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Biomedical subjects

C Ruiz

Publications and source records attributed to C Ruiz.

At least 19 recordsLinked to original sources
PubMed2000

Regulatory mechanisms for modulation of signaling through the cell integrity Slt2-mediated pathway in Saccharomyces cerevisiae.

Signal transduction mediated by the mitogen-activated protein kinase (MAPK) Slt2 pathway is essential to maintain the cell wall integrity in Saccharomyces cerevisiae. Stimulation of MAPK pathways results in activation by phosphorylation of conserved threonine and tyrosine residues of MAPKs. We have used an antibody that specifically recognizes dually phosphorylated Slt2 to gain insight into the activation and modulation of signaling through the cell integrity pathway. We show that caffeine and vanadate activate this pathway in the absence of osmotic stabilization. The lack of the putative cell surface sensor Mid2 prevents vanadate- but not caffeine-induced Slt2 phosphorylation. Disruption of the Rho1-GTPase-activating protein genes SAC7 and BEM2 leads to constitutive Slt2 activation, indicating their involvement as negative regulators of the pathway. MAPK kinases also seem to participate in signaling regulation, Mkk1 playing a greater role than Mkk2 in signal transmission to Slt2. Additionally, one of the phosphatases involved in Slt2 dephosphorylation is likely to be the dual specificity phosphatase Msg5, since overexpression of MSG5 in a sac7Delta mutant eliminates the high Slt2 phosphorylation, and disruption of MSG5 in wild type cells results in increased phospho-Slt2 levels. These data present the first evidence for a negative regulation of the cell integrity pathway.

DNA-Binding Proteins↗
PubMed1999

GEM, a cluster of repetitive sequences in the Drosophila subobscura genome.

GEM is a new family of repetitive sequences detected in the D. subobscura genome. Two of the four described GEM elements encompass a heterogeneous central module, with no detectable ORF, flanked by two long inverted repeats. These elements are composed of a set of repetitive modules, which are inverted repeat (IR), direct repeat (DR), palindromic sequence (PS), long sequence (LS) and short sequence (SS). These five modules can be found either clustered or dispersed as single modules in the D. subobscura genome, in euchromatic and heterochromatic regions. In addition to the 3' region of Adh retrosequences, single IR and LS blocks were found associated with the promoter region of different genes, in particular, LS-like blocks have also been found associated with functional genes in D. melanogaster and D. virilis. Conversely, the DR block is highly similar to satellite DNAs from some other species of the obscura group. In addition, GEM elements share some structural features with IS elements described in different Drosophila species. It is likely that both GEM and IS sequences would be vestiges of an ancestral transposable element.

Alcohol Dehydrogenase↗
PubMed1999

A large-scale sonication assay for cell wall mutant analysis in yeast.

The complete yeast genome contains a large number of genes of unknown biological function. Simple, rapid and reliable specific screens are valuable tools in exploring gene function via systematic phenotypic analysis of large mutant collections. This report provides a new approach for monitoring changes in cell wall strength, based on the deleterious effects caused by ultrasound on the yeast cell surface. Sonication can thus be used for the screening of mutants affected in the architecture or stability of the cell wall, since such mutants are expected to have an altered sensitivity to this treatment compared to that of a wild-type. The experimental procedure, consisting in the quantification of damaged cells after a mild sonication treatment, by means of flow cytometry, can be applied on a large scale. The usefulness of the sonication assay as a primary screen for cell wall-related mutants is evaluated on the collection of calcofluor white-hypersensitive and -resistant mutants obtained by Lussier et al. (1997). A further phenotypic characterization of the sonication-hypersensitive mutants within the calcofluor white collection is also presented.

Benzenesulfonates↗
PubMed1999

Percutaneous mitral valve dilatation with the Multi-Track System.

