Showing papers by "Seoul National University published in 1974"

Thymus-Dependent Lymphocytes of Peripheral Blood in Leprosy Patients

Abstract: Study of the numbers of thymus-derived lymphocytes by the rosette assay (T-RFC) in patients with leprosy reveals that lower than normal numbers of T-RFC are regularly seen in those patients with the active lepromatous form of this disease. Essentially normal numbers of T-RFC were found in inactive lepromatous, borderline, and indeterminate types of leprosy. The lowest percentages and lowest absolute numbers of T-RFC were encountered in patients with lepromatous leprosy resistant to chemotherapy. Patients with lepromatous leprosy complicated by erythema nodosum leprosum show numbers of T-RFC that are more nearly normal than the numbers of T-RFC in patients with uncomplicated lepromatous leprosy. These findings are discussed with respect to the pathogenesis of lepromatous leprosy and the T-RFC deficiency demonstrated in this disease. The possibility that transient defects in T-RFC numbers or function may predispose to lepromatous leprosy is proposed.

[Epizootiological study of theileriasis in Korea: Prevalence of the bovine theileriasis in relation to its vector, Haemaphysalis (Kaiseriana) longicornis Neumann. 1901]

Abstract: Investigations of some problems related to the bovine theileriasis and its vector have been undertaken in Korea. Owing to the nation-wide investment of dairy farming, hundreds of milk cattle were imported from foreign countries during the last l0 years. This caused some problems for the imported dairy cattle in terms of cattle piroplasmosis, from which native Korean cattle are immune. The bovine theileriasis has been studied from the beginning of the 20th centry in Korea, and the carriers and incidences of theilerial infection were reported by several authors during the past 60 years. Theilerial species in Korea is still unknown, but Han(1968) reported that it might be the same species as found in Japan. The latest work of Ishihara(1969) suggested that the species of the genus Theileria in Japanese cattle would be one similar to Theileria sergenti in Russian cattle. The tick responsible for the transmission of Korean theileriasis, Haemaphysalis (Kaiseriana) longicornis Neumann 1901 was incriminated as in the name of Haemaphysalis bispinosa (synonym) by Han(1968). The tick vector was re-examined thoroughly following the description of Hoogstraal et a1. (1969). There were no significant differences in the morphological character of ticks between Hoogstraal et al. and Jang(l973). The population fluctuation of H. longicornis in comparison with Boophilus microplus which is major important cattle tick was surveyed based on the collection of them at Suweon Stock Market through a year. The activities of the ticks begin on the central part of Korea in April and showed two highest population densities in May and July, and disappeared almost all in September.

Evaluation of mass treatment of malayan filariasis by diethylcarbamazine in Cheju Island.

Abstract: Control programme of malayan filariasis by diethylcarbamazine was set up in village, Cheju-Island, Korea. The daily dose of 6 mg per kg of body weight for 6 days was chosen as a chemotherapeutic course only for microfilaria positives, which was repeated with an interval of one or two months. For the evaluation of drug control programme the yearly posttreatment blood survey was carried out. The results collected from 1970 to 1973 were analysed from the various points of view, such as microfilaria positive rates, incidence as well as prevalence rates. The change of microfilaria counts was also utilized for the comparison of the intensity of infection among population in the four year blood surveys. Considering the extremely skewed distribution of average microfilaria density, the mode of frequency distribution of microfilaria density in a population was particularly taken into account for the evaluation of changing endemicity affected by diethyecarbamazine treatment. The equation; Y = a + b log X(a, b; constants, X=microfilaria density; Y=probit scale of cumulative frequency of positives to X microfilariae) was found to fit farily well the data collected from four-year surveys before and after treatment. From these data obtained, four regression lines have been drawn by determining "a" and "b"; two paramenters, which were increased year by year since inauguration of control programme. In the present investigation, it was verified that the chmotherapeutic control measure of malayan filariasis applied in a village of Cheju-Island has been successfully carried out and the quantitative level of endemicity inthis area has also been distinctly lowered within the four-year control programme.

