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Biomedical subjects

S Cao

Publications and source records attributed to S Cao.

At least 109 records · Page 6Linked to original sources
PubMed1993

Calculating potential doubling time using monoclonal antibodies specific for two halogenated thymidine analogues.

PURPOSE: A new flow cytometric technique that allows for two-incorporated thymidine analogues to be measured simultaneously and independently has been used to improve the accuracy of in vivo cell kinetic estimates, i.e., the length of S-phase (TS) and potential doubling time (Tpot). METHODS AND MATERIALS: The analogues chlorodeoxyuridine and iododeoxyuridine were injected at different times into mice bearing the mouse mammary tumor MCaK. At different times after labeling, the tumors were harvested and prepared for three color flow cytometric analysis of DNA, chlorodeoxyuridine, and iododeoxyuridine. Control experiments showed that similar estimates of Tpot were obtained from each label when administered singly, or as staggered pulses. Comparisons were made between TS and Tpot calculated from a single label (single point), from the averaged result of the two labels from the same tumor (two point-ave), and from the simultaneous nonlinear fitting of the measured parameters from the two labels, from the same tumor (two point-fit). These estimates of TS and Tpot were then compared to reference values obtained by fitting the pooled measured parameters from all the tumors, that were labeled for different periods of time. RESULTS: While all of the methods resulted in similar mean estimates of TS and Tpot that were close to the reference values, the fewest assumptions, and the least variability in the results, were obtained using the two point-fit data. CONCLUSION: The estimation of Tpot using two thymidine analogues is more accurate than that obtained from a single label.

Animals↗
PubMed1993

Effect of caloric restriction on aflatoxin B1-induced DNA synthesis, AFB1-DNA binding and cell proliferation in Fischer 344 rats.

Young adult male Fischer rats maintained on a reduced calorie diet (60% of ad libitum food consumption) for 6 weeks showed a decrease in the binding of aflatoxin B1 (AFB1) to hepatic or renal nuclear DNA and a reduction of AFB1-induced hepatocellular damage. Repeated dosing of rats with AFB1 resulted in the inhibition of hepatic and renal DNA synthesis measured by [3H]thymidine incorporation. However, the rate of DNA synthesis was greater in ad libitum (AL) rats than in calorically restricted (CR) animals. Three days after AFB1 dosing, the rate of DNA synthesis had recovered to the control level. Cell cycle analyses measured by a flow cytometric method on kidney cells of both AL and CR rats showed that there were no significant changes in cell populations in the S phase between these two groups of rats. AFB1 inhibited the cell proliferation on an average of 33%. The restoration of the cell proliferation in kidney cells was found on the third day after AFB1 dosing. The rate of the regenerative cell proliferation was found to be slightly greater in AL rats than in CR animals. The AFB1-induced regenerative DNA synthesis in both liver and kidney was retarded by CR.

Aflatoxin B1↗
PubMed1993

[Optimum sample size in the crossing experiments].

Crossing experiments are time-consuming and costly, hence, it is very essential to make a through plan and provide the necessary and sufficient sample size in advance. The common formula of the sample size in statistics is not suitable for the crossing experiments. This paper discussed two cases and put forward a corresponding estimate formula of sample size for crossing experiments, by utilizing the sample size derived from the estimate formula to arrange the crossing experiments; thus the total experimentation cost could be reduced to the lowest, or the total number of tested livestocks may be the fewest under the precondition of satisfying the requirements of the experiment designer.

Costs and Cost Analysis↗
PubMed1992

Overexpression of the c-erbB-2/neu-encoded p185 protein in primary lung cancer.

The c-erbB-2/neu gene encodes a transmembrane protein of 185 kDa (p185) with tyrosine kinase activity and extensive sequence homology to epidermal growth factor receptor. Amplification and overexpression of the c-erbB-2/neu gene has been shown in certain human tumors and is postulated to be important in human carcinogenesis. High levels of expression of the c-erbB-2/neu gene have been reported in non-small-cell lung cancer (NSCLC) cell lines and primary tumors from the United States. Since geographical and cultural factors may contribute to the development of certain types of cancer, we examined p185 examined p185 expression in 120 tumors from Chinese patients with lung cancers of different cell types and used immunohistochemical staining to determine the extent and general significance of p185 expression in human primary lung cancer. Our results demonstrate that 58.8% of the NSCLCs expressed p185 and that expression of p185 was observed only in NSCLC and not in small-cell lung cancers. Thirty-three of 41 adenocarcinomas and 24 of 55 squamous cell carcinomas among the NSCLCs examined were found to express p185 at levels different from those of normal lung. For the squamous cell carcinomas, p185 expression was correlated with lymph node metastasis (P less than 0.01), but for the adenocarcinomas, it was not (P greater than 0.05). In addition, expression of p185 in NSCLC was significantly more frequent in patients in advanced clinical stages. Our findings indicate that p185 expression is a frequent event and a general phenomenon in NSCLC and is correlated with poor clinical prognostic indicators, suggesting that expression of p185 may be of potential prognostic importance in NSCLC.

