Biomedical subjects

C Han

Publications and source records attributed to C Han.

At least 55 records · Page 3Linked to original sources

PubMed2000

[Biomarkers in the studies on chemoprevention of colorectal cancer].

The present study was to investigate the chemopreventive effects of tea on colorectal cancer with a series of biomarkers. The results showed that the number of silver-stained nucleolar organizer dots per nucleus(AgNORs), labeling index(LI) of proliferating cell nuclear antigen(PCNA) of intestinal mucosa, and the expression of ras-p21 protein were significantly reduced in the tea-treated groups(P < 0.01) as compared with the positive control group. Furthermore, tea and tea pigments inhibited the expression of Bcl-2 protein and induced the expression of Bax protein(P < 0.05 or P < 0.01). The study provided evidence supporting that PCNA-LI, AgNORs, Bcl-2, Bax and ras-p21 protein could be used as effective biomarkers for colorectal carcinogenesis in human chemopreventive trials.

Animals↗

PubMed2000

[Effects of tea on aberrant crypt foci and colorectal tumors in rats].

The present study was designed to investigate the chemopreventive effects of green tea and tea pigments (the main component of black tea) on 1,2-dimethylhydrazine (DMH)-induced rat colorectal carcinogenesis. Compared with the positive control group, green tea and tea pigments groups had less numbers of aberrant crypt foci (ACF) (P < 0.01) at the end of week 16. At the end of week 32, all rats in the positive control group developed colorectal tumors with an average of 2.6 tumors per rat, and a mean volume of 294.7 mm3 per tumor, while in the groups drinking green tea and tea pigments, the average numbers of colorectal tumors per rat were only 47.1% and 43.1% of controls respectively, and the mean tumor volume was inhibited by 77.1% and 68.1% respectively. It was concluded that tea pigments had a chemopreventive effect on colorectal tumor and ACF formation can be used as a useful intermediate end point to study chemopreventive effects on colorectal cancer.

1,2-Dimethylhydrazine↗

PubMed2000

[Establishment of monoclonal antibodies against aflatoxin M1].

The monoclonal antibodies against aflatoxin M1 were established. Spleen cells from Balb/c mice immunized with AFM1-oxime-BSA conjugate were fused with murine Sp2/0 myeloma cells. Three hybridoma cell lines secretine monoclonal antibodies against AFM1 were established after the fusion cells subcloned for 3-4 cycles. These antibodies were disignated as 3G2, 3G3 and 6G8, respectively. All of them belonged to the subtype of IgG1. The titres of the antibody in ascites ranged from 1:3.2 x 10(6)-1:20 x 10(6). There was no cross reaction between 6G8 monoclone antibody and other types of aflatoxin.

Aflatoxin M1↗

PubMed2000

Formation, photodissociation and structure of chromium/phosphorus binary cluster ions

Chromium/phosphorus binary cluster ions, [Cr(n)P(m)](+/-), produced by laser (532nm) ablation on a tablet of well-mixed chromium and red phosphorus powder, were studied with a home-built tandem time-of-flight (TOF) mass spectrometer. The clusters thus formed are mostly rich in phosphorus. There is an odd-even oscillation in the intensity of the [CrP(m)](+) series, i.e. the mass peaks of even m are higher than those of odd m. The peaks of [CrP(4)](+) and [CrP(8)](+) are especially prominent, which may be ascribed to the specific stability of P(4) sub-structures. There are also some intense peaks in the spectrum assigned to [Cr(3)P(8)](+), [Cr(4)P(9)](+), [Cr(5)P(11)](+), [Cr(6)P(12)](+), [Cr(8)P(14)](+) clusters, etc., which have stable compositions. The stability of these species is consistent with a simple qualitative electronic structure model, in which the valence electrons of P are filled into the d orbitals of Cr. The photodissociation of some cluster ions was also studied. DFT calculations were performed on three small cluster ions to provide some insight into their structures. Copyright 2000 John Wiley & Sons, Ltd.

Journal Article↗

PubMed2000

Analysis of the measurement precision of arterial lumen and wall areas using high-resolution MRI.

