Proteomic characterization of HIV-modulated membrane receptors, kinases and signaling proteins involved in novel angiogenic pathways

Background  

Kaposi's sarcoma (KS), hemangioma, and other angioproliferative diseases are highly prevalent in HIV-infected individuals. While KS is etiologically linked to the human herpesvirus-8 (HHV8) infection, HIV-patients without HHV-8 and those infected with unrelated viruses also develop angiopathies. Further, HIV-Tat can activate protein-tyrosine-kinase (PTK-activity) of the vascular endothelial growth factor receptor involved in stimulating angiogenic processes. However, Tat by itself or HHV8-genes alone cannot induce angiogenesis in vivo unless specific proteins/enzymes are produced synchronously by different cell-types. We therefore tested a hypothesis that chronic HIV-replication in non-endothelial cells may produce novel factors that provoke angiogenic pathways.     

Melatonin protects against experimental reflux esophagitis

Abstract:  Reflux esophagitis (RE), a major gastrointestinal disorder results from excess exposure of the esophageal mucosa to acidic gastric juice or bile-containing duodenal contents refluxed via an incompetent lower esophageal sphincter. Recent studies implicated oxygen derived free radicals in RE induced esophageal mucosal damage resulting in mucosal inflammation. Thus, control over free radical generation and modulation of inflammatory responses might offer better therapeutic effects to counteract the severity of RE. In this context we investigated the effect of melatonin against experimental RE in rats. Melatonin pretreatment significantly reduced the haemorrhagic lesions and decreased esophageal lipid peroxidation aggravated by RE. Moreover, the depleted levels of superoxide dismutase and glutathione observed in RE were replenished by melatonin signifying its free radical scavenging properties and antioxidant effects resulting in the improvement of esophageal defense mechanism. Further melatonin repressed the upregulated levels of expression of proinflammatory cytokines like, TNF-α, IL-1β and IL-6 in RE. However, increased levels of the anti-inflammatory cytokine IL-10 remained unaltered after melatonin administration signifying its immunomodulatory effect through suppression of Th1-mediated immune responses. The involvement of receptor dependent actions of melatonin against RE were also investigated with MT2 receptor antagonist, luzindole (LUZ). LUZ failed to antagonize melatonin's protective effects against RE indicating that melatonin mediated these beneficial effects in a receptor-independent fashion. Thus, esophageal mucosal protection elicited by melatonin against experimental RE is not only dependent on its free radical scavenging activity but also mediated in part through its effect on the associated inflammatory events in a receptor-independent manner.     

Negative effect of DNA hypermethylation on the outcome of intensive chemotherapy in older patients with high-risk myelodysplastic syndromes and acute myeloid leukemia following myelodysplastic syndrome.

PURPOSE: Promoter hypermethylation of, for example, tumor-suppressor genes, is considered to be an important step in cancerogenesis and a negative risk factor for survival in patients with myelodysplastic syndromes (MDS); however, its role for response to therapy has not been determined. This study was designed to assess the effect of methylation status on the outcome of conventional induction chemotherapy. EXPERIMENTAL DESIGN: Sixty patients with high-risk MDS or acute myeloid leukemia following MDS were treated with standard doses of daunorubicin and 1-beta-d-arabinofuranosylcytosine. Standard prognostic variables and methylation status of the P15(ink4b) (P15), E-cadherin (CDH), and hypermethylated in cancer 1 (HIC) genes were analyzed before treatment. RESULTS: Forty percent of the patients achieved complete remission (CR). CR rate was lower in patients with high WBC counts (P = 0.03) and high CD34 expression on bone marrow cells (P = 0.02). Whereas P15 status alone was not significantly associated with CR rate (P = 0.25), no patient with hypermethylation of all three genes achieved CR (P = 0.03). Moreover, patients with CDH methylation showed a significantly lower CR rate (P = 0.008), and CDH methylation retained its prognostic value also in the multivariate analysis. Hypermethylation was associated with increased CD34 expression, but not with other known predictive factors for response, such as cytogenetic profile. CONCLUSIONS: We show for the first time a significant effect of methylation status on the outcome of conventional chemotherapy in high-risk MDS and acute myelogenous leukemia following MDS. Provided confirmed in an independent study, our results should be used as a basis for therapeutic decision-making in this patient group.     

Novel approaches on prodrug based drug design

Prodrug design is really not different from the general drug discovery process, in which a unique substance is observed to have desirable pharmacological effects, and studies of its properties lead to the design of better drugs. It is a very fruitful way of research, and its introduction in human therapy has given successful results in improving the clinical and therapeutic effectiveness of drugs suffering from some undesirable properties that otherwise hinder their clinical usefulness. The present article reviews various prodrugs and their applications and presents the developments in this field during the last few decades. This review also highlights developing strategies in targeted prodrug design, including antibody-directed enzyme prodrug therapy, gene-directed enzyme prodrug therapy and peptide transporter-associated prodrug therapy. An erratum to this article can be found at     

Induction of histone acetylation and inhibition of growth of mouse erythroleukemia cells by S-allylmercaptocysteine

Growth-inhibitory effects on DS19 mouse erythroleukemia cells were seen in the micromolar concentration range with allicin and S-allylmercaptocysteine and in the millimolar range with allyl butyrate, allyl phenyl sulfone, and S-allyl cysteine. Increased acetylation of histones was induced by incubation of cells with the allyl compounds at concentrations similar to those that resulted in the inhibition of cell proliferation. The induction of histone acetylation by S-allylmercaptocysteine was also observed in Caco-2 human colon cancer cells and T47D human breast cancer cells. In contrast to the effect on histone acetylation, there was a decrease in the incorporation of phosphate into histones when DS19 cells were incubated with 25 microM S-allylmercaptocysteine. Histone deacetylase activity was inhibited by allyl butyrate, but there was little or no effect with the allyl sulfur compounds examined in this study. A similar degree of downregulation of histone deacetylase and histone acetyltransferase was observed when DS19 cells were incubated with S-allylmercaptocysteine or allyl isothiocyanate. The induction of histone acetylation by S-allylmercaptocysteine was not blocked by a proteasome inhibitor. The mechanism by which S-allylmercaptocysteine induces histone acetylation remains to be characterized. It may be related in part to metabolism to allyl mercaptan, which is a more effective inhibitor of histone deacetylase.     

