Biomedical subjects

K Son

Publications and source records attributed to K Son.

28 records · Page 2Linked to original sources

PubMed1994

Characterization of the antigen 85 complex fibronectin-binding proteins derived from aged culture filtrates of Mycobacterium bovis BCG, Tice substrain.

The antigen 85 complex are major T-cell and B-cell antigens and fibronectin-binding proteins secreted by Mycobacterium tuberculosis, M. leprae and attenuated M. bovis (BCG vaccine). The Ag 85 complex was found to comprise a high proportion of the extracellular protein in filtrates of surface-pellicle cultures of Tice-substrain BCG vaccine, attaining a maximum of 25%. This proportion began to decrease prior to the end of the logarithmic growth phase, about 3 weeks after the start of the culture, mainly due to apparent degradation of the Ag 85 complex. Isolation of the main Ag 85 protein and determination of the first 36 residues of the NH2-terminus showed identity with the 85A protein isolated by others from various mycobacteria. Both the Ag 85A and B components were secreted in nearly constant proportions over a 6-week period. No Ag 85C protein was detected.

Amino Acids↗

PubMed1992

Mixed micelles as proliposomes for the solubilization of teniposide.

The aqueous solubility of teniposide in detergent and phospholipid mixed micelles was investigated as functions of the detergents and lipids composing the mixed micelles, the molar ratio of detergent to phospholipid, and the total lipid concentration of the system. The polarity, the charge of the phospholipid, and its saturation affected the solubilization potential of the micelles. Physical chemical factors such as the pH, ionic strength, and temperature of the dispersion medium also altered the solubilization capacity of the system. The results are explained by the changes occurring in the critical micelle concentration and packing arrangements of the aggregates. The desired solubility of teniposide can be achieved by adjusting the studied parameters to the optimum values. Teniposide-containing mixed micelles were spontaneously converted to drug-containing vesicles upon aqueous dilution; therefore, the precipitation of the drug was totally eliminated. In conclusion, mixed micelles as proliposomes can be a suitable drug carrier system for insoluble compounds such as teniposide.

Blood Proteins↗

PubMed1991

Multicenter study of superficial bladder cancer treated with intravesical bacillus Calmette-Guerin or adriamycin. Results of long-term follow-up.

We evaluated 158 cases of patients with superficial bladder cancers (Stages Ta, T1, and Tis). These cases were treated with either intravesical bacillus Calmette-Guerin (BCG) (Tice strain) or Adriamycin (ADR), in a multicenter, nonrandomized study. One hundred thirty-one of these patients were followed up; the results continue to show a higher percentage of initial complete remissions with BCG (68%) than with ADR (57%). With additional therapy, both BCG and ADR achieved complete remission in 83 percent of the patients. When 7 failures with patients taking ADR were switched to BCG and the disease cleared, the rate of complete remission for BCG rose to 85 percent. The recurrence rate per 100 patient-months was only slightly different for BCG (0.9) and ADR (0.8). The percentage of progressions continued to be higher for BCG (8%) than for ADR (5%). Cystectomies were performed in 2.5 percent of the BCG patients. Using the Cox regression model with covariates, we found drug treatment, tumor grade, and sex to be statistically significant in determining failures throughout the protocol. Although both BCG and ADR were effective over the course of the study, BCG is the drug of choice for residual tumor (Stages T1 and Tis).

Administration, Intravesical↗

PubMed1989

Liposomes prepared dynamically by interactions between bile salt and phospholipid molecules.

Quasi-elastic light scattering (QELS) studies showed that vesicles can spontaneously form from sodium glycocholate-egg phosphatidylcholine mixed micelles upon dilution with physiological saline buffer (pH 7.5). A water-soluble drug, cytosine arabinoside, did not affect the transition pattern. Transitions were also obtained when dilutions were performed using diluted serum solutions (5% and 10% serum in buffer). However, if intermicellar bile salt monomer concentration (imc) was kept constant in diluent media, the transition was completely suppressed. Approximately 10% of the cytosine arabinoside was trapped inside vesicles which were formed in buffer, although this value decreased to approx. 2.5% when diluted serum was used. These results suggest that the mixed micelle to vesicle transition can be an alternative means to sonication in loading drugs into in vitro vesicles. A good correlation was found between the transmission electron microscopy (TEM) diameter and the mean hydrodynamic diameter obtained by QELS.

Bile Acids and Salts↗

PubMed1988

The mechanical role of the trunk and lower extremities in a seated weight-moving task in the sagittal plane.

A two-dimensional, sagittally-symmetric biomechanical model was developed to analyze the joint moments required to stabilize the trunk in a seated, dynamic, weight-moving task. Kinematic and reaction force data were measured while subjects moved a hand-held weight (0-4 kgf) at shoulder level to and fro at 1 Hz. These data were then used for model input and validation purposes. A second, simpler model was used to simulate how joint loads varied with weight held, trunk inclination, and movement frequency. The results for this seated task demonstrate a) significant trunk, hip, knee, and ankle joint moments (37, 13, 4, 13 percent of maximum strength values, respectively) were required, b) considerable intersubject differences in mean joint moments (more than 66 percent) were found, which primarily were due to subtle differences in body segment kinematics and lower extremities use, and c) the important role of the lower extremities in stabilizing the trunk in the seated posture.

Adult↗

PubMed1982

Depressed natural killer cell activity in patients with hepatocellular carcinoma. In vitro effects of interferon and levamisole.

