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Biomedical subjects

M Chen

Publications and source records attributed to M Chen.

At least 415 records · Page 23Linked to original sources
PubMed1998

[Correction of nasal septal deformities of the unilateral cleft lip].

OBJECTIVE: Septal deformities are very common in patients with unilateral cleft lip nose. The deformities are influential on the morphology of the external nose and respiratory function. The study was conducted to correct the septal deformities. METHOD: The operation procedure includes correction and replacement of the deviated septum to the middle position; correction of the displaced alar cartilage with the suspension method and correction of soft tissue deformities of the nose and lip. Twelve patients were treated with this method from 1994 to 1995. RESULT: Postoperative follow-up of 3-12 months demonstrated satisfactory results. CONCLUSION: Correction of septal deformities plays a very important role in the operation for the unilateral cleft lip nose.

Abnormalities, Multiple↗
PubMed1998

[Study on enzyme-linked immunosorbent assay for cholecystokinin].

This study was undertaken to develop a method for assaying octapeptide cholecystokinin (CCK-8) using ELISA. The design of the method was based on the pretreatment of polystyrene microplates with ultraviolet irradiation and glutaraldehyde activation piror to coating. The results showed that this pretreatment let to stable attachment of CCK-8 to the solid-phase. Competitive ELISA with CCK-8 as a competitor gave excellent quantitive relationship. Using this method we distinguished two kinds of CCK-related peptides. This method proved to be simple, stable and reproducible, the intra- and inter-assay coefficients of variation were 4.75% and 7.80% respectively.

Animals↗
PubMed1998

[Evaluation of body surface ultrasonography in the diagnosis of diseases of abdominal segment esophagus and early-stage carcinoma].

OBJECTIVE: To investigate the possibility of detecting esophageal carcinoma and other lesions by body surface ultrasound (BSUS). METHODS: BSUS examinations of the abdominal segment of the esophagus in 797 subjects were undertaken. Wall thickness more than or equal to 6 mm, wall echo abnormality, and lumen morphologic changes were referred as the criteria of the disease. RESULTS: A visualization rate of 92% (n = 729) was obtained. 716 subjects without any esophageal diseases had a wall thickness of 4 mm or less; Of other 13, one patient had a wall thickness of 5 mm, 11 had 6 mm or more, and one had luminal cystic dilatation without wall thickening. In the 13 cases, the final pathological examination showed 5 cases of esophageal carcinoma (intramucosal, mucosal muscle, submucosal, proper musculature, and serosal patterns, respectively), 2 of metastatic lesion, one of leimyoma, 2 of edematous benign ulcer, one of diverticulum with polyp, and 2 of normal result. CONCLUSION: BSUS can not only detect the early-stage carcinoma, but also further demonstrate wall echo and pathologic changes inside and outside the wall. In the visualization of the submucosal tumor, it is advantage ous to barium examination and endoscopy. With its high sensitivity, simplicity, and non-intervention, BSUS can become a better screening method in everyday practice and in the area with high incidence of esophageal carcinoma.

Adult↗
PubMed1998

[Development of mouse and rat model of Helicobacter pylori infection].

OBJECTIVE: To develop different rodent model of H. pylori infection as to meet different requirement for different purpose of study. METHODS: 40 two-grade Wistar rats, 40 two-grade C57BL/6 mice and 40 SPF BALB/c mice were randomly divided into two groups: experimental and control groups. Animals in the experimental group were inoculated orally Hp strain (Sydney Strain 1, SS1), 0.4 ml of inoculum per mouse, 1.5 ml per rat (10(9) organisms/ml) five times for a week. In 4, 8, 12 and 24 weeks after the last bacteria inoculum, 5 animals in the experimental and control groups were sacrificed respectively. Histology and Hp colonization were assessed by HE staining, Gimesa staining, Urease test, and Hp culture. RESULTS: In 4 weeks, in all experimental animals bacteria were clearly visible at antrum and body, but the number of Hp colonization varied according to the animal strain. Heavy colonization was seen in C57BL/6 in antrum and body, and in BALB/c and Wistar colonization was located mainly at antrum, less at body, which tended to increase over the experiment time, especially in Wistar. Hp was negative in the controls. All animals had no inflammatory changes in 4 weeks, however, in 8, 12 and 24 weeks in Balb/c. Wistar and C57BL/6 of the experimental group, mild to moderate chronic active gastritis was observed in antrum and body, which increased in severity over time, atrophy gastritis was still not seen in 24 weeks. In contrast, in the controls, no remarkable changes were detected. CONCLUSIONS: SS1 Hp can colonize in the glandular stomach mucosa of BALB/c, C57BL/6 mice and Wistar rats and leads to chronic active gastritis in long-term study. SS1 mouse and rat model is adaptable for animal experimentation of H. pylori including vaccine studies, screening for novel therapeutics and investigation of mechanisms of pathogenesis.

