Characterization of the intestinal transport mechanism of polystyrene microplastics (MPs) and the potential inhibitory effect of green tea extracts on MPs intestinal absorption

The aims of the current study included characterizing the intestinal transport mechanism of polystyrene microplastics (MPs) with different charges and sizes in the intestinal epithelial cell model and determining the inhibitory effect of green tea extracts (GTEs) on the intestinal absorption of MPs in Caco-2 cells. The smaller sizes, which included diameters of 0.2 μm, of amine-modified MPs compared to either larger size (1 μm diameter, or carboxylate-MPs (0.2 and 1 μm diameter) significantly lowered the cell viability of caco-2 cells that were measured by MTT assay (p < 0.05). The transported amount (particles/mL of the cell media) of amine-modified MPs by the Caco-2 cell, was not dependent according to the concentrations, energy, or temperature, but it was higher than the carboxylate-modified MPs. The co-treatment of GTEs with the amine-modified MPs inhibited Caco-2 cell cytotoxicity as well as reduced the production of intracellular reactive oxygen species (ROS) in HepG2 generated by the exposure of amine-modified MPs. The GTEs co-treatment also increased trans-epithelial electrical resistances (TEER) and reduced the transportation of Lucifer Yellow via the Caco-2 monolayer compared to only the amine-modified MPs exposure. The GTEs treatment led to a decrease in the number of amine-modified MPs transported to the basal side of the Caco-2 monolayer. The results from our study suggest that the consumption of GTEs could enhance the intestinal barrier function by recovering intestinal epithelial cell damage induced by MPs, which resulted in a decrease of the intestinal absorption of MPs.

Effects of military life on changes in body mass index of enlisted men: a cross-sectional study

Background

Obesity is a serious health problem with an incidence that is increasing rapidly. Enlisted men are a distinctive group characterised by 24-hour community-living and are likely to experience changes in body weight as a result of regular diet and exercise during enlistment.

Methods

This study reviewed data from the Second Military Health Survey. Changes in body mass index (BMI) before and during military service were analysed using paired t-test. We calculated OR and 95% CI for factors affecting weight improvement during military service through logistic regression.

Results

The mean BMI in the underweight group increased by 5.87 kg/m² during service, while that in the normal weight group increased by 1.18 kg/m². In contrast, the mean BMI in the overweight group decreased by 5.47 kg/m² during service. The OR for an improved BMI in the subjective good health group compared with the subjective poor health group was statistically significant (OR=1.71, 95% CI 1.02 to 2.87). The OR for an improved BMI was significantly higher in the group with three or more times per week of strength training than in the group with one to two times per week of strength training, and was higher among the marines compared with the Army soldiers (OR=1.48, 95% CI 1.03 to 2.12 and OR=2.15, 95% CI 1.07 to 4.32, respectively).

Conclusions

Strength training showed a statistically significant increase in BMI during military service. Furthermore, the BMI of men who were underweight before their service increased, while it decreased among those who were overweight.

Asymptomatic Cerebral Vasoconstriction after Carotid Artery Stenting

BACKGROUND AND PURPOSE

Carotid artery stent placement is widely performed for treatment of carotid stenosis. The purpose of this study is to present our observations on cerebral vasoconstriction in ipsilateral anterior circulation during immediate poststenting angiography in patients with near-total occlusion of the proximal ICA.

MATERIALS AND METHODS

We retrospectively reviewed patient data from December 2008 to December 2018. There were 28 patients with carotid near-total occlusion. Two neuroradiologists reviewed the final cerebral angiographic finding of carotid artery stent placement to evaluate the presence of vasoconstriction or vasodilation.

RESULTS

A total of 28 patients with near-total occlusion (mean ± standard deviation age, 69.0 ± 6.5 years; 92.9% male) were analyzed. Ten patients showed vasoconstriction in the treated territory, and 18 patients did not show vasoconstriction after carotid artery stenting. There were no statistically significant differences in comorbidity, frequency of symptomatic lesions, antiplatelet medication, mean procedure time, and initial NIHSS and baseline modified Rankin scale scores between the 2 groups. However, vasoconstriction is more likely to happen in patients with isolated territory from the contralateral anterior and posterior circulation (66.7% in the isolated territory group and 12.5% in the not-isolated territory group; P < .05). No headache or neurologic deficit was noted in all 10 patients with cerebral vasoconstriction.

CONCLUSIONS

Cerebral vasoconstriction may occur after carotid artery stenting more frequently than expected. It occurs more frequently in patients with near-total occlusion and with isolation of the cerebral circulation. A large-scale study is necessary to assess the clinical implications of cerebral vasoconstriction after carotid artery stenting.

