Role for T-cell receptor Vb genes in collagen induced-arthritis.
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Animals↗
Biomedical subjects
C David
Publications and source records attributed to C David.
Substrate specificity of the luminal Na(+)-dependent sulphate transport system in the proximal renal tubule as compared to the contraluminal sulphate exchange system.
The efflux of [35S]sulphate from the lumen of the proximal renal tubule into tubular cells of rats was measured by the stop-flow tubular-lumen microperfusion technique. The transport parameters obtained and the apparent Ki values of competing substrates were compared with those of the contraluminal influx of [35S]-sulphate from the interstitium into tubular cells. For the luminal sulphate efflux a Km(l, SO4(2-)) of 0.8 mmol/l and a Jmax(l, SO4(2-)) of 0.2 pmol s-1 cm-1 were found. The corresponding contraluminal values were Km(cl,SO4(2-)) 1.4 mmol/l and Jmax(cl,SO4(2-)) 1.2 pmol s-1 cm-1. Omission of Na+ from the perfusates reduced the luminal efflux of sulphate by 83%, while the contraluminal influx of sulphate was not changed. Increase in HCO3- concentration inhibited both luminal efflux and contraluminal influx of sulphate, while a change of pH from 6.0 to 8.0 was without effect. Comparing the apparent Ki(SO4(2-)) values for luminal and contraluminal sulphate transport, a relationship close to 1:1 was seen for some inorganic substrates with tetrahedral molecular structure (thiosulphate, sulphate, molybdate and selenate). The same holds for phosphate, while for oxalate the contraluminal Ki(SO4(2-)) value was lower than the luminal one (1.2 and 4.5 mmol/l). Some of the dicarboxylates and disulphonates tested show the same affinity to the luminal Na(+)-dependent sulphate transporter and the contraluminal sulphate exchange system, whereas most of the benzene carboxylate and benzenesulphonate derivatives tested exhibit higher luminal than contraluminal Ki values. The inhibitory potency increased with rising numbers of substituents on the benzene ring. This effect was more pronounced for the contraluminal sulphate transporter. In general, only disulphonates and analogues as well as similarly structured compounds (5-sulphosalicylate, 2-hydroxy-5-nitrobenzenesulphonate, eosine-5-isothiocyanate) have a good inhibitory potency toward the luminal sulphate transporter [apparent Ki 0.9-3.1 mmol/l]. All the tested sulphamoyl and phenoxy diuretics, and fluorescein and phenolphthalein dyes showed no or a smaller inhibitory potency to the luminal sulphate transport system than to the contraluminal. The most effective inhibitors of both sulphate transport systems are 8-anilino-1-naphthalenesulphonate, orange G, and H2-DIDS. The data indicate that the Na(+)-dependent luminal and the Na(+)-independent contraluminal sulphate transport systems accommodate a similar spectrum of anionic substrates, whereby the inhibitory potency against the luminal Na(+)-dependent sulphate transport system is identical or smaller than against the contraluminal transporter.
Animals↗
RNA replication of plant viruses containing an RNA genome.
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Base Sequence↗
Evidence for a correlation between auxin production and host plant species among strains of Pseudomonas syringae subsp. savastanoi.
Auxin production by 131 strains of Pseudomonas syringae subsp. savastanoi was investigated with the aim of looking for correlations among this characteristic and the origin of the strains, the types of symptoms, and the host plant. Most of the P.syringae subsp. savastanoi strains, except those isolated from ash, produced auxin and harbored iaa genes. Among ash strains, which were pathogenic only on ash, only 2 out of 33 were found to produce auxin and to harbor iaa genes.
Indoleacetic Acids↗
An economic assessment of twin births in British dairy herds.
The effect of twinning on the subsequent health, production and reproductive performance of dairy cattle was studied by analysing the data derived from 19,755 calvings which occurred during three years on 37 farms. The data formed part of the database of a veterinary practice operating the DAISY dairy cow recording scheme for its dairy farmer clients. The average twinning rate was 2.5 per cent. For first calf heifers the rate was 0.9 per cent, and the rate increased with increasing parity to over 5 per cent for cows calving for their sixth and subsequent lactations. Although they produced more milk than their contemporaries, twin-bearing cows suffered an increased incidence of retained placenta and vulval discharges and their calving to conception interval was extended by 33 days. Furthermore, 35 per cent of these cows were culled compared with 21 per cent of their contemporaries. The benefit of having more calves for sale was reduced owing to 15 per cent of them being born dead. It is calculated that producing twins resulted in an average loss of income of 74 pounds/cow, a deficit of 15 per cent compared with cows having single calves.
