Biomedical subjects

X Tian

Publications and source records attributed to X Tian.

At least 91 records · Page 5Linked to original sources

PubMed1998

Effects of spin labeled derivatives of podophyllotoxin on cell cycle and macromolecular synthesis in human lymphoid leukemia Molt 4B cells.

AIM: To examine the effect of the spin labeled derivatives of podophyllotoxin, N-podophyllic acid-N"-[4-(2,2,6,6-tetramethyl-1-piperidinyloxy)] thiosemicarbazide (GP4) and 4-[4"-(2",2",6",6"-tetramethyl-1"-piperidinyloxy) amino]-4'-demethylepipodophyllotoxin (GP7) on the cell cycle and macromolecular synthesis of human lymphoid leukemia Molt 4B cells in vitro. METHODS: MTT assay, 3H incorporation, and flow cytometer were used. RESULTS: GP4, GP7, and etoposide 0.02-100 mmol.L-1 cultured for 48 h inhibited the proliferation of human lymphoid leukemia Molt 4B cells. IC50 values of GP4, GP7, and etoposide were 0.11, 4.7, and 1.6 mmol.L-1, respectively. DNA and protein syntheses were obviously suppressed by GP4, GP7, and etoposide 10 mmol.L-1 for 48 h. After Molt 4B cells were treated with GP4, GP7, and etoposide 10 mmol.L-1 for 6 and 12 h, the mitotic index was increased by GP4 and reduced by GP7 and etoposide. According to flow cytometric BrdU/DNA analysis, GP4 slightly retarded S phase and mainly arrested cell cycle progression in G2/M phase, whereas GP7 similar to etoposide induced cells accumulated at S phase and retarded the cells in G2 phase. CONCLUSION: GP4 and GP7 inhibit the proliferation of Molt 4B cells, but the mechanisms are different.

Antineoplastic Agents, Phytogenic↗

PubMed1998

[A study on the relationship between serum anticardiolipin antibody and embryo implantation in an in vitro fertilization and embryo transfer program].

OBJECTIVE: To study the role of serum anticardiolipin antibody in embryo implantation in an in-vitro fertilization and embryo transfer program. METHODS: 150 in vitro fertilization and embryo transfer (IVF-ET) treatment cycles from Nov. 1994 to May, 1996 were studied. Serum anticardiolipin antibody was measured by enzyme-linked immunosorbent assay (ELISA), and the clinical pregnancy outcome observed. RESULTS: Lower pregnancy rate 9.5% was found in 21 cycles of anticardiolipin antibody seropositive women compared with 26.3% in 129 cycles of anticardiolipin antibody seronegative women (P < 0.05). Patients with biochemical pregnancy and no pregnancy had seropositive anticardiolipin antibody in 20.0% and 16.2% compared with 5.6% in the patients with clinical pregnancy (P < 0.05). CONCLUSIONS: Failure of embryo implantation is associated with many factors. Our study demonstrated the serum anticardiolipin antibody in patients may play a part in embryo implantation and very early postimplantation loss.

Antibodies, Anticardiolipin↗

PubMed1998

[The role of decidua tissue lymphocytes in early pregnancy].

OBJECTIVE: To investigate the role of lymphocytes in early pregnancy decidua tissue. METHODS: Immunohistochemical and in situ hybridization techniques were employed to demonstrate the population, phenotype and mediator of lymphocytes in early pregnancy decidua. RESULTS: In early pregnancy decidua, CD8+ suppressor/cytotoxic T lymphocytes were very few. CD4+ helper lymphocytes were few and CD56+ lymphocytes (also named NK-like cell) were abundant. CD56+ lymphocytes containing perforin protein and expressing perforin mRNA were observed. CONCLUSIONS: The lymphocytes in early pregnancy decidua are specific and may play an important role in early pregnancy. They probably exert some positive influence on embryo implantation and placental development, and maintain the balance between trophoblastic cells and decidua tissue.

Adult↗

PubMed1998

[The study of autoantibodies in women with habitual abortion of unknown etiology].

OBJECTIVE: To evaluate the relationship between habitual abortion of unknown etiology and autoantibodies. METHODS: IgG and IgA antibodies against cardiolipin, specific antinuclear double-stranded DNA and single-stranded DNA were measured by enzyme linked immunosorbent assay (ELISA). Antinuclear antibody, smooth muscle antibody, antimitochondrial antibody and antiheart muscle antibody were performed by indirect immunofluorescence assay. Antiextractable nuclear antigen's antibodies were determined by immunodiffusion assay. RESULTS: Most women with habitual abortion of unknown etiology showed higher incidence of antibodies to cardiolipin, nuclear, smooth muscle compared with normal multigravida control (P < 0.05). CONCLUSIONS: These results indicate that most women with habitual abortion of unknown etiology have a higher level of autoreactivity, which may affect the course of pregnancy. The incidence of antismooth muscle antibody in women with habitual abortion of unknown etiology is also increased compared with normal multigravida control.

