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Biomedical subjects

E Moreno

Publications and source records attributed to E Moreno.

At least 127 records · Page 7Linked to original sources
PubMed1997

Cotyledon thermal behavior and pectic solubility as related to cooking quality in common beans.

The characteristic of proteins, starch and pectic substances in cotyledons of two bean cultivars varying in cooking time were determined to investigate their possible contribution to bean cooking quality. Both cultivars showed the same enthalpies of starch gelatinization but different protein denaturation enthalpies. The proportion of hot water soluble pectins was higher in Michigan, the cultivar with the lower cooking time, than in Ojo de Cabra, the cultivar with the higher cooking time. These results were not due to differences in pectin methylation or in the ratio of monovalent to divalent cations in the tissue, suggesting that in fresh beans the beta-elimination reaction is not the sole or predominant route of thermal pectin degradation. Overall, this study indicates that varietal differences in bean cooking quality may be reflections of the rate of pectin loss during soaking/heating and that the thermal properties of starch and protein fractions seem to have a minor contribution. Researchers involved in this study propose that in fresh beans, the thermal pectin loss results from a two step mechanism: pectin enzymic breakdown during the bean soaking followed by thermal solubilization rather than beta-elimination during the bean heating.

Absorption↗
PubMed1997

Humanization of a mouse monoclonal antibody that blocks the epidermal growth factor receptor: recovery of antagonistic activity.

BACKGROUND: Antibody humanization by transplanting the complementarity determining regions (CDRs) of a murine antibody to a human framework aims to reduce the response of the human immune system against a foreign molecule. Frequently, however, some murine amino acids from the framework have to be retained to recover binding affinity. OBJECTIVES: To redesign R3, a mouse monoclonal antibody (mAb) that binds the human epidermal growth factor (EGF)-receptor and inhibits the binding of EGF, to be a human IgG1. STUDY DESIGN: The light and heavy chains of REI and Eu, respectively, were selected as human immunoglobulin (Ig) frameworks for CDR-grafting based on their high homology with the corresponding sequences of murine R3. Molecular modeling was used to analyze the possible effects of mutating murine residues that underlie the CDRs. RESULTS: CDR-grafting dramatically reduced the binding capability of the antibody. Molecular modeling suggested that two amino acids (Thr 76 and Thr 93), among five immunoglobulin heavy chain variable region (VH) residues underlying the CDRs, were critical for antigen binding. The five residues were mutated back to the original murine amino acids in different combinations contained in six variants of humanized antibodies. In agreement with molecular modeling analysis. The variant in which three murine residues were retained (Ser 75, Thr 76 and Thr 93) exhibited a similar capacity to inhibit the binding of 125I-labeled EGF to its receptor as compared with the original antibody. This humanized antibody was at least 2-fold less immunogenic in African Green monkeys than the chimeric antibody. CONCLUSIONS: Only very few mutations in the frameworks may be necessary to recover the binding capability of a humanized antibody. Molecular modeling can serve as a powerful tool to identify residues critical for binding.

Amino Acid Sequence↗
PubMed1997

Value of single oral loading dose of propafenone in converting recent-onset atrial fibrillation. Results of a randomized, double-blind, controlled study.

AIMS: To evaluate the efficacy and safety of a single loading oral dose of propafenone in the interruption of recent-onset atrial fibrillation. METHODS: After a complete medical history, physical examination, 12-lead ECG, chest X-ray, and routine biochemical laboratory testing, 55 consecutive patients with recent-onset atrial fibrillation were randomized double-blind in the emergency department for the administration of either a single oral dose (450 to 750 mg) of propafenone (29 cases) or a placebo (26 cases). After the 24-h observation period, comprehensive echocardiographic examination was performed. RESULTS: The groups were homogeneous as regards biological, clinical and echocardiographic characteristics. Two hours after treatment, 12 patients (41%) on propafenone but only two (8%) on placebo had converted to sinus rhythm (P = 0.005). This striking difference was maintained 6 h after treatment (65 vs 31%; P = 0.015) but lessened at 12 h (69% vs 42%; P = 0.060) and was insignificant at the end of the 24-h treatment period (79%, vs 73%; P = 0.752). Apart from hypotension, transient in three cases and sustained in one whose later echocardiographic examination demonstrated left systolic ventricular dysfunction, propafenone was well tolerated. CONCLUSION: Although there is no significant difference in the rates of conversion 24 h after treatment, propafenone works faster than placebo in achieving sinus rhythm. This rapid action of oral propafenone can be useful to solve quickly the clinical problems of a high proportion of patients arriving at the emergency department with acute atrial fibrillation.

