Bioavailability of Soil-Bound TCDD: Dermal Bioavailability in the Rat

Bioavailability of Soil-Bound TCDD: Dermal Bioavailability inthe Rat. SHU, H., TEITELBAUM, T., WEBB, A. S., MARPLE, L., BRUNCK,B. DEI ROSSI, D., MURRAY, J., AND PAUSTENBACH, D. (1988). Fundam.Appl. Toxicol. 10, 335-343. 2,3,7,8-Tetrachlorodibenzo-p-dioxin(TCDD), an unwanted by-product formed during the manufactureof hexachlorophene and phenoxyherbicides, has been found asan environmental contaminant in many U.S. and Western Europeansites. This study examines in the rat the degree of dermal absorptionof TCDD bound to soil. Such information would assist regulatoryagencies in evaluating the degree of exposure of humans whocome in contact with TCDD-contaminated soil. Several parameterswhich may influence dermal absorption were studied, includingTCDD dose, duration of contact, presence of crankcase oil asa co-contaminant, and environmentally contaminated vs laboratory-preparedsoil. The dermal penetration of TCDD following 4 hr of contactwith skin was approximately 60% of that following 24 hr of contact(P 0.05). Following 24 hr of contact with the skin, the degreeof dermal uptake of TCDD contaminated soil was approximately1% of the administered dose. Under the conditions of the presentstudy, the degree of uptake does not appear to be influencedto any significant extent by the concentration of TCDD on soil,the presence of crankcase oil as co-contaminants, or by environmentallyvs laboratory-contaminated soil. Although a number of parametersexamined in this study did not significantly influence the degreeof dermal absorption of TCDD in the rat following 24 hr of contactwith the contaminated soil, the unqualified use of the 1% valueto estimate human exposure would overestimate human exposure,since there is general agreement among researchers that ratskin tends to be more permeable than human skin to highly lipid-solublecompounds such as TCDD.     

Intergenerational instability of the CAG repeat of the gene for Machado- Joseph disease (MJD1) is affected by the genotype of the normal chromosome: implications for the molecular mechanisms of the instability of the CAG repeat

Machado-Joseph disease (MJD) is an autosomal dominant neurodegenerative disorder caused by unstable expansion of a CAG repeat in the MJD1 gene at 14q32.1. To identify elements affecting the intergenerational instability of the CAG repeat, we investigated whether the CGG/GGG polymorphism at the 3' end of the CAG repeat affects intergenerational instability of the CAG repeat. The [expanded (CAG)n-CGG]/[normal (CAG)n- GGG] haplotypes were found to result in significantly greater instability of the CAG repeat compared to the [expanded (CAG)n- CGG]/[normal (CAG)n-CGG] or [expanded (CAG)nGGG]/[normal (CAG)n-GGG] haplotypes. Multiple stepwise logistic regression analysis revealed that the relative risk for a large intergenerational change in the number of CAG repeat units (< -2 or > 2) is 7.7-fold (95% CI: 2.5-23.9) higher in the case of paternal transmission than in that of maternal transmission and 7.4-fold (95% CI: 2.4-23.3) higher in the case of transmission from a parent with the [expanded (CAG)n-CGG]/[normal (CAG)n-GGG] haplotypes than in that of transmission from a parent with the [expanded (CAG)n-CGG]/[normal (CAG)n-CGG] or [expanded (CAG)n- GGG]/[normal (CAG)n-GGG] haplotypes. The combination of paternal transmission and the [expanded (CAG)n-CGG]/[normal (CAG)n-GGG] haplotypes resulted in a 75.2-fold (95% CI: 9.0-625.0) increase in the relative risk compared with that of maternal transmission and the [expanded (CAG)n-CGG]/[normal (CAG)n-CGG] or [expanded (CAG)n- GGG]/[normal (CAG)n-GGG] haplotypes. The results suggest that an inter- allelic interaction is involved in the intergenerational instability of the expanded CAG repeat.      

