Biomedical subjects

Q Xu

Publications and source records attributed to Q Xu.

At least 307 records · Page 17Linked to original sources

PubMed1997

[Effects of low-molecular-weight heparin on proliferative glomerulonephritis].

To investigate the effects of LMWH on proliferative nephritis, we randomized 41 patients who had obvious mesangial cell proliferation testified by renal biopsy into 2 groups according to age, course, clinical manifestations and the pathological lesions. The patients in the control group were given steroid, cyclophosphamide and bennazipril, and the patients in the treated group LMWH (fraxiparin) with the dosage of 60 anti Xa IU.kg-1.day-1 besides the medicine used in the control group. We observed a significant decrease in proteinuria and increase in serum albumin in the treated group compared with those in the control group after 4 weeks of treatment (P < 0.05). The improvement of creatinine clearance in the treated group was significant after 8 and 12 weeks treatment compared with that in the control group (P < 0.05). Our data indicated that LMWH can decrease the proteinuria in the patients who have intraglomerular coagulation and proliferative nephritis with various degrees of sclerosis, and it is helpful to relieve nephrotic syndrome. Because the less risk of hemorrhage, LMWH can be used for long-term treatment to prevent glomerulosclerosis and the process of renal function loss without special mornitoring.

Adolescent↗

PubMed1997

[Peri-operative death in patients undergone lung cancer resection].

OBJECTIVE: To ascertain the causes of peri-operative death in patients with lung cancer. METHODS: Five cases died in the peri-operative period in 174 lung cancer patients undergone resection were analyzed. RESULTS: Two cases died from pulmonary edema and/or atelectasis; one died from acute myocardial infarction and ventricular fibrillation; one had sudden death immediately after withdrawal of endotracheal tube; the other one died of brain matastasis and multiple organ failure. CONCLUSION: Cardio-pulmonary complications are the major causes of peri-operative death in lung cancer patients. Appropriate preventive meassures should be taken to reduce operative mortality.

Adenocarcinoma↗

PubMed1997

[Motion control system in BJ14 medical electron accelerator].

A dual computer based control mode was used in 14 Mev medical electron accelerator. The special non-linear velocity transformation method makes the positioning operation very fast and convenient. The independent driving mode of four blades are suitable to clinical uses. A multi-interlock function provides a safe environment for user's operation.

Computers↗

PubMed1997

Behavior and activities in the central nervous system after activation of L-type calcium channels in mice.

The distribution of the immediate early gene c-fos expression in the mouse central nervous system after subcutaneous injection of Bay K 8644 was observed immunohistochemically. Half an hour after injection, c-fos protein (FOS) was expressed in the piriform cortex, sensorimotor cortex, caudate putamen, thalamic paraventricular nucleus and striate cortex, etc. Intense FOS immunoreactive (FOS-ir) cells were seen during 2-4 h after injection. The results suggested that the distribution of FOS-ir cells after subcutaneous injection of Bay K 8644 was coincident with that of L-type calcium channels in the different areas of the CNS. After Bay K 8644 injection, mice appeared seizure-like behavior. The percentage of cells double-labelled by FOS and CaBP immunoreactivities in the observed regions was about 60.2-72.8% in CaBP-ir cells. It suggested that most CaBP-ir cells may have L-type calcium channels.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗

PubMed1997

[Bone mineral content and its influence factors of children aged 0-16 in a city and village].

The radial and ulnar bone mineral content (BMC) was measured by single-photon absorptiometry, and the effects of multiple independent variables on BMC and bone width (BW) were explored using multiple regression analysis in 332 rural and city children aged 0-16 years in Henan province from 1994 to 1995. BMC, BW, BMC/BW and forearm length increased with age increasing, and the BMC in city children aged 0-6 years was higher than that in rural children. Radial BMC was positively related to BW in the measured sites. Age, body weight and height (or length) all had significantly positive and independent effects on radial BMC in both groups. The positive correlation of radial BMC with age was observed, however, the ratio of radial BMC to body weight was negative correlation. The BW in measured site and forearm length increased with ages. After adjusted for body size, there were no significant effects of sex, age and body weight on radial BW except height (length). This study shows that overall body size rather than adiposity is the important factor for bone BMC, so that it is needed to consider several variables, for example, BMC, BMD, BMC/body weight and BMC/age.

