Parascapular Flap for Severe Hidradenitis Suppurativa.

Hidradenitis suppurativa is a chronic inflammatory disease which affects apocrine glands and hair follicles of the skin, primarily in the axillary and groin regions. This condition can be highly debilitating, causing painful lesions and a negative psychological impact on patients. While medical and minimally invasive treatments are available, surgical intervention may be necessary for severe cases. In cases involving axillary defects, the use of local flaps such as the parascapular flap is a viable option. In this case report, we present a 34-year-old woman who presented to our clinic with a history of recurrent abscesses and cutaneous infections in the axillary region. After thorough evaluation, we chose to use the parascapular flap for reconstruction. The parascapular flap is a one-stage procedure that allows for extensive resection of the axillary area without resulting in contractions or retractions over the long term. Additionally, this technique allows for preservation of the axilla's original shape with minimal donor site morbidity.

Recurrent Pediatric Extranasopharyngeal Angiofibroma of the Epiglottis: Case Report.

Angiofibroma is a non-encapsulated, highly vascular tumor that usually originates in the nasopharynx. Laryngeal cases of extranasopharyngeal angiofibroma (ENA) are a very rare pathology, especially in children. Only eight ENA laryngeal cases have been described in the literature, and only one of them is a pediatric case. In this report we present an 11-year-old child with epiglottic ENA resected with transoral endoscopic ultrasonic surgery (TOUSS) with review of the literature. Because of reccurrence after five months he underwent re-excision with CO2 laser. Recurrences in ENA are infrequent, but as demonstrated in our case, close endoscopic follow-up is mandatory in this location. Endoscopic hemostatic procedures like TOUSS and CO2 laser ensure bloodless surgery for the management of this type of vascular laryngeal tumors.

Complicaciones ORL severas por mononucleosis infecciosa en adolescentes sanos: 2 casos clínicos y revisión de la literatura / ENT severe complications of infectious mononucleosis in healthy adolescents: report of two cases and literature review

Resumen La mononucleosis infecciosa (MI) es un cuadro clínico generalmente benigno y autolimitado en la infancia y adolescencia debido a la primoinfección del virus de Epstein-Barr caracterizado por la triada de faringitis, fiebre y adenopatías. El riesgo de complicaciones aumenta con la edad y la inmunosupresión, siendo las complicaciones letales más frecuentes las asociadas a rotura esplénica, alteraciones neurológicas y obstrucción de la vía aérea por el aumento del tamaño amigdalar. Los abscesos cervicales asociados a MI son poco frecuentes, siendo mayoritariamente periamigdalinos e intraamigdalares. Presentamos dos casos quirúrgicos de abscesos cervicales profundos de gran tamaño con afectación retrofaríngea y parafaríngea en adolescentes sanos de corta edad (14 y 15 años), sin ningún tipo de inmunosupresión o factores de riesgo, uno de ellos asociado además, a una relevante hemorragia amigdalar espontanea, condición no descrita previamente en la literatura en relación a MI en un paciente tan joven.

Abstract Infectious mononucleosis (MI) is a generally benign and self-limited condition in childhood and adolescence due to the primary EBV infection characterized by the triad of pharyngitis, fever, and lymphadenopathies. The risk of complications increases with age and immunosuppression. The most frequent fatal complications are those associated with splenic rupture, neurological alterations, and airway obstruction due to increased tonsillar size. Cervical abscesses associated with MI are rare, being mostly peritonsillar and intra-tonsil. We present two surgical cases of big deep cervical abscesses with retropharyngeal and parapharyngeal involvement in healthy very young adolescents (14 and 15 years old), without any type of immunosuppression or risk factors, one of them associated with a clinically relevant spontaneous tonsillar bleeding, which had not been described in the literature associated with MI in such young patient.

Androgen-Dependent Prostate Cancer Cells Reprogram Their Metabolic Signature upon GLUT1 Upregulation by Manganese Superoxide Dismutase.