336 QUANTITATIVE ANALYSIS OF TETRACYCLINE-INDUCIBLE EXPRESSION OF THE GREEN FLUORESCENT PROTEIN GENE IN TRANSGENIC CHICKENS

The use of transgenic farm animals as bioreactors to address the growing demand for biopharmaceuticals, both in terms of increased quantity and greater number, represents a key development in the advancement of medical science. However, the potential for detrimental side effects as a result of uncontrolled constitutive expression of foreign genes in transgenic animals is a well-recognised limitation of such systems. Previously, using a tetracycline-inducible expression system, we demonstrated the induction of expression of a transgene encoding green fluorescent protein (GFP) in transgenic chickens by feeding with doxycycline, a tetracycline derivative; expression of GFP reverted to pre-induction levels when the inducer was removed from the diet (Kwon et al. 2011 Biochem. Biophys. Res. Commun. 410, 890–894). As a proof of principle study, however, quantitative assessment of expression was not possible, as only 1 G0 and 1 G1 transgenic chicken was obtained. In the current study, with 7 G2 transgenic chickens obtained from 1 G1 hen, we confirmed stable genomic integration of a single copy number of the transgene by Southern blot analysis. As we have observed in G1 transgenic chicken previously, all of the G2 transgenic chickens emitted a green fluorescence upon doxycycline feeding (50 mg kg–1 of formula feed). Fluorescence became detectable 4 days after starting doxycycline feeding, and maximum GFP expression was detected after 2 weeks. Removal of doxycycline from the diet after 14 days of induction feeding resulted in the return of external fluorescence to pre-induction levels after 39 days. Quantitative analysis of gene induction was done using protein and mRNA extracted from primary cultured cells derived from 6-day transgenic chicken embryos. The eggs were obtained by mating a nontransgenic wild-type hen with 1 of G2 transgenic roosters. Protein levels of GFP were analysed by immunoblot and quantified using a densitometer. In the absence of doxycycline, the amount of GFP per 1 µg of total protein was 0.2 ng. However, when the cells were treated with doxycycline for 6 days, the amount of GFP increased to 3.1 ng per 1 µg of total protein, which was 16-fold higher than that of the cells pre-treated with doxycycline. Switching to doxycycline-free medium after doxycycline induction resulted in significant abrogation of GFP expression in 6 days; the amount of GFP reduced from 3.1 to 0.5 ng, a 6.2-fold reduction. Transcription of the GFP gene was also assessed by Northern blot. The amount of GFP mRNA measured by band density increased as much as 20-fold (3.9/0.2) with 6 days of doxycycline induction and declined to 1/8 (3.9/0.5) when doxycycline was removed from the cell culture media for 6 days. The use of an inducible expression system that can be regulated by dietary supplementation could help mitigate the physiological disruption that can occur in transgenic animals as a result of uncontrolled constitutive expression of a transgene.

CYP2C19 haplotypes in Koreans as a marker of enzyme activity evaluated with omeprazole

BACKGROUND AND OBJECTIVE

CYP2C19 is clinically important in Korea because of the relatively high incidence of poor metabolizers in the population. To fully understand the genetic mechanism of the CYP2C19 defect in poor metabolizers, all variants need to be studied simultaneously. The aim of this study was to investigate the usefulness of CYP2C19 haplotypes as a marker of CYP2C19 enzyme activity in Koreans.

METHODS

We analysed the single nucleotide polymorphisms and haplotypes of the CYP2C19 gene in 150 healthy Koreans and found three major (frequency > 0.1) haplotypes (H1, H2 and H3). One oral dose of 40 mg omeprazole (Losec) was administered to 30 subjects grouped as H1/H1, H2/H2, H1/H2, H1/H3 and H2/H3. The pharmacokinetics of omeprazole and its metabolites, 5-hydroxyomeprazole and omeprazole sulphone, in those groups was analysed.

RESULTS AND DISCUSSION

The area under the plasma concentration-time curve (AUC(0-->infinity)) and elimination half-life (T(1/2)) of omeprazole were significantly greater in the H2/H2 and H2/H3 groups than in the H1/H1 group (P < 0.05), whereas the metabolic ratios of omeprazole to 5-hydroxyomeprazole were also markedly higher.

CONCLUSION

Although a specific SNP of CYP2C19 may be predictive of enzyme activity, haplotyping is more reliable for identifying poor metabolizers in populations with variant alleles other than CYP2C19*2 and *3 alleles.

