Single domain m-plane ZnO grown on m-plane sapphire by radio frequency magnetron sputtering

High-quality m-plane orientated ZnO films have been successfully grown on m-plane sapphire by using radio frequency magnetron sputtering deposition. The introduction of a nanometer-thick, low-temperature-grown ZnO buffer layer effectively eliminates inclusions of other undesirable orientations. The structure characteristics of the ZnO epi-layers were thoroughly studied by synchrotron X-ray scattering and transmission electron microscopy (TEM). The in-plane epitaxial relationship between ZnO and sapphire follows (0002)(ZnO) [parallel] (112[overline]0)(sapphire) and (112[overline]0)(ZnO) [parallel] (0006)(sapphire) and the ZnO/sapphire interface structure can be described by the domain matching epitaxy along the [112[overline]0](ZnO) direction. The vibrational properties of the films were investigated by polarization dependent micro-Raman spectroscopy. Both XRD and micro-Raman results reveal that the obtained m-ZnO layers are under an anisotropic biaxial strain but still retains a hexagonal lattice.

Immunosuppressive effects and mechanisms of leflunomide in dengue virus infection of human dendritic cells

BACKGROUND

Dengue virus (DENV) infection is a serious public health issue without specific treatment. We examined the potential immunomodulatory effects of leflunomide, a dihydroorotate dehydrogenase inhibitor commonly prescribed for arthritis, in DENV-stimulated monocyte-derived dendritic cells (mo-DCs).

METHODS

mo-DCs were prepared from purified monocytes. Cytokine and chemokine concentrations were determined by enzyme-linked immunosorbent assay. Expression of cell surface markers or viral E protein was measured by flow cytometry. The activation of transcription factors and kinases was determined by electrophoretic mobility shift assays, Western blotting, or immunoprecipitation kinase assays. Chemotaxis assays were used to determine cell migration.

RESULTS

Leflunomide at therapeutic concentrations inhibited cytokine and chemokine production from DENV-infected mo-DCs. Leflunomide suppressed mo-DC maturation by downregulating the expression of both CD80 and CD86. In addition, leflunomide inhibited DENV-induced mo-DC migration and mo-DC response to chemoattractants CCL19 and CCL21. Inhibition of mo-DC migration was likely due to the suppression of CCR7 expression on mo-DCs. These events were associated with the suppression of nuclear factor kappa B and activator protein-1 signaling pathways by leflunomide.

CONCLUSIONS

Leflunomide preserves immunosuppressive effects, inhibiting activation of DENV-stimulated mo-DCs. Leflunomide may be helpful in the development of therapeutics for DENV infection.

Propionic acid fermentation of lactose by Propionibacterium acidipropionici: effects of pH

Batch propionic acid fermentation of lactose by Propionibacterium acidipropionici were studied at various pH values ranging from 4.5 to 7.12. The optimum pH range for cell growth was between 6.0 and 7.1, where the specific growth rate was approximately 0.23 h(-1). The specific growth rate decreased with the pH in the acids have been identified as the two major fermentation products from lactose. The production of propionic acid was both growth and nongrowth associated, while acetic acid formation was closely associated with cell growth. The propionic acid yield increased with decreasing pH; It changed from approximately 33% (w/w) at pH 6.1-7.1 to approximately 63% at pH 4.5-5.0. In contrast, the acetic acid yield was not significantly affected by the pH; it remained within the range of 9%-12% at all pH values. Significant amounts of succinic and pyruvic acids were also formed during propionic acid fermentation of lactose. However, pyruvic acid was reconsumed and disappeared toward the end of the fermentation. The succinic acid yield generally decreased with the pH, from a high value of 17% at pH 7.0 to a low 8% at pH 5.0 Effects of growth nutrients present in yeast ex-tract on the fermentation were also studied. In general, the same trend of pH effects was found for fermentations with media containing 5 to 10 g/L yeast extract. However, More growth nutrients would be required for fermentations to be carried out efficienytly at acidic pH levels.

