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J Chen

Publications and source records attributed to J Chen.

At least 1,063 records · Page 59Linked to original sources
PubMed2000

[Effects of maxillary growth of Wistar rats with bilateral artificial cleft palate after premaxillary orthopedic treatment on expression of proliferating cell nuclear antigen(PCNA)].

OBJECTIVE: Being based on the principle of Latham's appliance, this experiment is designed to detect activity of osteoblasts in the maxillary sutures of Wistar rats with bilateral artificial cleft palate by immunohistochemistry technique, and evaluate the effects of this appliance on the growth and development of the maxilla. METHODS: The animal models of male infant Wistar rats with bilateral cleft palate were made by removing some palatal bones, splitting a "V" gap of 1.5 cm wide at the line between premaxilla and segments of maxilla. A sort of appliances, which could be fixed in the mouth of Wistar rats with bilateral cleft palate for correcting protrusion premaxilla was constructed basing on the principle of Latham's appliance. Then the diferent pathological changes of osteoblast proliferation between the experimental group and the two controlled groups were examined. The jugomaxillary sutrues, temporomalar sutures and sphenoipalatine suture were harvested 7, 14 days after premaxillar orthopedic treatment, followed by 4% paraformaldehyde fixing about 1 hour, demineralization with 15% EDTA and 0.5% paraformaldehyde for 48 hours, distilled water washing for a night, dimethylbenzene transparant dealing, and paraffin wax embeding. Proliferating Osteoblasts in all these sutures were investigated using immunohiostochemical technique with monoclonal antibodies of proliferating cell nuclear antigen (PCNA). RESULTS: Seven days after orthopedic treatment, no significant difference was observed between the experimental group and the two controlled groups. While after fourteen days, obvious PCNA-positive expression were observed in cells of all these sutures of the experimental group. CONCLUSION: The distribution of proliferating cells and the degree of cell proliferation change after premaxillary orthopedic treatment. And significant cell proliferation is observed in the experimental group, but there are no significant differences between the two controlled groups.

Animals↗
PubMed2000

[Cephalometrical analysis of effects of premaxillary orthopedic treatment on maxillary growth of Wistar rats with bilateral artificial cleft palate].

OBJECTIVE: To measure the differences between the experimental group and the two controlled groups by using the cephalometric radiography technique to study the effects of premaxillary orthopedic treatments on the growth and development of maxilla. METHODS: To make an animal model with bilateral cleft palate by surgery operation: General anesthesia was carried on by injecting 2.5% pentobarbital (25 mg/kg) into abdominal cavity, then almost the same bone of rats' palate were removed from bilateral palate. An appliance, based on the principle of Latham's appliance was made and designed for premaxillary orthopedic treatment. It was fixed in rats' palate using pins under the condition of general anesthesia. After 20 days of orthopedic treatment, the rats were anesthetized by ether, and cephalometric films were taken under self-designed cephalometer and analysed aided by computer. RESULTS: The distances that represented the maxillary position in the posterior-anterior (PA) direction significantly increased (P < 0.05), while the angles that represented the direction of premaxillary growth significantly decreased (P < 0.05) between the experimental group and the two controlled groups. There were no significant difference between the two controlled groups. CONCLUSION: Premaxilla of rats can be effectively moved backward and rotated downward and backward on the PA direction by appliance. The appliance can move the segment palate forward during the premaxillary backword. The appliance can stimulate maxillary growth.

Animals↗
PubMed2000

[Metabotropic glutamate receptors and its contribution to the mechanisms of pain].

Metabotropic glutamate receptors (mGluRs) is a novel family of G protein-coupled receptors. Each subtype shows different features in the aspects of molecular biology, neuropharmacology and distribution in the central nervous system. It can be divided into three groups according to the extent of sequence homology. Recent experimental research has demonstrated that mGluRs play an important role in the transmission of pain. This article will review the possible roles of mGluRs in the processing of nociceptive information.

Animals↗
PubMed2000

[Electron spin resonance studies on the oxidative denaturation of hemoglobin of blood preserved at 20 degrees C].

In order to further understand the injurious change of erythrocytes during blood preservation at room temperature, we studied the denaturation of oxidative hemoglobin of blood preserved at 20 degrees C using electron spin resonance (ESR) technique. The results showed: when blood was preserved at 20 degrees C, there was ESR absorption of low spin hemichrome (g = 2) during the 204-hour preservation period; when the blood was preserved at 4 degrees C after it had been preserved at 20 degrees C for 24 hours, there were ESR absorption of the high spin methemoglobin (g = 6) and ESR absorption of low spin hemichrome (g = 2) during the 40-day preservation period. This study demonstrates that ESR absorption will increase when preservation time increases. When blood is preserved at 4 degrees C, no ESR absorption will emerge during 40 days' preservation.

