Biomedical subjects

L Xie

Publications and source records attributed to L Xie.

At least 73 records · Page 4Linked to original sources

PubMed2000

Gender difference in letrozole pharmacokinetics in rats.

AIM: To study gender difference in letrozole (Letr) pharmacokinetics in rats. METHODS: Letr concentrations in plasma and tissues were determined after ig administration of Letr 2 mg/kg. Recoveries of Letr in urine and feces were also analyzed. RESULTS: Marked gender differences were found 6 h after ig Letr 2 mg/kg, the plasma concentrations of Letr in male rats were significantly (P < 0.01) lower than those in female rats. For example, at 24, 36, 48, and 72 h after administration, plasma concentrations in female rats were about 3.3, 5.6, 10.5, and 7.4-fold of that of male rats, respectively. AUC value of Letr in male was only about one-third of that in female rats. Estimated terminal phase half-lives (T1/2) were 10.5 and 40.4 h, respectively. In female rats, cumulative excreted fractions of Letr in urine and feces were 5.8% +/- 1.4% and 6.6% +/- 1.1% within 120 h after administration, respectively, but in male rats, the excreted fractions of Letr in urine and feces were only 1.30% +/- 0.59% and 0.87% +/- 0.31%. Letr concentrations in female rat tissues were significantly (P < 0.01) higher than those in male rat tissues 24 h after administration. CONCLUSION: There are marked gender differences in Letr pharmacokinetics in rats.

Animals↗

PubMed2000

[Detecting Epstein-Barr virus in nasopharyngeal carcinoma tissue using in situ polymerase chain reaction].

OBJECTIVE: To develop a sensitive non-isotopic method for in situ detection of Epstein-Barr virus (EBV) in paraffin-embedded section of nasopharyngeal carcinoma (NPC) tissue. METHODS: The EBV BamHI-W fragment labeled with digoxigenin as probe was used to perform in situ hybridization and PCR in situ hybridization (in situ PCR). RESULTS: The method of in situ PCR for the detection of EBV in NPC tissue was proved to be much more sensitive than in situ hybridization. CONCLUSION: Hybridization in situ of PCR product is useful to detect EBV in NPC tissues.

Adenocarcinoma↗

PubMed2000

[A report on investigation and clinical application of corneal storage media].

OBJECTIVE: To develop intermediate term storage media suitable for Chinese eye banks. METHODS: Corneal buttons of rabbits were stored in DX solution freshly prepared. After storage for several days, the survival rate of the corneal endothelial cells was examined, enzymohistochemical staining and ultrastructural examinations were carried out for the buttons. Thirty-seven human corneas stored in DX solution for 3 - 11 days were used for corneal transplantation, clinically. RESULTS: There was no significant difference between rabbit corneal buttons stored in DX sol. and in Optisol in any indices studied. 37 grafts were all transparent in 1 week after transplantation, and the mean endothelial cell density was (2,204.56 +/- 689.56) cells/mm(2). CONCLUSION: As a safe and efficient intermediate term (about 1 week) storage medium, DX sol. is appropriate for Chinese eye banks.

Adrenal Cortex Hormones↗

PubMed2000

[Experimental study on herpes simplex virus-1 functional gene latency in cornea].

OBJECTIVE: To investigate the possible existence of herpes simplex virus-1 (HSV-1) functional gene latency in cornea. METHODS: A herpes simplex keratitis (HSK) model was established in New Zealand White (NZW) rabbit corneas, latently infected corneas were transplanted to one eye of each naive NZW rabbit. One week after the operation, the corneal buttons were removed and divided into three portions. One portion was processed for HSV-1 antigen detection, another was for HVS-1 latency associated transcript (LAT), thymidine kinase (TK) and DNA polymerase gene detections by polymerase chain reaction (PCR), and the last portion after tissue culture for 3 weeks, it was co-cultured with rabbit kidney cells (RK) for one week, then the expression of HSV-1 antigen in the RK cells and this portion of corneal button was detected. RESULT: In the 15 corneal samples negative for HSV-1 antigen, LAT gene was detected in 8 samples, TK gene in 10 and DNA polymerase gene in 6 samples. HSV-1 antigen was detected in 3 samples of RK cells and 6 cultured corneal samples. CONCLUSION: HSV-1 functional genes are retained in latently infected cornea.

Animals↗

PubMed2000

[Secondary glaucoma after penetrating keratoplasty].

