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Biomedical subjects

Soon Hyung Lee

Publications and source records attributed to Soon Hyung Lee.

At least 19 recordsLinked to original sources
PubMed1988

Clinical and histopathological findings in mice heavily infected with Fibricola seoulensis.

To observe the clinical course and intestinal histopathology in heavy infection of Fibricola seoulensis, an experimental study was performed in mice. Clinical, hematological and histopathological observation was done on 1, 3, 7 and 12 days after experimental infection with l,000 metacercariae. On the 11th day after infection, the mice began to die and all of the infected mice were dead by the 16th day. The infected mice showed gradual weight loss. Occult blood was detected after the 10th day. Diarrhea occurred after the 9th day and was recognized in all of the infected mice on the 12th day. Hemoglobin and mean corpuscular hemoglobin decreased significantly after the 12th day, and mean corpuscular hemoglobin concentration decreased in all infected mice. The histopathological changes were more marked in the duodenum than in the jejunum or ileum. Major changes were villous atrophy and crypt hyperplasia, with decreased villus/crypt ratio, inflammatory cell infiltration and stromal edema. The present results suggest that the cause of death of mice heavily infected with F. seoulensis should be malnutrition and severe fluid loss due to malabsorption, together with intestinal bleeding.

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PubMed1988

A human case of Centrocestus armatus infection in Korea.

A human case of Centrocestus armatus (Heterophyidae) infection was proved by identifying an adult worm collected after treatment with praziquantel in Korea. The case is 42-year old man who resides in a rural area in Sanchung-gun, Kyeongsangnam-do. The case was concomitantly infected with Clonorchis sinensis and had the history of eating raw freshwater fishes including Zacco platypus, which are known to be the second intermediate host of C. armatus in Korea. This is the first report of natural human infection by C. armatus in the literature.

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PubMed1988

Egg laying capacity of Fibricola seoulensis in mice and rats.

The egg laying capacity of Fibricola seoulensis was observed in mice and rats. In mice, the mean number of eggs produced by an adult worm a day was 116 at the first week after infection, 123 at the 2nd week and 42 at the 3rd week. Thereafter, the capacity of about 20 eggs/worm/day was maintained up to one year period. In rats, it generally produced more eggs; 49 at 1 week, 250 at 2 weeks, 216 at 4 weeks, 327 at 6 months and 11 at one year after infection. It survived longer than a year in mice and rats.

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PubMed1988

Stictodora sp. (Trematoda: Heterophyidae) recovered from a man in Korea.

Two adult specimens of heterophyid fluke, which belong to the genus Stictodora, were collected from the stool of a 24-year old man after chemotherapy. The flukes were morphologically characterized by their small body size (0.90~0.98 mm long and 0.38 mm wide) and peculiar structure of ventrogenital sac with armed gonotyl (with about 12~15 spines) not enveloping genital pore. Species identification is deferred until more worms are obtained, although they closely resemble Stictodora fuscatum (Onji and Nishio, 1916). The patient used to eat raw flesh of mullets and gobies, which are regarded as the infection source of Stictodora sp., together with 3 other kinds of heterophyids described elsewhere. This is the first record of human Stictodora infection in the literature.

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PubMed1988

The life cycle and larval development of Fibricola seoulensis (Trematoda: Diplostomatidae).

The life cycle of Fibricola seoulensis was studied in the laboratory and in the field, with special interests in the larval developments within the eggs and in the intermediate hosts. The first emergence of miracidia after incubation of eggs in 26C water began on the ninth day. The miracidia, elongate and cylindrical shape, had epidermal plates in the formula of 6, 9, 4 and 3, with two pairs of flame cells and lateral processes. A kind of fresh water snail, Hippeutis (H.) cantori, was found to shed furcocercous cercariae from the 13th day after experimental challenge with miracidia while Physa acuta failed to shed. The same kind of snail collected from the field also shed the same cercariae. The cercariae were equipped with 2 pairs of penetration glands and 5 pairs of flame cells. The tadpoles of Rana nigromaculata were found susceptible to experimental infection with the cercariae. The same kind of tadpoles collected from various areas were also found naturally infected. The metacercariae in the tadpoles which were infected experimentally became infective to the definitive host in 21 days. The metacercariae were located free in the body cavity of tadpoles, and attained sexual maturity in rats in 7 days. The present study successfully followed the complete life cycle of F. seoulenis and found that it is possible to maintain the life cycle in the laboratory.