Animals↗
PubMed1998

[Effects of glutamate, glutamate receptor in limbic system and hypothalamus on hypothalamus-pituitary-adrenal axis after rats MCAO].

OBJECTIVE: To investigate the features of activity changes of glutamate(Glu), glutamate receptors(GluR) in hippocampus and hypothalamus during rats middle cerebral artery occlusion (MCAO) or reperfusion. METHODS: Using radio-legend binding assay of receptor (RBA), high-performance liquid chromatography (HPLC) and hybridization in situ and radioimmunometric assay, (RIA), we determined the dynamic changes of Glu content, GluR capacity and it's Kd in cell membrane from the hippocampus of the ischemic brain and the hypothalamus CRHmRNA expression levels in every brain areas and ACTH concentrations in plasma at different time after middle cerebral artery occlusion(MCAO) or reperfusion. RESULTS: Glu content rapidly increased in the hippocampus and the hypothalamus at 15 minutes after MCAO, and reached the peak values at I1 h, and rapidly decreased to the basic-line level after reperfusion. Glu content IR24 h to IR48 h, was elevated again moderately, and declined slowly 48 hours after reperfusion. The GluR was down-regulated and the affinity enhanced in during the ischemic period. During the reperfusion period, the GluR was typically up-regulated. The CRHmRNA expressive levels were markedly enhanced in the tempol cortex, the hippocampus and the hypothalamus at I1 h, and kept to IR96 h, the ACTH concentration in the plasma increased relatively. In the peak time of reperfusion, the Glu content of hypothalamus was positively corrected with CRHmRNA expressive positive cell amounts of the hypothalamus. CONCLUSION: CRH may aggravate ischemic neuronal damage, and Glu participates in the pathogenesis of HPA axis be excited strongly and may be an important impel factor for ACI specially condition.

Animals↗
PubMed1998

[ABR feature of medial and old patients with hyperlipidemia].

Sixteen medial and old patients with essential hyperlipidemia who were tested auditory brain-stem response (ABR) with click repetition rate 20/s and 40/s, respectively. In comparison with 12 medial and old people with normallipidemia and 10 health people, the IL and IPL of ABR of the hyperlipidemia group are longer than that of other two groups. There is statistical significant difference among the 3 groups of ABR date. The result showed that the hearing function of the medial and old patients with hyperlipidemia dropped potentially in early phase. Increasing the click repetition rate can improve the detection probability of positive reaction of ABR.

Aged↗
PubMed1998

[Selection of key biological components (KBC) for Controlled Ecological Life Support System (CELSS)].

Biological components are key parts in Controlled Ecological Life Support System (CELSS), the future experimental success will depend to a large extent on the suitability of selected KBCs. For this purpose, 15 KBCs including 4 higher plants(vegetables), 5 microorganisms, 5 microalgae and 1 lower plant were selected from lots of biological species for CELSS. These results laid a solid foundation for our studies of CELSS.

Ecological Systems, Closed↗
PubMed1998

[Thoracoscopic lung reduction surgery for emphysema].