OBJECTIVE: To investigate the etiology and management of secondary glaucoma after penetrating keratoplasty (PKP). METHODS: Eighty cases (80 eyes) with secondary glaucoma occurring in 1,450 cases (1,500 eyes) of PKP, its causes, time of onset and the relationship with the primary disease were analyzed. According to different causes, they were treated with different therapies. RESULTS: The intraocular pressure (IOP) of 63 cases (63 eyes) became normal after drug treatment for 2 - 3 weeks. In 17 cases (17 eyes) who had received antiglaucomatous operations, 13 cases' (13 eyes) IOPs were normal and 4 cases' (4 eyes) still high. CONCLUSIONS: Accurate perioperative management can decrease the incidence of secondary glaucoma after PKP. The majority of secondary glaucoma can be controlled by different therapies according to different causes.

Adolescent↗

PubMed2000

[A preliminary report of ocular surface disease treated by limbal transplantation].

OBJECTIVE: To evaluate the effect of ocular surface disease treated by limbal transplantation. METHODS: In a prospective study, 5l eyes of 50 patients were treated with three kinds of surgical techniques: first, conjunctival limbal autograft (CLAU) transplantation; second, corneal lamellar allograft combined with limbal autograft transplantation and third, corneal lamellar allograft combined with limbal allograft transplantation. Their effects were evaluated. RESULTS: All of the 18 patients of CLAU group were cured. The second surgical technique resulted in restoration of a stable ocular surface in 19 of 20 cases. 10 patients' visual acuities were improved two or more than two lines. 13 eyes of 12 patients were treated with the third surgical technique, resulting in graft ulceration in 4 patients and graft rejection in 4 patients with bad prognosis. CONCLUSIONS: The effect of unilateral ocular surface disease treated with limbal autograft transplantation is satisfactory. For bilateral ocular surface disease, the method of limbal allograft transplantation should be improved to resolve some problems such as graft rejection.

Adolescent↗

PubMed2000

[The study of facial neurapraxia].

OBJECTIVE: To study the clinical characteristics and mechanism of facial neurapraxia. METHOD: Patients were tested with nerve excitability method and judged the degree of facial paralysis. Animal mode of neurapraxia was made and threshold of evoked electromyographic potential was tested. The fibers of facial nerve were observed under transmission electromicroscope. RESULT: Average restoration time of evoked electromyographic potential was 52.5 min. The lamellar separation of myelin sheath of facial nerve was found under electromicroscope. Patients with facial neurapraxia was judged as denervation negative and residual function of facial muscles was above 65%. CONCLUSION: Facial neurapraxia is mild reversible facial paralysis and relevant to the lamellar separation.

Animals↗

PubMed2000

[Morphological and commercial identification on semen torreyae].

The morphological characters and commercial identification on Semen Torreyae has been reported. The results of identification of commercial samples indicated that Torreya grandis was mainly used; T. fargesii, T. yunnanensis and T. jackii were used in their producing areas.

Pharmacognosy↗

PubMed2000

[Determination of amino acids in seeds of genus Torreya in China].

OBJECTIVE: To determine the contents and analyze the ingredients of the amino acids in seeds of genus Torreya. METHODS: The amino acid contents and ingredients were determined by amino acid analyzer. RESULTS: There were 19 amino acids in the seeds of T. grandis, T. grandis cv. merrillii, T. yunnanensis, T. jackii and T. fargesii, and their amino acid contents are 9.10%, 9.90%, 5.03%, 7.26% and 6.07% respectively. There were 17 amino acids in the seeds of T. jiulongshanensis, T. nucifera and T. grandis cv. merrillii (baked) and their amino acid contents are 14.11%, 9.87% and 9.22% respectively. tively.

Amino Acids↗

PubMed2000

[Multiple types of chemokines expressed in mouse thymic stromal cell lines].

OBJECTIVE: To investigate semi-quantitative mRNA expression of SDF-1 alpha, IP-10, KC, MCP-1, and RANTES in thymic stromal cell lines of MTEC1, MTDC, D2SC, MTECB, TEC 1C8, TNC as well as in the primary thymic stromal cell cultures. The chemotactic activities of recombinant SDF-1 alpha, IP-10, MCP-1, and RANTES to mouse thymocytes were detected. METHODS: Using beta-actin as internal control, the mRNA of the chemokines listed above were amplified for 30 cycles with RT-PCR. The amplified products were observed by agarose electrophoresis, and each band was analyzed with integrated optical density. With the method of Boyden chamber assay, the chemotactic activities of recombinant SDF-1 alpha, IP-10, MCP-1, and RANTES were detected to thymocytes, and the chemotactic indices were calculated. RESULTS: The expression intensity of SDF-1 alpha, IP-10, KC, MCP-1, and RANTES varied from each other in the stromal cell lines detected. The PCR products of SDF-1 alpha and MCP-1 were not seen in D2SC or TEC 1C8, nor was the band of KC observed in TEC 1C8 either. The chemotactic indices of recombinant SDF-1 alpha, IP-10, MCP-1, and RANTES to thymocytes were 3.7, 4.5, 6.2, and 2.6, respectively. CONCLUSIONS: Different thymic stromal cell lines could express different types of chemokines with different expression intensities. To thymocytes, recombinant SDF-1 alpha, MCP-1, and IP-10 showed strong chemotactic activities, while the chemotactic activity of RANTES was very weak.