Abortion, Habitual↗

PubMed1998

[Perforin protein and gene expression in the different phases of endometrium].

OBJECTIVE: To study the expression of perforin protein and gene in the different phases of endometrium and the role of perforin in the reproductive system. METHODS: Immunohistochemical and in situ hybridization techniques were employed to demonstrate the population, phenotype of the perforin positive cell in endometrum of different phases of menstrual cycle, first-trimester decidua and postmenopausal endometrium. RESULTS: Perforin positive cells were found to be located in the endometrial stroma and expressed natural killer-like cell surface marker (CD56 antigen, also named NK-like cell or CD56+ lymphocyte). The quantitative analysis of perforin protein cells demonstrated an increase in number from proliferative endometrium to secretory endometrium through first-trimester decidua (P < 0.05). These cells were absent in the postmenopausal endometrium. Perforin mRNA positive cells formed islands in proliferative endometrium stroma, but the perforin protein expression cells were scattered. There was difference between the perforin gene expression and protein expression in proliferative endometrium. In first-trimester decidua, perforin mRNA positive cells incresed. Some perforin mRNA positive cells located around spiral arterioles were observed. CONCLUSIONS: Expression of perforin in the different phases of endometrium is specific and plays an important role in the reproductive function. They probably exert some influence on embryo implantation and may be involved in endometrial stromal breakdown during menstruation.

Adult↗

PubMed1998

[The study on the relationship between luteal phase serum sex hormone levels and pregnancy outcome in in vitro fertilization embryo transfer cycle].

OBJECTIVE: To study the influence of maternal endocrine factors on clinical pregnancy outcome in an in Vitro Fertilization Embryo Transfer (IVF-ET) program. METHODS: 62 IVF-ET treatment cylces were studied. Luteal phase serum sex hormone levels [estrogen (E2), progesterone (P), prolactin (PRL)] in natural and superovulation cycles were measured by radioimmunoassay and the clinical pregnancy outcome was observed. RESULTS: Serum luteal phase sex hormone levels were higher than in natural cycles (P < 0.05). P level and P/E2 ratio in progesterone supplementation group were higher than the group without progesterone supplementation (P < 0.05). In pregnancy group serum E2(4,885.5 +/- 1,269.0 pmol/L) was lower, PRL (66.4 +/- 26.8 micrograms/L), P/E2 (373.0 +/- 152.5) were higher than in nonpregnancy group (E2 6,091.2 +/- 1,522.1 pmol/L, PRL 49.1 +/- 24.1 micrograms/L, P/E2 227.4 +/- 116.7) (P < 0.05). When P/E2 ratio was between 300-400 and PRL level was between 60-100 micrograms/L, the clinical pregnancy rate increased markedly (P < 0.05). CONCLUSION: Luteal phase serum sex hormone level may influence embryo implantation in IVF-ET. In order to improve the clinical pregnancy rate, it is very necessary to supplement progesterone for the IVF-ET patients according to the different sex hormone levels.

Embryo Transfer↗

PubMed1998

[The effect of antisense epidermal growth factor receptor RNA on the growth of human malignant glioma cells].

OBJECTIVE: To study the effect of antisense EGFR RNA on the growth of human malignant glioma cells. METHODS: An antisense EGFR expression vector was constructed and introduced into human malignant glioma cells. PCR analysis was used to determine which clones were successfully transfected with antisense EGFR constructs. Western blotting analysis was used to determine EGFR protein level in the transfected cells. The in vitro growth and their ability to grow in soft agar were studied. RESULTS: Western blotting analysis showed six clones stably expressing lower levels of EGFR protein. Antisense EGFR RNA was found to inhibit the proliferation of human malignant glioma cells and their ability to grow in soft agar. There was a negative correlation between the growth inhibiting effect of antisense EGFR and EGFR protein expression. CONCLUSION: These results demonstrate that EGFR play an pivotal role in human malignant glioma cell growth. Antisense EGFR can inhibit the growth of human malignant glioma cells.

