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Biomedical subjects

L F Cheng

Publications and source records attributed to L F Cheng.

13 recordsLinked to original sources
PubMed2003

Photocatalytic oxidation using a new catalyst--TiO2 microsphere--for water and wastewater treatment.

Since the suspended TiO2 powder enjoys free contact with UV irradiation in a photoreactor system, it can generally achieve better efficiency than the immobilized TiO2 catalysts. However, the separation and reuse of this catalyst powder from treated water often limit its application in practice. In this study, a new type of TiO2 catalyst called TiO2 microsphere was prepared by a sol-spraying-calcination method, which can easily settle in its aqueous suspensions under gravity. The SEM image of the TiO2 microsphere samples demonstrated that they had an almost spherical shape with a particle size of 30-160 microm, while the XRD analysis indicated that these TiO2 microspheres still had a crystal size of 8.1 nm. Since these TiO2 microspheres had a porous structure with higher specific surface area and pore volume than normal TiO2 powders, they appeared to have strong adsorption ability in its aqueous suspensions. The photocatalytic activity of the TiO2 microspheres was evaluated in the photodegradations of salicylic acid (SA) and sulfosalicylic acid (SSA). The experimental results showed that the reaction rate using the TiO2 microspheres was similar to that using the TiO2 powders in the SA suspensions and even higher than that in the SSA suspensions. Chemical and physical properties of the TiO2 microspheres and powders that are attributed to photoactivity were discussed based on the Langmuir-Hinshelwood kinetic model. The prepared TiO2 microsphere samples were reused in the photooxidation reaction more than 50 times. It was found that there was no significant weakening in their photoactivity and no change in their particle shape. This TiO2 microsphere catalyst can be simply used to conduct an effective photooxidation in its suspension for water and wastewater treatment with ease of recovery from treated water.

Catalysis↗
PubMed1998

Distraction osteogenesis in the hand.

Distraction osteogenesis was used to correct congenital hand deformities in 12 digits. The patients' ages at the time of distraction ranged between 2.5 and 7 years. A total of nine patients underwent lengthening of 12 bones. The average period of distraction was 31.1 +/- 17.6 days. The average length of distraction was 23.6 +/- 7.3 mm. Seventeen percent of the patients after lengthening had an angular deformity that required remodeling of the regenerate. No infections were noted. Distraction osteogenesis provides a useful tool for reliable and predictable correction of osseous defects with vascular bone in patients with congenital anomalies of the hand.

Acrocephalosyndactylia↗
PubMed1996

Central-type eight-toed polydactyly associated with ipsilateral complex renogluteal agenesis: a case report with 8 years' follow-up.

At birth, a baby girl was found to have central-type eight-toed polydactyly of the left foot associated with ipsilateral nonvisualization of the kidney and atrophy of the gluteal maximum muscle. X-ray examination showed eight completely developed metatarsal and digit bones, and a chromosome study showed a normal 46, XX karyotype. She received ray amputation of the extra toes when she was 1 year old. Follow-up examination at age 9 showed unchanged renogluteal anomalies and a slightly smaller left foot. In addition, a bony defect over the posterior iliac spine and a wide femoral neck-shaft angle were found on the radiograph. Her left leg was found to be 1 cm shorter than the right, but there was no evidence of valgus or varus. Presently she can walk and run quite well, and there is no callus formation over her sole. The timing and options for excision of the supernumerary digits are discussed and this rare disease reviewed.

Abnormalities, Multiple↗
PubMed1995

Human keratinocyte culture using porcine pituitary extract in serum-free medium.

