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1.
Amelia J. Ahern-Rindell David J. Prieur Robert D. Murnane Srinivasa S. Raghavan Peter F. Daniel Robert H. McCluer Steven U. Walkley Steven M. Parish John M. Opitz James F. Reynolds 《American journal of medical genetics. Part A》1988,31(1):39-56
Histopathologic, ultrastructural and Golgi impregnation studies disclosed lesions characteristic of a neuronal lysosomal storage disease in related sheep with onset of neurologic signs at 4–6 months. Biochemical and enzymatic evaluation disclosed storage of GM1 ganglioside, asialo-GM1, and neutral long chain oligosaccharides in brain, urinary excretion of neutral long chain oligosaccharides, and deficiencies of lysosomal β-galactosidase and α-neuraminidase. Retrospective and limited prospective genetic studies suggested autosomal recessive inheritance. A gene-dosage effect on β-galactosidase levels was documented in fibroblasts from putative heterozygous sheep. Fibroblasts from affected sheep did not have increased β-galactosidase activity after incubation with the protease inhibitor, leupeptin. In some aspects this disease is similar GM1 gangliosidosis, but is unique in that a genetic defect in lysosomal β-galactosidase may cause the deficiency of lysosomal α-neuraminidase. 相似文献
2.
Xiaoping Duan Shu-Fang Jia Zhichao Zhou Robert R. Langley Marcela F. Bolontrade Eugenie S. Kleinerman 《Clinical & experimental metastasis》2005,21(8):747-753
Introduction. Expression of adhesion molecules such as α
v
β
3 integrin has been associated with the metastatic potential of tumor cells. The purpose of this study was to determine whether α
v
β
3 expression correlated with the metastatic potential of human osteosarcoma cells. Materials and methods. We developed a series of sublines (LM2–LM7) from human osteosarcoma SAOS parental cells, with progressively increasing potential to form lung metastases in nude mice after intravenous injection. SAOS parental and LM2 cells were poorly metastatic, but LM7 cells resulted in visible metastatic lung nodules by 6–8 weeks. We quantified α
v
β
3 integrin expression using flow cytometry. Results. α
v
β
3 expression correlated with the metastatic potential of the cells, with LM7 cells showing the highest expression. LM7 cell adhesion to vitronectin decreased after treatment with echistatin, a RGD-containing peptide antagonist of α
v
β
3. LM7 cells demonstrated higher chemotactic activity than SAOS cells to a homogenate made from lung tissue. This chemotactic activity was also inhibited by echistatin. These data indicated that α
v
β
3 was critical for the migration of LM7 cells to the lung homogenate. Chemotaxis to a liver homogenate was the same for LM7 and SAOS cells. Migration of LM7 cells through lung endothelial cells was higher than that through liver endothelial cells, and echistatin again inhibited this migration. Conclusions. α
v
β
3 integrin expression may play a role in the metastatic potential of osteosarcoma cells by enhancing the ability of the cells to migrate specifically to the lung. α
v
β
3 integrin may therefore be a potential new target for osteosarcoma.This revised version was published online in August 2005 with a corrected cover date. 相似文献
3.
