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Biomedical subjects

X Zhu

Publications and source records attributed to X Zhu.

At least 595 records · Page 33Linked to original sources
PubMed1996

The role of human leukocyte antigen in susceptibility and clinical manifestations of sarcoidosis.

OBJECTIVE: To investigate the correlation of human leukocyte antigen (HLA) with susceptibility and clinical manifestations of sarcoidosis. MATERIAL AND METHODS: Fifty-five patients with sarcoidosis and one hundred and six normal subjects were investigated. Genomic DNAs were purified using the proteinase K-phenol extraction method. DNA samples were amplified by the polymerase chain reaction (PCR) procedure using the DRB1 group specific primer pairs. RESULTS: The gene frequency of HLA-DR5 increased significantly in patients with sarcoidosis (P < 0.01), and HLA-DR7 decreased (P < 0.05). Gene frequencies of HLA-DR9 and HLA-DR5 increased remarkably in male patients and in patients with stage I and stage IIa, respectively (both P < 0.05). CONCLUSIONS: It is suggested that HLA-DR gene might contribute to the susceptibility as well as various clinical manifestations of sarcoidosis.

Adult↗
PubMed1996

Observation on solubility and pro-nucleative activity of monoconjugated bilirubin.

OBJECTIVE: To explore the effect of monoconjugated bilirubin (MCB) on gallstone formation of both categories. METHODS: Using a newly established high performance liquid chromatography (HPLC) technique. MCB was extracted, prepared and purified from gallstone patients bile, and its solubility and pro-nucleative activity were observed. RESULTS: In a near physiological environment of biliary tract (pH 7.9 and temperature 37 degrees C), the aqueous solubility of MCB (558.25 +/- 5.96 microns) was only 1/7 of that of disconjugated bilirubin (DCB) (3410.9 +/- 2.42 microns), but 44 times higher than that of unconjugated bilirubin (UCB) (2.43 +/- 0.31 microns) (P < 0.01, between and two of them). Moreover, the solubility of MCB changed curvilineally with the alteration of pH, being highest at pH 7.9, zero at pH 4.5 and even lower than that of ionized UCB at pH above 9. In 3 groups of model bile systems made from Kibe's formula, the nucleation time (NT) was examined by polarized microscopy after 170 microns and 340 microns of MCB was added in group 1 and 2 respectively (group 3 was the control, with no MCB added). The NT was 3.33 +/- 0.52. 2.17 +/- 0.41 and 5.83 +/- 0.75 days respectively in the 3 groups (P < 0.05, between any 2 of the 3 groups) and the nucleative activity (NA) was 0.57 and 0.37 in group 1 and 2 respectively, which confirmed that MCB possessed a dose-related NA which was even stronger than that of glycoprotein (0.56) at the dose of 340 microns. CONCLUSIONS: MCB might play an essential role in the formation and nucleation of gallstones with its poor aqueous solubility and strong pro-nucleative activity via certain lithogenic mechanism.

Bile↗
PubMed1996

Chronic suppurative parotitis: a proposed classification.

OBJECTIVE: To propose a practical and reasonable classification of chronic suppurative parotitis (CSP) on the basis of the various entities. MATERIAL AND METHODS: Clinical, laboratory, sialographic, scintigraphic, histopathologic (including ultrastructural) study of recurrent parotid swellings (RPS) was performed in 291 patients over a 10-year period. RESULTS: It is suggested that CSP should be classified into recurrent parotitis in childhood (RPC), recurrent parotitis in adults (RPA), chronic obstructive parotitis (COP) and should be differentiated from other subdivisions including subclinical Sjögren's syndrome (SCSS), chronic parotid swelling of Sjögren's syndrome and sialadenosis with retrograde infection. RPA is a continuation of recurrent parotid swelling from childhood (RPC) to adulthood. Remission can take place spontaneously in RPC and RPA so that self-conservative therapy is mainly used for reducing the parotid swellings. COP is recurrent parotid swellings and/or purulent discharge resulting from various obstructive factors. Mild COP can recover completely with the use of conservative methods, severe COP is often resistant to conservative treatment and should be treated with surgical modality or injection of methyl violet into the diseased gland. Treatment with methyl violet is considered as a convenient and practical method with a definite effect. SCSS is an autoimmune disease and should be treated as systemic disease. CONCLUSIONS: Because there exists confusion in the nomenclature of RPS this revised classification is based on the various entities and can be used as a guide in the diagnosis and treatment of RPS.

Adolescent↗
PubMed1996

A preliminary study on immune response to hepatitis E virus DNA vaccine in mice.