High-resolution MRI may be used to monitor the progression of human carotid atherosclerosis by measuring the lumen and wall area changes over time. The purpose of this study was to analyze the precision of quantitative measurements of lumen and wall areas. Two independent MR scans near the carotid bifurcation were conducted on eight patients within 2 weeks. The error of lumen area measurement was 6. 2%, 9.2%, and 9.7% for T(1), proton density, and T(2)-weighted images, respectively, and the error of wall area measurement was 10. 8%, 10.9%, and 12.0%. The precision of area measurement correlates strongly with image quality.

Algorithms↗

PubMed2000

Cisplatin versus cisplatin combined with piroxicam in a canine model of human invasive urinary bladder cancer.

PURPOSE: More than 12,000 people are expected to die from invasive transitional cell carcinoma (TCC) of the urinary bladder each year in the United States, indicating that more effective therapy is needed. Drugs inhibiting cyclooxygenase (cox) have recently been found to have chemopreventive and antitumor activity and may potentiate the effects of chemotherapy. The purpose of this study was to determine whether cisplatin combined with the cox-inhibitor piroxicam would induce remission more frequently than cisplatin alone in a relevant animal model of human invasive TCC. METHODS: Pet dogs with naturally occurring, histopathologically confirmed, measurable TCC of the urinary bladder were randomized to receive cisplatin (60 mg/m2 i.v. every 21 days) or cisplatin (same dosage) combined with piroxicam (0.3 mg/kg orally every 24 h). Complete staging was performed prior to and at 6-week intervals during therapy. RESULTS: After eight dogs had been evaluated in each treatment group, a significant difference in remission rate was noted (Fisher's Exact test, P < 0.004). Tumor responses in the cisplatin/piroxicam group included two complete remissions (CR), four partial remissions (PR), two stable disease (SD), and no progressive disease (PD). Tumor responses to cisplatin alone in eight dogs were no CR, no PR, four SD, and four PD. Six additional dogs were treated with cisplatin/piroxicam, and in total 10 of 14 dogs had remission (two CR, eight PR). Renal toxicity of cisplatin/ piroxicam was frequent and dose limiting. CONCLUSIONS: Cisplatin/piroxicam induced remission more frequently than cisplatin alone in a canine model of human invasive TCC. Strategies to reduce renal toxicity need to be developed prior to evaluation of cisplatin/piroxicam in humans or general use of this treatment in pet dogs.

Animals↗

PubMed2000

Phase II study of second-line therapy with DTIC, BCNU, cisplatin and tamoxifen (Dartmouth regimen) chemotherapy in patients with malignant melanoma previously treated with dacarbazine.

This study assessed response rates to combination dacarbazine (DTIC), BCNU (carmustine), cisplatin and tamoxifen (DBPT) chemotherapy in patients with progressive metastatic melanoma previously treated with DTIC, as an evaluation of DBPT as a second-line regimen, and as an indirect comparison of DBPT with DTIC. Thirty-five consecutive patients received DBPT. The patients were divided into two groups. Group 1 comprised 17 patients with progressive disease (PD) on DTIC + tamoxifen therapy who were switched directly to DBPT. Group 2 comprised 18 patients not immediately switched to DBPT and included patients who had either a partial response (PR; one patient) or developed stable disease (SD; four patients) with DTIC, or received adjuvant DTIC (nine patients). All except four patients had received tamoxifen at the time of initial DTIC treatment. Median times since stopping DTIC were 22 days (range 20-41) and 285 days (range 50-1,240) in Groups 1 and 2 respectively. In Group 1, one patient developed SD for 5 months and the remainder had PD. In Group 2, there were two PRs, four patients with SD (4, 5, 6, and 6 months), and 11 with PD. These results indicate that the DBPT regimen is not of value in melanoma primarily refractory to DTIC. There were responses in patients not directly switched from DTIC to DBPT, suggesting combination therapy may be of value in a small subgroup of melanoma patients.

Adult↗

PubMed2000

Identification of rice blast fungal elicitor-responsive genes by differential display analysis.

