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Biomedical subjects

Y Tian

Publications and source records attributed to Y Tian.

At least 127 records · Page 7Linked to original sources
PubMed1998

Transcriptional suppression of estrogen receptor gene expression by 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD).

TCDD, the most potent congener of the polychlorinated dioxins, has been shown to be an antiestrogen. The mechanisms of TCDD-induced antiestrogenicity are still under investigation. In this study, we investigated the effects of TCDD on the expression of the estrogen receptor (ER) gene. We studied the levels of un-spliced ER transcript (hnRNA) as well as the ER mRNA in ovary, uterus and liver of TCDD-treated mice with different genetic backgrounds. To quantitate the ER hnRNA levels, the intron and exon boundary of ER hnRNA was amplified by competitive RT-PCR. The ER mRNA from these mice was quantitated by competitive RT-PCR amplifying exons separated by an intron. ER hnRNA and ER mRNA levels were quantitated 4 days after a single i.p. dose of TCDD (5 microg/kg) in female C57BL/6J (B6) mice, which carry the responsive allele to TCDD. TCDD treatment significantly (p < 0.05) suppressed the levels of ER hnRNA in the ovary (27.4%) and uterus (21.9%). The decreases in ER hnRNA were coordinated with significant (p < 0.01) decreases in ER mRNA in ovary (57.7%) and uterus (37.6%). There was a significant decrease (20.3%, p < 0.05) in liver ER mRNA, however, the changes of ER hnRNA in liver were not significant. The coordinated decreases in ER hnRNA and mRNA in TCDD-treated mice suggest a suppression of transcription of the ER gene. We performed the same study on DBA/2J (D2) mice, which possess the "non-responsive" allele of the aryl hydrocarbon receptor (AhR). These mice demonstrated no significant decrease in either the ER mRNA or hnRNA after TCDD treatment. Overall, these results suggest that TCDD suppresses the gene expression of the ER receptor by decreasing its transcription, and the AhR plays an important role in mediating this response.

Animals↗
PubMed1998

Semi-preparative separation and purification of taxol analogs by high-speed countercurrent chromatography.

High-speed countercurrent chromatography (HSCCC) was applied to the semi-preparative separation of taxol and its analogs, such as cephalomannine and 7-epi-10-deacetyltaxol from the extract of the bark of Taxus yunnannesis. The experiments were performed with a quaternary two-phase solvent system composed of n-hexane-thyl acetate-ethanol-water through two steps. In the first step, the four components were separated into two groups at a volume ratio of 1:1:1:1 and, in the second step, two components in each group were separated at different volume ratios of 3:3:2:3 or 4:4:3:4. The present method also allows consecutive injections with reproducible results. HPLC analysis showed that the purity of the four components obtained from a partially purified sample, containing taxol at 10%, ranged from 85 to 99%. The results indicated that HSCCC can be effectively used for the semi-preparative separation and purification of taxol and its analogs.

Antineoplastic Agents, Phytogenic↗
PubMed1998

Angiotensin II activates mitogen-activated protein kinase via protein kinase C and Ras/Raf-1 kinase in bovine adrenal glomerulosa cells.

Angiotensin II (Ang II) stimulates growth and mitogenesis in bovine adrenal glomerulosa cells, but little is known about the signaling pathways that mediate these responses. An analysis of the growth-promoting pathways in cultured bovine adrenal glomerulosa cells revealed that Ang II, acting via the AT1 receptor, caused rapid but transient activation of mitogen-activated protein kinase (MAPK), with an ED50 of 10-50 pM. Although neither Ca2+ influx nor Ca2+ release from intracellular stores was sufficient to activate MAPK, Ca2+ appeared to play a permissive role in this response. A major component of Ang II-induced MAPK activation was insensitive to pertussis toxin (PTX), although a minor PTX-sensitive component could not be excluded. Ang II also induced the rapid activation of ras and raf-1 kinase with time-courses that correlated with that of MAPK. Activation of protein kinase C (PKC) by phorbol 12-myristate 13-acetate was sufficient to activate both MAPK and raf-1 kinase. However, whereas PKC depletion had no effect on Ang II-induced raf-1 kinase activation, it attenuated Ang II-induced MAPK activation. Ang II also stimulated a mobility shift of raf-1, reflecting hyperphosphorylation of the kinase. However, unlike its activation, raf-1 hyperphosphorylation was dependent on PKC and its time-course correlated not with activation, but rather with deactivation of the kinase. Taken together, these findings indicate that Ang II stimulates multiple pathways to MAPK activation via PKC and ras/raf-1 kinase in bovine adrenal glomerulosa cells.

