Ethical obligation and legal requirements: On informed consent practices in Bangladesh

Informed consent to medical intervention is fundamental in both ethics and law. But in practice it is often not taken seriously in developing countries. This paper provides an appraisal of informed consent practices in Bangladesh. Following a review of the ethical and legal principles of informed consent, it assesses the degree to which doctors adhere to it in Bangladesh. Based on findings of non-compliance, it then investigates the reasons for such non-compliance through an appraisal of informed consent practices in Bangladesh and provides recommendations aimed at improving such practices. The significance of this paper lies in unveiling the interdependence between the ethical and legal traits of informed consent and their ramifications on strengthening the patient-oriented approach of duty to care.     

Characterization of intracellular viral RNA in interferon-treated cells chronically infected with murine leukemia virus.

We have recently found that Moloney murine leukemia virus assembles within cytoplasmic vacuoles of chronically infected NIH/3T3 cells rather than at their surface (submitted for publication). In the present study we found that if these cells were treated with interferon (IF) for 24 to 48 h the intracellular virus particles accumulated at a two- to threefold-higher level than that observed in untreated cells. Nevertheless, despite this accumulation, no difference between IF-treated and untreated cells was observed in the amount of the total cytoplasmic viral RNA or in its 35S or 21S species. When cellular virions were sedimented from the cytoplasmic fraction, a markedly higher amount of viral RNA was detected in the viral pellet of IF-treated cells than was detected in untreated cells, whereas the amount of viral RNA left in the virus-free cytoplasm of IF-treated cells was much lower than that in the untreated cells. Furthermore, the amount of the cytoplasmic polyriboadenylic acid-containing viral RNA was also remarkably higher in the IF-treated cells. Viral polyribosomes appeared to be fully functional in IF-treated cells, since no effect of IF on viral protein synthesis could be detected. Analysis of the nuclear viral RNA showed no difference between IF-treated and untreated cells after 24 h of IF treatment. Both contained a comparable amount of 35S viral RNA. However, at 48 h a significant accumulation of viral RNA was observed in the nucleus of the IF-treated cells as compared with the untreated cells, although in both cases only 35S species were evident. This accumulation appeared to activate a degradation process which destroyed nuclear viral RNA, since a dramatic shift toward smaller-sized molecules of viral RNA and a remarkable reduction in its amount were observed after 72 h of IF treatment.     

Limited dispersal and an unexpected aggression pattern in a native supercolonial ant

Understanding how social groups function requires studies on how individuals move across the landscape and interact with each other. Ant supercolonies are extreme cooperative units that may consist of thousands of interconnected nests, and their individuals cooperate over large spatial scales. However, the inner structure of suggested supercolonial (or unicolonial) societies has rarely been extensively studied using both genetic and behavioral analyses. We describe a dense supercolony‐like aggregation of more than 1,300 nests of the ant Formica (Coptoformica) pressilabris. We performed aggression assays and found that, while aggression levels were generally low, there was some aggression within the assumed supercolony. The occurrence of aggression increased with distance from the focal nest, in accordance with the genetically viscous population structure we observe by using 10 DNA microsatellite markers. However, the aggressive interactions do not follow any clear pattern that would allow specifying colony borders within the area. The genetic data indicate limited gene flow within and away from the supercolony. Our results show that a Formica supercolony is not necessarily a single unit but can be a more fluid mosaic of aggressive and amicable interactions instead, highlighting the need to study internest interactions in detail when describing supercolonies.     

Multiple genetic pathways regulate replicative senescence in telomerase‐deficient yeast

Most human tissues express low levels of telomerase and undergo telomere shortening and eventual senescence; the resulting limitation on tissue renewal can lead to a wide range of age‐dependent pathophysiologies. Increasing evidence indicates that the decline in cell division capacity in cells that lack telomerase can be influenced by numerous genetic factors. Here, we use telomerase‐defective strains of budding yeast to probe whether replicative senescence can be attenuated or accelerated by defects in factors previously implicated in handling of DNA termini. We show that the MRX (Mre11‐Rad50‐Xrs2) complex, as well as negative (Rif2) and positive (Tel1) regulators of this complex, comprise a single pathway that promotes replicative senescence, in a manner that recapitulates how these proteins modulate resection of DNA ends. In contrast, the Rad51 recombinase, which acts downstream of the MRX complex in double‐strand break (DSB) repair, regulates replicative senescence through a separate pathway operating in opposition to the MRX‐Tel1‐Rif2 pathway. Moreover, defects in several additional proteins implicated in DSB repair (Rif1 and Sae2) confer only transient effects during early or late stages of replicative senescence, respectively, further suggesting that a simple analogy between DSBs and eroding telomeres is incomplete. These results indicate that the replicative capacity of telomerase‐defective yeast is controlled by a network comprised of multiple pathways. It is likely that telomere shortening in telomerase‐depleted human cells is similarly under a complex pattern of genetic control; mechanistic understanding of this process should provide crucial information regarding how human tissues age in response to telomere erosion.     

Removal of a C-terminal serine residue proximal to the inter-chain disulfide bond of a human IgG1 lambda light chain mediates enhanced antibody stability and antibody dependent cell-mediated cytotoxicity

Optimization of biophysical properties is a critical success factor for the developability of monoclonal antibodies with potential therapeutic applications. The inter-domain disulfide bond between light chain (Lc) and heavy chain (Hc) in human IgG1 lends structural support for antibody scaffold stability, optimal antigen binding, and normal Fc function. Recently, human IgG1λ has been suggested to exhibit significantly greater susceptibility to reduction of the inter Lc-Hc disulfide bond relative to the same disulfide bond in human IgG1κ. To understand the molecular basis for this observed difference in stability, the sequence and structure of human IgG1λ and human IgG1κ were compared. Based on this Lc comparison, three single mutations were made in the λ Lc proximal to the cysteine residue, which forms a disulfide bond with the Hc. We determined that deletion of S214 (dS) improved resistance of the association between Lc and Hc to thermal stress. In addition, deletion of this terminal serine from the Lc of IgG1λ provided further benefit, including an increase in stability at elevated pH, increased yield from transient transfection, and improved in vitro antibody dependent cell-mediated cytotoxicity (ADCC). These observations support the conclusion that the presence of the terminal serine of the λ Lc creates a weaker inter-chain disulfide bond between the Lc and Hc, leading to slightly reduced stability and a potential compromise in IgG1λ function. Our data from a human IgG1λ provide a basis for further investigation of the effects of deleting terminal serine from λLc on the stability and function of other human IgG1λ antibodies.