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Biomedical subjects

Ke Zhu

Publications and source records attributed to Ke Zhu.

8 recordsLinked to original sources
PubMed2005

Expression, purification, and immobilization of His-tagged D-amino acid oxidase of Trigonopsis variabilis in Pichia pastoris.

High-level expression of D: -amino acid oxidase (DAO) has been reported in Pichia pastoris by integrating the DAO gene under the control of the alcohol oxidase promoter (PAOX1). However, the time taken to reach peak product concentration is usually long (approximately 43 h), and cultivation requires tight regulation of methanol feeding. In this paper, we describe the expression of His-tagged DAO (HDAO) in P. pastoris using the glyceraldehydes-3-phosphate dehydrogenase promoter (PGAP). The maximal level of HDAO expression using the PGAP integrant is attained in 13 h and is equal to that obtained using the PAOX1 integrant in 43 h. We also explored the possibility of secreting HDAO in P. pastoris. In-frame fusion of Saccharomyces cerevisiae alpha-factor secretion signal under a PGAP or PAOX1 resulted in low-level secretion of active HDAO, which was not of practical use. The intracellularly expressed HDAO under PGAP was purified by agar-based affinity support and then immobilized on Amberzyme oxirane resin. The immobilized HDAO, with specific activity of 75 U g-1 (wet weight), could be recycled more than 14 times without significant loss of activity. The data suggest that intracellular production of HDAO under PGAP, followed by affinity purification and immobilization on oxirane resin, may serve as an effective process for the manufacture of immobilized DAO for industrial application.

Bioreactors↗
PubMed2004

[Screening SCN4A gene for mutations with denaturing high performance liquid chromatography technology in a Chinese family with normokalemic periodic paralysis].

OBJECTIVE: To study the clinical features of normokalemic periodic paralysis (normoKPP) and to confirm the relation between Met1592Val mutation and normoKPP and clarify its clinical features. METHODS: The clinical features of 14 patients in a Chinese family of normoKPP were summarized. All 24 exons of SCN4A gene were screened with denaturing high performance liquid chromatography (DHPLC) technology, and then sequence analysis was performed on those with abnormal elution peak. RESULTS: This family showed typical clinical features of normoKPP without myotonia. The progress of most patients was benign. Two missence mutations were found in exon 1 and exon 24 respectively. Linkage analysis and direct sequencing showed the mutation in exon 1 was g189a, a benign polymorphism, and the mutation Met1592Val in exon 24 was responsible for this disease. CONCLUSION: The mutation Met1592Val does exist in Chinese patients, and lead to normoKPP. NormoKPP is similar to hyperKPP not only in clinical futures but also in genetic level.

Adult↗
PubMed2004

[The mutation V781I in SCN4A gene exists in Chinese patients with normokalemic periodic paralysis].

OBJECTIVE: In this report are reviewed two unrelated patients with typical normokalemic periodic paralysis (normoKPP) features and the results of screening the SCN4A gene for the disease-related mutation. METHODS: Two sporadic cases with normoKPP were screened for previously known mutations in SCN4A gene (T704M, A1156T, M1360V, I1495F, M1592V) that lead to hyperKPP; denaturing high performance liquid chromatography (DHPLC) was used. Then the rest exons of SCN4A gene were screened by DHPLC, and sequence analysis was performed on those with DHPLC chromatogram variation when compared with unaffected control. RESULTS: Two cases and one patient's father were detected with V781I, which was proved to be a singular missense mutation in SCN4A gene. CONCLUSION: The mutation V781I exists in Chinese patients with normoKPP and may be responsible for normoKPP.

Adult↗
PubMed2003

PET imaging of brain function while puncturing the acupoint ST36.

OBJECTIVE: To explore the experimental method of obtaining position emission tonogiaphy (PET) imaging evidence of changes in cerebral function by puncturing the Stomach 36 (ST36, Zusanli) acupoint. METHODS: Data on changes of cerebral glycometabolism were obtained from six healthy male volunteers with positron emission tomography. Visual experimental evidence, as well as statistical parametric mapping (SPM), was gathered while puncturing the ST36 (Zusanli, right leg) acupoint. RESULTS: There was increased glycometabolism in the hypothalamus, head of the caudate nucleus, temporal lobe, the sinistral cerebellum, postcentral gyrus, and brain stem while the acupoint ST36 was being punctured. CONCLUSIONS: Acupuncture on ST36 can lead to increase in glycometabolism in the vegetative nerve centers, which is correlated with gastric function. Visual experimental evidence of ST36 acupuncturing on functional gastrointestinal disorder was obtained in our study.

