Search PubMed⌕ Search

Biomedical subjects

C Ramos

Publications and source records attributed to C Ramos.

At least 127 records · Page 7Linked to original sources
PubMed1996

Increased expression of intercellular adhesion molecule 1, CD11/CD18 cell surface adhesion glycoproteins and alpha 4 beta 1 integrin in a rat model of chronic interstitial lung fibrosis.

The expression of the intercellular adhesion molecule 1 (ICAM-1), and the integrins CD49, CD11b/c, and CD11a (LFA-1 alpha chain) was analyzed in an experimental model of pulmonary fibrosis. Adult rats were exposed to 75% oxygen during 10 weeks, and to 2.0 mg/kg of paraquat twice weekly. Rats were sacrificed at 2 days, and at 2 and 10 weeks after the first injection of paraquat. Lungs were fixed in 4% paraformaldehyde and used for histology and immunohistochemistry. At 2 days the lungs showed a diffuse inflammation composed of a mixed polymorphonuclear and mononuclear cell infiltrate. Afterwards, the inflammatory process was predominantly mononuclear, and an increasing fibroblast proliferation was observed. Early inflammatory events (48 h) correlated with a moderate increased expression of ICAM-1, LFA, and CD11b/c in epithelial cells as well as a pronounced expression of ICAM-1 and CD11b/c in macrophages. At 2 and 10 weeks, there was a progressive increased expression of CD11b/c and ICAM-1 by macrophages, as well as of LFA in epithelial cells, and of ICAM-1 and CD49 by epithelial and interstitial cells. Lymphocytes showed a slight increased expression of LFA at 2 weeks, and of CD49 at 2 and 10 weeks. These results suggest that macrophages expressing ICAM-1, CD11b/c, and CD49 are involved in the earlier and late phases of the disease whereas fibroblast and epithelial cells expressing ICAM-1 and CD49 might play a role in the cell interactions involved in the fibrotic phase.

Animals↗
PubMed1996

Bronchiolitis in chronic pigeon breeder's disease. Morphologic evidence of a spectrum of small airway lesions in hypersensitivity pneumonitis induced by avian antigens.

We analyzed 36 open lung biopsy specimens from patients with chronic pigeon breeder's disease (PBD) to assess bronchiolar involvement and its relationship to the parenchymal pathologic abnormalities. Likewise, 21 biopsy specimens obtained from patients with usual interstitial pneumonia (UIP) were also examined. The bronchiolar abnormalities were scored by the method of Wright et al using a panel of photographs. In addition, the severity of lung fibrosis was evaluated in all samples and expressed as percentage in multiples of ten. A variable degree of epithelial cell metaplasia, bronchiolar inflammation and fibrosis, smooth muscle hypertrophy, extrinsic small airways narrowing, and intraluminal macrophages was observed in both diseases. Occasionally, hyperplasia of lymphoid follicles was also present. Bronchiolar changes were proportional in type and severity to the parenchymal damage. Spearman's nonparametric correlation between fibrosis in parenchyma and fibrosis in membranous bronchiole for the complete group (including patients with UIP and with PBD) showed a moderate but significant association (R = 0.51; p < 0.01). A significant association was also demonstrated when the score for bronchiolar fibrosis and inflammation was evaluated in relation to lung fibrosis divided in high degree (> 50%) and low degree (< 50%), respectively. In the case of patients with PBD, the correlation between bronchiolar and parenchymatous fibrosis was of 0.33 (p < 0.05). In general, bronchiolar fibrosis was less severe and inflammation more severe in PBD lungs compared with patients with UIP. Fibrosis in membranous bronchioles correlated with increased mortality in the complete group of patients, but the impact on mortality disappeared after correcting for overall fibrosis in the biopsy sample. Our findings demonstrate that a spectrum of bronchiolar lesions is usually observed in chronic PBD lungs, although the predominant pattern is similar to that found in the surrounding parenchyma, suggesting that the damage occurs in parallel.

Adult↗
PubMed1996

Prevalence of antibodies to the repeat epitope of the circumsporozoite protein of Plasmodium vivax in San Luis Potosi, Mexico.

