• Toxicological Research
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• v.19 no.4
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• pp.267-275
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• 2003

The purpose of our study was to evaluate the toxicity of the thimerosal in embryos and neonates. Thimerosal (also known as mercurothiolate) is a mercury-containing compound used in trace amounts to prevent bacteria and other organisms from contaminating vaccines, especially in opened multi-dose vials. The toxicity of mercury is well known and those most at risk occurrs in unborn babies and newborn babies. Test methods included in vitro whole embryo culture (WEC) system and in vivo test of neonatal toxicity in Wistar rats. Ethylmercury and methylmercury were used as positive controls for the evaluating of toxic effects of mercury. In WEC assay, treated concentrations of thimerosal, ethylmercury and methylmercury were up to 0.01, 0.025, 0.05, 0.1, 0.25, 0.5, 1, 2.5 and 5 $\mu\textrm{g}$/$\textrm{m}{\ell}$, respectively. All compounds didn't show any morphological abnormalities, but showed retardation of growth and development in dose dependent manner (> 0.5 $\mu\textrm{g}$/$\textrm{m}{\ell}$). These data indicated that thimerosal showed developmental toxicity in vitro. In vivo neonatal toxicity, Wistar rats were administered subcutaneously with thimerosal, ethyl mercury, or methylmercury (5, 25, 50, 250, and 500 $\mu\textrm{g}$/kg) during from postnatal day (PND) 4 to 25. Significant effects of these compounds on relative organ weights and organ morphology were not observed in this experiment. However, accumulation of mercury was detected in the kidney and testis when treated with thimerosal, ethylmercury, or methylmercury. These results suggest that thimerosal may be a harmful compound to embryo and neonate, but used concentration of thimerosal in these experiments is much higher than that of clinical application. Further investigation is needed on the safety of vaccine components, i.e. a thimerosal using in vitro and in vivo tests in the future.

• Environmental Mutagens and Carcinogens
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• v.22 no.4
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• pp.229-235
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• 2002

Thimerosal, a widely used preservative, has been well known to induce intracellular calcium mobilization in various cell types. However, the mechanism of its calcium mobilization is not clearly understood yet. For studying the mechanism of thimerosal-mediated calcium release, we have used HL60 cells in calcium-free Lockes solution that has no extracellular calcium. Thimerosal significantly reduced the lag period of initial calcium release whereas it enhanced the rate and magnitude of the calcium release in a dose-dependent manner. At the same time, we found that thimerosal generated superoxide anion by activating NADPH oxidase in dose- and time-dependent manner. Interestingly, the kinetics and the dosedependency of superoxide anion generation were very similar to those of intracellular calcium mobilization. In inhibitors study, the thimerosal-induced superoxide anion generation was significantly suppressed by DMSO as well as superoxide dismutase but not by genistein or EGTA. Surprisingly, the pretreatment with N-Acetyl-$_{L}$-Cysteine blocked almost completely the thimerosal-induced calcium increase, indicating that ROS playa key role in the calcium mobilization. The present results suggest that thimerosal-induced calcium mobilization is possibly mediated by the activation of NADPH oxidase and subsequent ROS generation.n.

• Korean Journal of Veterinary Research
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• v.16 no.2
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• pp.165-171
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• 1976

Experimental approaches on the effectiveness of thimerosal to control growth of Nosema apis (Zander, 1909) were carried out in the rearing honey bees. The rearing honey bees were artificially infected with various levels of spore isolated from local honey bees. The results obtained were summarized as follows: 1. In the experiments of therapeutic chemicals for Nosema disease, 0.01% and 0.02% thimerosal of sucrose-honey mixture was the most effective agent but the each concentration of amprolium, furazolidone, hygiene, sulfadimethoxine and terramycin did not show the any effects 2. It showed very high therapeutic effectiveness (over than 90%) that the treatment of three times every other day after the treatment of three times consecutive every day with 0.01% thimerosal, or the treatment of three times consecutive every day with 0.02% thimerosal. 3. When 0.02% thimerosal was administered three times consecutive every day to honey bees at the 4th day before artificial inoculation of N. apis, it showed very high degree (100%) of prevalence control effectiveness, and it also showed high degree (over than 90%) in administration at the 7th day before, and over than 80% at the 10th day before. Then authors found that thimerosal has the prevalence control effectiveness as well as the treatment effectiveness. 4. In the rearing honey bee colony, 0.02% thimerosal showed the high degree (over than 80%) of therapeutic effectiveness with the various levels which contained from the light decree of infection to the severe degree of it.

• Proceedings of the Korean Society of Toxicology Conference
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• 2002.05a
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• pp.71-72
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• 2002

Thimerosal is a mercury-containing compound used in trace amounts to prevent bacteria and other organisms from contaminating vaccines, especially in opened multi-dose vials. The toxicity of mercury is well known and those most at risk are occurred in unborn and newborn babies.(omitted)

• YAKHAK HOEJI
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• v.55 no.4
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• pp.284-288
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• 2011

The test method for biologics of lot release system is based on 'Test procedure and specification for biological products,' generally, thimerosal content is measured by chemical analysis using O.D. In this study, the comparative analysis was carried out using the gold amalgamation method for thimerosal content was compared to the existing methods, which are described above. The gold amalgamation method, which uses atomic absorption spectrophotometry, was meets all the method validation acceptance criteria. It is considered to be proper as the assay and identification test for thimerosal. In this study, the comparative analysis was performed three times. As a result, gold amalgamation method is more convenient and easy to perform as this assay doesn't have pre-treatment procedure. Also this assay showed good precision and reproducibility compared to the conventional method. Therefore, it is appropriate to alternate the assay method of thimerosal from the conventional chemical analysis to gold amalgamation method to improve the credibility of lot release system and the quality control of biologics, by standardizing test method.