OBJECTIVE: In order to elicit immune response to hepatitis E virus (HEV) with the method of direct injection of naked DNA. METHODS: The gene encoding the structural protein of pORF3, a Chinese strain of HEV, was cloned into the eukaryotic expression plasmid pSVL. The resulted plasmid pSVL-HEV ORF3 was used as HEV DNA vaccine, to inoculate Balb/c mice intramuscularly with a dose of 100 micrograms. Mice injected with empty pSVL DNA served as control. RESULTS: After 1-2 times inoculation, twelve of 16 mice inoculated with pSVL-HEV ORF3 had anti-HEV IgG seroconversion. pSVL-HEV ORF3 was still detectable in the muscle of the inoculated mice 18 days after the injection, by the method of PCR. None of the control group had a detectable level of anti-HEV IgG. It is also found that the humoral immune response to HEV induced by DNA vaccine could be boostered by HEV recombinant fusion protein. CONCLUSION: Our present study demonstrated that nucleic acid vaccine is able to prime a specific humoral immune response to HEV in mice.

Animals↗
PubMed1996

HLA-DRB1 alleles genotyping in patients with rheumatoid arthritis in Chinese.

OBJECTIVE: To explore the role of HLA-DRB1 genes in the development of rheumatoid arthritis (RA) and the correlations between HLA-DR alleles and clinical manifestations of patients with RA. METHODS: 86 patients with rheumatoid arthritis and 106 race matched controls were studied in whom HLA-DR typing was performed by the method of DNA amplification with sequence-specific primers (PCR-SSP). The subtypes of HLA-DR4 were determined by the method of hybridization of PCR products with sequence-specific oligonucleotides (PCR-SSO). The absence or presence of HLA-DR4 and its subtypes was correlated with the clinical and serological characteristics of the patients. RESULTS: Compared with controls, an increased gene frequency of HLA-DR4 (48.8% vs 17.9%, P < 0.001) and a decreased frequency of HLA-DR7 (16.3% vs 27.4%, P = 0.06) were found. The DRB1* 0405 account for 61.9% of DR4+RA patients and 21.1% of DR4+ controls (P < 0.01). There was no difference between the DR4+ and DR4- patients with respect to age, sex, duration of disease, rheumatoid factor (RF), extra-articular manifestations including secondary Sjogren's syndrome. According to the wrist X-ray stage, the patients of DR4+ were more severe than that of DR4- (P < 0.05). CONCLUSION: HLA-DR4 and DR4 subtype of DRB1*0405 are related to the development of RA in Chinese. HLA-DR4 can be a useful prognostic marker in the patients with RA.

Alleles↗
PubMed1996

[Late result of valve replacement with giant heart].

212 cases of valve replacement with giant heart were followed up for 0.2-15.7 years (mean 3.23 years). There were 21 late deaths. The total survival rate was 91.3%, 80.6%, 74.3% at the 3rd, 6th and 9th year after operation, respectively, and the symptomatic remission rate was 84.4%, 70.6%, 56.8%, respectively. In patients with left atrium and right cardiac enlargement, the survival rate and symptomatic remission rate was significantly higher than those of left ventricle and total cardiac enlargement. The factors influencing late surgical result was discussed.

Adolescent↗
PubMed1996

[Establishment and application of reverse transcription-nested polymerase chain reaction for detection of hepatitis E RNA in serum].

A reverse transcription-nested polymerase chain reaction (RT-nPCR) for detection of hepatitis E virus (HEV) RNA in serum was established using two pairs of oligonucleotide acid from open reading frame 1 and 2 (ORF1 and ORF2) of HEV cDNA as the inner and outer primers. Eleven serial sera from two rhesus monkeys experimentally infected with HEV were tested for HEV RNA with established RT-nPCR. HEV RNA became detectable in these two monkeys on the sixth day and the ninth day, respectively, and persisted up to the 17th and the 22nd day after infection, respectively. Twenty-eight serum specimens of the 41 patients with acute sporadic hepatitis E were HEV RNA positive (68.3%). Proportions of positive HEV RNA in patients sera collected one to ten days, 11 to 20 days and 21 to 34 days after their onset of the disease were 72.7% (16/22), 70.0% (7/10) and 55.5% (5/9), respectively. It suggests that viremia of HEV lasts a shorter period, and proportion of serum positive HEV RNA decreases with the course of the disease.

Animals↗
PubMed1996

[Association of polymorphism in 5'-regulatory region of angiotensinogen gene with essential hypertension].

