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Biomedical subjects

J Moreno

Publications and source records attributed to J Moreno.

At least 91 records · Page 5Linked to original sources
PubMed1999

C172S substitution in the chloroplast-encoded large subunit affects stability and stress-induced turnover of ribulose-1,5-bisphosphate carboxylase/oxygenase.

Previous work has indicated that the turnover of chloroplast ribulose-1,5-bisphosphate carboxylase/oxygenase (Rubisco; EC 4.1.1. 39) may be controlled by the redox state of certain cysteine residues. To test this hypothesis, directed mutagenesis and chloroplast transformation were employed to create a C172S substitution in the Rubisco large subunit of the green alga Chlamydomonas reinhardtii. The C172S mutant strain was not substantially different from the wild type with respect to growth rate, and the purified mutant enzyme had a normal circular dichroism spectrum. However, the mutant enzyme was inactivated faster than the wild-type enzyme at 40 and 50 degrees C. In contrast, C172S mutant Rubisco was more resistant to sodium arsenite, which reacts with vicinal dithiols. The effect of arsenite may be directed to the cysteine 172/192 pair that is present in the wild-type enzyme, but absent in the mutant enzyme. The mutant enzyme was also more resistant to proteinase K in vitro at low redox potential. Furthermore, oxidative (hydrogen peroxide) or osmotic (mannitol) stress-induced degradation of Rubisco in vivo was delayed in C172S mutant cells relative to wild-type cells. Thus, cysteine residues could play a role in regulating the degradation of Rubisco under in vivo stress conditions.

Amino Acid Substitution↗
PubMed1999

Effect of different inhaled bronchodilators on recovery from methacholine-induced bronchoconstriction in asthmatic children.

Two hundred fourteen children with mild to moderate asthma were studied to determine bronchodilator effects 5 min after administration of five different metered dose inhaler (MDI) aerosol formulations available in our country, and results were compared to placebo. Methacholine bronchial challenge was performed by the tidal breathing method, using increasing concentrations until a fall in forced expired volume in 1 s (FEV(1)) >/=20% was achieved (PC20). Immediately after FEV(1) had fallen 20% or more, children were randomly allocated into 1 of 6 groups to receive: salbutamol 200 microg (S), fenoterol 200 microg (F), salbutamol 200 microg + beclomethasone 100 microg (S + B), fenoterol 200 microg + ipratropium bromide 80 microg (F + IB), salmeterol 50 microg (SM), and placebo (P). The bronchodilator effect was determined by measuring FEV(1) 5 min after inhalation of medications. Nonparametric tests were used for statistical analysis. The six groups were similar in anthropometric and in respiratory characteristics. All five inhaled aerosols containing beta-agonists caused a significant bronchodilator effect as compared to placebo. However, the effect was significantly greater in the groups treated with F or F + IB (P < 0.05) compared to other formulations. We conclude that the five types of aerosols used in this study are able to reverse methacholine-induced bronchoconstriction 5 min after inhalation of a bronchodilator.

Administration, Inhalation↗
PubMed1999

Endogenous and exogenous forms of the same antigen are processed from different pools to bind MHC class II molecules in endocytic compartments.

The current studies were carried out to examine the basis for the differences in the antigenic peptides generated from exogenous and endogenous forms of hen egg white lysozyme (HEL). The role of different intracellular compartments in the generation and binding of HEL peptides derived from two endogenous forms of HEL, either secreted (sHEL) or retained in the endoplasmic reticulum (ER, KDELHEL), presented by MHC class II molecules was examined and compared to exogenous HEL. Initially it was found that antigen-presenting cells bearing both intracellular forms of HEL generated and presented a number of IAk-restricted HEL epitopes to T cell hybridomas, although sHEL was processed more efficiently than KDEL-HEL. There were differences, however, for some determinants between endogenous and exogenous HEL. At equivalent antigen-presenting efficiencies, endogenous HEL-bearing cells displayed a lower surface density of IAk-bound HEL-52-61-related peptides than cells pulsed with exogenous HEL, as detected by a specific monoclonal antibody. Neither endogenous HEL degradation nor peptide binding to MHC class II molecules occurred in the ER. Processing of sHEL and KDELHEL appears to take place either in a post-trans-Golgi network acidic compartment or in the cytosol, whereas peptide binding to MHC class II molecules occurs in endocytic compartments. Furthermore, the peptides generated were derived from an endogenous source rather than from secreted and re-endocytosed HEL. Thus, processing of endogenous HEL is from a different pool than exogenous HEL and occurs in different compartments.

