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Biomedical subjects

Y Ai

Publications and source records attributed to Y Ai.

At least 19 recordsLinked to original sources
PubMed2006

Evidence for a distinct group of nestin-immunoreactive neurons within the basal forebrain of adult rats.

Nestin is an intermediate filament protein serving as a marker for neuroprogenitor and stem cells. Here we report that a cluster of previously unrecognized nestin immunoreactive (nestin-ir) neurons was located in the medial septum-diagonal band of Broca (MS-DBB) of the basal forebrain in adult rats. Nestin-ir neurons were exclusively located in the MS-DBB and intermingled with choline acetyltransferase-ir (ChAT-ir), parvalbumin-ir (PV-ir), or nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase reactive (NADPHd-reactive) neurons. However, there was no colocalization between nestin-ir and PV-ir in single neurons in MS-DBB; only about 35% of nestin-ir neurons were ChAT-ir, and 8%-12% of nestin-ir neurons were NADPHd-reactive. Morphologically, nestin-ir neurons showed a larger size of somata than that of ChAT-ir or PV-ir neurons and the distribution of nestin-ir neurons spread across the rostro-caudal extent of the MS-DBB. Moreover, retrograde tracing revealed that a significant portion of these nestin-ir neurons projected to the thalamus and hippocampus. These results, for the first time, provide strong evidence that there exists a cluster of previously unrecognized nestin-ir neurons in MS-DBB of the basal forebrain in adult rats and that these nestin-ir neurons are distinguishable from ChAT-ir, PV-ir, and NADPHd-reactive neurons.

Acetylcholine↗
PubMed2001

Abnormal migration phenotype of mitogen-activated protein kinase-activated protein kinase 2-/- neutrophils in Zigmond chambers containing formyl-methionyl-leucyl-phenylalanine gradients.

Time-lapsed video microscopy and confocal imaging were used to study the migration of wild-type (WT) and mitogen-activated protein kinase-activated protein kinase 2 (MK2-/-) mouse neutrophils in Zigmond chambers containing fMLP gradients. Confocal images of polarized WT neutrophils showed an intracellular gradient of phospho-MK2 from the anterior to the posterior region of the neutrophils. Compared with WT neutrophils, MK2-/- neutrophils showed a partial loss of directionality but higher migration speed. Immunoblotting experiments showed a lower protein level of p38 mitogen-activated protein kinase and a loss of fMLP-induced extracellular signal-related kinase phosphorylation in MK2-/- neutrophils. These results suggest that MK2 plays an important role in the regulation of neutrophil migration and may also affect other signaling molecules.

Actins↗
PubMed2001

Leukocyte-specific gene 1 protein (LSP1) is involved in chemokine KC-activated cytoskeletal reorganization in murine neutrophils in vitro.

Leukocyte-specific gene 1 protein (LSP1) is a cytoskeletal-associated protein of leukocytes that in vitro cross-links F-actin into extensively branched bundles of mixed polarity. In this study, we examined chemotaxis and superoxide production in neutrophils prepared from wild-type (WT) and Lsp1 knockout mice. Compared to WT neutrophils, Lsp1-/- neutrophils showed impairment in both migration speed and chemotaxis direction during chemokine KC-directed chemotaxis. When examined by confocal microscopy, chemotaxing Lsp1-/- neutrophils showed abnormal morphologies. They had discontinuous primary actin-rich cortexes and large membrane protrusions. When stimulated by phorbol 12-myristate 13-acetate (PMA), Lsp1-/- peritoneal neutrophils produce more superoxide than WT. The data presented suggest that LSP1 plays important roles in the regulation of neutrophil morphology, motility, and superoxide production.

Actins↗
PubMed2001

[Investigation on skin retrograde degeneration after tissue expansion].

OBJECTIVE: To study the effects of tissue expansion on tissue damage and retrograde degeneration. METHODS: 9 cases of conventional intermittent tissue expansion (CITE) and 9 cases of continuous pressure-controlled tissue expansion (CPTE) were chosen for the study. In creating of the expanded flaps, tissue samples were taken for histopathology, molecular biology and transmission electron microscope (TEM) examinations. RESULTS: Capillary bleeding, elastic and reticular fiber proliferation, arteriole thrombosis, fibroblast apoptosis and collagenolysis were observed after expansion. Retrograde degeneration was obvious in CITE group and acute lesion was obvious in CPTE group. CONCLUSION: Expansion stimulation induces tissue damage and retrograde degeneration, which indicates that the time for conventional intermittent expansion should be shortened and too fast continuous expansion is harmful.

