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Biomedical subjects

X Bao

Publications and source records attributed to X Bao.

At least 73 records · Page 4Linked to original sources
PubMed1997

Effect on product formation in recombinant Saccharomyces cerevisiae strains expressing different levels of xylose metabolic genes.

The XYL1 and XYL2 genes from Pichia stipitis encoding xylose reductase (XR) and xylilitol dehydrogenase (XDH), respectively, were transformed into Saccharomyces cerevisiae. These two genes were placed in different directions under the control of the alcohol dehydrogenase I (ADHI) and phosphoglycerate kinase (PGK) promoters and inserted into the E. coli-yeast shuttle plasmid YEp24. Different recombinant S. cerevisiae strains were constructed with different specific activities of XR and XDH. The highest XR or XDH activities were obtained when the expressed gene was controlled by the PGK promoter and located downstream after the ADHI promoter-gene-terminator sequence. The XR/XDH ratio (ratio of specific enzyme activities of XR and XDH) in these recombinant S. cerevisiae strains varied from 17.5 to 0.06. In order to enhance xylose utilization, in the XYL1, XYL2 containing S. cerevisiae strains, the native TKL1 gene encoding transketolase and the TALI gene encoding transaldolase were also overexpressed, which showed considerably good growth on the xylose plate. Fermentation of the recombinant S. cerevisiae strains containing XYL1, XYL2, TKL1, and TAL1 were studied with mixtures of glucose and xylose. The strain with XR/XDH ratio of 0.06 consumed 3.25 g/L xylose and formed no xylitol and less glycerol and acetic acid, but more ethanol compared with the strains with a higher XR/XDH ratio.

Aldehyde Reductase↗
PubMed1997

Early intervention improves intellectual development in asphyxiated newborn infants. Intervention of Asphyxiated Newborn Infants Cooperative Research Group.

OBJECTIVE: To evaluate the effect of early intervention on the intellectual development in asphyxiated newborn infants. METHODS: Full term asphyxiated infants (Apgar score < or = 6 at 5 minutes after birth) were randomly assigned to early intervention group (34 cases) and conventional care (30 cases) group. The normal control group consisted of 38 infants. Sex, mother's educational background, environmental condition and physical development were not significantly different in the 3 groups. Zero to two years early intervention program was compiled on basis of the national and foreign material about 1 month ahead of average development of the child. It included motor, cognitive, speech development and social behavior. Parents were instructed to carry out early intervention. RESULTS: At the age of 1.5 years, average score of mental development index (MDI) in early intervention group was 14.6 higher than that in conventional care group (F = 18.86, P < 0.0001). MDI score in early intervention group caught up with that in normal control group (F = 2.17, P > 0.05). Conventional care group was 9.7 lower than normal control group (F = 10.14, P < 0.01). Two of 30 cases (6.7%) in conventional care group was mentally retarded while none was mentally retarded in the early intervention group. CONCLUSIONS: The results showed that the early intervention could promote intellectual development of asphyxiated infants and be of much benefit to the prevention of mental retardation.

Asphyxia Neonatorum↗
PubMed1996

Ethanolic fermentation of xylose with Saccharomyces cerevisiae harboring the Thermus thermophilus xylA gene, which expresses an active xylose (glucose) isomerase.

The Thermus thermophilus xylA gene encoding xylose (glucose) isomerase was cloned and expressed in Saccharomyces cerevisiae under the control of the yeast PGK1 promoter. The recombinant xylose isomerase showed the highest activity at 85 degrees C with a specific activity of 1.0 U mg-1. A new functional metabolic pathway in S. cerevisiae with ethanol formation during oxygen-limited xylose fermentation was demonstrated. Xylitol and acetic acid were also formed during the fermentation.

Aldose-Ketose Isomerases↗
PubMed1996

[Mutation analysis of mitochondrial DNA of children with Rett syndrome].

OBJECTIVE: To identify whether mitochondrial DNA (mtDNA) mutation is involved in the pathogenesis of Rett syndrome (RS), we undertook a mutation analysis of the mtDNA genome. METHODS: mtDNA from 15 children with RS and 14 their mothers were analysed by using Southern hybridization, polymerase chain reaction (PCR), single strand conformation polymorphism (SSCP) and DNA direct sequencing. Total DNA was isolated from white blood cells. RESULTS: Southern hybridization with whole mtDNA probe revealed no large deletions in mtDNA. PCR amplification and SSCP analysis showed mutation(s) in the region 2650-3000 encoding 16SrRNA of mtDNA in 13 RS patients and 11 their mothers. DNA sequence analysis and mismatch PCR showed a point mutation (C-->T) at the position 2835 in 7 RS patients and 6 their mothers. The same mutation was not found in 30 normal controls. CONCLUSION: These data indicate that mtDNA may play a role in Rett syndrome.

