Loss of metabolic plasticity underlies metformin toxicity in aged Caenorhabditis elegans.

Current clinical trials are testing the life-extending benefits of the diabetes drug metformin in healthy individuals without diabetes. However, the metabolic response of a non-diabetic cohort to metformin treatment has not been studied. Here, we show in C. elegans and human primary cells that metformin shortens lifespan when provided in late life, contrary to its positive effects in young organisms. We find that metformin exacerbates ageing-associated mitochondrial dysfunction, causing respiratory failure. Age-related failure to induce glycolysis and activate the dietary-restriction-like mobilization of lipid reserves in response to metformin result in lethal ATP exhaustion in metformin-treated aged worms and late-passage human cells, which can be rescued by ectopic stabilization of cellular ATP content. Metformin toxicity is alleviated in worms harbouring disruptions in insulin-receptor signalling, which show enhanced resilience to mitochondrial distortions at old age. Together, our data show that metformin induces deleterious changes of conserved metabolic pathways in late life, which could bring into question its benefits for older individuals without diabetes.

The effect of multiple autoclave cycles on the surface of rotary nickel-titanium endodontic files: An in vitro atomic force microscopy investigation.

AIMS: To observe and study the effect of multiple autoclave sterilization cycles, on the surface of nickel-titanium (NiTi) files. MATERIALS AND METHODS: The file used for this study was the Mtwo file (VDW) and ProTaper (Dentsply). The apical 5 mm of the files were attached to a silicon wafer and subjected to autoclave cycles under standardized conditions. They were scanned with an AFM after 1, 5, and 10 cycles. The unsterilized files were used as control, before start of the study. Three vertical topographic parameters namely maximum height (MH), root mean square (RMS) of surface roughness, and arithmetic mean roughness (AMR)were measured with the atomic force microscope (AFM). Analysis of variance along with Tukey's test was used to test the differences. RESULTS: The vertical topographic parameters were higher for both the files, right after the first cycle, when compared with the control (P < 0.01). The surface roughness increased sharply for Mtwo when compared to ProTaper, though ProTaper had a rougher surface initially. CONCLUSIONS: The study confirmed that the irregularities present on the surface of the file became more prominent with multiple autoclave cycles, a fact that should be kept in mind during their reuse.

A versatile approach for the site-specific modification of recombinant antibodies using a combination of enzyme-mediated bioconjugation and click chemistry.

A unique two-step modular system for site-specific antibody modification and conjugation is reported. The first step of this approach uses enzymatic bioconjugation with the transpeptidase Sortase A for incorporation of strained cyclooctyne functional groups. The second step of this modular approach involves the azide-alkyne cycloaddition click reaction. The versatility of the two-step approach has been exemplified by the selective incorporation of fluorescent dyes and a positron-emitting copper-64 radiotracer for fluorescence and positron-emission tomography imaging of activated platelets, platelet aggregates, and thrombi, respectively. This flexible and versatile approach could be readily adapted to incorporate a large array of tailor-made functional groups using reliable click chemistry whilst preserving the activity of the antibody or other sensitive biological macromolecules.

Mortality pattern of the 26/11 Mumbai terror attacks.

BACKGROUND: Mumbai, one of the industrial capitals cities of the world, has witnessed a series of terror attacks over the last two decades. The 2008 Mumbai terror attacks referred as "26/11" drew widespread global condemnation and killed 166 people, in addition to wounding more than 300 people. The mortality pattern and the pathophysiology of organ injuries are presented. The objective of this study was to determine the different patterns of injury in a terrorist attack of such magnitude and clinical implications in reducing mortality. METHODS: Data were collected from hospital records of 114 victims whose postmortems were conducted at the Sir JJ Group of Hospitals. The records were studied with respect to pattern and nature of injury. RESULTS: A total of 175 people were killed, 9 were terrorist with 166 victims. Of the 166 mortalities, postmortems were conducted on 114 predominately male victims ages 5 to 70 years old; 108 of these were dead on arrival. Sixty-eight people died from bullet injuries, 30 from blast injuries, and 10 had both bullet and blast injuries. Six were postoperative deaths (all bullet injuries), of which two were early postoperative deaths and four late postoperative deaths due to septicemia. CONCLUSION: There was multimodal pattern of injuries with predominance of bullet injuries sustained to vital organs. The hostage crisis resulted in varied and delayed evacuation times, which led to the death of nine victims with non-severe organ injuries. Delayed implementation of Prehospital Trauma Life Support due to the unsecured site and the hostage crisis can also be one of the causes. LEVEL OF EVIDENCE: V, epidemiological study.

Phosphorylated self-peptides alter human leukocyte antigen class I-restricted antigen presentation and generate tumor-specific epitopes.

Human leukocyte antigen (HLA) class I molecules present a variety of posttranslationally modified epitopes at the cell surface, although the consequences of such presentation remain largely unclear. Phosphorylation plays a critical cellular role, and deregulation in phosphate metabolism is associated with disease, including autoimmunity and tumor immunity. We have solved the high-resolution structures of 3 HLA A2-restricted phosphopeptides associated with tumor immunity and compared them with the structures of their nonphosphorylated counterparts. Phosphorylation of the epitope was observed to affect the structure and mobility of the bound epitope. In addition, the phosphoamino acid stabilized the HLA peptide complex in an epitope-specific manner and was observed to exhibit discrete flexibility within the antigen-binding cleft. Collectively, our data suggest that phosphorylation generates neoepitopes that represent demanding targets for T-cell receptor ligation. These findings provide insights into the mode of phosphopeptide presentation by HLA as well as providing a platform for the rational design of a generation of posttranslationally modified tumor vaccines.