Biomedical subjects

L Jiang

Publications and source records attributed to L Jiang.

At least 73 records · Page 4Linked to original sources

PubMed2001

Role of JNK in hypertonic activation of Cl(-)-dependent Na(+)/H(+) exchange in Xenopus oocytes.

In the course of studying the hypertonicity-activated ion transporters in Xenopus oocytes, we found that activation of endogenous oocyte Na(+)/H(+) exchange activity (xoNHE) by hypertonic shrinkage required Cl(-), with an EC(50) for bath [Cl(-)] of approximately 3mM. This requirement for chloride was not supported by several nonhalide anions and was not shared by xoNHE activated by acid loading. Hypertonicity-activated xoNHE exhibited an unusual rank order of inhibitory potency among amiloride derivatives and was blocked by Cl(-) transport inhibitors. Chelation of intracellular Ca(2+) by injection of EGTA blocked hypertonic activation of xoNHE, although many inhibitors of Ca(2+)-related signaling pathways were without inhibitory effect. Hypertonicity activated oocyte extracellular signal-regulated kinase 1/2 (ERK1/2), but inhibitors of neither ERK1/2 nor p38 prevented hypertonic activation of xoNHE. However, hypertonicity also stimulated a Cl(-)-dependent increase in c-Jun NH(2)-terminal kinase (JNK) activity. Inhibition of JNK activity prevented hypertonic activation of xoNHE but not activation by acid loading. We conclude that hypertonic activation of Na(+)/H(+) exchange in Xenopus oocytes requires Cl(-) and is mediated by activation of JNK.

Amiloride↗

PubMed2001

Developmental reprogramming of rat GLUT-5 requires de novo mRNA and protein synthesis.

Fructose transporter (GLUT-5) expression is low in mid-weaning rat small intestine, increases normally after weaning is completed, and can be precociously induced by premature consumption of a high-fructose (HF) diet. In this study, an in vivo perfusion model was used to determine the mechanisms regulating this substrate-induced reprogramming of GLUT-5 development. HF (100 mM) but not high-glucose (HG) perfusion increased GLUT-5 activity and mRNA abundance. In contrast, HF and HG perfusion had no effect on Na(+)-dependent glucose transporter (SGLT-1) expression but increased c-fos and c-jun expression. Intraperitoneal injection of actinomycin D before intestinal perfusion blocked the HF-induced increase in fructose uptake rate and GLUT-5 mRNA abundance. Actinomycin D also prevented the perfusion-induced increase in c-fos and c-jun mRNA abundance but did not affect glucose uptake rate and SGLT-1 mRNA abundance. Cycloheximide blocked the HF-induced increase in fructose uptake rate but not the increase in GLUT-5 mRNA abundance and had no effect on glucose uptake rate and SGLT-1 mRNA abundance. In neonatal rats, the substrate-induced reprogramming of intestinal fructose transport is likely to involve transcription and translation of the GLUT-5 gene.

Animals↗

PubMed2001

Lactase synthesis is pretranslationally regulated in protein-deficient pigs fed a protein-sufficient diet.

The in vivo effects of protein malnutrition and protein rehabilitation on lactase phlorizin hydrolase (LPH) synthesis were examined. Five-day-old pigs were fed isocaloric diets containing 10% (deficient, n = 12) or 24% (sufficient, n = 12) protein. After 4 wk, one-half of the animals in each dietary group were infused intravenously with [(13)C(1)]leucine for 6 h, and the jejunum was analyzed for enzyme activity, mRNA abundance, and LPH polypeptide isotopic enrichment. The remaining animals were fed the protein-sufficient diet for 1 wk, and the jejunum was analyzed. Jejunal mass and lactase enzyme activity per jejunum were significantly lower in protein-deficient vs. control animals but returned to normal with rehabilitation. Protein malnutrition did not affect LPH mRNA abundance relative to elongation factor-1alpha, but rehabilitation resulted in a significant increase in LPH mRNA relative abundance. Protein malnutrition significantly lowered the LPH fractional synthesis rate (FSR; %/day), whereas the FSR of LPH in rehabilitated and control animals was similar. These results suggest that protein malnutrition decreases LPH synthesis by altering posttranslational events, whereas the jejunum responds to rehabilitation by increasing LPH mRNA relative abundance, suggesting pretranslational regulation.

