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G Moreno

Publications and source records attributed to G Moreno.

At least 37 records · Page 2Linked to original sources
PubMed1999

[Respiratory pasteurellosis. Description of a first series in Spain].

OBJECTIVE: To know the clinical and microbiological characteristics of a first series of 8 patients in whom Pasteurella multocida was detected in samples from low respiratory airways. PATIENTS AND METHODS: Patients with respiratory disease who had positive cultures for P. multocida in several biologic samples between 1986 and 1998 were studied. Patient's data were obtained from clinical files; microbiological study included microscopic examination, qualitative culture in all samples and quantitative culture in low respiratory airway samples. RESULTS: P. multocida was detected in 7 males and one female, with a mean age of 63 years (range: 6-71). All but one had a previous bronchial disease: 5 had chronic obstructive bronchial disease, 2 had bronchiectasis and one had relapsing acute bronchitis. Three patients referred a previous contact with pets. The main diagnosis, at the time P. multocida was detected, was exacerbated bronchitis in 4 patients, pneumonia in 2 (one with sepsis and positive blood culture to P. multocida) and another one with empyema. In the only paediatric patient P. multocida was a casual finding. Two patients died, both having a severe immunosuppression. The percentage of P. multocida detection compared to all low respiratory airway isolates along the study period was 0.02%. All samples were purulent and more than 10(7) P. multocida colony-forming units/millilitre were detected. All strains were penicillin-sensitive. CONCLUSIONS: Pasteurella multocida respiratory infection is rare, although it is probably underestimated owing to the fact that it is difficult to identify when coexisting with oropharingeal flora. Characteristically, in affects old males with bronchial disease are involved and can be life threatening in severely immunosuppressed patients.

Aged↗
PubMed1999

Changes of the fluidity of mitochondrial membranes induced by the permeability transition.

The dynamic properties of protein and lipid regions of mitochondrial membranes during the permeability transition (PT) process were studied by following the anisotropy changes of hematoporphyrin (HP) and 1,6-diphenyl-1,3,5-hexatriene (DPH), respectively. We show that opening of the PT pore is accompanied by a remarkable increase of mitochondrial membrane fluidity which is specifically localized to protein sites, while lipid domains are unaffected. The increased membrane fluidity is not related to the collapse of transmembrane potential that follows the PT, as demonstrated by a comparison between the anisotropy properties of permeabilized mitochondria and impermeable, depolarized organelles. Parameters such as osmotic swelling and temperature, which are shown to affect the mitochondrial membrane dynamics in the absence of permeability transition, cannot alone account for the pore dynamical properties. We suggest that the observed increase in fluidity is mainly due to a conformational change of pore-forming protein(s) during the "assembly" of the PT pore.

Animals↗
PubMed1999

Photodynamic action of porphyrin on Ca2+ influx in endoplasmic reticulum: a comparison with mitochondria.

We have studied the distribution properties of haematoporphyrin (HP) and protoporphyrin (PP) in mitochondria and endoplasmic reticulum after isolation from rat liver. The photosensitizing efficiency of porphyrin on the Ca2+ influx function of microsomes has been compared with that obtained on Ca2+ uptake in mitochondria. HP and PP are accumulated in microsomes to a greater extent than in mitochondria, both porphyrins binding to membrane protein sites. The Ca2+ influx functions of mitochondria and microsomes, before and after irradiation in the presence of HP or PP, were studied by following the changes in the free Ca2+ concentration in the medium as revealed by the variations in fluorescence intensity of the Ca2+ indicator Calcium Green-1. For the same amount of incorporated porphyrin, the Ca2+ influx function of microsomes is degraded by irradiation more rapidly than that of mitochondria. The protective effect of dithiothreitol suggests that thiol groups in the Ca2+-transporting enzyme are the preferential targets of the photodynamic effect. These results suggest that intracellular Ca2+ movements are altered primarily by the endoplasmic reticulum rather than by mitochondrial damage, in good agreement with other observations made in porphyrin-loaded irradiated cells.

Animals↗
PubMed1999

beta-catenin expression pattern in stage I and II ovarian carcinomas : relationship with beta-catenin gene mutations, clinicopathological features, and clinical outcome.

