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Biomedical subjects

X Jiang

Publications and source records attributed to X Jiang.

At least 271 records · Page 15Linked to original sources
PubMed1998

Experimental study on intramuscular injection of eukaryotic expression vector pcDNA3- IL-6 on BXSB mice.

OBJECTIVE: To study the role of IL-6 in systemic lupus erythematosis (SLE). METHODS: We constructed eukaryotic expression vector pcDNA3- IL-6 encoding for IL-6 and injected it intramuscularly into BXSB mice. 22 of the 3.5-month-old male BXSB mice were divided into two groups. One group was injected with the pcDNA3-IL-6 100 micrograms per mouse twice at the interval of 20 days. Another group was injected with plasmid pcDNA3 at the same time as control. The ANA and proteinuria were monitored every 10 days, and the IL-6 activity in serum, IgG, C3 deposition and IL-6 expression in kidney detected at the 40th day. RESULTS: IL-6 encoding plasmid had harmful effects on murine SLE with increased ANA level, proteinuria, IgG, C3 deposition and IL-6 expression in kidney, but there was no difference of serum GPT levels between the two groups. CONCLUSION: Excessive production of IL-6 could play an important pathogenic role in SLE. Blocking or reducing IL-6 secretion might be a new therapy for SLE.

Animals↗
PubMed1998

Alterations of oncogenes, tumor suppressor genes and growth factors in hepatocellular carcinoma: with relation to tumor size and invasiveness.

OBJECTIVE: To make a better understanding of the molecular mechanisms involved in recurrence and metastasis of the hepatocellular carcinoma (HCC), some invasion related oncogenes, and growth factors have been investigated. METHODS: The studies were separately carried out, the results of which were summarized in this article with relation to tumor size and invasiveness of HCC. RESULTS: The aberration rates of p53 and CDKN2 in HCC were 45.9% and 36.4% respectively, which were higher in invasive HCC compared with non-invasive HCC. H-ras expression was positive in 29.3% of HCC, which was associated with recurrence and extrahepatic metastasis of HCC. Intralesional injection of H-ras antisense gene markedly inhibited the tumor growth and metastasis of HCC in nude mice. The positive rates of transforming growth factor (TGF)-alpha, epidermal growth factor receptor (EGFR) and c-erbB-2 were 45.7%, 47.1% and 92.3% respectively. The expression of EGFR was closely related to TGF-alpha, which was related to HCC recurrence. But no obvious difference of TGF-alpha or c-erbB-2 expression was found between HCC with and without recurrence, or with and without extrahepatic metastasis. Expression of nm23/tissue inhibitor of metalloproteinase (TIMP)-2 was positively associated with the prognosis of HCC patients (Log-rank, P < 0.001). The alterative rates of above-mentioned genes and growth factors in small HCC were slightly lower than that in large ones, but no significant difference was shown except the p53 mutation. CONCLUSIONS: The p53/CDKN2 mutation, over-expression of H-ras/EGFR, were associated with the invasiveness and recurrence of HCC. H-ras antisense gene might be of potential implication in the control of HCC recurrence and metastasis. Expression of nm23/TIMP-2 was closely related to the prognosis of HCC patients. Biological characteristics remained critical points to the prognosis even in small HCC.

Animals↗
PubMed1998

[MRI observation on Arnold-Chiari I malformation].

Craniocerical junction of 42 patients with Arnold-Chiari I malformation (ACM-1) and 41 normal controls were studied. In addition to the decendent tonsil, all the components in the posterior cranial fossa including the 4th ventricle, oblongata medulla and the sinus confluence of patients with ACM- 1 were decended. Although the spinal foramen magnum anterior -posterior diameter was smaller but not statistically different from the control. The results suggest that the main pathology of ACM- 1 is the shallow and small posterior cranial fossa and the resulted organ decendent as a whole.

Adolescent↗
PubMed1998

[Study on inhibition and prevention of tumor and antioxidative effects of lithium carbonate in tumor bearing mice].

