Prolonged use of tenofovir in HIV/hepatitis B virus (HBV)-coinfected individuals does not lead to HBV polymerase mutations and is associated with persistence of lamivudine HBV polymerase mutations

Objectives

The aim of the study was to identify and characterize hepatitis B virus (HBV) polymerase gene mutations associated with ongoing HBV replication in HIV/HBV‐coinfected individuals receiving tenofovir (TDF).

Methods

This retrospective cross‐sectional study identified 28 HIV/HBV‐coinfected individuals who had received TDF for at least 3 months. All patients had samples available while receiving TDF (on‐TDF), and 24 also had samples available prior to treatment (pre‐TDF). Case records were reviewed to obtain clinical and virological data at the times of sampling (±3 months). The HBV DNA of all samples was amplified using polymerase chain reaction (PCR), and the polymerase region of PCR‐positive samples was sequenced and compared with reference HBV data.

Results

Of the pre‐TDF samples, 15 of 24 (63%) were HBV PCR positive. Of the on‐TDF samples, four of 28 (14%) were HBV PCR positive (mean time on TDF 13.5 months; range 3–23 months). Lamivudine (3TC)‐resistance mutations were detected in three of four (75%) of these viraemic samples. The previously identified putative TDF‐resistance mutations, rtA194T+rtL180M+rtM204V, were not detected in any individual.

Conclusions

Unique mutations in the HBV polymerase gene associated with TDF resistance are rare in HIV/HBV coinfection. 3TC‐resistance mutations persist and a significant proportion of patients are HBV PCR positive despite the addition of TDF.     

A novel protein tyrosine phosphatase gene is mutated in progressive myoclonus epilepsy of the Lafora type (EPM2)

Progressive myoclonus epilepsy of the Lafora type or Lafora disease (EPM2; McKusick no. 254780) is an autosomal recessive disorder characterized by epilepsy, myoclonus, progressive neurological deterioration and glycogen-like intracellular inclusion bodies (Lafora bodies). A gene for EPM2 previously has been mapped to chromosome 6q23- q25 using linkage analysis and homozygosity mapping. Here we report the positional cloning of the 6q EPM2 gene. A microdeletion within the EPM2 critical region, present inhomozygosis in an affected individual, was found to disrupt a novel gene encoding a putative protein tyrosine phosphatase (PTPase). The gene, denoted EPM2, presents alternative splicing in the 5' and 3' end regions. Mutational analysis revealed that EPM2 patients are homozygous for loss-of-function mutations in EPM2. These findings suggest that Lafora disease results from the mutational inactivation of a PTPase activity that may be important in the control of glycogen metabolism.      

Change in health knowledge of Bangladeshi children: five years experience

This article explores the improvement in the level of health knowledge of Bangladeshi children over a five year period 1993-1998. Data were generated from two nationally representative sample surveys covering respectively 2520 and 3360 children aged 11-12 y. Six health knowledge items, relevant to life in Bangladesh, were considered. Analyses revealed a significant improvement in the knowledge over the period. However, significant socio-economic variations also persisted in the performance. Rural children improved much faster compared to their urban counterparts. In both the surveys, children's performance varied significantly by items. To equip children with necessary health knowledge this study suggested strengthening health education at primary level in Bangladesh.     

Clinical and pathological features of pachyonychia congenita

Pachyonychia congenita (PC) is a rare genodermatosis affecting the nails, skin, oral mucosae, larynx, hair, and teeth. Pathogenic mutations in keratins K6a or K16 are associated with the PC-1 phenotype whereas K6b and K17 mutations are associated with the PC-2 phenotype. Analysis of clinical, pathological, and genetic data from the literature and two research registries reveal that >97% of PC cases exhibit fingernail and toenail thickening, and painful plantar keratoderma. Prospective evaluation of 57 PC patients from 41 families revealed variable clinical findings: hyperhidrosis (79%), oral leukokeratosis (75%), follicular keratosis (65%), palmar keratoderma (60%), cutaneous cysts (35%), hoarseness or laryngeal involvement (16%), coarse or twisted hair (26%), early primary tooth loss (14%), and presence of natal or prenatal teeth (2%). Stratification of these data by keratin mutation confirmed the increased incidence of cyst formation and natal teeth among PC-2 patients, although cysts were more commonly seen in PC-1 than previously reported (25%-33%). Previously unreported clinical features of PC include development of painful oral and nipple lesions during breastfeeding, copious production of waxy material in ears, and inability to walk without an ambulatory aid (50%). Possible pathogenic mechanisms are discussed with respect to the clinicopathologic and genetic correlations observed.     