The solution structure of [d(CGC)r(amamam)d(TTTGCG)]2

The solution structure and hydration of a DNA.RNA hybrid chimeric duplex [d(CGC)r(amamam)d(TTTGCG)]2 in which the RNA adenines were substituted by 2'-O-methylated riboadenines was determined using two-dimensional NMR, simulated annealing, and restrained molecular dynamics. Only DNA residue 7T in the 2'-OMe-RNA.DNA junction adopted an O4'-endo sugar conformation, while the other DNA residues including 3C in the DNA.2'-OMe-RNA junction, adopted C1'-exo or C2'-endo conformations. The observed NOE intensity of 2'-O-methyl group to H1' proton of 4am at the DNA.2'-OMe-RNA junction is much weaker than those of 5am and 6am. The 2'-O-methyl group of 4am was found to orient towards the minor groove in the trans domain while the 2'-O-methyl groups of 5am and 6am were found to be in the gauche (+) domain. In contrast to the long-lived water molecules found close to the RNA adenine H2 and H1' protons and the methyl group of 7T in the RNA-DNA junction of [d(CGC)r(aaa)d(TTTGCG)]2, there were no long-lived water molecules found in [d(CGC)r(amamam)d(TTTGCG)]2. This is probably due to the hydrophobic enviroment created by the 2'-O-methylated riboadenines in the minor groove or due to the wider minor groove width in the middle of the structure. In addition, the 2'-O-methylation of riboadenines in pure chimeric duplex increses its melting temperature from 48.5 degrees C to 51.9 degrees C. The characteristic structural features and hydration patterns of this chimeric duplex provide a molecular basis for further therapeutic applications of DNA.RNA hybrid and chimeric duplexes with 2'-modified RNA residues.

Comparison of sexual behaviors between male homosexuals and male heterosexuals in Taiwan

BACKGROUND

Homosexuality and sexual behavior have attracted great attention in the acquired immunodeficiency syndrome (AIDS) epidemic. This study primarily explores the risky behaviors and patterns of sexual behavior of male homosexuals in Taiwan.

METHODS

Comparison study methodology was adopted. Ninety-two male homosexuals, as the study group, were recruited from gay bars and gay organizations, and 91 male heterosexuals, with similar ages and educational levels, were recruited as a control group for comparison. Semi-structured interviews were carried out and anonymous questionnaires were self-administered.

RESULTS

(1) The mean age at the time of first sexual intercourse of the study group was younger than that of the control group. (2) The rate of having two or more sexual partners in the study group was significantly higher. (3) However, the rate of condom use during recent intercourse was higher in the control group than in the study group. (4) Sexual knowledge and attitudes toward sexuality in the study group were more open, but their sexual desires, as rated by the questionnaire, were more suppressed than those of the control group. (5) In terms of courtship, the study group was less constrained by the social values of marriage and tended to separate sex from love.

CONCLUSION

Similar to western studies, our study found that the study group in Taiwan adopted more risky sexual behaviors. Each group had its particular sexual behavioral pattern and subculture of sexuality. However, a longitudinal follow-up study with ethnographic perspective is necessary for a more sophisticated understanding of the trends and changes of sexual behavior in homosexuals.

The solution structure of [d(CGC)r(aaa)d(TTTGCG)](2): hybrid junctions flanked by DNA duplexes

The solution structure and hydration of the chimeric duplex [d(CGC)r(aaa)d(TTTGCG)](2), in which the central hybrid segment is flanked by DNA duplexes at both ends, was determined using two-dimensional NMR, simulated annealing and restrained molecular dynamics. The solution structure of this chimeric duplex differs from the previously determined X-ray structure of the analogous B-DNA duplex [d(CGCAAATTTGCG)](2)as well as NMR structure of the analogous A-RNA duplex [r(cgcaaauuugcg)](2). Long-lived water molecules with correlation time tau(c)longer than 0.3 ns were found close to the RNA adenine H2 and H1' protons in the hybrid segment. A possible long-lived water molecule was also detected close to the methyl group of 7T in the RNA-DNA junction but not with the other two thymines (8T and 9T). This result correlates with the structural studies that only DNA residue 7T in the RNA-DNA junction adopts an O4'-endo sugar conformation, while the other DNA residues including 3C in the DNA-RNA junction, adopt C1'-exo or C2'-endo conformations. The exchange rates for RNA C2'-OH were found to be approximately 5-20 s(-1). This slow exchange rate may be due to the narrow minor groove width of [d(CGC)r(aaa)d(TTTGCG)](2), which may trap the water molecules and restrict the dynamic motion of hydroxyl protons. The minor groove width of [d(CGC)r(aaa)d(TTTGCG)](2)is wider than its B-DNA analog but narrower than that of the A-RNA analog. It was further confirmed by its titration with the minor groove binding drug distamycin. A possible 2:1 binding mode was found by the titration experiments, suggesting that this chimeric duplex contains a wider minor groove than its B-DNA analog but still narrow enough to hold two distamycin molecules. These distinct structural features and hydration patterns of this chimeric duplex provide a molecular basis for further understanding the structure and recognition of DNA. RNA hybrid and chimeric duplexes.

