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Biomedical subjects

C H Chuang

Publications and source records attributed to C H Chuang.

13 recordsLinked to original sources
PubMed1992

Evaluation of efficacy of four pediculicides against head louse (Pediculus capitis) infestation.

To evaluate the efficacy and to determine the minimum effective dosage of four pediculicides against head louse infestation, as well as to select a safe, effective, practical, and cheap agent, 1,657 infested school children in 25 primary schools in Szu-Hu, Kou-Hu, and Ku-Keng Districts of Yunlin County were treated and 1,611 of them were examined. The overall cure rate was 73% and the rate for boys (84%) was higher than that for girls (71%). The cure rate of Nix (permethrin 1%) cream rinse was 81%. The cure rate for single dosages of 1, 2, 3 and 4 cases/tube (56 gm/tube) was 87%, 83%, 81% and 71%, respectively. The cure rate of Para aerosol (bioallethrine 0.66%) was 78%. The cure rate for single dosages of 30 and 40 cases/tube (90 gm/tube) was 87% and 70%, respectively. The cure rate of Prioderm (malathion 1%) cream shampoo was 64%. The cure rate for single dosages of 10, 15 and 20 cases/tube (40 gm/tube) was 74%, 71% and 52%, respectively. The cure rate of Delice (1% gamma benzene hexachloride) was 71%. The cure rate for single dosages of 5 and 10 ml/case was 64% and 76%, respectively. Of the 226 infested girls, 181 (80%) were found to be infested with 1-10 head lice, 33 (15%) with 11-50 lice, 7(3%) with 51-100 lice and 5 (2%) with over 100 lice. Of the 2,160 head lice collected, 1,788 (83%) were nymphs, 284 (13%) females, and 88 (4%) males. The mean number of head lice in each infested girl was 10 (range 1-137). The low cure rates obtained in the present study may be due to the fact that many school girl & have long hair. In comparison, Nix had the highest cure rate (81%) but the highest price (NT$ 120/case). The cure rate and price of Para aerosol (78%, NT$ 7.2/case) and Delice (71%, NT$ 16.7/case) came next. Prioderm (64%, NT$ 10.0/case) had the lowest rate and a slight offensive smell. Preliminary trials show that based on the cost-effectiveness, Para aerosol is best in head louse infestation control.

Allethrins↗
PubMed1991

Optical properties of normal, diseased, and laser photocoagulated myocardium at the Nd: YAG wavelength.

Laser photocoagulation of the myocardium effectively destroys arrhythmogenic foci. The purpose of this study was 1) to compare the optical properties of canine myocardium before and after photocoagulation, 2) to compare the canine model with clinical cases by measuring the optical properties of human myocardium, and 3) to assess the optical properties of human myocardial scar and epicardial fat tissue. Measured optical properties were the absorption coefficient, mu a; scattering coefficient, mu s; and scattering anisotropy factor, g. Optical measurements were performed at 1064 nm wavelength on thin plane parallel tissue slices using the integrating sphere method with glass hemispheres on either side of the sample. The study showed 1) an increase of the scattering coefficient by 40% and a two- to threefold increase in reduced scattering coefficient as a result of photocoagulation; 2) that the mu a (0.035 +/- 0.024 mm-1) and mu s (17.9 +/- 3.8 mm-1) of human myocardium were not significantly different from mu a (0.043 +/- 0.021 mm-1) and mu s (17.3 +/- 2.2 mm-1) of canine myocardium, whereas the human g (0.964 +/- 0.005) was slightly different from the canine g (0.974 +/- 0.008); and 3) that the mu a (0.021 +/- 0.016 mm-1) of epicardial fat and mu s (13.8 +/- 1.1 mm-1) of myocardial scar were significantly lower than those of normal myocardium. A dynamic model of laser-tissue interaction incorporating these changes and inhomogeneities is necessary to better describe light distribution during laser photocoagulation.

Animals↗
PubMed1991

Evaluation of root quality of Bupleurum species by TLC scanner and the liver protective effects of "xiao-chai-hu-tang" prepared using three different Bupleurum species.

