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Biomedical subjects

Q Jin

Publications and source records attributed to Q Jin.

At least 55 records · Page 3Linked to original sources
PubMed1998

[Expression of secreted ligand domain of vaccinia growth factor encoded by vaccinia virus strain tian tan in E. coli and insect cells].

Vaccinia virus growth factor (VGF) is encoded by an early gene of vaccinia virus strain TianTan located near the border between the terminal inverted repeats and the internal region of the viral genome as one copy. Its relationship to members of epidermal growth factor superfamily was discovered when computer searches of protein sequences revealed that VGF has strong sequence homology with these growth factors. To further get insight into the biological activity of VGF, we cloned and expressed the secreted ligand domain of VGF (VGFsl) encoded by vaccinia virus strain TianTan in E. coli and insect cells. The results of biological activity test indicated that expressed products is capable of binding to the EGF receptor, and stimulating EGF receptor tyrosin autophosphorylation to a level greater than that of EGF.

Animals↗
PubMed1997

Evidence of spinocerebellar mossy fiber segregation in the juvenile staggerer cerebellum.

Developmental and experimental studies of climbing fiber and mossy fiber connectivity in the cerebellum have suggested that Purkinje cells are the critical organizing elements for connectivity patterns. This hypothesis is supported by evidence that spinocerebellar mossy fiber projections are abnormally diffuse in P25 sg/sg mutant mice in which the differentiation of a reduced number of sg/sg Purkinje cells is blocked due to a cell autonomous defect. However, mossy fiber distribution may be disrupted in sg/sg mutants not because of the Purkinje cell deficits, but because of the death of virtually all granule cells following the 4th postnatal week. To test this hypothesis, we have analyzed the distribution of wheat germ agglutinin-horseradish peroxidase (WGA-HRP)-labeled spinocerebellar mossy fiber terminals in sg/sg mutants at the end of the period of granule cell genesis (postnatal day [P] 12-P13) and before massive granule cell death (P16). Two percent WGA-HRP was injected into the lower thoracic/upper lumbar region of the spinal cord of eight homozygous sg/sg mutants (P12-P16) and five controls (+/sg and +/+). We have found that spinocerebellar mossy fibers segregate into distinct terminal fields in the anterior cerebellar lobules of P12 to P16 sg/sg mutants, although the medial-lateral distribution of spinocerebellar mossy fiber projections is different from controls. The results from this study and previous analysis of sg/sg mutants support the hypothesis that topographic cues are expressed in the early postnatal staggerer mutant, but mossy fiber terminals become disorganized or retract as granule cells die in the older staggerer mutant. J. Comp. Neurol. 378:354-362, 1997.

Animals↗
PubMed1997

[Application of Apo B 3' DNA polymorphisms in forensic science Practice].

Amp-FLP analyses of Apo B 3' VNTR locus in human blood stain, saliva (stain), semen, mixed stain and hair have been carried out. The genotypings have been achieved. The genotypes of Apo B 3' locus can be detected accurately in blood stains kept at room temperature within 15 weeks and at -20 degrees C within two years. In a series of paternity testing on 34 cases, 8 false alleged fathers were excluded; of them, 6 were excluded by Apo B 3' locus alone or by Apo B 3' locus combined with other genetic markers. 3 rape cases were investigated; 2 suspects were excluded.

Apolipoproteins B↗
PubMed1997

[Characteristics of virus growth factor (VGF) encoded by vaccinia virus Tian Tan strain].

Vaccinia virus growth factor (VGF) is encoded by an early gene located near the border between the terminal inverted repeats and the internal unique region of the viral genome. It has been suggested that secreted VGF may serve to stimulate the metabolism of neighboring uninfected cells, thereby increasing the capacity of these cells to support viral replication. In this study, we cloned and sequenced the VGF gene of vaccinia virus strain Tian Tap. The analytical results indicated that VGF of strain Tian Tan possessed the core sequences of Epidermal growth factor superfamily, and more closely related to that of strain WR than to those of other orthopoxvirus strains. Overall deduced amino acid divergence of 4.3% was observed between Tian Tan and WR VGF protein, while divergences ranged from 10% to 20% compared to other orthopoxviruses strains. Most of the amino acid substitutions were found within signal peptide and transmembrane regions, but were not present in secreted ligand domain. It was striking that the amino acid sequence deduced from the ORF TB22L which located within the right terminal region of genome was identical to VGF protein amino acids 67-140, suggesting that ORF TB22L may be derived from the seconed copy of VGF gene of strain Tian Tan.