Two Kinds of tumor-bearing mice (hepatoma H22 and sarcoma S180) were administered with lithium carbonate (Li2CO3) for 17 or 10 days (advanced and simultaneous administration), in order to observe the effects of prevention and treatment of Li2CO3 on malignant tumor, as well as the relationship between Li2CO3 and lipid peroxidation in tumor-bearing mice. Meanwhile, we compared the toxic and side effects of cyclophosphamide (CP) with that of Li2CO3. The results showed that Li2CO3 had no significant toxic or side effects with the suggested doses. In the tests of inhibition and prevention of tumor, Li2CO3 could significantly inhibit the grouth of the two kinds of tumor, and increase the activity of superoxide dismutage (SOD) and decrease the contents of Malonyldialdehyde (MDA). In addition, Li2CO3 had no effect on the white blood cells (WBC) and decreased the micronucleus frequency (MNF) in bone marrow polychromatic erythrocytes (PCE), while CP had definite effect of decreasing the WBC and increasing the MNF in the tumor-bearing mice.

Animals↗
PubMed1998

[The value of MRI for diagnosis of recurrence of rectal carcinoma after surgical resection].

OBJECTIVE: To define the possible role of magnetic resonance imaging (MRI) for diagnosis of local recurrence of rectal carcinoma. METHODS: Pelvic MRI scans of 34 patients with rectal carcinoma received surgical resection were reviewed. SE sequence: Axial T1WI, T2WI and sagittal T1WI scanning of pelvis were performed. Two patients had Gd-DTPA enhancement. RESULTS: Of the 34 patients 27 developed recurrence. The major MRI findings were: tumor mass in the sacro-anterior and perineal regions, T1WI with low signal intensity, T2WI with mixed but slightly high signal intensity, and discontinuity or loss of sacro-anterior fat space on sagittal T1WI. Cancer invasion could be detected to urinary bladder in 8 patients, to prostate in 6 patients, to sacrum in 6 patiens. Pelvic lymph node enlargement was seen in 3 patients. Seven patients did not show any signs of tumor recurrence. CONCLUSION: Routine follow-up MRI scan after rectal carcinoma resection is useful in revealing recurrence of cancer and its extent of involvement.

Adult↗
PubMed1998

[Effects of glutamate, glutamate receptor in limbic system and hypothalamus on hypothalamus-pituitary-adrenal axis after rats MCAO].

OBJECTIVE: To investigate the features of activity changes of glutamate(Glu), glutamate receptors(GluR) in hippocampus and hypothalamus during rats middle cerebral artery occlusion (MCAO) or reperfusion. METHODS: Using radio-legend binding assay of receptor (RBA), high-performance liquid chromatography (HPLC) and hybridization in situ and radioimmunometric assay, (RIA), we determined the dynamic changes of Glu content, GluR capacity and it's Kd in cell membrane from the hippocampus of the ischemic brain and the hypothalamus CRHmRNA expression levels in every brain areas and ACTH concentrations in plasma at different time after middle cerebral artery occlusion(MCAO) or reperfusion. RESULTS: Glu content rapidly increased in the hippocampus and the hypothalamus at 15 minutes after MCAO, and reached the peak values at I1 h, and rapidly decreased to the basic-line level after reperfusion. Glu content IR24 h to IR48 h, was elevated again moderately, and declined slowly 48 hours after reperfusion. The GluR was down-regulated and the affinity enhanced in during the ischemic period. During the reperfusion period, the GluR was typically up-regulated. The CRHmRNA expressive levels were markedly enhanced in the tempol cortex, the hippocampus and the hypothalamus at I1 h, and kept to IR96 h, the ACTH concentration in the plasma increased relatively. In the peak time of reperfusion, the Glu content of hypothalamus was positively corrected with CRHmRNA expressive positive cell amounts of the hypothalamus. CONCLUSION: CRH may aggravate ischemic neuronal damage, and Glu participates in the pathogenesis of HPA axis be excited strongly and may be an important impel factor for ACI specially condition.

Animals↗
PubMed1998

[Relationship between helicobacter pylori infection and cirrhosis of liver].

