Biomedical subjects

C Y Ji

Publications and source records attributed to C Y Ji.

At least 19 recordsLinked to original sources

PubMed2001

[Analysis of mass minimization of Thermoelectric Integrated Membrane Evaporation Subsystem in waste water processing].

OBJECTIVE: To minimize in the system level the designed mass of Thermoelectric Integrated Membrane Evaporation Subsystem (TIMES) of Environment Control Life Support System (ECLSS) in manned spacecraft, when the requirement of the production rate of fresh water and its hygiene is fulfilled. METHOD: According to the characteristics of the operational process of TIMES, the physical and mathematical model for fluid flow, heat transfer and mass composition in its main parts were established to investigate numerically the relation between the system mass and those parameters associated with the structure and operation of the system. RESULT: The system mass depended not only on the structural parameters and operational parameters of TIMES, but also on the operational characteristics of power subsystem and thermal control subsystem. The relative mass covered a large part of the system mass. CONCLUSION: There existed an optimum of the number of thermoelectric cooling parts and flow rate of circular waste water of the TIMES when the designed system mass was minimum. Moreover, higher condensation pressure in the system contributed to lower system mass.

Ecological Systems, Closed↗

PubMed1999

Serum IGF-binding protein-6 and prostate specific antigen in breast cancer.

OBJECTIVE: Recent studies have demonstrated the presence of the IGF-binding proteins (IGFBPs) and prostate specific antigen (PSA), an IGFBP protease. in human breast tissue. We sought to investigate the differences in serum IGFs, IGFBP-1, -3 and -6, and PSA between patients with surgically proven breast cancer and patients with benign breast disease. DESIGN AND METHODS: Concentrations of IGFs, IGFBP-1, -3 and -6, and PSA were determined in the sera from 57 patients with breast cancer (CA), and 46 women with benign breast disease (BBD) using immunoassays for IGFs and IGFBPs and an ultrasensitive ELISA for PSA. RESULTS: The mean (+/- S.E.M.) serum IGFBP-6 level in the CA group, 127 (16) ng/ml, was statistically significantly lower than in the BBD group, 157 (10) ng/ml (P = 0.016). Patients with CA had an elevated geometric mean serum PSA level of 0.018 (range: 0.0015-0.107) ng/ml, compared with 0.007 (range: 0.0015-0.019) ng/ml in women with BBD (P = 0.025). Mean serum IGFBP-1 concentrations were significantly lower in the CA group, 16 (2) ng/ml, versus 37 (4) ng/ml in the BBD group (P = 0.001). Mean serum IGFBP-3 concentrations were also lower in the CA group versus the BBD group, at 1981 (65) ng/ml, versus 2603 (140) ng/ml (P = 0.002) respectively. In the CA group, statistically significant correlations between PSA and IGFBP-6 (r = 0.413; P = 0.001), and between PSA and IGFBP-1 (r = -0.329; P = 0.021) were seen. Differences in IGF-I and -II between the two groups were not statistically significant. CONCLUSION: Lower serum concentrations of IGFBP-6, -3 and -1, but higher PSA concentrations were seen in the breast cancer group, and collectively these would suggest that there is an increase in bioavailable IGF-I in breast cancer.

Breast Neoplasms↗

PubMed1998

Tamoxifen alters levels of serum insulin-like growth factors and binding proteins in postmenopausal breast cancer patients: a prospective paired cohort study.

BACKGROUND: Recent data suggest that tamoxifen may act by altering serum levels of insulin-like growth factors (IGFs) and their binding proteins (BPs). This prospective paired cohort study evaluated the influence of tamoxifen on serum levels of IGFs and BPs in postmenopausal patients with breast cancer. METHODS: Blood was collected from 32 postmenopausal patients with breast cancer before and during tamoxifen therapy for at least 6 months. All patients had undergone primary surgery. Serum concentrations of IGF-I, IGF-II, BP-1, and BP-3 were determined by immunoradiometric assays, and Western ligand blots provided a semiquantitative measurement of BP-2, BP-3, and BP-4. Statistical analysis was performed by paired Student's t-test. RESULTS: Mean serum IGF-1 level was significantly lower after tamoxifen treatment (pretreatment: 116.2 ng/mL+/-13.6 [SEM] vs. posttreatment: 77.5 ng/mL+/-7.8; P=.003). In contrast, mean IGF-II levels increased from 651.5+/-62.2 ng/mL to 812.5+/-35.1 ng/mL during treatment (P=.006). Posttreatment levels of BP-1 (92.9 ng/mL+/-7.5) were significantly higher compared to the pretreatment values (28.1 ng/mL+/-4.7; P <.001). Serum concentration of BP-3 also was elevated (pretreatment: 2228.1 ng/mL+/-145.2 vs. posttreatment: 3539.1 ng/mL+/-172.3; P <.001). Densitometric measurements showed a similar significant increase in BP-3 (P <.001) as well as BP-4 (P=.017) after hormonal therapy. Levels of BP-2 were not influenced by tamoxifen treatment. CONCLUSIONS: These significant alterations in serum concentrations of IGFs and BPs with tamoxifen therapy suggest that the IGF system is a potential mechanism by which tamoxifen exerts its growth inhibitory effect on breast carcinomas.

