Active oxygen metabolism in the senescence of pea leaves: ascorbate and glutathione contents in different cell compartments.
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Ascorbic Acid↗
Biomedical subjects
A Jimenez
Publications and source records attributed to A Jimenez.
Chemopreventive effect of S-allylcysteine and its relationship to the detoxification enzyme glutathione S-transferase.
Sulfur-containing substances derived from garlic and onion have been shown to prevent experimental carcinogenesis. One of the hypotheses explaining the mechanisms of the chemopreventive activity of these substances is that they activate detoxification systems such as glutathione S-transferase (GST). In this study the effects of S-allylcysteine (SAC), a water-soluble organosulfur compound derived from garlic, on GST activities in the liver, small intestine and colon were investigated. Additionally, we examined SAC for chemopreventive effects on aberrant crypt foci, which are the most likely precursors of colon cancers. In the rat colonic aberrant crypt assay administration of SAC during the initiation period decreased the number of aberrant crypt foci by 33 and 54% in groups given 40 or 80% maximum tolerated dose (MTD) of SAC respectively. The number of aberrant crypt foci, however, was not changed when SAC was given during the promotion period. GST activity in the liver was increased significantly by 41% 12 h after a single oral administration of 3.5 mmol/kg SAC and this elevated GST level was maintained over a 72 h period. GST levels were increased significantly by the administration of SAC (1.8 mmol/kg/ day for 3 days) not only in the liver but also in the proximal and middle small bowel. Isozyme levels of GST after administration of SAC were also determined using Western blotting. Hepatic GST-alpha and GST-mu were significantly increased by 35 and 42% respectively after oral administration of SAC. GST-pi levels were lower than the detection limit (130 ng/mg/protein) in both the control and SAC-treated groups. These results strongly support the previous working hypothesis that SAC exhibits chemopreventive activity by exerting specific effects on carcinogen detoxification systems.
1,2-Dimethylhydrazine↗
Risk behavior and HIV seroincidence among out-of-treatment injection drug users: a four-year prospective study.
We monitored trends in HIV risk behaviors and seroconversion among out-of-treatment injection drug users (IDUs) receiving street-based outreach intervention. Beginning in 1988, 641 HIV-seronegative IDUs were recruited by targeted sampling methods to reflect broader IDU populations and were followed for 4 years (1988-1992). All were active injectors not in treatment when recruited. Cohort members were targets of HIV-prevention outreach. The intervention was guided by the Indigenous Leader Outreach Model: Exaddicts deliver HIV-prevention services targeting IDU social networks in community settings. Primary outcome measures were HIV seroconversion and HIV risk behaviors. Observed incidence of HIV infection decreased, from 8.4 to 2.4 per 100 person-years. Prevalence of drug risk behaviors also decreased, from 100 to 14%. Seroconversion was associated with injection risk behavior [risk ratio (RR) = 9.8]. Sex risk behavior also decreased, but less dramatically, from 71 to 45%. Out-of-treatment IDUs in Chicago have reduced their rates of new HIV infection by reducing their injection risk behavior. New infections were strongly associated with injection risk behavior but not with sex risk behavior.
Adolescent↗
Diagnostic value of three tumor markers determined in pleural effusions.
In order to discriminate between malignant and benign effusions, the values of tissue polypeptide specific antigen,carcinoembryonic antigen and squamous cell carcinoma associated antigen were measured in the pleural fluid of 30 patients with neoplasm, 10 with tuberculous pleurisy, 10 with transudates due to congestive heart failure or cirrhosis, 29 with parapneumonic effusions and 23 with benign diseases other than tuberculosis and pneumonia. Carcinoembryonic antigen and tissue poly-peptide specific antigen levels in effusions due to neoplasms were significantly higher than those in effusions due to other diseases. The areas under Receiver Operating Characteristic curves for carcinoembryonic antigen and tissue polypeptide specific antigen determinations were 0.69 and 0.67, respectively. No significant differences were found in the pleural fluid squamous cell carcinoma associated antigen levels between neoplasms and other diseases. The ability of tissue polypeptide specific antigen and carcinoembryonic antigen to discriminate between benign and malignant effusions may be considered comparable. Although both carcinoembryonic antigen and tissue polypeptide specific antigen showed a low accuracy (the number of undiagnosed pleural effusions is considerably high), both tissue polypeptide specific antigen and carcinoembryonic antigen determinations may contribute to a correct diagnostic classification. Moreover, the combination of these markers provides a specificity of 97.2%. However, the low number of positivities obtained for tissue polypeptide specific antigen and carcinoembryonic antigen together (13 cases in our series) reveals the need for further investigations.
