Effect of vitamin A pretreatment on Escherichia coli-induced lipid peroxidation and level of 3-nitrotyrosine in kidney of guinea pig

In the present study, we report the effect of vitamin A (Vit A, retinol palpitate) on kidney lipid peroxidation and 3-nitrotyrosine (3-NT) levels induced after Escherichia coli administration to guinea pigs. Vit A was administrated intraperitoneally (i.p.) to guinea pigs at a dose 15,000 IU/kg per day for 7 days prior to E. coli injection. On day 8, the animals were injected i.p. with E. coli dosed at 12 ×10⁹ colony forming units per kilogram. Kidneys were collected 6 h after administration of E. coli. Malondialdehyde (MDA) as a lipid peroxidation product, and 3-NT levels were measured by reverse phase high-performance liquid chromatography. There was a significant increase in MDA and 3-NT levels in lipopolysaccaharide-induced group (p<0.001). 3-NT was not detectable in kidney of normal control animals. However, Vit A administration prior to E. coli injection prevented 3-NT formation but did not prevent the rice in MDA level of kidney (p<0.001). Vit A alone did not alter the MDA level in the kidney of the control group. (Mol Cell Biochem 278: 33–37, 2005)     

A prospective epidemiologic survey on the prevalence of onychomycosis and dermatophytosis in male boarding school residents

Dermatophyte infections and onychomycosis are not usually serious in term of mortality; however, they may have significant clinical consequences such as secondary bacterial infections, chronicity, therapeutic difficulties and esthetic disfigurement in addition to serving as a reservoir of infection. Our aim was to determine the prevalence of onychomycosis and dermatophytosis in a selected high risk group, consisting of male boarding school residents. A total of 410 males inhabiting two houses were evaluated by two dermatologists. In cases of clinical suspicion, appropriate samples were taken for direct microscopy and culture. The results showed that the prevalences of tinea pedis (athletes foot) and pure pedal onychomycosis were 51.5% (n:211) and 4.4% (n:18), respectively. Thirty cases of those with tinea pedis were complicated by toenail onychomycosis. Tinea cruris was present only in five cases with tinea pedis. Interestingly 71.1% of those with tinea pedis and 45.8% of those with onychomycosis, associated with or without tinea pedis were unaware of their diseases. The most common fungal isolate was Trichophyton rubrum (76.6%) followed by Epidermophyton floccosum (11.6%), T. interdigitale (10.55%). Approximately one third of the cultures from nail specimens yielded pure growths of nondermatophyte moulds or Candida albicans. In conclusion, we found unexpectedly high prevalences of occult athletes foot and toenail onychomycosis among the male residents of student houses. Our results indicate that health-care workers of such common boarding-houses should be more aware of clinical and subclinical dermatophyte infections and onychomycosis, and have more active approaches to educational measures and management strategies to prevent further infections. To our knowledge, this is the first epidemiologic study on the prevalences of dermatophytosis and onychomycosis in boarding-houses from Turkey.     

Antibacterial, antifungal, and antiviral activities of the lipophylic extracts of Pistacia vera

In the present study, antibacterial, antifungal, and antiviral properties of 15 lipohylic extracts obtained from different parts (leaf, branch, stem, kernel, shell skins, seeds) of Pistacia vera were screened against both standard and the isolated strains of Escherichia coli, Pseudomonas aeruginosa, Enterococcus faecalis, Staphylococcus aureus, Candida albicans and C. parapsilosis by microdilution method. Both Herpes simplex (DNA) and Parainfluenza viruses (RNA) were used for the determination of antiviral activity of the P. vera extracts by using Vero cell line. Ampicilline, ofloxocine, ketoconazole, fluconazole, acyclovir and oseltamivir were used as the control agents. The extracts showed little antibacterial activity between the range of 128-256 microg/ml concentrations whereas they had noticeable antifungal activity at the same concentrations. Kernel and seed extracts showed significant antiviral activity compared to the rest of the extracts as well as the controls.     

Cholesterol dictates the freedom of EGF receptors and HER2 in the plane of the membrane

The flow of information through the epidermal growth factor receptor (EGFR) is shaped by molecular interactions in the plasma membrane. The EGFR is associated with lipid rafts, but their role in modulating receptor mobility and subsequent interactions is unclear. To investigate the role of nanoscale rafts in EGFR dynamics, we used single-molecule fluorescence imaging to track individual receptors and their dimerization partner, human epidermal growth factor receptor 2 (HER2), in the membrane of human mammary epithelial cells. We found that the motion of both receptors was interrupted by dwellings within nanodomains. EGFR was significantly less mobile than HER2. This difference was likely due to F-actin because its depolymerization led to similar diffusion patterns between the EGFR and HER2. Manipulations of membrane cholesterol content dramatically altered the diffusion pattern of both receptors. Cholesterol depletion led to almost complete confinement of the receptors, whereas cholesterol enrichment extended the boundaries of the restricted areas. Interestingly, F-actin depolymerization partially restored receptor mobility in cholesterol-depleted membranes. Our observations suggest that membrane cholesterol provides a dynamic environment that facilitates the free motion of EGFR and HER2, possibly by modulating the dynamic state of F-actin. The association of the receptors with lipid rafts could therefore promote their rapid interactions only upon ligand stimulation.     

