bThe Vif protein of human immunodeficiency virus type 1 (HIV-1) promotes viral replication by downregulation of the cell-encoded, antiviral APOBEC3 proteins. These proteins exert their suppressive effects through the inhibition of viral reverse transcription as well as the induction of cytidine deamination within nascent viral cDNA. Importantly, these two effects have not been characterized in detail in human CD4؉ T cells, leading to controversies over their possible contributions to viral inhibition in the natural cell targets of HIV-1 replication. Here we use wild-type and Vif-deficient viruses derived from the CD4 ؉ T cells of multiple donors to examine the consequences of APOBEC3 protein function at natural levels of expression. We demonstrate that APOBEC3 proteins impart a profound deficiency to reverse transcription from the initial stages of cDNA synthesis, as well as excessive cytidine deamination (hypermutation) of the DNAs that are synthesized. Experiments using viruses from transfected cells and a novel method for mapping the 3= termini of cDNAs indicate that the inhibition of reverse transcription is not limited to a few specific sites, arguing that APOBEC3 proteins impede enzymatic processivity. Detailed analyses of mutation spectra in viral cDNA strongly imply that one particular APOBEC3 protein, APOBEC3G, provides the bulk of the antiviral phenotype in CD4 ؉ T cells, with the effects of APOBEC3F and APOBEC3D being less significant. Taken together, we conclude that the dual mechanisms of action of APOBEC3 proteins combine to deliver more effective restriction of HIV-1 than either function would by itself.

Summary Truncated Bid (tBid) releases cytochrome c from mitochondria by inducing Bak (and Bax) pore formation in the outer membrane. An important issue is whether a second tBid action, independent of Bak and Bax, is also required to enhance cytochrome c mobility in the intermembrane spaces. To investigate this, we have developed a kinetic analysis enabling changes in the diffusibility of cytochrome c in the intermembrane spaces of isolated mitochondria to be differentiated from changes resulting from Bak activation. Cytochrome c diffusibility in the intermembrane spaces was unaffected by changes in [tBid] over the range 0.5 – 19 pmol / mg mitochondrial protein, when tBid-dependent Bak activation was increased several thousand fold. However, high [tBid] (100 pmol / mg) did increase diffusibility about two-fold. This was attributable to the Permeability Transition. The basal cytochrome c diffusibility in the absence of tBid was determined to be about 0.2 min−1, sufficient to support cytochrome c release with a half time of 3.4 min. It is concluded that tBid has a monofunctional action at low concentrations and, more generally, that the basal cytochrome c diffusibility in the intermembrane spaces is adequate for rapid and complete cytochrome c release irrespective of the mode of outer membrane permeabilisation.

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Introduction Introduced originally to stratify risk for developing decubitus ulcers, the Waterlow scoring system is recorded routinely for surgical admissions. It is a composite score, reflecting patients’ general condition and co-morbidities. The aim of this study was to investigate whether the Waterlow score can be used as an independent surrogate marker to predict severity and adverse outcome in acute pancreatitis. Methods In this retrospective analysis, a consecutive cohort was studied of 250 patients presenting with acute pancreatitis, all of whom had their Waterlow score calculated on admission. Primary outcome measures were length of hospital stay and mortality. Secondary outcome measures included rate of intensive care unit (ICU) admission and development of complications such as peripancreatic free fluid, pancreatic necrosis and pseudocyst formation. Correlation of the Waterlow score with some known markers of disease severity and outcomes was also analysed. Results The Waterlow score correlated strongly with the most commonly used marker of disease severity, the Glasgow score (analysis of variance, p=0.0012). Inpatient mortality, rate of ICU admission and length of hospital stay increased with a higher Waterlow score (Mann–Whitney U test, p=0.0007, p=0.049 and p=0.0002 respectively). There was, however, no significant association between the Waterlow score and the incidence of three known complications of pancreatitis: presence of peripancreatic fluid, pancreatic pseudocyst formation and pancreatic necrosis. Receiver operating characteristic curve analysis demonstrated good predictive power of the Waterlow score for mortality (area under the curve [AUC]: 0.73), ICU admission (AUC: 0.65) and length of stay >7 days (AUC: 0.64). This is comparable with the predictive power of the Glasgow score and C-reactive protein. Conclusions The Waterlow score for patients admitted with acute pancreatitis could provide a useful tool in prospective assessment of disease severity, help clinicians with appropriate resource management and inform patients.

This study demonstrates that reduction of preoperative stay in AC by expediting operations in every eligible patient promises significant surplus revenue. Additional advantages include reducing inpatient bed days and freeing up operating lists that are otherwise taken up by patients for interval cholecystectomy.