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C Li

Publications and source records attributed to C Li.

At least 397 records · Page 22Linked to original sources
PubMed2000

Immediate post-abortal insertion of the frameless GyneFix IUD: initial experience in China.

The promising results obtained with the frameless GyneFix IUD for interval insertion led to the belief that the technology could be useful for immediate post-abortal application to reduce the number of induced and repeat abortions. IUDs have many advantages and the method is acceptable and safe. However, side effects and expulsion of conventional IUDs remain a problem. In an attempt to minimise these problems, the frameless GyneFix IUD was developed. Clinical studies conducted over the past 14 years have shown that the principles on which the device is based are valid. An increasing bulk of clinical evidence shows that the design characteristics of the device (fixed, frameless and flexible) are responsible for the low expulsion, high effectiveness, and high tolerance and continuation rates.1 Experience with the frameless IUD in China since 1989 confirms the international experience with the device. The present communication is a second report from China with the GyneFix IUD. In the present study the GyneFix IUD is inserted immediately following termination of pregnancy of less than 10 weeks amenorrhea. It is concluded that immediate post-abortal insertion of the frameless IUD is easy and safe, and appears to be as reliable and as effective as when it is inserted at interval. The GyneFix IUD could, therefore, constitute an important new option in the prevention of abortion.

Abortion, Induced↗
PubMed2000

Deferoxamine-induced bone dysplasia in the distal femur and patella of pediatric patients and young adults: MR imaging appearance.

OBJECTIVE: We investigated the MR imaging appearance of deferoxamine-induced bone dysplasia in the distal femur and patella in patients with thalassemia major. MATERIALS AND METHODS: Thirty-five patients with homozygous ss-thalassemia major who were undergoing regular transfusions and chelation therapy underwent coronal T1-weighted MR imaging of the femur, including the femoral head and the distal femoral epiphysis. Additional coronal fat-saturated dual-echo and sagittal T1-weighted images of the distal femur and patella were obtained in 11 patients who were suspected of having distal femoral lesions on the basis of the coronal T1-weighted images of the entire femur. RESULTS: No dysplastic change was detected in the proximal femur on coronal T1-weighted images. In 22 distal femurs of 11 patients, the following abnormalities were detected on MR imaging: blurred physeal-metaphyseal junction (n = 22), distal metaphyseal areas of hyperintensity (n = 21), physeal widening (n = 18), metadiaphyseal lesions (n = 11), epiphyseal lesions (n = 10), and patellar lesions (n = 2). Physeal widening and distal metaphyseal hyperintense areas were all more pronounced peripherally. Of the 21 distal metaphyseal hyperintensities, lateral abnormalities were larger than medial abnormalities in 16. Of the 18 distal femurs in which physeal widening was detected, the lateral widening was more marked than the medial widening in 12. Patients with MR imaging evidence of bone dysplasia have a significantly (p = 0.003) greater height reduction than patients without such evidence of bone dysplasia. CONCLUSION: Deferoxamine-induced bone dysplasia in the distal femur and patella is represented by a spectrum of morphologic changes in the epiphysis, physis, metaphysis, and metadiaphysis on MR imaging.

Adolescent↗
PubMed2000

Comparison of action of paclitaxel and poly(L-glutamic acid)-paclitaxel conjugate in human breast cancer cells.

The new anticancer agent poly(L-glutamic acid)-paclitaxel (PG-TXL) is a conjugate of paclitaxel and the water-soluble polyglutamate carrier. The observation that PG-TXL appears to possess antitumor activity superior to free paclitaxel in preclinical studies suggests that PG-TXL might possess favorable pharmacokinetic properties and/or have a mechanism of action different from that of paclitaxel. The purpose of this study was to compare the pharmacological action of PG-TXL and free paclitaxel in a panel of breast cancer cell lines with emphasis on their ability to induce apoptosis, their effects on cell cycle progression, and their cellular uptake. Morphological analysis and biochemical characterizations demonstrated that both compounds have similar abilities to induce apoptosis in cells expressing wild-type p53 (MCF-7) or mutant p53 (MDA-MB435 and MDA-MB453). Although MCF-7 cells were less sensitive to each compound than MDA-MB435 and MDA-MB453 cells, transfection experiments demonstrated that p53 did not appear to play a significant role in drug-induced cell death with either agent. Flow cytometry analysis further revealed that both free paclitaxel and PG-TXL induced a characteristic G2/M arrest in the cell cycle, consistent with the disturbance of microtubule polymerization as their mechanism of action. Western blot analysis showed that paclitaxel and PG-TXL downregulated HER2/neu expression in a similar fashion. HPLC analysis revealed that paclitaxel was released from the PG-TXL conjugate in vitro. The released paclitaxel, not the glutamic acid polymer, was subsequently transported into the cells. These results suggest that PG-TXL exerts its anticancer activity by continuous release of free paclitaxel, and that the favorable pharmacokinetics and drug distribution of the PG-TXL conjugate in vivo are likely the main factors contributing to its superior anticancer activity.