Angiotensin II↗
PubMed1998

Delayed neuropathy and inhibition of soluble neuropathy target esterase following the administration of organophosphorus compounds to hens.

Delayed neuropathy and inhibition of soluble neuropathy target esterase (NTE) and acetylcholinesterase (AChE) activities in different regions of brain and spinal cord of adult hens were studied after the intravenous administration of leptophos (30 mg/kg), tri-o-cresyl phosphate (TOCP 40 mg/kg) or dipterex (200 mg/kg). The level of NTE activity varied according to the regions of the central nervous system (CNS) of the control (normal) hen, being higher in the cerebrum (74.1 micromol of phenyl valerate hydrolyzed/10 minutes/mg protein) and in the cerebellum (68.7), and lower in the spinal cord (44.5 in cervical, 55.6 in thoracic and 50.0 in lumbar cord). Hens given leptophos and TOCP demonstrated delayed neuropathy with obvious inhibition of NTE, but the times of onset and the degrees of peak inhibition of NTE activity were different: 6-24 hours after dosing and 73-82% of normal activity for leptophos, and 24-48 hours and 45-80% for TOCP, respectively. Furthermore, the average inhibition of NTE during 6-48 hours after dosing, (called here 'period average inhibition') was also significantly different between the leptophos group (63-73%) and TOCP group (40-64%). Hens given dipterex did not demonstrate delayed neuropathy, and had the least peak inhibition and period average inhibition of NTE activity among the 3 groups. Ratios of NTE inhibition/AChE inhibition were higher in the leptophos group (0.91-1.24) and TOCP group (1.13-2.45) than in the dipterex group (0.25-0.79). These results indicate that the distribution of NTE in the soluble fraction of membrane proteins is different in different regions of the CNS, and that the degree of peak inhibition of NTE activity and the time of onset of peak inhibition induced by organophosphorus compounds (OPs) also differ for different OPs. Thus, practical and useful NTE measurements should identify the peak inhibition and period inhibition in several nervous tissue regions.

Acetylcholinesterase↗
PubMed1998

Pharmacokinetics and neurotoxicity of dipterex in hens. A comparative study of administration methods.

We compared the tissue concentration of dipterex and the inhibition of the neuropathy target esterase (NTE) activity among groups of hens (n = 8 each) which were intravenously (i.v.), subcutaneously (s.c.) or orally (p.o.) administered the insecticide dipterex. The tissue concentrations of dipterex in the s.c. group were higher than those in the i.v. and p.o. groups. When dosed subcutaneously, the tissue concentration of dipterex was high in the brain, spinal cord and muscle at 3 hr after dosing and then concentrated in the spinal cord and muscle for the subsequent 3 hr. When dosed intravenously or orally, dipterex was evenly dispersed in various tissues. All hens treated with dipterex showed acute neurotoxic signs within 15 min after dosing. The hens dosed intravenously recovered from this acute poisoning within 3 hr, and the hens dosed orally recovered within 6 hr, while the hens dosed subcutaneously recovered within 24 hr after dosing. One hen in the s.c. group exhibited acute neurological sequelae following the acute poisoning. In addition, the loss of body weight was the largest in the s.c. group (157 +/- 49 g), moderate in the i.v. group (133 +/- 91 g), small in the p.o. group (96 +/- 54 g) and the smallest in the PMSF (phenylmethanesulfonyl fluoride, which was dosed to promote delayed neuropathy) group (80 +/- 49 g). In the untreated hens, the activity of NTE in both the cerebrum and cerebellum was higher than that in the midbrain (p < 0.01). There was no difference in NTE activity between the cerebrum and cerebellum. In both the cerebrum and midbrain, the inhibition of NTE activity in the p.o. group was less than that in the i.v. and s.c. groups, and no difference was found between the i.v. and s.c. groups. In the cerebellum, the inhibition of NTE activity in the s.c. group was larger than that in the i.v. and p.o. groups. These results indicate that the s.c. dosing of dipterex results in a stronger neurotoxicity compared to i.v. and p.o. dosing. However, it was difficult to induce the clinical signs of delayed neuropathy with any administration of dipterex in hens, even when the promotion of delayed neurotoxicity of dipterex was attempted with PMSF or double doses of dipterex itself.

Administration, Oral↗
PubMed1998

Light-scattering method in particle size analysis of parenteral emulsions.

