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Biomedical subjects

B García

Publications and source records attributed to B García.

At least 37 records · Page 2Linked to original sources
PubMed2001

Differences in tissue fatty acid composition between reared and wild sharpsnout sea bream, Diplodus puntazzo (Cetti, 1777).

The fatty acid composition and lipid content of white muscle, liver and mesenteric fat, in reared v. wild sharpsnout sea bream (Diplodus puntazzo) were compared. The mesenteric fat index fat weight/body weight) and the lipid contents of both white muscle and liver proved consistently higher in farmed v. wild sharpsnout sea bream (79.0 (SE 13.1) v. 38.7 (SE 5.1) g/kg, 188.4 (SE 30.0) v. 58.2 (SE 3.9) g/kg and 27.2 (SE 3.7) v. 17.3 (SE 1.9) g/kg, respectively). The higher values of linoleic, eicosapentaenoic, docosahexaenoic and n-3 series acids in reared fish muscle make reared sharpsnout more favourable for human consumption. In reared fish mesenteric fat, polyunsaturated fatty acids reached higher levels (32.54 (SE 0.71) g/100 g total fatty acids than those found in wild fish (26.08 (SE 1.38) g/100 g total fatty acids or even present in the diet (28.34 g/100 g total fatty acids). Compared with cultured fish, wild sharpsnout displayed a higher content of n-3 fatty acids in liver fat (31.67 (SE 1.13) g/100 g total fatty acids), but lower in mesenteric fat (20.35 (SE 1.41) g/100 g total fatty acids). Atherogenic index values were similar for wild and reared fish in all tissues, while the index of thrombogenicity of muscle and mesenteric fat (0.353 (SE 0.012) and 0.402 (SE 0.021) respectively) was significantly increased in wild fish probably due to the omnivorous habits of the species and/or to seasonal food variations. Depending on the time of the year or the season, reared fish could be more suitable for human consumption than wild fish.

Animals↗
PubMed2000

Stereoselective synthesis of 7,11-guaien-8,12-olides from santonin. Synthesis of podoandin and (+)-zedolactone A.

Photochemical rearrangement of hydroxy ester 2, easily obtained from santonin (1), afforded butenolide 4, a good starting material for the synthesis of 7,11-guaien-8,12-olides. Compound 4 has been transformed into compound 10, which has been used for the synthesis of podoandin (5) and (+)-zedolactone A (ent-6). Regioselective elimination of the acetyl group on C10 afforded directly podoandin (5). For the synthesis of ent-6, a hydroxyl group has been regio- and stereoselectively introduced at the 4alpha-position through the 3alpha,4alpha-epoxide 15. The basic hydrolysis of the 10-acetyl group in compound 18 took place with concomitant intramolecular conjugated addition of the alkoxide to the butenolide moiety to give ether 19. Cleavage of the 7,10-oxido bridge via the lactone enolate afforded (+)-zedolactone A (ent-6). This synthesis has allowed for the establishment of the absolute stereochemistry of natural zedolactone A as the enantiomer of our synthetic product.

4-Butyrolactone↗
PubMed2000

Theoretical and experimental study of the acetohydroxamic acid protonation: the solvent effect.

The mechanism of the protonation of acetohydroxamic acid is investigated comparing experimental results and ab initio calculations. Experimentally, the UV spectral curves were recorded at different temperatures, at constant dioxane/water concentration, and at very high concentrations of strong mineral acids. The process is followed by monitoring the changes in the UV curves with increasing acid concentration. The molecular structures and the solvation energies were calculated with the RHF, B3LYP, and MP2 methods. The solvent is treated as a continuum of uniform dielectric constant. The isolated molecule of acetohydroxamic acid exhibits two protonation sites, the carbonyl oxygen and the nitrogen atom. In dioxane/water mixture, the RHF calculations predict the existence of a third cation of low stability, where the proton is bonded to the OH oxygen. With the MP2 ab initio calculations, the free energies of the formation processes in solution of the two most stable cations, CH3COH-NHOH+ (O3H+) and CH3CO-NH2OH+ have been evaluated to be -160.2 kcalmol(-1) and -157.6 kcal mol(-1). The carbonyl site is the most active center in solution and in the gas phase. The carbonyl site is also the most active center in the UV measurements. Experimentally, the ionization constant was found to be pK(O3H+) = -2.21 at 298.15 K, after the elimination of the medium effects using the Cox-Yates equation for hight acidity levels. Experiments and ab initio calculations indicate that K(O3H+) decreases with the temperature.

