Biomedical subjects

Y Ding

Publications and source records attributed to Y Ding.

At least 199 records · Page 11Linked to original sources

PubMed1998

Depressed renal and vascular nitric oxide synthase expression in cyclosporine-induced hypertension.

BACKGROUND: Introduction of cyclosporine (CsA) for clinical use has greatly enhanced the outcome of organ transplantation. However, CsA can cause nephrotoxicity and hypertension (HTN). This study was designed to test the hypothesis that CsA-induced HTN is related to depressed nitric oxide (NO) production. METHODS: Urinary excretion of NO metabolites (NOx) and endothelial and inducible NO synthase (eNOS and iNOS) proteins were determined in thoracic aortas and kidneys of CsA-treated (given CsA 18 mg/kg/day for 3 weeks) and placebo-treated rats. In addition, renal tissue eNOS and iNOS mRNA and aorta iNOS activity were measured. RESULTS: CsA administration resulted ina significant rise in arterial blood pressure (BP) coupled with a steady decline in urinary NOx excretion, suggesting depressed NO production. This was accompanied by a significant reduction in iNOS protein abundance in the kidney and thoracic aorta but no change in eNOS protein abundance. The fall in renal iNOS protein in CsA-treated rats was accompanied by a parallel decline in iNOS mRNA abundance and enzymatic activity. CONCLUSION: Administration of CsA for three weeks resulted in a significant rise in BP together with marked reductions in urinary NOx excretion, and renal and vascular iNOS expression. These observations suggest that CsA-induced HTN may be, in part, related to impaired NO production. If true, strategies designed to restore NO availability may mitigate HTN and other vascular complications of CsA therapy.

Animals↗

PubMed1998

Role of increased oxygen free radical activity in the pathogenesis of uremic hypertension.

Earlier studies have demonstrated increased oxygen free radical (OFR) activity, diminished antioxidant capacity and reduced OFR-inactivating enzymes in chronic renal failure (CRF). Via inactivation of nitric oxide (NO), oxidation of arachidonic acid and a direct vasoconstrictive action, OFR can potentially raise blood pressure (BP). This study was designed to test the hypothesis that increased OFR activity may contribute to CRF hypertension. Four weeks after 5/6 nephrectomy rats were treated for two weeks with either lazaroid, a potent antioxidant and lipid peroxidation inhibitor (CRF-LZ group), or vehicle alone (CRF group) by daily gastric gavage. The control group was sham operated and placebo treated. The CRF group exhibited significant increases in BP and plasma lipid peroxidation product, malondialdehyde (MDA), indicating enhanced OFR activity. This was accompanied by decreased urinary nitrate/nitrite (NOx) excretion suggesting depressed NO production. LZ therapy normalized plasma MDA and significantly ameliorated CRF-induced hypertension. Both MDA and blood pressure (BP) rose to values seen in the untreated CRF group within two weeks after termination of LZ therapy. Intravenous administration of the hydroxyl radical scavenger, dimethylthiourea (DMTU), significantly lowered BP and raised urinary NOx excretion. However, no discernible effects were found with either superoxide dismutase or catalase (superoxide and H2O2 quenchers). The results suggest that increased OFR activity is, in part, responsible for CRF-associated HTN. The study further points to hydroxyl radicals as the major source of OFR in CRF animals. If substantiated in humans, antioxidant therapy becomes a logical adjunct in the management of CRF.

Animals↗

PubMed1998

Linkage of the gene for an autosomal dominant form of juvenile amyotrophic lateral sclerosis to chromosome 9q34.

We performed genetic mapping studies of an 11-generation pedigree with an autosomal dominant, juvenile-onset motor-systems disease. The disorder is characterized by slow progression, distal limb amyotrophy, and pyramidal tract signs associated with severe loss of motor neurons in the brain stem and spinal cord. The gene for this disorder, classified as a form of juvenile amyotrophic lateral sclerosis (ALS), is designated "ALS4." We performed a genomewide search and detected strong evidence for linkage of the ALS4 locus to markers from chromosome 9q34. The highest LOD score (Z) was obtained with D9S1847 (Z=18.8, recombination fraction of .00). An analysis of recombinant events identified D9S1831 and D9S164 as flanking markers, on chromosome 9q34, that define an approximately 5-cM interval that harbors the ALS4 gene. These results extend the degree of heterogeneity within familial ALS syndromes, and they implicate a gene on chromosome 9q34 as critical for motor-neuron function.

