Impact of Aging Time on the Dermal Penetration of Phenol in Soil

Phenol is released to soil through accidental spills, manufacturing processes, and waste disposal. With time, chemicals can become more sequestered in soil (aging). Since skin is the body's primary route of entry for phenol, the impact of aging time on the dermal penetration of phenol was assessed in Atsion and Keyport soils. In vitro studies were conducted on dermatomed male pig skin using a flow-through diffusion cell methodology and radiolabeled phenol. After 3 and 6 months of aging in the Atsion soil, dermal penetration decreased from 84% of the initial dose for pure phenol (without soil) to 15% and 8%, respectively, while the dermal penetration of phenol aged in the Keyport soil was reduced to 22% and 17%, respectively. Atsion soil has a higher organic matter content (4.4%) than Keyport soil (1.6%) suggesting that the lower bioavailability of phenol aged in the Atsion soil may be due to the amount of organic matter in that soil. Although the data indicate that the potential health risk from dermal exposure to phenol would be lower after aging in soil than to pure chemical, further experiments are warranted at lower soil loads and with additional concentrations of phenol to quantify the risk.     

Nischarin as a functional imidazoline (I1) receptor

Gene matching shows that Nischarin is a mouse homologue of human imidazoline receptor antisera-selective (IRAS) protein, a viable candidate of the imidazoline (I1) receptor. Nischarin and IRAS share the functions of enhancing cell survival, growth and migration. Bioinformatics modeling indicates that the IRAS and Nischarin may be transmembrane proteins and the convergence information raises the interesting possibility that Nischarin might serve as the I1-receptor. To test this hypothesis, we developed antibodies against the Nischarin protein, and conducted signal transduction (functional) studies with the I1-receptor agonist rilmenidine in the presence and absence of Nischarin antisense oligodeoxynucleotides (ODNs). NIH3T3 cells transfected with the Nischarin cDNA and incubated with the newly synthesized antibody expressed a 190 kD band. The antibody identified endogenous Nischarin in differentiated PC12 cells around 210 kD, which is consistent with reported findings in other cells of neuronal origin. The immunoflourescence findings showed the targeted protein to be associated with the cell membrane in PC12 cells. Nischarin ODNs abolished the expression of Nischarin in PC12 cells. Equally important, the Nischarin ODNs eliminated the production of MAPK(p42/44), a recognized signal transduction product generated by I1-receptor activation in differentiated PC12 cells. Together, the present findings suggest that Nischarin may serve as the functional I1-receptor or at least share a common signaling pathway in the differentiated PC12 cells.     

Synthesis of 2-bromomethyl-3-hydroxy-2-hydroxymethyl-propyl pyrimidine and theophylline nucleosides under microwave irradiation. Evaluation of their activity against hepatitis B virus

Alkylation of 2-methylthiopyrimidin-4(1H)-one (1a) and its 5(6)-alkyl derivatives 1b-d as well as theophylline (7) with 2,2-bis(bromomethyl)-1,3-diacetoxypropane (2) under microwave irradiation gave the corresponding acyclonucleosides 1-[(3-acetoxy-2-acetoxymethyl-2-bromomethyl)prop-1-yl]-2-methyl-thio pyrmidin-4(1H)-ones 3a-d and 7-[(3-acetoxy-2-acetoxymethyl-2-bromomethyl)prop-1-yl]theophylline (8), which upon further irradiation gave the double-headed acyclonucleosides 1,1 '-[(2,2-diacetoxymethyl)-1,3-propylidene]-bis[(2-(methylthio)-pyrimidin-4(1H)-ones] 4a-c, and 7,7 '-[(2,2-diacetoxymethyl)-1,3-propylidene]-bis(theophylline) (9). The deacetylated derivatives were obtained by the action of sodium methoxide. The activity of deacetylated nucleosides against Hepatitis B virus was evaluated. Compound 5b showed moderate inhibition activity against HBV with mild cytotoxicity.     

Synthesis and biological evaluation of colchicine C-ring analogues tethered with aliphatic linkers suitable for prodrug derivatisation

Colchicine was modified at the 10-OCH₃ position of the C-ring by reaction with heterocyclic amines or commercially available amines to afford a library of target colchicinoids in high yields (62–99%). Molecular modeling revealed that the incorporation of the linker groups led to a reduction in entropy and therefore binding affinity when compared with colchicine. Some colchicinoids were shown to be equicytotoxic with colchicine when evaluated in the DLD-1 colon cancer cells and retained activity in resistant A2780AD or HeLa cells with mutant Class III β-tubulin. Importantly, unlike colchicine, the analogues in this study are amenable for prodrug derivatisation and with potential for tumor-selective delivery.     

