Biomedical subjects

Y Ma

Publications and source records attributed to Y Ma.

At least 289 records · Page 16Linked to original sources

PubMed1999

[Reconstruction and repair after resection of soft tissue sarcoma].

OBJECTIVE: To emphasize the importance of reconstruction and repair after resection of soft tissue sarcoma. METHODS: From November 1990 to November 1996, in 107 cases of soft tissue sarcoma 32 cases had received various reconstructive or reparative operations. Among the 32 cases, 4 cases were primary sarcomas and 28 cases were recurrent sarcomas. In surgical grading, 3 cases were of I B, 3 cases of II A and 26 cases of II B. Radical resection was performed in 13 cases, widen local resection in 17 cases and local excision in 2 cases. After operation, 13 cases received chemotherapy and 7 cases received radiotherapy. Reconstruction of blood vessels was performed in 3 cases, reconstruction of kinetic function in 16 cases, and repair of defect was carried out in 23 cases. RESULTS: Thirty patients were followed up for 4 months to 6 years and 6 months. The clinical results showed that the local control rate of sarcoma was 80%, limb-salvage rate after reconstruction of blood vessels was 100%, the excellent and good rate after reconstruction of kinetic function was 87.5%, and the survival rate of the tissue flap of transplantation and transposition was 96%. CONCLUSION: It was concluded that the reconstruction and repair after resection of soft tissue sarcoma was the extension of operative treatment, and was very important in lowering the recurrence rate and improving the life quality of the sufferings.

Adolescent↗

PubMed1999

[Detection of hepatitis C core antigen C33].

OBJECTIVE: To investigate the distribution of C33 antigen of HCV in serum and liver tissues from normal subjects and patients with different diseases. METHODS: Balb/C mice were immunized by HCV core antigen peptide C33(33 amino acids) which was conjugated with mice serum albzmin by a heterotypic difunctionalconnector(SPDP). Two strains of monoclonal antibody to C33 were produced. By using one of them as coated and the other as HRP(horseradish peroxidase)-labelled antibodies, an ELISA was developed to detect C33 antigen of HCV in 1236 serum samples from patients. RESULTS: The detectable rate of peptide C33 was 14.0%(6/43) in acute hepatitis C group, 8.8%(35/396) in anti-HCV-IgG positive group, 6.5%(4/62) in chronic hepatitis C group, 4.3%(1/23) in leukemia group, 3.3%(19/576) in hemodialysis group, 1.5%(2/136) in other diseases group, and 1. 4%(6/438) in blood donors. Results of immunohistochemistry and immunofluorescence for liver tissues obtained from biopsy showed that C33 peptide was found in nucli, cytoplasm and membranes of hepatic cells, scattered or laterally concentrated in the cytoplasm. CONCLUSION: The detection of C33 antigen of HCV may consider as one of the markers of HCV infection.

Animals↗

PubMed1999

Alteration in enterocyte gene expression may explain structural and functional changes following glutamine supplemented parenteral nutrition.

Following extensive bowel resection, the intestinal tract undergoes a variety of adaptive responses to enhance bowel function. The purpose of this study was to determine the effect of glutamine-supplemented parenteral nutrition on mucosal cellularity and gut function. In addition, enterocyte gene expression of two relevant systems was also characterized and related to the structural and functional changes that occurred. Male Wistar rats underwent a 60% small bowel resection and jugular vein catheterization and were randomized into two groups. The control group (n = 10) received a standard intravenous nutritional solution and the study group (n = 10) received a similar solution but enriched with alanylglutamine dipeptide. After 7 days blood was taken for amino acid analysis, and bowel was harvested to determine mucosal morphology and expression of mucosal cell glutaminase and IGF-I mRNA. Mesentery lymphnodes were cultured to determine the presence of bacteria and thus access bacteria translocation. Serum glutamine concentration and mucosal architecture were maintained in the study group compared to the controls. Seventy percent of lymphnodes were cultured positive in control vs. only 20% in the study group (P < 0.05). Jejunal mucosal glutaminase and ileum mucosal IGF-I mRNA increased twofold and threefold respectively compared to control animals. Parenteral nutrition supplemented with alanyl-glutamine dipeptide supports mucosal cellularity and regional immune function in rodents following intestinal resection, These alterations are associated with enhanced enterocyte expression of glutaminase and IGF-I. These changes may facilitate the structural and functional alterations which were observed in the glutamine treated animals.

Animals↗

PubMed1999

HBV X protein (HBX) interacts with general transcription factor TFIIB both in vitro and in vivo.