Amino Acids↗

PubMed2001

GLUT-5 expression in neonatal rats: crypt-villus location and age-dependent regulation.

The rat fructose transporter normally appears after completion of weaning but can be precociously induced by early feeding of a high-fructose diet. In this study, the crypt-villus site, the metabolic nature of the signal, and the age dependence of induction were determined. In weaning rats fed high-glucose pellets, GLUT-5 mRNA expression was modest, localized mainly in the upper three-fourths of the villus, and there was little expression in the villus base. When fed high-fructose pellets, GLUT-5 mRNA expression was two to three times greater in all regions except the villus base. Intestinal perfusion in vivo of a nonmetabolizable fructose analog, 3-O-methylfructose, tended to increase fructose uptake rate and moderately increased GLUT-5 mRNA abundance but had no effect on glucose uptake rates and SGLT1 mRNA abundance. Gavage feeding of high-fructose, but not high-glucose, solutions enhanced fructose uptake only in pups > or =14 days, suggesting that GLUT-5 regulation is markedly age dependent. Fructose or its metabolites upregulate GLUT-5 expression in all enterocytes, except those in the crypt and villus base and in pups <14 days old.

Aging↗

PubMed2001

AE anion exchangers in atrial tumor cells.

Intracellular pH homeostasis and intracellular Cl(-) concentration in cardiac myocytes are regulated by anion exchange mechanisms. In physiological extracellular Cl(-) concentrations, Cl(-)/HCO(3)(-) exchange promotes intracellular acidification and Cl(-) loading sensitive to inhibition by stilbene disulfonates. We investigated the expression of AE anion exchangers in the AT-1 mouse atrial tumor cell line. Cultured AT-1 cells exhibited a substantial basal Na(+)-independent Cl(-)/HCO(3)(-) (but not Cl(-)/OH(-)) exchange activity that was inhibited by DIDS but not by dibenzamidostilbene disulfonic acid (DBDS). AT-1 cell Cl(-)/HCO(3)(-) activity was stimulated two- to threefold by extracellular ATP and ANG II. AE mRNAs detected by RT-PCR in AT-1 cells included brain AE3 (bAE3), cardiac AE3 (cAE3), AE2a, AE2b, AE2c1, AE2c2, and erythroid AE1 (eAE1), but not kidney AE1 (kAE1). Cultured AT-1 cells expressed AE2, cAE3, and bAE3 polypeptides, which were detected by immunoblot and immunocytochemistry. An AE1-like epitope was detected by immunocytochemistry but not by immunoblot. Both bAE3 and cAE3 were present in intact AT-1 tumors. Cultured AT-1 cells provide a useful system for the study of mediators and regulators of Cl(-)/HCO(3)(-) exchange activity in an atrial cell type.

4,4'-Diisothiocyanostilbene-2,2'-Disulfonic Acid↗

PubMed2001

Intestinal perfusion induces rapid activation of immediate-early genes in weaning rats.

C-fos and c-jun are immediate-early genes (IEGs) that are rapidly expressed after a variety of stimuli. Products of these genes subsequently bind to DNA regulatory elements of target genes to modulate their transcription. In rat small intestine, IEG mRNA expression increases dramatically after refeeding following a 48-h fast. We used an in vivo intestinal perfusion model to test the hypothesis that metabolism of absorbed nutrients stimulates the expression of IEGs. Compared with those of unperfused intestines, IEG mRNA levels increased up to 11 times after intestinal perfusion for 0.3-4 h with Ringer solutions containing high (100 mM) fructose (HF), glucose (HG), or mannitol (HM). Abundance of mRNA returned to preperfusion levels after 8 h. Levels of c-fos and c-jun mRNA and proteins were modest and evenly distributed among enterocytes lining the villi of unperfused intestines. HF and HM perfusion markedly enhanced IEG mRNA expression along the entire villus axis. The perfusion-induced increase in IEG expression was inhibited by actinomycin-D. Luminal perfusion induces transient but dramatic increases in c-fos and c-jun expression in villus enterocytes. Induction does not require metabolizable or absorbable nutrients but may involve de novo gene transcription in cells along the villus.

Animals↗

PubMed2001

Effect of structural modification on photodynamic activity of hypocrellins.