Antineoplastic Agents, Phytogenic↗
PubMed2000

Cimetidine absorption and elimination in rat small intestine.

The purpose of this study was to determine the characteristics of intestinal absorption and metabolism of cimetidine. The initial finding of the appearance of cimetidine sulfoxide in rat and human jejunum from cimetidine perfusions had prompted an isolation of mucosal membrane transport and enterocyte metabolism contributions in earlier membrane vesicle and microsomal studies, respectively. In this report, perfusion studies in rat small intestine detail regional differences in intestinal elimination. Cimetidine S-oxide appears to a significantly greater extent in the jejunum compared with the ileum. Jejunal metabolite appearance is shown to be a function of the pH-dependent intracellular uptake of cimetidine. Cimetidine permeability decreases with increasing perfusion concentration in both jejunum and ileum. Similar permeability magnitudes and concentration dependence are observed in both regions. Perfusion studies with inhibitors of cimetidine mucosal transport and inhibitors of microsomal S-oxidation provide an inhibition profile suggesting that jejunal cimetidine permeability decreases with increasing intracellular cimetidine concentration. The data support a reduction in paracellular cimetidine absorption as controlled by intracellular cimetidine. This inference is drawn on the basis of mass balance. Because significant appearance of cimetidine S-oxide was previously found in human jejunal perfusions, this region-dependent intestinal elimination process detailed in rats may be relevant to drug plasma-level double peaks observed in clinical studies. Saturation of jejunal metabolism at typical oral doses may limit paracellular absorption of cimetidine in the jejunum and contribute to the double peak phenomenon and to absorption variability.

Administration, Oral↗
PubMed2000

[IL-4 gene transfer induces the differentiation of cells and inhibits the activity of telomerase in hepatoblastoma cells].

OBJECTIVE: To investigate the effects of human interleukin-4(hIL-4) gene transfer on the differentiation and the activities of telomerase in hepatoblastoma cells. METHODS: Retroviral vector (PL-IL-4-SN) was employed to introduce hIL-4 gene into human hepatoblastoma cell line(Hep G2)cells. Trypan blue and Wright's stain, radioimmunoassay, in situ hybridization, flow cytometry, PCR-ELISA were used to determine the change in morphology and cell cycle, the expression of proto-oncogenes, the synthesis of AFP and the activities of telomerase in IL-4 gene transferred tumor cells. RESULTS: The shape of the hepatoblastoma cells tended to become relatively mature; the growth of the cells was significantly suppressed(P<0.05); the synthesis of AFP was reduced from 15.36+/-0. 67 ng x10(6) cells(-1); x24h(-1); to 3.26 +/- 1.43ng x10(6) cells(-1); x 24h(-1); the proliferation of the cells was significantly suppressed(P<0.05); the cell cycle was arrested at G(0)/ G(1) stage; the expression of c-fos, c-jun, c-myc and the activities of telomerase were remarkably decreased in IL-4 gene-modified Hep G2 cells. CONCLUSION: hIL-4 gene transfer could induce the differentiation of heptoblastoma cells and down-regulate the activity of tolemarase in Hep G2 cells.

Cell Differentiation↗
PubMed2000

[A molecular cytogenetic study on chromosome anomalies of chronic myeloid leukemia].

