Cloning and sequencing of dog cDNA encoding the T-cell costimulatory molecule (CTLA-4).
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Abatacept↗
Biomedical subjects
Z Ma
Publications and source records attributed to Z Ma.
Electrospray ionization mass spectrometric analyses of changes in tissue phospholipid molecular species during the evolution of hyperlipidemia and hyperglycemia in Zucker diabetic fatty rats.
The Zucker diabetic fatty (ZDF) rat is a genetic model of type II diabetes mellitus in which males homozygous for nonfunctional leptin receptors (fa/fa) develop obesity, hyperlipidemia, and hyperglycemia, but rats homozygous for normal receptors (+/+) remain lean and normoglycemic. Insulin resistance develops in young fa/fa rats and is followed by evolution of an insulin secretory defect that triggers hyperglycemia. Because insulin secretion and insulin sensitivity are affected by membrane phospholipid fatty acid composition, we have determined whether metabolic abnormalities in fa/fa rats are associated with changes in tissue phospholipids. Electrospray ionization mass spectrometric analyses of glycerophosphocholine (GPC) and glycerophosphoethanolamine (GPE) molecular species from tissues of prediabetic (6 wk of age) and overtly diabetic (12 wk) fa/fa rats and from +/+ rats of the same ages indicate that arachidonate-containing species from heart, aorta, and liver of prediabetic fa/fa rats made a smaller contribution to GPC total ion current than was the case for +/+ rats. There was a correspondingly larger contribution from species with sn-2 oleate or linoleate substituents in fa/fa heart and aorta. The relative contributions of arachidonate-containing GPC species increased in these tissues as fa/fa rats aged and were equal to or greater than those for +/+ rats by 12 wk. For heart and aorta, relative contributions from GPE species with sn-2 arachidonate or docosahexaenoate substituents to the total ion current increased and those from species with sn-2 oleate or linoleate substituents fell as fa/fa rats aged, but these tissue lipid profiles changed little with age in +/+ rats. GPC and GPE profiles for brain, kidney, sciatic nerve, and red blood cells were similar among fa/fa and +/+ rats at 6 and 12 wk of age, and pancreatic islets from fa/fa and +/+ rats exhibited similar GPC and GPE profiles at 12 wk of age. Under-representation of arachidonate-containing GPC and GPE species in some fa/fa rat tissues at 6 wk could contribute to insulin resistance, but depletion of islet arachidonate-containing GPC and GPE species is unlikely to explain the evolution of the insulin secretory defect that is well-developed by 12 wk of age.
Age Factors↗
Contribution of nitric oxide to the pathogenesis of cirrhotic cardiomyopathy in bile duct-ligated rats.
BACKGROUND & AIMS: Decreased cardiac contractility and beta-adrenergic responsiveness have been observed in cirrhosis, but the etiology remains unclear. We aimed to test the role of nitric oxide (NO), a negative inotropic agent, in the pathogenesis of cirrhotic cardiomyopathy in a rat model. METHODS: Cirrhosis was induced by bile duct ligation. Four weeks after ligation or sham operation, cardiac levels of tumor necrosis factor (TNF)-alpha, guanosine 3,5'-cyclic monophosphate (cGMP), inducible NOS (NOS2), and endothelial constitutive NOS (NOS3) messenger RNA (mRNA) and protein were determined. Serum nitrite/nitrate level was measured. Cardiac contractile function was evaluated in isolated left ventricular papillary muscles in the absence and presence of the NOS inhibitor nitro-L-arginine methyl ester (L-NAME). RESULTS: Cardiac TNF-alpha, NOS2 mRNA and protein, cGMP, and serum interleukin (IL)-1beta and nitrite/nitrate levels were significantly higher in cirrhotic rats than sham controls. No significant differences in NOS3 mRNA or protein were found between cirrhotic and sham control rats. Baseline isoproterenol-stimulated papillary muscle contractile force was significantly lower in the cirrhotic group; with L-NAME incubation, contractile force increased significantly in cirrhotic rats but was unaffected in the controls. In normal papillary muscles, IL-1beta attenuated the contractility, but coincubation with L-NAME again reversed this attenuation. Incubation with the exogenous NO donor S-nitroso-N-acetyl-penicillamine also blunted papillary muscle contractility. CONCLUSIONS: These results suggest that cytokine-induced stimulation of NOS2 plays a significant role in the pathogenesis of cirrhotic cardiomyopathy.