Clinical outcome of sequential chemotherapy in metastatic and/or recurrent gastric cancer

e15521

Background: Little is known about data on subsequent chemotherapy (CTx) following 1st-line CTx in stage IV gastric cancer. The purpose of this study was to analyze the natural history of stage IV gastric cancer with sequential CTx Methods: A total of 532 patients (pts) with unresectable gastric adenocarcinoma were studied. They were managed with a strategy of maximal administration of CTx only if pts’ general conditions were allowed. Response evaluation was performed by RECIST every 2 cycles. Response of unmeasurable lesions was dichotomized only into stable disease or progressive disease. Results: When pts were divided into CTx group (460 of 532, 87%) and best supportive care group (BSC; 72 of 532, 13%) resulting from poor performance/pt's refusal/comorbidity (31/23/18), the former had younger age (p = 0.046), better performance (p < 0.001), and less advanced metastatic sites (p = 0.001) than the latter. Median overall survivals from diagnosis of unresectable cancer were 12.0/13.3/2.5 months for overall/CTx/BSC, respectively. 87%/47%/23% of the whole pts received 1st/2nd/3rd-line CTx, respectively. Median number of regimens delivered was 2. Maximally 5th-line CTx was given to 15 pts (3%). Response and disease control rates were 21.7%/12.5%/11.8% and 79.4%/56.3%/49.4% for 1st/2nd/3rd lines, respectively. Median progression-free and overall survivals from CTx were 5.5/3.4/2.5 months and 12.1/7.9/5.5 months for 1st/2nd/3rd lines, respectively. The most common cause of discontinuation of CTx was disease progression (68%/74%/70%) followed by pt's refusal (22%/13%/12%) for 1st/2nd/3rd lines, respectively. Prognosticators were performance status, histology, metastatic site, and CTx before 1st or 2nd line. Conclusions: When pts with unresectable gastric cancer were managed with a strategy of maximal administration of CTx, a considerable number of pts could receive 2nd or 3rd line CTx, showing modest activity. Performance status and metastatic site were consistent prognosticators even if lines changed. Our data on the natural history of stage IV gastric cancer with sequential CTx may suggest that clinical trials can be performed in a 2nd or 3rd line setting as well.

No significant financial relationships to disclose.

Comparison of long-term outcome between doublet versus triplet neoadjuvant chemotherapy in nonmetastatic osteosarcoma of extremity

10542

Background: Multimodal approach had improved outcomes of non-metastatic osteosarcoma. This study was to compare outcomes between doublet (AP; doxorubicin and cisplatin) and triplet (IAP; AP and ifosfamide) neoadjuvant chemotherapy for non-meteastatic osteosarcoma of extremity in a single institute. Methods: A total of 124 osteosarcoma patients were enrolled. In AP group, doublet regimen was given to 77 patients from 1991 to 1999, who received intra-arterial cisplatin(120mg/m2) at day 1 and intravenous doxorubicin (25mg/m2) for 3 days. In IAP group, triplet regimen was given to 49 patients from 2000 to 2007, who received ifosfamide additionally at a dose of 2.5g/m2/day for 3 days. After completion of 3 cycles of chemotherapy, patients underwent limb-salvage surgery. We assessed tumor response according to pathologic tumor necrosis, and treated further adjuvant chemotherapy. In AP group, responder received 3 more cycles of AP, while non-responders received 6 cycles of ifosfamide-contaning regimens. In IAP group, all patients had 3 more cycles of IAP chemotherapy. Results: The median follow-up duration was 5.2 years (0.4–16.7). The most frequent site and histology were distal femur and osteoblastic type. Overall pathologic response was more than 90% tumor necrosis in 74.8% of patients. Total necrosis of tumor was also found in 46 patients (37.4%). There was no difference between two groups in pathologic response (76.3% vs. 72.3%; p=0.62) or other clinico-pathologic parameters. Tumor recurrence was occurred in 31.5% of patients with the most common site of lung (84.6%). There was no difference between two groups in recurrence (p=0.17) or lung metastasis (p=0.53). There were no statistical differences in disease free survival (p=0.75) and overall survival (p=0.07) between two groups. In toxicity profiles, there were more hematologic toxicity in IAP group (febrile neutropenia,p<0.001; thrombocytopenia,p<0.05), while there were no statistical differences in treatment related death. Conclusions: The addition of ifosfamide to doxorubicin and cisplatin in neoadjuvant chemotherapy did not show improved outcomes in this study. Further trials are required to elucidate optimal neoadjuvant chemotherapy and effective salvage regimens.

No significant financial relationships to disclose.

Predictive factors associated with clinical outcome and safety in Korean patients with metastatic renal cell carcinoma treated with sunitinib

