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In this model of liver transplantation, liver grafts were transfected with the El-deleted, replication-defective adenovirus vectors encoding the LacZ gene driven by the human CMV promoter, or the replication-defective retrovirus vectors encoding the human IL-7 and neomycin phosphotransferase genes. Liver grafts were perfused ex-vivo with either of these two vectors during cold preservation time. In adenovirus-mediated gene transfer, positive staining of the hepatocyte was recognized predominantly around the portal triads at post-operative day 2. Positive staining was observed until 14 days after transfection. In a retrovirus-mediated gene transfection, gene transfection was tested both in a whole-size and a reduced-size graft implantation of the liver because the retrovirus vector requires a replication of the target cells for gene transfection. In conclusion, adenovirus-mediated gene transfection to the liver graft during cold preservation time resulted in an effective expression of the transfected sequence. On the other hand, retrovirus vector required the reduction of the liver graft for a successful gene transfection., 論文

Since 1993, virological and seroepidemiological survey of arbovirus infections was conducted in pilot areas in Laos under the World Health Organization-Japan International Cooperation Agency-Laos trilateral Primary Health Care Project. Human sera were obtained at the laboratory in Khammouane Provincial Hospital, and at Sok Yai village in Vientiane Municipality, and antibodies to Japanese encephalitis (JE), dengue (DEN) and chikungunya (CHIK) viruses were assayed by neutralization test. The sera were classified according to the age groups. In Khammouane area, antibody-positive rates to DEN-1, 2, and 3 reached high (over 90%) by 11-15 years old and kept high thereafter. Antibody-positive rates to DEN-4 and JE increased with age and reached over 50% by 21-30 and 31-40 years old, respectively. In Sok Yai area, antibody-positive rates to DEN-2 and 3 were over 50% in all age groups. The positive rate of DEN-1 antibody reached 50% by 11-15 years old and increased with age. Although DEN-4 and JE antibody-positive rates fluctuated among age groups, they tended to increase with age. JE antibody survey in swine sera indicated that the JE virus was active during the rainy season. Positive rate of CHIK antibody tended to increase with age and reached over 50% in older age groups. These results indicate that DEN-1, 2, and 3 viruses are circulating more frequently in these areas. DEN-4, JE and CHIK viruses also exist with less activity. In terms of the primary health care for the prevention and control of arbovirus infections, the project team conducted health education and environmental sanitation in Sok Yai village. They also organized several training courses on the diagnosis and treatment of JE and DEN for junior doctors, health workers, and laboratory technicians.

Seroepidemiological survey of three arbovirus infections were conducted at Khammouane Province, Lao P.D.R. A total of 141 human sera were collected at the laboratory of Khammouane provincial hospital and examined for the antibodies to dengue (DEN), Japanese encephalitis (JE) and chikungunya (CHIK) viruses by neutralization test. Positive rates of antibodies to DEN-1,2 and 3 were high in the age groups older than 11-15 years old, while that of antibody to DEN-4 increased rather slowly with age. JE antibody-positive rate also increased with age and reached over 50% in 31-40 age group. CHIK antibody-positive rate increased with age and reached 50% in the age group over 51 years old. The results indicate that DEN viruses were widely circulating in this area. Although JE does not appear to be a big problem at the moment in this area, the circumstances indicate the possibility of becoming a JE epidemic area in future. Epidemiological surveillance must be continued., 論文

In 1979, 37 cases of dengue hemorrhagic fever (DHF) were reported to the Ministry of Health for the first time in Laos. In 1985, a total of 1,759 cases of DHF was reported as the first epidemic. In 1987, larger epidemics of DHF occurred with a total of 6,567 cases in the Vientiane Municipality and a total of 3,098 cases in four provinces. The morbidity rate of the outbreak in Vientiane was as high as 1,530/100,000. In the end of 1988, an Aedes Control Unit (ACU) was set up in the Vientiane Municipality to reduce the Aedes larva density and strengthen health education to the residents. Since 1989, DHF epidemic such as seen in 1985 or 1987 has not occurred in Vientiane so far. Activities of the ACU seem to be efficacious in reducing the larva density, judged by the Breteau and House indices obtained. However, another approach to show the reduction of dengue virus transmission has not been tried yet. In 1990, a seroepidemiological study on inhabitants in the Vientiane Municipality was performed. The results indicated followings: (1) The percentage prevalences of neutralizing (N) antibodies to dengue (DEN) 1-4 viruses increased with age, but the prevalences of N antibodies to DEN 3 and DEN 4 were lower than those to DEN 1 and DEN 2 viruses. (2) The geometric mean titer of N antibody to DEN 2 was highest among 4 serotypes in every age group. (3) By the age of 15 years, the majority (90%) of the inhabitants were infected with two or more serotypes of DEN virus., 熱帯医学 Tropical medicine 35(4). p219-227, 1994

We have constructed C-terminally truncated Japanese encephalitis virus envelope (E) proteins that ranged in length from 260 amino acids (a. a.) to 380 a. a. of the N-terminal sequence, using the baculovirus expression system, to analyze antigenic sites and examine basic conditions to keep a proper configuration of E protein. Truncated E proteins longer than 304 a. a. residues reacted with patients sera with sequential flavivirus infection, but failed to react with sera with primary flavivirus, even JE virus, infection. The E proteins of 279 a. a. or shorter residues did not react with sera from both patients with primary and sequential flavivirus infection. These results suggest that the main epitopes recognized during the secondary flavivirus infection are different from those recognized during the primary flavivirus infection, and also that existence of the fifth disulphide bond (a. a. #190 and a. a. #287) is involved in the reactivity of recombinant E proteins with patient sera in sequential flavivirus infection. Analysis of the length of expressed membrane (M) protein combined with E protein revealed that M proteins shorter than 37 a. a. residues failed to react with any of patient sera. This suggests that at least the C-terminal 37 a.a. residues of M protein is needed for the proper cleavage between M and E proteins.

A microscopic examination of a faecal specimens was designed to identify the enteropathogenic parasites in the diarrhoeal stool specimens in which neither enteropathogenic bacteria nor rotavirus was isolated in Caost Provincial General Hospital, Mombasa, Kenya. The parasites incriminated as causes of diarrhoea were Entamoeba histolytica, Giardia lamblia, Trichuris trichiura, hookworm and Ascaris lumbricoides. The cysts and ova of these parasites, however, were present with equal frequency in diarrhoeal, semi-formed and formed stool specimens, except the trophozoites of E. histolytica. The role of parasites in causation of diarrhoea is difficult to evaluate by the routine stool examination for parasites., 熱帯医学 Tropical medicine 35(1). p11-16, 1993