Animals↗
Cloning and sequencing of canine MAGE cDNA.
Melanoma antigens (MAGE) are regarded to induce tumour-specific immune response and thought to be potential therapeutical agents for cancer immunotherapy. We hereby report the canine MAGE cDNA cloned from the testis of a beagle dog. Canine MAGE cDNA is 1,455 base pair (bp) nucleotides in length, and contains an open reading frame (ORF) of 1,137 bp nucleotides encoding a protein of 378 amino acids. The predicted amino acid sequence has 22-49% of homology with other MAGE proteins. mRNA transcripts of canine MAGE were detected only in the melanoma and testis and not in other normal tissues of adult dog by reverse transcriptase-polymerase chain reaction (RT-PCR), indicating that the expression pattern of canine MAGE mRNA is similar to that of the MAGE family genes in tumor and normal tissues.
Animals↗
Plasminogen activator inhibitor-1 fused with erythropoietin (EPO) mimetic peptide (EMP) enhances the EPO activity of EMP.
Erythropoietin (EPO) mimetic peptide (EMP) encoding sequence was inserted into the gene of plasminogen activator inhibitor-1 (PAI-1) between Ala348 and Pro349 (P2'-P3'), generating a novel gene, PAI-1/EMP (PMP). This was cloned into pET32a expression vector, fused with TrxA peptide in the vector, and a 63-kDa protein was expressed in inclusion bodies with an expression level >50%. The TrxA/PMP protein was purified by Ni-NTA-agarose metal-ligand affinity chromatography to a purity >90%, showing a single, silver-stained band on SDS-PAGE. Using a reticulocyte counting assay, the EPO activity of PMP was determined to be 5,000 IU/mg, 2,500-fold that of EMP.
Amino Acid Sequence↗
Dynamic and consequential consistency of choices between paths of decision trees.
The generally prescribed procedure for choosing a decision strategy from a decision tree employs a backward induction analysis that entails 3 fundamental consistency principles: dynamic, consequential, and strategic. The first requires the decision maker to follow through on plans to the end, the second requires the decision maker to focus solely on future events and final consequences given the current state of events, and the third is the conjunction of the first 2. Five experiments were reported to test these principles using different subject populations, different procedures for estimating consistency, and different factors for manipulating the attractiveness of the gamble at the final stage of the tree. The main findings were that strategic and dynamic consistency principles were violated at rates that exceeded choice inconsistency.
Adolescent↗
Amyloid in human islets of Langerhans: immunologic evidence that islet amyloid polypeptide is modified in amyloidogenesis.
Amyloid derived from the beta-cell product islet amyloid polypeptide (IAPP) has been implicated for a beta-cell lesion in Type II diabetes mellitus. The pathogenesis of islet amyloid is poorly understood, and in addition to an amyloidogenic IAPP molecule and possibly increased concentration of IAPP, other unknown factors seem to be included. It was shown previously that polyclonal rabbit IAPP antisera label beta cells close to amyloid only weakly. Whether this lack of immunoreactivity depends on lack of IAPP or on hidden epitopes is in question. In the present study, we show that the IAPP immunoreactivity of these beta cells is possible to retrieve. On the other hand, the monoclonal IAPP antibody 4A5, which labels IAPP in beta cells, does not label IAPP in its native amyloid form. We show evidence that this lack of immunoreactivity is not dependent on conformational change of the IAPP molecules in the amyloidogenesis but is likely owing to glycation of IAPP in human islet amyloid deposits.
Amyloid↗
Molecular genotyping of human Ureaplasma species based on multiple-banded antigen (MBA) gene sequences.