e16111

Background: Sunitinib has become a standard treatment for metastatic renal cell carcinoma (RCC). The research for identifying patients who are more likely to benefit from this agent is quite limited, especially in Asian patients. Methods: In total, 81 histologically proven metastatic RCC patients who were treated with sunitinib were reviewed between Jan 2006 and Dec 2008. Tumor response was evaluated according to the RECIST criteria, and safety was assessed by NCI-CTC (version 3.0). Primary endpoint was progression-free survival (PFS) and secondary endpoints included overall survival (OS), overall response rate (ORR), disease control rate (DCR), and toxicities. Clinical features associated with clinical outcome were identified by univariate analysis; then, a stepwise modeling approach based on Cox's proportional hazards regression was used to identify independent prognostic factors to these endpoints. Results: Median age was 58 years (range, 29 to 73), and 33 patients received sunitinib as first-line systemic treatment. Clear cell type was predominant (85%). Patient distribution was 12% for favorable, 78% for intermediate, and 10% for poor group according to the MSKCC risk group. With the median follow-up of 26 months, median PFS was 16 months (95% CI, 8 –24) and median OS was 24 months (95% CI, 18 –30). ORR was 30% (95% CI, 19–40%) and DCR was 80% (95% CI, 70–89%). The most common grade 3/4 adverse events of sunitinib was thrombocytopenia (32%). Other severe toxicity included neutropenia (21%), anemia (19%), leucopenia (14%), fatigue (10%), stomatitis (10%). In multivariate analysis, the previous exposure to immunotherapy was related to longer PFS (P<.012). Performance status (ECOG 0–1) and corrected Ca level (8.5∼10.5 mg/dl) were associated with favorable ORR (P=.038) and DCR (p=0.008), respectively. Predictive factors for grade 3/4 thrombocytopenia were corrected Ca level (P=.018), poor MSKCC risk group (P=.025), and low WBC count (<4500/ul, P=.041). Conclusions: Compared to western reports, our data demonstrated comparable clinical efficacy in Asian patients, but different safety profile, especially in hematologic toxicities. This approach provides a tailored approach to predictive factors for targeted agents.

No significant financial relationships to disclose.

304 PRODUCTION OF TRANSGENIC CHICKENS EXPRESSING HUMAN ERYTHROPOIETIN IN A TETRACYCLINE-INDUCIBLE MANNER

The use of livestock animals as bioreactors to address the growing demand for large quantities and increasing numbers of biopharmaceuticals is of prime strategic relevance to agricultural improvement and medical advancement. We report here the production of transgenic chickens that produce human erythropoietin (hEPO) using replication-defective Moloney murine leukemia virus-based vectors. Because it is well known that constitutive overexpression of some cytokine genes in the transgenic animals may cause serious physiological disturbances, the vectors were designed to express in the presence of tetracycline. In addition, we introduced woodchuck hepatitis virus posttranscriptional regulatory element sequence at 3′ end of hEPO gene to boost the gene expression under the inducible condition. Approximately 5 μL of vector virus solution concentrated as much as 109 cfu mL–1 was injected beneath the blastoderm of non-incubated chicken embryo (stage X). Out of 596 injected eggs, 36 chicks hatched after 21 days of incubation and 23 hatched chicks were found to express vector-encoded hG-GSF gene when fed with doxycycline. Quantitative analysis of the blood samples taken from some Go transgenic chickens resulted in more than 300 IU mL–1 of hEPO in the blood. These transgenic chickens have not exhibited any physiological abnormalities; therefore, it is possible that this controllable gene expression system may be useful in minimizing detrimental side effects when used to produce other transgenic animals. The biological activity of the recombinant hEPO was comparable to its commercially derived Escherichia coli counterpart. The significance of this work stems from the fact that it is the first successful report on the production of transgenic chickens expressing the hEPO gene. This approach can be employed to create a useful transgenic model system for further studies on the chicken embryo development and the efficient production of transgenic chickens as bioreactors. This work was supported by: The BioGreen 21 Program of the Rural Development Administration, Republic of Korea; The SRC/ERC program of MOST/KOSEF (grant no. R11-2002-100-04005-0); The 2006–2011 Technology Development Program for Agriculture and Forestry (TDPAF), Ministry of Agriculture and Forestry, Republic of Korea.

Phase I trial of neoadjuvant concurrent chemoradiotherapy with S-1 and weekly irinotecan in locally advanced rectal cancer

14543

Background: S-1 is a novel, orally administered 5-FU analogue and is known of radiosensitizer. The aim of this study was to establish the feasibility and efficacy of S-1 in combination with weekly irionotecan with concurrent pelvic radiotherapy (RT) in patients with locally advanced rectal cancer. Methods: Clinical stage T3–4 or N+(on MRI) rectal adenocarcinoma patients received weekly irinotecan 40mg/m2(day1,8,15,22,29) and S-1 at dose levels of 40, 50, 60 and 70mg/m2 (5days a week from day 1 to 38) according to phase I methodology. Concurrently conventional RT was given at daily fractions of 1.8 Gy on 5 days a week for a total dose of 50.4 (45 + 5.4)Gy. Surgery was performed 4–8 weeks following completion of chemoradiation. Results: A total 16 patients (10M/7F, median age 46 years, ECOG PS0–1) were enrolled between August 2005 and July 2006. One pt withdrew the consent during CCRT. Dose-limiting toxicity (DLT) occurred at 50mg/m2 of S-1 in one of six pts (G4 cerebral infarction). At dose of 60, 70mg/m2 of S-1, no DLT occurred. G3/4 toxicties were rare. Fifthteen pts underwent surgery and R0 resection was achieved in 13 pts. Four pts (25.0%) had a pathological complete response. Conclusions: The recommended dose (RD) for further study is S-1 70mg/m2 with irinotecan and radiotherapy. Neoadjuvant S-1/irinotecan/RT is feasible and well tolerated. Phase II trial is being conducted.

