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Biomedical subjects

Y Ou

Publications and source records attributed to Y Ou.

36 records · Page 2Linked to original sources
PubMed1999

[CAG trinucleotide mutation detection in patients with hereditary spinocerebellar ataxia].

OBJECTIVE: To assess the frequency of the SCA1, SCA2,SCA3/MJD, SCA6, SCA7 and DRPLA CAG trinucleotide repeat expansions(CAG)n among individuals diagnosed with hereditary spinocerebellar ataxia(SCA) from Chinese families. METHODS: The SCA1, SCA2, SCA3/MJD, SCA6, SCA7 and DRPLA(CAG)n mutations were detected by polymerase chain reaction (PCR), denaturing polyacrylamide gel electrophoresis and silver staining technique in 167 patients with autosomal dominant SCA from 85 Chinese families and 37 sporadic SCA patients. RESULTS: Among 85 families, four families(4.70%) had seven SCA1 patients with the CAG repeat expanded to 53 to 62 repeats, five (5.88%) had twelve SCA2 patients with the CAG repeat expanded to 43 to 47 repeats, and 41 (48.23%) had 83 SCA3/MJD patients with the CAG repeat expanded to 68 to 83 repeats. Analysis of the mutation in these families showed a strong negative correlation between the size of the expanded CAG repeat and the age of disease onset. None of the SCA patients were positive for SCA6, SCA7, or DRPLA. Nor was any of the sporadic SCA patients positive for the CAG repeat expansion in the SCA1, SCA2, SCA3/MJD, SCA6, SCA7, or DRPLA gene. CONCLUSION: The frequency of SCA3/MJD is substantially higher than that of SCA1 and SCA2 in the autosomal dominant SCA from Chinese families. Chinese SCA3/MJD patients are non-Portuguese. Clinical expressions of the various SCAs overlap one another and hence can make the phenotype-based diagnostic classification inaccurate in many instances. It is important for SCA clinical studies to make an SCA gene diagnosis and genotype analysis.

Adult↗
PubMed1999

[Comparison of results of chamber angle examination by ultrasound biomicroscopy and gonioscopy].

OBJECTIVE: To compare the consistency of the chamber angles examined by ultrasound biomicroscope (UBM) and gonioscope and provide gonioscopic examination with new methods and technology. METHODS: 10 patients (20 eyes) were selected for the research. The same eyes were examined by UBM and gonioscope in turns. The results from the two methods were compared and the data were analyzed with Spearman correlation test. RESULTS: The results of two methods of chamber angle examination were well consistent when the angle was wide, but the consistency was not good when it was narrow. The angle examined by a gonioscope was wider than that by UBM. When the iris root insertion was evaluated in a narrow angle, the consistency was also not good, and when the peripheral iris morphology was evaluated, there were almost inconsistent results in one-fourth of the patients. CONCLUSIONS: The results of chamber angle examined by a gonioscope show a little wider than its natural status. Especially, it is difficult to distinguish the functional closure from the adhesive closure. Under the influence of light, the determination of iris root insertion by a gonioscope has a sense of conjecture. When peripheral iris morphology is evaluated, the influence of irregular iris might result in a wrong conclusion. Therefore, the technique of gonioscopic examination should be improved.

Adult↗
PubMed1998

The transmembrane domains of ectoapyrase (CD39) affect its enzymatic activity and quaternary structure.

Mammalian ectoapyrase (CD39) is an integral membrane protein with two transmembrane domains and a large extracellular region. The enzymatic activity of ectoapyrase is inhibited by most detergents used for membrane protein solubilization. In contrast, the enzymatic activities of soluble E-type ATPases, including potato tuber (Solanum tuberosum) apyrase and parasite ecto-ATPase, are not affected by detergents. Here we show that ectoapyrase is a tetramer and that detergents that reduce the activity of the enzyme promote dissociation of the tetramer to monomers. We expressed a secreted form of the ectoapyrase in COS-7 cells by fusing the signal peptide of murine CD4 with the extracellular domain of the ectoapyrase. The soluble ectoapyrase is catalytically active and its activity is not affected by detergents. Mutants of the ectoapyrase with only the NH2- or the COOH-terminal transmembrane domain are membrane-bound, and their activity is no longer affected by detergents. The enzymatic activity of all of the mutant proteins is less than that of the native enzyme. These results suggest that the proper contacts between the transmembrane domains of the monomers in the tetramer are necessary for full enzymatic activity.

Adenine Nucleotides↗
PubMed1998

Anatomic considerations of pedicle screw placement in the thoracic spine. Roy-Camille technique versus open-lamina technique.

