[Hinokiol regulates the cell cycle and apoptosis of nasopharyngeal carcinoma CNE1 cells via Hippo-YAP signaling pathway].

Objective: To explore the effects of hinokiol on the cell cyle and apoptosis of CNE1 nasopharyngeal carcinoma cells and the relevant molecular mechanism. Methods: The CNE1 cells were cultured in vitro and incubated with different concentrations of honokiol, and the cells were divided into blank control group, 10 µmol/L, 20 µmol/L and 40 µmol/L hinokiol treatment groups, and 10 µg/ml cisplatin group. Cell viability was determined by methylthiazolyldiphenyl- tetrazolium bromide (MTT) method, the cell cycle distribution was detected by flow cytometry, mitochondrial membrane potential was detected by mitochondrial membrane potential test kit, apoptosis was detected by terminal deoxynucleotidyl transferase mediated dUTP nick end labeling (TUNEL) method, and the proteins expression of proliferating cell nuclear antigen (PCNA) and G1/S specific cyclin D1 (cyclin D1) were detected by immunoblotting. RNA-Seq was conducted in the hinokiol-treated cells. The mRNA expression of yes-associated protein delta (YAP) was detected by quantitative reverse transcription polymerase chain reaction (RT-qPCR). The proteins expression of phosphor-YAP (p-YAP) and nuclear YAP were detected by immunoblotting, the nuclear distribution of YAP protein was detected by immunofluorescence in the cells with or without treated with the mammalian STE20-like kinase 1/2 (MST1/2) inhibitor (XMU-MP-1), hinokiol, and XMU-MP-1+hinokiol. Statistical analysis of the data was conducted using GraphPad Prism 8.0 software. Resluts Compared with the control group, the cell viablity of CNE1 cells, the levels of mitochondrial membrane potential, the proteins expression of PCNA and cyclin D1 in hinokiol treatment groups were markedly decreased (all P values<0.05), while the proportion of G0/G1 phase cells and the ratio of TUNEL-positive cells were significantly increased (both P values<0.05). Transcriptome analysis showed that differential genes were mainly enriched in Wnt signaling pathway, tumor necrosis factor pathway, and Hippo signaling pathway. The mRNA level of YAP and the protein expression of YAP in the nucleus were decreased and the level of p-YAP protein was increased in cells treated with hinokiol, which were significantly different from control group (all P values<0.05). Compared with the hinokiol group, XMU-MP-1+hinokiol groups showed the decrease of p-YAP protein expression (1.157±0.076 vs 0.479±0.038, t=37.120, P<0.05), the increase of YAP protein expression in the nucleus (0.143±0.012 vs 0.425±0.031, t=29.181, P<0.05), the reduced proportion of cells in G0/G1 phase [(72.494±3.309)% vs (58.747±2.865)%, t=17.265, P<0.05], and the decrease of apoptosis ratio [(53.158±3.376)% vs (29.621±2.713)%, t=28.584, P<0.05]. Conclusion: Hinokiol can arrest the cell cycle and induce the cell apoptosis of CNE1 cells via Hippo/YAP signaling pathway.

[The effect of the AIM2 inflammasome in noise-induced cognitive dysfunction in rats].