Aged↗

PubMed1998

Altered serum levels of insulin-like growth-factor binding proteins in breast cancer patients.

BACKGROUND: Insulin-like growth factor 1 (IGF-1) has mitogenic properties for breast cancer cell lines and has been proposed to be an important factor in breast carcinogenesis. We hypothesized that differences in IGF-1 or its binding proteins might increase susceptibility to breast cancer. This case-control study was designed to investigate whether patients with breast cancer have altered levels of either IGF-1 or its intermediary modulatory proteins, the IGF binding proteins (BP). METHODS: Serum was collected from 90 patients (63 with breast cancer and 27 with benign breast disease) after an overnight fast and before surgery. IGF-1, BP1, and BP3 levels were determined by immunoradiometric assays. In a subset of 66 patients, Western ligand blots were also performed for a semiquantitative measurement of functioning BP levels. A forward stepwise logistic regression model to adjust for other confounding variables (age, menopausal status, parity, age at menarche, use of oral contraceptives, history of breast biopsy, family history of breast cancer, hormone replacement therapy, and body-mass index) was used in the multivariate analysis. RESULTS: Serum IGF-1 levels were similar in cases and controls. However, levels of BP3 (p < 0.001), BP4 (p < 0.01), and BP1 (p < 0.05) were significantly associated with risk of breast cancer. The level of BP3 was the most significant factor predictive of breast cancer. The odds ratio for breast cancer in women with BP3 levels >2066 ng/ml was 0.18 (95% CI, 0.05-0.55). Correspondingly, women with BP1 levels higher than 39 ng/ml had an odds ratio of 0.21 (95% CI, 0.07-0.68) for breast cancer. When considering only cancer patients (n = 63), decreasing levels of BP4 (p < 0.01) and increasing levels of BP1 (p < 0.02) were significantly associated with progesterone receptor positivity (PR+) in the tumor. The odds ratio of PR+ in patients with BP1 levels higher than 34 ng/ml was 7.49 (95% CI, 1.5-37.4). Better grade of tumor (well and moderately differentiated) was observed in patients with higher levels of BP3 (p < 0.03). CONCLUSIONS: Distinct differences in BP profiles exist among patients with breast cancer and also among those with high-grade, hormonal receptor-negative tumors. These findings suggest that the bioavailability of IGF-1 as mediated by its binding proteins may participate in both breast carcinogenesis and selection of more aggressive breast carcinomas.

Age Factors↗

PubMed1998

Urinary 2/16 alpha-hydroxyestrone ratio: correlation with serum insulin-like growth factor binding protein-3 and a potential biomarker of breast cancer risk.

Metabolism of estradiol occurs via two mutually exclusive hydroxylative pathways, yielding metabolites of divergent biological properties. 2-hydroxyestrone (2OHE1) is anti-estrogenic while 16 alpha-hydroxyestrone (16 alpha OHE1) is a potent estrogen. The ratio of 2OHE1 to 16 alpha OHE1 (2/16 alpha-OHE1 ratio) represents the net in vivo estrogenic activity. In this study, we sought to determine if the urinary 2/16 alpha-OHE1 ratio could be a predictor of breast cancer risk and the factors which influence this ratio. Variables analysed included age at diagnosis, menopausal status, parity, use of oral contraceptives, body mass index, serum levels of insulin-like growth factor-I (IGF-I), IGF binding proteins (BPs) and the presence of breast cancer. Serum and urine were collected from 65 breast cancer patients and 36 controls after an overnight fast. Urinary estrogen metabolites were measured by enzyme immunoassays while serum levels of IGF-I, BP-1 and BP-3 were determined by immunoradiometric assays. 2OHE1 levels and 2/16 alpha-OHE1 ratios were significantly lower (P < 0.05) while 16 alpha OHE1 levels were higher (P < 0.01) in cancer patients. Multiple linear regression analysis showed that levels of urinary metabolites were influenced by parity and breast carcinoma. 2/16 alpha-OHE1 ratio correlated positively with serum BP-3 level (P = 0.03). By multiple logistic regression, 2/16 alpha-OHE1 ratio was the most significant factor predictive of breast cancer. The odds ratio for women with higher 2/16 alpha-OHE1 ratios was 0.10 (0.03-0.38, 95% confidence interval). In conclusion, the profile of urinary estradiol metabolites was distinctly altered in breast cancer patients. In addition, BP-3 may be a potential mechanism by which estradiol metabolites influence breast cancer progression. As 16 alpha OHE1 has been shown to initiate neoplastic transformation of mammary epithelial cells, the 2/16 alpha-OHE1 ratio may serve as a biomarker of increased risk of breast cancer.