STUDY DESIGN: In this cadaveric study, the outcomes of two techniques for pedicle screw placement in the thoracic spine were compared. OBJECTIVES: To assess the Roy-Camille technique, and to determine whether pedicle screw placement, aided by partial laminectomy, could decrease the incidence of pedicle violations. SUMMARY OF BACKGROUND DATA: Pedicle screw fixation in the thoracic spine remains technically challenging. The Roy-Camille method may be one of the leading techniques of thoracic pedicle screw placement. However, there are few studies evaluating this technique and determining methods to decrease the incidence of thoracic pedicle penetration with screw insertion. METHODS: Ten cadaveric thoracic spines from T1 to T10 were used for pedicle screw placement. Two techniques of transpedicular screw placement were used, the Roy-Camille technique (screw placed on the right side; used in 95 screw placements) and the open-lamina technique screw placement with combined partial laminectomy (screw placed on the left side; used in 94 screw placements). After screw placement, all specimens were evaluated visually to determine violation of the pedicle. RESULTS: The screw placement with the Roy-Camille technique had a higher percentage of pedicle violation (54.7%) than did that with the open-lamina technique (15.9%). No Grade III violation was seen in the screw placement with the open-lamina technique. CONCLUSIONS: The Roy-Camille technique was associated with a high incidence of pedicle violation, whereas screw placement with a partial laminectomy significantly reduced the incidence of pedicle violation. Pedicle screw fixation in the thoracic spine remains a technical challenge and should not be used routinely. Screw placement with the open-lamina technique is recommended if pedicle screw fixation is strongly indicated in the thoracic spine.

Aged↗
PubMed1998

[Clinical and experimental study of Tongqiao tablet in treating catarrhal otitis media].

OBJECTIVE: To assess the effect of Tongqiao tablet (TQT) in treating catarrhal otitis media (COM). METHODS: Ninety-six patients of COM were randomized into two groups, 52 patients in the treatment group were treated with TQT and 44 patients of the control group were treated with western medicine. Animal experiment study on effect of TQT was also carried out. RESULTS: The total effective rate and the cure and markedly improved rate of the treatment group were 92.31% and 53.85% respectively, while those in the control group were 68.18% and 27.27% respectively, the difference between the two groups was significant statistically (P < 0.01). The effect of TQT was superior to that of the western medicine. Experimental study indicated that TQT had remarkable inhibiting effect on inflammation and granuloma formation. CONCLUSION: TQT is an effective drug for treatment of COM.

Adolescent↗
PubMed1997

Screening of SLE sera using purified recombinant Sm-D1 protein from a baculovirus expression system.

The Sm-D1 polypeptide is a major target of autoantibodies diagnostic for systemic lupus erythematosus (SLE). The cDNA encoding the human antigen was expressed as a full-length, nonfusion protein using a eukaryotic baculovirus expression system. This recombinant version of Sm-D1 (rSm-D1) was purified to apparent homogeneity by a combination of differential extraction steps and FPLC chromatography. A direct antibody-binding ELISA was developed using the purified antigen. There was 96% correlation between the rSm-D1 and bona fide Sm-D1 from either HeLa cells or rabbit thymus when tested against Sm-positive patient sera by ELISA. The baculovirus-expressed Sm-D1 is reactive not only with patient anti-Sm sera, but also with anti-Sm monoclonal antibodies. Our results suggest that this rSm-D1 mimics the bona fide sources, providing a valuable addition to the roster of antigens available for SLE screening, epitope mapping and overall structure study.

Antibodies, Monoclonal↗
PubMed1997

Randomised controlled trial: comparison of colloid or crystalloid for partial exchange transfusion for treatment of neonatal polycythaemia.

AIM: To compare the efficacy of using isotonic saline (crystalloid) or 5% albumin (colloid) as replacement fluid in partial exchange transfusion (PET) for the treatment of neonatal polycythaemia. METHODS: One hundred and two polycythaemic full term infants were randomly allocated to receive PET with either isotonic saline or 5% albumin. The criteria for PET were: (a) venous haematocrit > or = 0.7; or (b) venous haematocrit 0.65-0.69 with symptoms or signs attributable to polycythaemia. RESULTS: PET with either saline (n = 53) or 5% albumin (n = 50) resulted in a significant and sustained decline in haematocrit up to 24 hours after PET. Although the immediate haemodilution effect of isotonic saline was statistically smaller than that of 5% albumin (decline in haematocrit 19.3% vs 22.8% of pre-PET value), the difference was too small to be of any clinical significance, and the haematocrit at 4 or 24 hours after PET did not differ significantly between the two groups. PET with either replacement fluid was not associated with any complication. The serum sodium and potassium concentrations were not significantly affected by the PET in either group. CONCLUSIONS: Both isotonic saline and 5% albumin are effective when used as replacement fluid in PET for the treatment of neonatal polycythaemia. Isotonic saline, which is cheaper and free of infection, should be the replacement fluid of choice.

Albumins↗
PubMed1997

[The relationship between smoking and periodontal diseases].

