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Kushwaha A, Murthy RN, Murthy SN, Elkeeb R, Hui X, Maibach HI. Emerging therapies for the treatment of ungual onychomycosis. Drug Dev Ind Pharm 2015; 41:1575-81. [PMID: 25997365 DOI: 10.3109/03639045.2015.1033426] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
INTRODUCTION Onychomycosis, a common fungal infection in the finger and toe nails, affects approximately 2-8% of the worldwide population. Fungal infection is more complicated in those who suffer from conditions, such as diabetes, peripheral vascular diseases and compromised immune diseases. AREA COVERED Onychomycosis treatment has been classified on the basis of location of infection in the toes and fingers and infectious agents (dermatophytes fungi, yeast and non-dermatophyte molds). In this review, the available therapies (traditional and device based) and their limitations for the treatment of onychomycosis have been discussed. EXPERT OPINION The success rate with topical nail products has been minimal. The main reason for this poor success rate could be attributed to the lack of complete understanding of the pathophysiology of the disease and clinical pharmacokinetic data of drugs in the infected nail apparatus.
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Ren BX, Ji Y, Tang JC, Sun DP, Hui X, Yang DQ, Zhu XL. Effect of Tanshinone IIA intrathecal injections on pain and spinal inflammation in mice with bone tumors. GENETICS AND MOLECULAR RESEARCH 2015; 14:2133-8. [PMID: 25867360 DOI: 10.4238/2015.march.20.24] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
The study aimed to investigate the effect of intrathecal injections of Tanshinone IIA on thermal hyperalgesia in a mouse model of bone cancer-pain. Spinal IL-1β, IL-6, TNF-α expression levels were analyzed. C3H/HeNCrlVr male mice were assigned to groups that either received dose-dependent injections of Tanshinone IIA, or the DMSO + Sham, Tanshinone IIA + Sham, DMSO + Tumor, and Control groups. Paw withdrawal thermal latency (PWTL) was measured with a radiant heat stimulus and mRNA expression levels were determined using real-time PCR. Fourteen days post-injection, PWTL in the DMSO + Tumor group was lower than that in the controls (P < 0.05). Twenty-one days post-injection, compared with the Control group, there was no significant difference in PWTL and IL-1β, IL-6, and TNF-α expression levels between the Tanshinone IIA + Sham and DMSO + Sham groups (P > 0.05). PWTL in the DMSO + Tumor group was significantly lower than the Control group (P < 0.05), while the expression levels of IL-1β, IL-6, and TNF-α were significantly higher than controls. Compared with the DMSO + Tumor group, PWTLs were higher in the Tanshinone IIA - 20-μg and 40-μg groups, while expression levels of IL-1β, IL-6, and TNF-α were significantly lower (P < 0.05). These measures were not significantly different between the Tanshinone IIA 10 μg and the DMSO + Tumor groups (P > 0.05). In conclusion, Tanshinone IIA may inhibit the release of inflammatory cytokines, such as, IL-1 β, IL-6 α, TNF-α.
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Li H, Hui X, Li K, Tang X, Hu X, Xu A, Wu D. High-level expression, purification and characterization of active human C1q and tumour necrosis factor-related protein-1 in Escherichia coli. Lett Appl Microbiol 2014; 59:334-41. [PMID: 24814641 DOI: 10.1111/lam.12280] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 05/05/2014] [Accepted: 05/05/2014] [Indexed: 11/30/2022]
Abstract
UNLABELLED C1q and tumour necrosis factor-related proteins (CTRPs) are a family of adiponectin paralogues. CTRP1 plays important biological functions in diabetes, obesity and hypertension. To further explore the physiological roles of human CTRP1 and its mechanisms of action, hCTRP1 gene was expressed in Escherichia coli. In the E. coli expression system, a large amount of soluble thioredoxin (Trx)-hCTRP1 fusion protein could be produced using the expression plasmid pET32a (+) and induction with IPTG at 18°C, which accounts about 20% of the total soluble bacterial proteins. The recombinant Trx-hCTRP1 fusion protein was purified to an approx. 95% purity using Ni-NTA affinity chromatography and Superdex G-75 column with a yield of about 28-mg protein from 1-l bacterial cultures. The purified recombinant Trx-hCTRP1 was shown to be active under in vivo and in vitro assay conditions. SIGNIFICANCE AND IMPACT OF THE STUDY CTRP1 plays important biological functions and warrants further investigation. However, large-scale production of recombinant CTRP1 has been technically challenging, which becomes a major obstacle in the structural and functional analysis of this important family of proteins. To explore the possible clinical applications and mechanisms of its action, an efficient method to produce large amounts of active recombinant human CTRP1 is necessary. This study should facilitate basic functional and pharmacological studies of this important protein family.