Animals↗
PubMed1999

S-adenosylmethionine in alcoholic liver cirrhosis: a randomized, placebo-controlled, double-blind, multicenter clinical trial.

BACKGROUND/AIM: The efficacy of S-adenosylmethionine (AdoMet) in the treatment of liver cell injury has been demonstrated in several experimental models. The aim of this study was to investigate the effects of AdoMet treatment in human alcoholic liver cirrhosis. METHODS: A randomized, double-blind trial was performed in 123 patients treated with AdoMet (1200 mg/day, orally) or placebo for 2 years. All patients had alcoholic cirrhosis, and histologic confirmation of the diagnosis was available in 84% of the cases. Seventy-five patients were in Child class A, 40 in class B, and 8 in class C. Sixty-two patients received AdoMet and 61 received placebo. RESULTS: At inclusion into the trial no significant differences were observed between the two groups with respect to sex, age, previous episodes of major complications of cirrhosis, Child classification and liver function tests. The overall mortality/liver transplantation at the end of the trial decreased from 30% in the placebo group to 16% in the AdoMet group, although the difference was not statistically significant (p = 0.077). When patients in Child C class were excluded from the analysis, the overall mortality/liver transplantation was significantly greater in the placebo group than in the AdoMet group (29% vs. 12%, p = 0.025), and differences between the two groups in the 2-year survival curves (defined as the time to death or liver transplantation) were also statistically significant (p = 0.046). CONCLUSIONS: The present results indicate that long-term treatment with AdoMet may improve survival or delay liver transplantation in patients with alcoholic liver cirrhosis, especially in those with less advanced liver disease.

Double-Blind Method↗
PubMed1999

Analysis of polysaccharides in cider: their effect on sensory foaming properties.

A feasible spectrophotometric method for determining acidic and neutral polysaccharides in cider is described, and the advantages of this method are examined with respect to precision, accuracy, and detection and quantitation limits. The concentration of nonvolatile and volatile components in cider, together with chemometric techniques such as principal component analysis (PCA), soft independent modeling of class analogy (SIMCA), and partial least squares (PLS), allowed us to typify the ciders on the basis of their foaming properties. Acidic polysaccharide and 1-propanol were the most relevant variables for this purpose.

Beverages↗
PubMed1999

Isoenzyme electrophoresis of Rhodnius species: a phenetic approach to relationships within the genus.

Seventeen samples of Rhodnius, representing at least eight different species according to their morphological characteristics, were submitted to multilocus isoenzyme electrophoresis, revealing 17 different loci. A phenetic analysis of the enzyme data not only clustered the species in accordance with their geographical origin but also revealed interspecific relationships that differed from those expected from the morphology.

Animals↗
PubMed1999

Decreased serum ubiquinone-10 concentrations in phenylketonuria.

