Genotype,serotype, and phylogenetic characterization of the complete genome sequence of hepatitis B virus isolates from Malawian chronic carriers of the virus

Hepatitis B virus (HBV) genotypes have distinct geographical distribution. HBV sequences among hepatitis B carriers in Malawi have not been evaluated thus far. HBsAg serotype and genotype of HBV was determined in 20 serum samples from Malawian chronic HBV carriers, and two complete genomes and 13 entire pre-S2/S genes were sequenced directly. Genotype A HBV isolates were found in all of the samples, and serotype with adw2 and ayw2 were detected in three and 17 samples, respectively. In phylogenetic analyses, two complete genomes were classified into a subgroup A' that was described previously in South African isolates of the virus, and were separated from HBV isolates in Western countries with nucleotide differences ranging from 4.1-6.2%. The separation of subgroup A' was also evident in the tree topology of the entire pre-S1/S2, X and precore/core region, but not evident in the small-S region. The nucleotide divergences in subgroup A' were higher than those among genotype A without subgroup A' in the complete genomes as well as each of four open reading frames. All of the 13 pre-S2/S sequences were classified into the subgroup A', and clustered with known HBV isolates with ayw2 in carriers from South Africa and Zimbabwe. Three amino acids in the pre-S2/S gene were characteristic of subgroup A' with ayw2. In conclusion, unique HBV isolates of subgroup A' with ayw2 are prevalent in Malawi, and subgroup A' with a relatively higher nucleotide diversity may be a HBV isolate characteristic of the indigenous population of some African countries.     

PX-RICS mediates ER-to-Golgi transport of the N-cadherin/beta-catenin complex

Cadherins mediate Ca2+-dependent cell-cell adhesion. Efficient export of cadherins from the endoplasmic reticulum (ER) is known to require complex formation with beta-catenin. However, the molecular mechanisms underlying this requirement remain elusive. Here we show that PX-RICS, a beta-catenin-interacting GTPase-activating protein (GAP) for Cdc42, mediates ER-to-Golgi transport of the N-cadherin/beta-catenin complex. Knockdown of PX-RICS expression induced the accumulation of the N-cadherin/beta-catenin complex in the ER and ER exit site, resulting in a decrease in cell-cell adhesion. PX-RICS was also required for ER-to-Golgi transport of the fibroblast growth factor-receptor 4 (FGFR4) associated with N-cadherin. PX-RICS-mediated ER-to-Golgi transport was dependent on its interaction with beta-catenin, phosphatidylinositol-4-phosphate (PI4P), Cdc42, and its novel binding partner gamma-aminobutyric acid type A receptor-associated protein (GABARAP). These results suggest that PX-RICS ensures the efficient entry of the N-cadherin/beta-catenin complex into the secretory pathway, and thereby regulates the amount of N-cadherin available for cell adhesion and FGFR4-mediated signaling.     

Neuropeptide Y modulates membrane excitability in neonatal rat mesencephalic V neurons

Neuropeptide Y (NPY) is one of a number of neuropeptides with powerful orexigenic effects. Intracerebroventricular administration of NPY induces increases in food intake and alters feeding rate. Besides it role in feeding behavior, NPY also has significant effects on neuronal systems related to other spontaneous behaviors such as rearing and grooming. In the present study, we examined the direct effects of NPY on mesencephalic V neurons (Mes V), which are important sensory neurons involved in oral motor reflexes and rhythmical jaw movements, as well as masticatory proprioception. Coronal brain slices were prepared from neonatal Sprague-Dawley rats (P3-17) and whole-cell patch clamp recordings were obtained from Mes V neurons. Bath application of NPY depolarized the membrane potential and induced inward current in most neurons. Application of NPY shortened the duration of the afterhyperpolarization following an action potential, and increased the mean spike frequency during repetitive discharge. In those neurons which exhibited rhythmical burst discharge in response to maintained current injection, the bursting frequency was also increased. These effects were mediated predominately by both Y1 and Y5 receptors.     

Evaluation of putative inhibitors of mitochondrial permeability transition for brain disorders — Specificity vs. toxicity

Inhibition of mitochondrial permeability transition (mPT) has emerged as a promising approach for neuroprotection and development of well-tolerated mPT inhibitors with favorable blood-brain barrier penetration is highly warranted. In a recent study, 28 clinically available drugs with a common heterocyclic structure were identified as mPT inhibitors e.g. trifluoperazine, promethazine and nortriptyline. In addition, neuroprotection by structurally unrelated drugs e.g. neurosteroids, 4-hydroxy-tamoxifen and trimetazidine has been attributed to direct inhibition of mPT. The regulation of mPT is complex and highly dependent on the prevailing experimental conditions. Several features of mPT, such as swelling, depolarization or NADH oxidation, can also occur independently of the mPT phenomenon. Here, in isolated rodent brain-derived and human liver mitochondria, we re-evaluate drugs promoted as potent mPT inhibitors. We address the definition of an mPT inhibitor and present strategies to reliably detect mPT inhibition in vitro. Surprisingly, none of the 12 compounds tested displayed convincing mPT inhibition or effects comparable to cyclophilin D inhibition by the non-immunosuppressive cyclophilin inhibitor D-MeAla³-EtVal⁴-Cyclosporin (Debio 025). Propofol and 2-aminoethoxydiphenyl borate (2-APB) inhibited swelling in de-energized mitochondria but did not increase calcium retention capacity (CRC). Progesterone, trifluoperazine, allopregnanolone and 4-hydroxy-tamoxifen dose-dependently reduced CRC and respiratory control and were thus toxic rather than beneficial to mitochondrial function. Interestingly, topiramate increased CRC at high concentrations likely by a mechanism separate from direct mPT inhibition. We conclude that a clinically relevant mPT inhibitor should have a mitochondrial target and increase mitochondrial calcium retention at concentrations which can be translated to human use.     

