Showing papers by "Yonsei University published in 1983"

[Epidemiological Studies On Clonorchis Sinensis Infection Along The Nam-River In Gyeongnam Province, Korea]

Abstract: An epidemiological study on Clonorchis sinensis infection along the Nam-river (total length; 186km) flowing in Gyeongsang-nam-do, southern part of Korea, was carried out. Formalin-ether concentration technique and Stoll's egg counting method were employed to figure out the prevalence of C. sinensis infection. For the detection of cercariae from Parafossarulus sp., the snail host of C. sinensis, each snail was placed in aerated tap water, and examined for expelled cercariae. For observing the metacercariae the fresh water fish favorably eaten in raw conditions were prepared by means of pressing the muscles between tow slide glasses and/or by digesting them with artificial gastric juice. The fresh water fish were fed to the rabbits to get the worms and to identify the morphology of adult C. sinensis. The results are summarized as follows: 1. Overall prevalence of C. sinensis infection was 38.7% form 5,291 examinees; 44.1% (1,408 out of 3,196) in male and 30.4% (637 out of 2,095) in female. 2. The prevalence rates were 42.0% at the upper stream, 41.2% around the vicinity of Jinyang-lake, 34.2% at Jinju city, 34.2% at middle stream and 40.3% at down stream regions, respectively. 3. By age, the highest positive rate (53.4~54.3%) was observed in 30 to 59 years of age. In this age group, the rate in males was 59.7~62.2%, and in females 42.2~44.4%. In the age group of less than 19years it was 7.5~20.9%. 4. By social strata, the positive rate was 16.5% in the primary school children, 22.6% in school students, 46.2% in teachers and local officers and 49.6% in the general inhabitants. 5. The quantitative examinations with the stool collected from clonorchiasis cases revealed that the light infection (less than 4,000/EPG) was 53.6%, moderate infection (4,001~10,000/EPG) 30.3% and heavy infection (more than 10,001/EPG) 16.1, respectively. More than half of total cases examined were light infection, and 73.2% of female examinees were lightly infected with this fluke. 6. The average value of EPG was 4,963 (male, 6,057; female, 2,557 and the highest value was obtained from the age group of 30 to 59 years (5,240~6,454). 7. The prevalence of Metagonimus yokogawai infection in humans was 5.5%, and 89.8% of metagonimiasis cases were double-infected with C. sinensis. The highest prevalence rate was observed in JInju city(11.2%). 8. Total of 5,005 Parafossarulus sp., the snail intermediate host of C. sinensis, were examined for the detection of cercariae. The cercarial expulsion rate was 0.34%, and the snails collected in Jin-yang-lake side and in the down stream expelled mainly the cercariae of C. sinensis. 9. About 788 cercariae/day (range: 127~1,503) were expelled daily from a snail naturally infected with C. sinensis. The snails which released more than 1,000 cercariae/day were 30.8% out of total collected. A snail uniquely released 5,840 cercariae/day in this study. 10. The other trematode cercariae besides C. sinensis were also detected, and the rates out of total snails were the cercariae of Loxogenes liberum 6.71%, Cyathocotyle orientalis 0.26%, Notocotylus attenuatus 2.52% and Mucobucaris 0.54%. 11. Ten out of 18 species of fresh water fish caught along the river harbored the vetacercariae of C. sinensis. The highest rate of metacercarial infection in fish wa detected in Pseudorabora parva(85.9%). The fish mainly eaten by the inhabitants along the Nam-river, and the metacercarial infection rates were: Zacco platypus 8.0%, Hemibarbus sp. 18.2~26.7%, Gnathopogon sp. 37.5%, Ischikauia steenackeri 42.9% and Pseudogobio esocinus 16.7%. 12. Out of 36 P. parva, the number of metacercariae were about 109 (range; 18~446) per fish and 27 per gram of flesh. The fish caught in spring harbored the highest number of metacercariae. As indecated above, the prevalence of C. sinensis infection in the inhabitants resding around the Nam-river was relatively high. The farther toward the upper stream areas, the higher was the positive rate of C. sinensis infection, and most of clonorchiasis cases were lightly infected. The snail hosts of C. sinensis distributed all around the Nam-river. Several species of freshwater fish were infected with the metacercariae of C. sinensis and the infection rates were relatively high. To prevent C. sinensis infection in the endemic areas, the effective health education system is suggested as a control measure, althought mass treatment is also expected to be useful, using chemotherapeutic agents such as "praziquantel", a recently developed anthelminthic for C. sinensis infection.

An experimental study on corneocytes of acutely and chronically irritated skin

Abstract: An experimental study concerning the effect of acute and chronic irritation on corneocytes was made in relation to cell number, size, and shape. Corneocytes from skin acutely irritated with a rough towel differed from those of normal skin: There was about a 60% decrease in the count and the corneocytes were 14% smaller in size on day 1 of the experiment. These parameters became normal in count and size after 10 days and 5 days, respectively. Concerning the morphological classification of cell outlines, there was no significant difference between the experimental and control groups except for slightly increased numbers of irregular cells in the experimental group. For the chronic irritation study, subjects were scrub nurses who had worked in the operating room for more than 3 years; ward nurses were used as a control group. Corneocytes from scrub nurses differed from those of the nonirritated skin of ward nurses; the number was twice as high on day 1 of the experiment. Two and four days later, the cell number markedly decreased and was similar to that in the control group. Throughout the experimental period, the surface of the corneocytes was 15% smaller in the experimental group than in the control group. There was no significant difference between the two groups with regard to corneocyte morphology.