JungHwa Lee Natalia Novoradovskaya Barbara Rundquist Jeffery Redwine Cesare Saltini Mark Brantly 《Molecular genetics and metabolism》1998,63(4):270-280
α1-Antitrypsin (α1AT) provides the major protection in the lung against neutrophil elastase-mediated proteolysis. Inheritance of α1AT deficiency alleles is associated with an increased risk of emphysema and liver disease. α1AT null alleles cause the total absence of serum α1AT and represent the ultimate in a continuum of alleles associated with α1AT deficiency. The molecular mechanisms responsible for absence of serum α1AT include splicing abnormalities, deletion of α1AT coding exons, and premature stop codons. We identified an Italian individual with asthma, emphysema, and a very low level of serum α1AT. DNA sequencing demonstrated theMprocidadeficiency allele and a novel null allele,QOtrastevere(c654 G → A, W194Z), a nonsense mutation near the intron 2 (IVS2) splice acceptor site. To determine the molecular basis ofQOtrastevereand specifically to evaluate whether this nonsense mutation interfered with mRNA processing by altered splicing, we used a Chinese hamster ovary cell line permanently transfected withQOtrastevereor normal M α1AT with and without IVS2. Northern blot analysis demonstrated that the normal M construct, with or without IVS2, expressed α1AT mRNA of a similar size. The nonsense mutation was associated with moderately reduced α1AT mRNA regardless of the presence or absence of IVS2. Reduction in α1AT mRNA regardless of the opportunity for splicing supports a translational-translocation model as the cause of reduced α1AT mRNA rather than the nuclear scanning model. Pulse–chase studies followed by immunoprecipitation demonstrated an endoplasmic reticulum-retained 31 kDaQOtrastevereα1AT, which was rapidly degraded. Although mRNA content was moderately reduced, retention and rapid intracellular degradation of the truncated form are the major mechanisms for the absence of secreted α1AT. 相似文献
4.
Makoto Hoshino MD JaeJoon Sim MD Kunihiko Shimizu MD Hiroyuki Nakayama MD Ai Koya MD 《The Journal of allergy and clinical immunology》1999,103(6):1054
Background: Asthma is a chronic inflammatory disease of the airways. The chemokines are potent chemoattractants for eosinophils and other types of cells associated with allergic inflammation. AA-2414, a new thromboxane A2 receptor antagonist, reduces bronchial hyperresponsiveness in asthmatic subjects, but its mechanism of action is unclear. Objective: We tested the hypothesis that the beneficial effects of AA-2414 in asthma result from reduction in the number of inflammatory cells infiltrating the airway associated with inhibition of chemokine release. Methods: We studied bronchial biopsy specimens from 31 asthmatic subjects before and after oral treatment with AA-2414 (80 mg/day) or matched placebo for 4 months in a double-blind manner. Biopsy specimens were examined by immunohistochemistry. Each subject recorded symptom score and peak expiratory flow (PEF). Lung function and bronchial responsiveness to methacholine were measured before and after treatment. Results: After treatment, significant improvements in symptom score (P < .05), PEF (P < .01), diurnal variation of PEF (P < .01), and bronchial responsiveness (P < .01) were observed in the AA-2414 group compared with the placebo group. These improvements were accompanied by a significant decrease in the number of submucosal EG2+ eosinophils (P < .05). There was also a reduction in the number of cells expressing RANTES (P < .05) and macrophage inflammatory protein (MIP)-1α (P < .05) in the epithelium and of cells expressing monocyte chemotactic protein-3 (P < .01), RANTES (P < .05), MIP-1α (P < .01), and eotaxin (P < .01) in the submucosa in the AA-2414 treatment group. A significant correlation was found between the number of EG2+ eosinophils and numbers of monocyte chemotactic protein-3+ (rs = 0.52, P < .005), MIP-1α+ (rs = 0.34, P < .05), and eotaxin+ cells (rs = 0.47, P < .01) in the submucosa. There was a significant negative correlation between the increase in bronchial responsiveness and the change in number of submucosal EG2+ cells (rs = –0.65, P < .001). Conclusions: These findings suggest that AA-2414 treatment of patients with asthma may inhibit activated eosinophil infiltration in part by modulating the expression of chemokines in bronchial tissues. (J Allergy Clin Immunol 1999;103:1054-61.) 相似文献
5.
Schirinzi A Centra M Prattichizzo C Gigante M De Fabritiis M Giancaspro V Petrarulo F Santacroce R Margaglione M Gesualdo L Ranieri E 《Molecular genetics and metabolism》2008,94(3):382-385
Fabry disease is an under-recognized X-linked lysosomal disorder, due to α-galactosidase A deficiency. Most of the mutations in the GLA gene are detectable using genomic sequencing analysis. However, deletions of one or more exons or deletion encompassing the entire gene are undetectable, especially in heterozygous females. The Multiplex Ligation-dependent Probe Amplification (MLPA) is an efficient tool for discovering these rearrangements. In this study two novel different deletions were detected using MLPA assay on two Fabry patients, both resulted mutation negative by sequencing analysis. These data suggest that this screening should be systematically included in genetic testing surveys of patients with Fabry disease. 相似文献
6.