Animals↗
The 3' promoter region involved in RNA synthesis directed by the turnip yellow mosaic virus genome in vitro.
We have previously shown that the last 100 nucleotides from the 3' end of turnip yellow mosaic virus (TYMV) RNA compete in vitro with genomic RNA for the TYMV-specific RNA-dependent RNA polymerase (RdRp). To further characterize the promoter on genomic RNA that produces complementary RNA strands, shorter fragments corresponding to the 3' region of the viral RNA were generated and used in in vitro assays. Fragments as short as 38 nucleotides corresponding to the 3' end of TYMV RNA compete with the viral RNA for the RdRp suggesting that the 3' promoter on plus strand RNA is probably less than or equal to 38 nucleotides long. These transcripts are themselves used as templates in vitro.
Base Sequence↗
[Acute purulent polyarthritis induced by Streptobacillus moniliformis].
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Acute Disease↗
Antipeptide antibodies differentiate between long and short isoforms of the D2 dopamine receptor.
We have developed specific antibodies directed against two synthetic peptides corresponding to defined sequences in the D2 dopamine receptor. One peptide is from a region that is present only in the 'long' isoform of the receptor, whereas the other is from a region that is common to both. These antibodies are able to recognize the native receptor as judged by immunocytochemical staining of cells transfected with dopamine receptor DNA. One antibody was shown to be specific for the 'long' form of the receptor and reacts only with cells transfected with the 'long' DNA subtype and not with those transfected with the 'short' DNA subtype. This recognition is specific and can be inhibited by the corresponding free peptide and not by a non-relevant peptide.
Amino Acid Sequence↗
[Treatment of legionellosis with ofloxacin in kidney transplanted patients. Lack of interaction with cyclosporin A].
Seven cases of legionellosis were observed in a series of 81 renal transplant recipients. In the 6 patients with functional graft, pneumonia occurred 17 days on average after the beginning of transplant rejection treatment. The diagnosis was made by bronchoalveolar lavage: the direct immunofluorescence antigen technique was positive in 5 cases and culture in 6 cases. Legionella pneumophila sero-groups 5 and 1 were identified in one and 5 patients respectively. Six of the 7 patients were treated with ofloxacin. This fluoroquinolone was effective in all cases. It was administered as single therapy in 3 patients and did not interfere with ciclosporin A metabolism. Ofloxacin given in mean doses of 400 mg per day adjusted to renal function proved to be a simple, effective and well tolerated treatment of legionellosis in transplant recipients receiving ciclosporin A.
Adult↗
Contraluminal transport of organic cations in the proximal tubule of the rat kidney. I. Kinetics of N1-methylnicotinamide and tetraethylammonium, influence of K+, HCO3-, pH; inhibition by aliphatic primary, secondary and tertiary amines and mono- and bisquaternary compounds.
In order to study the characteristics of contraluminal organic cation transport from the blood site into proximal tubular cells the stopped-flow capillary perfusion method was applied. The disappearance of N1-[3H]methylnicotinamide (NMeN+) and [3H]tetraethylammonium (TEA+) at different concentrations and contact times was measured and the following parameters evaluated: Km,NMeN = 0.54 mmol/l, Jmax,NMeN = 0.4 pmol s-1 cm-1; Km,TEA = 0.16 mmol/l, Jmax,TEA = 0.8 pmol s-1 cm-1. TEA+ inhibited NMeN+ transport and NMeN+ the uptake of TEA+. Thereby, the Ki values for inhibition correspond closely to the Km values for uptake. Similar inhibitory potencies of ten organic cation against TEA+ and NMeN+ transport provide further evidence for a common transport system. Omission of HCO3-, or Na+ and addition of K+ (with or without Ba2+) reduce NMeN+ transport, while omission of K+ (with or without valinomycin) or addition of thiocyanate has no effect. Since the manoeuvres that depolarize contraluminal electrical potential difference reduce NMeN+ transport, cell-negative electrical potential difference is suggested as a driving force for contraluminal organic cation transport from the interstitium into the cell. Furthermore, the inhibitory potency (app. Ki values) of homologous series of primary, secondary, tertiary and hydroxy amines as well as of mono- and bisquaternary ammonium compounds against NMeN+ transport was tested. The inhibitory potency increased in the sequence methyl less than ethyl less than propyl less than butyl and primary less than secondary less than tertiary amines less than quaternary ammonium compounds.(ABSTRACT TRUNCATED AT 250 WORDS)
Amines↗
Fluconazole therapy for chronic disseminated candidiasis in patients with leukemia and prior amphotericin B therapy.