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Hui X, Schneider E, Ali M, Schwartz D, Canner J, Leeper W, Efron D, Haut E, Velopulos C, Pawlik T, Haider A. Worse Outcomes Among Uninsured General Surgery Patients: Does the Need for an Emergency Operation Explain These Disparities? J Surg Res 2014. [DOI: 10.1016/j.jss.2013.11.581] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Canner J, Haider A, Hui X, Selvarajah S, Wang H, Efron D, Haut E, Velopulos C, Schwartz D, Chi A, Schneider E. U.S. Emergency Department Visits for Injuries Due to Fireworks, 2006-2010: Have Skyrocketing Sales Led to an Explosion of Injuries? J Surg Res 2014. [DOI: 10.1016/j.jss.2013.11.841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Lwin A, Velopulos C, Hui X, Cerullo M, Ali M, Schneider E, Kironji A, Britton B, Haut E, Efron D, Haider A. Economics of an Emergency Room Visit After a Minor Injury: The Cost of Not Being Insured. J Surg Res 2014. [DOI: 10.1016/j.jss.2013.11.847] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Sun J, Ying W, Liu D, Hui X, Yu Y, Wang J, Wang X. Clinical and genetic features of 5 Chinese patients with X-linked lymphoproliferative syndrome. Scand J Immunol 2014; 78:463-7. [PMID: 23944711 DOI: 10.1111/sji.12103] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2013] [Accepted: 08/04/2013] [Indexed: 11/28/2022]
Abstract
In this study, we report the clinical and genetic features of Chinese patients with X-linked lymphoproliferative syndrome (XLP). Male patients with fulminant infectious mononucleosis (FIM), Epstein-Barr virus (EBV)-associated hemophagocytic lymphohistiocytosis (HLH) or persistent EBV viremia were enrolled in this study. Direct sequencing was used to detect SH2D1A/XIAP gene mutations. The patients' clinical features were assessed by retrieval of data from medical records. Twenty-one male patients with FIM, EBV-associated HLH or persistent EBV viremia were evaluated. Four patients had SH2D1A mutations, and one patient had an XIAP mutation. All five of these patients had symptoms of HLH and EBV infection. Among the five patients, the youngest one was only 1 month old at onset. One patient exhibited hypogammaglobulinemia. Of four patients evaluated for immunological function, all exhibited reduced CD4/CD8 ratios. Three patients had rapid disease progression and died. One patient received haematopoietic stem cell transplantation and is well. The overall clinical phenotypes of Chinese patients with XLP matched previous reports. For patients with severe EBV-associated HLH, our results indicate the need to examine the possibility of XLP.
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Pal A, Hashmi Z, Zafar S, Hui X, Scott V, Efron D, Haut E, Schneider E, Haider A. Burden of Comorbidities in Geriatric Trauma: Should the Elderly Continue to be Excluded From Risk-Adjusted Trauma Mortality Analyses? J Surg Res 2013. [DOI: 10.1016/j.jss.2012.10.539] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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Liu XJ, Xu Y, Hui X, Lu ZP, Li F, Chen GL, Lu J, Liu CT. Metallic liquids and glasses: atomic order and global packing. PHYSICAL REVIEW LETTERS 2010; 105:155501. [PMID: 21230918 DOI: 10.1103/physrevlett.105.155501] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2010] [Revised: 07/16/2010] [Indexed: 05/30/2023]
Abstract
In this Letter, we have revealed the common structural behavior of metallic glasses through scrutinizing the evolution of pair distribution functions from metallic liquids to glasses and statistically analyzing pair distribution functions of 64 metallic glasses. It is found that the complex atomic configuration in metallic glasses can be interpreted globally as a combination of the spherical-periodic order and local translational symmetry. The implications of our study suggest that the glass transition could be visualized mainly as a process involving in local translational symmetry increased from the liquid to glassy states.
