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Biomedical subjects

Y Jiang

Publications and source records attributed to Y Jiang.

At least 145 records · Page 8Linked to original sources
PubMed2001

Effects of calcium on antioxidant activities and water relations associated with heat tolerance in two cool-season grasses.

Calcium (Ca2+) may be involved in plant tolerance to heat stress by regulating antioxidant metabolism or/and water relations. This study was designed to examine whether external Ca2+ treatment would improve heat tolerance in two C(3), cool-season grass species, tall fescue (Festuca arundinacea L.) and Kentucky bluegrass (Poa pratensis L.), and to determine the physiological mechanisms of Ca2+ effects on grass tolerance to heat stress. Grasses were treated with CaCl(2) (10 mM) or H(2)O by foliar application and then exposed to heat stress (35/30 degrees C) in growth chambers. Some of the Ca2+ -untreated plants were maintained at 20/15 degrees C as the temperature control. Heat stress reduced grass quality, relative water content (RWC), and chlorophyll (Chl) content of leaves in both species, but Ca2+ treatment increased all three factors under heat stress. The Ca2+ concentration in cell saps increased with heat stress and with external Ca2+ treatment in both species. Osmotic potential increased with heat stress, but external Ca2+ treatment had no effect. Osmotic adjustment increased during short-term heat stress, but then decreased with a prolonged period of stress; it was not influenced by Ca2+ treatment. The activity of superoxide dismutase (SOD) in both species increased transiently at 12 d of heat stress and then remained at a level similar to that of the control. External Ca2+ treatment had no effect on SOD activity. The activities of catalase (CAT), ascorbate peroxidase (AP), and glutathione reductase (GR) of both species decreased during heat stress. Plants treated with Ca2+ under heat stress had higher CAT, GR and AP activities than untreated plants. Lesser amounts of malondialdehyde (MDA) accumulated in Ca2+ -treated plants than in untreated plants during extended periods of heat stress. The results suggested that exogenous Ca2+ treatment enhanced heat tolerance in both tall fescue and Kentucky bluegrass. This enhancement was related to the maintenance of antioxidant activities and a decrease in membrane lipid peroxidation, but not to the regulation of osmotic potential and osmotic adjustment.

Antioxidants↗
PubMed2001

[Establishment of platelet-mediated transmitochondrial cell model].

OBJECTIVE: To establish a transmitochondrial cell model for further researches on molecular genetics of mitochondrial related disease. METHODS: The fusion process was conducted between mitochondrial DNA-lacking rho degrees cell (a gift from NIH) and platelet using polyethylene glycol as fusion promoting reagent. The fusion cells were confirmed by PCR and electronic microscopic cytochemistry. The mitochondrial morphology and function of 3 families of Rett syndrome were investigated. RESULTS: The platelet-mediated transmitochondrial cell model was constructed successfully. The frequency of transformation ranged from 0.5 to 1.6 clones in 10(4) recipient cells. The mitochondrial vacuolation was occasionally observed in 2 cases of Rett syndrome. CONCLUSION: Transmitochondrial cell model can be applied to assessment of the mitochondrial morphology and function of fusion cells and is found to be of great use in evaluating the gene expression of mitochondrial genome at different levels.

Blood Platelets↗
PubMed2001

[Fas and ICE expression in the hepatocytes of tupaia with HDV/HBV infection].

OBJECTIVE: To investigate the relationship between Fas and ICE expression and HDV infection. METHODS: HDAg, Fas, and ICE were determined in 45 liver tissue specimens of tupaia with HDV/HBV infection by immunohistochemistry. RESULTS: Fas was detected in 39 out of 45 liver tissue specimens (86.7%), and ICE in 43 (95.6%). Fas and ICE were located in the cytoplasm or/and the membrane of hepatocytes, especially in the cytoplasm. There was significant correlation between the expression of HDAg and the expression of Fas and ICE (chi(2)=29.2 and 36.2, respectively, P<0.01). CONCLUSIONS: The expression of Fas and ICE may be induced by HDAg in hepatocytes.

Animals↗
PubMed2001

Asymmetric object substitution masking.

Object substitution masking occurs when a lateral mask persists beyond the duration of a target, reflecting reentrant processes in vision (V. Di Lollo, J. Enns, & R. Rensink, 2000). The authors studied whether substitution masking is location specific and whether it is symmetric around the target. A brief circular display of letters was presented along with a mask that designated the target. The mask was centered on the target or 1.1 degrees to the central or to the peripheral side. Substitution masking was found even when the target and the mask were at different locations. It was asymmetric and stronger when the mask was to the peripheral side of the target than to the central side. Asymmetric substitution was observed using various masks. It could not be explained by retina acuity gradients and was not attenuated by focused attention. The authors propose that target selection triggers an asymmetric inhibitory surround that is stronger toward the central side of the target.

