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Biomedical subjects

X Y Dai

Publications and source records attributed to X Y Dai.

At least 19 recordsLinked to original sources
PubMed2006

Efficacy assessment of phenobarbital in epilepsy: a large community-based intervention trial in rural China.

BACKGROUND: Many people with epilepsy need not experience further seizures if the diagnosis and treatment are correct. Most epilepsy patients have convulsions, which are usually fairly easy to diagnose. This study tested a model for treatment of people with convulsive forms of epilepsy at primary health-care level in rural areas of China. METHODS: Patients with convulsive epilepsy were identified at primary care level and provided with phenobarbital monotherapy. Local physicians, who were provided with special training, carried out screening, treatment, and follow-up. A local neurologist confirmed the diagnoses. Efficacy was assessed from the percentage reduction in seizure frequency from baseline and the retention of patients on treatment. FINDINGS: The study enrolled 2455 patients. In 68% of patients who completed 12 months' treatment, seizure frequency was decreased by at least 50%, and a third of patients were seizure free. 72% of patients who completed 24 months' treatment had reduction of seizure frequency of at least 50% and a quarter of patients remained seizure free. Probability of retention was 0.84 at 1 year, and 0.76 at 2 years. Medication was well tolerated and reported adverse events were mild; only 32 patients (1%) discontinued medication because of side-effects. INTERPRETATION: This pragmatic study confirmed that this simple protocol was suitable for the treatment of convulsive forms of epilepsy in rural areas of China. Physicians with basic training could treat epilepsy patients with phenobarbital, with beneficial effects for most patients with convulsive seizures. Few cognitive or behavioural adverse events were noted, but formal psychometric testing was not done.

Adolescent↗
PubMed2003

The prevalence and treatment gap in epilepsy in China: an ILAE/IBE/WHO study.

The authors carried out a door-to-door survey to determine the prevalence of epilepsy among 55,000 people in China. The lifetime prevalence was 7.0/1000, and 41% of all persons had never received appropriate treatment. The prevalence of active epilepsy was 4.6/1000, and 63% of people with active epilepsy had not received antiepileptic treatment in the week before the survey. Figures for the prevalence and the treatment gap were significantly higher than previous estimates.

Anticonvulsants↗
PubMed2001

Longitudinal study of blood pressure and stroke in over 37,000 People in China.

As part of a longitudinal study performed in urban China, 37,655 subjects were evaluated for stroke risk factors, including having their blood pressure measured in a standard fashion. The cohort was followed for 3.5 years during which time 427 subjects experienced incident strokes--221 ischemic, 203 hemorrhagic, and 3 undefined. Both systolic and diastolic blood pressure were significantly related to risk of stroke and stroke type. Associations were stronger for systolic than diastolic blood pressure. These results emphasize the importance of systolic blood pressure, as opposed to diastolic, as a risk factor for stroke. In this study, the risk of stroke is increased by about 25% with each 10 mm Hg increase in systolic blood pressure.

Adult↗
PubMed2001

[Cloning and expression of TPS1 gene in Escherichia coli].

A S. cerevisiae TPS1 gene for trehalose-6-phosphate synthase was cloned by PCR amplification. The 1.5 kb DNA fragment was ligated to pUC19 and transformed into otsA deficient and deleted of E. coli strains FF4169 and FF4050 separately. otsA gene is encoding trehalose-6-phasphate synthase in E. coli. Restriction endonucleases digestion analysis of transformants' plasmid DNA showed that there was a cloned 1.5 kb fragment carried on the vector. The growth curve experiment result showed that the both transformants could grow well as wild type. Trehalose was synthesized and accumulated in these transformants during high osmotic stress by HPLC combined with ELSD (Evaporate light scatter detector) determination. From the result above, we could conclude that the TPS1 gene of S. cerevisiae was able to restore otsA gene function in E. coli for both osmotolerance and trehalose accumulation during salt stress.

