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Biomedical subjects

R Jiang

Publications and source records attributed to R Jiang.

At least 55 records · Page 3Linked to original sources
PubMed1999

[Antagonistic effects of metallothionein on genetic damage caused by gamma-rays and mitomycin C].

OBJECTIVE: To study the antagonistic effects of metallothionein (Zn-MT)on genetic damage caused by gamma-rays and mitomycin C (MMC) in the liver of rabbits. METHODS: Micronucleus test and DNA strand breaks were determined in vitro and in vivo with single-cell gel electrophoresis assay to observe the effects of Zn-MT on the micronucleus formation and cleavage of DNA chain before and after gamma-rays radiation and MMC treatment. RESULTS: A dose of 664 microg/kg of Zn-MT could inhibit micronucleus formation in the bone marrow of the mice induced by 5 Gy gamma-rays radiation (P < 0.05). Concentrations of 10 and 50 microg/ml Zn-MT could antagonize the increase in bimicronucleus frequency in g12 cells induced by 1 and 3 Gy gamma-rays radiation and 0.3 microg/ml MMC treatment (P < 0.05 or P < 0.01). A dose of 50 microg/ml Zn-MT could reduce the DNA single strand breaks caused by 1 Gy gamma-rays radiation, but without statistical significance (P > 0.05). CONCLUSION: Zn-MT could antagonize the genetic damage to certain extent in the liver of the rabbits caused by gamma-rays radiation and MMC treatment.

Animals↗
PubMed1999

[Study on the posterior vitreous detachment in patients with high myopia].

OBJECTIVE: To access the development of posterior vitreous detachment(PVD) related to age, axial length of the eye, vitreous changes as well as the myopic chorioretinal manifestation in patients with high myopia. METHODS: The vitreous status of 61 consecutive patients with high myopia(> or = -8.0 D and axial length > or = 26.0 mm) 110 eyes and 68 controls (< or = -3.0 D) 119 eyes were examined with biomicroscopic slit lamp and B-scan ultrasound. The myopic chorioretinal changes at the posterior pole were examined by indirect ophthalmoscope. The axial length of the eye was measured by A-scan ultrasound. The incidence of PVD was evaluated by Chi-square test. RESULTS: The incidence of PVD in patients with high myopia increased with age. Its overall incidence was significantly higher than that in the controls (78.2% vs 31.1%, P < 0.001). In addition, the onset of PVD in patients with high myopia occurred much earlier in age than that in the control group. Axial length was an important factor responsible for the development of PVD in patients with high myopia. The incidence of PVD and age were highly correlated (r = 0.9997, P < 0.05). Retinal detachment occurred in 5 eyes in the patients with high myopia. CONCLUSIONS: The results in the present study suggested that the incidence of PVD in patients with high myopia, increased with axial length of the eye and age. Vitreous changes are characteristic findings associated with high myopia, which was also involved in the development of PVD.

Adult↗
PubMed1998

Genomic organization, expression and chromosomal localization of the mouse Slug (Slugh) gene.

The Slug gene encodes a zinc finger protein implicated in the generation and migration of neural crest cells in several vertebrate species. Here we describe the genomic organization and chromosomal localization of the mouse Slug (Slugh) gene. The mouse Slug gene consists of three exons spanning approx. 4 kb. Northern blot analysis of RNA isolated from several tissues of adult mice revealed the presence of a single 2.1 kb transcript. The chromosomal location of mouse Slug was determined by interspecific backcross analysis. The mapping results indicated that Slugh is located in the proximal region of mouse chromosome 16.

Animals↗
PubMed1998

The Slug gene is not essential for mesoderm or neural crest development in mice.

