A Xenoreactive Complement Hemolytic Assay in Xenotransplantation / 대한진단검사의학회지

BACKGROUND: Xenotrasplantation is a possible alternative for organ shortage in clinical transplantation, but hyperacute xenograft rejection has been a big huddle. Pre-existing natural xenoreactive antibodies and consequent activation of the complement system are thought to play major roles in hyperacute rejection. To set a monitorig test for the hyperacute rejection in xenotransplantation, we optimised a complement hemolytic assay and evaluated its in-vitro precisions and clinical implications. METHODS: Complement hemolytic activities of normal human sera on rabbit or porcine red blood cells (RBCs) in each gelatin veronal buffer with or without dextrose were compared to retrieve optimal conditions for assay. The precision and activity range of normal human sera were evaluated at a given optimum condition. And we also assayed complement hemolytic activities of the sera obtained from various models of xenotransplantated animal, and assessed its association with other clinical parameters. RESULTS: The assay with rabbit RBCs in gelatin veronal buffer containing dextrose showed linear hemolytic reactions in the broadest range of serum dilutions with the least background hemolysis. Its intra- and inter-assay coefficient variation was 1.3% and 8.1%, respectively. The complement hemolytic activity was dependent on the serum levels of C3 and IgM. Severe hyperacute rejection in lung xenotransplantation was accompanied with a rapid decline of serum complement hemolytic activities compared to the basal level. CONCLUSIONS: The complement hemolytic assay using rabbit red cells has a clinically acceptable range of precision, and seems to be useful for the evaluation of hyperacute rejection in clinical xenotransplantation.

Present Status of Human Paragonimiasis and Intestinal Parasitic Infection in Bokildo (Islet), Korea / 감염

BACKGROUND: Bokildo (Islet) has been well known as an endemic area of paragonimiasis in Korea, and still crayfishes caught from this area are used as source of intermediate host of experimental paragonimiasis. For the reason, this study was carried out to elucidate the present status of human paragonimiasis in this region and intestinal parasitoses were studied at the same time. METHODS: From June 9 to June 12, 1999 authors visited Buyong-ri and Buwhang-ri which are located in the endemic area. All possible inhabitants including nursery children, primary and middle school children were examined by intra-dermal skin test with veronal buffered saline (VBS) antigen of Paragonimus westermani and Clonorchis sinensis. Sputa were collected from 22 adults of positive reactors. Stool examination was done for the intestinal parasites, and anal swabs with adhesive tape for the pinworm were carried out simultaneously. RESULTS: Overall positive rate in skin test was 9.5% in inhabitants, and higher rate was observed in older age groups. On microscopic examination of sputa for pargonimiasis, 2 egg-positive cases from 55-year old man and woman were detected. Prevalence rate of intestinal parasites was 7.8% (26/332) and the most predominant infected parasite was Trichuris trichiura (4.2%). The pinworm infection rate was 29.7% (nursery school children 30.0%, primary school children 29.6%, respectively). CONCLUSION: Through this study human paragonimiasis was confirmed and the life cycle of Paragonimus westermani was known to be maintained continuously in this region. Meanwhile control of intestinal parasites should be performed, especially in school children.

Neurobehavioural study of subchronic administration of oxydemeton-methyl (insecticide and acaricide) in rats.

Oxydemeton-methyl, an organophosphate insecticide and acaricide produced decrease in the exploratory behaviour and prolongation of barbitone sodium induced hypnosis in rats after intermittent aerosol spray inhalational exposure, for 1/2 hour daily for 7 consecutive days, compared to the saline control group. Further, ED50 +/- SEM value for haloperidol induced catalepsy, CD50 +/- SEM value for pentylenetetrazole induced seizure and CI50 +/- SEM value for electroshock (i.e. the dose of haloperidol, PTZ and intensity of electroshock producing catalepsy or positive seizure response in 50% of rats) were significantly decreased after 7 days exposure to oxydemeton-methyl compared to that of saline control group. The study has established the central nervous system depressant effect, extrapyramidal effect and proconvulsant potential of oxydemeton-methyl which is widely used by the agricultural workers in the form of field spray.

An observational study on neurobehavioural effects of acute oxydemeton-methyl (insecticide and acaricide) exposure in rats.

Oxydemeton-methyl, an organophosphate insecticide and acaricide produced decrease in the exploratory behaviour and prolongation of barbitone sodium-induced hypnosis after intermittent aerosol spray inhalational exposure for 1 h in rats compared to the saline control group. Further, CD50 +/- S.E.M. value for pentylenetetrazole (PTZ) and CI50 +/- S.E.M. value for electroshock (i.e. the dose of PTZ and intensity of electroshock producing positive seizure response in 50% of rats) were significantly decreased by acute exposure to oxydemeton-methyl compared to that of saline control group. The study has established the central nervous system depressant effect and proconvulsant potential of oxydemeton-methyl which is widely used by the agricultural workers in the form of field spray.

Central nervous system pharmacology of propranolol.

In rats, propranolol potentiated alcohol and pentobarbitone hypnosis, but not barbital sleeping time, indicating enzyme inhibition as a possible mechanism of potentiation. Propranolol showed anticonvulsant effect on normal and reserpine treated rats by MES test, but showed dose related lowering of MET. Probable mechanisms are discussed.