Adult↗
PubMed2000

[The important role of vitamins in the over-production of pyruvic acid].

The effect of nicotinic acid, thiamine, pyridoxine, biotin and riboflavin on the production of pyruvic acid by Torulopsis glabrata WSH-IP303 with glucose as carbon source and NH4Cl as sole nitrogen source was investigated. By using orthogonal experiment method, thiamine was confirmed to be the most important factor affecting the production of pyruvic acid. Based on a certain concentration range of thiamine (0.01-0.015 mg/L), glucose consumption rate can be enhanced by increasing the concentration of nicotinic acid. When the concentration of nicotinic acid, thiamine, pyridoxine, biotin and riboflavin were 8, 0.015, 0.4, 0.04 and 0.1 mg/L, respectively, the concentration and yield to glucose of pyruvic acid reached 52.4 g/L and 0.525 g/g at 48 h in flask culture, respectively. Batch culture was conducted in a 2.5 L fermentor with initial glucose concentration of 120 g/L. By adopting the optimal concentration combination of vitamins, the concentration and yield to glucose of pyruvic acid reached 69.4 g/L and 0.593 g/g at 57.5 h, which were increased by 32.4% and 13% than the best results in flask culture, respectively.

Ammonium Chloride↗
PubMed2000

[The key enzymes of metabolisms of glycerol in Candida glycerolgenesis].

The specific enzymes for glycerol formation and dissimilation in Candida glycerolgenesis were studied. C. glycerolgenesis hardly assimilated glycerol without glucose and a little amount of glucose remarkably stimulated this dissimilation pathway and the activity and expression of mitochondrial glycerol-3-phosphate dehydrogenase was induced strongly by glycerol-3-phosphate and repressed by glucose metabolism. During glycerol production fermented by C. glycerolgenesis, the activity of cytoplasmic glycerol 3-phosphate dehydrogenase maintained at a higher level and existed two peaks of activity, which appeared at 36 h and 60 h, respectively. The activity level of the first activity peak determines glycerol productivity and becomes a key enzyme of glycerol formation. The activity of glycerol 3-phosphatase maintained at a higher level just between 18 h and 48 h and appeared on peak activity at 36 h. In that period, the activity of glycerol 3-phosphatase was up to more than two times of cytoplasmic glycerol 3-phosphate dehydrogenase and that was inosculated with the phase of rapid accumulation of glycerol during glycerol production by C. glycerolgenesis. In the phase of slowly accumulation of glycerol between 48 h and 72 h, the activity of glycerol 3-phosphatase decreased below that of cytoplasmic glycerol 3-phosphate dehydrogenase. So, cytoplasmic glycerol 3-phosphate dehydrogenase is a key enzyme of glycerol formation in the phase of rapid accumulation of glycerol and glycerol 3-phosphatase becomes a more effective factor after glycerol fermentation reached into slowly accumulation phase. In a conclusion, it is a fundamental for C. glycerolgenesis over-producing high level of glycerol that its cytoplasmic glycerol 3-phosphate dehydrogenase maintains at high activity and the activity of glycerol 3-phosphatase is much higher than that of cytoplasmic glycerol 3-phosphate dehydrogenase.

Candida↗
PubMed2000

[Molecular cloning and expression of E2 gene of the Chinese classical swine fever virus(shimen strain) and preliminary studies of its DNA vaccine].

A 1.1 bp fragment of E2 gene of Chinese classical swine fever virus(CSFV) Shimen strain, a standard virulent strain, was amplified by RT-PCR from total RNA of cell cultures infected by CSFV, and cloned into pGEM T vector. The nucleotide sequence of this fragment was sequenced by Sanger's method and the amino acid sequence was deduced. Compared with the corresponding region of Alfort, Brescia and C strain of CSFV, the nucleotide sequence homology is 84.7%, 92.6% and 95.2% respectively, and the amino acid sequence 89.4%, 92.6% and 94.6%, respectively, we subcloned 1.1 bp of E2 gene cDNA into baculovirus transfer vector and successfully constructed two recombinant baculoviruses expressing GST-E2 and GST-GFP-E2 fusion protein respectively by homologous recombination in sf-9 cell. Furthermore, we also constructed recombinant eukaryotic expression vector pcE2 containing E2 gene in frame and transfected COS-7 cell by lipofectamine, the indirect immunofluorescence assay (IFA) showed that the expressed E2 protein can be recognized by E2 specific monoclonal antibody the pcE2 DNA was directly injected into BALB/c mice intramuscular(i.m.) and the CSFV E2-specific antibodies was measured by enzyme-linked immunosorbent assay(ELISA) the ELISA results indicated the E2-specific antibodies was induced in inoculated mice and virus neutralization assays also indicate single inoculations of plasmids expressing CSFV E2 glycoprotein raised neutralizing antibody in BALB/c mice. these results will be beneficial to investigate the possibility of DNA vaccine against CSFV.