Humans↗
PubMed2001

[Survey on the growth of interpupillary distance of Chinese children aged 5 to 17 years].

OBJECTIVE: To investigate the interpupillary distance (IPD) of Chinese children for stipulating the sizes for children spectacle frames. METHOD: The IPD of 10171 children aged 5 to 17 years old was measured with a caliper in four cities. RESULTS: The IPD was positively correlated with the age increase from 5 to 17 years. The IPD in males was larger than that in females. The differences of IPD between males and females in the age groups of 5 to 9 and 10 to 15 years were statistically significant (F = 400.97, P < 0.01). CONCLUSIONS: There are two peak periods of the growth of IPD in Chinese children at 5 to 9 and 10 to 15 years. The IPD in males reaches adult level at age 15 and in females at age 13. The differences of the IPD between male and female and among 4 cities have no practical meaning in stipulating the sizes of children spectacle frames.

Adolescent↗
PubMed2000

A mouse model of galactose-induced cataracts.

Galactokinase (GK; EC 2.7.1.6) is the first enzyme in the metabolism of galactose. In humans, GK deficiency results in congenital cataracts due to an accumulation of galactitol within the lens. In an attempt to make a galactosemic animal model, we cloned the mouse GK gene (Glk1) and disrupted it by gene targeting. As expected, galactose was very poorly metabolized in GK-deficient mice. In addition, both galactose and galactitol accumulated in tissues of GK-deficient mice. Surprisingly, the GK-deficient animals did not form cataracts even when fed a high galactose diet. However, the introduction of a human aldose reductase transgene into a GK-deficient background resulted in cataract formation within the first postnatal day. This mouse represents the first mouse model for congenital galactosemic cataract.

Aldehyde Reductase↗
PubMed2000

P47(phox)-deficient NADPH oxidase defect in neutrophils of diabetic mouse strains, C57BL/6J-m db/db and db/+.

Deficiencies in neutrophil NADPH oxidase proteins have been demonstrated in humans with chronic granulomatous disease. However, no spontaneous mutation in murine NADPH oxidase has been reported. In this study we report that neutrophils from the diabetic mouse strains, C57BL/6J-m heterozygous lean (lepr(db/+)) and homozygous obese (lepr(db/db)) mice produced no superoxide on stimulation. An absence of intact p47(phox) but not other oxidase proteins was observed in both mouse strains through the use of immunoblotting. Molecular analysis by reverse transcriptase-polymerase chain reaction identified three abnormal p47phox mRNA transcripts. Sequencing of genomic DNA of p47(phox) revealed a point mutation at the -2 position of exon 8, which is consistent with aberrant splicing of the p47(phox) transcript. These results indicate that the C57BL/6J-m db/db and db/+ mice are the first spontaneously derived murine model of NADPH oxidase deficiency involving a p47(phox) mutation.

Animals↗
PubMed1999

MPTP-Induced pallidal lesions in rhesus monkeys.

Dopamine neurons in the substantia nigra of the midbrain are the primary neuronal population affected by 1-methyl-4-phenyl-1,2,3, 6-tetrahydropyridine (MPTP) toxicity, which produces the pathological and behavioral features of Parkinson's disease in nonhuman primates and man. We have identified another injury site in magnetic resonance imaging (MRI) brain scans in 13 of 37 rhesus monkeys taken 10-12 months after administration of this neurotoxin via the right carotid artery. Focal lesions, ranging in volume from 6.75 to 60 mm3 in the rostral globus pallidus region, were seen on the right side of the brain in these 13 animals in addition to the midbrain effects. While no significant differences were seen between globus pallidus lesioned and nonlesioned animals in the severity of MPTP-induced parkinsonian symptoms, the response to levodopa was muted in pallidal-lesioned animals. To confirm the role of neurotoxicity in producing the lesions, brain scans from an additional 12 monkeys were evaluated during the acute period following exposure to either MPTP (n = 6) or saline (n = 6). Focal lesions in the rostral globus pallidus were seen as early as 2-4 h following a carotid artery infusion in two of six MPTP recipients, but no evidence of injury was seen in saline recipients. The globus pallidus includes important components of the neural circuitry regulating motor functions. The present results indicate that in addition to midbrain dopamine neurons, a focal region of the rostral globus pallidus is selectively vulnerable to MPTP toxicity.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed1999

[A case of fetal valproate syndrome with intractable wheezing due to submucosal tumor below the vocal cord].

