Zhenlin Xie

Ovarian toxicity of 2-bromopropane in the non-pregnant female rat

Ovarian Toxicity of 2‐Bromopropane in the Non‐Pregnant Female Rat: Michihiro Kamijima, et al. Department of Hygiene, Nagoya University School of Medicine—A cluster of patients with amenorrhea, oligospermia and anemia were found among workers in an electronics factory in the Republic of Korea. 2‐Bromopropane was suspected to cause the disorders. This study aimed to clarify its ovarian toxicity in the virgin rat. Female Wistar rats were daily exposed to 0, 100, 300, or 1,000 ppm 2‐bromopropane for eight hours a day for 9 weeks. During the experimental period, vaginal smears were taken everyday to monitor ovarian cyclicity. Tissues were histopathologically examined and plasma concentrations of luteinizing hormone (LH) and follicle‐stimulating hormone (FSH) were determined at the end of experiment. The vaginal smear test showed that the number of normal cycles decreased significantly both in the 300 and 1,000 ppm groups. The histopathological examination revealed dose‐dependent ovarian follicle atresia accompanied by a decreased number of normal antral and growing follicles in the 300 and 1,000 ppm groups. Especially, in the ovaries of rats with persistent estrous smears in the 1,000 ppm group, most of the follicles were atretic and there were no newly formed corpora lutea. There still remained normal antral follicles and corpora lutea in the ovaries of the remaining rats of the group and of the 300 ppm group with constant diestrous and occasional estrous smears. Hormonal examination revealed no statistically significant change in LH or FSH concentrations between any groups. The results showed that 2‐bromopropane has ovarian toxicity in rats, indicating that the secondary amenorrhea in human cases was due to 2‐bromopropane exposure.

Effect of inhalation exposure to 2-bromopropane on the nervous system in rats

Exposure to 2-bromopropane (2-BP) is suspected to have adverse effects on the nervous system. The aim of this study was to investigate whether the exposure of rats to 2-BP had neurotoxic effects using histological and electrophysiological studies. Wistar strain male rats were exposed daily to either 100 or 1000 ppm 2-BP or to fresh air for 8 h a day for 12 weeks. Body weight was measured before exposure and every 2 weeks. Motor nerve conduction velocity (MCV) and distal latency (DL) were measured before exposure and every 4 weeks during exposure. Histological examination of the nervous system was also performed. Exposure of rats (n = 9) to 1000 ppm resulted in suppression of body weight gain and a significant decrease in brain weight compared to the control (n = 9). Electrophysiological measurements showed a significant decrease in MCV in 1000 ppm exposed rats at 8 weeks and significant prolongation of DL at 8 and 12 weeks. Abnormalities of the myelin sheath were detected in the common peroneal nerves. In 100-ppm exposed rats (n = 9), no significant changes were noted in body weight and the peripheral nerve. In conclusions, long-term exposure to 1000 ppm of 2-BP may result in peripheral neuropathy in rats.

Experimental study on phototoxicity and the photosensitization potential of ketoprofen, suprofen, tiaprofenic acid and benzophenone and the photocross‐reactivity in guinea pigs

Background: Ketoprofen, suprofen and tiaprofenic acid are arylpropionic anti‐inflammatories. Their chemical structures share the same elements as the benzoyl radical and the tiophene ring. We experienced nine cases of ketoprofen photoallergy, seven cases of suprofen photoallergy and three cases of tiaprofenic photoallergy.

Experimental study on skin sensitization potencies and cross‐reactivities of hair‐dye‐related chemicals in guinea pigs

In screening patch testing of hairdressers with occupational contact dermatitis, multiple positive reactions to hair dye‐related chemicals, such as p‐phenylenediamine (PPD), p‐toluenediamine ·  2HCI (PTD) and p‐aminophenol (PAP), a fabric dye p‐aminoazobenzene (PAB), and a tar dye Sudan III, were frequently encountered. To investigate individual skin sensitization potency and the cross‐reactivities among above chemicals, a guinea pig maximization test with the above 5 chemicals was performed. In each group, 6 animals were induced with one of the chemicals at 0.1% concentration by intradermal injection and at 1.0% by topical application. The animals were challenged with all 5 chemicals in concentrations of dilution by 10 from 0.1% to 0.001%. Under the conditions of 0.1% challenges, similar sensitization potencies were observed in PPD (6/6), PTD (6/6), PAP (5/6) and PAB (6/6) groups, but no positive reactions were elicited in the Sudan III group. The cross‐reactivities to PPD were confirmed in the animals challenged with PTD (6/6), PAP (6/6), PAB (6/6) and Sudan III (3/6). In the PTD‐induced group, positive responses to cross‐challenges were elicited by PPD (5/6), PAP (3/6), PAB (5/6) and Sudan III (1/6). The cross‐reactivities to PAP were observed only with PPD (2/5) and PAB (5/5). PAB‐induced animals responded only to PPD (1/6). The results indicate that all these chemicals except Sudan III are strong sensitizers. Their cross‐reactivities are different in sensitized conditions, respectively. The cross‐reactivities to PPD were higher than those to PTD, PAP and PAB.