Screening and evaluation of thiourea derivatives for their HIV capsid and human cyclophilin A inhibitory activity

New anti-HIV-1 drugs that target different viral proteins or genes at various steps in the viral life cycle are highly expected. HIV-1 assembly and disassembly (uncoating) processes are critical for the HIV-1 replication. HIV-1 capsid (CA) and human cyclophilin A (CypA) play essential roles in these processes. Using an in vitro screening system, we evaluated 52 thiourea derivatives for their potential CA and CypA-inhibiting activities. The antiviral activity of these compounds is correlated with their CA assembly inhibitory ability and with their anti-PPIase activity, suggesting that these compounds could block HIV-1 replication by disrupting CA assembly and inhibiting the PPIase activity of CypA to interfere with capsid disassembly. Among them, three compounds D4, D5, and D6 displayed the most promising potency with CA-assembly rate 15.78, 18.42, and 7.97(×10⁻⁵) OD/s, and their IC₅₀ for inhibition of PPIase activity 0.45, 0.65, and 0.33 μM, respectively. The potent protein inhibitory activity resulted in their very low EC₅₀ values (≤1.00 μM). They can be used for rational design of novel anti-HIV-1 drugs.     

Apigenin prevents development of medroxyprogesterone acetate-accelerated 7,12-dimethylbenz(a)anthracene-induced mammary tumors in Sprague-Dawley rats

The use of progestins as a component of hormone replacement therapy has been linked to an increase in breast cancer risk in postmenopausal women. We have previously shown that medroxyprogesterone acetate (MPA), a commonly administered synthetic progestin, increases production of the potent angiogenic factor vascular endothelial growth factor (VEGF) by tumor cells, leading to the development of new blood vessels and tumor growth. We sought to identify nontoxic chemicals that would inhibit progestin-induced tumorigenesis. We used a recently developed progestin-dependent mammary cancer model in which tumors are induced in Sprague-Dawley rats by 7,12-dimethylbenz(a)anthracene (DMBA) treatment. The flavonoid apigenin, which we previously found to inhibit progestin-dependent VEGF synthesis in human breast cancer cells in vitro, significantly delayed the development of, and decreased the incidence and multiplicity of, MPA-accelerated DMBA-induced mammary tumors in this animal model. Whereas apigenin decreased the occurrence of such tumors, it did not block MPA-induced intraductal and lobular epithelial cell hyperplasia in the mammary tissue. Apigenin blocked MPA-dependent increases in VEGF, and suppressed VEGF receptor-2 (VEGFR-2) but not VEGFR-1 in regions of hyperplasia. No differences were observed in estrogen or progesterone receptor (ER/PR) levels, or the number of estrogen receptor-positive cells, within the mammary gland of MPA-treated animals administered apigenin, MPA-treated animals, and placebo treated animals. However, the number of progesterone receptor-positive cells was reduced in animals treated with MPA or MPA and apigenin compared with those treated with placebo. These findings suggest that apigenin has important chemopreventive properties for those breast cancers that develop in response to progestins.     

Determinants of Overweight and Obesity in Affluent Adolescent in Surat City, South Gujarat region, India

Background:

Obesity is a major global burden. Low levels of physical activity, TV watching, and dietary pattern are modifiable risk factors for overweight and obesity in adolescent.

Objective:

The objective of this study was to determine risk factors for overweight and obesity among affluent adolescent, in Surat city in south Gujarat.

Design:

Cross sectional from July 2009 to April 2010.

Setting:

Two private schools with tuition fees more than Rs. 2000 per month, were selected randomly using a random table.

Participants:

The participants were adolescents, 12 to 15 years of age.

Data collection:

Pre-designed and pre-tested questionnaire was used to elicit the information about dietary history and physical activity.

Measurement:

Height and weight was measured and BMI was calculated. Overweight and obesity were assessed by BMI for age. Student who had BMI for age <85^th and <95^th percentile of reference population were classified as overweight and BMI for age <95^th percentile of reference population were classified as obese (IAP Growth Monitoring Guidelines for Children from Birth to 18 Year).