OBJECTIVE: To study the bcr/abl fusion gene in chronic myeloid leukemia (CML) cases with Philadelphia chromosome(Ph) negative, and variant Ph translocations and other chromosome anomalies. METHODS: The status of bcr/abl fusion gene in 8 kinds of chromosome anomalies was tested with dual-color fluorescence in situ hybridization (D-FISH) technique. RESULTS: The positive hybridization was demonstrated in 3 cases of variant Ph CML and other 7 cases of standard Ph, respectively. In 2 cases of Ph-negative CML, one case that had karyotype such as 46,XY,t(9;18) showed positive hybridization, the other case with 46,XY,inv(2) showed negative result. CONCLUSION: The result demonstrates that D-FISH technique is reliable for detecting bcr/abl fusion gene. The existence of negative bcr/abl fusion gene CML implies that some other initial events inducing CML might have occurred in such cases.

Adult↗
PubMed2000

Distribution of CAG repeat size in the dentatorubral and pallidoluysian atrophy (DRPLA) gene in a normal population in Taiwan.

Dentatorubral and pallidoluysian atrophy (DRPLA) is an autosomal dominant neurodegenerative disorder with expansion of trinucleotide CAG repeats in the coding region of the gene. Expansion of the repeat tract beyond the normal range produces gene products with extended polyglutamine tracts. In this study, we analyzed the distribution of the CAG repeats in the DRPLA alleles in a normal Taiwanese population. We observed 15 different alleles and found that the range of the CAG repeat number was from 7-21. The most frequent allele contained 15 CAG repeats that represented 20% of the total analyzed alleles, followed by the 17 repeats (15.8%). The heterozygosity rate of this locus was 88%. Twelve parents-to-children transmissions of the DRPLA alleles in a Machado-Joseph disease family appeared to be normal without any alteration of the CAG repeat numbers. Phenotypes of DRPLA overlapped those of autosomal dominant cerebellar ataxia (ADCA). In order to identify DRPLA patients in Taiwan, we screened six autosomal dominant cerebellar ataxia patients without expansion in known spinocerebellar ataxia genes. All six patients had the repeat numbers within the normal range; thus, the possibility of DRPLA could be excluded.

Alleles↗
PubMed2000

Molecular diagnosis of fragile X syndrome and distribution of CGG repeats in the FMR-1 gene in Taiwanese.

BACKGROUND AND PURPOSE: Fragile X syndrome, the most frequent form of inherited mental retardation, is caused by abnormal expansion of the CGG trinucleotide repeats in the 5' untranslated region of the FMR-1 gene. In this study, we describe the prenatal diagnosis of fragile X syndrome and the distribution of CGG repeat numbers in the FMR-1 gene, which has not been previously reported in Taiwanese. METHODS: Using polymerase chain reaction (PCR), we determined the range of the CGG repeats in the FMR-1 gene in 316 normal individuals (350 X chromosomes) and 349 mentally retarded patients (429 X chromosomes). For prenatal diagnosis of fragile X syndrome, DNA extracted from amniotic fluid cells was used for PCR determination of CGG repeats. RESULTS: Because there were no significant differences between the distribution of the (CGG)n alleles between the mentally retarded and normal subjects, the data were pooled. Among the 779 X chromosomes studied, 24 different alleles were identified with a low of 16 and a high of 45 CGG repeats. The 29 repeat allele was the most common, followed by the 30 and the 28 repeat alleles. We effectively amplified slightly expanded premutation alleles of up to about 90 CGG repeats. In the prenatally diagnosed fetus, a normal 29 repeat allele was found. CONCLUSIONS: Determination of the distribution of the CGG repeats in the FMR-1 gene in Taiwanese is useful in genetic counseling regarding fragile X syndrome. Prenatal molecular diagnosis of the syndrome can be successfully performed using amniotic fluid cells.

Female↗
PubMed2000

[Magnetic drug delivery system--adriamycin-carboxymethyl dextran magnetic nanoparticles].