Cell Division↗

PubMed1998

[Changes in the contents of membrane phospholipid and membrane phospholipid asymmetry in glucose-6-phosphate dehydrogenase deficient erythrocyte].

OBJECTIVE: To study the effect of G6PD deficiency on membrane phospholipid structures. METHODS: Treatment of intact erythrocyte with phospholipase A2 was used for the membrane phospholipid asymmetry. Membrane phospholipid was determined by high performance liquid chromatography (HPLC). RESULTS: The contents of phosphatidylethanolamine (PE), phosphatidylcholine (PC), phosphatidylserine (PS) were 5.18 +/- 1.86, 1.51 +/- 0.58 and 5.70 +/- 1.91 mg/mg membrane protein, respectively, in G6PD deficient erythrocytes and were 5.59 +/- 1.16, 2.92 +/- 0.50 and 6.64 +/- 0.92 mg/mg membrane protein, respectively, in normal erythrocytes. In normal erythrocytes, 17.6% +/- 2.5% PE and 57.9% +/- 4.7% PC were present and no PS was found on the outer leaflet of the membrane. While in G6PD deficient ones, 30.2% +/- 5.7% PE, 53.8% +/- 7.4% PC and 27.2% +/- 5.8% PS were present on the outer leaflet. CONCLUSION: Membrane phospholipid changes in G6PD deficient erythrocytes might be one of the factors causing hemolysis.

Erythrocyte Membrane↗

PubMed1998

[Complex surgical therapy for severe hepatic trauma].

OBJECTIVE: To improve the result of surgical therapy for patients with severe hepatic injury. METHODS: Retrospective analysis was made on the result of surgical treatment of 237 patients with hepatic trauma during the past 8 years. 180 patients underwent surgery. Procedures such as packing with the omentum for the laceration of hepatic parenchyma, debridement or irregular hepatectomy under the direct control of lacerated hepatic blood vessels or Pringle's maneuvre and selective ligation of hepatic artery were used for patients with severe hepatic injury (Grad III-V). RESULTS: Among the 180 patients, 154 were cured, and 8 of 23 with posthepatic IVC injury were cured with the maximum blood transfusion of 12,000 ml. The overall morality rate was 11.8%(28 of 237 patients). Besides associated injuries inside and outside the abdomen, exsanguination with or without coagulopathy was the main cause of death. CONCLUSION: Accurate liver packing with appropriate adjunctive procedures is effective in the treatment of retrohepatic venous injury.

Adolescent↗

PubMed1998

[A randomized control clinical trial of glaucoma filtering surgery with homoharringtonine].

OBJECTIVE: To study the antiproliferative effects of homoharringtonine (Hh) on glaucoma filtering surgery. METHODS: In a randomized control clinical trial, 78 patients (88 eyes) with refractory glaucoma underwent trabeculectomy with and without Hh. In the Hh-treated eyes (n = 46), the therapeutic dose of Hh was: intraoperative application of Hh 0.4 mg and postoperative subconjunctival injections of Hh 0.62 +/- 0.20 mg (ranged 0.53 - 0.75 mg). In the control eyes (n = 42), Hh was not used. The follow-up period was 18 to 48 months, and the data were analyzed by using the life-table method of Kaplan-Meier. RESULTS: The cumulative success probability in Hh group was 84.5% and that in control group was 50.9%, the difference being significant (P < 0.05). The cumulative percentage of functioning bleb in Hh group was 84.2% and that in control group was 52.9% (P < 0.05). The rates of corneal erosion were 23.9% and 7.1%, and the rates of conjunctival wound leak were 6.5% and 2.4% in Hh and control group respectively. There was no significant change in corneal endothelial density following the use of Hh (P > 0.05). CONCLUSION: The study indicates that Hh is a safe and effective antiproliferative agent for the use in glaucoma filtering surgery, it not only can increase the success probability considerably, but also maintain at least the postoperative IOP at relatively low normal level for 3 years.

Adult↗

PubMed1998

[Synthesis and antitumor activity of new heterocyclic 5-fluorouracil derivatives].

Two new compounds I and II of 5-FU derivatives have been synthesized. The structures of the new compounds were confirmed by 1HNMR, MS, IR, UV and elemental analysis. The antitumor activities of compound I was tested against KB, HCT-8 and A2780. The preliminary results showed that the activity of compound I was stronger than that of HCFU and 5-FU.

Antimetabolites, Antineoplastic↗

PubMed1998

Ultrastructural observation on spermatocytogenesis in Taeniid cestodes.

