Toxoplasma gondii antibody titers in sera of children admitted to the Seoul National University Children's Hospital

A total of 542 children under 10 years of age, admitted to the Seoul National University Children's Hospital, was examined for antibody titers of Toxoplasma gondii using indirect latex agglutination (ILA) test. Among them, 7.7% showed positive titers higher than 1:32, without significant difference between males (7.3%) and females (8.5%). The seropositive rate increased with age although the statistical significance was negligible (0.05 < P < 0.1). By residential areas, the prevalence appeared higher among children from southern provinces (Kyongsang-do and Cholla do) than those from other areas, but the statistical significance was also very low (0.05 < P < 0.1). When the seropositive cases were analyzed by coincidental diseases, the prevalence was significantly higher in patients with congenital diseases than in patients with non-congenital diseases (P < 0.05). The results showed that the seropositive rate of toxoplasmosis in children examined was not high compared with other endemic countries. Some correlations are suggested between toxoplasmosis and congenital anomalies in Korea.

Effects of gamma-irradiation on intracellular proliferation of Toxoplasma gondii RH tachyzoites

A quantitative assay was performed on the effects of gamma-irradiation (30-300 Gy) on intracellular proliferation of Toxoplasma gondii RH tachyzoites in human leukemic HL-60 cells and murine peritoneal macrophages by means of 3H-uracil uptake assay. Infected non- irradiation group (NI) and uninfected group (incubating only host cells) were prepared. The 3H-uracil uptake by tachyzoites of NI group 12-24 hrs after infection was 2,190-4,787 counts per minute for macrophages and 2,967-8,254 for HL-60 cells, whereas the irradiated tachyzoites revealed only 381-703 (100 Gy) and 218-408 (300 Gy) for macrophages, and 1,911-2,618 (30 Gy), 1,253-1,384 (70 Gy), 1,013-1,090 (100 Gy), and 483-588 (300 Gy) for HL-60 cells. The proliferation inhibition rate was similar in macrophages and HL-60 cells, for example, 89-94% and 80-94% respectively by 300 Gy, 12-24 hrs after infection. It is concluded that RH tachyzoites of T. gondii are severely affected by gamma-irradiation in their capability of intracellular proliferation.

Two rare cases of Diphyllobothrium latum parvum type infection in Korea

Two rare cases of human infection with parvum (dwarf) type of Diphyllobothrium latum [syn. D parvum (Stephens,1908)], were discovered in Korea. The first case was a 46-year old houseife, from whom a kind of pseudophyllidean tapeworm eggs was detected in the feces. She was treated with praziquantel and purged, and a complete strobila with scolex, 120 cm in total length, was recovered. She recalled that she had eaten raw trouts at a raw-fish restaurant near the Chungju Lake. Another patient was a 22-year old medical student (male), who used to eat raw sea-foods. He discovered a chain of tapeworm proglottids, 15 cm in length, discharged spontaneously in his stool and brought it for identification. The worms from the two cases were compatible with D. parvum (Stephens, 1908) of which the taxonomic significance has long been questioned. After a detailed morphological study and review of literature, we designated the worms as D. latum parvum type. This is the first report on the occurrence of this rare type of D. latum infection in Korea.

Karyotypes of Pneumocystis carinii from Korean rats

Molecular karyotyping was applied to Pneumocystis carinii(Pc) from two strains of experimental rats, Sprague Dawley(SD) and Fisher(F), in Korea. Field inversion gel electrophoresis and contour clamped homogeneous electric field electrophoresis resolved 15 chromosomal bands from the Pc. The size of the bands was estimated 270kb to 684kb from SD rats, and 273kb to 713 kb from F rats. The bands of 283 kb from SD rats and of 273 kb from F rats stained more brightly suggesting duplicated bands. Total number of chromosomes was at least 16, and total genomic size was estimated 7 x 10(6) bp. All of the bands from F rats hybridized to the probe of repeated DNA sequences of Pc and the band of 448 kb size was proved to contain rDNA sequences, but Pc. chromosome bands from SD rats showed no reactions to the probes. The 2 different karyotypes of P. carinii from 2 strains of rats were maintained consistently for 2 years.