Effects of high-fat diet withdrawal on behavior and striatal opioid gene expression [abstract]

Abstract only availableFaculty Mentor: Dr. Matthew Will, Psychological SciencesThe central opioid systems play a critical role in certain aspects of food intake, particularly with regard to the rewarding impact of calorically dense food such as fat and sugar. The striatal opioid enkephalin may be a key component of this system. Infusions of mu opiate agonists into this region greatly increase feeding, while infusions of opiate antagonists decrease food intake. Only recently has enkephalin gene expression in relation to differing motivational states been explored. Recent evidence suggests that expression of striatal preproenkephalin mRNA responds to short-term food motivational states, but not to long-term metabolic responses such as diet restriction. The following study will expand on this and other findings by examining preproenkephalin expression patterns during another important motivational state: withdrawal from a high-fat diet. While it has previously been shown that preproenkephalin expression down regulates following intermittent exposure to a chronic high-fat liquid, the current study will examine the influence of withdrawal from a high-fat diet on preproenkephalin expression, while assessing the motivational state of the subject immediately prior to sacrifice. Rats will be placed in automated behavioral testing chambers and given 2.5 hr limited access to either a high-fat diet or chow for 14 consecutive days. On the 15th day, all rats will again be placed in the same chambers, yet half of the rats from each group will receive their respective diet, while the other half will receive no food (withdrawal state). During all days of the experiment, behavioral measures of both appetitive (approach and seeking), consummatory (amount eaten), and behavioral activity will be assessed. At the end of the 2.5 hr feeding session on the 15th day, all rats will be sacrificed and their brains will be prepared for analysis of preproenkephalin expression in the striatum and other feeding related regions

Novel inhibition mechanism and potent antiviral activity of translocation-deficient reverse transcriptase inhibitors [abstract]

Abstract only availableNucleoside RT inhibitors (NRTIs) are among the most potent anti-HIV agents and act as chain terminators because they lack a 3'OH. However, this feature can reduce affinity for RT compared to the analogous dNTP substrate, as well as reduced intracellular conversion to the active dNTP. To overcome this, it was shown that certain nucleosides that retain the 3'OH and have substitutions at the 4' ribose and 2 position of the base have exceptional antiviral properties. One of these compounds, 4'-ethynyl, 2-fluoro deoxy-adenosine (4'E-2FdA) is the most potent NRTI inhibitor against wild-type and multi-drug resistant HIV viruses described to date. We have recently reported that 4'E-2FdA acts as a chain terminator despite the presence of an accessible 3'OH. We show that after 4'E-2FdA-MP incorporation, RT does not bind the next incoming dNTP. We analyzed RT translocation on different sequences terminated with 4'E-2FdA-MP, and found that even at sequences when RT is naturally found post-translocated, the inhibitor prevents translocation. This decrease in translocation efficiency explains the reduced binding of the next incoming dNTP and the termination of elongation. While the inhibitor stabilizes the pre-translocated 4'E-2FdA-MP-terminated primer, the pyrophosphate-dependent excision rate of 4'E-2FdA-MP was not very high compared to ddAMP. In conclusion, this highly potent chain termination activity arises from difficulty of the primer 3'-terminus to translocate following incorporation of the compound, and not from simple steric hindrance due to the 4' substitution. Therefore, we propose that 4'E-2FdA is a Translocation-Deficient Reverse Transcriptase Inhibitor (TDRTI) that acts by a novel mechanism.NIH grant to S. Sarafiano

Investigation of an extensive outbreak of HIV infection among children in Sindh, Pakistan: protocol for a matched case-control study.

INTRODUCTION: In April 2019, 14 children were diagnosed with HIV infection by a private healthcare provider in Larkana district, Sindh province, Pakistan. Over the next 3 months, 930 individuals were diagnosed with HIV, >80% below 16 years, the largest ever outbreak of HIV in children in Pakistan. In this protocol paper, we describe research methods for assessing likely modes of HIV transmission in this outbreak and investigate spatial and molecular epidemiology. METHODS AND ANALYSIS: A matched case-control study will be conducted with 406 cases recruited. Cases will be children aged below 16 years registered for care at the HIV treatment centre at Shaikh Zayed Children Hospital in Larkana City. Controls will be children who are HIV-uninfected (confirmed by a rapid HIV test) matched 1:1 by age (within 1 year), sex and neighbourhood. Following written informed consent from the guardian, a structured questionnaire will be administered to collect data on sociodemographic indices and exposure to risk factors for parenteral, vertical and sexual (only among those aged above 10 years) HIV transmission. A blood sample will be collected for hepatitis B and C serology (cases and controls) and HIV lineage studies (cases only). Mothers of participants will be tested for HIV to investigate the possibility of mother-to-child transmission. Conditional logistic regression will be used to investigate the association of a priori defined risk factors with HIV infection. Phylogenetic analyses will be conducted. Global positioning system coordinates of participants' addresses will be collected to investigate concordance between the genetic and spatial epidemiology. ETHICS AND DISSEMINATION: Ethical approval was granted by the Ethics Review Committee of the Aga Khan University, Karachi. Study results will be shared with Sindh and National AIDS Control Programs, relevant governmental and non-governmental organisations, presented at national and international research conferences and published in international peer-reviewed scientific journals

Limiting Dietary Sugar Improves Pediatric Sinonasal Symptoms And Reduces Inflammation

Excessive sugar consumption is associated with many chronic inflammatory diseases in adults. The effects of excessive sugar consumption in children have not been determined. In this study, we hypothesized that sinonasal symptoms and proinflammatory cytokine levels would be related and could be altered through reduction in sugar-sweetened beverage (SSB) consumption. To test this, we conducted a pilot study involving behavior modification and a 2-week follow-up. Seventeen children participants were recruited, and eleven completed the study. The experimental group presented with chronic nasal congestion or rhinorrhea defined by daily symptoms without acute illness for at least 3 months. The control group presented for non-nasal problems. Both groups received counseling to decrease SSB consumption. The Sinus and Nasal Quality of Life (SN-5) Survey was administered, and a blood sample was obtained by venipuncture at baseline and 2 weeks after counseling. Participants kept a 2-week food diary to document sugar intake. Serum lipid profile and inflammatory cytokines were measured. The experimental group reduced daily sugar intake, 46% versus 11% in the control. Baseline SN-5 scores were significantly worse in the experimental group and normalized to controls after intervention. Inflammatory cytokine levels were not different at baseline, but the experimental group significantly reduced in proinflammatory markers and increased the levels of anti-inflammatory markers after intervention. Our pilot data demonstrate higher sugar consumption may be associated with increased inflammatory stress and sinonasal symptoms. Reducing SSB and controlling inflammation in early childhood may have future health benefits