Function modification of SR-PSOX by point mutations of basic amino acids

Background  

Atherosclerosis (AS) is a common cardiovascular disease. Transformation of macrophages to form foam cells by internalizing modified low density-lipoprotein (LDL) via scavenger receptor (SR) is a key pathogenic process in the onset of AS. It has been demonstrated that SR-PSOX functions as either a scavenger receptor for uptake of atherogenic lipoproteins and bacteria or a membrane-anchored chemokine for adhesion of macrophages and T-cells to the endothelium. Therefore, SR-PSOX plays an important role in the development of AS. In this study the key basic amino acids in the chemokine domain of SR-PSOX have been identified for its functions.     

L-histidine inhibits production of lysophosphatidic acid by the tumor-associated cytokine,autotaxin

Background  

Autotaxin (ATX, NPP-2), originally purified as a potent tumor cell motility factor, is now known to be the long-sought plasma lysophospholipase D (LPLD). The integrity of the enzymatic active site, including three crucial histidine moieties, is required for motility stimulation, as well as LPLD and 5'nucleotide phosphodiesterase (PDE) activities. Except for relatively non-specific chelation agents, there are no known inhibitors of the ATX LPLD activity.     

The silent point mutations at the cleavage site of 2A/2B have no effect on the self-cleavage activity of 2A of foot-and-mouth disease virus

The 2A region of the foot-and-mouth disease virus (FMDV) polyprotein is 18 amino acids in length, and 2A self-cleavage site (2A/2B) contains a conserved amino acid motif G_2A/P_2B. To investigate the synonymous codon usage for Glycine at the 2A/2B cleavage site of FMDV, 66 2A/2B₁ nucleotide sequences were aligned and found that the synonymous codon usage of G_2A is conserved and GGG was the most frequently used. To examine the role of synonymous codons for G_2A in self-cleavage efficiency of 2A/2B, recombinant constructs which contains the chloramphenicol acetyltransferase protein (CAT) and enhanced green fluorescent protein (EGFP) linked by the FMDV 2A sequence with four synonymous codons for G_2A were produced. The activities of all the F2As based plasmids were determined in CHO cells. The results showed that the synonymous codon usage patterns for G_2A at the cleavage site (2A/2B) have no effect on the cleavage efficiency. This suggests that the synonymous codon usage of 2A peptide has no effect on the cleavage efficiency of FMDV 2A element.     

Evaluation of scientific activity from the view point of medical librarians

The authors try to sum up briefly the rather complex topic of scientometry, with special regards to medical science. They discuss the role of medical librarians in the preparation of an analysis on scientific publications of individuals and/or institutions, because these can be considered as a measure of the scientific output. In a separate part the authors give a critical review of the tools and methods of bibliometrics, delineate the main problems of them. They discuss the Hungarian practice of scientometry and present some examples. For comparison they describe some examples from abroad as well. As a conclusion, the authors emphasise the importance of the presence of Hungarian publications in international scientific periodicals, at the same time the necessity of objective home measuring of the scientific output as well.     

Novel conformationally restricted triazole derivatives with potent antifungal activity

In continuation of our work on azole antifungal agents, a series of new conformationally restricted triazole derivatives possessing benzylpiperidin-4-yl methyl amino side chains were designed and synthesized. All the new azoles showed moderate to excellent in vitro antifungal activity against most of the tested pathogenic fungi. Several compounds (such as 12e, 12f, 12h and 12n) showed higher antifungal activity against Candida albicans than fluconazole. Moreover, compounds 12g-i also showed good activity against Aspergillus fumigatus with their MIC80 on the level of 1 μg/mL. Flexible molecular docking was used to analyze the binding mode of the designed compounds. They interact with CACYP51 through hydrophobic and van der Waals interactions.     

Prevalence of pfcrt point mutations and level of chloroquine resistance in Plasmodium falciparum isolates from Africa.

The development in Plasmodium falciparum of the resistance to chloroquine (CQ) constitutes a public health priority, due to its direct influence in childhood mortality. The molecular basis for CQ resistance (CQR) is still unclear but, recently, a new relevant gene, named pfcrt, with several point mutations was identified in P. falciparum. Two mutations, K76T and A220S, have been considered crucial for CQR in further studies, making the pfcrt a good candidate as determinant for CQR in P. falciparum. To contribute to this topic, we have undertaken a molecular screening on 164 P. falciparum isolates from Africa: 120 isolates were Italian imported malaria cases, 27 and 17 isolates were from a school-children survey from Congo and Tanzania, respectively. In vitro tests (pLDH and WHO-Mark III tests) for CQ sensitivity have been also carried out on 28 plasmodial isolates and results compared to those obtained by molecular analysis in the same isolates. The SVIET pfcrt haplotype has been identified in the samples from Congo, and this is the first time that this haplotype is detected in Africa. Our results give further evidence to the reliability of the 76T (and the linked 74I-75E) pfcrt point mutation as molecular marker for CQR.     

