VIRUSES & PARASITES: surface mapping of Env glycoprotein from HIV and role of hexose-6-phosphate mutarotase from Trypanosoma brucei in oxidative stress.

Protein studies on HIV Most efforts in HIV vaccine development have been based on the use of structural proteins Env, and most recently of regulatory protein Tat. The rational for this approach is based on these facts: i) the presence of anti-Tat antibodies seems to protect infected individuals from progressing to AIDS ii) biologically active Tat is immunomodulatory. In addition Tat is released by infected cells and binds to the surface of both HIV-1 infected and surrounding uninfected cells instructing these to become more prone to infection. There are evidences for a specific interaction between Tat and Env, which enhances virus attachment and entry into cells. The molecular complex seems to be generated upon interaction of the cysteine rich and basic region of Tat and the gp120 V3 loop. AIMS: studies on the Tat and Env interaction by surface mapping and measurement of binding induced conformational changes by the assay of amino acids chemical reactivity changes. METHODS: chemical modification of cys and lys residues, proteolysis, HPLC, mass spectrometry. MAIN RESULTS: 4 disulfide bridges of 10 present in GP120 are accessible to reducing agents under mild conditions. These disulfides are found both in the monomeric GP120 and in trimeric GP140, and the binding of TAT does not modify the labelling pattern. Labelling of lys residues evidences 18 corresponding peptides in both GP120 and GP140, with 2 additional lys labelled in GP140, and the binding of TAT shields a single lys residue. CONCLUSIONS: Conformations of monomeric and trimeric ENV are very similar, the binding of TAT does not induce significant conformational changes. Protein studies on T. brucei T. brucei is a protozoan parasite responsible for African trypanosomiasis. Antigenic variation or intracellular parasitic life make prospects for vaccine development bleak. Only few drugs are available, which are however inadequate because of toxicity, inefficacy and resistance. However in recent years research has identified enzymes, other proteins and peculiar organelles as potential drug targets. Glycolysis, which in trypanosomatids takes place in specialized organelles called glycosomes, is considered a potential target because trypanosomes are completely dependent on it when living in the mammalian bloodstream. The pentose-phosphate pathway (PPP) is also very important since provides both NADPH for biosyntheses, detoxifications and protection against oxidative stress, and ribose for nucleotide biosynthesis. Glucose occurs in 2 anomeric forms: a-D-glucose and b-D-glucose. a- and b-anomers spontaneously interconvert but quite likely intercoversion is slow under intracellular conditions. Proteomic studies have identified a hexose-6-phosphate mutarotase (H6PM) in T. brucei. In all available exokinase crystal-structures containing glucose, the a-anomer was found. PGI is specific for a-G6P while G6PDH for b-G6P. It seems likely that H6PM plays an important role to provide the PPP with its substrate. AIMS: To well characterize the enzyme and assess its importance for the parasite in dealing with oxidative stress. METHODS: protein purification from recombinant bacteria, over-expressing the enzyme with a hystidine tail and kinetic studies. Knock-down of gene expression by RNA interference. Vitality analysis of RNAi bloodstream trypanosomes in presence or absence of H2O2. MAIN RESULTS: Knockdown shows a small effect on growth of bloodstreamform T. brucei under normal conditions, but dramatic effect when the cells are subjected to oxidative stress. The increased sensitivity to oxidative stress is similar to that in G6PDH-depleted cells. CONCLUSIONS: H6PM is important for oxidative defence, probably by accelerating anomeric conversion of G6P so its flux through PPP increases

Burden of Disease in PWH Harboring a Multidrug-Resistant Virus: Data from the PRESTIGIO Registry

Background: Currently, no data are available on the burden of morbidity and mortality in people with HIV-1 (PWH) harboring a 4-class drug-resistant (4DR) virus (nucleoside reverse transcriptase inhibitors, non-nucleoside reverse transcriptase inhibitors, protease inhibitors, integrase strand transfer inhibitors). The study aimed to assess the incidence of clinical events and death in this population. Methods: This was a cohort study on PWH from the PRESTIGIO Registry with a documented 4DR virus. Burden of disease was defined as the occurrence of any new event including an AIDS-defining event (ADE) or non-AIDS-defining event (NADE) or death from any cause after 4DR evidence (baseline). Cox regression models evaluated factors associated with the risk of new clinical events/death. Results: Among 148 PWH followed for a median (interquartile range) of 47 (32-84) months after 4DR evidence, 38 PWH had 62 new events or died from any cause (incidence rate, 9.12/100 person-years of follow-up; 95% CI = 6.85-11.39): 12 deaths (6 AIDS-related and 6 non-AIDS-related), 18 ADEs, 32 NADEs; 20 of the 38 NADEs (45%) of the incident clinical events were malignancies. The 4-year cumulative incidence of death was 6% (95% CI, 3%-13%), and that of ≥1 event or death was 22% (95% CI, 16%-31%). A higher risk of new clinical events/death was more likely in PWH with previous clinical events (adjusted hazard ratio [aHR], 2.67; 95% CI, 1.07-6.67) and marginally associated with lower baseline CD4+/CD8+ ratio (aHR, 0.82; 95% CI, 0.65-1.02). Conclusions: PWH harboring 4DR have a high burden of disease with a worrying incidence of malignancies, strongly advising for close prevention and monitoring interventions as well as access to innovative therapeutic strategies, especially in people with a history of clinical events and low CD4+/CD8+ ratio

Understanding Factors Associated With Psychomotor Subtypes of Delirium in Older Inpatients With Dementia