Gabor Veres Timo Helin Andras Arato Martti Frkkil Annu Kantele Hanna Suomalainen Erkki Savilahti 《Clinical immunology (Orlando, Fla.)》2001,99(3):353
The mechanisms of adverse reactions to foods in the gastrointestinal tract are poorly understood. Previous studies of other atopic diseases and animal models suggest that adhesion molecules and mucosal lymphocytes may be implicated in the pathogenesis of food allergy (FA). The aim of our study was to investigate the expression of adhesion molecules and mucosal lymphocytes in duodena of patients with food allergies and of controls. Ten patients with FA to cereals (wheat, oats, and rye) or cow's milk and 9 control patients were included in the study. Quantitative analysis and immunohistochemical stainings for two pairs of adhesion molecules (intercellular adhesion molecule-1 (ICAM-1), lymphocyte function-associated antigen-1 (LFA-1), α4β7 integrin, and mucosal addressin cell adhesion molecule (MAdCAM-1) and lymphocyte markers on endoscopic duodenal biopsy specimens were performed. The villous structure and density of LFA-1-positive cells were normal in every biopsy specimen, but the patients had significantly more α4β7+ cells in the intraepithelial space (P = 0.01). The expression of ICAM-1 in the lamina propria of patients with FA was also substantially increased (P = 0.003); however, staining with MAdCAM showed no intergroup difference. Moreover, we found significantly increased CD4+ and HLA-DR+ cells in the lamina propria of patients, in comparison to the controls, P = 0.05 and P = 0.04, respectively. The densities of CD3, CD8, HLA-DP, T cell receptor αβ+ and γδ+ cells and IgA-, IgA1-, and IgA2-containing cells did not differ in the two groups studied. Our results suggest that the increased expression of ICAM-1 and α4β7 integrin may play an important role in the pathogenesis of food hypersensitivity and with the elevation of CD4- and HLA-DR-positive cells reflect a stage of inflammation in the structurally normal intestines. 相似文献
7.
Glen L. Alberts Jeffrey F. Pregenzer Wha Bin Im Jerry L. Slightom 《Neuroscience letters》2000,280(3):789
5-HT1 receptor subtypes (1B, 1D and 1F) have been implicated in migraine pathophysiology and their ligands have been examined for pharmacological actions in various experimental animal models. Considerable divergences exist, however, in their primary sequences between experimental animals and human, and additional models closer to human, such as non-human primates seem to be useful for migraine research. Earlier, we cloned the 5-HT1D, and here 5-HT1B and 5-HT1F receptors from the chimpanzee, gorilla and Rhesus monkey, via polymerase chain reactions with their genomic DNAs and primers designed from the corresponding human receptors. Direct sequencing of PCR products showed that the 5-HT1B receptors from the chimpanzee, gorilla and monkey differ from the human receptor by 0, 1 and 7 residues, respectively while 5-HT1F receptors differ by 0, 3 and 10 residues, respectively. These divergent residues are mostly conservatively substituted and also largely confined to the N-terminal region and the 3rd intracellular loop, away from transmembrane segments and intracellular loops near membrane which are critical for ligand binding and G protein coupling. The chimpanzee 5-HT1D, 5-HT1B and monkey 5-HT1F receptors, as heterologously expressed in human embryonic kidney 293 cells, showed robust agonist-induced guanosine 5′gamma 35S triphosphate (GTPγ35S) binding through activation of G proteins containing Gγi subunits. Moreover, pronounced inhibition of basal GTPγ35S binding by methiothepin (an antagonist), representing constitutively active receptors, was observed with only 5-HT1D. Overall, ligand binding and GTPγ35S binding profiles for these primate receptors are comparable to those for the human receptors and validate non-human primates as useful models for human migraine research. 相似文献
8.
