Potential Mutations Associated With Occult Hepatitis B Virus Status

Context:

Occult hepatitis B virus (HBV) status (OHBS) is simply defined as the presence of HBV DNA in the liver (with or without detectable HBV DNA in the serum), in the absence of serum HBV surface antigen (HBsAg). Importance of OHBS is mostly clinical, related to its possible role in spreading through blood transfusion and liver transplantation; causing classic forms of HBV. Mechanisms underlying this entity are poorly defined. Several possibilities have been suggested, with major classification into two groups: defective host immune response and viral replication activity through mutations of HBV DNA sequence. Mutations are extensively investigated in all four overlapping open reading frames (ORFs) of HBV genome, to define their possible role in the pathogenesis of OHBS. Some of these mutations like S-escape mutants could not be detected by the routine available assays, making them difficult to diagnosis. Therefore, trying to detect this covert condition could be more helpful for defining better preventive and therapeutic strategies.

Evidence Acquisition:

In the present study we provided an in-depth review of the most important new data available on different mutations in HBV genome of patients with OHBS, which may play a role in the pathogenesis of OHBS. The data were collected through reviewing the full-text articles, identified by the PubMed search, using the following keywords and their different combinations: occult hepatitis B, HBV genome, "a" determinant, HBV open reading frames, S mutations, X mutations, P mutations and C mutations.

Results:

Variants within the major hydrophilic region (MHR) of the HBsAg, deletions in the pre-S1region, codon stop in the S open reading frames (ORF), sporadic non common mutations, some mutations affecting the posttranslational production of HBV proteins in the S ORF like deletion mutations, mutations in start codon and nucleotide changes in the X ORF, deletion and point mutations in P ORF and sometimes, nucleotide substitution in the C ORF are among the assumed mutations detected to have a role in OHBS appearance.

Conclusions:

Studies mostly lacked a control group and the whole-length HBV sequencing was scant with conflicting results, suggesting that OHBS is often a result of multiple mechanisms. Additional studies on full-length HBV genomes from occult and non-occult HBV cases may shed more light on the interplay between different mechanisms involved in the pathogenesis of OHBS.     

Increased susceptibility to hypertensive renal disease in streptozotocin-treated diabetic rats is not modulated by salt intake

Aims/hypothesis  

In early type 1 diabetes mellitus, renal salt handling is dysregulated, so that the glomerular filtration rate becomes inversely proportional to salt intake. The salt paradox occurs in both humans and rats and, with low salt intake, results in diabetic hyperfiltration. We tested whether increased salt intake could reduce the susceptibility to injury of non-clipped kidneys in diabetic rats with pre-existing Goldblatt hypertension.     

CXCR4 gene transfer prevents pressure overload induced heart failure

Stem cell and gene therapies are being pursued as strategies for repairing damaged cardiac tissue following myocardial infarction in an attempt to prevent heart failure. The chemokine receptor-4 (CXCR4) and its ligand, CXCL12, play a critical role in stem cell recruitment post-acute myocardial infarction. Whereas progenitor cell migration via the CXCL12/CXCR4 axis is well characterized, little is known about the molecular mechanisms of CXCR4 mediated modulation of cardiac hypertrophy and failure. We used gene therapy to test the effects of CXCR4 gene delivery on adverse ventricular remodeling due to pressure overload. We assessed the effect of cardiac overexpression of CXCR4 during trans-aortic constriction (TAC) using a cardiotropic adeno-associated viral vector (AAV9) carrying the CXCR4 gene. Cardiac overexpression of CXCR4 in mice with pressure overload prevented ventricular remodeling, preserved capillary density and maintained function as determined by echocardiography and in vivo hemodynamics. In isolated adult rat cardiac myocytes, CXCL12 treatment prevented isoproterenol induced hypertrophy and interrupted the calcineurin/NFAT pathway. Finally, a complex involving the L-type calcium channel, β2-adrenoceptor, and CXCR4 (Cav1.2/β2AR/CXCR4) was identified in healthy cardiac myocytes and was shown to dissociate as a consequence of heart failure. CXCR4 administered to the heart via gene transfer prevents pressure overload induced heart failure. The identification of CXCR4 participation in a Cav1.2-β2AR regulatory complex provides further insight into the mechanism by which CXCR4 modulates calcium homeostasis and chronic pressure overload responses in the cardiac myocyte. Together these results suggest that AAV9.CXCR4 gene therapy is a potential therapeutic approach for congestive heart failure.     

