Changes of liver functions after albendazole treatment in human gnathostomiasis.

Ninety-eight out-patients of the Hospital for Tropical Diseases, Bangkok with clinical diagnosis of cutaneous gnathostomiasis were studied. All patients were treated with albendazole at a dosage of 400 mg (two tablets) twice daily for 14 days. They were seen periodically on day 0, day 14, day 28, day 195 and 1 year after treatment with laboratory investigations for any side effects of the treatment. There was a statistically significant increase of total protein, albumin, alkaline phosphatase (ALP), aspartate aminotransferase (AST) and alanine aminotransferase (ALT) values when comparing the different periods. The abnormal results are clearly indicated in AST and ALT values (liver enzyme) especially on day 14 both male and female patients had highest levels. No significant association with time was found in ALP value.

Risk behaviours and comprehension among intravenous drug users volunteered for HIV vaccine trial.

Out of 91 volunteers enrolled for the HIV vaccine trial, only 33 volunteers were eligible for vaccination. Of 33 volunteers recruited, 59 per cent of them had incomes of more than 5,000 Baht/ month. The median duration of drug addicts was 15 years (range 1-26 years) and 42 per cent never used condoms during sexual intercourse. As far as consent comprehension was concerned, all of them understood.

Pasteur oral cholera vaccine: studies of reactogenicity, clinical acceptability and immunogenicity in human volunteers.

Pasteur cholera vaccine consists of isolated antigenic fractions from V. cholerae El Tor Ogawa and Inaba. Enteric coated microgranules were prepared from antigen lyophilisate. Three doses of this vaccine were administered orally to 19 healthy young Thai adults at one week intervals. None of the volunteers experienced untowards reactions. The vibriocidal antibody responses manifested a significant antibody rise (> or = 4 fold) to serovar Inaba in 8 vaccinees (42.1%) and Ogawa in 4 (21.1%). Five and 6 vaccinees (26.3% and 31.6%) showed a > or = 4 fold rise of IgG and IgA anti-LPS, respectively.

Albendazole stimulates outward migration of Gnathostoma spinigerum to the dermis in man.

Human gnathostomiasis is characterized by space-occupying inflammatory lesions and/or hemorrhage as a result of the migration of, very often, a single larva of Gnathostoma spinigerum. Intermittent cutaneous migratory swellings occurring over years is the most common manifestation and the rare cerebral invasion may be fatal. There are currently no effective anthelminthics for this infection. During a double-blind randomized placebo control trial evaluating the efficacy of albendazole in cutaneous gnathostomiasis at a dosage of 400 mg twice daily for two weeks, it was observed that gnathostome larvae tended to migrate outward as a result of the treatment so that they could be recovered by excisional biopsy or by picking with a needle. In the placebo-treated group (N = 40), no such migration was observed during the 8,470 patient-days of follow-up while in the albendazole-treated group (N = 41) there was one worm in an excisional biopsy done on day 16 and two worms were removed from the skin by the patients themselves on days 8 and 0. Assuming that the period of drug exposure of the gnathostomes was the 14 days of albendazole administration plus another washout period of 7 days (equivalent to 20 half-lives of the active detectable metabolite), the total patient-days of albendazole exposure was 830. The rate of outward migration of gnathostomes in the drug treated group (3 per 830 patient-days) was significantly (p < 0.0001) higher than in the placebo group (0 per 8,470 patient-days).(ABSTRACT TRUNCATED AT 250 WORDS)

Health status of Thai volunteers in a cholera vaccine trial.

One hundred and seventy-one male adults were screened in recruitment of volunteers for a cholera vaccine trial. A full medical history and a physical examination were performed on each subject. The percentages of subjects vaccinated against cholera and typhoid within twelve months were 4 and 1 per cent respectively, while 88 and 15 per cent respectively had been vaccinated more than a year. Biochemical screening revealed abnormal liver function tests in 40.7 per cent, specifically alkaline phosphatase (8%), glutamic oxaloacetic transaminase (8%), glutamic pyruvic transaminase (4.7%), total bilirubin (10%) and globulin (34%). Ten (6%) of the volunteers were positive for hepatitis B surface antigen (HBs-Ag). The total white cell count was elevated in 13.5 and 81.9 per cent had eosinophilia. Stool examination revealed infection with Hookworm (54.9%), Opisthorchis viverrini (29.8%), Strongyloides stercoralis (5.3%), Endolimax nana (3.5%), Giardia lamblia (5.3%) and Taenia saginata (2.9%). Few volunteers (13.4%) had abnormal microscopic examination of urine sediment. Only 57 subjects were considered suitable to be volunteers. Each of these subjects had no significant past medical, surgical or psychological illness. None had been vaccinated against cholera within the previous 12 months and no subject had abnormalities on physical examination or routine biochemical and haematological screening. The large number of subjects excluded from recruitment (67%) emphasized the importance of proper screening of volunteers for any vaccine trial.

Relationship of vibriocidal antibodies to history of cholera vaccination in Thai adult volunteers.

Vibriocidal antibodies were determined by microtechnique in 5 groups of Thai adult volunteers who had never received or had received cholera vaccination within one year, more than one to five years ago, more than five to ten years ago and more than ten years ago respectively. Detailed questionnaires about socioeconomic status, educational levels and environmental factors were presented to every volunteer. There were no differences statistically in incomes, educational levels and environmental factors among the groups. It was found that the reciprocal geometric mean titers of antibodies in volunteers who had never received cholera vaccination was generally low. The reciprocal geometric mean titers of the volunteers who had received cholera vaccination within one year were statistically different from other groups (p = 0.05). There was no correlation between blood groups of volunteers and vibriocidal antibodies.

Immune responses following killed whole vibrio-B subunit oral cholera vaccine in human volunteers.