Objective: To explore the effect of the absent in melanoma 2 (AIM2) -mediated neuroinflammation in noise-induced cognitive dysfunction in rats. Methods: In April 2023, sixteen male Wistar rats were randomly divided into control group and noise group, with 8 rats in each group. The rats in the noise group were placed in 50 cm×50 cm×40 cm transparent boxes and exposed to 100 dB (A) white noise with a sound pressure level of 100 dB (A) (4 h/d for 30 d) . At the same time, rats in the control group were kept in similar boxes with environmental noise less than 60 dB (A) . After 30 days of noise exposure, the Morris water maze experiment was applied to test the learning and memory abilities of the rats; the pathological morphology of hippocampal tissues was observed by Hematoxylin-Eosin (HE) staining. Western blot was used to detect the protein expression levels of AIM2, cysteinyl aspartate specific proteinase-1 (caspase-1) , apoptosis-associated speck-like protein (ASC) , interleukin-1ß (IL-1ß) , IL-18, ionic calcium-binding articulation molecule-1 (Iba-1) , and glial fibrillary acidic protein (GFAP) . The expression of both Iba-1 and GFAP in hippocampal tissue was assessed by immunohistochemical staining. The co-localization of AIM2 with Iba-1 or GFAP was determined by immunofluorescence double staining. Results: Compared with the control group, the escape latency of rats in the noise group was increased by 16.29 s, 17.71 s, and 20.26 s on days 3, 4, and 5, respectively. On day 6, the noise-exposed rats spent shorter time in the target quadrant and had fewer times in crossing the platform[ (7.25±2.27) s and (1.13±0.64) times] than the control group[ (15.64±3.99) s and (4.25±2.12) times] (P<0.05) . After noise exposure, hippocampal neurons of rats displayed marked nuclear hyperchromatic and pyknosis phenomenon. The noise-exposed rats had higher numbers of both microglia and astrocytes (27.00±2.65 and 43.33±5.51) in the DG area of the hippocampus relative to the control group (14.67±3.06 and 20.00±4.58) (P<0.05) . Moreover, the glial cells in the noise group had larger cell cytosol with more and thicker branches. The protein expression levels of inflammatory cytokines Cleaved-IL-1ß and Cleaved-IL-18 in the hippocampus of rats in the noise group (1.55±0.19 and 1.74±0.12) were significantly higher than the control group (1.00±0.11 and 1.00±0.13) (P<0.05) . After noise exposure, the protein expression levels of AIM2, Cleaved-Caspase-1 and ASC (1.19±0.09, 1.34±0.07 and 1.14±0.01) were higher than the control group (1.00±0.07, 1.00±0.14 and 1.00±0.06) and differences between the two groups were statistically significant (P<0.05) . A significant increase in the number of cells co-localizing AIM2 with Iba-1 or GFAP in the noise group (28.67±4.04 and 40.67±5.13) compared with the control group (15.67±4.04 and 17.67±3.79) , and statistically significant differences were observed between the two groups (P<0.05) . Conclusion: Noise exposure may activate the AIM2 inflammasome in hippocampal glial cells of rats, releasing excessive inflammatory cytokines and causing neuroinflammation that damages neurons.

[Morphologic features of fallopian tubal epithelium in pelvic high-grade serous carcinoma].

Objective: To study the pathologic features of fallopian tubal epithelium in patients with pelvic high-grade serous carcinoma (HGSC), to investigate its role in pelvic serous carcinogenesis and to reclassify the primary site of HGSC based on recently proposed criteria. Methods: The fallopian tubes in 58 cases of pelvic HGSC (54 cases of ovarian primary, 3 cases of tubal primary, 1 case of peritoneum) and 25 cases of pelvic non-HGSC (5 cases of ovarian low-grade serous cancer, 9 cases of endometrioid cancer, and 11 cases of clear cell ovary carcinoma) were collected from June 2015 to December 2016, and serially examined under light microscope (SEE-FIM protocol). Immunostaining for p53 and Ki-67 was performed to evaluate the presence of p53 signature, serous tubal intraepithelial lesion (STIL), serous tubal intraepithelial carcinoma (STIC) and invasive carcinoma in these fallopian tubes. Meanwhile, primary site of HGSC based on the recently proposed diagnostic criteria were also reclassified. Results: Among the study group, the frequencies of p53 signature, STIL, STIC and invasive HGSC were 27.6% (16/58), 43.1% (25/58), 36.2% (21/58) and 67.2% (39/58), respectively, while in control group, the proportions were 24.0% (6/25), 0, 0 and 8.0% (2/25), respectively. The continuum of epithelial changes in the process of serous neoplasia including p53 signature, STIL, STIC and invasive carcinoma was identified in 8 cases of pelvic HGSC. The proportions of STIL, STIC and invasive carcinomas in HGSC group were higher than that in non-HGSC group (P<0.01). About 80.0% (20/25) of STIL and 85.7% (18/21) of STIC were present unilaterally. Diagnostically, the study group contained the 17 cases of ovarian HGSC, 40 cases of tubal HGSC, and 1 case of peritoneal HGSC after reclassification of the cancer primary. Conclusions: Continuous changes of tubal epithelium including p53 signature, STIL, STIC and invasive carcinomas are identified in patients with HGSC, supporting the current understanding that the fallopian tube is likely the cellular source of the majority HGSC. STIL and STIC may be specific to pelvic HGSC and may act as a target for future research on the early detection and prevention of this disease. The newly proposed diagnostic criteria for pelvic HGSC will lead us to more accurate classification of cancer primary sites. Correct classification of HGSC may have potential impacts for cancer prevention and improve our understanding of ovarian serous carcinogenesis.

Acute cellular rejection with isolated v-lesions is not associated with more favorable outcomes than vascular rejection with more tubulointerstitial inflammations.

