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Biomedical subjects

C C Hong

Publications and source records attributed to C C Hong.

At least 19 recordsLinked to original sources
PubMed1999

Anti-dsDNA autoantibody cross-reacts with the C-terminal hydrophobic cluster region containing phenylalanines in the acidic ribosomal phosphoprotein P1 to exert a cytostatic effect on the cells.

The present study was an attempt to map the epitope in P1 protein which may cross-react with anti-dsDNA. In addition to wild-type P1, the genes of its C-terminal mutants were cloned and expressed. The binding activity of these proteins with anti-dsDNA was determined by Western blot and ELISA. The P1 mutants with complete deletion of the acidic charge and hydrophobic clusters, deletion of the hydrophobic cluster, or replacement of the phenylanlanines with alanine in the hydrophobic cluster lost the binding activity. Moreover, P1 mutants with mutation at the serine phosphorylation sites (positions 102 and 105) retained their binding activities with anti-dsDNA. However, those with mutation at the serine phosphorylation sites and without the hydrophobic cluster lost their binding activities. These findings suggest that phenylalanines in the C-terminal hydrophobic cluster region of ribosomal P proteins are essential to their cross-reactivity with anti-dsDNA.

Amino Acid Sequence↗
PubMed1999

Signal transduction by a protease cascade.

The dorsoventral axis of the Drosophila embryo is determined by a spatial cue generated by ovarian somatic cells. This cue is communicated to the embryo through an extracellular serine protease cascade active only on the ventral side of the embryo. Studies of the proteases and somatically expressed proteins involved in this signalling process suggest a working model for how the protease cascade is locally activated hours after the ovarian somatic cells have degenerated.

Animals↗
PubMed1997

Abundance, parity, and Japanese encephalitis virus infection of mosquitoes (Diptera:Culicidae) in Sepang District, Malaysia.

A 2-yr study of Japanese encephalitis (JE) virus in Sepang District, Selangor, Malaysia, was carried out to identify the mosquito vectors and to determine their seasonal abundance, parity, and infection rates. In total, 81,889 mosquitoes belonging to 9 genera and > 50 species were identified from CDC trap collections augmented with dry ice during 1992 and 1993. Culex tritaeniorhynchus Giles and Culex gelidus Giles were the most abundant species, and both increased in numbers with increases in rainfall. Overall, 45 JE virus isolations were made from 7 species-Cx. tritaeniorhynchus (24), Cx. gelidus (12), Culex fuscocephala Theobald (2), Aedes butleri Theobald (4), Culex quinquefasciatus Say (1), Aedes lineatopennis Ludlow (1), and Aedes (Cancraedes) sp. (1). Based on elevated abundance and JE infection rates, Cx. tritaeniorhynchus appears to be the most important vector of JE virus in Sepang.

Aedes↗
PubMed1997

REM sleep eye movement counts correlate with visual imagery in dreaming: a pilot study.

Based on the findings of our previously published positron emission tomography study, we proposed that recorded eye movements during REM sleep are visually targeted saccades. In the present study, we examined the correlation between the number of eye movements in REM sleep (EM) and visual imagery in dreaming (V) and provided further support for our proposal. All the observations (N = 11) were made with one individual to eliminate interindividual variation and were made during the second REM sleep period to control for a time-of-night effect. V, with or without dream report length partialled out, was strongly associated with EM only in the 1-min interval immediately preceding awakening. The time course of the association suggests that the strong EM-V association reflects a phasic, localized activation of the eye-movement-control system in association with REM sleep eye movements.

Adult↗
PubMed1997

Assessment of the ability of propoxur, methomyl, and aldicarb, three carbamate insecticides, to induce micronuclei in vitro in cultured Chinese hamster ovary cells and in vivo in BALB/c mice.

Three carbamate insecticides (propoxur, methomyl, and aldicarb) were evaluated for their ability to induce micronuclei (MN) in vitro using cultured Chinese hamster ovary (CHO) cells, and in vivo in mouse bone marrow erythrocytes. In vitro, all three insecticides induced a significant increase in micronucleated binucleate cells, which was generally both dose and sample time dependent. The in vivo studies involved treating male BALB/c mice by different routes, either once or on 3 consecutive days, followed by multiple or single sampling. Treatment by intraperitoneal injection or oral gavage induced a significant increase in micronucleated reticulocytes (MNRETs) in peripheral blood. For all three chemicals, the MN response depended on sample time and the number of treatments, while for aldicarb, the response depended also on the route of exposure. These positive results demonstrate that propoxur, methomyl, and aldicarb are capable of inducing structural and/or numerical chromosomal aberrations in mammalian cells either in vitro or in vivo. Furthermore, based on the results obtained, on optimal in vivo MN protocol for carbamate insecticides is a single treatment followed by blood sampling at 24 and 48 hr after treatment.