Prostate cancer is the second leading cause of cancer in men across the globe. The prostate gland accounts for some unique glycolytic metabolic characteristics, which causes the metabolic features of prostate tumor initiation and progression to remain poorly characterized. The mitochondrial superoxide dismutase (SOD2) is one of the major redox metabolism regulators. This study points out SOD2 as one major regulator for both redox and glycolytic metabolism in prostate cancer. SOD2 overexpression increases glucose transporter GLUT-1 and glucose uptake. This is not an insulin-mediated effect and seems to be sex-dependent, being present in male mice only. This event concurs with a series of substantial metabolic rearrangements at cytoplasmic and mitochondrial level. A concomitant decrease in glycolytic and pentose phosphate activity, and an increase in electron transfer in the mitochondrial electronic chain, were observed. The Krebs Cycle is altered to produce amino-acid intermediates by decreasing succinate dehydrogenase. This in turn generates a 13-fold increase in the oncometabolite succinate. The protein energy sensor AMPK is decreased at basal and phosphorylated levels in response to glucose deprivation. Finally, preliminary results in prostate cancer patients indicate that glandular areas presenting high levels of SOD2 show a very strong correlation with GLUT-1 protein levels (R2 = 0.287 p-value < 0.0001), indicating that in patients there may exist an analogous phenomenon to those observed in cell culture and mice.

TransOral UltraSonic surgery (TOUSS) for oral cavity, oropharyngeal and supraglottic malignancy: A prospective study of feasibility, safety, margins, functional and survival outcomes.

INTRODUCTION/BACKGROUND: With the advent of TransOral Robotic Surgery (TORS) the ease of transoral procedures has been dramatically improved. TORS is already established for its feasibility, functional and oncological outcomes for selected lesions of oral cavity, oropharynx and laryngopharynx. This study reports on preliminary results with TransOral UltraSonic Surgery (TOUSS) for oncologic resections of oral cavity, oropharyngeal and supraglottic malignancies. MATERIALS AND METHODS: Eighteen patients with malignancies of oral cavity, oropharynx and supraglottis underwent TOUSS with simultaneous neck dissection and adjuvant therapy as indicated, from January 2018 to April 2019. Essential equipment included the FK-retractor (Gyrus Medical, Tuttilngen, Germany) for TransOral exposure, the Olympus ENDOEYE Flex 5 mm 2D/10 mm 3D deflecting tip video laparoscopes, and 35 cm long ultrasonic harmonic scalpel (Thunderbeat). Parameters evaluated include tumor staging, mouth opening, TOUSS setup time, TOUSS primary removal time, surgical margins, blood transfusions, tracheostomy, postoperative complications, enteral feeding and resumption of oral diet, duration of hospital stay, and survival outcomes. RESULTS: Eighteen patients underwent complete TransOral UltraSonic Surgery (TOUSS), with simultaneous unilateral or bilateral neck dissection. No procedure was abandoned intraoperatively due to difficulty in extirpation of the tumor. Margins were negative for ten patients (55.6%), close in five (27.8%), and positive in three patients (16.7%). Average TOUSS set-up time was 22.5 min (range, 10-30 min) and average TOUSS primary tumor removal time was 35.3 min (range, 15-60 min). Patients started tolerating oral feeds even in the second post op day (mean 6 days), and transitioning to complete oral feeds with removal of the nasogastric tube was achieved in all (mean, 16 days). The average hospital stay was 7.4 days (range 2-16 days). Secondary hemorrhage occurred in two cases and required an emergency tracheostomy and ligation of lingual artery. Minor cervicopharyngeal fistula occurred in four cases and settled in all with conservative non-surgical treatment. Overall survival at 3 years was 70.5%, and disease-specific survival was 94.4%. CONCLUSION: TransOral UltraSonic Surgery (TOUSS) is a safe and sound alternative method of endoscopic surgical treatment of oral cavity, oropharynx and supraglottic neoplasms. Advantages of this technique include faster resection time, intraoperative assistance from Narrow Band Imaging, easy affordability compared to TORS, and excellent functional outcomes.

The CO2 waveguide laser with flexible fiber in transoral resection of oral and oropharyngeal cancers: a retrospective cohort study on postoperative and quality of life outcomes.

