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Biomedical subjects

D Zhao

Publications and source records attributed to D Zhao.

At least 91 records · Page 5Linked to original sources

Design and clinical application of cervical hollow threaded fixator.

OBJECTIVE: Cervical hollow threaded fixator (CHTF) was designed and applied to stabilize the cervical spine following anterior decompression due to cervical spondylosis or acute cervical disc herniation. METHODS: Medical use titanium alloy with no magnetism was made into a hollow threaded structure with holes on the wall of the fixator. Forty-two patients with cervical spondylosis and acute cervical disc herniation were stabilized using the CHTF technique after anterior decompression. X-ray films and CT scans were taken after the operation to observe the stability and fusion rate of the segments. RESULTS: Patients were allowed to walk one day after the operation and were followed up for 6 to 36 months. The operated segments were stable and solid fusion was observed 3-6 months after surgery. CONCLUSIONS: Immediate stability of the operated segments can be obtained using the CHTF technique. Patients were easy to manage after the operation and returned to their jobs in a short time. The CHTF technique is safe and simple to perform and eliminates the complications of an autograft. It may be an alternative to traditional cervical interbody fusion with bone graft.

Adolescent↗

[Remodelling of the spinal canal after thoracolumbar burst fractures: significance of nonoperative management].

OBJECTIVES: To determine the phenomenon of remodelling of the spinal canal after thoracolumbar burst fracture and to investigate the efficacy of nonoperative management. METHODS: A total of 31 patients with thoracolumbar burst fractures, including 7 untreated, 16 treated nonoperatively, and 8 treated operatively, were retrospectively analysed and followed up for 3 to 7 year. The initial and final degrees of neurological deficit and stenotic ratio of the spinal canal were recorded. RESULTS: The stenotic ratio significantly decreased (P < 0.01) from the discharge (range: 12.3% to 74.5%, average: 26.2%) to the final follow-up (range: 5.4% to 46.5%, average: 19.2%), but there were no differences (P > 0.05) of stenotic ratio improvement among the patients untreated, and treated nonoperatively and operatively, or among the patients with different degree of neurological deficit. CONCLUSIONS: Significant remodelling of the spinal canal develops after thoracolumbar burst fractures. Nonoperative management may be taken into account for treatment of neurological intact patients with thoracolumbar burst fractures.

Adult↗

[The clinical features and study on therapeutic effects of fungal keratitis].

OBJECTIVE: To review the clinical features and therapeutic effects of fungal keratitis (FK). METHODS: 110 cases (110 eyes) with the disease were divided into two types: hyphomycetic keratitis in 94 eyes and candida keratitis in 16 eyes. The clinical features and therapeutic effects of the two types were observed and compared. RESULTS: The hyphomycetic keratitis generally had a plant traumatic history. The border of corneal infiltration was not clear with feather edges, and had a tendency to penetrate into the deep stroma of cornea. There were endothelial plaques, hypopyon and bad therapeutic effects. The pathogenicity of cardida keratitis (CK) was related to the local long-term use of glucocorticoid, the fungus seldom expanded into the deep corneal layers and infiltrated into the inner eye. Its therapeutic effects were better. The border of CK was characterized with limitations, and was clear. CONCLUSIONS: The clinical features of the two types are different. The clinical features caused by different or the same pathogenic fungi show great variations. Early diagnoses, correct use of medicine and operation are the key points to increase the curative rate.

Adolescent↗

[Study on vitamin E succinate inducing apoptosis of human gastric carcinoma cell].

The effects of vitamin E succinate (VES) on the growth of human gastric carcinoma SGC-7901 cell were observed in cell culture. The apoptosis of SGC-7901 cell induced by VES was studied by fluorescent staining and flow-cytometry. The results showed that VES (5, 10 and 20 mg/L) could obviously inhibit the growth of gastric carcinoma cell, and it could be the result of inducing apoptosis.

Antineoplastic Agents↗

[Effect of organic tin on the morphology and mechanical properties during polyurethane-urea curing process].

The mechanical properties and morphology of crosslined PUU in bulk quasi-prepolymer process was studied by in situ FTIR. From the quantitative change of carbonyl FTIR spectra, the development of morphology between noncatalyzed and catalyzed polymerization process was discussed in detail. The effect of organic tin concentration on the mechanical properties was investigated. It showed that urea carbonyl splitted many small weak bands at different sites with increasing of organic tin concentration, and the catalyst played an important role in controlling the morphology and mechanical properties. It also showed that the mechanical properties reached extreme value when the rate constant of -NCO/-OH reaction equate the rate constant of -NCO/-OH reaction.