• Proceedings of the Korea Environmental Mutagen Society Conference
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• 2002.05a
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• pp.71-72
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• 2002

• Journal of Microbiology and Biotechnology
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• v.19 no.12
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• pp.1582-1589
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• 2009

Bacterial UDP-N-acetylglucosamine enolpyruvyl transferase (MurA) catalyzes the transfer of enolpyruvate from phosphoenolpyruvate (PEP) to uridine diphospho-N-acetylglucosamine (UNAG), which is the first step of bacterial cell wall synthesis. We identified thimerosal, thiram, and ebselen as effective inhibitors of Haemophilus influenzae MurA by screening a chemical library that consisted of a wide range of bioactive compounds. When MurA was preincubated with these inhibitors, their 50% inhibitory concentrations ($IC_{50}s$) were found to range from 0.1 to $0.7\;{\mu}M$. In particular, thimerosal suppressed the growth of several different Gram-negative bacteria such as Escherichia coli, Pseudomonas aeruginosa, and Salmonella typhimurium at a concentration range of $1-2\;{\mu}g/ml$. These inhibitors covalently modified the cysteine residue near the active site of MurA. This modification changed the open conformation of MurA to a more closed configuration, which may have prevented the necessary conformational change from occurring during the enzyme reaction.

• Journal of Pharmaceutical Investigation
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• v.27 no.2
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• pp.99-108
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• 1997

To evaluate the feasibility of mucosal delivery of thyrotropin releasing hormone (TRH) through various mucosae, enzymatic degradation and stabilization of TRH in the nasal, rectal and duodenal extracts of rabbits were studied. TRH in the extracts was assayed by HPLC and its degradation was found to follow apparent first-order kinetics. The residual concentrations of TRH in the mucosal extracts of nasal, rectal and duodenal segments after 24 hr of incubation were found to be $65.1({\pm}1.1),\;19.7({\pm}2.7)$ and 0%, and in the serosal extracts, $65.6({\pm}5.5),\;75.2({\pm}1.1)$ and $68.7({\pm}1.4)%$, respectively. This result suggests that there is a significant difference in the activity of TRH-degrading enzymes among the sites of administration. The inhibition of TRH degradation in the mucosa extracts was kinetically investigated using various additives such as thimerosal, benzalkonium chloride, disodium edetate, ${\sigma}-phenanthroline$, dithiothreitol and dithioerythritol, and $IC_{50}$ values of inhibitors were calculated. The results obtained showed that thimerosal (0.5 mM) and benzalkonium chloride (0.141 mM) protected TRH from the enzymatic degradation in all the mucosa extracts more than 95% after 24 hr of incubation.

• Journal of Pharmaceutical Investigation
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• v.24 no.1
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• pp.1-9
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• 1994

In order to study systemic peptide delivery through the ocular route, the stabilities of methionine enkephalin (Met-Enk) and $[D-ala^2]-methionine$ enkephalinamide (YAGFM) in the corneal extracts of rabbits were investigated using reversed phase HPLC. Met-Enk was found to be hydrolyzed most rapidly in the corneal epithelium, but YAGFM was relatively stable. Aminopeptidases appeared to contribute over 60% to the degradation of Met-Enk and the degradation rate of Met-Enk followed the first order kinetics. The half-lives of Met-Enk in the extracts of the corneal epithelium and endothelium were 36 and 673 min, respectively. From the effects of enzyme inhibitors, it was found that the application of the mixture of amastatin, thimerosal and EDTA was very useful for the inhibition of peptide degradation.

• Proceedings of the Korean Society of Applied Pharmacology
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• 1993.04a
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• pp.178-178
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• 1993

생리활성 펩타이드류의 경점막 수송을 검토하기 위하여 토끼의 비강, 직장, 질 또는 눈 점막 구출액에서의 메치오닌엔케팔린 (Met-Enk) 및 그 합성 유사체인 [D-알라$^2$]-메치오닌엔케팔린아미드 (YAGFM)의 효소적 분해를 억제하고자 수종 효소억제제를 검토하였다. 방법: 토끼의 질, 직장 및 비강 점막을 차례로 적출하여 신속히 Valia-Chien투과셀에 마운팅하고, 눈의 각막은 절취하여 따로 각막 투과셀에 마운팅한 다음 등장 인산염 완충액 3.5ml씩으로 8시간씩 3회 추출하여 점막측 및 장막측 추출액을 제조하였다. 추출 완료 직후 이들 추출액에 Met-Enk 또는 YAGFM 50$\mu\textrm{g}$/ml의 농도로 첨가하고 여러 효소억제제를 단독 또는 혼합하여 첨가한 조건에서 37$^{\circ}C$에서 60 rpm으로 24시간 동안 흔들면서 경시적으로 시료를 취하여 잔존 펩타이드의 양을 HPLC법으로 정량하여 속도론적으로 비교 검토하였다. 이 연구에 사용한 효소억제제로는 아미노펩티다제의 억제제인 amastatin (AM), bestatin (BS). 엔케팔리나제 A의 억제제로 알려진 thiophan (TP), 엔케팔리나제 B의 억제작용이 있는 것으로 밝혀진 thimerosal (TM), metalloenzyme의 억제제인 에데트산나트륨 (EDTA) 등을 검토하였고 또 $\beta$-시클로덱스트린 유도체인 디메칠-$\beta$-시클로덱스트린과 2-히드록시프로필-$\beta$-시클로덱스트린이 펩타이드의 분해억제효과도 함께 검토하였다.