In order to study molecular interactions that occur between rice and rice blast fungus upon infection, we isolated fungal elicitor-responsive genes from rice (Oryza sativa cv. Milyang 117) suspension-cultured cells treated with fungal elicitor prepared from the rice blast fungus (Magnaporthe grisea) employing a method that combined mRNA differential display and cDNA library screening. Data base searches with the isolated cDNA clones revealed that the OsERG1 and OsERG2 cDNAs share significant similarities with the mammalian Ca2+-dependent lipid binding (C2) domains. The OsCPX1 cDNA is highly homologous to peroxidases. The OsHin1 cDNA exhibits homology to the tobacco hin1 gene, whose expression is induced by avirulent pathogens. The OsLPL1 and OsMEK1 cDNAs share homologies with lysophospholipases and serine/threonine mitogen-activated protein (MAP) kinase kinases, respectively. The OsWRKY1 and OsEREBP1 cDNAs are homologous to transcription factors, such as the WRKY protein family and the AP2/EREBP family, respectively. Transcripts of the OsERG1, OsHin1, and OsMEK1 genes were specifically elevated only in response to the avirulent race KJ301 of the rice blast fungus. Our study yielded a number of elicitor-responsive genes that will not only provide molecular probes, but also contribute to our understanding of host defense mechanisms against the rice blast fungus.

Blotting, Northern↗

PubMed2000

Nitric oxide inhibits norepinephrine-induced hepatic vascular responses but potentiates hepatic glucose output.

We previously reported that sympathetic nerve-induced vasoconstriction in the intestine resulted in shear stress induced release of nitric oxide (NO) that led to presynaptic inhibition of transmitter release. In contrast, studies in the liver suggested a postsynaptic inhibition of vascular responses, thus leading to the hypothesis tested here that maintained catecholamine release in the liver would result in maintained metabolic catecholamine action in the face of inhibition of vascular responses. In rats, norepinephrine (NE) induced elevations in arterial glucose content were inhibited by NO synthase antagonism (N(omega)-nitro-L-arginine methyl ester (L-NAME), 10 mg/kg, intraportal) but potentiated by NO donor administration (3-morpholinosydnonimine (SIN-1), 0.2 mg/kg, intraportal). The potentiated effect of SIN-1 was abolished by indomethacin (7.5 mg/kg, intraportal). To confirm the hepatic site of metabolic effect, cats were used so that blood flow and hepatic glucose balance could be determined. SIN-1 potentiated NE-induced glucose output from the liver from 5.0 +/- 0.4 to 7.2 +/- 0.6 mg x min(-1) x kg(-1). The potentiation was blocked by methylene blue, a guanylate cyclase inhibitor. Contrary to the glucose response, L-NAME potentiated but SIN-1 attenuated NE-induced portal vasoconstriction. Thus NO is shown to produce differential modulation of vascular and metabolic effects of NE. Vasoconstriction of the hepatic vasculature is inhibited by NO, whereas the glycogenolytic response to NE is potentiated, responses that are probably mediated by prostaglandin.

Animals↗

PubMed2000

Effect of tea polyphenols and tea pigments on the inhibition of precancerous liver lesions in rats.

The objective of this study was to investigate the inhibitory effect of tea components, tea polyphenols and tea pigments, on precancerous liver lesions in rats. A rat liver precancerous lesion model was established by multiple low-dosage N-nitrosodiethylamine (NDEA) injections, followed by intraperitoneal CCl4 injection and partial hepatectomy (PH). Tea pigments (0.1%) or tea polyphenols (0.1%) were given to Wistar rats in drinking water during the eight weeks of the experiment. The number and area of glutathione S-transferase Pi-positive foci in the rat liver were used as biomarkers of precancerous liver lesions. Western and Northern blot techniques were used to detect rat liver GST-Pi expression at the protein and mRNA levels. At the end of the experiment, tea polyphenols and tea pigments significantly decreased the number and area of GST-Pi-positive foci that were overexpressed in the NDEA-CCl4-PH-treated rats compared with the positive control group. The results also showed that GST-Pi mRNA and protein expression increased significantly in the NDEA-CCl4-PH-treated group, which is consistent with the changing of GST-Pi-positive foci. Tea pigments and tea polyphenols had an inhibitory effect on the overexpression of GST-Pi mRNA and protein in NDEA-CCl4-PH-treated rats. These results suggest that tea pigments and tea polyphenols are effective in preventing the occurrence and progression of precancerous liver lesions in rats.