Adult↗
PubMed1996

[Intramedullary spinal teratoma].

We treated 5 cases of intradullary spinal teratomas from 1974 to 1995, accounting 0.636% of all intraspinal tumors and 45.45% of all teratomas of spinal cord admitted in the same time. The origin of this tumor is controversial. It is not easy to differentiate this tumors from other intramedullary spinal tumors on clinical grounds. CT and MR scans of this tumor enabled us to make the preoperative diagnosis of teratoma. Resection is the only treatment of choice.

Adolescent↗
PubMed1995

Transsynaptic localization of pharyngeal premotor neurons in rat.

We determined the anatomy and connectivity of the brainstem circuit controlling the buccopharyngeal phase of swallowing, using pseudorabies virus to identify linked circuits of neurons. Pharyngeal vagal afferents terminate on premotor neurons in the interstitial and intermediate subnuclei of the nucleus of the solitary tract, which in turn, innervate pharyngeal motoneurons in the semicompact subnucleus of the nucleus ambiguus. This circuit is separate and distinct from the esophageal swallowing circuit.

Animals↗
PubMed1995

Co-localization of NOS and NMDA receptor in esophageal premotor neurons of the rat.

Nitric oxide (NO) production following NMDA receptor stimulation plays a role in signaling between neurons. Using trans-synaptic tracing with pseudorabies virus (PRV), immunocytochemistry and histochemistry, we have demonstrated the expression of NMDAR1 and nitric oxide synthase (NOS) within brain stem neurons controlling esophageal peristalsis. PRV-immunoreactive second order esophageal premotor neurons of the central subnucleus of the nucleus of the solitary (NTScen) expressed NMDAR1 and NOS. First order motoneurons of the compact formation of the nucleus ambiguus (NAc) expressed NMDAR1, but did not contain NOS. NTScen neurons may synthesize and release NO in response to NMDA activation, suggesting a role for NO in the coordination of esophageal motility.

Animals↗
PubMed1995

Localization of nitric oxide synthase in the brain stem neural circuit controlling esophageal peristalsis in rats.

BACKGROUND/AIMS: The central subnucleus of the nucleus of the solitary tract has been implicated in central reflex control of esophageal peristalsis. This study determined the presence of nitric oxide synthase in the brain stem circuit controlling esophageal peristalsis by combining transsynaptic retrograde tract tracing with pseudorabies virus and nicotinamide adenine dinucleotide phosphate diaphorase (NADPH) histochemistry. METHODS: Virus was injected into the esophagus of 10 of 15 rats. After 60-63 hours, brain sections were processed for viral immunofluorescence and NADPH histochemistry. RESULTS: Fluorescent neuronal labeling was limited to the compact formation of the nucleus ambiguus and the central subnucleus of the nucleus of the solitary tract. Most fluorescence-labeled neurons in the central subnucleus stained positively for NADPH (double labeled). In the compact formation, there were almost no double-labeled neurons; however, NADPH-stained terminals surrounded fluorescence-labeled motoneurons. CONCLUSIONS: NO synthase is present in premotor neurons of the central subnucleus of the nucleus of the solitary tract that innervate esophageal motoneurons in the compact formation of the nucleus ambiguus. NADPH staining in both somata and terminals of esophageal premotor neurons suggests that NO is involved in neurotransmission in the central subnucleus and at the site of synaptic contact between esophageal premotor neurons and motoneurons in the compact formation of the nucleus ambiguus.

Amino Acid Oxidoreductases↗
PubMed1995

The relationship of Piry virus to other vesiculoviruses: a re-evaluation based on the glycoprotein gene sequence.

By sequencing the 3 half of the Piry virus genome, we show that Piry virus, like the other vesiculoviruses, contains the genes for nucleoprotein N, phosphoprotein P, matrix protein M, glycoprotein G and polymerase protein L, in that order. Our analysis of the Piry G protein sequence suggests that Piry and Chandipura are related to each other as closely as the Indiana and New Jersey vesicular stomatitis virus serotypes are to each other. A re-examination of amino acid sequences in the nucleocapsid protein shows that this relationship is also true of the more conserved central region of this protein and that the greatest divergence between Piry and Chandipura has occurred in two other regions of the nucleocapsid protein.

Amino Acid Sequence↗
PubMed1995

[Identification on the botanical origin of xueshangyizhihao produced in Shaanxi, Gansu, Sichuan Provinces and Ningxia Hui Autonomous Region].

