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Biomedical subjects

W Z Xu

Publications and source records attributed to W Z Xu.

At least 19 recordsLinked to original sources
PubMed2001

Existence of homologous sequences corresponding to cDNA of the ver gene in diverse higher plant species.

The presence of DNA homologues corresponding to verc203 (vernalization-related cDNA clone) was investigated by molecular hybridization techniques. The genes were detected in 16 plant species that cover 12 subclasses of the Takhtajan system of angiosperms classification including diverse model species. The results of Southern blot analysis showed a low copy number of this gene existed in rice, wheat, barley and Arabidopsis. The hybridization result of PCR products demonstrated the conservation of the gene corresponding to ver203 in diverse plants. The phylogenetic tree of the ver203 gene in tested plants was supported by evolution relationship of species. The ver203 gene expressed in a vernalized plumule winter wheat, instead of the root. And the endosperm before the treatment was essential for the ver203 expression during vernalization in wheat. In Arabidopsis thaliana, the pattern of expression showed that the gene corresponding to ver203 was expressed at low temperature for 14 days. Gibberellin (GA3) may accelerate the expression of ver203 gene in Arabidopsis exposed to low temperature. However, it could not replace vernalization treatment to initiate the gene expression.

Arabidopsis↗
PubMed1995

The impact of dexamethasone on hearing loss in experimental pneumococcal meningitis.

Bacterial meningitis, particularly that resulting from Streptococcus pneumoniae, is a common cause of acquired profound sensorineural deafness in children. The pathogenesis of meningogenic hearing loss has been investigated in an experimental rabbit model. In this study significant deafness was documented within the first 15 hours of infection. Initiation of antibiotic therapy at this time diminished the severity of hearing loss in most animals. The addition of dexamethasone to antibiotic therapy prevented the development of profound deafness. These results suggest this model will be useful in developing antiinflammatory strategies to improve the outcome of bacterial meningitis.

Animals↗
PubMed1994

A new genetically engineered vaccine for animal growth promotion.

The chemically synthesized somatostatin (ss) gene was fused in phase with the 3'-end of hepatitis B virus surface antigen (HBsAg) gene. The fusion gene HBs/ss was then recombined into the genome of vaccinia virus. This recombinant virus (vv-HBs/ss) can express hybrid HBsAg/ss particles which present as determinants on their surfaces, thereby bearing a good immunogenicity. This new strategical vaccine of ss can elicit the production of antibody capable of neutralizing ss in the plasma, and consequently enhance the growth of animals.

Animals↗
PubMed1994

[Effects of shenyan yiqiye on experimental membranous glomerulonephritis in rabbits].

The cationic bovine serum albumin (C-BSA) was used for duplicating experimental animal model of membranous glomerulonephritis with chronic renal failure. Shenyan Yiqiye (SYYQY) was adopted for treatment. The results showed that, in the therapeutic group, the urine protein and serum creatinine were reduced as compared with those in pathological group, P < 0.01. The parameter of morphometric analysis of glomeruli such as mean diameter, mean perimeter, mean surface area, mean volume, mean cross sectional area were all decreased, P < 0.01, the number of glomerular proliferative cells and thickness of glomerular capillary wall were all attenuated, P < 0.01, as compared with those in the pathological group. It suggested that SYYQY might alleviate the glomeruli lesions and benefit the renal functions.

Animals↗
PubMed1993

Progression of hearing loss in experimental pneumococcal meningitis: correlation with cerebrospinal fluid cytochemistry.

The development of hearing loss and concomitant cerebrospinal fluid (CSF) cytochemical changes in a model of pneumococcal meningitis were examined. Rabbits were injected intracisternally with 10(5) pneumococci. Auditory evoked potentials to clicks and to 10- and 1-kHz tone bursts were recorded hourly; CSF was analyzed every 4 h. Sensorineural hearing loss developed in all animals beginning 12 h after infection and progressed to severe deafness. The onset of hearing loss was preceded by a CSF leukocytosis of > 2000 cells/microL and elevation of CSF protein and lactate concentrations to > or = 1 mg/mL. Temporal bone histopathology showed pneumococci and leukocytes extending from the CSF to the perilymph via the cochlear aqueduct. Hearing loss can develop early in the course of meningitis and is preceded by the abrupt onset of inflammatory changes in CSF. Progression of hearing loss is rapid and proceeds from cochlear base to apex in parallel with the degree of inflammation.

