Biomedical subjects

X Tang

Publications and source records attributed to X Tang.

At least 181 records · Page 10Linked to original sources

PubMed1998

[Comparison of Botox and a Chinese type a botulinum toxin in cervical dystonia].

OBJECTIVE: To confirm and compare the therapeutic efficacy of a Chinese type A botulinum toxin (CBTX-A, made by Lanzhou Biological Products Institute) and Botox (from Allergan Inc.) for cervical dystonia. METHODS: Prospective open study over 3 years for cervical dystonia was analyzed. We treated 113 patients with medically intractable cervical dystonia in two groups during 1993-1996, 32 patients with Botox and 81 with CBTX-A, with the age, durations and severity (Tsui's scale) matched. Some patients were injected under EMG guidance if necessary. The patients enrolled were followed up for 6-42 months. RESULTS: Considerable improvement of symptoms for the CD patients was observed with either Botox or CBTX-A. The Tsui scores showed a significant reduction after BTX-A injections. There were no significant differences in the clinical effects of two preparations, including the latency of response, maximal benefit, and duration of improvement. The patients' subjective assessments were similar. But the requested dose of Chinese preparation which produced the similar effects was statistically higher than that of Botox. Skin rash appeared within a few days after injections in 3 cases of CBTX-A group, but no one in Botox group. No statistical differences were noted in the other adverse reaction between them. CONCLUSION: The injections of two kinds of preparation both were simple and effective for the patients with cervical dystonia. Chinese preparation is a little less powerful but much cheaper than Botox.

Adolescent↗

PubMed1998

[10-Hydroxycamptothecin induces apoptosis in human T24 urinary bladder cancer cells].

OBJECTIVE: To study the emechanisms of 10-Hydroxycamptothecine (HPT) inhibiting human urinary bladder cancer. METHODS: Using flow cytometry, electron microscopy and fluorescence microscopy, we studied the effects of HPT on human T24 urinary bladder cancer cells. RESULTS: HPT at 0.005 mg/L inhibited T24 bladder cancer cells by preventing the cells from S phase to G2/M phase and did not induce apoptosis. The apoptotic cells were induced by HPT at the concentration of 0.01-0.10 mg/L. CONCLUSION: HPT can inhibit human T24 urinary bladder cancer cells and induced apoptosis at some concentrations. The induction of apoptosis is a very important mechanism of 10-Hydroxycamptothecine to treat urinary bladder cancer cells.

Antineoplastic Agents, Phytogenic↗

PubMed1998

[DNA typing for HLA-A, B antigens by polymerase chain reaction with sequence-specific primers and clinical application].

OBJECTIVE: To establish DNA typing for HLA-A, B antigens in Chinese by polymerase chain reaction with sequence-specific primers (PCR-SSP). METHODS: DNA samples were obtained from 178 unrelated donors and 167 kidney recipients. An additional panel of 62 standard DNAs that were typed by UCLA tissue typing lab in USA. A rapid genotyping for HLA-I class (A, B antigens) by PCR-SSP was set up by designed and synthesized 81 specific primers and 1 pair of internal control primer, combining in 61 one-step reactions (20 PCR reactions for A alleles, 41 PCR reactions for B alleles). RESULTS: HLA-A, B alleles were successfully typed in 345 clinical samples and 62 standard DNAs by PCR-SSP technique. No false positive or false negative typing results were obtained. Reproducibility was 100% in 40 samples. The overall time of DNA typing was 5 hours. The typing results were consistent with those of UCLA tissue typing lab. Nineteen alleles of HLA-A and 41 HLA-B alleles were accurately distinguished. Thirteen HLA-A alleles and thirty-two HLA-B alleles in Chinese were practically typed. CONCLUSION: DNA typing for HLA-I class (A, B antigens) by PCR-SSP has proved to be a technique of high-resolution, high-specificity, well-reproducibility, and more suitable for clinical application than serology.

Adolescent↗

PubMed1998

Ultrastructural evidence for vulnerability of hip region to fracture in the aged.