The use of a light-scattering particle size distribution analyzer has been shown to be a convenient method for characterizing the particle size distribution of parenteral emulsions. However, the concentrations of the samples used were found to have a major impact on the particle size distribution results, particularly for samples with a mean particle size smaller than 0.2 micron. An increase in sample concentration caused a shift to smaller particle sizes as a result of multiple scattering. The blue-light (tungsten lamp) intensity, instead of the He-Ne laser integrity, should be used to control sample concentration within the optimal range for measurement.

Emulsions↗
PubMed1998

Cloning of 1-aminocyclopropane-1-carboxylate (ACC) synthetase cDNA and the inhibition of fruit ripening by its antisense RNA in transgenic tomato plants.

A 1.7 kb fragment of ACC synthetase cDNA, one member of the ACC synthetase multigene family, was amplified from total tomato cDNA through a polymerase chain reaction (PCR) and cloned in E. coli. Restriction mapping and sequencing analysis confirmed its fidelity and correctness. The cloned ACC synthetase gene was then inserted into a binary vector pBin437, in an inverted orientation between the CaMV 35S promoter with duplicated enhancers and the Nos 3' transcriptional termination sequence, to construct an expression vector pBACC. Transgenic tomato plants were obtained by A. tumefaciens-mediated transformation of cotyledons. PCR detection and Southern blot analysis confirmed the integration of the antisense ACC synthetase gene in the transformed tomato genome. The results from RT-PCR of RNAs isolated from transgenic tomato leaves confirmed that antisense ACC synthetase RNA was synthesized in these transgenic plants. The amount of ethylene released from transgenic tomato fruits was reduced significantly to about 30% of that released by non-transformed controls. The inhibition effect of antisense RNA on fruit ripening was observed in transgenic plants and their progeny (T1). The shelf life of transgenic tomato fruits was at least 60 days at room temperature without significant change in hardness and color. After 15-20 days of treatment of the transgenic fruits with ethylene, most of them reached the ripe stage. The antisense ACC synthetase gene was inherited as a single gene in the progenies of transgenic tomatoes determined by T1 progeny analysis, consistent with the results of Southern blot analysis. Transgenic homozygotes expressing antisense ACC synthetase RNA showed prolonged shelf life in the T2 progeny.

Cloning, Molecular↗
PubMed1998

Cellular composition and anatomic distribution in nonfunctioning pancreatic endocrine tumors: immunohistochemical study of 30 cases.

OBJECTIVE: To investigate the cytological pattern and distribution in nonfunctioning pancreatic endocrine tumors. METHODS: Using labeled streptavidin-biotin (LSAB), immunohistochemical staining for insulin, glucagon, somatostatin, pancreatic polypeptide and gastrin was performed on 30 nonfunctioning pancreatic endocrine tumors from 30 patients. The cellular composition and anatomic distribution in these tumors were analyzed. RESULTS: Of 30 tumor tissues, 22 (73.3%) were found to contain cells immunoreactive to 1-4 kinds of peptide hormones; 17 (56.7%) showed positive staining for more than one peptide and up to 4 peptides; and 8 (26.7%) showed negative immunoreaction to all antiserum applied. No tumor was found to contain immunoreactive gastrin. Among 17 multihormonal tumors, 4 contained 2 kinds of peptide hormones, 8 had 3 kinds, and 5 harbored 4 kinds of peptide hormones. In addition, the difference in the number and type of positive endocrine cells between the tumors arising from the head of the pancreas and those arising from the body and tail of the pancreas were statistically significant (P < 0.05). CONCLUSIONS: Immunohistochemically, the high positive rate to peptide hormones suggests that the nonfunctioning pancreatic endocrine tumors are actually not nonfunctioning; they are asymptomatic pancreatic endocrine tumors. Moreover, an uneven distribution of positive endocrine cells in the nonfunctioning pancreas endocrine tumors within the pancreas was identified.

Adenoma, Islet Cell↗
PubMed1998

[Application of multi-tumor markers in ovarian carcinoma].

OBJECTIVE: To improve the specificity and sensitivity of diagnosis and to strengthen postoperative monitoring for patients with ovarian cancer. METHODS: Sera obtained from patients-ovarian epithelial carcinoma (67 cases), benign ovarian tumor (33 cases) and from donor (38 cases) as control. Serologic examination of 5 tumor markers--SA, LSA, CA125, CP2, and 6B11Ab2 was performed. RESULTS: The sensitivity and specificity in diagnosis of ovarian cancer were 83.6% and 85.9% respectively for CA125 alone (> 35 kU/L) whereas 86.6% and 94.4% respectively for multi-tumor markers combined in which 3 or more indices showed positive. In addition, serial measurements of multi-tumor markers have been done for 1 year after operation in 24 cases of ovarian epithelial carcinoma. The correlations between the levels of multi-tumor markers either and the results of second look operation or and clinical manifestation of recurrence were analyzed. CONCLUSION: Multi-tumor markers examination could improve the diagnosis of ovarian cancer and early detection of recurrence.