Cations↗
PubMed2000

From a short amino acidic sequence to the complete gene.

A useful strategy directed to the isolation of a required gene with a high GC content is reported. Using a degenerate oligonucleotide probe, deduced from the amino terminus of a protein, it is possible to obtain a fragment of DNA containing its encoding gene by PCR amplification. Furthermore, the cloning of a desired gene can be accomplished in two steps by using an oligonucleotide deduced (i) from an internal sequence, (ii) from a consensus sequence, or (iii) from a DNA sequence adjacent to a disrupting element (transposon, insertion sequence, cassette). This method, which could be applied to a bacteriophage, plasmid, or cosmid genomic library, has been successfully used for cloning several genes from different biological systems.

Amino Acid Sequence↗
PubMed2000

Carbon source regulation of a dextranase gene from the filamentous fungus Penicillium minioluteum.

The regulation of dextranase (dexA) gene expression in the filamentous fungus Penicillium minioluteum grown on different carbon sources was studied. Growth in the presence of dextran leads to high expression of the dextranase enzyme, but growth in starch, glucose, glycerol, lactose and sorbitol did not. Dextran induced dexA gene expression at the mRNA level. However, in cultures containing dextran plus glucose or glycerol, the transcript was detected 24 h later than in the case where dextran was the only carbon source. When the glucose or glycerol concentration in the dextran-containing medium was kept at about 1% (w/v), no dextranase-transcripts were detected. It was found that both glucose and glycerol inhibited enzyme synthesis, because 1% (w/v) addition of both carbon sources to dextran-growing cultures was able to abolish the inducing effect of dextran. Our results suggest that dextran utilization responds to both specific induction and to glucose and glycerol repression, providing evidence that P. minioluteum dexA expression is regulated by the carbon source at the transcriptional level.

Blotting, Northern↗
PubMed2000

Schizosaccharomyces pombe ehs1p is involved in maintaining cell wall integrity and in calcium uptake.

The Schizosaccharomyces pombe mutant ehs1-1 mutant was isolated on the basis of its hypersensitivity to Echinocandin and Calcofluor White, which inhibit cell wall synthesis. The mutant shows a thermosensitive growth phenotype that is suppressed in the presence of an osmotic stabiliser. The mutant also showed other cell wall-associated phenotypes, such as enhanced sensitivity to enzymatic cell wall degradation and an imbalance in polysaccharide synthesis. The ehs1 + gene encodes a predicted integral membrane protein that is 30% identical to Saccharomyces cerevisiae Mid1p, a protein that has been proposed to form part of a calcium channel. As expected for such a function, we found that ehs1+ is involved in intracellular Ca2+ accumulation. High external Ca2+ concentrations suppressed all phenotypes associated with the ehs1 null mutation, suggesting that the cell integrity defects of ehs1 mutants result from inadequate levels of calcium in the cell. We observed a genetic relationship between ehs1+ and the protein kinase C homologue pck2+. pck2+ suppressed all phenotypes of ehs1-1 mutant cells. Overproduction of pck2p is deleterious to wild-type cells, increasing 1,3-beta-D-glucan synthase activity and promoting accumulation of extremely high levels of Ca2+. The lethality associated with pck2p, the increase in 1,3-beta-D-glucan synthase production and the strong Ca2+ accumulation are all dependent on the presence of ehs1p. Our results suggest that in fission yeast ehs1p forms part of a calcium channel that is involved in the cell wall integrity pathway that includes the kinase pck2p.

Amino Acid Sequence↗
PubMed2000

Phenylacetyl-coenzyme A is the true inducer of the phenylacetic acid catabolism pathway in Pseudomonas putida U.

