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Biomedical subjects

T Tan

Publications and source records attributed to T Tan.

At least 127 records · Page 7Linked to original sources
PubMed1984

Intrahepatic assembly of very low density lipoproteins. Phosphorylation of small molecular weight apolipoprotein B.

The possibility that apo-B is phosphorylated was examined using cultured rat hepatocytes. Rabbit antiserum prepared against rat apo-B was found to specifically react with both large and small molecular weight apo-B (by electroblotting assay and by immunoprecipitation of [35S]methionine-labeled proteins synthesized and secreted by hepatocytes). Following a 4-h incubation with [35P]orthophosphate, immunoprecipitation, and sodium dodecyl sulfate electrophoresis, an autoradiographic band corresponding to small molecular weight apo-B was obtained from cells and medium. Compared to the relative abundance of 32P which was associated with secreted small molecular weight apo-B, there was little (if any) detected in large molecular weight apo-B. Addition of excess unlabeled apo-B (obtained from rat serum) totally competed with the specific antiserum for this radioactive protein, indicating it was antigenically related to apo-B. Moreover, isolation of the 32P-labeled apo-B electrophoretic band, followed by acid hydrolysis and phosphoamino acid analysis, showed that at least 20% of the 32P originally associated with small molecular weight apo-B was in the form of phosphoserine. Control experiments ruled out the possible contamination of apo-B with phospholipid as well as the possibility that the phosphoserine produced by acid hydrolysis could have been derived from phosphatidylserine. To examine the relevance of these data to the in vivo state, rats were injected with [32P]orthophosphate. Immunoprecipitation of their livers followed by autoradiographic analysis showed the presence of 32P in small molecular weight apo-B. These data show for the first time that small molecular weight apo-B is synthesized as a phosphoserine containing protein.

Amino Acids↗
PubMed1984

Biopharmaceutical studies on hydantoin derivatives. IV. Factors affecting bioavailability of 5,5-diphenylhydantoin in dog.

Several factors affecting the bioavailability of 5,5-diphenylhydantoin (I) and its sodium salt (I-Na) were examined in dogs in relation to meal and following results were obtained. The bioavailability of I was not appreciably affected by the volume of coadministered water in the range of 30-120 ml. The bioavailability of I was most excellent when I was administered 0.5 h after meal. Food intake 0.5 h after drug administration enhanced appreciably the bioavailability, but that 2 h after drug administration did hardly affect the bioavailability. The extent of bioavailability of I-Na was almost 100% of the dose in the range of 100-400 mg/dog when it was administered 0.5 h after meal. While, when I-Na was administered in the fasting state, the extent of bioavailability was about 60% of the dose. Food-induced enhancement of the bioavailability of I was independent of the food constituents. The bioavailability of I was increased about 1.5-fold and 2-fold with 10-fold increase in the specific surface area of I, in the nonfasting and the fasting states, respectively. In the experiments using the dogs with the chronically implanted fistula in the common bile duct, it was found that the bile was not a major factor contributing to the food-induced enhancement of the bioavailability of I. There was a good correlation between the bioavailability of I in dog and that in man.

Adult↗
PubMed1983

Immunofluorescence studies of pemphigus and pemphigoid in Singapore.

Immunofluorescence studies (direct and indirect) were done on 48 cases of pemphigus and 55 cases of bullous pemphigoid. All cases of pemphigus had in vivo and in vitro IgG intercellular antibodies except for two patients whose sera were not sent for pemphigus antibodies. 47 (85.4%) of our pemphigoid patients had linear C3 deposits on the basement membrane zone while 29 (52.7%) had IgG deposition. Only 17 (30.9%) patients had circulating pemphigoid antibodies. The results were compared and discussed with those reported by other earlier authors.

False Negative Reactions↗
PubMed1982

Biopharmaceutical studies on hydantoin derivatives. II. Pharmacokinetics and bioavailability of hydantoin derivatives in dogs.

Pharmacokinetics and bioavailability for the 1-benzenesulfonylhydantoin derivatives and 1-unsubstituted hydantoin derivatives were evaluated from the plasma concentrations after oral and intravenous administrations to dogs. Apparent volume of distribution of the 1-benzenesulfonylhydantoin derivatives was about 0.25 l/kg, while that of the 1-unsubstituted hydantoin derivatives was about 1.3 l/kg. The result suggests that introduction of the benzenesulfonyl group at 1-position of the hydantoin ring has marked effect on the distribution into the fluids and tissues of the body. Bioavailabilities of sodium 5,5-diphenylhydantoin and sodium 1-benzenesulfonyl-5,5-diphenylhydantoin exceeded those of their corresponding free forms. The results were well explicable in terms of the excellent dissolution behaviours of the salt forms. The bioavailabilities of 5-ethyl-5-phenylhydantoin and 1-benzenesulfonyl-5-ethyl-5-phenylhydantoin were almost perfect. The results suggest that the dissolution rate is a rate-determining step in the bioavailability of the derivatives having two phenyl groups at 5-position of the hydantoin ring, irrespective of the presence of the benzenesulfonyl group at 1-position.

