Unexpected difficult airway caused by subglottic cyst. Clinical case / Vía aérea difícil no anticipada por quiste subglótico: caso clínico

Acquired subglottic cysts are an unusual cause of stridor. They are usually developed following a tracheal intubation episode in a premature patient. We report the clinical case of an ex-premature patient who was diagnosed as having an acquired subglottic cyst after causing a difficult intubation situation. This situation can potentially uncover the obstruction and initiate the complete diagnostic and therapeutic process.

Una causa poco frecuente de estridor laríngeo corresponde a quistes subglóticos. En general se desarrollan luego de una intubación en un paciente prematuro. Se presenta el caso clínico de un ex prematuro que presenta una intubación difícil dada por la presencia de un quiste subglótico. Gracias a esta situación, se inició el estudio y tratamiento del quiste.

High Prevalence of Diastolic Dysfunction in Incident Patients on Peritoneal Dialysis: Association with Low Thyroid Hormones.

BACKGROUND/AIMS: Diastolic dysfunction (DD) and low levels of thyroid hormones (TH) are frequent found in chronic kidney disease; both are associated with all-cause and cardiovascular mortality. However, a link between them has not yet been established. The aim of this study was to analyze DD as a surrogate marker of fibrosis and its association with TH in incident patients on peritoneal dialysis (PD). METHODS: A cross-sectional study with 183 incident patients on PD with preserved ejection fraction was performed. Clinical and demographic data were registered. Serum total and free (t/f) triiodothyronine (T3), thyroxin (T4), and thyroid stimulating hormone levels were determined by RIA kits, albumin and high-sensitivity C-reactive protein by conventional assays. Transthoracic 2D echocardiogram was performed for evaluation of left ventricular (LV) mass and ejection fraction. DD was evaluated using pulsed-wave tissue Doppler imaging. RESULTS: Patients were 43 ± 12, 42% with diabetes mellitus (DM). Some degree of DD was found in 62% of patients; 18% had grade I DD, 8% grade II DD and 36% grade III DD. Patients with grade III DD were more likely to have diabetes, older, high LV mass and low serum albumin, t/fT3 and tT4 levels. In logistic multivariate regression analysis, it was found that diabetes (B = -0.86, 95% CI 0.182-0.992, p < 0.05), hypertension (B = -0.95, 95% CI 0.184-0.817, p = 0.01) and tT3 (B = -1.94, 95% CI 0.023-0.876, p < 0.05) were associated with grade III DD. CONCLUSIONS: High prevalence of grade III DD was found in incident patients on PD. In addition to DM and hypertension, tT3 was found to be an independent risk factor for grade III DD and more studies are needed to understand the reasons as to why this association is present.

Mola hidatiforme parcial / Partial hydatidiform mole

Introducción: el término enfermedad trofoblástica gestacional es una anormal proliferación del trofoblasto, que desde el punto de vista histológico se clasifica en mola hidatiforme, mola invasora, coriocarcinoma y tumor del sitio de implantación del trofoblasto. Objetivo: describir las características clínicas y ultrasonográficas de una mola hidatiforme parcial o mola embrionada. Paciente: se presenta un caso de 24 sem de gestación con el diagnóstico ultrasonográfico de mola hidatidiforme parcial. Resultados: se realizó cariotipo fetal y determinación de niveles de gonadotropina coriónica en suero materno. Se hallaron defectos congénitos en el feto, por lo que se ofreció asesoramiento genético a la pareja, que optó por la interrupción de la gestación. Conclusiones: el diagnóstico prenatal fue confirmado por la anatomía patológica(AU)

Introduction: the term gestational trophoblastic disease is an abnormal proliferation of the trophoblast, which is histologically classified as hydatidiform mole, invasive mole, choriocarcinoma, and tumor trophoblast implantation site. Objective: to describe the clinical and ultrasonographic partial hydatidiform mole or mole embrionada. Patient: we report a 24- week - prenancy case with ultrasonographic diagnosis of partial hydatidiform mole. Results: fetal karyotype was performed and levels of chorionic gonadotropin in maternal serum were determined. We found congenital defects in the fetus, so genetic counseling was offered to the parents, who chose ending this pregnancy. Conclusions: the prenatal diagnosis was confirmed by pathology(AU)

Mola hidatiforme parcial / Partial hydatidiform mole

Introducción: el término enfermedad trofoblástica gestacional es una anormal proliferación del trofoblasto, que desde el punto de vista histológico se clasifica en mola hidatiforme, mola invasora, coriocarcinoma y tumor del sitio de implantación del trofoblasto. Objetivo: describir las características clínicas y ultrasonográficas de una mola hidatiforme parcial o mola embrionada. Paciente: se presenta un caso de 24 sem de gestación con el diagnóstico ultrasonográfico de mola hidatidiforme parcial. Resultados: se realizó cariotipo fetal y determinación de niveles de gonadotropina coriónica en suero materno. Se hallaron defectos congénitos en el feto, por lo que se ofreció asesoramiento genético a la pareja, que optó por la interrupción de la gestación. Conclusiones: el diagnóstico prenatal fue confirmado por la anatomía patológica

Introduction: the term gestational trophoblastic disease is an abnormal proliferation of the trophoblast, which is histologically classified as hydatidiform mole, invasive mole, choriocarcinoma, and tumor trophoblast implantation site. Objective: to describe the clinical and ultrasonographic partial hydatidiform mole or mole embrionada. Patient: we report a 24- week - prenancy case with ultrasonographic diagnosis of partial hydatidiform mole. Results: fetal karyotype was performed and levels of chorionic gonadotropin in maternal serum were determined. We found congenital defects in the fetus, so genetic counseling was offered to the parents, who chose ending this pregnancy. Conclusions: the prenatal diagnosis was confirmed by pathology

Saccharomyces cerevisiae phosphoenolpyruvate carboxykinase: the relevance of Glu299 and Leu460 for nucleotide binding.

