Partial cricotracheal resection for pediatric subglottic stenosis: a single institution's experience in 60 cases.

In our study, 60 infants and children, each with a severe subglottic stenosis (SGS), underwent partial cricotracheal resection (PCTR) with primary thyrotracheal anastomosis. According to the Myer-Cotton classification, two were grade II, 41 were grade III and 17 were grade IV stenoses. Of the 60 patients, 57 (95%) are presently decannulated, and one patient sustained a complete restenosis. Two patients with better than 80% subglottic airways still are waiting for decannulation: one because of bilateral cricoarytenoid joint fixation and the second because of temporary stenting of the subglottis with a Montgomery T-tube. The rate of decannulation is 97% (36 of 37 cases) in primary PCTRs, 100% (13 of 13 cases) in salvage PCTRs for failed laryngotracheal reconstructions (LTR) and 70% (7 of 10 cases) in extended PCTRs (i.e., PCTR associated with an additional open-airway procedure).

Changes in sleeping and basal energy expenditure and substrate oxidation induced by short term thyroxin administration in man.

The present study was designed to explore the thermogenic effect of thyroid hormone administration and the resulting changes in nitrogen homeostasis. Normal male volunteers (n = 7) received thyroxin during 6 weeks. The first 3-week period served to suppress endogenous thyroid secretion (180 micrograms T4/day). This dose was doubled for the next 3 weeks. Sleeping energy expenditure (respiratory chamber) and BMR (hood) were measured by indirect calorimetry, under standardized conditions. Sleeping heart rate was continuously recorded and urine was collected during this 12-hour period to assess nitrogen excretion. The changes in energy expenditure, heart rate and nitrogen balance were then related to the excess thyroxin administered. After 3 weeks of treatment, serum TSH level fell to 0.15 mU/L, indicating an almost complete inhibition of the pituitary-thyroid axis. During this phase of treatment there was an increase in sleeping EE and sleeping heart rate, which increased further by doubling the T4 dose (delta EE: +8.5 +/- 2.3%, delta heart rate +16.1 +/- 2.2%). The T4 dose, which is currently used as a substitutive dose, lead to a borderline hyperthyroid state, with an increase in EE and heart rate. Exogenous T4 administration provoked a significant increase in urinary nitrogen excretion averaging 40%. It is concluded that T4 provokes an important stimulation of EE, which is mostly mediated by an excess protein oxidation.

Effect of a 1-hour single bout of moderate-intensity exercise on fat oxidation kinetics.

The present study aimed to examine the effects of a prior 1-hour continuous exercise bout (CONT) at an intensity (Fat(max)) that elicits the maximal fat oxidation (MFO) on the fat oxidation kinetics during a subsequent submaximal incremental test (IncrC). Twenty moderately trained subjects (9 men and 11 women) performed a graded test on a treadmill (Incr), with 3-minute stages and 1-km.h(-1) increments. Fat oxidation was measured using indirect calorimetry and plotted as a function of exercise intensity. A mathematical model (SIN) including 3 independent variables (dilatation, symmetry, and translation) was used to characterize the shape of fat oxidation kinetics and to determine Fat(max) and MFO. On a second visit, the subjects performed CONT at Fat(max) followed by IncrC. After CONT performed at 57% +/- 3% (means +/- SE) maximal oxygen uptake (Vo(2max)), the respiratory exchange ratio during IncrC was lower at every stage compared with Incr (P < .05). Fat(max) (56.4% +/- 2.3% vs 51.5% +/- 2.4% Vo(2max), P = .013), MFO (0.50 +/- 0.03 vs 0.40 +/- 0.03 g.min(-1), P < .001), and fat oxidation rates from 35% to 70% Vo(2max) (P < .05) were significantly greater during IncrC compared with Incr. However, dilatation and translation were not significantly different (P > .05), whereas symmetry tended to be greater in IncrC (P = .096). This study showed that the prior 1-hour continuous moderate-intensity exercise bout increased Fat(max), MFO, and fat oxidation rates over a wide range of intensities during the postexercise incremental test. Moreover, the shape of the postexercise fat oxidation kinetics tended to have a rightward asymmetry.

Partial trisomy 20q in a newborn with dextrocardia.

A female newborn is reported with dextrocardia and a partial trisomy 20q, derived from a t(2;20) paternal translocation. The most discriminating findings of the condition include brachycephaly, bulging forehead, deep set eyes, short nose, large ears, dimpled chin, short neck and a heart defect. Previously reported patients with this rare chromosomal anomaly are reviewed.

