Influence of sex chromosome constitution on the genomic imprinting of germ cells

Germ cells in XY male mice establish site-specific methylation on imprinted genes during spermatogenesis, whereas germ cells in XX females establish their imprints in growing oocytes. We showed previously that in vitro, sex-specific methylation patterns of pluripotent stem cell lines derived from germ cells were influenced more by the sex chromosome constitution of the cells themselves than by the gender of the embryo from which they had been derived. To see whether the same situation would prevail in vivo, we have now determined the methylation status of H19 expressed from the maternal allele, and the expression and methylation status of a paternally expressed gene Peg3, in germ cells from sex-reversed and control embryos. For these imprinted genes, we conclude that the female imprint is a response of the germ cells to undergoing oogenesis, rather than to their XX chromosome constitution. Similarly, both our XY and our sex-reversed XX male germ cells clearly showed a male rather than a female pattern of DNA methylation; here, however, the sex chromosome constitution had a significant effect, with XX male germ cells less methylated than the XY controls.     

Neurofibromatosis type I with breast cancer: not only for women!

The association of neurofibromatosis type I with invasive male breast cancer is a rare clinical entity with only one case in literature reported in 1953. Women with NF1 are at risk of developing breast cancer and men also may be at risk but there is scarce data on the risk and association of NF1 with male breast cancer due to its rarity. Established clinical trials in male breast cancer patients are lacking and the results are extrapolated from female breast cancer patients. The treatment of male breast cancer is followed as per the guidelines of premenopausal female breast cancer and tamoxifen is the hormone treatment in them. Mendes et al suggests that silencing of NF1 gene confers resistance to tamoxifen. Our conclusions are that since NF1 is mutated or deleted in one third of sporadic breast cancers, its role as a molecular driver for treatment has to be further explored.     

In vitro antitumor evaluation of 4H-chromene-3-carbonitrile derivatives as a new series of apoptotic inducers

Apoptosis is a naturally occurring process by which a cell is directed to programmed cell death. Chemotherapy drugs affect the cancer cells by the apoptotic induction. During the present study, a series of 4H-chromene-3-carbonitrile was synthesized by one-pot method as the inducers of apoptosis. Cytotoxic effects of six compounds of 4H-chromene-3-carbonitrile were evaluated against five tumor cell lines, with the help of colorimetric 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl tetrazolium bromide (MTT) assay. Compound 4 showed significant cytotoxic activity and was selected for conjugation with the synthesized gold nanoparticles by aspartic acid. Also, we evaluated apoptosis induction capacity of the selected compound with the help of fluorescent dyes and DNA fragmentation. The result showed that the conjugated and non-conjugated forms of compound 4 were effective in inducing apoptosis and conjugated one had more efficiency and reduced the effective dose. Also, molecular modeling experiments involving compound 4 and colchicine binding site of tubulin dimer showed several strong hydrogen bonds and hydrophobic interactions to many important amino acid residues and GTP.     

Molecular evidence for polyphyletic origin of human immunodeficiency virus type 1 subtype C in Bangladesh

HIV-1 positive blood samples were collected between 1999 and 2005 from population groups most at risk of HIV infection in Bangladesh through the national surveillance, from clients of the Voluntary Counseling and Testing (VCT) Unit for HIV at ICDDR,B and a survey of HIV in patients with tuberculosis. Partial sequences of the gag gene were used for subtyping the HIV strains by nested PCR using selective primers. Of the 198 HIV strains tested, subtype C (41.4%) was the commonest strain identified. Phylogenetic analysis of Bangladeshi subtype C strains showed that they clustered in polyphyletic branches representing HIV strains from different parts of the world. Most of the strains from injecting drug users (IDU) clustered together and were similar to Indian strains. The VCT strains however were very heterogeneous and clustered with strains from India, Myanmar, Ethiopia and Zimbabwe. Data suggest that there have been few introductions into the IDU population where the epidemic is driven by indigenous transmission. On the other hand there have been many and regular introductions of subtype C viruses through migrant workers in the VCT group. Very little overlap was observed in the strains obtained from IDU and those from other population groups.     