A simple and quick quantitative analysis of saikosaponins a, c and d, the major bioactive principles contained in Bupleurum species, by TLC scanner is described. Results with Bupleurum kaoi, the species native to Taiwan, showed that the roots, rhizomes and aerial parts (leaves and stem) have greater quantities of saikosaponins than cultivated B. falcatum var. komarowi and imported B. chinense. The liver protective effects of water extracts of "Xiao-Chai-Hu-Tang" (XCHT), a mixture of seven crude drugs, prepared using roots of the three different Bupleurum species and aerial parts of B. kaoi and B. falcatum var. komarowi, were evaluated using CCl4-induced toxicity in rats. The acute increase of serum transaminase (SGOT and SGPT) levels caused by CCl4 administration (3.0 ml/kg, s.c.) was dramatically reduced when treated with XCHT prepared with the roots of B. kaoi. The histological metamorphoses such as fatty changes, ballooning degeneration, cell necrosis and lymphocyte and Kupffer cell increases around the central vein, were clearly decreased by XCHT prepared with B. kaoi. Furthermore, water extracts of aerial parts of both B. kaoi and cultivated B. falcatum var. komarowi decreased SGOT and SGPT levels and moderately reduced the pathological changes.

Animals↗
PubMed1991

Anatomical and histological studies of Bupleuri radix.

Three kinds of Bupleuri Radix were found in Taiwan. To clarify their origins, histological studies were carried out to identify their internal and external structures. It was found that Bupleuri Radix or "Chai-hu" of Taiwan is derived from roots of the following species" 1, Bupleurum chinense which was imported from China, 2, Bupleurum falcatum var. komarowi a cultivated production of Japanese origin, and 3, Bupleurum kaoi which is indigenous to Taiwan. These Bupleuri Radix were easily assigned by anatomical characteristics and their qualitative analysis of active principle - saikosaponin were established by TLC.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1991

Effects of vascular runoff on myointimal hyperplasia after mechanical balloon or thermal laser arterial injury in dogs.

BACKGROUND: Clinical evidence suggests that poor vascular runoff reduces the long-term success rate of femoral angioplasty procedures. The purpose of this experimental study was to examine myointimal hyperplasia of dog femoral arteries after balloon denudation, thermal laser arterial injury, or sham operation in normal and reduced vascular runoff conditions. METHODS AND RESULTS: Before mechanical balloon injury or transluminal heated laser probe motion, the peripheral vascular runoff of dogs was reduced by ligating the femoral artery below its three distal side branches, decreasing the femoral flow rate from 114 +/- 9 to 52 +/- 5 ml/min (mean +/- SEM). Endothelial denudation with a predominantly intact elastic internal membrane and circumferential structural changes in the media were noted by light microscopy 1 hour after balloon injury. Focal completely necrotic lesions of intima and media were found 1 hour after thermal laser arterial injury. After 8 weeks, the maximal thickness of neointima plus media of the site of previous intervention was greater after balloon injury (0.45 +/- 0.03 mm) and thermal laser injury (0.54 +/- 0.03 mm) than after sham operation (0.40 +/- 0.01 mm; p less than 0.001) in normal runoff dogs. Reduced vascular runoff augmented myointimal hyperplasia both in the balloon-injured and thermally damaged arteries; the wall thickness increased from 0.45 +/- 0.03 to 0.93 +/- 0.10 mm and from 0.54 +/- 0.03 to 0.65 +/- 0.05 mm, respectively (p less than 0.001). The neointimal and medial wall area of the balloon-injured arteries contributed 48% to the area encompassed by the external elastic membrane compared with an 81% portion when vascular runoff was reduced (p less than 0.01). A 47% neointimal and medial wall area was found in thermally injured arteries with normal runoff compared with 63% after runoff reduction (p less than 0.05). CONCLUSION: This study suggests that hemodynamic factors associated with poor vascular runoff play an important role in extending myointimal hyperplasia independent of method and severity of the arterial injury during angioplasty.

Animals↗
PubMed1991

Current status of malaria in Taiwan from 1966 to 1990.