A novel magnetic drug carrier-carboxymethyl dextran magnetic nanoparticles(CMD MNPs) was prepared. Adriamycin (ADR) was coupled with two types of carrier-neutral dextran MNPs and anionic CMD MNPs, by periodate oxidation. The physico-chemical characteristics and the magnetic guidance effects in vitro and in vivo of ADR-CMD MNPs were studied. The distribution profiles of liver and spleen in mice were studied for both ADR-dextran conjugate MNPs and ADR-CMD conjugate MNPs. The results showed ADR-CMD conjugate MNPs possessed superparamagnetism, the mean diameter was 56 nm, the mass magnetic susceptibility was 1.06 x 10(-4) emu.g-1, and the drug loading was 12.4%. The distribution profiles in liver and spleen revealed that conjugation with neutral dextran MNPs, excessive accumulation of loaded ADR was found in liver and spleen after intravenous administration, while conjugation with CMD MNPs gave a markedly lower concentration in these organs, which indicated less uptake of ADR-CMD conjugate MNPs by reticuloendothelial system(RES) and the advantage of delivering loaded drug to sites other than the RES; thus it opens a new perspective for the active delivery of drug.

Animals↗
PubMed2000

Tumor irradiation enhances the tumor-specific distribution of poly(L-glutamic acid)-conjugated paclitaxel and its antitumor efficacy.

The poly(L-glutamic acid)-paclitaxel (PG-TXL) conjugate has been shown to exhibit significantly greater antitumor activity than conventionally formulated paclitaxel (TXL) against solid tumors (Li et al., Cancer Res., 58: 2404-2409, 1998). Here we report that local tumor irradiation enhanced the distribution of PG-TXL given 24 h later to ovarian OCa-1 carcinoma implanted i.m. in C3Hf/Kam mice. Radiation significantly increased tumor uptake of PG-TXL and tumor vascular permeability, caused elevation of the serum concentration of vascular endothelial growth factor, and arrested OCa-1 cells in the G1 phase of cell cycle. The enhancement factors, as measured by incremental tumor growth delay compared with PG-TXL alone, ranged from 1.36-4.44. Complete tumor regression was also observed at a higher radiation dose (>10 Gy) and a higher PG-TXL dose (>80 mg equivalentTXL/kg). Furthermore, combined radiation and PG-TXL produced a significantly greater tumor growth delay than treatment with radiation and TXL when both drugs were given at the same equivalent TXL dose of 60 mg/kg 24 h after tumor irradiation (enhancement factors, 4.44 versus 1.50). These data suggest that conjugation of TXL to poly(L-glutamic acid) is necessary for improved response and that the supra-additive effect of combined radiation and PG-TXL therapy is due in part to modulation of the enhanced permeability and retention effect of macromolecules by radiation. We propose a treatment strategy combining radiation and macromolecular chemotherapy that may have important clinical implications in terms of scheduling and optimization of the therapeutic ratio.

Animals↗
PubMed2000

Effect of stimulation of shenshu point on the aging process of genital system in aged female rats and the role of monoamine neurotransmitters.

In this experiment, among some aged female rats aged over 18 months, and young female rats aged 3 months whose central noradrenergic nerve endings were injured by ventricular injection of 6-hydroxy-dopamine (6-OHDA), it was observed that catgut embedding at bilateral Shenshu (UB 23) points could obviously shorten sexual cycles, increase the frequency of sexual cycle, and slow down the aging process of the genital system in both the aged rats and in the rats with injured noradrenergic endings. After electroacupuncture (EA) at Shenshu (UB 23) points in the aged rats, the frequency of neuronal discharges in locus coeruleus (LC) was elevated and the activating rate of LC to neurons in the medial preoptic area (MPOA) of the hypothalamus was increased, while obvious effect on nucleus raphes magnus (NRM) and the effect of NRM on MPOA were not marked. It is suggested that stimulation of Shenshu (UB 23) point can strengthen the excitability of noradrenergic neurons, activate the ascending pathway of the brain stem--hypothalamus, raise the catecholamine (CA)/5-hydroxytryptamine (5-HT) ratio in the hypothalamus of the aged rats, so as to delay the aging process of the genital system.

Acupuncture Points↗
PubMed2000

Actions of NO and INOS on endotoxin induced rat acute lung injury and effect of rhubarb on them.

