Search

Introduction: Pharyngocutaneous fistula is the most significant complication after salvage total laryngectomy in patients who have received previous treatment with radiotherapy with or without chemotherapy. Objective: Our purpose is to review the fistula rate in radiated patients undergoing salvage total laryngectomy, to determine if the use of pectoralis major flap interposition reduces the incidence and duration of fistula and to examine other risk factors. Methods: We made a retrospective review of patients undergoing salvage total laryngectomy for exclusively larynx cancer after failure of primary curative radiotherapy between 2000 and 2017. General data from patients, risk factors and other complications were analyzed. Results: We identified 27 patients whose mean age was 66.4 years, mainly male (92.5%). The primary closure group without pectoralis major flap included 14 patients, and the group with pectoralis major flap closure included 13 patients. Pharyngocutaneous fistula was present in 15 patients (55.5%). Global pharyngocutaneous fistula rate was higher in the group of patients without pectoralis major flap comparing with those were the flap was interposed (78.6% versus 30.8%, p = 0.047). Also the pharyngocutaneous fistulas which need to be repaired with surgery (64.3% versus 7.7%, p = 0.03) and large pharyngostomes (64.3% versus 0%, p = 0.0004) were present in a higher rate in the group closed primary without pectoralis major flap. We did not find other risk factors with statistical significance. Oral diet initiation (84 days versus 21.5 days, p = 0.039) and the duration of hospitalization (98.3 days versus 27.2 days, p = 0.0041) were much lower in patients with a preventive pectoralis major flap. Two patients died as a consequence of complications of large pharyngostomes. Conclusions: Prophylactic pectoralis major flap reduced the incidence, severity and duration of fistula and should be considered during salvage total laryngectomy. Resumo: Introdução: A fístula faringocutânea é a complicação mais significativa após laringectomia total de resgate em pacientes que receberam tratamento prévio com radioterapia com ou sem quimioterapia. Objetivo: Revisar a taxa de fístula em pacientes irradiados submetidos a laringectomia total de resgate, para determinar se o uso de interposição de retalho do peitoral maior reduz a incidência e a duração da fístula e examinar outros fatores de risco. Método: Fizemos uma revisão retrospectiva de pacientes submetidos à laringectomia total de resgate para câncer exclusivamente laríngeo após falha da radioterapia curativa primária entre 2000 e 2017. Dados gerais dos pacientes, fatores de risco e outras complicações foram analisados. Resultados: Foram identificados 27 pacientes com média de 66,4 anos, principalmente do sexo masculino (92,5%). O grupo de fechamento primário sem retalho de peitoral maior incluiu 14 pacientes e o grupo de fechamento com retalho de peitoral maior incluiu 13 pacientes. Fístula faringocutânea esteve presente em 15 pacientes (55,5%). A taxa global de fístula faringocutânea foi maior no grupo de pacientes sem retalho de peitoral maior em comparação com aqueles que receberam o retalho (78,6% vs. 30,8%, p = 0,047). Além disso, as fístulas faringocutâneas que precisaram ser reparadas através de cirurgia (64,3% vs. 7,7%, p = 0,03) e grandes faringostomias (64,3% vs. 0%, p = 0,0004) apresentaram uma taxa mais alta no grupo fechado primariamente sem retalho do peitoral maior. Não encontramos outros fatores de risco com significância estatística. O início da dieta oral (84 dias vs. 21,5 dias, p = 0,039) e a duração da internação (98,3 dias vs. 27,2 dias, p = 0,0041) foram muito menores nos pacientes com uso preventivo do retalho do peitoral maior. Dois pacientes morreram em consequência de complicações de grandes faringostomias. Conclusões: O uso profilático do retalho do peitoral maior reduziu a incidência, a gravidade e a duração da fístula e deve ser considerado durante a laringectomia total de resgate. Keywords: Salvage total laryngectomy, Pectoralis major flap, Pharyngocutaneous fistula, Radiotherapy, Palavras-chave: Laringectomia total de resgate, Retalho do peitoral maior, Fístula faringocutânea, Radioterapia