Adolescent↗
PubMed2001

[Inhibitory effect of gelsemium alkaloids extract on hepatic carcinoma HepG2 cells in vitro].

The inhibitory effect of gelsemium alkaloids exstract (GAA) on HepG2 cells in vitro were studied by crystal violet dyeing method. The morphological change of HepG2 cells were observed with optical microscope. The alterations of cell cycle induced by GAA were analyzed with flow cytometry. The results showed that HepG2 cells exposed to GAA 10 micrograms/ml was inhibited significantly (P < 0.05). The inhibitory effect appeared in a dose- and time-dependent manner. HepG2 cells showed nuclear chromosome segmentation and condensation after GAA treatment. There emerged obvious Sub-G1 peak in the DNA histogram of HepG2 cells. GAA has a significant inhibition on HepG2 cells in vitro. The mechanism of antitumor action may be related to their apoptosis inducing activity.

Alkaloids↗
PubMed2001

[Protective effect of tanshinone IIA on acute hepatic injury in mice].

OBJECTIVE: To study the effect of tanshinone IIA on two models of acute hepatic injury in mice. METHODS: Two acute hepatic injury models induced by carbon tetrachloride (CCl4) and D-galactosamine (D-GalN) in mice were used. ALT, AST in serum and MDA in liver homogenate were used as indexes. RESULTS: Tanshinone IIA (10 mg.kg-1, 20 mg.kg-1, 30 mg.kg-1), similar to biophenyldicarboxylate, could decrease ALT, AST in serum and MDA in hepatic homogenate on acute hepatic injury induced by CCl4 and D-GalN. CONCLUSION: Tanshinone IIA possessed obvious protective effect against liver injury induced by CCl4 or D-GalN.

Abietanes↗
PubMed2001

Cloning a novel mouse Gabarapl2 cDNA and its characterization.

AIM: To clone a novel mouse GABAA-receptor-associated protein like 2 (Gabarapl2) gene, and to analysis its primary function. METHODS: With the aid of computer, the human GABARAPL2 cDNA was used as information probe to search mouse EST database of GenBank for mouse homolog. A series of overlapping EST were found and assembled into an EST contig using Genetics Computer Group (GCG) ASSEMBLY program. The existence of the gene was then identified by experiment. Northern blotting was performed to hybridize [alpha-32P]dATP labeled probe with mRNA of 11 different mouse tissues that had been transferred to the nylon membrane. RESULTS: The novel gene was deposited in GenBank under Accession No AF190644. Its cDNA contained an intact open reading frame and a canonical polyadenylation signal AATAAA followed by polyA. The deduced protein was completely identical to that of human GABARAPL2, and was termed Gabarapl2 by Mouse Gene Nomenclature Committee. The putative protein of Gabarapl2 has a calculated molecular weight of 13 700 and an isoelectric point of 8.56. It was also predicted to contain two protein kinase C phosphorylation sites and one tyrosine kinase phosphorylation site. Northern hybridization showed that Gabarapl2 was expressed as a single 1.35 kb transcript, with high levels in brain, thymus, lung, heart, kidney, and liver, and low in pancreas, testis, small intestine, colon, and stomach. CONCLUSION: A novel mouse Gabarapl2 gene was cloned and identified.

Adaptor Proteins, Signal Transducing↗
PubMed2001

[Sleep-breathing disordered in stable chronic congestive heart failure].

OBJECTIVE: To determine the prevalence and effect of sleep-disordered breathing in patients with stable, optimally treated chronic congestive heart failure. METHODS: Patients with stable, optimally treated chronic congestive heart failure were monitored by polysomnography (Polywin 1000, Respironics Inc.). RESULTS: Patients were divided into two groups. Group I (n = 21) had a rate of apnea and hypopnea (apnea-hypopnea index) of 15 or less episodes per hour; group II (n = 15) had a rate of more than 15 episodes per hour. In group II, the rate varied from 16.8 to 78.8 episodes per hour 42.6 +/- 15.5, in which the obstructive apnea-hypopnea index was 11.1 +/- 8.4 and the central AHI was 31.5 +/- 9.6. Group II had significantly more arousals (36.8 +/- 21.3 compared with 19.4 +/- 11.2 in group I) that were directly attributable to episodes of apnea and hypopnea, lower arterial oxyhemoglobin saturation during sleep [(76.7 +/- 4.6)% compared with (86.5 +/- 2.8)%] and lower left ventricular ejection fraction [(24.2 +/- 8.8)% compared with (31.5 +/- 10.6)%]. CONCLUSIONS: The prevalence of sleep-disordered breathing (mainly periodic respiration or Cheyne-Stokes respiration with central sleep apnea) is high in patients with stable chronic congestive heart failure. The sleep-disordered breathing episodes are associated with severe nocturnal arterial blood oxyhemoglobin desaturation and excessive arousals. Severe untreated sleep-disordered breathing may affect left ventricular function and could contribute to death in patients with congestive heart failure.