Occupational cancer genetics: infrequent ras oncogenes point mutations in lung cancer samples from chromate workers.

BACKGROUND: Chromium carcinogenicity and mutagenicity are no longer disputed. However, although chromium has various genetic effects that induce cancer, its mechanism of inducing lung cancer in humans is still not fully understood. p53, a tumor suppressor gene, was found to be infrequently mutated in samples of lung cancer in workers with long occupational exposure to chromium, suggesting other cancer-related genes to be targeted in such tumors. METHODS: To assess the contribution of the ras oncogenes in the pathogenesis of chromate-related lung cancer, we studied point mutations at the critical positions of codons 12, 13, and 61 of the Ha-ras and Ki-ras oncogenes in 38 lung cancer samples derived from Japanese patients who worked in the chromate industry for long periods. We used both radioactive isotope and non-radioisotope PCR-SSCP techniques. RESULTS: The results of this study demonstrated that activation of ras genes due to point mutations in chromate-related lung cancer is a rare event. CONCLUSIONS: Ras oncogenes activated by point mutations do not have a major role in the process of tumorigenesis of chromate-related lung cancer.     

Novel 2,4,5-trisubstituted oxazole derivatives: Synthesis and antiproliferative activity

Microwave irradiation promotes the rapid O,N-acylation–cyclodehydration cascade reaction of oximes and acid chloride. Twenty novel 2,4,5-trisubstituted oxazole derivatives containing heterocycle moiety were synthesized and evaluated for their antiproliferative activity. The twenty compounds are all first reported and their structures were established by elemental analysis, ¹H NMR and ¹³C NMR spectra. The bioassay tests showed that compounds 2-(2-(2-fluorophenyl)-4-(2,3,4-trimethoxyphenyl)oxazol-5-ylthio)benzo[d]thiazole (6af), 2-(2-(pyridin-3-yl)-4-(2,3,4-trimethoxyphenyl)oxazol-5-ylthio)pyrimidine (6bg) and 2-(2-(2-fluorophenyl)-4-(2,3,4-trimethoxyphenyl)oxazol-5-ylthio)-5-methyl-1,3,4-thiadiazole (6cf) displayed good antiproliferative activity in vitro, which were comparable to the positive control (5-fluorouracil).     

Novel 1,3,4-heterodiazole analogues: synthesis and in-vitro antitumor activity

The synthesis of some new heterodiazole and their annulated imidazo[2,1-b]1,3,4-oxa/thiadiazolone 6a-d, 7a-d; 1,3,4-oxa or thiadiazole[3,2-a]pyrimidine diamine 8a-d and 1,3,4-oxa or thiadiazole-3-piperidino-1-propamide 11a,b derivatives have been described. The obtained compounds were evaluated for their in-vitro antitumor activity. A single dose (10?μM) of the test compounds were used in the full National Cancer Institute (NCI) 60 cell lines panel assay. Compounds 6c and 6d displayed appreciable anticancer activity against leukemia, non-small cell lung, CNS and showed moderate activity against colon, melanoma, and breast cancer cells lines. Compound 6c possessed remarkable broad-spectrum antitumor activity which almost 4 fold more active than the known drug 5-FU with GI(50), TGI, and LC(50) values of 6.0, 17.4, and 55.1?μM, respectively.     

Chikungunya virus adaptation to a mosquito vector correlates with only few point mutations in the viral envelope glycoprotein

Like most arthropod-borne viruses (arboviruses), chikungunya virus (CHIKV) is a RNA virus maintained in nature in an alternating cycle of replication between invertebrate and vertebrate hosts. It has been assumed that host alternation restricts arbovirus genome evolution and imposes fitness trade-offs. Despite their slower rates of evolution, arboviruses still have the capacity to produce variants capable to exploit new environments.To test whether the evolution of the newly emerged epidemic variant of CHIKV (E1-226V) is constrained by host alternation, the virus was alternately-passaged in hamster-derived BHK-21 cells and Aedes aegypti-derived Aag-2 cells. It was also serially-passaged in BHK-21 or Aag-2 cells to promote adaptation to one cell type and presumably, fitness cost in the bypassed cell type. After 30 passages, obtained CHIKV strains were genetically and phenotypically characterized using in vitro and in vivo systems.Serially- and alternately-passaged strains can be distinguished by amino-acid substitutions in the E2 glycoprotein, responsible for receptor binding. Two substitutions at positions E2-64 and E2-208 only lower the dissemination of the variant E1-226V in Ae. aegypti. These amino-acid changes in the E2 glycoprotein might affect viral infectivity by altering the interaction between CHIKV E1-226V and the cellular receptor on the midgut epithelial cells in Ae. aegypti but not in Aedes albopictus.     