Adult↗
Aberrant crypts as a biomarker for colon cancer: evaluation of potential chemopreventive agents in the rat.
We assessed the effects of 41 potential chemopreventive agents in the F344 rat using the inhibition of carcinogen-induced aberrant crypt foci (ACF) in the colon as the measure of efficacy. ACF were induced by the carcinogen azoxymethane in F344 rats by two sequential weekly injections at a dose of 15 mg/kg. Two weeks after the last azoxymethane injection, animals were evaluated for the number of aberrant crypts detected in methylene blue-stained whole mounts of rat colon. The 41 agents were derived from a priority listing that was based on reports of chemopreventive activity in the literature and/or efficacy data from in vitro models of carcinogenesis. The list of agents included representative examples of phytochemicals, vitamins, minerals, inhibitors of proliferation, inducers of Phase 1 and Phase 2 metabolism systems, nonsteroidal anti-inflammatory agents, and differentiation agents. Eighteen agents were positive in the assay, significantly reducing the incidence of ACF at least in one of two doses tested. As a chemical class, the nonsteroidal anti-inflammatory drugs, which included ibuprofen, ketoprofen, piroxicam, and indomethacin, were most active; other less potent agents were arginine, butylated hydroxyanisole, curcumin, diallyl sulfide, difluoromethylornithine, 18 beta-glycyrrhetinic acid, indole-3-carbinol, oltipraz, purpurin, rutin, and the sodium salts of butyrate, selenite, and thiosulfate. Twenty-three agents did not inhibit ACF; included among these were several agents that promoted the development of ACF at one or both doses tested: benzyl isothiocyanate,calcium glucarate, catechin, dihydroepiandosterone, fluocinolone acetonide,folic acid, levamisole, 2-mercaptoethanesulfonic acid, nordihydroguiaretic acid, potassium glucarate, propyl gallate, beta-sitosterol, sodium cromolyn, sodium molybdate, and sulfasalazine. The aberrant crypt assay demonstrates reasonable specificity and sensitivity in predicting which agents are likely to prevent colon cancer.
Animals↗
The ard1 gene from Streptomyces capreolus encodes a polypeptide of the ABC-transporters superfamily which confers resistance to the aminonucleoside antibiotic A201A.
A gene (ard1) encoding resistance to the aminonucleoside antibiotic A201A was cloned from Streptomyces capreolus NRRL 3817, the producing organism, and expressed in Streptomyces lividans. The gene ard1 induced antibiotic resistance that was highly specific for A201A. The nucleotide sequence of ard1 contains an open reading frame of 1677 bp. Transcription initiation was found to take place approximately 86 nucleotides preceding the ATG translation-initiation codon, indicating that ard1 is transcribed from its own promoter. The deduced protein sequence (Ard1, 558 amino acids) presents two ATP-binding domains with significant similarities to those of the ATP-binding cassette transporters (ABC-transporters) superfamily, including some that confer drug resistance in a variety of antibiotic-producing Streptomyces, other Gram-positive bacteria and eukaryotic cells. As is probably the case for most of these proteins, the mechanism of A201A resistance conferred by Ard1 is an active efflux energized by ATP hydrolysis.
ATP-Binding Cassette Transporters↗
Factors determining the radioactivity levels of waters in the province of Cáceres (Spain).
In an extensive study of different types of water in the province of Cáceres (Spain) in order to determine their total alpha- and total beta-radioactivity contents, several factors were found to have a decisive influence on their radioactivity levels. Thus, parameters such as total hardness and pH can be determinative according to the lithological type of the aquifer or according to the subterranean or surface origin of the hydrological resource. Waters from classic lithologies, or originating from a well, possess above-average radioactivity indices, surpassing in numerous cases the indicative levels set by current Spanish legislation. In contrast, surface waters from rivers, in practically all cases, possess below-average radioactivity indices.
Fresh Water↗
Evaluation of zone electrophoresis of serum proteins performed on the Helena Laboratories rapid electrophoresis analyser.