Acupuncture↗
PubMed2002

[Antigenicity and physicochemical properties of two human NR1a polypeptides related to activation of NMDA receptor].

OBJECTIVE: To investigate the distribution of antigenic sites in two human NR1a polypeptides related to activation of N-methyl-D-aspartate receptor (NMDAR) and their physicochemical properties. METHODS: The amino acid sequences of two polypeptides, P1, a region containing 151 amino acid residues preceding the first transmembrane domain of the human NR1a, and P2 with 144 residues following the third transmembrane domain, were obtained from protein database by GOLDKEY software (4.0 version). Four parameters including Hopp-Woods and Kyte hydrophilicity, Janin accessibility, Karplus-Schulz flexibility, and Welling antigenicity were used to determine the antigenic sites, and Prosite programme and Chou-Fasman method were employed to analyze their related sequence motifs and the secondary structures. Finally, comparison of the comprehensive predictions with some of the available experimental information was made. RESULTS: There were about six and seven antigenic sites containing 8 approximately 15 residues in the P1 and P2 polypeptides respectively. The antigenic sites in P1 were mainly located in the amino terminal, but the ones in P2 were dispersed rather uniformly. Many sites in P2 polypeptide including some residues in its initial part, the amino terminal, showed higher hydrophilicity, accessibility, and antigenicity than those in P1. In addition, P1 and P1 were also different in the primary and secondary structure. P1 contained more cysteine residues and was rich in random coils, while P2 contained more aromatic residues and exhibited mainly helical structures. CONCLUSION: Both human NR1a polypeptides related to activation of NMDA receptor, P1 and P2, have a certain amount of antigenic sites. Compared with P1, P2 may be of higher antigenicity, and may be more easily used as a molecular target in immunization intervention to control the activation of NMDAR.

Amino Acid Motifs↗
PubMed2002

Deep cerebral venous thrombosis in adults.

OBJECTIVE: To investigate the pathogenesis, clinical features, radiographic findings and therapeutic outcomes of non-acute intracranial deep venous thrombosis in adults. METHODS: Five patients who presented with increased intracranial pressure were examined with computed tomography, magnetic resonance and angiography, diagnosed as having non-acute intracranial deep venous thrombosis, and treated with thrombolytic therapy. They were reviewed retrospectively. RESULTS: There were 3 men and 2 women, aged from 22 to 49 years. Symptom duration ranged from 1 month to 7 months, and 4 of the 5 patients were associated with venous sinus thrombosis. Two patients developed cold and fever before the onset of disease, and 3 patients had no evident predisposing factors. After the infusion of thrombolytic and systemic anti-coagulant therapy, the neurological symptoms and signs of the patients were alleviated. CONCLUSIONS: Digital subtraction angiography (DSA) is more sensitive and accurate than MRI on diagnosing intracranial deep venous thrombosis. It may play an important role in the assessment of the treatment of intracranial deep venous thrombosis. Thrombolysis and anticoagulation of intracranial deep venous thrombosis appears to be a safe and efficacious treatment not only in the acute stage but also in the non-acute stage.

Adult↗
PubMed2002

Detection of an unkown peak at 1.2 ppm in proton magnetic resonance spectra of cats with cerebral ischemic necrosis.

OBJECTIVE: To confirm an unknown peak (Pu) in proton magnetic resonance spectra ((1)H-MRS) in cats with permanent focal cerebral ischemia, and surmise its potential value of application. METHODS: After focal cerebral ischemia, diffusion-weighted imaging (DWI) was used to identify regions of ischemia for (1)H-MRS voxel localization with the assistance of stereotaxic atlas of cat brain. (1)H-MRS was used to monitor the progression of focal cerebral ischemia in 6 cats over a period of 7 d following middle cerebral artery occlusion (MCAO). The changes in lactate, N-acetyl-aspartate (NAA), choline, creatine, and Pu were observed. RESULTS: In the involved regions, lactate was elevated almost immediately after the onset of cerebral ischemia, and NAA declined within several hours of acute infarction. The Pu at 1.2 ppm was persistently detected in the affected cerebral areas 2 to 7 d after MCAO. CONCLUSION: Pu has a close relationship with cerebral ischemia necrosis and may be a intrinsic production of the necrotic tissue, which can be utilized as a specific marker and therefore has important clinical diagnostic value.

Animals↗