Acro-osteolysis in a Filipino male with Vinyl chloride exposure: A case report

@#Occupational acro-osteolysis pertains to bone resorption of the distal phalanges of the hands and feet among workers with vinyl chloride exposure. We report the case of a Filipino man with osteolysis of the distal phalanges of the hands initially considered to have systemic sclerosis. The patient had gradual shortening of the fingers, thickening of the skin over the extremities, and hypopigmented patches over a span of more than 20 years. His lower extremities presented with non-pitting edema, skin thickening, and neuropathy, without shortening of the digits. Difficulty of ambulation was apparent due to the development of feet inversion. Radiographic findings of the hands and feet included resorption of distal phalanges, erosive and sclerotic changes, and narrowed joint spaces. Other conditions considered were Hansen’s disease, skeletal tuberculosis, and diabetic neuropathic arthropathy, which were eventually ruled out. The final diagnosis was occupational acro-osteolysis secondary to vinyl chloride exposure. The patient underwent serial total contact casting of the bilateral lower extremities to relieve bipedal edema and to reposition the feet. This case emphasizes the significance of investigating a patient’s occupational history and highlights a rare sequela of exposure to a commonly used chemical agent in the manufacture of polyvinyl chloride products.

Research on the standard limits for vinyl chloride and trichloroethylene in the "Standards for Drinking Water Quality（GB5749-2022）" in China / 中华预防医学杂志

The usage of vinyl chloride and trichloroethylene in China has been increasing year by year, and they have been detected in both drinking water and environmental water, making them important environmental pollutants. Based on the latest research results on the health effects of vinyl chloride and trichloroethylene, the newly issued, "Standards for Drinking Water Quality (GB5749-2022)" in China has adjusted the standard limit of vinyl chloride from 0.005 mg/L to 0.001 mg/L and the standard limit of trichloroethylene from 0.07 mg/L to 0.02 mg/L. This article analyzed and discussed the relevant technical contents for determining the above standard limits, including the levels and exposure conditions of vinyl chloride and trichloroethylene in the water environment, health effects, derivation of safety reference values, and determination of hygiene standard limits. Suggestions were also made for the implementation of this standard.

Raynaud's phenomenon in the occupational context

SUMMARY OBJECTIVE To review articles that evaluated the prevalence of Raynaud's phenomenon of occupational origin. METHODS The search for articles was carried out in the Medline (via PubMed), Embase, Web of Science, Scientific Electronic Library Online (SciELO), and Latin America and Caribbean Health Sciences Literature (Lilacs) databases. RESULTS 64 articles were obtained from the electronic search; 18 articles met the eligibility criteria. All studies discussed the exposure to vibrations in the upper limbs. In 6 of them, the thermal issue was directly or indirectly addressed. No studies have addressed exposure to vinyl chloride. CONCLUSIO In general, a higher prevalence of Raynaud's phenomenon was found among vibratory tool operators compared to non-exposed workers, with an increase in the number of cases the higher the level of vibration and the time of exposure. Cold is a triggering and aggravating factor of the Raynaud phenomenon and seems to play an important role in the emergence of vascular manifestations of the hand-arm vibration syndrome.

RESUMO OBJETIVO Realizar um estudo de revisão dos artigos que avaliaram a prevalência do fenômeno de Raynaud de origem ocupacional. MÉTODOS A busca pelos artigos foi realizada nas bases de dados Medline (via PubMed), Embase, Web of Science, Scientific Eletronic Library Online (SciELO) e Literatura Latino-Americana e do Caribe em Ciências da Saúde (Lilacs). RESULTADOS Sessenta e quatro artigos foram obtidos a partir da busca eletrônica, dos quais 18 cumpriram os critérios de elegibilidade. Todos os estudos discutiram sobre a exposição a vibrações localizadas em membros superiores. Em seis deles, a questão térmica foi direta ou indiretamente abordada. Nenhum estudo abordou a exposição ao cloreto de vinila. CONCLUSÃO De maneira geral, constatou-se maior prevalência do fenômeno de Raynaud entre operadores de ferramentas vibratórias em comparação aos não expostos, com aumento do número de casos quanto maior o nível de vibração e tempo de exposição. O frio é fator desencadeante e agravante do fenômeno de Raynaud e parece exercer papel importante para o surgimento das manifestações vasculares da síndrome de vibração de mãos e braços.

