Biomedical subjects

Z Lu

Publications and source records attributed to Z Lu.

At least 271 records · Page 15Linked to original sources

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

[Report of 18 cases lymphoblastic lymphoma].

OBJECTIVE: To identify the clinical, pathological, and immunological characteristics of lymphoblastic lymphoma (LBL). METHODS: The relation of clinical features, cellular morphology and immuno-phenotypes to the treatment outcome and prognosis was analyzed in 18 LBL patients. RESULTS: The patients were 15 males and 3 females with a median age of 27 years. Fourteen cases showed bone marrow infiltration, 10 lymphoma leukemia and 9 mediastinal tumor. Fifteen cases were of convoluted cell type expressed T cell marker, three patients were of B-cell type and all achieved complete remission. The 5 year survival rate of the 18 cases was 11.2% with a median survival duration of 10.1 months. CONCLUSION: LBL was found predominantly in male with a younger onset age, and was characterized by involvement of bone marrow and mediastina. The majority of LBL patients were of convoluted cell type expressed T cell marker. The patients showed poor response to therapy, while B-cell type showed a better prognosis than T-cell type.

Adolescent↗

PubMed1998

[Psammomatoid ossifying fibroma].

OBJECTIVE: To clarify the histopathological, clinical behavior biological characterics and the relationship among the psammomatoid ossifying fibroma (POF), ossifying fibroma and fibrous dysplasia of bone. METHODS: Thirty-one cases of POF in the ear and sinonasal region were studied retrospectively. The sections, clinicopathological records from June, 1956 to November, 1996 were reviewed. The reticulum fiber and Masson's stain and alkaline phosphatase immunostain were done in 10 cases, Vimentin, Desmin, EMA and smooth actin immunohistochemical stain were done in 5 cases. One case was studied by transmission electron microscope. RESULTS: The specimens were broken tissue with the sand-like felling, eleven specimens with intact thin shell consisted of bone tissue were used to study the changes in the area between tumor and normal bone. Histopathologically they were rich in mesenchymal tumor cells and a lot of calcifying psammomatoid-like osteoid and a few of calcified bodies similar to those described by Shafer, and the bony trabecula was not found in the center of the tumor. In addition, three zones were noted at the junction of normal bone and tumor, namely, the normal bone-reactive proliferative bone-tumor. In some cases, the reactive bony proliferation may be not marked. The normal bone adjacent to the tumor may be absorbed and disappeared, and were then replaced by the tumor, and finally led to tumor tissue invasion into the soft tissue, but the infiltration appearance is not present. CONCLUSION: POF is the slowly growing benign tumor and is different from ossifying fibroma and fibrous dysplasia of bone.

Adolescent↗

PubMed1998

[Verification of a new processing technology for pilot production of Aconitum coreanum (Lévl.) Raipaics].

The stability and feasibility of a new technology for processing Aconitum coreanum have been tested for pilot production by determining the components, toxicity(LD50) and traditional identification standard. The result shows that the contents of guanfu A and total alkaloid between the small trial and pilot production are slightly different and LD50 are nearly similar. Hypaconitine was not found in all kinds of processed products. The new technology has thus been proved stable and feasible.

Alkaloids↗

PubMed1998

[Gene expression of fibrous main collagen in the lumbar disc].

OBJECTIVE: To study the patterns of gene expression of main collagen, type I and type II in lumbar discs. METHODS: The level of collagen gene mRNA expression of type I and type II was investigated by in situ hybridization on fetal, adults and pathologic specimens with cDNA probe. Collagen in various specimens was observed by staining of sirius scarlet. RESULTS: Positive mRNA hybridization signals of collagen type I were concentrated around outlayer of annulus fibrosus. Type II collagen was highly expressed in nucleus pulposus. In adult and pathologic specimens, no hybridization signal of type II collagen was observed, and the expression level of type II collagen mRNA decreased. Positive signals appeared in nucleus pulposus. CONCLUSION: Obvious changes took place in the regulation of collagen gene expression with aging. Expression of collagen in adult and pathological disc was decreased. Abnormal appearance could be seen between collagen gene type I and type II. Expression of collagen type I mRNA appeared in nucleus pulposus.

Collagen↗

PubMed1998

Reversion of multidrug resistance in the P-glycoprotein positive breast cancer cell line (MCF-7/ADR) by introduction of hammerhead ribozyme.