Chromosomal aberrations and micronucleus frequency in nurses occupationally exposed to cytotoxic drugs

In this study, we evaluated the effect of low level occupationalexposure of nurses in a medical oncology unit in Cairo, Egypt,to anticancer drugs. Twenty nurses who constantly handled thesedrugs and 20 controls, matched according to age and sex, wereexamined. Metaphase chromosomes were studied. Percentages ofmetaphases with chromosomal aberrations were significantly higher(P < 0.001) in the exposed group (6.1 ± 2.7) versusthe controls (2.6 ± 1.6). The detected chromosomal aberrationswere in the form of chromatid gaps, chromatid breaks and acentricfragments. Micronucleated peripheral blood lymphocytes werealso analyzed in cytochalasin B treated binucleated lymphocytes.There was significant increase in cells with micronuclei (P< 0.001) in nurses (10.05 ± 4.71) in comparison tothe matched control (5.42 ± 2.22) (P < 0.001). Nursesexposed to the cytotoxic drugs for     

The mouse Mid1 gene: implications for the pathogenesis of Opitz syndrome and the evolution of the mammalian pseudoautosomal region

We have recently reported isolation of the gene responsible for X- linked Opitz G/BBB syndrome, a defect of midline development. MID1 is located on the distal short arm of the human X chromosome (Xp22. 3) and encodes a novel member of the B box family of zinc finger proteins. We have now cloned the murine homolog of MID1 and performed preliminary expression studies during development. Mid1 expression in undifferentiated cells in the central nervous, gastrointestinal and urogenital systems suggests that abnormal cell proliferation may underlie the defect in midline development characteristic of Opitz syndrome. We have also found that Mid1 is located within the mouse pseudoautosomal region (PAR) in Mus musculus , while it seems to be X- specific in Mus spretus. Therefore, Mid1 is likely to be a recent acquisition of the M. musculus PAR. Genetic and FISH analyses also demonstrated a high frequency of unequal crossovers in the murine PAR, creating spontaneous deletion/duplication events involving Mid1. These data provide evidence for the first time that genetic instability of the PAR may affect functionally important genes. In addition, we show that MID1 is the first example of a gene subject to X-inactivation in man while escaping it in mouse. These data contribute to a better understanding of the molecular content and evolution of the rodent PAR.      

Quantitative assessment of the contribution of sodium‐dependent taurocholate co‐transporting polypeptide (NTCP) to the hepatic uptake of rosuvastatin,pitavastatin and fluvastatin

Hepatic uptake transport is often the rate‐determining step in the systemic clearance of drugs. The ability to predict uptake clearance and to determine the contribution of individual transporters to overall hepatic uptake is therefore critical in assessing the potential pharmacokinetic and pharmacodynamic variability associated with drug–drug interactions and pharmacogenetics. The present study revisited the interaction of statin drugs, including pitavastatin, fluvastatin and rosuvastatin, with the sodium‐dependent taurocholate co‐transporting polypeptide (NTCP) using gene transfected cell models. In addition, the uptake clearance and the contribution of NTCP to the overall hepatic uptake were assessed using in vitro hepatocyte models. Then NTCP protein expression was measured by a targeted proteomics transporter quantification method to confirm the presence and stability of NTCP expression in suspended and cultured hepatocyte models. It was concluded that NTCP‐mediated uptake contributed significantly to active hepatic uptake in hepatocyte models for all three statins. However, the contribution of NTCP‐mediated uptake to the overall active hepatic uptake was compound‐dependent and varied from about 24% to 45%. Understanding the contribution of individual transporter proteins to the overall hepatic uptake and its functional variability when other active hepatic uptake pathways are interrupted could improve the current prediction practice used to assess the pharmacokinetic variability due to drug–drug interactions, pharmacogenetics and physiopathological conditions in humans. Copyright © 2013 John Wiley & Sons, Ltd.     

In vivo effect of losartan on platelet aggregation in patients with hypertension

The angiotensin II receptor, losartan, has been found to inhibit platelet aggregability to some extent in in vitro experiments. There have been conflicting results about the in vivo effects of losartan. We sought to clarify the in vivo effect of losartan on platelet aggregation. Forty patients with grade I essential hypertension were treated with losartan for 3 weeks. Platelet aggregation tests with adenosine diphosphate (ADP) and ristocetin were analyzed and compared before and at the end of the study. Losartan effectively decreased systolic (SBP) and diastolic (DBP) blood pressure. Mean SBP before and after treatment was 159.6 ± 12.8 and 149.2 ± 17.3mmHg, respectively. Mean DBP decreased from 93.7 ± 8.2 to 87.7 ± 10.3mmHg after treatment. The results of the platelet aggregation tests with ADP and ristocetin were not significantly different when both rate and amplitude of maximal aggregation were included. Peak platelet aggregation with ADP regarding the lowest light transmission in the aggregometer was 59.8% ± 24.3% before and 58.3% ± 18.1% after the treatment. The same variables with ristocetin were 66.8% ± 21.6% and 60.8% ± 23.3%, respectively. In vivo effects of losartan on platelet aggregation with ADP and ristocetin were insignificant.     