Carcinogens that induce the A:T > T:A nucleotide substitutions in the genome / 医学前沿

Recently, Ng et al. reported that the A:T > T:A substitutions, proposed to be a signature of aristolochic acid (AA) exposure, were detected in 76/98 (78%) of patients with hepatocellular carcinoma (HCC) from the Taiwan Province of China, and 47% to 1.7% of HCCs from the Chinese mainland and other countries harbored the nucleotide changes. However, other carcinogens, e.g., tobacco carcinogens 4-aminobiphenyl and 1,3-butadiene, air toxic vinyl chloride and its reactive metabolites chloroethylene oxide, melphalan and chlorambucil, also cause this signature in the genome. Since tobacco smoke is a worldwide public health threat and vinyl chloride distributes globally and is an air pollutant in Taiwan Province, the estimation of the patients' exposure history is the key to determine the "culprit" of the A:T > T:A mutations. Apparently, without estimation of the patients' exposure history, the conclusion of Ng et al. is unpersuasive and misleading.

Non-cirrhotic portal hypertension in an ankylosing spondylitis patient / 영남의대학술지

Idiopathic non-cirrhotic portal hypertension (INCPH) is a disease with an uncertain etiology consisting of non-cirrhotic portal hypertension and portal pressure increase in the absence of liver cirrhosis. In INCPH, patients exhibit normal liver functions and structures. The factors associated with INCPH include the following: Umbilical/portal pyremia, bacterial diseases, prothrombic states, chronic exposure to arsenic, vinyl chloride monomers, genetic disorders, and autoimmune diseases. Approximately 70% of patients present a history of major variceal bleeding, and treatment relies on the prevention of complications related to portal hypertension. Autoimmune disorders associated with INCPH are mainly systemic sclerosis, systemic lupus erythematosus and rheumatoid arthritis. To the best of our knowledge, a case of ankylosing spondylitis (AS) associated with INCPH has not been reported thus far. Therfore, we report our experience of a patient with AS accompanied by INCPH, who showed perisplenic varices with patent spleno-portal axis and hepatic veins along with no evidence of cirrhosis on liver biopsy, and provide a brief literature review.

Determination of thiodiglycolic acid in urine with gas chromatography-mass spectrometer / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To establish a rapid determination method with gas chromatography-mass spectrometer (GC-MS) for thiodiglycolic acid (TDGA), a vinyl chloride (VCM) biomarker.</p><p><b>METHODS</b>A high- sensitivity determination method was established using a moderate methyl esterification instead of methyl esterification of highly toxic diazo reaction.</p><p><b>RESULTS</b>The standard curve regression linear equation of the method was: y=8460.5x-4758.2, the linear coefficient was 0.999 7, the minimum quantity concentration was 2.0 µg/L, the range of precision value was 0.81%-2.38%, and the average recovery of standard addition was 99.0%-102.9%.</p><p><b>CONCLUSION</b>This method reduces the risk of traditional methyl esterification, improves the determination sensitivity compared with the GC-FPD method, and meets the determination requirement of TDGA.</p>

The serumproteomics research of vinyl chloride workers / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To screen out serum differential proteins between vinyl chloride monomer (VCM)-exposed workers and healthy controls by proteomics and analyze the functions of differential proteins, and to provide a basis for elucidating the pathogenesis of diseases caused by VCM exposure and searching for the protein biomarkers.</p><p><b>METHODS</b>Fasting venous blood was collected from 125 VCM-exposed workers and 40 healthy controls according to accumulated exposure doses. Proteins were precipitated by acetone precipitation. These proteins were identified by 2D-nano LC-ESI-TOF/MS and quantified by isobaric tags for relative and absolute quantitation. The functions of differential proteins were analyzed by gene ontology.</p><p><b>RESULTS</b>A total of 596 proteins were identified, including 194 quantified proteins. There were 21 differential proteins according to the screening criteria (19 upregulated proteins and 2 downregulated proteins), including complement, apolipoprotein, and glycoprotein. The functions of these differential proteins were binding, enzyme regulator activity, catalytic activity, and transporter activity, and they were involved in the biological processes including immune system process and response to stimulus.</p><p><b>CONCLUSION</b>The complement, apolipoprotein, and glycoprotein identified in the proteomics may be related to liver injury caused by VCM exposure, and they could be used as candidate protein biomarkers of diseases caused by VCM exposure.</p>