Adenocarcinoma↗
PubMed1992

[Saponins in the fruit pedicels of Panax notoginseng (Burk.) F.H. Chen (continue)].

Six saponins were isolated from the fruit pedicels of Panax notoginseng. Five of them were identified as gypenoside-XVII, -XV, ginsenoside-Rb1, and notoginsenoside-Fc, -Fa on the basis of chemical methods, spectroscopic analysis and comparison with authentic standards. Quantitative determination of the major saponins in fruit pedicels from the plant was made by thin layer chromatography-densitometry.

Drugs, Chinese Herbal↗
PubMed1992

Clinical significance of flow cytometric deoxyribonucleic acid measurements of deparaffinized specimens in bladder tumors.

A retrospective study of flow cytometric measurements on paraffin-embedded tumor specimens from 188 patients with bladder tumor was conducted. Results were analyzed in combination with the morphological variation in bladder tumors. It was found that the deoxyribonucleic acid (DNA) ploidy pattern, the degree of infiltration and the multiplicity of bladder tumor were closely related with tumor recurrence, among which the DNA ploidy pattern was most significant. In aneuploid bladder tumors, the recurrence rate and the mean annual recurrence frequency were 76.7% and 1.46, respectively, and in the diploid bladder tumors, they were 18.7% and 0.33, respectively. Aneuploidy was the most indicative parameter of recurrence in bladder tumors. In addition, according to the DNA content and the ploidy level of the aneuploid cell lines, the aneuploid tumors in our group were divided into four types, namely tetraploid tumors, noneuploid tumors with an DNA index (DI) less than or equal to 1.5, hypotetraploid tumors and aneuploid tumors with several cell lines. The results showed that the recurrence rate of tetraploid tumors was relatively lower, and it became higher and higher in the following order: noneuploid tumors with DI less than or equal to 1.5, noneuploid tumors with DI greater than 1.5, and two-aneuploid tumors. This indicates that there are different biological behaviors in tumors with different ploidy patterns. Finally, the correlation between the DNA ploidy pattern and tumor metastases was also discussed.

Carcinoma, Transitional Cell↗
PubMed1992

[Estimation of genetic parameters by using analysis of variance within unit].

In the estimation of heritability, various non-genetic factors must be excluded from the variance of sire or dam. The methods of sib correlation within unit, suggested by professor Sheng Zhilian is commonly used in China. This paper will provide evidence to verify this method theoretically and discuss the application of the method to systematic classification. In addition, in this paper the author suggest some other methods to estimate heritability by using analysis of variance within unit when the blood relationship exists between sire and dam. These methods not only make the estimation procedure of hertability simple but also have the same function of analyzing variance with multiple factors.

Analysis of Variance↗
PubMed1991

Cytogenetic studies on peripheral lymphocytes of members from two multiple familial polyposis coli families.

Cytogenetic studies were carried out on peripheral lymphocytes of 30 members from two typical familial polyposis coli (FPC) families. It was found that, under low folic acid culture conditions, the chromosome aberration rate of FPC family members (10%) was much higher than that of the control group (2.3%). No significant difference in SCE was found between the two groups. We suggest that the chromosome aberration rate under certain conditions may be used as a parameter for the early detection of FPC in certain FPC families. The analysis of fragile sites sensitive to low folic acid in FPC family members revealed that besides the significant increase of 3p14, which is frequently seen in tumor patients, other unique sites (1p22, 1p32 and 6q21) were also present in most of the FPC patients. Fragile sites 1p22, 1p32 and 6q21 are located near certain well known oncogene loci; thus, they may have something to do with the pathogenesis of FPC. The actual relationship between these fragile sites and FPC remains to be elucidated.

Adenomatous Polyposis Coli↗
PubMed1991

Green tea extract inhibits nucleoside transport and potentiates the antitumor effect of antimetabolites.

The present study provides evidence that green tea extract (GTE), consisting of polyphenol components, is a highly active nucleoside transport inhibitor. GTE markedly inhibited radiolabeled thymidine and uridine transport in mouse leukemia L1210 cells, with IC50 values of 3.2 and 8.0 mumol/L, respectively. GTE blocked the rescue effect of exogenous nucleosides and enhanced the cytotoxicity of AraC and MTX to L1210 cells and human hepatoma BEL-7402 cells. GTE markedly potentiated the inhibitory effect of AraC on leukemia L1210 and P388 in mice. These results indicate that GTE is potentially useful when combined with antimetabolites in cancer chemotherapy.

Animals↗
PubMed1991

Cytogenetic studies on a human rectal carcinoma cell line (HR-8348).