BACKGROUND: The impact of isolated v-lesions on clinical outcome in biopsies with acute cellular rejection (ACR) is unclear. METHODS: Two hundred and sixty-five biopsies showing the highest ACR severity for each patient were recruited and classified into four groups: (i) acute interstitial rejection (AIR) I with minimal tubulointerstitial inflammation (TI), (ii) AIR II with intensive TI, (iii) acute vascular rejection (AVR) I with minimal TI, and (iv) AVR II with intensive TI. RESULTS: The complete reversal rates of AIR I and AIR II groups were marginally higher than AVR I and AVR II groups (p = 0.16). At eight yr of transplantation, the death-censored graft survival (DCGS) rate of AIR I group (93.3%) was significantly higher compared with the AVR I (72.7%) or AVR II (72.9%) group. AVR I group had a similar DCGS rate with AVR II group (72.7% vs. 74.1%), whereas AVR with v1-lesion showed significantly higher graft survival (GS) rate than those with v2-lesion (70.2% vs. 45.5%). The t-lesion of AIR and v-lesion of AVR group were associated with graft loss. CONCLUSION: The extent of TI is non-specifically associated with graft loss in biopsies with AVR; the higher grade v-lesion predicts the lower complete reversal rate and poorer long-term graft survival.

Inflammatory markers in cord blood or maternal serum for early detection of neonatal sepsis-a systemic review and meta-analysis.

OBJECTIVE: To perform a quantitative review of the evidence on the diagnostic value of inflammatory markers in maternal serum or umbilical cord blood for the diagnosis of early-onset neonatal sepsis (EONS). STUDY DESIGN: We searched multiple databases for studies published through March 2013 that evaluated the diagnostic performance of procalcitonin (PCT), C-reactive protein (CRP) and interleukin-6 (IL-6), and leukocyte count (white blood cell, WBC) in either umbilical cord blood or maternal serum for diagnosis of EONS. We summarized test performance characteristics with the use of forest plots, hierarchical summary receiver operating characteristic curves and bivariate random effects models. RESULT: Our search identified 3874 citations, of which 15 studies evaluating 2178 episodes of suspected neonatal infection were included for analysis. IL-6 in cord blood with a pooled-positive likelihood ratio (LR+) of 9.47 (95% confidence interval: 3.86 to 23.3), PCT in cord blood with a LR+ of 5.72 (1.56 to 21.0) and IL-6 in maternal serum with a LR+ of 5.47 (2.10 to 14.2) can be qualified as a valid rule-in test. IL-6 in cord blood with a LR- of 0.10 (0.05 to 0.21) and PCT in cord blood with a LR- of 0.20 (0.12-0.37) can be qualified as a useful rule-out test. Either CRP or WBC was inadequate for diagnosis of EONS. CONCLUSION: For cord blood sample, IL-6 or PCT can be used as reliable rule-in and rule-out tool. For maternal serum, only IL-6 appeared to be sufficient for rule-in diagnosis. An interventional study may be needed to answer whether the addition of these tests will improve the outcome of patients with EONS.

Urinary 1-hydroxypyrene and malondialdehyde in male workers in Chinese restaurants.

OBJECTIVES: To assess internal dose and oxidative stress in male restaurant workers exposed to polycyclic aromatic hydrocarbons (PAHs) from cooking oil fumes (COFs) in Chinese restaurants. METHODS: The study participants included 288 male restaurant workers (171 kitchen and 117 service staff) in Chinese restaurants in Taiwan. Airborne particulate PAHs were measured over 12 h on each of two consecutive work days and then identified using high performance liquid chromatography. Urinary 1-hydroxypyrene (1-OHP) measurements were used to indicate COF exposure, and urinary malondialdehyde (MDA) was adopted as an oxidative stress marker. Multiple regression models were used to assess the relationship between MDA and 1-OHP levels after adjusting for key personal covariates. RESULTS: Summed particulate PAH levels in kitchens (median 23.9 ng/m(3)) were significantly higher than those in dining areas (median 4.9 ng/m(3)). For non-smoking kitchen staff, mean MDA and 1-OHP levels were 344.2 (SD 243.7) and 6.0 (SD 8.0) mumol/mol creatinine, respectively. These levels were significantly higher than those for non-smoking service staff, which were 244.2 (SD 164.4) and 2.4 (SD 4.3) mumol/mol creatinine, respectively. Urinary 1-OHP levels were significantly associated with work in kitchens (p<0.05). Furthermore, urinary MDA levels were significantly associated with urinary 1-OHP levels (p<0.001) and working hours per day (p<0.05). CONCLUSIONS: These findings indicate that urinary 1-OHP and MDA levels reflect occupational exposure to PAHs from COFs and oxidative stress in workers in Chinese restaurants.

Chromium (VI) induced oxidative damage to DNA: increase of urinary 8-hydroxydeoxyguanosine concentrations (8-OHdG) among electroplating workers.