The cell surface receptors of theYersinia pseudotuberculosisinvasin protein are theα3–6β1integrins. Invasin and the extracellular matrix protein fibronectin bind to the same or closely located sites onα5β1integrin, although invasin bind with a much greater affinity. Invasin-integrin interaction promotes bacterial penetration into eukaryotic cells. Binding of fibronectin to its integrin receptor seems to be dependent on terminal oligosaccharides processing. In this paper, we have examined the effect of 1-deoxymannojirimycin (dMNJ), an inhibitor of Golgiα-mannosidases involved in processing of N-glycan precursors, and of Brefeldin A (BFA), a natural product of fungi which has profound effects on the structure and function of the Golgi apparatus, on invasin–cell interaction. We found that unlike fibronectin, the interaction of invasin with cells was resistance to dMNJ. However, preincubating cells with BFA caused a dose dependent inhibition of invasin-mediated cell entry, while cell invasion bySalmonella typhimuriumwas not affected. 相似文献
9.
α- and β-adrenergic receptors belong to the superfamily of G-protein-coupled, seven transmembrane domain receptors and regulate a variety of cellular processes. Previous studies have demonstrated that changes in the amino acid sequence can result in substantial changes in the function of the receptors and it has been suggested that there may be an association between different disease states and the altered structure of α- and β-adrenergic receptors. Accordingly, we have developed a simple PCR method for the identification of polymorphisms in the coding sequences of the human β2-adrenergic receptor and the α1B-adrenergic receptor. This method may be useful for screening individual patients or at-risk populations for endocrine-metabolic disorders, as well as for asthma, cardiovascular disorders, and neuropsychiatric diseases. 相似文献
10.
Nuntia Teresa Sinopoli Antonella Pesce Anna Maria Baldassarre Glenwood E. Trivers Luigi Frati Cristina Rinaldi-Garaci 《Journal of immunological methods》1988,110(2)
Using a polyclonal specific rabbit anti-thymosin α1 a highly sensitive enzyme-linked immunosorbent assay (ELISA) has been developed to measure thymosin α1. Production of thymosin α1 was detected in both thymic organ cultures and in mouse serum. The method is rapid (5 h), reproducible and easy to perform. 相似文献
11.
Horst Claassen Joachim Hassenpflug Michael Schünke Walter Sierralta Hubert Thole Bodo Kurz 《Annals of anatomy》2001,183(3)
Clinical observations suggest that estrogens are involved in the pathogenesis of postmenopausal osteoarthritis, but only little is known about the influence of these hormones on articular cartilage cells. The effect of estradiol is mediated by estrogen receptors α and β. The goal of the present study was to search for estrogen receptor α in articular tissue from cows, pigs and humans by immunohistochemistry to form a basis for in vitro studies. In addition, we also tried to detect estrogen receptor α in cultivated articular chondrocytes from cows and bulls under certain culture conditions. Estrogen receptor α is detected by the use of antibody 13H2 in articular chondrocytes from cows, bulls, pigs and humans. Chondrocytes are physiologically exposed to reduced oxygen tension. In isolated articular chondrocytes from cows and bulls incubated either with 21% O2 or with 5% O2 positive cells were also found. These positive results therefore encourage testing the influence of estradiol on cultivated articular cartilage cells in these species under different culture conditions. 相似文献
12.