Effects of polymorphisms in XRCC1 and APE1 on vinyl chloride-induced chromosome damage / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To evaluate the effects of polymorphisms in XRCC1 and APE1 genes on vinyl chloride (VC)-induced chromosomal damage in peripheral lymphocytes.</p><p><b>METHODS</b>In this study, 317 workers occupationally exposed to VC were recruited from a factory in Shandong Province, China. The micronucleus (MN) frequency in peripheral lymphocytes was used as an indicator of chromosomal damage. Polymerase chain reaction-restriction fragment length polymorphism and created restriction site combined with restriction fragment length polymorphism were used to determine the five single nucleotide polymorphisms in XRCC1 and APE1 genes in the base excision repair pathway. The association of chromosomal damage with these polymorphisms and the haplotype of XRCC1 was analyzed using Poisson regression and PHASE 2.0.2.</p><p><b>RESULTS</b>It was found that among the VC-exposed workers, individuals with XRCC1 polymorphisms (-77C/T, Arg194Trp, Arg280His, and Arg399Gln) had a significantly higher MN frequency than those with homozygous wild-type genotypes, with frequency ratios (FR) as follows, respectively: FR = 1.21, 95%CI: 1.05∼1.39 (P < 0.05); FR = 1.14, 95%CI: 1.00∼1.38 (P < 0.05); FR = 1.26, 95%CI: 1.11∼1.44 (P < 0.05); FR = 1.23, 95%CI: 1.08∼1.46 (P < 0.05). APE1 Asp148Glu was found of no significant relationship with MN frequency. Haplotype analysis of XRCC1 demonstrated that the MN frequencies in subjects with CTAA/CTAA and CCAA/CTAA were significantly higher than that in those with TCGG/TCGG (FR = 1.19, 95%CI: 1.02∼1.32, P < 0.05; FR = 1.41, 95%CI: 1.02∼1.87, P < 0.05). Furthermore, association was found between accumulated exposure to VC and XRCC1 polymorphisms (-77C/T, Arg194Trp, Arg280His, and Arg399Gln) after adjustment for age, sex, drinking, and smoking.</p><p><b>CONCLUSION</b>VC can induce chromosomal damage even when the exposure level is lower than the national occupational health standard of China (PC-TWA: 10 mg/m(3)); the polymorphisms in XRCC1 and APE1 are associated with chromosomal damage induced by VC.</p>

Compensation for Work-Related Hematologic, Liver, and Infectious Diseases

Occupational diseases may be defined only medically or scientifically, and even then, their definition is not simple. However, compensable occupational diseases involve the additional layer of legal systems and social welfare policies as well. Their multifaceted nature makes determining the work-relatedness of these diseases more complex. Korea has established standards for the recognition of occupational diseases in Schedule 5 of the Enforcement Decree of the Labor Standards Act, and specific criteria for the recognition of occupational diseases are listed in Schedule 3 of the Enforcement Decree of the Industrial Accident Compensation Insurance Act. The new list of compensable occupational diseases comprises 13 articles as an open-ended system. The newly added articles pertain to lymphohematopoietic (Article 5) and infectious diseases (Article 9), as well as diseases of other target organs. Furthermore, the article on liver diseases (Article 8) has been partially revised. The new act has been changed to clarify the meaning as it has been presented in recent research. It is necessary to achieve agreement among concerned parties, including experts from the legal, medical, and social domains to resolve the issues of work-relatedness, causation, notion of aggravation, and so on for preparing a list and a process that are more reasonable.