A full-term baby was born to an epileptic mother treated with two anti-epileptic drugs, sodium valproate and phenobarbital, throughout the pregnancy. She was given no information about the risk of teratogenesis of these drugs. At birth the patient was hypotonic and had clinical features specific for the fetal valproate syndrome. After a viral infection at three months of age, he had intractable and persistent wheezing. Suspecting the presence of congenital respiratory tract abnormality, we performed tracheobronchoscopy, which revealed a relatively big submucosal tumor on the left trachial wall below the vocal cord. Dyspnea and wheezing were remarkably improved by tracheolaryngotomy, but he died suddenly and unexplainedly at seven months of age.

Abnormalities, Drug-Induced↗
PubMed1999

[The clinical features of multiple-trauma patients APACHE II score system].

The clinical features of 76 multiple-trauma patients in the intensive care unit were observed with acute physiology and chronic health evaluation (APACHE II) system. The results showed that the mean value of APACHE II scores in 76 patients was 18.4; the mean duration of staying at the ICU was 91.5 hours. Six patients died in the ICU (7.9%), 13 patients were complicated with MODS (17.1%), and 10 patients developed ARDS (13.2%). As APAHCE II scores increased, the duration of the patient staying at the ICU lengthened and the mortality went up.

APACHE↗
PubMed1998

The role of p38 MAP kinase in TGF-beta1-induced signal transduction in human neutrophils.

Transforming growth factor-beta 1 (TGF-beta 1) is the strongest chemoattractant yet described for human neutrophils. It activates neither phospholipase C nor phospholipase D. It does not induce rises in intracellular calcium, degranulation, or superoxide production. The signaling pathways utilized by TGF-beta 1 are largely unknown. This report demonstrates that TGF-beta 1 activates p38 MAP kinase. The kinase inhibitor SB203580 blocks the chemotactic responses as well as actin polymerization induced by TGF-beta 1. Potential cellular targets of the p38 MAP kinase pathway which could mediate these function are discussed.

Actins↗
PubMed1998

Construction and application of MCBL plate for facilitation of chromosome recombination in fungi.

A medium with camphor and benomyl MCBL plate was designed and constructed based on the proposed mechanism that d-camphor could induce the fusion of nuclear membrane while benomyl could induce the nondisjunctional recombination of chromosome in fungi. This so-called co-induction plate consisted of 0.1% d-camphor (W/V) and 0.5 microgram/L benomyl contained in Czapek's minimal medium. The precautions to be taken in the construction procedure of this plate was described in detail. One typical example of intergeneric fusion-cross, Aspergillus niger x Trichoderma reesei, was investigated, comparing the ratios of genotypes and phenotypes of fusant progenies produced by the co-induction of MCBL plate and by the step-by-step induction with camphor and benomyl separately. The results showed that the heterodiploid state was extremely transient and the recombinant haploid was hardly obtained when induced by the routine step-by-step method, whereas the ratios of apparent diplodization and nondisjunctional recombinant haplodization among all types of varied segregates on MCBL plate were greatly improved, compared with those on the routine plates containing single reagents, which indicated that the transient heterodiploid could be grasped and transformed further into nondisjunctional recombinant haploid when co-induced on the MCBL plate. The age of regenerated mycelium to be induced was found to have a dominant influence on the co-induction effects of MCBL plate. The mechanism of co-induction by MCBL plate and its promising applications were discussed.

Aspergillus niger↗
PubMed1998

[Study on the effect of human herpesvirus 6 on replication of Epstein-Barr virus].