Aldicarb↗
PubMed1996

Effects of zolpidem on local cerebral glucose metabolism during non-REM sleep in normal volunteers: a positron emission tomography study.

Using positron emission tomography with fluorodeoxyglucose (18FDG or FDG), we compared the effects of zolpidem (10 mg), an imidazopyridine hypnotic, which is relatively selective for the BZ1 or omega receptor and placebo on cerebral glucose metabolism during the first non-REM sleep period of 12 young normal volunteers. Plasma zolpidem pharmacokinetics varied considerably among subjects, and plasma concentrations were lower than usually reported. In general, the effects of zolpidem on local cerebral glucose metabolism varied directly with plasma concentrations of zolpidem. Zolpidem induced changes in local cerebral glucose metabolism were unevenly distributed throughout the brain and were greater in subcortical areas than lateral cortical areas. Significant negative correlations were found between change in local absolute glucose metabolic rate (calculated by subtracting individual data on placebo nights from that on zolpidem nights) and plasma concentration of zolpidem for the following areas: medial frontal cortex, cingulate gyrus, putamen, thalamus, and hippocampus. The effects of zolpidem on local cerebral glucose metabolism were partially but not closely related to the reported density of BZ1 receptors.

Adult↗
PubMed1996

The maternal nudel protein of Drosophila has two distinct roles important for embryogenesis.

The nudel gene is maternally required to define dorsoventral polarity of the Drosophila embryo. It encodes an unusual mosaic protein with a protease domain that may trigger the protease cascade required for ventral development. We describe phenotypic and molecular analyses of nudel mutations that provide further insight into nudel protein function. Surprisingly, nudel mutations primarily cause either dorsalized embryos in which dorsal cell fates are expanded over ventral and lateral cell fates or fragile eggs that fail to develop beyond early embryonic stages. The nudel protein is therefore required not only for embryonic dorsoventral polarity but also for structural integrity of the egg. Complementation and antagonistic interactions between nudel alleles suggest that the nudel protein is functionally modular and that protein-protein interactions are important for nudel protein function. Three nudel mutations that produce dorsalized embryos map to the protease domain of nudel, suggesting that this domain is specifically required for defining embryonic dorsoventral polarity. Finally, certain combinations of nudel alleles simultaneously produce completely dorsalized and normal embryos yet very few embryos of intermediate mutant phenotypes. The unusual biphasic distribution of phenotypes may indicate that nudel activity above a threshold is required to generate embryonic dorsoventral polarity.

Alleles↗
PubMed1996

Language in dreaming and regional EEG alpha power.

In an intensive single-subject design, electroencephalographic (EEG) alpha power and receptive and expressive language in dreaming were studied in 12 dreams during rapid eye movement (REM) sleep on 12 separate nights. Bilateral EEG was recorded continuously from 21 sites and digitized. We used the Fast Fourier transformation (FFT) for power spectral analysis to measure EEG power in the alpha frequency range (8-12 Hz) at each of the EEG sites. The subject was awakened after about 14 minutes into the second REM period, and dream reports were collected. We scored the dream reports for expressive and receptive language. The lower the alpha power on the left sides of those homologous pairs that roughly correspond to Broca's (C3) or Wernicke's area (P3), the more expressive or receptive language in dream reports. The largest difference between the correlation of the left and that of the right homologous pair of regions was found in the central (C3, C4) area for expressive language and in the parietal (P3, P4) area for receptive language. Our finding suggests lateralized and localized cortical activation in relation to language in dreaming.

Adult↗
PubMed1996

Spontaneous pulmonary squamous cell carcinoma in an aging CD rat.

Naturally occurring squamous cell carcinomas of lung of laboratory rodents are rare, and few cases have been reported and illustrated. A solid peripheral lung mass was observed grossly in a untreated 573-day-old male Sprague Dawley CD (Crl:CD [SD] BR) rat. Microscopically, the mass was composed of neoplastic squamous epithelial cells arranged in nests, cords, nodules, or solid sheets. Epithelial pearls were present. The mitotic index was high, and intercellular bridging (prickles) was noted. In some areas, neoplastic cells rimmed large cystic areas containing neutrophils, cell debris, and laminated keratin masses. Neoplastic cells had both expansive and invasive growth with entrapment of bronchioles and marked fibroplasia.

