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Biomedical subjects

J Song

Publications and source records attributed to J Song.

At least 217 records · Page 12Linked to original sources
PubMed1999

[Ocular pharmacokinetics of pilocarpine micron emulsion in rabbits].

OBJECTIVE: To compare the pharmacokinetics of pilocarpine micron emulsion with generic pilocarpine solution in the aqueous humor. METHODS: 60 albino rabbits were used and were divided into 20 groups, each consisting of 3 animals. 10 groups received 2% generic pilocarpine 50 microl as controls; 10 groups received 50 microl of 2% pilocarpine micron emulsion in the conjunctival sac. The aqueous humor was withdrawn at 5, 10, 30, 40, 60, 90, 120, 180, 240 and 360 min. after instillation. The drug was extracted from aqueous humor with dichloromethane. The drug was analyzed by reversed phase high pressure liquid chromatography (HPLC). RESULTS: Pilocarpine micron emulsion therapy gave higher aqueous humor concentration of the drug than drops at all time periods tested except 5 min. time point (P = 0.0003 - 0.042). The area under curve of micron emulsion was 3 times as much as that of drops. There was a two-fold increase in ocular bioavailability of pilocarpine due to the therapy with micron emulsion. Measurable amounts of drug following 2% micron emulsion were still observed at 360 min. while drug levels at 180 min. following 2% drop therapy were nil. CONCLUSION: Our study results demonstrated significantly increase in ocular bioavailability of pilocarpine due to the therapy with micron emulsion. Our finding indicates that a novel topical preparation of pilocarpine incorporated in micron emulsion might serve as a long acting antiglaucoma agent, and less frequent applications are necessary with it than with conventional drops.

Animals↗
PubMed1999

[Significance of detection of HBV-DNA and CMV-DNA by polymerase chain reaction in screening mothers' milk].

Hepatitis B virus(HBV) DNA and cytomegalovirus DNA in the colostrum of lying-in women were detected by polymerase chain reaction for the safety of mothers' milk in the milk bank. The results showed that: 1. HBV-DNA was not found in the milk of women with negative serological markers of the virus, while in the milk of women with positive marker of HBsAg, HBeAg and HBcAb, the positive rate of HBV-DNA was 81.25%, in the milk of mothers with positive marker of HBsAg, HBcAb and HBeAb, the positive rate was 45.24%, in the milk of women only with HBcAb and HBeAb positive, the rate was 23.08%. 2. The specific amplified products of CMV DNA in the milk were obtained in 42.80%-70.00% women whose CMV IgM antibody was positive. These findings suggest that the excretion of viruses would increase in mothers with active virus replication, and the viruses would be transmitted to newborns by milk. The authors think that only the milk from the mothers with both negative serological markers and negative PCR of the viruses can be collected and stored in the milk bank. PCR is a specific and sensitive technique which can be used to monitor the safety of mothers' milk. In this paper, the authors have presented some suggestions about how to give breast-feeding and protect newborns whose mothers are various status of virus secretion in the milk.

Adult↗
PubMed1999

[Effect of Gastrodia on rotation induced motion sickness in mice].

OBJECTIVE: To observe the effect of Gastrodia on motion sickness induced by rotation in mice. METHOD: Clockwise and anticlockwise accelerated rotations up to 180 degrees/s for 10 min were used to induce symptoms of motion sickness such as condition taste aversion (CTA), decrease of spontaneous locomotion and impaired ability of space identification in water-maze. RESULT: Gastrodia could improve the response of CTA, increase spontaneous locomotion, and enhance the ability of learning and memory in water-maze in mice after the rotation. CONCLUSION: Symptoms of motion sickness induced by rotation could be improved by Gastrodia treatment.

Animals↗
PubMed1999

[The properties of new affinity adsorbent for adsorbing the cycle immune complex in blood].

This study was designed to select an affinity adsorbent from 5 kinds of adsorbents available. The adsorbent AA3 was found being specific to the adsorption of pathologic cycle immune complex (CIC). The physical properties such as specific surface area, proe volume and average pore diameter of adsorbents were determined. A discussion on the factors that affect the adsorption of CIC is also presented in this paper.