Intercellular Signaling Peptides and Proteins↗
PubMed1997

[Divergence of VP7 gene and VP4 gene variable regions of G1 rotaviruses isolated from different geographic locations around the world].

Group A rotaviruses are the most important etiologic agents of severe gastroenteritis in children, and as a result, the development of an effective vaccine against severe rotavirus diarrhea is a top public health priority. Previous studies indicated that G1 rotavirus are much more common in most countries around the world and development of G1--specific vaccine may be important in protection against human illness. In this report, we analyzed the VP7 gene and VP4 gene variable regions of 36 G1 rotavirus community strains collected from different geographic locations worldwide. Comparative analysis of the VP7 sequences showed that most of the amino acid substitutions of global strains occurred in and around previously identified epitope regions VR3, VR4, and VR6, suggesting that there are slight antigenic differences among these strains. Growtree phylogram using the VP7 amino acid sequences as an index grouped all strains into three clusters. The VP7 sequence of each cluster possesses distinctive amino acid residues which are peculiar to most members of the same group at a most positions. These data will be essential to achieve a much better understanding of molecular epidemiologic characteristics of G1 rotavirus around the world.

Amino Acid Sequence↗
PubMed1997

[A rapid method for diagnosing alpha-thalassemia-1 of Southeast Asia type].

OBJECTIVE: To explore a rapid method for diagnosing alpha-thalassemia-1 of Southeast Asia type. METHODS: Seventy-six patients were detected by polymerase chain reaction (PCR). RESULTS: Thirty-one patients were diagnosed as alpha-thalassemia-1 of Southeast Asia type. PCR was compared with polyacrylamide gel electropheresis for detecting zeta-globin chain in 56 patients and the correspondance rate was 83.93%. Ten cases of prenatal diagnosis were performed by PCR, and the results showed that one was Hb bart's hydrop fetalis, four were carriers of alpha-thalassemia-1 of Southeast Asia type, and the others were normal fetalis or carrier of alpha-thalassemia-2. CONCLUSION: The PCR method is simple and accurate for diagnosing alpha-thalassemia of Southeast Asia type, and it provides a new approach to the prenatal diagnosis of alpha-thalassemia fetalis and the detection of alpha-globin gene cluster.

Adolescent↗
PubMed1997

[Determination of alkali-earth metal by microwave plasma torch atomic emission spectrometry].

Determination of alkali-earth metal by microwave plasma torch atomic emission spectrometry (MPT-AES) was investigated. Operating conditions the effects of some coexistent elements were examined. Detection limits for Be, Mg, Ca, Sr and Ba are 0.47, 1.4, 0.15, 0.20 and 2.6ng/mL, respectively. Method has been applied to analyse some actual samples with satisfactory results.

English Abstract↗
PubMed1997

TGF-beta 3 inhibits the increased gene expressions of pulmonary surfactant proteins induced by dexamethasone in fetal rat lung in vitro.

OBJECTIVE: To determine the effects of transforming growth factor-beta 3 (TGF-beta 3) on expressions of surfactant proteins (SPs). METHODS: Northern blot hybridization and reverse transcriptase polymerase chain reaction (RT-PCR) were employed to determine the SP-A, SP-B and SP-C mRNA levels of cultured lung explants and type II cells from fetal rat lungs. RESULTS: TGF-beta 3 alone did not affect the expressions of SPs either in explants or in type II cells. However, TGF-beta 3 did inhibit the increase of SP-B, SP-C mRNA levels caused by dexamethasone (100 nmol/L), in a dose-dependent manner. Furthermore, TGF-beta 3 had no direct inhibition on the increase of SP-B, SP-C mRNA induced by dexamethasone in type II cells, but had an indirect inhibitory effect mediated by fibroblasts. CONCLUSION: TGF-beta 3 plays an important inhibitory role in the development of pulmonary surfactant proteins. The present study may provide a possible explanation for the unideal effect of glucocorticoids in the prevention of neonatal respiratory distress syndrome.

Animals↗
PubMed1996

Divergence of VP7 genes of G1 rotaviruses isolated from infants vaccinated with reassortant rhesus rotaviruses.