Animals↗
PubMed1993

High jugular bulb: implications for posterior fossa neurotologic and cranial base surgery.

The suboccipital-retrosigmoid approach to the internal auditory canal and cerebellopontine angle is being used with increasing frequency for neurotologic surgery, including vestibular nerve section and resection of acoustic neuroma. It offers wide exposure of the cerebellopontine angle and the cranial nerve VII-VIII complex as it courses from the brain stem to the temporal bone. Exposure of the internal auditory canal can be achieved by removing its posterior bony wall. Safe utilization of this approach requires familiarity with the variable position of structures within the petrous bone, including the lateral venous sinus and jugular bulb. We report here a case in which bleeding resulted from injury to a high jugular bulb during surgical exposure of the internal auditory canal via the suboccipital route and discuss the regional anatomy of the jugular bulb based on study of 378 consecutive temporal bone specimens from the collection of the Massachusetts Eye and Ear Infirmary. High jugular bulb was defined as encroachment of the dome of the bulb within 2 mm of the floor of the internal auditory canal. Forty-six percent of scoreable specimens met this criterion. However, when donors less than 6 years of age were excluded, a high jugular bulb was identified in 63% of specimens. Relevance to neurotologic surgery of the posterior fossa is presented.

Adult↗
PubMed1993

Survival of Scarpa's ganglion in the profoundly deaf human.

The electrically evoked auditory brain stem response in some cochlear implant patients may be confounded by evoked potentials generated by vestibular neurons. The magnitude of this contribution to the response from the vestibular system is unknown, in part because the survival of cells within Scarpa's ganglion in profoundly deaf humans is unknown. Therefore, we undertook a quantitative study of Scarpa's ganglion in 48 deaf subjects who in life would have been candidates for cochlear implantation and in 5 subjects with normal hearing. The numbers of residual cells in both Scarpa's ganglion and the spiral ganglion in deaf subjects were significantly less than in individuals with normal hearing. Bivariate analysis demonstrated a highly significant positive correlation between cell counts of Scarpa's ganglion and the spiral ganglion. The durations of hearing loss and of profound deafness were negatively correlated with Scarpa's ganglion cell counts. However, in contrast to spiral ganglion cell survival, the cause of profound deafness did not predict the number of Scarpa's ganglion cells. Multiple linear regression analysis using a variety of clinical parameters demonstrated that the best predictor of the number of Scarpa's ganglion cells in profoundly deaf humans was the number of remaining spiral ganglion cells.

Adult↗
PubMed1992

Diameter of the cochlear nerve in deaf humans: implications for cochlear implantation.

Although the parameters that are most important for postoperative speech perception in cochlear implantation have not been identified, it is assumed that the numbers of remaining cochlear neurons and spiral ganglion cells in the implanted deaf ears are critical. In this study, we evaluated the correlation of the maximum diameter of the cochlear and vestibular nerve trunks with the number of spiral ganglion cells in horizontal sections of the temporal bone of 42 patients who were profoundly deaf during life, and in 5 patients with normal hearing. The maximum diameters of the cochlear, vestibular, and eighth cranial nerves were significantly smaller in the deaf population as compared to normal-hearing controls. In addition, the counts of the remaining spiral ganglion cells were significantly correlated with the maximum diameter of the cochlear (p = .0006), vestibular (p = .001), and eighth cranial nerves (p = .0003). The regression equation estimated that 25% of the variance of the spiral ganglion cell count was predicted by the maximum diameter of the eighth nerve. Although the results of this study suggest that preoperative radiographic imaging of the diameter of the eighth nerve may be helpful in predicting the residual spiral ganglion cell count, the wide variability of diameters of the eighth nerve in hearing and deaf subjects militates against this theoretic usefulness.

Adult↗
PubMed1992

[A laboratory and clinical study of induced differentiation therapy by all trans-retinoic acid in acute promyelocytic leukemia].