This study is to explore the actions of nitric oxide (NO) and inducible nitric oxide synthase (iNOS) on endotoxin (lipopolysaccharide, LPS) induced rat acute lung injury (ALI) and effect of Rhubarb on them. LPS was injected into the sublingual vein of male Wistar rats to prepare ALI animal models. The rats were divided into 4 groups: LPS, control, Rhubarb, and dexamethasone. Macroscopic and histopathological examinations of the lung specimens were performed and the biological indexes of lung, including wet weight/dry weight, the rate of neutrophils and protein content in the pulmonary alveolar lavage fluid, pulmonary vascular permeability and pulmonary alveolar permeability were observed. In the mean time, the contents of serum NO and the activities of lung tissue homogenate iNOS were measured. The results showed that in the LPS group, the injury and celluar infiltration in the pulmonary stroma and alveoli were more prominent than that in the control group. Lung wet weight/dry weight, the rate of neutrophils, protein content, pulmonary alveolar permeability, pulmonary vascular permeability were significantly increased (P < 0.01); NO and iNOS were also markedly elevated (P < 0.01). In the groups of dexamethasone and Rhubarb, the histopathological changes were significantly milder, and all the above biological indexes of lung injury and the contents of NO and the activities of iNOS were correspondingly decreased (P < 0.05). The above data demonstrate that NO and iNOS play an important role in the onset of ALI; dexamethasone and Rhubarb interfering treatment can ameliorate lung injury and decrease the concentrations of NO and the activities of iNOS, showing that through inhibiting the levels of NO and the activities of iNOS, these 2 agents exert protective effect on ALI induced LPS.

Animals↗
PubMed2000

Spirochete periplasmic flagella and motility.

Spirochetes have a unique structure, and as a result their motility is different from that of other bacteria. They also have a special attribute: spirochetes can swim in a highly viscous, gel-like medium, such as that found in connective tissue, that inhibits the motility of most other bacteria. In spirochetes, the organelles for motility, the periplasmic flagella, reside inside the cell within the periplasmic space. A given periplasmic flagellum is attached only at one end of the cell, and depending on the species, may or may not overlap in the center of the cell with those attached at the other end. The number of periplasmic flagella varies from species to species. These structures have been shown to be directly involved in spirochete motility, and they function by rotating within the periplasmic space. The mechanics of motility also vary among the spirochetes. In Leptospira, a motility model developed several years ago has been extensively tested, and the evidence supporting this model is convincing. Borrelia burgdorferi swims differently, and a model of its motility has been recently put forward. This model is based on analyzing the motion of swimming cells, high voltage electron microscopy of fixed cells, and mutant analysis. To better understand spirochete motility on a more molecular level, the proteins and genes involved in motility are being analyzed. Spirochete periplasmic flagellar filaments are among the most complex of bacterial flagella. They are composed of the FlaA sheath proteins, and in many species, multiple FlaB core proteins. Allelic exchange mutagenesis of the genes which encode these proteins is beginning to yield important information with respect to periplasmic flagellar structure and function. Although we are at an early stage with respect to analyzing the function, organization, and regulation of many of the genes involved in spirochete motility, unique aspects have already become evident. Future studies on spirochete motility should be exciting, as only recently have complete genome sequences and tools for allelic exchange mutagenesis become available.

Borrelia burgdorferi Group↗
PubMed2000

[Chromosome localization of the dentinogenesis imperfecta type II locus].

OBJECTIVE: To scrutinize the linkage between dentinogenesis imperfecta type II and chromosome 4q21 in a Tianjin-Tanggu family. METHODS: Blood samples were collected from 13 members of the family. DNA was analyzed with 4 short tandem repeat polymorphisms markers UGATA62A11, DSP(P), SPP1 and D4S1563 Y using fluorescence-based PCR. The linkage between four markers on chromosome 4q21 and dentinogenesis imperfecta type II was tested by Lod score analysis. RESULTS: GATA62A11 and DSP(P) suggested linkage and yielded a Lod score of 1.63 at theta =0, and 1.68 at theta =0 by means of the MLINK software, respectively. Genotype and haplotype were acquired. CONCLUSION: The disease gene of the dentinogenesis imperfecta type II family is located on chromosome 4q. The result will be helpful for the further identification of the dentinogenesis imperfecta type II gene.