Administration, Oral↗
PubMed1982

Biopharmaceutical studies on hydantoin derivatives. III. Physico-chemical properties, dissolution behavior, and bioavailability of the molecular compound of 1-benzenesulfonyl-5,5-diphenylhydantoin and antipyrine.

Physico-chemical properties, dissolution profiles, and bioavailability of the molecular compound composed of equimolar amount of 1-benzenesulfonyl-5, 5-diphenylhydantoin (BSDH) and antipyrine were studied. The spectral and thermal analyses suggest that the intermolecular force in the molecular compound is attributed to the hydrogen bond between 3-NH of BSDH and 5-C = 0 of antipyrine. In the aqueous media, the molecular compound decomposed to the constituents and there was no interaction between them. The dissolution behavior of BSDH from the molecular compound was characteristic, the high supersaturation being present for a long time, while the dissolution of antipyrine from the molecular compound was slow and continued for a long time. The dissolution profile of the molecular compound was truly reflected on the bioavailability in dogs. With respect to BSDH, the rate and the extent of bioavailability of the molecular compound were excellent. On the other hand, the absorption of antipyrine from the molecular compound was sustained for a long time. BSDH and antipyrine had no influence one another on the intrinsic rate constant of transport through the intestinal membrane and on the pharmacokinetic constants such as the volume of distribution and the elimination rate constant.

Administration, Oral↗
PubMed1981

HLA and psoriasis in the Chinese.

The HLA locus A, B and C antigen frequency of 70 unrelated Chinese patients with psoriasis were compared to that of 330 normal subjects. The frequency of 1, Aw30 and B13 were significantly elevated among patients compared to normals, even after correction for the number of antigens typed for. The joint occurrence of Aw30, B13 was observed in 20/70 (37.1%) patients compared to 8/330 /2.4%) normals (chi 2 = 60.7, RR = 16.1). Aw30 and B13 were found to be in significant linkage disequilibrium in patients as well as normals.

China↗
PubMed1981

Biopharmaceutical studies on hydantoin derivatives. I. Physico-chemical properties of hydantoin derivatives and their intestinal absorption.

The physico-chemical properties of a series of hydantoin derivatives and their intestinal absorption from solution were studied. The introduction of the benzenesulfonyl group at the 1-position of the hydantoin ring greatly affects the physico-chemical properties: the acid dissociation constants were increased 1000-fold and the partition coefficients were increased 100- to 1000-fold in the chloroform/water system and 10- to 100-fold in the n-octanol/water system. The solubilities of 1-benzenesulfonylhydantoin derivatives increased with increasing pH of the solution at pH more than 5, but the solubilities of the 1- unsubstituted hydantoin derivatives were scarcely dependent on the pH of the solution in the pH 1 to 8 region. The intestinal absorption from solution was found to be caused by the passive transport according to the first-order kinetics. The rate constants of absorption of 1-benzenesulfonylhydantoin derivatives were rather large even under the condition where they were 99% ionized in the solution than that of the corresponding 1-unsubstituted hydantoin derivatives which exist mainly as the unionized from under the same condition. The intestinal absorption from a solution and the partitioning to chloroform produced linear free energy relationships to each other for the 1-benzenesulfonylhydatoin derivatives and for the 1-unsubstituted hydantoin derivatives independently. However when the partition coefficients in the n-octanol/water system were applied, the hydroxyl derivatives were found to deviate from linear relationships. On the basis of the results, a suggestion was made on the in vivo behavior and the bioavailability.

Animals↗
PubMed1981

A case of primary cutaneous cryptococcosis successfully treated with miconazole.

An 81-year-old man with primary cutaneous cryptococcosis of the left forearm was treated with intravenous and oral miconazole nitrate. Culture for Cryptococcus became negative within three weeks. The ulcer healed within 25 days after treatment was started. Follow-up examination 1 1/2 years later showed no evidence of recurrent infection.

Administration, Oral↗
PubMed1981

Leprosy.

Leprosy is still a medical problem in the tropical and subtropical countries in Africa, Asia and South and Central America. New evidence on the airborne transmission of the disease is presented. The rest of the review deals with the clinical manifestations, the use of anti-leprosy drugs, and the treatment of reactions. Prophylaxis by BCG and chemoprophylaxis are briefly discussed.

BCG Vaccine↗
PubMed1979

HLA and sexually transmitted diseases in prostitutes.

The HLA profile of 148 unrelated, Chinese prostitutes (56 with repeated gonococcal infection, 31 with syphilis, 31 with gonorrhoea and syphilis, and 30 with no evidence of infection) was compared with that of 238 unrelated, healthy, Chinese control subjects. The joint occurrence of AW19 B17 was observed in 25.8% of prostitutes with double infections compared with 6.7% of control subjects, while that of A11 B15, on the other hand, was associated with a resistance to syphilis and gonorrhoea. The latter profile was observed in 46.7% of prostitutes in business for more than two years who were resistant to disease, in 30% of prostitutes with an overall disease resistance, in 13.4% of control subjects, and in only 3.2% of prostitutes with combined syphilis and gonorrhoea. Because of the statistical uncertainty when multiple variables are being analysed these studies should be repeated in other groups of prostitutes of the same and different ethnic origins.