Extensive burn wound coverage remains a major problem in acute and reconstructive stages due to shortage of autologous skin donor sites. Many reports have described successful coverage of extensive burn wounds by using cultured keratinocytes sheet graft alone or overlaying a glycosaminoglycan substrate, allodermis or xenodermis. In our experience, the use of Boyce and Ham's serum-free medium made the preparation of keratinocyte cultures simple and the cell growth was prompt. In this study, one of the supplements in Boyce's culture medium, the bovine pituitary extract (BPE at concentration of 140 micrograms/ml), was replaced by different concentrations of fresh frozen porcine pituitary extract (PPE). The protein concentration of the original preparation of PPE was also 140 micrograms/ml but in which 375 +/- 21 pg/ml (1/10 dilution) of platelet-derived growth factor (PDGF) was detected by immunoassay (PDGF ELISA). Our results proved that PPE is an ideal supplement for the in vitro growth of keratinocytes, and when its protein concentration is 350 micrograms/ml will induce a significant keratinocyte growth by day 9 when compared to the regular BPE and also to the other concentrations of PPE (P < 0.05).

Animals↗
PubMed1994

[Primary hepatic carcinoma treated by chemoembolization--a clinical analysis of 20 cases with survival period longer than 3 years].

Advanced primary hepatic carcinoma was treated in 110 patients by percutaneous transhepatic arterial chemoembolization (TAE) from January 1987 to October 1989 according to Seldinger's protocol with mitomycin C, Adriamycin or carboplatin and 40% iodized oil. The treatment was given once every 4-12 weeks and the number of treatment for each patient varied from 2 to 19 depending on patients' condition and response. Of the 110 patients, 20 survived > 3 years, among which 7 survived > 4 years and 4 survived > 5 years. Following treatment, a greater than 50% reduction of tumor size was observed in 13 cases and a decrease in AFP to normal level in 12 cases. Seven patients were treated with TAE followed by tumor resection and, 2 patients were treated with TAE due to recurrence after tumor resection 11 patients were treated with TAE alone. The mean survival period was 53.1 and 43.5 months, respectively. TAE is considered as the first choice of palliative treatment for patients with advanced hepatic carcinoma. Factors that might influence the result of TAE treatment are discussed.

Adult↗
PubMed1992

[Sclerotherapy of gastric varices].

160 patients, 128 males, 32 females, with portal hypertension were admitted into our department for sclerotherapy from May 1987 to August 1990. Gastric fundus could be observed clearly in 145 of these patients who were examined with endoscope. Gastric varices were found in 105 of the 145 patients. Sclerotherapy of gastric varices were carried out in 47 of the 105 patients by intravenous injection with the method of lesser injection points and larger dosage. The results showed that a satisfactory effect was obtained with a rate of immediate stoppage of bleeding by 95.7%; and a rate of disappearance of gastric varices by 95.3%. The rate of recurrent bleeding was 7.9%. In addition, the occurrence rate, the severity, the manifestations under endoscopy and the classification of gastric varices as well as the indication, and complications of sclerotherapy of gastric varices were discussed in detail.

Adolescent↗
PubMed1989

Tumoricidal effect of controlled-release polymeric needle devices containing adriamycin HCl in tumor-bearing mice.

Controlled-release polymeric needle devices containing adriamycin HCL (ADH) were investigated by an in vitro dissolution study in normal saline solution and an in vivo antitumor activity in C3H mice bearing mammary carcinoma and nude mice bearing brain tumor. HPMC was used as a release rate regulator. The ADH released from needle devices was controlled by the types of polymer used and the addition of HPMC. EVA needle devices exhibit a zero order release behavior better than that of PLA needle devices. Tumor growth was markedly inhibited by treatment with needle devices after locally inserted into the solid tumor. The rank of antitumor activity of the needle devices is EVA greater than PLA greater than EVA-HPMC greater than PLA-HPMC. No significant changes in body weight of mice after treatment were found in treated groups as compared to controlled groups. The preliminary results of our study suggest that needle device dosage form shows a controlled release behavior and may be applicable as a drug carrier for delivery of antitumor drug in cancer chemotherapy.

Animals↗
PubMed1988

Controlled release of adriamycin HCl from polymeric needle devices.