Animals↗

PubMed1999

Anti-AIDS agents. 37. Synthesis and structure-activity relationships of (3'R,4'R)-(+)-cis-khellactone derivatives as novel potent anti-HIV agents.

To explore the structural requirements of (+)-cis-khellactone derivatives as novel anti-HIV agents, 24 monosubstituted 3', 4'-di-O-(S)-camphanoyl-(+)-cis-khellactone (DCK) derivatives were synthesized asymmetrically. These compounds included 4 isomeric monomethoxy analogues (3-6), 4 isomeric monomethyl analogues (7-10), 4 4-alkyl/aryl-substituted analogues (11-14), and 12 4-methyl-(+)-cis-khellactone derivatives (15-26) with varying 3', 4'-substituents. These (+)-cis-khellactone derivatives were screened against HIV-1 replication in acutely infected H9 lymphocytes. The results demonstrated that the (3'R,4'R)-(+)-cis-khellactone skeleton, two (S)-(-)-camphanoyl groups at the 3'- and 4'-positions, and a methyl group on the coumarin ring, except at the 6-position, were optimal structural moieties for anti-HIV activity. 3-Methyl- (7), 4-methyl- (8), and 5-methyl- (9) 3',4'-di-O-(S)-camphanoyl-(3'R, 4'R)-(+)-cis-khellactone showed EC(50) and therapeutic index values of <5.25 x 10(-5) microM and >2.15 x 10(6), respectively, in H9 lymphocytes, which are much better than those of DCK and AZT in the same assay. Furthermore, 8 and 9 also showed potent inhibitory activity against HIV-1 replication in the CEM-SS cell line, and most monosubstituted DCK analogues were less toxic than DCK in both assays.

Anti-HIV Agents↗

PubMed1999

Transient kinetic analysis of N-phenylmaleimide-reacted myosin subfragment-1.

Alkylation of myosin's Cys-707 (SH1) and Cys-697 (SH2) has profound consequences for myosin's ability to interact with actin and hydrolyze MgATP. Pre-steady-state measurements of myosin-S1 alkylated at SH1 and SH2 by N-phenylmaleimide (NPM) in the presence of ATP were taken to identify the steps of the reaction that are altered. It was found that the rate constant most affected by this modification is the apparent rate of the ATP hydrolysis step. This rate constant is reduced 20000-fold, an effect comparable in magnitude to the effect of the same modification on the binding of MgATP to S1 or acto-S1 [Xie, L., and Schoenberg, M. (1998) Biochemistry 37, 8048]. In contrast, the rate constants of phosphate release and dissociation of acto-S1 by ATP were reduced <20-fold. For unmodified S1, the enhancement of fluorescence seen after addition of ATP had the same rate constant as the ATP hydrolysis step (S1.ATP if S1.ADP.Pi) measured by single-turnover experiments in a quench-flow experiment. This is consistent with results previously observed [Johnson, K. A., and Taylor, E. W. (1978) Biochemistry 17, 3432]. However, NPM-modified S1 exhibited virtually no fluorescence enhancement upon ATP binding. This provides further evidence that M.ATP is the predominant intermediate of NPM-S1-catalyzed ATP hydrolysis.

Actins↗

PubMed1999

Identification and characterization of receptor for mammalian hepatopoietin that is homologous to yeast ERV1.