Aerobic degradation of phenylacetic acid in Pseudomonas putida U is carried out by a central catabolism pathway (phenylacetyl-coenzyme A [CoA] catabolon core). Induction of this route was analyzed by using different mutants specifically designed for this objective. Our results revealed that the true inducer molecule is phenylacetyl-CoA and not other structurally or catabolically related aromatic compounds.

Acetyl Coenzyme A↗
PubMed2000

New method for the selection of multicopy transformants of Pichia pastoris, using 3-amino-1,2,4 triazol.

The methylotrophic yeast Pichia pastoris has been successfully used for the expression of many heterologous proteins. The level of expression of some of these proteins depends on the copy number of the gene inserted into the yeast genome. Several methods have been reported in the past few years for the isolation of multicopy transformants. One of these methods used an expression vector that contains the bacterial kanamycin-resistance gene Tn903kanr, which confers resistance to G418. Here, we report a different selection method in a mutant strain of P. pastoris (his3-) based on the resistance to 3-amino-1,2,4 triazol, with a vector containing the HIS3 gene from Saccharomyces cerevisiae. Using this selection method, we isolated here P. pastoris transformants containing several copies of the dextranase gene (dex) from Penicillium minioluteum.

Amitrole↗
PubMed2000

[The recommendations of GESIDA/SEFH/PNS for improving adherence to antiretroviral treatment. AIDS Study Group of the Spanish Society of Hospital Pharmacy and the National Plan on AIDS of the Minister of Health and Consumers].

The main objective of HAART is to achieve a complete suppression of the viral replication for long time. However, when the therapeutic drug levels are low, HIV can replicate and it can develop resistances. This fact can be the reason of treatment failure, HIV transmission of resistant strains and therefore an inappropriate use of the economical resources. In order to get the adequate therapeutic drug levels it is necessary to have a good adherence to the treatment. We review the factors that influence the adherence, the evaluation methods and we recommend the possible intervention strategies which should be given by a multidisciplinary team, integrated by physicians, pharmacists, nurses, psychologists and other personal support. To start HAART is not an emergency. For this reason is very important to prepare to the patient and to identify the non-adherence factors in order to correct it. Once the HAART is indicated it is very important to offer information during the medical prescription and when the drugs are dispensed. During the therapy is necessary to follow actively all patients on HAART. In order to make therapeutical decisions we need to know the patient drug adherence rate. We recommend to use several methods to calculate the drug adherence rate, being the most commonly used the patient interview, the patient questionnaire, the refill count, the pharmacy visits rate together with the viral load evolution of the patient. In order to get all this information it is necessary to have a very good communication between all the people involved in HIV infected patients care. If non-adherence is detected it is necessary to start the intervention strategies to correct it and if they fail it might be necessary in some cases to stop HAART. The potential benefits of the adherence programs can justify the economical spend in human and hospital facilities resources.

Anti-HIV Agents↗
PubMed2000

Intestinal bleeding and occlusion associated with Shiga toxin-producing Escherichia coli O127:H21.

We report a case of a nine-year old boy with vomiting, abdominal pain and fever, who underwent surgery with a diagnosis of appendicitis in Mendoza and from whom a Shiga toxin-producing Escherichia coli (STEC) O127:H21 strain was recovered. Forty-eight hours after surgery he presented bilious vomiting and two episodes of intestinal bleeding. Laboratory findings included: hematocrit, 35%; blood urea nitrogen, 0.22 g/L. The urinary output was normal. The following day physical examination showed an alert mildly hydrated child, without fever but with distended and painful abdomen. The patient was again submitted to surgery with a diagnosis of intestinal occlusion. Bleeding and multiple adhesions in jejunum and ileum were found. The patient still had tense and painful abdomen and presented two bowel movements with blood; hematocrit fell to 29% and blood urea nitrogen rose to 0.32 g/L. STEC O127:H21 eae(-)/Stx2/Stx2vh-b(+)/E-Hly(+) was isolated from a stool sample. He was discharged after 10 days of hospitalization and no long-term complications such as HUS or TTP were observed. This is the first report, to our knowledge, on the isolation of E. coli O127:H21, carrying the virulence factors that characterize STEC strains, associated to an enterohemorrhagic colitis case. This serotype was previously characterized as a non-classic enteropathogenic E. coli (EPEC). STEC infections can mimic infectious or noninfectious pathologies. Therefore an important aspect of clinical management is making the diagnosis using different criteria thereby avoiding misdiagnoses which have occasionally led to invasive diagnostic and therapeutic procedures or the inappropriate use of antibiotics.