We developed the Multi-Track System for percutaneous mitral valvotomy and described the preliminary results in 1995. Here we report the first 100 consecutive cases after the original publication. Two separate balloon catheters are positioned on a single guidewire. The first catheter, with only a distal guidewire lumen, is introduced into the vein and then advanced into the mitral orifice. Subsequently, a rapid exchange balloon catheter running on the same guidewire is inserted and lined up with the first catheter so the two are positioned side by side. Both balloons are then inflated simultaneously. Age of the patients was 31 +/- 12.8 years and weight 50 +/- 14 kg. Valve area increased 0.75 +/- 0.22 cm(2) to 2.00 +/- 0.32 cm(2)and mean left atrial pressure dropped from 27 +/- 8 to 11 +/- 5 mm Hg. One patient had significant mitral insufficiency after dilatation, which did not require surgery. The Multi-Track System is a valid alternative to the existing procedures for the treatment of mitral stenosis and uses simpler and less costly catheters. Cathet. Cardiovasc. Intervent. 48:178-183, 1999.

Adolescent↗
PubMed1999

Thyroid status modulates glycoxidative and lipoxidative modification of tissue proteins.

Steady state protein modification by carbonyl compounds is related to the rate of carbonyl adduct formation and the half-life of the protein. Thyroid hormones are physiologic modulators of both tissue oxidative stress and protein degradation. The levels of the glycation product N(epsilon)-fructoselysine (FL) and those of the oxidation products, N(epsilon)-(carboxymethyl)lysine (CML) and malondialdehyde-lysine (MDA-lys), identified by GC/MS in liver proteins, decreased significantly in hyperthyroid rats, as well as (less acutely) in hypothyroid animals. Immunoblotting of liver proteins for advanced glycation end-products (AGE) is in agreement with the results obtained by GC/MS. Cytosolic proteolytic activity against carboxymethylated foreign proteins measured in vitro was significantly increased in hypo- and hyperthyroidism. Oxidative damage to DNA, estimated as 8-oxo-7,8-dihydro-2'-deoxyguanosine (8oxodG), did not show significant differences between groups. The results suggests that the steady state levels of these markers depend on the levels of thyroid hormones, presumably through their combined effects on the rates of protein degradation and oxidative stress, whereas DNA is more protected from oxidative damage.

8-Hydroxy-2'-Deoxyguanosine↗
PubMed1999

The acquisition of competence to respond to ecdysone in Drosophila is transcript specific.

The steroid hormone ecdysone induces a precise sequence of gene activity in Drosophila melanogaster salivary glands in late third larval instar larvae. The acquisition of competence for this response does not result from a single event or pathway but requires factors that accumulate throughout the instar. Individual transcripts become competent to respond at different times and their expression is differentially affected in ecd1, dor22 and BR-C mutants. The induction of early-late transcripts, originally assumed to necessarily follow early transcripts, is partially independent of early transcript activation. Attempts to inhibit the synthesis of regulatory proteins reveal transcript-specific superinduction effects. Furthermore these inhibitors lead to the induction of betaFTZ-F1 and E93 transcripts at levels normally found in prepupal glands. These studies reveal the complexity of the processes underlying the establishment of a hormonal response.

Animals↗
PubMed1999

Lipid peroxidation and antioxidant enzyme activities in patients with type 1 diabetes mellitus.

To evaluate oxidative stress in type I diabetes mellitus, two antioxidant enzymes in erythrocytes, copper-zinc superoxide dismutase (SOD EC 1.15.1.1.) and seleno-dependent glutathione peroxidase (GSH-Px; EC 1.11.19), and two indexes of peroxidation in plasma, thiobarbituric acid reactive substances (TBARS) and organic hydroperoxides (OHP), were measured in 118 patients with insulin-dependent diabetes mellitus (IDDM), classified in accordance with the presence or absence of vascular complications and the degree of metabolic control established by the HbA1c level. Ninety healthy subjects made up the control group. According to our results, plasmatic TBARS and OHP concentrations are significantly higher in diabetics than in controls, and these differences are accentuated in diabetic people with vascular disorders. The GSH-Px activity was significantly reduced in diabetic patients with poor and medium metabolic control in relation to the control group, regardless of the existence or absence of vascular disorders. No differences in SOD activity between diabetic and control groups were found. A significant positive correlation between TBARS and HPO (r=0.683, p<0.001) was found in both the control and diabetic groups. Among the lipid parameters studied, there were only significantly positive correlations between TBARS and total cholesterol; TBARS and triglycerides; OHP and total cholesterol and OHP and triglycerides. Positive correlations between TBARS and HbA1c and between OHP and and HbA1c, and negative correlations between GSH-Px and HbA1c and between SOD and HbA1c were also found. The multiple regression analysis shows that TBARS and HPO correlate negatively with GSH-Px. There was no significant correlation with SOD.