用PCR—SSCP方法检测间皮瘤组织中p53基因点突变

为研究石棉纤维在人恶性间皮瘤病因学中的作用，检查了青石棉污染区１２例间皮瘤ＤＮＡ样品的ｐ５３基因点突变。应用非同位素ＰＣＲ－ＳＳＣＰ方法，聚丙烯酰胺凝胶电泳分析了ｐ５３基因５，６，７，８外显子的４个ＤＮＡ片段，结果显示：４例有异常移动的单链ＤＮＡ电泳带，其中２例位于外显子５，２例位于外显子６。提示：这些病例的ｐ５３基因存在点突变     

High frequency of AML1/RUNX1 point mutations in radiation-associated myelodysplastic syndrome around Semipalatinsk nuclear test site

It is known that bone marrow is a sensitive organ to ionizing radiation, and many patients with acute myeloid leukemia (AML) or myelodysplastic syndrome (MDS) have been diagnosed in radiation-treated cases and atomic bomb survivors in Hiroshima and Nagasaki. The AML1/RUNX1 gene has been known to be frequently mutated in MDS/AML patients among atomic bomb survivors and radiation therapy-related MDS/AML patients. In this study, we investigated the AML1 mutations in radiation-exposed patients with MDS/AML among the residents near the Semipalatinsk Nuclear Test Site (SNTS), where the risk of solid cancers and leukemias was increased due to the radiation effects. AML1 mutations were identified in 7 (39%) of 18 radiation-exposed MDS/AML patients. In contrast, no AML1 mutation was found in 13 unexposed MDS/AML cases. The frequency of AML1 mutations in radiation-exposed patients with MDS/AML was significantly higher compared with unexposed patients (p < 0.05).We also found a significant correlation between individual estimated doses and AML1 mutations (p < 0.05). Considering these results, AML1 point mutations might be a useful biomarker that differentiates radio-induced MDS/AML from spontaneous MDS/AML.     

Rapid detection of point mutations in domain V of the 23S rRNA gene in erythromycin-resistant Campylobacter isolates by pyrosequencing

Campylobacter is one of the most common foodborne pathogens causing acute gastroenteritis in humans. Erythromycin, a macrolide antibiotic, is the first-choice treatment for Campylobacter infections, and failure to eradicate Campylobacter is usually due to macrolide resistance. The most important mechanism responsible for macrolide resistance in Campylobacter is mediated by point mutations at position 2074 or 2075 in the peptidyl-transferase region of domain V of the 23S rRNA gene. In this study, the minimum inhibitory concentrations of 58 Campylobacter isolates (C. jejuni: n?=?37; C. coli: n?=?21) obtained from chickens were measured by agar dilution. Isolates were subjected to both pyrosequencing and Sanger sequencing methods to detect the 2074 and 2075 point mutations and evaluate the efficacy of the pyrosequencing method. The A2075G mutation was found to be the predominant mutation associated with erythromycin resistance. Compared with traditional methods, pyrosequencing is a novel, rapid, low-cost, and quantitative technology for detecting erythromycin resistance in Campylobacter.     

Novel substituted quinoxaline 1,4-dioxides with in vitro antimycobacterial and anticandida activity

Thirty-six 6(7)-substituted-3-methyl- or 3-halogenomethyl-2-phenylthio-phenylsulphonyl-chloro-quinoxaline 1,4-dioxides belonging to series 3-6 were synthesised and submitted to a preliminary in vitro evaluation for antimycobacterial, anticandida and antibacterial activities. Antitubercular screening showed a generally good activity of 3-methyl-2-phenylthioquinoxaline 1,4-dioxides (3d,e,h-j) against Mycobacterium tuberculosis, and exhibited MIC between 0.39 and 0.78 microg mL(-1) (rifampicin MIC=0.25 microg mL(-1)), whereas in compounds 4d,e, 5a,b,d,e,l and 6b-e,j,l MIC ranged between 1.56 and 6.25 microg mL(-1). Results of the antibacterial and anticandida screening showed that 6e and 6l exhibited MIC=0.4 and 1.9 microg mL(-1), respectively, against Candida krusei (miconazole MIC=0.9 microg mL(-1)), and 4i, 5b,d, 6e, MIC=3.9 microg mL(-1) against Candida glabrata (miconazole MIC=0.4 microg mL(-1)), while compounds 3d,l, 5e,l, and 6b,d,e,l showed MIC=15.6 microg mL(-1) against Vibrio alginolyticus.     