Malaria was highly or moderately endemic in about 200 townships among the 360 municipalities in Taiwan before the World War II. During and after the War, annual incidence of malaria was estimated as 1.2 million cases out of 6 million population at that period. In 1952, malaria mortality was reported as 27.5 per 100,000 persons. Malaria Eradication Program in Taiwan was successfully carried out during 1947-1965 through a combined effort made by the Government, WHO, UNICEF and USAID, and by the participation of the community. Since 1966, avoidance of malaria transmission in population centers has been well maintained through the network of malaria surveillance system, both parasitological and entomological, at the ports (sea and air) of entry and by the 383 public health services all over the island. Through this surveillance network, a total of 936 malaria cases and distribution of the vector mosquito Anopheles minimus have been well documented during 1966- June 1990. Of the 936 malaria cases detected, 819 cases were classified as imported from outside the country, 14 cases as relapsing, 17 cases as induced infection through blood transfusion, and 86 cases as the secondary infection originating from the imported cases. These 86 cases were exclusively P. vivax infections which were found concealed in the mountainous area of the northern most of Taiwan during 1968-1973. This small transmission focus was swiftly eliminated without further dissemination to the other parts of the island. Of the 819 imported cases; 250 cases were P. falciparum infection, 516 cases were P. vivax, 19 cases were P. malariae, 18 cases were P. ovale and 16 cases were mixed infection of P. falciparum with other parasite species. among the imported malaria cases with P. falciparum (in total 266), six were reported fatal cases before proper diagnose and treatment. Of the 14 relapsing cases; 13 cases were P. malariae infection, and the remaining one case was P. vivax malaria. All the 17 induced malaria cases were caused by the blood transfusion, exclusively with P. malariae infection. It was quite difficult to prove the positive parasitemia directly under microscopy from the blood donors due to very low parasite density of their blood.

Humans↗
PubMed1990

Hepatitis D virus infection among intravenous drug abusers in Taiwan: analysis of risk factors and liver function tests.

To investigate the prevalence of hepatitis D virus (HDV) and hepatitis B virus (HBV) infection among intravenous drug abusers in Taiwan, a total of 761 male prisoners, including 680 intravenous drug abusers, were studied for serological markers of HBV and HDV. Questionnaires were distributed to evaluate the risk factors for HDV infection and also to estimate the strength of association among HDV infection and the risk factors. HBV infection was common, and the positive rates of HBV markers between intravenous drug abusers and non-drug abusers were not statistically different. However, the positive rate of the antibody to HDV was significantly higher among intravenous drug abusers than among non-drug abusers (21.3% vs. 8.6%). Of 131 chronic HBV carriers with intravenous drug abuse, 119 (91%) were anti-HD positive. Using multiple logistic regression models, we found that the most important risk factor for HDV infection was hepatitis B surface antigen (HBsAg) carriage, and intravenous drug addiction the next. A matched case-control study also was conducted to compare liver function tests among both anti-HD- and HBsAg-positive group anti-HD-negative, and HBs-AG-positive group as well as those with neither positive. Statistically significant difference in liver function tests was not found. It is concluded that the HBsAg carriers with intravenous drug abuse in Taiwan are commonly HDV infected with and that the infection does not seem to affect the liver as assessed by liver function tests.

Adult↗
PubMed1988

Efficacy of a mass hepatitis B vaccination program in Taiwan. Studies on 3464 infants of hepatitis B surface antigen-carrier mothers.

To evaluate the efficacy of the mass hepatitis B vaccination program in Taiwan in interrupting perinatal hepatitis B virus transmission, 3464 randomly selected 18-month-old infant vaccinees born to hepatitis B surface antigen-carrier mothers were recruited from 9697 eligible infants during a six-month period of the program. They were divided into ten groups according to maternal infectivity and compliance with the vaccination schedule. Serum samples were tested for hepatitis B surface antigen, antibody to hepatitis B surface antigen, and antibody to hepatitis B core antigen. In 786 infants who had highly infectious mothers and who received hepatitis B immune globulin and vaccine on schedule, the protective efficacy was about 85%. The efficacy seemed to be slightly lower in those immunized off schedule. Overall, 11% of infants still carried hepatitis B surface antigen, and 81% of the infants had antibody to hepatitis B surface antigen that exceeded 10 mIU/mL in more than 90% of them. The geometric mean titers of antibody to hepatitis B surface antigen were more than 200 mIU/mL in every group of infants. We conclude that the mass vaccination program is efficacious in preventing perinatal hepatitis B virus transmission and the chronic carrier state; most infant vaccinees have adequate levels of protective antibody at 18 months of age. This program is extremely significant in the control of hepatitis B virus infection in Taiwan.

