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T Hung

Publications and source records attributed to T Hung.

At least 37 records · Page 2Linked to original sources
PubMed1993

Gamma/delta T-cell receptor expression in the jejunal epithelium of patients with dermatitis herpetiformis and coeliac disease.

The density of jejunal intra-epithelial T cells expressing the gamma/delta form of the T-cell receptor is known to be increased in coeliac disease, the significance of which remains a mystery. The expression of the gamma/delta T-cell receptor in the jejunum of patients with dermatitis herpetiformis, coeliac disease, treated and untreated, and controls were studied. Expression of the gamma/delta T-cell receptor was significantly increased in patients with dermatitis hepetiformis (P < 0.0005) and in both untreated (P < 0.0005) and treated coeliac patients (P < 0.05) compared with controls. There were significant correlations between the indices of enteropathy, enterocyte height (P < 0.005) and villous height/crypt depth ratio (P < 0.0001), and expression of the gamma/delta T-cell receptor in the jejunum of all the patients. This argues against the hypothesis that gamma/delta T-cells have a fundamental role in the aetiology of gluten-sensitive enteropathy. It suggests that gamma/delta T cells may be involved in the effector arm of the mucosal immune response to cereal peptides in susceptible individuals.

Adult↗
PubMed1993

Na(+)-K(+)-2Cl- cotransport and Cl- secretion evoked by heat-stable enterotoxin is microfilament dependent in T84 cells.

We previously reported that adenosine 3',5'-cyclic monophosphate-mediated stimulation of Cl- secretion in the human intestinal epithelial cell line T84 is accompanied by significant remodeling of F-actin and that both the secretory and cytoskeletal responses may be inhibited by phalloidin derivatives, agents that polymerize actin and prevent dynamic reorganization of microfilaments. In contrast, the carbachol-elicited Cl- secretory response (Ca2+ mediated) was not attenuated by phalloidin (J. Clin. Invest. 87: 1903-1909, 1991). In the present study, we examine the effect of phalloidin on the Cl- secretory response elicited by the heat-stable enterotoxin of Escherichia coli (STa), which induces elevations in intracellular guanosine 3',5'-cyclic monophosphate. We find that apical administration of 1 microM STa results in a regionally restricted redistribution of F-actin confined to the basal pole of the cells. In monolayers pretreated with phalloidin, the Cl- secretory response to STa was inhibited by > 60%. Sequential treatment of phalloidin-loaded monolayers with STa followed by carbachol resulted in a synergistic secretory response that was not different from control (unloaded) monolayers. Examination of efflux/uptake through specific membrane transport pathways involved in STa-stimulated Cl- secretion indicated normal activation of apical Cl- and basolateral K+ channels under phalloidin-loaded conditions. The ability of STa-treated monolayers to pump Na+ in an absorptive direction was also unaffected by phalloidin. der phalloidin-loaded conditions, STa-stimulated Na(+)-K(+)-2Cl- cotransporter activity was reduced by approximately 60%, sufficient to account for the observed inhibition of net Cl- secretory response.(ABSTRACT TRUNCATED AT 250 WORDS)

Actin Cytoskeleton↗
PubMed1992

Coding assignments of the genome of adult diarrhea rotavirus.