Histological evaluation of healing after transalveolar maxillary sinus augmentation with bioglass and autogenous bone

Objectives: The aim was to evaluate histologically the outcome of a bioglass and autogenous bone (at 1 : 1 ratio) composite implantation for transalveolar sinus augmentation. Methods: In 31 patients, during implant installation ca. 4 months after sinus augmentation, biopsies were harvested through the transalveolar osteotomy by means of a trephine bur and non‐decalcified sections through the long axis of the cylinder were produced. After a strict selection process, taking into account the presurgical residual bone height and biopsy length, 8 and 15 biopsies representing the new tissues formed inside the sinus and the transalveolar osteotomy, respectively, qualified for analysis. The tissue fractions occupied by newly formed bone (mineralized tissue+bone marrow), soft connective tissue, residual biomaterial+empty spaces, and debris inside the sinus cavity or the transalveolar osteotomy were estimated. Results: Bone and connective tissue fraction in the newly formed tissues inside the sinus cavity averaged 23.4 ± 13.2% and 54.1 ± 23.5%, respectively. Residual biomaterial, empty spaces, and debris averaged 1.9 ± 3.5%, 10.5 ± 6.3%, and 8.4 ± 14.5%, respectively. In the transalveolar osteotomy, bone and connective tissue fraction averaged 41.6 ± 14.3% and 46.1 ± 13%, respectively, while the amount of residual biomaterial, empty spaces, and debris was 2.8 ± 5%, 4.7 ± 1.9%, and 3.2 ± 2.6%, respectively. Statistically significant differences between the sinus cavity and the transalveolar osteotomy were found only for bone and empty spaces' values (P=0.02 and 0.04, respectively). Conclusion: Sinus augmentation with a bioglass and autogenous bone composite is compatible with bone formation that, in a short distance from the floor of the sinus, shows similar density as that reported previously for other commonly used bone substitutes. New bone fraction inside the transalveolar osteotomy was almost twice as much as in the sinus cavity, while the amount of residual biomaterial was much less than that inside the sinus. To cite this article :
Stavropoulos A, Sima C, Sima A, Nyengaard J, Karring T, Sculean A. Histological evaluation of healing after transalveolar maxillary sinus augmentation with bioglass and autogenous bone.
Clin. Oral Impl. Res. 23 , 2012; 125–131.
doi: 10.1111/j.1600‐0501.2011.02161.x     

Efficacy of HIV/STI Behavioral Interventions for Heterosexual African American Men in the United States: A Meta-Analysis

This meta-analysis estimates the overall efficacy of HIV prevention interventions to reduce HIV sexual risk behaviors and sexually transmitted infections (STIs) among heterosexual African American men. A comprehensive search of the literature published during 1988-2008 yielded 44 relevant studies. Interventions significantly reduced HIV sexual risk behaviors and STIs. The stratified analysis for HIV sexual risk behaviors indicated that interventions were efficacious for studies specifically targeting African American men and men with incarceration history. In addition, interventions that had provision/referral of medical services, male facilitators, shorter follow-up periods, or emphasized the importance of protecting family and significant others were associated with reductions in HIV sexual risk behaviors. Meta-regression analyses indicated that the most robust intervention component is the provision/referral of medical services. Findings indicate that HIV interventions for heterosexual African American men might be more efficacious if they incorporated a range of health care services rather than HIV/STI-related services alone.     

年龄相关性白内障患者14万例角膜前表面散光的分布特征

目的分析中国18家医院的14万例年龄相关性白内障患者角膜前表面散光的分布特征。方法回顾性系列病例研究。连续性收集2015年7月至2018年10月于中国18家爱尔眼科医院就诊的40岁以上年龄相关性白内障患者143889例(143889只右眼)的眼部生物学参数资料。角膜前表面散光度数和轴向、前房深度、角膜屈光力、眼轴长度等眼球参数采用IOLMaster 500测量,获取3次测量结果的平均值。各医院将资料整理分析后提交给武汉爱尔眼科医院进行总体分析。非正态分布数据以M(P25~P75)表示;采用Mann-Whitney检验、Kruskal-Wallis检验、χ²检验等分析角膜前表面散光度数和轴向在不同性别、年龄、前房深度、角膜屈光力、眼轴长度中的分布差异。结果143889例患者中女性84319例,男性59570例;年龄为72(65~78)岁;角膜散光度数为0.84(0.51~1.33)D,散光度数≥0.75 D者80895例(56.22%),散光度数≥1.00 D者57304例(39.83%)。女性角膜散光度数为0.87(0.53~1.37)D,男性为0.82(0.50~1.29)D(U=-14.891);女性顺规散光比例为33.26%(28046/84319),逆规散光比例为49.08%(41385/84319);男性顺规散光比例为34.26%(20408/59570),逆规散光比例为46.91%(27945/59570)(χ²=70.913),差异均有统计学意义(均P<0.05)。随年龄增加,角膜散光度数先由0.94(0.57~1.48)D减少至0.75(0.46~1.18)D,后又增大至1.19(0.74~1.79)D,差异有统计学意义(H=1263.438,P<0.05),变化的转折在61~70岁。随着年龄的增大,顺规散光比例减小[由77.50%(396/511)减少至12.50%(3/24)],逆规散光比例增大[由11.15%(57/511)增大至79.07%(34/43)],斜向散光比例变化不大[17.02%(16/94)至19.92%(245/1230)],分布差异有统计学意义(χ²=10174.496,P<0.05)。前房越浅,角膜散光度数越大,由0.82(0.51~1.31)D增大至1.05(0.61~1.56)D;逆规散光比例越大,由47.32%(60207/127227)增大至51.69%(184/356),差异均有统计学意义(H=409.961,χ2=120.995;均P<0.05)。平均角膜屈光力越大,角膜散光度数越大,由0.80(0.49~1.33)D增大至0.95(0.58~1.53)D;逆规散光比例越小,由52.84%(4963/9392)减小至39.97%(9023/22577),差异均有统计学意义(H=808.562,χ²=752.147;均P<0.05)。不同眼轴长度相比,当眼轴长度>25.00 mm时,角膜散光度数最大,为1.04(0.62~1.65)D;逆规散光比例最大,为49.00%(10964/22376),差异均有统计学意义(H=2071.198,χ²=131.130;均P<0.05)。结论年龄相关性白内障患者角膜前表面散光轴向以逆规散光为主。随着年龄的增大,角膜散光度数有先减小后增加的趋势。65岁为顺规散光向逆规散光变化的转折点。前房越浅,角膜前表面散光度数以及逆规散光比例越大。当眼轴长度>25.00 mm时,角膜前表面散光度数和逆规散光比例最大。     