The Slug gene encodes a zinc finger protein, homologous to the product of the Drosophila Snail gene, that is implicated in the generation and migration of both mesoderm and neural crest cells in several vertebrate species. We describe here the cloning and genetic analysis of the mouse Slug (Slugh) gene. Slugh encodes a 269-amino-acid protein the shares 92% amino acid identity with the product of the chicken Slug gene. We have characterized Slugh gene expression during early mouse embryogenesis by whole mount in situ hybridization of Slugh mRNA and through detection of beta-galactosidase expression from an in-frame SlughIacZ allele generated through homologous recombination. Slugh expression is first detected in extraembryonic mesoderm and is later detected in many mesodermal subsets, although it is not detected in the primitive streak. In contrast to many other vertebrates, the mouse Slug gene is not expressed in premigratory neural crest cells but is expressed in migratory neural crest cells. Analysis of a targeted null mutation that deleted all Slugh coding sequences revealed that Slugh is not required for mesoderm formation or for neural crest generation, migration, or development in mice. These results indicate that neither the expression pattern nor the biological function of the Slug gene is conserved among all vertebrates. These data also raise interesting questions about the regulation of neural crest generation, which is one of the distinguishing characteristics of the vertebrate subphylum.

Amino Acid Sequence↗
PubMed1998

Glucose-regulated interaction of a regulatory subunit of protein phosphatase 1 with the Snf1 protein kinase in Saccharomyces cerevisiae.

The Snf1 protein kinase family has been conserved in eukaryotes. In the yeast Saccharomyces cerevisiae, Snf1 is essential for transcription of glucose-repressed genes in response to glucose starvation. The direct interaction between Snf1 and its activating subunit, Snf4, within the kinase complex is regulated by the glucose signal. Glucose inhibition of the Snf1-Snf4 interaction depends on protein phosphatase 1 and its targeting subunit, Reg1. Here we show that Reg1 interacts with the Snf1 catalytic domain in the two-hybrid system. This interaction increases in response to glucose limitation and requires the conserved threonine in the activation loop of the kinase, a putative phosphorylation site. The inhibitory effect of Reg1 appears to require the Snf1 regulatory domain because a reg1Delta mutation no longer relieves glucose repression of transcription when Snf1 function is provided by the isolated catalytic domain. Finally, we show that abolishing the Snf1 catalytic activity by mutation of the ATP-binding site causes elevated, constitutive interaction with Reg1, indicating that Snf1 negatively regulates its own interaction with Reg1. We propose a model in which protein phosphatase 1, targeted by Reg1, facilitates the conformational change of the kinase complex from its active state to the autoinhibited state.

Fungal Proteins↗
PubMed1998

Defects in limb, craniofacial, and thymic development in Jagged2 mutant mice.

The Notch signaling pathway is a conserved intercellular signaling mechanism that is essential for proper embryonic development in numerous metazoan organisms. We have examined the in vivo role of the Jagged2 (Jag2) gene, which encodes a ligand for the Notch family of transmembrane receptors, by making a targeted mutation that removes a domain of the Jagged2 protein required for receptor interaction. Mice homozygous for this deletion die perinatally because of defects in craniofacial morphogenesis. The mutant homozygotes exhibit cleft palate and fusion of the tongue with the palatal shelves. The mutant mice also exhibit syndactyly (digit fusions) of the fore- and hindlimbs. The apical ectodermal ridge (AER) of the limb buds of the mutant homozygotes is hyperplastic, and we observe an expanded domain of Fgf8 expression in the AER. In the foot plates of the mutant homozygotes, both Bmp2 and Bmp7 expression and apoptotic interdigital cell death are reduced. Mutant homozygotes also display defects in thymic development, exhibiting altered thymic morphology and impaired differentiation of gamma delta lineage T cells. These results demonstrate that Notch signaling mediated by Jag2 plays an essential role during limb, craniofacial, and thymic development in mice.

Animals↗
PubMed1998

Plasma cholecystokinin-8 in pigs with divergent genetic potential for feed intake and growth.