Cytomegalovirus colitis in a patient with Behcet’s disease receiving tumor necrosis factor alpha inhibitory treatment

Anti-tumor necrosis factor alpha （TNF-α） inhibitors are effective in the treatment of various inflammatory rheumatic conditions. Increased risks of serious infections are the major issues concerning the long-term safety of these agents. We present a case of a young male Behcet’s patient whose disease was complicated by cytomegalovirus （CMV） colitis. Colitis started 10 d after the third Infliximab dose and responded to the cessation of TNF blocking treatment and administration of ganciclovir. Tumor necrosis factor alpha and interferon gamma act at several levels in combating viral infections.CMV infections should be kept in mind and included in the differential diagnosis of severe gastrointestinal symptoms in patients receiving anti-TNF agents.     

Platelet function and fibrinolytic activity in patients with bronchial asthma.

Platelets have the capacity to release mediators with potent inflammatory or anaphylactic properties. Platelet factor-4 (PF4) and beta-thromboglobulin (BTG) are two of these mediators. On the other hand, plasminogen activator inhibitor-1 (PAI-1) and tissue plasminogen activator (tPA) are two important mediators of fibrinolysis. Both mediators are secreted mainly by vascular endothelium. Plasma levels of PF4, BTG, PAI-1, and tPA may show changes in chronic inflammatory diseases such as asthma. This study examined the role of thrombocytes and the function of the endothelium in asthmatic patients during an attack and during a stable phase. Eighteen patients with known allergic asthma who came to our emergency department with an asthma attack and 14 control subjects were included in the study. Blood samples were taken after starting therapy with salbutamol inhalation. Lung function tests were performed after receiving the first emergency therapy for asthma. Plasma levels of PF4, BTG, PAI-1, tPA were determined before starting steroid therapy and after receiving 1 week of steroid therapy. Plasma levels of PF4 among patients with an asthma attack were significantly higher than those of controls (150.5+/-8.92 IU/mL vs. 92.5+/-7.63 IU/mL, p<0.001). A further increase in plasma PF4 levels was detected after steroid therapy (163.5+/-9.16 IU/mL). Plasma BTG levels of patients on admission were not statistically different from those in the control group (140.4+/-6.34 IU/mL vs. 152.2+/-8.71 IU/mL). An increase was detected after therapy (171.6+/-7.27 IU/mL) and post-treatment plasma levels were statistically meaningful versus the controls. Plasma levels of tPA and PAI were statistically higher than those in controls in asthmatic patients on admission (6.01+/-2.72 vs. 5.4+/-2.3 ng/mL for tPA and 75.2+/-27.2 ng/mL vs. 32.7+/-14.3 ng/mL for PAI-1). Further increases were detected in two parameters after 1 week of therapy with steroids (tPA levels were 6.85+/-2.96 ng/mL and PAI-1 levels were 83.5+/-29.6 ng/mL). There seems to be an increased activity of platelets during an asthma attack. Elevated PAI-1 and tPA levels may also indicate the activated endothelium in asthma. Increases of plasma levels of PAI-1 and tPA after steroid therapy need further investigation because elevated PAI-1 levels enhance airway remodeling.     

Secreted protein, acidic and rich in cysteine-like 1 (SPARCL1) is down regulated in aggressive prostate cancers and is prognostic for poor clinical outcome

Prostate cancer is the second leading cause of cancer death among United States men. However, disease aggressiveness is varied, with low-grade disease often being indolent and high-grade cancer accounting for the greatest density of deaths. Outcomes are also disparate among men with high-grade prostate cancer, with upwards of 65% having disease recurrence even after primary treatment. Identification of men at risk for recurrence and elucidation of the molecular processes that drive their disease is paramount, as these men are the most likely to benefit from multimodal therapy. We previously showed that androgen-induced expression profiles in prostate development are reactivated in aggressive prostate cancers. Herein, we report the down-regulation of one such gene, Sparcl1, a secreted protein, acidic and rich in cysteine (SPARC) family matricellular protein, during invasive phases of prostate development and regeneration. We further demonstrate a parallel process in prostate cancer, with decreased expression of SPARCL1 in high-grade/metastatic prostate cancer. Mechanistically, we demonstrate that SPARCL1 loss increases the migratory and invasive properties of prostate cancer cells through Ras homolog gene family, member C (RHOC), a known mediator of metastatic progression. By using models incorporating clinicopathologic parameters to predict prostate cancer recurrence after treatment, we show that SPARCL1 loss is a significant, independent prognostic marker of disease progression. Thus, SPARCL1 is a potent regulator of cell migration/invasion and its loss is independently associated with prostate cancer recurrence.