BACKGROUND: Ubiquinone-10 is a lipid with important metabolic functions that may be decreased in phenylketonuria (PKU) because patients with PKU consume diets restricted in natural proteins. OBJECTIVE: We studied serum ubiquinone-10 concentrations in PKU patients. DESIGN: This was a retrospective, transversal study in which we compared serum ubiquinone-10, plasma cholesterol, plasma tyrosine, and plasma phenylalanine concentrations in 43 PKU patients with concentrations in a reference population (n = 102). Serum ubiquinone-10 concentrations were analyzed by HPLC with ultraviolet detection. Plasma tyrosine and phenylalanine were measured by ion-exchange chromatography. RESULTS: Serum ubiquinone-10 concentrations in PKU patients were significantly lower than in the reference population (P < 0.01 for patients aged 1 mo to <8 y and P < 0.00005 for patients aged 8-33 y). Moreover, 5 of 18 PKU patients (28%) in the younger age group and 10 of 23 (43%) in the older age group had serum ubiquinone-10 concentrations below the reference interval. CONCLUSIONS: Serum ubiquinone-10 deficiency appears to be related to the restricted diet of PKU patients. Because serum ubiquinone-10 plays a major antioxidant role in the protection of circulating lipoproteins, the correction of ubiquinone-10 concentrations should be considered in PKU patients. Further investigation seems advisable to elucidate whether the deficiency in serum ubiquinone-10 status is clinically significant.

Adolescent↗
PubMed1999

The 5S rRNA is associated with Ro60 ribonucleoprotein and is co-precipitated with hYRNAs by anti-Ro antibodies.

Ro particles are conserved molecules that contain a YRNA and various Ro proteins, which are recognized by autoimmune sera from patients with lupus erythematosus or Sjögren's syndrome. The Ro60 ribonucleoprotein (RNP) forms complexes with certain 5S rRNAs, in such a manner that Ro60 could participate in the control of 5S rRNA production. The present studies were carried out to explore the interaction of Ro components, and to address the question whether Ro60 RNP binds simultaneously 5S rRNA and hYRNA. Anti-Ro60 antibodies were used to immunoprecipitate the RNA. Immunoprecipitates were reverse transcribed with specific oligonucleotides and the resulting cDNAs from 5S and hY4 were amplified by PCR. We found that 5S rRNA is complexed with hY4 and hY5 RNAs by means of the Ro60 RNP. Moreover, by in situ hybridization assays we were able to demonstrate that these molecules have a similar nuclear distribution. According to these results, it seems reasonable to assume that the Ro60 protein could be involved in ribosome assembly.

Antibodies, Monoclonal↗
PubMed1999

Genetic structure and phylogenetic relationships of Colombian Trypanosoma cruzi populations as determined by schizodeme and isoenzyme markers.

Twenty-four Trypanosoma cruzi stocks isolated from vectors and from human and Didelphis marsupialis hosts from highly separated sylvatic localities in Colombia were characterized by isoenzyme and schizodeme analyses. The stocks were collected primarily from sylvatic ecotopes representing areas of low, moderate, and high endemicity for Chagas' diseases in Colombia. Parasites were characterized mainly by schizodeme analysis with the restriction enzyme Eco RI and the isoenzyme analysis was performed at 10 genetic loci. These analyses demonstrated an agreement between the classifications based on the isoenzyme analysis and on the restriction fragment length polymorphism patterns obtained with the Colombian stocks. There is clear evidence of demic subdivision between the eastern (E) and western (W) stocks separated by the Andean Mountains and Magdalena River, which is likely due to the geographic isolation generated by these topographic features. Heterozygosity estimates indicate that the E group could be more ancient than the W group. As was postulated in a previous study, these results are also compatible with the existence of a clonal population structure in Colombian sylvatic T. cruzi. Evidence presented here failed to demonstrate a correlation between the degree of endemy and genetic clustering. Finally, schizodeme and isoenzymatic analyses comparing Colombian T. cruzi stocks with others from Chile confirm that Colombian isolates are genetically related to zymodeme 1 and distant from zymodeme 2.

Animals↗
PubMed1999

Parental origin and meiotic stage of non-disjunction in 139 cases of trisomy 21.