Susceptibility of chromosomal damage among workers exposed to vinyl chloride monomer / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the association between chromosomal damage induced by vinyl chloride monomer (VCM) and polymorphisms of xenobiotic metabolism genes and DNA repair genes.</p><p><b>METHODS</b>Cytokinesis-block micronucleus (CBMN) test was performed to detect chromosomal damage in peripheral lymphocytes of 402 VCM-exposed workers. Multiplex PCR was used to simultaneously amplify GSTM1 and GSTT1 genes, other genetic polymorphisms were performed using a PCR-RFLP technique.</p><p><b>RESULTS</b>Multiple (adjusted) Poisson regression analysis showed that mean MN frequencies were significantly elevated for the intermediate (4000-40000 mg) and high (> 40000 mg) exposure groups as compared with the low exposure group (P = 0.003 and 0.03, respectively). For genetic polymorphisms, the exposed workers with CYP2E1 or XRCC1 Arg280His variance showed a higher CBMN frequency than their wild-type homozygous counterparts (P = 0.02); so did the workers with GSTP1 105Val/Val genotype or ALDH2 504Glu/Glu genotype than those with a combination of other genotypes (P = 0.01 and 0.003, respectively).</p><p><b>CONCLUSION</b>Our findings reveal that cumulative exposure dose of VCM and common genetic variants in genes, such as GSTP1, CYP2E1, ALDH2, XRCC1 Arg280His genotypes, are the major factors that modulate MN induction in VCM- exposed workers. Further study to investigate the relationship between individual characteristics and genetic susceptibility to VCM-caused chromosome damage is warranted, it is helpful for us to understand the mechanism of VCM metabolism, to find the biomarkers of susceptibility and to recognize the susceptible individuals in the primary prevention of VCM-caused damage.</p>

Genetic susceptibility of DNA damage induced by vinyl chloride monomer exposure / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the association between DNA damage induced by vinyl chloride monomer (VCM) and polymorphisms of DNA repair genes and xenobiotic metabolism genes of VCM.</p><p><b>METHODS</b>Comet assay was employed to detect DNA damage. Based on the status of DNA damage, the VCM exposure workers were divided into two groups: DNA damage group (75) and control group (75). Case-control design was used to investigate the association between the genetic polymorphisms and DNA damage induced by VCM. Genotypes of XRCC1 (Arg194Trp, Arg280His and Arg399Gln), XPD (Ile199Met, Asp312Asn and Lys751Gln) and CYP2E1 were identified by the PCR-RFLP. PCR assay was used to detect positive and null genotype of GSTT1 and GSTM1.</p><p><b>RESULTS</b>Univariate analysis showed that the CYP2E1 c1c2/c2c2 and XPD751 Lys/Gln and Gln/Gln genotypes were significantly associated with the increased levels of DNA damage, XRCCI 339 Arg/Gln and Gln/Gln genotypes were significantly associated with the decreased levels of DNA damage (P < 0.01, P < 0.05, respectively). Logistic regression analysis showed that there was significant association between the genotypes of XRCC1 194, XRCC1 399, XPD 751, CYP2E1 and DNA damages. A prominent risk decreasing of DNA damage was observed for those individuals possessing XRCC1 399Arg/Gln + Gln/Gln genotypes (OR: 0.35, 95%CI: 0.12 approximately 1.01, respectively); The results also showed that there were significant associations between CYP2E1 c1c2/c2c2 and DNA damage both in high and low VCM-exposed groups (OR: 2.57, 95%CI: 1.01 approximately 6.59 and OR: 2.57, 95%CI: 0.99 approximately 6.87).</p><p><b>CONCLUSION</b>Cumulative exposure dose and genotypes of XRCC1 194, XRCC1 399, XPD 751 and CYP2E1 may modulate the DNA damage induced by VCM exposure.</p>

Fenómeno de Raynaud por exposición a cloruro de vinilo / Raynaud's phenomenon secondary to vinyl chloride exposure

El policloruro de vinilo (PVC) es el polímero que ocupa el tercer puesto en el mercado de producción de plásticos a nivel mundial. Como consecuencia de la exposición crónica, los operarios pueden desarrollar cambios óseos degenerativos, Raynaud, trastornos circulatorios en extremidades, trombocitopenia y lesiones cutáneas semejantes a esclerodermia; esto se conoce como “enfermedad por cloruro de vinilo”. Presentamos un paciente masculino de 24 años de edad que presenta fenómeno de Raynaud, cefaleas, malestar en manos y pies, sensación de frío, fatiga y pérdida de apetito asociado a exposición a policloruro de vinilo. El estudio de la microcirculación cutánea periungueal por videocapilaroscopía muestra alteraciones estructurales y funcionales características. Se recomienda un seguimiento multidisciplinario estricto de los trabajadores expuestos a PVC.