Abdomen↗
PubMed2000

[Retinitis pigmentosa, pattern dystrophy and fundus flavimaculatus not related to mutations in rhodopsine, peripherin/RDS and ROM-1 genes].

PURPOSE: Several families have been described in which a variety of retinal dystrophies were apparently caused by a mutation in the peripherin/RDS gene. We present clinical and genetic findings in a new family affected with a retinal dystrophy with features of retinosis pigmentosa, pattern dystrophy and fundus flavimaculatus in which a mutation in the peripherin/RDS gene has been ruled out. METHODS: A screening in the rhodopsin, peripherin/RDS and ROM1 genes was done in the affected members of the family by PCR amplification and SSCP (single strand conformation polymorphism) analysis. RESULTS: No mutation was found in any of the family members. CONCLUSIONS: Mutations in other genes may be involved in retinal dystrophies.

Adult↗
PubMed1999

Novel biodegradable aromatic plastics from a bacterial source. Genetic and biochemical studies on a route of the phenylacetyl-coa catabolon.

Novel biodegradable bacterial plastics, made up of units of 3-hydroxy-n-phenylalkanoic acids, are accumulated intracellularly by Pseudomonas putida U due to the existence in this bacterium of (i) an acyl-CoA synthetase (encoded by the fadD gene) that activates the aryl-precursors; (ii) a beta-oxidation pathway that affords 3-OH-aryl-CoAs, and (iii) a polymerization-depolymerization system (encoded in the pha locus) integrated by two polymerases (PhaC1 and PhaC2) and a depolymerase (PhaZ). The complete assimilation of these compounds requires two additional routes that specifically catabolize the phenylacetyl-CoA or the benzoyl-CoA generated from these polyesters through beta-oxidation. Genetic studies have allowed the cloning, sequencing, and disruption of the genes included in the pha locus (phaC1, phaC2, and phaZ) as well as those related to the biosynthesis of precursors (fadD) or to the catabolism of their derivatives (acuA, fadA, and paa genes). Additional experiments showed that the blockade of either fadD or phaC1 hindered the synthesis and accumulation of plastic polymers. Disruption of phaC2 reduced the quantity of stored polymers by two-thirds. The blockade of phaZ hampered the mobilization of the polymer and decreased its production. Mutations in the paa genes, encoding the phenylacetic acid catabolic enzymes, did not affect the synthesis or catabolism of polymers containing either 3-hydroxyaliphatic acids or 3-hydroxy-n-phenylalkanoic acids with an odd number of carbon atoms as monomers, whereas the production of polyesters containing units of 3-hydroxy-n-phenylalkanoic acids with an even number of carbon atoms was greatly reduced in these bacteria. Yield-improving studies revealed that mutants defective in the glyoxylic acid cycle (isocitrate lyase(-)) or in the beta-oxidation pathway (fadA), stored a higher amount of plastic polymers (1.4- and 2-fold, respectively), suggesting that genetic manipulation of these pathways could be useful for isolating overproducer strains. The analysis of the organization and function of the pha locus and its relationship with the core of the phenylacetyl-CoA catabolon is reported and discussed.

Acetyl Coenzyme A↗
PubMed1999

[Acute respiratory insufficiency as initial manifestation of brain stem lesions].

We describe three patients with different brainstem lesions (bulbar angioma, bulbar infarct, and Arnold-Chiari malformation) who debuted with acute respiratory insufficiency. Other neurological manifestations had gone unobserved in all three cases. Respiratory insufficiency worsened notably during sleep to the point that mechanical ventilation was required or death occurred (Ondine s curse). The patient with a bulbar angioma is stable with only assisted ventilation by a nasal route at night, with good quality of life. Our conclusions are that: a) central nervous system anomalies need to be investigated as possible causes of respiratory insufficiency when lungs are normal; b) the respiratory control of patients with brainstem lesions should be studied, particularly at night (polysomnography), and c) even when awake-state ventilation is adequate, nighttime assisted ventilation may be required.