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Sun SF, Pan QZ, Hui X, Zhang BL, Wu HM, Li H, Xu W, Zhang Q, Li JY, Deng XM, Chen JW, Lian ZX, Li N. Stronger in vitro phagocytosis by monocytes-macrophages is indicative of greater pathogen clearance and antibody levels in vivo. Poult Sci 2008; 87:1725-33. [PMID: 18753439 DOI: 10.3382/ps.2007-00202] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
Abstract
Monocytes-macrophages are crucial players in specific and nonspecific immune responses to protect organisms from invasion of bacteria or viruses. In this study, monocytes in circulation from 2 lines of Silky and Starbro chickens with different disease resistance were separated and cultured in vitro. After identification with acridine orange (AO), Giemsa staining, and CD14 immunostaining, monocytes-macrophages were used for adherence and phagocytosis test. The overall percentages of adherence of Silky monocytes was 1.5 times greater than that of Starbro (P < 0.01), which were 26.85% +/- 8.24% and 18.34% +/- 8.15%, respectively (mean +/- SD). The monocytes-macrophages phagocytic index, phagocytic product, and percentage of phagocytosis in Silkies were greater than in Star-bros, respectively. The difference of phagocytic index was significant (P < 0.05), that is, 3.70 +/- 1.75 and 1.97 +/- 0.31, respectively (mean +/- SD). Then, 20 Silkies were divided into 2 groups according to phagocytic index: high phagocytic index (HPI) group and low phagocytic index (LPI) group, to study the relationship between phagocytic activity in vitro and pathogen clearance. After being challenged against Salmonella Pullorum C79-13, the Silky birds with HPI produced a 3-fold greater level of specific antibodies compared with those with LPI (P < 0.01), 50.21 +/- 6.67 and 16.85 +/- 4.52, respectively (mean +/- SD). In contrast to LPI birds, HPI birds shed less Salmonella Pullorum bacteria (P < 0.05), that is, 168.98 x 10(8) +/- 294.74 x 10(8) compared to 385.40 x 10(8) +/- 399.94 x 10(8) (mean +/- SD), and the shedding peak of Salmonella Pullorum in the test span appeared 4 d earlier. These results indicated that phagocytosis of monocytes-macrophages had strong effects on antibody titer and bacteria shedding postchallenge, which could be used to predict the disease resistance in animals.
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Zhao L, Li T, Wang Y, Pan Y, Ning H, Hui X, Xie H, Wang J, Han Y, Liu Z, Fan D. Elevated plasma osteopontin level is predictive of cirrhosis in patients with hepatitis B infection. Int J Clin Pract 2008; 62:1056-62. [PMID: 17537188 DOI: 10.1111/j.1742-1241.2007.01368.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Osteopontin (OPN) was shown to play an important role in the pathogenesis of various inflammatory and fibrotic processes and elevated in fibrotic liver of mouse model. However, the significance of OPN in hepatitis B virus (HBV)-induced liver cirrhosis (LC) remains unclear and is therefore evaluated in this study. METHODS Thirty-nine patients with HBV-induced LC, 30 patients with HBV infection but without cirrhosis, 11 patients with HBV-related hepatocellular carcinoma (HCC) and 14 additional healthy controls were enrolled in this study. Plasma levels of OPN were measured with enzyme-linked immunosorbent assay and the relationship between OPN and clinical parameters was evaluated. RESULTS When compared to HBV infection group (median 2.16 ng/ml), plasma levels of OPN were significantly increased in cirrhosis (4.52 ng/ml, p < 0.001) and cancer group (13.38 ng/ml, p < 0.001). The OPN level was correlated with the severity of liver damage according to Child-Pugh classification (p = 0.003). It showed at least comparable sensitivity and specificity to predict cirrhosis as aspartate aminotransferase to platelet ratio index, a previously established non-invasive serum marker of cirrhosis. CONCLUSIONS These data suggest that OPN could be used to evaluate the existence of LC, as OPN has previously been reported to be increased in the HCC; this unique feature makes OPN a promising candidate for prediction biomarker in the long-time surveillance of patients with HBV infection to evaluate the risk of cirrhosis and cancer.