Effects of bone morphogenetic proteins on primary human renal cells and the generation of bone morphogenetic protein-7-expressing cells for application in bioartificial kidneys

Bioartificial kidneys (BAKs) contain renal cells, and primary human renal proximal tubule cells (HPTCs) have been applied in clinical trials with BAKs. Cell performance within the device is critical. HPTC performance is often compromised under in vitro conditions because of dedifferentiation, transdifferentiation, and tubule formation on substrate surfaces. Herein we tested whether treatments with human recombinant bone morphogenetic protein (BMP)-2 or BMP-7 would improve HPTC performance. We found that both growth factors improved HPTC performance, but more consistent results were obtained with BMP-7. The effects were strongly concentration dependent, and for BMP-7, 25?ng/mL was the optimal concentration, which improved HPTC performance under static and under bioreactor conditions. As an alternative to supplementation with the purified growth factor, we generated HPTCs secreting human recombinant BMP-7. BMP-7 secreted by the cells was bioactive and improved the functional performance of HPTCs, in agreement with our other findings. Together, the results suggested that either supplementation with purified BMP-7 or BMP-7-producing cells could be used to improve cell performance in BAKs. BAKs with BMP-7-producing cells could also be used to deliver the growth factor to kidney patients. Our results suggested that the amount of BMP-7 produced by HPTCs would be sufficient for therapeutic applications.     

Temporal PCB and mercury trends in Lake Erie fish communities: a dynamic linear modeling analysis

We performed dynamic linear modeling analysis on fish contaminant data collected from the Ontario Ministry of the Environment and Environment Canada to examine long-term trends of total mercury (THg) and polychlorinated biphenyls (PCBs) in Lake Erie. Several sport fish species (walleye, smallmouth bass, rainbow trout) with differences in their diet habits, food competition strategies and foraging patterns are characterized by weakly increasing trends of their THg levels in Lake Erie after the mid- or late 1990s. Similarly, our analysis shows that the decline rates of the PCB body burdens in white bass, smallmouth bass, freshwater drum and whitefish have slowed down or have switched to weakly increasing rates over the last decade. Our analysis also provides evidence that the rainbow trout and coho salmon PCB concentrations have been decreasing steadily but the associated rates were fairly weak. The systematic shifts in energy trophodynamics along with the food web alterations induced from the introduction of non-native species, the new role of the sediments as a net contaminant source, and the potentially significant fluxes from the atmosphere stand out as some of the hypotheses proposed to explain the limited Lake Erie response in recent years to the various contamination mitigation strategies.     

Clinical manifestations of co-infection with malaria and leptospirosis

Though both malaria and leptospirosis are frequent in the tropics, co-infections are under-recognized due to overlapping of clinical features. Here, we reviewed clinical manifestations of published co-infection along with our three cases. Out of a total of 18 patients, nine patients (50%) required ICU admission. Almost all patients had prodromal symptoms in the form of fever, headache and myalgia. Seven patients (37%) had altered sensorium, three patients (17%) had hypotension at admission, and 11 patients (61%) had acute kidney injury (AKI). Pulmonary manifestations in the form of pulmonary bleeding were present in four cases (22%). Three (17%) patients had acute lung injury/ acute respiratory distress syndrome. Almost 55% patients had DIC in the form of altered prothrombin time, activated partial thromboplastin time and low fibrinogen level. Four patients (22%) had subconjuctival suffusion, two of them had haematuria, while one presented with nasal bleeding. All patients had altered liver function tests. Of all the 18 patients, 17 (94%) survived, while one died.     

The role of DTI in early detection of cervical spondylotic myelopathy: a preliminary study with 3-T MRI

Introduction  

The radiological diagnosis of cervical spondylotic myelopathy (CSM) has to be made as soon as possible, since surgery performed in earlier stages during the course of CSM was reported to be more successful when compared with later stages. We hypothesized that diffusion tensor imaging (DTI) may detect CSM in earlier stages, before the appearance of signal increase in T2-weighted sequences.