AIMS: To investigate the concentration of urinary 8-hydroxydeoxyguanosine (8-OHdG) among electroplating workers in Taiwan. METHODS: Fifty workers were selected from five chromium (Cr) electroplating plants in central Taiwan. The 20 control subjects were office workers with no previous exposure to Cr. Urinary 8-OHdG concentrations were determined using high performance liquid chromatography with electrochemical detection. RESULTS: Urinary 8-OHdG concentrations among Cr workers (1149.5 pmol/kg/day) were higher than those in the control group (730.2 pmol/kg/day). There was a positive correlation between urinary 8-OHdG concentrations and urinary Cr concentration (r = 0.447, p < 0.01), and urinary 8-OHdG correlated positively with airborne Cr concentration (r = 0.285). Using multiple regression analysis, the factors that affected urinary 8-OHdG concentrations were alcohol, the common cold, and high urinary Cr concentration. There was a high correlation of urinary 8-OHdG with both smoking and drinking, but multiple regression analysis showed that smoking was not a significant factor. Age and gender were also non-significant factors. CONCLUSION: 8-OHdG, which is an indicator of oxidative DNA damage, was a sensitive biomarker for Cr exposure.

Toxic effects of mitomycin-C on cultured ciliary process cells and trabecular meshwork cells.

Mitomycin-C has recently become an adjunct medication for inhibition of fibroblast proliferation in glaucoma filtering procedures. Prolonged postoperative ocular hypotony has been a frequent complication of trabeculectomy with mitomycin-C. In order to characterize the hypotony mechanism, we compared the toxic effects of mitomycin-C on cultured rabbit ciliary process cells and trabecular meshwork cells. The results indicate that mitomycin-C has a more marked effect on ciliary process cells on 3H-thymidine uptake than on trabecular meshwork cells at concentrations ranging from 10(-1) to 10(-5) mg/ml after 3-, 5- and 60-min treatment, respectively. The living cells after mitomycin-C treatment were estimated with MTT assay that was converted tetrazolium dye of living cells only into insoluble purple formazan crystals within mitochondria. In the presence of mitomycin-C for 3, 5, and 60 min, the cellular MTT values in ciliary process cells were more decreased than in trabecular meshwork cells. Depolarization of the trabecular meshwork cells with 50 mM KCl led to an increase in intracellular calcium concentration, whereas application of mitomycin-C at 10(-3) mg/ml resulted in decrease of KCl-induced intracellular calcium increase. Mitomycin-C (10(-3) mg/ml) decreased cAMP concentration in ciliary process cells following 3- and 5-min treatment; however, it did not significantly affect the cellular cAMP concentration after only a 1-min exposure. Mitomycin-induced marked ladder pattern of DNA fragmentation was observed in ciliary process tissues after treatment with 10(-1) mg/ml of mitomycin-C for 3 and 5 min. However, the DNA pattern in trabecular meshwork tissues was not obviously affected by mitomycin-C. These findings from our results indicate that mitomycin-induced ocular hypotony may result from damage to both ciliary process and trabecular meshwork tissues.

Endothelin-induced changes of secondary messengers in cultured corneal endothelial cells.

The effect of endothelins on corneal endothelial cells is not well understood. We have investigated the effects of endothelin-1 (ET-1), endothelin-2 (ET-2) and endothelin-3 (ET-3) on bovine corneal endothelial cellular proliferation and the secondary messenger changes in cells in the presence of ET-1. It was found that the 3H-thymidine uptake was enhanced by ET-1 significantly, whereas ET-2 and ET-3 had no effect. ET-1 remarkably affects the increase of corneal endothelial cells on 3H-thymidine, 3H-leucine, and 3H-uridine uptakes in a dose-dependent manner. The 50% effective concentrations (EC50) for ET-1, as measured by 3H-thymidine uptake, 3H-uridine uptake, and 3H-leucine uptake were 10(-8.78) M, 10(-8.53) M and 10(-8.04) M, respectively. It was found that endothelin-1 increased intracellular calcium concentration by using the method of preloading with Fura-2-AM and assaying with spectrophotometry. The cellular IP1, IP2, and IP3 were also stimulated in the presence of ET-1. Moreover, ET-1 enhanced the basal cellular cAMP and cGMP concentrations in corneal endothelial cells in a dose-dependent manner. Immunofluorescent staining revealed that ET-1 increased the fibronectin protein concentration and changed protein distribution in corneal endothelial cells. These findings indicate that endothelin-1 increases in cell proliferation and biological changes may be involved in changing intracellular calcium mobility, increasing intracellular phosphoinositides, enhancing intracellular cGMP and cAMP accumulation, and fibronectin protein synthesis.

Effects of drugs on cellular proliferation in cultured iris pigment epithelial cells and retinal pigment epithelial cells.