The oral hygiene, periodontal status and smoking habits of 432 males were surveyed in order to study the relationship between smoking and periodontal disease. The results showed that there was no difference between smokers and non-smokers on oral hygiene and gingivitis. The percentage of smokers with periodontitis was higher than that of non-smokers. The prevalence of periodontitis in heavy smokers was higher than that of light and middle smokers and non-smokers. It was indicated that smoking may be one of the risk factors in the development of periodontal disease.

Adult↗
PubMed1997

[Effect of stud attachment post design on dentin stress distribution].

The shape design of attachment post is crucial factors influencing post retention and stress distribution to the dentin. By means of CAD and FEA, the present study investigated the effects of the shape designs of attachment posts on the stress distribution in dentin. The results indicated that the taper post had wedging effects on the dentin and produced higher Von Misses stress than that of parallel side post and the Von Misses stress value of the dentin was about 1.1 times. The maximum Von Misses stress value that the design of the thread post produced was about 1.06 times the stress of the nonthread post did. However, the effects of post design on the dentin were minor compared with the bite force directions. In the same post design, the maximum Von Misses stress in dentin with 45 degree oblique force was about 2.1 times with vertical force. Therefore, reducing oblique force is the main method to prevent root fracture in clinic.

Computer-Aided Design↗
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

Artificial neural network to assist psychiatric diagnosis.

BACKGROUND: Artificial Neural Network (ANN), as a potential powerful classifier, was explored to assist psychiatric diagnosis of the Composite International Diagnostic Interview (CIDI). METHOD: Both Back-Propagation (BP) and Kohonen networks were developed to fit psychiatric diagnosis and programmed (using 60 cases) to classify neurosis, schizophrenia and normal people. The programmed networks were cross-tested using another 222 cases. All subjects were randomly selected from two mental hospitals in Beijing. RESULTS: Compared to ICD-10 diagnosis by psychiatrists, the overall kappa of BP network was 0.94 and that of Kohonen was 0.88 (both P < 0.01). In classifying patients who were difficult to diagnose, the kappa of BP was 0.69 (P < 0.01). ANN-assisted CIDI was compared with expert system assisted CIDI (kappa = 0.72-0.76); ANN was more powerful than a traditional expert system. CONCLUSION: ANN might be used to improve psychiatric diagnosis.

Adult↗
PubMed1996

[Regional brain calcium change in rabbit cerebral ischemia].

OBJECTIVE: To study whether regional brain calcium change would be an important factor for ischemic neuranal damage and whether calcium antagonist would exert protective effects on cerebral ischemia. METHODS: OCPC autoanalyzer method, was used to measure the regional brain calcium and observe the influence of flunarizine (FNZ) 48 hours after the rabbit middle cerebral artery occlusion (MCAO). RESULTS: 48 hours after MCAO, the calcium in the ischemic middle cerebral artery territory was 10.8 times as much as that in the pseudo-occluded controls, and FNZ could significantly decrease the ischemic brain calcium (P < 0.05) and the ischemic cerebral edema (P < 0.01). CONCLUSION: Caoverload was animportant factor leading to ischemic neuronal death, and FNZ has protective effects on cerebral ischemia.

Animals↗
PubMed1995

High incidence of juvenile Graves' disease in Hong Kong.

OBJECTIVE: Childhood Graves' disease has been reported to be rare and epidemiological data on its incidence are limited. In our Paediatric Endocrine Clinic, Graves' disease was the most common thyroid disorder seen. There is no previous epidemiological study on Graves' disease in Chinese children. This study was performed to determine the incidence of childhood Graves' disease in Hong Kong Chinese. DESIGN AND PATIENTS: We established a registry of childhood Graves' disease in 1990 at our centre, which has a catchment population of 1,010,000 with 240,000 under 15 years of age. Graves' disease was diagnosed on clinical features, diffuse thyroid gland enlargement, elevated free thyroxine or triiodothyronine levels with suppressed TSH level. All confirmed cases were recorded prospectively. Population data were obtained from the Statistics Department of the Hong Kong Government. RESULTS: Forty-six Chinese children under 15 years of age had a confirmed diagnosis of Graves' disease during the study period from January 1990 to December 1994. The overall incidence was 3.8/100,000/year with a 95% confidence interval of 1.8-7.3/100,000/year. Incidence was low in children under 4 years. The highest incidence was in girls between 10 and 14 years of age at 15.5/100,000/year. The cumulative incidence for boys and girls of developing Graves' disease during the first 15 years was 11 and 104 per 100,000 respectively. CONCLUSIONS: Our data demonstrate a very high incidence of Graves' disease in Hong Kong Chinese children, with an overall incidence about 5 times that reported in Danish children. A female predominance was found in all three age groups (0-4, 5-9 and 10-14 years) and was particularly striking in the adolescent girls.