Correction: Regulation of nitrogen dynamics at the sediment–water interface during HAB degradation and subsequent reoccurrence

Correction for ‘Regulation of nitrogen dynamics at the sediment–water interface during HAB degradation and subsequent reoccurrence’ by Weiping Sima et al., RSC Adv., 2020, 10, 13480–13488, DOI: 10.1039/c9ra10673a.

The authors regret that the affiliations of three of the authors (Hong Li, Hainan Ai and Hao Zhan) were shown incorrectly in the original article. The corrected author list and affiliations are as shown above.The Royal Society of Chemistry apologises for these errors and any consequent inconvenience to authors and readers.     

Regulation of nitrogen dynamics at the sediment–water interface during HAB degradation and subsequent reoccurrence

The effects of harmful algal blooms (HABs) on nutrient dynamics have been extensively studied; however, the response of nitrogen to continuous HAB degradation and subsequent reoccurrence is not well understood. Here, a small-scale experiment was conducted to assess how nitrogen in the sediment–water interface (SWI) responds to HAB degradation and subsequent reoccurrence at different initial algal densities. The results showed that during the algae decomposition stage, the NH₄⁺–N flux of the SWI remained positive but decreased with the increase in algal density from 3.5 × 10⁷ to 2.3 × 10⁸ cells per L, indicating that the sediment was the source of NH₄⁺–N. In contrast, the deposit was a sink of NO₃⁻–N. However, during the reoccurrence of HAB, the distribution of NH₄⁺–N and NO₃⁻–N fluxes was completely converted. Nitrogen flux analysis throughout algae decomposition and reoccurrence indicated that although the sediment acted as a sink of nitrogen, the flux was dependent on the initial algal density. Our results confirmed that algae decomposition and reoccurrence would greatly affect the nitrogen cycle of the SWI, during which dissolved oxygen (DO) and initial algal density dominated. This study is the first to show that the regulation of nitrogen flux and migration changes during continuous HAB decomposition and subsequent reoccurrence.

The effects of harmful algal blooms (HABs) on nutrient dynamics have been extensively studied; however, the response of nitrogen to continuous HAB degradation and subsequent reoccurrence is not well understood.     

Phenotypic detection of Klebsiella pneumoniae carbapenemase among burns patients: First report from Iran

Background

Resistance to antimicrobial agents such as carbapenems among enterobacteriacea has been increasing, especially in Klebsiella pneumonia that produces variety of enzymes including Klebsiella pneumoniae carbapenemase (KPC). This study is the first report of its kind investigating the resistance to carbapenems among burns patients in Iran.

Method

During a 6-month period, 28 hospitalized burn patients who required to be placed on broad spectrum antibiotics were studied. Isolated species identified by routine biochemical test. Susceptibility testing for these species was performed by recommended the CLSI guidelines method. The tested antibiotics included cefotaxime, cefepime, aztreonam, imipenem, amoxicillin + clavulonic acid, gentamicin, amikacin, tobramycin, tetracycline, and trimethoprim-sulfamethoxazole, and chloramphenicol. For determination of KPC in phenotypical forms, Modified Hodge Test was utilized as per CLSI recommendation.

Results

Thirty-five Klebsiella spp. were isolated from 28 hospitalized patients. Nineteen out of 35 Klebsiella isolates were resistant to imipenem and that all of them had positive KPC. Nine of imipenem resistant isolates were also resistant to all tested antibiotics. Mortality rate among patients with positive KPC was 33%.

Conclusion

High rate of multi-drug resistant (MDR) strains in isolates with positive KPC is a major challenge in Iran and that it could cause an increase in both mortality and morbidity among burn patients. Thus, appropriate infection control measures and guidelines are needed to prevent such infections among burn patients.