Catalysis↗

Crystal structure of colicin E3 immunity protein: an inhibitor of a ribosome-inactivating RNase.

BACKGROUND: Colicins are antibiotic-like proteins of Escherichia coli that kill related strains. Colicin E3 acts as an RNase that specifically cleaves 16S rRNA, thereby inactivating the ribosomes in the infected cell. The producing organism is protected against colicin E3 by a specific inhibitor, the immunity protein Im3, which forms a tight 1:1 complex with colicin E3 and renders it inactive. Crystallographic studies on colicin E3 and Im3 have been undertaken to unravel the structural basis for the ribonucleolytic activity and its inhibition. RESULTS: The crystal structure of Im3 has been determined to a resolution of 1.8 A. The structure consists of a four-standard antiparallel beta sheet flanked by three alpha helices on one side of the sheet. Thr7, Phe9, Phe16 and Phe74 form a hydrophobic cluster on the surface of the protein in the vicinity of Cys47. This cluster is part of a putative binding pocket which also includes nine polar residues. CONCLUSIONS: The putative binding pocket of Im3 is the probable site of interaction with colicin E3. The six acidic residues in the pocket may interact with some of the numerous basic residues of colicin E3. The involvement of hydrophobic moieties in the binding is consistent with the observation that the tight complex can only be dissociated by denaturation. The structure of Im3 resembles those of certain nucleic acid binding proteins, in particular domain II of topoisomerase I and RNA-binding proteins that contain the ribonucleoprotein (RNP) sequence motif. This observation suggests that Im3 has a nucleic acid binding function in addition to binding colicin E3.

Bacterial Proteins↗

The ASK1 gene regulates development and interacts with the UFO gene to control floral organ identity in Arabidopsis.

Normal flower development likely requires both specific and general regulators. We have isolated an Arabidopsis mutant ask1-1 (for -Arabidopsis skp1-like1-1), which exhibits defects in both vegetative and reproductive development. In the ask1-1mutant, rosette leaf growth is reduced, resulting in smaller than normal rosette leaves, and internodes in the floral stem are shorter than normal. Examination of cell sizes in these organs indicates that cell expansion is normal in the mutant, but cell number is reduced. In the mutant, the numbers of petals and stamens are reduced, and many flowers have one or more petals with a reduced size. In addition, all mutant flowers have short stamen filaments. Furthermore, petal/stamen chimeric organs are found in many flowers. These results indicate that the ASK1 gene affects the size of vegetative and floral organs. The ask1 floral phenotype resembles somewhat that of the Arabidopsis ufo mutants in that both genes affect whorls 2 and 3. We therefore tested for possible interactions between ASK1 and UFO by analyzing the phenotypes of ufo-2 ask1-1 double mutant plants. In these plants, vegetative development is similar to that of the ask1-1 single mutant, whereas the floral defects are more severe than those in either single mutant. Interior to the first whorl, the double mutant flowers have more sepals or sepal-like organs than are found in ufo-2, and less petals than ask1-1. Our results suggest that ASK1 interacts with UFO to control floral organ identity in whorls 2 and 3. This is very intriguing because ASK1 is very similar in sequence to the yeast SKP1 protein and UFO contains an F-box, a motif known to interact with SKP1 in yeast. Although the precise mechanism of ASK1 and UFO action is unknown, our results support the hypothesis that these two proteins physically interact in vivo.

Arabidopsis↗

Misexpression of argos, an inhibitor of EGFR signaling in oogenesis, leads to the production of bicephalic, ventralized, and lateralized Drosophila melanogaster eggs.

Epidermal growth factor receptor (EGFR) signaling pathways are frequently involved in generating cell fate diversity in a number of organisms. During anterior-posterior and dorso-ventral polarity in the Drosophila egg chamber and eggshell, EGFR signaling leads to a number of determinative events in the follicle cell layer. A high level of Gurken signal leads to the expression of argos in dorsal midline cells. Lateral follicle cells, receiving a lower level of Gurken signal, can continue to express the Broad-Complex (BR-C) and differentiate into cells which produce chorionic appendages. Misexpression of argos in mid-oogenesis causes the midline cells to retain expression of BR-C, resulting in a single fused large appendage. Evidence that argos can directly repress Gurken-induced EGFR signaling is seen when premature expression of argos is induced earlier in oogenesis. It represses the Gurken signal at stage 5-6 of oogenesis which determines posterior follicle cells and occasionally leads to eggs with anteriors at both ends. We propose that the Gurken signal at stage 9 of oogenesis induces follicle cells to take on two fates, dorsal midline and lateral, each producing different parts of the eggshell and that argos is one of the key downstream genes required to select between these two fates.

