Biomedical subjects

T Mao

Publications and source records attributed to T Mao.

24 records · Page 2Linked to original sources

PubMed1997

Isolation and identification of berberine from cell cultures of Coptis chinensis.

Calli were formed by the young leaves of Coptis chinensis inoculated onto a 6,7-V solid medium containing 1.0-2.0 mg/L of 2,4-D and 0.1 mg/L of kinetin. The loose calli were chosen and transferred into a liquid medium and free cells and cell aggregates were obtained. Cell lines with a higher content of berberine were selected by irradiation of suspension culture and a plate-screening technique. After 35 subcultures, the selected cell lines were cultured in a larger quantity for the extraction of alkaloids. Yellow crystals were obtained from the extracts and identified as berberine by TCL, UV and IR absorption, and mass spectrography. They have the same molecular structure and anti-bacterium activities as the berberine obtained from natural plants.

Berberine↗

PubMed1995

[Relationship between elevated plasma endothelin-1 level and renal function in patients with diabetic nephropathy].

Plasma endothelin-1 (ET-1) level was measured with radioimmunoassay in 33 normal subjects and 92 patients with different stages of diabetic nephropathy, consisting of 35 cases of diabetes mellitus with normal urinary albumin excretion (DM), 22 cases of incipient diabetic nephropathy (IDN), 22 cases of overt diabetic nephropathy (ODN), 8 cases with azotemia (DNa) and 5 cases with uremia (DNu). The results showed that plasma ET-1 levels in DNa and DNu groups (30.24 +/- 1.93 ng/L and 36.38 +/- 3.62 ng/L respectively) were significantly higher than those in other groups (P < 0.05); ET-1 level in ODN group (20.50 +/- 0.93 ng/L) was significantly higher than those in DM and IDN groups (P < 0.001); ET-1 level in IDN group was also significantly higher than that in DM group (17.79 +/- 0.74 vs. 15.06 +/- 0.63 ng/L, P < 0.01); All the above values were significantly higher than that in normal subjects (7.08 +/- 0.22 ng/L) (P < 0.001). There was significant positive correlation between ET-1 level and HbA1c, systolic pressure, diastolic pressure, blood urea nitrogen, serum creatine, uAER and a significant negative correlation between ET-1 level and glomerular filtration rate. It is shown that progressive elevation of plasma ET-1 level is closely related with different stages of renal function impairment, suggesting strongly the role of ET-1 in the development and progression of diabetic nephropathy.

Diabetic Nephropathies↗

PubMed1992

[Clinical significance on expression of the ras gene product P21 in human cervical carcinoma tissues].

Using MAB-P21 as a probe, the expression of gene product was studied by immunohistochemical ABC method, ABC staining of gel electrophoresis and ELISA quantitative analysis. The expression of P21 was detected in 107 cases of uterine cervix tissues, among which 70 were cervical carcinoma, 30 were chronic cervicitis and 7 normal cervix. Experimental results showed that obviously positive expression was noted in the specimens of cervical carcinoma and its positive rate was 72.8% (51/70). It was observed that the expression of P21 varied with grades of cell differentiation in cervical carcinoma. The level of P21 expression in high differentiated type was higher than that of the middle and low differentiated types. On the contrary, there was no detectable ras P21 in the normal cervix tissue and only 2 cases of cervicitis expressed positively (2/30). The results of ABC staining of electrophoresis showed that there was a P21 special staining band in cervical carcinoma tissues. And the contents of P21 protein were higher in cervical carcinoma than in normal cervix and cervicitis (t test, P less than 0.001). The expression of P21 was considerably enhanced in malignant tissue as compared with that in benign lesion.

Adenocarcinoma↗

PubMed1991

[The status of human papillomavirus 16 DNA in the tissues of human esophagus carcinoma].

DNAs from 24 cases of human esophagus carcinoma and 24 cases of corresponding para-carcinoma tissues were detected by dot hybridization and Southern hybridization techniques using human papillomavirus (HPV) 16 type DNA as probe. The results indicated that the positive rate of the HPV 16 DNA hybridization was 50% (12/24) in esophagus carcinoma tissues, and 37% (9/24) in para-carcinoma tissues. The results of Southern hybridization showed obviously the positive hybridizing band in the zone of 7.2 kb in smear. It implied that HPV 16 DNA was possibly integrated into the tissue's DNA of esophagus carcinoma. In the fetal esophagus tissues as negative control, 3 cases out of 4 showed positive results. The significance has to be further investigated. This experiment has studied the status of HPV 16 type in the tissues of esophagus carcinoma and para-carcinoma at molecular level. This is just a study of the virus etiology of esophagus carcinoma.

Blotting, Southern↗

PubMed1989

[Study on molecular hybridization with biotin-labelled HPV 16 DNA probe in human cervical carcinoma].

Biotin-labelled human papillomavirus (HPV) 16 type DNA probe was prepared by the techniques of molecular biology. And dot hybridization technique was used to detect the HPV 16 homologous sequences in the tissues DNA of human cervical carcinoma. The results indicated that 16 cases out of 28 of the human cervical carcinoma tissues were positive. The positive rate was 57%. The other 4 cases of normal uterine cervix tissues were negative. Only 1 in 4 chronic cervicitis tissues showed positive. The HPV 16 plasmid DNA, as the positive control group, showed strong positive, while lambda-phage DNA was negative. The results have shown that the genome of the HPV actually exists in the tissue of the cervical carcinoma and that there is a close relationship between the cervical carcinoma and HPV infection. This experiment adopted the Biotin-labelled HPV 16 DNA probe. And it may provide us with a quick and sensitive method for investigation of the infection of HPV and its role in the carcinogenesis of cervical carcinoma.

Biotin↗

PubMed1989

[Studies on oncogene and its products of human nasopharyngeal carcinoma].

Oncogene of nasopharyngeal carcinoma (NPC) by means of external origin DNA transfection experiment and its gene products by immunohistochemical method have been studied. These DNAs were isolated from human primary poorly differentiated NPC tissues and were transfected into NIH/3T3 mouse fibroblasts to induce the foci of the morphologically transformed cells in the culture, while DNAs of normal placenta tissues failed to do so. The DNAs were extracted from the primary and secondary transformed cells to analyse human sequence with human Alu sequence probe. The human sequence has been detected in the DNAs of the primary and secondary transformed foci cells, while none of the human sequence was detected in the DNAs of the control. The results indicated that human transforming sequences had been integrated into transformed cells. The malignant properties of the transformed foci cells were evidenced by tumorigenic experiment of nude mice. The transformed foci cells were inoculated subcutaneously in the nude mice and induced fibrosarcoma in vivo. The tumorigenic rate was 87.5%. It was further demonstrated that DNAs from human NPC possessed carcinogenicity and induced malignant transformation. The primary result revealed that the transforming gene of NPC may be homologue to Ha-ras oncogene. The expression of Ha-ras gene products-p21 has been studied in human NPC tissues. The primary results showed a positive expression of p21 in human NPC tissues by immunohistochemical method. The positive rate was 90.4%.

Animals↗