Adult diarrhea rotavirus (ADRV) has caused epidemics of diarrhea in China since 1982 and remains the only group B rotavirus associated with widespread disease in humans. We recently characterized the proteins of ADRV and have now proceeded to identify the gene segments encoding each protein. Viral RNA transcripts were synthesized in vitro with the endogenous viral RNA polymerase and separated by electrophoresis in agarose. The individual transcripts were translated in a cell-free system using nuclease-treated rabbit reticulocyte lysates. The translation products were compared with polypeptides found in purified virus and were characterized by SDS-PAGE, immunoprecipitation, and Western blot analysis using antisera to double- and single-shelled virions, virus cores, and monoclonal antibodies. Furthermore, individual RNA transcripts were hybridized to total dsRNA to determine their genomic origin. Based on this analysis, the core polypeptides VP1, VP2 and VP3 are encoded by segments 1, 2, and 3, respectively. The main polypeptides in the inner capsid, VP6, and the outer capsid, VP4 and VP7, are encoded by segments 6, 4, and 8 respectively. Segments 5, 7, and 9 code for 60, 45, and 30 kDa nonstructural polypeptides. Two other nonstructural polypeptides (24 and 25 kDa) are derived from gene segment 11. Gene segment 10 codes for a 26 kDa polypeptide that is precipitated with serum to ADRV and may be a structural protein VP9. With this exception, gene coding assignments of ADRV are comparable to those of the group A rotaviruses. Our results have clear implications for further work in cloning, sequencing, and expression genes of ADRV and can provide direction towards understanding the origin and the evolution of this virus.

Animals↗
PubMed1992

Identification of Hantaan virus-related structures in kidneys of cadavers with haemorrhagic fever with renal syndrome.

The etiologic agent of haemorrhagic fever with renal syndrome (HFRS), Hantaan virus, was first isolated in 1976. Since then numerous Hantaan-like viruses have been isolated and five serotypes of Hantavirus have been recognized. Serological studies indicate that these viruses are globally distributed, with each serotype occurring in specific areas. Hantaan virus has been intensively studied antigenically, biochemically, and genetically. However there is still a paucity of information on the pathogenesis of Hantaan virus in the human host. In this paper, we report the detection by thin section immune electron microscopy of the occurrence of numerous dense precipitates, typical inclusion bodies, a surface antigen layer, as well as Hantaan virion-like structures in the kidneys of patients that died during the acute phase of HFRS. These findings may shed some light on understanding the pathogenesis of HFRS in target organs most affected by the disease, such as the kidneys.

Adult↗
PubMed1990

Identification of the gene encoding the group B rotavirus VP7 equivalent: primary characterization of the ADRV segment 9 RNA.

Gene segment 9 of the adult diarrheal rotavirus, ADRV, has been cloned, and the full-length gene 9 cDNA has been sequenced. Sequences at the 5' and 3' termini of the gene 9 double-stranded RNA were confirmed by direct RNA sequencing. The ninth RNA segment is 814 bases in length with a single open reading frame beginning at base 10 and terminating at base 757. The encoded polypeptide contains 249 amino acids with a calculated molecular weight of 28.5 kDa. The protein contains three potential N-linked glycosylation sites and a hydrophobic signal-like sequence at its amino terminus. A search of the NBRF protein data base with the encoded polypeptide revealed extensive similarities with VP7 proteins from a number of group A rotaviruses. Direct comparisons of the ADRV gene 9 polypeptide and the group A rotavirus VP7 demonstrate that the two proteins share 78% amino acid similarity and 28% identity as well as predicted secondary structure similarities. These findings suggest that the ADRV gene segment 9 encodes the VP7 polypeptide equivalent of group A rotaviruses.

Amino Acid Sequence↗
PubMed1990

cDNA cloning of each genomic segment of the group B rotavirus ADRV: molecular characterization of the 11th RNA segment.

The group B noncultivatable rotavirus, ADRV, was purified from infected stool specimens. Double-stranded RNA was extracted, polyadenylated, reverse transcribed into cDNA, and cloned into plasmid vector pAT153. Each cDNA clone hybridized to a single ADRV RNA segment and cDNA clones of each genomic RNA segment were identified. Sequencing of genomic RNA and a full-length cDNA clone (AD63) determined that ADRV RNA segment 11 is 631 bases in length and contains a single open reading frame of 170 amino acids with a calculated molecular weight of 19.9 kDa and a pl of 6.2. The RNA 5'- and 3'-termini contain untranslated regions of 58 and 63 bases, respectively, and are complementary to each other. A comparison of encoded ADRV gene 11 amino acids with the NS26 protein of group A rotaviruses demonstrates a distant similarity between the two proteins. Further analysis and use of these ADRV clones should aid in determining the gene coding assignments for group B proteins as well as for diagnostic detection of group B or ADRV-specific nucleic acids in specimens.