Aged↗
PubMed2001

[Carbon equilibrium in Larix gmelinii forest and impact of global change on it].

In order to provide a methodological demonstration for the study of C cycle in forest, the CENTURY model was applied to simulate the C cycle in Larix gmelinii forest and to approach the impact of global change on it. The results showed that the Larix gmelinii forest served as a C sink, with an annual net absorption of 2.65t.hm-2. Climate change and increased atmospheric CO2 concentration benefited for the net primary production (CNPP) and net C absorption capacity of forests in North China. When the atmospheric temperature was increased by 2 degrees C, the gross biomass and NPP of Larix gmelinii forest increased, while soil C content decreased, and the variation of these three indices was bigger when the precipitation was decreased by 20% than increased by 20%, indicating that the limiting factor for the forest growth in this area is atmospheric temperature, while precipitation is abundant or even too much.

Carbon↗
PubMed2001

Activation of NF-kappa B in bronchial epithelial cells from children with asthma.

OBJECTIVES: To determine whether nuclear factor-kappa B (NF-kappa B) is activated in epithelial cells from children with asthma and to understand the role of NF-kappa B in airway inflammation in asthma. METHODS: Bronchial mucosa specimens were obtained from 9 children with asthma and 6 control subjects. NF-kappa B expression in epithelial cells were detected by immunohistochemical examination, and NF-kappa B-DNA binding was measured by electrophoretic mobility shift assay (EMSA). RESULTS: Nuclear expression of NF-kappa B in epithelial cells was observed in the 9 asthmatic children. NF-kappa B-DNA binding was found in 4 asthmatic children (EMSA was performed in 6 asthmatic children). In contrast, both nuclear expression and NF-kappa B-DNA binding were absent in the 6 control subjects. CONCLUSION: These results indicated that NF-kappa B is activated in epithelial cells from asthmatic children and the NF-kappa B activation may be the basis for the increased expression of many inflammatory genes and for airway inflammation in asthma.

Asthma↗
PubMed2001

[Influence of staphylococcal enterotoxin A on immunogenicity of hepatocellular carcinoma cells].

OBJECTIVE: To transduce the gene of staphylococcal enterotoxin A (SEA) into a HCC cell line HHCC and to make the cells to express the molecules of SEA for the purpose of improving the immunogenicity and inducing immune rejection of HCC. METHODS: Construct retroviral vector containing the gene of SEA and transduce it into HHCC cells. Then the integration, transcription and expression of recombinant were analyzed. At last cytotoxicity test of peripheral blood mixed lymphocytes was carried out. RESULTS: We obtained the retroviral vector pLXSN-SEA, transduced into HHCC cells and obtained the HCC cell line that expressed SEA toxin protein. The content of SEA in supernatant was at the level of pg. The cytotoxicity of HHCC transduced with SEA by T lymphocytes was 45.6%, which was higher than that of HHCC (20.7%). The Km value of T lymphocytes against HHCC transduced with SEA and without SEA was 5.18 x 10(4) and 2.92 x 10(5), separately. The difference had statistical significance. CONCLUSIONS: After transducing the SEA gene, although tiny quantity of expression is detected, the cytotoxicity assay proves that the expression of SEA lead to a robust immune response.

Carcinoma, Hepatocellular↗
PubMed2001

[Preliminary study on skeletal muscle derived tumor suppressor].

OBJECTIVE: To investigate the effect of new born rat skeletal muscle conditioned medium (MCM) on proliferation of tumor cells, and its physicochemical characteristics and mechanisms of action. METHODS: The effects of MCM were tested on a variety of cells by MTT assay. MCM was also tested following ultrafiltration, boiling at 100 degrees C and treatment with trypsin. Morphology and apoptosis of the MCM-treated cells were examined. RESULTS: Proliferation of mouse myeloma SP2/0, rat carcino-sarcoma Walker 256, and tumor cell lines of human origin, including leukemia K562 and HL-60, colon adenocarcinoma LS-174-T, prostatic carcinoma PC3-M, and lung adenocarcinoma with low(PLA801-C) and high(PLA801-D) metastatic potential were significantly decreased when cultured with MCM(P < 0.01-0.05) in a dose-dependent manner. The proliferation of normal cells(RGP-2 rabbit joint epiphysial disk cells) was not affected by MCM. Proliferation of the lung adenocarcinoma with high metastatic potential was more susceptible to the growth inhibitory effect of MCM as compared to that with low metastatic potential. On ultrafiltration, the inhibitory activity of MCM existed in the fraction with a molecular weight < or = 10,000. It was trypsin resistant but thermolabile. Apoptosis was not seen but the cytoplasmic membrane of tumor cells was destroyed after cultured in MCM. CONCLUSION: Rat skeletal muscle cells produce low molecular weight tumor suppressor(s) capable of selectively inhibiting tumor cell proliferation in vitro. Its activity is neither species- nor tumor-specific. The skeletal muscle derived tumor suppressor(s) may play a key role in the rarity of tumor metastases in skeletal muscles.