We have developed a novel, rapid and easy calculation procedure for Mass Isotopomer Distribution Analysis based on multiple linear regression which allows the simultaneous calculation of the precursor pool enrichment and the fraction of newly synthesized labelled proteins (fractional synthesis) using linear algebra. To test this approach, we used the peptide RGGGLK as a model tryptic peptide containing three subunits of glycine. We selected glycine labelled in two 13 C atoms (13 C2 -glycine) as labelled amino acid to demonstrate that spectral overlap is not a problem in the proposed methodology. The developed methodology was tested first in vitro by changing the precursor pool enrichment from 10 to 40% of 13 C2 -glycine. Secondly, a simulated in vivo synthesis of proteins was designed by combining the natural abundance RGGGLK peptide and 10 or 20% 13 C2 -glycine at 1 : 1, 1 : 3 and 3 : 1 ratios. Precursor pool enrichments and fractional synthesis values were calculated with satisfactory precision and accuracy using a simple spreadsheet. This novel approach can provide a relatively rapid and easy means to measure protein turnover based on stable isotope tracers. Copyright © 2016 John Wiley & Sons, Ltd.

The pineal neuroindole melatonin exerts an exceptional variety of systemic functions. Some of them are exerted through its specific membrane receptors type 1 and type 2 (MT1 and MT2) while others are mediated by receptor-independent mechanisms. A potential transport of melatonin through facilitative glucose transporters (GLUT/SLC2A) was proposed in prostate cancer cells. The prostate cells have a particular metabolism that changes during tumor progression. During the first steps of carcinogenesis, oxidative phosphorylation is reactivated while the switch to the “Warburg effect” only occurs in advanced tumors and in the metastatic stage. Here, we investigated whether melatonin might change prostate cancer cell metabolism. To do so, 13C stable isotope-resolved metabolomics in androgen sensitive LNCaP and insensitive PC-3 prostate cancer cells were employed. In addition to metabolite 13C-labeling, ATP/AMP levels, and lactate dehydrogenase or pentose phosphate pathway activity were measured. Melatonin reduces lactate labeling in androgen-sensitive cells and it also lowers 13C-labeling of tricarboxylic acid cycle metabolites and ATP production. In addition, melatonin reduces lactate 13C-labeling in androgen insensitive prostate cancer cells. Results demonstrated that melatonin limits glycolysis as well as the tricarboxylic acid cycle and pentose phosphate pathway in prostate cancer cells, suggesting that the reduction of glucose uptake is a major target of the indole in this tumor type.

The accurate determination of creatinine in serum is essential for the diagnosis and treatment of kidney diseases. The determination of serum creatinine in clinical laboratories is routinely carried out by the Jaffe method or by enzymatic methods that may suffer from interferences. So, the development of reliable, fast and interference-free routine methods for complex serum samples is required. A fast method using isotope dilution mass spectrometry (IDMS) and gas chromatography mass spectrometry (GC–MS) was developed using minimally 13 C labeled creatinine analogs, multiple linear regression and rapid derivatization of creatinine with acetylacetone in 2 min by using focused microwave technology. The proposed method was validated with the analyses of two Certified Reference Materials (ERM-DA252a and ERM-DA253a) and compared with the Jaffe and enzymatic methods when analyzing real serum samples containing variable levels of bilirubin The proposed method is capable of providing accurate serum creatinine concentrations in less than 45 min from sample arrival to full data treatment and can be an alternative routine procedure for creatinine determinations in complex serum samples.

This work describes a methodology based on multiple linear regression and GC-MS for the determination of molar fractions of isotopically-labeled intracellular metabolites in cell cultures. Novel aspects of this work are: i) the calculation of theoretical isotopic distributions of the different isotopologues from an experimentally measured value of % 13C enrichment of the labeled precursor ii) the calculation of the contribution of lack of mass resolution of the mass spectrometer and different fragmentation mechanism such as the loss or gain of hydrogen atoms in the EI source to measure the purity of the selected cluster for each metabolite and iii) the validation of the methodology not only by the analysis of gravimetrically prepared mixtures of isotopologues but also by the comparison of the obtained molar fractions with experimental values obtained by GC-Combustion-IRMS based on 13C/12C isotope ratio measurements. The method is able to measure molar fractions for twenty-eight intracellular metabolites derived from glucose metabolism in cell cultures grown in the presence of 13C-labeled Glucose. The validation strategies demonstrate a satisfactory accuracy and precision of the proposed procedure. Also, our results show that the minimum value of 13C incorporation that can be accurately quantified is significantly influenced by the calculation of the spectral purity of the measured cluster and the number of 13C atoms of the labeled precursor. The proposed procedure was able to accurately quantify gravimetrically prepared mixtures of natural and labeled glucose molar fractions of 0.07% and mixtures of natural and labeled glycine at molar fractions down to 0.7%. The method was applied to initial studies of glucose metabolism of different prostate cancer cell lines.