Absorptiometry, Photon↗

PubMed1997

[Effects of different form calcium on growth and tissue calcium level in rats].

In order to solve the problem of calcium deficiency and to look for economic and efficient source of calcium, the effects of calcium carbonate, active calcium and calcium lactate on growth, development and tissue calcium level in rats were compared. Fifty-six 3-week old weaning rats were fed with calcium deficient diet (containing vitamin D 500 IU per kg diet) for 3 weeks, and then were divided into four groups randomly with 14 rats in each group, half male and half female. The diet of control group (A) was the basic diet, while the three experiment diets were supplemented with calcium carbonate (B), active calcium (C) and calcium lactate (D) (3000 mg calcium per kg diet), respectively. The experiment term was 12 weeks. The results showed that the body weight and length of calcium supplemented group were significantly higher than that of control group (P<0.05). Among the calcium supplemented groups, no significant differences were observed except the difference of body length between the group D and the group A in female. Calcium deficiency dramatically hindered the development with reduced dietary intake and decreased food consumption efficiency. The calcium levels in plasma, red blood cells and liver were significantly higher in the supplemented groups than that in the control group (P<0.05), however, there was no difference among the supplemented groups. No significant difference of calcium levels in muscle and heart was observed among all groups. Based on needs for reaching the RDA with additional 400 mg/d from present calcium status in Chinese population, the calcium carbonate is the most economic one and the ideal calcium source for supplementation.

Animals↗

PubMed1997

Association of angiotensin-converting enzyme gene insertion/deletion polymorphism with the clinico-pathological manifestations in immunoglobulin A nephropathy patients.

OBJECTIVE: To investigate the relationship between angiotensin-converting enzyme (ACE) gene insertion/deletion polymorphism and the clinico-pathological manifestations in patients with immunoglobulin nephropathy (IgAN). METHODS: A flanking primer pair and an insertion-specific primer pair were used to perform two polymerase chain reactions so as to analyse the insertion/deletion polymorphism of ACE gene. RESULTS: There was a significantly higher genotype frequency for DD genotype in IgAN patients. The frequencies for DD genotype were also higher in those patients with hypertension and/or heavy proteinuria and/or severe glomerular sclerosis (P < 0.05). CONCLUSIONS: We observed a significant association of the deletion polymorphism of ACE gene with renal insufficiency, hypertension and severe glomerular lesions at biopsy. The deletion allele may play a role, at least to some extent, in the deterioration and progression in IgA nephropathy.

Adolescent↗

PubMed1997

Diagnosis and treatment of solid brainstem tumors in adults.

OBJECTIVE: To evaluate the diagnosis and aggressive surgical approach for brainstem tumors. METHODS: A series of 24 adult patients with brainstem tumors were involved. Magnetic resonance (MR) imaging was performed on all patients. Surgical technique, potential risk and management of complications were described. RESULTS: Diagnosis was confirmed by MR imaging and histological examination in all the patients. Tumors were totally or subtotally removed in twenty-two patients. Signs and symptoms were improved in 19 patients on discharge. CONCLUSIONS: Our study shows that MR imaging has an important value for localizing tumors, identifying their nature and selecting appropriate surgical approaches. Most brainstem tumors, except for high-grade gliomas and small ventral tumors, are amenable to an aggressive surgical approach. The favorable results depend upon the appropriate surgical approach, microsurgical technique and intensive care after operation. Total removal can provide both high-quality survival and favorable long-term prognosis.

Adult↗

PubMed1997

Detection of neuroblastoma cells in blood by reverse transcriptase-polymerase chain reaction.

