Developmental biology. Vesicles and the spinal cord.
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Animals↗
Biomedical subjects
J Jeong
Publications and source records attributed to J Jeong.
Rat embryo fibroblasts require both the cell-binding and the heparin-binding domains of fibronectin for survival.
Fibronectin (FN) is known to transduce signal(s) to rescue cells from detachment-induced apoptosis (anoikis) through an integrin-mediated survival pathway. However, the functions of individual FN domains have not been studied in detail. In the present study we investigated whether the interaction of the cell-binding domain of FN with integrin is sufficient to rescue rat embryo fibroblasts (REFs) from detachment-induced apoptosis. REFs attached and spread normally after plating on substrates coated with either intact FN or a FN fragment, FN120, that contains the cell-binding domain but lacks the C-terminal heparin-binding domain, HepII. REFs on FN maintained a well-spread fibroblastic shape and even proliferated in serum-free medium at 20 h after plating. In contrast, previously well-spread REFs on FN120 started losing fibroblastic shape with time and detached from FN120-coated plates after approx. 8 h. Nuclear condensation indicated apototic cell death. This was due to the decreased activity/stability of focal adhesion kinase (pp125FAK) in the absence of HepII domain. A peptide in the HepII domain [peptide V, WQPPRARI (single-letter amino acid codes)], which has previously been implicated in cytoskeletal organization, rescued apoptotic changes. Consistently, pp125FAK phosphorylation was increased, and both cleavage of pp125FAK and activation of caspase 3 on FN120 were partly blocked by peptide V. Thus the interaction of the cell-binding domain with integrin has a major role in cell survival but is itself not sufficient for cell survival. One or more additional survival signals come from the HepII domain to regulate pp125FAK activity/stability.
Amino Acid Sequence↗
Effect of total sleep deprivation on the dimensional complexity of the waking EEG.
STUDY OBJECTIVES: Sleep deprivation can affect the waking EEG that may reflect information processing of the brain. We examined the effect of total sleep deprivation (TSD) on nonlinear dynamics of the waking EEG. DESIGN: Paired-group design. SETTING: A sleep disorders laboratory in a hospital. PARTICIPANTS: Twenty healthy male volunteers. INTERVENTIONS: Waking EEG data were recorded from subjects with eyes closed after (a) an 8-hour night's sleep and (b) TSD for 24 hours. The dimensional complexity (D2), as a nonlinear measure of complexity, of the EEG after a full night sleep were compared with those of the EEG after TSD. MEASUREMENTS AND RESULTS: The sleep-deprived states had lower D2 values at three channels (P4, O2, and C3) than normal states. CONCLUSIONS: TSD results in the decrease of complexity in the brain, which may imply sub-optimal information processing of the cerebral cortex. We suggest that the investigation of the relation between nonlinear dynamics of the waking EEG induced by TSD and cognitive performance may offer fruitful clues for understanding the role of sleep and the effects of sleep deprivation on brain function.
Adult↗
Localization and characterization of acharan sulfate in the body of the giant African snail Achatina fulica.
Acharan sulfate is a glycosaminoglycan (GAG), having the structure -->4)-2-acetamido-2-deoxy-alpha-D-glucopyranose(1-->4)-2-sulfo-alpha-L-idopyranosyluronic acid (1-->, isolated from the body of the giant African snail Achatina fulica. This GAG represents 3-5% of the dry weight of this snail's soft body tissues. Frozen sections and polyester wax sections of the snail's body were stained by Alcian blue-periodic acid-Schiff's reagent (PAS) to localize acharan sulfate. Alcian blue staining indicated that GAG was mainly secreted into the outer surface of the body from internal granules. A highly mucous material was collected and treated and the acharan sulfate was recovered by ethanol and cetyl pyridinium chloride precipitation. Crude acharan sulfate was purified by DEAE-Sephacel ion-exchange chromatography. Depolymerization of intact mucus and purified acharan sulfate fractions by heparin lyase II (heparitinase I) from Flavobacterium heparinum produced an unsaturated disaccharide as a major product, establishing the repeating unit of acharan sulfate. These results demonstrate that mucus in the granule and secreted to the outside of the body is composed entirely of acharan sulfate.
Alcian Blue↗
Mutual information analysis of the EEG in patients with Alzheimer's disease.