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Zhai H, Chan HP, Hui X, Maibach HI. Skin decontamination of glyphosate from human skin in vitro. Food Chem Toxicol 2008; 46:2258-60. [PMID: 18407393 DOI: 10.1016/j.fct.2008.03.001] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2007] [Revised: 02/09/2008] [Accepted: 03/03/2008] [Indexed: 11/28/2022]
Abstract
This study compared three model decontaminant solutions (tap water, isotonic saline, and hypertonic saline) for their ability to remove a model herbicide (glyphosate) from an in vitro human skin model. Human cadaver skin was dosed (approximately 375microg) of [14C]-glyphosate on 3cm2 per skin. After each exposure time (1, 3, and 30min post-dosing, respectively), the surface skin was washed three times (4ml per time) with each solution. After washing, the skin was stripped twice with tape discs. Lastly, the wash solutions, strippings, receptor fluid, and remainder of skin were liquid scintillation analyzer counted to determine the amount of glyphosate. There were no statistical differences among these groups at any time points. The total mass balance recovery at three time exposure points was between 94.8% and 102.4%. The wash off rates (glyphosate in wash solutions) at three different exposure times is 79-101.2%. Thus the three tested decontaminants possess similar effectiveness in removing glyphosate from skin. This in vitro model is not only economic and rapid, but also provides quantitative data that may aid screening for optimal decontaminants.
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Hui X, Shanjiong S, Jiabi Z. NifL, an antagonistic regulator of NifA interacting with NifA. ACTA ACUST UNITED AC 2008; 41:303-8. [PMID: 18425637 DOI: 10.1007/bf02895106] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/1997] [Indexed: 11/30/2022]
Abstract
Nitrogen fixation (nif) genes of diazotrophic enteric bacteria,Enterobacter cloacae orKlebsiella pneumoniae, are regulated bynif LA operon, in which thenif A product, NifA positively regulatesnif gene transcription, whereas the nifL product NifL represses it under oxygen or in excess of fixed nitrogen. Two-hybrid system was used to detect the possible interaction between NifA and NifL. The preliminary results illustrate that NifL does interact with NifA. The interaction between NifL and NtrC has also been shown.
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Hui X, Hornby SB, Wester RC, Barbadillo S, Appa Y, Maibach H. In vitro human nail penetration and kinetics of panthenol. Int J Cosmet Sci 2007; 29:277-82. [DOI: 10.1111/j.1467-2494.2007.00373.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Zhai H, Barbadillo S, Hui X, Maibach HI. In vitro model for decontamination of human skin: Formaldehyde. Food Chem Toxicol 2007; 45:618-21. [PMID: 17123683 DOI: 10.1016/j.fct.2006.10.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2006] [Revised: 10/10/2006] [Accepted: 10/17/2006] [Indexed: 10/24/2022]
Abstract
Decontamination of a chemical from skin is often an emergency measure. This study utilized an in vitro model to compare the decontamination capacity of three model decontaminant solutions (tap water, isotonic saline, and hypertonic saline). Human cadaver skin was dosed (approximately 0.25 microg on 3 cm(2) per skin) with radio-labeled [(14)C]-formaldehyde. After a defined exposure time (1, 3, and 30 min post-dosing, respectively), the surface skin was washed three times (4ml per time) with each solution. After washing, the skin was stripped with tape discs twice. Lastly, the wash solutions, strippings, receptor fluid, and remainder of skin were liquid scintillation analyzer counted to determine the amounts of formaldehyde. Additionally, an evaporation test at different exposure times (1min, 3min, 15min, 30min, and 60min, respectively) was conducted to monitor formaldehyde % evaporation. There were no statistical differences among these groups except isotonic saline, at 3min post-exposure (in wash solutions), showed a significantly difference (p<0.05) when compared to tap water. Formaldehyde % evaporation increased linearly with extending application times, and were 7.7%, 13.6%, 19.7%, 24.4%, and 35.9% (1min, 3min, 15min, 30min, and 60min, respectively). This data suggests that isotonic saline may be effective in removing formaldehyde from skin. However, results from this model need validation in vivo. The model may provide a facile and robust method of accelerating knowledge of decontamination mechanism and lead to enhanced efficacy.