Cloning, Molecular↗
PubMed2000

[Cloning and expression of trehalose synthase genes in Escherchia coli].

Escherichia coli trehalose synthase otsBA genes have been cloned by using transposon Mu in vivo. The cloning frequency was 1.45 x 10(-3)/Kanr transductant. Genetic complements, endonuclase digestion and partial nucleotide sequencing analysis of these clones indicated that otsBA gene was on plasmid Mud5005. Subcloning 2.87 kb DNA fragment onto expression plasmids with higher or lower copy number and transforming into E. coli recipient strain FF4050, which have otsBA genes deleted respectively, the transformed strains obtained ability of growth on medium containing 0.5 mol/L NaCl and increased trehalose synthesis under high osmotic pressure. Production and accumulation of trehalose may play an important role in crop breeding. These studies will lay an important foundation for constructing an expression vector with the otsBA genes and transformation to tobacco mediated by Agrobacterium, and obtaining ability for drought resistance and high osmotic pressure tolerance.

Cloning, Molecular↗
PubMed2000

[Isolation and characterization of PAOX2 mutant in Pichia pastoris].

Spontaneous Mut+ mutants of P. pastoris AOX1-defective expression strain have been isolated, they were identified as phenotypically utilized methanol to grow as wild type. The results obtained from measuring growth curve when cultivated in medium in which methanol as a sole carbon source and detecting HSA protein on SDS-PAGE confirmed that the mutants have increased ability to utilize methanol and express foreign HSA gene product. The promoter region of AOX2 gene from the mutants has been cloned by PCR amplification, and the DNA fragment is 1022bp in size. Sequencing analysis showed that there are two point mutations at positions of -529 and -255 from the translation initiation codon respectively. The mutations improved AOX-1 defective function and facilitate the foreign gene for higher expression.

Alcohol Oxidoreductases↗
PubMed1999

Relative contribution of LFA-1 and Mac-1 to neutrophil adhesion and migration.

To differentiate the unique and overlapping functions of LFA-1 and Mac-1, LFA-1-deficient mice were developed by targeted homologous recombination in embryonic stem cells, and neutrophil function was compared in vitro and in vivo with Mac-1-deficient, CD18-deficient, and wild-type mice. LFA-1-deficient mice exhibit leukocytosis but do not develop spontaneous infections, in contrast to CD18-deficient mice. After zymosan-activated serum stimulation, LFA-1-deficient neutrophils demonstrated activation, evidenced by up-regulation of surface Mac-1, but did not show increased adhesion to purified ICAM-1 or endothelial cells, similar to CD18-deficient neutrophils. Adhesion of Mac-1-deficient neutrophils significantly increased with stimulation, although adhesion was lower than for wild-type neutrophils. Evaluation of the strength of adhesion through LFA-1, Mac-1, and CD18 indicated a marked reduction in firm attachment, with increasing shear stress in LFA-1-deficient neutrophils, similar to CD18-deficient neutrophils, and only a modest reduction in Mac-1-deficient neutrophils. Leukocyte influx in a subcutaneous air pouch in response to TNF-alpha was reduced by 67% and 59% in LFA-1- and CD18-deficient mice but increased by 198% in Mac-1-deficient mice. Genetic deficiencies demonstrate that both LFA-1 and Mac-1 contribute to adhesion of neutrophils to endothelial cells and ICAM-1, but adhesion through LFA-1 overshadows the contribution from Mac-1. Neutrophil extravasation in response to TNF-alpha in LFA-1-deficient mice dramatically decreased, whereas neutrophil extravasation in Mac-1-deficient mice markedly increased.

Animals↗
PubMed1998

Investigation of dopamine system genes in obsessive-compulsive disorder.