Adolescent↗

PubMed1998

Escherichia coli prlC gene encodes a trypsin-like proteinase regulating the cell cycle.

Proteinase In has previously been described as displaying a trypsin-like proteinase activity that momentarily appears immediately before DNA synthesis in the cell cycle of Escherichia coli synchronized by phosphate starvation and which is closely related to the initiation of DNA replication [Kato, M., Irisawa, T., Ohtani, M., and Muramatu, M. (1992) Eur. J. Biochem. 210, 1007-1014]. We purified the proteinase In from E. coli C600 and found that the 15 amino acid residues of its amino-terminal were identical with those of oligopeptidase A (OpdA), the product of the E. coli prlC gene. The purified proteinase had a molecular mass of approximately 67 kDa, which was also the same as that of oligopeptidase A. To further elucidate the relationship between proteinase In and oligopeptidase A, we assembled an expression vector to direct the synthesis of E. coli oligopeptidase A. The protein was expressed at a high level in E. coli BL21(DE3) and was produced mostly in the soluble, active form. Both the recombinant enzyme (rPrlC) and the purified proteinase In could hydrolyze trypsin substrates for proteinase In as well as benzyloxycarbonyl Ala- Ala-Leu p-nitroanilide (Z-AALpNA), described as a synthetic substrate for oligopeptidase A. The effects of various protease inhibitors on rPrlC were also very similar to those on proteinase In. The trypsin inhibitors 4-guanidino benzoic acid 4-tert-butylphenyl ester and antipain strongly inhibited the trypsin-like proteinase activity of the recombinant enzyme, but had no effect on its Z-AALpNA hydrolyzing activity. Cobalt ion, which greatly enhanced the OpdA activity, slightly inhibited the trypsin-like activity of the recombinant enzyme. These results strongly suggest that proteinase In is encoded by the E. coli prlC gene and is a multi-functional proteinase with two separate active sites.

Base Sequence↗

PubMed1998

Calcium channel blockade enhances nitric oxide synthase expression by cultured endothelial cells.

In a recent study, we found marked increases in nitric oxide (NO) production and endothelial and inducible NO synthase (eNOS and iNOS) expressions with calcium channel blockade in rats with chronic renal failure. This study was undertaken to determine whether enhanced NO production with calcium channel blockade is a direct effect of this therapy or a consequence of the associated hemodynamic and humoral changes. We tested the effects of a calcium channel blocker, felodipine (10(-5), 10(-6), and 10(-7) mol/L), on nitrate and nitrite (NOx) generation, Ca2+-dependent and -independent NOS activity, and eNOS and iNOS protein masses in proliferating and quiescent rat aortic endothelial cells in culture. Compared with vehicle alone, felodipine significantly increased NOx generation, Ca2+-dependent NOS activity, and eNOS protein mass in proliferating and quiescent endothelial cells. Felodipine did not modify the stimulatory action of 10% fetal calf serum on DNA synthesis (thymidine incorporation) and cell proliferation. Ca2+-independent NOS activity and iNOS protein expression were negligible and unaffected by calcium channel blockade. NOx production and NOS expression were greater in proliferating cells than in quiescent cells. Thus, calcium channel blockade upregulates endothelial NO production in vitro, confirming our previous in vivo study. This observation indicates that the reductions in cytosolic [Ca2+] and vasodilation with calcium channel blockade are not only due to inhibition of Ca2+ entry but also to an NO-cGMP mediated mechanism.

Animals↗

PubMed1998

Evidence for the existence of CCK-producing cells in rat pancreatic islets.