No significant financial relationships to disclose.

Mobilized circulating endothelial progenitor cells after the first cycle of chemotherapy with prophylactic G-CSF can be used as a predictive biomarker and patient selection marker for anti-angiogenesis combination treatment

4638

Background: We investigated whether the level of circulating endothelial progenitor cells (CEPs) and endothelial cells (CECs) could be used as surrogate predictors of clinical outcome in patients receiving taxotere-based chemotherapy for advanced gastric cancer. Methods: Peripheral blood mononuclear cells were obtained in 49 gastric cancer patients who received taxotere combined with 5-FU and leucovorine (FLT regimen) after chemotherapy and prophylactic G-CSF treatment. To categorize the endothelial cells, immunofluorescent staining for specific endothelial cell markers (CD34, vWF, P1H12, CD31) was used. The changes of CEPs and CECs and their clinical significance on the response prediction and prognosis were analyzed. Results: After the first cycle of chemotherapy, the numbers of CD34+/vWF+, CD34+, vWF+, P1H12+ and CD31+ cells of 49 patients were 19.5 (2.7% of PBMCs), 20.1 (2.7%), 30.0 (4.8%), 12.9 (2.7%) and 214.3 (26.5%) cells/ml, respectively. The number of CD34+/vWF+ and CD34+ cells after the first and second cycle of chemotherapy were found to be higher in non-responders than responders (the first cycle: P=.012 and P=.008, the second cycle: P=.027 and P=.013, respectively). Moreover, the level of CD31+ cells after the second cycle of chemotherapy were significantly decreased compared with the first cycle in the patients who showed response (P=.026). In non-responders, however, the level of CD34+ cells was significantly increased after the second cycle of chemotherapy (P=.034). The level of CD34+ cells significantly related to the median time to progression (TTP) (6.1 and 4.0 months in CD34low and CD34high, respectively, cutoff level: 5.8, P=.046). Conclusion: CD34+/vWF+ and CD34+ cells can be used as a biomarker for prediction and prognosis in taxotere-based chemotherapy. CEP after the first cycle of chemotherapy can be a selection marker for addition of anti-angiogenic treatment after chemotherapy.

No significant financial relationships to disclose.

Rehabilitative orthotics evaluation in children with diplegic cerebral palsy: kinematics and kinetics

Ankle foot orthoses (AFOs) are prescribed for ambulatory children with spastic diplegia to improve biomechanical alignment and functional capability. The purpose of this study was to employ quantitative motion analysis of the lower extremity to investigate two rehabilitative orthotics. The effects of hinged ankle foot orthoses (HAFO) and dynamic ankle foot orthoses (DAFO) for joint ankle management in children with cerebral palsy were compared. Sixteen (16) independently ambulatory children with a diagnosis of spastic diplegic cerebral palsy (7.5 +/- 2.9 yrs.) were included in the study. The biomechanical effects of two AFO designs were compared to barefoot using a 3-D motion analysis system. Significant differences between braced and unbraced conditions were found in peak ankle dorsiflexion, and peak ankle plantarflexion, knee stance peak flexion, knee swing peak flexion, hip stance peak flexion, and peak ankle plantarflexion moment (p < 0.01). Differences between the HAFO and DAFO were not seen in the kinematic and kinetic metrics. Further development of dynamic testing is suggested in order to advance our understanding of orthotic intervention. The value of quantitative description of gait dynamics is clearly indicated for rehabilitative application.

Chemoradiation and maintenance chemotherapy with cisplatin and 5-fluorouracil in anal squamous cell carcinoma