Animals↗

Expression of P27kip1 and Ki-67 in pituitary adenomas: an investigation of marker of adenoma invasiveness.

Mirroring the ambiguities noted with other endocrine tumours, histology is a poor predictor of the invasiveness of pituitary adenomas. Accordingly, the proteins p27Kip1 (p27) and Ki-67, which respectively block cell-cycle progression and reflect proliferative activity of cells, were studied immunohistochemically in 123 specimens of pituitary adenomas including 57 clinically verified invasive cases. Only Ki-67 had a significant association with invasiveness; only p27 differed significantly between functioning and nonfunctioning adenomas, with a higher frequency of cell labelling in the former. No relationship between Ki-67 and p27 was obtained. Ki-67 detected by MIB-1 is thus an important marker related to the invasive potential of adenomas, and thereby may be helpful in planning postoperative management of patients with pituitary adenomas.

Adolescent↗

Myofibroblasts in the cirrhotic rat liver reflect hepatic remodeling and correlate with fibrosis and sinusoidal capillarization.

BACKGROUND/AIMS: Myofibroblasts are essential in fibrogenesis during development of cirrhosis. In the present study we stereologically quantitated MFB's and correlated them with fibrosis and sinusoidal capillarization. METHODS: Male SD rats were rendered cirrhotic by chronic exposure to phenobarbital/CCl4, (CIR; n = 16); untreated littermates served as controls (CTR; n = 10). Sinusoidal capillarization was assessed by a multiple indicator dilution technique as previously described. The volume fractions of myofibroblasts and other liver components were estimated by morphometry. RESULTS: Myofibroblasts averaged 15.7 +/- SD 0.7% in CIR as compared to 6.7% +/- SD 0.4% in CTR (p < 0.01). An extra-littoral compartment of myofibroblasts was found in portal tracts and within fibrous septa. In CIR, hepatocytes showed a bimodal distribution of volume fractions, and hepatocyte volume distribution disclosed a mirror image of that of myofibroblasts. Connective tissue was markedly increased in CIR, averaging 13.2 +/- 1.2% in CIR vs. 1.2 +/- 0.3% in CTR (p < 0.0001). Extravascular albumin space--a measure of sinusoidal capillarization--was reduced by 44% in CIR (0.028 +/- 0.017 vs. 0.050 +/- 0.010 ml/g; p < 0.001). The volume fraction of myofibroblasts correlated best with extravascular albumin space (r = -0.84, p < 0.001). Multiple regression analysis selected only extravascular albumin space and connective tissue to be determined by the volume fraction of myofibroblasts (r = 0.923; p < 0.001). CONCLUSION: We conclude that increased myofibroblasts reflect the degree of hepatic remodeling rather than cirrhosis inasmuch as myofibroblast volume fraction inversely reflects that of hepatocyte bimodality. Myofibroblasts form an extra-littoral compartment in this model of CIR and correlate with hepatic fibrosis and sinusoidal capillarization.

Actins↗

Conopeptides from Conus striatus and Conus textile by cDNA cloning.

Conopeptide content in Conus textile and Conus striatus venoms were examined by polymerase chain reaction amplification of alpha-conopeptide cDNA and rapid amplification of 3' cDNA ends of O-superfamily conopeptide cDNA. Two new alpha-conopeptide sequences and six new O-superfamily conopeptide sequences from C. textile, four new O-superfamily conopeptide sequences, and four previously biochemically characterized conopeptide sequences from C. striatus were identified. The results suggest that this cDNA method is rapid and requires less material for the study of conopeptides.

Amino Acid Sequence↗

Trial of antiepilepsirine (AES) in children with epilepsy.

Antieplepsirine (AES) is a new antiepileptic drug (AED) which was originally extracted from a Chinese folk remedy, and is now chemically characterized and synthesized. Its chemical structure is different from those of other available AEDs. Animal experiments involving AES demonstrated significant antiepileptic activity. Only a few clinical studies of AES with open trial have been resorted, none of which were on children. A 6.5 month, add-on, double-blind, placebo-controlled, randomized, cross-over study on AES (10 mg/kg per day) was conducted on epileptic children (aged 1-14 years) refractory to treatment with standard AEDs. The seizure frequency was recorded, and the blood levels of AES and other co-medicated AEDs (phenobarbital, phenytoin, carbamazepine and valproate) were determined. Although not planned, patients or parents were allowed to refuse to cross-over to the alternate therapy. The results were compared to the children who crossed-over as well as for the entire group during the first 3 months of randomized treatment. A total of 58 children entered, but only 34/58 children completed the cross-over study. The 24 children whose parents refused to let them be crossed-over continued the original study treatment (AES or placebo) for the entire 6 months. There was no statistically significant difference in seizure control when the entire group of 58 patients was compared to a parallel study group for the first 3 months of therapy (P = 0.178). There was a significant difference (P<0.01) in seizure control between AES and placebo treatment for the 34 patients who completed the entire cross-over study. No significant changes were seen in the blood level of other AEDs, and no serious acute side effects were observed. The results of the present study indicate the efficacy of AES for epileptic children with refractory seizures.