Hydration of [d(CGC)r(aaa)d(TTTGCG)](2)

We have studied the hydration and dynamics of RNA C2'-OH in a DNA. RNA hybrid chimeric duplex [d(CGC)r(aaa)d(TTTGCG)](2). Long-lived water molecules with correlation time tau(c) larger than 0.3 ns were found close to the RNA adenine H2 and H1' protons in the hybrid segment. A possible long-lived water molecule was also detected close to the methyl group of 7T in the RNA-DNA junction but not to the other two thymine bases (8T and 9T). This result correlates with the structural studies that only DNA residue 7T in the RNA-DNA junction adopts an O4'-endo sugar conformation (intermediate between B-form and A-form), while the other DNA residues including 3C in the DNA-RNA junction, adopt C1'-exo or C2'-endo conformations (in the B-form domain). Based on the NOE cross-peak patterns, we have found that RNA C2'-OH tends to orient toward the O3' direction, forming a possible hydrogen bond with the 3'-phosphate group. The exchange rates for RNA C2'-OH were found to be around 5-20 s(-1), compared to 26.7(+/-13.8) s(-1) reported previously for the other DNA.RNA hybrid duplex. This slow exchange rate may be due to the narrow minor groove width of [d(CGC)r(aaa)d(TTTGCG)](2), which may trap the water molecules and restrict the dynamic motion of hydroxyl protons. The distinct hydration patterns of the RNA adenine H2 and H1' protons and the DNA 7T methyl group in the hybrid segment, as well as the orientation and dynamics of the RNA C2'-OH protons, may provide a molecular basis for further understanding the structure and recognition of DNA.RNA hybrid and chimeric duplexes.

[Concerns and nursing care of a family living with AIDS]

AIDS is not solely a medical issue but also has profound implications for family relationships. This case report using the concepts of family nursing and case management presents the concerns of a family living with AIDS. The data was collected through continuous contacts with a patient during December 1994 to August 1996. This report's findings indicate that the concerns of the family living with AIDS fall into seven categories: The reasons for HIV infection, how to meet the patient's sexual needs, suffering during health care seeking, the effectiveness and side-effects of anti-viral drugs, home care skills, the light of hope, death issues. Professional nurses should provide care to both the AIDS patient and the family members. Using social resources and cooperating with other health professionals can promote the quality of life for families living with AIDS.

Current seroepidemiology of hepatitis D virus infection among hepatitis B surface antigen carriers of general and high-risk populations in Taiwan

In order to assess the current seroepidemiology of hepatitis D virus (HDV) infection in Taiwan where hepatitis B virus (HBV) is hyperendemic, a total of 756 voluntary blood donors, 641 prostitutes, 1,014 patients with sexually transmitted diseases (STDs), and 628 drug abusers were studied. Radioimmunoassays were used for testing HBV infection markers and antibody against HDV (anti-HDV) among HBsAg carriers. The anti-HDV prevalence among HBsAg carriers was significantly higher in STD patients (9.6%), prostitutes (33.1%), and drug abusers (68.1%) than in blood donors from the general population (2.2%). The prevalence gradually increased with age in blood donors and STD patients, but reached a plateau at a young age in prostitutes and drug abusers. Males had a higher prevalence than females in blood donors (2.7% vs. 0), STD patients (8.2% vs. 7.5%), and drug abusers (69.0% vs. 57.1%), but the difference was not statistically significant. STD patients with syphilis had a higher prevalence (19.5%) than those affected with non-ulcerating STDs (5.3%). While unlicensed prostitutes had a lower prevalence (13.6%) than licensed prostitutes (44.9%), intravenous drug abusers had a higher prevalence (73.1%) than non-intravenous drug abusers (34.6%). There was a twofold increase in anti-HDV prevalence from 1986 to 1989 among prostitutes, but the prevalence remained unchanged in the general population and drug abusers. HDV infection remains limited to the high-risk groups and spread mainly by promiscuity and needle sharing in Taiwan.