Adult↗
PubMed1999

Human decidual stromal cells express alpha-smooth muscle actin and show ultrastructural similarities with myofibroblasts.

Previous reports in human and mouse material demonstrated that decidual stromal cells expressed antigens associated with haematopoietic cells, exerted immune functions, and originated from bone marrow. These findings suggested that these cells belonged to the haematopoietic lineage. We purified and expanded in culture precursors of human decidual stromal cells, and found in electron microscopic images that the ultrastructure of these cells was similar to that of myofibroblasts, which are of mesenchymal origin. The relationship between these two types of cell was confirmed by the detection (by flow cytometry) in the decidual precursors of alpha-smooth muscle actin, a contractile microfilament expressed solely by smooth muscle cells, myofibroblasts and related cells. This filament was also detected in decidual stromal cells decidualized in vitro by the effect of progesterone. We also found vimentin in decidual precursors and decidualized cells. This intermediate filament has been previously reported to be expressed by all decidual stromal cells and also by myofibroblasts. Desmin, another intermediate filament expressed by myofibroblasts, was not detected in the decidual precursors; however, this filament was observed in decidualized cells. The expression of alpha-smooth muscle actin by decidual stromal cells was also found by immunostaining in cryostat sections of early decidua. Our results suggest that decidual stromal cells are related to myofibroblasts.

Actins↗
PubMed1999

A role for maternal serum screening in detecting chromosomal abnormalities in fetuses with isolated choroid plexus cysts: a prospective multicentre study.

A prospective multicentre study was performed to identify patients with fetal choroid plexus cysts and examine the association between choroid plexus cysts and chromosome abnormalities in the context of variables such as maternal age, serum triple-screen results, race, other prenatally-identified fetal anomalies and cyst characteristics. A total of 18 437 scans were performed in 5 centres and 257 fetuses were identified with choroid plexus cysts. Outcome was available on 250 patients, and of these, chromosomal abnormalities were detected in a total of 13 (5.2 per cent) fetuses. 26 patients in the group had additional ultrasound abnormalities, and 8 of these had fetal chromosome abnormalities. Among the 224 patients with isolated choroid plexus cysts, 5 (2.2 per cent) were found to have chromosomal abnormalities. All cases with identified chromosomal abnormalities were associated with an additional risk factor, such as other ultrasound findings, advanced maternal age or abnormal maternal serum triple-screen results.

Adolescent↗
PubMed1999

Effect of Halococcus morrhuae and Halobacterium saccharovorum on the activation of human peripheral blood lymphocytes.

The immunomodulator properties of two species of halophilic Archaebacteria, Halobacterium saccharovorum and Halococcus rnorrhuae, were analysed by the study of lymphocyte activation. Two methods were used to detect activation in lymphocytes, namely incorporation of the radioactive nucleotide [3H]-thymidine, and CD25 expression. H. morrhuae had a stimulatory effect on human lymphocytes, but this action was observed only with the [3H]-thymidine uptake method, whereas H. saccharovorum produced no immunomodulator effect.

Adult↗
PubMed1998

ACTH and beta-endorphin in transcendental meditation.