Adolescent↗
PubMed1976

The effect of collagenase on surface markers of human peripheral lymphocytes.

The effect of collagenase on the 'T' and 'B' markers of peripheral blood lymphocytes was studied in five healthy male blood donors. No significant difference between untreated and collagenase treated lymphocytes was found. Collagenase is recommended for use in liberating living cells from skin biopsy specimens.

B-Lymphocytes↗
PubMed1971

Participation of three cell types in the anti-sheep red blood cell response in vitro. Separation of antigen-reactive cells from the precursors of antibody-forming cells.

Spleen cells of unprimed CBA mice were shown to produce anti-sheep red blood cell antibodies comparable in amount in vivo and in vitro. Under identical culture conditions spleen cells of C57BL mice did not respond. CBA spleen cells, passed through columns of cotton wool (CBAf), were equally inactive in vitro. However combined cultures containing both CBAf and C57BL cells yielded as many or more plaque-forming cells than the same number of unfractionated CBA spleen cells. Analysis of the contribution of each cell population to the synthesis of antibody in the combined cultures has disclosed the participation of three cell types. A thymus-dependent, radiosensitive cell was derived from the CBAf population, while the C57BL was the source of the precursor of the antibody-forming cell and of a radioresistant cell. The latter two were partially separated in a Staput apparatus.

Animals↗
PubMedDate not supplied

Endothelial function evaluated by flow-mediated dilatation in pediatric vascular disease.

The endothelial function of children with and without vascular disease, consisting of 41 controls, 24 with Kawasaki disease (KD), and 46 with diabetes mellitus (DM), was examined. Age at examination ranged from 3 to 23 years (mean, 12.0 +/- 4.7). The flow-mediated dilatation (FMD) and intima-media complex in the common carotid artery were measured. In controls age at examination was not associated with FMD or intima-media complex. FMD significantly decreased in children with KD and DM compared with the control group (control vs KD or DM: 11.7 +/- 14.7 vs 3.0 +/- 11.0 or 6.4 +/- 8.5%, respectively; p < 0.05). However, there was no significant difference for intima-media complex among the groups. Furthermore, FMD in KD patients with coronary arterial aneurysm was lower than that in KD patients without aneurysm (-0.5 +/- 9.2 vs 8.3 +/- 9.1%, p < 0.05). In DM patients, FMD in the high HbA1c group (HbA1c = 7%) was lower than that in the normal HbA1c group (HbA1c < 7%) (4.8 +/- 8.1 vs 11.4 +/- 7.8%, p < 0.05). In conclusion, FMD detected endothelial impairment in children with KD or type 1 DM regardless of overt vascular complications, and FMD impairment occurs prior to intima-media complex thickening. By measuring both FMD and intima-media complex, useful information for predicting vascular complications may be obtained.

Adolescent↗
PubMedDate not supplied

Supplemental nitrogen inhalation therapy in very low-birth-weight infants with patent ductus arteriosus.

Very low-birth weight infants with patent ductus arteriosus (PDA) accompanied by severe heart failure do not respond to indomethacine therapy. It is essential to stabilize the general condition of these infants until surgical intervention. We tried to regulate the pulmonary blood flow to control congestive heart failure by administering supplemental nitrogen inhalation therapy to six very low-birth-weight infants with PDA. After the inhalation of supplemental nitrogen gas was begun, the arterial oxygen saturation and partial oxygen pressure immediately decreased. Furthermore, the blood pH, systolic pressure, and urine output significantly increased. The infants were well stabilized. Furthermore, there were no complications related to nitrogen gas inhalation. Supplemental nitrogen inhalation therapy is an effective and feasible therapy for severe congestive heart failure in very low-birth-weight infants with PDA.

Ductus Arteriosus, Patent↗
PubMedDate not supplied

Ceftriaxone for treatment of primary syphilis in men: a preliminary study.

Eighteen male patients with primary syphilis were randomly assigned to one of the following treatment schedules: ceftriaxone (3 g in a single intramuscular [im] injection), ceftriaxone (2 g im daily for two days), ceftriaxone (2 g im daily for five days), and benzathine penicillin (2.4 X 10(6) units in a single im injection). The single 3-g dose of ceftriaxone cured three men, one had a sustained response, and one failed to be cured. Of the patients given 2 g of ceftriaxone im daily for two days, three were cured and two had a sustained response. All three men treated with 2 g of ceftriaxone daily for five days had a sustained response. In the group given penicillin, three men were cured, one had a sustained response, and one was lost to follow-up.

Adolescent↗