BACKGROUND: Although the existence of cholecystokinin-like immunoreactivity (CCK-LI) in rat pancreas had been reported previously, it was never clearly demonstrated whether CCK is produced in rat pancreatic islets. AIMS: The purpose of this study was to elucidate the source of the CCK-LI, the molecular properties of CCK, and the expression of the CCK gene in islet cells. METHODS: Immunohistochemical studies of rat pancreas were carried out with different rabbit antisera against CCK-8 and CCK-related peptide including N-terminal CCK-33 (1-22) and gastrin-17, and colocalization with known islet hormones including insulin, glucagon, somatostatin, and pancreatic polypeptide was investigated. The major molecular form of CCK in the islets was determined by HPLC. RT-PCR and in situ hybridization were performed to demonstrate the presence of the CCK transcript in the pancreas. RESULTS: CCK-LI was found in the center of the islets, colocalized with insulin in B cells. The major molecular form of CCK in the islets was CCK-8. A 350-nucleotide fragment of PCR-amplified CCK cDNA was detected in the islet as well as the duodenum by RT-PCR. In situ hybridization showed that CCK messenger RNA was located in a large portion of the islets, and this was consistent with the immunohistochemical findings. CONCLUSION: CCK messenger RNA and immunoreactivity are expressed in adult rat pancreatic islets, indicating that CCK-producing cells are present in adult rat islets.

Animals↗

PubMed1998

A single stranded DNA-binding protein, ssCRE-BP/Pur alpha, in rat lung and its increase in allergic airway inflammation.

ssCRE-BP/Pur alpha is a single stranded DNA-binding protein and may be involved in gene replication and transcription and in the development of morphine dependence. We found a ssCRE-BP/Pur alpha (45 kDa) in rat lung that was larger than those (40 kDa) identified in rat and mouse brains and mouse lung. Immunohistochemistry showed that ssCRE-BP/Pur alpha is primarily distributed in the lung epithelium. As allergic inflammation induces various gene expressions, we investigated the changes of Pur alpha during airway inflammation. Ovalbumin-sensitized rats were used for inducing allergic airway inflammation. The expression and DNA-binding activity of 45-kDa ssCRE-BP/Pur alpha were significantly increased in the sensitized rat lungs 24 hr after antigen challenge, but not in those of rats nonsensitized or sensitized with ovalbumin and challenged with saline. Immunohistochemistry and in situ hybridization demonstrated that the vascular endothelial cells and numerous infiltrated eosinophils around the airways were stained with anti-Pur alpha antibody. These data suggest that rat lung and the eosinophils contain a 45-kDa ssCRE-BP/Pur alpha that is increased when airway inflammation occurs.

Animals↗

PubMed1998

[Discovery of ten strains of non-O1 Vibrio cholerae pigmentogens].

OBJECTIVE: To study the distribution of non-O1 Vibrio cholerae pigmentogens in water and its biological characteristics and pathogenicity. METHODS: Samples were collected from local source of drinking water and cultured for pathogenic V. cholerae. Non-O1 V. cholerae was isolated and identified with nutrient agar slant instead of KIA. RESULTS: Ten strains of V. cholerae producing pigment with negative Gram's stain were detected in the source water in Lu' an Prefecture, Anhui Province during 1994 to 1997, which could all met the definition of non-O1 V. cholerae in morphology, cultural characteristics, biochemistry and serology, with systematic identification. Animal experiments showed that it had strong virulence. CONCLUSION: These strains of V. cholerae cultured in basic cholate agar, nutrient agar slant and blood agar could produce brown pigment, so it was called non-O1 V. cholerae pigmentogens.

Animals↗

PubMed1998

Detection of Fas/APO-1 in six human urogenital malignant cell lines with flow cytometry.

OBJECTIVE: To investigate the expression of Fas/APO-1 in urogenital tumor cell lines. METHODS: With direct immunofluorescence, the expression of Fas/APO-1 in six urogenital malignant cell lines and one primary in vitro cultured normal renal fibroblast was detected by flow cytometry. RESULTS: Expression of Fas/APO-1 was detected in all six urogenital tumor cell lines, but with limited positive cell percentage and relatively lower fluorescence intensity, compared with expression of Fas/APO-1 in normal control of primary in vitro cultured renal fibroblast. CONCLUSIONS: Lower expression of Fas/APO-1 in urogenital malignant cell lines than that in normal cells might be the reason for occurrence and progression of urogenital malignant tumors.

Apoptosis↗

PubMed1998

[Mechanism of CD44V6 in human colorectal carcinoma metastasis].