Acute Disease↗
PubMed1997

Moderate concentrations of ethanol inhibit endocytosis of the yeast maltose transporter.

The maltose transporter in Saccharomyces cerevisiae is degraded in the vacuole after internalization by endocytosis upon nitrogen starvation in the presence of a fermentable substrate. This degradation, known as catabolite inactivation, is inhibited by the presence of moderate concentrations (2 to 6%, vol/vol) of ethanol. We have investigated the mechanism of this inactivation and have found that it is due to the inhibition of the internalization of the transporter by endocytosis. The results also indicate that this inhibition is due to alterations produced by ethanol in the organization of the plasma membrane which also affects to endocytosis of other plasma membrane proteins. Apparently, endocytosis is particularly sensitive to these alterations compared with other processes occurring at the plasma membrane.

Carrier Proteins↗
PubMed1997

[Intraoperative anesthetic management of kidney failure in adult liver transplantation. Conventional hemodialysis].

OBJECTIVE: To evaluate our application of indications, use and benefits of conventional hemodialysis during surgery in patients with advanced liver disease and acute or chronic renal failure undergoing liver transplantation (LP), liver retransplantation (LRT) or combined hepatorenal transplantation (CHRT). PATIENTS AND METHODS: We retrospectively reviewed the cases of 22 patients with advanced liver disease, 11 with acute renal failure and 11 with chronic renal failure. We performed 6 LT, 5 LRT and 11 CHRT. The following data were recorded in the periods before, during and immediately after surgery: metabolic, hemodynamic and coagulation parameters; bicarbonate, calcium and inotropic drug requirements; incidences during reperfusion of the graft; surgical technique used; and survival. RESULTS: Seven patients (32%) needed hemodialysis, 4 (18%) needed ultrafiltration, 7 (32%) needed both and 4 (18%) required neither. For 6 patients total clamping of the inferior vena cava (ICV) was required with external venovenous bypass. For 8 patients total clamping of the IVC was performed without venovenous bypass. For 8 others IVC clamping was partial with retrohepatic preservation (piggy-back). There were 2 deaths during surgery, 4 more within the first month after surgery and 4 more in the second month. Overall survival was 36.4% among acute patients and 72.7% among CHRT patients. CONCLUSIONS: 1) Conventional hemodialysis during surgery is feasible and gives good results; 2) conventional "high efficiency" hemodialysis is more effective and useful in these patients than is either slow, continuous hemodialysis or filtration; 3) the survival rate of CHRT patients is similar to that of patients undergoing LT with normal kidney function, and 4) partial IVC clamping in the anhepatic phase may decrease the need for ultrafiltration.

Adjuvants, Anesthesia↗
PubMed1997

Changes in phenotypes of apolipoprotein E and apolipoprotein(a) in liver transplant recipients.

The aim of this study has been to confirm that liver is the main site of apolipoprotein (apo) E and apo(a) synthesis, based in the changes of their phenotypes after transplantation. Apo E phenotypes were studied in 34 patients and apo(a) phenotypes in 27 of them before and after liver transplant. Thirteen patients changed the apo E phenotype after transplantation. Eight patients with E3/3 phenotype changed to the others with 2 or 4 alleles. Three patients with E4/3 phenotype changed to E3/3, one changed from E3/2 to E3/3 and another one changed from E4/2 to E3/2 phenotype after transplantation. Twenty one of the 27 patients changed the apo(a) phenotype. Thirteen of them also changed lipoprotein (Lp)(a) serum concentration at least twofold, showing in 11 an increase and in 2 a decrease, in relation with the change to phenotype associated with high and low Lp(a) concentration, respectively. Changes in apo E and apo(a) phenotypes in liver transplant recipients studied show that most of these apolipoproteins are synthesized by the liver.

Alleles↗
PubMed1997

When intracellular pathogens invade the frontiers of cell biology and immunology.

Cellular microbiology has recently been described as a new discipline emerging at the interface between cell biology and microbiology (Cossart et al., 1996). Many microbial pathogens can enter eukaryotic cells and live intracellularly either inside vacuoles or in the cytoplasm. The different steps during the invasion process are on the way of being dissected at the molecular level revealing new insights in basic cellular functions. Indeed, bacterial pathogenesis can help us to better understand the dynamics of cell cytoskeleton, intracellular membrane traffic and signal transduction events. The recent advancements in the field of microbial pathogenesis are creating a new cross-talk between cell biologists, microbiologists and immunologists. In this review, the different strategies used by several pathogens are presented and the mechanisms elaborated by host cells from the immune system to eliminate the parasites discussed.

Animals↗
PubMed1997

In search of a bacterial species definition.