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Qureshi F, Cetin S, Drain P, Murray S, Hui X, Li J, Boyle P, Ford H, Hackam D. Interferon gamma inhibits inter-enterocyte communication by reducing connexin 43 phosphorylation. J Surg Res 2004. [DOI: 10.1016/j.jss.2004.07.064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Hui X, Anigbogu A, Singh P, Xiong G, Poblete N, Liu P, Maibach HI. Pharmacokinetic and local tissue disposition of [14C]sodium diclofenac following iontophoresis and systemic administration in rabbits. J Pharm Sci 2001; 90:1269-76. [PMID: 11745779 DOI: 10.1002/jps.1079] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
The systemic pharmacokinetics and local drug distribution of sodium diclofenac in skin and underlying tissues was studied. Iontophoresis facilitated local and systemic delivery of diclofenac sodium compared with passive diffusion. The maximum plasma concentration of sodium diclofenac was achieved within 1 h of iontophoresis, and the delivery was proportional to applied current density (371 +/- 141 and 132 +/- 62 microg/L at 0.5 and 0.2 mA/cm(2), respectively). The in vivo delivery efficiency for diclofenac in rabbit was 0.15 mg/mA.h. The concentrations of sodium diclofenac in the skin, subcutaneous tissue, and muscle beneath the drug application site (cathode) were significantly greater than plasma concentrations and concentrations of drug in similar tissues at the untreated sites. The results thus suggest that the cutaneous microvasculature is not always a perfect "sink" and that transdermal iontophoresis facilitated the direct penetration of diclofenac sodium to deeper tissues. No skin irritation was observed up to 0.5 mA/cm(2) current density and 7 mg/mL sodium diclofenac concentration.
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Vohra BP, Hui X. Taurine protects against carbon tetrachloride toxicity in the cultured neurons and in vivo. Arch Physiol Biochem 2001; 109:90-4. [PMID: 11471076 DOI: 10.1076/apab.109.1.90.4287] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Carbon tetrachloride (CCl4) has been found to induce cellular damage by generating oxygen free radicals. A study was carried out to investigate the effects of taurine (extracted from Pegasus laternarius Cuvier) on CCl4 intoxicated cultured neurons. CCl4 application (0.4 mmol x l(-1), 0.8 mmol x l( -1), 1.2 mmol x l (-1) and 1.6 mmol x l(-1 )) increased the lipid peroxidation product and decreased glutathione peroxidase (GPx) activity significantly in a concentration dependent manner. Pretreatment of cultures with taurine (10 micromol x l(-1), 30 micromol x l(-1) and 60 micromol x l(-1)) prevented the loss of GPx activity and lipid peroxidation. The effects of three different dosages of taurine (10 mg/kg body wt., 20 mg/kg body wt. and 40 mg/ kg body wt.) for 45 days on the activities of superoxide dismutase and glutathione peroxidase were examined in the cerebrum, cerebellum and medulla of normal and CCl4 treated mice. Treatment of mice with taurine provided protection against CCl4 toxicity as was evident by lipid peroxide status. Taurine was not so successful at inducing the activity of SOD in normal animals except in the medulla where it could increase the activity of SOD (p < 0.05). Taurine induces the GPx activity in a dose dependent manner in all regions of the brain studied. Also in the CCl4 poisoned mice taurine could augment the status of GPx activity in a dose dependent manner. Hence it is concluded that taurine can protects neurons from the oxidative stress induced by CCl4.
