Phase I Study of High-Dose L-methylfolate in Combination with Temozolomide and Bevacizumab in Recurrent IDH wild-type High-Grade Glioma.

Purpose: IDH mutations in low-grade gliomas (LGGs) results in improved survival and DNA hypermethylation compared to IDH wild-type LGGs. IDH-mutant LGGs become hypomethylated during progression. It's uncertain if methylation changes occur during IDH wild-type GBM progression and if the methylome can be reprogrammed. This phase I study evaluated the safety, tolerability, efficacy and methylome changes after L-methylfolate (LMF) treatment, in combination with temozolomide and bevacizumab in patients with recurrent high-grade glioma. Patients and Methods: Fourteen patients total, 13 with GBM, one with anaplastic astrocytoma, all IDH wild-type were enrolled in the study. All patients received LMF at either 15, 30, 60, or 90 mg daily plus temozolomide (75mg/m2 5 days per month) and bevacizumab (10mg/kg every two weeks). Results: No MTD was identified. LMF treated had mOS of 9.5 months (95% CI, 9.1-35.4) comparable to bevacizumab historical control 8.6 months (95% CI, 6.8-10.8). Six patients treated with LMF survived more than 650 days. Across all treatment doses the most adverse events were diarrhea (7%, 1 patient, grade 2), reflux (7%, 1 patient, grade 2), and dysgeusia (7%, 1 patient, grade 2). In the six brains donated at death, there was a 25% increase in DNA methylated CpGs compared to the paired initial tumor. Conclusions: LMF in combination with temozolomide and bevacizumab was well tolerated in patients with recurrent IDH wild-type high-grade glioma. This small study did not establish a superior efficacy with addition of LMF compared to standard bevacizumab therapy, however, this study did show methylome reprogramming in high-grade glioma.

Red blood cell distribution width in glioblastoma.

INTRODUCTION: Glioblastoma (GBM) is the most common and deadly adult brain tumor. Red blood cell distribution width (RDW) has been found in non-central nervous system neoplasms to be associated with survival. This study aims to assess the prognostic value of pre-operative RDW and trends in RDW over time during the disease course. METHODS: This single-institution retrospective cohort study identified patients ≥ 18 years old with pathology-proved glioblastoma treated between April 2003-May 2017 from an institutional database. A Cox proportional hazards model was developed using known prognostic clinical variables to predict overall survival time; a second model incorporating continuously valued RDW was then created. The additional prognostic value of RDW was assessed with a joint model F-test. The variation of RDW-CV over time was evaluated with linear mixed model of RDW. A post-hoc exploratory analysis was performed to assess the trend in RDW lab value leading up to time of death. RESULTS: 346 adult GBM patients were identified; complete survival data was available for all patients. The addition of RDW to the multivariable Cox proportional hazards model did not increase prognostic value. There was an upward trend in RDW throughout the post-operative disease course. In a post-hoc analysis, there was an upward trend in RDW leading up to the time of death. CONCLUSION: Although RDW has been prognostic of survival for many inflammatory, prothrombotic, and neoplastic diseases, pre-operative RDW was not associated with overall survival in GBM patients. RDW trended upwards throughout the disease course, suggesting possible systemic inflammatory effects of either glioblastoma or treatment.

Effect of Hernia Mesh Weights on Postoperative Patient-Related and Clinical Outcomes After Open Ventral Hernia Repair: A Randomized Clinical Trial.