Adsorption↗
PubMed1999

[The development and clinical application of a multipurpose neuroendoscope].

The multipurpose rigid neuroendoscope MGE-4 has been developed with the application of the self-focussing lens technology. We have been using it to examine and treat 10 neurosurgical patients who suffered from tumours, hydrocephalus, intracerebral haematomas of head injury and hypertensive cerebral haemorrhage. The short-term effect was satisfactory and there was no operative complications. It is considered that Model MGE-4 with the accessories can be used safely for the brain functional subcortical lesion or the deep-seated cystic lesions and haematomas.

Adult↗
PubMed1999

Sensory examination. Comparison of instruments.

Quantitative sensory testing techniques have been developed to yield more consistent and objective measures of sensory deficits than can be obtained through the traditional clinical evaluation of the patient. At the same time, these measures are less invasive and uncomfortable than typical electrophysiologic studies. This article provides an overview of the principles of quantitative sensory testing, and discusses currently available instruments.

Foot Diseases↗
PubMed1998

BAG-1, a negative regulator of Hsp70 chaperone activity, uncouples nucleotide hydrolysis from substrate release.

Molecular chaperones influence the process of protein folding and, under conditions of stress, recognize non-native proteins to ensure that misfolded proteins neither appear nor accumulate. BAG-1, identified as an Hsp70 associated protein, was shown to have the unique properties of a negative regulator of Hsp70. Here, we demonstrate that BAG-1 inhibits the in vitro protein refolding activity of Hsp70 by forming stable ternary complexes with non-native substrates that do not release even in the presence of nucleotide and the co-chaperone, Hdj-1. However, the substrate in the BAG-1-containing ternary complex does not aggregate and remains in a soluble intermediate folded state, indistinguishable from the refolding-competent substrate-Hsp70 complex. BAG-1 neither inhibits the Hsp70 ATPase, nor has the properties of a nucleotide exchange factor; instead, it stimulates ATPase activity, similar to that observed for Hdj-1, but with opposite consequences. In the presence of BAG-1, the conformation of Hsp70 is altered such that the substrate binding domain becomes less accessible to protease digestion, even in the presence of nucleotide and Hdj-1. These results suggest a mechanistic basis for BAG-1 as a negative regulator of the Hsp70-Hdj-1 chaperone cycle.

Adenosine Triphosphatases↗
PubMed1998

Association between apolipoprotein(a) polymorphism and Lp(a) levels in Koreans.

In view of the clinical importance of lipoprotein(a) [(Lp(a)] in coronary artery disease (CAD), we investigated the apo(a) size polymorphism, sequence polymorphisms of five base repeats [(TTTTA)n] in the noncoding region, and of Met/Thr in the coding region of the apolipoprotein(a) [apo(a)] gene. The apo(a) polymorphisms were examined in 184 Korean patients with CAD and 121 healthy subjects. In size polymorphism, there was an inverse association between plasma Lp(a) levels and the apo(a) isoforms in the CAD group (p < 0.005). For (TTTTA)n sequence polymorphism, subjects with the 8/8 genotype were most frequently observed in the two groups. Plasma Lp(a) levels showed a significant difference between the 8/5 versus the 8/8 genotype in the CAD group. On the other hand, Lp(a) levels varied significantly among the genotypes of a Met/Thr polymorphism in normal controls (P < 0.01). The heterozygous genotype had an intermediate level of Lp(a) between the two homozygous genotypes, thereby showing gene dosage effect. Thus, it is possible that the apo(a) polymorphisms are responsible for variations in the Lp(a) levels.

Adult↗
PubMed1998

The topology of VDAC as probed by biotin modification.

The outer membrane of mitochondria contains channels called VDAC (mitochondrial porin), which are formed by a single 30-kDa protein. Cysteine residues introduced by site-directed mutagenesis at sites throughout Neurospora crassa VDAC (naturally devoid of cysteine) were specifically biotinylated prior to reconstitution into planar phospholipid membranes. From previous studies, binding of streptavidin to single biotinylated sites results in one of two effects: reduced single-channel conductance without blockage of voltage gating (type 1) or locking of the channels in a closed conformation (type 2). All sites react with streptavidin only from one side of the membrane. Here, we extend this approach to VDAC molecules containing two cysteines and determine the location of each biotinylated residue with respect to the other within the membrane. When a combination of a type 1 and a type 2 site was used, each site could be observed to react with streptavidin. Two sets of sites located on opposite surfaces of the membrane were identified, thereby establishing the transmembrane topology of VDAC. A revised folding pattern for VDAC, consisting of 1 alpha helix and 13 beta strands, is proposed by combining these results with previously obtained information on which sites are lining the aqueous pore.

