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Biomedical subjects

X L Li

Publications and source records attributed to X L Li.

At least 145 records · Page 8Linked to original sources
PubMed1989

[Isolation and fermentation conditions of polyvinyl alcohol-degrading enzyme producing strain].

A bacterium D8 strain which high efficiently degrading PVA was isolated from waste water of factory. The strain possesses the abilities of completely degrading 0.5 per cent of PVA (500, 1700) included in the culture medium for four days. It was identified Pseudomonas pseudoalcaligenes. Fermentation conditions of the strain have been investigated. The suitable medium consisted of PVA 1.5% (NH4)2SO40.1%, K2HPO4 0.24%, KH2PO4 0.04%, MgSO4.7H2O 0.035%, NaCl 0.01%, FeSO4 0.001%, yeast extract 0.15%, pH 7.5. The optimal condition for enzyme production are as follows: 250 ml shake filled with 30 ml medium, 30 degrees C, 160n/min incubation period 72 h. Under such conditions enzyme activity is highest.

Alcohol Oxidoreductases↗
PubMed1988

Establishment and biological properties of mouse granulocytic leukemic cell line-L833.

A granulocytic leukemic cell line, called L833 has been established through culturing in vitro from mouse bone marrow of transplantable granulocytic leukemia. More than 280 passages have been performed in 3 years. Cell growth has been rapid and stable. Incidence of tumour formation was 100% with various routes of inoculation. The nature of granulocytic leukemia was confirmed by examination of cytology, cytochemistry, pathology and ultrastructural changes. Analysis proved chromosomes to be hypodiploid with model number of 39, loss of chromosomes, and presence of a marker. Besides the chromosomal change as mentioned above, both L883-A and L833-B derived from colonies formed from the L833 cells cultured in semi-solid agar medium, have their own marker. The cell line was sensitive to various types of antitumour agents in varying degrees. It was also sensitive to ionizing radiation. D0 values of L833 and L883-A cells were 98.8 and 104.9 rad, respectively. The results were similar to that of L801. Establishment of this cell line is of important significance for studying leukemia and screening anti-tumour agents, as well as provides a useful direct, economic and precisely quantitative tool for other relative studies.

Animals↗
PubMed1987

[Brenner tumor of the ovary--a clinicopathological report of 5 cases].

This paper reports 5 cases of Brenner tumor of the ovary treated in our hospital from 1967 to 1985. The patients' mean age was 54.6 years. Three lesions were solid, 1 cystic and the other occurred on the wall of a borderline malignant mucinous cystadenoma. All the 5 cases were benign by pathology. The clinical symptoms were abdominal pain in 3 cases, 2 of which had a torsion of the tumor pedicle, abdominal mass in 1 and abdominal swelling in the other. All the cases possessed the same feature that the tumor was composed of both hyperplastic epithelial nest and fibrous stroma. In histology, there were 3 transitional epithelial cell types and 2 basal cell-like types. Histogenesis of the Brenner tumor, according to the authors' observation, was shown by: 1. The epithelial cell nests of Brenner tumor were similar to the transitional epithelium of the urinary tract in 60% of these cases; basal-like cell in the early stage of differentiation comprised 40%, 2. In 80% of patients, there was observed, in the cell nuclei, a longitudinal groove, which resembled the cells of Walthard cell nests; 3. The transitional epithelial cells were found in the cyst wall of 1 polycystic tumor; another case was complicated with mucinous cystadenoma and there was no sharp demarcation between the two tumors under microscope. It suggests that the histogenesis imply that the Brenner tumor may arise from the coelomic epithelium of para-mesonephros. The authors also believe that certain Brenner tumors have endocrine activity, but the relation between which and the tumor stroma luteinization should be further studied.

Adult↗
PubMed1987

[Chemoprevention of cancer of the uterine cervix--preliminary study on the intervention of the cervical precancerous lesion by retinamide RII].