The parental origin and the meiotic stage of non-disjunction have been determined in 139 Down syndrome patients with regular trisomy 21 and in their parents through the analysis of DNA polymorphism. The meiotic error is maternal in 91.60% cases and paternal in 8.39% of cases. Of the maternal cases, 72.41% were due to meiosis I errors (MMI) and 27.58% were due to meiosis II errors (MMII). Of the paternal cases, 45.45% were due to meiosis I (PMI) and 54.54% were due to meiosis II (PMII). The mean maternal ages were 31.6 +/- 5.3 (+/- SD) years in errors from MMI, 32.3 +/- 6.4 years in errors from MMII, 31.4 +/- 4.6 years in errors from PMI and 29.5 +/- 2.7 years in errors from PMII. No significant statistical differences were observed between maternal and paternal errors, further supporting the presence of a constant chromosome 21 non-disjunction error type.

Adolescent↗
PubMed1999

[High-frequency oscillatory ventilation as salvage strategy in the newborn infant. Spanish multicenter study. I].

OBJECTIVE: The aim of this study was to evaluate the results of high frequency ventilation (HFV) used as a rescue strategy in newborn infants with severe lung disease who either failed conventional mechanical ventilation (CMV) or had an air block. PATIENTS AND METHODS: From April 1995 to June 1998, 241 infants with severe lung disease and managed according to a common protocol of HFV used as a rescue strategy were prospectively evaluated in the nine participating level III Spanish Neonatal Intensive Care Units. The most frequent diagnoses were respiratory distress syndrome (119), meconium aspiration (24), pneumonia (19) and congenital diaphragm hernia (18). RESULTS: Mean +/- SD gestational age and birth weight were 32.0 +/- 5.5 weeks and 1,187 +/- 1,071 g, respectively. All babies were previously manages with CMV for a mean of 59 hours. HFV was started at a mean postnatal age of 82 hrs, with a mean oxygenation index (OI) of 28.3 +/- 15.3 and an a/A DO2 of 0.10 +/- 0.08. Initial mean HFV settings were: mean airway pressure 12.8 +/- 3.4 mbar, frequency 8.3 +/- 1.4 Hz, amplitude 53 +/- 20 percent, tidal volume 2.2 +/- 0.7 ml/kg and FiO2 0.88 +/- 0.2. At two hours of HFV there was a significant increase in the mean PaO2 (from 48 to 80 mmHg), with a concomitant decrease in FiO2 (from 0.88 to 0.79), PaCO2 (from 60 to 46 mmHg) and OI (from 28 to 18). Mean a/A DO2 increased from 0.10 to 0.19; these changes remained similar thereafter. HFV was suspended after a mean of 95 hrs because of improvement in 70%, death in 19% and failure to improve the clinical condition in the remaining 19%. Intrahospital death rate was 32%. The following complications were observed: pneumothorax (10%), interstitial emphysema (4%), intraventricular hemorrhage grades III and IV (14.5%) and bronchopulmonary dysplasia (35%). CONCLUSIONS: HFV is an effective rescue strategy that improves pulmonary gas exchange within two hours of its initiation.

Female↗
PubMed1999

Effect of antiinflammatory drugs on COX-1 and COX-2 activity in human articular chondrocytes.