The prevalence of antibodies against the repeat epitope of the circumsporozoite protein (cs) of the standard (PV210) and variant (PVK247) strain of Plasmodium vivax was determined by ELISA in 1170 sera from individual residents of seven localities of the Region Huasteca of San Luis Potosi, Mexico. The capture antigens were the synthetic peptides DDAAD and (ANGAGNQPG) that correspond to the repeats of the PV210 and PVK247 cs proteins, respectively. Of the analyzed serum samples, 34.1% (400/1170) were positive with one or both of these antigens. Of the sera, 18.2% (214/1170) reacted with the DDAAD peptide and 6.6% (78/1170) were positive with the variant synthetic peptide. Additionally, 9.2% (108/1170) of the samples reacted with both peptides. A sample of 10% of positive sera for the variant cs repeat (18/78) was tested with the cs repeat peptide of P. malariae/P. brasilianum (NAAG); almost all of them (16/18, 89%) being positive. These results confirm that the transmission of the variant strain of P. vivax is a common phenomenon in endemic regions in Latin America, as well as in other tropical regions of the world. These findings may have implications for the development of aP. vivax vaccine since that based on the standard cs repeat only would not be universally protective.

Amino Acid Sequence↗
PubMed1995

A sandwich ELISA based on anti-apo(a) and anti-apo B monoclonal antibodies for lipoprotein(a) measurement.

Lipoprotein(a) (Lp(a)) is one of the most important independent risk factors for the prediction of premature atherosclerosis. Lp(a) is a low-density lipoprotein (LDL)-like particle which contains a glycoprotein (apoprotein(a)) disulfide linked to apo B-100. We describe a sandwich ELISA based on an anti-apo(a) monoclonal antibody (MAb) and an anti-apo B MAb for the quantitative determination of Lp(a) in human serum. The assay is sensitive, precise and specific. Samples with different apo(a) isoforms had a linear response in a range of 3-70 mg/dl of Lp(a). Correlations between the ELISA and a commercial ELISA, an immunoradiometric assay and electroimmunodiffusion were 0.92, 0.96 and 0.98, respectively. The frequency distribution of Lp(a) concentration in blood donors showed the skew toward the right reported in other populations. Patients with angiographically assessed coronary atherosclerosis had three times higher levels of Lp(a) than those with no signs of coronary atherosclerosis.

Animals↗
PubMed1995

Conservative laparoscopic treatment of a posttraumatic splenic cyst.

Laparoscopy has recently been demonstrated to be a useful alternative to open surgery for the surgical treatment of spleen disorders, and it can also facilitate a conservative approach for treatment of selected spleen lesions. We present the laparoscopic spleen-preserving treatment of a post-traumatic spleen cyst. A 28-year-old female presented a mass in the left hypochondrium immediately after an uneventful pregnancy. CT revealed a splenic cyst of 10 x 8 cm. Laparoscopic exploration showed a cyst located in the lower pole of the spleen. All the cyst wall not covered by spleen tissue (70%) was excised, and the fragment of cyst wall was recovered through a bag. The patient recovered uneventfully and was discharged 72 hours later. The laparoscopic approach should be considered for evaluation and treatment of selected benign cystic lesions of liver, retroperitoneum or spleen origin.

Adult↗
PubMed1995

Somatic stability in chorionic villi samples and other Huntington fetal tissues.

We have studied different tissues from two affected fetuses with Huntington's disease (HD). In the first case the analysis was performed at 11 weeks of pregnancy; CAG repeats from seven different tissues were compared with the results obtained in the chorionic villi sample (CVS). We found 42 CAG repeats in all samples. In the second case the study was done at 12 weeks; eight tissues (including brain) were studied and compared with the CVS; in all of them, 44 CAG repeats were obtained. Our results show a somatic stability in the different analyzed tissues and suggest that mitotic instability can be a secondary consequence of neuronal degeneration and gliosis. Likewise, our data show great viability in the prenatal diagnosis (PD) of Huntington's disease using samples from any tissue.

Abortion, Therapeutic↗
PubMed1995

Construction and behavior of biologically contained bacteria for environmental applications in bioremediation.