OBJECTIVE: To probe ultrastructurally into the mechanism why hip region is the predilected site of fracture in aged people, yet with femoral head exempted. METHODS: Proximal femoral ends were collected from 14 aged people, who had undergone endoprosthetic replacement for intra-capsular fracture of the femoral neck, and from 7 young men died of brain injury. These specimens were processed and subjected to scanning electron microscopic and transmission electron microscopic observation for bone resorption. RESULTS: As compared with the specimens from young men, there were three types of bone resorption in the proximal femoral ends of aged people, i.e. osteoclastic resorption and osteocytic resorption of the trabeculae of cancellous bone, and osteoclastic resorption of Haversian systems of the cortical bone. In the proximal femoral ends of the young men, the arch structures composed of trabeculae in the femoral head showed a round or roundish configuration, while those at the femoral head-neck junction revealed an oval profile and those in the femoral neck exhibited a narrow oval contour. In the proximal femoral ends of the aged people, the morphological characteristics of the trabecular arch remained unchanged despite overt bone resorption. CONCLUSIONS: Vulnerability of hip region to fracture in aged people is due to a decline in the structural strength of bone tissues of the proximal femoral ends resulting from osteoclastic and osteocytic resorption. The round and roundish trabecular arch of the femoral head can bear external forces from different directions, so that no fracture occurs here, while the oval and narrow oval arches at the head-neck junction and in the neck region fail to stand the horizontal external forces (abduction and adduction injuries), thereby fracture easily happens.

Adult↗

PubMed1998

[A comparative study of serological, monoclonal antibody and DNA typing in identifying HLA-A].

OBJECTIVE: A double-blind study was carried out to evaluate the accuracy and reliability of PCR-SSP assay in comparison with serology and monoclonal antibody(mAb) typing in identifying HLA-A alleles in Southern Chinese population. METHODS: A total of 296 samples were entered into the study, including 143 unrelated kidney donors and 153 recipients. HLA-A typing was performed by standard two-stage microlymphocytotoxicity assay, one-step mAb typing and PCR-SSP typing. RESULTS: All samples were successfully typed by PCR-SSP. Reproducibility was 100%. The results were confirmed by a panel of standard DNAs and a double-blind typing of UCLA tissue typing lab. However, mAb typing(for Asian) in 149 samples showed 2.7% misassignment including 1 antigen being incorrectly interperted and 3 of 26 "blanks" turning out to be definable alleles by DNA typing. Serological discrepancy rate was 15.6% in 147 samples consisting of 8 antigens being incorrectly interpreted, 13 "blanks" turning out to be definable alleles and 2 heterozygotes turning out to be homozygotes by DNA typing. CONCLUSION: HLA-A typing by PCR-SSP proved to be a rapid and accurate technique, suitable for clinical application with a greater precision than serology. In large scale screening, mAb typing (for Asian) is recommended. Antigens of "blanks" or "difficult" by serology or mAb typing should be retyped by DNA typing.

Alleles↗

PubMed1998

[Detection of interleukin-8 level in peripheral blood of patients with aplastic anemia].

OBJECTIVE: To investigate the role of interleukin-8 in the pathogenesis of aplastic anemia (AA) and its correlation with clinical status. METHODS: Serum level of IL-8 in 24 AA patients and 20 normal controls was measured by sandwich enzyme linked immunosorbent assay(ELISA). RESULTS: The levels of IL-8 were increased significantly(P < 0.05) in AA patients than in normal controls, and the IL-8 levels in severe AA group were much higher than those in chronic AA group (P < 0.05). Serum IL-8 in AA patients with infection were elevated significantly(P < 0.005). CONCLUSION: IL-8 may have a potential role in the pathogenesis of AA and determination of serum IL-8 may be helpful for evaluation of severity and infectious complication of AA.

Adolescent↗

PubMed1998

[Comparison of pharmacological effects between cultispecies Sichuan Fritillary bulb (F. wabueasis, F. mellea) and wild Sichuan Fritillary bulb (F. unibracteata)].

The ethanol extracts from the cultured Sichuan Fritillary bulb have been proved similar to those from the wild one in treating coughing in mice, expectoration in rats, asthma in guinea pigs, bronchodilation of isolated lungs in mice, and cyclic nucleotide(cAMP, cGMP) in the plasma and lungs of mice. The acute toxicity of the cultured and wild species is also similar to each other. However, in terms of asthma relieving and cAMP level increment in the lungs, the cultured species F. wabueasis is significantly superior to the wild species of Fritillary bulb.

Animals↗

PubMed1998

Phrenic nerve conduction and diaphragmatic motor evoked potentials: evaluation of respiratory dysfunction.