AIM: To study the spermatocytogenesis of taeniid cestodes at the ultrastructural leaves. METHODS: Transmission electron microscopy. RESULTS: The ultrastructural observation on spermatocytogenesis in Taenia solium, T. saginata and T. pisiformis were made by TEM. Two types of spermatogonia; type A and B, as well as the supporting cells surrounding the peripheral of spermatogonia are recognized. The type A spermatogonia are stem cells and the type B are mother cells which produce 16 primary spermatocytes by mitosis for 4 times with the cells unseparated. The primary spermatocytes are characterized by the ribosome masses in the cytoplasm. 32 secondary spermatocytes arranged in roselike were produced by reductive division of primary spermatocytes. The secondary spermatocytes become the spermatid quickly by short time development. CONCLUSION: The dividing mode of spermatogonia in Taeniid cestodes is mitosis with cells unseparated.

Animals↗

PubMed1998

Ultrastructural observation on the transformation of the spermatozoon in spermatogenesis of Taeniid cestodes.

AIM: To study the transformation of taeniid spermatozoon during spermatogenesis on the ultrastructure level. METHODS: Transmission electronmicroscopy. RESULTS: This paper was the second part of the ultrastructural observations on the spermatogenesis in Taeniid cestodes: The transformation of the spermatozoon. The 64-spermatid-plasmodium was generated from the secondary meiosis of the 32 rose-like secondary spermatocytes. The transformation of the spermatozoon was a complex process. Firstly, both the cytoplasm and nucleus of the spermatid elongated while the cytoplasm increased and connected to the cytoplasmic mass (cytophore). Secondly, the chromatins of nucleus polymerized to a thread-bundle-like structure. Finally, it detached from the cytoplasm mass and became a mature spermatozoon. The mature spermatozoon was a thread-like structure, about 16.2-18.6 microns in length and 0.35-0.45 micron in diameter. There were two structurally distinct parts: the part with the nucleus was the head and the part without the nucleus was the tail. The head measured about 5-6 microns in length, 1/3 of the total body length and contained an elongated nucleus which twined around the axoneme without mitochondria. The tail was about 11.2-16.6 microns in length. Throughout the core of the tail was an axoneme with typical "9 + 1" structure. The anterior of the tail, just behind the head, were some mitochondria, about 1.6-1.7 microns in total length which twined around the axoneme. The posterior of the tail contained only an axoneme. In cross-section of the spermatozoon, about 46 microtubules were beneath the plasma membrane. CONCLUSION: The transformation of the spermatozoon is a very complex process.

Animals↗

PubMed1998

Ultrastructural observations on the formation and metabolism of calcareous corpuscles in Cysticercus cellulosae.

AIM: To study the formation and metabolism of calcareous corpuscles from Cysticercus cellulosae at the ultrastructure level. METHODS: Transmission electron microscopy. RESULTS: The developmental processes of calcareous corpuscles could be divided into two stages: the intracellular formation stage and the extracellular metabolic stage. The calcareous corpuscles were formed in a cell which we named calcareous corpuscle forming cell. At the early stage of the formation, the corpuscles appeared to be secretory granules in the cells. With the development of the corpuscles, they became bead-shaped and lamellae-like, then the calcareous corpuscle forming cell enlarged and the organellae degenerated. Finally the corpuscles gathered to form particle substances with black dense background, while the nucleus and organellae of the forming cell all disappeared. There were 1-3 or 10-20 calcareous corpuscles in a mature forming cell. Then, the corpuscles were released to the parenchymal tissues and gradually appeared to be concentric lamella or an empty cavity during the metabolic process. CONCLUSION: The calcareous corpuscles were formed in calcareous corpuscle forming cell and consumed in metabolic process in the parenchymal layer of Cysticercus cellulosae.

Animals↗

PubMed1998

[Purification and properties of alkaline cellulase from alkalophilic Bacillus N6-27].

The alkaline cellulase produced by alkalophilic Bacillus sp. N6-27 was purified to electrophoresis homogeneity by (NH4)2SO4 fractionation, Sepharose CL-4B hydrophobic interaction chromatography, Bio-gel P-150 chromatography. The molecular weight and pI determined by SDS-PAGE and by PAGE-IEF were 94,000 and 4.2, respectively. The optimum temperature and pH for the enzymatic catalysis were 55 degrees C and 8.5, respectively. The enzyme activity was stable under 50 degrees C and in the pH range of 6-11. The substrate was carboxymethylcellulose (CMC). The enzyme activity was strongly inhibited by Fe2+, Cu2+ and Hg2+.