OBJECTIVE: To determine whether circulating tumor cells are present in patients with localized or disseminated neuroblastoma (NB). METHODS: Sixteen pediatric malignant tumor cell lines, including 10 NB, 4 primitive neuroectodermal tumor (PENT), 2 Wilms' tumor and 39 samples (tumor tissue, bone marrow and peripheral blood) from 8 patients with NB, were evaluated by reverse transcriptase-polymerase chain reaction (RT-PCR) using two markers: neuroendocrine protein gene products 9.5 (PGP 9.5) and tyrosine hydroxylase (TH). RESULTS: Analysis of RT-PCR products by agarose electrophoresis demonstrated that in culture cell lines the specificity for NB was highest in TH (9/10 with NB, 3/4 with PNET, 0/2 with Wilms' tumor) and the sensitivity was highest in PGP 9.5 10(-7). PGP 9.5 and TH mRNA were undetectable in the peripheral blood mononuclear cells (PBMNC) from normal children. Expression of these markers in 8 patients with NB at diagnosis and during treatment was found positive in 5 out of 8, all had been proved paralleling with their disease status. Two of the 5 became negative after further treatment. CONCLUSIONS: These systems allow the detection of circulating NB cells with higher sensitivity and specificity. When RT-PCR is clinically used for the detection of NB cells in blood, that both PGP 9.5 and TH should be selected is recommended. The assessment of bone marrow alone might not be used as a single index of tumor dissemination.

Biomarkers, Tumor↗

PubMed1997

Familial occurrence of hemangioblastoma of central nervous system.

OBJECTIVE: To study the familial occurrence of hemangioblastoma of the central nervous system and to search for an effective way to diagnose and manage the disease. METHODS: From 1974 to 1993, six patients with hemangioblastoma with family history underwent surgical treatment at our hospital. Computerized tomography (CT) or magnetic resonance imaging (MRI) technique was used for the diagnoses before operation. RESULTS: Each patient had more than two relatives with hemangioblastoma. Multiple lesions were found in two of the six familial hemangioblastoma cases. All the patients recovered well after operation. So far, no victims have been discovered in the third generation. CONCLUSIONS: The high occurrence rate of familial hemangioblastoma cases suggests an involvement of hereditary factors. We need a long follow-up study on the descendants of familial hemangioblastoma patients. MRI is of diagnostic value in determining the location and nature of hemangioblastoma in both brain and spinal cord. A thorough examination is necessary for hemangioblastoma patients, and microsurgery is important in removing the tumor.

Adult↗

PubMed1997

[HLA-DR typing by standard serology and PCR-amplification with sequence-specific primers: a comparative study].

OBJECTIVE: DNA typing for HLA-DR by polymerase chain reaction with sequence-specific primers (PCR-SSP) compared with standard serology to evaluate the reliability and clinical practicability. METHODS: Double-blind typing for HLA-DR alleles was carried out using DNA typing by PCR-SSP and standard serology by microlymphocytotoxicity technique in 61 donors and 101 recipients of cadaveric transplantation. Matching time, sensitivity, specificity and clinical practicability were compared according to typing results by both methods. RESULTS: All 162 samples were able to be typed by PCR-SSP. A total of 308 alleles were detected (16 DR "blank"). The results of matching were confirmed by analysis with restriction endonucleases and Southern hybridization. The specificity and reproducibility were 100%. HLA-DR typing was performed in 5 hours by PCR-SSP or 20 hours by serology. The discrepancy rate between PCR-SSP and serological HLA-DR typing was 30.2% (35.6% for kidney recipients, 21.3% for donors). The discrepancies consisted of 8 loci being doubtful, 29 antigens being incorrectly interpreted by serology and 20 of serological "blanks" turning out to be definable alleles by the DNA method. CONCLUSIONS: Genotyping for HLA-DR by PCR-SSP offers the advantages of better reagent and sample availability, more rapid and greater accuracy, all of which would warrant that this approach was suitable for clinical practice in organ transplantation.

DNA↗

PubMed1997

[Effects of glycyrrhisin on myocardial ischemia/reperfusion injury of rabbits].