Ping Yang Julie M. Cunningham Kevin C. Halling Timothy G. Lesnick Lawrence J. Burgart Elaine M. Wiegert Eric R. Christensen Noralane M. Lindor Jerry A. Katzmann Stephen N. Thibodeau 《Molecular genetics and metabolism》2000,71(4):639
Microsatellite instability (MSI) is a genomic alteration observed in 15–30% of colorectal cancer (CRC). Two MSI phenotypes have been defined for CRC: MSI-H is characterized by MSI at ≥30% of the examined loci and MSI-L by MSI at 1–30% of the loci. An absence of MSI at any examined loci has been defined as a microsatellite stable (MSS) phenotype. Current data suggest the majority of MSI tumors are the result of defective DNA mismatch repair (MMR). In this study, we have determined the α1-antitrypsin deficiency carrier (α1ATD-ht) status of 161 CRC patients whose MSI phenotype and protein expression states had previously been determined. Cases were selected to enrich a larger number of MSI-H cases. Among 51 CRC patients with MSI-H tumors, the α1ATD-ht rate was 21.6%; among 110 patients with MSI-L/MSS tumors, the rate was 9.1% (MSI-H vs MSI-L/MSS, P = 0.02); and among the 191 population-based controls the α1ATD-ht rate was 9.4% (MSI-H vs controls, P = 0.02). The estimated relative risk of having MSI-H CRC among α1ATD-ht was 3.1 after adjusting for age, gender, and smoking history. The risk of having MSI-H CRC among current and past smokers was 6.6 and 2.7, respectively. Patients who were α1ATD-ht and smoked had a 20-fold increased risk of developing an MSI-H CRC compared to nonsmokers who were homozygous normal at the α1ATD locus. Our findings suggest an etiologic link between α1ATD alleles and development of CRC with defective MMR, and a synergistic effect between smoking and α1ATD allele in the development of MSI-H CRC. 相似文献
13.
The effect of melatonin on the γ-aminobutyric acidA (GABAA) receptor-mediated response was studied in cultured chick spinal cord neurons using the whole-cell voltage-clamp recording technique. Melatonin rapidly and reversibly potentiated the GABA-induced current in a dose-dependent fashion, with an EC50 of 766 μM and a maximal potentiation of 148%. Potentiation of the GABA response by melatonin was mediated by increasing the potency of GABA rather than the efficacy. Prolonged exposure to a saturating concentration of the disulfide-reducing agent dithiothreitol did not attentuate the effect of melatonin on the GABA response, indicating that melatonin does not act through the redox site. Furthermore, our results demonstrate that melatonin and 5α-pregnan-3α-ol-20-one (a positive steroid modulator of the GABAA receptor) act through different sites. 相似文献
14.
Kirtibala Gupta MSc Againdra Bewtra MD 《The Journal of allergy and clinical immunology》1999,103(6):1100
Background: IL-1 has 2 receptors, type I (IL-1RI) and type II (IL-1RII), which have 2 forms each, membrane (m) and soluble (s). When IL-1 binds to mIL-1RI, the active receptor, an inflammatory response is initiated, which does not occur when IL-1 binds to mIL-1RII, the decoy receptor. Both sIL-1RI and sIL-1RII function as IL-1–mopping mechanisms. We hypothesized that the ratio of active (mIL-1RI) to inactive (mIL-1RII, sIL-1RI, and sIL-1RII) receptors is important in determining the amount of inflammation produced in allergic reactions. Objective: Our aim was to compare the concentrations of mIL-1RI and mIL-1RII on cultured PBLs and sIL-1RI, sIL-1RII, and IL-1β in sera and supernatants of cultured PBMCs from atopic and nonatopic subjects. Methods: The membrane receptors, soluble receptors, and IL-1β concentrations were measured by ELISA with specific mAbs. Results: Although there was no difference in the level of serum IL-1β between the 2 groups, PBMCs from atopic persons spontaneously secreted higher levels of IL-1β than those from nonatopic donors (P < .05). PBLs from atopic subjects compared with those from nonatopic individuals expressed higher mIL-1RI (P < .0001) and mIL-1RII (P < .05). Levels of both the soluble receptors from both serum (P < .0001) and PBMCs (P < .05) of nonatopic donors were higher than those found in atopic donors. Conclusion: This augmentation of mIL-1RI concomitant with a reduction in soluble receptors may be an important contributory factor to the inflammation that occurs with allergen exposure. (J Allergy Clin Immunol 1999;103:1100-7.) 相似文献
15.