OBJECTIVE: To investigate preliminarily the value of phrenic nerve conduction (PNC) and diaphragmatic motor evoked potentials (MEPs) in the evaluation of various respiratory dysfunction (RDF). METHODS: Thirty-four patients with various RDF, (19 patients with neurogenical diseases and 15 patients with respiratory disorders) were investigated. Fifty healthy volunteers served as controls. The phrenic nerve was cutaneously stimulated by electrical pulse current at the midpoint of the posterior border of the sternomastoid muscle, and the diaphragmatic muscle compound action potentials (DCAP) were recorded between the 7th and 8th intercostal space and xiphoid process. When the magnetic transcranial stimulation (MTS) of the cortex was given, the recordings were made under the condition of maximal deep inspiration. RESULTS: All patients with myopathies had normal PNC. The patients with Guillain Barre syndrome (GBS), hereditary motor and sensory neuropathy (HMSN) and myasthenic crisis had abnormal PNC. The findings in PNC studies remarkably correlated with RDF, while serial examinations were performed in the patients with GBS and myasthenia gravis (MG). In 7 patients with sleep apnea syndrome (SAS), 4 had abnormal PNC, and 2 of 3 patients with chronic obstructive pulmonary diseases (COPD), and 1 of 5 patients with chest tightness or breathlessness on the supine position showed decreased amplitude. When MEPs were recorded, 3 of 5 patients showed abnormal SAS (1 had no response, 2 lower amplitude). Three patients with COPD had normal MEP. CONCLUSIONS: PNC studies could not only evaluate neuromuscular RDF and predict the outcome of diseases, but also supply additional information about diaphragmatic dysfunction for the RDF caused by respiratory disorders. The results of PNC and diaphragmatic MEP may differentiate the types of SAS.

Adolescent↗

PubMed1998

EMG study in the diagnosis and differential diagnosis of lipid storage myopathy.

Clinical, electromyographic and pathological features were studied in 18 patients with lipid storage myopathy (group I) and 18 patients with polymyositis and dermatomyositis (group II). The results showed a remarkable lower spontaneous activity(SA) incidence (14%) in group I than that (55%) in group II; 46% and 34% short-duration motor unit potentials(MUAPs) with polyphasic potentials and 74% and 71% short-duration MUAPs without polyphasic potentials respectively; the percentages of increased polyphasic MUAPs were same in the two groups. The reduced or pathologic interference patterns accounted for 61% in the group I and 50% in group II. Increased CPK, LDH and HBD were also found in both of them. It is suggested that the lipid storage myopathy may be diagnosed when patients have muscle weakness and myalgia with short-duration and low-amplitude and polyphasic MUAPs without or with occasional spontaneous activities, and increased CPK, LDH and HBD.

Adolescent↗

PubMed1998

[The degeneration and regeneration of skeletal muscle after tenotomy].

In order to investigate the degeneration and regeneration of skeletal muscle fiber after tenotomy, the tenotomy were carried out on gastrocnemius muscles in 15 adult BALB/C mice. The tenotomized muscles were removed on 1, 2 and 4 weeks postoperatively. Specimens were processed for histological study with light microscope and TEM, and skeletal muscle specific protein expression analysis with myoactin (MA) and myoglobin (MG) immunohistochemical staining. The results showed that the regenerating muscle cells and the degenerating muscle fibre coexisted in tenotomized muscle. The internal structure and histochemical pattern of muscle fiber changed after tenotomy. The regenerating muscle cells fused with degenerating fibres.

Actins↗

PubMed1998

[A method for standardizing brain CT image].

In this paper, we propose the concept of standardization of brain CT image and introduce a kind of standardization method based on geometry correction technique. To work out the method, first we preprocessed the raw CT image, second automatically searched the control points which were used for establishing the correction equation, and last we completed the standardization of the CT image. The result of the experiments demonstrated the pracficability efficiency of this kind of method which conld provide theoretical foundation and experimental means for the diagnosis of brain disease.

Algorithms↗

PubMed1998

[Appllcation of PYGC and the hierarchical clustering analysis to recognization of viruses].

The pyrolysis gas chromatography of 29 strains nuclear polyhedrosis viruses, 11 strains cytoplasmic polyhedrosis viruses and 16 strains granulosis viruses were performed on a shimadzu GV-9A capillary gas chromatography equipped with a pyrolyser model PYR-2A. The differences among the inclusion bodies of NPV, CPV and GV could clearly be distinguished and also beidentified through analysis of fingerprinting the hierarchical clustering analysis of GC, This procedure has provided a usefel method for the classification and identification of viruses.

Algorithms↗

PubMed1997

Outside-in signaling in the chondrocyte. Nitric oxide disrupts fibronectin-induced assembly of a subplasmalemmal actin/rho A/focal adhesion kinase signaling complex.