Aluminum ion complexed 5,8-di-Br-hypocrellin B is a new water-soluble perylenequinonoid derivative with enhanced absorption over hypocrellin B (HB) in the phototherapeutic window (600-900 nm). Electron paramagnetic resonance and 9,10-diphenyl-anthracene bleaching methods were used to investigate the photosensitizing activity of [AL2(5,8-di-Br-HB)Cl4]n in the presence of oxygen. Singlet oxygen, superoxide anion radical and hydroxyl radical can be generated by [AL2(5,8-di-Br-HB)CL4]n photosensitization. Singlet oxygen (1O2) is formed via energy transfer from triplet-state [AL2(5,8-di-Br-HB)CL4]n to ground-state molecular oxygen. 1O2 participates in the generation of a portion of superoxide anion radical (O2.-). Besides superoxide anion radical (O2.-) may originate from the electron transfer between the triplet-state [AL2(5,8-di-Br-HB)CL4]n and the ground-state molecular oxygen. OH is formed through the Fenton-Haber-Weiss reaction and the decomposition of DMPO-1O2 adduct. Compared with HB [AL2(5,8-di-Br-HB)CL4]n primarily remains and enhances the generation efficiency of superoxide anion radical and hydroxyl radical but that of singlet oxygen decreases.

Electron Spin Resonance Spectroscopy↗

PubMed2001

[Cloning of the mouse Doc-1R gene by genomic walking].

OBJECTIVE: To obtain the genomic sequences of the mouse Doc-1R gene. METHODS: Gene-specific primers were designed and synthesized based on the cDNA sequences of the mouse Doc-1R gene. With the use of genomic walking strategy, the mouse genomic walking library was amplified by the polymerase chain reaction(PCR). Mouse genomic library constructed with a special adaptor was utilized as a template to amplify the desired fragment by nested PCR. RESULTS: A desired fragment of 1.5 kb was obtained. Sequence analysis of the desired fragment confirmed that the genomic cloning of the Doc-1R gene was successful. This gene contains four exons and three introns. All of the splice donor/acceptor site sequences are in accordance with the consensus 'GT-AG' rule. CONCLUSION: The genomic walking strategy is simple, efficient and reliable; it is an ideal method of cloning genomic fragments.

Animals↗

PubMed2001

Elevated interleukin-13 in patients with active lupus nephritis.

OBJECTIVE: To investigate the significance of interleukin-13 (IL-13) in patients with active lupus nephritis (LN). METHODS: Ten healthy volunteers and 16 patients with active LN were included in this study. The protein level of IL-13 in plasma was examined by enzyme linked immunosorbent assay (ELISA), and gene expression of IL-13 in peripheral blood mononuclear cells (PBMCs) by reverse transcription polymerase chain reaction (RT-PCR). Expression of IL-13 mRNA in renal tissue was studied by in situ hybridization (ISH) techniques. RESULTS: The level of IL-13 in plasma and the expression of IL-13 mRNA in PBMCs were significantly higher in LN patients than those in the controls (P < 0.001). Increased expression of IL-13 mRNA was detected in renal tissue of active LN patients compared to those in the controls (P < 0.001). Analysis of the linear correlation indicated that the level of IL-13 mRNA in the tubulointerstitial area in patients with active LN correlated with the concentration of serum creatinine (Scr), the glomerular activity index (GAI), the activity index of tubulointerstitium, and the level of serum C3 (P < 0.05 for each). CONCLUSION: The elevation of IL-13 may play an important role in the molecular pathogenesis of active LN.

Adult↗

PubMed2001

[Isozyme analysis of Gastrodia elata f. elata and G. elata f. glaucca and their hybrid].

Peroxidase(POX) isozyme analysis of Gastrodia elata f. glaucca, G. elata f. elata and its hybrid were carried out. The results indicated that shoot apex meristem was optimal material for POX analysis and the determination of the hybrid. The zymogram hands were stable and clear. POX isozyme zymogram of the hybrid F1(H x W) represented the visible supplement relation between Gastrodia elata f. elata and Gastrodia elata f. glaucca.

Gastrodia↗

PubMed2001

[Immunohistochemical and ultrastructural study of basement membrane in oral verrucous carcinoma].