R. F. Menzeleev A. I. Bozhkov E. N. Zvonkova Yu. M. Krasnopol'skyii V. I. Shvets 《Bulletin of experimental biology and medicine》1995,119(4):414-417
In experiments on rats subjected to partial hepatectomy and experimentally induced hepatitis it is shown that GM3 ganglioside of equine erythrocytes can enhance liver cell proliferation. The effect was also observed in experiments on a
primary hepatocyte culturein vitro; moreover, enhancement of cell proliferation did not depend on the type of sialic acid residues.
Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N
o
4, pp 427–430, April, 1995 相似文献
16.
Viel TA Lima Caetano A Nasello AG Lancelotti CL Nunes VA Araujo MS Buck HS 《Neurobiology of aging》2008,29(12):1805-1814
Although numerous inflammation pathways have been implicated in Alzheimer's disease, the involvement of the kallikrein–kinin system is still under investigation. We anatomically localized and quantified the density of kinin B1 and B2 receptors binding sites in the rat brain after the infusion of amyloid-β (Aβ) peptide in the right lateral brain ventricle for 5 weeks. The conditioned avoidance test showed a significant reduction of memory consolidation in rats infused with Aβ (68.6 ± 20.9%, P < 0.05) when compared to control group (90.8 ± 4.1%; infused with vehicle). Autoradiographic studies performed in brain samples of both groups using [125I]HPP-[des-Arg10]-Hoe-140 (150 pM, 90 min, 25 °C) showed a significant increase in density of B1 receptor binding sites in the ventral hippocampal commissure (1.23 ± 0.07 fmol/mg), fimbria (1.31 ± 0.05 fmol/mg), CA1 and CA3 hippocampal areas (1.05 ± 0.03 and 1.24 ± 0.02 fmol/mg, respectively), habenular nuclei (1.30 ± 0.04 fmol/mg), optical tract (1.30 ± 0.05 fmol/mg) and internal capsule (1.26 ± 0.05 fmol/mg) in Aβ group. For B2 receptors ([125I]HPP-Hoe-140, 200 pM, 90 min, 25 °C), a significant increase in density of binding sites was observed in optical tract (2.04 ± 0.08 fmol/mg), basal nucleus of Meynert (1.84 ± 0.18 fmol/mg), lateral septal nucleus – dorsal and intermediary portions (1.66 ± 0.29 fmol/mg), internal capsule (1.74 ± 0.19 fmol/mg) and habenular nuclei (1.68 ± 0.11 fmol/mg). In control group, none of these nuclei showed [125I]HPP-Hoe-140 labeling. This significant increase in densities of kinin B1 and B2 receptors in animals submitted to Aβ infusion was observed mainly in brain regions related to cognitive behavior, suggesting the involvement of the kallikrein–kinin system in Alzheimer's disease in vivo. 相似文献
17.
Edwige Dunn Jean-Marc Fritschy Donald B. Carter Kalpana M. Merchant 《Neuroscience letters》1996,210(3):213
A detailed mapping of the γ-aminobutyric acid (GABA)A receptor subunits (α1, α2, α3 and β2+3) in the infralimbic/ventral prelimbic region (IL/vPL) of the rat frontal cortex was carried out using subunit-specific antibodies. The α1 and β2+3 subunit antibodies immunostained all layers of the IL/vPL region. Layers II and III displayed immunostaining of cell bodies whereas I, V and VI showed predominantly neuropil staining. The size of the α1-positive cell bodies corresponded to that of small interneurons (range, 20–55 μm2; mean ± SEM, 37 ± 5.5 μm2) as well as pyramidal cells or large interneurons (range, 87–135 μm2; mean ± SEM, 103.4 ± 9.7 μm2). However, β2+3 antibody immunostained only small cell bodies. Immunoreactivity for α2 was restricted to layers I and II, whereas α3 and α5 subunit expression was seen only in layer VI. The antibody to the α2 subunit immunostained small cell bodies (range, 29–63 μm2; mean ± SEM, 32 ± 4.5 μm2) in layer II, resembling interneurons. Conversely, both α3 and α5 antibodies immunostained large cell bodies (range, 94–151 gmm2; mean ± SEM, 115.7 ± 13.4 μm2), consistent with pyramidal cell labelling in layer VI. 相似文献
18.
