A stapled POL κ peptide targets REV1 to inhibit mutagenic translesion synthesis

Stapled α-helical RIR (Rev1-interacting region) peptides of DNA POL κ bind more effectively to the RIR-interface of the C-terminal recruitment domain of the translesion synthesis DNA polymerase Rev1 than unstapled peptide. The tightest-binding stapled peptide translocates into cells and enhances the cytotoxicity of DNA damaging agents while reducing mutagenesis. Drugs with these characteristics could potentially serve as adjuvants to improve chemotherapy and reduce acquired resistance by inhibiting Rev1-dependent mutagenic translesion synthesis.     

The first INFORMAS national food environments and policies survey in New Zealand: A blueprint country profile for measuring progress on creating healthy food environments

The International Network for Food and Obesity/NCDs Research, Monitoring and Action Support aims to benchmark national food environments. This study proposes a blueprint country profile to measure progress on creating healthy food environments, based on the results of the first, comprehensive survey in New Zealand (NZ). We assessed the implementation of national food environment policies and food industry commitments to improve population nutrition and the strength and comprehensiveness of public sector settings' nutrition policies. The healthiness of the packaged food supply, including health‐related labelling, was evaluated. Food environments were measured in 833 schools, 204 supermarkets, 1500 takeaway outlets, 28 hospitals, 70 sport centres, and around all NZ schools. Food swamps, defined as areas with high relative density of unhealthy food outlets, were identified, and food marketing to children on television, websites, social media and packages, in magazines, and in and around schools was measured. The cost differential between healthy and current household diets was calculated for different population groups. NZ's food environment profile is largely unhealthy, and there are inequalities in access to healthy food environments. It is anticipated that the proposed country profile can help other countries tackle unhealthy food environments through increasing accountability of governments and the industry.     

Algorithmic approach to diagnosis and management of post-refractive surgery dry eye disease

Dry eye disease (DED) is a condition that is fast reaching epidemic proportions around the world. Dry eye post-refractive surgery is the leading cause of iatrogenically induced DED. The wide variety of presentations and the disparity between signs and symptoms in many patients make this a very challenging aspect of our clinical practice. There has been a paradigm shift in the way we approach and treat this condition. The International Dry eye workshop has added new knowledge and focus to our management of dry eye. A wide range of newer diagnostic modalities are available for the diagnosis of DED. Dry eye is one of the most common side effects of refractive surgery and can have a bearing the patient''s perception of surgical outcomes as well. A thorough understanding of the possible underlying etiopathologies of this disease and the difference in etiopathogenesis of postrefractive dry eye is essential for optimal outcomes. It is important to approach each case in a unique fashion and customize the therapy to the patient presentation. This review article compiles all these aspects of management of dry eye in general, and postrefractive surgery dry eye in particular; from the ones commonly practiced in the clinic to the newer modalities of therapy with insights into the disease from a more practical point of view.     

Hemorrhagic Skin Nodules and Plaques: A Diagnostic Clue to Underlying Primary Plasma Cell Leukemia

Plasma cell leukemia (PCL) is a rare lymphoproliferative disorder characterized by a malignant proliferation of plasma cells (PC) in blood and marrow. Cutaneous involvement is very rare in PCL. We present the case of a 45-year-old lady who presented with multiple hemorrhagic nodules and plaques in the skin. Her total leucocyte count was 2,00,200/cmm with 85% abnormal plasmacytoid cells in peripheral smear. Biopsy of the skin lesions revealed diffuse infiltration by plasma cells with ‘choked’ blood vessels. A diagnosis of plasma cell leukemia with cutaneous involvement was made. On the second day of admission, the patient expired probably because of intracranial bleed due to thrombocytopenia. Post-mortem bone marrow and liver biopsy also showed diffuse infiltration by plasma cells. Monoclonality of the cells was proven by demonstrating the production of only kappa light chains.     