Generation of neutrophil-chemoattractant by degradation of tumor cell membrane protein

Polymorphonuclear leukocytes (PMN) infiltrating into tumors are assumed to be the result of a migration in response to a tumor-derived chemotactic factor. It is hypothesized that tumor-derived chemotactic factors, which are supposed to be in aggregates, can be exposed by proteolytic degradation of the tumor cell membrane protein (TCM). The TCM suspension made from either Sarcoma 180 or Ehrlich ascites tumor after incubation with Varidase at 37 degrees C for six to eight weeks is referred to as a degraded TCM protein (DTCM). The purpose of this study was to detect whether or not the DTCM was chemotactic for PMNs. Chemotactic activity was assayed by a sponge-matrix model and expressed in the number of PMNs infiltrating into the sponge per mouse after intrasponge injection of the DTCM, dose range, 0.4-0.005 mL. Maximal response to DTCM was restricted to the limited dose between 0.01 and 0.02 mL. Quantities of DTCM > 0.02 mL caused a response in roughly reciprocal proportion to the dose of DTCM. Changes in the circulating leukocyte count in response to an intravenous (i.v.) injection of DTCM was biphasic. The initial relative leukopenia was followed by leukocytosis within 24 hours in rats surviving the effect of DTCM doses < 0.5 mL. However, in rats with i.v. injections of higher doses, profound leukopenia was present at death. The mice, after an intraperitoneal (i.p.) injection of DTCM, dose range, 0.5-1.0 mL, died between 16 and 24 hours after the injection. The bone marrow of these mice showed complete depletion of PMNs.(ABSTRACT TRUNCATED AT 250 WORDS)

Hepatitis B virus e antigen and primary hepatocellular carcinoma

Serum samples from 243 cases of primary hepatocellular carcinoma (PHC) and 302 non-PHC hospital controls were tested for hepatitis B virus (HBV) surface antigen (HBsAg), antibody to HBsAg (anti-HBs), antibody to HBV core antigen (anti-HBc), HBV e antigen (HBeAg) and antibody to HBeAg (anti-HBe) with radioimmunoassays using commercial kits. A total of 236 (97%) PHC cases and 302 (100%) hospital controls were positive for one or more HBV markers. While 188 (77%) PHC cases and 57 (19%) controls were positive for HBsAg, 44 (18%) PHC cases and 5 (2%) controls were positive for both BHsAg and HBeAg. Statistically significant associations with PHC were observed for HBsAg and HBeAg with an odds ratio (OR) of 10.0 and 3.2, respectively, when age, sex and other markers were adjusted. The stratification analysis of interactive effects of HBV infection markers on the development of PHC showed that HBeAg carrier status may increase PHC risk associated with HBsAg status.

Role of atrial natriuretic peptide in hemoconcentration during exercise

Changes in plasma levels of atrial natriuretic peptide (ANP) and albumin, and blood hematocrit (Hct) during treadmill exercise were studied in 6 healthy men before and after beta-adrenergic blockade. Plasma ANP levels increased during exercise and then gradually decreased. There was a concomitant increase in both Hct and plasma albumin concentrations. Prior administration of a long-acting propranolol, 160 mg daily for 3 consecutive days, markedly elevated plasma ANP levels before, during and after exercise. In addition, the mean basal Hct increased significantly and further rose during exercise after propranolol administration. When increments in plasma ANP concentrations during exercise in individual subjects were compared with those in Hct, there was a significant positive correlation between the two variables before and after propranolol administration. The results indicate a close relationship between the changes in plasma ANP and those in Hct during exercise at different ANP levels, and suggest that ANP may be at least one of the factors involved in the hemoconcentration associated with exercise.

Preparation of spherical encapsulation of activated carbons and their adsorption capacity of typical uremic toxins

A method has been designed for making spherical microencapsulation of activated-carbon particles for use in the removal of metabolic wastes and/or toxins from blood. This bench-scale method was able to make better uniformity in particle size, and at a higher particle production rate. The material properties such as particle size, particle porosity, electromicroscopy of surface morphology, surface hardness, and pore-size distribution were characterized in order to conclude with their adsorption capacity for specific toxin solutes. The performance characteristics of these self-prepared particle encapsulation was also evaluated against the commercially available hemoperfusion particles, e.g., Kuraray's DHP (Japan). The encapsulation particles were also coated with polyhydroxyethyl methacrylate (PHEMA) for blood compatibility purpose.

