Showing papers by "Taipei Veterans General Hospital published in 1987"

Drug release from tablets containing cellulose acetate phthalate as an additive or enteric-coating material.

Abstract: A formulation containing cellulose acetate phthalate for preparing enteric-coated granules was developed with the use of granulation and microencapsulation techniques. Drug release from tablets or tableted microcapsules was measured in a disintegration apparatus and an in vitro variable-pH release simulator of the flow type. The release mechanism for the tablets or tableted microcapsules was determined with the Higuchi matrix model, a first-order kinetic model, and the Weibull distribution function. Adding acetone directly to the mixture of sulfamethoxazole and cellulose acetate phthalate resulted in enteric-coated granules with more prolonged release than other granulation methods. Microencapsulation of the granules significantly delayed the drug release and enhanced the effectiveness of the enteric coating. Microencapsulated granules show release patterns that are sustained and can be simulated with three different release models, i.e., with square-root time plotting, diffusional first-order plotting, and Weibull distribution plotting. The enteric-coating behavior of the tablets was more clearly demonstrated with the variable-pH release stimulator than with a fixed-pH dissolution method.

Hepatitis B virus infection of cord blood leukocytes.

Abstract: The presence of hepatitis B virus (HBV) DNA in the serum and leukocytes obtained from the peripheral blood of 24 mothers and from the cord blood of their newborns was determined by hybridization procedures. HBV DNA was not detected in the serum and leukocytes of six HBsAg-, HBeAg-negative and two HBsAg-positive, HBeAg-negative mothers and their newborn infants. Among the 16 HBeAg-positive carrier mothers, HBV DNA was found in 13 cases (81%) in the serum and in two cases (12%) in leukocytes. Though the viral DNA was not present in sera, it was detected in two of the 16 cord blood leukocyte samples. In follow-up studies, these two infants did not seroconvert up to 15 months of age and they became carriers with elevated serum alanine aminotransferase levels. The results suggest that HBV may be transmitted vertically and such in utero infection may have resulted in immune tolerance leading to a carrier state.

Biosynthesis of mevinolin, a hypocholesterolemic fungal metabolite, in Aspergillus terreus.

Abstract: Mevinolin and compactin are fungal metabolites which inhibit cholesterol biosynthesis in mammalian systems. Biogenetically, mevinolin is formed from polyketide chains, one 18-carbon and one 4-carbon, derived from acetate in normal head to tail fashion. The remaining two carbons in mevinolin, namely C-2' and C-6 methyl groups, are transferred from S-adenosylmethionine. To distinguish the timing and sequence of these two methylation steps, [Me-14C]- and [Me-3H,14C]-L-methionine were fed to Aspergillus terreus at several selected production intervals. Location and distribution of labels were determined by the specific chemical degradation methods. The results have demonstrated clearly that transfer of methyl groups from two S-adenosylmethionine molecules to the biosynthetic precursors of mevinolin was a sequential process. Methylation at C-6 preceded that at C-2' of mevinolin. Both methylation steps proceeded with complete retention of hydrogens. Methyl groups were probably transferred to the anion-like intermediates.

In vitro release behaviour of theophylline from PIB-induced ethylcellulose microcapsules interpreted by simple mathematical functions.

Abstract: Theophylline microcapsules were prepared by phase separation using polyisobutylene as a coacervation-inducing agent. The release rate was dependent on the molecular weight of the polyisobutylene used. A simple mathematical function has been used for the quantitative description of the release process of the drug from PIB-induced microcapsules. It was found that 1/y = A(1/x)+ B is the best for interpreting the release process of microcapsules, since the values of the constants A and B are proportional to the amount of the drug released.

Type I primary hyperoxaluria associated with type I renal tubular acidosis.

Abstract: An 8-year-old boy who had suffered from recurrent stone formation since the age of 4 years, was admitted as an emergency due to anuria for a half day on November 20, 1986. Kidney-ureter-bladder film showed that the urethra was obstructed by a stone, and emergent cystoscopy was performed to remove it. He is the product of consanguinous marriage, his parents being first cousins. There was no family history of renal stone. Laboratory investigations showed hypokalemic, hyperchloremic metabolic acidosis. The ammonium chloride loading test revealed inability to acidify the urine and a markedly decreased excretion of titrable hydrogen ion and ammonium ion in the urine. These results indicate that this is a case of Type I renal tubular acidosis. His 24-hour urinary excretion of oxalate and glyoxylate were also markedly increased. There were no underlying causes leading to the development of secondary hyperoxaluria. These results also establish the diagnosis of Type I primary hyperoxaluria. The patient then received regimens of Polycitra 1ml/kg/day and Vitamin B6 50mg/day for 4 months. However, urinary stone developed again in this patient 4 months later. To our knowledge, Type I primary hyperoxaluria in association with Type I renal tubular acidosis has not been previously reported.

Immunohistochemical studies of colorectal carcinoma with a monoclonal antibody against carcinoembryonic antigen

Abstract: Immunoperoxidase localization of carcinoembryonic antigen (CEA) was performed on tissue sections of colorectal carcinoma using a monoclonal antibody (MAb) against CEA. CEA has been demonstrated in 20 out of 22 rectum carcinomas (90.9%), in all of 23 colonic carcinomas, in none of 4 hyperplastic polyps and in 2 out of 6 adenomatous polyps (33.3%). CEA was found more often, and the intensity of the staining was stronger in well-differentiated carcinomas than in moderately and poorly differentiated carcinomas. No correlation was found between the presence of CEA in colorectal carcinoma and the stages of the disease. The mean values of serum CEA in patients with colorectal carcinoma and polyps with negative, weakly and strongly positive staining were 5.4 +/- 3.9 ng/ml, 28.3 +/- 23.8 ng/ml and 99.8 +/- 145.3 ng/ml respectively. Elevation of serum CEA occurred in 30 out of 39 (78.9%) cases with strongly positive CEA staining, in 4 out of 6 (66.7%) with weakly positive and in 1 out 9 (11.1%) with negative staining. A significant difference was found in serum CEA activity between the group with negative CEA staining and positive CEA staining (P less than 0.01). Our results suggest that the monoclonal antibody (MAb C27) can be used for the localization of CEA in conventionally prepared tissues of colorectal carcinomas by immunoperoxidase techniques for routine immunopathological diagnosis.