OBJECTIVE: To study the efficacy of fluconazole against chronic disseminated candidiasis (hepatosplenic candidiasis) in patients with leukemia in whom amphotericin B treatment had failed. DESIGN: Retrospective analysis of patients with chronic disseminated candidiasis treated with fluconazole on a compassionate investigational new drug protocol. SETTING: Multi-institutional. PATIENTS AND METHODS: Twenty consecutive patients received 100 to 400 mg of fluconazole per day for a median of 30 weeks. All had either failed to respond to treatment with more than 2 g of amphotericin B or had serious amphotericin B-related toxicities. RESULTS: Fourteen of 16 evaluable patients (88%) responded. Responses were observed in seven of nine patients in whom adequate doses of amphotericin B had failed and in all seven patients who had amphotericin B-related toxicities. In 12 patients, cytotoxic chemotherapy was continued without flare of the infection. Fluconazole was well tolerated with rare side effects. Aspergillus superinfection developed in three patients and contributed to the death of two of them. CONCLUSION: Fluconazole is a safe and effective agent with significant activity against chronic disseminated candidiasis.
Adult↗
Integration site-dependent expression of a transgene reveals specialized features of cells associated with neuromuscular junctions.
After skeletal muscle is denervated, fibroblasts near neuromuscular junctions proliferate more than fibroblasts distant from synaptic sites, and they accumulate adhesive molecules such as tenascin (Gatchalian, C. L., M. Schachner, and J. R. Sanes. 1989. J. Cell Biol. 108:1873-1890). This response could reflect signals that arise perisynaptically after denervation, preexisting differences between perisynaptic and extrasynaptic fibroblasts, or both. Here, we describe a line of transgenic mice in which patterns of transgene expression provide direct evidence for differences between perisynaptic and extrasynaptic fibroblasts in normal muscle. Transgenic mice were generated using regulatory elements from a major histocompatibility complex (MHC) class I gene linked to the Escherichia coli beta-galactosidase (lacZ) gene. Expression of lacZ was detected histochemically. In each of eight lines, lacZ was detected in different subsets of cells, none of which included lymphocytes. In contrast, endogenous MHC is expressed in most tissues and at high levels in lymphocytes. Thus, the MHC gene sequences appeared inactive in the transgene, and lacZ expression was apparently controlled by genomic regulatory elements that were specific for the insertion site. In one line, cells close to the neuromuscular junction were lacZ positive in embryonic and young postnatal mice. Electron microscopy identified these cells as fibroblasts and Schwann cells associated with motor nerve terminals, as well as endoneurial fibroblasts, perineurial cells, and Schwann cells in the distal branches of motor nerves. No intramuscular cells greater than 200 microns from synaptic sites were lacZ positive. These results indicate that there are molecular differences between perisynaptic and extrasynaptic fibroblasts even in normal muscle and that diverse perisynaptic cell types share a specific pattern of gene expression.
Animals↗
Antigenic mimicry and autoimmune diseases.
The finding of cross-reactive autoantibodies or sequence homology does not necessarily mean that this molecular mimicry is biologically meaningful or associated with disease pathogenesis. For example, relatives of persons with putative autoimmune insulin-dependent diabetes [123], and elderly humans [124] have a high incidence of autoantibodies which are generally not associated with autoimmune disease. In addition, natural antibodies to cell constituents [125] may be present in normal sera. These antibodies need to be directed against biologically important domains of host cell proteins in order to mediate autoimmune disease [27]. In spite of extensive homology between two sequences, a cross-reactive immune response may not be generated. The dissimilar amino acids should not be radical substitutions or affect the binding properties of the molecule. For instance, antibodies to synthetic peptides with only one substitution in a 19 amino acid sequence may not bind the whole protein [126]. Despite an identical six amino acid sequence shared by HLA-B27 and an EBV protein, no cross-reactive antibodies to EBV peptides were found in HLA-B27 positive patients with AS or RS. Unless the homology and subsequent crossreactive immune response can recognize a host protein intimately involved in disease pathogenesis, autoimmune disease is unlikely to occur.
Amino Acid Sequence↗
[A new case of autochthonous visceral leishmaniasis in Bolivia].
A sixth autochthonous case of visceral leishmaniasis is reported in Bolivia. It is also the fourth case detected in the Yungas Valley (Department of La Paz) confirming the long-term existence of the disease in this area where cases of canine leishmaniasis and natural infestation of the phlebotomine sandfly, Lutzomyia longipalpis, were previously reported.
Antimony Sodium Gluconate↗
Antipeptide antibodies localize N-(4-azido-3-[125I] iodophenethyl)spiperone binding to the carboxyl-terminal portion of the D2 dopamine receptor.