Glutathione S-Transferase M1, T1, P1 Genotypes and Risk for Development of Colorectal Cancer

The glutathione S-transferase (GST) supergene family is an important part of cellular enzyme defense against endogenous and exogenous chemicals, many of which have carcinogenic potential. The present investigation was conducted to detect a possible association between polymorphisms at the GSTM1, GSTT1, and GSTP1 genes and the interaction with cigarette smoking and colorectal cancer incidence. We examined 181 patients with colorectal cancer and 204 controls. DNA was extracted from whole blood, and the GSTM1, GSTT1, and GSTP1 polymorphisms were determined using a real-time polymerase chain reaction and fluorescence resonance energy transfer with a Light-Cycler instrument. Associations between specific genotypes and the development of colorectal cancer were examined by use of logistic regression analysis to calculate odds ratios (OR) and 95% confidence intervals (CI). The GSTM1 polymorphism was associated with an increased risk of developing colorectal cancer (OR = 1.62, 95% CI: 1.06–2.46). Also the risk of colorectal cancer associated with the GSTT1 null genotype was 1.64 (95% CI: 1.10–2.59). Statistically no differences were found between patients with colorectal cancer and control groups for the GSTP1 Ile/Ile, Ile/Val and Val/Val genotypes. In addition, the frequencies of the GSTM1 and GSTT1 deletion genotypes differed significantly between the cases and controls for current smokers; the GSTT1 null genotype especially is associated with a greater risk of colorectal cancer (OR = 2.44, 95% CI: 1.24–4.81). The GSTM1 and GSTT1 deletions were associated with an increased risk of developing a transverse or rectal tumor (OR = 1.86, 95% CI: 1.15–3.00; OR = 1.70, 95% CI: 1.02–2.84; respectively). The glutathione S-transferase polymorphisms were not associated with risk in patients stratified by age. The risk of colorectal cancer increased as putative high-risk genotypes increased for the combined genotypes of GSTM1 null, GSTT1 null, and either GSTP1 valine heterozygosity or GSTP1 valine homozygosity (OR = 2.69, 95% CI: 1.02–7.11). In conclusion, the results obtained in this study clearly suggest that those susceptibility factors related to different GST polymorphic enzymes are predisposing for colorectal cancer.     

The Effects of Triiodothyronine on Rat Testis: A Morphometric and Immunohistochemical Study

The aim of present study was to investigate the effects of 3,3′,5-triiodothyronine (T₃) on rat testis both morphometrically and immunohistochemically with determining of insulin-like growth factor I (IGF-I) expression. Adult male Wistar-albino rats used in the study were divided into two groups; control and T₃-treated groups. After T₃ treatment there was observed to be a decrease in testicular weights, diameters of seminiferous tubules and the number of sertoli cells, and an increase in the number of leydig cells (P<0.05). Some of the seminiferous tubule lumens of T₃ administrated rats had cellular debris. IGF-I was localized in sertoli cells, late spermatids and leydig cells of all groups. IGF-I immunoreactivity in T₃ treated rats was higher than in controls in all stages of the cycle of rat seminiferous epithelium, but the staining intensity of leydig cells were similar in both groups. In conclusion, the present results suggest that T₃ may modulate the testicular function by affecting IGF-I activity at the gonadal level.     

High-pressure liquid chromatographic analysis for identification of in vitro and in vivo metabolites of 4-phenethyl-5-[4-(1-(2-hydroxyethyl)-3,5-dimethyl-4-pyrazolylazo)phenyl]-2,4-dihydro-3H-1,2,4-triazole-3-thione in rats

All azo colorants whose metabolism can liberate a carcinogenic arylamine, are suspected of having carcinogenic potential. Therefore, a new azo compound 4-phenethyl-5-[4-(1-(2-hydroxyethyl)-3,5-dimethyl-4-pyrazolylazo)phenyl]-2,4-dihydro-3H-1,2,4-triazole-3-thione (substrate) was prepared to investigate its in vitro and in vivo biotransformation in rats by HPLC. Chromatographic separation of substrate and its metabolites was performed using a Chromasil C(18) column. The mobile phase consisted of acetonitrile and water in a linear gradient system. From the biotransformation of this compound, the reduction metabolite 4-(2-phenethyl)-5-(4-aminophenyl)-2,4-dihydro-3H-1,2,4-triazole-3-thione was identified by comparing it to reference standard by HPLC-DAD. In the in vivo study, identification of the unknown peak which was the N-acetylation metabolite was confirmed by LC-MS spectrometry. Besides this, the azo compound was reduced to its corresponding amine in intestinal and cytosolic parts. In addition, oxidation of the methyl group and the phenyl ring, and reduction of azo group to hydrazo were identified in the cytosolic part using LC-MS.     