Age Factors↗

PubMed1997

Risk factors for breast carcinoma in Singaporean Chinese women: the role of central obesity.

BACKGROUND: The incidence of breast carcinoma in Singapore has nearly doubled over the past 25 years. This prospective case-control study involving 1086 women (204 cases and 882 controls) was conducted to determine significant factors associated with the risk of breast carcinoma among Chinese women in Singapore ages 45 to 69 years. METHODS: A forward stepwise logistic regression model adjusted for confounding variables of age, age at menarche, menopausal status, parity, age at first and last delivery, use of oral contraceptives, hormone replacement therapy, family history of breast carcinoma, history of benign breast biopsy, smoking history, height, weight, body mass index, and waist to hip ratio was used. RESULTS: Central obesity as indicated by women with a larger waist to hip ratio was associated with highest risk for breast carcinoma (odds ratio [OR]: 9.18; 95% confidence interval [CI],4.8-17.5 comparing last and first quintile; P < 0.0001, chi-square test for trend). Significant trends were also noted for increasing height and breast carcinoma risk (P = 0.003, chi-square test). Women who were taller than 159 cm (OR: 2.3; 95% CI, 1.4-3.9) had approximately twice the risk of women shorter than 150 cm. Body mass index as a measure of generalized obesity did not significantly predict risk for breast carcinoma. Reproductive and menstrual factors significantly related to risk for breast carcinoma were number of deliveries (OR: 0.81; 95% CI, 0.7-0.9; P < 0.001), age at last delivery (P = 0.03), and use of hormone replacement therapy (OR: 0.54; 95% CI, 0.3-0.9; P = 0.01). Previous breast biopsy for benign disease was also associated with a higher risk for breast carcinoma (OR: 3.5; 95% CI, 2.1-5.7; P < 0.001). CONCLUSIONS: The authors conclude that the risk of breast carcinoma is strongly associated with changes in lifestyle related to caloric intake (central obesity and height) and reproductive or menstrual factors (number of deliveries, age at last delivery, age at menopause, and breast feeding). Better and excess nutrition in early and later years of life and fewer births (related to rapid urbanization) may explain in part the increasing incidence of breast carcinoma occurring in Singapore.

Aged↗

PubMed1997

Loss of c-met protooncogene in primary and metastatic sites of breast cancer.

BACKGROUND: It has been proposed that clones of tumor cells acquire higher metastatic potential as a result of specific genetic alterations. This study was designed to determine the role of the c-met protooncogene in systemic spread by comparing the loss of the c-met protooncogene between primary and metastatic breast carcinomas. METHODS: Only patients who had not received chemotherapy or radiotherapy in the preceding 6 months were included in this study. Histologically proven malignant tissue was obtained from the primary tumor, involved nodes, and distant metastatic and recurrent tumors of patients with breast carcinomas. Allelic loss of the c-met protooncogene in tumor tissue was determined by Southern blotting using a polymerase chain reaction-generated 347-bp human met-H probe. Restriction digestion was performed using Taq I and Msp I, with the patient's lymphocyte DNA as controls. RESULTS: Of 52 patients, lymphocyte DNA from 36 patients was heterozygous for the c-met protooncogene (69% informative). Forty-six tumors from these 36 patients were analyzed. Four of 30 primary tumors (13%) showed allelic loss of c-met. Of the nine nodal metastases examined, three (33%) showed allelic loss of the c-met protooncogene. Of seven distant metastatic breast tumors or recurrent disease, two (29%) showed allelic loss (both in patients with skin metastasis in the chest wall). CONCLUSIONS: Allelic loss of the c-met protooncogene was detected in both primary (13%) and metastatic sites (31%) of breast cancer. Although a higher proportion of allelic loss of c-met was noted in nodal and distant/recurrent disease, the difference when compared with the primary tumor was not statistically significant. These findings indicate a limited role of the c-met protooncogene in breast cancer metastases.

