Role of CT and MRI in the preoperative evaluation of auditory brainstem implantation in patients with congenital inner ear pathology

PURPOSE: The purpose of this study was to evaluate the reliability of computed tomography (CT) and magnetic resonance imaging (MRI) in characterising cochlear nerve anomalies in auditory brainstem implant candidates with congenital hearing loss. MATERIALS AND METHODS: Seventeen patients affected by congenital sensorineural hearing loss were examined by CT and MRI. Inner ear malformations eligible for auditory brainstem implants were classified according to the Casselman classification. All patients subsequently received auditory brainstem implants. RESULTS: Suspected congenital anomalies were confirmed by CT and MRI in all 17 patients. There were 5/17 bilateral cochlear nerve aplasias and 12/17 cochleovestibular anomalies. Of these, 5/12 patients had a common cochleovestibular cavity, 2/12 had bilateral cochlear aplasia and cochlear nerve agenesis, 1/12 had type I incomplete partition, 2/12 had type II incomplete partition and 2/12 had cochlear hypoplasia. CONCLUSIONS: Preoperative CT and MRI assessment of patients with sensorineural hearing loss is reliable. MRI provided additional information, identifying the possible absence of cochlear nerve and excluding other central nervous system (CNS) diseases.     

Homocysteine levels and sustained virological response to pegylated‐interferon α2b plus ribavirin therapy for chronic hepatitis C: a prospective study

Background: Chronic hepatitis C affects about 3% of the world's population. Pegylated interferon (IFN) α plus ribavirin is the gold standard treatment. Methylenetetrahydrofolate reductase(MTHFR) is a key enzyme in the metabolism of homocysteine. MTHFR gene polymorphisms and high levels of homocysteine are associated with a high degree of steatosis and fibrosis, conditions associated with a low sustained virological response (SVR) rate. Aims: To evaluate whether MTHFR polymorphisms and homocysteine levels are predictors of the outcome of treatment in 102 prospectively enrolled patients with chronic hepatitis C naive to treatment. Methods: Patients were treated with pegylated interferon α‐2b plus ribavirin. All patients underwent blood tests, assessment of homocysteine, vitamin B₁₂, folate, hepatitis C virus (HCV)‐RNA levels, screening for MTHFR gene polymorphisms and liver ultrasound examination. Results: Homocysteine levels were deranged (>16 μmol/L) in 10.5% of MTHFR wild‐type patients vs 40.3% of non‐wild‐type patients (P=0.015). Homocysteine levels were 14.4 μmol/L in SVR patients and 15.5 μmol/L in non‐SVR patients (P=0.049). The SVR rate was 40.0% in MTHFR wild‐type patients, 52.0% in heterozygote mutants and 39.3% in homozygote mutants (P=0.467). At logistic regression analysis, genotypes 2 and 3 (odds ratio: 12.328, 95% confidence interval: 3.390–44.837, P=0.0001), homocysteine <16 μmol/L (odds ratio: 3.397, 95% confidence interval: 1.033–11.177, P=0.044) and aspartate aminotransferase (AST) levels <48 U/L (odds ratio: 3.262, 95% confidence interval: 1.125–9.458, P=0.029) were independent predictors of SVR. Conclusions: In patients with chronic hepatitis C, homocysteine levels are associated with the outcome of pegylated‐IFNα plus ribavirin treatment, while polymorphisms of MTHFR are not.     

The Cardiovascular Effect of the Uremic Solute Indole-3 Acetic Acid

In CKD, uremic solutes may induce endothelial dysfunction, inflammation, and oxidative stress, leading to increased cardiovascular risk. We investigated whether the uremic solute indole-3 acetic acid (IAA) predicts clinical outcomes in patients with CKD and has prooxidant and proinflammatory effects. We studied 120 patients with CKD. During the median study period of 966 days, 29 patients died and 35 experienced a major cardiovascular event. Kaplan–Meier analysis revealed that mortality and cardiovascular events were significantly higher in the higher IAA group (IAA>3.73 µM) than in the lower IAA group (IAA<3.73 µM). Multivariate Cox regression analysis demonstrated that serum IAA was a significant predictor of mortality and cardiovascular events after adjustments for age and sex; cholesterol, systolic BP, and smoking; C-reactive protein, phosphate, body mass index, and albumin; diastolic BP and history of cardiovascular disease; and uremic toxins p-cresyl sulfate and indoxyl sulfate. Notably, IAA level remained predictive of mortality when adjusted for CKD stage. IAA levels were positively correlated with markers of inflammation and oxidative stress: C-reactive protein and malondialdehyde, respectively. In cultured human endothelial cells, IAA activated an inflammatory nongenomic aryl hydrocarbon receptor (AhR)/p38MAPK/NF-κB pathway that induced the proinflammatory enzyme cyclooxygenase-2. Additionally, IAA increased production of endothelial reactive oxygen species. In conclusion, serum IAA may be an independent predictor of mortality and cardiovascular events in patients with CKD. In vitro, IAA induces endothelial inflammation and oxidative stress and activates an inflammatory AhR/p38MAPK/NF-κB pathway.     