Acute Disease↗
PubMed1999

Acute eosinophilic pneumonia associated with antidepressant agents.

Acute eosinophilic pneumonia is a severe syndrome characterized by fever, lung infiltrates, blood eosinophilia and respiratory failure. We describe a case of acute eosinophilic pneumonia associated with clomipramine and sertraline. A 40-year-old woman was admitted to the emergency department with 37.9 degrees C and respiratory rate of 35 respirations per minute. Blood analysis showed PaO2 = 57.6 mm Hg and HCO3- = 21.7 mmol/l and 12.2% eosinophils. Chest X-ray showed infiltrates in both lower lobes. She was taking clomipramine 25 mg bid for the last 4 weeks and sertraline 50 mg/day for the last week. Other causes of acute eosinophilic pneumonia such as parasitic and fungal infections or collagen diseases were discarded. Both antidepressant were stopped and the patient became afebrile and asymptomatic. A week later the patient was discharged from hospital. Physicians should be aware of this adverse antidepresant reaction which may result in severe pulmonary symptoms.

Acute Disease↗
PubMed1999

[Forestier's disease. Ear, nose and throat manifestations].

Forestier's disease is a skeletal pathology that sometimes affects the head and neck as a consequence of hyperostotic involvement of the cervical spine. We report the case of a 73-year-old man who had progressive difficulty in swallowing solids. Gastrointestinal endoscopy revealed a bony mass in the hypopharynx. The case is described and the disease manifestations in head and neck are discussed.

Aged↗
PubMed1998

Catabolism of phenylacetic acid in Escherichia coli. Characterization of a new aerobic hybrid pathway.

The paa cluster of Escherichia coli W involved in the aerobic catabolism of phenylacetic acid (PA) has been cloned and sequenced. It was shown to map at min 31.0 of the chromosome at the right end of the mao region responsible for the transformation of 2-phenylethylamine into PA. The 14 paa genes are organized in three transcription units: paaZ and paaABCDEFGHIJK, encoding catabolic genes; and paaXY, containing the paaX regulatory gene. The paaK gene codes for a phenylacetyl-CoA ligase that catalyzes the activation of PA to phenylacetyl-CoA (PA-CoA). The paaABCDE gene products, which may constitute a multicomponent oxygenase, are involved in PA-CoA hydroxylation. The PaaZ protein appears to catalyze the third enzymatic step, with the paaFGHIJ gene products, which show significant similarity to fatty acid beta-oxidation enzymes, likely involved in further mineralization to Krebs cycle intermediates. Three promoters, Pz, Pa, and Px, driven the expression of genes paaZ, paaABCDEFGHIJK, and paaX, respectively, have been identified. The Pa promoter is negatively controlled by the paaX gene product. As PA-CoA is the true inducer, PaaX becomes the first regulator of an aromatic catabolic pathway that responds to a CoA derivative. The aerobic catabolism of PA in E. coli represents a novel hybrid pathway that could be a widespread way of PA catabolism in bacteria.

Acetyl Coenzyme A↗
PubMed1998

Molecular characterization of the phenylacetic acid catabolic pathway in Pseudomonas putida U: the phenylacetyl-CoA catabolon.

Fourteen different genes included in a DNA fragment of 18 kb are involved in the aerobic degradation of phenylacetic acid by Pseudomonas putida U. This catabolic pathway appears to be organized in three contiguous operons that contain the following functional units: (i) a transport system, (ii) a phenylacetic acid activating enzyme, (iii) a ring-hydroxylation complex, (iv) a ring-opening protein, (v) a beta-oxidation-like system, and (vi) two regulatory genes. This pathway constitutes the common part (core) of a complex functional unit (catabolon) integrated by several routes that catalyze the transformation of structurally related molecules into a common intermediate (phenylacetyl-CoA).

Acetyl Coenzyme A↗