OBJECTIVE: To study the surgical treatment of emphysema. METHOD: Five patients with severe diffused pulmonary emphysema underwent surgical bilateral lung volume reduction by video-assisted thoracoscopy. All patients were male and their age ranged from 60 to 71 years (mean 64.3 years). Before surgery, 5 patients required supplement oxygen with exertion and one oxygen supplement at rest. Preoperative and postoperative assessments included standard pulmonary function studies, chest CT scan and quantitative nuclear lung perfusion and ventilation scan. Wedge resection was performed were in 3 patients, simple plication in 1, and combined wedge resection and plication in 1. There were no early or late mortality and no requirement for immediate postoperative ventilatory assistance. RESULT: Follow-up ranged from 10 to 12 months. After surgery the mean forced expiratory volume in 1 second (FEV(1)) was significantly increased from 0.46 L to 1.13 L (P < 0.001) and the mean forced vital capacity (FVC) was markedly improved from 1.74 L to 2.93 L (P < 0.001). Pulmonary compliance was significantly improved and resistance of airway decreased (P < 0.001). The mean distance during 6-min walk test increased from 10 m to 400 m in 4 patients. CONCLUSION: Thoracoscopic bilateral lung volume reduction is an effective and safe technique for patients with severe emphysema. It can relieve dyspnea and improve in excise tolerance and quality of life.

Aged↗
PubMed1998

[Clinical application of 2 mm micro-thoracoscopic surgery].

OBJECTIVE: To determine the clinical safety and efficacy of micro-thoracoscopic surgery. METHOD: From July 1996 to July 1997, video-assisted thoracoscopic surgery was performed in 47 patients by using 2 mm microthoracoscope. There were 36 males and 11 females. Their age ranged from 40 to 75 years with a mean age of 56.7 years. Surgical procedures included bullectomy (16 patients), wedge resection (3), lung cancer staging (4), lobectomy (2), exploration (15), and resection of mediastinal tumor (2), esophagectomy (1) and repair of pneumothorax (4). Local anesthesia was employed in 18 patients and general anesthesia with double lumen endotracheal tube in 29. RESULT: There were no operative mortality and postoperative complications. CONCLUSION: 2 mm micro-thoracoscopic surgery could be used in the management of a variety of thoracic conditions. It may be of significant value for diagnostic and therapeutic purposes, but the further study for this new technique is required to determine its safety and efficacy.

Adult↗
PubMed1998

[Bio-mechanical property changes of long bone in ovariectomized goats].

This paper presents the biomechanical property changes of long bone in goats at 180 days after ovariectomy. 10 female goats at the age of 1.5 +/- years(average body wight 22 kg) were randomly divided into the control group and ovariectomized group. These goats were sacrificed at 180 days after ovariectomy and the femora, tibiae, metatarsus, humeri, radius and metacarpus were taken out bilaterally. The structural mechanical properties of these bones were measured with the three-point bending method. The material mechanical properties of flexura, compress and tensile in the compact bone specimens taken from the two broken ends were also measured. The results showed that the bone density, bone thickness in broken ends, and the break load of three-point bending for the long bones in the OVX group were obviously lower than those in the control group (P < 0.05). And compared with the control group all the long bones in the OVX group, except the femur, had significantly lower ultimate bending strength, bending elastic modulus; ultimate flexural strength, flexural elastic modulus; ultimate compressing strength, and compressing elastic moduus. Some long bones in the OVX group had significantly decreased ultimate tensile strength (P < 0.05). These indicated that the mechanical properties of long bone in OVX group at 180 days after ovariectomy were reduced in varying degrees and were liable to fracture. This result is in accord with the clinical findings in osteoporosis resulting from post-menopausal estrogen fall and is also consistent with the osteoporotic model of ovariectomized rats. The authors conclude that the bone biomechanical properties are important parameters in assessing osteoporosis and the ovariectomized goat can possible be a good big animal model of osteoporosis.

Animals↗
PubMed1998

[Simulated experiment of hemodynamics changes in aorta during high energetic trauma through abdomen].

In order to study the mechanism of remote effect of missile wound, we designed and carried out a simulated experiment. The change of hemodynamics in aorta was examined with a pressure transducer during gunshot and then calculated. The results revealed superhigh pressure, high speed of pressure rising, accelerated velocity of blood flow, substantial pressure difference and profuse blood flow in aorta during gunshot.

Abdominal Injuries↗
PubMed1998

[A biomechanical evaluation of the effects of XW630 on the healing of experimental fracture].