The bacterial species concept was examined within the framework of plant and animal associated alpha-2 proteobacteria, taking into consideration the phylogenetic, taxonomic and biological approaches as well as the microbiologists' perception. The virtue of the phylogenetic approach is that it gives an evolutionary perspective of the bacterial lineage; however the methods used possess low resolution for defining species located at the terminal branches of the phylogenetic trees. The merit of the taxonomic approach is that species are defined on the basis of multiple characteristics allowing high resolution at the terminal branches of dendograms; its disadvantage is the inaccuracy in the earlier nodes. On an individual level, the qualitative biological characteristics used for the definition of species frequently reveal shortcomings because many of these properties are the result of coevolution, parallel evolution or the horizontal transfer of genes. Nevertheless, when considered together with the phylogenetic and taxonomic approaches, important uncertainties are discovered: these must be weighed if a practical definition of bacterial species is conceived. The microbiologists' perception is the criterion expressed by a group of sponsors who, based on scientific and practical grounds, propose a new bacterial species. The success of this new proposal is measured by its widespread acceptance and its permanence. A difficult problem concerned with defining bacterial species is how to distinguish if they are independent evolutionary units or if they are reticulate evolutionary units. In the first case the inherence is vertically transmitted as a result of binary fission and clonal expansion. This may be the case of some animal cell associated bacteria in which recombination appears to be precluded or exceptional. In the second case adaptive changes occurring within an individual can be horizontally transferred to many or all group members. This seems to be the condition of many intestinal and plant associated bacteria. Genetic drift and speciation in clonal bacteria will depend almost exclusively on mutation and internal genetic rearrangement processes, whereas speciation in reticulate bacteria will depend not only on these processes but in their genetic interactions with other bacterial strains. This uncertainty, which corresponds to the evolutionary process, is at the same time one of the key factors in defining a bacterial species.

Bartonella↗
PubMed1996

Visualization of gene expression in living adult Drosophila.

To identify genes involved in the patterning of adult structures, Gal4-UAS (upstream activating site) technology was used to visualize patterns of gene expression directly in living flies. A large number of Gal4 insertion lines were generated and their expression patterns were studied. In addition to identifying several characterized developmental genes, the approach revealed previously unsuspected genetic subdivisions of the thorax, which may control the disposition of pattern elements. The boundary between two of these domains coincides with localized expression of the signaling molecule wingless.

Animals↗
PubMed1996

[Validity of the protocol for evaluating the inappropriate use of hospitalization].

BACKGROUND: The study was carried out in order to assess the inter-observer reliability and validity in respect of clinical appraisal given by the Appropriateness Evaluation Protocol (AEP), in the context of the Spanish Public Hospital System. MATERIAL AND METHOD: In order to assess the reliability a total of 614 hospital stays chosen at random from 56 hospital admissions were independently analysed by three reviewers (two doctors and one nurse). In order to assess the validity, the findings obtained by the nurse were compared with the majority opinion given by the 7 hospital specialists in respect of each of hospital stays under evaluation. As part of the analytical procedure, indices for observed agreement, and specific agreement were calculated, as well as the Kappa statistic, all forming of various random samples of 614 hospital stays. In order to assess the predictive validity of the AEP, its sensitivity, specificity and predictive values were all measured against the majority clinical judgement. RESULTS: The study exhibited a high degree of inter-observer reliability (specific agreement > 64%, kappa > 0.75) and a reasonable validity in comparison with the consensus of opinions formed by a least 4 or 5 of its 7 clinical reviewers (specific agreement > 61%, kappa > 0.64), these values decreasing notably when the consensus of 6 or 7 of the reviewers was required. The AEP revealed a high degree of sensitivity and a low degree of specificity in comparison with the majority clinical assessment, thus minimising the occurrence of false results when the stay was regarded as appropriate, and producing false negatives (appropriate hospital stays regarded as inappropriate) varying in degree from moderate to very high. CONCLUSIONS: The results showing high reliability and moderate validity regarding clinical assessment shows the AEP to be a useful instrument in the sifting-out of inappropriate use of hospitalisation, although they do not allow a definitive judgement to be made concerning the efficiency of hospital services nor judgements regarding individual cases.

Evaluation Studies as Topic↗
PubMed1996

Septate uterus with cervical duplication and longitudinal vaginal septum: a report of three new cases.

The first case of a rare mullerian anomaly characterized by the presence of a complete uterine septum with duplication of the cervix and a longitudinal vaginal septum has been reported very recently. We present here three new cases of such an anomaly in an attempt to alert gynaecologists to the possible occurrence of such a malformation. The cases challenge the classical views of unidirectional (caudad to cranial) mullerian development and support the alternative embryologic hypothesis of Muller et al. according to which fusion and resorption begins at the isthmus and proceeds simultaneously in both the cranial and caudal directions.