14057

Background: Chemoradiation is the standard treatment for anal carcinoma. Mitomycin-C (MMC) with 5-fluorouracil (5-FU) is the widely used regimen, but MMC is not a radiation sensitizer and has significant toxicities. This study was conducted to update our experience in treating anal carcinomas with an external beam radiation and continuous infusion of 5-FU with cisplatin. Methods: Twenty-eight patients with locally advanced squamous cell carcinoma of the anus were treated between 1995 and 2005. The primary tumor and involved lymph nodes received a total of 41.4–64.8 Gy and 39.6–60.4 Gy, respectively. Chemotherapy consisted of 5-FU (1,000 mg/m2 CI, D1–5 and D36–40) and cisplatin (80 mg/m2 IVF, D2 and D37) q 4weeks for 4 courses. Results: One patients had T1 lesions, 15 had T2, 7 had T3, and 5 patients had T4 disease. Seventeen patients presented with clinically detectable lymphadenopathy. Eight patients failed to start maintenance chemotherapy due to events during chemoradiation. Of the 19 patients who started maintenance chemotherapy, 3 failed to complete all four courses due to intolerance to chemotherapy. With a median follow-up duration of 68.5 months, the actuarial 5-year OS rate was 83.2 %, the DFS rate 80.7%, and the colostomy-free survival was 91.7%. Patterns of recurrence were local relapses in 3 patients, distant metastases in 2, and both in 1, respectively. Seventeen patients (60.7%) developed moist skin reaction, which frequently caused the interruption of radiotherapy. Principal grade 3/4 hematologic toxicities were neutropenia in 10 patients (35.8%) and thrombocytopenia in 4 (14.2%). The most common late complications were lymphedema (14.3%). Conclusions: Our results demonstrate that combined modality therapy with external beam radiation, cisplatin and 5-FU yields an excellent outcome in terms of survival and sphincter preservation which is comparable to the results of MMC regimens.

No significant financial relationships to disclose.

Phase II study of oral S-1 monotherapy in metastatic colorectal cancer after failure of both irinotecan and oxaliplatin-containing regimen

3597

Background: There has been a considerable increase in the number of patients (pts) with mCRC pretreated with both irinotecan and oxaliplatin. Little is known about third-line therapy in this group of pts. We conducted a phase II trial of oral S-1 in pts with advanced colorectal cancer who failed on both irinotecan and oxaliplatin. Methods: This phase II study was designed to evaluate the activity and toxicity of S-1 monotherapy in 31 advanced colorectal cancer pts (P0 = 3%, P1 = 15%; α = 0.05, power = 80%, drop-out rate 10 %). S-1 was administered orally twice daily, 70 mg/m2/day for 14 days followed by 1-week rest. Eligibility criteria included ECOG 0–2; measurable lesion; adequate organ functions; signed informed consent. Results: As of 1st September 2005, 21 pts were enrolled. Median age of all pts 55 years. There were 10 male and 11 females. Thirteen of 21 patients were treated with oxaliplatin-containing regimens as a first-line therapy for metastatic diseases. The median number of treatments was 3 courses (range, 1–10). The relative dose intensity was 1.0 (0.83 - 1.0) with a median dose of120 mg (100 -140 mg). Nineteen out of 21 patients were evaluable. The confirmed response rate was 21.1% (4/19, 1 CR, 3 PR). The median PFS was 11 weeks, and median OS was not reached. The most frequent adverse reaction was skin pigmentation (47.6%). Grade 3 toxicities was skin pigmentation in 1 patients (4.8%), neutropenia in 1 (4.8%), and anemia in 1 (4.8%), respectively. Conclusion: This results shows that S-1 produces a promising response rate with an acceptable safety profile in refractory, mCRC. S-1 has the potential to become a valuable option as a third-line salvage regimen in irinotecan and oxaliplatin pretreated mCRC pts. Clinical trial of combination therapy with S-1 will be warranted.

No significant financial relationships to disclose.

Overall view of occupational health services in Korea

Occupational health services in Korea can be largely divided into periodic health examination for workers, group health care system for workers in small and medium size industries, and workplace environment measurement. Periodic health examination is composed of general and special health examination. General health examination is performed once every two years for office workers and once every year for production workers. The expenses of medical examination are covered by public medical insurance program. Special health examination is performed on workers who dealt with hazardous agents with variable durations. The employer pays the expense of special health examination. Group health care system has been established for small and medium sized industries exempt for assignment of full-time health managers (physician, nurse, hygienist). It entrusts the role of health managers to occupational health organization or clinic. Especially, entrust fee of small sized industries are paid by government. The levels of hazardous agents are measured in all workplace environment. If the measured level exceeds the permissible exposure level, the employer is enforced to improve the workplace environment with their own expense. In 1997, 684,000 workers received periodic health examination and 2,400 workers were found with occupational diseases.

Polymorphisms in codon 31 of p21 and cervical cancer susceptibility in Korean women

The aim of this study was to determine whether the codon 31 genotype of p21 might be associated with an increased risk of cervical cancer development in Korean women. We used tissue derived from patients with invasive cervical cancer (ICC) (n=111, composed of two histologic groups: squamous cell carcinoma (n=67) and adenocarcinoma (n=44)), cervical intraepithelial neoplasia (CIN) III (n=101), and non-cancer controls (NCC, n=98). For the determination of p21 polymorphism, genomic DNA was examined by polymerase chain reaction-restriction fragment length polymorphism assay using BsmAI. We compared the distribution of the p21 genotype in ICC, CIN III, and control and also analyzed the association of this polymorphism with the risk of development of cervical cancer, especially in patients with high-risk human papillomavirus (HPV) (16 or 18)-positive cervical cancer. A significant increase of Ser/Ser genotype frequency was found in adenocarcinoma patients with high-risk HPV (16 or 18) compared with the NCC group (P=0.009). The odds ratio was 3.59 (95% CI 1.55-8.31) when comparing adenocarcinoma patients associated with high-risk HPV with NCC. We found that the codon 31 Ser/Ser homozygote of the p21 gene could be a risk factor for the development of cervical adenocarcinoma associated with high-risk HPV.

