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Biomedical subjects

G Zheng

Publications and source records attributed to G Zheng.

125 records · Page 7Linked to original sources
PubMed1992

[Regional vascular occlusion at hepatic hila for the resection of hepatic tumor--report of 63 cases].

A new operative procedure for hepatic segmentectomy was performed by dissecting the hepatic hila to occlude blood vessels to and from hemihepatis, one lobe or one segment which bore hepatoma. Forty-three liver cancers with 33 of them in stage IV, 4 metastatic liver cancers and 16 hemangiomas were resected by this method. The types of hepatic segmentectomy consisted of monosegmentectomy, multisegmentectomy, peripheral and central segmentectomy, segmentectomy after hepatic arteria embolization and resegmentectomy for recurrent hepatic cellular carcinoma etc. The vascular occlusion lasted as long as 120 minutes for the right portal vein and 70 minutes for the left. Intravenous infusion of extract from Salive mliltiorrhiza before vascular occlusion could prevent hepatic cells from reperfusion injury. The mentioned maneuvers resulted in mild postoperative liver dysfunction, rapid recovery and hepatocytes regeneration. Two patients died within 30 days postoperatively, constituting an operative mortality of 3.1%.

Adolescent↗
PubMed1992

Metabolic regulation of pigment formation of Onosma paniculatum cultured cells.

The pigment yields of Onosma paniculatum callus and suspension cultured cells were increased 5.5 and 8.1 fold of that of the control respectively, when 10(-5) M of copper ion was added into the medium. The pigments synthesis was also stimulated greatly when 10(-5) M of L-phenylalanine was added into the medium and the cells were cultured for twenty-one days. The maximum yield of pigments was obtained when 10(-6) M of ascorbic acid was added to the medium.

Ascorbic Acid↗
PubMed1991

[The effect of plaque fluid on demineralization of enamel powder].

The aim of this study was to explore any substance in dental plaque which might affect the demineralization of enamel. Plaque fluid was prepared by centrifugation of pooled plaque from 56 young adults without periodontal diseases. Enamel was separated from healthy teeth of adolescents and crushed into powder. The enamel powder was treated separately by plaque fluid and synthetic plaque fluid (as a control, with similar calcium, fluoride content and pH as the natural). After this, the enamel powder was washed with PBS. Both the plaque fluid-treated and synthetic plaque fluid-treated enamel powder were demineralized by mixed organic acid (pH 4.5). The calcium content in both plaque fluids, PBS and organic acid after treatment with enamel powder was analysed by atomic absorption spectrophotometer. The results showed that there was no promoting effect in plaque fluid on demineralization of enamel, but, on the other hand, some protecting action was observed which might contribute to the presence of proteins in plaque fluid.

Adult↗
PubMed1991

A study on the technology of mass cell culture of American ginseng (Panax quinquefolium L.).

The culture broth volume fitted for cell suspension culture of plants was 1/5 to 2/5 of shake flask capacity. The dissolved oxygen (DO) output of the detector increased with the increase of the temperature. The viscosity of American ginseng (Panax quinquefolium L.) cell cultures was obviously higher than that of the fresh medium. An appropriate agitation speed was 60 rpm for fermentation culture of American ginseng cells. When we increased osmotic pressure stress by the addition of mannitol to the nutrient medium in fermentation culture, the content of saponin of the cell cultures was increased greatly but the cell growth was inhibited. The study provides data for designing an appropriate fermentor to culture American ginseng cells on a large scale.

Cell Division↗
PubMed1990

[A new serotype of Salmonella IIIb].

An enterobacterium culture, S3188, providing with Salmonella biological characteristics, except exhibiting indole positive reaction, was isolated from the intestinal content of reptile a snake. It utilized malonate, did not ferment dulcitol, it attacked lactose promptly, and ONPG positive. H antigens appeared diphasic. By cross agglutination and absorption tests, it was demonstrated that the antigenic formula of this strain is 53:1, Z13:e, n,(Z15)... It was found to be a new serotype of Salmonella IIIb.

Animals↗
PubMed1989

Quantitative immunofluorescence assay for cyclobutyldithymidine dimers in individual mammalian cells.

An indirect immunofluorescence procedure was developed for the measurement of cyclobutyl dithymidine dimers in DNA of individual Syrian hamster embryo cells using a specific monoclonal antibody. A fluorescein-labeled secondary antibody and a fluorochrome which binds to DNA were used to measure the photoproduct and total DNA in the same nucleus. Fluorescence intensity was quantitated with a computer-assisted microfluorometric system which was calibrated with a uranyl oxide impregnated glass slide. Similar dose-response curves, i.e. normalized fluorescence intensity plotted as a function of dose of germicidal irradiation, were obtained with two different cell types. Normalized fluorescence intensity per nucleus was related to thymidine dimer content with a competitive enzyme-linked immunosorbent assay using DNA isolated from cells given doses of germicidal irradiation identical to those used in the immunofluorescence assay. Thymidine dimer levels produced by 10 J/m2 of germicidal irradiation (approximately 8 x 10(5)/nucleus) and which allow for 15-30% cell survival can readily be detected. The specific monoclonal antibody was labeled with tritium and used in the immunofluorescence assay to relate the number of antibodies bound to the number of thymidine dimers per cell. The data revealed that approximately 45% of the thymidine dimers in cells exposed to 100 J/m2 of germicidal irradiation and essentially all the T mean value of T in cells receiving 20 J/m2, were being detected in the indirect immunofluorescence assay. This technique can provide a sensitive means for measuring various types of DNA damage in individual cells given that the appropriate probes are available. It can be especially useful for monitoring occupationally or environmentally exposed populations where usually only small samples of cells or tissues are available.