The immunohistochemical expression pattern of beta-catenin has been correlated with beta-catenin gene mutations, clinicopathological features, and disease outcome in 69 stage I and II ovarian carcinomas. beta-Catenin expression was localized in the nuclei, in addition to the cytoplasm and membrane, in 11 tumors (16%): nine endometrioid carcinomas with widespread nuclear expression and two serous carcinomas with focal nuclear expression. The remaining 58 carcinomas (84%) only had membranous beta-catenin expression. All but one of the endometrioid carcinomas with nuclear beta-catenin expression had considerable squamous metaplasia, and five of these cases had large areas of endometrioid tumor of low malignant potential. In addition, beta-catenin nuclear expression was observed in atypical epithelial cells in endometriotic glands adjacent to an endometrioid carcinoma. Sequencing was performed on 25 tumors and corresponding normal tissue: all 13 endometrioid tumors as well as 12 carcinomas of other histological types (four serous, two clear cell, two mucinous, and two mixed). There were oncogenic mutations in the phosphorylation sequence for GSK-3beta in exon 3 of the beta-catenin gene in seven endometrioid carcinomas with beta-catenin nuclear expression. Three mutations affected codon 32 (D32G, D32Y, and D32Y), one affected codon 33 (S33C), two affected codon 37 (S37C and S37F), and one affected codon 41 (T41A). No mutations were observed in the other 18 carcinomas analyzed, comprising two endometrioid and two serous carcinomas with beta-catenin nuclear expression, and 14 carcinomas of different histological types with only membranous expression. In the univariate and multivariate survival analyses, beta-catenin nuclear expression was selected as an indicator of good prognosis, because no patient whose tumor expressed beta-catenin in the nuclei showed relapses or died, in contrast to the 19 relapses and deaths among patients with tumors that only had beta-catenin membranous expression, including three of the four patients with endometrioid carcinomas. Oncogenic beta-catenin mutation is characteristic of a group of endometrioid carcinomas with a good prognosis, most of which originate from previous benign or borderline lesions. Endometrioid carcinomas with exclusively membranous expression of beta-catenin seem to represent a different subgroup of carcinomas that probably have a worse prognosis. In early-stage ovarian cancer, determination of the beta-catenin expression pattern could prove to be a useful marker for selecting low-risk patients.

Adult↗
PubMed1999

Dominant dystrophic epidermolysis bullosa (Pasini) caused by a novel glycine substitution mutation in the type VII collagen gene (COL7A1).

A 12 y old girl with the albopapuloid variant (Pasini) of dominant dystrophic epidermolysis bullosa is studied. The albopapuloid lesions developed within the first year of life, contained milia and were associated with pruritus. Mutation detection of the COL7A1 gene revealed a G-->A transition at nucleotide position 6110 in the mutant allele converting a glycine to glutamic acid (G2037E). This report adds to the expanding database on COL7A1 mutations in dystrophic epidermolysis bullosa.

Amino Acid Substitution↗
PubMed1999

[Eikenella corrodens: five year experience in a general hospital].

BACKGROUND: Eikenella corrodens is a Gram negative bacillus that colonizes oropharyngeal and digestive mucous membranes. It is difficult to isolate in the laboratory. This might be the reason why its implication in different types of infection is not well known. We report a five year experience in a general hospital. METHODS: Charts of 125 infections have been retrospectively reviewed. No selective medium was employed for the isolation. RESULTS: Infections were related to oral cavity in 68 patients (54%) and to gastrointestinal tract in 45 (36%); in 12 no clear source could be found. The prevailing infections were: postsurgical 32, apendiceal 22, abscesses 22, and traumatic wounds 12. Seventy two percent of the patients were adults and 93% were hospitalized. Eighteen patients had a neoplasia, 6 were diabetic, and 3 had some kind of immunodeficiency. Etiology was polymicrobial in 91% of the cases, the prevailing association being with Streptococcus spp. (74%). Only 15 patients had a pure culture, 11 of which had received previous antibiotic treatment. The most serious infections were a subdural empyema secondary to sinusitis, a mediastinitis following a mouth floor abscess, and a peritonitis with pleural empyema preceded by an hepatic abscess. The three were polymicrobial. Outcome was always satisfactory with no associated death. CONCLUSIONS: The origin of these infections is almost always clearly related with its habitat, but their spectrum is wide. Polymicrobial condition of most of them makes diagnosis as well as interpretation of its clinical meaning difficult. Nevertheless, association of E. corrodens with serious or slow healing infections fully justifies the efforts towards its isolation and the choice of antibiotics to which it is susceptible.

Adult↗
PubMed1998

Effects of photodynamic action on respiration in nonphosphorylating mitochondria.