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Poet TS, Corley RA, Thrall KD, Edwards JA, Tanojo H, Weitz KK, Hui X, Maibach HI, Wester RC. Assessment of the percutaneous absorption of trichloroethylene in rats and humans using MS/MS real-time breath analysis and physiologically based pharmacokinetic modeling. Toxicol Sci 2000; 56:61-72. [PMID: 10869454 DOI: 10.1093/toxsci/56.1.61] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The development and validation of noninvasive techniques for estimating the dermal bioavailability of solvents in contaminated soil and water can facilitate the overall understanding of human health risk. To assess the dermal bioavailability of trichloroethylene (TCE), exhaled breath was monitored in real time using an ion trap mass spectrometer (MS/MS) to track the uptake and elimination of TCE from dermal exposures in rats and humans. A physiologically based pharmacokinetic (PBPK) model was used to estimate total bioavailability. Male F344 rats were exposed to TCE in water or soil under occluded or nonoccluded conditions by applying a patch to a clipper-shaved area of the back. Rats were placed in off-gassing chambers and chamber air TCE concentration was quantified for 3-5 h postdosing using the MS/MS. Human volunteers were exposed either by whole-hand immersion or by attaching patches containing TCE in soil or water on each forearm. Volunteers were provided breathing air via a face mask to eliminate inhalation exposure, and exhaled breath was analyzed using the MS/MS. The total TCE absorbed and the dermal permeability coefficient (K(P)) were estimated for each individual by optimization of the PBPK model to the exhaled breath data and the changing media and/or dermal patch concentrations. Rat skin was significantly more permeable than human skin. Estimates for K(P) in a water matrix were 0.31 +/- 0.01 cm/h and 0.015 +/- 0.003 cm/h in rats and humans, respectively. K(P) estimates were more than three times higher from water than soil matrices in both species. K(P) values calculated using the standard Fick's Law equation were strongly affected by exposure length and volatilization of TCE. In comparison, K(P) values estimated using noninvasive real-time breath analysis coupled with the PBPK model were consistent, regardless of volatilization, exposure concentration, or duration.
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Thrall KD, Poet TS, Corley RA, Tanojo H, Edwards JA, Weitz KK, Hui X, Maibach HI, Wester RC. A real-time in-vivo method for studying the percutaneous absorption of volatile chemicals. INTERNATIONAL JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HEALTH 2000; 6:96-103. [PMID: 10828137 DOI: 10.1179/oeh.2000.6.2.96] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Realistic estimates of percutaneous absorption following exposures to solvents in the workplace, or through contaminated soil and water, are critical to understanding human health risks. A method was developed to determine dermal uptake of solvents under non-steady-state conditions using real-time breath analysis in rats, monkeys, and humans. The exhaled breath was analyzed using an ion-trap mass spectrometer, which can quantitate chemicals in the exhaled breath stream in the 1-5 ppb range. The resulting data were evaluated using physiologically-based pharmacokinetic (PBPK) models to estimate dermal permeability constants (Kp) under various exposure conditions. The effects of exposure matrix (soil versus water), occlusion versus non-occlusion, and species differences on the absorption of methyl chloroform, trichloroethylene, and benzene were compared. Exposure concentrations were analyzed before and at 0.5-hour intervals throughout the exposures. The percentage of each chemical absorbed and the corresponding Kp were estimated by optimization of the PBPK model to the medium concentration and the exhaled-breath data. The method was found to be sufficiently sensitive for animal and human dermal studies at low exposure concentrations over small body surface areas, for short periods, using non-steady-state exposure conditions.