The survival of microorganisms can be predicted through the use of active biological containment systems. We have constructed contained Pseudomonas putida strains that degrade alkylbenzoates. The modified strain carries a fusion of the Plac promoter to the gef gene, which encodes a killing protein. Expression from Plac is controlled through a regulatory cascade, so that Plac is switched on or off by the absence or presence of alkylbenzoates, respectively. Similar uncontained strains were also constructed and tested as a control. Contained and uncontained strains were genetically stable, and their survival and functionality in soil microcosms were as expected. Both contained and uncontained strains survived well in soils supplemented with alkylaromatics, whereas survival of the contained strain in soil microcosms without methylbenzoates was markedly reduced, in contrast to the control strain, which survived in these soils in the absence of alkylbenzoates. The TOL plasmid was transferred in soils between Pseudomonas strains but was not able to mobilize the elements of the containment system.

Bacteria↗
PubMed1995

Polymorphic variations in peripherin-RDS gene in the Spanish population.

The authors report a study of polymorphisms in the peripherin-RDS gene in 21 Spanish families affected with Autosomal Dominant Retinitis Pigmentosa and 56 unrelated normal individuals. We found 3 variants in first exon and nine variants in the third exon in an SSCP analysis, all corresponding to different previously described polymorphisms.

Base Sequence↗
PubMed1994

Biochemical evidence that the Saccharomyces cerevisiae THR4 gene encodes threonine synthetase.

In yeast, the assignment of the threonine synthetase activity to the THR4 gene has been inferred from different data, but never really proved enzymatically. In this work, an assay system for threonine synthetase activity in yeast crude extract is reported. The method is based on the quantification by reverse-phase high-performance liquid chromatography, of the threonine formed from O-phosphohomoserine. Using this method we have determined that this activity depends on the presence in the cell of an active form of the THR4 gene, thus demonstrating the univocal relationship between them.

Carbon-Oxygen Lyases↗
PubMed1994

Production of active, insect-specific scorpion neurotoxin in yeast.

A cDNA encoding the Androctonus australis Hector insect toxin 1 (AaH IT1) was expressed in yeast leading to secretion of fully biologically active protein. Three different multicopy plasmids were constructed using PCR. Expression was directed by the strong PGK1 promoter of the yeast vector pMA 91. Plasmid pMA 91-AaH IT1 encodes AaH IT1 and its own signal peptide. In the two other constructions, the cDNA encoding the mature part of AaH IT1 is fused to the prepro-signal sequence of the yeast alpha-mating-factor precursor; the pBAL 7-alpha-KREAEA-AaH IT1 includes the cDNA sequence encoding the KR(EAEA) processing sequence of the alpha-mating factor, and pBAL 7-alpha-KR-AaH IT1 encodes the KR fused directly to the AaH IT1 gene. The yeast alpha-mating-factor signal peptide launched the pro-alpha-mating-factor-AaH IT1 fusion protein into the secretory pathway. The fusion proteins are expected to be cleaved in the Golgi by the KEX2 endopeptidase and the STE13 dipeptidyl aminopeptidase, leading to release of mature AaH IT1. Pulse/chase labelling of transformed yeast protoplasts, followed by SDS/PAGE analysis of proteins immunoprecipitated from either the lysate or the extracellular fluid, showed that AaH IT1 was produced. The highest concentration of recombinant AaH IT1 in the culture medium, as determined using a 125I-AaH IT1 specific radioimmunoassay, was 4 micrograms/l (0.5 nM). The recombinant toxin was fully biologically active against cockroaches as assessed by injection and comparison to native AaH IT1. Moreover, it competed with radiolabelled native toxin for its receptor on the voltage-sensitive Na+ channel with a dissociation constant of 0.5 nM.

Animals↗
PubMed1994

Requirement of the propeptide for in vivo formation of active yeast carboxypeptidase Y.

Deletions have been constructed in the region encoding the 91-amino acid propeptide of the vacuolar enzyme carboxypeptidase Y of Saccharomyces cerevisiae, and in vivo effects of these mutations on the intracellular transport of the mutant proenzymes have been examined. Deletions did not include the vacuolar targeting signal, and none of the mutated forms of procarboxypeptidase Y was found to be secreted. All deletions, however, resulted in a decreased rate of transport of the truncated proenzymes from the endoplasmic reticulum to the Golgi apparatus. Up to 29 residues close to the N terminus can be removed without completely eliminating transport of the mutated proenzymes to the vacuole. However, the C-terminal part of the propeptide contains elements which are essential, since two small deletions, of 9 and 15 residues, respectively, within this area resulted in loss of carboxypeptidase Y activity. This region is, however, not sufficient for efficient formation of active carboxypeptidase Y, since truncated precursors in which the vacuolar targeting signal was fused to the C-terminal part of the proregion did not give rise to active enzyme. Based on the results, we propose that the carboxypeptidase Y propeptide plays an essential role in guiding the proper folding of the protein in vivo and that many parts of the propeptide contribute, in an additive way, to this function.