Amino Acid Sequence↗
PubMed1998

Human genes for KNSL4 and MAZ are located close to one another on chromosome 16p11.2.

KNSL4 (Kid; kinesin-like DNA-binding protein) is a member of the kinesin family that is involved in spindle formation and the movements of chromosomes during mitosis and meiosis. Myc-associated zinc finger protein (MAZ) participates in both the initiation and the termination of transcription of target genes. We isolated genomic DNA clones that encoded KNSL4 and MAZ from a human cosmid library. Sequence analysis revealed that the two genes were very close to one another. The distance between the two genes was only 1. 2 kb, and this intervening 1.2-kb region was extremely GC-rich. The gene for KNSL4 spanned 16 kb and consisted of 14 exons and 13 introns, while the gene for MAZ spanned 6 kb and consisted of 5 exons and 4 introns. The two genes were mapped to chromosome 16p11.2 by fluorescence in situ hybridization.

Chromosome Mapping↗
PubMed1998

Genomic organization and expression of a human gene for Myc-associated zinc finger protein (MAZ).

We have cloned and characterized the genomic structure of the human gene for Myc-associated zinc finger protein (MAZ), which is located on chromosome 16p11.2. This gene is transcribed as an mRNA of 2.7 kilobases (kb) that encodes a 60-kDa MAZ protein. A 40-kb cosmid clone was isolated that includes the promoter, five exons, four introns, and one 3'-untranslated region. All exon-intron junction sequences conform to the GT/AG rule. The promoter region has features typical of a housekeeping gene: a high G + C content (88. 4%); a high frequency of CpG dinucleotides, in particular within the region 0.5 kb upstream of the site of initiation of translation; and the absence of canonical TATA and CAAT boxes. An S1 nuclease protection assay demonstrated the presence of multiple sites for initiation of transcription around a site 174 nucleotides (nt) upstream of the ATG codon and such expression was reflected by the promoter activity of a MAZ promoter/CAT (chloramphenicol acetyltransferase) reporter gene. Cis-acting positive and negative elements controlling basal transcription of the human MAZ gene were found from nucleotides (nt) -383 to -248 and nt -2500 to -948. Moreover, positive and negative autoregulatory elements were also identified in the regions from nt -248 to -189 and from nt -383 to -248 after co-transfection of HeLa cells with plasmids that carried the MAZ promoter/CAT construct and the MAZ-expression vector. Our results indicate that the 5'-end flanking sequences are responsible for the promoter activities of the MAZ gene.

Amino Acid Sequence↗
PubMed1998

A developmental stage-specific promoter directs germline transcription of D beta J beta gene segments in precursor T lymphocytes.

The tissue- and stage-specific assembly of Ag receptor genes is regulated by transcriptional control elements positioned within Ig and TCR loci. To further understand the role of cis-acting elements in these regulatory mechanisms, we have characterized a transcriptional promoter that drives germline expression of TCR beta gene segments in vivo. The activity of this promoter, termed PD beta, is restricted to a highly conserved 400-bp region located directly upstream from D beta 1-coding sequences. Maximal PD beta activity requires a TATA element situated within the D beta 1 recombination signal sequences and consensus binding sites for the ubiquitous SP1 and the T cell-specific GATA-3 transcription factors. When linked to active enhancer elements, PD beta directs transcription in most cell types; however, the TCR beta enhancer (E beta) stimulates PD beta function specifically in precursor T lymphocytes. These findings suggest that PD beta/E beta interactions may contribute to differential regulation of regions within the TCR beta locus during thymocyte development.

Animals↗
PubMed1998

Contribution of individual residues to formation of the native-like tertiary topology in the alpha-lactalbumin molten globule.