Increased risk of lung cancer associated with a functionally impaired polymorphic variant of the human DNA glycosylase NEIL2

Human NEIL2, one of five oxidized base-specific DNA glycosylases, is unique in preferentially repairing oxidative damage in transcribed genes. Here we show that depletion of NEIL2 causes a 6-7-fold increase in spontaneous mutation frequency in the HPRT gene of the V79 Chinese hamster lung cell line. This prompted us to screen for NEIL2 variants in lung cancer patients' genomic DNA. We identified several polymorphic variants, among which R103Q and R257L were frequently observed in lung cancer patients. We then characterized these variants biochemically, and observed a modest decrease in DNA glycosylase activity relative to the wild type (WT) only with the R257L mutant protein. However, in reconstituted repair assays containing WT NEIL2 or its R257L and R103Q variants together with other DNA base excision repair (BER) proteins (PNKP, Polβ, Lig IIIα and XRCC1) or using NEIL2-FLAG immunocomplexes, an ~5-fold decrease in repair was observed with the R257L variant compared to WT or R103Q NEIL2, apparently due to the R257L mutant's lower affinity for other repair proteins, particularly Polβ. Notably, increased endogenous DNA damage was observed in NEIL2 variant (R257L)-expressing cells relative to WT cells. Taken together, our results suggest that the decreased DNA repair capacity of the R257L variant can induce mutations that lead to lung cancer development.     

Strain Differentiation of Dermatophytes

As molecular-based investigations begin to uncover the large degree of genetic variation that can exist within dermatophyte species, and population-based studies reveal exceedingly high rates of endemicity for these organisms, species typing has become inadequate to gain insight into these pathogens and the nature of the infections that they cause. This review examines studies that have applied strain typing strategies to explore intra-specific genetic diversity among the dermatophytes in attempts to address a number of relevant clinico-epidemiologic questions about these common fungal pathogens.     

Regulation of renal 12(S)-hydroxyeicosatetraenoic acid in diabetes by angiotensin AT1 and AT2 receptors

Diabetes is associated with increased production of 12(S)-hydroxyeicosatetraenoic acid [12(S)-HETE]. The mechanisms involved in this process remain unclear. We hypothesized that hyperglycemia and angiotensin II (ANG II) regulate renal 12(S)-HETE production via a balance between angiotensin AT(1) and AT(2) receptors activities. Using a microdialysis technique, renal interstitial fluid (RIF) levels of ANG II and 12(S)-HETE were monitored in normal control and streptozotocin-induced diabetic rats at baseline and then weekly thereafter for 12 wk. In a second group of normal and diabetic rats, 3 wk after development of diabetes, we monitored RIF 12(S)-HETE levels in response to acute AT(1) receptor blockade with valsartan or AT(2) receptor blockade with PD123319 individually or combined. Two weeks after induction of diabetes there was a 404% increase in ANG II (P < 0.05), a 149% increase in 12S-HETE (P < 0.05), and a 649% increase in urinary albumin excretion (P < 0.05). These levels remained elevated throughout the study. PD123319 given alone had no effect on 12(S)-HETE. Valsartan decreased 12(S)-HETE by 61.6% (P < 0.0001), a response that was abrogated when PD123319 was given with valsartan. These data demonstrate that hyperglycemia increases renal ANG II and 12(S)-HETE levels. The increase in 12(S)-HETE is mediated via AT(1) receptor. The attenuation of the effects of AT(1) receptor blockade by PD123319 suggests that AT(2) receptor contributes to the downregulation of renal 12(S)-HETE production.     

Differential alteration of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) mRNA in the central nervous system of hens treated with diisopropylphosphorofluoridate (DFP).

