Cytotoxic Effect of 5, 7-DHT on the Endogenous Glial Cells in the Dorsal Raphe Nucleus of the Rat / 대한해부학회지

This study was designed to clarify the cytotoxic effects of 5, 7-dihydroxytryptamine (5, 7-DHT) on the serotonergic neurons in the dorsal raphe nucleus, and to investigate the glial reaction during the neurodegenerative changes by light and electron microscopy. Adult male rats (Sprague-Dawley strain) weighing from 250 g to 350 g each were used as experimental animal. 5, 7-DHT (200 mg dissolved in 0.9% NaCl) was injected into the lateral ventricle of the rat brain with the Hamiton syringe fixed on stereotaxic apparatus. The control rats were given with the similar volume of 0.9% NaCl. The rats were sacrified on the 1st, 3rd, 5th, 10th and 20th day after the injection of 5, 7-DHT. The results were as follows : Glial reactions induced by 5, 7-DHT were also observed in DRN. In early experimental stage, microglial reactions prevailed, whereas astroglial reactions were prevailing in later stage. In addition, microglial cells phagocytosed and removed the degenerated cells. However, astrocytes in DRN did not show phagocytotic activities such as microglial cells. Based on the results, author thought that 5, 7-DHT act as a specific neurotoxin to serotonergic neurons in DRN, and induces severe neurodegenerative changes. The glial reactions in DRN are activated during the neurodegerative changes, and show characteristic patterns of glial reactions.

Cytotoxic Effect of 5, 7-DHT on the Serotonergic Neurons in the Dorsal Raphe Nucleus of the Rat / 대한해부학회지

This study was designed to clarify the cytotoxic effects of 5, 7-dihydroxytryptamine (5, 7-DHT) on the serotonergic neurons in the dorsal raphe nucleus, and to investigate the glial reaction during the neurodegenerative changes by light and electron microscopy. Adult male rats (Sprague-Dawley strain) weighing from 250 g to 350 g each were used as experimental animal. 5, 7-DHT (200 microgram dissolved in 0.9% NaCl) was injected into the lateral ventricle of the rat brain with the Hamiton syringe fixed on stereotaxic apparatus. The control rats were given with the similar volume of 0.9% NaCl. The rats were sacrified on the 1st, 3rd, 5th, 10th and 20th day after the injection of 5, 7-DHT. The results were as follows : The cytotoxicity of 5, 7-DHT resulted in severe neurodegenerations of the serotonergic neurons. Most degenerated cells mainly showed necrotic findings, but a few of them exhibited apoptotic features. That is, in early stage of this experiment, the degenerated cells showed edematic changes of cytoplasm, but their nuclei were relatively seen intact. In late stage, the cells showed dark degenerative changes both in their cytoplasm and nuclei. Thereafter the cells were autolysed or phagocytosed by neighboring glial cells. Based on the results, author thought that 5, 7-DHT act as a specific neurotoxin to serotonergic neurons in DRN, and induces severe neurodegenerative changes. The glial reactions in DRN are activated during the neurodegerative changes, and show characteristic patterns of glial reactions.

A Study on the Lead Exposure of Workers in Secondary Smelting and Litharge Making Industries / 대한산업의학회지

Two hundred and six male lead workers (86 lead workers from secondary smelting industries and 120 lead workers from litharge making industries) and 212 office workers who were not exposed to lead occupationally were studied to investigate the effect of lead on the health of lead workers in high risk operation to lead. Blood lead (PbB), zinc protoporphyrin in whole blood (ZPP), delta-aminolevulinic acid in urine (ALAU), Hematocrit (Hct) and hemoglobin (Hb) were selected as an index of lead exposure. Questionnaires of 15 lead related symptoms were provided to all study subject and filled up by themselves and reconfirmed the symptom answers by interviewing medical doctor. While the mean value of PbB, ZPP and ALAU of lead workers in secondary smelting industries were 62.7+/-14.6 microgram/dl, 103.1+/-60.5 microgram/dl and 7.4+/-10.3 mg/liter, those of lead workers in litharge making industries were 58.8+/-14.1 microgram/dl, 74.2+/-45.2 microgram/dl and 5.3+/- 7.9 mg/liter respectively, and there were statistically significant difference of mean values between two groups. Simple linear regression analysis of PBB on ZPP and ALAU shoved the steeper slope in secondary smelting industries than litharge making industries. Higher symptom prevalence rates of lead exposed group were observed in lead colic related symptom (S4) and neuromuscular symptoms compared with non-exposed workers. The prevalence of neuromuscular symptoms only showed dose-response relationship by the increase of PBB and ZPP. But more statistical significances were observed in neuromuscular symptoms by the increase of PBB than ZPP. On stepwise multiple regression using total symptom score as a dependent variable and PBB, ZPP, ALAU, Hct, Hb, age and work duration as a independent variables only ZPP and age contributed to the lead related symptoms.