Result:

The overall prevalence of obesity and overweight was 6.55% and 13.9% (boys: 6.7% and 15.1%; girls 6.4% and 13.35%). Final model of multiple logistic regression analysis showed that important determinants of overweight and obesity were low levels of physical activity, watching television or playing computer games, and consuming junk foods, snacks and carbonated drinks.

Conclusion:

The magnitude of obesity and overweight among affluent adolescent of Surat city was found to be 6.55% and 13.9%, respectively. Low level of physical activity, watching TV or playing computer games, and dietary pattern predisposed the adolescent to overweight/obesity.     

Genetic variation of the α2b-adrenoceptor affects neural correlates of successful emotional memory formation

Objective: Enhanced memory for emotionally charged events helps us to remember potentially vital information. There are large interindividual differences in emotional‐memory enhancement, but little is known about their neurobiological basis. Recently, a functional deletion variant of the gene that codes for the α2b‐adrenoceptor (ADRA2B) has been shown to affect memory for emotional experiences. Initial neuroimaging evidence linked this behavioral effect to increased amygdala activity, but its influence on successful memory processing remains unknown. Therefore, the aim of this study was to investigate the effect of the common deletion in the ADRA2B gene on neural activity related to specific mnemonic processing, successful memory formation, and retrieval. Methods: Twenty‐three noncarriers (10 males) and 28 deletion carriers (13 males) with a mean age of 24 years were investigated while performing an emotional‐learning task with sad and happy scenes. Functional magnetic resonance imaging was acquired both during memory formation and retrieval. Results: Although there were no differences in memory performance between groups, the common deletion variant of ADRA2B was related to enhanced activity in the amygdala and inferior frontal gyrus during successful emotional memory formation, but not retrieval. Deletion carriers showed a larger differential response in these brain regions between later‐remembered and later‐forgotten stimuli than nondeletion carriers did. Conclusion: Our results demonstrate that the ADRA2B polymorphism influences emotional memory formation but not memory retrieval in the amygdala and left inferior frontal gyrus. Hum Brain Mapp, 2011. © 2011 Wiley Periodicals, Inc.     

Characterization of Immune Responses to Capsid Protein p24 of Human Immunodeficiency Virus Type 1 and Implications for Detection