Twenty seven women with mild, moderate or severe cervical dysplasia proven by pathology were treated by retinamide RII suppository. Retinamide RII suppository, 10 mg QD, was given intravaginally for six months (three months as a course). Clinical examination, Papanicolaou cytology and tissue biopsy under colposcope were carried out before and after treatment. The results indicated that after the second course, 26 out of 27 patients responded; of them, precancerous lesions disappeared in 24 and even normal squamous epithelium was observed in 3. The overall response rate was 96.29% and the marked response rate was 88.89%. The general side effects were mild. There was little cervical and vaginal irritation which was well tolerated. The results of this clinical trial make available a practical base for chemoprevention of cervical cancer.

Antineoplastic Agents↗
PubMed1987

[In vitro studies of the cell cycle of mouse myelomonocytic leukemia using a fluorescence activated cell sorter and autoradiography].

Cell cycle and various phase time of mouse myelomonocytic leukemia cells were studied in vitro with Fluorescence Activated Cell Sorter (FACS 420, Becton-Dikinson FACS Systems, Sunnyvale, CA, USA) in testing cellular DNA content and with autoradiography. At the same time, doubling time was calculated by counting the number of cells cultured in vitro within 6 days following implantation. According to the cellular DNA content, the proportions of various cell phases in the whole cell population were as follows: G1, S and G2 plus M phases take up 30.5%, 47.9% and 21.6%. Basing on autoradiography and direct counting, the cell number, the cell cycle, duration of various cell phases and doubling time were as follows: LI = 98.0%, MI = 1.7 +/- 0.9%, TG1 = 4.9 hrs, TS = 8.0 hrs, TG2 = 2.8 hrs, Tm = 0.3 hr, TC = 16.0 hrs, TD = 17.0 hrs. FACS assay showed that the duration of various cell phases are quite similar to that calculated by autoradiography. Therefore a simple and rapid FACS method may be widely used in the studies of cell cycle instead of autoradiography if estimating computer program is available.

Animals↗
PubMed1986

Transforming activity of human nasopharyngeal carcinoma DNA.

NIH 3T3 cells were transfected with the DNAs from biopsy specimens of human nasopharyngeal carcinoma (NPC, EBV DNA positive) using calcium phosphate precipitation method. The malignant, transformed foci of NIH 3T3 cells have been observed and cloned. The hybridization of transfectant DNA digested by EcoRI with total human leukocyte DNA as probe was performed. The strong signal of smear comparing with NIH 3T3 DNA as control was observed. It was implied that the putative human transforming sequences had been integrated into transformed cells. Employing soft agar culture, the transformed cells can grow and form cell colonies. Following transfer, the foci were able to grow and adhere to a glass wall. These cells were easily agglutinated by con A. The cloned foci have been inoculated into nude mice with the formation of highly malignant sarcomas. In preliminary experiments for characterizing the transforming sequences, Ha-ras and Blym 1 were found in transfectants derived from one of the NPC DNA samples. It is implicated that these two oncogenes might be responsible for the acquisition of malignant phenotypic character of some human NPC. The further identification of oncogenes in NPC is currently in progress.

Animals↗
PubMed1986

Expression of N-ras gene in human primary hepatocarcinoma.

Poly(A)+ RNA was isolated from 9 specimens of human primary hepatic carcinoma, 1 non-tumorous liver tissue adjacent to cancer and 1 normal liver tissue samples. The Oligo-dT cellulose-purified poly(A)+ RNAs were subjected to formaldehyde agarose gel electrophoresis, Northern transfer and hybridization with various oncogene probes. Two RNA species, 5.6 kb and 2.2 kb were identified by N-ras gene hybridization in 6 out of 9 mRNA samples from primary hepatic carcinoma specimen. N-ras specific mRNA was not detectable in mRNA samples from normal human liver and tumor surrounding cirrhotic tissue. No detectable hybridization of mRNA from hepatoma and normal liver with Ki-ras or Ha-ras was observed. As human N-ras gene has been identified in DNA of mouse transfectants transformed with PHC DNA, it strongly suggests that N-ras gene might be responsible for the transforming activity of part of cases of human liver cancer.

Carcinoma, Hepatocellular↗