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Poet TS, Thrall KD, Corley RA, Hui X, Edwards JA, Weitz KK, Maibach HI, Wester RC. Utility of real time breath analysis and physiologically based pharmacokinetic modeling to determine the percutaneous absorption of methyl chloroform in rats and humans. Toxicol Sci 2000; 54:42-51. [PMID: 10746930 DOI: 10.1093/toxsci/54.1.42] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Due to the large surface area of the skin, percutaneous absorption has the potential to contribute significantly to the total bioavailability of some compounds. Breath elimination data, acquired in real-time using a novel MS/MS system, was assessed using a PBPK model with a dermal compartment to determine the percutaneous absorption of methyl chloroform (MC) in rats and humans from exposures to MC in non-occluded soil or occluded water matrices. Rats were exposed to MC using a dermal exposure cell attached to a clipper-shaved area on their back. The soil exposure cell was covered with a charcoal patch to capture volatilized MC and prevent contamination of exhaled breath. This technique allowed the determination of MC dermal absorption kinetics under realistic, non-occluded conditions. Human exposures were conducted by immersing one hand in 0.1% MC in water, or 0.75% MC in soil. The dermal PBPK model was used to estimate skin permeability (Kp) based on the fit of the exhaled breath data. Rat skin K(p)s were estimated to be 0.25 and 0.15 cm/h for MC in water and soil matrices, respectively. In comparison, human permeability coefficients for water matrix exposures were 40-fold lower at 0.006 cm/h. Due to evaporation and differences in apparent Kp, nearly twice as much MC was absorbed from the occluded water (61.3%) compared to the non-occluded soil (32.5%) system in the rat. The PBPK model was used to simulate dermal exposures to MC-contaminated water and soil in children and adults using worst-case EPA default assumptions. The simulations indicate that neither children nor adults will absorb significant amounts of MC from non-occluded exposures, independent of the length of exposure. The results from these simulations reiterate the importance of conducting dermal exposures under realistic conditions.
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Abstract
Taurine was extracted from Pegasus laternarius Cuvier to study its effects on learning and memory in mice. Mice were treated with different doses of taurine (10 mg/kg, 20 mg/kg, 40 mg/kg). The mice were treated with various chemical agents (pentobarbital, cycloheximide, sodium nitrite, alcohol) to disrupt the normal memory process. We measured the effect of taurine on step-down latency (SDL) and escape latency (EL) in a passive avoidance task after 10 or 30 days. Treatment with taurine alone did not change either SDL or EL. Taurine protected mice from the memory disruption induced by alcohol, pentobarbital, sodium nitrite, and cycloheximide but had no obvious effect on motor coordination, exploratory activity, or locomotor activity as measured using the rota-rod test and the hole board test. We conclude that taurine can be effective in attenuating the amnesia produced by alcohol, pentobarbital, cycloheximide, and sodium nitrite without compromising the behavioral aspects of the animals tested.
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Buchholz BA, Fultz E, Haack KW, Vogel JS, Gilman SD, Gee SJ, Hammock BD, Hui X, Wester RC, Maibach HI. HPLC-accelerator MS measurement of atrazine metabolites in human urine after dermal exposure. Anal Chem 1999; 71:3519-25. [PMID: 10464479 DOI: 10.1021/ac990152g] [Citation(s) in RCA: 80] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Metabolites of atrazine were measured in human urine after dermal exposure using HPLC to separate and identify metabolites and accelerator mass spectrometry (AMS) to quantify them. Ring-labeled [14C]atrazine was applied for 24 h with a dermal patch to human volunteers at low (0.167 mg, 6.45 muCi) and high (1.98 mg, 24.7 muCi) doses. Urine was collected for 7 days. The urine was centrifuged to remove solids, and the supernatant was measured by liquid scintillation counting prior to injection on the HPLC to ensure that < 0.17 Bq (4.5 pCi) was injected on the column. A reversed-phase gradient of 0.1% acetic acid in water and 0.1% acetic acid in acetonitrile became less polar with increasing time and separated the parent compound and major atrazine metabolites over 31 min on an octadecylsilane column. Peaks were identified by coelution with known standards. Elution fractions were collected in 1-min increments; half of each fraction was analyzed by AMS to obtain limits of quantitation of 14 amol. Mercapturate metabolites of atrazine and dealkylated atrazine dominated the early metabolic time points, accounting for approximately 90% of the 14C in the urine. No parent compound was detected. The excreted atrazine metabolites became more polar with increasing time, and an unidentified polar metabolite that was present in all samples became as prevalent as any of the known ring metabolites several days after the dose was delivered. Knowledge of metabolite dynamics is crucial to developing useful assays for monitoring atrazine exposure in agricultural workers.