Chromosome Mapping↗
PubMed2000

[Clinical study on morphological characteristics of placenta in severe pregnancy induced hypertension].

OBJECTIVE: To study morphological characteristics of placenta in severe pregnancy induced hypertension (SPIH) and its relationship to pregnant outcome. METHODS: Morphological changes were observed by light microscopy; Blood biochemical analyses were used to predispose pregnant outcome. RESULTS: Difference in pathological changes of placental bed between normal term pregnancy (NTP) and SPIH groups was significant: the placental weight, proliferation of cytotrophoblasts, numbers of the placental villi with syncytial knots, thickness of basal lamina, fibrinoid necrosis and deposition of matrix, stromal edema and fibrosis of villi, the vascular numbers of villi, stasis; lack of physiologic changes in decidual spiral arteries. Clinical examination showed that the rate of anemia, thrombocytopenia, blood concentration, hypoproteinemia, ascites, eye ground artery spasm in SPIH were higher in NIT. CONCLUSIONS: Pathological changes of placenta play important roles in development of SPIH, and the pathological changes are paralleled with the severity of the disease.

Adult↗
PubMed2000

Nuclear factor kappaB activation in acute appendicitis: a molecular marker for extent of disease?

Nuclear factor-kappaB (NF-kappaB) has been demonstrated to regulate the transcription of target genes and stimulate inflammatory cytokine responses in a variety of inflammatory diseases. Preliminary studies have demonstrated that NF-kappaB is activated early in acute inflammation and sepsis and may serve as an indicator of clinical severity. The present study was designed to evaluate the degree of activation of NF-kappaB in patients with acute appendicitis and correlate activation with clinical extent of disease. Ten patients with acute appendicitis and five control patients (elective inguinal hernia repair) were evaluated by assaying NF-kappaB activity preoperatively and 12 to 18 hours postoperatively. Assaying of NF-kappaB was determined by binding activity for consensus probes in nuclear extracts from peripheral mixed white blood cells obtained by venous puncture. The bands of NF-kappaB activity from gel electrophoresis were quantified with a phosphor imager and reported as units of integrated intensity. The preoperative NF-kappaB activity was increased in all patients with appendicitis versus the controls [mean 151 (range 97-189) vs mean 50.3 (range 13.7-77); P < 0.0001]. The increased NF-kappaB activity also correlated with length of time of symptoms before operation. The patients who were symptomatic for less than 24 hours had an average NF-kappaB value of 103 (range 97-105) versus 171.4 (range 152-189) (P < 0.0001) in those who were symptomatic 24 or more hours. The NF-kappaB activity did not correlate with the white blood cell count. Postoperative NF-kappaB binding activity in the appendicitis patients dropped to minimal levels (mean 50.3), even lower than the control patients' baseline values (mean 55.6). Control patients demonstrated low baseline values preoperatively and a slight rise postoperatively [mean 50.3 (range 13.7-77) vs mean 100 (range 45-186)]. We conclude the following: (1) NF-kappaB binding activity is elevated in patients with acute appendicitis and correlates with symptoms longer than 24 hours. (2) This increased activity returns to baseline values within 18 hours after appendectomy. (3) Molecular indicators of inflammation may have a role in both staging surgical inflammatory conditions and predicting ultimate outcome.

Acute Disease↗
PubMed2000

[Determination of serum cytokines in individuals with HCV infection].

OBJECTIVE: To investigate the immunopathogenesis of chronic hepatitis C virus (HCV) infection. METHODS: Serum T-helper lymphocyte (Th1) cytokines (IFN-gamma, IL-2) and Th2 cytokines (IL-4, IL-10) were measured by ELISA in 18 individuals with chronic HCV infection 10 persons of chronic HBV infection and 11 normal persons. RESULTS: IL-2 (P <0.05), IL-4 and IL-10 (P <0.025, P <0.001) were significantly increased in HCV infected hosts as compared to 11 normal controls, the production of Th2 cytokines was more predominant. CONCLUSIONS: An enhanced Th2 responses is present in HCV infection, which may he responsible for the chronicity of HCV infection.

Adult↗