In this study, iris and retinal pigment epithelial cells were cultured from porcine and various drugs including methionine-enkephalin, isoproterenol, dibutyryl cAMP, endothelin-1, dexamethasone and phorbol 12-myristate 13-acetate (PMA) were used to investigate their effects on both cellular proliferation in cultured porcine iris and retinal pigment epithelial cells. Cellular proliferation was estimated with 3H-thymidine uptake. It is indicated that both pigment epithelial cells possess epithelial-like morphology and abundant pigment granules in cells obviously. Following the iris pigment epithelial cells being treated with endothelin-1, the 3H-thymidine uptake in the cells was increased to 126% as compared with the control. However, the cellular proliferation was decreased to 83% when the cells were treated with isoproterenol. In the case of methionine-enkephalin, dibutyryl cAMP, dexamethasone and phorbol 12-myristate 13-acetate (PMA), the thymidine uptake in the iris pigment epithelial cells was not affected by above drugs. In the retinal pigment epithelial cells, the 3H-thymidine uptakes were increased to 145% and 146% when the cells were incubated with methionine-enkephalin, and isoproterenol, respectively. In the presence of dibutyryl cAMP, dexamethasone and phorbol ester (PMA), the cellular proliferation was inhibited to 83%, 73% and 85% respectively. However, endothelin-1 did not affect the cellular proliferation in retinal pigment epithelial cells. These results show that the morphological shapes of iris pigment epithelial cells are similar to retinal pigment epithelial cells. However, the cellular proliferation in both cells may be regulated by distinct mechanisms.

Tentative surgical repair of leaking filtering bleb with amniotic membrane transplantation--a case report.

To repair a traumatic leaking cystic bleb in a 50-year-old male patient who had received multiple glaucoma filtering surgeries with the application of mitomycin-C, an amniotic membrane covered over the leaking bleb and sutured it to the adjacent conjunctiva with 10-0 nylon was done. The anterior chamber gradually formed after the amniotic membrane transplantation (AMT) and intraocular pressure returned to the level before trauma. Three weeks after the operation, the amniotic membrane was removed. No more leakage from the bleb was observed during four months follow-up. However, another bleb revision surgery was performed later to repair recurrent bleb leakage. Although conjunctival advancement or free conjunctival autograft have been reported to repair leaking bleb successfully, the simple primary method of using AMT is still encouraged in repair of a ruptured bleb with tentative maintenance of adequate filtration.

Change of calcium and cAMP concentration by adrenoceptor agents in cultured porcine corneal endothelial cells.

It has been reported that beta-adrenergic receptors are localized in the corneal endothelial cells. In this study, the change of cellular signal transduction, such as intracellular calcium and cAMP, was determined with pure adrenergic agonists and commercial antiglaucoma adrenergic agents. The intracellular calcium of cultured porcine corneal endothelial cells was inhibited by 10 microM isoproterenol and norepinephrine, but enhanced by propranolol and 50 mM KCl. In the case of phenylephrine, calcium mobility did not alter significantly. Verapamil, at 10 microM, decreased intracellular calcium concentration. In the presence of isoproterenol, cellular cAMP concentration increased from 28.8 pmole/mg protein (1 microM) to 42.2 pmole/mg protein (100 microM) compared with control of 6.07 pmole/mg protein. Incubation with commercial adrenergic eye drops, such as betaxolol, caused the cAMP concentration to increase from 21.6 pmole/mg protein (0.0005%) to 39.1 pmole/mg protein (0.05%). Adding commercial levobunolol and timolol into cells caused cellular cAMP to increase from 14.3 pmole/mg protein (0.0005%) to 840.5 pmole/mg protein (0.05%) and from 115.2 pmole/mg protein (0.00025%) to 931.0 pmole/mg protein (0.025%), respectively. However, the preservative, benzalkonium chloride, increased cellular cAMP from 15.4 pmole/mg protein (0.00001 mg/ml) to 1087.4 pmole/mg protein (0.01 mg/ml). It is concluded that the intracellular calcium of corneal endothelium decreases when the cellular adrenergic receptor is activated by agonists. Benzalkonium chloride, due to its preservative in commercial antiglaucoma agents which increases cellular cAMP, may alter corneal endothelial physiology through long-term use.

1,3-butadiene: cancer, mutations, and adducts. Part V: Hemoglobin adducts as biomarkers of 1,3-butadiene exposure and metabolism.