Objectives: Few studies have analyzed factors associated with delirium subtypes. In this study, we investigate factors associated with subtypes of delirium only in patients with dementia to provide insights on the possible prevention and treatments. Design: This is a cross-sectional study nested in the \u201cDelirium Day\u201d study, a nationwide Italian point-prevalence study. Setting and Participants: Older patients admitted to 205 acute and 92 rehabilitation hospital wards. Measures: Delirium was evaluated with the 4-AT and the motor subtypes with the Delirium Motor Subtype Scale. Dementia was defined by the presence of a documented diagnosis in the medical records and/or prescription of acetylcholinesterase inhibitors or memantine prior to admission. Results: Of the 1057 patients with dementia, 35% had delirium, with 25.6% hyperactive, 33.1% hypoactive, 34.5% mixed, and 6.7% nonmotor subtype. There were higher odds of having venous catheters in the hypoactive (OR 1.82, 95% CI 1.18-2.81) and mixed type of delirium (OR 2.23, CI 1.43-3.46), whereas higher odds of urinary catheters in the hypoactive (OR 2.91, CI 1.92-4.39), hyperactive (OR 1.99, CI 1.23-3.21), and mixed types of delirium (OR 2.05, CI 1.36-3.07). We found higher odds of antipsychotics both in the hyperactive (OR 2.87, CI 1.81-4.54) and mixed subtype (OR 1.84, CI 1.24-2.75), whereas higher odds of antibiotics was present only in the mixed subtype (OR 1.91, CI 1.26-2.87). Conclusions and Implications: In patients with dementia, the mixed delirium subtype is the most prevalent followed by the hypoactive, hyperactive, and nonmotor subtype. Motor subtypes of delirium may be triggered by clinical factors, including the use of venous and urinary catheters, and the use of antipsychotics. Future studies are necessary to provide further insights on the possible pathophysiology of delirium in patients with dementia and to address the optimization of the management of potential risk factors

Drug Prescription and Delirium in Older Inpatients: Results From the Nationwide Multicenter Italian Delirium Day 2015-2016

Objective: This study aimed to evaluate the association between polypharmacy and delirium, the association of specific drug categories with delirium, and the differences in drug-delirium association between medical and surgical units and according to dementia diagnosis. Methods: Data were collected during 2 waves of Delirium Day, a multicenter delirium prevalence study including patients (aged 65 years or older) admitted to acute and long-term care wards in Italy (2015-2016); in this study, only patients enrolled in acute hospital wards were selected (n = 4,133). Delirium was assessed according to score on the 4 "A's" Test. Prescriptions were classified by main drug categories; polypharmacy was defined as a prescription of drugs from 5 or more classes. Results: Of 4,133 participants, 969 (23.4%) had delirium. The general prevalence of polypharmacy was higher in patients with delirium (67.6% vs 63.0%, P =.009) but varied according to clinical settings. After adjustment for confounders, polypharmacy was associated with delirium only in patients admitted to surgical units (OR = 2.9; 95% CI, 1.4-6.1). Insulin, antibiotics, antiepileptics, antipsychotics, and atypical antidepressants were associated with delirium, whereas statins and angiotensin receptor blockers exhibited an inverse association. A stronger association was seen between typical and atypical antipsychotics and delirium in subjects free from dementia compared to individuals with dementia (typical: OR = 4.31; 95% CI, 2.94-6.31 without dementia vs OR = 1.64; 95% CI, 1.19-2.26 with dementia; atypical: OR = 5.32; 95% CI, 3.44-8.22 without dementia vs OR = 1.74; 95% CI, 1.26-2.40 with dementia). The absence of antipsychotics among the prescribed drugs was inversely associated with delirium in the whole sample and in both of the hospital settings, but only in patients without dementia. Conclusions: Polypharmacy is significantly associated with delirium only in surgical units, raising the issue of the relevance of medication review in different clinical settings. Specific drug classes are associated with delirium depending on the clinical setting and dementia diagnosis, suggesting the need to further explore this relationship

Drug prescription and delirium in older inpatients: Results from the nationwide multicenter Italian Delirium Day 2015-2016

Objective: This study aimed to evaluate the association between polypharmacy and delirium, the association of specific drug categories with delirium, and the differences in drug-delirium association between medical and surgical units and according to dementia diagnosis. Methods: Data were collected during 2 waves of Delirium Day, a multicenter delirium prevalence study including patients (aged 65 years or older) admitted to acute and long-term care wards in Italy (2015-2016); in this study, only patients enrolled in acute hospital wards were selected (n = 4,133). Delirium was assessed according to score on the 4 "A's" Test. Prescriptions were classified by main drug categories; polypharmacy was defined as a prescription of drugs from 5 or more classes. Results: Of 4,133 participants, 969 (23.4%) had delirium. The general prevalence of polypharmacy was higher in patients with delirium (67.6% vs 63.0%, P =.009) but varied according to clinical settings. After adjustment for confounders, polypharmacy was associated with delirium only in patients admitted to surgical units (OR = 2.9; 95% CI, 1.4-6.1). Insulin, antibiotics, antiepileptics, antipsychotics, and atypical antidepressants were associated with delirium, whereas statins and angiotensin receptor blockers exhibited an inverse association. A stronger association was seen between typical and atypical antipsychotics and delirium in subjects free from dementia compared to individuals with dementia (typical: OR = 4.31; 95% CI, 2.94-6.31 without dementia vs OR = 1.64; 95% CI, 1.19-2.26 with dementia; atypical: OR = 5.32; 95% CI, 3.44-8.22 without dementia vs OR = 1.74; 95% CI, 1.26-2.40 with dementia). The absence of antipsychotics among the prescribed drugs was inversely associated with delirium in the whole sample and in both of the hospital settings, but only in patients without dementia. Conclusions: Polypharmacy is significantly associated with delirium only in surgical units, raising the issue of the relevance of medication review in different clinical settings. Specific drug classes are associated with delirium depending on the clinical setting and dementia diagnosis, suggesting the need to further explore this relationship