OBJECTIVE: To study the mechanism of CD44V6 in human colorectal carcinoma (HCC) matastasis. METHODS: The effects of CD44V6 on HCC cell adhering to base membrane and vascular endothelium were investigated by human amniotic membrane invasion model and co-culturing HCC cell with vascular endothelium. The influence of CD44V6 variants on cytoskeleton and gap junctional intercellular communication (GJIC) was studied by immunofluorescent confocal 3-dimensional reconstruction and fluorescence recovery after photobleaching technique. RESULTS: CD44V6 antibody can decrease the ability of HCC cells to adhere to amniotic membrane and vascular endothelium. It also can affect the distribution, polymerization and depolymerization of actin of HCC cells, but does not significantly affect GJIC of HCC cells. CONCLUSIONS: CD44V6 may play an important role in promoting HCC cells to adhere to vascular endothelium and base membranes and may affect the distribution, polymerization and depolymerization of actin in HCC cells and facilitate HCC cell metastasis.

Coculture Techniques↗

PubMed1998

[A comparative study of serological, monoclonal antibody and DNA typing in identifying HLA-A].

OBJECTIVE: A double-blind study was carried out to evaluate the accuracy and reliability of PCR-SSP assay in comparison with serology and monoclonal antibody(mAb) typing in identifying HLA-A alleles in Southern Chinese population. METHODS: A total of 296 samples were entered into the study, including 143 unrelated kidney donors and 153 recipients. HLA-A typing was performed by standard two-stage microlymphocytotoxicity assay, one-step mAb typing and PCR-SSP typing. RESULTS: All samples were successfully typed by PCR-SSP. Reproducibility was 100%. The results were confirmed by a panel of standard DNAs and a double-blind typing of UCLA tissue typing lab. However, mAb typing(for Asian) in 149 samples showed 2.7% misassignment including 1 antigen being incorrectly interperted and 3 of 26 "blanks" turning out to be definable alleles by DNA typing. Serological discrepancy rate was 15.6% in 147 samples consisting of 8 antigens being incorrectly interpreted, 13 "blanks" turning out to be definable alleles and 2 heterozygotes turning out to be homozygotes by DNA typing. CONCLUSION: HLA-A typing by PCR-SSP proved to be a rapid and accurate technique, suitable for clinical application with a greater precision than serology. In large scale screening, mAb typing (for Asian) is recommended. Antigens of "blanks" or "difficult" by serology or mAb typing should be retyped by DNA typing.

Alleles↗

PubMed1998

[Expression of CD44V6 and its effects on cytoskeleton in human colorectal carcinoma cell lines].

OBJECTIVE: To observe the expression of CD44V6 and its effects on cytoskeleton in human colorectal carcinoma(HCC) HT29 and LoVo cell lines. METHODS: Expression of CD44V6 variant in HCC HT29 and LoVo cell lines was investigated by in situ hybridization, immunohistochemistry and quantitative immunofluorescence technique. The effects of CD44V6 variants on cytoskeleton was studied by immunofluorescence and confocal 3 dimension reconstruction technique. RESULTS: CD44V6 was expressed at the mRNA and protein levels in both HT29 and LoVo cell lines, but the expression was higher in LoVo cells than in HT29 cells. When the HT29 cells and LoVo cells were blocked by monoclonal antibodies, it was found that changes developed in the cytoskeleton of these cells. CONCLUSIONS: The expression of CD44V6 is related to the metastatic potentiality of human colorectal carcinoma cells. CD44V6 may affect the distribution, polymerization and depolymerization of actin of HCC cells and promote HCC cell metastasis.

Actins↗

PubMed1998

[The relation between DNA replication error and clinicopathological features of colorectal carcinoma].