Hepatopoietin (HPO) is a novel polypeptide mitogen specific for hepatocytes and hepatoma cell lines, which is derived from liver and supports its regeneration. To determine whether HPO acts via a receptor-based signal transduction, recombinant human hepatopoietin was labeled by iodination and used to characterize its binding activity by specific displacement test and Scatchard analysis in primarily cultured rat hepatocytes and human hepatoma Hep-G2 cells. The binding was saturable and specific because it was replaceable by HPO but not by epidermal growth factor, transforming growth factor-alpha, or insulin. Scatchard analysis indicated the presence of a single class of high affinity receptor with dissociation constant (Kd) of 2 and 0.7 pM, and a receptor density of about 10, 000 sites/cell and 55,000 sites/cell in the rat hepatocytes and human hepatoma cells, respectively. The Kd values were consistent with the half-maximum dose of HPO activity. Affinity cross-linking of the receptor with 125I-HPO revealed a polypeptide of molecular mass approximately 90 kDa by SDS-polyacrylamide gel electrophoresis. Thus, the molecular mass of the HPO receptor was calculated to be about 75 kDa. These data demonstrated the existence of an HPO receptor in hepatocytes and hepatoma cells, which may account for biological effect.

Animals↗

PubMed1999

The use of laser scanning cytometry to assess depth of penetration of adenovirus p53 gene therapy in human xenograft biopsies.

SCH58500 is an agent for gene therapy of cancer, consisting of a replication-deficient type 5 adenovirus (Ad5) expressing the human p53 tumor suppressor gene (Ad5/p53). An important question about the use of Ad5/p53 gene therapy is how to achieve the therapeutically effective delivery of an Ad5/p53 vector to the tumor. We wanted to determine the effective depth of penetration of an Ad5/p53 vector by dosing the vector in an experimental human xenograft/SCID model. To assess depth of penetration, we developed a novel methodology for scanning tissue sections by laser scanning cytometry (LSC). SCID mice were given intraperitoneal injections of either p53(null) SK-OV-3 human ovarian tumor cells or p53(mut) DU-145 human prostate tumor cells to establish xenograft solid tumors. Mice were then dosed once or twice at 24-hour intervals by intraperitoneal injection with SCH58500 (Ad5/p53), an adenovirus construct expressing beta-galactosidase (Ad5/beta-gal), or a buffer control. Additional groups of mice received a single intraperitoneal dose of 10 mg/kg paclitaxel either alone or coadministered with Ad5/p53. Twenty-four hours after each last dose, the human solid tumor xenograft and relevant mouse tissue were removed from each mouse for the analysis of Ad5/p53 penetration. Immunohistochemistry (IHC) for beta-galactosidase protein revealed a depth of penetration of between 1 and 10 cells from the tumor surface. In some mice, hepatocytes in the periportal regions of liver lobules were also positive, indicating systemic absorption of adenovirus from the peritoneal cavity. IHC staining for p53 and p21 proteins in SK-OV-3 solid tumor xenografts revealed similar Ad/p53 penetration. LSC was used to map and quantitate apoptosis in both tumor and liver tissue biopsies, with over 450,000 nuclei from liver tissue and 150,000 nuclei from tumor tissue being evaluated. LSC analysis demonstrated a high level of apoptosis in the tumors that had been removed from Ad5/p53-dosed mice (12.7-19.7%). This level of apoptosis was significantly higher (P < 0.05) than was observed for liver tissues taken from Ad5/p53-dosed mice (2.7-8.0%) or tumor tissues taken from either Ad5/beta-gal-dosed mice (3.0-6.4%) or buffer control-dosed mice (3.0-5.3%). Scan bit maps from the extensive LSC analyses confirmed that apoptosis was present to about the same depth (1-10 cells) as had been identified by IHC for beta-galactosidase, p53, and p21 proteins. Paclitaxel coadministered with Ad5/p53 had no effect on Ad5 penetration into solid tumors in vivo as measured by IHC for p53 or p21 protein. However, the combination therapy did cause an elevation in the number of tumor cells undergoing apoptosis.

Adenoviridae↗

PubMed1999

Intravenous delivery of an endostatin gene complexed in cationic lipid inhibits systemic angiogenesis and tumor growth in murine models.

Inhibition of the neovascularization of tumors has proven efficacious in reducing tumor growth and metastases. Attaining antiangiogenesis through cationic lipid-based systemic gene therapy presents an attractive approach to the treatment of disseminated and primary cancers. Intravenous administration of an endostatin plasmid, complexed with a cationic lipid system, produced significant levels of endostatin in the lung and the circulation. The expressed endostatin blocked systemic angiogenesis and inhibited tumor growth in murine models. Cytokine induction by cationic lipid/DNA complex increased the anti-tumor activities of endostatin. These results demonstrate the possibility of using cationic lipid delivery of an antiangiogenic gene for cancer treatment.

Journal Article↗

PubMed1999

Hypertension is associated with a high risk of cancer.