Effect of temperature on the breakthrough of a charcoal tube during vinyl chloride monomer sampling

This study evaluated the effects of temperature on breakthrough of two standard collection media at various concentrations during vinyl chloride monomer (VCM) sampling. The National Institute for Occupational Safety and Health (NIOSH) and Occupational Safety and Health Administration (OSHA) methods were evaluated. To determine whether breakthrough of VCM would occur at the extremes of exposure and temperature that might be encountered in some workplaces, air samples containing 4 ppm (10.24 mg/m3), 8 ppm (20.45 mg/m3), 16 ppm (40.98 mg/m3), and 32 ppm (81.80 mg/m3) of VCM were collected at temperatures of 4, 22, and 40 degrees C. Five liters of air was sampled at the rate of 0.05 L/min for 100 min using the activated charcoal tube recommended by NIOSH. A second tube was added to the sampling train to collect any VCM that might not have been absorbed in the first tube. To collect VCM air samples by the OSHA method, two carbon molecular sieve tubes were connected serially and 3 L of air was sampled at the rate of 0.05 L/min for 60 min. A gas chromatograph with a flame ionization detector and ultra 2 capillary column was used to analyze VCM. Significant breakthrough was found when sampling at higher temperatures with the NIOSH method. No breakthrough was found when samples were collected using the OSHA media at different temperatures and concentrations. Therefore, under hot ambient conditions (>22 degrees C), the possibility of breakthrough should be considered when sampling VCM by the NIOSH method.

Protective effects of garlic juice against embryotoxicity of methylmercuric chloride administered to pregnant Fischer 344 rats

In order to investigate the beneficial effects of 0.5 or 1.0 g/kg Korean garlic juice against the embryotoxicity of 20 mg/kg methylmercury chloride (MMC, CH3HgCl), pregnant Fisher 344 rats were simultaneously orally administered on day 7 of gestation. On day 20 of gestation the dams were laparotomized under ether anesthesia, and the fetuses were removed and examined for toxicity of methylmercury. Garlic juice depressed the toxicity in terms of some parameters. In the case of simultaneous treatment with 0.1 g/kg garlic juice and MMC, rates of increase were 17.5% in maternal body weight, 13.2% and 41.9% in fetal and litters' weight respectively, and 37.0% in fetal survival rate. Decreasing rates were 10.0% in maternal death rate, and 6.9% and 31.3% in pre- and post-implantation loss respectively. Decreasing rates of mercury levels in dams were 67.2% in liver, 57.6% in brain, 47.2% in kidney, 42.1% in spleen and 40.9% in blood. As well, decreasing rates of mercury level in fetuses were 54.9% in all body burden, 55.9% in liver, 46.7% in kidney and 37% in brain, respectively. The number of fetal ossification centers were reduced by 23.8% to 58.0% following simultaneous treatment with 1.0 g/kg garlic juice. These findings indicated that garlic juice effectively inhibited the embryotoxicity of methylmercury in pregnant Fischer 344 rats.

Simultaneous analysis of urinary 2-thiothiazolidine-4-carboxylic acid and thiocarbamide as a biological exposure index for carbon disulfide exposure

The objectives of this study were to develop optimal analytic methods for detecting urinary 2-thiothiazolidine-4-carboxylic acid (TTCA) and thiocarbamide simultaneously and to evaluate the usefulness of these metabolites to a biological exposure index (BEI) for carbon disulfide (CS2) exposure. For this experiment, synthesized TTCA and thiocarbamide were used. The synthesized TTCA was identified by infrared spectrophotometer, nuclear magnetic resonance spectrometer and thin layer chromatography. The recovery rates of both metabolites were calculated to find the optimum analytical method. The amounts of urinary TTCA and thiocarbamide were measured by using an ultraviolet detector connected to high performance liquid chromatography (HPLC) after the administration of CS2 (350, 700 mg/kg) into Sprague-Dawley rats intraperitoneally. The maximum absorbance wave lengths for TTCA and thiocarbamide were 272 and 236 nm, respectively. Ethyl acetate extraction with NaCl as a salting-out reagent was used as a simultaneous extraction method for these metabolites. HPLC conditions for these metabolites included using a NH2 column, 50 mM KH2PO4: acetonitrile (85:15) and pH 3. Excreted amounts of urinary TTCA and thiocarbamide were increased significantly following CS2 administration. TTCA, which was already adopted as a BEI for CS2 by the American Conference of Governmental Industrial Hygienists (ACGIH), seems to be a more useful BEI for CS2 exposure than thiocarbamide. However further studies are needed to increase analytical efficiency before thiocarbamide can be adopted as a BEI and to apply this analytic method for simultaneous analysis of these metabolites in workers exposed to CS2.