Importance: Although multiple versions of polypropylene mesh devices are currently available on the market for hernia repair, few comparisons exist to guide surgeons as to which device may be preferable for certain indications. Mesh density is believed to impact patient outcomes, including rates of chronic pain and perception of mesh in the abdominal wall. Objective: To examine whether medium-weight polypropylene is associated with less pain at 1 year compared with heavy-weight mesh. Design, Setting, and Participants: This multicenter randomized clinical trial was performed from March 14, 2017, to April 17, 2019, with 1-year follow-up. Patients undergoing clean, open ventral hernia repairs with a width 20 cm or less were studied. Patients were blinded to the intervention. Interventions: Patients were randomized to receive medium-weight or heavy-weight polypropylene mesh during open ventral hernia repair. Main Outcomes and Measures: The primary outcome was pain measured with the National Institutes of Health (NIH) Patient-Reported Outcomes Measurement Information System (PROMIS) Pain Intensity Short Form 3a. Secondary outcomes included quality of life and pain measured at 30 days, quality of life measured at 1 year, 30-day postoperative morbidity, and 1-year hernia recurrence. Results: A total of 350 patients participated in the study, with 173 randomized to receive heavy-weight polypropylene mesh (84 [48.6%] female; mean [SD] age, 59.2 [11.4] years) and 177 randomized to receive medium-weight polypropylene mesh (91 [51.4%] female; mean [SD] age, 59.3 [11.4] years). No significant differences were found in demographic characteristics (mean [SD] body mass index of 32.0 [5.4] in both groups [calculated as weight in kilograms divided by height in meters squared] and American Society of Anesthesiologists classes of 2-4 in both groups), comorbidities (122 [70.5%] vs 93 [52.5%] with hypertension, 44 [25.4%] vs 43 [24.3%] with diabetes, 17 [9.8%] vs 12 [6.8%] with chronic obstructive pulmonary disease), or operative characteristics (modified hernia grade of 2 in 130 [75.1] vs 140 [79.1] in the heavy-weight vs medium-weight mesh groups). Pain scores for patients in the heavy-weight vs medium-weight mesh groups at 30 days (46.3 vs 46.3, P = .89) and 1 year (30.7 vs 30.7, P = .59) were identical. No significant differences in quality of life (median [interquartile range] hernia-specific quality of life score at 1 year of 90.0 [67.9-96.7] vs 86.7 [65.0-93.3]; median [interquartile range] hernia-specific quality of life score at 30 days, 45.0 [24.6-73.8] vs 43.3 [28.3-65.0]) were found for the heavy-weight mesh vs medium-weight mesh groups. Composite 1-year recurrence rates for patients in the heavy-weight vs medium-weight polypropylene groups were similar (8% vs 7%, P = .79). Conclusions and Relevance: Medium-weight polypropylene did not demonstrate any patient-perceived or clinical benefit over heavy-weight polypropylene after open retromuscular ventral hernia repair. Long-term follow-up of these comparable groups will elucidate any potential differences in durability that have yet to be identified. Trial Registration: ClinicalTrials.gov Identifier: NCT03082391.

Perioperative Blood Transfusions Are Associated With Worse Overall Survival But Not Disease-Free Survival After Curative Rectal Cancer Resection: A Propensity Score-Matched Analysis.