[MAC-ELISA for the detection of IgM antibodies to dengue type I virus (rapid diagnosis of dengue type I virus infection)]

The commercial rapid diagnostic reagents for Dengue virus infection is still not available at present. An ABC MAC-ELISA (Avidin Biotin Complex IgM Antibody Capture Enzyme Linked Immunosorbent Assay) for the detection of Dengue type I virus infection has been described. IgG purified from high titer (HI = 2560) human anti-flavivirus serum is labelled with biotin for the rapid diagnosis of Dengue type I virus infection. 389 serum specimens of suspected Dengue Fever patients including 226 HI(+) paired sera and 163 HI(-) paired sera which were collected from 1 to 150 days after onset of the disease in 1988 have been assayed for IgM antibodies to Dengue type I virus. Cut off value is based on the mean of OD490 of 162 Dengue negative serum specimens plus 4 SD. The positivity of IgM antibody increased as the viremia disappeared and IgM antibody for Dengue-1 serum specimens collected 9 days after onset of the disease is 100% detectable.

[Concentration changes in PCB isomers in the blood in patients with PCB poisoning]

The blood of 3 yu-cheng patients sampled from 1980 to 1985 and of 14 yusho patients sampled from 1982 to 1988 were analyzed for 7 polychlorinated biphenyl (PCB) isomers by gas chromatography with a capillary column. The concentrations of PCBs in yu-cheng patients were up to 400 ppb and much higher than those of yusho patients. The high concentration of PCBs were decreased at biological half lives of about 50 months and 2,4,3',4'-tetra-CB and 2,4,5,3',4'-penta-CB were first decreased with time at half lives of about 12 months. Therefore, peculiar gas chromatographic pattern for yusho patients would be formed 3 years after the onset. The concentration and patterns of blood PCBs of yusho patient kept in similar levels during 1982 to 1988.

Hepatitis B virus markers in Chinese twins

Chinese same-sex twins were recruited in order to study the distribution of different markers of hepatitis B virus (HBV) infection, including HBV surface antigen (HBsAg), antibody to HBV core antigen (anti-HBc), antibody to HBsAg (anti-HBs), HBV e antigen (HBeAg) and antibody to HBeAg (Anti-HBe), as well as to compare the concordance of these markers in pair-wise fashion among monozygotic (MZ) and dizygotic (DZ) twins and singleton controls. A total of 289 pairs of MZ twins, 102 pairs of DZ twins and 375 pairs of age-sex-matched singleton controls were studied. More than 50 percent of the members of each group (64.71% of MZ twins, 51.96% of DZ twins and 62.13% of controls) were found to be infected with HBV. In general, the patterns of the response to HBV infection in the 3 groups were similarly distributed. 20.17% of the members of the 3 groups (21.45% of MZ twins, 14.22% of DZ twins, and 20.80% of controls) were HBsAg carriers. Among the HBsAg carriers, 49.19% (44.35% of MZ twins, 34.48% of DZ twins and 55.77% of controls) were HBeAg carriers. No significant difference in the concordance of HBV infection was observed in the MZ and DZ twins. However, highly significant differences were noted between MZ twins and controls, and between DZ twins and controls. Highly significant differences were also observed in the concordance of carrier status between MZ and DZ twins and between MZ twins and controls, but not between DZ and controls. As for the other HBV markers, no significant differences were observed. It is concluded that the genetic influence in response to HBV infection markers is not well-characterized and requires further study.

A one-compartment single-pore model for extracorporeal hemoperfusion

A one-compartment single-pore model is proposed for the dynamic analysis and performance evaluation of a hemoperfusion column under operation. Experimental data obtained from binary systems containing creatinine and uric acid may be well predicted by the theoretically computed curves. This theory offers a means for the preclinical evaluation of any prototype hemoperfusion column.