We have evaluated the effect of Transcendental Meditation (TM) on the hypothalamo-hypophyseal-adrenal axis diurnal rhythms through the determination of hormone levels. Blood samples were taken at 0900 hours. and at 2000 hours. These samples were taken from 18 healthy volunteers who regularly practice TM and from nine healthy non-meditators. Cortisol, beta-endorphin, and adrenocorticotropic hormone (ACTH) were measured at both hours. TM practitioners showed no diurnal rhythm for ACTH and for beta-endorphin (ACTH, pg/mL, mean +/- SE; 13.8+/-1.2 - 12.1+/-1.5/beta-endorphin, pg/mL; 14.4+/-1.5 - 17.2+/-1.9, at 0900 hours and 2000 hours, respectively), in contrast to control subjects, who showed normal diurnal rhythm for these hormones and for cortisol (ACTH, pg/mL; 19.4+/-1.9 - 11.9+/-2.2/beta-endorphin, pg/mL; 25.4+/-1.7 - 17.7+/-1.1/Cortisol, ng/mL; 201.4+/-13.2 - 71.3+/-6.5, at 0900-2000 hours, respectively, p < 0.01 in the three cases). Practitioners of TM with similar anxiety levels to those of the control group showed a different pattern in the daytime secretion of pituitary hormones. TM thus appears to have a significant effect on the neuroendocrine axis. Because cortisol levels had a normal pattern in the TM group, these results may be due to a change in feedback sensitivity caused by this mental technique.

Adrenocorticotropic Hormone↗
PubMed1998

Pruritic urticarial papules and plaques of pregnancy: clinical and immunopathologic observations in 57 patients.

BACKGROUND: Pruritic urticarial papules and plaques of pregnancy (PUPPP) has been described either as a homogeneous or a polymorphic clinical process. Its cause is unknown. OBJECTIVE: We attempted to characterize the clinical and immunopathologic findings in PUPPP on the basis of long-term clinical and immunopathologic observations. METHODS: The clinical and immunopathologic features of 57 patients with PUPPP were evaluated. RESULTS: The clinical features in 57 patients with PUPPP were categorized into three types: mainly urticarial papules and plaques (type I), nonurticarial erythema, papules, or vesicles (type II), and combinations of the two forms (type III). Direct immunofluorescence studies in 48 of the 57 patients showed nonspecific immunoreactants in dermal blood vessels and/or moderate granular deposits at the dermoepidermal junction in 15 patients. CONCLUSION: Type I PUPPP differed from types II and III in clinical appearance and distribution (absence of face, palm, and sole lesions), but trimester onset, parity, and direct immunofluorescence findings were not significantly different among the three groups.

Adolescent↗
PubMed1998

Gene array and expression of mouse retina guanylate cyclase activating proteins 1 and 2.

PURPOSE: To identify gene arrangement, chromosomal localization, and expression pattern of mouse guanylate cyclase activating proteins GCAP1 and GCAP2, retina-specific Ca2+-binding proteins, and photoreceptor guanylate cyclase activators. METHODS: The GCAP1 and GCAP2 genes were cloned from genomic libraries and sequenced. The chromosomal localization of the GCAP array was determined using fluorescent in situ hybridization. The expression of GCAP1 and GCAP2 in mouse retinal tissue was determined by immunocytochemistry. RESULTS: In this study, the mouse GCAP1 and GCAP2 gene array, its chromosomal localization, RNA transcripts, and immunolocalization of the gene products were fully characterized. The GCAP tail-to-tail array is located at the D band of chromosome 17. Each gene is transcribed into a single transcript of 0.8 kb (GCAP1) and 2 kb (GCAP2). Immunocytochemistry showed that both GCAP genes are expressed in retinal photoreceptor cells, but GCAP2 was nearly undetectable in cones. GCAP2 was also found in amacrine and ganglion cells of the inner retina. Light-adapted and dark-adapted retinas showed no significant difference in the distribution of the most intense GCAP2 staining within the outer segment and outer plexiform layers. CONCLUSIONS: Identical GCAP gene structures and the existence of the tail-to-tail gene array in mouse and human suggest an ancient gene duplication-inversion event preceding mammalian diversification. Identification of both GCAPs in synaptic regions, and of GCAP2 in the inner retina suggest roles of these Ca-binding proteins in addition to regulation of phototransduction.