Amino Acid Sequence↗
PubMed1989

Investigation of an outbreak of adult diarrhea rotavirus in China.

In 1987 an epidemic of diarrhea associated with adult diarrhea rotavirus (ADRV) occurred in Qinhuangdao City, China, affecting more than 200 persons and causing 2 deaths. The outbreak was introduced by a person returning from an epidemic area and was spread initially to his family members and subsequently to the entire community. Adults were at greater risk of diarrhea than children 0-4 y of age and, the duration of illness increased significantly with increasing age. ADRV was identified by ELISA and electron microscopy. The electropherotypes of all positive specimens were identical, consistent with the single point-source introduction of the virus. Seroconversion was detected in 6 of 7 ill persons with a blocking ELISA. Both asymptomatic infection and person-to-person spread identified in this epidemic suggest that current emphasis on preventing waterborne transmission may not control the introduction of ADRV into new areas. The predisposition of adults for more severe disease with ADRV is similar to the pattern observed with other enteric viruses such as the Norwalk agent and hepatitis A.

Adolescent↗
PubMed1989

Seroepidemiology of adult diarrhea rotavirus in China, 1977 to 1987.

In 1982, large outbreaks of diarrhea that were caused by group B adult diarrhea rotavirus (ADRV) occurred throughout the People's Republic of China. Until 1982, group B rotavirus had never been associated with disease in humans. To determine whether ADRV was a new virus introduced in 1982 or had been present before that time, we examined antibody titers of ADRV in gamma globulin (pooled immunoglobulin) pools that were prepared during 1977 to 1987 in four cities in the People's Republic of China (Shanghai, Lanzhou, Wuhan, and Chandu). ADRV antibodies were assayed by using a blocking enzyme-linked immunosorbent assay. Antibodies were present in most Chinese gamma globulins tested, including those collected in Shanghai before the 1982 epidemic, and absent from American reference pools. The highest titers of antibody to ADRV (3,200) were found in gamma globulins collected in 1983 in Shanghai just after the epidemic, and these were fourfold higher than titers present in the preceding years. The quality of the gamma globulins stored for up to 12 years was tested by measuring levels of immunoglobulin G to group A rotavirus; these were equally high in gamma globulin pools prepared in the United States and in all samples from the People's Republic of China. Serum samples from patients from an outbreak of ADRV had elevated titers to ADRV 3 and 16 months after the onset of symptoms. These findings, as well as other epidemiologic findings on ADRV, suggest that the organism is an important and continuing cause of diarrhea in the People's Republic of China, was present before the first epidemic in 1982, and represents a risk to surrounding populations in Asia.

Adult↗
PubMed1989

Rapid diagnosis of adult diarrhea rotavirus (ADRV): detection of viral antigens in faecal samples using staphylococcal co-agglutination test.

Staphylococcus aureus Cowan I rich in protein A when sensitized with guinea pig antiserum to adult diarrhea rotavirus (ADRV) at 1:16 gave a strong co-agglutination with ADRV-positive faecal samples as previously confirmed by electron microscopy (EM) and enzyme-linked immunosorbent assay (ELISA). The bacteria sensitized with normal guinea pig serum did not give any co-agglutination. Blocking tests using rabbit ADRV-specific antiserum for the treatment of twelve ADRV-positive samples abolished the reaction. All the fifty ELISA-confirmed ADRV-positive faecal samples gave positive co-agglutination, whereas all the forty-eight ELISA-negative faecal samples from healthy subjects gave negative results. The test has been proved to be rapid, simple, specific, and economic, useful for rapid diagnosis even in remote areas, so that the ADRV infection can definitely be differentiated from some of acute bacterial diarrheas.

Agglutination Tests↗
PubMed1987

Seroepidemiology and molecular epidemiology of the Chinese rotavirus.