A case-control study of primary hepatocellular carcinoma in Taiwan

A case-control study was carried out to explore possible risk factors of primary hepatocellular carcinoma (PHC) in Taiwan. One hundred thirty-one PHC patients and 207 hospital control patients were interviewed and blood samples were collected for blood type and hepatitis B virus (HBV) infection marker tests. Eighty-three percent of the PHC patients were found to be hepatitis B surface antigen (HBsAg) positive as compared with 21.0% of the control patients with an odds ratio (OR) of 21.5. Hepatitis B e antigen (HBeAg) positive status increased the risk of PHC. No significant association was observed between erythrocyte genetic markers and PHC, except c of the Rh system, which was significantly lower in the PHC cases. As compared with the control patients, the PHC patients had a higher proportion with a history of liver diseases and more siblings affected with liver diseases. However, the variables such as cigarette smoking, alcohol drinking, peanut consumption, frequent intake of raw fish, heart diseases, peptic ulcer, malaria, hypertension, diabetes, color blindness, G-6-PD deficiency, surgical operation, blood transfusion, and liver diseases of parents and children were not found to be associated with PHC.

Effect of beta-adrenergic blockade on plasma levels of atrial natriuretic peptide during exercise in humans

Effect of beta-adrenergic blockade on plasma levels of atrial natriuretic peptide (ANP) during treadmill exercise was studied in 9 healthy volunteers. Plasma ANP levels increased during exercise. The mean plasma ANP concentration on 12-min exercise (32.5 +/- 3.7 pg/ml, mean +/- SEM) was significantly higher than the control (16.7 +/- 1.0 pg/ml). After exercise, the levels decreased and the mean plasma ANP concentrations in the recovery period were higher in subjects in the sitting position than in subjects who kept standing. Prior administration of a long-acting propranolol, 160 mg daily for 3 consecutive days, augmented ANP release during exercise. The mean plasma ANP concentrations on 9- and 12-min exercise (34.5 +/- 3.1 and 64.9 +/- 15.0 pg/ml, respectively) were significantly higher than those in the corresponding exercise stage without propranolol. Plasma ANP levels in the recovery period also increased after the administration of propranolol and the subjects in the sitting position again had higher plasma levels than those in the standing position. These results suggest that increased central blood volume during exercise elevates atrial pressure to stimulate ANP secretion, and that greater atrial distension and pressure due to reduced ventricular contractility by beta-adrenergic blockade facilitates ANP release to a greater extent.

A mass vaccination program in Taiwan against hepatitis B virus infection in infants of hepatitis B surface antigen-carrier mothers

To combat hepatitis B virus (HBV) infection in Taiwan, a mass immunoprophylaxis program was launched on July 1, 1984, aiming first at prevention of chronic HBV carriage from perinatal mother-to-infant infection. In the first 15-month period, 352,721 (78%) of 450,585 pregnant women were screened for hepatitis B surface antigen (HBsAg); HBsAg was present in 62,359 (18%), with 50% of them categorized as highly infectious. Infants born to HBsAg-positive women were given 5 micrograms of a plasma-derived hepatitis B vaccine at ages 1, 5, and 9 weeks, with a booster at age 12 months. Infants of highly infectious carrier mothers received an additional 0.5 mL of hepatitis B immune globulin within 24 hours after birth. The coverage rate of the hepatitis B immune globulin was 77% in 27,375 infants born to highly infectious mothers, and that of the first, second, third, and the fourth doses of vaccine was 88%, 86%, 84%, and 71%, respectively, in infants of 55,620 carrier mothers. The reported untoward reactions to immunization were negligible. We conclude that a mass hepatitis B vaccination program is feasible in hyperendemic areas such as Taiwan; this should be a significant step toward the effective control of HBV infection in these areas.

Potent induction of human placental mono-oxygenase activity by previous dietary exposure to polychlorinated biphenyls and their thermal degradation products

Placental tissues were obtained from women in Taiwan who had ingested rice oil contaminated with aromatic polychlorinated hydrocarbons 3-4 years before conception. Known contaminants in the rice oil were polychlorinated biphenyls and their thermal degradation products, including polychlorinated dibenzofurans and polychlorinated quaterphenyls. Placental homogenates showed large increases in mono-oxygenase enzymes, including aryl hydrocarbon hydroxylase, 7-ethoxycoumarin O-de-ethylase, and diol, quinone, and phenolic metabolites of benzo(a)pyrene (analysed by high performance liquid chromatography). The findings suggest that exposure to these widespread, environmental pollutants may exert substantial and persistent metabolic effects.