Zone electrophoresis of serum proteins is still widely performed as a routine procedure in clinical laboratories. It is used in the diagnosis and management of many disorders, e.g. monoclonal gammopathies, cirrhosis, nephrotic syndrome, acute-phase reaction, immunoglobulin deficiency and others. The aim of this work is to evaluate the analytical performance of zone electrophoresis of serum proteins carried out in the Helena Laboratories Rapid Electrophoresis analyser (REP) comparing the results with those obtained in the Olympus Hite System 200 (HS-200). The REP system employs agarose gel as support medium, the HS-200 system employs cellulose acetate and it is the routine method in our laboratory. To date, we have not found any paper that deals with the assessment of a system for performing zone electrophoresis of serum proteins in terms of comparison with another.
Adolescent↗
Intracellular expression of the monoclonal anti-ras antibody Y13-259 blocks the transforming activity of ras oncogenes.
Microinjection of the anti-ras antibody Mab Y13-259 modifies ras function and can induce temporary reversion of the transformed phenotype in mutant ras-transformed cells. Intracellular production of neutralizing antibodies represents an approach to investigate the regulation of gene function. The genes coding for the heavy and light chains of Mab Y13-259 were isolated from a cDNA library. NIH3T3 cells transfected with heavy and light chain expression vectors produced functional anti-ras antibody. The production of functional antibody did not require glycosylation. To ensure that the antibody entered the cytoplasm and not the secretory pathway, the hydrophobic leader sequences of both chains were removed and replaced with synthetic initiator sequences. The modified heavy chain gene was cloned under the control of the murine sarcoma virus long terminal repeat, and the light chain gene under the control of the mouse mammary tumor virus long terminal repeat, which allows the induction of light chain expression in the presence of dexamethasone. When both heavy and light chain genes were expressed in cells with activated ras (morphologically transformed) in the presence of dexamethasone, we observed phenotypic reversion to characteristics of nontransformed cells. These experiments show that intracellular expression of antibodies can also be used as an alternative to analyze biological functions of a given protein.
3T3 Cells↗
Complete DNA sequence of yeast chromosome XI.
The complete DNA sequence of the yeast Saccharomyces cerevisiae chromosome XI has been determined. In addition to a compact arrangement of potential protein coding sequences, the 666,448-base-pair sequence has revealed general chromosome patterns; in particular, alternating regional variations in average base composition correlate with variations in local gene density along the chromosome. Significant discrepancies with the previously published genetic map demonstrate the need for using independent physical mapping criteria.
Base Sequence↗
Influence of stabilization occlusal splint on craniocervical relationships. Part II: Electromyographic analysis.
The aim of this study was to determine the effect of stabilization occlusal splints on electromyographic (EMG) activity of sternocleidomastoid and trapezius muscles in subjects with spasm in the mentioned muscles. A full-arch maxillary stabilization occlusal splint was made for each of the 15 subjects. In the sternocleidomastoid muscle, tonic and saliva swallowing EMG activity decreased significantly with the splint, whereas maximal clenching activity did not change. In the trapezius muscle, no significant changes were observed with the occlusal splint. The different pattern in both muscles during tonic and swallowing EMG activity with the splint is attributed to differences in the synaptic inputs to the respective motoneuron pools, suggesting that a differential modulation of the motor neuron pools may exist of both muscles, of peripheral and/or central origin.
Adult↗
Spontaneous bovine respiratory syncytial virus infection in goats: pathological findings.
This paper presents the results of a study of eight cases of natural bovine respiratory syncytial virus (BRSV) infection in a herd of 50 Murciana kids from a intensive goat-farm in Spain. Clinical and pathological analysis confirmed the existence of natural BRSV infection in eight kids. In two of the eight animals there was also evidence of concurrent infection with P. haemolytica A.
Animals↗
The pur8 gene from the pur cluster of Streptomyces alboniger encodes a highly hydrophobic polypeptide which confers resistance to puromycin.