Some theoretical aspects of hydrostatic extrusion and allied processes

Abstract: A lthough the mechanical principles of various extrusion processes are well understood in outline, very little is known about the stresses in the billet and product outside the working zone. Yet this is crucial to the optimal use of fluid pressure in hydrostatic forming. As a preliminary to a thorough investigation, some perspective is provided here by delimiting the range of pressure under which abnormal modes of flow occur. These are modes in which the billet either bulges or thins ahead of the die, or the product swells behind it. The analysis is based on standard slip-line theory and on overloading criteria at the stress singularities at entry and exit. Data are also presented on the distribution of stress along the boundaries of the working zone under arbitrary loading systems.

On the Heaving Motion of a Circular Disk in Shallow Water

Abstract: The hydrodynamic forces on a circular disk as a shallow draft ship for the forced heaving oscillation in shallow water are investigated. The boundary value problem is formulated by the use of the concept of the surface distributed sources so that integral equations for the source densities are obtained. In the case of long waves, the problem is solved analitically. The numerical solution of the integral equations is found and the added mass and damping factor are calculated. The exciting forces on a fixed circular disk in an incident wave are calculated according to Haskind-Newman's relation. The influence of the shallow water effect on the forces is illustrated graphically and discussed.

Values of intradermal test and multiple sputum examinations for Diagnosis of paragonimiasis

Abstract: This study was conducted on 4,003 inhabitants of six villages, Southern County of Che Ju lsland from April 18 to July 30, 1974 with purpose of studying. Relationship between intradermal reaction and egg detection rate, Egg detection rate by the number of sputum examination on the same subject, Comparison of direct sputum examination method (Whole volume of sputum in vinyl bag pressed between petri dishes) with concentration (2% NaOH) method, Estimation of sensitivity and specificity of the intradermal test in screening paragonimiasis. The results obtained are as follows: 1. Overall positive skin reaction rate was 57.7 % and egg positive rate regardless of skin reaction was 17.1 % the population studied. 2. Egg positive rate for negative skin reactors(wheal size smaller than 70mm(2)) was l0.l %, and that of positive reactors was 22.8 %. 3. Positive skin reaction rate increased as age increased, egg positive rate, however, revealed rather inconsistent distribution by age. 4. The egg positive rate showed a tendency of increase by increase of wheal size, though not so remarkably. 5. 2.9 % of egg positives by direct sputum examination method was negative when re-examined by concentration method; 2.6 % of egg negative sputum by direct method was egg positive by concentration method. It was found that the sputa showing discrepant result by two different methods had only a few eggs in whole sputum collected. 6. Egg positive rate by single sputum examination was 8.l %, by two examinations 14.6 % by three 19.2 %, by four 24.5 %, and by five examinations on the same individual was 20.5 %. 7. The estimated sensitivity and specificity of the skin test were 76.5 % and 42.7 % respectively under the postulation that all infected persons could be detected by four sputum examinations.

The periodicity of the microfilariae of Brugia malayi in Cheju Island, Korea.

Abstract: The periodicity of the microfilariae of Brugia malayi was studied in 9 human carriers from Shin-san Ri, Seong-san Myon, Cheju Island. The periodicity pattern was markedly nocturnal and the peaks were observed between 21:30 p.m. and 5:30 a.m. The average peak count was 1:30 a.m. and the percentage of peak count at this time was 95.3. The ratio of minimum of the average peak count percentage to the maximum was 8.3. The periodicity pattern of B.malayi in Cheju Island was compared with that in Inland and no differences were found between two forms. From the above observations, it was concluded that the periodicity of B. malayi in Korea is markedly nocturnal and closely resembles that in the strain of Penang, Malaya.