Adult↗
PubMed1996

Randomized trial of fluconazole versus nystatin for the prophylaxis of Candida infection following liver transplantation.

A prospective, randomized, multicenter study addressed the safety and efficacy of fluconazole therapy in 143 liver transplant patients. Seventy-six patients received daily oral fluconazole (100 mg), and 67 received nystatin (4 X 10(6) U) during the first 28 days after transplantation. Candida colonization occurred in 25% and 53% of patients in the fluconazole and nystatin groups, respectively (P = .04), and 13% and 34% of patients in the respective groups had Candida infections (P = .022). Of these patients, 10.5% in the fluconazole group and 25.3% in the nystatin group had superficial candidal infections (P = .024). Invasive candidiasis developed in 2 patients in the fluconazole group (2.6%) and 6 in the nystatin group (9.0%) (P = .12). There was no increased hepatotoxicity, cyclosporine interaction, or emergence of clinically relevant resistant Candida strains attributable to fluconazole. Thus, oral fluconazole (100 mg) is safe and reduces Candida colonization and infection after liver transplantation.

Adult↗
PubMed1996

Brucella-Salmonella lipopolysaccharide chimeras are less permeable to hydrophobic probes and more sensitive to cationic peptides and EDTA than are their native Brucella sp. counterparts.

A rough (R) Brucella abortus 45/20 mutant was more sensitive to the bactericidal activity of polymyxin B and lactoferricin B than was its smooth (S) counterpart but considerably more resistant than Salmonella montevideo. The outer membrane (OM) and isolated lipopolysaccharide (LPS) of S. montevideo showed a higher affinity for these cationic peptides than did the corresponding B. abortus OM and LPS. We took advantage of the moderate sensitivity of R B. abortus to cationic peptides to construct live R B. abortus-S-LPS chimeras to test the activities of polymyxin B, lactoferricin B, and EDTA. Homogeneous and abundant peripheral distribution of the heterologous S-LPS was observed on the surface of the chimeras, and this coating had no effect on the viability or morphology of the cells. When the heterologous LPS corresponded to the less sensitive bacterium S B. abortus S19, the chimeras were more resistant to cationic peptides; in contrast, when the S-LPS was from the more sensitive bacterium S. montevideo, the chimeras were more susceptible to the action of peptides and EDTA. A direct correlation between the amount of heterologous S-LPS on the surface of chimeric Brucella cells and peptide sensitivity was observed. Whereas the damage produced by polymyxin B in S. montevideo and B. abortus-S. montevideo S-LPS chimeras was manifested mainly as OM blebbing and inner membrane rolling, lactoferricin B caused inner membrane detachment, vacuolization, and the formation of internal electron-dense granules in these cells. Native S and R B. abortus strains were permeable to the hydrophobic probe N-phenyl-1-naphthylamine (NPN). In contrast, only reduced amounts of NPN partitioned into the OMs of the S. montevideo and B. abortus-S. montevideo S-LPS chimeras. Following peptide exposure, accelerated NPN uptake similar to that observed for S. montevideo was detected for the B. abortus-S. montevideo LPS chimeras. The partition of NPN into native or EDTA-, polymyxin B-, or lactoferricin B-treated LPS micelles of S. montevideo or B. abortus mimicked the effects observed with intact cells, and this was confirmed by using micelle hybrids of B. abortus and S. montevideo LPSs. The results showed that LPS is the main cause of B. abortus' resistance to bactericidal cationic peptides, the OM-disturbing action of divalent cationic chelants, and OM permeability to hydrophobic substances. It is proposed that these three features are related to the ability of Brucella bacteria to multiply within phagocytes.

Anti-Bacterial Agents↗
PubMed1996

Characterization of Brucella abortus and Brucella melitensis native haptens as outer membrane O-type polysaccharides independent from the smooth lipopolysaccharide.