Ureaplasma urealyticum has been divided into 14 serovars. Recently, subdivision of U. urealyticum into two species has been proposed: U. parvum (previously U. urealyticum parvo biovar), comprising four serovars (1, 3, 6, 14) and U. urealyticum (previously U. urealyticum T-960 biovar), 10 serovars (2, 4, 5, 7-13). The multiple-banded antigen (MBA) genes of these species contain both species and serovar/subtype specific sequences. Based on whole sequences of the 5'-ends of MBA genes of U. parvum serovars and partial sequences of the 5'-ends of MBA genes of U. urealyticum serovars, we previously divided each of these species into three MBA genotypes. To further elucidate the relationships between serovars, we sequenced the whole 5'-ends of MBA genes of all 10 U. urealyticum serovars and partial repetitive regions of these genes from all serovars of U. parvum and U. urealyticum. For the first time, all four serovars of U. parvum were clearly differentiated from each other. In addition, the 10 serovars of U. urealyticum were divided into five MBA genotypes, as follows: MBA genotype A comprises serovars 2, 5, 8; MBA genotype B, serovar 10 only; MBA genotype C, serovars 4, 12, 13; MBA genotype D, serovar 9 only; and MBA genotype E comprises serovars 7 and 11. There were no sequence differences between members within each MBA genotype. Further work is required to identify other genes or other regions of the MBA genes that may be used to differentiate U. urealyticum serovars within MBA genotypes A, C and E. A better understanding of the molecular basis of serotype differentiation will help to improve subtyping methods for use in studies of the pathogenesis and epidemiology of these organisms.
Amino Acid Sequence↗
Studies of the novel ketolide ABT-773: transport, binding to ribosomes, and inhibition of protein synthesis in Streptococcus pneumoniae.
Macrolide resistance in Streptococcus pneumoniae has been associated with two main mechanisms: target modification by Erm methyltransferases and efflux by macrolide pumps. The ketolide ABT-773, which has a 3-keto group and no L-cladinose sugar, represents a new class of drugs with in vitro activity against a variety of resistant bacteria. Several approaches were undertaken to understand how ABT-773 was able to defeat resistance mechanisms. We demonstrated tighter ribosome binding of ABT-773 than erythromycin. We also showed that ABT-773 (i) accumulated in macrolide-sensitive S. pneumoniae at a higher rate than erythromycin, (ii) was able to bind with methylated ribosomes, though at lower affinities than with wild-type ribosomes, and (iii) accumulated in S. pneumoniae strains with the efflux-resistant phenotype.
Anti-Bacterial Agents↗
Species identification and subtyping of Ureaplasma parvum and Ureaplasma urealyticum using PCR-based assays.
There is good evidence that the organism currently known as Ureaplasma urealyticum should be divided into two species-U. parvum (previously U. urealyticum biovar 1) and U. urealyticum (previously U. urealyticum biovar 2). In this study, we designed a series of primers, targeting the 16S rRNA gene and 16S rRNA-23S rRNA intergenic spacer regions, the urease gene subunits, and the 5' ends of the multiple-banded antigen (MBA) genes, to identify and subtype these Ureaplasma species. All of the species-specific primer pairs could distinguish the two species, but only subtype-specific primer pairs targeting the MBA genes could distinguish subtypes within each species. U. parvum was separated into three subtypes, represented by serovars 1, 3/14, and 6. U. urealyticum was also separated into three subtypes by PCR and/or direct sequencing. Subtype 1 consisted of serovars 2, 5, 8, and 9; subtype 2 contained serovars 4, 10, 12, and 13; and subtype 3 contained serovars 7 and 11. A selection of primer pairs was used to identify and subtype 78 clinical ureaplasma isolates from vaginal swabs of pregnant women and to identify and subtype ureaplasmas directly in 185 vaginal swabs in which they had been previously detected. U. parvum was identified in 228 (87%) of 263 isolates or specimens, and U. urealyticum was identified in 50 (19%) (both were present in 6%). Serovars 3/14 (48%) and 1 (43%) were most common among U. parvum isolates, and subtypes 2 (62%) and 1 (34%) were most common among U. urealyticum isolates. This new PCR-based typing system will facilitate future studies of the relationship between individual Ureaplasma species or subtypes and human disease.
Antigens, Bacterial↗
Preparation of biodegradable microspheres of testosterone with poly(D,L-lactide-co-glycolide) and test of drug release in vitro.