Molecular biomarkers of occupational lung cancer

Occupational exposures to certain metals, hydrocarbons and ionizing radiation are associated with increased lung cancer in workers; because these exposures continue, lung cancer remains an important problem in industrialized nations. The gravity of the lung cancer, specifically the low cure rate associated with the disease, has forced researchers to focus efforts at developing biological indicators (biomarkers) of carcinogen exposure and early, reversible effects. This review examines critically the development of these biomarkers for occupational and environmental exposures to polycyclic aromatic hydrocarbons (PAH), a ubiquitous class of lung carcinogens. Biomarkers of several different stages of the carcinogenic process have been proposed. Industrial hygiene and occupational health emphasize exposure and disease prevention. For this reason, biomarkers useful in industrial hygiene practice are those which measure events prior to the initiation phase of carcinogenesis; markers of later events which have a greater positive predictive value may measure irreversible effects and are more appropriate for disease screening and epidemiology. One of the strengths of biological monitoring is that exposures and effects can be measured regardless of route. Data indicates that the dermal route may be a significant pathway for delivery of PAH to the lung. This finding has important ramifications because as airborne exposure limits decrease the relative impact of dermal absorption is increased.

32P-postlabelling analysis of dibenz[a,j]acridine-DNA adducts in mice: identification of proximate metabolites

N-Heterocyclic polynuclear aromatics are widely-occurring environmental pollutants formed during the pyrolysis of nitrogen-containing organic chemicals. Dibenz[a,j]acridine (DBA), a member of this class, has been shown to be a skin carcinogen in mice. We undertook studies to determine the organ distribution of DBA-DNA adducts and to identify the DBA metabolites which lead to the formation of carcinogen-DNA adducts in vivo. DBA and its metabolites, trans-DBA-1,2-dihydrodiol (DBA-1,2-DHD) trans-DBA-3,4-dihydrodiol (DBA-3,4-DHD) and trans-DBA-5,6-dihydrodiol (DBA-5,6-DHD), were topically applied on mice. DNA was isolated using enzyme-solvent extraction methods, and analyzed for carcinogen-DNA adducts using 32P-postlabelling. In skin, DBA produced two distinct adducts (Adducts 1 and 2). The same two adducts were seen when DBA-3,4-DHD was applied. In addition, the total adduct level elicited by DBA-3,4-DHD was twice that of the parent compound. Two adducts (Adducts 3 and 4) were also seen in mouse skin when DBA-5,6-DHD was applied, but these differed chromatographically from adducts seen with DBA. However, when DBA-3,4-DHD was applied and analyzed using sensitive nuclease P1 32P-postlabelling, all four adducts could be detected. These results suggest that the major route of DBA activation to DNA-binding species in skin is through formation of DBA-3,4-DHD and subsequent metabolism of this compound to a bay-region diol-epoxide. However, we postulate that another activation pathway may proceed through a bis-dihydrodiol-epoxide.

32P-postlabeling analysis of dibenz[a,j]acridine DNA adducts in mice: preliminary determination of initial genotoxic metabolites and their effect on biomarker levels

N-Heterocyclic aromatics (NHA) are widely occurring environmental pollutants formed during the pyrolysis of nitrogen-containing organic chemicals. NHA are found in significant amounts in tobacco condensates, synthetic fuels, gasoline engine exhaust, and effluents from the heating of coal. Dibenz[a,j]acridine (DBA) is an example of NHA. The potency of many carcinogenic compounds is related, at least in part, to the efficiency of their biological activation. We undertook studies to determine which initial metabolites of DBA lead to the formation of high levels of carcinogen-DNA adducts in vivo. DBA and its metabolites, trans-DBA-1,2-dihydrodiol (DBA-1,2-DHD), trans-DBA-3,4-dihydrodiol (DBA-3,4-DHD), and trans-DBA-5,6-dihydrodiol (DBA-5,6-DHD), were applied to the skin of mice. DNA was isolated using enzyme-solvent extraction method. DNA was 32P-postlabeled under conditions of limiting [32P]ATP. In skin, DBA produced two distinct adducts. The same two adducts were seen when DBA-3,4-DHD was applied. In addition the total adduct level elicited by DBA-3,4-DHD was higher than that of parent compound. Two adducts were seen when DBA-5,6DHD was applied, but these were very different from adducts seen with DBA. These results suggested that activation of DBA to DNA-binding compounds in skin includes initial formation of DBA-3,4-DHD. The data support development of biomarkers for the exposure and effect of this compound, and also suggest that specific metabolic susceptibility markers might be able to predict populations at increased risk.