Brucella native haptens (NHs) extracted with hot water from smooth (S)-type B. abortus and B. melitensis were purified to high levels of serological activity and compared with the polysaccharide obtained by acid hydrolysis (PS) of the S lipopolysaccharide (S-LPS). By 13C nuclear magnetic resonance analysis, NHs showed the spectrum of a homopolymer of alpha-1,2- or alpha-1,2- plus alpha-1,3-linked 4-formamido-4,6-dideoxy-D-mannose (N-formylperosamine) previously reported for the LPS O chain. However, while PS contained up to 0.6% 3-deoxy-D-manno-2-octulosonate, this LPS-core marker was absent from NH. High performance liquid chromatography and thin-layer chromatography showed heterogeneity in NH purified from whole cells but not in PS. By immunoprecipitation, polysaccharides indistinguishable from NH were demonstrated in extracts obtained with phenol-water, saline at 60 degrees C, and ether-water treatments, and none of these treatments caused S-LPS hydrolysis detectable with antibodies to the O chain and lipid A. Two lines of evidence showed that NH was in the cell surface. First, NH became biotinylated when B. abortus live cells were labelled with biotin-hydrazide, and the examination of cell fractions and electron microscopy sections with streptavidin-peroxidase and streptavidin-coloidal gold, respectively, showed that labelling was extrinsic. Moreover, whereas only traces of NH were found in cytosols, the amount of NH was enriched in cell envelopes and in the outer membrane blebs spontaneously released by brucellae during growth. Interactions between NH and S-LPS were observed in crude cell extracts, and such interactions could be reconstituted by using purified NH and LPS. The results demonstrate that NH is not a hydrolytic product of S-LPS and suggest a model in which LPS-independent O-type polysaccharides (NH) are intertwined with the O chain in the outer membrane of S-type brucellae.

Brucella abortus↗
PubMed1996

Epidemiology of Taenia solium taeniasis and cysticercosis in two rural Guatemalan communities.

Taenia solium taeniasis and cysticercosis are known to be endemic in Guatemala but no studies had been undertaken in rural communities where transmission was thought to occur. Two adjacent communities, Quesada and El Jocote, in the Department of Jutiapa were selected. The former had considerably better sanitary infrastructure than the latter. The seroprevalence of antibodies detected in humans by immunoblot to T. solium metacestode glycoprotein antigens was 10% and 17% and the prevalence of intestinal taeniasis was 1% and 2.8% in the two villages, respectively. Both of these represented statistically greater rates in El Jocote. Females were significantly more likely to be seropositive than males in the study as a whole. The majority of cases of intestinal taeniasis were due to T. solium. Cases of intestinal taeniasis were significantly more likely to be anti-cysticercus antibody-positive than the general population. Epilepsy was recorded in 2.8% and 2.9% of the populations of Quesada and El Jocote, respectively. Follow-up of this group and a group of asymptomatic individuals by computed tomography scan indicated that individuals with a history of seizures had a higher rate of abnormalities suggestive of neurocysticercosis. Cysts were present in the tongues of 4% of live pigs sampled in Quesada and 14% in El Jocote. In these two communities, which are probably representative of many others in Guatemala, T. solium appeared to be a significant public health problem.

Adult↗
PubMed1996

Morphological and morphometric study of early changes in the ageing golden hamster testis.

The histological and morphometric features of the aged golden hamster testis were examined and compared with those of adult animals. Three age groups (6, 12 and 18 months) were studied by light microscopy, and testosterone levels were determined. The observations showed a progressive involution of the seminiferous tubules, beginning to be perceptible at 12 months with slight hypospermatogenesis and desquamation. In 18-month-old specimens degeneration was more significant and histopathological lesions could be classified on a 6-point scale, ranging from slight hypospermatogenesis to absence of germ cells. These involutive changes were not homogeneously distributed in the testis; affected tubules close to seeming normal ones were present. The morphometric results point to a progressive diminution, in the 3 age groups, in vas deferens spermatozoa, pachytene spermatocytes, and Sertoli and Leydig cells (the latter significantly diminished only in the 18-month-old group). For morphometric purposes a 7-point scale of tubule degeneration was used, showing a significant increase, with age, in the presence of more degenerated tubule stages. Several correlations were found between the morphometric variables, outlining existing relations between age and the associated diminution of several testis cell types, and lumen diameter. No significant differences were found between groups in serum testosterone levels. In conclusion, histological changes related to age are evident in 18-month-old animals, while at 12 months a diminution in germ cell numbers and sperm production is detectable.

Aging↗
PubMed1996

Effect of adjuvants on the antibody response of mice to Bothrops asper (Terciopelo) snake venom.

The adjuvant properties of several immunostimulant molecules on the murine antibody response to Bothrops asper snake venom were evaluated. Mice receiving venom together with either sodium alginate, calcium alginate, aluminum hydroxide, muramyl dipeptide, killed Brucella abortus or B. abortus smooth lipopolysaccharide developed a similar antibody response. Despite the fact that in some cases animals injected with venom and Salmonella montevideo lipopolysaccharide developed a significantly higher antibody titer when compared to other experimental groups, no statistically significant differences were observed in most of the comparisons.

Adjuvants, Immunologic↗