Twenty-five (71.4%) of 35 cirrhotic patients were infected with Helicobacter pylori (Hp), compared with 21 (65.6%) of 32 patients with gastric or duodenal diseases (P > 0.05). The Hp infection rate in patients with liver lesion was higher than that of patients without liver lesion (79.3% and 33.3%, respectively). Ten (83.3%) of 12 patients with hepatic encephalopathy were infected with Hp, compared with 15 (65.2%) of 23 patients without hepatic encephalopathy. The cirrhotic patients have a high Hp infection rate and those infected are at higher risk for hepatic encephalopathy.

Adult↗
PubMed1998

[A study on the induction of mutation of paddy rice under space conditions].

Rice seeds were carried into space by the recoverable satellite. After recovery the seeds were sowed on the earth so as to observe the character performance and genetic variation of their later generations. The preliminary results showed that the main characters of the SP1 generation didn't show significant difference from the control. Among the individual plants of the SP2 generation strong broad-spectrum segregation appeared in the 9 main agronomic characters. Mutation frequency is 4.66%. The individual plants of the SP3 generation were obviously correlated with the SP4 generation in the average character values of the 5 main characters. Stable plant strains were obtained in the SP4 generation. The SP5 and SP6 generations were put into control and polt tests. As a conclusion, it may be considered that certain variations of rice seeds induced by the space conditions are heritable to the offsprings, therefore, it can be used as a new method for mutagenic seed breeding.

Genes, Plant↗
PubMed1998

[Mutation induced by space conditions in Escherichia coli strains].

To study the mutagenesis of microorganism under space conditions, three Escherichia coli strains CSH108, A2 and A3, were flown on board the Chinese recoverable satellite (JB1 - B9611020) in Oct . 1996. Three ways of sample boarding were designed . After recovery, survival and frequency of lacI- mutation and Arg+ reversion were determined in the flight strains. The results showed that: E. coli strains could survive after the flight conditions. The lacI- mutation frequency of A3 strain in the biocabin was sixty - seven times that of the ground control, the Arg+ reversion frequency of CSH108 in the lead chamber, was ten times that of the ground control; and among the revertants the mutation frequency of non-sense suppressor increased remarkably. The results indicate that the space conditions may greatly enhance the mutation frequency of certain genes in the microorganism and may provide an effective method for microorganism breeding.

Arginine↗
PubMed1998

[Exfoliative cancer cells in the surgical field of breast cancer].

OBJECTIVE: To study the relationship between exfoliative cancer cells in the surgical field and pathological stages of breast cancer and provide a theoretical basis for killing or removing of the exfoliative cancer cells in the surgical field. METHOD: Cytological examination of surgical field washings was performed in 104 patients with breast cancer. The results and pathological stages were compared and analysed. RESULT: Exfoliative cancer cells were found in the surgical field washings in 36 of 104 (34.6%). Stage I, II and III showed a positive rate of 3.8%, 29.8% and 85.7%. The positive rate of T(1), T(2) and beyond T(3) were 10.8%, 33.3% and 77.3%, respectively. When the number of axillary metastatic lymph nodes was over four, the positive rate of exfoliative cancer cell was 76.0% and only 13.5% if no axillary lymph node metastasis. CONCLUSION: Killing or removing of the exfoliative cancer cells in the surgical field of breast cancer is necessary.

Biopsy↗
PubMed1998

[Unreamed interlocking intra medullary nailing in treating tibial and fibular fractures].

OBJECTIVE: To report the experience in the use of unreamed interlocking intramedullary nails. METHOD: From 1995 to 1997, 54 tibial and fibular fractures were treated with unreamed interlocking intramedullary nails they included open fractures (9 cases) and close fractures (45). RESULT: All fractures healed within 6 months and showed good knee and ankle joint functions. Slight postoperation infection was found in one of the open fractures. Incomplete injury of peroneal nerve was noted in 1 case. CONCLUSION: Unreamed interlocking intramedullary nail can be used to treat diaphyseal fractures effectively. It can protect the soft tissue envelope around the fracture and prerent local blood supply from further damaginge.

Adolescent↗
PubMed1998

[Study on the rifampicin polylactic acid microspheres for lung targeting].