OBJECTIVE: Mutual information provides a measure of both the linear and nonlinear statistical dependencies between two time series. Cross-mutual information (CMI) is used to quantify the information transmitted from one time series to another, while auto mutual information (AMI) in a time series estimates how much on average the value of the time series can be predicted from values of the time series at preceding points. The aim of this study is to assess information transmission between different cortical areas in Alzheimer's disease (AD) patients by estimating the average CMI between EEG electrodes. METHODS: We recorded the EEG from 16 scale electrodes in 15 AD patients and 15 age-matched normal controls, and estimated the local, distant, and interhemispheric CMIs of the EEG in both groups. The rate of decrease (with increasing delay) of the AMI of the EEG was also measured to evaluate the complexity of the EEG in AD patients. RESULTS: The local CMI in AD subjects was lower than that in normal controls, especially over frontal and antero-temporal regions. A prominent decrease in information transmission between distant electrodes in the right hemisphere and between corresponding interhemispheric electrodes was detected in the AD patients. In addition, the AMIs throughout the cerebrums of the AD patients decreased significantly more slowly with delay than did the AMIs of normal controls. CONCLUSIONS: These results are consistent with previous findings that suggest the association of EEG abnormalities in AD patients with functional impairment of information transmission in long cortico-cortical connections.
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Nonlinear dynamic analysis of the EEG in patients with Alzheimer's disease and vascular dementia.
To assess nonlinear EEG activity in patients with Alzheimer's disease (AD) and vascular dementia (VaD), the authors estimated the correlation dimension (D2) and the first positive Lyapunov exponent (L1) of the EEGs in both patients and age-matched healthy control subjects. EEGs were recorded in 15 electrodes from 12 AD patients, 12 VaD patients, and 14 healthy subjects. The AD patients had significantly lower D2 values than the normal control subjects, (P < H > 0.05), except at the F7 and the O1 electrodes, and the VaD patients, except at the C3 and the C4 electrodes. The VaD patients had relatively increased values of D2 and L1 compared with the AD patients, and rather higher values of D2 than the normal control subjects at the F7, F4, F8, Fp2, O1, and O2 electrodes. The L1 values of the EEGs were also lower for the AD patients than for the normal control subjects, except in the O1 and the O2 channels, and for the VaD patients at all electrodes. The L1 values were higher for the VaD patients than for the normal control subjects (F3, F4, F8, O1, and O2). In addition, the authors detected that the VaD patients had an uneven distribution of D2 values over the regions than the AD patients and the normal control subjects, although the statistics do not confirm this. By contrast, AD patients had uniformly lower D2 values in most regions, indicating that AD patients have less complex temporal characteristics of the EEG in entire regions. These nonlinear analyses of the EEG may be helpful in understanding the nonlinear EEG activity in AD and VaD.
Aged↗
Differential regulation of the overlapping Kaposi's sarcoma-associated herpesvirus vGCR (orf74) and LANA (orf73) promoters.
Similar to that of other herpesviruses, Kaposi's sarcoma-associated herpesvirus (KSHV/HHV-8) lytic replication destroys the host cell, while the virus can persist in a latent state in synchrony with the host. During latency only a few genes are transcribed, and the question becomes one of what determines latent versus lytic gene expression. Here we undertake a detailed analysis of the latency-associated nuclear antigen (LANA [orf73]) promoter (LANAp). We characterized a minimal region that is necessary and sufficient to maintain high-level transcription in all tissues tested, including primary endothelial cells and B cells, which are the suspected natural host for KSHV. We show that in transient-transfection assays LANAp mimics the expression pattern observed for the authentic promoter in the context of the KSHV episome. Unlike other KSHV promoters tested thus far, LANAp is not affected by tetradecanoyl phorbol acetate or viral lytic cycle functions. It is, however, subject to control by LANA itself and cellular regulatory factors, such as p53. This is in contrast to the K14/vGCR (orf74) promoter, which overlaps LANAp and directs transcription on the opposite strand. We isolated a minimal cis-regulatory region sufficient for K14/vGCR promoter activity and show that it, too, mimics the regulation observed for the authentic viral promoter. In particular, we demonstrate that its activity is absolutely dependent on the immediate-early transactivator orf50, the KSHV homolog of the Epstein-Barr virus Rta transactivator.
Animals↗
An estimation of the first positive Lyapunov exponent of the EEG in patients with schizophrenia.