A hammerhead ribozyme which site-specifically cleaved the GUC position in codon 880 of the mdr1 mRNA was designed. The target site was chosen between the two ATP binding sites, which may be important for the function of the P-Gp as an ATP-dependent pump. A DNA sequence encoding the ribozyme gene was then incorporated into a eukaryotic expression vector (pH beta Apr-1 neo) and transfected into the breast cancer cell line MCF-7/Adr, which is resistant to adriamycin and expresses the MDR phenotype. The ribozyme was stably expressed in the cell line by the RNA dot blotting assay. The result of Northern blot assay showed that the expressed ribozyme could decrease the level of mdr1 mRNA expression by 83.5%; and the expressed ribozyme could inhibit the formation of P-glycoprotein detected by immuno-cytochemistry assay and could reduce the cell's resistance to adriamycin; this means that the resistant cells were 1,000-fold more resistant than the parental cell line (MCF-7), whereas those cell clones that showed ribozyme expression were only 6-fold more resistant than the parental cell line. These results show that a potentially useful tool is at hand which may inactivate MDR1 mRNA and revert the multidrug resistance phenotype.

ATP Binding Cassette Transporter, Subfamily B, Mem↗

PubMed1998

[The preliminary analysis of domestic hydrogel microspheres for endovascular embolization].

OBJECTIVE: To evaluate the embolic effects and biocompatibility of domestic hydrogel microspheres (HMs). METHOD: 22 domestic rabbits were used. 0.03 g/2ml, 0.06 g/2ml domestic Hms of 70 - 150 microm and 2 ml normal saline were injected respectively through catheterization in the right common carotid arteries of rabbits. The changes in neurologic functions, general state and average weight of rabbits were observed, and the histomorphological changes of embolized arteries and surrounding tissues were evaluated by analysis of macroscopy and light microscope. RESULT: Rabbits' neurologic symptoms (hemiparalysis, convulsion and hypotonia) and death were observed after embolization. Thrombogenesis was present and the entire cross sections of blood vessels could easily be embolized. Neither acute and chronic inflammatory cells nor remarkable general toxic and side effects were shown in rabbits. CONCLUSION: Domestic HMs can effectively block the vessels, and they have the characteristics of good biocompatibility. The kind of domestic HMs is a promising particulate embolic agent in clinical sets.

Animals↗

PubMed1998

Decreased dihydropyrimidine dehydrogenase activity in a population of patients with breast cancer: implication for 5-fluorouracil-based chemotherapy.

Dihydropyrimidine dehydrogenase (DPD) is the initial, rate-limiting enzyme in the catabolism of 5-fluorouracil (5-FU), one of the most widely used chemotherapeutic agents in the treatment of breast cancer. The objective of this study was to determine the population characteristics of DPD activity in patients with breast cancer as well as the frequency of DPD deficiency in this population. DPD activity in peripheral blood mononuclear cells (PBM-DPD) was determined in 360 patients with breast cancer, with the mean PBM-DPD (0.26 +/- 0.01 nmol/min/mg protein) being significantly lower than that observed in female controls (0.44 +/- 0.02 nmol/min/mg protein; P < 0.01). ANOVA analysis examining the significance of differences in DPD activity among various groups indicated that only disease difference (breast cancer versus normal subjects) was significant after adjustments for race and age. In the present study, 21 (5.8%) patients were considered to be DPD deficient, indicating that this pharmacogenetic syndrome may be more common than anticipated (no DPD-deficient individual was found in the controls). Significantly lower DPD activity in patients with breast cancer may predispose to 5-FU-associated toxicity. These results provide further rationale for individualizing the 5-FU dose, thus reducing the risk of toxicity and/or improving therapeutic efficacy in patients with breast cancer.

Adult↗

PubMed1998

Optimization of parameters for isolation of protoplasts from Gracilaria verrucosa (Rhodophyta).