Two types of polymeric needle devices (reservoir type and matrix type) were prepared. The release behavior and mechanism of adriamycin HCl from these needle devices were investigated and deduced. Adriamycin HCl released from reservoir type needle devices exhibited a zero order release kinetic, but a Higuchi membrane-diffusion controlled model was shown in matrix type needle devices. A lag time and burst effect were obtained in reservoir type and matrix needle devices, respectively. The release of adriamycin HCl from these needle devices was controlled and can be monitored by adding a hydrophilic or hydrophobic additive.

Biocompatible Materials↗
PubMed1986

Exocytosis in rat parotid acini after in vitro treatment with forskolin is accompanied by cellular redistribution of regulatory subunits of cyclic AMP-dependent protein kinase.

Incubation of rat parotid acinar tissue with 1 mumol/L forskolin resulted in progressive exocytosis which was virtually complete after a 30-minute incubation period. Cyclic AMP binding to protein kinase (cA-PK) regulatory (R) subunits, determined by photo-affinity labeling with [32P]-8-azido cyclic AMP, was found to increase in a time-dependent manner in the 10,000-g supernatant fraction of a broken cell preparation. An apparent redistribution of protein kinase R subunits took place in the 600-g supernatant after in vitro treatment of cells with forskolin. In control cells, RI and RII subunits and a 35-to-40-kdal fragment were present in approximately equal amounts throughout the incubation. Azido labeling of RII appeared either to increase or to remain unchanged, while that of RI decreased in the 600-g pellet. Only type I isozyme R subunits were found in the 600-g pellet in either the absence or presence of forskolin. These finding indicate that a temporal relationship exists between stimulated protein exocytosis and cyclic AMP-dependent protein kinase activation. Forskolin stimulation of adenylate cyclase in salivary gland cells therefore provides a defined system for the study of cyclic AMP-mediated protein secretion.

Animals↗
PubMed1983

An unusual autoimmune hemolytic anemia in a patient with immunoblastic sarcoma.

This report describes a patient with immunoblastic sarcoma and autoimmune hemolytic anemia with reticulocytopenia and red cell hypoplasia. Both IgG and IgM red cell autoantibodies were present in the patient's serum, and both antibodies had the uncommon specificity of anti-IT. This report appears to be the first to describe IgG auto anti-IT and autoimmune hemolytic anemia in a patient who did not have Hodgkin's disease; the laboratory findings and clinical course are described. The reticulocytopenia and red cell hypoplasia may have been immunologically mediated. The patient responded to plasma exchange, corticosteroids, and chemotherapy.

Anemia, Hemolytic, Autoimmune↗
PubMedDate not supplied

Expression of multidrug resistance-related markers in gastric cancer.

BACKGROUND: To detect the expression of glutathione S-transferase Pi(GST-pi), multidrug resistance-associated protein (MRP), lung-resistance protein(LRP), multidrug resistance gene1 (MDR1) and MGr1 antigen(MGr1-Ag) in the patients with primary gastric cancer and without any prior chemotherapy and to evaluate the correlations between them. PATIENTS AND METHODS: The expression of GST-pi, MRP, LRP and MDR1 in cancer tissue and the adjacent non-cancerous tissue from 50 patients was examined by semiquantitative reverse transcription-polymerase chain reaction (RT-PCR). The expression of MGr1-Ag in these tissues was also examined by immunohistochemistry. RESULTS: The positive rate of GST-pi mRNA, MRP mRNA, LRP mRNA, MDR1mRNA and MGr1-Ag in gastric cancer tissue was 36.00%, 12.00%, 10.00%, 10.00% and 18.00% respectively. The overall positive rate of their expression was 58.00%. Clinicopathological factors were not significantly related to their expression. No significant correlation was observed between these markers. CONCLUSION: These MDR markers are differently over-expressed and no coexpression exists in gastric cancer. MGr1-Ag was a novel MDR protein.

ATP Binding Cassette Transporter, Subfamily B, Mem↗