Age Factors↗
PubMed1996

Cross-sectional serosurvey for Japanese encephalitis specific antibody from animal sera in Malaysia 1993.

Serum specimens were collected from 6 species of animals living in 9 states of Malaysia including Sabah, North Borneo in 1993. Antibodies against Japanese encephalitis (JE) virus in these sera were detected by means of hemagglutination-inhibition (HI) and neutralization (NT) tests. By HI test, 702 of 2,152 (32.6%) sera showed positive results. Higher positive rates were obtained by the NT test, in which 1,787 of 1,927 (92.7%) sera had antibodies against JE virus. All serum specimens with positive HI were confirmed as positive by the NT. Swine sera showed especially higher rates of antibody positive and higher antibody titers compared with other animals. These results suggest that JE infections are widely distributed among many animals of Malaysia, and pig is the most susceptible amplifier host for JE virus.

Animal Diseases↗
PubMed1995

An unusual mosaic protein with a protease domain, encoded by the nudel gene, is involved in defining embryonic dorsoventral polarity in Drosophila.

Dorsoventral polarity of the Drosophila embryo is induced by a ventral extracellular signal, which is produced by a locally activated protease cascade within the extraembryonic perivitelline compartment. Local activation of the protease cascade depends on a positional cue that is laid down during oogenesis outside the oocyte. Here we present evidence that the nudel gene encodes an essential component of this cue. The nudel gene, which is expressed in follicle cells covering the oocyte, encodes an unusual mosaic protein resembling an extracellular matrix protein with a central serine protease domain. Our findings suggest that embryonic dorsoventral polarity is defined by a positional cue that requires the nudel protein to anchor and to trigger the protease cascade producing the polarity-inducing signal.

Amino Acid Sequence↗
PubMed1995

Localized and lateralized cerebral glucose metabolism associated with eye movements during REM sleep and wakefulness: a positron emission tomography (PET) study.

In order to study the neural substrate for eye movements during rapid eye movement (REM) sleep, we analyzed the positron emission tomography (18Fluorodeoxyglucose positron emission tomography) scan data obtained from normal subjects. Eye movement data were available on nine subjects studied during nighttime REM sleep and six control subjects studied during waking as they periodically moved their eyes. The number of eye movements during REM sleep was positively correlated with glucose metabolic rate in the areas corresponding to (a) the saccadic eye movement system (frontal eye field and dorsolateral prefrontal cortex, statistically significant only on the right side), (b) the midline attentional system (cingulate and medial frontal cortex, precuneus) and (c) the parietal visual spatial attentional system (bilateral superior parietal lobules, right inferior parietal lobule); and negatively correlated with relative metabolic rate in the left inferior parietal lobule. Positive correlations between waking eye movements and metabolic rate were observed in the same areas except inferior parietal lobule. Our results show that the same cortical areas are involved in eye movements in both REM sleep and wakefulness and suggest that REM sleep eye movements are saccadic scans of targets in the dream scene. Our data also suggest right hemispheric specialization in saccadic eye movement control and reciprocal inhibition in the contralateral homologous area during higher cortical functioning.

Attention↗
PubMed1995

Nasal adenocarcinoma with myoepithelial component in a CD-1 mouse.

Spontaneous nasal tumors are rare in mice, and only one adenocarcinoma and two more primary neoplasms of the nose have been observed in our files of long-term feeding studies, which are composed of 3,419 male and 3,521 female CD-1 (Crl:CD-1 (ICR)BR) mice. This adenocarcinoma was a 1-cm-diameter mass observed grossly in the right nasal cavity of a 454-day-old, male CD-1 mouse from a treated group in a bioassay study conducted with 340 males and 340 females. The neoplastic epithelial cells affected the normal nasal architecture on the right side of the nose. Roughly, tumor neoplastic cells of the outer, lateral portion occurred as cuboidal to low columnar cells with basilarily located nuclei and eosinophilic cytoplasm. These cells were arranged in cylindrical profiles and frequently entrapped acini of the glands of the maxillary sinus. Neoplastic epithelial cells of the inner, medial portion appeared as serous acinar or ductular structures circumscribed by multiple lagers of myoepithelial-like cells. Staining failed to demonstrate mucous secretion. The site of origin of this neoplasm appeared to be the serous glands of the maxillary sinus. The adenocarcinoma was believed to be spontaneous.