A large placebo-controlled efficacy trial of the rhesus tetravalent (RRV-TV) and serotype G1 monovalent (RRV-S1) rotavirus vaccines was conducted in 1991-1992 at 24 sites across the United States. Protection was 49% and 54% against all diarrhea but 80% and 69% against very severe gastroenteritis for the two vaccines, respectively. Post-vaccination neutralizing antibody titers to the G1 Wa strain, whose VP7 protein is nearly identical to that of the D strain of rotavirus contained in both vaccines, did not correlate with protection against subsequent illness with G1 strains. This result raised the possibility that in infants who developed post-vaccination neutralizing antibody to Wa, breakthrough (i.e., vaccine failure-the occurrence of rotavirus diarrhea after immunization) may have been due to infection by G1 strains that were sufficiently antigenically distinct from the vaccine strain to evade the neutralizing antibodies elicited by vaccination. To test this hypothesis, we initially compared post-vaccination neutralizing antibody titers of vaccinees against Wa and G1 breakthrough strains using sera from subjects who experienced breakthrough. Post-immunization neutralizing antibody titers to Wa elicited by vaccination were significantly (P < 0.001) greater than to the breakthrough strains subsequently obtained from these subjects. This difference did not, however, correlate with lack of protection since similar differences in titer to Wa and breakthrough strains were found using post-vaccination sera from vaccinees who either experienced asymptomatic rotavirus infections or no infections. To determine the genetic basis for these differences, we compared the VP7 gene sequences of Wa with vaccine strain D, 12 G1 breakthrough strains, and 3 G1 control strains isolated during the same trial from placebo recipients. All breakthrough strains were distinct from Wa and D in antigenically important regions throughout the VP7 protein, but these differences were conserved between breakthrough and placebo strains. Furthermore, a comparative analysis of the deduced amino sequences form VP7 genes of G1 rotaviruses from 12 countries indicated that four distinct lineages have evolved. All breakthrough and control strains from the U.S. vaccine trial were in a lineage different from strain D, the serotype G1 vaccine strain. Although the overall results do not support our original hypothesis that immune selection of antigenically distinct escape mutants led to vaccine breakthrough in subjects with a neutralization response to Wa, it cannot be excluded that breakthrough could be partially due to antigenic differences in the VP7 proteins of currently circulating G1 strains.

Amino Acid Sequence↗
PubMed1996

Isolation of a human rotavirus containing a bovine rotavirus VP4 gene that suppresses replication of other rotaviruses in coinfected cells.

Bovine-human reassortant strains containing ten human rotavirus gene segments and segment 4, encoding VP4, of a bovine rotavirus were isolated from the stool of an infected Bangladeshi infant during cell culture adaptation. Two plaque purified variants of this reassortant, one making very large (429-L4) and the other tiny (429-S4) plaques, were further analyzed. The electropherotypes of these variants were identical except for slight mobility differences in segment 4. The predicted sequence of amino acids (aa) 16-280 in VP4 proteins revealed four differences between variants even in this limited region, so no single difference could be linked to plaque size. The small plaque variant S4 was phenotypically unstable and mutated to a large plaque-former within a single cell culture passage. The predicted sequence of aa 16-280 of a large plaque variant derived from S4 revealed six changes, only one of which was common to that of the L4 strain, thus suggesting that multiple amino acid changes in VP4 may affect plaque size. Although the large plaque variant L4 grew faster and was released from cells more rapidly than S4, its replication and that of other rotaviruses tested (i.e. RRV, NCDV and Wa) was suppressed by S4 in coinfected cells. Using an RRV x S4 reassortant containing only RRV segment 4, it was established that suppression was linked to the S4 VP4 protein. This suppression could not be associated with inhibition of viral adsorption and, therefore, appeared to occur following internalization. Thus, a new property of the rotavirus VP4 protein has been identified in a bovine-human rotavirus reas-sortant.

Amino Acid Sequence↗
PubMed1996

[The expression of pulmonary surfactant proteins B and surfactant protein C in E. coli].

OBJECTIVE: To express biological active surfactant protein B(SP-B) and surfactant protein C(SP-C) combined with synthetic phospholipids to make an ideal exogenous pulmonary surfactant (PS) for the treatment of respiratory distress syndrome (RDS) in future. METHOD: Prokaryote expression vector pIN-II-ompA2-B-C was established with the cDNA fragments of mature human SP-B and SP-C, then the fusion protein of mature SP-B with SP-C was expressed in E. coli BL21 induced by IPTG. The expression of fusion protein in E. coli was confirmed by Western blot anlaysis. The biological activity of the expressed product was measured by Wilhelmy's surface balance (MTP-2). RESULTS: The fusion protein of SP-B with SP-C could be expressed in E. coli BL21, and their molecular weight (Mr) was 20000 on gel electrophoresis, but the amount was small. According to the measurement of Wilhelmy's surface balance (MTP-2), the minimal surface tension of expressed protein in E. coli BL21 could be reduced to 0.004 N/m2 and the area of hysteresis loop was relatively large. CONCLUSIONS: The results of the investigation will be a basis to obtain SP-B and SP-C with gene engineering technology and to create a new way for producing ideal exogenous PS.