Discovery and epidemiology of PCB poisoning in Taiwan: a four-year followup

An outbreak of polychlorinated biphenyl (PCB) poisoning from the consumption of contaminated rice oil, covering four counties in central Taiwan, was investigated. There were 1843 cases by the end of 1980. The highest frequency of incidence occurred during the period from March to July 1979. The severity of clinical manifestations varied. Most patients showed symptoms of mild or moderate severity. The major age group affected was between 11 and 20 years old. Most of the victims were students and factory workers. The amount of PCB intake in each victim was estimated to be 0.7 to 1.84 g and the latent period from the time of intake to the onset of clinical manifestations was approximately 3 to 4 months. The patients' blood PCB concentrations ranged from 3 ppb to 1156 ppb; 44.27% of 613 patients had levels of 51 to 100 ppb and 27.6% PCB blood levels over 100 ppb. In the course of 3.5 years, 2061 persons were determined to be PCB poisoning victims. Now, except for a few severe cases, their skin symptoms are very much improved. Thirty-nine babies showing hyperpigmentation were born from PCB-poisoned mothers. The fatality rate was high: eight of them died. Another 24 deaths were reported among the PCB-poisoned group, almost half of them (12) from hepatoma, liver cirrhosis or liver diseases with hepatomegaly.

Outbreak of paralytic poliomyelitis, Taiwan

Taiwan had been free of major poliomyelitis outbreaks since 1975, but from May 29 to Oct 26, 1982, 1031 cases of type 1 paralytic poliomyelitis were reported to the Taiwan health authorities. Before the outbreak approximately 80% of infants had received at least 2 doses of trivalent oral poliovaccine (OPV) by their first birthday. Of the 86% of poliomyelitis patients whose vaccination status was known 65% had not had poliovaccine, 19% had received one dose, 8% had received two doses, and 8% had received three or more doses. Vaccine efficacy was calculated to be 82% after one dose, 96% after two doses, and 98% after three or more doses. Failure to vaccinate rather than vaccine failure was the most important risk factor in this outbreak. A child who had not had any vaccine was 80 times more likely to become a case than one who had received three or more doses of poliovaccine, independent of sanitation facilities at home. A child was 5 times more likely to become a case if he received water from non-municipal rather than municipal sources. Furthermore, for children who received municipal water, the risk was doubled if the family shared a toilet with at least one other family. This outbreak shows that major epidemics can occur in areas that have high overall community vaccination levels. Identification and vaccination of subpopulations with low coverage is essential for the control of poliomyelitis.

Role of polychlorinated dibenzofuran in yusho (PCB poisoning)

In the blood of 15 patients with yusho or "polychlorinated biphenyl poisoning" that occurred in 1979 in Taiwan, was found polychlorinated dibenzofurans (14 of 15) and polychlorinated quaterphenyls (15 of 15), as well as polychlorinated biphenyls (15 of 15). The mean concentration ratio of these substances was approximately 1 : 160 : 500. Based on the following evidence, we propose that polychlorinated quaterphenyls were major pathogenic substances in the development of yusho: (1) Clinical manifestations and course of yusho patients are disproportionately severe and persistent for the observed blood levels of polychlorinated biphenyls, while patients who were occupationally exposed to pure polychlorinated biphenyls take characteristically mild and benign clinical course despite polychlorinated biphenyl levels often much higher than those noted in yusho patients; (2) Polychlorinated debenzofurans show a marked tendency to accumulate in the liver, which might explain frequent presence of jaundice and other abdominal symptoms in yusho, which are, again, not observed in those with occupational polychlorinated biphenyl poisoning; (3) Toxicity of polychlorinated dibenzofurans is a hundred to ten thousand times greater than that of polychlorinated biphenyls and polychlorinated quaterphenyls in animal experiments.

Drug resistance among Mycobacterium tuberculosis strains isolated in Taiwan during 1975

455 strains of Mycobacterium tuberculosis were isolated from patients with history of treatment in Taiwan Provincial Tuberculosis Control Bureau and tested for resistance against various antituberculosis agents including streptomycin (SM), paraaminosalicylic acid (PAS), isoniazid (INH), cycloserine (CS), prothionamide (1321TH), kanamycin (KM), ethambutol (EMB), and rifampicin (RFP). In vitro resistance to SM and INH was more frequently found than others and the resistance to a single drug was more common than multiple resistance.