OBJECTIVE: In order to demonstrate the binding of HBV X protein (HBX) with the general transcription factor TFIIB. METHODS: In vitro glutathion S-transferase (GST) resin Pull-Down assay and Far-Western Blotting assay, in vivo Co-immunoprecipition assay were used. RESULTS: The X199 (51-99) domain of HBX is reponsible for HBX binding to TFIIB. While the d10 domain (125-295) of TFIIB is required for TFIIB binding to HBX. When the two basic amino acids (K) at position 178 and 189 of TFIIB were substituted by neutral amino acids (L), the binding of TFIIB K178L and K189L to HBX was siginificantly reduced. When the the basic amino acids were substituted by the acidic amino acids (E), the binding of TFIIB K178E and K189E to HBX were almost lost. In vitro results of HBX binding to TFIIB were further confirmed by in vivo co-immunoprecipitation assay. Our results also indicated that the Woodchuck hepatitis virus X protein (WHX) interacts with TFIIB. CONCLUSION: These results suggested that the communication between HBX and general transcription factor TFIIB is one of the mechanisms which account for its transcriptional transactivation.

Binding Sites↗

PubMed1999

[Induction of osteointegration of rabbit mandibular central fissure with guided tissue regeneration]

OBJECTIVE:To observe the effect of guided tissue regeneration (GTR) on induction of ostegenesis in developmental bone clefts,and provide a basis for the use of GTR to repair bony clefts in cleft lip and palate patients.METHODS:The e-PTFE membrane was placed on the labial and lingual sides of the rabbit mandibular central fissure.A radiological and pathological study was performed to determine the healing of the fissure integration.RESULTS:The results showed that the bony cleft was completely integrated 4 weeks after placement of the barrier membrane.CONCLUSION:GTR is an effective approach to reconstruct bony cleft,and is likely to be used in repair of alveolar cleft and cleft palate.

Journal Article↗

PubMed1999

[Synthesis of methyl ester of aliphatic acid under irradiation of ultraviolet and mass spectra (MS) analysis].

A new method was introduced here to prepare methyl ester of aliphatic acid under irradiation of ultraviolet. Analysis was performed for the MS spectra of 19 products, by which Mclafferty rearrangements were discussed of methyl ester of aliphatic acid with two kinds of gamma-H in details. The regularity of Mclafferty rearrangement was established for the same kind of methyl ester with the increase of the carbon chain.

English Abstract↗

PubMed1998

[A rapid method for subtractive screening of hepatoma apoptotic cells cDNA library].

OBJECTIVE: To expedite the subtractive screening of human hepatoma apoptotic cells cDNA library. METHODS: The method of subtractive hybridization combined with dot blot hybridization was adopted. First, minus cDNA probe was used to screen the cDNA library, the minus clones that did not hybridize with the minus cDNA probe were picked up as the source of the second grade dot blot hybridization. Secondly, two probes of the plus and minus cDNA were used to screen the clones;the clones that only hybridize with the plus cDNA probe were picked up as the source of the third grade dot blot hybridization. RESULTS: Four clones were obtained and the lengths of the inserted cDNA fragments were about 1.5kb long. CONCLUSION: The results demonstrate this is a feasible, simple and quick method for subtractive screening of the cDNA library.

Apoptosis↗

PubMed1998

Nutritional and socioeconomic factors in relation to prostate cancer mortality: a cross-national study.

BACKGROUND: Large international variations in rates of prostate cancer incidence and mortality suggest that environmental factors have a strong influence on the development of this disease. The purpose of this study was to identify predictive variables for prostate cancer mortality in data from 59 countries. METHODS: Data on prostate cancer mortality, food consumption, tobacco use, socioeconomic factors, reproductive factors, and health indicators were obtained from United Nations sources. Linear regression models were fit to these data. The influence of each variable fit in the regression models was assessed by multiplying the regression coefficient b by the 75th (X75) and 25th (X25) percentile values of the variable. The difference, bX75 - bX25, is the estimated effect of the variable across its interquartile range on mortality rates measured as deaths per 100000 males aged 45-74 years. Reported P values are two-sided. RESULTS: Prostate cancer mortality was inversely associated with estimated consumption of cereals (bX75 - bX25 = -7.31 deaths; P = .001), nuts and oilseeds (bX75 - bX25 = -1.72 deaths; P = .003), and fish (bX75 - bX25 = -1.47 deaths; P = .001). In the 42 countries for which we had appropriate data, soy products were found to be significantly protective (P = .0001), with an effect size per kilocalorie at least four times as large as that of any other dietary factor. Besides variables related to diet, we observed an association between prostate cancer mortality rates and a composite of other health-related, sanitation, and economic variables (P = .003). CONCLUSIONS: The specific food-related results from this study are consistent with previous information and support the current dietary guidelines and hypothesis that grains, cereals, and nuts are protective against prostate cancer. The findings also provide a rationale for future study of soy products in prostate cancer prevention trials.