A single dose (1.7 mg/kg, s.c.) of diisopropylphosphorofluoridate (DFP) causes organophosphorus ester-induced delayed neurotoxicity (OPIDN) in susceptible species. We studied the effects of DFP administration on the mRNA expression of glyceraldehyde-3-phosphate dehydrogenase (GAPDH), an important glycolytic protein at different time points (1, 2, 5, 10 and 20 days) post-treatment. Total RNA was extracted from cerebrum, cerebellum, brainstem, midbrain, and spinal cord of the control and DFP-treated hens, and northern blots were prepared using standard protocols and hybridized with GAPDH, as well as beta-actin and 28S RNA cDNA (control) probes. There was a distinct spatial/temporal mRNA expression pattern for the different tissues studied. Non-susceptible tissue, cerebrum showed a dramatic increase in GAPDH mRNA at day 1, post-treatment and levels remained high at all time points, suggestive of protective mechanisms from the beginning. In contrast, highly susceptible tissues like brainstem, spinal cord and midbrain showed either no elevation or slight down-regulation at day 1, suggesting trauma and cell injury/cell death. Overall, there was moderate level of induction during the subsequent time points in these tissues, indicative of pathways of either recovery or degeneration. Cerebellum being the less susceptible tissue showed moderate increase initially, followed by higher induction, suggestive of rapid recovery. Our current data on GAPDH provides an important link in this complex network of molecular changes involving pathways identified by our group and others, such as nitric oxide (NO), CaM kinase-II (CaMK-II), protein kinase-A (PKA), c-fos, and phosphorylated-CREB (p-CREB) in DFP-induced OPIDN.     

Synthesis of 2-Bromomethyl-3-Hydroxy-2-Hydroxymethyl-Propyl Pyrimidine and Theophylline Nucleosides Under Microwave Irradiation. Evaluation of Their Activity Against Hepatitis B Virus

Alkylation of 2-methylthiopyrimidin-4(1H)-one (1a) and its 5(6)-alkyl derivatives 1b–d as well as theophylline (7) with 2,2-bis(bromomethyl)-1,3-diacetoxypropane (2) under microwave irradia-tion gave the corresponding acyclonucleosides 1-[(3-acetoxy-2-acetoxymethyl-2-bromomethyl)prop-1-yl]-2-methyl-thio pyrmidin-4(1H)-ones 3a–d and 7-[(3-acetoxy-2-acetoxymethyl-2-bromomethyl)prop-1-yl]theophylline (8), which upon further irradiation gave the double-headed acyclonucleosides 1,1 ′-[(2,2-diacetoxymethyl)-1,3-propylidene]-bis[(2-(methylthio)-pyrimidin-4(1H)-ones] 4a–c, and 7,7 ′-[(2,2-diacetoxymethyl)-1,3-propylidene]-bis(theophylline) (9). The deacetylated derivatives were obtained by the action of sodium methoxide. The activity of deacetylated nucleosides against Hepatitis B virus was evaluated. Compound 5b showed moderate inhibition activity against HBV with mild cytotoxicity.     

Design,synthesis and evaluation against Mycobacterium tuberculosis of azole piperazine derivatives as dicyclotyrosine (cYY) mimics

Three series of azole piperazine derivatives that mimic dicyclotyrosine (cYY), the natural substrate of the essential Mycobacterium tuberculosis cytochrome P450 CYP121A1, were prepared and evaluated for binding affinity and inhibitory activity (MIC) against M. tuberculosis. Series A replaces one phenol group of cYY with a C3-imidazole moiety, series B includes a keto group on the hydrocarbon chain preceding the series A imidazole, whilst series C explores replacing the keto group of the piperidone ring of cYY with a CH₂-imidazole or CH₂-triazole moiety to enhance binding interaction with the heme of CYP121A1. The series displayed moderate to weak type II binding affinity for CYP121A1, with the exception of series B 10a, which displayed mixed type I binding. Of the three series, series C imidazole derivatives showed the best, although modest, inhibitory activity against M. tuberculosis (17d MIC?=?12.5?μg/mL, 17a 50?μg/mL). Crystal structures were determined for CYP121A1 bound to series A compounds 6a and 6b that show the imidazole groups positioned directly above the haem iron with binding between the haem iron and imidazole nitrogen of both compounds at a distance of 2.2?Å. A model generated from a 1.5?Å crystal structure of CYP121A1 in complex with compound 10a showed different binding modes in agreement with the heterogeneous binding observed. Although the crystal structures of 6a and 6b would indicate binding with CYP121A1, the binding assays themselves did not allow confirmation of CYP121A1 as the target.