Amino Acid Sequence↗
PubMed2000

[Effects of nitrogen feeding on the accumulation of poly-beta-hydroxybutyrate with Alcaligenes eutrophus].

On the basis of analysis of PHB fermentation processes, the effects of ammonium sulfate feeding rate at PHB formation period on the PHB accumulation by Alcaligenes eutrophus were investigated. It was shown that the complete absence of nitrogen source at PHB formation phase would lead to the decline of PHB synthetic activity, and the obvious influences of different nitrogen feeding rate on PHB synthesis were observed. Higher PHB content, but relative lower cell dry weight, PHB concentration and PHB productivity could be obtained at slower nitrogen feeding rate. The excessive nitrogen feeding rate resulted in the drop of PHB content, which led to the decrease of PHB concentration and PHB productivity. The better results could be achieved when the ammonium sulfate feeding rate was set at around 0.5 g/h.

Ammonium Sulfate↗
PubMed2000

[Cloning of cancer-related genes of Rat6 fibroblasts by using an improved differential display method].

The p53 gene is the most frequently mutated gene identified so far in human cancers. When a mutant p53(135)-val gene was allowed to be over-expressed in Rat6(R6) cells, a high incidence of spontaneous transformation was observed in long-term culture of this cell line(R6 # 13-8). To identify genes involved in cell transformation, parental p53 over-expressing cell, R6 # 13-8, and its spontaneous transformant T2, were analyzed by an improved mRNA differential display technique, which was reproducible, simpler, and was able to clone cDNA longer than 500 bp, and was with less false positives. When 33 10-mer or 12-mer single primers with arbitrary but defined sequence were used for PCR, over 90 discrete cDNAs were obtained from R6 # 13-8 and T2 cells. Three differentially expressed cDNAs were identified, one of them is highly expressed in T2 cells, while the other two, 0.8 kb and 0.9 kb long, are highly expressed in R6 # 13-8 cells. The latter were cloned and confirmed by Northern hybridization. Both cloned fragment were not homologous with any published sequence. Our results suggest that the activation and inactivation of genes are involved in the process of the spontaneous transformation from R6 # 13-8 to T2.

Animals↗
PubMed2000

[Effects on vestibular function by irradiation in the patients with nasopharyngeal carcinoma].

OBJECTIVE: To investigate effects on vestibular function by irradiation in the patients with nasopharyngeal carcinoma. METHOD: Twenty patients with nasopharyngeal carcinoma were routinely irradiated with dose of 70 Gy (3 cases > 70 Gy). RESULT: Nine cases (45%) were abnormal in vestibular function test after radical irradiation in 20 cases (spontaneous nystagmus n = 3; unlateral canal paresis n = 4; bilateral canal paresis n = 2; bilateral vestibular function absent n = 2). The other 11 cases(55%) were normal in vestibular function test. CONCLUSION: Vestibular function may be damaged after radical irradiation in patients with nasopharyngeal carcinoma. During professional identification, this factor must be respected and vestibular function, cochlear function and tubal function must be separately evaluated.

Adult↗
PubMed2000

[Cloning and sequence analysis of a gene encoding amastin from Leishmania major].

OBJECTIVE: To clone a gene encoding surface protein from Leishmania major. METHODS: Using T. cruzi amastin DNA sequence as a reference, computer search was done on GenBank and dbEST databases by using BLAST path. A Leishmania major DNA library has been constructed and screened by in situ colony hybridization. RESULTS: A 309nt DNA fragment from Leishmania major was found in dbEST. Leishmania major DNA library was screened using specific primers synthesized according to 309 nt DNA sequence, and a full-length coding sequence for Leishmania major amastin was cloned. The coding sequence consisted of 552 nt, and translated into 183 amino acid residues. The homology is 23.5% at amino acid sequence level between Leishmania major and T. cruzi amastins. CONCLUSION: A full length amastin coding gene for Leishmania major has been cloned.