Adolescent↗
PubMed1995

[Magnetic resonance imaging in the diagnosis and staging of endometrial carcinoma].

The value of magnetic resonance imaging (MRI) in the diagnosis and staging of endometrial carcinoma was studied in 43 cases of clinically suspected endometrial carcinoma and 7 normal women. All of the 43 cases showed abnormal endometria measured by MRI, among which were pathologically proven 40 cases of endometrial carcinoma, 2 cases of endometrial polyps and 1 case of adenomyosis. This suggested that MRI showed a high susceptibility in the diagnosis of endometrial carcinoma, and a lack of specificity. MRI could predict myometrial invasion, its accuracy being verified by surgico-pathological findings in 11 of 13 cases. MRI staging was correct in 10 of the 13 primarily operated cases, and only half of the clinical staging was in conformity with surgical staging. The results suggest that MRI is useful in the staging of endometrial carcinoma and therefore is of value in the choice of treatment planning, although it is not yet an ideal diagnostic aid to detect small metastatic pelvic lesions.

Adult↗
PubMed1994

Extensive anterior decompression for mixed cervical spondylosis. Resection of uncovertebral joints, neural and transverse foraminotomy, subtotal corpectomy, and fusion with strut graft.

STUDY DESIGN: This study examined a new operative procedure for treating mixed cervical spondylosis. OBJECTIVES: To relate postoperative results with extensive decompression using a surgical microscope. SUMMARY OF BACKGROUND DATA: Based on the dissection cadavers and clinical practice, extensive anterior decompression has been designed for mixed cervical spondylosis. It has not been reported that the cervical cord, nerve roots, and vertebral arteries have been decompressed thoroughly at the same time. METHODS: Fifteen patients with mixed cervical spondylosis were treated with extensive anterior decompression using an operative microscope. The pathologic segments in all patients were identified preoperatively with cervical radiography, myelography, computed tomography, computed tomographic myelography, and magnetic resonance imaging. The Japanese Orthopaedic Association classification was used to assess the follow-up results. The operative results demonstrated the efficacy of the surgical approach. RESULTS: All patients improved neurologically, with the average Japanese Orthopaedic Association score improving from 6.3 points preoperatively to 12.4 points at follow-up examination. The plain radiography, computed tomography, and magnetic resonance imaging follow-up examination showed that the anterior part of the cervical canal and the transversaria or neural foramina were enlarged, and that there was satisfactory bony fusion without signs of nonunion and other complications. CONCLUSIONS: Extensive anterior decompression (resection of uncovertebral joints, neural and transverse foraminotomy, subtotal corpectomy, and fusion with strut graft), a new surgical procedure for treating mixed cervical spondylosis, led to excellent follow-up results.

Adult↗
PubMed1994

1H NMR and spin-labeled EPR studies on the interaction of calmodulin with jujuboside A.

Jujuboside A (JuA), an effective component of sanzaoren, a Chinese herbal medicine, is a noncompetitive inhibitor of calmodulin (CaM). The interaction of JuA with CaM has been investigated with 1H NMR and spin-labeled EPR spectroscopies. The 1H NMR experiments showed that JuA has two kinds of binding sites on CaM: one locates in the N-terminus, the other locates in the C-terminal region of the polypeptide chain. The EPR studies on 3-maleimido-2,2,5,5-tetramethyl-1-pyrrolidinyloxyl labeled CaM (spin-labeled CaM) revealed that each CaM molecule can bind at least two JuA molecules. Binding of JuA affects the environments of some lysine residues (most likely Lys-74 and Lys-94), suggesting that JuA binds to CaM through hydrophobic interaction.

Amino Acid Sequence↗
PubMed1988

Plasma levels of 7B2 (a novel pituitary polypeptide) and its molecular forms in plasma and urine in patients with chronic renal failure: possible degradation by the kidney.

Plasma immunoreactive (IR)-7B2 was measured in patients with chronic renal failure (CRF), using a specific radioimmunoassay. The mean (+/- S.E.M.) concentration of plasma IR-7B2 in CRF patients under hemodialysis (502 +/- 36 pg/ml, n = 27) was significantly higher than that in normal subjects (men, 52.9 +/- 1.7 pg/ml (n = 179); women, 55.8 +/- 1.3 pg/ml (n = 198]. Significant correlations between plasma levels of IR-7B2 and those of blood urea nitrogen, creatinine and beta 2-microglobulin were evident in non-dialyzed CRF patients. In the analyses of pooled plasma and urine obtained from normal subjects on gel permeation chromatography, a major peak of IR-7B2 was observed at an apparent molecular weight of 20,000 in the plasma, and at a position of a smaller molecular weight in the urine. These results suggest that 7B2 is degraded mainly in the kidney and that measurement of plasma 7B2 may serve as an appropriate tool for assessing renal function.

Adult↗