OBJECTIVE: To examine the effect of human herpesvirus 6(HHV-6) on the replication of Epstein-Barr virus (EBV) in cell lines. METHODS: Both EBV-infected Raji cells and EBV-transformed lymphoblastoid cell lines (LCL) were infected with HHV-6. Immunofluoresence assay (IFA) with monoclonal antibodies (MAb) against HHV-6 was applied to confirm the infection of HHV-6 in the two cell lines. Expression of EBV antigen was examined by IFA using human anti-EBV serum. RESULTS: Following HHV-6 infection, cytopathic effects (CPE) were observed in Raji cells but not in LCL. HHV-6 were detected in both cell lines by IFA with anti-HHV-6 MAb, but not in controls. EBV antigens were detected by IFA with human serum against EBV in both HHV-6 infected cell lines. CONCLUSION: Data in this study suggest that HHV-6 promotes the expression of EBV antigen and may contribute to the pathogenesis of nasopharyngeal carcinoma in cooperation with EBV.

Antigens, Viral↗
PubMed1998

[The intergeneric compatibility of heredity and expression for cellulase genomes between Aspergillus niger and Trichoderma reesei].

By using the developed display techniques of cellulase isozymes and the RAPD-PCR analysis guided by a deduced universal sequence of cellulase genes, the polymorphisms of genomic DNA fingerprints and cellulase isozymes were compared among three typical stable recombinants (3a, 3b, A7-1) and their two parents (Aspergillus niger AMS11, Trichoderma reesei QM9414) in order to provide the molecular evidence of gene recombination, to demonstrate the compatibility of heredity and expression of intergeneric genomes, and to assay on the molecular fundamentals of hybridization dominance. The results showed that in these recombinant strains the recombinantal fingerprints of genomic DNA could be stablly hereditary and the expression of recombinantal CMCase (carboxymethylcellulase) and beta GLase (beta-glucosidase) could be compatibly enhanced. The diversity of molecular fundamentals of cellulase hybridization dominance were (1) the compatible co-existence and enhanced expression of some hereditary beta GLase-coding genes from two parents in recombinant 3b; and (2) the compatibly enhancement of expression between the hereditary genes encoding beta GLase and CMCase from two parents, resulting in the dramatic increase of proteins of corresponding isozymes in recombinants 3a and A7-1. Based on these, a proposal model for the double synergism on cellulase activity in vitro and on its biosynthesis in vivo mediated by beta GLase was suggested. A practical method for assaying on the molecular fundamentals and the stability of hybridization dominance of recombinants was thereby established in this study.

Aspergillus niger↗
PubMed1997

LSP1 is the major substrate for mitogen-activated protein kinase-activated protein kinase 2 in human neutrophils.

In intact cells, mitogen-activated protein kinase-activated protein (MAPKAP) kinase 2 is rapidly activated by various cytokines, stresses, and chemotactic factors. The small heat shock protein p27 has been shown to be a substrate for MAPKAP kinase 2. Recently, we identified a novel substrate, designated p60, for MAPKAP kinase 2 in human neutrophils (Zu, Y.-L., Ai, Y., Gilchrist, A., Labadia, M. E., Sha'afi, R. I., and Huang, C.-K. (1996) Blood 87, 5287-5296). To further understand the signaling pathway of MAPKAP kinase 2, we have purified p60 from a heat-treated neutrophil lysate by DEAE-cellulose chromatography and SDS-polyacrylamide gel electrophoresis. Microsequencing of five peptides derived from purified p60 indicates that p60 is lymphocyte-specific protein 1 (LSP1). Furthermore antibodies specific for human and mouse LSP1 react with human and mouse p60. The sequence of human LSP1 indicates two serine residues at positions 204 and 252 as potential phosphorylation sites. The amino acid sequences surrounding these two sites are in agreement with the consensus sequence (Xaa-Xaa-Hyd-Xaa-Arg-Xaa-Xaa-Ser-Xaa-Xaa) for phosphorylation by MAPKAP kinase 2. Both serine residues in human LSP1 and the corresponding conserved serine residues in mouse LSP1 are in the basic C-terminal F-actin binding domain. Various fusion proteins of wild type and truncated mouse LSP1 with glutathione S-transferase were tested for their capacity to be phosphorylated by MAPKAP kinase 2. The results indicate that LSP1 is a substrate for MAPKAP kinase 2 in vitro and that the phosphorylation sites are located in the basic C-terminal domain of LSP1. Because both the small heat shock proteins and LSP1 are F-actin binding proteins, these results suggest a role for MAPKAP kinase 2 in the regulation of cytoskeletal structure or function.

Amino Acid Sequence↗