We have developed a novel, rapid and easy calculation procedure for Mass Isotopomer Distribution Analysis based on multiple linear regression which allows the simultaneous calculation of the precursor pool enrichment and the fraction of newly synthesized labelled proteins (fractional synthesis) using linear algebra. To test this approach, we used the peptide RGGGLK as a model tryptic peptide containing three subunits of glycine. We selected glycine labelled in two

This work describes the first multiple spiking isotope dilution procedure for organic compounds using (13)C labeling. A double-spiking isotope dilution method capable of correcting and quantifying the creatine-creatinine interconversion occurring during the analytical determination of both compounds in human serum is presented. The determination of serum creatinine may be affected by the interconversion between creatine and creatinine during sample preparation or by inefficient chemical separation of those compounds by solid phase extraction (SPE). The methodology is based on the use differently labeled (13)C analogues ((13)C1-creatinine and (13)C2-creatine), the measurement of the isotopic distribution of creatine and creatinine by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and the application of multiple linear regression. Five different lyophilized serum-based controls and two certified human serum reference materials (ERM-DA252a and ERM-DA253a) were analyzed to evaluate the accuracy and precision of the proposed double-spike LC-MS/MS method. The methodology was applied to study the creatine-creatinine interconversion during LC-MS/MS and gas chromatography-mass spectrometry (GC-MS) analyses and the separation efficiency of the SPE step required in the traditional gas chromatography-isotope dilution mass spectrometry (GC-IDMS) reference methods employed for the determination of serum creatinine. The analysis of real serum samples by GC-MS showed that creatine-creatinine separation by SPE can be a nonquantitative step that may induce creatinine overestimations up to 28% in samples containing high amounts of creatine. Also, a detectable conversion of creatine into creatinine was observed during sample preparation for LC-MS/MS. The developed double-spike LC-MS/MS improves the current state of the art for the determination of creatinine in human serum by isotope dilution mass spectrometry (IDMS), because corrections are made for all the possible errors derived from the sample preparation step.

To study the complications of total laryngectomy, we evaluated 471 previously untreated patients who underwent total laryngectomy between 1980 and 1997. This series consisted of 358 patients with primary carcinoma of the larynx and 113 with carcinoma of the hypopharynx. Concurrent neck dissection was performed in 85% of patients. Complications were studied in relation to age, T and N stage, previous tracheostomy, neck dissection, margins, reconstruction, tracheoesophageal puncture, and surgeon. Complication treatment and hospitalization were also evaluated. The overall complication rate was 30.7%, with 29.2% major and 6.5% minor complications. The mortality rate was 0.6% (3/471). Pharyngocutaneous fistula was the most frequent wound complication (21%), followed by wound infection (4.2%) and hemorrhage (2.3%). Pneumonia (1.4%) and embolism (0.4%) were the most frequent medical complications. Hypopharyngeal tumors, neck dissection, and extended procedures had a significantly higher rate of complications. Complication causes, prevention, and treatment are discussed.

Neurological Diseases (ND) are affecting larger segments of aging population every year. Treatment is dependent on expensive accurate and frequent monitoring. It is well known that ND leave correlates in speech and phonation. The present work shows a method to detect alterations in vocal fold tension during phonation. These may appear either as hypertension or as cyclical tremor. Estimations of tremor may be produced by auto-regressive modeling of the vocal fold tension series in sustained phonation. The correlates obtained are a set of cyclicality coefficients, the frequency and the root mean square amplitude of the tremor. Statistical distributions of these correlates obtained from a set of male and female subjects are presented. Results from five study cases of female voice are also given.

The dramatic impact of neurological degenerative pathologies in life quality is a growing concern. It is well known that many neurological diseases leave a fingerprint in voice and speech production. Many techniques have been designed for the detection, diagnose and monitoring the neurological disease. Most of them are costly or difficult to extend to primary attention medical services. Through the present paper it will be shown how some neurological diseases can be traced at the level of phonation. The detection procedure would be based on a simple voice test. The availability of advanced tools and methodologies to monitor the organic pathology of voice would facilitate the implantation of these tests. The paper hypothesizes that some of the underlying mechanisms affecting the production of voice produce measurable correlates in vocal fold biomechanics. A general description of the methodological foundations for the voice analysis system which can estimate correlates to the neurological disease is shown. Some study cases will be presented to illustrate the possibilities of the methodology to monitor neurological diseases by voice.