OBJECTIVE: To study the effect of steroidal and nonsteroidal antiinflammatory drugs (NSAID) on cyclooxygenase (COX-1 and COX-2) activity in human articular chondrocytes. METHODS: Chondrocytes were isolated from articular cartilage of donors with no articular disease. Unstimulated and interleukin 1 (IL-1) stimulated chondrocytes were used as models to study the effects of drugs on COX-1 and COX-2. Cells were incubated with vehicle or drugs; supernatants were removed and the level of prostaglandin E2 (PGE2) in each sample was determined by enzyme immunoassay. IC50 were calculated from the reduction in PGE2 content by different concentrations of the test substance by linear regression analysis. RESULTS: COX- mRNA was detected in unstimulated cells, but stimulation with IL-1 for up 12 h did not modify the levels of COX-1 mRNA. In contrast, COX-2 mRNA was not detectable in unstimulated cells, but it was induced by IL-1. Dexamethasone inhibited COX-2 mRNA expression induced by IL-1. COX-2 protein levels correlated with mRNA expression. Dexamethasone was the strongest drug inhibitor of COX-2 (IC50 = 0.0073 microM). However, it did not inhibit COX-1 activity. Among all NSAID tested, meloxicam and aspirin were the least potent inhibitors of COX-1 (IC50 = 36.6 microM and 3.57 microM, respectively). Indomethacin and diclofenac were the most potent inhibitors of COX-1 (IC50 = 0.063 microM and 0.611 microM, respectively) and COX-2 isoforms (IC50 = 0.48 microM and IC50 = 0.63 microM, respectively). Meloxicam was a more potent inhibitor of COX-2 (IC50 = 4.7 microM) than aspirin (IC50 = 29.3 microM) and similar to piroxicam (IC50 = 4.4 microM). Among all drugs tested dexamethasone showed the greatest selectivity for COX-2 and meloxicam was the NSAID with the best COX-2/COX-1 ratio (r = 0.12). Aspirin and piroxicam were about 8 times more active against COX-1 than COX-2, indomethacin was 7 times more active, and diclofenac was an equipotent inhibitor of COX-1 and COX-2. CONCLUSION: We found that COX-1 and COX-2 isoforms are expressed in human chondrocytes at rest and in IL-1 stimulated cells, respectively. Antiinflammatory drugs have different capacities to inhibit COX enzyme in human articular chondrocytes.

Anti-Inflammatory Agents, Non-Steroidal↗
PubMed1999

Genetic variability of Colombian populations of Trypanosoma cruzi and Trypanosoma rangeli.

This paper presents our study of genetic variability of Trypanosoma cruzi and Trypanosoma rangeli strains isolated from different Colombian biological hosts, using multilocus enzyme electrophoresis for 15 enzyme systems and electrophoretic analysis of kinetoplast DNA (kDNA) digested with EcoRI and MspI endonucleases. Isoenzyme profiles were used to determine genotypes for each of the strains. Populations of T. cruzi and T. rangeli were found to have a polymorphic average of 86.7% and 26.7%, respectively. Schyzodeme analysis showed high variability for T. cruzi, since its genetic distance values were found to be greater than 50%, considerably higher than those previously reported for several T. cruzi strains from other countries. These results suggest that Colombian strains should be considered as genetically independent entities and are worth studying independently from each other to clearly establish their biological and clinical characteristics.

Animals↗
PubMed1999

[Open clinical trial with oral acyclovir for the prophylaxis of disease by Cytomegalovirus in low risk liver transplant recipients].

OBJECTIVE: Checking the first 70 low risk liver transplantation performed in our hospital, who did not receive prophylaxis for Cytomegalovirus, we found that the incidence of Cytomegalovirus-infection and Cytomegalovirus-disease were 47% and 16% respectively. METHODS: For this reason we started a prospective, open clinical study, to address the safety of acyclovir prophylaxis in low-risk liver transplant patients. Seventy patients did not receive acyclovir. Fifty patients received oral acyclovir during 3 months (800-3,200 mg/day). RESULTS: The occurrence of Cytomegalovirus infection was not modified (40%) but Cytomegalovirus disease decreased dramatically (4%, p < 0.01) during the first year after transplantation. Acyclovir was well tolerated. The incidence of leukopenia and renal failure were similar in both groups. Acyclovir did not improved the global survival of patients. CONCLUSIONS: Thus, oral acyclovir does not reduce Cytomegalovirus infection although it is efficient and safe in the prevention of Cytomegalovirus disease in low-risk liver transplantation, and prevents Herpes-simplex and Varicela-zoster symptomatic disease in this group of patients.

Acyclovir↗
PubMed1999

[Acyclovir may modulate clonal expansion of cd8+ lymphocytes induced by the Cytomegalovirus antigen].