The association of the variant in the 5'-regulatory region of angiotensinogen gene with primary hypertension in the Han Nationality in China was studied by applying PCR-SSCP analysis and DNA cycle sequencing. The frequencies of three identified SSCP-patterns (pattern-A, B, C) in 73 hypertensive subjects were compared with those in 74 normal controls. It was found that the number of pattern-C was higher in the study group (5/73) than in the controls (1/74). The results of DNA sequencing showed that the difference of three SSCP-patterns was caused by a nucleotide substitution G-->A at -216 locus in the 5'-upstream region of angiotensinogen gene, and the subjects with pattern-C were homozygous for mutant A-allele (genotype A/A). These results suggest that the identified gene variant may be associated with primary hypertension.

Aged↗
PubMed1996

[Repression of voltage gated K+ channel expressed in Xenopus oocytes after injection total RNA from carp retina by an antisense oligonucleotide].

Injection of total RNA from carp retina induced the formation of a membrane K+ channel in Xenopus oocytes. We found an oligonucleotide complementary to the mRNA coding for a peptide fragment in the K+ channel of drosophila and mice could suppress the K+ channel current in a very specific manner. This provides important information for the cloning of this gene and for studying it's function.

Animals↗
PubMed1996

[Studies on glutamate and GABA receptor expressed in amphibian oocytes after injection of carp retina mRNA].

Using voltage clamp and perfusion technique, the types and characteristics of amino acid receptors of carp (Carassius carassius) retinas were studied by expressed response of amphibian oocytes previous injected with the retinal mRNA. The results were as follows: (1) Glu receptor: Diazoxide could potentiated KA induced depolarization, suggesting that some of the retinal Glu receptors may be AMPA-preferring subtype. (2) GABA receptor: Bicuculine could greatly suppress the GABA induced inward rapid current, while GABAB agonist baclofen was without effect. This suggests that the most of retinal GABA receptors may be GABAA type.

Animals↗
PubMed1996

[Sialochemistry in nonneoplastic diseases of parotid gland: immunoglobulins and electrolytes].

The concentration and total value of immunoglobulins (SIgA, IgG) and electrolytes (sodium, potassium, chlorine, calcium and phosphorus) in mixed saliva were examined in 28 patients with Sjögren's syndrome (SS), 25 with chronic obstructive parotitis (COP), 32 with sialadenosis and 32 normal controls. The results showed that in SS group, total saliva flow rate was decreased: concentration of SIgA, IgG, electrolytes was significantly elevated; but total value of SIgA, IgG, electrolytes was markedly decreased. Decreased total value of sodium, potassium, chlorine and calcium was revealed in COP group. Elevated concentration and total value of phosphorus was found in sialadenosis group. This study indicates that examination of total value of immunoglobins and electrolytes has greater value than that of concentration. The possible mechanism of changes observed is discussed.

Adolescent↗
PubMed1996

[The role of human leukocyte antigen in susceptibility and clinical manifestations of sarcoidosis].

To investigate the association of human leukocyte antigen (HLA) with susceptibility and clinical manifestations of sarcoidosis. Fifty-five patients with sarcoidosis were studied by using allele group specific polymerase chain reaction technique (PCR). Our data show that: (1) the gene frequency of HLA-DR5 is significantly increased in patients with sarcoidosis, but that of HLA-DR7 decreased. (2) Gene frequencies of HLA-DR9 and HLA-DR5 are relatively increased in male patients and in patients with stage I and stage IIa, respectively. The results suggest that HLA-DR gene might contribute to the susceptibility as well as to the difference of clinical manifestations in sarcoidosis.

Adult↗
PubMed1996

[Management of coagulation dysfunction in critically surgical patient].

12 surgical critically ill patients were studied for a better management of perioperative coagulation dysfunction. Their primary disease, clinical manifestation as well as some coagulation tests before and after therapy were retrospectively analysed. The result showed that secondary disseminated intravascular coagulation (DIC) is the main type of perioperative coagulation disorder, especially in decompensated hepatopathy and severe sepsis patients. It should be emphasized that: control of primary disease, effective drainage of focus, strict indication for 2nd surgical hemostasis and correct operation are required. For those hepatopathy with hypofibrinogenemia, some hemostatic drugs should be prohibited or very carefully used, in order to avoid the activation of plasmin and the exhaustion of fibrin. The early administration of heparin and aprotinin after the supplement of fibrinogen has shown a great potential benifit to stop the cascade of hypercoagulation and hyperplasminogenemia by enhancing the level of AT-III and fibrinogen in plasma.

Adult↗
PubMed1996

[The effect of MPS on LAK cell growth and its cytotoxic activity against laryngeal cancer (HEP-2)].

IL-2/LAK adoptive immunotherapy is one of new complementary treatments for advanced malignant tumors. This therapy has two main problems: high dose of IL-2 often causes serious side effects and it is difficult to gain enough amount of LAK cells. MPS is a new immunomodulator in cancer immunotherapy. The present study showed that, comparing with IL-2 10(6)U/L only, IL-2 2 x 10(5)U/L plus MPS 0.4mg/L was significantly more effective in activating both the growth of LAK cells and its cytotoxicity against HEP-2 cells. And the ratio of CD25 positive LAK cells cultured in this condition was also higher. This result suggests that MPS plays a role in creasing the membrane receptors of IL-2.