Animals↗

PubMed1998

Phosphorylation and activation of cAMP-dependent protein kinase by phosphoinositide-dependent protein kinase.

Although phosphorylation of Thr-197 in the activation loop of the catalytic subunit of cAMP-dependent protein kinase (PKA) is an essential step for its proper biological function, the kinase responsible for this reaction in vivo has remained elusive. Using nonphosphorylated recombinant catalytic subunit as a substrate, we have shown that the phosphoinositide-dependent protein kinase, PDK1, expressed in 293 cells, phosphorylates and activates the catalytic subunit of PKA. The phosphorylation of PKA by PDK1 is rapid and is insensitive to PKI, the highly specific heat-stable protein kinase inhibitor. A mutant form of the catalytic subunit where Thr-197 was replaced with Asp was not a substrate for PDK1. In addition, phosphorylation of the catalytic subunit can be monitored immunochemically by using antibodies that recognize Thr-197 phosphorylated enzyme but not unphosphorylated enzyme or the Thr197Asp mutant. PDK1, or one of its homologs, is thus a likely candidate for the in vivo PKA kinase that phosphorylates Thr-197. This finding opens a new dimension in our thinking about this ubiquitous protein kinase and how it is regulated in the cell.

3-Phosphoinositide-Dependent Protein Kinases↗

PubMed1998

Characterization of a novel human natural killer-cell line (NK-YS) established from natural killer cell lymphoma/leukemia associated with Epstein-Barr virus infection.

A novel cell line was established from a patient with a leukemic-state nasal angiocentric natural killer (NK) cell lymphoma with systemic skin infiltration. The morphology of the leukemic cells was large-granular-lymphocyte (LGL), and their immunophenotype was CD2+, CD3-, CD5+, CD7+, CD16-, CD56+, and CD57-. The presence of Epstein-Barr viral (EBV) genome was shown in specimens from the patient's nose, skin, and peripheral blood by in situ hybridization using an EBV-encoded small RNA-1 probe or by Southern blotting using a terminal-repeat probe of the EBV genome. Leukemic cells were cocultured with a mouse stromal cell line (SPY3-2) in the presence of 100 U/mL recombinant human interleukin-2 and a novel stromal cell-independent cell line, NK-YS, was established. The NK-YS cells showed LGL morphology and expressed surface CD2, CD5, CD7, CD25, CD56, and CD95. The NK-YS cells retained cytotoxicity against K562 and Jurkat cells. A Southern blotting using a terminal-repeat probe of EBV showed that NK-YS and fresh leukemic cells had a clonal EBV genome, whereas the T-cell receptor beta and gamma chain genes of NK-YS were not rearranged. In an immunocytochemical analysis, the NK-YS cells showed a type-II latent infection of EBV. The NK-YS cells preserved the original characteristics of NK cell lymphoma/leukemia and will be a useful tool for the study of biological characteristics of EBV-associated nasal angiocentric NK cell lymphoma/leukemia.

Adult↗

PubMed1998

Inhibition of collagen-induced arthritis in mice by viral IL-10 gene transfer.

Autoimmune arthritides are characterized by an imbalance between pro- and anti-inflammatory cytokines. Viral IL-10 (vIL-10) shares many of the anti-inflammatory properties of mouse and human IL-10, but lacks their immunostimulatory properties and may therefore offer superior immunosuppression. Viral IL-10 has a short half-life; however, genetic modification of cells in vivo offers a potential means of achieving prolonged therapeutic titers. To determine the effects on collagen-induced arthritis of vIL-10 gene transfer, DBA/1 mice were administered i.v. or intra-articular injections of Av(vIL-10), a replication-deficient adenovirus encoding vIL-10. The i.v. injection of Av(vIL-10) before disease onset delayed the onset and reduced the severity of collagen-induced arthritis, but treatment of established disease was ineffective. The preventative effects were not due to decreased anti-type II collagen Ab production. Rather, T cells from mice treated with Av(vIL-10) demonstrated a decreased in vitro proliferative response to type II collagen, and a delay was observed in up-regulation of synovial mRNA for the proinflammatory cytokines IL-2 and IL-1beta. Intra-articular injection of Av(vIL-10) into knee joints did not reduce arthritis in the knees, but inhibited the development of arthritis in the paws. Humoral and cellular immune responses against Av(vIL-10) were observed. These results demonstrate that vIL-10 can significantly alter the course of autoimmune arthritis and emphasize the complexities of using gene transfer as a method of drug delivery for arthritis.