BACKGROUND: The effects of blood transfusions on oncologic outcomes after surgery remain inconclusive. Thus, we examined the association between receiving a perioperative blood transfusion and oncologic outcomes in patients undergoing curative rectal cancer resection. OBJECTIVE: The purpose of this study was to assess the association between receiving a perioperative blood transfusion with disease-free and overall survival in patients undergoing curative resection of clinical stage I to III rectal cancer. We hypothesized that blood transfusion is associated with worse disease-free and overall survival in this patient cohort. DESIGN: This was a retrospective cohort study using a propensity score-matched analysis. SETTINGS: The study involved 6 tertiary academic medical centers in the United States contributing to the United States Rectal Cancer Consortium. PATIENTS: Patients who underwent curative resection for rectal cancer from 2010 to 2018 were included. MAIN OUTCOME MEASURES: The primary outcome was disease-free survival. The secondary outcomes were overall survival, intensive care unit length of stay, hospital length of stay, surgical site infection, and readmission. RESULTS: Of the 924 patients eligible for matching, 312 patients were matched, including 100 patients who received a transfusion and 212 who did not. In a propensity score-matched analysis, receiving a perioperative blood transfusion was not associated with worse 5-year disease-free survival (transfused, 78%; not transfused, 83%; p = 0.32) but was associated with worse 5-year overall survival (transfused 65% vs not transfused 86%; p < 0.001) and increased hospital length of stay (transfused, 9.9 d; not transfused, 7.6 d; p = 0.001). LIMITATIONS: Despite propensity matching, confounding may remain. Propensity matching may limit the power to detect a difference in disease-free survival. CONCLUSIONS: Receiving a perioperative blood transfusion is not associated with worse disease-free survival but is associated with worse overall survival. Such findings are important for clinicians and patients to understand when considering perioperative blood transfusions. See Video Abstract at http://links.lww.com/DCR/B531. LAS TRANSFUSIONES DE SANGRE PERIOPERATORIAS SE ASOCIAN CON UNA PEOR SOBREVIDA GLOBAL, PERO NO CON LA SOBREVIDA LIBRE DE ENFERMEDAD POSTERIOR A LA RESECCIN CURATIVA DEL CNCER DE RECTO UN PUNTAJE DE PROPENSIN POR ANLISIS DE CONCORDANCIA: ANTECEDENTES:El impacto de las transfusiones de sangre en los resultados oncológicos posteriores a la cirugía no son concluyentes. Por lo anterior, estudiamos la asociación entre recibir una transfusión de sangre perioperatoria y los resultados oncológicos en pacientes llevados a resección curativa de cáncer de recto.OBJETIVO:El propósito de este estudio fue evaluar la asociación entre recibir una transfusión de sangre perioperatoria con la sobrevida libre de enfermedad y la sobrevida general en pacientes llevados a resección curativa de cáncer de recto en estadio clínico I-III. Nuestra hipótesis es que la transfusión de sangre se asocia con una peor sobrevida global y libre de enfermedad en esta cohorte de pacientes.DISEÑO:Es un estudio de cohorte retrospectivo que utilizó un puntaje de propensión por análisis de concordancia.AMBITO:El estudio se realizó en seis centros médicos académicos de tercer nivel en los Estados Unidos que contribuían al Consorcio de Cáncer de Recto de los Estados Unidos.PACIENTES:Se incluyeron pacientes que fueron llevados a resección curativa por cáncer de recto entre 2010 y 2018.PRINCIPALES VARIABLES EVALUADAS:El objeitvo principal fue la sobrevida libre de enfermedad. Los objetivos secundarios fueron la sobrevida global, el tiempo de estancia en la unidad de cuidados intensivos, el tiempo de la estancia hospitalaria, la infección del sitio quirúrgico y el reingreso.RESULTADOS:De los 924 pacientes elegibles para el emparejamiento, se emparejaron 312 pacientes, incluidos 100 pacientes que recibieron una transfusión y 212 que no. En el puntaje de propensión por análisis de concordancia, recibir una transfusión de sangre perioperatoria no se asoció con una peor sobrevida libre de enfermedad a 5 años (TRANSFUSIÓN 78%; NO TRANSFUSIÓN 83%; p = 0,32), pero se asoció con una peor sobrevida global a 5 años (TRANSFUSION 65% vs NO TRANSFUSION 86%; p <0,001) y aumento de la estancia hospitalaria (TRANSFUSIÓN 9,9 días; NO TRANSFUSION 7,6 días; p = 0,001).LIMITACIONES:A pesar de la concordancia de propensión, pueden existir desviaciones. El emparejamiento de propensión puede limitar el poder para detectar una diferencia en la sobrevida libre de enfermedad.CONCLUSIONES:Recibir una transfusión de sangre perioperatoria no se asocia con una peor sobrevida libre de enfermedad, pero sí con una peor sobrevida global. Es importante que los médicos y los pacientes comprendan estos hallazgos al considerar las transfusiones de sangre perioperatorias. Consulte Video Resumen en http://links.lww.com/DCR/B531. (Traducción-Dr Lisbeth Alarcon-Bernes).

Robotic-assisted and laparoscopic hernia repair: real-world evidence from the Americas Hernia Society Quality Collaborative (AHSQC).