The aim of this study was to evaluate the CO2 waveguide laser (WG CO2 laser) with flexible fiber (Lumenis Ltd., Yokneam, Israel) in the treatment of oral and oropharyngeal cancers, specifically focusing on postoperative outcomes, pain, and quality of life (QoL). Eighty-one patients, 43 women and 38 men, with oral or oropharyngeal cancer who consecutively underwent transoral resection by WG CO2 laser from August 2015 to April 2020 were retrospectively enrolled. Resections were performed in super pulsed mode with a power setting ranging between 3 and 10 W. Data about frozen sections, reconstruction, complication rate, length of hospital stay, tracheostomy rate and time to decannulation, nasogastric feeding tube rate and time to oral feeding, pain, and QoL were reviewed. Continuous variables were presented as mean and standard deviation. Concordance between intraoperative frozen section examination and definitive histology was calculated using Cohen's K test of agreement. The mean length of hospital stay was 13 days. The feeding tube rate was 81%; the tracheostomy rate was 35%; the feeding tube was left in place for 8 days on average, and the time to decannulation was 9 days. The only complication was a postoperative bleeding in 4 patients. The median postoperative pain score measured by the Numeric Pain Rating Scale on postoperative days 1, 3, and 5 was 0 and there was a constant decrease in painkiller use over the days. The overall mean composite QoL score was 77 ± 14, with excellent results in saliva, taste, pain, and speech domains. Frozen section evaluation had a specificity of 99% and a negative predictive value of 98%. WG CO2 laser is a good and safe tool for transoral tailored resection of oral and oropharyngeal cancers. It ensures a good overall QoL and guarantees fast recovery and a very low postoperative pain.

Salvage total laryngectomy: is a flap necessary? / Laringectomia total de resgate: o uso de retalho é necessário?

Abstract 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.

Salvage total laryngectomy: is a flap necessary?

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.

Frozen sections and complete resection in oral cancer surgery.

OBJECTIVES: Although the reliability of frozen sections for the intraoperative assessment of complete tumour excision has been established, the best location for collection and the impact of the type of sampling are still debated. We retrospectively investigated the reliability of frozen sections when collected from the surgical bed as tissue strips representative of the whole superficial margin and as a bowl of tissue underlying the resection site for deep margin, and the possibility of relying on frozen section negativity to consider resections complete. MATERIALS AND METHODS: Frozen section reliability was calculated by comparing histology before and after formalin embedding and then categorised by sampling type, in 182 patients undergoing transoral resection of oral cancer. RESULTS: Comparing frozen and permanent histology, sensitivity, specificity and accuracy were 69%, 98% and 96%, respectively; categorisation by sampling type failed to produce statistically significant differences. Based on frozen section negativity after formalin embedding, complete resections were obtained in 91.7% of patients with multiple-strip and bowl frozen sections. CONCLUSION: Frozen sections collected as tissue strips and bowl are as reliable as point sampling in the intraoperative guidance of surgical resections. They effectively provide for margin enlargement, thereby increasing the surgeon's confidence that negative margins are clear.

Is there a role for ultrasonic surgery in transoral laryngeal cancer resections?

INTRODUCTION: Minimally invasive surgery for laryngeal cancer is nowadays the goal of all larynx surgeons. Transoral laser microsurgery is a widespread and standardized technique that has made it possible to reduce surgical morbidities and hospitalization and to spare laryngeal function. Nonetheless, it has some limitations, which may be exceeded by using new optical and cutting devices as in TransOral UltraSonic Surgery. Areas covered: The aim of this paper is to identify current knowledge about ultrasonic scalpel (US) application in transoral laryngeal surgery and to deduce reasonable indications and contraindications of the tool. Expert opinion: Transoral laryngeal surgery with US is feasible and allows for 'angulated' dissections with higher hemostatic capacity than the CO2 laser. When coupled with an endoscope, surgeons have the possibility to angulate the laryngeal exposure from the inside, reducing blind areas. Nonetheless, US blades are quite bulky, thermal damage is higher than that produced by CO2 laser, and its use should be avoided where the functional result is more closely related to the amount of resected tissue. Tumors limited to the suprahyoid larynx are the current indications for US surgery.

Melatonin Decreases Glucose Metabolism in Prostate Cancer Cells: A 13C Stable Isotope-Resolved Metabolomic Study.

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.

Accurate and sensitive determination of molar fractions of 13C-Labeled intracellular metabolites in cell cultures grown in the presence of isotopically-labeled glucose.

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.

A simplified calculation procedure for mass isotopomer distribution analysis (MIDA) based on multiple linear regression.

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.

Minimally invasive video-assisted submandibular sialadenectomy: surgical technique and results from two institutions.