We have studied the effects of singlet oxygen produced by photodynamic action on respiration in nonphosphorylating mitochondria (state 4). Isolated rat liver mitochondria were incubated with 3 microM hematoporphyrin and irradiated at 365 nm with a fluence rate of 25 W/m2. After short durations of irradiation, state 4 respiration with beta-hydroxybutyrate as substrate increases while respiration with succinate is negligibly affected. When mitochondria have been uncoupled with carbonylcyanide-p-trifluoromethoxyphenyl hydrazone before irradiation, no change occurs in beta-hydroxybutyrate-driven respiration, while succinate-driven respiration strongly decreases. Stimulation of state 4 NADH respiration cannot be explained by slippage of the NADH ubiquinone oxidoreductase because the stoichiometry of the redox pump was found insensitive to photodynamic action. In the light of the metabolite theory for linear enzymatic chains applied to state 4 respiration (Brand et al., Biochem. J. 255, 535-539, 1988), these results suggest that stimulation of NADH respiration is simply due to an increase of membrane leaks which occurs after irradiation. In the case of succinate-driven respiration, a strong inhibition of succinate dehydrogenase activity has been demonstrated after irradiation. It can be suggested that this inhibition introduces a negative control coefficient over state 4 respiration, counterbalancing the effects due to leakage.

Animals↗
PubMed1998

Photophysical properties of porphyrin planar aggregates in liposomes.

This paper describes studies of some photophysical properties of non-covalent planar aggregates of hematoporphyrin and protoporphyrin. This porphyrin species has been recently discovered and can be generated in lipid bilayers such as liposomes and inner mitochondrial membranes. The relative weight of this species in different media, as compared to porphyrin monomers and stacked aggregates, has been deduced by fluorescence decay studies. In contrast with what is observed for stacked aggregates, promotion of planar suprastructures can occur both in aqueous and lipid environments. The spectroscopic properties are very similar to those of the corresponding monomers, in particular as regards the shape of the absorption and emission spectra. The fluorescence decay times are generally higher than those of the monomers, and depend on the medium in which the planar aggregates are formed. The photooxidation properties of porphyrin planar aggregates, as revealed by oxygen consumption and histidine photodegradation upon irradiation at 365 nm, were compared to those of the monomers. The extent of the photooxidation process is nearly 20-30% higher in planar aggregates than in the monomers. In contrast, it is well known that cofacial aggregates are photochemically inert and only monomeric species of porphyrin are efficient photosensitizers. The biological relevance of these findings is discussed.

1,2-Dipalmitoylphosphatidylcholine↗
PubMed1998

Electroneutral Na-coupled cotransporter expression in the kidney during variations of NaCl and water metabolism.

The purpose of the present study was to analyze the long-term regulation of renal bumetanide-sensitive Na+-K+-2Cl- cotransporter and thiazide-sensitive Na+-Cl- cotransporter gene expression during changes in NaCl and water metabolism. Male Wistar rats exposed to high or low NaCl intake, saline loading, dehydration, water loading, and furosemide administration during 7 days were studied. Control groups had access to regular food and tap water. Rats were kept in metabolic cages for 4 days before and during the experiment to determine daily urinary electrolyte excretion and osmolarity. At the end of the experiment, creatinine clearance and serum electrolyte levels were also measured. Kidneys were excised and macroscopically subdivided into cortex and outer and inner medulla. Total RNA was extracted from each individual cortex or outer medulla by use of the guanidine/cesium chloride method. The Na+-K+-2Cl- cotransporter expression in outer medulla total RNA was assessed by nonradioactive Northern blot analysis and the Na+-Cl- cotransporter expression in renal cortex total RNA was assessed by semiquantitative polymerase chain reaction. Experimental maneuvers were adequately tolerated, and all groups developed the appropriate renal response to each challenge. However, the level of expression of both cotransporters did not change in any model, except for a 2.8-fold increase in the Na+-Cl- cotransporter expression during dehydration. We conclude that nephron adaptation to 7-day modifications in NaCl and water metabolism does not include changes in the amount of electroneutral sodium-coupled cotransporter gene expression at the mRNA level.

Animals↗
PubMed1997

Singlet oxygen produced by photodynamic action causes inactivation of the mitochondrial permeability transition pore.