Evidence from anatomical, pharmacological, and animal studies on the involvement of the dopamine system in obsessive-compulsive disorder (OCD) is mounting. This, along with evidence for a genetic diathesis provided by family and twin studies, prompted us to conduct genetic association studies of dopamine system genes in OCD. We genotyped OCD patients (n > 100) and matched controls for four loci: (1) a 40-base-pair repeat in the dopamine transporter gene; (2) the TaqIA polymorphism and the serine/cysteine variation in the D2 dopamine receptor gene; (3) an MscI polymorphism in the D3 dopamine receptor gene; and (4) a 48-base-pair repeat in the D4 dopamine receptor gene. Significant differences in allele frequencies were found between patients and controls for the D4 receptor gene, although replication is required with family-based controls before any conclusions can be entertained. This study represents the first comprehensive assessment of the roles of dopamine system genes in OCD.

Age of Onset↗
PubMed1996

No association between c-fos gene polymorphisms and sporadic Alzheimer's disease.

Although ApoE epsilon 4 is a major risk factor for sporadic Alzheimer's disease (AD), 20-30% of sporadic AD patients do not have this allele. This indicates that other risk factors are involved in the pathogenesis of sporadic AD. Studies of the genetic association between AD and polymorphisms in the c-fos gene, a candidate gene for AD, were conducted. The polymorphisms of DsaI in exon 2 and Sau3 AI in intron 2 were examined in 89 patients diagnosed as sporadic cases of probable AD clinically and radiologically according to the NINCDS-ADRDA criteria. This was also undertaken in 96 controls. There was no significant difference between the groups in allele frequencies or genotype counts. Although c-fos gene as a locus conferring susceptibility to sporadic AD cannot be ruled out, these data could not support the hypothesis that a c-fos allele should be another risk factor for sporadic AD.

Aged↗
PubMed1995

The social course of epilepsy: chronic illness as social experience in interior China.

Findings are reported from a collaborative research project on the experience of epilepsy and treatment among patients and family members in Shanxi and Ningxia Provinces in China. Family, marriage, financial and moral consequences of the social experience of epilepsy support the conceptualization of chronic illness as possessing a social course. Beyond traditional concern with stigma, application of concepts of delegitimation, sociosomatic processes, coping as resistance, contestation in the evaluation of efficacy and compliance, and the cultural ontology of suffering illustrate other ways that social theory is useful in research on chronic illness and disability.

Adaptation, Psychological↗
PubMed1995

Screening for mutations at codon 717 of the amyloid precursor protein gene in Alzheimer's disease.

Three kinds of missense mutation at codon 717 of amyloid precursor protein (APP) gene (Val --> Ile; Val --> Gly; Val --> Phe) were screened in 114 patients with familial and sporadic Alzheimer's disease (AD), using a rapid testing method for each Val --> Gly and Val --> Phe mutation and Goate's method for Val --> Ile mutation based on the polymerase chain reaction. Mutations were not found in the subjects, confirming earlier suggestions that these three mutations at codon 717 of APP gene account for only a small proportion of cases of not only familial AD but also sporadic AD.

Aged↗
PubMed1994

No allelic association between Parkinson's disease and dopamine D2, D3, and D4 receptor gene polymorphisms.

Parkinson's disease is thought to be caused by a combination of unknown environmental, genetic, and degenerative factors. Evidence from necropsy brain samples and pharmacokinetics suggests involvement of dopamine receptors in the pathogenesis or pathophysiology of Parkinson's disease. Genetic association studies between Parkinson's disease and dopamine D2, D3 and D4 receptor gene polymorphisms were conducted. The polymorphism was examined in 71 patients with Parkinson's disease and 90 controls. There were no significant differences between two groups in allele frequencies at the D2, D3, and D4 dopamine receptor loci. Our findings do not support the hypothesis that susceptibility to Parkinson's disease is associated with the dopamine receptor polymorphisms examined.

Adult↗
PubMed1994

No evidence of linkage or allelic association of schizophrenia with DNA markers at pericentric region of chromosome 9.