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PubMed1988

Metacercariae of Echinostoma cinetorchis encysted in the fresh water snail, Hippeutis(Helicorbis) cantori, and their development in rats and mice.

The fresh water snail, Hippeutis(Helicorbis) cantori, caught from the rice paddies in Namyangju-gun, Gyeonggi-do, was found to be a new second intermediate host of E. cinetorchis in Korea. The metacercariae were found from 89(76.7 %) out of 116 snails examined and the average metacercarial burden was 4.7 per infected snails. Some developmental characteristics of E. cinetorchis were observed after experimental infection of the metacercariae to rats and mice.

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PubMed1988

[An epidemiological suryey of Echinostoma hortense infection in Chongsong-gun, Kyongbuk province]

An epidemiological study was performed to know the infection status of E. hortense among the human residents and fish intermediate hosts in Chongsong-gun, Kyongsangbuk-do. Out of 263 people examined, 59(22.4 per cent) were positive for the eggs of E. hortense. Total 152 fresh water tishes (9 species) were examined, and Odontobutis obscura interrupta, Misgurnus angullicaudatus and Squalidus coreanus were found to harbour the metacercariae of E. hortense. Juvenile or adult E. hortense were expelled from 35 out of 54 cases treated with praziquantel. The number of worms per individual ranged from l to 649, with the average burden of 51. The eosinophil count of infected persons ranged 1-24 per cent (6 per cent in average). The number of eggs per day per worm (EPDPW) in human host was estimated about 1,478. The results showed that Chongsong-gun is an endemic area of E. hortense.

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PubMed1987

In vitro effect of praziquantel on Paragonimus westermani by light and scanning electron microscopic observation.

The effect of praziquantel on P. westermani exposed in vitro was observed by stereomicroscope, light microscope and scanning electron microscope. Following results were found. The worms incubated in 0.01 micro-g/ml praziquantel were moving after 26-hour incubation. However, all of them were immobilized immediately after incubation in solutions over 0.1 micro-g/ml concentration. All of the exposed worms showed severe vacuolization not only in tegument but in subtegument, intestine, ovary, testis, Mehlis' gland and excretory bladder. Vacuoles in tegument burst out to form craters. As incubation time went on, tegumental structure was disintegrated severely. The worms exposed to praziquantel were observed to be immobilized and be vacuolized of all tissues. Disintegration of reproductive organs suggests that praziquantel have suppressive effect on egg production when the flukes are not killed. The drug effects were found more related with incubation time than with drug concentration.

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PubMed1987

Scanning electron microscopical findings of Echinochasmus japonicus tegument.

Tegumental ultrastructures of Echinochasmus japonicus were observed by scanning electron microscopy. The worms were recovered from albino rats which were experimentally infected with the metacercariae obtained from Pseudorasbora parva. Followings are summarized findings. The worms were minute and plumpy gourd-shaped with attenuated anterior and round posterior end. The tegument of whole body was wrinkled transversely and covered with cobblestone-like cytoplasmic processes. Head crown was armed with 24 collar spines which were embedded in cytoplasmic pockets. The spines were arranged in a row with an interruption at dorsomedian line, however, the 2nd and the 4th spines were outstretched more than others. Oral and ventral suckers were muscular with numerous type II sensory papillae, and genital pore opened between the two suckers. Tegumental spines were spade-shaped with broad base and pointed tip. They were compact in ventro-lateral tegument or dorsal surface of anterior body. The were not found between the two suckers and dorsal surface of posterior body. Two types of sensory papillae, uni-ciliated (Type I) and roundly swollen sensory papillae (Type II), were observed. The type I papillae were chiefly distributed on ventral surface of tegument and type II were on the lips of suckers. Arrangement of collar spines, shape and distribution of tegumental spines or sensory papillae are regarded as characteristic features of E. japonicus.

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PubMed1987

Histopathological changes of the liver after praziquantel treatment in Clonorchis sinensis infected rabbits.