Effect of Near-Ultraviolet Irradiation on Sporulation by Pyricularia oryzae Cavara on Cultural Media

Abstract: Effects of near-ultraviolet irradiation on the sporulation of Pyricularia oryzae Cavara were investigated by daily count of conidial formation of the fungus grown at 27±1C on potato sucrose agar inoculated uniformly flooded with fungal suspension. Continuous irradiation with near-UV (366nm) on 4 isolates of P. oryzae generally shortened the time required to reach maximum sporulation, but the effect of continuous irradiation on the amounts of sporulation varied among isolates. Irradiation for the first 3 days resulted the highest sporulation and accelerated conidiophore formation. Sporulation, however, was less in continuous darkness or in darkness for the first 3 days. Near-UV absorbing, water-soluble and heat-unstable substances with maximum absorption at 325nm were detected from the cultures of an isolate irradiated for 4 days, but not from unexposed cultures. When the irradiated fungal extracts were added to medium, sporulation under irradiation increased remarkably. In darkness, both fresh and autoclaved fungal extracts depressed sporulation.

[A Follow-Up Study To Evaluate The Efficacy Of Mass Chemotherapy For Control Of Paragonimiasis]

Abstract: In the survey of l1,005 subjects in l3 villages of Che Ju lsland, 1,450 persons were egg-positive by repeated sputum examinations. The response rate to intradermal test ranged 50-80% of the population and to sputum examination for skin positive 60-70% in the first survey done in l964. 93% of all egg-positive was treated with 40 mg/kg body weight of bithionol on alternate days for 10-15 doses in l965. Follow-up studies were carried out in one year, three-year, five-year, and eight year after the mass treatment. The one year follow-up study covered 86.5% of all treated cases in all villages but only a part of the population of a few villages in further follow-up studies. In this paper only the result obtained from the age group of 7-18 years, the common population studied in every follow-up for the purpose of comparison, is presented. Intermediate hosts of P. westermani were examined at the same time. In one year follow-up it was found that 91% of egg-positive treated became negative. Three parameters, skin reaction, sputum examination, and infection status of intermediate hosts by area and year were used for comparison. Skin positive rate showed gradual decrease with more marked drop in Kang Chung where more thorough survey and mass treatment (about 43% of all infected persons estimated among whole population) were carried out than other areas (only 20-30%). The proportion of intermediate skin reation (60-100 mm(3) wheal size) increased markedly indicating decreased dose of infection which corresponds to the dropped infection rate and average number of metacercaria in crabs. Egg-positive rate in sputum examination done for skin positive reactors also presented similar pattern to skin reaction although it should be taken account that the result of 1964 was from repeated sputum examinations but that of other years from a single examination. Increased proportion of intermediate skin reaction which has much lower egg-positive rate probably played major role in decreased egg-positive rate. The infection rate of snail started to drop about one year earlier than crab; crab infection rate and intensity started to drop about four year after the mass treatment. The duration needed to show the change of infection status in intermediate hosts after the mass chemotherapy may correspond to the duration of survival of the parasite in the intermediate hosts. With the data available presently, it is difficult to determine on what point of the curve the present status is situated (on decreasing phase or increasing phase?), how far the rate will go down if it is on decreasing phase, and how long would it take in returning to the original status without further management. The result of follow-up study, however, strongly indicate that continous and intense chemotherapy may be able to put the paragonimiasis under control. Further follow-up study on total population including survey on changes of environment and eating habits is planned.

Clinical Trial of Tinidazole (Fasigyn) in Acute and Chronic Intestinal Amoebiasis

Abstract: Tinidazole (Fasigyn), a new drug which is active in vitro and in vivo against Entamoeba histolytica, was used in 30 Korean patients with acute and chronic intestinal amoebiasis. In aute amoebic dysentry eight of ten patients given tinidazole 150 mg q.i.d. for 10 days were cured clinically and parasitologically. In chronic intestinal amoebiasis, the parasitological cure was obtained 6 out of 10 patients given150 mg q.i.d. for 10 days and 8 out of 10 in patients given 300 mg q.i.d. for 7 days. Tinidazole is well tolerated and is free from serious toxicity. There was no significant alteration in blood count, liver function tests and urine analysis of any of the patients treated with tinidazole.