Animals↗

PubMed2000

A survey on knowledge and skills in the early diagnosis of leprosy in general health services at different levels in Shandong Province, The People's Republic of China.

In the late phase of a leprosy control programme, problems arise with regard to the early detection and treatment of a small number of new incident cases. We describe a study in the province of Shandong, People's Republic of China, on the knowledge and skills regarding leprosy of general health service staff, including rural doctors, paramedical doctors at township level, doctors from county general and provincial hospitals and dermatologists. The results showed that there is a continuing need for suitable training programmes for medical staff in the general health services. Most dermatologists had good levels of knowledge and skills and more than 80% of new cases have been diagnosed in skin clinics in this province since 1990. Their participation in early diagnosis and training of staff should be strengthened.

Adult↗

PubMed2000

The short form of the alternatively spliced flt-4 but not its ligand vascular endothelial growth factor C is related to lymph node metastasis in human breast cancers.

Angiogenesis is essential for tumor growth and metastasis. It is regulated by numerous angiogenic factors, one of the most important being vascular endothelial growth factor (VEGF). Recently, VEGF-C, a new VEGF family member, has been identified that binds to the tyrosine kinase receptors flt-4 [VEGF receptor (VEGFR) 3] and KDR (VEGFR2). Although the importance of VEGF has been shown in many human tumor types, the contribution of VEGF-C and its primary receptor flt-4 to tumor progression is less well understood. We have therefore measured the level of VEGF-C, flt-4, and KDR mRNA by RNase protection assay and the pattern of VEGF-C expression by immunohistochemistry in 11 normal breast tissue samples and 61 invasive breast cancers. No significant difference in VEGF-C expression was observed between normal and neoplastic breast tissues (P = 0.11). There was a significant correlation between VEGF-C and both flt-4 (P = 0.02) and KDR (P = 0.0002), but no association was seen between VEGF-C and either lymph node status (P = 0.66) or number of involved nodes (P = 0.88), patient age (P = 0.83), tumor size (P = 0.20), estrogen receptor status (P = 0.67), or tumor grade (P = 0.35). No significant relationship was present between VEGF-C and vascular invasion (P = 0.30), tumor vascularity (P = 0.21), VEGF-A (P = 0.62), or thymidine phosphorylase expression (P = 1.00). VEGF-C was expressed predominantly in the cytoplasm of tumor cells, although occasional stromal components including fibroblasts were also positive. We could demonstrate no association between lymph node metastasis and either VEGF-C (P = 0.66) or flt-4 (P = 0.4). However, we did observe a significant loss of the long but not the short isoform of flt-4 in tumors compared with normal tissues (P = 0.02 and P = 0.25, respectively), and this difference was largely accounted for by the reduction of long flt-4 in node-positive tumors. These findings strongly support a role for VEGF-C/flt-4 signaling in tumor growth by enhancement of angiogenesis and/or lymphangiogenesis and suggest that differential regulation of these processes may be controlled via flt-4 isoform transcription. They further suggest that the measurement of flt-4 isoform expression may identify a patient group that is likely to have node-positive disease and therefore benefit from additional treatment and also emphasize an additional ligand interaction that could be exploited by anti-VEGFR therapy.

Alternative Splicing↗

PubMed2000

A phase II study of razoxane, an antiangiogenic topoisomerase II inhibitor, in renal cell cancer with assessment of potential surrogate markers of angiogenesis.