Evaluation Of Specific Ige Antibody In Clonorchis Sinensis Infection.

Abstract: Serum IgE level and Clonorchis specific IgE in individuals with Clonorchis sinensis were determined by radioimmunosorbent(RIST) and radioallergosorbent technique(RAST) respectively. Highly significant elevations of serum IgE (P<0.001) and specific IgE antibodies (P<0.01) were observed in area from individuals with clonorchiasis. The mean values of serum IgE in individuals with clonorchiasis and healthy individuals were 2,372 IU/ml and 364 IU/ml respectively and specific IgE antibodies of both groups were 52.0 and 4.4%. A close correlation(r=0.9451) between serum IgE level and specific IgE antibodies were observed and correlation (r=0.6056) between serum IgE and EPG and between specific IgE and EPG(r=0.5693) were also observed.

Changes In The Pathogenicity Of Naegleria Fowleri By Several Brain Passage In Mice

Abstract: The pathogenicity of free-living amoeba, Naegleria fowleri, is influenced according to the strain, cultural condition and host (Culbertson et al., 1968; Carter, 1970; Wong et al., 1975). Phillips (1973) demonstrated that Entamoeba histolytica became avirulent after more than 2 year maintenance in axenic culture in vitro. This study was carried out to compare the difference in pathogenicity between two strains of N. fowleri, one of a prolonged maintenance in axenic medium and the other one obtained by serial brain passage in mice. The 0 strain was that N. fowleri had cultivated axenically more than 7 years in CGVS medium. The 2-1 strain was obtained from the brain of mouse inoculated intranasally with a strain, which was from the mouse brain infected with 0 strain, and cultured for 15 weeks until the beginning of this experiment. White male mice weighing 18-22 g were used. Mice were anesthetized by an intraperitoneal injection of about 1 mg secobarbital, and inoculated intranasally with 10 x 10(4) live N. fowleri trophozoites in a 5 microliter cell suspension. Sluggish behaviour, nervousness, rotation and leg paralysis were developed earlier and more frequently in the 2-1 experimental group than the control 0 group. Pathological changes such as inflammatory and necrotic lesion were observed in the olfactory and anterior portion of brain, and these changes were more extensive in the 2-1 group. The edematous and inflammatory changes in lung were demonstrated in mice died after 13th day post-inoculation. The experimental mice of 2-1 group began to die suddenly from 7th day post-inoculation, and the survival time in 2-1 group mice was shorter than 0 group mice. The typical primary amoebic meningoencephalitis was developed in the mice inoculated intranasally with N. fowleri. The prolonged maintenance of N. fowleri amoebae in axenic CGVS medium was observed to have lost their original pathogenicity for mice, but their pathogenicity was restored by serial brain passage in mice.

Critical loading conditions and stress intensity factors for partial or entire closure of a Griffith crack under thermo-mechanical loading

Abstract: Two-dimensional stresses and displacements around a general elliptic cavity imbedded in a infinite elastic body are derived in terms of thermo-mechanical loads by using the Muskhelishvili's complex variable approach and the modified McClintock and Walsh's crack/cavity closure model. The mechanisms of line crack-closure are proposed. The critical loading conditions and stress intensity factors for the case of a partial or entire crack-closure are determined analytically on the basis of McClintock and Walsh's crack-closure assumptions.

[Distribution Of Medically Important Freshwater Snails And Larval Trematodes From Parafossarulus Manchouricus And Semisulcospira Libertina Around The Jinyang Lake In Kyongsang-Nam-Do, Korea]