We studied the complexity of the electroencephalogram (EEG) in schizophrenic patients by estimating the first Lyapunov exponent (L1), which might serve as an indicator of the specific brain function in schizophrenia. We recorded the EEG from 25 schizophrenic patients (12 male, 13 female; age=25.1+/-7.0 years) fulfilling DSM-IV criteria and 15 healthy controls (9 male, 6 female; age=27. 8+/-4.2 years) at 16 electrodes, different from previous studies which recorded the EEGs at limited electrodes. We employed a method with an optimal embedding dimension to calculate the L1s. For limited noisy data, this algorithm was strikingly faster and more accurate than previous ones. Our results showed that the schizophrenic patients had lower values of the L1 at the left inferior frontal and anterior temporal regions compared with normal controls. These results for L1 in non-linear analysis have some differences from those for power ratios in linear analysis. These suggest that the non-linear analysis of the EEGs such as the estimation of the L1 might be a useful tool in analyzing EEG data to explore the neurodynamics of the brains of schizophrenic patients.
Adolescent↗
Delayed interval delivery in multiple gestations.
Two multiple pregnancies with delayed delivery after expulsion of dead fetus are presented. Case 1: A woman with a twin pregnancy and one intrauterine fetal death at 20 weeks' gestation delivered a dead fetus at 27 weeks' gestation. She delivered a healthy male infant weighing 2430 g at 33 weeks' gestation (42 d after the delivery of the first twin). Case 2: A woman with quadruplets pregnancy (2 live fetuses, one empty sac, and one fetocide at 7 weeks' gestation) got a intrauterine fetal death at 21 weeks' gestation at one fetus among 2 live fetuses and delivered a dead fetus at 24 weeks' gestation. She delivered a healthy female infant weighing 2110 g at 33 weeks' gestation (58 d after the delivery of a dead fetus). On the basis of our experience and the review of literature, delayed delivery with careful observation of fetal and maternal condition is recommended for improved survival and decreased morbidity among latter-born siblings.
Adult↗
Genomic structure and promoter analysis of the mouse EphA8 receptor tyrosine kinase gene.
The gene encoding the mouse EphA8 receptor tyrosine kinase has been isolated from a mouse genomic library, and its complete genomic structure has been determined. This gene spans approximately 28 kb and consists of 17 exons. This gene structure is similar to the structure of the chick EphB2 (Cek5) gene, except for one intron present between the first two exons encoding the EphA8 kinase domain. This difference may reflect an evolutionary divergence of the catalytic domain between EphA and EphB subgroup receptors. The site for transcription initiation has been mapped to the 19th nucleotide upstream from the translation start codon ATG. A feature of this gene is an unmethylated CpG island spanning exon 1 and the flanking sequence. The putative promoter of the EphA8 gene lacks a TATA box and contains multiple copies of the sequence GGGCGG, the core sequence of the putative Sp1-binding site. The 3.5-kb upstream genomic region containing part of the first exon showed strong promoter activity in NG108-15 neuroblastoma cells but much less in 293T cells, suggesting that this fragment is sufficient for neural cell-directed promoter activity. By deleting the genomic region containing the five GC boxes, it was shown that the minimal promoter region is primarily comprised of five copies of the Sp1-binding site located upstream from the transcription initiation site. Finally, in situ RNA hybridization studies revealed a very specific pattern of EphA8 gene expression restricted to the rostral region of midbrain tectum during embryonic development. Isolation of a functional promoter for the EphA8 gene is a first step in understanding how expression of this gene is controlled at the molecular level.
Amino Acid Sequence↗
Rupture of the rectosigmoid colon with evisceration of the small bowel through the anus.
Spontaneous rupture of the rectosigmoid colon and herniation of the small intestine through the rupture site and eventual evisceration through the anus is a very rare event. In the literature, only 42 cases have been reported. The majority of them occurred in patients with rectal prolapse and one case was reported in association with a third-degree uterine prolapse. We experienced an 81-year-old female patient with rectal prolapse and second-degree uterine prolapse complicated by spontaneous perforation of the rectosigmoid colon and anal evisceration of the small intestine. Segmental resection of the nonviable small intestine, primary repair of the ruptured rectosigmoid colon, and sigmoid loop colostomy were performed, and the patient recovered well. In our patient, both rectal and uterine prolapses cooperatively damaged the anterior wall of the rectosigmoid colon and resulted in perforation. So, rectal and uterine prolapses should be treated before the complication develops. In this patient, uterine prolapse should be treated because of the recurrence of this rare episode.
Aged↗
Characterization of ephrin-A1 and ephrin-A4 as ligands for the EphA8 receptor protein tyrosine kinase.