Biodegradable microspheres formulation of testosterone (T) can be used as a new physiological approach for androgen replacement in hypogonadal men. In this study, poly(D,L-lactide-co-glycolide) (PLGA) microspheres containing T were prepared by a solvent-evaporation/solvent-diffusion process and the drug release tests of the microspheres were carried out in vitro. T/PLGA microspheres with good yield, desired size and satisfied drug loading were obtained. A significant testosterone sustained release was shown in the drug release tests in vitro. Since PLGA microspheres preparations are normally sterilized by colbat-60 irradiation, the effects of 25 kGy colbat-60 irradiation on physicochemical properties and in vitro drug release profile of T/PLGA microsphere were investigated. The results showed that the irradiation didn't have any effects on the physicochemical properties of T. Though about one-third decrease in molecular weight of PLGA was caused by the irradiation, no significant changes were observed on the drug release profile in vitro.
Biodegradation, Environmental↗
[Effect of anti-endotoxin therapy on vaso-active substances in decompensated liver cirrhosis].
OBJECTIVE: To study the anti-endotoxin therapy on the plasma levels of nitric oxide, prostacyclin, tumor necrosis factor-alpha in patients with liver cirrhosis after hepatitis. METHODS: Thirty patients with decompensated liver cirrhosis accepted anti-endotoxin therapy with oral Amoxycillin and Smedta for 2 weeks. Plasma levels of endotoxin, nitric oxide, prostacyclin and tumor necrosis factor-alpha were detected before and after therapy in study group and control group, respectively. The relationship between endotoxin and vasoactive substances and between the four substances and the status of patients were analyzed. RESULTS: The four substances were all increased significantly (P<0.01) in patients with liver cirrhosis compared with control group and decreased obviously after treatment for 2 weeks (endotoxin from 0.546X10(21) U/L to 0. 347X10(21) U/L, no from 56.498 mumol/L to 31.256 mumol/L, 6-keto-PGF1 alpha from 716.964 ng/L to 539.867ng/L, and TNF-alpha from 3.090 mug/L to 1.750 mug/L (P<0.01). CONCLUSION: The plasma levels of nitric oxide, prostacyclin and tumor necrosis factor-alpha increased because of endotoxemia. Amoxycillin and Smecta can clear endotoxin out effectively.
Adult↗
Differential diagnosis between hepatic focal nodular hyperplasia and hepatocellular carcinoma with negative alhpa-fetoprotein.
OBJECTIVE: To study the differential diagnosis between hepatic focal nodular hyperplasia (FNH) and hepatocellular carcinoma (HCC) with negative alpha-feto protein. METHODS: To analyse retrospectively the clinical and imaging materials of 18 patients with FNH and 254 patients with AFP negative HCC proven by operation and pathology during March 1996 to March 1999 in our institute. RESULTS: Patients with FNH were largely younger (66.7% under 40 years), discovered accidentally (66.7%), and without hepatitis background (83.3%). Majority of them had a normal liver function (72.0%). A big central artery was found in the lesion with high velocity and low resistant index in 71.4% of patients by color Doppler ultrasound. CT scan showed transient immediate enhancement in 85.7% of patients after bolus injection, being homogeneous (53.3%) and isodensity (73.3%) in the portal vein phase. MR imaging demonstrated early vigorous enhancement (83.3%) and homogenous (66.7%) lesion. In contrast, patients with AFP negative HCC were generally older (85.8% over 40 years), with symptoms (74.0%). A color flow with high velocity and high resistant index was found by color Doppler ultrasound. CT scan showed early heterogenous enhancement (96.6%) after bolus injection and being hypodensity in portal vein phase. MR imaging indicated early heterogeneous enhancement (91.7%). CONCLUSION: FNH shows some typical clinical and imaging features. Therefore, it is feasible to be differentiated from HCC with negative AFP in some of the patients.
Adolescent↗
Differential effect of local infusion of serotonin reuptake inhibitors in the raphe versus forebrain and the role of depolarization-induced release in increased extracellular serotonin.