Effect of vinyl chloride on reproductive and endocrine system of male rats / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the effect of vinyl chloride on reproductive and endocrine system of male rats.</p><p><b>METHODS</b>Male SD rats were administered with vinyl chloride at dose of (0, 10, 100, 1000 mg/kg) for 14 and 28 days, respectively. The levels of testosterone (T), inhibin B, luteinizing hormone (LH), follicle stimulating hormone (FSH) and estradiol (E2) were measured in serum and testis homogenates. Histopathological examinations were performed for testis with electron microscopy.</p><p><b>RESULTS</b>Compared with the control group after 14-day exposure, T and E2 serum levels of 1000, 100, 10 mg/kg groups decreased, InhB and LH levels of three dose groups increased. LH serum levels of 100 mg/kg increased significantly statistically compared with control group (P < 0.05). After 28-day exposure, T serum levels of 100, 1000 mg/kg groups were (10.90 +/- 1.56), (8.52 +/- 2.85) ng/ml respectively (P < 0.05), InhB serum levels of 100, 1000 mg/kg groups were (31.40 +/- 6.21), (28.39 +/- 5.67) pg/ml respectively. Both of T and InhB serum levels of 100, 1000 mg/kg groups decreased significantly (P < 0.05). Serum FSH levels of 10, 100, 1000 mg/kg groups decreased significantly compared with control group (P < 0.05). Compared with groups of 14-day exposure, serum InhB and LH levels of 10, 100, 1000 mg/kg groups decreased significantly statistically after 28 days. T and InhB testis levels of 100, 1000 mg/kg groups were 8.05 +/- 2.19),(6.75 +/- 1.94) ng/mg pro and (39.32 +/- 5.55), (35.53 +/- 8.71) pg/mg pro respectively, which decreased significantly compared with control group (P < 0.05). Leydig cell and Sertoli cell were damaged according to histopathological examinations.</p><p><b>CONCLUSION</b>Vinyl chloride has adverse effects on reproductive and endocrine system of male rats and may change their serum and testis homogenate levels of hormones.</p>

Genetic polymorphism in cell cycle control genes and susceptibility of chromosomal damage in vinyl chloride monomer exposed workers / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the relationship between genetic polymorphism of P53, P21, CCND1 and susceptibility of chromosomal damage induced by vinyl chloride monomer (VCM).</p><p><b>METHODS</b>183 workers occupationally exposed to VCM were involved in our study. Cytokinesis-block micronucleus (CB-MN) assay was used to detect chromosome damage in peripheral lymphocyte. PCR-RFLP technique was applied to detect polymorphisms in P53 gene (exon4, intron3 and intron6), P21 gene (exon2 and exon3) and CCND1 (exon4).</p><p><b>RESULTS</b>The risk of chromosomal damage for VCM-exposed workers with more than 30 yr was 1.2202 (95% CI: 1.0580 approximately 1.4072, P = 0.0062) compared with the younger workers, and the risk of female workers was 1.1491 (95% CI: 0.9841 approximately 1.3416, P = 0.0772) compared with male workers. The MN frequency in subjects with P53 intron6 mutant homozygous and heterozygous was higher than their wild-type homozygous counterparts (OR = 1.3032, 95% CI: 1.1285 approximately 1.6405, P = 0.0285). P53 exon4, intron3 and intron6 haplotype pairs of BBB/AAA and BAB/AAA were associated with the increased frequencies of micronucleus.</p><p><b>CONCLUSION</b>Among VCM-exposed workers, more than 30ys, female, carrying P53 intron6 mutated allele and BBB/AAA and BAB/AAA haplotype pairs have higher risk of chromosomal damage.</p>

Urinary Excretion of Thiodiglycolic Acid According to Sampling Time in Workers Exposed to Vinyl Chloride Monomer / 대한산업의학회지