Abstract: The Jinyang Lake is dammed up Nam River, and surrounded by Jinju city and four counties; Jinyang, Sanchong, Hadong, and Sachon in Kyongsang-Nam-Do, Korea. The area around this man-made lake have been known as an endemic focus of clonorchiasis in Korea. The present study was first aimed to know the distribution of freshwater mollusks including medically important snails, and larval trematodes shed from Parafossarulus manchouricus and Semisulcospira libertina. In addtion to above studies, water analyses in each snail habitat were carried out in order to figure out a part of their environmental factors. This malaco-ecological survey was done at the six areas around upper, middle and lower parts of the lake for 4 months, August-November, 1983. Total nine species of freshwater mollusks were collected throughout the study: 4 species of gastropods; Semisulcospira libertina, Cipangopaludina chinensis, Parafossarulus manchouricus and Radix auricularia, and 5 species of bivalves; Unio douglasiae, Anodonta woodiana, Lamprotula gottschei, Corbicula fluminea and Limnoperma lucustris. Out of nine species of freshwater mollusks, three species of gastropods; S. libertina, P. manchouricus and R. auricularia were medically important in terms of the transmission of digenetic trematodes to humans. P. manchouricus and R. auricularia were mainly collected from the shallow ponds and the irrigation channels with the muddy basin, but S. libertina and the bivalves were only collected from the stream of Nam river where the gravels and rocks were dominant. The levels of dissolved oxygen(D.O.) and biochemical oxygen demand (B.O.D.(5)) of the water specimens sampled from the study areas ranged from 6.0 to 9.6 ppm and from 0.4 to 1.6 ppm respectively. As a result, it is considered that water system around the Jinyang Lake might be relatively clean without any heavy pollution of aquatic microorganisms and organic materials during the period of this study. On the other hand, eight metalic constituents from the water samples were also assayed, and all metalic ions detected were remarkably low below the legal criteria. However, calcium ion in the water samples from the habitats of P. manchouricus was considerably higher than others. Infection rates of digenetic trematodes in the snails were 6.9 % in P. manchouricus and 4.8 poercent in S. libertina, respectively. P. manchouricus snails harboring with the cercariae of Clonorchis sinensis were only 0.14 % among the snails examined and other trematode cercariae except cercaria of C. sinensis were; furcocercus cercariae, cercaria of Loxogenes liberum type I and II. S. libertina snails parasitized with the cercariae of Metagonimus yokogawai were 1.5 % out of the snails examined and no cercaria of Paragonimus westermani was found in S. libertina snails in the present study. Digenetic trematode cercariae other then M. yokogawai in S. libertina snails were: Cercaria yoshidae (B type), Cercaria cristata, Cercaria innominatum, Cercaria of Centrocestus formosanus and Cercaria nipponensis.

Comparison Of Tia With ELISA For Circulating Antibody Detection In Clonorchiasis

Abstract: A comparison was made of a new serological method, thin layer immunoassay (TIA), and an established method, enzyme-linked immunosorbent assay (ELISA), in the detection and quantification of antibodies in clonorchiasis. Saline extract of lyophilized Clonorchis sinensis adult worm was used as antigen, and TIA by the method of Elwing et al. (1976) and ELISA by Voller et al. (1974) were performed. Using sera from known clonorchiasis cases, 100 % of the sera tested were positive by TIA and 88.3 % by ELISA. TIA produced false positive results in 14 out of 36 cases, which were 10 amoebiasis cases, 16 paragonimiasis cases and 10 healthy controls. ELISA, however, produced a small number of false positives, 7 out of 55 cases. There was correlation between immunoglobulin G level in sera and ELISA value (correlation coefficient, 0.69), whereas no correlation between immunoglobulin G level and TIA result. The performance of TIA and ELISA was not correlated in the results using homologous antigen.

Grass Roots Democracy: The Case of the Korean Labor Movement

Abstract: This is a sample study of two chapters of the Korean Automobile and Transport Workers' Union (KATWU), located in the capitol city of Seoul, Korea. The purpose of this study was to ascertain whether the membership of the union had lost their zest for democratic governance within the union organization in light of the government's restrictive control of union activities and the bureaucratization of the organization. Results of the survey reveal that the rank and file of KATWU have been effectively using the procedural guarantees imposed by the government even in the absence of a formalized party system. The rank and file have been active in the election process and by their participation in the internal government of the union, have established control of the leadership structure. Without a true adversarial relationship with management and with the intrusion of government in the affairs of labor and management, it is questionable whether labor leaders can fully exercise the power of force they have behind them. In this sense, accountability is difficult to test. Nevertheless, it is apparent that the rank and file have established a pattern of leadership accountability by retaining control of the leadership structure.

Long term effects of IUD on the human endometrium. Histologic, histochemical and ultrastructural studies.

Abstract: To evaluate the longterm effects of a IUD on the human endometrium and find the possible contraceptive mechanism of the IUD histologic histochemical and ultrastructural studies of human endometrial biopsies from 44 normal contorls and 178 IUD wearers were made. Histologic findings included interstitial hemorrhage inflammatory reaction hyperplasia atrohy focal necrosis and squamous metaplasia. However all of these findings were either infrequent or insignificant except for inflammatory reaction. Histochemical enzymatic and ultrastructural findings were also unremarkable. The most significant finding was asynchronism between cyclic dating and endometrial histologic dating showing delayed endometrial maturation in the majority of IUD users. In summary IUD insertion results in mild histologic-alteration in the human endometrium but the inflammatory reaction and asynchronous endometrial maturation may play some role in the antifertility action of an IUD. (authors modified)

Light Curves and Ca II Emissions of V711 Tauri during 1981–82

Abstract: The light variation of V711 Tauri was first discovered by Cousins, who suspected the variation with an amplitude of ΔV = 0m.11. This light variation was confirmed by Landis and Hall (1976). This star has been identified as the brightest RS CVn-type star by Bopp and Fekel (1976). Bopp et al. (1977), using Cousins’ old data and their data made nearly 13 years later than those of Cousins, found that the observations show the same light curve shape and amplitude and the minimum light falls very nearly at 0P.0 computed with their ephemeris.