Systemic administration of selective serotonin reuptake inhibitors (SSRIs) elicits larger increases in serotonin (5-HT) in raphe than in forebrain sites. Because serotonergic neuronal activity is suppressed, the mechanism underlying SSRI-induced increases in extracellular 5-HT is unclear. This study determined whether local infusion of SSRIs also elicited regionally selective increases in extracellular 5-HT, and whether changes depended on serotonergic neuronal depolarization. Conventional microdialysis methods were used to measure 5-HT in dorsal raphe (DRN), median raphe, nucleus accumbens (NAcc), and frontal cortex of unanesthetized rats. During infusion of SSRIs into each site, the maximum response was an approximately 6- to 7-fold increase in 5-HT in NAcc and frontal cortex, and an approximately 20-fold increase in DRN and median raphe. The larger increase in 5-HT in raphe was confirmed using zero-net-flux microdialysis. In NAcc, baseline 5-HT was 0.7 nM, and levels increased to a maximum of 3.1 nM during infusion of the SSRI citalopram. Baseline 5-HT in DRN was greater, 1.3 nM, and increased to 12.4 nM in response to citalopram. Consistent with evidence that autoreceptor activation inhibits serotonergic neuronal discharge, SSRI infusion into DRN produced a moderate decrease in 5-HT in NAcc. However, increases in 5-HT in DRN elicited by SSRI infusion were attenuated by 8-hydroxydipropylaminotetralin and tetrodotoxin. These data indicate that depolarization-dependent 5-HT release was not fully inhibited during SSRI infusion into DRN. In summary, SSRIs produce larger increases in extracellular 5-HT in raphe than in forebrain sites. Increases depend in part on depolarization-induced release, which may be greater in raphe than in forebrain.
8-Hydroxy-2-(di-n-propylamino)tetralin↗
[Research on renaturation of recombinant human pro-urokinase expressed from Escherichia coli].
Recombinant human pro-urokinase forms insoluble inclusion body when overexpressed in Escherichia coli, and it must be denatured and renatured in vitro before it acquires activity. This study aimed to increase the renaturation yield of denatured pro-urokinase. We have evaluated the basic renaturation conditions of pro-urokinase through qualitative and quantitative analysis of pH, temperature, denaturant concentration, protein concentration, the ratio of reduced and oxidized thiol reagents. The effects of nonspecific additives, step-wise dilution and urea gradient dialysis have been also compared. The optimal conditions of pro-urokinase renaturation with the yield about 20%-30% have been obtained.
Dithiothreitol↗
[Cloning of taxadiene synthase cDNA from the cell line of Taxus cuspidata].
Taxadiene synthase plays an important role in taxol biosynthesis. RT-PCR was used for cloning taxadiene synthase cDNA fragment from the cells of T. cuspidata. The cDNA was cloned into vector pGEM and transformed to E. coli J M109. The cloned cDNA named pCBMZ was further confirmed by Southern blotting assay and was sequenced. The result showed that taxadiene synthase cDNA of Taxus cuspidata was highly homologous with that of Taxus brevifolia.
Base Sequence↗
Variations in dose from diagnostic radiographic examinations in Los Angeles County.
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Calibration↗
[A comparative study on nutrient accumulation and distribution of different generations of Chinese fir plantations].
The nutrient accumulations and distribution of different generation of Chinese fir plantations in central production areas of China were studied through the investigation of plantation with different generation(first, second and third), ages (5, 10, 15, 20 years old) and sites(site index 14, 16 and 18). The nutrient accumulations and distribution of Chinese fir plantations were greatly influenced by the number of planting generation. Nutrient accumulation and utilization efficiency in tree layer of Chinese fir plantations declined with the increasing planting generation number, with the first generation > the second > the third; while the nutrient accumulation of understory vegetation was increased with the increasing of planting generation number. Compared with the first generation plantations, nutrient accumulation of tree layer of the second and the third generations decreased by 17.56% and 36.24% respectively, and the third generation platation decreased by 22.65% than the second generation. Meanwhile, successive planting resulted in a decreasing nutrient utilization efficiency of Chinese fir plantation, and an increasing nutrient necessary for dry matter production per unit, which is disadvantageous to the maintaining of soil fertility, but beneficial to the nutrient accumulation of understory vegetation.
Abies↗