Regression of a Large Congenital Hepatic Arteriovenous Malformation

Congenital hepatic arteriovenous malformations are rarely seen in association with persistent neonatal pulmonary hypertension. We report the case of a full-term female newborn who presented with heart failure and respiratory distress soon after birth. Echocardiographic investigation revealed severe persistent pulmonary hypertension and patent ductus arteriosus. Here we report spontaneous regression in size of both the feeder vessel and the vascular bed of the congenital hepatic arteriovenous malformation. We postulate that our conservative use of oral heart failure therapy, in the form of diuretic agents and captopril, decreased the congestion and diameter of the affected vessels.     

The hepatitis C virus (HCV)-Trimera mouse: a model for evaluation of agents against HCV.

The lack of small-animal models that are suitable for evaluation of agents used to treat infection with hepatitis C virus (HCV) severely hinders the assessment of potential new therapies for the disease. This study created such a model, termed the "HCV-Trimera" model. The HCV-Trimera model was developed by using lethally irradiated mice, reconstituted with SCID mouse bone marrow cells, in which human liver fragments infected ex vivo with HCV had been transplanted. Viremia (positive-strand HCV RNA levels) in HCV-Trimera mice peaked at approximately day 18 after liver transplantation, and an infection rate of 85% was reached. Viral replication in liver grafts was evidenced by the presence of specific negative-strand HCV RNA. The usefulness of this model for evaluation of anti-HCV agents was demonstrated by the ability of a small molecule (an HCV internal ribosomal entry site inhibitor) and an anti-HCV human monoclonal antibody (HCV AB(XTL)68) to reduce virus loads in HCV-Trimera mice in a dose-dependent manner.     

Osteonecrosis

Formerly referred to as avascular necrosis, the term osteonecrosis is now preferred. Simply defined, osteonecrosis means ‘dead bone’. The ‘avascular’ state of the necrotic bone is the result of a loss of circulation from numerous potential causes together with multiple risk factors. The resultant state is a sequelae of repair processes leading finally to gross deformation of the bony structural architecture and joint incongruity. Among the commonest sites are the femoral head, talus, lunate, knee and humeral head. In addition to normal radiography, bone scan and MRI have provided early diagnosis of subtle changes in the osteo-histology. Intervention depends upon the phase of disease progression; in the form of a series of preservation and/or salvage procedures.     

Association of right heart thrombosis,endomyocardial fibrosis,and pulmonary artery aneurysm in Behçet's disease

A 29-year-old man with a 5-year history of Beh?et's disease was admitted for fever, dyspnae, chest pain, and hemoptysis. A diagnosis of right ventricle and atrial thrombosis associated with a pulmonary artery aneurysm was made. The patient was treated with anticoagulants and prednisone. Since hemoptysis persisted, surgical excision of the intracardiac thrombosis was performed and histological findings were consistent with organizing thrombus and endomyocardial fibrosis. Transesophageal echocardiography 6 months later showed recurrence of the right ventricle thrombosis. A course of 6-monthly boluses of intravenous cyclophosphamide was begun. Currently, at 2 years of follow-up, the patient is asymptomatic.     

Cardiac growth patterns in response to chronic hypoxia in a neonatal rat model mimicking cyanotic heart disease

OBJECTIVE:

Myocardial growth during fetal life is accomplished by the proliferation of myocytes. Shortly after birth, normal myocytes largely lose their capability to replicate. The present study aims to assess the effect of persistent postnatal hypoxia on myocardial growth patterns in an animal model mimicking cyanotic heart disease.

METHODS:

Sprague-Dawley rats were placed in a normobaric hypoxic environment at birth and oxygen levels were maintained at 10% (group H). Controls (group C) remained in room air. The animals were sacrificed and the hearts were harvested at one, four and eight weeks.

RESULTS:

Significant polycythemia developed in the hypoxic rats. There was a significant increase in indexed right ventricle (RV) and left ventricle (LV) masses compared with controls. Myocardial DNA concentrations were significantly increased in both ventricles of the hypoxic rats. For the RV, the increase in DNA content for group H was 135%, 132% and 112% that of group C values at one, four and eight weeks, respectively. RV and LV myocardial protein:DNA ratios were lower in the one-week- and four-week-old hypoxic rats, and significantly higher in the hypoxic eight-week-old rats. Polyploidy, hydroxyproline concentrations and dry:wet weight ratios were not significantly different in the LV and RV between both group H and group C animals.

CONCLUSION:

Cardiac mass increases in response to chronic hypoxia were greater in the RV than the LV. This increase was mainly due to myocardial proliferation in the first four weeks of life. Although the three groups of hypoxic rats had significant elevations in DNA concentration compared with controls, there was a shift from proliferation to hypertrophy after week 4 of life. The age of the myocyte appears to be the most important factor in triggering proliferation in this hypoxic animal model.