Antibodies against synthetic peptides of the D2 dopamine receptor were used, in combination with photoaffinity labeling, to localize the region of ligand binding in the receptor. Specific antibodies to peptide sequences 221-234 and 259-272 and to the carboxyl-terminal peptide 402-415, all corresponding to cytoplasmic regions in the D2 dopamine receptor, were elicited. After photoaffinity labeling with N-(4-azido-3-[125I]iodophenethyl)spiperone ([125I]NAPS), all three antibodies specifically immunoprecipitated the 90-kDa D2 dopamine receptor. Differential reactivity of the antipeptide antibodies with various proteolytic fragments indicates that [125I]NAPS binds covalently to a 13-kDa fragment of the D2 dopamine receptor. This fragment is immunoprecipitated with anti-peptide 402-415 and not with the other two antipeptide antibodies, indicating that the photoaffinity ligand binds to a fragment that begins beyond amino acid 272 and extends through the carboxyl-terminal end of the receptor.
Affinity Labels↗
[Isolation of Legionella pneumophila by the Isolator blood culture system in a female renal graft recipient].
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Female↗
Isolation and partial characterization of ascites sialoglycoprotein-2 of the cell surface sialomucin complex of 13762 rat mammary adenocarcinoma cells.
Sialomucins are the dominant components of the cell surfaces of some carcinoma ascites cells and have been postulated to inhibit recognition of tumours by the immune system. The sialomucin ASGP-1 (ascites sialoglycoprotein-1) of the 13762 rat mammary adenocarcinoma is associated with the cell surface as a complex with a concanavalin-A-binding glycoprotein called ASGP-2. This sialomucin complex has been purified from ascites cell microvilli by extraction with Triton X-100 and CsCl density-gradient centrifugation. ASGP-1 (which has been purified previously) and ASGP-2 were dissociated in 6 M-guanidine hydrochloride and separated by gel filtration. The molecular mass of the undenatured detergent complex of ASGP-2, estimated by gel filtration and velocity sedimentation in Triton X-100, was 148 kDa. Since the apparent molecular mass by SDS/polyacrylamide-gel electrophoresis was about 120 kDa, ASGP-2 must be a monomer as extracted from the membrane. Studies of its chemical composition indicate that it contains about 45% carbohydrate by weight, including both mannose and galactosamine. Alkaline borohydride treatment of ASGP-2 converted approx. half of the N-acetylgalactosamine to N-acetylgalactosaminitol, demonstrating the presence of O-linked oligosaccharides. Analyses of mannose-labelled Pronase glycopeptides from ASGP-2 by lectin-affinity chromatography on concanavalin A and leucocyte-agglutinating phytohaemagglutinin suggested that 40% of the label was present in high-mannose/hybrid oligosaccharides, 20% in triantennary oligosaccharides substituted on the C-2 and C-4 mannose positions and 40% in tri- or tetra-antennary oligosaccharides substituted on C-2 and C-6. The presence of polylactosamine sequences on these oligosaccharides was suggested by lectin blots and by precipitation from detergent extracts with tomato lectin. From chemical analyses and lectin-affinity studies, we estimate that ASGP-2 contains four high-mannose and 13 complex N-glycosylated oligosaccharides, plus small amounts of polylactosamine and O-linked oligosaccharides. The presence of four different classes of oligosaccharides on this glycoprotein suggests that it will be an interesting model system for biosynthetic comparisons of the different glycosylation pathways.
Adenocarcinoma↗
Comparison of four indirect methods for fluid superoxide dismutase activities.
Relatively small sample dilutions could render fluid extracellular (EC) superoxide dismutase (SOD) activity assays more subject to interfering compounds than tissue SOD assays. Highly variable relative SOD activities were obtained when comparing four indirect assays for several fluid samples (human plasma, human synovial fluid, and plasma from healthy or inflamed rats). Analysis of rat plasma fractionated with Sephadex G-150 showed that each assay (three xanthine oxidase based assays plus a modified pyrogallol assay) detected apparent SOD activity almost entirely at the same molecular weight as rat lung EC SOD. However, unfractionated fluid samples caused interferences with the xanthine oxidase based SOD assays, though not with the pyrogallol method. Example of interference were stimulation of xanthine oxidase activity, color formation without xanthine oxidase, color formation despite excess Cu-Zn SOD addition, and absorbance changes with cyanide inhibition of EC SOD that were above or below blank values. In summary, relative fluid SOD values depended on the assay used, and a modified pyrogallol assay was not subject to several interferences found for three xanthine oxidase based assays of fluid SOD activity.
Animals↗