Encapsidation of host restriction factor APOBEC3G (A3G) into vif-deficient human immunodeficiency virus type 1 (HIV-1) blocks virus replication at least partly by C-to-U deamination of viral minus-strand DNA, resulting in G-to-A hypermutation. A3G may also inhibit HIV-1 replication by reducing viral DNA synthesis and inducing viral DNA degradation. To gain further insight into the mechanisms of viral inhibition, we examined the metabolism of A3G-exposed viral DNA. We observed that an overall 35-fold decrease in viral infectivity was accompanied by a five-to sevenfold reduction in viral DNA synthesis. Wild-type A3G induced an additional fivefold decrease in the amount of viral DNA that was integrated into the host cell genome and similarly reduced the efficiency with which HIV-1 preintegration complexes (PICs) integrated into a target DNA in vitro. The A3G C-terminal catalytic domain was required for both of these antiviral activities. Southern blotting analysis of PICs showed that A3G reduced the efficiency and specificity of primer tRNA processing and removal, resulting in viral DNA ends that are inefficient substrates for integration and plus-strand DNA transfer. However, the decrease in plus-strand DNA transfer did not account for all of the observed decrease in viral DNA synthesis associated with A3G. These novel observations suggest that HIV-1 cDNA produced in the presence of A3G exhibits defects in primer tRNA processing, plus-strand DNA transfer, and integration.

Extracorporeal membrane oxygenation (ECMO) has been used for >40 years to support lung and heart failure; however, bleeding and thrombosis remain serious complications. The known etiologies of bleeding include heparin effect or overdose, coagulopathy, thrombocytopenia, platelet dysfunction, acquired von Willebrand syndrome, and hyperfibrinolysis. Bleeding sites may include cannula insertion sites, recent surgical incisions, vascular access sites, lung, gastrointestinal tract, mouth, nose, thoracic cavity, abdominal cavity, and brain. Massive bleeding in the brain, the most feared bleeding complication, can be rapidly fatal because it occurs in a rigid closed space, is difficult to drain, and cannot be stopped with direct pressure to the bleeding site. Pulmonary hemorrhage may cause irreversible lung damage. Management should be swift and precise to prevent fatal bleeding. In contrast, etiologies of thrombosis include high fibrinogen and factor VIII levels, heparin resistance, and platelet activation. Achieving the optimal anticoagulation balance to prevent bleeding and thrombosis in ECMO patients is extremely complex. Experts in hemostasis should be a part of an institutional ECMO team and continuously available for immediate management.

The role of nucleocapsid protein (NC) in the early steps of retroviral replication appears largely that of a facilitator for reverse transcription and integration. Using a wide variety of cell-free assay systems, the properties of mature NC proteins (e.g. HIV-1 p7(NC) or MLV p10(NC)) as nucleic acid chaperones have been extensively investigated. The effect of NC on tRNA annealing, reverse transcription initiation, minus-strand-transfer, processivity of reverse transcription, plus-strand-transfer, strand-displacement synthesis, 3' processing of viral DNA by integrase, and integrase-mediated strand-transfer has been determined by a large number of laboratories. Interestingly, these reactions can all be accomplished to varying degrees in the absence of NC; some are facilitated by both viral and non-viral proteins and peptides that may or may not be involved in vivo. What is one to conclude from the observation that NC is not strictly required for these necessary reactions to occur? NC likely enhances the efficiency of each of these steps, thereby vastly improving the productivity of infection. In other words, one of the major roles of NC is to enhance the effectiveness of early infection, thereby increasing the probability of productive replication and ultimately of retrovirus survival.

Forty-four percent of pediatric patients who failed conventional cardiopulmonary resuscitation from in-hospital cardiopulmonary arrest and who were reported to the National Registry of CardioPulmonary Resuscitation database as treated with extracorporeal cardiopulmonary resuscitation survived to hospital discharge. The majority of survivors with recorded neurologic outcomes were favorable. Patients with cardiac illness category were more likely to survive to hospital discharge after treatment with extracorporeal cardiopulmonary resuscitation. Extracorporeal cardiopulmonary resuscitation should be considered for select pediatric patients refractory to conventional in-hospital resuscitation measures.

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The nucleocapsid (NC) protein from HIV-1 contains two zinc-fingers, both of which are necessary for virus replication. This is the first in-depth study that presents the effects of nucleocapsid zinc-finger substitutions on the kinetics of reverse transcription and integration. Over a 72-h time-course of infection, the quantities of viral DNA (vDNA) observed with viruses containing either the nucleocapsid His23Cys or His44Cys mutations were significantly lower than those observed in infections with virus containing wild-type NC. In addition, the kinetics of vDNA formation and loss were significantly different from wild-type. The kinetic profiles observed indicated reduced vDNA stability, as well as defects in reverse transcription and integration. Overall, the defect in integration was much more pronounced than the reverse transcription defects. This suggests that the principal reason for the replication defectiveness of these mutant viruses is impairment of integration, and thus demonstrates the critical importance of NC in HIV-1 infection.

Twenty patients who had undergone anterior cruciate ligament reconstructive surgery were placed randomly and independently in an Electrical Stimulation Group (n = 10) or Voluntary Exercise Group (n = 10) to compare the effectiveness of these two muscle-strengthening protocols. Patients in both groups used simultaneous contraction of quadriceps femoris and hamstring muscles during a training regimen that consisted of either voluntary exercise or electrical stimulation trials five days a week for a three-week period within the first six postoperative weeks. After patients completed the training regimen, bilateral maximal isometric measurements of gravity-corrected knee extension and flexion torque were obtained for both groups and percentages were calculated. Results showed that patients in the Electrical Stimulation Group finished the three-week training regimen with higher percentages of both extension and flexion torque when compared with patients in the Voluntary Exercise Group (extension: t = 4.35, p less than .05; flexion; t = 6.64, p less than .05). These results indicate that patients in an electrical stimulation regimen can achieve higher individual thigh musculature strength gains than patients in a voluntary exercise regimen when simultaneous contraction of thigh muscles is prescribed during an early phase of postoperative rehabilitation.