Contribution of aflatoxin B1 and hepatitis B virus infection in the induction of liver tumors in ducks

The study of two major risk factors in the development of hepatocellular carcinoma, namely persistent hepatitis virus infection and exposure to dietary aflatoxins, has been hampered by lack of an experimental system. To this end we have used a Pekin duck model to examine the effect of congenital duck hepatitis B virus (DHBV) infection and aflatoxin B1 (AFB1) exposure in the induction and development of liver cancer. AFB1 was administered to DHBV infected or noninfected ducks at two doses (0.08 and 0.02 mg/kg) by i.p. injection once a week from the third month posthatch until they were sacrificed (2.3 years later). Two control groups of ducks not treated with AFB1 (one of which was infected with DHBV) were observed for the same period. Each experimental group included 13-16 ducks. Higher mortality was observed in ducks infected with DHBV and treated with AFB1 compared to noninfected ducks treated with AFB1 and other control ducks. In the groups of noninfected ducks treated with high and low doses of AFB1, liver tumors developed in 3 of 10 and 2 of 10 ducks; in infected ducks treated with the high dose 3 of 6 liver tumors were observed and none in the low dose of AFB1. No liver tumors were observed in the two control groups. Ducks infected with DHBV and treated with AFB1 showed more pronounced periportal inflammatory changes, fibrosis, and focal necrosis compared to other groups. All DHBV carrier ducks showed persistent viremia throughout the observation period. An increase of viral DNA titers in livers and sera of AFB1 treated animals compared to infected controls was frequently observed. No DHBV DNA integration into the host genome was observed, although in one hepatocellular carcinoma from an AFB1 treated duck, an accumulation of viral multimer DNA forms was detected. The metabolism of AFB1 in infected and noninfected duck liver was also examined. The study on the role of DHBV infection and AFB1 in the etiopathogenesis of liver tumors may help to clarify some of the basic mechanisms of carcinogenesis.

Effect of treatment on systolic time intervals in systemic arterial hypertension

Twenty six hypertensive patients and 25 control subjects were studied and their systolic time intervals (STI) were measured. It was found that an alteration in STI, signifying left ventricular dysfunction sets in most of the hypertensives earlier than any evidence of left ventricular hypertrophy (LVH) by clinical, radiological or electrocardiographic criteria. The parameters affected are the PEP interval which shows prolongation and PEP/LVET ratio which is increased. After treatment the left ventricular performance was found to improve in those who did not reveal evidence of LVH. Thus STI may be a sensitive indicator of early left ventricular dysfunction in hypertensives and a useful guide to assess improvement after treatment at a stage when other non-invasive methods are not so useful.

Effect of treatment on systolic time intervals in systemic arterial hypertension

Twenty-six hypertensive patients and 25 control subjects were studied, and their systolic time intervals (STI) were measured. It was found that an alteration in STI, signifying left ventricular dysfunction, sets in most of the hypertensives earlier than any evidence of left ventricular hypertrophy (LVH) by clinical, radiological or electrocardiographic criteria. The parameters affected are the PEP interval which shows prolongation and PEP/LVET ratio which is increased. After treatment, the left ventricular performance was found to improve in those who did not reveal evidence of LVH. Thus, STI may be a sensitive indicator of early left ventricular dysfunction in hypertensives and a useful guide to assess improvement after treatment at a stage when other non-invasive methods are not so useful.

Experimental bagassosis: role of infection

The pathological lesions of bagassosis have been reproduced in guinea pigs given bagasse fibers along with low doses of actinomycete spores. In the early stages, interstitial infiltration with lymphocytes and macrophages as seen in humans was noted. Later, small interstitial bagasse granulomas composed of foreign body giant cells, fibroblasts, and lymphocytes developed, some of which had a laminated appearance. Lymph node changes consistent with an immunological reaction were observed. Actinomycetes alone showed occasional areas of pneumonitis and bagasse alone small granulomas consisting of foreign body giant cells and bagasse fibers. Finally, the combined effect of dust and actinomycetes produced interstitial fibrosis composed of thick reticulin fibers and occasional collagen fibers, which persisted to the end of the experiment. Bagasse alone and actinomycetes alone produced only thin reticulin fibers. It has been suggested that bagassosis is due to the synergistic action of bagasse fibers and Micropolyspora faeni and that in the pathogenesis of the syndrome an immunological component may be involved.

Hepatic copper in Indian childhood cirrhosis

Forty-three liver biopsies histologically diagnosed as Indian childhood cirrhosis were studied with the object of investigating accumulation of copper and copper-associated protein in the hepatocytes as demonstrated by the rhodanine and orcein stains respectively. The findings reveal that, in almost all cases, there was an increased accumulation of copper and copper-associated protein, accompanied by the presence of numerous Mallory bodies. It is postulated that the accumulation of copper in the hepatocytes might be the result of a metabolic defect and might be aetiologically related to the liver cell injury and the subsequent development of Indian childhood cirrhosis.

Histological and ultrastructural changes in experimentally produced post-vaccinial lymphadenitis in rabbits

Light and Electron microscopic alterations in lymph nodes after intradermal vaccinia virus inoculation are described. In the early stages the lymph nodes show a diffuse lymphoreticular proliferation associated with the appearance of peculiar large cells called reticulolymphoblasts. This appearance can be mistaken for malignant lymphoma. Later on, these changes are replaced by markedly hypertrophied lymphoid follicles which persist for long periods. These alterations can be mistaken for follicular lymphoma. Evidence is presented that reticulolymphoblasts are derived from transformed lymphocytes.