Animals↗
PubMed1984

Computed tomographic scanning in rectal carcinoma.

Computed tomographic (CT) scanning has been used to assess the extent of local spread in 85 patients with rectal carcinoma. In 37 patients with carcinoma of the rectum who were scanned before surgery, good correlation was found between the extent of local invasion, as assessed by scanning, and that demonstrated at operation by histological assessment. Scanning is not a reliable method for assessing regional lymph node involvement. Forty-eight patients presented with recurrent rectal carcinoma after previous rectal excision (30 patients after abdominoperineal and 18 patients after anterior resection). CT scanning was shown to be a valuable tool in establishing the diagnosis of recurrent tumour. Most of these patients have spread which precludes further curative surgery. CT may identify those patients who have a resectable recurrence, but is especially valuable in planning radiotherapy which may be used for palliation.

Aged↗
PubMedDate not supplied

Comparative in vivo sensitizing efficacy of porphyrin and chlorin dimers joined with ester, ether, carbon-carbon or amide bonds.

The anti-cancer activity of dimers joined with ether, ester or carbon-carbon bonds by photodynamic therapy (PDT) was compared by using DBA/2 mice transplanted with SMT/F tumors. Dimers with ether and carbon-carbon linkages were found to be more effective than those linked with ester bonds. Variation of the substituents at peripheral positions made a significant difference in in vivo efficacy. Among the ether and carbon-carbon linked dimers, the divinyl analogs were found to be most effective. The preliminary in vivo results also suggest that the position(s) of the hydrophilic substituents in the molecules make a remarkable difference in photosensitizing activity. An unsymmetrical dimer with an amide linkage, obtained from 2-(1-hexyloxyethyl)-2-devinyl pyropheophorbide-a (HPPH) was found to be less effective than HPPH.

Amides↗
PubMedDate not supplied

New orthopaedic implant management tool for computer-assisted planning, navigation, and simulation: from implant CAD files to a standardized XML-based implant database.

Computer-Assisted Orthopaedic Surgery (CAOS) has made much progress over the last 10 years. Navigation systems have been recognized as important tools that help surgeons, and various such systems have been developed. A disadvantage of these systems is that they use non-standard formalisms and techniques. As a result, there are no standard concepts for implant and tool management or data formats to store information for use in 3D planning and navigation. We addressed these limitations and developed a practical and generic solution that offers benefits for surgeons, implant manufacturers, and CAS application developers. We developed a virtual implant database containing geometrical as well as calibration information for orthopedic implants and instruments, with a focus on trauma. This database has been successfully tested for various applications in the client/server mode. The implant information is not static, however, because manufacturers periodically revise their implants, resulting in the deletion of some implants and the introduction of new ones. Tracking these continuous changes and keeping CAS systems up to date is a tedious task if done manually. This leads to additional costs for system development, and some errors are inevitably generated due to the huge amount of information that has to be processed. To ease management with respect to implant life cycle, we developed a tool to assist end-users (surgeons, hospitals, CAS system providers, and implant manufacturers) in managing their implants. Our system can be used for pre-operative planning and intra-operative navigation, and also for any surgical simulation involving orthopedic implants. Currently, this tool allows addition of new implants, modification of existing ones, deletion of obsolete implants, export of a given implant, and also creation of backups. Our implant management system has been successfully tested in the laboratory with very promising results. It makes it possible to fill the current gap that exists between the CAS system and implant manufacturers, hospitals, and surgeons.

Computer-Aided Design↗
PubMedDate not supplied

Effects of green tea on growth, food utilization and lipid metabolism in mice.

To find whether green tea has anti-obesity effects in mice, female ICR mice were fed on diets containing 1, 2 and 4% green tea powder for 16 weeks and the body weight and food intake were weighed. After the administration of green tea, the ovaries, kidneys, adrenals, liver, spleen, brain, pituitary and intraperitoneal adipose tissues in the mice were weighed and lipid levels in the serum and in the liver and serum leptin levels were measured. It was found that body weight increase and intraperitoneal adipose tissues were remarkably suppressed by the administration of diets containing 2 and 4% green tea powder. Food intake was suppressed by feeding the 4% green tea diet. Concentrations of total cholesterol in the liver, triglycerides in serum and liver and nonestrified fatty acids in serum from mice which were administered green tea diet were lower than those in the controls. Leptin levels in serum showed a decrease with green tea treatments. These results indicated that lipid metabolism in mice was suppressed by the administration of green tea powder and thereby the fatty accumulation and body weight increase was suppressed.

Adipose Tissue↗