Base Sequence↗
PubMed1995

An outbreak of Norwalk virus gastroenteritis associated with eating raw oysters. Implications for maintaining safe oyster beds.

OBJECTIVE: To determine the characteristics and the cause of an outbreak of gastroenteritis associated with eating raw oysters. DESIGN: Survey of groups of persons reporting illness to the health department after eating oysters; survey of convenience sample of oyster harvesters; and tracing of implicated oysters. SETTING: General community. MAIN OUTCOME MEASURES: Relative risk for illness after oyster consumption, source bed of contaminated oysters, presence of antibodies to Norwalk virus in serum, presence of a Norwalk virus in stool by direct electron microscopy and reverse transcription-polymerase chain reaction (RT-PCR), and DNA sequences of RT-PCR products. RESULTS: Seventy (83%) of 84 persons who ate raw oysters became ill vs three (7%) of 43 people who did not eat raw oysters (relative risk, 11.9; 95% confidence interval, 4.0 to 34.2). Eleven (79%) of 14 serum pairs had at least a fourfold increase in antibody to Norwalk virus. All 12 stool samples tested were positive by electron microscopy and/or RT-PCR for Norwalk virus. The RT-PCR products from all seven stool samples tested had identical DNA sequences. Implicated oysters were harvested November 9 through 13, 1993, from a remote oyster bed. Crews from 22 (85%) of 26 oyster harvesting boats working in this area reported routine overboard disposal of sewage. One harvester with a high level of antibodies to Norwalk virus reported having gastroenteritis November 7 through 10 and overboard disposal of feces into the oyster bed. CONCLUSIONS: This outbreak was caused by contamination of oysters in the oyster bed, probably by stool from one or more ill harvesters. Education of oyster harvesters and enforcement of regulations governing waste disposal by oyster harvesting boats might prevent similar outbreaks.

Adolescent↗
PubMed1995

Epidemiologic applications of novel molecular methods to detect and differentiate small round structured viruses (Norwalk-like viruses).

The molecular epidemiology of a large, multistate outbreak of oyster-associated gastroenteritis [Kohn et al. (1995): Journal of the American Medical Association 273:466-471. Dowell et al. (1995): Journal of Infectious Diseases 171:1497-1503.] was examined using new methods to detect small round structured viruses (SRSVs) by reverse transcription-polymerase chain reaction (RT-PCR) and to characterize strains by Southern hybridization and nucleotide sequencing of 81-bp of a PCR product amplified from the RNA polymerase gene. Of 37 stool specimens examined from patients in eight clusters of the multistate outbreak, 32 (86%) gave RT-PCR products specific for SRSVs of P1-A phylogenetic group. Nineteen PCR products from the eight clusters were confirmed to have the identical sequence, indicating that this large outbreak was attributed to a single strain of SRSV. In one of the eight clusters, five (63%) of eight patients had a mixed infection with a second SRSV strain that belonged to P2-B phylogenetic group. Of 12 specimens from patients in five other outbreaks and one sporadic case which occurred at the same time as the multistate outbreak, 10 (83%) gave products specific for SRSVs representing four phylogenetic groups (P1-A, P1-B, P2-A, and P2-B). The sequences of the P1-A products from two outbreaks and that of the P2-B product from another outbreak were identical to the P1-A sequence from the eight clusters and the P2-B sequence from the one cluster of the multistate outbreak, respectively. These results demonstrate the first application of these methods to enhance our understanding of the molecular epidemiology of SRSVs and provide answers of public health interest that could not have been obtained using classical epidemiologic methods alone.

Animals↗
PubMed1995

A multistate outbreak of oyster-associated gastroenteritis: implications for interstate tracing of contaminated shellfish.

In November 1993, clusters of gastroenteritis in six states following oyster consumption were investigated to identify common features, and stool samples were obtained to identify a pathogen. Efforts were made to account for all potentially contaminated oysters using harvest tags and the interstate recall system. Consumption of oysters was associated with illness in 10 clusters; no other food was implicated. A Norwalk-like virus was detected by electron microscopy in 9 of 18 samples and by reverse transcription-polymerase chain reaction in 20 of 26 samples from 6 clusters. Nucleotide sequences of a 123-bp fragment from all specimens were identical, consistent with a common source outbreak. Implicated oysters were harvested from the Louisiana coast between 9 and 12 November. Although some were recalled and destroyed, most oysters harvested from the area during this time remain unaccounted for. Current regulations and commercial practices need to be revised to permit thorough tracing and recall of contaminated oysters and to improve control of future epidemics.

Animals↗