Cytogenetic properties of a human rectal carcinoma cell line (HR-8348) established in China are described. The early (29th passage) and late (93rd passage) passage cells were used for chromosome analysis. HR-8348 was found to have an essentially triploid karyotype. This distribution of chromosome numbers was rather dispersed in early passage, whereas it was concentrated in the 65-70 range in late passage. G-banded karyotype analysis also showed that the numerical distribution of chromosomes was dispersed in early passage and was associated with more abnormal chromosomes. In late passage, the numerical distribution became more stable and the number of abnormal chromosomes was reduced. In 60 metaphases analyzed, 10 marker chromosomes were found. The frequencies of M1, M2 and M3 were 100% in both early and late passage cells. The morphological characteristics of these marker chromosomes and their possible origin and role in the pathogenesis of colorectal carcinoma are discussed.

Chromosome Aberrations↗
PubMed1990

Studies on medicamentous inhibitory therapy for esophageal precancerous lesions--3- and 5-year inhibitory effects of antitumor-B, retinamide and riboflavin.

Since 1983, we have been conducting inhibitory therapy for precancerous lesions of the esophagus in two regions of Henan Province considered high-risk areas of esophageal carcinoma. Our goal was to effect a 50% reduction in the canceration rate of marked esophageal dysplasia. By means of a cytological survey, 2531 cases of marked esophageal dysplasia and 3393 cases of mild esophageal dysplasia were selected. The former were randomly divided into 3 groups for antitumor-B (ATB, a mixture of Chinese herbs), retinamide (4-ethoxycarbophenylretinamide) and placebo treatment respectively, and the latter into 2 groups treated with riboflavin and placebo respectively. Treatment was continued for 3 or 5 years (administration rate greater than 90% in all groups) and esophageal cytology reexamined (reexamination rates were 94.1% and 92.5% respectively). Our results were as follows: 1) ATB 3- and 5-year subjects saw the canceration rate of marked esophageal dysplasia drop by 52.2% and 47.3% respectively as compared to control (P less than 0.01). 2) Retinamide lowered the canceration rate by 37.3% after a 3-year treatment period, with this reduction reaching 43.2% after an additional 2 years of treatment with increased dosages (P less than 0.05, P less than 0.01). 3) In the riboflavin group, the canceration rate of mild esophageal dysplasia was reduced by 22.2% and 34.8% after 3 and 5 years of treatment respectively, but these differences were not statistically significant. The above results verify the efficacy of medicamentous inhibitory therapy for esophageal precancerous lesions.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Repair in irradiated ascites tumour cells growing in vivo. An investigation of split doses related to cell cycle.

Split dose irradiation with 2 X 2.5 Gy at intervals of 3 to 48 h was compared with the effect of a single irradiation with a 5 Gy dose in Bp8 mouse ascites sarcoma growing in vivo. The total number of cells and, using rapid-flow cytofluorometry, the proportions of cells in the various parts of the cell cycle were determined up to 10 days after irradiation. In addition, from sequential analyses of the total number of cells in the various compartments of the cell cycle, the flow of cells through the cell cycle was calculated. As judged by the growth in the total number of cells, a rapid repair of at least 20 per cent per h up to 3 h is followed by a slow repair of about one per cent per h during the following 45 h. The proportion of cells in the cell cycle following the conditioning dose did not differ enough to expect a significant influence on the mean radiation sensitivity of the cell population. At split time intervals of 12 to 48 h, after a transient early increase of the flow of cells through the cell cycle, the flow of cells was markedly reduced in all parts of the cell cycle with a maximum 24 to 48 h after the second dose of irradiation. This increase in the cell cycle time was not found following single dose irradiation and may influence the repair of potentially lethal cell damage.

Animals↗
PubMed1983

Comparison between protracted and conventional dose rates of irradiation on the growth of the Bp8 mouse ascites sarcoma.

Four days after inoculation, in vivo growing Bp8 mouse ascites sarcoma was irradiated with 1.75, 2.5 and 5 Gy at a dose rate of 0.0185 Gy/min. The results were compared with those obtained previously at a dose rate of 1.33 Gy/min. Using flow-cytometry and the mitotic index, the total number of tumour cells and the proportion of cells in the various parts of the cell cycle were determined up to 10 days after irradiation. In addition, from sequential analyses of the total number of cells in the various compartments of the cell cycle, the flow of cells through cell cycle was calculated. The total number of tumour cells at the plateau phase of growth, the mitotic index and flow calculations indicated that protracted irradiation was more effective than short-time irradiation following 2.5 Gy; no differences were found following 1.75 Gy, and a lesser effect following 5 Gy. While the cells during protracted irradiation were effectively blocked in G2 and in split-dose experiments a good repair capacity has been demonstrated, redistribution of cells in the cell cycle can apparently not explain the results. Induction of repair, dependent both on dose rate and on total dose, may explain the higher efficiency of protracted irradiation.

Animals↗