Pancreatic islet adaptation to fasting is dependent on peroxisome proliferator-activated receptor alpha transcriptional up-regulation of fatty acid oxidation.

The cellular response to fasting and starvation in tissues such as heart, skeletal muscle, and liver requires peroxisome proliferator-activated receptor-alpha (PPARalpha)-dependent up-regulation of energy metabolism toward fatty acid oxidation (FAO). PPARalpha null (PPARalphaKO) mice develop hyperinsulinemic hypoglycemia in the fasting state, and we previously showed that PPARalpha expression is increased in islets at low glucose. On this basis, we hypothesized that enhanced PPARalpha expression and FAO, via depletion of lipid-signaling molecule(s) for insulin exocytosis, are also involved in the normal adaptive response of the islet to fasting. Fasted PPARalphaKO mice compared with wild-type mice had supranormal ip glucose tolerance due to increased plasma insulin levels. Isolated islets from the PPARalpha null mice had a 44% reduction in FAO, normal glucose use and oxidation, and enhanced glucose-induced insulin secretion. In normal rats, fasting for 24 h increased islet PPARalpha, carnitine palmitoyltransferase 1, and uncoupling protein-2 mRNA expression by 60%, 62%, and 82%, respectively. The data are consistent with the view that PPARalpha, via transcriptionally up-regulating islet FAO, can reduce insulin secretion, and that this mechanism is involved in the normal physiological response of the pancreatic islet to fasting such that hypoglycemia is avoided.

Molecular identification and characterization of the Arabidopsis delta(3,5),delta(2,4)-dienoyl-coenzyme A isomerase, a peroxisomal enzyme participating in the beta-oxidation cycle of unsaturated fatty acids.

Degradation of unsaturated fatty acids through the peroxisomal beta-oxidation pathway requires the participation of auxiliary enzymes in addition to the enzymes of the core beta-oxidation cycle. The auxiliary enzyme delta(3,5),delta(2,4)-dienoyl-coenzyme A (CoA) isomerase has been well studied in yeast (Saccharomyces cerevisiae) and mammals, but no plant homolog had been identified and characterized at the biochemical or molecular level. A candidate gene (At5g43280) was identified in Arabidopsis (Arabidopsis thaliana) encoding a protein showing homology to the rat (Rattus norvegicus) delta(3,5),delta(2,4)-dienoyl-CoA isomerase, and possessing an enoyl-CoA hydratase/isomerase fingerprint as well as aspartic and glutamic residues shown to be important for catalytic activity of the mammalian enzyme. The protein, named AtDCI1, contains a peroxisome targeting sequence at the C terminus, and fusion of a fluorescent protein to AtDCI1 directed the chimeric protein to the peroxisome in onion (Allium cepa) cells. AtDCI1 expressed in Escherichia coli was shown to have delta(3,5),delta(2,4)-dienoyl-CoA isomerase activity in vitro. Furthermore, using the synthesis of polyhydroxyalkanoate in yeast peroxisomes as an analytical tool to study the beta-oxidation cycle, expression of AtDCI1 was shown to complement the yeast mutant deficient in the delta(3,5),delta(2,4)-dienoyl-CoA isomerase, thus showing that AtDCI1 is also appropriately targeted to the peroxisome in yeast and has delta(3,5),delta(2,4)-dienoyl-CoA isomerase activity in vivo. The AtDCI1 gene is expressed constitutively in several tissues, but expression is particularly induced during seed germination. Proteins showing high homology with AtDCI1 are found in gymnosperms as well as angiosperms belonging to the Monocotyledon or Dicotyledon classes.

Identification and functional characterization of auxiliary enzymes of the β-oxidation in " Arabidopsis thaliana "