Fosamprenavir/ritonavir in patients with viral hepatitis coinfection: an observational multicohort study

Objective: Safety and tolerability evaluation of adapted dose regimens containing fosamprenavir/ritonavir (FPV/r) in HIV-infected subjects with viral hepatitis co-infection.

Methods: A retrospective multicohort analysis was conducted. Subjects from three European cohorts who started FPV/r or lopinavir/ritonavir (LPV/r) as a comparator contributed data to a centralized database. Subjects were divided into five groups by treatment regimen and level of hepatic impairment (aspartate aminotransferase [AST] platelet ratio index [APRI] score < or ≥2). Multivariable Cox regression analyses controlling for demographic factors, baseline CD4 count, FIB-4 score, use of antiretroviral therapy, and laboratory markers (bilirubin and platelet count) were performed to identify factors independently associated with risk of developing adverse events or safety events (eg, drug discontinuation, alanine aminotransferase (ALT) elevation, hepatic decompensation/death).

Results: A total of 1096 patients contributed data to the study. Fosamprenavir/ritonavir (except in subjects with APRI ≥2 receiving standard dose) was associated with a higher two-year risk of drug discontinuation compared with LPV/r. Restricting the analysis to discontinuations due to adverse events (AEs), only subjects who received the reduced dose were more likely to discontinue ≥1 drug in the FPV/r regimen. There were no statistical differences in ALT elevation between groups. Incidence of hepatic decompensation events was similar among groups except for subjects who received non standard doses of FPV, though the number of events was small.

Conclusions: Fosamprenavir/ritonavir discontinuation rate due to AEs or ALT elevation was similar across all European-approved FPV/r doses and to that of LPV/r subjects. Although liver tolerated antiretrovirals, such as integrase inhibitor and entry inhibitor, the use of FPV/r is acceptable in HIV infected patients with viral hepatitis.     

Effects of glucagon on systemic and splanchnic circulation in conscious rats with biliary cirrhosis

To elucidate the relationship between the haemodynamic changes and glucagon in cirrhosis, we infused physiologic and supraphysiologic doses of this hormone in conscious rats with portal hypertension due to biliary cirrhosis. Cardiac output and splanchnic organ blood flows were measured by the radioactive microsphere method before and 30 min after glucagon infusion at doses of 2, 5 and 10 ng/min. Serum glucagon increased from a basal level of 92 +/- 17 pg/ml (mean +/- S.E.) to 399 +/- 89, 1151 +/- 136 and 2064 +/- 328 pg/ml, respectively, in sham-operated rats, and from 743 +/- 75 pg/ml to 1497 +/- 197, 1583 +/- 356 and 2957 +/- 649 pg/ml, respectively, in cirrhotic animals at 2, 5 and 10 ng/min doses. In both groups, cardiac output did not change after glucagon infusion at 2 and 5 ng/min doses, suggesting that factors other than glucagon are primarily responsible for the systemic hyperdynamic circulation in cirrhosis. Portal tributary blood flow increased significantly after glucagon infusion in sham-operated rats by 34 and 65% at doses of 5 ng/ml and 10 ng/ml, respectively, and in cirrhotic rats by 29% at a dose of 10 ng/ml. However, portal tributary blood flow did not change after glucagon infusion at the physiologic dose of 2 ng/min. This study shows that glucagon infused at a physiologic dose does not increase splanchnic blood flow, although it increases portal tributary blood flow at supraphysiologic doses. The discrepancy between blood glucagon levels and splanchnic haemodynamic responses suggests that glucagon plays only a minor role and that other factors are primarily responsible for the hyperdynamic state of the splanchnic circulation in rats with biliary cirrhosis.     