The rabbits were infected with Clnorchis sinensis and were treated with praziquantel at the dose of 50 mg/kg x 2 x 2 days afer 1, 2, 4, 8 weeks and 7 months from the infection. Their livers were observed histopathologically 1, 4 and 12 weeks after treatment. The findings are summarized as below: The changes of the liver in control rabbits were relatively mild until 2 weeks after infection. However, widening and thickening of bile ducts, proliferation of biliary epithelium and periductal fibrosis were moderate after 4 weeks from infection and those changes were severe after 8 weeks and 7months. Goblet cell metaplasia was found after 8 weeks from infection. The mild changes of 2-week infection group were completely recovered by 4 weeks after the treatment. In the groups of 4 or more weeks after infection, the changes of bile ducts became milder in the degree after the treatment, but were still found 12 weeks after the treatment. As the infection duration was passed, more severe changes were observed after the treatment. In this context, it is concluded that the liver changes of acute clonorchiasis in the early two weeks are reversible by treatment while chronic biliary epithelial changes are irreversible. Therefore, early treatment should be recommended as possible to minimize the remaining histopathological changes of liver in clonorchiasis.

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PubMed1987

Histopathological and serological observations on experimental anisakiasis of rabbits.

This study was performed to observe histopathological changes and serological reactions in chronic anisakiasis of rabbits. Each rabbit was infected per os with 30 larvae of Anisakis type I. Their sera were collected chronologically and the rabbits were killed for histopathological examination, 3, 13, 20, 30, 60, 90 and 150 days after the infection. The results were summarized as below. Most of the larvae were recovered from the stomach, but a few from the omentum, intestine, mesentery and abdominal wall. The recovery rates and distribution of worms by organ were not differed by duration of infection. Histologically the lesion was abscess type on 13 days, i.e., the dead worms were surrounded by fibrinous exudate, histiocytes and thick zone of numerous inflammatory cells. After 30 days, histiocytes were found to invade the worms and the lesion was changing into abscess-granulomatous type. Also a calcified worm was found on the 30th day. After then the worms were observed to be dissolved slowly until 90 days. On 150 day, only one calcified worm was observed. The levels of serum IgG antibody by ELISA reached their maximum 30 days after the infection. After then, it decreased slowly until 150 days after the infection. Above serological and histopathological findings indicated that antigenic stimulation from degenerating Anisakis larvae was the greatest during the first 30 days after infection. This period was corresponding with the beginning of worm resolution or calcification. Serologic test by ELISA would be a valuable tool for confirming chronic anisakiasis.

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PubMed1986

Larval anisakids collected from the yellow corvina in Korea.

Larval anisakids found in the yellow corvina (Pseudosciaena manchurica), a marine fish caught in the Yellow Sea, were classified by their morphological types. Total 1,068 anisakid larvae were collected from 30 fish examined, with the average number per fish of 35.6. They were classified into Anisakis type I larvae of Berland (859 in number, 80.4%), Contracaecum type A of Koyama et al. (13, 1.2%), Contracaecum type C'(new type) (55, 5.1%), Contracaecum type D of Koyama et al.(18, 1.7%), Contracaecum type D'(new type) (77, 7.2%), Contracaecum type V of Yamaguti(3, 0.28%), Raphidascaris sp. of Koyama et al. (1, 0.09%) and unidentified (42, 3.9%). Contracaecum type C' and D' were considered new in the literature.

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PubMed1986

Growth and development of Pygidiopsis summa in rats and mice with a supplementary note on its morphological characters.

The growth and development of Pygidiopsis summa were studied in experimental rats and mice, and a special reference was given to its morphological characters differed from the type species, P. genata. The metacercariae were obtained from young mullets (Mugil sp.), and total 21 rats and mice infected each with 1,000 metacercariae. Worms of various ages of infection, from 3 to 28 days, were subjected to a microscopic observation. The worms grew rapidly and remarkably in size up to 10 days of infection, to become 0.53-0.82 mm long and 0.31-0.39 mm wide, but nearly stopped the growth thereafter. Their genital organs developed more rapidly and fully matured within 3-5 days. At 3 days several eggs were found in uterus. The presence of two groups of small spines, 5-6 on the right and 7-9 on the left side of the genital apparatus, was a new finding in this study and considered a distinct character of P. summa. The morphology of ventral sucker and intestinal ceca was also different from P. genata. This study confirms the validity of the species, P. summa.