Japanese encephalitis surveillance in China (Province of Taiwan) during 1968-1971. I. Geographical and seasonal features of case outbreaks

During 1968-1971 Japanese encephalitis (JE) surveillance was conducted with WHO-assisted programs in Taiwan area. Emphasis was placed on: (1) active case-finding by hospital visits; (2) blood collection from every patient at the suitable time; and (3) the enforcement of standard diagnostic criteria on the results of hemagglutination-inhibition tests. Each year, approximately 90% of reported patients were etiologically examined. JE virus etiology was established in 277 (1968), 279 (1969), 269 (1970) and 158 (1971) cases. Despite the apparent concentration of cases in several cities, practically all the cultivated plains and basins were established as potentially endemic for JE. JE outbreak is found to have been clearly associated with season, not only in subtropical but also in tropical Taiwan. Each year it occurred consistently in mid-July in the southernmost county, 2-3 weeks after the peak of rice transplantation and its duration was a few weeks. On the western side of the island, although less consistently, JE outbreak seems to occur one to three weeks later than in the south. Outbreak in eastern Taiwan was a mid-September phenomenon for 3 years. Observed seasonal lag, which was significant between two neighboring localities on same latitude, suggests that paddy water management is more directly related to date of outbreak than local climate. Seasonal characteristics further suggests that the area may be separated into eight ecologic subdivisions. JE-virus transmission to a man during April at temperatures below the average of 20 C was discussed.

Japanese encephalitis surveillance in China (Province of Taiwan) during 1968-1971. II. Age-secific incidence in connection with Japanese encephalitis vaccination program

A baseline age/morbidity pattern for Japanese encephalitis (JE) epidemic in China (Province of Taiwan) in the 1960s was sought in JE surveillance. The pattern is characterized by: (1) high incidence in age groups 2-4 years, (2) moderately high incidence in age groups 5-7 years, (3) negligible incidence in children under 1 year of age as well as in adults, and (4) the variability of relative height of peak incidence co-incident with the JE-epidemic size in situ. Concurrently with surveillance, a JE-vaccination program was implemented by the Government. The children of target age groups received two doses of vaccine each during April. Vigilant supervision was given to the campaign to achieve a high coverage rate with two-dose vaccination and meticulous record-keeping. During 1969-1972, 2-year olds were the exclusive target; 52.2% (1969), 71.5% (1970), 74.5% (1971), and 83.0% (1972) of the target age group were covered. A considerable change from the baseline age/morbidity pattern seen in 1968 occurred during the above period. The comparison of epidemicity-adjusted incidence by year indications that incidence reduction in the 2- and 3-year old children in 1971 were substantial and suggests the possible impact of vaccination. The total JE incidence for the period 1968-1971 appears to be much lower in vaccinated population (23 reported and 8 confirmed/0.9 million) than in unvaccinated population (1,330 reported and 679 confirmed/2.2 million).

The effect of vaccination with a live attenuated strain of Japanese encephalitis virus on stillbirths in swine in Taiwan

Since an excellent candidate strain (M) for live virus vaccination of swine against Japanese encephalitis was developed, a number of large vaccination programmes have been implemented in Japan with the aim of controlling Japanese encephalitis epidemics in man by reducing the population size of nonimmune swine. Encouraging results have been obtained but no studies have been made on the benefits of live-virus vaccination to the industry. In order to determine the effect of vaccination upon the number of stillbirths occurring in the Japanese encephalitis post-emergence season, a total of 74 vaccinated, and subsequently mated, gilts at a large breeding farm in subtropical Taiwan were subjected to follow-up observations in comparison with a control group. The total incidence of litter stillbirths in the vaccinated group (1/74) was significantly lower than that in the control group (21/68). Over 92% of the newborn piglets from the vaccinated gilts were healthy, while 31.6-54.1% of the newborn piglets in the control groups were stillborn. The litter size of vaccinated gilts was larger than that of the control gilts. The vaccine was shown by tests in 22 swine to have an adequate degree of safety. Four weeks after vaccination with either 10(5.6) or 10(8.0) smicLD(50) of virus, all the swine developed an adequate level of antibody. The results indicate that live virus vaccination could benefit the industry in addition to achieving the main aim of controlling Japanese encephalitis viraemia in swine.