SEARCH · Search PubMed
Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
The infectious ribonucleic acid (RNA) of potato spindle tuber virus (PSTV) can be separated by hydroxyapatite chromatography from double-stranded RNA detectable in low amounts in both infected and uninfected plant tissue extracts. The chromatographic behavior of ribonuclease-sensitive PSTV RNA resembles that of transfer RNA.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
1. The pyridine haemochrome-cleaving activity of extracts from mammalian liver and other tissues is shown conclusively to be entirely non-enzymic in nature and attributable to coupled oxidation with ascorbate. 2. Reduced glutathione probably contributes to the activity indirectly by continuously regenerating the ascorbate to the reduced form. 3. The cleavage shows no specificity for the alpha-methine bridge of pyridine haemochrome. 4. Results are presented suggesting some probable reasons for the erroneous characterization of the activity as an alpha-methine-specific haem-cleaving enzyme (;haem alpha-methenyl oxygenase') by Nakajima and co-workers (e.g. Nakajima, Takemura, Nakajima & Yamaoka, 1963; Nakajima & Gray, 1967).
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Proteins modified by oxidants are rapidly degraded by intracellular proteases. Oxidatively modified superoxide dismutase (Ox-SOD) was degraded 2-8 times faster at both acidic and alkaline pH than the native protein in bovine cardiac tissue extracts. At acidic pH, Ox-SOD hydrolysis was stimulated by ATP and by non-hydrolyzable ATP analogs by up to 50%, but degradation was not stimulated by ATP at alkaline pH. The aspartic protease inhibitor pepstatin completely inhibited the acid Ox-SOD hydrolyzing activity and its stimulation by ATP. This activity eluted from gel filtration with a molecular size of 34-48 kDa and contained the single chain and two mature forms of cathepsin D. Purified cathepsin D degraded Ox-SOD and ATP enhanced the affinity of cathepsin D for oxidatively modified proteins. Thus cardiac tissue proteins modified by oxidants may be substrates for the lysosomal protease cathepsin D.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Explore the source record for details and available documents.
Haemolymph, heads, salivary glands, crops, midguts, hindguts, and Malpighian tubules from Rhodnius prolixus and Triatoma infestans were extracted in phosphate or Tris buffer saline with calcium, and tested for agglutination and lytic activities by microtitration against both vertebrate erythrocytes and cultured epimastigote forms of Trypanosoma rangeli. Haemagglutination activity against rabbit erythrocytes was found in the crop, midgut and hindgut extracts of T. infestans but only in the haemolymph of R. prolixus. Higher titers of parasite agglutinins were found in R. prolixus haemolymph than T. infestans, whilst the converse occurred for the tissue extracts. In addition, the extracts of T. infestans salivary glands, but not those of R. prolixus, showed a trypanolytic activity that was heat-inactivated and was not abolished by pre-incubation with any of the sugars or glycoproteins tested. T. infestans, which is refractory to infection by T. rangeli, thus appears to contain a much wider distribution of agglutinating and trypanolytic factors in its tissues than the more susceptible species, R. prolixus.
The goal of this study was to delineate the effects of dopamine antagonists on the regulation of preproenkephalin mRNA and opioid peptides in the rat brain. We have developed a method whereby both mRNA and peptides can be efficiently measured in the same tissue extract, thus reducing the effects of intraspecies variation, differences in dissection and the number of animals required for statistical significance. A sub-chronic dose of haloperidol (3 mg/kg given i.p. in 100 microliters DMSO daily for 5 days) produced a 1.8-fold increase (P less than 0.001) in striatal preproenkephalin mRNA levels when compared to animals injected with vehicle dimethyl sulfoxide (DMSO) employing the same schedule. Total opioid peptides as measured by a radioimmunoassay directed to the N-terminus of enkephalins and endorphins were elevated 1.6 fold (P less than 0.001) in the rat striatum. However in other brain regions examined no increases were observed either in preproenkephalin mRNA or the tissue levels of opioid peptides. Analysis of the opioid-like immunoreactive peptides by reverse-phase HPLC analysis showed no dramatic changes in the ratios of the various opioid peptides between haloperidol and vehicle injected animals. Naive animals showed no statistical differences in opioid peptide levels compared to the haloperidol treated animals. There was a statistically significant decrease (30%) in the opioid peptide content of the animals injected with vehicle daily for 5 days when compared with the animals merely sacrificed, or those given acute injections (either with haloperidol or vehicle) the day of sacrifice.(ABSTRACT TRUNCATED AT 250 WORDS)
A sandwich-type ELISA has been developed for the assessment of complexes between urokinase-type plasminogen activator (uPA) and its receptor (uPAR) in extracts of squamous cell lung carcinomas. The assay is based on a combination of rabbit polyclonal anti-uPA antibodies and a biotinylated mouse anti-uPAR monoclonal antibody (MAb). The detection limit of the assay is approximately 0.5 fmol/ml. A linear dose-response is obtained with up to 40 fmol/ml of uPA:uPAR complexes, while uPA and uPAR separately do not cause any response in the ELISA. A buffer which has been used previously for optimal extraction of uPAR yields the highest amounts of uPA:uPAR complexes. Absorption of tumor extracts with anti-uPA or anti-uPAR MAbs results in a complete disappearance of the ELISA signal, demonstrating the specificity of the ELISA. The recovery of chemically cross-linked uPA:uPAR complexes added to tumor extracts varies between 80% and 105%. The intra- and inter-assay variation coefficients are 5.3% and 9.8%, respectively. Furthermore, a peptide antagonist for uPAR was employed to evaluate de novo uPA:uPAR complex formation during tumor tissue extraction and the immunoassay procedure. Our results strongly indicate that de novo complex formation is a major factor to consider and that complexes analyzed in the presence of this antagonist represent original uPA:uPAR complexes present prior to tumor tissue processing. The present ELISA appears suitable for studying the potential prognostic impact of uPA:uPAR complexes in lung tumor tissue as well as other types of cancer.
Explore the source record for details and available documents.
Explore the source record for details and available documents.