Análisis de los datos de monitorización del ventilador para la toma de decisiones en ventilación mecánica invasiva crónica / Analysis of ventilator monitoring data for decision-making in chronic invasive mechanical ventilation

El uso de la ventilación mecánica invasiva crónica se ha incrementado progresivamente en pediatría. Su uso tiene importantes beneficios, pero también riesgos asociados. La terapia ventilatoria debe ser supervisada en forma constante y dentro de los métodos de evaluación clínica de la ventilación se encuentra el análisis de los datos de monitorización almacenados en la memoria interna del ventilador. Estos datos contienen información almacenada durante el uso del ventilador que puede ayudarnos a tomar decisiones. Es importante considerar que la precisión de la información depende de la tecnología del ventilador y los componentes utilizados. El objetivo de esta revisión es dar a conocer la utilidad y limitaciones de la información de monitorización del ventilador mecánico en pacientes usuarios de ventilación mecánica crónica por traqueostomía, junto con describir su interpretación estructurada en forma sencilla y con ejemplos clínicos.

Long-term mechanical ventilation has increased in pediatric patients. Its use has important benefits, but also associated risks. Ventilatory therapy must be constantly monitored, and ventilator data analysis it's one of the evaluation methods. The device data contains information stored during the ventilator use and can help us with therapy decisions. The information accuracy depends on ventilator technology and the components that are used for ventilation. The objective of this review is to present the usefulness and limitations of the information on mechanical ventilator monitoring devices in patients using chronic mechanical ventilation by tracheostomy describing and structured interpretation in a simple way with the use of clinical examples.

Fístula colovaginal secundaria a enfermedad diverticular complicada / Colovaginal fistula secondary to complicated diverticular disease

La fístula colovaginal es de ocurrencia excepcional en la práctica clínica, sin embargo, cuando se presenta, la enfermedad diverticular es una de las etiologías más frecuentes. Se presentan tres casos de fístula colovaginal que complican un enfermedad diverticular tratados por autores. Todas las pacientes tenían antecedentes de una histerectomía por vía abdominal, y la primera manifestación clínica de la fístula fue la pérdida de gases y deposiciones por la vagina. Solo en una de ellas existía el antecedente de una diverculitis. Los estudios preoperatorios incluyeron un enema baritado, que demostró la fístula en todos los casos, una colonoscopia en solo una, que fue incompleta por estenosis del sigmoides distal a la fístula y tomografía computada de abdomen en otro paciente que demostró una diverticulitis aguda. Las tres pacientes fueron sometidas a una sigmoidectomía con anastomosis mecánica a nivel del promontorio con buena evolución postoperatoria. Se plantea que la existencia de una fístula colovaginal, sobre todo si existe el antecedente de una histerectomía debe hacer plantear entre otras alternativas, la etiología diverticular. La sigmoidectomía es el tratamiento de elección evitando reparaciones por vía vaginal, que no tratan el origen de la fístula.

Complementation analysis with new genetic markers in Phaffia rhodozyma.

Isolation and characterization of auxotrophic mutants from wild-type and astaxanthin mutant strains of Phaffia rhodozyma is described. Differences in survival were observed when u.v. irradiation of P. rhodozyma wild-type and astaxanthin mutant strains were incubated in the dark or exposed to photoreactivating light. Ultra-violet mutagenesis was not effective to produce auxotrophic mutants in this yeast. Auxotrophic mutants were obtained with high efficiency through a nystatin enrichment procedure after a N-methyl-N'-nitro-N-nitrosoguanidine (NGT) mutagenic treatment with a 0.12% survivor level. Stringent mutagenetic conditions were needed to obtain P. rhodozyma auxotrophs. The most frequent mutants were ade- and met- in a rather narrow auxotroph spectrum. These results may be associated with a possible diploid condition of this yeast. The high number of adenine auxotrophs obtained in relation to other auxotrophic mutants suggests the possibility of some degree of heterozygosity in the wild-type strain UCD 67-385.

Genetic transformation of astaxanthin mutants of Phaffia rhodozyma.

Stable red astaxanthin-producing transformants were obtained after genetic transformation of two Phaffia rhodozyma mutants. A yellow mutant, accumulating beta-carotene, and an albino mutant, accumulating phytoene, from P. rhodozyma were transformed using a genomic library of wild-type strain UCD 67-385 in the pBluescript vector. Hybridization assays, using the pBluescript DNA as a radioactive probe, indicate integration of vector sequences into the genome of the transformants. Transformants DNA was digested with restriction endonucleases, ligated with T4 DNA ligase and then used to transform E. coli. Ampicillin resistant plasmids, containing 0.1, 0.2, and 2.5 kb DNA inserts of P. rhodozyma, were rescued from the yeast red transformants. The molecular analysis indicate that transformation has occurred by an integration event of donor DNA into the genome of the host strains.

Genetics and electrophoretic karyotyping of wild-type and astaxanthin mutant strains of Phaffia rhodozyma.