To further refine our current nanoparticle-based HIV-1 p24 antigen assay, we investigated immune responses to p24 to identify diagnostically significant immune dominant epitopes (IDEs) in HIV-infected human sera, to address cross-reactivity of anti-p24 antibodies to different subtypes, and to identify new biomarkers that distinguish acute from chronic HIV infection for more accurate incidence estimation. We identified two major linear epitope regions, located in the CypA binding loop and adjacent helices and at the end of the C-terminal domain. Most sera (86%) from acutely HIV-1-infected individuals reacted with multiple peptides, while 60% and 30% of AIDS patient samples reacted with multiple and single peptides, respectively. In contrast, 46% and 43% of chronically HIV-1-infected individuals reacted with one and none of the peptides, respectively, and only 11% reacted with multiple p24 peptides, indicating a progression of immune responses from polyclone-like during acute infection to monoclone-like or a nonresponse to linear epitopes during chronic infection. Anti-p24 antibodies (subtype B) show broad cross-reactivity to different HIV-1 subtypes, and the synergistic action of different combinations of anti-HIV antibodies improves capture and detection of divergent HIV-1 subtypes. Our results indicate that the modified peptide immunoassay is sensitive and specific for the rapid identification of HIV-1 p24 IDEs and for investigation of immune responses to p24 during natural HIV-1 infection. The data provide the foundation for development and refinement of new assays for improved p24 antigen testing as future tools for rapid and accurate diagnosis as part of early intervention strategies and estimations of incidence.Capsid protein (CA), or p24 antigen, of human immunodeficiency virus type 1 (HIV-1) is the most abundant viral protein, since each virus contains about 1,500 to 3,000 p24 molecules (30, 37). During early and late stages of HIV infection, it is always present at relatively high levels in the blood, making it a potential viral marker for diagnosis, blood donor screening, monitoring disease progression, and evaluating antiretroviral therapy (1, 5, 6, 25). However, conventional enzyme-linked immunosorbent assays (ELISAs) for HIV-1 p24 detection have relatively low sensitivity and have been replaced by nucleic acid testing (NAT) in the United States (29). Over the past decade, the performance of p24 assays has been improved significantly by implementing immune complex disruption methods (23, 26), using more effective lysis buffers (27), and incorporating tyramide-mediated signal amplification (TSA) (4). We showed that by using gold nanoparticles (NPs), the detection limit for p24 antigen could be reduced to 0.1 pg/ml (35) and the window period (the time between HIV exposure and detection of antibody seroconversion) could be shortened by at least 3 days (35). Antigen assays could also be useful for HIV diagnostics in pediatrics and for testing the blood supply in resource-limited settings where NAT is not available or practical. By using nanotechnology and nanoparticles, the sensitivity of the immunoassay could be improved while making it less expensive and simpler than current ELISA methods (32, 33, 35). However, assay accuracy depends on the quality of anti-p24 antibodies and their immune response to p24 antigen. To refine and develop a more sensitive HIV-1 p24 antigen assay, further study of immune responses to p24 antigen to identify the immune dominant epitopes (IDEs) in HIV-infected human sera is necessary, since B-cell epitopes of p24 that have been identified are based mainly on the characterization of immune responses to murine monoclonal anti-p24 antibodies (Los Alamos HIV Molecular Immunology Database [http://www.hiv.lanl.gov/content/immunology/maps/ab/p24.html]). Such studies are limited and show controversial results (9, 13, 15, 18).The second issue to be addressed with p24 antigen testing is the cross-reactivity of anti-p24 antibodies with different viral subtypes due to the broad genetic diversity of HIV-1 (21, 24). Cross-reactivity has been evaluated with several commercially available HIV-1 assays (14, 19), but detailed information on the anti-p24 antibodies used was not provided. Finally, there is a need to identify new biomarkers for acute HIV infection to more accurately estimate incidence rates in order to monitor the utility of prevention measures. Several unique epitopes of HIV-1 p24 antigen have been found to be immunodominant and may be recognized early in the course of natural infection or associated with disease progression (12, 13). These results indicate that assays utilizing specific epitopes of p24 and anti-p24 antibodies may help in the diagnosis of recent or acute HIV infection.Here we describe the characterization of major IDEs of HIV-1 p24, studies to evaluate the immune response profile during acute and chronic HIV-1 infection, and the cross-reactivities of monoclonal anti-p24 antibodies among different subtypes, as determined using a rapid, sensitive, NP-based immunoassay. The implications for p24 detection and assay development are also discussed.     

Primary hepatic carcinoid tumor in children

Primary carcinoid tumors of the liver are rare, with fewer than 60 cases currently reported in the English literature. We present the evaluation and management of a solid hepatic tumor in a 14-year-old boy. Intraoperative biopsy was indeterminant for malignant potential, and the patient underwent complete resection by left hepatic lobectomy. Final histopathologic evaluation of the mass revealed a carcinoid tumor.Extensive endoscopic and radiologic workup revealed no other primary source. The patient recovered well from surgery and is currently free of disease 32 months after initial resection. Review of the literature suggests that primary hepatic carcinoid tumors are particularly rare in children. As the liver is frequently a site for carcinoid metastasis from the gastrointestinal tract, any patient with a suspected primary hepatic carcinoid tumor must undergo an extensive search for an extrahepatic primary site. These tumors are typically indolent but may metastasize. In addition, medical therapy is of limited benefit in reducing tumor bulk. The mainstay for treatment of primary hepatic carcinoid tumors is surgical resection, and these tumors carry a more favorable prognosis than other primary hepatic malignancies and metastatic carcinoid. Follow-up is long-term, as these tumors can recur many years after initial resection.