Renal cell carcinoma (RCC) is an angiogenic tumor resistant to standard cytotoxic chemotherapeutic agents. Although often responsive to immunomodulatory agents including interleukin 2 and IFN-alpha, the overall results in randomized Phase III studies are disappointing with only modest improvements in overall survival. This Phase II study evaluated the efficacy and tolerability of razoxane, an antiangiogenic topoisomerase II inhibitor, in 40 patients (32 men, 8 women; age: range, 31-76 years; median, 58 years) with inoperable RCC. Twenty patients received razoxane 125 mg p.o., twice a day for 5 days each week for 8 weeks (one cycle). This was repeated in patients with stable disease (StD), but was discontinued after 16 weeks if there was no evidence of an objective response. Because minimal toxicity was seen, subsequent patients (n = 20) were treated until progressive disease (PD) was documented. Of 38 evaluable patients, 11 (29%) had StD for a minimum of 4 months, and the remainder had PD. Median overall survival was 7.3 months. Duration of survival was significantly better in patients with StD compared with those with PD (P = 0.003). The effect of treatment on six potential surrogate serum/plasma (vascular endothelial growth factor (VEGF), basic fibroblast growth factor (bFGF), urokinase plasminogen activator soluble receptor (uPAsr), E-selectin, vascular cell adhesion molecule-1 (VCAM-1) and von Willebrand's factor (vWF) and two urinary (VEGF and bFGF) markers of angiogenesis was evaluated before and after 1 cycle of treatment. Pretreatment serum VEGF and E-selectin levels above the median value were associated with a poor prognosis. Serum VCAM-1 levels and urinary VEGF levels rose significantly after one cycle in patients with PD but not in those with StD. Serum VEGF, bFGF, VCAM-1 and vWF, plasma uPAsr and urinary bFGF levels were significantly higher in PD patients compared with StD patients before and/or after 1 cycle of treatment. In conclusion, razoxane is an antiangiogenic agent that has minimal toxicity and that requires further evaluation in combination with other active agents in the treatment of RCC. Surrogate serum and urinary markers of angiogenesis may have a role to play in predicting disease response and overall survival in RCC.

Adult↗

PubMed2000

[Primary study on immunologic effect of live attenuated hepatitis A vaccine (H2 strain) after booster dose].

OBJECTIVE: To study the immunologic effect of live attenuated hepatitis A vaccine (H(2) Strain, 10(7.0)TCID(50)) after booster and to compare with the results of 1 dose live attenuated hepatitis A vaccine (H(2) Strain, 10(7.0)TCID(50)). METHODS: 42 susceptibles with negative anti - HAV were selected in Zhengding, Hebei province. Each subject received 3 doses live attenuated hepatitis A vaccine at 0, 2, 6 months and was bled at 1, 2, 6, 7, 9, 12 months after vaccination. RESULTS: The seroconversion rate at 1 month after the first dose was 81.4% and reached 100% after the second dose. GMT arrived the peak 2,739 mIU/ml at one month after the third dose, before stared declining. The seroconversion rate kept 100% at 12 months after the first dose, but GMT decreased to 979 mIU/ml. CONCLUSION: The first dose worked as the base of boostering. A booster dose of live attenuated hepatitis A vaccine could induce secondary immune response well. The immunologic effect after booster dose could match the effect with inactivated vaccine and was better than the results of 1 dose live attenuated hepatitis A vaccine. The program seemed to be useful to the protective effect and the immuno - persistence.

Child↗

PubMed2000

[Analysis of clinical characteristic and tendency on inpatients with colorectal cancer in Shanxi Tumor hospital from 1989 - 1999].

OBJECTIVE: To understand the clinical characteristics and variable tendency on inpatients with colorectal cancer admitted to Shanxi Tumor Hospital from 1989 - 1999. METHODS: Statistical analysis on all cases from 1989 - 1999. RESULTS: Results showed that 3,050 cases with colorectal cancer were admitted during 11 years including 2,246 (73.64%) cases of surgical patients. The 1,168 cases males and 1,078 females were with ratio being 1.08/1.0 (M:F). There was no obvious change on the numbers of inpatient from 1991 to 1994, but the numbers was higher than that in 1989 and 1990. The numbers of inpatient rose from 1995 to 1999 year by year. In all the admitted inpatients during the 11 years, 1,348 cases were from countryside and 898 cases from city with the ratio being 1.5/1.0. When adjusted by the general population in 1992, the frequency of the admitted patients was higher in city (14.66/10(5)) than that in countryside (5.96/10(5)). Regarding the distribution of inpatients, it was found higher in Tiayuan city and Jinzhong area than that in else areas. The age of inpatients rose from 40 years and reached high peak in 51 - 70 years. Dukes stages showed that most of inpatients were middle or advanced stage and chief ill location was in rectal (82.36%). Most histological classification referred to adenocarcinoma (56.23%) and papilla adenocarcinoma (20.88%). CONCLUSION: Data suggested that it is very important to strenghen the knowledge of prevention and self-protection of colorectal cancer. Screening and early diagnosis and early treatment should be paid great attention to improve survival rate among high risk population.