The content of MDA and the activity of creatine phosphokinase (CPK) together with the ultrastructural changes in myocardial tissue were analysed to observe the effects of glycyrrhisin on myocardial ischemia/reperfusion injury in rabbits. The results showed that glycyrrhisin could remarkably reduced the level of MDA and the activity of CPK in myocardial tissue (P < 0.01), and mitigated significantly the myocrdial ultrastructural injury in comparison with ischemia/reperfusion group. It was considered that glycyrrhisin exerted obvious protective effects on myocardial injury induced by ischemia/reperfusion.

Animals↗

PubMed1997

[Activation of L-Arg: no pathway in canine brain by the damage from complete cerebral ischemia-reperfusion].

To ascertain whether complete cerebral ischemia-reperfusion activate L-Arg: NO pathway in canine brain, we anestherized nine adult dogs with ketamine and fentayle and randomly divided into two groups. Four dogs were nonischemic control group. Five dogs were complete cerebral ischemia-reperfusion group, they underwent a 18-minute cardiac arrest, and were resusciatation by standard CPR, supported by intensive care for 8 hours. At the end of each experiment, the parietal cortex was assayed for content of Nitrite and NADPH-positive neurons. Compared with the control group, the contents of Nitrite and NADPH-positive neurons of coxtex in complete cerebral ischemia-reperfusion group increased significantly (P < 0.01). The results suggest that complete cerebral ischemia-reperfusion activate the L-Arg: NO pathway in canine brain, and NO may play an important role in cerebral ischemia-reperfusion injury.

Animals↗

PubMed1996

A new tinman-related gene, nkx2.7, anticipates the expression of nkx2.5 and nkx2.3 in zebrafish heart and pharyngeal endoderm.

The Drosophila homeobox gene tinman and its vertebrate homologs Nkx-2.5 and Nkx-2.3 are critical determinants of cardiac development. We report here the identification of a new tinman-related gene, nkx2.7, as well as orthologs of Nkx-2.5 and Nkx-2.3 in the zebrafish. Analysis of their expression in the developing zebrafish embryo reveals that nkx2.7 transcripts are the first to appear in cardiac mesodermal and pharyngeal endodermal precursors of the anterior hypoblast, anticipating both temporally and spatially the later expression of nkx2.5 and nkx2.3 in these lineages. The preeminence of nkx2.7 in these embryonic lineages is consistent with a key role in cell fate determination, perhaps in part through the induction of nkx2.5 and nkx2.3. The findings provide the first molecular clues as to the spatial organization of endodermal and cardiac mesodermal precursors in the zebrafish hypoblast immediately following gastrulation. They suggest a coordinate role for these three tinman-related genes in the development of the heart and pharyngeal arches, and reinforce the paradigm of gene duplication and subspecialization between Drosophila and vertebrate species. The results provide a framework in which to analyze potential changes in tinman-related gene expression during abnormal zebrafish development.

Amino Acid Sequence↗

PubMed1996

Dynamics of uniformly 13C-enriched cell wall polysaccharide of Streptococcus mitis J22 studied by 13C relaxation rates.

We have studied the dynamics of the motion of a complex polysaccharide having seven sugar residues in the repeating subunit and which is a receptor for lectin interaction in the coaggregation of oral bacteria. Measurements of the longitudinal and the rotating frame relaxation rates and the heteronuclear nuclear Overhauser effects were carried out on a uniformly 13C-enriched sample using pulse sequences chosen to minimize the effects 13C-13C coupling and cross relaxation. T1 and T1 rho measurements both showed single exponential decay for the anomeric carbon atom resonances of the polysaccharide. The results show the polymer to be highly flexible with a hinge at the (1-->6)-linked galactofuranoside residue. Since there is no generally accepted scheme for interpreting polysaccharide dynamics, several different methods of data analysis were used including a reduced spectral density function method as well as several different methods in which a series of isotropically decaying rotational correlation functions are assumed. The different analyses all show that there are differing amounts of internal motion in the different residues of the polysaccharide. One possible interpretation of the data, which uses an extended version of the model-free treatment, indicates that picosecond motion is exhibited to a similar degree by all the residues in addition to a slower motion on the nanosecond time scale whose amplitude is greatest in the hinge region around the (1-->6)-linked galactofuranoside residue in the polysaccharide.