In this paper, the effects of different variables on the preparation of polylactic acid microspheres (PLA-MS) were studied. The optimized preparation conditions of rifampicin polylactic acid microspheres (RFP-PLA-MS) were aquired through orthogonal test. The paddle method was used to study the drug release properties of RFP-PLA-MS. Stability of RFP-PLA-MS at different temperatures was also studied. Pharmacokinetic and tissue distribution of RFP-PLA-MS after intravenous administration were carried out in rabbits. The experiments revealed that the RFP-PLA-MS was regular in its morphology with a mean diameter of 9.00 +/- 4.08 microns. The drug loading was 16.0% and encapsulation efficiency was 31.9%. The release properties could be expressed by the following equation: Q = 20.77 + 10.12 T 1/2 (gamma = 0.9892). The RFP-PLA-MS was stable after stored at 4 degrees C and room temperature under desiccated condition for three months. RFP-PLA-MS showed a combination of lung targeting and sustained drug release in experiments on rabbits.

Animals↗
PubMed1998

[Sensitivity of cationic polymer Eudragit RL to electrolytes and its effect on drug release from Eudragit RL matrix].

The swelling behavior of acrylic polymer Eudragit RL in different concentration and species of electrolyte aqueous media, and the effect of media and polymer swelling on drug release from Eudragit RL matrix system were investigated with nifedipine, chlorpheniramine maleate and indomethacin as model drugs. It was found that Eudragit RL was sensitive to the electrolytes in aqueous media. The swelling of Eudragit RL decreased with increasing electrolyte concentration and was significantly affected by the electrolyte species. The swelling behavior was reversible. The release of 3 drugs from Eudragit RL matrix was remarkably affected by the electrolytes in the media. The rates of release of nifedipine and chlorpheniramine maleate from the polymer matrices were controlled by the polymer swelling behavior, and the rate of release correlated well with the swelling behavior. However, the rates of release of indomethacin from the Eudragit RL matrix were controlled not only by the polymer swelling but also by the drug displacement by the medium anion, which was attributed to the presence of an interaction between indomethacin and Eudragit RL.

Chlorpheniramine↗
PubMed1998

Homotypic and heterotypic IgG and IgM antibody responses in adults infected with small round structured viruses.

Antibody responses to recombinant Norwalk (rNV) and Mexico (rMXV) viral capsid proteins were studied in 39 adults involved in outbreaks of gastroenteritis associated with genogroup 2 small round structured viruses (SRSVs). Nineteen individuals were involved in outbreaks associated with MXV-like strains and 20 in outbreaks associated with four other genogroup 2 SRSVs. IgG antibodies were measured in acute and convalescent sera using indirect enzyme-linked immunosorbent assay (ELISA), and IgM was measured by indirect and capture ELISAs. Nineteen (49%) patients demonstrated a significant rise in IgG to rMXV with four (10%) patients also showing anamnestic responses to rNV. Fourteen patients were positive in the rMXV IgM-capture ELISA, representing 74% of patients demonstrating IgG rises. IgG and IgM responses to rMXV were observed in both groups, although higher levels of responses were seen in adults infected with MXV-like strains than those infected with non-MXV genogroup 2 viruses. No significant IgM responses were observed to rNV. These results indicate that, following SRSV infection, adults show a rise in antibody which is broadly reactive to viruses within but not between genogroups, although greater homotypic than heterotypic responses are produced. These findings have implications for interpretation of seroepidemiological studies and serodiagnosis of SRSV infections using recombinant capsids.

Adult↗
PubMed1997

Altered pathogenesis of a mutant of the murine coronavirus MHV-A59 is associated with a Q159L amino acid substitution in the spike protein.