Adult↗

PubMed1996

Prognostic significance of p53 overexpression and mutation in colorectal adenocarcinomas.

The p53 tumour-suppressor gene is found altered in the majority of colorectal cancers. Lesions include allelic loss, mutation of the gene and overexpression of the p53 protein. All of these lesions have been analysed for prognostic significance, and whereas both mutation and allelic loss have been shown to be reasonably useful markers of prognosis, the utility of overexpression of the p53 protein is more ambiguous. Given that many authors use p53 overexpression as a marker for point mutation this issue is of some importance. We have therefore examined 100 colorectal carcinomas for mutation of the p53 gene, as well as overexpression of the p53 protein. Results show that whereas mutation of the p53 gene is associated with p53 overexpression, the degree of association depends, at least in part, upon the particular antibody used. Moreover, although mutation of the p53 gene does provide prognostic information, overexpression of the p53 protein, as detected with two antibodies, does not. These results suggest that immunohistochemistry is not a suitable alternative to direct detection of mutation in assessing prognosis in colorectal cancer patients.

Adenocarcinoma↗

PubMed1993

[Relationship between step test index and maximal aerobic capacity in female adolescents].

The change pattern of step test index (STI) in female adolescents and its relationship with their maximal aerobic capacity were studied. Two hundred and thirteen girls aged 10 to 19 participated in the study. The physical and functional characteristics of the girls with higher STI scores were compared with those with lower ones. STI scores declined with age due to their increasing ratio of weight-to-height during puberty. The maximal aerobic working capacity was estimated by multiple regression analysis with the Quetelet Index (weight/height x 100) into the equation, and its accuracy of the prediction improved.

Adolescent↗

PubMed1992

[The multivariate canonical discriminant analysis between physical growth and nutrition status of children and youth].

This paper is on studying the relationship between physical growth and nutrition status of children and youth by using multivariate canonical discriminant analysis. 3,790 boys and girls of 7-19 yrs of age were classified into four groups according to the height-for-weight method. Then, by using seven physical measures as predict variables, canonical discriminant functions were set up for boys and girls respectively. The backward substitutional test showed that the coincidence ate was quite high, 90.90% for boys and 92.47% for girls respectively. The susceptibility of various physical measures in reflecting children's nutrition status was analysed, and the practical use of these discriminant functions was discussed.

Adolescent↗

PubMed1991

Adaptation of the viral haemorrhagic disease virus of rabbits to the DJRK cell strain.

Liver emulsion of rabbits which had died of viral haemorrhagic disease (VHD) was inoculated onto DJRK cell culture. After two passages, specific cytopathic effect was observed. Immunofluorescence was found in the nucleus at the early stage of infection and later also in the cytoplasm. The virus propagated in cell culture at the fifth, tenth and sixteenth passages was found to cause typical VHD. Electron microscopy showed that there were numerous virions in the infected cells. The cultured virus, inactivated with formaldehyde, could elicit haemagglutination inhibition antibodies in the inoculated rabbits and protect them against the challenge of virulent VHD virus.

Animals↗

PubMed1991

Systematic morphogenesis of the viral haemorrhagic disease virus in infected rabbits and in adapted cell culture.

The morphogenesis of viral haemorrhagic disease virus (VHDV) of rabbits in infected cell cultures and in tissues and cells from infected animals has been observed systematically by electron microscopy. Viral particles have been found to assemble through a condensation process within the nucleus of infected cells, having passed partially into the cytoplasm through disrupted nuclear membranes, enlarged nuclear pores or perinuclear space. Late in infection, both mature and immature virions are observed in the cytoplasm; these are often aggregated or interspersed and remain cell-associated long after infection. Release of the virus occurs when the cell finally lyses. In studies of the localisation and development of VHDV antigens, the viral antigens have been observed to appear first in the nucleus of infected cells and often thereafter in the cytoplasm. This finding is very similar to observations made by electron microscopy.

Animals↗

PubMed1991

[Comparison of somatotype between Chinese and Japanese children and youth by using Heath-Carter method].

This study was designed to compare the different somatotype growth of Chinese and Japanese boys aged 7 through 17. 2,074 subjects participated in it. Their somatotypes were analysed by using Heath-Carter method and their morphological varieties compared. Significant differences were found not only in their limb length and bone width, but also in their muscle circumferences and skinfolds. These differences showed the superiority of Chinese boys in ectomorph factor and the Japanese boys in endomorph and mesomorph factors respectively. The somatotype distributions of these two nations were also quite different at different ages, although they showed similar changing trend of somatotype around adolescent growth spurt.

Adolescent↗

PubMed1986