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Wester RC, Hui X, Landry T, Maibach HI. In vivo skin decontamination of methylene bisphenyl isocyanate (MDI): soap and water ineffective compared to polypropylene glycol, polyglycol-based cleanser, and corn oil. Toxicol Sci 1999; 48:1-4. [PMID: 10330677 DOI: 10.1093/oxfordjournals.toxsci.a034663] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
In the home and workplace, decontamination of a chemical from skin is traditionally done with a soap-and-water wash, although some workplaces may have emergency showers. It has been assumed that these procedures are effective, yet workplace illness and even death occur from chemical contamination. Water, or soap and water, may not be the most effective means of skin decontamination, particularly for fat-soluble materials. This study was undertaken to help determine whether there are more effective means of removing methylene bisphenyl isocyanate (MDI), a potent contact sensitizer, from the skin. MDI is an industrial chemical for which skin decontamination, using traditional soap and water and nontraditional polypropylene glycol, a polyglycol-based cleanser (PG-C), and corn oil were all tried in vivo on the rhesus monkey, over 8 h. Water, alone and with soap (5% and 50% soap), were partially effective in the first h after exposure, removing 51-69% of the applied dose. However, decontamination fell to 40-52% at 4 h and 29-46% by 8 h. Thus, the majority of MDI was not removed by the traditional soap-and-water wash; skin tape stripping after washing confirmed that MDI was still on the skin. In contrast, polypropylene glycol, PG-C, and corn oil all removed 68-86% of the MDI in the first h, 74-79% at 4 h, and 72-86% at 8 h. Statistically, polypropylene glycol, PG-C, and corn oil were all better (p < 0.05) than soap and water at 4 and 8 h after dose application. These results indicate that a traditional soap-and-water wash and the emergency water shower are relatively ineffective at removing MDI from the skin. More effective decontamination procedures, as shown here, are available. These procedures are consistent with the partial miscibility of MDI in corn oil and polyglycols.
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Hui X, Hewitt PG, Poblete N, Maibach HI, Shainhouse JZ, Wester RC. In vivo bioavailability and metabolism of topical diclofenac lotion in human volunteers. Pharm Res 1998; 15:1589-95. [PMID: 9794502 DOI: 10.1023/a:1011911302005] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
PURPOSE The primary objective of this study was to determine the rate and extent of transdermal absorption for systemic delivery of diclofenac from Pennsaid (Dimethaid Research, Inc.) topical lotion into the systemic circulation after the lotion was applied to human volunteers, in an open treatment, non-blinded, non-vehicle controlled study. In addition, the in vivo metabolism of this topical diclofenac lotion has also been studied. METHODS Human volunteers were dosed with topical [14C]-diclofenac sodium 1.5% lotion on the knee for 24 h. Sequential time blood and urine samples were taken to determine pharmacokinetics, bioavailability and metabolism. RESULTS Topical absorption was 6.6% of applied dose. Peak plasma 14C occurred at 30 h after dosing, and peak urinary 14C excretion was at 24-48 h. The urinary 14C excretion pattern exhibits more elimination towards 24 h and beyond, as opposed to early urinary 14C excretion. This suggests a continuous delivery of [14C]-diclofenac sodium from the lotion into and through skin which only ceased when the dosing site was washed. Skin surface residue at 24 h was 26 +/- 9.5% dose (remainder assumed lost to clothing and bedding). Extraction of metabolites from urine amounted to 7.4-22.7% in untreated urine, suggesting substantial diclofenac metabolism to more water soluble metabolites, probably conjugates, which could not be extracted by the method employed. Two Dimensional TLC analysis of untreated urine showed minimal or no diclofenac, again emphasizing the extensive in vivo metabolism of this drug. Treatment of the same urine samples with the enzymes sulfatase and beta-glucuronidase showed a substantial increase in the extractable material. Three spots were consistently present in each sample run, namely diclofenac, 3'hydroxy diclofenac and an intermediate polar metabolite (probably a hydroxylated metabolite). Therefore, there was significant sulfation and glucuronidation of both diclofenac and numerous hydroxy metabolites of diclofenac, but many of the metabolites/conjugates remain unidentified. CONCLUSIONS; There was a continuous delivery of diclofenac sodium from the lotion into and through the skin, which ceased after the dosing site was washed. The majority of the material excreted in the urine were conjugates of hydroxylated metabolites, and not the parent chemical, although further identification is required.
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