The aim of this study was to evaluate whether tetracycline-estrone (XW630) plays a role in the healing of fracture. 120 rabbits were divided into 4 groups and subjected to osteotomies at the middle of both radials, and they were given XW630, estrone (E2), tetracycline (T) and 0.9% sodium chloride (C) respectively after operation by means of intramuscular injection (M) or local injection(L) in the fracture region. The biomechanical properties, including bending and compression, and the biochemical changes were tested at 30 days, 60 days and 90 days after osteotomy. The results showed that the bending stress and compression stress in the XW630(M) group were significantly higher than those in other groups at different periods after osteotomy. At 30 days after osteotomy, the bending ultimate stress in the XW630(M) group was 80% higher than that in group C, 76% higher than that in group E2, and 69% higher than that in group T. At 90 days after osteotomy, the bending ultimate stress in XW630(M) group increased to 80% of that of the normal radius, and it was 30% higher than that of group C, 34% higher than that of group E2 and 19.5% higher than that of group T. The biochemical changes corresponded with the changes biomechanical properties. These data suggest that XW630 given by intramuscular injection plays an obvious role in accelerating the healing of fracture. The medicine given by intramuscular injection is obviously more effective than that locally injected.

Animals↗
PubMed1998

[Cloning and sequence analysis of rOmpA gene fragment of spotted fever group Rickettsiae isolated in China].

Rr 190.70 p-602 n primers were used to amplify the rOmpA gene fragment of prototype strains (Rickettsia sibirica 246 strain and R. parkeri) and Chinese strains (BJ-90, Ha-91 and HLJ-054) of spotted fever group rickettsiae (SFGR). The PCR products were cloned into pGEM-T vector respectively and sequenced by Sanger's dideoxy method. The sequences of the tested strains were compared with the corresponding regions of prototype and reference strains of SFGR. The results showed that the homology of rOmpA gene fragments of prototype strains varied from 90.06%-96.62% in nucleotide and 83.05%-94.35% in putative amino acid respectively. Compared Chinese strains with prototype and reference strains of SFGR, it was found that the homology of BJ-90 strain and Ha-91 strain with R. sibirica 246 strain was the highest in nucleotide (99.06% and 98.31%, respectively) and in putative amino acid (98.87% and 96.61%, respectively), whereas HL-93 strain and HLJ-054 strain showed higher homology with R. japonica (96.62% and 95.68% in nucleotide, respectively) than others. Among all the Chinese strains, the homology between BJ-90 strain and Ha-91 strain was the highest, 99.25% in uncleotide and 97.74% in putative amino acid. The homology of nucleotide and putative amino acid between HL-93 strain and HLJ-054 strain was 98.12% and 94.92% respectively. The above results indicated that all SFGR so far isolated from different sources seem to be identical or closely related to R. sibirica, except for HL-93 and HLJ-054 strains, which could be considered as new members of SFGR.

Amino Acid Sequence↗
PubMed1998

Effect of cataract surgery on ocular axial length elongation in young children.

PURPOSE: To evaluate the influence of cataract surgery on eyes of children between 1-5 years old. MATERIALS AND METHODS: Forty-seven cases of pediatric cataract, including 31 cases of bilateral congenital cataract and 16 cases of unilateral posttraumatic cataract, were retrospected. Of the 31 cases of congenital cataract, 19 cases (group 1) had undergone cataract extraction with intraocular lens (IOL) implantation, 12 (group 2) had undergone cataract extraction without IOL implantation. Each of them had their two eyes operated separately at an interval of 1 year or longer. Of the 16 cases of posttraumatic cataract, 6 (group 3) had undergone cataract extraction with IOL implantation and 10 (group 4) had undergone cataract extraction without IOL implantation. Mean age at the time of interested surgery was 2.9 years (range from 1.1 to 5.1 years). Ocular axial length of both eyes measured by A-scan ultrasonography before and after the surgery of the earlier operated eye in the congenital groups and the operated eye in the post-traumatic groups was recorded. The elongation of axial length of the earlier operated eye in the congenital groups and the operated eyes in the posttraumatic groups of each case were compared with that of the fellow eye statistically with paired t-test. RESULTS: The mean follow-up was 2.6 years (ranged from 1.0 to 6.4 years). In all the 4 groups, the elongation of axial length between the earlier operated eye and later operated eye in the congenital groups and between the operated and unoperated eyes in the posttraumatic groups of each case was not significantly different (p > 0.05). CONCLUSION: Cataract surgery, either extraction with or without IOL implantation, did not retard axial elongation in children above 1 year old.

Age Factors↗