The botanical origin of Xueshangyizhihao should be Aconitum brachypodum var. laxiflorum produced in Dongchuan, Huize and Xundian districts in Yunnan Province. Recently, this herb has been found coming from Shaanxi, Gansu, Sichuan Provinces and Ningxia Hui Autonomous Region. Botanical identification show that except the one from Sichuan being of the same origin as that from Yunnan, this herb consists essentially of the species of genus Aconitum, mainly A. flavum, A. pendulum, and others such as A. sungpanense, A. polyschistum and A. iudlowii.

China↗
PubMed1995

A new and cheap medical examination system with artificial intelligence.

This is a medical examination system with artificial intelligence. It is used to find persons who want to obtain higher professional posts in the medical field, including doctors, dentists, nurses, pharmaceutists, etc. It has a question bank of 536,000 multiple choice questions (MCQs), of which 59,500 have pictures. Ten percent of the MCQs is updated every year; the old MCQs in the question bank are used as exercises for the persons who want to obtain higher professional posts. The system, with three distinctive degrees of difficulty, is applicable to three different professional posts: the assistant physician, the resident, and the attending physician. It ensures the general level of assessment for the same professional post, regardless of when one wants to take the system. In addition, the system also guarantees the consistency of the following three factors: the constituent of sub-professions, the classification of MCQs, and the degree of difficulty of each MCQ. Another feature of the system is that the passing score need not be the traditional standard passing score of 60. The passing score is determined by the system according to the requirements of the different professional posts and the degree of difficulty of the MCQs in the system. Therefore, the new method for passing the system is more rational than the traditional one. Moreover, the final score given by the system will be standardized to eliminate sampling errors. The reliability of the system will also be tested after each examination. If the coefficient of reliability is lower than 0.85, the scores will be canceled and examination will be repeated. The system can accept 96 persons simultaneously taking the examination with on-line computers. The people who work in remote places can take examination in their hospital with a personal computer linked via telephone. The system has already been approved by the relevant authoritative departments in China. It has been running successfully for more than six years. During this period of time, 125,645 candidates have taken the exam; 64,078 have passed the examination and have been promoted to higher professional posts. The system runs on local area network and uses a program written in PROLOG and FoxPro. It is estimated that the total cost of developing the system is less than $46,000 (US).

Artificial Intelligence↗
PubMed1994

Cystic fibrosis transmembrane conductance regulator protein expression in brain.

The cystic fibrosis transmembrane conductance regulator protein (CFTR) has been identified in bovine brain clathrin-coated vesicles, rat brain and a human neuroblastoma cell line using affinity-purified polyclonal peptide antibodies against CFTR. Immunocytochemical staining of multiple dendrites and soma of neurons of the diencephalon, midbrain, pons and medulla oblongata, has also been demonstrated. Whole cell lysates and membranes derived from rat brain, neuroblastoma cells and bovine brain clathrin-coated vesicles express the mature 150-165 kDa and 130 kDa unglycosylated forms of CFTR. The localization of CFTR to brain regions controlling homeostasis and energy expenditure may relate to the pathogenesis of non-pulmonary manifestations of cystic fibrosis. CFTR expression in neurons and coated vesicles suggests a possible effect on neuropeptide vesicle trafficking by mutant CFTR.

Amino Acid Sequence↗
PubMed1994

Dendritic architecture of hypoglossal motoneurons projecting to extrinsic tongue musculature in the rat.

The tracer, cholera toxin-horseradish peroxidase, was used to determine the dendritic architecture and organization of hypoglossal motoneurons in the rat. In 22 animals, the tracer was injected unilaterally into either the geniohyoid, genioglossus, hyoglossus, or styloglossus muscle. Within the hypoglossal nucleus, motoneurons innervating the extrinsic tongue muscles were functionally organized. Geniohyoid and genioglossus motoneurons were located within the ventrolateral and ventromedial subnuclei, respectively, while hyoglossus and styloglossus motoneurons were located within the dorsal subnucleus. Motoneurons located in all subnuclear divisions were found to have extensive dendrites that extended laterally into the adjacent reticular formation and medially to the ependyma. Less extensive extranuclear dendritic projections were found in the dorsal vagal complex and median raphe. Prominent rostrocaudal and mediolateral dendritic bundling was evident within the ventral subnuclei and dorsal subnucleus, respectively. Dendritic projections were also found extending inter- and intrasubnuclearly with a distinct pattern for each muscle. These data suggest that the varied and extensive dendritic arborizations of hypoglossal motoneurons provide the potential for a wide range of afferent contacts for, and interactions among, motoneurons that could contribute to the modulation of their activity. Specifically, the prominent dendritic bundling may provide an anatomic substrate whereby motoneurons innervating a specific muscle receive and integrate similar afferent input and are thus modulated as a functional unit. In contrast, the extensive intermingling of both inter- and intrasubnuclear dendrites within the hypoglossal nucleus may provide a mechanism for the coordination of different muscles, acting synergistically or antagonistically to produce a tongue movement.

Animals↗