agents against HBV. Further studies in humans are needed to assess these mAbs in various clinical indications.

Animals↗
PubMed1999

The hepatitis B virus-trimera mouse: a model for human HBV infection and evaluation of anti-HBV therapeutic agents.

Previous studies have demonstrated the feasibility of implantation of human blood cells or tissues in lethally irradiated mice or rats, radioprotected with SCID mouse bone marrow cells: The Trimera system. In the present study, we describe the development of a mouse Trimera model for human hepatitis B virus (HBV) infection. In this model, viremia is induced by transplantation of ex vivo HBV-infected human liver fragments. Engraftment of the human liver fragments, evaluated by hematoxylin-eosin staining and human serum albumin mRNA expression, was observed in 85% of the transplanted animals 1 month postimplantation. Viremia levels were determined in these mice by measuring serum HBV DNA using polymerase chain reaction (PCR), followed by dot-blot hybridization. HBV DNA is first detected 8 days after liver transplantation. Viremia attains a peak between days 18 and 25 when HBV infection is observed in 85% of the transplanted animals. The HBV-Trimera model was used to evaluate the therapeutic effects of human polyclonal anti-HBs antibodies (Hepatect) and of two reverse-transcriptase inhibitors, lamivudine (3TC) and beta-L-5-fluoro-2',3'-dideoxycytidine (beta-L-5FddC). Treatment of HBV-Trimera mice with these drugs effectively reduced both the percentage of infected animals and the viral load in their sera. Treatment cessation resulted in rebound of viral load, indicating HBV replication upon drug withdrawal. These results show that the HBV-Trimera model represents a novel experimental tool for simulating human HBV infection and evaluating potential anti-HBV therapeutic agents.

Animals↗
PubMed1999

Duodenal duplication cyst manifested by duodeno-jejunal intussusception and hyperbilirubinemia.

A rare case of duodenal duplication cyst containing stones in a 17-year-old patient is presented. The cyst, acting as a leading point for duodeno-jejunal intussusception caused proximal small bowel obstruction and hyperbilirubinemia. Preoperative diagnosis was based on abdominal computerized tomography. At operation, the cyst wall was unroofed creating free drainage into the duodenal lumen without damaging the biliary and pancreatic ducts with resolution of symptoms.

Adolescent↗