Immunogenicity of killed whole vibrio and B subunit oral cholera vaccines in American and Thai volunteers were analysed in terms of significant rise of antibody titre. Three doses of 2 x 10(11) killed vibrios and 5 mg of cholera toxin B subunit were given at two-week intervals. There were no differences in the percent of volunteers with significant rise of serum immunoglobulin G and secretory immunoglobulin A (sIgA) to cholera toxin. However, the percent with significant rises of serum antibody to whole cell V. cholerae Inaba measured by vibriocidal titre and serum immunoglobulin G, and secretory immunoglobulin A to lipopolysaccharide (LPS) measured by ELISA in American volunteers were significantly different from those in Thai volunteers (89% VS 45%, 68% VS 9% and 53% VS 0%, respectively) (p less than 0.05).

Ultrasonographic study of the biliary system in opisthorchiasis patients after treatment with praziquantel.

Ultrasonographic examination of the liver and biliary system using a portable ultrasound unit was performed in 1987 in 647 opisthorchiasis patients who had been treated with praziquantel during 1981 to 1986. Treatments was repeated annually in those reinfected. The reinfection rate was 53.9% in the first year and gradually declined. Ultrasonographic findings were normal in 80.6% of subjects. The most common abnormal finding was liver enlargement (14.8%), followed by dilatation of the gallbladder (3.5%), sludge formation (2.1%) and thickening of the wall of the gallbladder (1.0%). Gallstones were found in 7 cases (1.0%). Dilatation of intrahepatic bile ducts was detected in one subject (0.1%). The incidence of gallstones in treated patients was similar to that reported in a large necropsy series of the general population. Prospective studies will be needed to further investigation the association between opisthorchiasis, treatment and gallstone formation.

Adherence of human eosinophils to infective filariform larvae of Necator americanus in vitro.

Eosinophilia is common in hookworm infection but the interaction between eosinophils and the larval stage of the parasite is poorly understood. The present study was conducted to test the ability of the eosinophils to adhere to infective filariform larvae of Necator americanus in vitro. Adherence of eosinophils to the larvae was found to be serum dependent. Antibody facilitated eosinophil adherence but this was maximal in the presence of complement. The adherence was greatly diminished by EGTA treated normal human serum (NHS) and was completely abolished when NHS was treated with either EDTA or heat-inactivation, suggesting that the process can be facilitated through complement activation via the alternative pathway. As with other nematodes, the surface of hookworm larvae appeared to be both antigenic and complement-activating. Although it is not known whether eosinophil adherence has any larvicidal effect, the present study demonstrated for the first time a definite interaction between human eosinophils and hookworm filariform larvae.

Effect of inosiplex on the humoral and cell-mediated immune responses to intradermal human diploid cell rabies vaccine.

Antigen-stimulated lymphocyte transformation was studied in recipients of intradermal human diploid cell rabies vaccine (HDCV). HDCV was administered intradermally at 8 different anatomical sites, 0.1 ml each, on day 0; followed by another 4-site injection on day 7. Rabies antigen-stimulated in vitro proliferative response was evident as early as 7 days after starting immunization. It reached a peak on day 14 and had declined by day 28. The cellular proliferative response preceded and roughly correlated with the antirabies antibody response. Simultaneous administration of inosiplex, an antiviral and immunopotentiating drug, during the first 10 days of intradermal HDCV immunization did not result in heightened antibody titres or cell-mediated immune response to the vaccine. The number of T cells and the lymphocyte proliferative response to phytohaemagglutinin in inosiplex-treated vaccinees were similarly not significantly different from untreated controls. Our results confirm other previous findings that a specific cell-mediated immune response can be consistently and rapidly induced by an intradermal regimen of HDCV immunization. The addition of inosiplex to this regimen did not enhance the humoral or cell-mediated immune responses to the vaccine. The apparent lack of immunostimulating effect of inosiplex in this setting may be the result of several factors such as the immunization schedule and the immunologic parameters examined.

ELISA for immunodiagnosis of human gnathostomiasis.

An ELISA for immunodiagnosis of human gnathostomiasis using a crude water extract of third-stage larvae of G. spinigerum as antigen, and alkaline phosphatase labelled goat antihuman IgG in the indicator system was developed and evaluated. At the titre of 1:400 and above positive results were observed in 100% of 4 parasitological confirmed and 10 eosinophilic meningo-encephalitis (EME) typical of gnathostomiasis cases, 56% of 160 cutaneous migratory swelling cases, 33% of 24 cases with EME typical of A. cantonensis infections, 23% of 92 cases with other parasitic infections and 1.5% of blood donors. The overall sensitivity was 59% and specificity 84%. The predictive value was 77%. The results indicated that ELISA is potentially useful for immunodiagnosis of gnathostomiasis but improvement of sensitivity and specificity is needed.

In vivo and in vitro studies of quinine sensitivity of Plasmodium falciparum in Thailand.

Forty-four patients with falciparum malaria were studied. Nine patients were given quinine orally at a daily dose of 1.5 gm base for a period of 14 days. The mean parasite clearance in all 9 patients was 3.3 days, and none had recrudescence in follow-up examinations for 31 days. The in vivo study of these 9 patients showed sensitivity to quinine which correlated with the in vitro test, with concentration of quinine base 2.5-5.8 microgram/ml of blood that inhibited the maturation of Plasmodium falciparum parasites. The results of the in vitro test of 35 patients showed concentrations of quinine base 2.1-5.4 microgram/ml of blood were able to inhibit the maturation of P. falciparum parasites. Therefore, these studies indicate that Plasmodium falciparum are still sensitive to quinine and quinine remains to be the drug of choice for the treatment of falciparum malaria in Thailand.