Comparative genetic patterns of glioblastoma multiforme: potential diagnostic tool for tumor classification

Cytogenetic and molecular genetic studies of glioblastoma multiforme (GBM) have shown that the most frequent alterations are gains of chromosome 7, losses of 9p loci and chromosome 10, and gene amplification, primarily of the epidermal growth factor receptor (EGFR) gene. Although this profile is potentially useful in distinguishing GBM from other tumor types, the techniques used tend to be labor intensive, and some can detect only gains or losses of genetic loci. Comparative genomic hybridization (CGH) is a powerful technique capable of identifying both gains and losses of DNA sequences. The present study compares the CGH evaluation of 22 GBM with classic cytogenetics, loss of heterozygosity by allelotyping, and gene amplification by Southern blot analysis to determine the reliability of CGH in the genetic characterization of GBM. The CGH and karyotypic data were consistent in showing gain of chromosome 7 accompanied by a loss of chromosome 10 as the most frequent abnormality, followed by a loss of 9p in 17 of 22 GBM cases. Loss of heterozygosity of chromosomes 10 (19/22) and 9p (9/22) loci confirmed the underrepresentation by CGH. Genomic amplifications were observed by CGH in 5 of the 10 cases where gene amplification was detected by Southern blot analysis. The data show that CGH is equally reliable, compared with the more established genetic methods, for recognizing the prominent genetic alterations associated with GBM and support its use as a plausible adjunct to glioma classification.     

Human bladder carcinoma: characterization of two new tumor cell lines and search for tumor viruses.

Two newly established human bladder carcinoma cell lines, designated HT-1197 and HT-1376, were characterized. Cells of both cultures exhibited fine structural microvilli and tonofibrils indicative of their epithelial origin. In addition, desmosomes were also present in HT-1197. Marker chromosomes present in HT-1197 and HT-1376 distinguished these from each other and from other known human tumor cell lines. Both cultures grew in soft agar, induced fibrinolytic activity, and were tumorigenic in mice and hamsters. No type C or other virus expression was detected in these cell lines nor in other human urothelial tumors tested.     

A 2-year follow-up of orphans' competence, socioemotional problems and post-traumatic stress symptoms in traditional foster care and orphanages in Iraqi Kurdistan

BACKGROUND: This paper aims to compare orphans' development in two different care systems. METHODS: Based on age, sex, psychological trauma scores, competence and psychological problem scores, two comparable samples were found representing orphans in the traditional foster care (n = 94) and the orphanages (n = 48) in a middle-large city in Iraqi Kurdistan. At an index interview, Child Behaviour Checklist (CBCL), Harvard-Uppsala Trauma Questionnaire for Children and Post-traumatic Stress Symptoms for Children (PTSS-C) were administered to the caregivers. After 1 year the CBCL, and after 2 years both the CBCL and the PTSS-C, were-re-administered, consecutively. RESULTS: Although both samples revealed significant decrease in the means of total competence and problem scores over time, the improvement in activity scale, externalizing problem scores and post-traumatic stress disorder-related symptoms proved to be more significant in the foster care than in the orphanages. While the activity scale improved in the foster care, the school competence deteriorated in both samples, particularly among the girls in the orphanages. The improvement of boys' activity scores in the foster care, and deterioration of girls' school competence in the orphanages were the most significant gender differences between samples over time. CONCLUSIONS: Even if the two orphan care systems showed more similarities than differences, the foster care revealed better outcomes over time. The results are discussed in relation to gender, age, socio-economic situation, cultural values and the characteristics of each care system.     

Native renal biopsies: complications and glomerular yield between radiologists and nephrologists

Kidney biopsies have been taken over by radiologists at many institutions. This tendency for radiology referral by nephrologists has two main drawbacks: 1) No follow-up care from the physician performing the procedure and 2) Loss of required procedure training for nephrology fellows. This study assesses for differences in glomerular yield and immediate procedure-related complications between radiology-performed (RP) and nephrology-performed (NP) percutaneous native kidney biopsies at our institution for an 11-month period. All biopsies were done with real time ultrasound guidance. Further analysis was done to look for any correlation between the number of needle insertions ("passes"), needle size and procedure-related complications (graded on a score from 0-4). A total of 37 native kidney biopsies were performed during the study period. Fourteen biopsies (38%) were performed by radiology while a nephrology fellow performed 23 biopsies (62%). The mean glomerular count for RP biopsies was 15+/-10 and for NP 16+/-11 (p=ns). The number of passes ranged from 1-5 in the RP group with a total of 33 passes in 14 patients (mean 2.36 passes/patient). Passes ranged from 1-6 in the NP group with 57 passes in 23 patients (mean 2.48 passes/patient). Mean complication scores were similar in both groups. However, severe complications (score 4) were significantly lower in nephrology fellow performed biopsies (p = 0.001). Despite similar pre-biopsy risk assessment and treatment protocols with real-time ultrasound guidance of all biopsies, these results show no statistically significant differences in glomerular yield or overall complication scores but did demonstrate a significantly higher rate of severe complications (score 4) in the RP performed biopsies. Nephrology fellows perform native kidney biopsies at a level equal to or superior to radiologists.