C12, an attenuated, fusion delayed, very weakly hepatotropic mutant of mouse hepatitis virus strain A59 (MHV-A59( has been further characterized. We have previously shown that C12 has two amino acid substitutions relative to wild type virus in the spike protein, Q159L (within a region of S1 shown to bind to viral receptor in an in vitro assay) and H716D (in the proteolytic cleavage recognition site). We have sequenced the rest of the 31-kb genome of C-12 and compared it to wild type virus. Only three additional amino acids substitutions were found, all encoded within the replicase gene. Analysis of C12 in vivo in C57Bl/6 mice has shown that despite the fact that this virus replicates in the brain to titers at least as high as wild type and causes acute encephalitis similar to wild-type, this virus causes a minimal level of demyelination and only at very high levels of virus inoculation. Thus acute encephalitis is not sufficient for the induction of demyelination by MHV-A59. Analysis of mutants isolated at earlier times from the same persistently infected glial cell culture as C12, as well as mutants isolated from a second independent culture of persistently infected glial cells, suggests that both the weakly demyelinating and the weakly hepatotropic phenotypes of C12 are associated with the Q159L amino acid substitution.

Amino Acid Substitution↗
PubMed1997

Differences in active site gorge dimensions of cholinesterases revealed by binding of inhibitors to human butyrylcholinesterase.

Amino acid sequence alignments of cholinesterases revealed that 6 of 14 aromatic amino acid residues lining the active center gorge of acetylcholinesterase are replaced by aliphatic amino acid residues in butyrylcholinesterase. The Y337 (F330) in mammalian acetylcholinesterase, which is replaced by A328 in human butyrylcholinesterase, is implicated in the binding of ligands such as huperzine A, edrophonium, and acridines and one end of bisquaternary compounds such as BW284C51 and decamethonium. Y337 may sterically hinder the binding of phenothiazines such as ethopropazine, which contains a bulky exocyclic substitution. Inhibition studies of (-)-huperzine A with human butyrylcholinesterase mutants, where A328 (KI = 194.6 microM) was modified to either F (KI = 0.6 microM, as in Torpedo acetylcholinesterase) or Y (KI = 0.032 microM, as in mammalian acetylcholinesterase), confirmed previous observations made with acetylcholinesterase mutants that this residue is important for binding huperzine A. Inhibition studies of ethopropazine with butyrylcholinesterase mutants, where A328 (KI = 0.18 microM) was modified to either F (KI = 0.82 microM) or Y (KI = 0.28 microM), suggested that A328 was not solely responsible for the selectivity of ethopropazine. Volume calculations for the active site gorge showed that the poor inhibitory activity of ethopropazine toward acetylcholinesterase was due to the smaller dimension of the active site gorge which was unable to accommodate the bulky inhibitor molecule. The volume of the butyrylcholinesterase active site gorge is approximately 200 A3 larger than that of the acetylcholinesterase gorge, which allows the accommodation of ethopropazine in two different orientations as demonstrated by rigid-body refinement and molecular dynamics calculations.

Animals↗
PubMed1997

Interaction between glycosaminoglycans and immunoglobulin light chains.

Amyloidosis is a pathological process in which normally soluble proteins polymerize to form insoluble fibrils (amyloid). Amyloid formation is found in a number of diseases, including Alzheimer's disease, adult-onset diabetes, and light-chain-associated amyloidosis. No pharmaceutical methods currently exist to prevent this process or to remove the fibrils from tissue. The search for treatment and prevention methods is hampered by a limited understanding of the biophysical basis of amyloid formation. Glycosaminoglycans (GAGs) are long, unbranched heteropolysaccharides composed of repeating disaccharide subunits and are known to associate with amyloid fibrils. The interaction of amyloid-associated free light chains with GAGs was tested by both size-exclusion high-performance liquid chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis experiments. The results indicated that heparin 16 000 and chondroitin sulfate B and C precipitated both human intact light chains and recombinant light chain variable domains. Although all light chains interacted with heparin, the strongest interactions were obtained with proteins that had formed amyloid. Molecular modeling indicated the possibility of interaction between heparin and the conserved saddlelike surface of the light chain dimer opposite the complementarity-determining segments that form part of the antigen-binding site of a functional antibody. This suggestion might offer a new path to block the aggregation of amyloid-associated light chain proteins, by design of antagonists based on properties of GAG binding. A hexasaccharide was modeled as the basis for a possible antagonist.

Amyloidosis↗