Bacillus↗

PubMed1998

The dynamic regulation of myocardial oxidative phosphorylation: analysis of the response time of oxygen consumption.

Although usually steady-state fluxes and metabolite levels are assessed for the study of metabolic regulation, much can be learned from studying the transient response during quick changes of an input to the system. To this end we study the transient response of O2 consumption in the heart during steps in heart rate. The time course is characterized by the mean response time of O2 consumption which is the first statistical moment of the impulse response function of the system (for mono-exponential responses equal to the time constant). The time course of O2 uptake during quick changes is measured with O2 electrodes in the arterial perfusate and venous effluent of the heart, but the venous signal is delayed with respect to O2 consumption in the mitochondria due to O2 diffusion and vascular transport. We correct for this transport delay by using the mass balance of O2, with all terms (e.g. O2 consumption and vascular O2 transport) taken as function of time. Integration of this mass balance over the duration of the response yields a relation between the mean transit time for O2 and changes in cardiac O2 content. Experimental data on the response times of venous [O2] during step changes in arterial [O2] or in perfusion flow are used to calculate the transport time between mitochondria and the venous O2 electrode. By subtracting the transport time from the response time measured in the venous outflow the mean response time of mitochondrial O2 consumption (tmito) to the step in heart rate is obtained. In isolated rabbit heart we found that tmito to heart rate steps is 4-12 s at 37 degrees C. This means that oxidative phosphorylation responds to changing ATP hydrolysis with some delay, so that the phosphocreatine levels in the heart must be decreased, at least in the early stages after an increase in cardiac ATP hydrolysis. Changes in ADP and inorganic phosphate (Pi) thus play a role in regulating the dynamic adaptation of oxidative phosphorylation, although most steady state NMR measurements in the heart had suggested that ADP and Pi do not change. Indeed, we found with 31P-NMR spectroscopy that phosphocreatine (PCr) and Pi change in the first seconds after a quick change in ATP hydrolysis, but remarkably they do this significantly faster (time constant approximately 2.5 s) than mitochondrial O2 consumption (time constant 12 s). Although it is quite likely that other factors besides ADP and Pi regulate cardiac oxidative phosphorylation, a fascinating alternative explanation is that the first changes in PCr measured with NMR spectroscopy took exclusively place in or near the myofibrils, and that a metabolic wave must then travel with some delay to the mitochondria to stimulate oxidative phosphorylation. The tmito slows with falling temperature, intracellular acidosis, and sometimes also during reperfusion following ischemia and with decreased mitochondrial aerobic capacity. In conclusion, the study of the dynamic adaptation of cardiac oxidative phosphorylation to demand using the mean response time of cardiac mitochondrial O2 consumption is a very valuable tool to investigate the regulation of cardiac mitochondrial energy metabolism in health and disease.

Adenosine Diphosphate↗

PubMed1997

Study of the interaction between novel ruthenium(II)-polypyridyl complexes and calf thymus DNA.

Four new complexes L2RuL'2+, where L = 2,2'-bipyridine (bpy) and 1,10-phenanthroline (phen), L' are Schiff bases or phenylhydrazones derived from 4,5-diazafluoren-9-one (AFO), were prepared. They were characterized by elemental analyses, absorption, IR, and emission spectra. The binding of these complexes to calf thymus DNA has been investigated by absorption, circular dichroism spectroscopy, and viscosity measurement. The experimental results show that the complexes bind to calf thymus DNA by three kinds of binding modes, respectively-electrostatic mode, nonintercalative binding mode, and intercalative binding mode.

2,2'-Dipyridyl↗

PubMed1997

Reduction of vesicular acetylcholine transporter mRNA in the rat septum following lead exposure.

We have previously observed that maternal exposure to lead (Pb) results in a reduction of levels of mRNA coding for cholineacetyltransferase (ChAT) in the septum of developing rat without affecting the dams. Here we report that Pb similarly affects the expression of vesicular acetylcholine transporter (VAChT) mRNA in the rat septum. In close agreement with the time course of ChAT mRNA expression, septal VAChT mRNA levels increased from 30% at postnatal day 7 to 78% and 100% of adult levels at days 14 and 21, respectively. Maternal exposure to 0.2% lead acetate in drinking water from gestational day 16 resulted in an approximately 30% reduction of VAChT in 7 and 21-day-old rat pups without affecting VAChT mRNA levels in the dams. These results indicate a developmental stage-dependent interference by Pb with ChAT/VAChT gene expression in the rat septum.

Acetylcholine↗