In this work we establish the chromosomal composition of a wild-type, one astaxanthin and two beta-carotene overproducer strains of the red yeast Phaffia rhodozyma. The method used has been pulsed field gel electrophoresis, which has determined 9 DNA chromosomal bands in the yeast genome. The two largest bands are triplets and two other bands, VI and VIII, seem to be doublets. The size of the chromosomal bands varies between 0.35 and 2.5 Mb, suggesting a genome size of 25 Mb. The technique used, complemented with hybridization assays using specific DNA probes, provides direct information about the genomic organization of P. rhodozyma. We have also cloned and located in chromosomal bands different DNA sequences that code for the translation elongation factor 1 alpha (ef-1 alpha), a 7.6 kb BamHI fragment of repetitive DNA (possibly rDNA) and a randomly chosen fragment (named locus R2). Additionally, we have detected a chromosomal length polymorphism between wild-type strains and mutant strains affecting carotenogenesis obtained in our laboratory.

Molecular cloning and expression in Saccharomyces cerevisiae and Neurospora crassa of the invertase gene from Neurospora crassa.

A plasmid (named pCN2) carrying a 7.6 kb BamHI DNA insert was isolated from a Neurospora crassa genomic library raised in the yeast vector YRp7. Saccharomyces cerevisiae suco and N. crassa inv strains transformed with pNC2 were able to grow on sucrose-based media and expressed invertase activity. Saccharomyces cerevisiae suco (pNC2) expressed a product which immunoreacted with antibody raised against purified invertase from wild type N. crassa, although S. cerevisiae suc+ did not. The cloned DNA hybridized with a 7.6 kb DNA fragment from BamHI-restricted wild type N. crassa DNA. Plasmid pNC2 transformed N. crassa Inv- to Inv+ by integration either near to the endogenous inv locus (40% events) or at other genomic sites (60% events). It appears therefore that the cloned DNA piece encodes the N. crassa invertase enzyme. A 3.8 kb XhoI DNA fragment, derived from pNC2, inserted in YRp7, in both orientation, was able to express invertase activity in yeast, suggesting that it contains an intact invertase gene which is not expressed from a vector promoter.

Genetic control of a structural polymer of the Neurospora crassa cell wall.

The heteropolysaccharide present in fraction 1 of the Neurospora crassa cell wall has been characterized in wild-type and morphological mutant strains of this fungus. Single and double mutations have been studied to determine possible genetic interactions controlling the chemical composition of such heteropolysaccharides . Single mutations studied were peak-2, scumbo ( FGSC 49), ragged ( FGSC 296), and crisp -1 ( FGSC 488). Double mutations studied were peak-2, scumbo ( FGSC 419), and ragged crisp -1. In all these strains, the main constituents of the heteropolysaccharide were glucose, mannose and galactose. Glycosidic linkages binding these neutral sugars have been identified by gas-liquid chromatography. A chemical structure of fraction I heteropolysaccharide is proposed. The results obtained with double mutants suggest the existence of genetic interactions, such as complementation or additive effects of lesions of different genes, to control the chemical composition and structure of the cell wall and the morphology of N. crassa mycelium.

Genetic and biochemical characterization of D-arabinose dehydrogenase from Neurospora crassa.

D-Arabinose dehydrogenase has been purified to homogeneity from wild-type Neurospora crassa 74-A (FGSC 262) and from two colonial mutants, col-15a (FGSC 1391) and col-16a (FGSC 1349), found to contain more of the enzyme. The enzymes were characterized by measurement of several kinetic and physicochemical parameters. The enzymes were the same in all characteristics studied thus far. Immunological studied performed with enzyme preparations from the three strains showed antigenic identity and indicated that those colonial strains contain more normal enzyme, rather than the usual amount of an altered "improved" enzyme. Quantitation of the enzyme in crude extracts, performed by single radial immunodiffusion, showed that the colonial strains have twice the level of enzyme as the wild-type strain. Genetic characterization, performed by analysis of meiotic products, heterokaryosis, and reversions, indicated that the difference in D-arabinose dehydrogenase activity detected among the three strains is probably determined by one gene. The genetic control, structural or regulatory of this enzyme activity is different from that determining the morphological alterations exhibited by mutant strains carrying the col-15 or col-16 gene.

Characterization of the carbohydrate component of fraction I in the Neurospora crassa cell wall.

The carbohydrate portion of fraction I of the Neurospora crassa cell wall has been analyzed for sugar composition by gas-liquid chromatography and colorimetric methods. The analysis was performed comparatively in a wild-type strain (RL 3-8A) and three morphological mutants: scumbo (FGSC 49), peak-2a (a mutant known to be allelic to biscuit), and ragged (FGSC 296). Fraction I of all strains studied contains glucose, mannose, and galactose as the main sugars. Uronic acids and amino sugars are also present in small amounts. The glycosidic linkages binding the neutral sugars were analyzed by Lindberg's combined gas chromatography-mass spectrometry techniques for identification of the partially methylated alditol acitate sugar derivatives. The main polymeric portion of fraction I seems to be a linear glucan with the glucose residues linked by 1 leads to 3 and 1 leads to 4 bonds. A mannan portion with a branched configuration is also present, with galactose as the sugar residue which serves as branches in the molecule(s). The branched mannan portion appears to increase in amount in correlation with more drastic morphological changes of the mycelia. In this respect, the mutant ragged has the lowest mycelial growth rate and the largest amount of mannan. The importance of the polysaccharide structure of fraction I on the colonial morphology of the mycelia is discussed.