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PubMed1986

[Tegumental ultrastructures of Echinostoma hortense observed by scanning electron microscopy]

The tegumental ultrastructures of Echinostoma hortense adults were observed by scanning electron microscopy. The worms of 4 weeks of age were harvested from albino rats experimentally infected with the metacercariae obtained from the loach. The results were as follows: The worms were leaf-like and their anterior end portion, including oral sucker and head crown, ventrally curved to face posteriorly. The tegument of whole body was wrinkled transversely and covered with cobblestone-like cytoplasmic processes. The oral sucker had roundly swollen (type II) sensory papillae on the ventral half of its lip and uni-ciliated knob-like (type I) sensory papillae, arranged in 2-3 rows, on the dorsal outer surface. Aspinous ventral sucker had many of type I papillae arranged in a circular band on its outer surface. The tegument around the genital opening was of similar feature to the ventral sucker, but sensory papillae were hardly found around the former. Scale-like spines with broad base and round tip were distributed densely on the tegument anterior to the ventral sucker but they became sparse in posterior half of the ventral surface, finally to disappear at posterior extremity. A few number of type I papillae were observed on the ventral surface. The results suggest that the tegument of E. hortense is similar to that of other echinostomes especially E. revolutum. But the number and arrangement of collar spines, and/or the type and distribution of sensory papillae seem characteristic features of E. hortense differed from other echinostomes.

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PubMed1986

Human infections by Heterophyes heterophyes and H. dispar imported from Saudi Arabia.

Two human cases of Heterophyes heterophyes and H. dispar infections were proven by the recovery of their adult worms. The cases were 38-year and 40-year old Korean workers who had been in Saudi Arabia for 4-6 years and returned home in 1983 or 1984 with gastrointestinal troubles. In Saudi Arabia they had eaten raw brackish water fishes such as the mullet. After the treatment with 10 mg/kg praziquantel and purgation with magnesium salt, a total of 19 specimens of H.heterophyes and 140 of H. dispar were collected. It is of interest that the worms persisted in a patient although he had been back in Korea for 14 months. This is the first report on imported heterophyiasis in Korea. Human infection by H. dispar is the first record in the literature.

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PubMed1986

Ten human cases of Fibricola seoulensis infection and mixed one with Stellantchasmus and Metagonimus.

Ten soldiers of the Korean Army were found to have F. seoulensis ova in their faeces. These men were treated with praziquantel and the worms passed after purging were successfully collected in one case: 59 F. seoulensis, 68 Metagonimus and 2 Stellantchasmus falcatus were collected. 2 men were also infected with Clonorchis sinensis. All the cases of fibricoliasis had eaten raw or undercooked snake meat or frogs during survival training. All were egg-negative 2-6 months after treatment.

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PubMed1986

Growth and development of Fibricola seoulensis metacercariae in tadpoles.

In order to observe the growth and development of Fibricola seoulensis metacercariae, the tadpoles of Rana nigromagulata were experimentally infected with the cercariae. The metacercariae of various developmental stages were recovered from the tadpoles after 2 to 65 days of infection. They were prepared for morphological observation, and were given orally to mice to observe their infectivity. The following results were obtained. All of the tadpoles exposed to the cercariae were observed to harbour the larvae in their abdominal cavity. The young metacercariae of 2 days after infection were 121.1 micrometer long and 63.3 micrometer wide. They grow linearly for the first 14 days to be 262.0 micrometer long and 166.4 micrometer wide. Thereafter, no more growth recognized until 65 days. The larvae of 2 days old were similar with cercarial body and had 2 suckers, a pharynx, two ceca and a primordium of germ cells but no tribocytic organ. On the 8th day, they had tribocytic organ, and their morphology resembled that of mature metacercariae. The metacercariae younger than 10 days could not infect the mice. Only the metacercariae older than 14 days had infectivity. The recovery rate increased by the age of metacercariae from 19.0% in 14 days old to 70.0% in 40 days old. Above findings indicate that the tadpole is indispensible for metacercarial development and it needs at least 2 weeks for maturation. The tadpole is a pivotal host in the life cycle of F. seoulensis for connection between the snail and the frog.

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