Plasminogen kringle 5-engineered glioma cells block migration of tumor- associated macrophages and suppress tumor vascularization and progres- sion.

Angiostatin, a well-characterized angiostatic agent, is a proteolytic cleavage product of human plasminogen encompassing the first four kringle structures. The fifth kringle domain （K5） of human plasminogen is distinct from angiostatin and has been shown, on its own, to act as a potent endothelial cell inhibitor. We propose that tumor-targeted K5 cDNA expression may act as an effective therapeutic intervention as part of a cancer gene therapy strategy. In this study, we provide evidence that eukaryotically expressed His-tagged human K5 cDNA （hK5His） is exported extracellularly and maintains predicted disulfide bridging conformation in solution. Functionally, hK5His protein produced by retrovirally engineered human U87MG glioma cells suppresses in vitro migration of both human umbilical vein endothelial cells and human macrophages. Subcutaneous implantation of Matrigel-embedded hK5His-producing glioma cells in nonobese diabetic/severe combined immunodeficient mice reveals that hK5His indaces a marked reduction in blood vessel formation and signiticanfly suppresses the recruitment of tumor-infiltrating CD45（＋）Mac3（＋）Grl （-） macrophages. Therapeutically, we show ill a nude mouse orthotopic brain cancer model that tumor-targeted K5 expression is capable of effectively suppressing glioma growth and promotes significant long-term survival （〉120 days） of test animals. These data suggest that plasminogen K5 acts as a novel two-pronged anticancer agent, mediating its inhibitory effect via its action on host-derived endothelial cells and tumor-associated macrophages, resulting in a potent, clinically relevant antitumor effect.     

Melatonin, a potent agent in antioxidative defense: Actions as a natural food constituent, gastrointestinal factor, drug and prodrug

Melatonin, originally discovered as a hormone of the pineal gland, is also produced in other organs and represents, additionally, a normal food constituent found in yeast and plant material, which can influence the level in the circulation. Compared to the pineal, the gastrointestinal tract contains several hundred times more melatonin, which can be released into the blood in response to food intake and stimuli by nutrients, especially tryptophan. Apart from its use as a commercial food additive, supraphysiological doses have been applied in medical trials and pure preparations are well tolerated by patients. Owing to its amphiphilicity, melatonin can enter any body fluid, cell or cell compartment. Its properties as an antioxidant agent are based on several, highly diverse effects. Apart from direct radical scavenging, it plays a role in upregulation of antioxidant and downregulation of prooxidant enzymes, and damage by free radicals can be reduced by its antiexcitatory actions, and presumably by contributions to appropriate internal circadian phasing, and by its improvement of mitochondrial metabolism, in terms of avoiding electron leakage and enhancing complex I and complex IV activities. Melatonin was shown to potentiate effects of other antioxidants, such as ascorbate and Trolox. Under physiological conditions, direct radical scavenging may only contribute to a minor extent to overall radical detoxification, although melatonin can eliminate several of them in scavenger cascades and potentiates the efficacy of antioxidant vitamins. Melatonin oxidation seems rather important for the production of other biologically active metabolites such as N ¹-acetyl-N ²-formyl-5-methoxykynuramine (AFMK) and N ¹-acetyl-5-methoxykynuramine (AMK), which have been shown to also dispose of protective properties. Thus, melatonin may be regarded as a prodrug, too. AMK interacts with reactive oxygen and nitrogen species, conveys protection to mitochondria, inhibits and downregulates cyclooxygenase 2.