Adaptation, Ocular↗
PubMed1998

Mitochondrial membrane peroxidizability index is inversely related to maximum life span in mammals.

The oxidative stress theory of aging predicts a low degree of fatty acid unsaturation in tissues of longevous animals, because membrane lipids increase their sensitivity to oxidative damage as a function of their unsaturation. Accordingly, the fatty acids analyses of liver mitochondria from eight mammals, ranging in maximum life span from 3.5 to 46 years, show that the total number of double bonds and the peroxidizability index are negatively correlated with maximum life span (r = -0. 88, P < 0.003; r = -0.87, P < 0.004, respectively). This is not due to a low content of unsaturated fatty acids in longevous animals, but mainly to a redistribution between kinds of the polyunsaturated n-3 fatty acids series, shifting from the highly unsaturated docosahexaenoic acid (r = -0.89, P < 0.003) to the less unsaturated linolenic acid (r = 0.97, P < 0.0001). This redistribution pattern strongly suggests the presence of a constitutively low delta6-desaturase activity in longevous animals (r = -0.96, P < 0.0001). Thus, it may be proposed that, during evolution, a low degree of fatty acid unsaturation in liver mitochondria may have been selected in longevous mammals in order to protect the tissues against oxidative damage, while maintaining an appropriate environment for membrane function.

Aging↗
PubMed1997

The human GCAP1 and GCAP2 genes are arranged in a tail-to-tail array on the short arm of chromosome 6 (p21.1).

GCAP1 and GCAP2 are related Ca(2+)-binding proteins that activate photoreceptor guanylate cyclase(s). We showed previously that the human GCAP1 gene, consisting of four exons, is located at 6p21.1 (locus designation GUCA). To identify the chromosomal location of the GCAP2 gene, we first cloned its cDNA and determined its intron-exon distribution by PCR analysis. The results show that the introns of the GCAP2 gene are positioned exactly as in the GCAP1 gene and are nearly double in size. Sequence similarity between the two genes, however, is limited to portions of exons 1 and 2. The GCAP1 and GCAP2 genes are transcribed into single mRNA species (1.7 and 2.2 kb, respectively) and are detectable only in the retina by Northern blotting. The GCAP2 gene was found by somatic human-hamster hybrid panel analysis and FISH to reside at GUCA in a region indistinguishable from that of GCAP1. PCR analysis with exon 4-specific primers showed that the genes are in a tail-to-tail array less than 5 kb apart and altogether span less than 20 kb of genomic DNA. The identical gene structures and loci of GCAP1 and GCAP2, and the identical function of the gene products, are consistent with gene duplication event.

Amino Acid Sequence↗
PubMed1997

Cardiopulmonary and haemodynamic changes during total hip arthroplasty.

We report a prospective study of 30 patients who underwent total hip arthroplasty for osteoarthrosis in order to investigate the haemodynamic and respiratory changes which occur during operation. Cement was used in 17 cases and the implants were not cemented in 13. Pulmonary and cardiac function, blood levels of methylmethacrylate monomer, intramedullary pressure and transoesophageal echocardiography were recorded. Two well differentiated echogenic patterns appeared consistently during the operation. The intramedullary pressure became raised as the cement was inserted. The following changes occurred within seconds and continued for some minutes: elevation of mean arterial pressure and mean pulmonary artery pressure; decrease of arterial oxygen tension and of mixed venous PO2, and greater tissue consumption of oxygen. Although we recorded raised concentration of methylmethacrylate monomer in venous blood after the cement was inserted, there is no evidence that the monomer is responsible for the haemodynamic changes which take place.

Aged↗