A systematic method was designed for the isolation of a large number of protoplasts from an agarophyte alga Gracilaria verrucosa using agarase from a marine bacterium Vibrio sp. PO-303 and commercial enzymes (Cellulase Onozuka RS and Macerozyme R-10). Pretreatment of the tissue with 5% papain at 22 degreesC for 30 min before digestion with polysaccharide-degrading enzymes increased the protoplast yield. Suitable pH and temperature for the polysaccharide-degrading enzyme reaction were 6.5 and 22 degreesC, respectively. Mannitol (0.7 M) was found to be an excellent osmotic stabilizer. When the tissue (1 g, fresh wt.) of G. verrucosa pretreated with 5% papain solution (20 mM MES buffer, pH 7.5, containing 0.7 M mannitol) was digested with an enzyme mixture consisting of 4 units of agarase, 4% Cellulase Onozuka, 2% Macerozyme, and 0.7 M mannitol in 20 mM MES buffer (pH 6.5) with gentle agitation for 150 min at 22 degreesC, 1.03 x 10(8) protoplasts were obtained.

Journal Article↗

PubMed1998

Purification and characterization of agarases from a marine bacterium, Vibrio sp. PO-303.

A marine bacterium, Vibrio sp. PO-303, produced three kinds of extracellular agarases. These enzymes were purified to homogeneity by ammonium sulfate precipitation and successive column chromatographies. The molecular masses of agarase-a, -b, and -c were estimated to be 87.5, 115, and 57 kDa by SDS-PAGE with isoelectric point of 6.6, 3.4, and 8.4, respectively. These enzymes had maximal activity at pH 6.5-7.5 and at around 38-55 degreesC. They differed in their sequences at the amino termini of the protein chains. All enzymes were inhibited completely by Hg2+. Ag+, Cu2+, and Zn2+ strongly inhibited agarase-a and -c compared with agarase-b, and the activity of agarase-c fell wide by Al3+, Fe3+, and EDTA. Agarase-a hydrolyzed agarose to give neoagarotetraose and -hexaose as predominant products, but could not cleave neoagarotetraose. The main hydrolysis products of agarase-b were neoagarobiose from agarose and neoagarooligosaccharides more than dimer. Agarase-c could not cleave neoagarohexaose.

Journal Article↗

PubMed1997

Development of an epithelium-specific expression cassette with human DNA regulatory elements for transgene expression in lung airways.

The efficient expression of therapeutic genes in target cells or tissues is an important component of efficient and safe gene therapy. Utilizing regulatory elements from the human cytokeratin 18 (K18) gene, including 5' genomic sequences and one of its introns, we have developed a novel expression cassette that can efficiently express reporter genes, as well as the human cystic fibrosis transmembrane conductance regulator (CFTR) gene, in cultured lung epithelial cells. CFTR transcripts expressed from the native K18 enhancer/promoter include two alternative splicing products, due to the activation of two cryptic splice sites in the CFTR coding region. Modification of the K18 intron and CFTR cDNA sequences eliminated the cryptic splice sites without changing the CFTR amino acid sequence, and led to enhanced CFTR mRNA and protein expression as well as biological function. Transgenic expression analysis in mice showed that the modified expression cassette can direct efficient and epithelium-specific expression of the Escherichia coli LacZ gene in the airways of fetal lungs, with no detectable expression in lung fibroblasts or endothelial cells. This is the first expression cassette which selectively directs lung transgene expression for CFTR gene therapy to airway epithelia.

Animals↗

PubMed1997

Identification of a new mouse beta-chemokine, thymus-derived chemotactic agent 4, with activity on T lymphocytes and mesangial cells.

Thymus-derived chemotactic agent 4 (TCA4), a new member of the beta-chemokine family, was cloned from a mouse thymic cDNA library. High levels of TCA4 mRNA are expressed in thymus; lower levels of message are found in spleen, heart, and kidney. Anti-TCA4 antibodies were used to localize sites of TCA4 expression within lymphoid tissues. In the thymus, UEA-1+ medullary epithelial cells, some endothelial cells, and additional undefined stromal elements were stained with anti-TCA4. TCA4 was also expressed as a meshlike network in splenic white pulp and in the medullary region of the lymph nodes. In addition, some lymph node and splenic blood vessels stained with anti-TCA4 antibodies. Rel B NFkappaB-deficient mice lack a transcription factor required for the generation of dendritic cells and the development of an organized thymic medulla. Rel B-deficient animals express very low levels of TCA4 in the thymus and little or no TCA4 in the periphery. At subnanomolar concentrations, TCA4 is a chemoattractant of mature T cells; the potential role of this novel chemokine in facilitating normal lymphocyte traffic is discussed. TCA4 is also a chemoattractant of cultured mesangial cells. Neutralizing anti-TCA4 mAb was used to demonstrate the specificity of TCA4-mediated cell migration. Finally, competitive binding studies with a SV40-transformed mouse mesangial cell line demonstrated that other murine beta-chemokines (monocyte chemotactic protein-1, macrophage inflammatory protein-1alpha, macrophage inflammatory protein-1beta, and thymus-derived chemotactic agent 3) do not compete for TCA4 binding.