OBJECTIVES: The study was performed to investigate the changes of urinary thiodiglycolic acid (TDGA) concentration in workers exposed to vinyl chloride monomer (VCM) according to the time of sampling urine. METHODS: The personal exposure to airborne VCM was assessed and urinary TDGA concentration was sampled in 31 workers employed in a VCM and polyvinyl chloride (PVC) manufacturing factory. Urinary TDGA was sampled three times: before the start of the shift after 3 days off (TDGA1), after the end of the first-day shift (TDGA2) and before starting the following day shift after completing the oneday shift (TDGA3). Urinary TDGA in 30 workers who had not been exposed to airborne VCM was sampled after the end of the shift. A gas chromatography/pulsed flame photometric detector (GC/PFPD) was utilized to analyze TDGA concentration in urine after the urine was methylated with trimethylsilyldiazomethane(2.0M in diethyl ether). RESULTS: The creatinine level was 0.179+/-0.271 mg/g in the control workers and 0.218+/-0.443 mg/g in the workers before the start of the shift after 3 days off (TDGA1), showing no significant difference (p=0.7035). Urine samples were compared according to sampling time in order to investigate the change of urinary TDGA concentration in the case of continuous exposure to airborne VCM. In VCM-exposed workers, urinary creatinine concentration was 0.434+/-0.623 mg/g in TDGA2 and 0.767+/-1.056 mg/g in TDGA3, which indicated a gradual but significant increase (p=0.024). In terms of the statistical correlation between airborne VCM and urinary TDGA to evaluate exposure dose per day, of the three urinary TDGA concentrations, TDGA3 showed the highest degree of regression (R(2)=0.4215) with 8h-TWA airborne VCM concentration. CONCLUSION: Based on this result, the excretion half-life of urinary TDGA was assumed to be less than 3 days, because the concentration of urinary TDGA at 3 days after exposure to airborne VCM was decreased to the level of urinary TDGA concentration in the control workers. The concentration of urinary TDGA increased in the case of continuous shift, due to the accumulation of residual metabolites of TDGA. It was considered that TDGA3 can be applied as a useful biological index to evaluate the exposure dose of airborne VCM during one day because TDGA3 showed the highest correlation with the exposure dose of airborne VCM in the previous shift day.

Some topographical and morphological studies on air sacs of domestic pigeon [Columba livia domestica] using corrosion casts

The work was carried out on fifteen adult pigeons of both sexes. The gross morphological features of the air sacs were thoroughly investigated using Vinyl chloride acetate corrosion casts. It was found that the pigeon as an example of a powerful flying bird had 4 pairs of transparent air sacs [cervical, cranial thoracic, caudal thoracic and abdominal], in addition to an unpaired interclavicular sac. They were symmetrically occupying either side of the body cavity. The cervical sacs aerated the cervical vertebrae approximately from the 3rd or 4th as well as the first two thoracic vertebrae. The single interclavicular air sac was the most complicated among all air sacs in the pigeons. It occupied the ventral part of the thoracic inlet and overlay the cervical sacs laterally and connected with their cranial ends. Meanwhile, the interclavicular sac gave off extrathoracic humeral and axillary diverticula, which pneumatized the humeri and bones of the pectoral girdles. It was also observed that the cranial and caudal thoracic air sacs showed no bony communications, and never aerates bones. The paired abdominal sacs were larger than the other air sacs. They enclosed between their medial surfaces the intestinal tract, kidneys and the gonads. Also, each of them sent a diverticulum which ventilated the interior of the pelvic bone and the synsacrum. The obtained results of the air sacs in the pigeon were discussed with the findings given by previous authors in other species of birds

A Case of Hepatic Angiosarcoma Presenting as Submucosal Tumor Resulting from Gastric Invasion / 대한소화기내시경학회지

Angiosarcoma accounts for 1% of all soft tissue sarcoma. Common sites of occurrence include the skin, breast, soft tissue, and liver. It metastasizes to the lungs, bone, and spleen. The cause of hepatic angiosarcoma in the 60% of cases is unknown, although specific risk factors such as vinyl chloride, arsenic, thorotrast and external-beam irradiation have been identified. Since 1986, about eight cases of hepatic angiosarcoma have been reported in Korea, but it had not been reported in which the hepatic angiosarcoma invaded to the stomach, yet. So we report a case of histopathologically confirmed primary hepatic angiosarcoma with gastric involvement. In this case, a sixtythree-year-old female was presented with indigestion and epigastric soreness for 1 year. Endoscopic examination of the stomach revealed a submucosal tumor-like protruding mass from the antrum to angle. The mucosal surface showed severe hyperemia and shallow ulcerative change was seen. Endoscopic biopsy and percutaneous liver biopsy confirmed the diagnosis of hepatic angiosarcoma invading the gastric wall.