Abstract: The ß-oxidation is the universal pathway that allows living organisms to degrade fatty acids. leading to lipid homeostasis and carbon and energy recovery from the fatty acid molecules. This pathway is centred on four core enzymatic activities sufficient to degrade saturated fatty acids. Additional auxiliary enzymes of the ß-oxidation are necessary for the complete degradation of a larger array of molecules encompassing the unsaturated fatty acids. The main pathways of the ßoxidation of fatty acids have been investigated extensively and auxiliary enzymes are well-known in mammals and yeast. The comparison of the established ß-oxidation systems suggests that the activities that are required to proceed to the full degradation of unsaturated fatty acids are present regardless of the organism and rely on common active site templates. The precise identity of the plant enzymes was unknown. By homology searches in the genome of Arabidopsis thaliana, I identified genes. encoding for proteins that could be orthologous to the yeast or animal auxiliary enzymes Δ 3, Δ 2-enoyl-CoA isomerase, Δ 3,5, Δ 2,4 -dienoyl-CoA isomerase, and type 2 enoyl-CoA hydratase. I established that these genes are expressed in Arabidopsis and that their expression can be correlated to the expression of core ß-oxidation genes. Through the observation of chimeric fluorescent protein fusions, I demonstrated that the identified proteins are localized in the peroxisóme, the only organelle where the ß-oxidation occurs in plants. Enzymatic assays were performed with the partially purified enzymes to demonstrate that the identified enzymes can catalyze the same in vitro reactions as their non-plant orthologs. The activities in vivo of the plant enzymes were demonstrated by heterologous complementation of the corresponding yeast Saccharomyces cerevisiae mutants. The complementation was visualized using the artificial polyhydroxyalkanoate (PHA) production in yeast peroxisomes. The recombinant strains, expressing a Pseudomonas aeruginosa PHA synthase modified for a peroxisomal localization, produce this polymer that serves as a trap for the 3-hydroxyacyl-CoA intermediaries of the ßoxidation and that reflects qualitatively and quantitatively the array of molecules that are processed through the ß-oxidation. This complementation demonstrated the implication of the plant Δ 3, Δ 2-enoyl-CoA isomerases and Δ3,5, Δ2,4-dienoyl-CoA isomerase in the degradation of odd chain position unsaturated fatty acids. The presence of a monofunctional type 2 enoyl-CoA hydratase is a novel in eukaryotes. Downregulation of the corresponding gene expression in an Arabidopsis line, modified to produce PHA in the peroxisome, demonstrated thàt this enzyme participates in vivo to the conversion of the intermediate 3R-hydroxyacyl-CoA, generated by the metabolism of fatty acids with a cis (Z)-unsaturated bond on an even-numbered carbon, to the 2Eenoyl-CoA for further degradation through the core ß-oxidation cycle. Résumé: La ß-oxydation est une voie universelle de dégradation des acides gras qui permet aux organismes vivants d'assurer une homéostasie lipidique et de récupérer l'énergie et le carbone contenus dans les acides gras. Le coeur de cette voie est composé de quatre réactions enzymatiques suffisantes à la dégradation des acides gras saturés. La présence des enzymes auxiliaires de la ß-oxydation est nécessaire à la dégradation d'une gamme plus étendue de molécules comprenant les acides gras insaturés. Les voies principales de la ß-oxydation des acides gras ont été étudiées en détail et les enzymes auxiliaires sont déterminées chez les mammifères et la levure. La comparaison entre les systèmes de ß-oxydation connus suggère que les activités requises pour la dégradation complète des acides gras insaturés reposent sur la présence de site actifs similaires. L'identité précise des enzymes auxiliaires chez les plantes était inconnue. En cherchant par homologie dans le génome de la plante modèle Arabidopsis thaliana, j'ai identifié des gènes codant pour des protéines pouvant être orthologues aux enzymes auxiliaires Δ3 Δ2-enoyl-CoA isomérase, Δ 3,5 Δ 2,4-dienoyl-CoA isomérase et enoyl-CoA hydratase de type 2 d'origine fongique ou mammalienne. J'ai établi la corrélation de l'expression de ces gènes dans Arabidopsis avec celle de gènes des enzymes du coeur de la ß-oxydation. En observant des chimères de fusion avec des protéines fluorescentes, j'ai démontré que les protéines identifiées sont localisées dans le péroxysomes, le seul organelle où la ß-oxydation se déroule chez les plantes. Des essais enzymatiques ont été conduits avec ces enzymes partiellement purifiées pour démontrer que les enzymes identifiées sont capables de catalyser in vitro les mêmes réactions que leurs orthologues non végétaux. Les activités des enzymes végétales in vivo ont été .démontrées par complémentation hétérologue des mutants de délétion correspondants de levure Saccharomyces cerevisiae. La visualisation de la complémentation est rendue possible par la synthèse de polyhydroxyalcanoate (PHA) dans les péroxysomes de levure. Les souches recombinantes expriment la PHA synthase de Pseudomonas aeruginosa modifiée pour être localisée dans le péroxysome produisent ce polymère qui sert de piège pour les 3-hydroxyacylCoAs intermédiaires de la ß-oxydation et qui reflète qualitativement et quantitativement la gamme de molécules qui subit la ß-oxydation. Cette complémentation a permis de démontrer que les Δ3, Δ2-enoyl-CoA isomérases, et la Δ3.5, Δ2,4-dienoyl-CoA isomérase végétales sont impliquées dans la dégradation des acides gras insaturés en position impaire. L'enoyl-CoA hydratase de type 2 monofonctionelle est une enzyme nouvelle chez les eucaryotes. La sous-expression du gène correspondant dans une lignée d'Arabidopsis modifiée pour produite du PHA dans le péroxysome a permis de démontrer que cette enzyme participe in vivo à la dégradation des acides gras ayant une double liaison en conformation cis (Z) en position paire.