OBJECTIVE: To study the relationship between DNA replication error and development of colorectal carcinoma (CRC). METHODS: Silver staining PCR-SSCP and denatured polyacrylamide gel electrophoresis methods were used to detect microsatellites instability (MSI) at 4 loci on chromosome 2, 5, 17 in paraffin embedded specimens of 60 CRC and their paired normal tissue. If replication errors (RER) were found at 2 or more loci, then a diagnosis of RER+ was made. RESULTS: RER+ was observed in 19/60 CRC, among which 7 cases had CRC family history. According to Amsterdam criteria, 4 were diagnosed as HNPCC(hereditary nonpolyposis colorectal cancer), of which 3 cases were RER+. The ratio of RER+ in HNPCC (75%) was significantly higher than that among sporadic CRC (28.5%). Most RER+ CRC have features of poorly differentiated adenocarcinoma (P < 0.01), tendency for right side involvement of the colon (P < 0.05) and a higher proportion with family history (P < 0.05). Rate of Dukes A and B stage higher than C and D stage (P < 0.05). CONCLUSION: RER+ is a relatively common molecular event in CRC. RER+ CRC and RER- CRC have different clinicopathological features and behavior.

Adenocarcinoma↗

PubMed1998

[Application of capillary electrophoresis on environmental analysis].

A review of applications of capillary electrophoresis (CE) on environmental analysis is presented, based mainly on the worldwide published works in the latest years. The current achievements and application potential of CE in the field of environmental analysis are included with 58 references.

Electrophoresis, Capillary↗

PubMed1998

[On the best time for harvesting Dendrobium candidum Wall. ex Lindl].

OBJECTIVE: To explore the theory on the best time for harvesting Dendrobium candidum so that the production of the herb can be directed more effectively. METHOD: Based on a component analysis in combination with mathematical calculation, a synthetical appraisal on the yield, contents of effective components and efficacy of D. candidum in different growing periods has been made, and different appraisal indexes and synthetical harvesting indexes have been worked out. RESULT: The harvesting indexes from the first year to the fourth year are as follows: 5.69, 9.54, 17.9, 22.2 (curing throat and eye diseases); 11.2, 14.6, 21.6, 17.6(strengthening immunity); 8.44, 12.1, 19.7, 19.9(the above-mentioned indexes and yield factor considered together). CONCLUSION: The best time for harvesting D. candidum is in the fourth year for curing throat and eye diseases; in the third or first year for strengthening immunity; and in autumn of the third year if the above-mentioned indexes and yield factor are to be considered together.

Alkaloids↗

PubMed1998

[Effect of yuanhua on isolated uterine strips in unpregnant rats].

OBJECTIVE: To explore the mechanism on the effect of Yuanhua on the contractile activity of isolated uterine strips in rats under artificial oestrum. METHOD: Isolated strips were suspended in a tissue chamber in which Yuanhua was added with some antagonists of inhibitors or without. RESULT: Yuanhua could excite the uterine smooth muscle strips in a dose-dependent manner, but atropine, phentolamine, hexamethonium and diphenhydramine could not inhibit this exciting action. This exciting effect could be inhibited completely by verapamil and decreased by indomethacin(inhibitor of prostaglandin synthase). CONCLUSION: The exciting effect of Yuanhua on un-pregnant rats in vitro might be related to an action on the cell membrane Ca2+ channel as well as to a partial stimulation of synthesis and release of PG.

Animals↗

PubMed1998

[The effect of local growth in long bones following two different epiphyseal-stimulating procedures: an experimental study].

OBJECTIVE: To study the effect of local growth in long bones of the rabbits following two different epiphyseal-stimulating procedures. METHODS: These were osteotomy in the metaphysis near the proximal tibial epiphyseal plate and hemicirecumferential periosteal excision on the proximal tibial epiphysis. Tibia roentgenography, tetracycline labelling, histological method and electron microscopy were used. RESULTS: The local stimulating effect following hemi-circumferential periosteal excision was more evident than following osteotomy. CONCLUSION: The procedure of periosteal excision could be good for the treatment of children knee' deformity.

Animals↗

PubMed1998

[Apoptosis induced by ionizing radiation in TCC cell lines, EJ and BIU-87].

OBJECTIVE: To study the effect of ionizing radiation on the living status of TCC cell lines, EJ and BIU-87. METHODS: Different doses of X-ray were used on cell lines, EJ and BIU-87, and the cells were observed microscopically by fluorescent staining(EB and AO). RESULTS: The number of normal living cells declined and apoptotic as well as necrotic cells elevated with increase of radiation doses except for doses equal to or below 100 cGY, Apoptotic and necrotic cells increased as postradiation time delayed. CONCLUSION: The ionizing radiation may induce TCC apoptosis and necrosis.

Apoptosis↗