A novel puromycin-resistance determinant (pur8) was isolated from one end of the pur cluster that encodes the puromycin biosynthetic pathway from Streptomyces alboniger and expressed in Streptomyces lividans. The gene pur8 induced antibiotic resistance that was highly specific for puromycin. The nucleotide sequence of pur8 contains an open reading frame of 1512 bp whose deduced amino acid sequence encodes a polypeptide (Pur8) with 14 possible transmembrane-spanning segments. It shows significant similarities to other known or putative transmembrane proteins, including a number which confer drug resistance in a variety of antibiotic-producing Streptomyces, Gram-positive and Gram-negative bacteria, and some solute transporters of prokaryotic and eukaryotic origin. As is probably the case for most of these proteins, Pur8 may be involved in active puromycin efflux energized by a proton-dependent electrochemical gradient. In addition, it could be implicated in secreting N-acetylpuromycin, the last intermediate of the biosynthesis pathway, to the environment.
Amino Acid Sequence↗
The complete sequence of a 15,820 bp segment of Saccharomyces cerevisiae chromosome XI contains the UBI2 and MPL1 genes and three new open reading frames.
As part of the EEC yeast genome program, a fragment of 15,820 bp from the right arm of Saccharomyces cerevisiae chromosome XI has been sequenced. This fragment corresponds roughly to the centromere-distal half of cosmid pUKG046 and to a small fragment of cosmid pUKG096, which are located approximately 150 kb from the centromere. It contains four open reading frames (ORFs) which encode potential proteins of more than 100 amino acid residues, as well as the UBI2 gene which carries an intron and does not show up as an ORF in the sequence analysis programs. One of the putative proteins, YKR412, is very rich in serine and has significant homology at the carboxyl end to Nopp140 phosphoprotein. YKR413 has several predicted transmembrane domains. YKR15, which has been recently cloned as the MPL1 gene, encodes a polypeptide that shows homologies to myosin heavy chain and to the cytoskeleton protein Uso1.
Amino Acid Sequence↗
Effect of leukotrienes of renal water excretion.
To investigate the renal actions of leukotrienes (LT), we infused arachidonic acid into the renal artery of anesthetized dogs during systemic cyclooxygenase inhibition (with ibuprofen) alone or in combination with lipoxygenase inhibition or LTD4/LTE4 receptor antagonism. Renal arachidonic acid infusion following ibuprofen alone decreased urine osmolality (945 +/- 143 to 698 +/- 144 mosm/kg; p < 0.01) and increased urine flow rate (0.34 +/- 0.11 to 0.56 +/- 0.16; p < 0.05) without altering renal blood flow, glomerular filtration rate or sodium excretion. In separate groups, prior inhibition of lipoxygenase (propylgallate) or blockade of LTD4/LTE4 receptors (LY171883) prevented the changes in urine osmolality and urine flow rate. Intrarenal oleic acid infusion following ibuprofen had no effect on renal function. Analysis of the renal papillae at the end of the experiment indicated that interstitial osmolality and sodium, potassium and urea contents were the same in all groups, ruling out a decrease in papillary interstitial osmolality as the cause of the decrease in urine osmolality in the arachidonic acid-infused group. Our experiments suggest that renal LT can decrease urine osmolality and increase urine flow rate and may play a role in renal water excretion.
Acetophenones↗
Identification of the gene encoding an N-acetylpuromycin N-acetylhydrolase in the puromycin biosynthetic gene cluster from Streptomyces alboniger.
The biologically inactive compound N-acetylpuromycin is the last intermediate of the puromycin antibiotic biosynthetic pathway in Streptomyces alboniger. Culture filtrates from either this organism or Streptomyces lividans transformants harboring the puromycin biosynthetic gene cluster cloned in low-copy-number cosmids contained an enzymic activity which hydrolyzes N-acetylpuromycin to produce the active antibiotic. A gene encoding the deacetylase enzyme was located at one end of this cluster, subcloned in a 2.5-kb DNA fragment, and expressed from a high-copy-number plasmid in S. lividans.
Amidohydrolases↗
Cephalometric changes in a patient with ectodermal dysplasia after placement of dentures.
The purpose of this article is to analyze the changes observed in a three-year-old boy affected of ectodermal dysplasia after the placement of complete dentures. Esthetic, functional as well as cephalometric changes are discussed.
Anodontia↗
Dentures for a 3-yr-old child with ectodermal dysplasia: case report.
A case of a 3-year-old boy with X-linked hypohidrotic ectodermal dysplasia is presented. Complete maxillary and mandibular dentures were made at 3 years and 2 months of age. The process for making the dentures is described. Obtaining enough patient cooperation and proper application of behavioral management techniques are critical factors for the procedure described in the article.
Anodontia↗