Hepatic B-cell non-Hodgkin's lymphoma of MALT type in the liver explant of a patient with chronic hepatitis C infection.

B-cell non-Hodgkin's lymphoma (B-NHL) is a well-documented complication of hepatitis C virus (HCV) infection. Marginal zone (mucosa-associated lymphoid tissue; MALT) lymphomas constitute a less common type of B-NHL. In this article, we report a case of liver MALT in a cirrhotic patient, incidentally discovered after liver transplantation (LT). We discuss pertinent diagnostic and management strategies in this clinical setting.     

The pony as an animal model for vascular implants

This study evaluated the pony as a potentially suitable model for vascular implant research. Healthy, conditioned ponies were randomly assigned to one of three groups: group I, carotid artery autografts (n = 6); group II, e-PTFE carotid interpositional grafts (n = 5); and group III, e-PTFE carotid interpositional grafts plus aspirin (10 mg/kg) and dipyridamole (3.5 mg/kg) drug administration. It was found that autografts remained patent longest (mean = 396.2 days; grafts were still patent at time of writing) followed by group III grafts (157.5 days), with group II grafts remaining patent for the shortest duration (61.1 days), (p less than 0.01). Patency was determined using two-dimensional real-time ultrasonography with Doppler velocimetry and/or arteriography. It was demonstrated that the pony's response to antithrombotic drugs was consistent and comparable to that in other animal models, both with respect to platelet function and affect on patency rate. The combination of the ease of surgical manipulation, drug administration, and platelet function testing, the comparable size of the pony and its heart and blood vessels to that of an adult human, the long life span of ponies, and the patency results of this study have demonstrated that the pony is a valuable animal model for vascular research.     

Effects of transforming growth factor alpha and interleukin-1 on DNA synthesis, collagen synthesis, procollagen mRNA levels, and prostaglandin E2 production in cultured fetal rat calvaria

Transforming growth factor alpha (TGF-alpha) and interleukin-1 (IL-1) have been shown to affect bone metabolism in vitro by prostaglandin-dependent and PG-independent mechanisms. We assessed the effects of the combination of these two agents on [3H]thymidine (TdR) incorporation into DNA, DNA content, [3H]proline incorporation into collagenase-digestible (CDP), noncollagen protein (NCP), and PGE2 production in 21 day fetal rat calvaria cultured for 24-96 h. We also determined whether TGF-alpha plus IL-1 altered procollagen mRNA levels at 96 h. TGF-alpha, 1-30 ng/ml, produced a 41-59% increase in TdR incorporation into DNA, but the effect was partially blocked by human recombinant IL-1. At 96 h TGF-alpha alone or in combination with IL-1 significantly increased the DNA content of calvaria. At 96 h, TGF-alpha inhibited CDP labeling and the addition of IL-1 further enhanced this inhibitory effect. The enhanced inhibitory effect of TGF-alpha plus IL-1 on collagen synthesis was associated with a synergistic increase in prostaglandin accumulation in the medium. Addition of indomethacin blocked PGE2 accumulation and partially reversed the inhibitory effect of TGF-alpha alone or in combination with IL-1 on collagen synthesis. TGF-alpha decreased procollagen mRNA levels by 55%, but the combination of TGF-alpha plus IL-1 decreased procollagen mRNA levels by 82%. Our results show that TGF-alpha and IL-1, which are both produced by certain tumors as well as activated macrophages, appear to act synergistically to increase prostaglandin synthesis and inhibit collagen synthesis in vitro. Thus these agents may have a regulatory role on bone formation in vivo.