Human T cells transduced by a retroviral vector to express Herpesvirus saimiri proteins TIP and STPC.

Herpesvirus saimiri is a virus capable of inducing oncogenic transformation of T lymphocytes of New World primates and immortalizing human T cells in vitro. T lymphocytes immortalized by H. saimiri demonstrate functional biological responses to their antigens. Therefore, H. saimiri-induced transformation of T cells emerges as a very powerful tool of T-cell biology. Although the mechanism of this transformation remains to be understood, it is thought that H. saimiri proteins Tip and StpC play important roles. To facilitate functional studies of Tip and StpC, we retrovirally transduced human MOLT4, Jurkat and JCaM1 T-cell lines to express these H. saimiri proteins, using a three-plasmid system allowing for rapid and efficient production of high-titer retroviral stocks. Several cell lines expressing Tip and/or StpC in a stable fashion were obtained and characterized.

Biochemical and structural correlates in unloaded and reloaded cat myocardium.

Cardiocytes of unloaded myocardium rapidly lose structural and functional integrity through a combined loss of myofibrils and contractile activity; both changes are reversible with load restoration. The present study correlates the biochemical composition of unloaded and reloaded myocardium with these alterations in structure and function. Cardiac muscle was unloaded by transecting the chordae tendineae of a cat right ventricular papillary muscle and was reloaded by suturing these same chordae tendineae to the ventricular wall at the base of the valve; an adjacent intact muscle served as the control. Muscles unloaded for 1 to 14 days were assayed for DNA, protein, total creatine and hydroxyproline content. The ratios of wet weight/DNA and creatine/DNA decreased by 30 and 22% respectively, in parallel with a 38% reduction in cardiocyte cross-sectional area. Protein/unit wet weight was decreased by 50% after 14 days of unloading, so that both protein/DNA and protein/creatine were markedly reduced. Reloading of the muscle restored cardiocyte size, protein per unit wet weight and protein/DNA to normal. Parallel reductions in both contractile filaments and contractile proteins after unloading and parallel increases in each following load restoration were demonstrated by morphometric analysis of electron micrographs and analysis of actin and myosin by gel electrophoresis. In summary, the myocardium undergoes marked, parallel changes in structure, function and biochemical composition in response to the removal and restoration of load.

Monitoring metabolic control in diabetic outpatients with glycosylated hemoglobin.

The usefulness of HbA, as a monitor of metabolic control was studied in 15 diabetic outpatients during periods of stable, deteriorating, and improving control. Mean fasting concentrations of HbA, and plasma glucose during a 3-month period of stable control were 12.6% +/- 0.8% and 120 +/- 8 mg/dL, respectively. One week after discontinuation of oral hypoglycemic therapy, blood glucose had risen to 172 +/- 23 mg/dL and HbA, to 14.1% +/- 0.7% (P less than 0.025). Reinstitution of therapy resulted in a significant fall of blood glucose within 2 weeks. A significant decline in HbA1 (from 15.3% +/- 0.8% to 14.1% +/- 0.9%, P less than 0.025) occurred 2 weeks later. The data show that the rate of formation of HbA1 is considerably faster than its rate of disappearance. Thus, HbA1 is likely to reflect disproportionally recent episodes of poor control. We conclude that HbA1 is useful to monitor diabetic outpatients during periods of stable and rapidly deteriorating control but is not suited to detect rapid metabolic improvements.