OBJECTIVE: To study the immunohistochemical alteration of basement membrane (BM) type IV collagen and laminin in oral verrucous carcinoma and its BM ultrastructural variations. METHODS: 16 cases of oral verrucous carcinoma (OVC), 10 cases of oral squamous cell carcinoma (OSCC) and 9 cases of oral mild to severe epithelial dysplasia (OMSD) were studied by using a immunohistochemical S-P method, and the results were analyzed by quantitative method. 3 cases of OVC were observed by TEM. RESULTS: The BM in OVC was thicker than in OSCC and OMSD. TEM found the basal lamina in some areas showed a marked reduplication. The BM in OVC was generally intact (13/16), whereas in OSCC it was mostly discontinuous (9/10), especially around the neoplasm front or the small cord consisted of a few cells, and mostly continuous in OMSD (6/9). There was a stromal inflammatory infiltration around tumor nests for all the oral lesions, but it was much heavier in OVC than that in OSCC and OMSD (P < 0.05). There was a positive correlation between intraepithelial lymphocytic infiltration and the BM continuity for OVC(P < 0.01). CONCLUSIONS: The more continuous BM and the heavier inflammatory infiltration in the connective tissue of OVC may be related to its biological behavior.

Basement Membrane↗

PubMed2001

Expression of oncoproteins c-fos and c-jun in hypertrophic scars and chronic dermal ulcers and their regulation of basic fibroblast growth factor.

OBJECTIVE: To explore the characteristics of oncoprotein expression of c-fos and c-jun in hypertrophic scars and chronic dermal ulcers and their regulation of basic fibroblast growth factor (bFGF). METHODS: Tissues of hypertrophic scars (n = 8), chronic dermal ulcers (n = 8) and normal skin (n = 5) were taken from 21 patients with burns and chronic dermal ulcers in operation. The ABC immunohistochemical method was used to characterize the gene product expression of c-fos, c-jun and bFGF in the above tissues. RESULTS: In normal skin, both c-fos and c-jun protein expression and bFGF protein expression were observed. The signals of both oncoproteins were localized mainly in subcutaneous fibroblasts, but, positive expression of the bFGF protein was mainly in keratinocytes. In hypertrophic scars, positive expression of both oncoproteins could be found mainly in fibroblasts, but bFGF was mainly in fibroblasts and endothelial cells. In chronic dermal ulcers, endothelial cells, some of inflammatory cells and fibroblasts were positive for both of oncoproteins, but the expression of bFGF was only seen in fibroblasts and endothelial cells. CONCLUSIONS: The results indicate that the interaction between both oncoproteins and bFGF exists, and the regulating action between protooncogenes and bFGF is a major course in wound healing. The different expressions of c-fos and c-jun gene products play an important role in regulate bFGF action, thus affecting wound healing.

Chronic Disease↗

PubMed2001

Expression characteristics of c-fos, c-myc and bFGF in early burn tissue.

OBJECTIVE: To investigate the sequence and characteristics of expression of proto-oncogenes, c-fos, c-myc and endogenous basic fibroblast growth factor (bFGF), in burn tissue from rats. METHODS: A partial thickness burn of 30% TBSA was created on the backs of Wistar rats. Immunohistochemistry was used to detect the expression of these proteins in normal and burned skin at 3 hours, 6 hours, 1 day, 3 days, 7 days and 14 days postburn. RESULTS: Expression of c-fos, c-myc and bFGF was induced by the burn, but these three proteins showed different expression levels in sequence and distribution. Expression of c-fos increased and peaked at 3 hours postburn. Stain positive granules were distributed mainly in the cytoplasm of basal cells and the nuclei of fibroblasts. The expression of bFGF protein increased at 6 hours and peaked at 1 day postburn; it was distributed in the cytoplasm of fibroblasts. c-myc protein peaked at 3 days postburn and was also distributed in the cytoplasm of fibroblasts. CONCLUSIONS: Thermal injury can induce c-fos, c-myc and bFGF expression and show phasic control and regional distribution. The phasic expression of these three proteins indicates that there maybe a regulatory relationship between proto-oncogenes and growth factors in early burn. This may play an important role in late tissue repair.

Animals↗

PubMed2001

Relationship between c-fos gene expression and delayed neuronal death in rat neonatal hippocampus following hypoxic-ischemic insult.