DNA damages of liver cells and expressions of DNA damage repair genes in rats exposed to vinyl chloride monomer / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study DNA damages of liver cells in rats exposed to vinyl chloride monomer (VCM), and the expressions of DNA damage repair enzymes including O(6)-methyl guanine-DNA methyl transferase (MGMT), X-ray repair cross-complementing group 1 (XRCC1) and X-ray repair cross-complementing group 3 (XRCC3); and to explore the repair mechanism of DNA damage induced by VCM.</p><p><b>METHODS</b>Rats were exposed to VCM by intraperitoneal injection. DNA damages were detected by single cell gel electrophoresis (comet assay). The expressions of DNA damage repair enzymes were measured by immunohistochemical methods.</p><p><b>RESULTS</b>The percentages of comet cells in low, moderate, and high dose groups (11.75%, 12.38%, and 17.63%, respectively) were greater than that of control (5.67%). The latter two groups were significantly different from that of control (P < 0.05, P < 0.01). The expressions of MGMT and XRCC1 decreased, and XRCC3 increased with the dose of VCM increased. DNA damage was correlated with the expression of XRCC3 (r = 0.438, P = 0.067).</p><p><b>CONCLUSION</b>VCM can cause DNA damage of liver cells with dose-response relationship. DNA damage repair enzymes take part in the repairing of DNA damage induced by VCM.</p>

Evaluation method for vinyl chloride exposed workers

BACKGROUND: This study was conducted to evaluate vinly chloride exposure in vinyl chloride and poly vinyl chloride manufacturing factories. The object of this study was compare two different type of air sampling method that of, NIOSH and OSHA recommended and Investigate quantitative correlation between level of vinyl chloride exposure and urinary thiodiglycolic acid excretion. METHODS: Air sampling was conducted by two method and sampling mediums were located at workers breathing zone in the same location. Sampling mediums were changed in 60 minute interval and sampling pumps were recalibrated at the same time. Urine was collected before and end of shift were stored frozen and determined by GC/FID analysis. RESULTS: In NIOSH method, time weighted average was 3.562 +/- 2.898 ppm and OSHA method time weighted average was 4.051 +/- 3.700 ppm. Concentration of urinary TdGA in before shift was 0.527 +/- 0.828 g/g creatinine and end of shift was 4.190 +/- 7.665 mg/g creatinine. Difference of urinary TdGA between end of shift to before shift was 3.662 +/- 7.865 mg/g creatinine. In NIOSH method, correlation coefficient between 8hour-time weighted average (8hrs-TWA) and urinary concentration of TdGA was r=0.666. and last period vinyl chloride level (6th-TWA) and urinary TdGA concentration was r=0.972. In OSHA method, correlation coefficient between last period vinyl chloride level (6th-TWA) and urinary concentration of TdGA was r=0.976 and this was highest value. CONCLUSION: There was no statistically significant difference in NIOSH method and. OSHA method. A correlation were found between level of vinyl chloride exposure and urinary thiodiglycolic acid excretion. Also, vinyl chloride exposure had significantly effected on the urinary thiodiglycolic acid excretion.

The variation of thiodiglycolic acid concentration in urine with vinyl chloride exposure levels in rats / 대한산업의학회지

OBJECTIVES: It is the objective of this research to identify the variation of thiodiglycolic acid (TdGA) in urine with vinyl chloride monomer (VCM) exposure levels through methylation. METHODS: After rats were exposed to vinyl chloride monomer of 4 levels, 0 mg/m3, 50 mg /m3, 150 mg/m3, 500 mg/m3, respectively, of which urine was sampled in each sampling time of 0 hour, 2 hours, 4 hours, 8 hours, 16 hours, 24 hours, 36 hours, 48 hours. After urine had been methylated with diazomethane in the preliminary experiment and the peak of 146 m/z had been verified, the main experiment was done. RESULTS: In the variation of TdGA with sampling times, concentration of TdGA increased rapidly in 4 hours and then decreased after 8 hours. When the variation of urinary .TdGA concentration in urine according to exposure level of VCM was verified through Kruskal-Wallis statistical method at each sampling time, the significant increment with the exposure levels at 2 hours, 4 hours, 8 hours after exposure was clarified. CONCLUSION: TdGA concentration in urine with increment of VCM exposure level increased, especially significantly at 2 hours, 4 hours, 8 hours of sampling time.