Based on our previous study suggesting the pericentric region of chromosome 9 as of potential importance in schizophrenia, we have carried out a linkage study between the schizophrenia phenotype and the dinucleotide repeat polymorphisms D9S55, D9S15, and D9S202 in three pedigrees multiply affected with schizophrenia. In addition, we have conducted allelic association studies using 60 patients with schizophrenia and 60 controls with polymorphisms at D9S55 and D9S15 markers. No evidence for linkage or association was found. The results indicate that susceptibility genes for schizophrenia are less likely to be located at the pericentric region of chromosome 9, assuming genetic homogeneity of the pedigrees.

Alleles↗
PubMed1994

Murine VCAM-1. Molecular cloning, mapping, and analysis of a truncated form.

Vascular cell adhesion molecule-1 (VCAM-1) is a member of the Ig superfamily that shows increased expression in a number of pathologic conditions. The role of VCAM-1 in human disease remains undefined and murine models are being extensively studied to help define the importance of VCAM-1 in inflammatory disorders. We have cloned and characterized the murine Vcam1 gene including 3 kb of 5'-flanking sequences and mapped the gene to chromosome 3 near Amy1. cDNA clones isolated from a stimulated hepatic library were found to encode a truncated form of VCAM-1 (T-VCAM-1) which contains Ig domains 1 through 3 and has a unique alternative carboxyl terminus. This form arises by alternative splicing. High level expression of T-VCAM-1 in transfected L cells was sufficient to support adhesion of lymphocytes, and this adhesion was blocked by Abs to VCAM-1. Treatment of transfected COS cells with phospholipase C led to reduced levels of T-VCAM-1 on the cell surface consistent with glycosylphosphatidylinositol linkage. Northern blot analysis showed that mRNA for T-VCAM-1 is inducible in multiple tissues after stimulation with endotoxin. Both forms of VCAM-1 were expressed in cultured endothelial, fibroblast, and aortic smooth muscle cells, whereas neither form was observed in monocyte- and lymphocyte-derived lines. Differential regulation of both forms of VCAM-1 was observed in the three different cell types that are present in the vessel wall. Thus, expression of VCAM-1 is restricted and controlled at the level of transcription and by alternative splicing.

3T3 Cells↗
PubMed1994

Further evidence of no linkage between schizophrenia and the dopamine D3 receptor gene locus.

The dopamine hypothesis of schizophrenia proposed that dopaminergic pathways are involved in the etiology of the disease. In particular, interest among psychiatrists has focused on the D2 receptor because of its affinity to antipsychotic drugs. Recently a new dopamine receptor gene has been cloned, and named the dopamine D3 receptor. The D3 receptor is a potential site for antipsychotic drug action and may be involved in the pathophysiology of schizophrenia. We have carried out a linkage study between the susceptibility gene for schizophrenia and polymorphism of the dopamine D3 receptor gene in two Japanese pedigrees. The LOD scores were negative for all genetic models and for all affective status at a recombination fraction theta = 0. Linkage of DRD3 has been excluded for the model 1 (dominant model) and the model 3 (recessive model). The LOD score was -3.43 at theta = 0 for model 1 (dominant model) and broad definition of affected status. These results were consistent with previous studies.

DNA↗
PubMed1994

Mismatch PCR RFLP detection of DRD2 Ser311Cys polymorphism and schizophrenia.

We tested 100 schizophrenics and 100 controls to find association at the Serine311 Cysteine polymorphism of dopamine D2 receptor in Japanese population. There were no significant differences between the two groups. One homozygote for Cys311 was confirmed in the controls by mismatch-polymerase chain reaction and restriction fragment length of polymorphism (PCR-RFLP) analysis. None with Cys was detected among 61 individuals of nine multiply affected families with schizophrenia. Our data thus provide strong evidence against an etiological association between schizophrenia and the Ser311Cys variant. The polymerase chain reaction amplification of specific alleles (PASA) analysis was compared with the mismatch PCR-RFLP typing, revealing that the latter is more reliable than the former.

Alleles↗