Characterization of GBV-C infection in HIV-1 infected patients

BACKGROUND: GB virus C, a positive-stranded RNA virus, is classified in the family Flaviviridae. It is currently believed that persistent infection occurs in 25-50% of infected individuals, however, it still remains an "orphan" virus in search of a role in human pathology. Molecular epidemiological studies have demonstrated that GBV-C infection is present in about 1-1.4% of the healthy population in developed countries, that it shares routes of transmission with HIV and HCV and that the prevalence of GBV-C in these populations is higher than in blood donors. On the basis of the sequence variation among the isolates, GBV-C is classified into at least four major genotypes. Preliminary evidence has suggested that GBV-C is a lymphotropic virus that replicates mainly in the spleen and bone marrow. Recently, several reports have investigated the possible beneficial effect of GBV-C co-infection on HIV disease progression to AIDS, reduced mortality in HIV infected individuals and lower HIV viral loads, not leading to a definitive conclusion yet. AIM: To investigate the role of GBV virus C co-infection in two different subsets of HIV-infected patients, and to evaluate the prevalence of GBV-C genotypes in Northern Italy. METHODS: A total of 86 HIV positive patients were examined for GBV-C viremia (years after HIV sera conversion: 12 +/- 5). Control population (Group A): 46 patients (mean age 42 years) with <200CD4/ml during the observation period. Longterm non progressor population (Group B): 40 patients, (mean age 40 years) with >500 CD4/ml for at least 8 years and never treated with HAART. After extraction of viral RNA from plasma samples, amplification of a highly conserved region of 5'UTR was performed by nested RT-PCR. All positive samples were genotyped by sequencing, alignment with published sequences and phylogenetic analysis. CD4 cell count, HIV plasma levels were also evaluated. RESULTS: 9 out of 46 (19.56%) in Group A and 15 out of 40 (37.5%) in Group B had detectable GBV-C viremia (p=0.064, OR 2.47, percent confidence interval 0.94 to 6.51). No statistical difference was observed when disease stage was evaluated between the two groups. In Group B, after regression analysis for CD4 cell count decrease over the period observed, no significant difference was detected between GBV-C positive and negative patients. No significant difference was observed in Group B in HIV viremia and CD4 cell count at time of GBV-C detection between GBV-C infected patients and GBV-C negative patients. All Italian patients were genotype 2, the only African patient carried GBV-C genotype 1. CONCLUSIONS: Although previous results suggest that GBV-C virus may be a favorable marker for long term non progression of HIV disease, whether it plays a direct anti-HIV role or just takes advantage of non progessors' higher CD4 cell count to replicate more efficiently, still remains to be answered. Follow up of untreated patients and further evaluation of virological interactions, between the viruses and the host immune system, will be helpful to shed some light on these observations, offering new prognostic and eventually therapeutical tools for the management of HIV patients.     

The effect of copper/zinc replacement on the folding free energy of wild type and Cys3Ala/Cys26Ala azurin

The effect of copper/zinc metal ion replacement on the folding free energy of wild type (w.t.) and disulfide bridge depleted (C3A/C26A) azurin has been investigated by differential scanning calorimetry (DSC) and fluorescence techniques. The denaturation experiments have shown that, in both cases, the thermal transitions of the zinc derivative of azurins can be depicted in terms of the classical Lumry–Eyring model, NUF, thus resembling the unfolding path of the two copper proteins. The thermally induced transition of Zn azurin, monitored by fluorescence occurs at lower temperature than the DSC scans indicating that a local conformational rearrangement of the Trp microenvironment, takes place before protein denaturation. For Zn C3A/C26A azurin, the two techniques reveal the same transition temperature. Comparison of the thermodynamic data shows that the presence of Zn in the active site stabilises the three-dimensional structure of azurin only when the disulfide bridge is present. Compared to the copper form of the protein, the unfolding temperature of Zn azurin has increased by 4 °C, while the unfolding free energy, ΔG, is 31 kJ/mol higher. Both enthalpic and entropic factors contribute to the observed ΔG increase. However, the copper/zinc replacement has no effect on the unfolding free energy of C3A/C26A azurin. Taking Cu azurin w.t. as the reference state, for both Cu and Zn C3A/C26A azurin the unfolding free energy is decreased by about 28 kJ/mol, indicating that metal substitution is not able to compensate the destabilising effect induced by the disulfide bridge depletion. It is noteworthy that the thermal denaturation of the Zn derivative, which thermodynamically is the most stable form of azurin, is also characterized by the highest value of the activation energy, E_a, as derived from the kinetic stability analysis.     