Amino Acid Sequence↗

PubMed1997

Activation of HIV-1 coreceptor (CXCR4) mediates myelosuppression.

Chemokines are cytokines that activate and induce the migration of leukocytes. Stroma-derived factor-1 (SDF-1) is a novel chemokine that blocks the entry of T-tropic HIV-1 mediated by fusin/CXCR4/LESTR (leukocyte-derived seven-transmembrane domain receptor). In this work we demonstrate that SDF-1 triggers increases in intracellular calcium and inhibits the proliferation of myeloid progenitor cell line 32D. By contrast, SDF-1 neither triggers a calcium response nor affects the proliferation of the myeloid progenitor cell line 32D-GR that is deficient in CXCR4. Responsiveness to SDF-1 was rescued by transfection of 32D-GR cells with a cDNA encoding the human CXCR4. The data indicate that SDF-1 induces myelosuppression by activation of CXCR4. The constitutive production of SDF-1 by bone marrow stromal cells argues for a major role of SDF-1 on the regulation of myelopoiesis.

Animals↗

PubMed1997

Analysis of 74 kb of DNA located at the right end of the 330-kb chlorella virus PBCV-1 genome.

This report completes a preliminary analysis of the sequence of the 330,740-bp chlorella virus PBCV-1 genome, the largest virus genome to be sequenced to date. The PBCV-1 genome is 57% the size of the genome from the smallest self-replicating organism, Mycoplasma genitalium. Analysis of 74 kb of newly sequenced DNA, from the right terminus of the PBCV-1 genome, revealed 153 open reading frames (ORFs) of 65 codons or longer. Eighty-five of these ORFs, which are evenly distributed on both strands of the DNA, were considered major ORFs. Fifty-nine of the major ORFs were separated by less than 100 bp. The largest intergenic distance was 729 bp, which occurred between two ORFs located in the 2.2-kb inverted terminal repeat region of the PBCV-1 genome. Twenty-seven of the 85 major ORFs resemble proteins in databases, including the large subunit of ribonucleotide diphosphate reductase, ATP-dependent DNA ligase, type II DNA topoisomerase, a helicase, histidine decarboxylase, dCMP deaminase, dUTP pyrophosphatase, proliferating cell nuclear antigen, a transposase, fungal translation elongation factor 3 (EF-3), UDP glucose dehydrogenase, a protein kinase, and an adenine DNA methyltransferase and its corresponding DNA site-specific endonuclease. Seventeen of the 153 ORFs resembled other PBCV-1 ORFs, suggesting that they represent either gene duplications or gene families.

Chlorella↗

PubMed1997

A conserved African swine fever virus IkappaB homolog, 5EL, is nonessential for growth in vitro and virulence in domestic swine.

An African swine fever virus (ASFV) gene with similarity to the cellular inhibitor of NFkappaB (IkappaB) was described in the pathogenic African isolate Malawi Lil-20/1 (ORF 5EL) and a cell-culture-adapted European virus, BA71V (ORF A238L). Recently, this gene was shown to be a functional IkappaB homolog capable of downregulating NFkappaB-regulated gene expression. This observation suggests the gene may be of significance to aspects of ASFV pathogenesis and virulence in domestic swine by interfering with a normal antiviral host response. Here we show, using nucleotide sequence analysis, that 5EL is highly conserved among various African and European pathogenic field isolates and that in all cases its similarity to IkappaB genes is limited to the presence of four low complexity ankyrin repeats in the ASFV gene. The 5EL gene of Malawi Lil-20/1 encodes a 28-kDa protein which was expressed early in virus-infected macrophage cell cultures with maximum levels observed at 3 to 5 hr postinfection. To study gene function, a Malawi Lil-20/1 5EL gene deletion mutant (Delta5EL) was constructed. Growth characteristics of Delta5EL in porcine macrophage cell cultures were indistinguishable from those of the parental virus. And, Delta5EL exhibited an unaltered parental Malawi Lil-20/1 disease and virulence phenotype in domestic swine. Thus, although highly conserved among ASFV isolates, 5EL is nonessential for growth in porcine macrophages in vitro and for viral virulence in domestic swine. A possible role for this gene in transmission of ASFV in nature, a setting which involves the cycling of ASFV between two highly adapted hosts, Ornithodoros ticks and warthogs or bush pigs, in sub-Saharan Africa is discussed.