1,3-Butadiene (BD) is an important chemical used largely in the manufacture of synthetic rubber and thermoplastic resins. In addition, it has been identified in cigarette smoke, automobile exhaust, and gasoline vapor. The objective of this research was to develop highly sensitive and specific assays for the detection and quantitation of hemoglobin adducts of three BD metabolites: 1,2-epoxy-3-butene (BDO), 1,2,3,4-diepoxybutane (BDO2), and 1,2-dihydroxy-3,4-epoxybutane (BDO-diol). We have successfully developed an assay for both N-(2-hydroxy-3-butenyl)valine (HBVal) and N-(2,3,4-trihydroxybutyl)valine (THBVal) in hemoglobin. The six adducts measured were the two diastereomers (isomers I and II) of HBVal and the four diastereomers of THBVal (isomers I through IV, which were eluted as three peaks, 1, 2, and 3). HBVal and THBVal were measured in control and exposed B6C3F1 mice and Sprague-Dawley rats (1,000 ppm BD for 13 weeks at 6 hours/day, 5 days/week). In a second set of animal exposures, total THBVal was determined in B6C3F1 female mice (n = 5) exposed to 1,250 ppm BD for 1, 5, or 10 days (6 hours/day, 5 days/week). THBVal adducts were also monitored in occupationally exposed Chinese workers and nonoccupationally exposed U.S. laboratory workers. This study utilized the modified Edman degradation method of Törnqvist and colleagues (1986). Briefly, the samples were subjected to Edman degradation, Centricon-30 ultrafiltration, washing on C18 columns, and acetylation for isomers of THBVal only, followed by gas chromatography-mass spectrometry (GC-MS) quantitation. For the HBVal assay, an authentic internal standard globin alkylated with [2H6]BDO was used; for the THBVal assay, a synthesized external standard, THB[13C5]Val, was used after Edman degradation. The mean +/- SD amounts of total HBVal measured in exposed mice (in pmol/g globin) were 16,560 +/- 3,910 for female mice (n = 4) and 12,400 +/- 2,030 for male mice (n = 5). The corresponding values for rats were 8,690 +/- 930 for female rats (n = 5) and 5,480 +/- 2,880 for male rats (n = 3). The total amount of THBVal (eluted peaks 1, 2, and 3) in male mice (n = 5) was 78,900 +/- 13,700; and in females (n = 2) was 56,100 +/- 100. In male rats (n = 3), the detected value was 9,650 +/- 1,620 and in females (n = 3) the value was 21,600 +/- 6,780. In control male mice (n = 4), the total level of THBVal isomers was approximately 27 pmol/g globin. In a control male rat, total THBVal was approximately 15 pmol/g globin. In the time course study, the amount of THBVal adducts increased linearly with exposure, resulting in values of 4,200 +/- 830, 19,760 +/- 1,780, and 35,940 +/- 3,460 pmol/g globin following 1, 5, or 10 days of exposure to 1,250 ppm BD, respectively. Detection of HBVal in human samples was difficult due to low concentrations of adducts and a high background in the chromatograms. In a pooled sample from 4 individuals, we performed multiple separations with high-pressure liquid chromatography (HPLC) of the derivatized adducts and detected 4.6 pmol/g globin (that is, 2.7 and 1.9 pmol/g globin for isomers I and II, respectively). We measured the amounts of THBVal in both nonoccupationally exposed U.S. laboratory workers and occupationally exposed workers from a polybutadiene plant in China. The mean total amount of THBVal among the U.S. laboratory workers was 36 +/- 23 pmol/g globin for nonsmokers (n = 7) and 40 +/- 9 for smokers (n = 4), compared with a mean total amount of 39 +/- 13 pmol/g globin in a control set of Chinese workers (n = 25). These control values are overestimations of the true values because the amounts of THBVal in globin samples from other unexposed individuals (15 of 51) were below our limit of detection. BD-exposed Chinese workers had a total amount of 88 +/- 59 pmol/g globin THBVal. The difference between smokers and nonsmokers was not significant, whereas the difference between control and exposed Chinese workers was highly significant (p < 0.001).

Biomarkers of exposure and effect as indicators of potential carcinogenic risk arising from in vivo metabolism of ethylene to ethylene oxide.

The purposes of the present study were: (i) to investigate the potential use of several biomarkers as quantitative indicators of the in vivo conversion of ethylene (ET) to ethylene oxide (EO); (ii) to produce molecular dosimetry data that might improve assessment of human risk from exogenous ET exposures. Groups (n = 7/group) of male F344 rats and B6C3F1 mice were exposed by inhalation to 0 and 3000 p. p.m. ET for 1, 2 or 4 weeks (6 h/day, 5 days/week) or to 0, 40, 1000 and 3000 p.p.m. ET for 4 weeks. N:-(2-hydroxyethyl)valine (HEV), N:7-(2-hydroxyethyl) guanine (N7-HEG) and HPRT: mutant frequencies were assessed as potential biomarkers for determining the molecular dose of EO resulting from exogenous ET exposures of rats and mice, compared with background biomarker values. N7-HEG was quantified by gas chromatography coupled with high resolution mass spectrometry (GC-HRMS), HEV was determined by Edman degradation and GC-HRMS and HPRT: mutant frequencies were measured by the T cell cloning assay. N7-HEG accumulated in DNA with repeated exposure of rodents to 3000 p.p.m. ET, reaching steady-state concentrations around 1 week of exposure in most tissues evaluated (brain, liver, lung and spleen). The dose-response curves for N7-HEG and HEV were supralinear in exposed rats and mice, indicating that metabolic activation of ET was saturated at exposures >/=1000 p.p.m. ET. Exposures of mice and rats to 200 p.p.m. EO for 4 weeks (as positive treatment controls) led to significant increases in HPRT: mutant frequencies over background in splenic T cells from exposed rats and mice, however, no significant mutagenic response was observed in the HPRT: gene of ET-exposed animals. Comparisons between the biomarker data for both unexposed and ET-exposed animals, the dose-response curves for the same biomarkers in EO-exposed rats and mice and the results of the rodent carcinogenicity studies of ET and EO suggest that too little EO arises from exogenous ET exposure to produce a significant mutagenic response or a carcinogenic response under standard bioassay conditions.