Nuclear DNA fragmentation during postnatal tooth development of mouse and hamster and during dentin repair in the rat

The TUNEL (transferase-mediated. dUTP-biotin nick end labeling) method for in situ labeling of DNA strands was utilized to localize DNA fragmentation in cells involved in tooth formation in the neonatal mouse and hamster. Positive reactions for the presence of DNA fragments were obtained in some epithelial cells of the cervical loop region of incisors, late secretory, transitional and early maturation stage ameloblasts, stratum intermedium cells and in shortened ameloblasts just before eruption. Also, cells of the periodontal ligament of the continuously erupting incisors stained positive shortly before eruption. Odontoblasts were negative but became strongly positive during the formation of physiological osteodentin at the tip of developing incisors. Osteodentin matrix and the surfaces of unerupted enamel and cementum just prior to eruption stained for DNA fragments as well. DNA fragmentation could be elicited in odontoblasts and underlying pulpal tissues of mature erupted molars after mechanical injury to the odontoblast processes during cavity preparation. We conclude that, in rodents. DNA fragmentation and cell death are biological processes which take place in a variety of cells involved in formation of teeth. The TUNEL staining technique is a simple but powerful tool to examine the fate of cells and tissues undergoing either programmed cell death (apoptosis) or fragmentation of nuclear DNA induced by external factors leading to pathological changes.     

Multiple Sclerosis: Fas Signaling in Oligodendrocyte Cell Death

Fas is a cell surface receptor that transduces cell death signals when cross-linked by agonist antibodies or by fas ligand. In this study, we examined the potential of fas to contribute to oligodendrocyte (OL) injury and demyelination as they occur in the human demyelinating disease multiple sclerosis (MS). Immunohistochemical study of central nervous system (CNS) tissue from MS subjects demonstrated elevated fas expression on OLs in chronic active and chronic silent MS lesions compared with OLs in control tissue from subjects with or without other neurologic diseases. In such lesions, microglia and infiltrating lymphocytes displayed intense immunoreactivity to fas ligand. In dissociated glial cell cultures prepared from human adult CNS tissue, fas expression was restricted to OLs. Fas ligation with the anti-fas monoclonal antibody M3 or with the fas–ligand induced rapid OL cell membrane lysis, assessed by LDH release and trypan blue uptake and subsequent cell death. In contrast to the activity of fas in other cellular systems, dying OLs did not exhibit evidence of apoptosis, assessed morphologically and by terminal transferase–mediated d-uridine triphosphate-biotin nick-end-labeling staining for DNA fragmentation. Other stimuli such as C2-ceramide were capable of inducing rapid apoptosis in OLs. Antibodies directed at other surface molecules expressed on OLs or the M33 nonactivating anti-fas monoclonal antibody did not induce cytolysis of OLs. Our results suggest that fas-mediated signaling might contribute in a novel cytolytic manner to immune-mediated OL injury in MS.     

A comparison of the colorectal surgical research across Europe, USA and Australasia

Aim The annual scientific meetings of the Association of Coloproctology of Great Britain and Ireland (ACPGBI), the American Society of Colon and Rectal Surgeons (ASCRS), the European Society of Coloproctology (ESCP) and the Royal Australasian College of Surgeons (RACS) are the major fora for presentation of colorectal surgical research. Thus, their content could be a proxy of the content and quality of colorectal surgical research worldwide. We aimed to critically appraise the quantity, quality and topics of colorectal surgical research over the previous 5 years for the above meetings. Method All published abstracts from the ACPGBI, ASCRS, ESCP and the colorectal‐specific component of the RACS from 2006 to 2010 were appraised. Abstracts were coded by predefined categories pertaining to study type and topic. Results Level 1 evidence (systematic reviews/meta‐analyses) and level 2 evidence (randomized controlled trials) comprised 3% (95% CI 1–9%) and 5% (95% CI 2–11%), respectively, of research presented at the meetings. There was a predominance of level 4 evidence (retrospective studies) across all years (mean 54%, 95% CI 44–68%). Operative management was most commonly studied (mean 43%, 95% CI 36–49%). There was minimal research in perioperative care (mean 6%, 95% CI 2–13%) and basic surgical science (mean 6%, 95% CI 2–11%). Research related to perioperative care was significantly higher at the ACPGBI and RACS meetings than the ASCRS and ESCP meetings (P < 0.01). Conclusion The research at these meetings consists largely of retrospective reviews exploring operative management with minimal high quality scientific content. Active steps need to be taken to increase the quantity of high level evidence especially in topics other than operative management.     