The Chinese rotavirus which causes epidemics of diarrhoea in adult humans was isolated in 1983. This virus, designated adult diarrhoea rotavirus (ADRV), resembles typical rotaviruses morphologically and has a genome made up of 11 discrete segments of double-stranded RNA. Because the Chinese rotavirus has a unique RNA pattern on polyacrylamide gel electrophoresis and is antigenically distinct from group A rotaviruses, it is tentatively included in group B. Infection with ADRV or ADRV-related viruses (as shown by serological study) is detected in human populations as widespread as mainland China, Hong Kong, Australia, the United States and Canada, and in some domestic animals. RNA co-electrophoresis has shown homology of isolates from 12 different outbreaks (with some minor variations at segments 10, 11, 3 and 5). cDNA probes and monoclonal antibodies have been prepared to improve the detection and further characterization of the virus.

Adult↗
PubMed1987

Effects of two negative staining methods on the Chinese atypical rotavirus.

The Chinese atypical (Group B) rotavirus, previously called the adult diarrhoea rotavirus (ADRV), was examined by transmission electron microscopy using either uranyl acetate or potassium phosphotungstate (PTA) as negative stains. Complete rotavirus particles were seen using uranyl acetate which were indistinguishable morphologically from typical rotaviruses. In the same preparations virus particles with differing degrees of degradation were seen after staining with PTA. This effect was not related to pH of the PTA and could be prevented by fixation of the specimen by 0.1 per cent glutaraldehyde. It is concluded that the use of PTA can give rise to falsely negative results for specimens containing this virus.

Glutaral↗
PubMed1987

Myasthenia gravis: population differences in disease expression and acetylcholine receptor antibody titers between Chinese and Caucasians.

Clinical features and anti-acetylcholine receptor (AChR) titers were compared in Chinese (n = 258) and Caucasian (n = 258) myasthenia gravis populations. The former had more early onset and ocular cases, lacked the Caucasian late onset peak, and had fewer severe cases. The distribution of anti-AChR titers was broadly similar in the two populations, and their sera reacted equally well with AChR in both races. The significantly lower (chi 2 = 14.6; p less than 0.001) median anti-AChR titer in the Chinese population can be accounted for by the higher frequency of ocular cases and lower frequency of moderate or severely affected cases.

Adolescent↗
PubMed1986

Genome analysis of human rotaviruses by oligonucleotide mapping of isolated RNA segments.

The genomes of adult diarrhoea rotaviruses isolated in different parts of China during winter outbreaks in 1983 and 1984 were compared by segmental oligonucleotide (ON) mapping. The RNA profiles of most of the isolates were indistinguishable but it was found that some corresponding RNA segments had identical or very closely related ON maps whereas others differed considerably. This finding can be taken to suggest that the strains compared may be genetically related by a natural reassortment event. The genomes of cocirculating group A rotaviruses isolated in Scotland during winter outbreaks in 1981/82 were also compared. The ON maps of corresponding RNA segment differed extensively irrespective of whether or not the segments comigrated on gels.

Adult↗
PubMed1985

Morphology and morphogenesis of viruses of hemorrhagic fever with renal syndrome (HFRS). I. Some peculiar aspects of the morphogenesis of various strains of HFRS virus.

The morphology and morphogenesis of viruses of hemorrhagic fever with renal syndrome (HFRS) were studied by thin-section electron microscopy. Ten strains of HFRS virus isolated in China and one strain isolated in Korea were compared. The virions varied in size as well as in the shape and character of their inner components. Both intracellular and extracellular ribosome-like, electron-dense, virus-associated granules were seen. A viral antigen layer was often visualized on the surface of HFRS virus-infected cells, as confirmed by immune electron microscopy. Aberrant tailed particles and elongated rod-like particles were seen infrequently. The morphogenesis of HFRS viruses appears to be more complex than that of other members of the family Bunyaviridae. The prototype Hantaan virus shares a common morphology and morphogenesis with the other HFRS viruses studied.

Animals↗