Elevated levels of fibronectin (Fn) in articular cartilage have been linked to the progression of both rheumatoid and osteoarthritis. In this study, we examined intracellular events which follow ligation of Fn to its receptor, the integrin alpha5beta1. In addition, we examined the regulatory influence of nitric oxide on these events, since this free radical has been implicated in cartilage degradation. Exposure of chondrocytes to Fn-coated beads resulted in the circumferential clustering of the alpha5beta1 integrin receptor, which was accompanied by the subplasmalemmal assembly of a focal activation complex comprised of F-actin, the tyrosine kinase, focal adhesion kinase (FAK), the ras related G protein rho A, as well as tyrosine-phosphorylated proteins. Treatment with exogenous nitric oxide (NO) or catabolic cytokines which induce nitric oxide synthase blocked the assembly of F-actin, FAK, rho A and tyrosine-phosphorylated proteins while not affecting the total number of beads bound per cell nor the clustering of alpha5beta1 integrin. Use of a cGMP antagonist (Rp-8-Br cGMPS) or cGMP agonist (Sp-cGMPS) either abolished or mimicked the NO effect, respectively. Adherence of chondrocytes to fibronectin enhanced proteoglycan synthesis by twofold (vs. albumin). In addition, basic fibroblast growth factor (FGF) and insulin growth factor (IGF-1) induced proteoglycan synthesis in chondrocytes adherent to Fn but not albumin suggesting a costimulatory signal transduced by alpha5betal and the FGF receptor. Both constitutive and FGF stimulated proteoglycan synthesis were completely inhibited by nitric oxide. These data indicate that the ligation of alpha5beta1 in the chondrocyte induced the intracellular assembly of an activation complex comprised of the cytoplasmic tail of alpha5beta1 integrin, actin, and the signaling molecules rho A and FAK. We show that NO inhibits the assembly of the intracellular activation complex and the synthesis of proteoglycans, but has no effect on the extracellular aggregation of alpha5beta1 integrin. These observations provide a basis by which nitric oxide can interfere with chondrocyte functions by affecting chondrocyte-matrix interactions.

Actins↗

PubMed1997

The Pto kinase conferring resistance to tomato bacterial speck disease interacts with proteins that bind a cis-element of pathogenesis-related genes.

In tomato, the Pto kinase confers resistance to bacterial speck disease by recognizing the expression of a corresponding avirulence gene, avrPto, in the pathogen Pseudomonas syringae pv. tomato. Using the yeast two-hybrid system, we have identified three genes, Pti4, Pti5 and Pti6, that encode proteins that physically interact with the Pto kinase. Pti4/5/6 each encode a protein with characteristics that are typical of transcription factors and are similar to the tobacco ethylene-responsive element-binding proteins (EREBPs). Using a gel mobility-shift assay, we demonstrate that, similarly to EREBPs, Pti4/5/6 specifically recognize and bind to a DNA sequence that is present in the promoter region of a large number of genes encoding 'pathogenesis-related' (PR) proteins. Expression of several PR genes and a tobacco EREBP gene is specifically enhanced upon Pto-avrPto recognition in tobacco. These observations establish a direct connection between a disease resistance gene and the specific activation of plant defense genes.

Amino Acid Sequence↗

PubMed1997

Purification and characterization of Gbetagamma-responsive phosphoinositide 3-kinases from pig platelet cytosol.