ABO Blood-Group System↗

PubMed2000

[Effect of chrysotile and cigarette smoking solution on DNA damage and repair in human alveolar epithelial cells].

OBJECTIVE: To study the effect of chrysotile and solution of cigarette smoke separately or combined on DNA damage and repair. METHODS: Single-cells gel electrophoresis assay was used to detect break in DNA strand and to analyze its repair function in human alveolar epithelial cell line A549, which were exposed to chrysotile or cigarette smoke solution separately or combined for one hour and then immediately cultured for different time. RESULTS: Break in DNA strands was induced obviously in A549 cells after exposure to 40 microg/ml of chrysotile or 2.5 x 10(-4) cig/ml of cigarettes smoke solution for one hour. Repair for DNA break could be seen clearly in chrysotile-treated cells after continuing culture for three hours, and 30.6% had been repaired after culture for four hours. Repair could also be seen clearly in cigarette smoke solution-treated cells after continuing culture for two hours, and 65.2% had been repaired after culture for four hours. Repair of DNA in cells exposed to both chrysotile and cigarette smoke solution combined was similar to that exposed to cigarette smoke solution only. CONCLUSION: Damage to DNA caused by chrysotile is more difficult to repair than that induced by cigarette smoking solution.

Asbestos, Serpentine↗

PubMed2000

[Development of a peristaltic inhibition model in mice].

Diphenoxylate was administered to mice at the dose of 5 mg/kg BW for the development of peristaltic inhibition model for formulating the examination procedure of health foods. An ink solution containing 5% charcoal was then administered 30 minutes later. The length of ink progradation of the small intestine of mice was calculated 25 minutes after the administration of ink. The results in this model was stable and reliable, and it was recommended to use this model to verify the function of health foods.

Animals↗

PubMed1999

[Effects of tea on DMBA-induced oral carcinogenesis in hamsters].

The preventive effects of green tea, tea pigments and mixed tea (a composite of whole water extract from green tea, tea polyphenols, and tea pigments) on 7, 12-dimethylbenz(a) anthracene(DMBA)-induced oral carcinogenesis in golden Syrian hamsters were studied. The hamsters were divided into five groups. i.e. the positive control group(the right buccal pouches of animal was topically treated with 0.5% DMBA in acetone three times per week for 15 weeks), three tea treated groups(1.5% green tea, 0.1% tea pigments and 0.5% mixed tea as the sole source of drinking water from two weeks before starting the DMBA treatment to the end of the experiment) and the negative control group(acetone applied topically). The results showed that in the 1.5% green tea, 0.1% tea pigments and 0.5% mixed tea groups, the inhibitory rates of the average number of tumor per hamster were 42.6%, 50.8% and 67.2% respectively, and the mean tumor burdens were 79% 89% and 95% respectively, compared with the positive control group. In the three tea groups, the frequency of micronucleated cells, the number of silver-stained nucleolar organizer regions (AgNOR), labeling index of proliferating cell nuclear antigen(PCNA) and the level of epidermal growth factor receptor(EGFR) expression in the oral mucosa cells were also less than those in the positive control group. These results clearly indicated that the mixed tea could effectively inhibit DMBA-induced oral carcinogenesis in hamsters. The mixed tea was more effective than green tea or tea pigments in this animal model. Protection of DNA from damage by carcinogen and suppression of cell proliferation was considered as important mechanisms of the anticarcinogenic effects of the mixed tea preparations.

9,10-Dimethyl-1,2-benzanthracene↗