Carbohydrate Sequence↗

PubMed1996

Molecular modeling of the flexible cell wall polysaccharide of Streptococcus mitis J22 on the basis of heteronuclear NMR coupling constants.

A method for constructing conformational models of flexible complex polysaccharides on the basis of NMR data and molecular modeling is described and is applied to a polysaccharide which is a lectin-binding receptor important in coaggregation of oral bacteria. The method involves uniform biosynthetic enrichment of the polysaccharide with 13C which allows accurate measurements of heteronuclear coupling constants from a three-dimensional coupled HMQC-NOESY spectrum. The improved resolution of the 3D spectrum also provides a large number of accurate values of NOE cross peak volumes in a decoupled HMQC-NOESY spectrum. While it was not possible to construct a model for the flexible polysaccharide directly from the NOE data, a model was successfully built from the coupling constant data. Possible values of glycosidic dihedral angles were extracted from the 3JCH data to build models which were evaluated by molecular modeling calculations. A simple average over a linear combination of low-energy conformations was selected which matched the experimental 3JCH data within experimental error. Simulation of the NOE data for this same combination of conformers gave excellent agreement with experimental NOESY data. Molecular dynamics trajectories both with and without coupling constant constraints do not represent the experimental NOE and 3JCH data as well as the linear combination model. While the polysaccharide has some flexibility in the antigenic site, the lectin-binding site, which contains a furanoside with (1-->6)-linkages, provides a more flexible hinge in the polysaccharide.

Carbohydrate Conformation↗

PubMed1996

Changes of serum antibodies to heat-shock protein 65 in coronary heart disease and acute myocardial infarction.

Accumulating evidence indicates the involvement of heat shock proteins (hsp), a family of stress-inducible proteins, in atherosclerosis. For carotid atherosclerosis an association with an increase in hsp65 antibodies has been demonstrated. To investigate whether such antibodies are also associated with coronary heart disease (CHD) and acute myocardial infarction (MI), an age- and sex-matched study with patients suffering from CHD (n = 114) and MI (n = 89) and healthy controls (n = 76) was performed. All study participants (n = 279) were consecutively recruited according to typical diagnostic criteria. Determination of antibody titres to hsp65 was performed by an enzyme-linked immunosorbent assay (ELISA). Hsp65 antibody titres in CHD showed a significant increase compared to the healthy control group (P = 0.029), however, hsp65 antibody titres were found to be significantly lower in acute MI, compared to CHD (P = 0.005). Alteration in hsp65 antibody titres showed no correlation to established cardiovascular risk factors, e.g. serum total cholesterol, LDL-cholesterol, HDL-cholesterol, triglycerides, blood pressure, smoking, alcohol intake and body weight. In conclusion, serum concentrations of hsp65 antibodies were elevated independently in coronary heart diseases and declined in patients with acute myocardial infarction, indicating a possible involvement of the antibodies in the pathogenesis of this disease.

Aged↗

PubMed1996

Efficient introduction of phosphorothioates into RNA oligonucleotides by 3-ethoxy-1,2,4-dithiazoline-5-one (EDITH).

We recently reported on the use of 1,2,4-dithiazolidine-3,5-dione (DtsNH) and 3-ethoxy-1,2,4-dithiazoline-5-one (EDITH) as effective sulfurizing reagents for the preparation of phosphorothioate-containing oligodeoxyribo-nucleotides [Xu et al. (1996) Nucleic Acids Res., 24, 1602-1607]. One challenge in automated solid-phase synthesis of phosphorothioate-containing RNA is to develop sulfurization reagents that are effective in the presence of bulky 2'-OH protecting groups. The present study demonstrates that EDITH is exceedingly effective at low concentrations (0.05 M) and short reaction times (2 min) for the automated synthesis of oligoribonucleotides.

Base Sequence↗