Molecular dosimetry of endogenous and ethylene oxide-induced N7-(2-hydroxyethyl) guanine formation in tissues of rodents.

The formation of N7-(2-hydroxyethyl)guanine (7-HEG) in DNA was investigated previously in target and non-target tissues of F-344 rats and B6C3F1 mice exposed to >/=ISOdia>/=10 p.p.m. concentrations of ethylene oxide (EO) using fluorescence-linked high-performance liquid chromatography [V.E. Walker et al. (1992) Cancer Res., 52, 4238-4334]. In order to study the dose-responses for 7-HEG at lower exposures, a highly sensitive and specific gas chromatography coupled with high-resolution mass spectrometry (GC-HRMS) assay was developed. DNA was extracted from liver, brain, lung and spleen of B6C3F1 mice and F-344 rats exposed to 0, 3, 10, 33 or 100 p.p.m. EO for 4 weeks (6 h/day, 5 days/week). Analysis of DNA from control rodents showed that endogenous 7-HEG varied from 0.2 +/- 0.1 to 0.3 +/- 0.2 pmol/micromol guanine in tissues of rats and mice. 7-HEG exhibited tissue- and species-specific dose-response relationships in EO-exposed animals. Linear dose-response relationships were evident in mouse liver, brain and spleen at exposures between 3 and 100 p.p.m. Mouse lung exhibited a slightly sublinear response between 33 and 100 p.p.m. EO. The relationships were linear in liver and spleen of rats between 3 and 100 p.p.m. EO, but were slightly sublinear in brain and lung between 33 and 100 p.p.m. EO. The number of 7-HEG adducts present in rats exposed to 3 p.p.m. EO was 5.3-12.5 times higher than endogenous 7-HEG in unexposed controls. In contrast, mice exposed to 3 p.p.m. EO only had 1.3- to 2.5-fold greater numbers of 7-HEG adducts. The factors driving the exposure-response relationships are also likely to affect carcinogenic and mutagenic responses of rodents to EO. Likewise, a better understanding of the relationships between 7-HEG derived from low exposures to EO and endogenously formed 7-HEG may be important for the accurate extrapolation of risk to humans.

A gas chromatography/electron capture/negative chemical ionization high-resolution mass spectrometry method for analysis of endogenous and exogenous N7-(2-hydroxyethyl)guanine in rodents and its potential for human biological monitoring.

A gas chromatography/electron capture/negative chemical ionization high-resolution mass spectrometry (GC/EC/NCI-HRMS) method was developed for quantitating N7-(2-hydroxyethyl)guanine (N7-HEG) with excellent sensitivity and specificity. [4,5,6,8-(13)C(4)]-N7-HEG was synthesized, characterized, and quantitated using HPLC/electrospray ionization mass spectrometry (HPLC/ESI-MS) so it could serve as an internal standard. After being converted to its corresponding xanthine and derivatized with pentafluorobenzyl (PFB) bromide twice, the PFB derivative of N7-HEG was characterized using GC/EC/NCI-HRMS carried out at full scan mode. The most abundant fragment was at m/z 555, with a molecular formula of C(21)H(9)N(4)O(3)F(10), resulting from the loss of one PFB group. By monitoring m/z 555.0515 (analyte) and m/z 559.0649 (internal standard), this assay demonstrated a linear relationship over a range of 1 fmol to 1 pmol of N7-HEG versus 20 fmol of [(13)C(4)]-N7-HEG on column. The limit of detection (LOD) for the complete assay was 600 amol (S/N = 5) injected on column. The variation of this assay was within 15% from 1 to 20 fmol of N7-HEG versus 2 fmol of [(13)C(4)]-N7-HEG with four replications for each calibration standard. Two hundred to three hundred micrograms of spleen DNA of control rats and mice and 100 microg of spleen DNA of rats and mice exposed to 3000 ppm ethylene for 6 h/day for 5 days were analyzed using GC/EC/NCI-HRMS. The amounts of N7-HEG varied from 0.2 to 0.3 pmol/micromol of guanine in tissues of control rats. Ethylene-exposed animals had 5-15-fold higher N7-HEG levels than controls. This assay was able to quantitate N7-HEG in 25-30 microg of DNA from human lymphocytes with excellent specificity. This was due in part to human tissues having 10-15-fold higher amounts of endogenous N7-HEG than rodents. These results show that this GC/EC/NCI-HRMS method is highly sensitive and specific and can be used in biological monitoring and molecular dosimetry and molecular epidemiology studies.