Plasma cholecystokinin-8 (CCK-8) was studied in pigs with divergent genetic potential for feed intake. Differences in feed intake resulted from selection for either fast (line F) or slow (line S) postweaning gain. The hypothesis was that the relatively lesser feed intake in S versus F may be attributable, in part, to greater circulating concentrations of the putative satiety hormone CCK-8. In Experiment I, barrows from F (n = 23) and S (n = 19) were used to determine changes in CCK-8 associated with ad libitum feed consumption. Blood samples were collected after overnight feed deprivation, then periodically during a 2-hr feeding period. Averaged across sampling times, concentration of CCK-8 tended to be greater (P = 0.07) in S (6.70 pmol/l) than in F (5.06 pmol/l). Concentration of CCK-8 per unit of feed consumed (CCK-8/cumulative feed intake) was greater (P < 0.01) in S than in F during the first 30 min of the feeding period. In Experiment 2, plasma concentrations were determined for nine pairs (F, S) of the same barrows allowed an amount of feed equal to the previous ad libitum intake of the S barrow in the pair. Averaged across times, the difference between CCK-8 concentrations of S (11.65 pmol/l) and F (7.94 pmol/l) barrows was not significant (P = 0.18). A greater concentration of CCK-8 per unit of feed consumed in S than in F supports the hypothesis that satiety effects of CCK-8 may play a role in genetic differences between the lines for feed intake.

Animals↗
PubMed1998

In vitro human epidermal and polyethylene membrane penetration and retention of the sunscreen benzophenone-3 from a range of solvents.

PURPOSE: To study epidermal and polyethylene membrane penetration and retention of the sunscreen benzophenone-3 (BP) from a range of single solvent vehicles and evaluate solvent effects on permeability parameters. METHODS: The solubility of BP was measured in a number of solvents. Penetration of BP across human epidermis and high density polyethylene (HDPE) membranes was studied from 50% saturated solutions in each solvent. RESULTS: Maximal BP fluxes from the solvents across the two membranes varied widely. Highest fluxes were observed from 90% ethanol (EtOH) for epidermis and from isopropyl myristate (IPM) and C12-15 benzoate alcohols (C12-15 BA) for HDPE membrane. Both the flux and estimated permeability coefficient and skin-vehicle partitioning of BP appeared to be related to the vehicle solubility parameter (delta(v)). The major effects of solvents on BP flux appear to be via changes in BP diffusivity through the membranes. CONCLUSIONS: Minimal penetration of sunscreens such as BP is best achieved by choosing vehicles with a delta(v) substantially different to the solubility parameter of the membrane.

Administration, Topical↗
PubMed1998

VH usage and somatic hypermutation in peripheral blood B cells of patients with rheumatoid arthritis (RA).

The human antibody repertoire has been demonstrated to have a marked V-gene-dependent bias that is conserved between individuals. In RA patients, certain heavy chain V genes (VH) have been found to be preferentially used for encoding autoantibodies. To determine if such preferential use of VH genes in autoantibodies is associated with a general distortion of the V gene repertoire in RA patients, the VH composition of peripheral blood B cells was analysed among four RA patients and four age- and sex-matched healthy controls. Usage of individual VH genes (eight VH3 and three VH4 genes tested by hybridization with a set of gene-specific oligonucleotide probes) was highly biased among RA patients, but no evidence of a distortion in the bias was observed compared with healthy controls. However, the occurrence of somatic mutations in these VH genes (estimated by differential hybridization with motif-specific oligonucleotide probes targeted to CDR and FR of the tested genes, and by DNA sequence analysis) was strikingly different between patients and healthy subjects. The number of VH3 rearrangements that had accumulated somatic mutations and the number of mutations per rearrangement were significantly elevated in three of the four RA patients. A slight but not significant elevation in mutations among rearranged VH4 genes was also observed in these patients. These data suggest that although usage of individual VH genes among peripheral blood B cells is not affected by the disease, the autoimmune process may involve a significant fraction of the B cell compartment.

Antibodies↗
PubMed1998

Conjugates of Tremella polysaccharides with microbeads and their TNF-stimulating activity.