A homology model of Saccharomyces cerevisiae phosphoenolpyruvate (PEP) carboxykinase (ATP + oxaloacetate right arrow over left arrow ADP + PEP + CO(2)) in complex with its substrates shows that the isobutyl group of Leu460 is in close proximity to the adenine ring of the nucleotide, while the carboxyl group of Glu299 is within hydrogen-bonding distance of the ribose 2'OH. The Leu460Ala mutation caused three-fold and seven-fold increases in the K (m) for ADPMn(-) and ATPMn(2-), respectively, while the Glu299Ala mutation had no effect. Binding studies showed losses of approximately 2 kcal mol(-1) in the nucleotide binding affinity due to the Leu460Ala mutation and no effect for the Glu299Ala mutation. PEP carboxykinase utilized 2'deoxyADP and 2'deoxyATP as substrates with kinetic and equilibrium dissociation constants very similar to those of ADP and ATP, respectively. These results show that the hydrophobic interaction between Leu460 and the adenine ring of the nucleotide significantly contributed to the nucleotide affinity of the enzyme. The 2'deoxy nucleotide studies and the lack of an effect of the Glu299Ala mutation in nucleotide binding suggest that the possible hydrogen bond contributed by Glu299 and the ribose 2'OH group may not be relevant for nucleotide binding.

Stereochemistry of the carboxylation reaction catalyzed by the ATP-dependent phosphoenolpyruvate carboxykinases from Saccharomyces cerevisiae and Anaerobiospirillum succiniciproducens.

The stereochemistry of CO(2) addition to phosphoenolpyruvate (PEP) to yield oxaloacetate catalyzed by ATP-dependent Saccharomyces cerevisiae and Anaerobiospirillum succiniciproducens PEP carboxykinases was determined using (Z)-3-fluorophosphoenolpyruvate ((Z)-F-PEP) as a substrate analog. A. succiniciproducens and S. cerevisiae PEP carboxykinases utilized (Z)-F-PEP with 1/14 and 1/47 the respective K(m) values for PEP. On the other hand, in the bacterial and yeast enzymes k(cat) was reduced to 1/67 and 1/48 the value with PEP, respectively. The binding affinity of pyridoxylphosphate-labeled S. cerevisiae and A. succiniciproducens PEP carboxykinases for PEP and (Z)-F-PEP was checked and found to be of similar magnitude for both substrates, suggesting that the lowered K(m) values for the fluorine-containing PEP analog are due to kinetic effects. The lowered k(cat) values when using (Z)-F-PEP as substrate suggest that the electron withdrawing effect of fluorine affects the nucleophilic attack of the double bond of (Z)-F-PEP to CO(2). For the stereochemical analyses, the carboxylation of (Z)-F-PEP was coupled to malate dehydrogenase to yield 3-fluoromalate, which was analyzed by (19)F NMR. The fluoromalate obtained was identified as (2R, 3R)-3-fluoromalate for both the A. succiniciproducens and S. cerevisiae PEP carboxykinases, thus indicating that CO(2) addition to (Z)-F-PEP, and hence PEP, takes place through the 2-si face of the double bond. These results, together with previously published data [Rose, I.A. et al. J. Biol. Chem. 244 (1969) 6130-6133; Hwang, S.H. and Nowak, T. Biochemistry 25 (1986) 5590-5595] indicate that PEP carboxykinases, no matter their nucleotide specificity, catalyze the carboxylation of PEP from the 2-si face of the double bond.

Saccharomyces cerevisiae phosphoenolpyruvate carboxykinase: relevance of arginine 70 for catalysis.

Saccharomyces cerevisiae phosphoenolpyruvate (PEP) carboxykinase is a key enzyme of the gluconeogenic pathway and catalyzes the decarboxylation of oxaloacetate and transfer of the gamma-phosphoryl group of ATP to yield PEP, ADP, and CO2 in the presence of a divalent metal ion. Previous experiments indicate that mutation of amino acid residues at metal site 1 decrease the enzyme catalytic efficiency and the affinity of the protein for PEP, evidencing the relevance of hydrogen-bond interactions between PEP and water molecules of the first coordination sphere of the metal ion for catalysis [Biochemistry 41 (2002) 12763]. To further understand the function of amino acid residues located in the PEP binding site, we have now addressed the catalytic importance of Arg70, whose guanidinium group is close to the PEP carboxyl group. Arg70 mutants of PEP carboxykinase were prepared, and almost unaltered kinetic parameters were found for the Arg70Lys PEP carboxykinase, while a decrease in 4-5 orders of magnitude for the catalytic efficiency was detected for the Arg70Gln and Arg70Met altered enzymes. To evaluate the enzyme interaction with PEP, the phosphopyridoxyl-derivatives of wild type, Arg70Lys, Arg70Gln, and Arg70Met S. cerevisiae PEP carboxykinase were prepared, and the change in the fluorescence emission of the probe upon PEP binding was used to obtain the dissociation equilibrium constant of the corresponding derivatized enzyme-PEP-Mn2+ complex. The titration experiments showed that a loss in 2.1 kcal/mol in PEP binding affinity is produced in the Arg70Met and Arg70Gln mutant enzymes. It is proposed that the electrostatic interaction between the guanidinium group of Arg70 and the carboxyl group of PEP is important for PEP binding and for further steps in catalysis.