A G-protein betagamma subunit (Gbetagamma)-responsive phosphoinositide 3-kinase (PI 3-kinase) was purified approximately 5000-fold from pig platelet cytosol. The enzyme was purified by polyethylene glycol precipitation of the cytosol followed by column chromatography on Q-Sepharose fast flow, gel filtration, heparin-Sepharose, and hydroxyapatite. The major Gbetagamma-responsive PI 3-kinase is distinct from p85 containing PI 3-kinase as the activities can be distinguished chromatographically and immunologically and is related to p110gamma as it cross-reacts with anti-p110gamma-specific antibodies. The p110gamma-related PI 3-kinase cannot be activated by G-protein alphai/o subunits, and it has an apparent native molecular mass of 210 kDa. The p110gamma-related PI 3-kinase phosphorylates phosphatidylinositol (PtdIns), phosphatidylinositol 4-phosphate (PtdIns4P), and phosphatidylinositol 4,5-bisphosphate (PtdIns(4,5)P2). The apparent Km values for ATP were found to be 25 microM with PtdIns, 44 microM with PtdIns4P, and 37 microM with PtdIns(4,5)P2 as the substrate. Gbetagamma subunits did not alter the Km of the enzyme for ATP; however, Vmax increased 2-fold with PtdIns as substrate, 3.5-fold with PtdIns4P, and 10-fold with PtdIns(4,5)P2. Under basal conditions the apparent Km values for lipid substrates were 64, 10, and 15 microM for PtdIns, PtdIns4P, and PtdIns(4,5)P2, respectively. In the presence of Gbetagamma subunits the dependence of PI 3-kinase activity on the concentrations of lipid substrates became complex with the highest level of stimulation occurring at high substrate concentration, suggesting that the binding of Gbetagamma and lipid substrate (particularly PtdIns(4,5)P2) may be mutually cooperative. Wortmannin and LY294002 inhibit the Gbetagamma-responsive PI 3-kinase activity with IC50 values of 10 nM and 2 microM, respectively. Unlike the p85 containing PI 3-kinase in platelets, the p110gamma-related PI 3-kinase is not associated with a PtdIns(3,4,5)P3 specific 5-phosphatase. The p85-associated PI 3-kinase was not activated by Gbetagamma alone but could be synergistically activated by Gbetagamma and phosphotyrosyl platelet-derived growth factor receptor peptides. This may represent a form of coincidence detection through which the effects of tyrosine kinase and G-protein-linked receptors might be coordinated.

Androstadienes↗

PubMed1997

Identification of a novel Ca2+-dependent, phosphatidylethanolamine-hydrolyzing phospholipase D in yeast bearing a disruption in PLD1.

We have previously reported the identification and partial characterization of a gene encoding a phospholipase D activity (PLD1) in the yeast, Saccharomyces cerevisiae. Here we report the existence of a second phospholipase D activity, designated PLD2, in yeast cells bearing disruption at the PLD1 locus. PLD2 is a Ca2+-dependent enzyme which preferentially utilizes phosphatidylethanolamine over phosphatidylcholine as a substrate. In contrast to PLD1, the activity of PLD2 is insensitive to phosphatidylinositol 4,5-bisphosphate, and the enzyme is incapable of catalyzing the transphosphatidylation reaction with short chain alcohols as acceptors. Subcellular fractionation shows that PLD2 localizes mainly to the cytosol, but could also be detected in the particulate fraction. Thus, the biochemical properties of PLD2 appear to be substantially different from those of PLD1. PLD2 activity is significantly and transiently elevated upon exit of wild type yeast cells from stationary phase, suggesting that it may play a role in the initiation of mitotic cell division in yeast. In view of the significantly different properties of PLD1 and PLD2, and because the yeast genome contains PLD1 as the sole member of the recently defined PLD gene family, it may be concluded that PLD2 is structurally unrelated to PLD1. Thus, the novel PLD2 activity described herein is likely to represent the first identified member of a new PLD gene family.

Calcium↗

PubMed1997

Compact tunable Cr:LiSAF laser for infrared matrix-assisted laser desorption/ionization.

A tunable Cr:LiSAF laser-pumped optical parametric oscillator was used for mid-infrared matrix-assisted laser desorption/ionization (MALDI) mass spectrometry experiments. The mass spectra of substance P, bovine insulin and pd(T)10 in the 2.88-2.96 microns range showed excellent single shot signal quality (signal-to-noise-ratio, resolution) but poor shot-to-shot reproducibility. The reproducibility is expected to improve with more stable laser design. No correlation was found between the absorption spectrum of the matrix and the MALDI response.

Animals↗

PubMed1997

Assignment of the human gene for KBF2/RBP-Jk to chromosome 9p12-13 and 9q13 by fluorescence in situ hybridization.

The transcription factor KBF2 has been characterized as a factor that binds to the NFkB site of mouse major histocompatibility complex (MHC) class I genes and its amino acid sequence has been shwn to be identical to those of members of the recombination signal-sequence binding protein (RBP-Jk) family. Previous studies by Amakawa et al. (Genomics 17, 306-315, 1993) demonstrated that the functional gene is localized at human chromosome 3q25. However, in the present study we showed by in situ hybridization with the functional KBF2/RBPJk cosmid clone that the gene is localized at 9p12-13 and 9q13, namely, at the same loci as pseudogenes that were reported previously (Zhang et al, Jpn J Human Genet 39, 391-401, 1994).

Animals↗