Molten globules are partially folded forms of proteins that have native-like secondary structure and a compact geometry, but often without rigid, specific side-chain packing. Recently, the molten globule of alpha-lactalbumin (alpha-LA) has been shown to adopt a native-like tertiary topology, mainly localized in the alpha-helical domain. This native-like topology is reflected by the high effective concentration (Ceff) for formation of the 28-111 disulfide bond, which is approximately 10 to 40 times higher than the Ceff for formation of any non-native disulfide bond in the alpha-helical domain. In order to understand the mechanism for formation of the native-like tertiary topology, we substituted alanine for each of the 23 buried residues in the alpha-helical domain of alpha-LA and determined the effect of these substitutions on the Ceff for formation of the 28-111 disulfide bond. Our results indicate that a subset of hydrophobic residues is most important for formation of the native-like topology. These residues form a densely packed core in the three-dimensional structure of alpha-LA. In contrast, the less important residues consist of both hydrophobic and hydrophilic amino acids located at peripheral positions. These results suggest that a relatively small number of hydrophobic residues may be sufficient for specifying the overall structure of a protein during early stages of protein folding.

Cysteine↗
PubMed1998

Isolation and mapping of a family of putative zinc-finger protein cDNAs from rice.

To understand the functions of rice homologues of the Arabidopsis flowering-time gene CONSTANS (CO) and salt-tolerance gene STO, we performed a similarity search of the single-run sequence data of cDNA clones accumulated by the Rice Genome Research Program, and isolated seven rice cDNA clones (S3574, C60910, S12569, R2931, R1479, R1577, and E10707) coding for proteins containing one of two zinc-finger-like motifs. Comparison of the deduced amino acid sequences between these cDNAs and the CO gene revealed significant similarities (46%-61%) in the region of zinc-finger motifs. A domain having a high content of basic amino acids at the C-terminus of the CO protein was found in the corresponding region of proteins predicted by from cDNAs S3574, C60910, and S12569. Two amino acid sequences, "CCADEAAL" and "FCV(L)EDRA," which were present inside each zinc-finger in the Arabidposis regulatory protein STO, were also found in each of the two zinc-finger regions of proteins predicted from cDNAs R2931, R1479, R1577, and E10707. Using restriction fragment length polymorphism (RFLP) linkage analysis, we determined the chromosomal location of the seven cDNA clones. The position of R2931 on the RFLP linkage map was closely linked to Hd-3, one of the putative quantitative trait loci (QTL) controlling heading date in rice.

Amino Acid Sequence↗
PubMed1998

Successful recovery of the normal electrophysiological properties of PorB (class 3) porin from Neisseria meningitidis after expression in Escherichia coli and renaturation.

Neisseria meningitidis PorB class 3 porins obtained either from native membranes (wild-type) or recovered from inclusion bodies following expression in Escherichia coli (recombinant), have been reconstituted into solvent-free planar phospholipid membranes. The wild-type and recombinant porins exhibited the same single-trimer conductance (1-1.3 nS in 200 mM NaCl), tri-level closure pattern, characteristic of functional channel trimers, and pattern of insertion into planar membranes. Both proteins were open at low voltages and displayed two voltage-dependent closure processes, one at positive and the other at negative potentials. Both showed asymmetric voltage dependence such that one gating process occurred at lower voltages (Vo=15 mV) than the other (Vo=25 mV). The sign of the potential that resulted in closure at low voltages varied from membrane to membrane indicating that they may have the property of auto-directed insertion (in analogy to the mitochondrial channel, VDAC). In the case of the recombinant porin, the steepness of the voltage dependence of one gating process was slightly less (n=1.3) than that observed for the other process or for the wild-type channel (n=1.5-1.7). Both channels have a high (40%) probability of closure even at 0 mV. While both channels show a slight selectivity for Cl- over Na+, the selectivity of the recombinant porin is a bit higher (permeability ratio of 2.8 vs. 1.6) as measured using a 2-fold salt gradient. Thus, the method employed to refold the recombinant porin was successful in not only restoring wild-type structure [H.L. Qi, J.Y. Tai, M.S. Blake, Expression of large amounts of Neisserial porin proteins in Escherichia coli and refolding of the proteins into native trimers, Infect. Immun. 62 (1994) 2432-2439; C.A.S.A. Minetti, J.Y. Tai, M.S. Blake, J.K. Pullen, S.M. Liang, D.P. Remeta, Structural and functional characterization of a recombinant PorB class 2 protein from Neisseria meningitidis. Conformational stability and porin activity, J. Biol. Chem. 272 (1997) 10710-10720] but also the overall electrophysiological function.