Neuroendocrine evidence that (S)-2-(chloro-5-fluoro-indol- l-yl)-1-methylethylamine fumarate (Ro 60-0175) is not a selective 5-hydroxytryptamine(2C) receptor agonist

The 5-hydroxytryptamine(2A) and (2C) (5-HT(2A) and 5-HT(2C)) receptors are so closely related that selective agonists have not been developed until recently with the advent of (S)-2-(chloro-5-fluoro-indol-l-yl)-1-methylethylamine fumarate (Ro 60-0175), a putatively selective 5-HT(2C) receptor agonist. In the present study, Ro 60-0175 was used to analyze the importance of 5-HT(2C) receptors in hormone secretion. Injection of Ro 60-0175 (5 mg/kg s.c.) produced a maximum increase in plasma levels of adrenocorticotrophic hormone, oxytocin, and prolactin at 15 min postinjection and a maximum increase in plasma corticosterone levels at 60 min postinjection. Ro 60-0175-mediated increases in plasma hormone levels were dose-dependent (corticosterone ED(50) = 2.43 mg/kg; oxytocin ED(50) = 4.19 mg/kg; and prolactin ED(50) = 4.03 mg/kg). To assess the role of 5-HT(2C) and 5-HT(2A) receptors in mediating the hormone responses to Ro 60-0175, rats were pretreated with the 5-HT(2C) antagonist 6-chloro-5-methyl-1-[2-(2-methylpyridyl-3-oxy)-pyrid-5-yl carbonyl] indoline (SB 242084) or 5-HT(2A) antagonists (+/-)-2,3-dimethoxyphenyl-1-[2-4-(piperidine)-methanol] (MDL 100,907) before injection of Ro 60-0175 (5 mg/kg s.c.). Neither SB 242084 (0.1, 0.5, 1, and 5 mg/kg i.p.) nor MDL 100,907 (1, 5, and 10 microg/kg s.c.) significantly inhibited the Ro 60-0175-induced increases in plasma hormone levels. The data suggest that Ro 60-0175 increases hormone secretion by mechanisms independent of the activation of 5-HT(2C) and/or 5-HT(2A) receptors and suggest that Ro 60-0175 is not a highly selective 5-HT(2C) receptor agonist.     

The use of gene clusters to infer functional coupling

Previously, we presented evidence that it is possible to predict functional coupling between genes based on conservation of gene clusters between genomes. With the rapid increase in the availability of prokaryotic sequence data, it has become possible to verify and apply the technique. In this paper, we extend our characterization of the parameters that determine the utility of the approach, and we generalize the approach in a way that supports detection of common classes of functionally coupled genes (e.g., transport and signal transduction clusters). Now that the analysis includes over 30 complete or nearly complete genomes, it has become clear that this approach will play a significant role in supporting efforts to assign functionality to the remaining uncharacterized genes in sequenced genomes.     

Role of GABA Deficit in Sensitivity to the Psychotomimetic Effects of Amphetamine

Some schizophrenia patients are more sensitive to amphetamine (AMPH)-induced exacerbations in psychosis–an effect that correlates with higher striatal dopamine release. This enhanced vulnerability may be related to gamma-aminobutyric acid (GABA) deficits observed in schizophrenia. We hypothesized that a pharmacologically induced GABA deficit would create vulnerability to the psychotomimetic effects to the ‘subthreshold'' dose of AMPH in healthy subjects, which by itself would not induce clinically significant increase in positive symptoms. To test this hypothesis, a GABA deficit was induced by intravenous infusion of iomazenil (IOM; 3.7 μg/kg), an antagonist and partial inverse agonist of benzodiazepine receptor. A subthreshold dose of AMPH (0.1 mg/kg) was administered by intravenous infusion. Healthy subjects received placebo IOM followed by placebo AMPH, active IOM followed by placebo AMPH, placebo IOM followed by active AMPH, and active IOM followed by active AMPH in a randomized, double-blind crossover design over 4 test days. Twelve healthy subjects who had a subclinical response to active AMPH alone were included in the analysis. Psychotomimetic effects (Positive and Negative Syndrome Scale (PANSS)), perceptual alterations (Clinician Administered Dissociative Symptoms Scale (CADSS)), and subjective effects (visual analog scale) were captured before and after the administration of drugs. IOM significantly augmented AMPH-induced peak changes in PANSS positive symptom subscale and both subjective and objective CADSS scores. There were no pharmacokinetic interactions. In conclusion, GABA deficits increased vulnerability to amphetamine-induced psychosis-relevant effects in healthy subjects, suggesting that pre-existing GABA deficits may explain why a subgroup of schizophrenia patients are vulnerable to AMPH.