The Eph receptors are the largest known family of receptor protein tyrosine kinases, which play important roles with their ligands called ephrin in the neural development, angiogenesis, and vascular network assembly. It was previously shown that ephrin-A2, -A3 and -A5 bind to, and activate the EphA8 receptor tyrosine kinase, respectively. In this study, we have examined if there are other additional ephrin ligands interacting with the EphA8 receptor tyrosine kinase expressed in NIH3T3 fibroblasts. For this purpose, we have constructed chimeric ephrin-A1, -A4, -B1, -B2 or -B3 ligands consisting of the Fc portion of human IgG fused to their carboxyl-terminus. Both ephrin-A1 and ephrin-A4 chimeric ligands efficiently bound to the EphA8 receptor expressed in NIH3T3 fibroblasts, whereas the transmembrane ligands including ephrin-B1, -B2 and -B3 did not. Additionally we have demonstrated that both the EphA8-TrkB chimeric receptor and the EphA8 receptor expressed in NIH3T3 fibroblasts are efficiently tyrosine-phosphorylated upon stimulating with epthin-A1 or -A4 but none of transmembrane ephrin-B proteins. These results strongly indicate that the EphA8 receptor functions exclusively as an glycosyl phosphatidylinositol (GPI)-linked ephrin ligand-dependent receptor protein tyrosine kinase.
3T3 Cells↗
Characterization of antithrombotic activity of lumbrokinase-immobilized polyurethane valves in the total artificial heart.
Thirty ng/mm2 lumbrokinase, a potent fibrinolytic enzyme, was immobilized in a Korean type total artificial heart (KORTAH) valve by photoreaction; polyallylamine was used as a photoreactive linker. Lumbrokinase-immobilized polyurethane valves were then fitted to the total artificial hearts of 3 healthy 50 kg lambs. In the control lamb, the valves were untreated; in one other, only valves on the right were treated; and in the remaining animal, only those on the left. Implants were in place for up to 3 days, and cardiac output was 5 L/min. To facilitate thrombus formation, low doses of heparin were administered. In the control lamb, thrombi was observed only in the inlet parts of the valves. In the other 2 experiments, thrombi formed in untreated control valves but not in lumbrokinase treated valves. The grade of thrombus formation in untreated valves was 1.06+/-1.37 versus 0+/-0 in the treated part by one-sided Student's t-test (p < 0.1). After implantation, fibrinolytic activity was only observed in treated valves by fibrin plate methods. The proteolytic activity of the treated valves was 3 times higher than that of untreated valves using the azocasein method. These data show that lumbrokinase treated polyurethane valves lead to decreased thrombus formation in vivo and that their biocompatibility is therefore greater than that of untreated valves.
Animals↗
Test for low-dimensional determinism in electroencephalograms.
We tested low-dimensional determinism in an electroencephalogram (EEG), based on the fact that smoothness (continuity) on an embedded phase space is enough to imply determinism within time series. A modified version of the method developed by Salvino and Cawley [Phys. Rev. Lett. 73, 1091 (1994)] was used. In our method, we chose a box randomly and then estimated the mean directional element in the box containing the d+1 data points, where d is the embedding dimension. The global average for the mean local directional elements over the boxes, W, is a measure for smoothness. The nonlinear noise reduction method developed by Sauer [Physica D 58, 193 (1992)] is then applied to the EEG. We also compared the results for the EEG with those for its surrogate data. We found that the W values for the noise-reduced EEG had stable values around 0.35, which means that the EEG is not a low-dimensional deterministic signal. However, this method may not be applicable to the time series generated from high-dimensional deterministic systems. We cannot exclude the possibility that the determinism in the EEG may be too high-dimensional to be detected with current methods.
Algorithms↗
Rahnella aquatilis sepsis in an immunocompetent adult.
Rahnella aquatilis, a rare enteric gram-negative rod which is infrequently isolated in immunocompromised patients, was isolated as a causative organism of sepsis in a 26-year-old immunocompetent male patient. The contaminated intravenous fluid was confirmed to be the source of the organism.
Adult↗
Expression of biliary antigen and its clinical significance in hepatocellular carcinoma.