A mannan (A) and a heteroglycan (D) were prepared by partial acidic hydrolysis of T3, a major polysaccharide fraction of the fungus Tremella fuciformis Berk. Methylation analysis of A and D showed that they contained a 1-->3 linked mannosyl main chain, to which were linked different side chains at position 2, 4, or 6 of the mannosyl residues. A and D were conjugated to albumin microbeads (AM) by reductive amination. The conjugates showed significant cytokine-stimulating activity in vitro whereas unconjugated AM had no activity. Not conjugated A and D showed cytokine-stimulating activity only in about 100 times higher concentrations.

Basidiomycota↗
PubMed1998

[Secretory expression of salmon calcitonin in Streptomyces lividans].

A gene coding for salmon calcitonin precursor (sCT-Gly) was amplified from salmon genomic DNA by Polymerase Chain Reaction (PCR) and fused to the expression and secretion signals of melC1 amplified by PCR. The fusion gene was cloned into the Streptomyces vector pIJ680 and expressed under the control of aminoglycoside phosphotransferase gene (aph) promoter. Streptomyces lividans TK54 transformed with the expression plasmid (pMS680) secreted biologically active sCT-Gly into the culture medium which was confirmed by Enzyme Immunoassay (EIA) and bioassay. Production of sCT-Gly by the recombinant strain in YEME medium reached a maximum of 100 micrograms/L culture at about 96 h. The recombinant sCT-Gly had almost the same HPLC retention time as the standard sCT obtained from Sigma.

Calcitonin↗
PubMed1998

[Application of IHW2 purged bone marrow to autologous bone marrow transplantation in the treatment of acute myeloid leukemia].

OBJECTIVE: To observe the clinical effectiveness of IHW2 purged autologous bone marrow transplantation (ABMT) in the treatment of AML patients. METHODS: Large volume of bone marrow was purged in vitro by IHW2 and then reinfused to patients for ABMT. RESULTS: All of the three patients transplanted with IHW2 purged autologous bone marrow successfully reconstituted hemopoiesis. Two patients got continuous complete remission for 36+ and 34+ months, respectively. The karyotype of one of the two patient was 46,XY,del(16)(q22) before ABMT and changed to 46,XY in 2 months after transplantation. The third patient relapsed after ABMT 19 months. CONCLUSION: The preliminary study suggests that IHW2 may have certain purging effect on leukemic cells and is safe for clinical application.

Adult↗
PubMed1998

[Treatment of acute optic neuritis with high dose of prednisone].

OBJECTIVE: The benefit of glucocorticoid for the treatment of acute optic neuritis remains controversial. The efficacy of oral prednisone in 12 patients (14 eyes) with acute optic neuritis was reviewed. METHODS: The time of visual symptoms before treatment was 3-15 days. The visual acuities were worse than 0.1 in all patients, with positive relative afferent pupillary defect. Visual field defect and delay latency of P100 in pattern VEP were also found. The regimen of glucocorticoid therapy was oral prednisone, starting with 160 mg daily followed by reducing the dosage by 20 mg every three days until 40 mg per day was attained and then tapering the dosage at 70 mg every other day until stoppage of the drug. The treatment was 3-11 months and 9 patients were followed up more than one year. RESULTS: The visual acuities improved rapidly and stable. After 4 days, the visual acuity was 0.2 or better in 10 eyes. It was better than 0.6 in 12 eyes at 15 days. At 6 months, all had the visual acuity better than 0.7, with 85.7% equal or better than 1.0. CONCLUSIONS: The regimen of oral prednisone beginning with 160 mg followed by tapering for three months would be feasible. Pattern VEP was a sensitive and credible sign for evaluating the extent of demyelination.

Acute Disease↗
PubMed1997

Gene targeting: things go better with Cre.

New technologies are changing the way in which gene targeting experiments are being designed. It is now becoming possible to analyze gene function in defined tissues at specific times during the life of a mouse.

Animals↗