Alleles↗
PubMed1994

Dengue virus infects mouse cultured neurons but not astrocytes.

Cultures of mouse brain cells containing a high proportion either neurons or astrocytes were inoculated with various strains of dengue virus. At analysis by double immunofluorescence, all strains of dengue virus studied were tropic for neurons. In no case were the astrocytes infected. Only approximately 10% of all neurons were infected, suggesting that the virus may enter the cell through a membrane receptor present only in a subgroup of neurons.

Animals↗
PubMed1994

Identification of a novel rhodopsin mutation (Met-44-Thr) in a simplex case of retinitis pigmentosa.

Retinitis pigmentosa (RP) is a group of genetically heterogeneous retinal degenerations that can be autosomal dominant (ADRP), autosomal recessive (ARRP), or X-linked. Approximately 30% of ADRP patients show point mutations or small deletions in the rhodopsin gene. However, over 50% of the RP patients are simplex cases (sporadic). Screening for mutations in the rhodopsin gene of 33 patients with simplex RP by denaturing gradient gel electrophoresis (DGGE) was carried out. One patient, with D-type (diffuse) RP and consanguineous parents, showed an altered electrophoretic pattern for the 5' half of exon 1. Direct sequencing revealed a new mutation ATG to ACG in codon 44; this predicts a change of Met-44-Thr in rhodopsin. The position and amino acid substitution suggest that this mutation causes the RP phenotype. Implications for genetic counselling are discussed.

Adolescent↗
PubMed1994

Trinucleotide (CAG) repeat expansion in chromosomes of Spanish patients with Huntington's disease.

Huntington's disease (HD) is a neurodegenerative and hereditary disease characterized by progressive movement disorders and mental and behavioral abnormalities. The HD gene is an expanding and unstable trinucleotide repeat (CAG repeat sequences). We studied 77 individuals from 38 families with HD in an attempt to obtain information for genetic counselling and differential diagnosis. Our results indicate that individuals with more than 40 repeats will be affected by the disease, whereas those with fewer than 30 will be healthy. There can be some overlap between 30 and 40 repeats, and one should be careful when interpreting these results.

Adolescent↗
PubMed1994

Cytochemical and immunocytochemical study of nuclear structures of Lacandonia schismatica.

The interphase nucleus of the cells of several tissues of Lacandonia schismatica was studied using electron microscopy cytochemical and immunocytochemical methods. The EDTA staining procedure, preferential for RNP, contrasted the Lacandonia granules and perichromatin fibrils. These granules were found to be relatively resistant to RNAse hydrolysis, but they were easily digested if RNAse treatment was carried out after a short hydrolysis with pronase. Bismuth oxynitrate stained granular structures about 17 nm in diameter and the periphery of a few Lacandonia granules. The anti-snURNPs bound to RNP-containing fibrils in the perichromatin and interchromatin space and also to the periphery of some Lacandonia granules. Immunolabeling of DNA demonstrated numerous filaments of extended chromatin in the perichromatin and interchromatin spaces which were closely related to Lacandonia granules. These observations suggested that Lacandonia granules are equivalent to Balbiani ring granules of nuclei with polytene chromosomes and to perichromatin granules of other plant and animal nuclei. The small number of Lacandonia granules labeled in their periphery by anti-snURNP mAb were interpreted as being immature granules in the process of formation. The external or annular part of the ring-shaped structures is heavily labeled by anti-URNP mAbs but scarcely stained by the EDTA procedure. These features indicate that this region contains abundant proteins associated with snURNAs but probably little snURNAs. The synaptonemal-like complexes previously found in the interphase nuclei of Lacandonia are formed by two parallel masses of compact chromatin, which react with anti-DNA, and a central clear space crossed by fiber.(ABSTRACT TRUNCATED AT 250 WORDS)

Cell Nucleus↗