Enriched lymphocytes from patients with primary hepatocellular carcinoma showed considerably reduced natural cytotoxicity against two established hepatoma cell lines and against the myelogenous derived cell line K562, as compared to lymphocytes from normal volunteers or from patients with various nonmalignant liver diseases. The serum of hepatoma patients did not effect normal or patient NK cell activity. When lymphocytes from patients or controls were treated for three hours with human leukocyte interferon, NK cell cell activity was significantly improved. Levamisole did not produce a significant increase in normal NK cytotoxicity but did improve the killing of lymphocytes from patients with hepatocellular carcinoma.

Adult↗

PubMedDate not supplied

Efficient lipofection with cisplatin-resistant human tumor cells.

Seven of seven different cisplatin-resistant human tumor cell lines showed elevated lipofection activity as compared with their sensitive parent cells, although the degree of enhancement was not quantitatively correlated with the degree of cisplatin resistance. Enhanced transfection was seen by using the same reporter gene driven by three different promoter/enhancer sequencer or by using different reporter genes driven by the same promoter/enhancer. Cells resistant to actinomycin D, bleomycin, and nitrogen mustards were not more transfectable than the sensitive parent cells. Although the mechanism of enhanced transfection in cisplatin-resistant cells is not known, data indicated that enhanced transcription, multidrug-resistant phenotype, and methallothionein overexpression do not play a role.

Chloramphenicol O-Acetyltransferase↗

PubMedDate not supplied

Physical stability of teniposide in bile salt-egg phosphatidylcholine mixed micelles and liposomes.

Teniposide-containing bile salt-egg PC mixed micelles and their liposomes formed from dilution were investigated and compared for (i) their teniposide contents as a function of bile salt species, drug dose, the egg PC/BS molar ratio, total lipid concentration, ionic strength and storage states (freeze-thawed and freeze-dried state, and the presence of light and oxygen) and (ii) their mean particle size, stored under different conditions. The physical stability of teniposide in micelles and their liposomes increased with increasing hydrophobicity of bile salt the order being deoxycholate > cholate > conjugated cholate at all temperatures (10 degrees C, 23 degrees C, and 45 degrees C) studied. Teniposide-micelles were more stable at lower egg PC/BS molar ratios, while teniposide-liposomes were more stable at higher ratios. Teniposide stability slightly increased at higher total lipid concentration, indicating that bile salt-egg PC mixed micellar systems were in dynamic states. The presence of neither light nor oxygen significantly affected the stability of teniposide over the time and temperature range studied. However, the presence of salt in micellar and liposomal solutions greatly reduced teniposide loss by precipitation. Freezing or freeze-drying of teniposide-micelles induced neither micellar aggregation nor drug leakage. The stabilization may be due to the presence of detergent-like bile salts in the system.

Antineoplastic Agents, Phytogenic↗

PubMedDate not supplied

Stabilization of teniposide in aqueous mixtures of detergent-phospholipid.

Teniposide-containing mixed micelles and liposomes consisting of detergent and phospholipid were investigated and compared for their teniposide latency as functions of the mixed micellar preparation method, stabilizers, type of detergent,lipid composition and serum proteins after storage at 10 degrees C, and 23 degrees C, and 45 degrees C or/and freezing and freeze-drying. There was no significant difference in teniposide loss from liposomes obtained using different micellar preparation methods. Sugars, dextrose or sorbitol, had no effect on teniposide loss from liposome but stabilized teniposide micelles. Glutamic acid had no effect on teniposide loss from micelles but increased the loss from liposomes. The presence of cholesterol in bile salt-egg PC micelles had little effect on teniposide loss at 10 degrees C but generally increased it at 23 degrees C, and 45 degrees C, while bile salt-egg PC-cholesterol (9:9:1) liposomes were more stable than bile salt-egg PC liposomes. In contrast, teniposide loss from bile salt-egg PC-egg PE (2:1:1) liposomes or bile salt-egg PC-egg PA (16:15:1) micelles and liposomes increased remarkably, probably due to the surface charge and/or the destabilization of PC bilayer. However, bile salt-egg PC-soy PC (2:1:1) micelles and liposomes lost less amounts of teniposide under the same storage conditions. Further, the stability of teniposide was greatly increased by neutral detergents (e.g., CHAPS or octylglucoside). The loss of teniposide from CHAPS- or octylglucoside-egg PC micelles and liposomes after six months' storage at the ambient temperature were approximately 16% and 10%, respectively. Teniposide-micelles and liposomes, prepared in the presence of serum or serum protein, were more stable than CHAPS- or octylglucoside-egg PC liposomes. Teniposide was physically stable for at least 12 months when micelles were stored as the frozen or freeze-dried state. This result suggested that long-term storage for teniposide in neutral detergent-egg PC-soy PC micelles may be feasible in the presence of serum proteins.

Carbohydrates↗

PubMedDate not supplied

Cisplatin-based interferon gamma gene therapy of murine ovarian carcinoma.

Cis-diamminedichloroplatinum(II) increased in vivo lipofection efficiency of tumor cells with a target gene, interferon gamma (IFN gamma), in a murine metastatic ovarian carcinoma model. The expression of IFN gamma gene in ascitic tumors reached a peak at day 11 after cisplatin treatment and lasted over 1 week. A local increase in IFN gamma gene expression increased a local expression of inducible nitric oxide synthase (iNOS) and the tumor necrosis factor a gene. This treatment suppressed tumor growth (or killed tumor cells) and increased the long-term survival of animals (at least 80 days) without tumors, which was prevented by simultaneous treatment of iNOS inhibitor aminoguanidine. The results indicate that cisplatin-based IFN gamma gene therapy is an effective treatment protocol and nitric oxide may play a major part for tumor cell killing or growth.

Animals↗