High Plasmodium falciparum resistance to chloroquine and sulfadoxine-pyrimethamine in Harper,Liberia: results in vivo and analysis of point mutations

In Liberia, little information is available on the efficacy of antimalarials against Plasmodium falciparum malaria. We measured parasitological resistance to chloroquine and sulfadoxine-pyrimethamine (SP) in Harper, south-west Liberia in a 28-d study in vivo. A total of 50 patients completed follow-up in the chloroquine group, and 66 in the SP group. The chloroquine failure rate was 74.0% (95% confidence interval [95% CI] 59.7-85.4%) after 14 d of follow-up and 84.0% (95% CI 70.9-92.8%) after 28 d (no polymerase chain reaction [PCR] analysis was performed to detect reinfections in this group). In the SP group, the failure rate was 48.5% (95% CI 36.2-61.0%) after 14 d and 69.7% (95% CI 57.1-80.4%) after 28 d, readjusted to 51.5% (95% CI 38.9-64.0%) after taking into account reinfections detected by PCR. Genomic analysis of parasite isolates was also performed to look for point mutations associated with resistance. Genotyping of parasite isolates revealed that all carried chloroquine-resistant K-76T mutations at gene pfcrt, whereas the triple mutation (S108N, N511, C59R) at dhfr and the A437G mutation at dhps, both associated with resistance to SP, were present in 84% and 79% of pretreatment isolates respectively. These results seriously question the continued use of chloroquine and SP in Harper and highlight the urgency of making alternative antimalarial therapies available. Our study confirms that resistance to chloroquine may be high in Liberia and yields hitherto missing information on SP.     

Soy isoflavones attenuate bone loss in early postmenopausal Chinese women

Background Previous studies show that daily doses of 40–99 mg soy isoflavones produce inconsistent effects on preventing estrogen-related bone loss in postmenopausal women. Aim of the study To examined the bone-sparing effect of isoflavones at a higher dose in early Chinese postmenopausal women. Methods A total of 90 eligible women aged 45–60 years were randomly assigned to three treatment groups (30 subjects/group) with daily dosages of 0 (placebo), 84 and 126 mg isoflavones for 6 months. Further inclusion criteria included body mass index <30 kg/m² and Kuppermann Climacteric Scale >15. Bone mineral density (BMD) of the spine and hip were measured using dual- energy X-ray absorptiometry at 0 and 6 months. Serum osteocalcin, bone-specific alkaline phosphatase (BAP) and urinary deoxypyridinoline were examined at 0, 3 and 6 months. Results Mean percent changes in BMD at the lumbar spine (p = 0.114) and femoral neck (p = 0.053) increased with the supplementations of soy isoflavones after adjusting for age, years since menopause, body weight and height, dietary intakes of isoflavones, calcium and protein, physical activities and baseline BMD at the relevant sites. We observed significantly dose-dependent linear relationship between the supplemental isoflavones and percent changes of BMD at the spine (p = 0.042) and femoral neck (p = 0.016) post-treatment, and urinary total deoxypyridinoline (p = 0.014) at 12 weeks but not at 24 weeks after adjusting for the above factors. No significant difference in percent changes in serum osteocalcin (p > 0.05) and BAP (p > 0.05) was found among the three treatment groups at 12-week and 24-week post-treatment. Conclusion There is a significantly dose-dependent effect of soy isoflavones on attenuating bone loss at the spine and femoral neck possibly via the inhibition of bone resorption in non-obese postmenopausal Chinese women with high Kuppermann Scale.     

Early handling can attenuate adverse effects of fetal ethanol exposure

The effects of early handling on physiological and hormonal responses of rats exposed to ethanol prenatally were studied. Male and female Sprague-Dawley rats from prenatal ethanol (E), pair-fed (PF), and ad lib-fed control (C) prenatal treatment groups were either handled (H) or nonhandled (NH) during the preweaning period and tested in adulthood. Early handling eliminated the deficit in preweaning weight gain observed in E compared to PF and C offspring. In adulthood, early handling eliminated the increased hypothermia observed in E and PF compared to C males following an ethanol challenge (2.0 g/kg, IP). In addition, H males displayed marginally less hypothermia overall than NH males. In contrast, handling accelerated the return to preinjection temperature in PF and C females but had no effect on E females. There were no significant differences among E, PF, and C rats in corticosterone (CORT) responses to ethanol challenge (1.5 g/kg, IP), but both males (marginally) and females in the H condition displayed higher CORT levels overall than NH rats. Early handling also eliminated the increased peak CORT response to restraint stress in E compared to C females, but did not affect the more prolonged elevation of CORT in E compared to PF and C females. There were no differences among E., PF, and C females in hippocampal type I and type II glucocorticoid receptor density or affinity. However, binding affinity of type II receptors was slightly but significantly increased in H compared to NH females. Together, these data indicate that early handling may modulate or attenuate some, but not all, of the adverse effects of fetal ethanol exposure on offspring growth and physiological responsiveness.