Genetic evidence for high propagule pressure and long‐distance dispersal in monk parakeet (Myiopsitta monachus) invasive populations

The monk parakeet (Myiopsitta monachus) is a successful invasive species that does not exhibit life history traits typically associated with colonizing species (e.g., high reproductive rate or long‐distance dispersal capacity). To investigate this apparent paradox, we examined individual and population genetic patterns of microsatellite loci at one native and two invasive sites. More specifically, we aimed at evaluating the role of propagule pressure, sexual monogamy and long‐distance dispersal in monk parakeet invasion success. Our results indicate little loss of genetic variation at invasive sites relative to the native site. We also found strong evidence for sexual monogamy from patterns of relatedness within sites, and no definite cases of extra‐pair paternity in either the native site sample or the examined invasive site. Taken together, these patterns directly and indirectly suggest that high propagule pressure has contributed to monk parakeet invasion success. In addition, we found evidence for frequent long‐distance dispersal at an invasive site (～100 km) that sharply contrasted with previous estimates of smaller dispersal distance made in the native range (～2 km), suggesting long‐range dispersal also contributes to the species’ spread within the United States. Overall, these results add to a growing body of literature pointing to the important role of propagule pressure in determining, and thus predicting, invasion success, especially for species whose life history traits are not typically associated with invasiveness.     

The effects of Se phytotoxicity on the antioxidant systems of leaf tissues in barley (Hordeum vulgare L.) seedlings

A hydroponic experiment was carried out in a growth chamber to investigate the impact of Selenium (Se) levels on physiological and biochemical characteristics of a barley cultivar. Membrane lipid peroxidation (LPO), proline accumulation and antioxidant activities of some enzymes of barley seedlings under Se toxicity were investigated. Significant increase in thiobarbituric acid reactive substance (TBARS) content, and a stimulation of catalase (CAT, 1.11.1.6), ascorbate peroxidase (APX, 1.11.1.11), glutathione reductase (GR, 1.6.4.2), and glutathione S-transferase (GST, 2.5.1.18) activities were recorded in barley seedlings subjected to 2, 4, 8, 16 ppm Se. Superoxide dismutase (SOD, EC 1.15.1.1) activity was not altered significantly. Plant height and chlorophyll content of the seedlings were also affected significantly in a dose dependent manner by Se treatment. Considerable amount of proline accumulation was also observed in response to Se treatment. The results indicated that increases in the activities of the antioxidant enzymes were not sufficient to protect cell membrane against Se toxicity.     

Identifying hybridizing taxa within the <Emphasis Type="Italic">Daphnia longispina</Emphasis> species complex: a comparison of genetic methods and phenotypic approaches

Daphnia galeata Sars, D. longispina O. F. Müller and D. cucullata Sars (Crustacea: Cladocera) are closely related species which often produce interspecific hybrids in natural populations. Several marker systems are available for taxon determination in this hybridizing complex, but their performance and reliability has not been systematically assessed. We compared results from identifications by three molecular methods. More than 1,200 individuals from 10 localities in the Czech Republic were identified as parental species or hybrids by allozyme electrophoresis and the analysis of the restriction fragment length polymorphism of the internal transcribed spacer (ITS-RFLP); over 440 of them were additionally analyzed and identified by 12 microsatellite loci. Identification by microsatellite markers corresponded well with allozyme analyses. However, consistent discrepancies between ITS-RFLP and other markers were observed in two out of 10 studied localities. Although some marker discrepancies may have been caused by occasional recent introgression, consistent deviations between ITS-RFLP and other markers suggest a long-term maintenance of introgressed alleles. These results warn against its use as a sole identification method in field studies. Additionally, we quantitatively evaluated the discriminatory power of geometric morphometric (elliptic Fourier) analysis of body shapes based on photos of over 1,300 individuals pre-classified by allozyme markers. Furthermore, a randomly selected subset of 240 individuals was independently determined from photos by several experts. Despite a tendency for morphological divergence among parental Daphnia species, some taxa (especially D. galeata, D. longispina, and their hybrids) substantially overlapped in their body shapes. This was reflected in different determination success for particular species and hybrids in discriminant analysis based on shape data as well as from photographs.