Endovascular treatment of bronchial artery aneurysm with aortic stent-graft placement and coil embolization

Bronchial artery aneurysm (BAA) represents a rare, but dangerous, pathology because its rupture can cause a life-threatening hemorrhage; opportune treatment is mandatory when a definite diagnosis is obtained. There are several reports of endovascular treatment of BAA with transcatheter arterial embolization and only few cases treated with aortic stent-graft exclusion. We report a case of mediastinal BAA close to thoracic aorta treated with a combined approach of stent-graft occlusion of the inflow and coil embolization of the outflow arteries.     

Nucleation of calcium oxalate crystals by albumin: involvement in the prevention of stone formation

BACKGROUND: Urine is supersaturated in calcium oxalate, which means that it will contain calcium oxalate crystals that form spontaneously. Their size must be controlled to prevent retention in ducts and the eventual development of a lithiasis. This is achieved, in part, by specific inhibitors of crystal growth. We investigated whether promoters of crystal nucleation could also participate in that control, because for the same amount of salt that will precipitate from a supersaturated solution, increasing the number of crystals will decrease their average size and facilitate their elimination. METHODS: Albumin was purified from commercial sources and from the urine of healthy subjects or idiopathic calcium stone formers. Its aggregation properties were characterized by biophysical and biochemical techniques. Albumin was then either attached to several supports or left free in solution and incubated in a metastable solution of calcium oxalate. Kinetics of calcium oxalate crystallization were determined by turbidimetry. The nature and efficiency of nucleation were measured by examining the type and number of neoformed crystals. RESULTS: Albumin, one of the most abundant proteins in urine, was a powerful nucleator of calcium oxalate crystals in vitro, with the polymers being more active than monomers. In addition, nucleation by albumin apparently led exclusively to the formation of calcium oxalate dihydrate crystals, whereas calcium oxalate monohydrate crystals were formed in the absence of albumin. An analysis of calcium oxalate crystals in urine showed that the dihydrate form was present in healthy subjects and stone formers, whereas the monohydrate, which is thermodynamically more stable and constitutes the core of most calcium oxalate stones, was present in stone formers only. Finally, urinary albumin purified from healthy subjects contained significantly more polymers and was a stronger promoter of calcium oxalate nucleation than albumin from idiopathic calcium stone formers. CONCLUSIONS: Promotion by albumin of calcium oxalate crystallization with specific formation of the dihydrate form might be protective, because with rapid nucleation of small crystals, the saturation levels fall; thus, larger crystal formation and aggregation with subsequent stone formation may be prevented. We believe that albumin may be an important factor of urine stability.     

Highly potent,fully recombinant anti-HIV chemokines: Reengineering a low-cost microbicide

New prevention strategies for use in developing countries are urgently needed to curb the worldwide HIV/AIDS epidemic. The N-terminally modified chemokine PSC-RANTES is a highly potent entry inhibitor against R5-tropic HIV-1 strains, with an inhibitory mechanism involving long-term intracellular sequestration of the HIV coreceptor, CCR5. PSC-RANTES is fully protective when applied topically in a macaque model of vaginal HIV transmission, but it has 2 potential disadvantages related to further development: the requirement for chemical synthesis adds to production costs, and its strong CCR5 agonist activity might induce local inflammation. It would thus be preferable to find a recombinant analogue that retained the high potency of PSC-RANTES but lacked its agonist activity. Using a strategy based on phage display, we set out to discover PSC-RANTES analogs that contain only natural amino acids. We sought molecules that retain the potency and inhibitory mechanism of PSC-RANTES, while trying to reduce CCR5 signaling to as low a level as possible. We identified 3 analogues, all of which exhibit in vitro potency against HIV-1 comparable to that of PSC-RANTES. The first, 6P4-RANTES, resembles PSC-RANTES in that it is a strong agonist that induces prolonged intracellular sequestration of CCR5. The second, 5P12-RANTES, has no detectable G protein-linked signaling activity and does not bring about receptor sequestration. The third, 5P14-RANTES, induces significant levels of CCR5 internalization without detectable G protein-linked signaling activity. These 3 molecules represent promising candidates for further development as topical HIV prevention strategies.