In order to classify the hepatocellular carcinomas (HCCs) which had diverse clinicopathologic characteristics, we divided HCCs into two groups according to the expression of biliary antigen on the basis of the hypothesis that the hepatocyte and biliary epithelial cell originate from the same precursor cell, and then we investigated the clinical and pathologic characteristics in the two groups. Forty HCC cases with no preoperative treatment and at least two-year follow-up data were selected among 202 cases of HCC files from 1991 to 1995. Expression of biliary antigen (AE1, cytokeratin 19), p53, AFP, and Ki-67 in the tumor tissue were assessed by immunohistochemistry. Positive cytokeratin 19 was noted in one case (2.5%); AE1 was detected in 40% of patients; p53 was overexpressed in 20% of patients; and AFP was detected in 45% of patients. No statistical difference between the biliary antigen positive group (16 cases) and the negative group (24 cases) were noted in terms of mean age, sex, presurgical serum AFP level, Child class, and tumor size. HBsAg positive rate was 66.7% for the biliary antigen (-) group and 93.8% for the biliary antigen (+) group with a statistically significant difference (p = 0.048). The number of cases for Edmonson-Steiner grade I/II and III/IV were 15 and 9 in the biliary antigen (-) group, and 4 and 12 in the biliary antigen (+) group, respectively, with a statistically significant difference (p = 0.024). The 1, 3 and 5-year disease-free survival rates were 69.7, 40.9 and 40.9% for the biliary antigen (-) group and 73.7, 39.1, 39.1% for the biliary antigen (+) group with no statistically significant difference. The 1, 3 and 5-year overall survival rates were 91.7, 73.8, 66.4% for the biliary antigen (-) group and 68.8, 34.4, 34.4% for the biliary antigen (+) group, with a significantly greater overall survival rate for the biliary antigen negative group (p = 0.045). Poor histopathological differentiation, a high HBsAg positive rate and poor overall survival rate were noted in the biliary antigen positive group and the differences were statistically significant. In conclusion, HCCs with positive biliary antigen, which originates from more primitive cells, is suggested to be more aggressive than HCCs with negative biliary antigen.
Adult↗
Quantification of emotion by nonlinear analysis of the chaotic dynamics of electroencephalograms during perception of 1/f music.
The goal of this study is to quantify and determine the way in which the emotional response to music is reflected in the electrical activities of the brain. When the power spectrum of sequences of musical notes is inversely proportional to the frequency on a log-log plot, we call it 1/f music. According to previous research, most listeners agree that 1/f music is much more pleasing than white (1/f0) or brown (1/f2) music. Based on these studies, we used nonlinear methods to investigate the chaotic dynamics of electroencephalograms (EEGs) elicited by computer-generated 1/f music, white music, and brown music. In this analysis, we used the correlation dimension and the largest Lyapunov exponent as measures of complexity and chaos. We developed a new method that is strikingly faster and more accurate than other algorithms for calculating the nonlinear invariant measures from limited noisy data. At the right temporal lobe, 1/f music elicited lower values of both the correlation dimension and the largest Lyapunov exponent than white or brown music. We observed that brains which feel more pleased show decreased chaotic electrophysiological behavior. By observing that the nonlinear invariant measures for the 1/f distribution of the rhythm with the melody kept constant are lower than those for the 1/f distribution of melody with the rhythm kept constant, we could conclude that the rhythm variations contribute much more to a pleasing response to music than the melody variations do. These results support the assumption that chaos plays an important role in brain function, especially emotion.
Auditory Perception↗
Non-linear dynamical analysis of the EEG in Alzheimer's disease with optimal embedding dimension.
We used non-linear analysis to investigate the dynamical properties underlying the EEG in patients with Alzheimer's disease. We calculated the correlation dimension D2 and the first positive Lyapunov exponent L1. We employed a new method, which was proposed by Kennel et al., to calculate the non-linear invariant measures. That method determined the proper minimum embedding dimension by looking at the behavior of nearest neighbors under a change in the embedding dimension d from d to d + 1. We demonstrated that for limited noisy data, our algorithm was strikingly faster and more accurate than previous ones. Also, we found that, in almost all channels, patients with Alzheimer's disease had significantly lower D2 and L1 values than those for age-approximated healthy controls. These results suggest that brains afflicted by Alzheimer's disease show behaviors which are less chaotic than those of normal healthy brains. In this paper, we show that non-linear analysis can provide a fruitful tool for detecting relative changes, which cannot be detected by conventional linear analysis, in the complexity of brain dynamics. We propose that non-linear dynamical analyses of the EEGs from patients with Alzheimer's disease will be a diagnostic modality in the appropriate clinical setting.
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