Animals↗
PubMed2001

[The natural history of electrophysiological and magnetic resonance changes of subacute combined degeneration].

OBJECTIVE: To observe the presentations and in the patients with subacute combined degeneration (SCD) changes of electrophysiology (EP) and magnetic resonance image (MRI) before and after treatment and to analyze their values in diagnosis. METHODS: 10 patients received a series of examinations, including clinical neurological functions, serum vitamin B12 and folic acid concentrations, spinal cord MRI, peripheral nerve conduction velocity, sensory evoked potential (SEP) and visual evoked potential(VEP). They were followed up for 3 to 36 months. The changes of spinal cord MRI and SEP before and after the treatment were studied. RESULTS: After Vitamin B12 therapy, all the patients improved,but there were still some abnormalities of SEP left. The lesions could be shown sensitively by EP. The changes of SEP and clinical symptoms correlated with each other. The spinal cord MRIs of most patients showed the lesions objectively, demonstrating primarily long-tape abnormal signals in posterior and lateral columns, iso-intense on T1 and hyper-intense on T2 without contrast. Most lesions were seen at the thoracic cord. The lesions constricted or disappeared when the clinical conditions improved. CONCLUSION: Spinal cord MRI and EP could objectively show the lesions of SCD and the change before and after the treatment. These examinations and the follow-up of disease could be helpful in the diagnosis of SCD.

Adult↗
PubMed2001

[Clinical and pathologic analysis of Sjögren's syndrome with renal impairment: a report of 84 cases].

OBJECTIVE: To further study the renal damage of Sjögren's syndrome (SS) and its clinical and pathologic characteristics with biopsy and recent technology. METHODS: 84 patients of SS with renal impairment from 1993 to 1999 were analyzed by routine, immunoassay, tubular function and biopsy examination. RESULTS: 55 of the 84 cases presented with renal tubular acidosis (RTA), 5 with diabetes insipidus and 3 with hypokalemic paralysis. Glomerulopathy occurred in 22 cases (nephrotic syndrome 12, glomerulonephritis 10) and mild renal failure (RF) was found in 14. 69.1% of the patients had hypergamma-globulinemia. 64.3% and 44.1% of the patients showed positive anti SS-A and anti SS-B. In 37 renal biopsy specimens 21 showed chronic interstitial nephritis (CIN) with extensive lymphoplasmic cell infiltration and tubular atrophy. 10 of the 37 specimens revealed lupus nephritis (LN, type III and IV) and 5 mesangial proliferative glomerulonephritis (MsPGN). With immunofluorescence tests, no positive findings were seen in most of the specimens, but deposition of IgA, IgM or C(3) was seen in some patients. IgG deposits in the interstitial lymphoplasmic cells were found in 1 patient. 25 patients were treated with prednisone combined with cytoxan (CTX). In 14 patients with renal failure, serum creatinine level returned to normal after treatment. CONCLUSION: Renal impairment may be the presenting or predominant feature in SS. The major clinical manifestations are RTA and GN. Treatment with prednisone may decrease the infiltration of lymphoplasmic cells in the interstitium, improve the renal function and correct RTA.

Adolescent↗
PubMed2001

[A 10-year longitudinal study of the progression of destructive periodontal disease in adult and elderly].

OBJECTIVE: To study the progression of destructive periodontal disease in adult and elderly aged 20 to 80. The examinees were followed 10 years to determine whether the rates for progression of periodontal disease were different than the populations in the more developed countries. METHODS: In 1984, at baseline, 587 subjects had been examined and by 1994, 440 of them still available for follow-up study, and 398 persons remained dentate. Tooth mobility, plaque, calculus, gingival conditions, attachment levels, and probing depths on 4 sites of each tooth present were checked and recorded by the same two examiners. RESULTS: All subjects had > or = 2 mm attachment loss over 10-year period. Some teeth, such as mandibular incisors and maxillary molars, had higher progression rate than others. The mean attachment loss rate did not differ significantly between age groups, and were similar to those reported for populations in the more developed countries. CONCLUSIONS: The rate for progression of periodontal disease in this study were not significantly different between the examinees and the populations in more developed countries; and also were not significantly different among the different age groups. The causes of destructive periodontal disease in humans are more likely intrinsic factors.

Adult↗