Carrier State↗
PubMed1985

Sequential uptake patterns of technetium-99m pyrophosphate in hepatoma.

Sequential liver scintiphotography with Tc-99m pyrophosphate (PYP) was used to prospectively evaluate its uptake patterns in hepatoma. The scintiphotos and time-activity curves of 40 cases were analyzed. Two distinct patterns of tumor activity were noted: gradual but complete extraction and trapping of Tc-99m PYP in hepatoma in 38% of the patients (group 1), and absence of subsequent Tc-99m PYP uptake in hepatoma after initial blood pool activity in 62% of the patients (group 2). Since extraction and trapping of Tc-99m PYP occur approximately in two fifths of the patients with hepatoma, we conclude that Tc-99m PYP liver scintigraphy is not worthwhile supplementing the conventional radionuclide studies for diagnosing hepatoma, even in the selected patients in the countries where the prevalence of hepatoma is high.

Carcinoma, Hepatocellular↗
PubMed1979

Changes in mitochondrial DNA in cardiac hypertrophy in the rat.

We studied DNA (mtDNA) replication in adult female rat hearts undergoing hypertrophy secondary to constriction of the ascending aorta. MtDNA was measured in isolated mitochondria by a fluorometric method adapted for that purpose. The conditions for removal of contaminating nuclear DNA were developed, and the purity of the mtDNA was assessed from its molecular conformation (open and closed circles) and by renaturation-kinetic analysis. The mtDNA concentration in mitochondria, expressed as micrograms of DNA per milligram of mitochondrial protein, increased 2, 4, and 7 days postoperatively by 21, 73, and 98%, respectively. Similar results were obtained when mtDNA was expressed per nonomole of cytochrome a. The population of replicative intermediates of mtDNA was analyzed by electron microscopy. In normal hearts, we observed molecular forms characteristic of animal mtDNA, such as circular monomers and dimers, catenated molecules, D-loops, expanded D-loops, and gapped molecules. D-loop frequency, which was near 50% in the mtDNA of control hearts, was markedly reduced to 5-7% in hypertrophying hearts. This result indicates that the increase in replicative flux of mtDNA is associated with the removal of a block in the conversion of D-loops to other intermediates.

Animals↗
PubMedDate not supplied

Thermal laser arterial injury and prostacyclin administration in dogs: thrombotic and hyperplastic consequences.

Angioplasty is considered as an alternative to surgical reconstruction of arteriosclerotic vessels especially since lasers and atherectomy devices have become clinically available. However, the resulting arterial injury may lead to acute thrombotic occlusion and chronic restenosis because of hyperplastic vascular repair. The purpose of this experimental study was to evaluate the consequences of thermal laser arterial injury on platelet deposition and myointimal hyperplasia in dog femoral arteries. An intraarterial, short-term prostacyclin (PGI2) infusion was given to evaluate the antithrombotic and antiproliferative effects of this drug. Severe arterial necrosis, partly carbonized and vacuolized, extending to the adventitia was induced by a transluminal heated laser probe motion. The platelet deposition after one hour was 33.62 +/- 6.56 (x 10(6)/cm2.) (mean +/- SEM) without prostacyclin, after 40 ng/kg/min prostacyclin (PGI2) 24.70 +/- 5.45 and after 400 ng/kg/min 9.3 +/- 2.26 (p less than 0.005 no PGI2 vs 400 ng/kg/min PGI2). Myointimal hyperplasia was present eight weeks after thermal laser vascular injury independent of the initially administered prostacyclin. In conclusion, acutely thrombotic and chronically hyperplastic femoral arteries were found following transluminal thermal arterial injury in dogs. Prostacyclin administration could be clinically beneficial in reducing acute vascular thrombosis following thermal angioplasty. Short-term use of this substance, however, may not prevent a hyperplastic response to angioplasty.

Angioplasty, Laser↗