Adenoviridae↗

PubMed1998

A schizophrenia locus may be located in region 10p15-p11.

In our genomic scan of 265 Irish families with schizophrenia, we have thus far generated modest evidence for the presence of vulnerability genes in three chromosomal regions, i.e., 5q21-q31, 6p24-p22, and 8p22-p21. Outside of those regions, of all markers tested to date, D10S674 produced one of the highest pairwise heterogeneity lod (H-LOD) scores, 3.2 (P = 0.0004), when initially tested on a subset of 88 families. We then tested a total of 12 markers across a region of 32 centimorgans in region 10p15-p11 of all 265 families. The strongest evidence for linkage occurred assuming an intermediate phenotypic definition, and a recessive genetic model. The largest pairwise H-LOD score was found with marker D10S2443 (maximum 1.95, P = 0.005). Using multipoint H-LODs, we found a broad peak (maximum 1.91, P = 0.006) extending over the 11 centimorgans from marker D10S674 to marker D10S1426. Multipoint nonparametric linkage analysis produced a much broader peak, but with the maximum in the same location near D10S2443 (maximum z = 1.88, P = 0.03). Based on estimates from the multipoint analysis, this putative vulnerability locus appears to be segregating in 5-15% of the families studied, but this estimate should be viewed with caution. When evaluated in the context of our genome scan results, the evidence suggests the possibility of a fourth vulnerability locus for schizophrenia in these Irish families, in region 10p15-p11.

Chromosome Mapping↗

PubMed1998

Complement-inhibiting cucurbitacin glycosides from Picria fel-terrae.

Four cucurbitacin glycosides were isolated from Picriafel-terrae and identified by MS and NMR spectroscopy as picfeltarraenin IA (1), picfeltarraenin IB (2), picfeltarraenin IV (4), and a new compound picfeltarraenin VI (3) (picfeltarraegenin I 3-O-beta-D-xylopyranoside). All four compounds acted as inhibitors on both the classical and alternative pathways of the complement system, with compound 3 exhibiting the highest inhibitory activity (IC50 29 +/- 2 microM and 21 +/- 1 microM, respectively). Compounds 1-4 showed no antiviral, antibacterial, or antifungal activities. Picfeltarraenin IA and IB were tested in an in vitro human tumor cell line panel, but displayed no cytotoxic activity.

Anti-Infective Agents↗

PubMed1998

Toroidal coil counter-current chromatography study of the mass transfer rate of proteins in aqueous-aqueous polymer phase system.

The cause of excessive band broadening of protein samples in polymer phase partitioning by counter-current chromatography (CCC) was investigated. A simple rotary device was constructed to measure the mass transfer rates of five samples including potassium dichromate, methylene blue, lysozyme, ovalbumin and human serum albumin. The results indicated that the mass transfer rates of these samples are closely correlated with their molecular masses: the higher the molecular mass, the lower the mass transfer rate. These findings are also consistent with the partition efficiencies of these samples in the same solvent system by CCC. The beneficial effect of the Coriolis force demonstrated in protein separations by the toroidal coil centrifuge may be reasonably explained on the basis of the mass transfer resistance of protein molecules through the interface: we speculate that when the Coriolis force acts parallel to the effective coil segment it can produce large interfacial areas by dispersing the mobile phase into the stationary phase, thus accelerating the mass transfer rate of protein samples.

Chromatography, Liquid↗

PubMed1998

Differentiation-stimulated activity binds an ETS-like, essential regulatory element in the human promyelocytic defensin-1 promoter.