BACKGROUND: Ventral hernia repair (VHR) is a commonly performed procedure and is especially prevalent in patients who have undergone previous open abdominal surgery: up to 28% of patients who have undergone laparotomy will develop a ventral hernia. There is increasing interest in robotic-assisted VHR (RVHR) as a minimally invasive approach to VHR not requiring myofascial release and in RVHR outcomes relative to outcomes associated with laparoscopic VHR (LVHR). We hypothesized real-world evidence from the Americas Hernia Society Quality Collaborative (AHSQC) database will indicate comparable clinical outcomes from RVHR and LVHR approaches not employing myofascial release. METHODS: Retrospective, comparative analysis of prospectively collected data describing laparoscopic and robotic-assisted elective ventral hernia repair procedures reported in the multi-institutional AHSQC database. A one-to-one propensity score matching algorithm identified comparable groups of patients to adjust for potential selection bias that could result from surgeon choice of repair approach. RESULTS: Matched data describe preoperative characteristics and perioperative outcomes in 615 patients in each group. The following significant differences were observed among the 11 outcomes that were pre-specified. Operative time tended to be longer for the RVHR group compared to the LVHR group (p < 0.001). Length of stay differed between the two groups; while both groups had a median length of stay of 0, stay lengths tended to be longer in the LVHR group (p < 0.001). Rates of conversion to laparotomy were fewer for the RVHR group: < 1% and 2%, respectively (p = 0.007). Through 30 days, there were fewer RVHR patient-clinic visits (p = 0.038). CONCLUSION: Both RVHR and LVHR perioperative results compare favorably with each other in most measures. Differences favored RVHR in terms of shorter LOS, fewer conversions to laparotomy, and fewer postoperative clinic visits; differences favored LVHR in terms of shorter operative times.

Advantages of a Fixation-Free Technique for Open Retromuscular Ventral Hernia Repair.

BACKGROUND: In open retromuscular ventral hernia repair, fixation-free mesh placement is increasingly prevalent and may minimize pain; the main concern with this technique is short-term technical failure and hernia recurrence. This study compared outcomes following mechanical mesh fixation (i.e., sutures, staples, tacks) versus fixation-free mesh placement. METHODS: Adults who underwent open, elective, retromuscular ventral hernia repair of 15 cm width or less with permanent synthetic mesh placement in a clean wound were identified. Propensity score matching was used to compare patients who received mechanical mesh fixation to those who received fixation-free mesh placement. Thirty-day hernia recurrence was the primary outcome, with secondary outcomes of 30-day hospital length of stay and 30-day rates of readmission, reoperation, wound events, pain, and abdominal wall function. One- and 2-year composite recurrence and 3-year cumulative composite recurrence were also evaluated. RESULTS: A 3:1 propensity score match was performed on 299 fixation-free patients identifying 897 mechanical fixation patients, with a mean body mass index of 31 kg/m and mean age of 57.5 years. There was no difference in 30-day recurrence between mechanical and fixation-free approaches (0.2 percent versus 0 percent; p = 1). Median length of stay was longer for mechanical fixation (4 versus 3 days; p = 0.002). In the mechanical fixation group, pain scores were higher (worse pain, 46 versus 44; p = 0.001), and abdominal wall function scores were lower (worse function, 47 versus 60; p = 0.003), with no differences in rates of hospital readmission, reoperation, or wound events. There were no differences in long-term outcomes of 1- and 2-year composite recurrence, or 3-year cumulative composite recurrence. CONCLUSION: For short-term technical durability, fixation-free mesh placement in open retromuscular ventral hernia repair is an acceptable alternative to mechanical fixation for hernia defects of 15 cm or less. CLINICAL QUESTION/LEVEL OF EVIDENCE: Therapeutic, III.

Trust as a Predictor of Patient Perceptions Regarding Overlapping Surgery and Trainee Independence.