Biomarkers, Tumor↗
PubMed1998

[Protein status and antioxidant capability of residents in endemic and nonendemic areas of Keshan disease(KD)].

From a survey of residents in endemic and nonendemic areas of Keshan disease(KD), it was found that the plasma cystine, tryptophan and lysine as well as blood selenium content were lower, while the plasma lipid peroxide was higher in endemic areas than those in non-endemic areas. These results suggests that the selenium deficiency coexisting with cystine and tryptophan insufficiency decreases the antioxidant defense of the organism and may be one of the important factors for the development of KD. The role of sulfur-containing amino acid in antioxidant defense is discussed emphatically.

Adult↗
PubMed1998

[Determination of copper, iron and zinc in hair of mentally retarded children by oscillopolarography].

The oscillopolarographic method (proposed by Ding Jianwen)for the simulltaneous determination of copper, iron and zinc in hair was further studied and applied to the investigation of copper, iron, zinc content in hair samples from 46 mentally retarded children and 49 healthy children. For copper, iron, zinc, the detection limits were 0.03, 0.03, 0.01 microgram/ml, dynamic range 0.05-15, 0.05-2.5, 0.2-10 micrograms/ml, the RSD of sample analysis 3.2%, 3.3%, 2.4%, the recoveries 96: 0%-105.2%, 2%, 97.3%-109.0%, 94.7%-107.7%, respectively. The difference between the results for the same sample by this method and the atomic absorption spectroscopic method was no statistical significance. The results showed that the copper content and iron content of hair samples from mentally retarded children were significantly lower than those of healthy children.

Child↗
PubMed1998

[Effect of dietary selenium on the activities of glutathione peroxidase and deiodinase in rat liver].

In order to investigate the effect of dietary selenium on the activities of glutathione peroxidase and deiodinase and the least selenium requirement for their optimal activities, fifty four male weanling Wistar rats of 50-60g body weight were randomly divided into 9 groups and were fed with semisynthetic diets of different selenium level for 20 weeks. The selenium in the diets were 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.1, 0.2 and 5 mg/kg diet respectively. The body weight of ratsin the ninth group was different significantly from the seventh and eighth group, but those in the other eight groups were not significantly different. The activities of liver glutathione peroxidase in 0.1, 0.2 and 5 mg/kg groups were the highest among the nine groups. So at least 0.1 mg/kg diet is required for its normal activity. The activities of the liver type I deiodinase of nine groups were high from 0.05 to 0.2 mg/kg diet groups and at least Se 0.05 mg/kg diet is required for its normal activity.

Animals↗
PubMed1998

[Study on relationship between detection of interleukin-6 and its mRNA and pregnancy induced hypertension].

OBJECTIVE: To investigate the effect of Interleukin-6 (IL-6) on pathogenesis of pregnancy induced hypertension (PIH) and to confirm the derivation of IL-6 and relationship between IL-6 and growth of placenta and fetus. METHODS: Pregnant women without infection and uterine contraction are divided into two groups: (1) PIH group (n = 57), (2) Normal pregnancy group (n = 15), reverse transcription-polymerase chain rection (RT-PCR) is used to detect IL-6 mRNA expression in leucocyto of peripheral blood and in placenta; Enzyme-linked immunosorbent assay (ELISA) is used to detect IL-6 level of peripheral blood and amniotic fluid. RESULTS: (1) The level of IL-6 and its mRNA in peripheral blood has a increasing trend as PIH degree. In moderate and severe PIH, IL-6 and its mRNA level are significantly higher than that of normal pregnancy. In each degree of PIH, IL-6 mRNA expression in placeata is significantly lower than that of normal pregnancy. In moderate and severe PIH, IL-6 level in amniotic fluid is significantly lower than that in normal pregnancy (P < 0.001). (2) In moderate and severe PIH, IL-6 level has high correlation to the IL-6 mRNA in peripheral blood (r = 0.67, P < 0.01). The IL-6 level in amniotic fluid has significant correlation to IL-6 mRNA in placenta (r = 0.79, P < 0.01). IL-6 and its mRNA in peripheral blood has no high correlation to IL-6 in amniotic fluid. (3) In severe PIH, the IL-6 mRNA in placenta and IL-6 level in amniotic fluid in the group of pregnancy with intrauterine growth retardation (IUGR) are both lower than that of the group without IUGR (P < 0.05). CONCLUSION: In PIH, the immune activity is rising, the IL-6 is overproduced by activated immune cells and it may involve in immune respond of organism and damage of vasicular endothelium. Decrease of IL-6 mRNA in placenta and IL-6 in amniotic fluid showes that the capability of production and transport of IL-6 decline in placenta of PIH patient, and these result in ischemia of placenta trophoblast and disturbance of the growth and development of placenta and fetus.