BACKGROUND: Although the potent antiviral effect of acyclovir on the Herpes-simplex (HSV) and Varicela-zoster (VZV) virus and the scarce effectiveness versus Cytomegalovirus (CMV) is known, some data suggest that it may have an immunodulator implicated in the control of these viral disease. The aim of this study was to characterize this possible effect of acyclovir versus the CMV antigen. METHODS: We stimulated cultures of mononuclear cells obtained in 7 healthy patients who were seropositive for CMV and HSV with CMV antigen, HSV and with phitohemaglutinine (PHA). The proliferation index and culture cell phenotype were later determined in the absence and presence of acyclovir (2 micrograms/ml). In another group the proliferation index and cell phenotype following stimulation with the CMV antigen were studied prior to and after treating the same volunteers with acyclovir for one week (800 mg/6h). RESULTS: The CMV antigen and HSV induced T cell proliferation predominantly involving the CD8+ subpopulation leading to an inversion of the CD4/CD8 quotient. On addition of acyclovir to the cell culture a moderate reduction was produced in lymphoproliferative response versus the CMV antigen and HVS, characteristically modulating CD8+ cell proliferation, thereby leading to reestablishment of the CD4/CD8 quotient. However, the proliferation induced by PHA was not inhibited. These results were produced on oral administration of acyclovir. CONCLUSIONS: Acyclovir modulates the lymphoproliferative response induced by CMV antigen. Based on this observation, the authors hypothesize that this immunomodulation may be related to its preventive effect on CMV disease in transplanted patients.

Acyclovir↗
PubMed1998

Updating protections for human subjects involved in research. Project on Informed Consent, Human Research Ethics Group.

For decades, all federally funded research involving human subjects has been subject to regulations that require the informed consent of the subject and oversight by the local institution. These regulations last underwent major revision in 1981 and have remained unchanged despite significant changes in the nature of clinical science, the financial sources of research support, and the institutional environment in which clinical research is conducted. In the intervening years, doubt has evolved as to whether the regulations currently in place adequately protect the welfare and rights of research subjects in today's clinical research environment and whether the costs, in terms of time, bureaucracy, and delay, are justified by the level of protection afforded. The Human Research Ethics Group, administered by the Center for Bioethics at the University of Pennsylvania Health System, extensively reviewed the status of existing human subjects protections with the aim of making recommendations to improve and reform the regulations. Here, we present recommendations constituting a consensus of the group members for reform in 3 key areas: protecting subject populations with special needs and vulnerabilities, oversight by institutional review boards, and regulatory policy.

Advisory Committees↗
PubMed1998

Appearance and development of lymphoid cells in the chicken (Gallus gallus) caecal tonsil.

BACKGROUND: We have analyzed by electron microscopy, immunohistochemistry, and flow cytometry the development of chicken caecal tonsil, the largest lymphoid organ of avian gut-associated lymphoid tissue (GALT). METHODS: White Leghorn chickens of different ages obtained from a local supplier were routinely processed by transmission electron microscopy. For both immunohistochemistry and flow cytometry, we tested a battery of specific monoclonal antibodies (mAbs) to chicken cell markers on caecal cryosections or cell suspensions, respectively. RESULTS: A rudimentary caecal tonsil occurs at the end of incubation. The organ grows just after birth, reaching the adult condition 4 days later. Firstly (4 days to 2 weeks), it contains predominantly T lymphocytes, principally TcR alphabeta+ and CD4+ cells, which occupy largely the named caecal diffuse lymphoid tissue. In adult tonsils (6-week-old chickens) however, B lymphocytes, mainly expressing either IgM or IgA, predominate. They occur in both the subepithelial zone and the germinal centers, in which there are also a few T cells. After 2 weeks the CD8+ lymphocytes gradually become more numerous than CD4+ cells. In the tonsillar epithelium CD8+TcRgammadelta+ T cells, CD8+TcRgammadelta-alphabeta-, presumably NK cells, and a few B lymphocytes are the main cell subpopulations. CONCLUSIONS: Chicken caecum grows fast after hatching. The diffuse lymphoid tissue largely contains TcR alphabeta CD4+ or CD8+ cells. CD8+ cells of caecal epithelium represent gammadelta T cells or NK cells. B lymphocytes which occur in the subepithelial zone, germinal centers, and, in few numbers, the caecal epithelium predominantly express either IgM or IgA.

Animals↗