African Swine Fever↗

PubMed1997

Molecular analysis of a novel winged helix protein, WIN. Expression pattern, DNA binding property, and alternative splicing within the DNA binding domain.

We have cloned a novel winged helix factor, WIN, from the rat insulinoma cell line, INS-1. Northern blot analysis demonstrated that WIN is highly expressed in a variety of insulinoma cell lines and rat embryonic pancreas and liver. In adults, WIN expression was detected in thymus, testis, lung, and several intestinal regions. We determined the DNA sequences bound in vitro by baculovirus-expressed WIN protein in a polymerase chain reaction-based selection procedure. WIN was found to bind with high affinity to the selected sequence 5'-AGATTGAGTA-3', which is similar to the recently identified HNF-6 binding sequence 5'-DHWATTGAYTWWD-3' (where W = A or T, Y = T or C, H is not G, and D is not C). We have isolated human WIN cDNAs by library screening and 5'-rapid amplification of cDNA ends. Sequence analysis indicates that the carboxyl terminus of human WIN has been previously isolated as a putative phosphorylation substrate, MPM2-reactive phosphoprotein 2 (MPP2); WIN may be regulated by phosphorylation. Alignment of the rat and human WIN cDNAs and their comparison with mouse genomic sequence revealed that the WIN DNA binding domain is encoded by four exons, two of which (exons 4 and 6) are alternatively spliced to generate at least three classes of mRNA transcripts. These transcripts were shown by RNase protection assay to be differentially expressed in different tissues. Alternative splicing within the winged helix DNA binding domain might result in modulation of DNA binding specificity.

Alternative Splicing↗

PubMed1997

Purification, characterization, and synthesis of an inward-rectifier K+ channel inhibitor from scorpion venom.

We have purified a protein inhibitor of an inward-rectifier K+ channel, ROMK1, from the venom of the scorpion Leiurus quinquestriatus var. hebraeus. The inhibitor is Lq2, a previously discovered blocker of voltage- and Ca2+-activated K+ channels. Mutations were made on the channel and the inhibitor, and the resulting effects were examined using an electrophysiological assay. The data show that Lq2 blocks the pore of ROMK1, and that the interaction surface on Lq2 is the same for binding to inward-rectifier, voltage-activated, or Ca2+-activated K+ channels. These findings support the notion that different classes of K+ channels have different gates but a similar K+-selective pore structure.

Amino Acid Sequence↗

PubMed1997

Evolution of HIV-1 coreceptor usage through interactions with distinct CCR5 and CXCR4 domains.

The chemokine receptor CXCR4 functions as a fusion coreceptor for T cell tropic and dual-tropic HIV-1 strains. To identify regions of CXCR4 that are important for coreceptor function, CXCR4-CXCR2 receptor chimeras were tested for the ability to support HIV-1 envelope (env) protein-mediated membrane fusion. Receptor chimeras containing the first and second extracellular loops of CXCR4 supported fusion by T tropic and dual-tropic HIV-1 and HIV-2 strains and binding of a monoclonal antibody to CXCR4, 12G5, that blocks CXCR4-dependent infection by some virus strains. The second extracellular loop of CXCR4 was sufficient to confer coreceptor function to CXCR2 for most virus strains tested but did not support binding of 12G5. Truncation of the CXCR4 cytoplasmic tail or mutation of a conserved DRY motif in the second intracellular loop did not affect coreceptor function, indicating that phosphorylation of the cytoplasmic tail and the DRY motif are not required for coreceptor function. The results implicate the involvement of multiple CXCR4 domains in HIV-1 coreceptor function, especially the second extracellular loop, though the structural requirements for coreceptor function were somewhat variable for different env proteins. Finally, a hybrid receptor in which the amino terminus of CXCR4 was replaced by that of CCR5 was active as a coreceptor for M tropic, T tropic, and dual-tropic env proteins. We propose that dual tropism may evolve in CCR5-restricted HIV-1 strains through acquisition of the ability to utilize the first and second extracellular loops of CXCR4 while retaining the ability to interact with the CCR5 amino-terminal domain.

Cell Fusion↗