According to investigations, it was shown that peripheral blood WBC count increased, percentage of promyelocytes increased, differentiation features emerged, protein kinase C (PK-C) activity elevated, intracellular lysozyme content increased, CFU-F productivity increased and typical t (15; 17) disappeared, when induced differentiation therapy with all trans-retinoic acid (RA) was carried out in patients with acute promyelocytic leukemia. Comparison between RA group and RA+Harringtonin/Ara-C group showed no significant difference in most of the parameters; the curative effect was same in both groups. Complete remission (CR) rate was achieved in 92.6% (25/27 cases) of the patients in the entire group. In order to increase CR rate, prevention and treatment for haemorrhagic complications are critical. Patients with hyperleukocytosis (WBC > or = 100 x 10(9)/L) should be treated with intensive combined therapy as well as aggressive prevention of haemorrhage and pathological changes of lung and brain.

Adolescent↗
PubMed1991

Sequence and properties of beta-xylosidase from Bacillus pumilus IPO. Contradiction of the previous nucleotide sequence.

The nucleotide sequence of the beta-xylosidase (xynB) gene from Bacillus pumilus has been reported previously [Moriyama, H., Fukusaki, E., Crespo, J.C., Shinmyo, A. & Okada, H. (1987) Eur. J. Biochem. 166, 539-545]. However, the sequence identified in the present study is quite different from the previously reported one. The total length of the PstI--EcoRI fragment of a plasmid pOXN295 containing the xynB gene is 2201 bp from our sequencing, while the length of the fragment in the previous data was 2466 bp. The sequences are similar in the N-terminal (500 bp) and C-terminal (260 bp) regions, but those in the central region are completely different. From the following observations, the previous sequence seems to have no reliable experimental basis. First, the restriction sites observed for pOXN295 are quite different from the sites deduced from the sequence. Second, the amino acid composition deduced from the sequence and the composition identified by amino acid analysis of the purified beta-xylosidase are very different. It is confirmed, on the other hand, that our new sequence agrees well with these experimental data. The enzyme was purified to homogeneity from Bacillus pumilus and Escherichia coli harboring a hybrid plasmid which highly expresses the xynB gene. The molecular mass of the enzyme was estimated to be 190 kDa by high performance gel filtration chromatography using TSK-G3000SW and 56 kDa by SDS/polyacrylamide gel electrophoresis. The pH optimum was 7.0, and the optimum temperature was 40 degrees C. The Vm value was estimated to be 1.23 +/- 0.14 mukat/mg (or p-nitrophenyl beta-D-xyloside) and 0.14 +/- 0.011 mukat/mg (for xylobiose), while Km was estimated to be 3.9 +/- 0.59 mM (for p-nitrophenyl beta-D-xyloside) and 8.9 +/- 1.19 mM (for xylobiose).

Amino Acid Sequence↗
PubMed1989

[Preliminary study on red cell immune adherence inhibitory activities in serums of myasthenia gravis patients].

The serum inhibitory activities on RBC-C3b receptor rosette of healthy individuals were studied in myasthenia gravis (MG) patients. The serum inhibitory activities appeared in 65% of MG patients. The serum inhibitory activities of generalized type MG were higher than those of ocular type MG. It was also found that the serum inhibitory activities were correlated with the RBC-C3b receptor rosette rate and immune complex (CIC). Furthermore, it was identified that the CIC of MG serums possessed the inhibitory activity on RBC-C3b receptor rosette.

Antigen-Antibody Complex↗
PubMed1989

[A preliminary study on immune complexes in myasthenia gravis].

The levels of circulating immune complex from 43 patients with myasthenia gravis (MG) and 50 normal controls were detected by using ELISA based on bovine conglutinin. The levels of circulating immune complex in MG patients were higher than those in normal controls (P less than 0.01). Although the levels of circulating immune complex in generalized type MG were higher than those in ocular type MG, the difference showed no statistically significant. It was found that the levels of circulating immune complex, both generalized type MG and ocular type MG, were higher than those in normal controls respectively (P less than 0.01).

Adolescent↗