Kelk P Claesson R Chen C Sjöstedt A Johansson A 《International journal of medical microbiology : IJMM》2008,298(5-6):529-541
Aggregatibacter (Actinobacillus) actinomycetemcomitans forms a leukotoxin that selectively lyses primate neutrophils, monocytes and triggers apoptosis in promyeloic cells and degranulation of human neutrophils. Recently, we showed that the leukotoxin causes activation of caspase-1 and abundant secretion of bio-active IL-1β from human macrophages. In this study, we show that high levels of IL-β correlated with a high proportion of A. actinomycetemcomitans in clinical samples from a patient with aggressive periodontitis. To determine the relative contribution of leukotoxin to the overall bacteria-induced IL-1β secretion, macrophages were isolated from peripheral blood and exposed to different concentrations of live A. actinomycetemcomitans strains with either no, low or high production of leukotoxin. Cell lysis and levels of IL-1β, IL-6, TNF-α and caspase-1 were measured by ELISA and flow cytometry. Leukotoxin was the predominant cause of IL-1β secretion from macrophages, even in the A. actinomycetemcomitans strain with low leukotoxin production. Macrophages exposed to non-leukotoxic bacteria accumulated cytosolic pro-IL-1β, which was secreted by a secondary exposure to leukotoxic bacteria. In conclusion, the present study shows for the first time that A. actinomycetemcomitans-induced IL-1β secretion from human macrophages in vitro is mainly caused by leukotoxin. 相似文献
19.
Karl Lis Helmut Acker Dietrich Werner Lübbers Martin Halle 《Pflügers Archiv : European journal of physiology》1979,381(3):289-291
APCO2 electrode working on the principle of electrical conductivity is described. The calibration curve can be linearized according to the formula
. This linearity has been tested in thePCO2 range of 0.93–9.33 kPa (7–70 Torr). For the experiments electrodes are used which have conductivity values of about 50 nS and drifts of maximally 5%/h at aPCO2 of 5.33 kPa (40 Torr). The response time (T
90) is about 20 s. The temperature sensitivity is 2.4 nS/1 K between 298K–310K. The standard error of the measurements is =0.33 nS. With these electrodes tissuePCO2 can be measured on the surface of various organs. 相似文献
20.
Cristiana Valle Anna Rita Troiani Alfredo Festucci Livia Pica-Mattoccia Piero Liberti Adrian Wolstenholme Katherine Francklow Michael J. Doenhoff Donato Cioli 《Molecular and biochemical parasitology》2003,130(2):111
Kohn et al. [J. Biol. Chem. 276 (2001) 36873] demonstrated that cells expressing the structurally unusual schistosome β subunit SmCavβ1 in their voltage-operated calcium channels, exhibit an increased current amplitude in the presence of praziquantel (PZQ). This suggests that the beta subunit is involved in PZQ activity and is consistent with the known pharmacological effects of the drug. If this is so, the low susceptibility to PZQ noted in some Schistosoma mansoni strains could be due to some mutation(s) in the gene coding for this protein. We have sequenced the cDNAs coding for the SmCavβ1 and SmCavβ2 subunits of different sensitive and resistant strains and we have not been able to detect any meaningful differences. As an alternative hypothesis, the different sensitivity of schistosomes to PZQ action could be due to the expression of different β subunits in the parasite. This interpretation could also explain the low PZQ susceptibility of immature worms (28 days). We analyzed Northern blots of various strains and various developmental stages, but we were unable to demonstrate major quantitative differences in the expression of the β subunits. 相似文献