Dexon and nylon-sutured wound reaction in conjunctival flap after trabeculectomy combined with or without topical application of mitomycin-C.

In this study, rabbits were used to evaluate the sutured wound reaction with Dexon or nylon in the conjunctival flap 1, 4, 7, 14 and 28 days after trabeculectomy surgery with or without the use of mitomycin-C. Four major treated groups were used to compare their wound healing reaction; group 1--nylon-suture and non-mitomycin treatment; group 2--nylon-suture and mitomycin treatment; group 3--Dexon-suture and non-mitomycin treatment; group 4--Dexon-suture and mitomycin treatment. One day after surgery, the number of polymorphs was the greatest most in the nylon-sutured and non-mitomycin treated tissues (86 +/- 2). Four days after surgery, the number of polymorphs was the greatest most in Dexon-sutured and non-mitomycin treated tissues (109 +/- 87). The number of fibroblasts was the greatest most in nylon-sutured and non-mitomycin treated tissues (111 +/- 23). Seven days after surgery, the number of polymorphs was the greatest most in Dexon-sutured and mitomycin treated tissues (32 +/- 12). The number of fibroblasts was the greatest most in nylon-sutured and non-mitomycin treated tissues (126 +/- 15). Fourteen days after surgery, the number of fibroblasts was the greatest most in Dexon-sutured and non-mitomycin tissues (43 +/- 10). The number of goblet cells was the greatest most in nylon-sutured and non-mitomycin treated tissues (4 +/- 2). Twenty-eight days after surgery, the number of fibroblasts was the greatest most in Dexon-sutured and mitomycin treated tissues (40 +/- 15). The number of goblet cells was the greatest most in nylon-sutured and non-mitomycin treated tissues (4 +/- 2). Our conclusions are as follows: 1). The concentration of mitomycin in conjunctival wound edge should be maintained at as low a level as possible because the mitomycin will delay the wound healing process; 2). Nylon material is better than Dexon for conjunctival wound suture because nylon could induce a great quantity of fibroblasts before Dexon did.

Calcium-induced changes on crystallins in organ-cultured porcine lens.

In this study, intact porcine lenses were cultured in vitro for 7 days supplemented with commercial balanced salt solution (BSS) which is usually used as an irrigation solution during intraocular surgery, and the lenses were maintained under various culture conditions, e.g. temperature and CO2 concentration. The intact porcine lenses after 7 days culture were analyzed with optical density scanner, gel permeation chromatography on TSK HM-55 column and SDS-PAGE (polyacrylamide gel electrophoresis). It was found that lenses exhibited the least opacity when lenses were cultured with Ca(+2)-free BSS buffer, CO2-free incubator and maintained at a temperature of 25 degrees C. After the lenses were cultured with Ca(+2)-free BSS or BSS medium, the composition of crystallins in lenses was separated with TSK HM-55 column. It was indicated that the percentage of high molecular weight (HMW) protein and (alpha-crystallin increased, and gamma-crystallin decreased in lenses incubated with BSS medium compared with lenses incubated with Ca(+2)-free BSS medium. Following an increase in the concentration of calcium in the medium from 4.3 mM, 20 mM, 50 mM, 100 mM to 200 mM, the opacity of the lens was measured with a densitometer. The changed percentage of various crystallins was similar to lenses with BSS media that increased in HMW protein and alpha-crystallin, decreasing in gamma-crystallin. In the case of lens protein pattern, the crystallin washed from TSK HM-55 gel was separated with SDS-PAGE (polyacrylamide gel electrophoresis). It was indicated that some of proteins disappeared when lenses were incubated with various concentrations of calcium. The vanished pH proteins were 20.5 kDa at 50 mM calcium, 20.5 kDa and 21 kDa at 100 mM, 20.5 kDa, 21 kDa, 22 kDa and 23 kDa at 200 mM which were compared with the protein bands in the presence of 20 mM calcium in BSS medium. This study indicates that the commercial balanced salt solution (BSS) which is usually used as an irrigating solution during intraocular operations may increase the risk for lens opacity because of the calcium contained in the solution.