Cell Division↗
PubMed1995

Neuregulin receptors, erbB3 and erbB4, are localized at neuromuscular synapses.

Neuregulin (NRG) is concentrated at synaptic sites and stimulates expression of acetylcholine receptor (AChR) genes in muscle cells grown in cell culture. These results raise the possibility that NRG is a synaptic signal that activates AChR gene expression in synaptic nuclei. Stimulation of NRG receptors, erbB3 and erbB4 initiates oligomerization between these receptors or between these receptors and other members of the epidermal growth factor (EGF) receptor family, resulting in stimulation of their associated tyrosine kinase activities. To determine which erbBs might mediate synapse-specific gene expression, we used antibodies against each erbB to study their expression in rodent skeletal muscle by immunohistochemistry. We show that erbB2, erbB3 and erbB4 are concentrated at synaptic sites in adult skeletal muscle. ErbB3 and erbB4 remain concentrated at synaptic sites following denervation, indicating that erbB3 and erbB4 are expressed in the postsynaptic membrane. In addition, we show that expression of NRG and erbBs, like AChR gene expression, increases at synaptic sites during postnatal development. The localization of erbB3 and erbB4 at synaptic sites is consistent with the idea that a NRG-stimulated signaling pathway is important for synapse-specific gene expression.

Animals↗
PubMed1995

T cell epitope mapping of ragweed pollen allergen Ambrosia artemisiifolia (Amb a 5) and Ambrosia trifida (Amb t 5) and the role of free sulfhydryl groups in T cell recognition.

Ambrosia artemisiifolia (Amb a 5; Ra5S) and Ambrosia trifida (Amb t 5; Ra5G) are homologous allergens purified from short and giant ragweed pollen, respectively. Allergic human sera and hyperimmunized animal antisera directed against Amb a 5 or Amb t 5 show a high degree of species specificity, with little or no cross-reactivity between these two allergens, suggesting that the major Ab binding epitopes of Amb a 5 and Amb t 5 are distinct. Overlapping synthetic peptides derived from the allergen sequences were used to investigate the specificity of T cell responses in four strains of mice, BALB/c (H-2d), CBA (H-2k), C57BL/6 (H-2b), and A/J (H-2a). All four strains of mice responded to purified Amb a 5 and Amb t 5. Cross-reactivity was found at the T cell level between Amb a 5 and Amb t 5 in T cells from BALB/c, A/J, and CBA mice, but not in T cells from C57BL/6 mice. A T cell epitope from Amb a 5, residues 27-36 (PWQVVCYESS), was mapped using T cell hybridomas from BALB/c mice. A T cell epitope in Amb t 5 was mapped in the same strain to residues 24-34 (KYCVCYDSKAI). Disulfide bonds in Amb a 5 and Amb t 5 were found to be involved in T cell reactivity. Conversion of disulfide bridges into free sulfhydryl (SH) forms was required for the response of T cell hybridomas to peptide t5 (residues 27-40) from Amb t 5. Reduction of peptide a4 (residues 21-37) from Amb a 5 was essential for inducing the cross-reactivity observed with Amb t 5-specific T cell hybridomas. It is concluded that free sulfhydryl groups play a major role in the T cell recognition of cross-reactivity T cell epitopes within these related allergens.

Allergens↗
PubMed1995

Catalytic residues of gamma delta resolvase act in cis.

The resolvase protein of the gamma delta transposon is a site-specific recombinase that acts by a concerted break-and-join mechanism. To analyse the role of individual resolvase subunits in DNA strand cleavage, we have directed the binding of catalytic mutants to specific recombination crossover sites or half-sites. Our results demonstrate that the resolvase subunit bound at the half-site proximal to each scissile phosphodiester bond provides the Ser10 nucleophile and Arg8, Arg68 and Arg71 residues essential for cleavage and covalent attachment to the DNA. Several other residues near the presumptive active site are also shown to act in cis. Double-strand cleavage at one crossover site can proceed independently of cleavage at the other site, although interactions between the resolvase dimers bound at the two crossover sites remain essential. An appropriately oriented heterodimer of active and inactive protomers can in most cases mediate either a 'top' or 'bottom' single-strand cleavage, suggesting that there is no obligatory order of strand cleavages. Top-strand cleavage is associated with the topoisomerase I activity of resolvase, suggesting that a functional asymmetry may be imposed on the crossover site by the structure of the active synapse.

Base Sequence↗