We have studied the effects of singlet oxygen produced by photodynamic action on the cyclosporin A-sensitive permeability transition (PT) in isolated rat liver mitochondria. Mitochondria were incubated with 3 microM hematoporphyrin and irradiated at 365 nm with a fluence rate of 25 watts/m2. For short durations of irradiation (60 s) the adenine nucleotide translocase was inactivated, but mitochondria retained their ability to form a proton electrochemical gradient and accumulated Ca2+ and Pi at the same rate as non-irradiated controls. Strikingly, however, the oxidative effects of photodynamic action prevented opening of the PT pore which is normally induced by Ca2+ plus Pi or by treatment with diethyl pyrocarbonate (a histidine reagent) or diamide (a thiol oxidant). We show that the most likely targets for photodynamic action are critical histidines that undergo degradation. Irradiated, hematoporphyrin-loaded mitochondria treated with diethyl pyrocarbonate or diamide still undergo the PT when treated with phenylarsine oxide, which reacts with a critical dithiol involved in pore modulation (Petronilli, V., Costantini, P., Scorrano, L., Colonna, R., Passamonti, S., and Bernardi, P. (1994) J. Biol. Chem. 269, 16638-16642). These data suggest (i) that the dithiol cysteines are not oxidized by photodynamic action, but rather became inaccessible to oxidants; and (ii) that irradiation of hematoporphyrin-loaded mitochondria does not lead to pore denaturation, but rather to site-selective inactivation of discrete pore functional domains.

Animals↗
PubMed1997

Induction of mitochondrial dysfunction and apoptosis in HeLa cells by bis-pyridinium oximes, a newly synthesized family of lipophilic biscations.

When tested on HeLa cells, bis-pyridinium oximes (BPO), a family of newly synthesized molecules whose charged pyridinium moieties are linked by a linear polymethylene chain of variable length (N = 3 to 12) have been shown to possess an inhibitory effect on cell growth and finally to provoke cell death. BPO-affected cells displayed reduced mitochondrial oxygen consumption and ATP stores and were blocked in the G1 phase of the cell cycle. Mitochondrial membrane potential, as assayed with the dye 3,3'-diexyloxacarbocyanine iodide [DiOC6(3)], increased in BPO-treated cells with time of exposure. Cell growth inhibition as well mitochondrial dysfunction were observed only with derivatives having a long polymethylene linking chain (N > or = 6). Furthermore, the concentration of the compound eliciting such effects was inversely related to the number of methylene groups in the linking chain. None of the BPO with N = 6 to 12 modified the mitochondrial DNA content, relative to the nuclear DNA content. In BPO (N = 8 and N = 12)-treated cells, chromatin fragmentation and internucleosomal DNA cleavage occurred massively, indicating that the death mode induced by these compounds is apoptosis. The possible pathway of action and the potential pharmacological interest of these compounds are discussed.

Adenosine Triphosphate↗
PubMed1997

Effects of Photofrin photodynamic action on mitochondrial respiration and superoxide radical generation.

Cyanide-resistant respiration increases after irradiation of isolated mitochondria in the presence of Photofrin. This suggests an enhancement of electron leakage which has been evaluated by measuring superoxide radical formation in submitochondrial particles incubated with 6 micrograms/ml Photofrin in the medium and irradiated with increasing doses of light at 365 nm. After a dose of 4.5 kJ/m2 has been delivered, superoxide generation increases by a factor of approximately 2.5 at the level of NADH dehydrogenase and by a factor approximately 1.5 in the cyt bc1 region. These effects have been compared with changes observed in NADH-, succinate- and ascorbate-driven respiration and their implications discussed.

Animals↗
PubMed1996

Photosensitizing potencies of the structural analogues of benzoporphyrin derivative in different biological test systems.

Benzoporphyrin derivative (BPD) is a potent photosensitizer in biological systems. There are four structural analogues of BPD. The analogues share the same chromophor, which results in their having almost identical optical spectra, extinction coefficients, and yields of singlet oxygen. Small structural differences affect their photosensitizing potency in various biological systems, and thus make them an interesting tool to study the structure-activity relationship. The ranking of the photosensitizing potency of the analogues differed depending on the test system. The more efficient photosensitization of tumor cell lines by the highly lipophilic monoacids as compared to that by less lipophilic diacids correlated positively with the partition coefficient, and was related to the rate of diffusion into the cells. However, in the assay systems where PDT targets were located in the membrane (red blood cells hemolysis, enveloped vesicular stomatitis virus, isolated mitochondria) there was very little difference in photosensitizing potency of BPD analogues. The results indicate that the evaluation of photosensitizers is affected by the test system and thus for photosensitizers screening purposes, the choice of the test system should be made based on the intended ultimate use.

Animals↗