BACKGROUND: Submandibular gland excision is traditionally performed using a transcervical approach. However, innovative surgical trials have recently been conducted to investigate techniques that can prevent or reduce visible scarring and nerve injury. The aim of the present study was to evaluate the feasibility of a new approach to submandibular gland excision that is based on the use of a minimally invasive video-assisted technique and an ultrasound scalpel in an endoscopic neck surgery program with a low annual flow of procedures. METHODS: We retrospectively studied 15 patients with submandibular gland disease who underwent minimally invasive video-assisted submandibular sialadenectomy performed by two surgeons at two institutions. Eight patients had proximally located salivary calculi, three had chronic sialadenitis, and four had benign neoplasms. All dissections were carried out by a single-port gasless approach, using the Miccoli technique, involving endoscope magnification and an ultrasonic scalpel. RESULTS: All 15 submandibular gland resections were performed successfully, with no conversions to conventional open resection. The operative time ranged from 45 to 125 min (median 84 min). A total of 67 % of patients were discharged the day after surgery, and the maximum length of stay was 3 days. One patient experienced postoperative bleeding, and one experienced postoperative infection. There was no neural injury. The incision scar healed well in all cases, and all patients reported excellent cosmetic results. CONCLUSIONS: Endoscopic submandibular gland resection using a minimally invasive video-assisted technique, endoscopic magnification, and ultrasonic scalpel was feasible and resulted in excellent surgical outcomes.

Transoral ultrasonic total laryngectomy (TOUSS-TL): description of a new endoscopic approach and report of two cases.

The minimally invasive total laryngectomy avoids a wide surgical field and so it has the potential benefit of reducing the local morbidity, especially on radiated patients. This approach has been previously described on a robotic basis, the transoral robotic total laryngectomy (TORS-TL). We have designed a minimally invasive approach for total laryngectomy (TL) using the transoral ultrasonic surgery technique (TOUSS). TOUSS is a transoral, endoscopic, non-robotic approach for laryngeal and pharyngeal tumors, based on the ultrasonic scalpel as a resection tool. Two patients with a laryngeal squamous cell carcinoma with indication for total laryngectomy were surgically treated: one primary TL for a subglottic carcinoma and one salvage TL with partial pharyngectomy for a local relapse after chemoradiotherapy of a glottic carcinoma. The tumors were completely removed with free surgical margin in both patients. The functional recovery was satisfactory in terms of swallowing and speech (a tracheoesophageal puncture and voice prosthesis placement were done in the same procedure). No intraoperative complications were observed. The patient with previous chemoradiotherapy had a pharyngocutaneous fistula which closed spontaneously without additional surgery. We have demonstrated that transoral endoscopic approach to the larynx and pharynx is feasible without a robotic platform. TOUSS-TL can easily spread the transoral endoscopic philosophy as well as the benefits of a minimally invasive way to remove the entire larynx. Further research will show the advantages in terms of complications and functional outcomes.

Simultaneous determination of creatinine and creatine in human serum by double-spike isotope dilution liquid chromatography-tandem mass spectrometry (LC-MS/MS) and gas chromatography-mass spectrometry (GC-MS).

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.

TransOral endoscopic UltraSonic Surgery (TOUSS): a preliminary report of a novel robotless alternative to TORS.

The objective of this study is to describe and evaluate the feasibility of TransOral UltraSonic Surgery (TOUSS), a new endoscopic alternative to transoral robotic surgery for approaching pharyngeal and laryngeal tumours based on ultrasonic scalpel as a resection tool. This is a prospective study on 11 consecutive patients with pharyngeal and supraglottic carcinomas between December 2013 and August 2014. All tumours were resected transorally with 35 cm ThunderbeatTM. Exposure was achieved using GyrusTM FK-retractor and Olympus ENDOEYE Flex 5 mm 2D/10 mm 3D deflecting tip video laparoscopes. We evaluated tumour staging, surgical margins, surgical time, blood transfusions, tracheostomy, enteral feeding, postoperative pain and hospital stay. The operating room setup and procedure are described. This series comprised seven early and four locally advanced carcinomas. The mean setup for TOUSS and resection time were 16 and 70.9 minutes. No major intraoperative complications were identified. The average time of nasogastric feeding tube dependence (n = 9) was 13 days. Gastrostomy was performed in one patient. The average hospital stay was 14.3 days. Postoperative pain was satisfactory treated with nonsteroidal anti-inflammatory drugs. We have described TOUSS as a new feasible and intuitive procedure to approach endoscopically pharyngeal and supraglottic tumours, with good intraoperative conditions and functional outcomes.

Development of an isotope dilution GC-MS procedure for the routine determination of creatinine in complex serum samples.

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.

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