OBJECTIVES: To examine opinions on trainee independence and attending presence among a cross-section of the general population and explore how perceptions of trust, past experiences, and demographics interacted with comfort consenting to these surgical scenarios. STUDY DESIGN: Mixed-methods METHODS: Based on prior qualitative analysis, we designed a survey of patient preferences and values that focused on trust in healthcare practitioners and processes, which also included comfort ratings of three surgical scenarios (including overlapping surgery). The survey was administered to a sample from the general public using Mechanical Turk. We identified discreet domains of trust and examined the association of responses to these domains with comfort ratings, prior healthcare experiences, and demographics. RESULTS: We analyzed 225 surveys and identified four patient subgroups based on responses to the surgical scenarios. Subjects that were more comfortable with overlapping surgery were more trusting of trainees and delegation by the attending. Past experiences in healthcare (positive and negative) were associated with multiple domains of trust (in trainees, surgeons, and the healthcare system). Demographics were not predictive of trust responses or comfort ratings. CONCLUSION: Patients express varying degrees of comfort with overlapping surgery, and this is not associated with demographics. Past negative experiences have an impact on trust in the healthcare system overall, and trust in trainees specifically predicts comfort with attending absence from the operating room. Efforts to increase patient comfort with overlapping surgery and surgical training should include strategies to address past negative experiences and foster trust in trainees and the delegation process. LEVEL OF EVIDENCE: IV Laryngoscope, 130:2728-2735, 2020.

Religion, Spirituality, and Risk of End-Stage Kidney Disease Among Adults of Low Socioeconomic Status in the Southeastern United States.

BACKGROUND: Religiosity, encompassing spirituality and religious practices, is associated with reduced disease incidence among individuals of low socioeconomic status and who self-identify as Black. We hypothesized that religiosity associates with reduced end-stage kidney disease (ESKD) risk among Black but not White adults of low socioeconomic status. DESIGN: Cox models of religiosity and ESKD risk in 76,443 adults. RESULTS: Black adults reporting high spirituality had reduced ESKD risk after adjusting for demographic characteristics [Hazard Ratio (HR) .82 (95% Confidence Interval (CI)) (.69-.98)], depressive symptoms, social support, and tobacco use [HR .81 (CI .68-.96)]. When clinical covariates were added, associations between spirituality and ESKD were slightly attenuated and lost significance [HR .85 (CI .68-1.06)]. Associations were not demonstrated among White adults. CONCLUSIONS: Spirituality associates with reduced ESKD risk among Black adults of low socioeconomic status independent of demographic, psychosocial, and behavioral characteristics. Effect modification by race was not statistically significant.

Comparing pathologic outcomes for robotic versus laparoscopic Surgery in rectal cancer resection: a propensity adjusted analysis of 7616 patients.

BACKGROUND: Margin negative resection of rectal cancer with minimally invasive techniques remains technically challenging. Robotic surgery has potential advantages over traditional laparoscopy. We hypothesize that the difference in the rate of negative margin status will be < 6% between laparoscopic and robotic approach. METHODS: The National Cancer Database (2010-2014) was queried for adults with locally advanced rectal cancer who underwent neoadjuvant chemoradiation and curative resection to conduct an observational retrospective cohort study of a prospectively maintained database. Patients were grouped by either robotic (ROB) or laparoscopic (LAP) approach in an intent-to-treat analysis. Primary outcome was negative margin status, defined as a composite of circumferential resection margin and distal margin. Secondary outcomes included length of stay (LOS), readmission, 90-day mortality, and overall survival. RESULTS: 7616 patients with locally advanced rectal cancer who underwent minimally invasive resection were identified. 2472 (32%) underwent attempted robotic approach. The overall conversion rate was 13% and was increased in the laparoscopic group [LAP: 15% vs. ROB: 8%; OR 0.47; 95% CI (0.39, 0.57)]. Differences in margin negative resection rate were within the prespecified range of practical equivalence (LAP: 93% vs.: ROB 94%; 95% CI (0.69, 1.06); [Formula: see text] = 1). For secondary outcomes, there was no difference in 30-day readmission [LAP: 9% vs.: ROB 8%; 95% CI (0.84, 1.24)] and 90-day mortality [LAP: 1% vs.: ROB 1%; 95% CI (0.38, 1.24)]. While the median LOS was 5 days in both groups, the mean LOS was 0.6 (95% CI: 0.24, 0.89) days shorter in the robotic group. CONCLUSION: This robust analysis supports either robotic or laparoscopic approach for resection of locally advanced rectal cancer from a margin perspective. Both have similar readmission and 5-year overall survival rates. Patients undergoing robotic surgery have a 0.6-day decrease in LOS and decreased conversion rate.