Amino Acid Sequence↗
PubMed2000

[Experimental study on decoctum Agrimonia pilosa Ledeb-induced apoptosis in HL-60 cells in vitro].

In this study, MTT assay, cell morphology and flow cytometry were used to explore Agrimonia pilosa Ledeb on HL-60 cells in vitro. The data suggested that Agrimonia pilosa Ledeb had the effects of growth inhibition in HL-60 cells. After treated with decoctum Agrimonia pilosa Ledeb, cells underwent apoptosis with typical morphological feature. DNA histograms by flow cytometric analysis displayed distinct apoptotic peak.

Agrimonia↗
PubMed2000

[Determination of glycyrrihizin in rats plasma and pharmacokinetics after oral administration of si-jun-zi-tang].

OBJECTIVE: To study the pharmacokinetics of glycyrrhizin after oral administration of Si-jun-zi-tang in rats and provide the experimental evidences for the prescription pharmacokientics of traditional Chinese medicine. METHOD: A RP-HPLC method was established for rapid determination of glycyrrhizin in rats plasma. After obtaining the blood sample at different time, the plasma concentration of GL were detected respectively. The data were processed by the software named 3P87 to find the pharmacokinetic parameters. RESULTS: A good linear relationship existed in the range of GL from 1.224 micrograms/ml to 38.656 micrograms/ml. Whole blood concentration-time course of GL after oral administration Si-jun-zi-tang was fitted to be a two-compartment model. GL in rats plasma which came from Si-jun-zi-tang was absorbed and distributed rapidly, but excreted slowly. CONCLUSION: This RP-HPLC method was sensitive, raliable and rapid, it can be used in absorption and metabolism of GL, also in detection of GL preparation. This experiment is prepared for further study of the tradtional Chinese medicine prescription pharmacokinetics.

Administration, Oral↗
PubMed2000

Microsurgical treatment of Mooren's ulcer.

OBJECTIVE: To evaluate effect of microsurgery of lamellar keratoplasty (LKP) on Mooren's corneal ulcer. METHODS: The effect, postoperative astigmatism, postoperative vision, ulcer recurrence of postoperation, and surgical complications of two groups of consecutive Mooren's ulcer inpatients treated respectively by non-microsurgery of LKP and microsurgery of LKP were analyzed. RESULTS: There were significant differences of the effect, postoperative astigmatism, postoperative vision, ulcer recurrence of postoperation, and surgical complications between the two groups. The effect and postoperative vision of the microsurgery-treated group were better than those of the non-microsurgery-treated group. The postoperative astigmatism, ulcer recurrence of postoperation, and surgical complications of the microsurgery-treated group were less than those of the nonmicrosurgery-treated group. CONCLUSION: Microsurgery of LKP of Mooren's corneal ulcer can greatly improve the ulcer healing and postoperative vision, and reduce the surgical complication and the ulcer recurrence of postoperation.

Adolescent↗
PubMed2000

[Shunt tube implantation combining amniotic membrane transplantation and implantation of Molteno implant for glaucoma after penetrating keratoplasty].