Reproducibility of Fatmax and Fat Oxidation Rates during Exercise in Recreationally Trained Males.

Aerobic exercise training performed at the intensity eliciting maximal fat oxidation (Fatmax) has been shown to improve the metabolic profile of obese patients. However, limited information is available on the reproducibility of Fatmax and related physiological measures. The aim of this study was to assess the intra-individual variability of: a) Fatmax measurements determined using three different data analysis approaches and b) fat and carbohydrate oxidation rates at rest and at each stage of an individualized graded test. Fifteen healthy males [body mass index 23.1±0.6 kg/m2, maximal oxygen consumption ([Formula: see text]) 52.0±2.0 ml/kg/min] completed a maximal test and two identical submaximal incremental tests on ergocycle (30-min rest followed by 5-min stages with increments of 7.5% of the maximal power output). Fat and carbohydrate oxidation rates were determined using indirect calorimetry. Fatmax was determined with three approaches: the sine model (SIN), measured values (MV) and 3rd polynomial curve (P3). Intra-individual coefficients of variation (CVs) and limits of agreement were calculated. CV for Fatmax determined with SIN was 16.4% and tended to be lower than with P3 and MV (18.6% and 20.8%, respectively). Limits of agreement for Fatmax were -2±27% of [Formula: see text] with SIN, -4±32 with P3 and -4±28 with MV. CVs of oxygen uptake, carbon dioxide production and respiratory exchange rate were <10% at rest and <5% during exercise. Conversely, CVs of fat oxidation rates (20% at rest and 24-49% during exercise) and carbohydrate oxidation rates (33.5% at rest, 8.5-12.9% during exercise) were higher. The intra-individual variability of Fatmax and fat oxidation rates was high (CV>15%), regardless of the data analysis approach employed. Further research on the determinants of the variability of Fatmax and fat oxidation rates is required.

Analysis of the contribution of the β-oxidation auxiliary enzymes in the degradation of the dietary conjugated linoleic acid 9-cis-11-trans-octadecadienoic acid in the peroxisomes of Saccharomyces cerevisiae

Beta-oxidation of the conjugated linoleic acid 9-cis,11-trans-octadecadienoic acid (rumenic acid) was analyzed in vivo in Saccharomyces cerevisiae by monitoring polyhydroxyalkanoate production in the peroxisome. Polyhydroxyalkanoate is synthesized by the polymerization of the beta-oxidation intermediates 3-hydroxyacyl-CoAs via a bacterial polyhydroxyalkanoate synthase targeted to the peroxisome. The amount of polyhydroxyalkanaote synthesized from the degradation of rumenic acid was found to be similar to the amount synthesized from the degradation of 10-trans,12-cis-octadecadienoic acid, oleic acid or 10-cis-heptadecenoic acid. Furthermore, the degradation of 10-cis-heptadecenoic acid was found to be unaffected by the presence of rumenic acid in the media. Efficient degradation of rumenic acid was found to be independent of the Delta(3,5),Delta(2,4)-dienoyl-CoA isomerase but instead relied on the presence of Delta(3),Delta(2)-enoyl-CoA isomerase activity. The presence of the unsaturated monomer 3-hydroxydodecenoic acid in polyhydroxyalkanoate derived from rumenic acid degradation was found to be dependent on the presence of a Delta(3),Delta(2)-enoyl-CoA isomerase activity. Together, these data indicate that rumenic acid is mainly degraded in vivo in S. cerevisiae through a pathway requiring only the participation of the auxiliary enzymes Delta(3),Delta(2)-enoyl-CoA isomerase, along with the enzyme of the core beta-oxidation cycle.

Partial cricotracheal resection in children weighing less than 10 kilograms.

