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Assembly of type C retroviruses such as Moloney murine leukemia virus (M-MuLV) ordinarily occurs at the plasma membranes of infected cells and absolutely requires the particle core precursor protein, Pr65m. Previously we have shown that Pr659E' is membrane associated and that at least a portion of intracellular Pr658" protein appears to be routed to the plasma membrane by a vesicular transport pathway. Here we show that intracellular particle formation can occur in M-MuLV-infected cells. M-MuLV immature particles were observed by electron microscopy budding into and within rough endoplasmic reticulum, Golgi, and vacuolar compartments. Biochemical fractionation studies indicated that intracellular Pr65"" was present in nonionic detergent-resistant complexes of greater than 150S. Additionally, viral RNA and polymerase functions appeared to be associated with intracellular particles, as were Gag-Il-galactosidase fusion proteins which have the capacity to be incorporated into virions. Immature intracellular particles in postnuclear lysates could be proteolytically processed in vitro to mature forms, while extracellular immature M-MuLV particles remained immature as long as 10 h during incubations. The occurrence of M-MuLV-derived intracellular particles demonstrates that Pr6Sgg can associate with intracellular membranes and indicates that if a plasma membrane Pr65O receptor exists, it also can be found in other membrane compartments. These results support the hypothesis that intracellular particles may serve as a virus reservior during in vivo infections. To assemble an infectious retrovirus particle, several components must colocalize and assemble in an ordered manner. The major viral structural protein (Gag) is central to the assembly process (40). The Gag protein is cotranslationally myristylated at its amino terminus (17), and acylation of the matrix domain is required for membrane association and assembly (30). There appear to be 5,000 to 10,000 precursor Gag molecules in each virus particle (40), which oligomerize to form the viral core. In the case of Moloney murine leukemia virus (M-MuLV) and other retroviruses, expression of the Gag protein alone produces noninfectious virus particles (15, 21, 37). The M-MuLV Gag protein is synthe

Background Renal transplant candidates are at high risk of fatal and nonfatal cardiac events. Methods This study evaluated five clinical risk factors -age at least 50 years, insulin-requiring diabetes mellitus, angina, congestive heart failure and an abnormal electrocardiogram (ECG) (eXcluding left ventricular hypertrophy) -that had been Used in the first tier of a two-tiered prospectively applied risk stratification algorithm.ReSUlts Using multiple logistic regression analysis, age at least 50 years, abnormal ECG, and diabetes mellitus were independently predictive of cardiac death. Of the two remaining clinical risk factors, the presence of angina had independent predictive value for nonfatal cardiac events (myocardial infarction, coronary angioplasty, bypass surgery, and unstable angina). The independent predictive value of congestive heart failure approached statistical significance.Conclusion Clinical risk-factor analysis is helpful in identifying renal transplant candidates at high risk for fatal or nonfatal cardiac events. J Cardiovasc Risk 6:251-255 © 1999 lippincott Williams &Wilkins.