Are Movements Necessary for the Sense of Body Ownership? Evidence from the Rubber Hand Illusion in Pure Hemiplegic Patients

A question still debated within cognitive neuroscience is whether signals present during actions significantly contribute to the emergence of human’s body ownership. In the present study, we aimed at answer this question by means of a neuropsychological approach. We administered the classical rubber hand illusion paradigm to a group of healthy participants and to a group of neurological patients affected by a complete left upper limb hemiplegia, but without any propriceptive/tactile deficits. The illusion strength was measured both subjectively (i.e., by a self-report questionnaire) and behaviorally (i.e., the location of one’s own hand is shifted towards the rubber hand). We aimed at examining whether, and to which extent, an enduring absence of movements related signals affects body ownership. Our results showed that patients displayed, respect to healthy participants, stronger illusory effects when the left (affected) hand was stimulated and no effects when the right (unaffected) hand was stimulated. In other words, hemiplegics had a weaker/more flexible sense of body ownership for the affected hand, but an enhanced/more rigid one for the healthy hand. Possible interpretations of such asymmetrical distribution of body ownership, as well as limits of our results, are discussed. Broadly speaking, our findings suggest that the alteration of the normal flow of signals present during movements impacts on human’s body ownership. This in turn, means that movements have a role per se in developing and maintaining a coherent body ownership.     

Hospital Admission of Cancer Patients: Avoidable Practice or Necessary Care?

Background

Cancer patients are frequently admitted to hospital due to acute conditions or refractory symptoms. This occurs through the emergency departments and requires medical oncologists to take an active role. The use of acute-care hospital increases in the last months of life.

Patients and methods

We aimed to describe the admissions to a medical oncology inpatient service within a 16-month period with respect to patients and tumor characteristics, and the outcome of the hospital stay.

Results

672 admissions of 454 patients were analysed. The majority of admissions were urgent (74.1%), and were due to uncontrolled symptoms (79.6%). Among the chief complaints, dyspnoea occurred in 15.7%, pain in 15.2%, and neurological symptoms in 14.5%. The majority of the hospitalizations resulted in discharge to home (60.6%); in 26.5% the patient died and in 11.0% was transferred to a hospice. Admissions due to symptoms correlated with a longer hospital stay and a higher incidence of in-hospital death.

Conclusion

We suggest that hospital use is not necessarily a sign of inappropriately aggressive care: inpatient care is probably an unavoidable step in the cancer trajectory. Optimization of inpatient supportive procedures should be a specific task of modern medical oncology.     

Association of dystrobrevin and regulatory subunit of protein kinase A: a new role for dystrobrevin as a scaffold for signaling proteins

The dystrophin-related and -associated protein dystrobrevin is a component of the dystrophin-associated protein complex, which directly links the cytoskeleton to the extracellular matrix. It is now thought that this complex also serves as a dynamic scaffold for signaling proteins, and dystrobrevin may play a role in this context. Since dystrobrevin involvement in signaling pathways seems to be dependent on its interaction with other proteins, we sought new insights and performed a two-hybrid screen of a mouse brain cDNA library using beta-dystrobrevin, the isoform expressed in non-muscle tissues, as bait. Among the positive clones characterized after the screen, one encodes the regulatory subunit RIalpha of the cAMP-dependent protein kinase A (PKA). We confirmed the interaction by in vitro and in vivo association assays, and mapped the binding site of beta-dystrobrevin on RIalpha to the amino-terminal region encompassing the dimerization/docking domain of PKA regulatory subunit. We also found that the domain of interaction for RIalpha is contained in the amino-terminal region of beta-dystrobrevin. We obtained evidence that beta-dystrobrevin also interacts directly with RIIbeta, and that not only beta-dystrobrevin but also alpha-dystrobrevin interacts with PKA regulatory subunits. We show that both alpha and beta-dystrobrevin are specific phosphorylation substrates for PKA and that protein phosphatase 2A (PP2A) is associated with dystrobrevins. Our results suggest a new role for dystrobrevin as a scaffold protein that may play a role in different cellular processes involving PKA signaling.     

Liver glyconeogenesis: a pathway to cope with postprandial amino acid excess in high-protein fed rats?

This paper provides molecular evidence for a liver glyconeogenic pathway, that is, a concomitant activation of hepatic gluconeogenesis and glycogenesis, which could participate in the mechanisms that cope with amino acid excess in high-protein (HP) fed rats. This evidence is based on the concomitant upregulation of phosphoenolpyruvate carboxykinase (PEPCK) gene expression, downregulation of glucose 6-phosphatase catalytic subunit (G6PC1) gene expression, an absence of glucose release from isolated hepatocytes and restored hepatic glycogen stores in the fed state in HP fed rats. These effects are mainly due to the ability of high physiological concentrations of portal blood amino acids to counteract glucagon-induced liver G6PC1 but not PEPCK gene expression. These results agree with the idea that the metabolic pathway involved in glycogen synthesis is dependent upon the pattern of nutrient availability. This nonoxidative glyconeogenic disposal pathway of gluconeogenic substrates copes with amino excess and participates in adjusting both amino acid and glucose homeostasis. In addition, the pattern of PEPCK and G6PC1 gene expression provides evidence that neither the kidney nor the small intestine participated in gluconeogenic glucose production under our experimental conditions. Moreover, the main glucose-6-phosphatase (G6Pase) isoform expressed in the small intestine is the ubiquitous isoform of G6Pase (G6PC3) rather than the G6PC1 isoform expressed in gluconeogenic organs.