OBJECTIVE: To explore the mechanism of perinatal hypoxia-ischemia encephalopathy, we studied the expression of the c-fos gene and its relationship with delayed neuronal death in a rat model. METHODS: Cerebral hypoxia-ischemia was produced in 7-day-old SD rats using the Rice model. Reverse transcription PCR (RT-PCR), immunohistochemistry and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) were used to detect the expression of c-fos gene and cell apoptosis in the hippocampus. RESULTS: The selective expression of c-fos and delayed cell apoptosis were observed in the hypoxia-ischemia hippocampus. Expression of the c-fos gene was seen in the CA4 and cingulate sulcus neurons, and apoptosis was observed in the CA1 neurons. CONCLUSION: Transient expression of the c-fos gene may induce cerebral cell apoptosis, and may have complex relations with delayed cell death.

Animals↗

PubMed2001

[The adhesion and seeding of NIH3T3 fibroblast on PHB surfaces].

Biodegradable polymers have been widely used in the field of tissue engineering. The adhesive characteristic of polymer surfaces is critical for cell seeding and growth. The adhesion and growth of NIH3T3 fibroblast on poly-beta-hydroxybutrpic acid (PHB) was studied here, and the cell-surface adhesion strength was measured in a shear flow detachment assay. It showed that the critical shear stress for cell detachment was relatively low on PHB, thus cells tend to aggregate and detach from surfaces. On the other hand, cells tend to spread and formed monolayer on poly-lysine coated PHB surface. When the PHB foams scaffolds were coated by poly-lysine, the seeding percentage of cells was also greatly enhanced.

3T3 Cells↗

PubMed2001

Establishment of an animal model of chronic atrophic gastritis and a study on the factors inducing atrophy.

OBJECTIVE: To establish a rat model of chronic atrophic gastritis and explore the factors inducing atrophy. METHODS: In accordance with repeated orthogonal design of L8(2(7)), 60% alcohol and 20 mmol/L sodium deoxycholate (served as factor A), 0.05%-0.1% ammonia water (factor B), 0.05% indomethacin (factor C) were given, alone or in combination, to rats in three experiments for 3 months, 6 months or 9 months respectively. Then the rats were dissected, and their pathologic changes of the gastric mucosa were assessed. RESULTS: Typical signs of chronic atrophic gastritis (CAG) were found in all rats which were treated with factor A, B, C alone or in combination for 6 or 9 months. No significant difference of pathologic changes of gastric mucosa was found between the rats treated for 6 months and those for 9 months. No obvious CAG signs were found in the rats treated with factor A, B, C for 3 months. CONCLUSION: Sixty percent of alcohol, 20 mmol/L sodium deoxycholate, 0.05%-0.1% ammonia water and 0.05% indomethacin given to Sprague-Dawley rats for 6 months can successfully establish the animal model of CAG. Prolongation of the model-establishment time is not able to further facilitate the atrophy of gastric mucosa.

Ammonia↗

PubMed2001

[Study on the application of quantitative analysis of cell-wall amino acids in actinomycetes classification].

This paper has collected 70 recognized type strains of actinomycete from home and abroad Microbiological culture collection centers. Adopting thin-layer chromatography and thin-layer chromatogram scanner methods to quantitatively analyze the composition of cell-wall amino acids in actinomycete. It has made comparison between quantitative results and qualitative ones. After a thorough discussion, a revision is made on the standard of dividing cell-wall types in actinomycete chemical classification, which has provided some original suggestion in hope of improving the research of actinomycete chemical classification.

Actinobacteria↗

PubMed2001

[Preliminary study on citral impaires the Aspergillus flavus membrane].

Compared with the normally growing A. flauas, the content as below was determined: the utilization ratio to protein and reducing sugar of hyphostroma poisened by citral, the activity of [Na+, K+]-ATPase capable of decomposition ATP, and the seepagevity ratio of electrolyte. In addition, the shape change in spore was observed via the scanning electron microscope (SEM) and the fast multi-channel micro-spectrophotomer (FMCM). The result above all suggested facts as following after it's poised by the citral in MIC. The surface of hyphostroma and spore turned into be porous and rough. The pass trace on spore shriveled and closed. The rate of conduct electricity increased by 52.8%. The utilization ratio to protein and reducing sugar respectively decreased 61.5% and 44.3%. The rate of spore's sprout dropped to 61.4%. The molecular structure of membrane was so distinctly changed that it lost the selective permeability. There was inhibition on hyphostroma growth and spore sprout.

Absorption↗