Bacterial Outer Membrane Proteins↗
PubMed1998

Linkage disequilibrium of the Apo AI-CIII-AIV gene cluster and their relationship to plasma triglyceride, apolipoprotein AI and CIII levels in Koreans.

More than 20 different RFLPs have been described in the apo AI-CIII-AVI gene cluster and their association with several dyslipidemias has been claimed in different populations. So far, however, the results of their association have been largely inconclusive. We analyzed six previously described RFLPs (Paul-Hayase et al., 1992) in the apo AI-CII-AIV gene cluster by using PCR-amplified DNAs in 132 healthy subjects to document the relationship between the RFLPs and dyslipoproteinemias. The polymorphic sites were located in the promoter region of the apo AI gene (G to A substitution, MspI), in the 3' flanking region of the apo AI gene (PstI), in the 3' noncoding region of the apo CIII gene (SstI), in the first intron of the apo CIII gene (PvuIIa), in the intergenic region of the apo CIII and apo AIV genes (PvuIIb), and in the second intron of the apo AIV gene (XbaI), respectively. The allele frequencies of PstI polymorphism showed no ethnic difference. However, in G to A substitution sites (MspI), Koreans had a lower G allele frequency than that of Caucasians. Among Oriental ethnic groups there were no significant differences in the allele frequencies of SstI and PvuIIa RFLPs, whereas significant differences existed between individuals of Oriental, Caucasian, and/or African origins. Koreans were monomorphic for PvuIIb and XbaI restriction sites. Pairwise linkage disequilibrium analysis revealed two pairs of significant negative linkage disequilibriums (MspI-SstI and SstI-PvuIIa). Although there were no statistical significances, the S2 allele of SstI polymorphism and the G allele of MspI polymorphism seemed to be associated with hypertriglyceridemia. Thus linkage of the G allele of MspI polymorphism and the S2 allele of SstI polymorphism could give an additive effect on an increment of triglyceride levels. We did not find any association between the SstI polymorphism and apo CIII levels. In conclusion, there were no statistically significant relationships detected between the apo AI-CIII-AVI gene cluster polymorphisms and the levels of various lipid parameters.

Adolescent↗
PubMed1998

p300 and ATF-2 are components of the DRF complex, which regulates retinoic acid- and E1A-mediated transcription of the c-jun gene in F9 cells.

Transcriptional activation of the c-jun gene is a critical event in the differentiation of F9 cells. In our previous studies we characterized an element [differentiation response element (DRE)] in the c-jun promoter that is both necessary and sufficient to confer the capacity for differentiation-dependent up-regulation. This element binds the differentiation regulatory factor (DRF) complex, of which one component is the adenovirus E1A-associated protein p300. We have now identified activation transcription factor-2 (ATF-2) as a DNA-binding subunit of the DRF complex. p300 and ATF-2 interact with each other in vivo and in vitro. The bromodomain and the C/H2 domain of p300 mediate the binding to ATF-2, which in turn requires a proline-rich region between amino acids 112 and 350 for its interaction with p300. The phosphorylation of the serine residue at position 121 of ATF-2 appears to be induced by protein kinase C alpha (PKC alpha) after treatment of cells with retinoic acid (RA) or induction with E1A. In cotransfection assays, wild-type ATF-2 enhanced the transcription of an E2/tk-luciferase construct, in conjunction with p300-E2. However, a mutant form of ATF-2 with a mutation at position 121 (pCMVATF-2(Ser121-Ala)) did not. These results suggest that ATF-2 and p300 cooperate in the control of transcription by forming a protein complex that is responsive to differentiation-inducing signals, such as RA or E1A, and moreover, that the phosphorylation of ATF-2 by PKC alpha is probably a signaling event in the pathway that leads to the transactivation of the c-jun gene in F9 cells.

Activating Transcription Factor 2↗