To investigate the possible relationship between hypertension and cancer, a retrospective analysis was carried out using a database including 1225 cases, of which 552 were hypertensives and 673 normotensives. Seventy cases of cancers with different origins were found during a 17-year follow-up. Odds ratio (OR) for occurrence of cancer was calculated. It was shown that an age over 40 years, male sex, alcohol-taking, systolic and diastolic blood pressures (SBP/DBP) were the five risk factors for the occurrence of cancers, while occupation, smoking, body mass index, left ventricular hypertrophy, and antihypertensive medication had no effect on cancer incidence. Hypertensives were at a high risk of overall cancer incidence with OR 2.2 (P < 0.01). After stratification of age, OR for hypertensives aged 40-49 years old with SBP > or =140 mm Hg or DBP > or =90mm Hg was 3.18 and 2.98 (P < 0.01 respectively). The OR of cancer for non-alcohol taking male hypertensives with SBP < or =140 mm Hg or DBP > or =90 mm Hg were 3.6 (95%CI 1.37-9.68, P = 0.003) and 5.67 (95%CI 2.01-16.75, P < 0.001), 7.55 (95%CI 2.10-33.19, P < 0.001) and 7.80 (95%CI 2.14-33.79, P < 0.001) for non-alcohol taking female hypertensives with SBP > or =140 mm Hg or DBP > or =90 mm Hg. After adjustment of age, sex and alcohol taking, the OR of the cancer incidence was 3.45 (95%CI 1.30-9.01, P < 0.01) for male and 5.0 (95%CI 1.56-16.67, P < 0.01) for female hypertensives aged 40-49 years. Multiple logistic regression analysis shows that age over 40 years, male sex, alcohol-taking, and DBP were the four independent risk factors for cancers. It is concluded that hypertension is associated with a high risk of cancer.

Adult↗

PubMed1999

Effects of genistein and daidzein on membrane characteristics of HCT cells.

Genistein and daidzein are two major isoflavonoids in soybeans. They have received increasing attention because of their possible role in cancer prevention. In the present investigation, the human colon tumor (HCT) cell line was used to investigate the effect of isoflavonoids on cell growth with 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide colorimetric assay. We found that genistein and/or daidzein could inhibit growth in HCT cells. The 50% inhibitory concentrations of genistein and daidzein were 15 and 40 microM, respectively. Fluorescent polarization, quasielastic light scattering, and circular dichroism were used to study the influence of isoflavonoids on membrane characteristics of HCT cells, including membrane fluidity, density of cell surface charge, and membrane protein conformation. Membrane fluidity of HCT cells was obviously reduced by genistein, but not by daidzein. The effect of genistein was time and dose dependent. In addition, genistein and daidzein could reduce the density of cell surface charge and increase the order of membrane protein conformation. All these changes may represent one of the mechanisms of the effect of isoflavonoids on growth inhibition, differentiation promotion, and transfer interference in a tumor cell line.

Anticarcinogenic Agents↗

PubMed1999

An analysis of breastfeeding patterns and menses returning in Chengdu, China.

OBJECTIVE: To study the relationship between infant feeding practices and the duration of lactational amenorrhea, WHO conducted a multi-centered prospective study in 7 countries from 1989. This paper reports the preliminary results based on the data collected in Chengdu center in China. METHODS: A detailed follow-up survey was conducted among 541 pairs of mothers and infants from delivery to the returning of menses of mothers at the interval of every 2 weeks. RESULTS: The results showed that the mean number of breastfeeding episodes and mean duration of breastfeeds had little correlation with the time since delivery. Within 6 months since delivery, the percentage of infants' feeds consisting of breastmilk was over 90%, and this percentage dropped to 70% at 1 year's age of infants. The time to the start of regular supplementation was 153 days postpartum. The proportion of women in exclusive breastfeeding at 2 weeks postpartum was 73.4%, and these figures at 3 and 6 months postpartum were about 60% and 40%, respectively. Until 18 months postpartum, nearly 80% mothers were partial breastfeeding their infants. The cumulative probabilities of menses returning were 0.0150, 0.0395, 0.2345 and 0.6820 at 61, 89, 187 and 369 days postpartum respectively. The median duration of lactational amenorrhea was 282 days. CONCLUSION: These results indicated that the duration of lactational amenorrhea would be prolonged if the time of exclusive/predominant breastfeed was extended and the supplementary food was introduced later. The paper concluded that the first menses returning was the signal for initiating contraceptive methods for women.

Adult↗