Adenocarcinoma↗
PubMed1995

Regional and maturation-associated expression of endothelin 2 in rat gastrointestinal tract.

Endothelin 2 (ET2), also referred to as vasoactive intestinal contractor peptide, is a member of a family of vasoactive peptides. ET2 is a potent constrictor of intestinal smooth muscle, and the mRNA that encodes it has been detected in murine intestinal extracts. To further investigate the potential physiological roles of ET2, we characterized the cellular distribution of ET2 gene expression in adult rat gastrointestinal tract. Using an RNAse protection assay, an overall proximal to distal gradient of increasing ET2 gene expression was observed from stomach to colon. In situ hybridization studies confirmed this finding and demonstrated ET2 mRNA localized in lamina propria stromal cells. Moreover, ET2 gene expression in stromal cells increased from crypt to villous tip. The results demonstrate that ET2 is produced by stromal cells in villi throughout the intestine. Increased ET2 gene expression at the villous tip is associated with more mature overlying epithelial cells, suggesting a possible role for this vasoactive peptide in intestinal epithelial differentiation or secretory activity.

Animals↗
PubMed1995

Simultaneous identification and determination of residual penicillins by use of high-performance liquid chromatography with spectrophotometric or fluorometric detectors.

Using 7 penicillins (amoxicillin, ampicillin, methicillin, penicillin G, oxacillin, cloxacillin, and dicloxacillin), simultaneous and direct determination of residual penicillins in biological samples was carried out by use of bioassay and high-performance liquid chromatography with spectrophotometric or fluorometric detectors. By use of assay medium seeded with penicillin-sensitive Micrococcus luteus (ATCC No. 9341) as a test organism, we were able to detect penicillins even at low concentrations. All penicillins treated with 10 U of penicillinase/ml did not produce inhibition zones by disk testing, even at a concentration of 100 micrograms of penicillin/ml/assay plate. Using a mobile phase of acetonitrile:methanol: 0.01M KH2PO4 (19:11:70, v/v/v; pH, 7.1), standard solutions of the penicillins were separated from each other by use of high-performance liquid chromatography analysis, producing symmetric peaks without tailing, each of which had a characteristic retention time. Simultaneous detection of residual penicillins in bovine serum, kidneys, and liver, for the 5 penicillins for which analysis was possible by use of the UV method, yielded recovery rates from 71.4 to 102.3%; for the 2 amino-penicillins, amoxicillin and ampicillin, which could only be detected by use of the fluorometric method, recovery rate ranged from 72.9 to 103%.

Animals↗
PubMed1995

Epizootic of low-virulence hepatotropic murine hepatitis virus in a nude mice breeding colony in Taiwan.

A natural outbreak of mouse hepatitis virus infection developed in a breeding colony of nude mice in Taiwan. The outbreak was unique in that morbidity was high in both adult and suckling mice, but only sucklings died. In contrast, all suckling heterozygous (nu/+) mice survived, and no lesions were found in adult female heterozygous (nu/+) mice. Adult male nude mice had chronic, active, necrotizing hepatitis with syncytial giant cells, but no lesions were detected in other tissues. Immunohistochemistry with anti-A59 and anti-JHM serum revealed mouse hepatitis virus antigen in the liver of infected adult and suckling nude mice, although less intensively in the kidney of adult nude mice. Suckling BALB/c mice inoculated with filtrates of the liver of adult nude mice developed hepatitis similar to that in the naturally infected nude mice. Virus was isolated by inoculating cell-free liver filtrate from infected adult nude mice onto 3T3 cells. Electron microscopy of purified virus revealed 100-nm-diameter enveloped particles with characteristic petal-shaped surface projections. We conclude that the outbreak was caused by a weakly virulent, highly hepatotropic murine hepatitis virus.

Animals↗
PubMed1994

Transfusion-associated respiratory distress in Taiwan.

Transfusion-associated respiratory distress occurred more often in the past in Taiwan but recently only very rarely. From the results of our studies it would appear that the former cases did not represent immune reactions involving red blood cells, serum proteins (especially IgA), HLA or granulocyte-specific antigens. Other causes, such as improper handling of the blood units may have been involved, but further study is also needed to investigate the possibility of the role of cytokine release from leukocytes or other factors. In addition, it appears that both plasma and serum obtained by recalcification of plasma may cause false-positive reactions in the granulocyte microagglutination test.

Adolescent↗