Amniotic Fluid↗
PubMed1998

[PCR in detecting the correlation between infection of HBV and cholelithiasis].

OBJECTIVE: To study the correlation between cholelithiasis and the infection of HBV. METHOD: 32 formalin-fixed and paraffin-embedded gallbladder samples of cholelithiasis patients and 20 gallbladder samples of non-cholelithiasis patients were investigated using the polymerase chain reaction-Ethidium bromide (PCR-EB) assay. The 52 patients were positive to HBV serologic markers. RESULT: The results showed that HBV-DNA was found in 13 gallbladder samples of 32 cholelithiasis patients (40.63%), significantly higher than that in 3 gallbladder samples of 20 non-cholelithiasis patients (15%). CONCLUSION: The infection of HBV and the formation of cholelithiasis are correlated.

Adult↗
PubMed1998

[Radionuclide pulmonary perfusion imaging in evaluating pulmonary hypertension in patients with congenital heart disease].

OBJECTIVE: To evaluate the degree of pulmonary hypertension in patients with congenital heart disease (CHD) by using radionuclide pulmonary perfusion imaging. METHOD: The pulmonary perfusion in 81 patients with left to right cardiac shunts was examined by scintigram with macroaggregates of (99m)Tc-labeled human serum albumin (PPS). PPS was analyzed for (1) lung regional radionuclide count (LRC), (2) right upper and lower lung count ratio (RULR), (3) kidney count ratio (KCR). The results were compared with those of cardiac catheterization exam. RESULT: There were correlation between mean pulmonary arterial pressure (mPAP), total pulmonary resistance (TPR), and PPS (KCR, RULR with mPAP gamma = 0.25, 0.35; LRC, KCR with TPR gamma = -0.34, 0.29). Five patients repeated PPS test after early operation. There were no changes in PPS. CONCLUSION: The degree of reversibility of pulmonary hypertension in patients with CHD could be quantitatively analysed by PPS.

Adolescent↗
PubMed1998

[Diagnostic value of serum creatine kinase MB in patients with cardiac damage after electric injuries].

OBJECTIVE: To investigate the incidence of cardiac damage and the diagnostic value of serum myocardial enzyme following electric injuries. METHOD: 32 patients with electrical contact injuries were evaluated by serial electrocardiograms (ECG), creatine kinase (CK) and creatine kinase MB isoenzyme (CK-MB) determinations. The patients were divided into two groups according to the ECG. RESULT: 17 patients showed abnormal ECG (Group A), and 15 normal ECG (Group B). Positive correlations were noted between CK, CK-MB and the size of electric burns. The difference of serum CK-MB and 1.1% of total CK (CK-MB in skeletal muscle) was defined as CK-MB difference. CK, CK-MB, CK-MB/total CK ratio and the CK-MB difference were significantly higher in group A than in group B (all P < 0.05). The CK-MB difference of 88% (15/17) patients in group A was more than 25 U/L, whereas that was 6.7% (1/15) in group B (P < 0.01). Six patients with CK-MB difference greater than 100 U/L had obvious cardiac damage. CONCLUSION: Cardiac damage is a common complication of electric injuries. The cardiac damage could be estimated by serum CK-MB, particularly by the CK-MB difference. The CK-MB difference might be a useful indicator for evaluating the severity of the cardiac damage.

Adolescent↗
PubMed1998

[Structure and function of saw1--a gene related to differentiation of Streptomyces ansochromogenes].

The DNA sequence of double strands of saw1 gene was determined by the method of chaintermination inhibitors. The result indicated that the 1500 bp of DNA fragment displayed a complete open reading frame (ORF), the encoding regions were located in 419 to 1252 bp positions, saw1 product has 89% identity to amino acids of sigma whiG of Streptomyces coelicolor. When recombinant plasmid containing a 1500 bp saw1 DNA fragment insert in plasmid pIJ702 was introduced into Streptomyces coelicolor C71, the sporulation deficient mutant C71 could form spore and produce grey pigment. The gene function was studied by using the method of gene disruption and the result showed that the saw1 played an important role in developmental changes from aerial hypha to spore formation of Streptomyces ansochromogenes.

Amino Acid Sequence↗