PURPOSE: To investigate the therapeutic effect of aqueous humor shunt implants with amniotic membrane transplantation on intractable glaucoma. METHODS: Glaucoma was induced in rabbits by the injection of alpha-chymotrypsin into the posterior chamber of the eyes. The rabbits were divided into four groups. Group A: control group, Group B: single shunt tube group, Group C: shunt tube with amniotic membrane transplantation group, Group D: shunt tube with amniotic supporter and amniotic membrane transplantation group. The intraocular pressure(IOP), histology and filterable ability of the tissue around the tubes were studied. The therapeutic effect of the three methods for the glaucoma was compared. From 1998 to 1999, 42 eyes of 41 patients with uncontrolled glacoma after penetrating keratoplasty were randomly assigned into two groups. One group (12 eyes) underwent implantation of shunt tube combining transplantation of amniotic membrane. The other group underwent implantation of a single plate Molteno implant. Clinical records were reviewed to ascertain postoperative IOP, visual acuities, number of medications. RESULTS: The IOP elevated after the operation and reached at the peak on the third day for all groups and then dropped slowly. The IOP was 33.34 +/- 5.54 mmHg (1 mmHg = 0.133 kPa) for Group A and 27.88 +/- 8.86 mmHg for Group B three months after the operation. There was no statistical difference between the two groups (P = 0.274). The IOP was 22.33 +/- 3.73 mmHg for Group C and there was statistical significant difference between Group C and Group A (P = 0.02) and no difference between Group C and Group B (P = 0.113). The IOP was 15.74 +/- 2.94 mmHg for Group D and there was statistical significant difference between Group D and Group A (P = 0.001) and Group B (P = 0.036). There was no difference between Group D and Group C (P = 0.09). The study of horseradish peroxidase penetrability indicated that there was peroxidase in the tissues around the tube with amniotic membrane transplantation and no peroxidase for simple shunt tube. The fibrous tissue near the tube was denser in simple shunt tube group than that in containing amnion groups. In clinic, the basic data existed no statistical difference between the two groups before surgery. The IOP was 54.42 +/- 9.65 mmHg in shunt tube with amnion group and 43.28 +/- 10.57 mmHg in simple plate Molteno implant group (P = 0.535) before operation. There was significant relativity of the visual acuity before and after the operation in two groups (r = 0.916, P = 0.002 and r = 0.962, P = 0.000). Most patients of the two groups had to use one or two anti glaucoma drugs. The overall success rates were 58.3% for shunt tube with amnion group and 66.7% for Molteno implant group (P = 0.73) within the follow-up period. Kaplan-Meier success analysis indicated one year cumulative success rates of 52.25% for shunt tube with amnion group and of 65.3% for Molteno implant group (P = 0.42). CONCLUSION: Amniotic membrane can inhibit proliferation of the scar around the shunt tube. Shunt tube implantation conbining amniotic membrane transplantation can significantly lowered the IOP of glaucoma. Combined using amnion supporter can expend shunt area and significantly reduce IOP of glaucoma. The effect of shunt tube implantation combining amniotic membrane transplantation has the similar result of single plate Molteno implant for the glaucoma after penetrating keratoplasty.

Adult↗
PubMed2000

[A histochemical and immunohistochemical study of cornea and adjacent bulbar conjunctiva in Mooren's ulcer].

OBJECTIVE: To investigate immunopathologic changes of cornea and adjacent bulbar conjunctiva in Mooren's ulcer, and roles of macrophage, T lymphocyte, and VCAM-1 in the pathogeny of Mooren's ulcer. METHODS: The specimens of the cornea lesions and their adjacent bulbar conjunctiva taken from 18 active Mooren's ulcer cases who received resection of conjunctiva and lamellar keratoplasty surgery were studied with histochemical and labelled streptavidin biotin (LSAB) immunohistochemical techniques to investigate the expressions of CD68, CD3, CD4, CD8, CD1a, VCAM-1, HSP70, and TNF in the affected cornea and adjacent conjunctiva. RESULTS: Under the histochemical examination, infiltration of neutrophils, plasma cells, lymphocytes, and eosinophils were found in the affected cornea and conjunctiva. Degeneration and necrosis of corneal epithelium, Bowman's layer, collageneous fiber in stromal layer, and edema of conjunctiva were shown. Infiltration of a large number of macrophages and T lymphocytes in the affected cornea and adjacent conjunctiva were shown in LSAB immunohistochemical staining. The main infiltrating T lymphocytes were the CD4 positive cells. The CD4/CD8 ratio was significantly higher than that of normal contrals (P < 0.01). VCAM-1 was strongly expressed in the affected corneal and conjunctival epithelium. There were no significant differences for expressions of CD1a, HSP70, and TNF between the pathological specimens and normal contrals. CONCLUSION: The large number of infiltrating macrophages are responsible for the immunopathological damage caused by T lymphocyte infiltration, aberrant production of cytokikens and aberrant expression of HLA-DR antigen of Mooren's ulcer. There is an aberrant expression of VCAM-1 in the affected corneal and conjunctival epithelium. The role of VCAM-1 in the immunopathogenesis of Mooren's ulcer needs to be studied.

Adult↗
PubMed2000

[Descending cervical mediastinitis: report of 15 cases].

OBJECTIVE: To analyze the cause, diagnosis and treatment of descending cervical mediastinitis. METHODS: Fifteen cases of descending cervical mediastinitis, which were treated from January 1985 to December 1997, were retrospectively reviewed. There were 10 males and 5 females, ranging in age from 2.5 to 82 years. RESULTS: The cause of descending cervical mediastinitis included odontogenic infection, suppurative tonsillitis, suppurative otitis media (cholesteatoma) complicating Mouret abscess, pharyngeal injury by foreign body and esophageal perforation. Different ways of drainage were adopted. Twelve cases were cured and three died. CONCLUSION: The key to successful management of descending cervical mediastinitis is early recognition, prompt and effective surgical drainage and appropriate antibiotics.

Adolescent↗