Adolescent↗

Upregulation of heme oxygenase-1 protects genetically fat Zucker rat livers from ischemia/reperfusion injury.

We examined the effects of upregulation of heme oxygenase-1 (HO-1) in steatotic rat liver models of ex vivo cold ischemia/reperfusion (I/R) injury. In the model of ischemia/isolated perfusion, treatment of genetically obese Zucker rats with the HO-1 inducer cobalt protoporphyrin (CoPP) or with adenoviral HO-1 (Ad-HO-1) significantly improved portal venous blood flow, increased bile production, and decreased hepatocyte injury. Unlike in untreated rats or those pretreated with the HO-1 inhibitor zinc protoporphyrin (ZnPP), upregulation of HO-1 by Western blots correlated with amelioration of histologic features of I/R injury. Adjunctive infusion of ZnPP abrogated the beneficial effects of Ad-HO-1 gene transfer, documenting the direct involvement of HO-1 in protection against I/R injury. Following cold ischemia/isotransplantation, HO-1 overexpression extended animal survival from 40% in untreated controls to about 80% after CoPP or Ad-HO-1 therapy. This effect correlated with preserved hepatic architecture, improved liver function, and depressed infiltration by T cells and macrophages. Hence, CoPP- or gene therapy-induced HO-1 prevented I/R injury in steatotic rat livers. These findings provide the rationale for refined new treatments that should increase the supply of usable donor livers and ultimately improve the overall success of liver transplantation.

Adenoviridae↗

A comparative study on the treatment of migraine headache with combined distant and local acupuncture points versus conventional drug therapy.

UNLABELLED: According to Chinese medicine, the differential diagnosis of migraine headache may be classified based on the state of the viscera, channels and collaterals. In this study, acupuncture treatment prescriptions combining distant and local acupoints were selected according to the differential diagnosis. Sixty-four patients were divided into two equal groups: one group received acupuncture, and the other group underwent conventional drug treatment. RESULTS: The efficacy rates in the acupuncture and control groups were as follows, respectively: Cure: 75% versus 34.4%, marked improvement: 18.8% versus 28.1%, no effect: 6.3% versus 37.5%. The overall effective rates for the acupuncture and control groups were 93.8% and 62.5%, respectively, indicating a significantly greater effect in the acupuncture group (P < 0.01, x = 13.475).

Acupuncture Therapy↗

[Determination of 5-hydroxytryptamine(5-HT) secretion from activated platelets by high performance liquid chromatography/electrochemical detector].

A method of determination of 5-HT secretion from activated platelets by HPLC/ECD was established. Spherisorb C18 column of 4.6 mm i.d. x 100 mm was used in this experiment. The CV was 4.65%, The linear range was 0.002 5-1 mg/L. This method has the advantages of high speed, high sensitivity; specificity, of requiring a minimum of preparation of samples and of relatively low cost for instrumentation and reagents. It could reflect the activated situation of platelet induced by weak activator and be used in other biological sample.

Blood Platelets↗

[Study on proteins of allele by using the microisoelectric focusing].

Clear protein electrophoresis pattern of single pollen grain from Cucurbita pepo L. was obtained with isoelectric focusing and supersensitive stain technique. The results showed that there were two special distributing protein bands near acidity pole. In species I, the two protein bands were a little near to acidity pole and in species II, that was a little far from acidity pole. In species III, the two protein bands distributed either like species I or like species II and the distributed ratio was 1:1. Moreover, we discuss how to identify relative purity of gene with the sorts of the special proteins.

Alleles↗

Hierarchically ordered oxides

Porous silica, niobia, and titania with three-dimensional structures patterned over multiple length scales were prepared by combining micromolding, polystyrene sphere templating, and cooperative assembly of inorganic sol-gel species with amphiphilic triblock copolymers. The resulting materials show hierarchical ordering over several discrete and tunable length scales ranging from 10 nanometers to several micrometers. The respective ordered structures can be independently modified by choosing different mold patterns, latex spheres, and block copolymers. The examples presented demonstrate the compositional and structural diversities that are possible with this simple approach.

Journal Article↗