OBJECTIVES: To assess the long-term outcome, safety, and efficacy of partial cricotracheal resection (PCTR) for subglottic stenosis in a group of children and infants weighing less than 10 kg at the time of the surgery. STUDY DESIGN: Historical cohort study. SETTING: Academic tertiary medical center. SUBJECTS AND METHODS: Thirty-six children weighing less than 10 kg at the time of the surgery were compared to a group of 65 children who weighed more than 10 kg. The Kaplan Meier method and Cox regression were carried out to detect differences in decannulation time and rates and to examine the influence of various parameters (i.e., comorbidities, type of surgery, and complications requiring revision surgery) at the time of decannulation. Evaluation of the long-term outcome was based on questionnaires assessing breathing, voice, and swallowing. RESULTS: Decannulation rate was 92 percent (33/36) for the group of children weighing less than 10 kg. No significant differences were found between the two body weight groups with respect to the aforementioned covariates. The median follow-up period was nine years (range, 1-23 yrs). Questionnaire responses revealed completely normal breathing and swallowing in 72 percent and 90 percent of the children, respectively. Seventy-one percent of the patients considered their voice to be rough or weak. CONCLUSION: PCTR in infants and children weighing less than 10 kg is a safe and efficient technique with similar long-term results when compared to results seen in older and heavier children.

Oxidation of proteins: Basic principles and perspectives for blood proteomics.

Protein oxidation mechanisms result in a wide array of modifications, from backbone cleavage or protein crosslinking to more subtle modifications such as side chain oxidations. Protein oxidation occurs as part of normal regulatory processes, as a defence mechanism against oxidative stress, or as a deleterious processes when antioxidant defences are overcome. Because blood is continually exposed to reactive oxygen and nitrogen species, blood proteomics should inherently adopt redox proteomic strategies. In this review, we recall the biochemical basis of protein oxidation, review the proteomic methodologies applied to analyse redox modifications, and highlight some physiological and in vitro responses to oxidative stress of various blood components.

Reflections on Partial Least Squares Path Modeling

The purpose of the present article is to take stock of a recent exchange in Organizational Research Methods between critics (Rönkkö & Evermann, 2013) and proponents (Henseler et al., 2014) of partial least squares path modeling (PLS-PM). The two target articles were centered around six principal issues, namely whether PLS-PM: (1) can be truly characterized as a technique for structural equation modeling (SEM); (2) is able to correct for measurement error; (3) can be used to validate measurement models; (4) accommodates small sample sizes; (5) is able to provide null hypothesis tests for path coefficients; and (6) can be employed in an exploratory, model-building fashion. We summarize and elaborate further on the key arguments underlying the exchange, drawing from the broader methodological and statistical literature in order to offer additional thoughts concerning the utility of PLS-PM and ways in which the technique might be improved. We conclude with recommendations as to whether and how PLS-PM serves as a viable contender to SEM approaches for estimating and evaluating theoretical models.

Partial Cricotracheal Resection in Children: Potential Pitfalls and Avoidance of Complications.

OBJECTIVES: To delineate the various factors contributing to failure or delay in decannulation after partial cricotracheal resection (PCTR) in children. STUDY DESIGN: Case series. SETTING: Academic tertiary medical center. SUBJECTS AND METHODS: A retrospective case review of 100 children who underwent PCTR between 1978 and 2008 for severe subglottic stenosis using an ongoing database. RESULTS: Ninety of 100 (90%) patients were decannulated. Six patients needed secondary tracheostomy. The results of the preoperative evaluation showed grade II stenosis in four patients, grade III in 64 patients, and grade IV in 32 patients. The overall decannulation rate was 100 percent in grade II, 95 percent in grade III, and 78 percent in grade IV stenosis. Fourteen (14%) patients required revision open surgery. The most common cause of revision surgery was posterior glottic stenosis. Partial anastomotic dehiscence was seen in four patients. Delayed decannulation (>1 year) occurred in nine patients. Overall mortality rate in the whole series was 6 percent. No deaths were directly related to the surgery. No iatrogenic recurrent laryngeal nerve injury was present in the entire series. CONCLUSION: Comorbidities and associated syndromes should be addressed before PCTR is planned to improve the final postoperative outcome in terms of decannulation. Perioperative morbidity due to anastomotic dehiscence, to a certain extent, can be avoided by intraoperative judgment in the selection of double-stage surgery when more than five tracheal rings need to be resected. Subglottic stenosis with glottic involvement continues to pose a difficult challenge to pediatric otolaryngologists, often necessitating revision procedures.