The human HNP-defensin-1 gene encodes a peptide antibiotic found exclusively in neutrophils and is key to elimination of microbes. Expression is a marker for the granulocytic lineage and for certain stages of differentiation and is not known to be inducible in mature cells under physiological conditions. Low level of transcription also occurs in HL-60 promyelocytic leukemia cells and is greatly activated upon drug-induced granulocytic maturation and by low doses of retinoic acid, in a strictly cell-specific manner (Herwig, S., Su, Q., Ma, Y., and Tempst, P. (1996) Blood 87, 350-364). We have analyzed a 10-kilobase pair region, upstream of the defensin-1 cap site, for the presence of control elements, and we describe a minimal promoter (position -83 to +82) required to drive transcription in HL-60 cells in a quasi cell-specific manner. Our data also suggest the presence of negative regulatory elements in the -416/-191 region that may further contribute to cell specificity in a chromosomal context. The basal promoter contains two functionally essential, ETS-like (GGAA core sequence) elements. The proximal site (-22/-19) constitutively binds the PU.1 transcription factor in vitro and could function, together perhaps with an adjacent TA-rich sequence (-32/-25), in assembly of a myeloid-restricted, basal transcription factor complex. The distal site (-62/-59) interacts in vitro with an unidentified activity, distinct from PU.1, ETS-1, PEA3, and ELK-1 (factors with definite binding site similarities), and is greatly stimulated by phosphorylation during granulocytic differentiation of HL-60 cells. Identification of this protein will be important to resolve the molecular mechanisms controlling temporal, granulocytic restricted gene expression.

Amino Acid Sequence↗

PubMed1998

Mycophenolate mofetil: a promising new immunosuppressant that does not cause bone loss in the rat.

BACKGROUND: Posttransplantation bone disease is a well-described phenomenon; among its etiology is immunosuppressant-induced bone disease. Mycophenolate mofetil (MMF) has emerged as a promising new immunosuppressant. Our study was designed to investigate the effect of MMF on in vivo bone mineral metabolism. METHODS: Twenty-four 6-month-old male Sprague-Dawley rats were randomized into two groups to receive either MMF vehicle daily for 28 days or 30 mg/kg MMF daily for 28 days. The serum was assayed for osteocalcin and 1,25-dihydroxy vitamin D3. Subsequent to double-labeling, the right tibiae were removed on day 28 for histomorphometry. RESULTS: MMF suppressed bone gla protein (osteocalcin) levels on days 14 and 28 (P < 0.05). Except for percentage osteoid perimeter, there was no difference in bone histomorphometry between the two groups. CONCLUSION: In this relatively short-term study, MMF did not cause osteopenia in the rat model, but the suppressed bone gla protein merits further study.

Animals↗

PubMed1998

The risk for early-adulthood anxiety and depressive disorders in adolescents with anxiety and depressive disorders.

BACKGROUND: Various studies find relationships among anxiety and depressive disorders of adolescence and adulthood. This study prospectively examines the magnitude of longitudinal associations between adolescent and adult anxiety or depressive disorders. METHODS: An epidemiologically selected sample of 776 young people living in upstate New York received DSM-based psychiatric assessments in 1983, 1985, and 1992 using structured interviews. The magnitude of the association between adolescent and adult anxiety or depressive disorders was quantified using odds ratios generated from logistic regression analyses and from a set of latent Markov analyses. We focus on longitudinal associations among narrowly defined DSM anxiety or depressive disorders. RESULTS: In simple logistic models, adolescent anxiety or depressive disorders predicted an approximate 2- to 3-fold increased risk for adulthood anxiety or depressive disorders. There was evidence of specificity in the course of simple and social phobia but less specificity in the course of other disorders. Results from the analyses using latent variables suggested that while most adolescent disorders were no longer present in young adulthood, most adult disorders were preceded by adolescent disorders. CONCLUSIONS: An anxiety or depressive disorder during adolescence confers a strong risk for recurrent anxiety or depressive disorders during early adulthood. Most anxiety and depressive disorders in young adults may be preceded by anxiety or depression in adolescence.

Adolescent↗

PubMed1998

Altered susceptibility to collagen-induced arthritis in transgenic mice with aberrant expression of interleukin-1 receptor antagonist.

OBJECTIVE: To determine the effect of overexpression or deletion of interleukin-1 receptor antagonist (IL-1Ra) in collagen-induced arthritis (CIA). METHODS: Mice overexpressing the IL-1Ra gene under the control of its endogenous promoter, mice lacking IL-1Ra, and normal littermate controls were immunized with bovine type II collagen (CII) and compared in terms of features of CIA. RESULTS: Mice overexpressing IL-1Ra had a significant reduction in the incidence and severity of CIA. After CII immunization, IL-1Ra messenger RNA was overexpressed in the spleens, but not in the paws, of transgenic mice. Minimal differences were observed in the humoral or cellular immune responses to CII. Mice lacking IL-1Ra had a significantly earlier onset of CIA, with increased severity. CONCLUSION: Endogenous expression of IL-1Ra is a critical determinant of susceptibility to CIA. These findings suggest potential therapeutic interventions for autoimmune arthritis.

Animals↗