Transplantation-associated thrombotic microangiopathy after steroid pulse therapy for polyserositis related to graft-versus-host disease

Transplantation-associated thrombotic microangiopathy (TA-TMA) is a rare but devastating syndrome that occurs in allogeneic hematopoietic stem cell transplant recipients, and is associated with a variety of transplantation-related factors, including conditioning regimens, immunosuppressive agents, graft-versus-host disease (GVHD) and opportunistic infections. TA-TMA has an unfavorable prognosis and responds poorly to conventional treatment including plasma exchange (PE). We present a case of a 37-year-old man with membranous nephropathy (MN) and polyserositis caused by GVHD after hematopoietic stem cell transplantation. He developed TA-TMA after steroid pulse therapy for polyserositis. We treated the patient with PE and mycophenolate mofetil (MMF) after which the TA-TMA successfully improved and the MN underwent complete remission. The present case suggests that corticosteroids with severe GVHD might increase the risk of TA-TMA, and that PE in combination with MMF may be a valuable therapy to improve the prognosis.     

Ubiquitin‐negative,eosinophilic neuronal cytoplasmic inclusions associated with stress granules and autophagy: An immunohistochemical investigation of two cases

Identification of the proteinaceous components of the pathological inclusions is an important step in understanding the associated disease mechanisms. We immunohistochemically examined two previously reported cases with eosinophilic neuronal cytoplasmic inclusions (NCIs) (case 1, Mori et al. Neuropathology 2010; 30: 648–53; case 2, Kojima et al. Acta Pathol Jpn 1990; 40: 785–91) using 67 antibodies against proteins related to cytoskeletal constituents, ubiquitin‐proteasome system, autophagy‐lysosome pathway and stress granule formation. Regional distribution pattern of eosinophilic NCIs in case 1 was substantially different from that in case 2. However, NCIs in both cases were immunonegative for ubiquitin and p62 and were immunopositive for stress granule markers as well as autophagy‐related proteins, including valosin‐containing protein. Considering that eukaryotic stress granules are cleared by autophagy and valosin‐containing protein function, our findings suggest that eosinophilic NCIs in the present two cases may represent the process of autophagic clearance of stress granules.     

Vasovagal syncope with asystole associated with intravenous access.

Two cases of vasovagal syncope (VVS) during venous access are reported. Both patients had a history of fainting episodes and experienced bradycardia with asystole, hypotension, and fainting. Pain and phobic stress during venous access triggered an increase in parasympathetic tone, resulting in bradycardia with asystole and hypotension in both cases. Hypotension and bradycardia likely caused cerebral hypoperfusion, leading to fainting. The intense parasympathetic tone triggered by somatic or emotional stress was likely responsible for directly depressing the sinus node, leading to asystole and bradycardia. Bradycardia with asystole progressing to syncope is a potentially fatal dysrhythmia in patients with cardiovascular disease or older patients with decreased cardiac function. Appropriate treatment for VVS includes the administration of intravenous fluids, vagolytics, ephedrine, and the rapid use of the Trendelenburg position. Intravenous fluids and atropine were used to treat the present patients.     

Predictors of hypofibrinogenemia in blunt trauma patients on admission

Purpose

Massive bleeding usually leads to critically low levels of clotting factors, including fibrinogen. Although reduced fibrinogen levels correlate with increased mortality, predictors of hypofibrinogenemia have remained poorly understood. We investigated whether findings available on admission can be used as predictors of hypofibrinogenemia.

Methods

We retrospectively reviewed serum fibrinogen levels tested on arrival in 290 blunt trauma patients transported to a level I trauma center during a 3-year period. The primary outcome was prehospital predictors for hypofibrinogenemia. Covariates included age, sex, prehospital fluid therapy, prehospital anatomical and physiological scores, time from injury, base excess, and lactate on arrival. All variables with values of p < 0.10 in univariate analysis were included in a multivariate logistic regression model. The relationships between the variables and the 7-day mortality rate were evaluated in a Cox proportional hazards model.

Results

Patient’s age [odds ratio (OR): 0.97, p < 0.001], Triage Revised Trauma Score (T-RTS) (OR: 0.81, p = 0.003), and prehospital fluid therapy (OR: 2.54, p = 0.01) were detected as independent predictors for hypofibrinogenemia in multivariate logistic regression analysis. Serum fibrinogen level [hazard ratio (HR): 0.99, p = 0.01] and T-RTS (HR: 0.77, p < 0.01) were associated with the 7-day mortality rate.

Conclusion

T-RTS is considered to play an important role in predicting hypofibrinogenemia and 7-day mortality in blunt trauma patients.

     

Activated platelets in transient global amnesia and TIA

To assess whether platelets are activated in transient global amnesia (TGA) and TIA, blood samples were analyzed by fluorescence-activated cytoscan using antibodies specific for platelet fibrinogen receptor (PAC1) and P-selectin (CD62P). Samples from TIA contained high levels of CD62P compared with age-matched control subjects, whereas those from TGA did not. The authors suggest that activated platelets are involved in brain ischemia, whereas ischemia appears not to be associated with most TGA.