The effect of increasing body mass index on wound complications in open ventral hernia repair with mesh.

BACKGROUND: There is a paucity of data delineating the relationship between body mass index (BMI) and wound complications. We investigated the association between BMI and wound morbidity following open ventral hernia repair with mesh (OVHR). DESIGN: Patients undergoing elective OVHR were identified within the Americas Hernia Society Quality Collaborative. Multivariate logistic regression identified predictors of 30-day surgical site infection (SSI) and surgical site occurrences requiring procedural intervention (SSOPI). BMI was treated as a continuous variable in the models. RESULTS: 8949 patients were included (median age 58, median BMI 31.3 kg/m2, median defect width of 7 cm). Repairs typically included synthetic mesh (89%), placed as a sublay (70%). SSI rate was 4.5% and SSOPI was 6.7%. BMI was associated with increased relative log-odds for SSI (p = 0.01) and SSOPI (<0.0001), with a proportional increase in relative log-odds for complications according to escalations in BMI. CONCLUSION: Escalating BMI progressively increases relative log-odds for SSI and SSOPI after OVHR. Further studies are necessary to determine whether preoperative weight loss can reduce the impact of this association.

Insulin resistance is a significant determinant of sarcopenia in advanced kidney disease.

Maintenance hemodialysis (MHD) patients display significant nutritional abnormalities. Insulin is an anabolic hormone with direct effects on skeletal muscle (SM). We examined the anabolic actions of insulin, whole-body (WB), and SM protein turnover in 33 MHD patients and 17 participants without kidney disease using hyperinsulinemic-euglycemic-euaminoacidemic (dual) clamp. Gluteal muscle biopsies were obtained before and after the dual clamp. At baseline, WB protein synthesis and breakdown rates were similar in MHD patients. During dual clamp, controls had a higher increase in WB protein synthesis and a higher suppression of WB protein breakdown compared with MHD patients, resulting in statistically significantly more positive WB protein net balance [2.02 (interquartile range [IQR]: 1.79 and 2.36) vs. 1.68 (IQR: 1.46 and 1.91) mg·kg fat-free mass-1·min-1 for controls vs. for MHD patients, respectively, P < 0.001]. At baseline, SM protein synthesis and breakdown rates were higher in MHD patients versus controls, but SM net protein balance was similar between groups. During dual clamp, SM protein synthesis increased statistically significantly more in controls compared with MHD patients ( P = 0.03), whereas SM protein breakdown decreased comparably between groups. SM net protein balance was statistically significantly more positive in controls compared with MHD patients [67.3 (IQR: 46.4 and 97.1) vs. 15.4 (IQR: -83.7 and 64.7) µg·100 ml-1·min-1 for controls and MHD patients, respectively, P = 0.03]. Human SM biopsy showed a positive correlation between glucose and leucine disposal rates, phosphorylated AKT to AKT ratio, and muscle mitochondrial markers in controls but not in MHD patients. Diminished response to anabolic actions of insulin in the stimulated setting could lead to muscle wasting in MHD patients.

Metabolic Effects of Diet and Exercise in Patients with Moderate to Severe CKD: A Randomized Clinical Trial.

CKD is steadily increasing along with obesity worldwide. Furthermore, obesity is a proinflammatory risk factor for progression of CKD and cardiovascular disease. We tested the hypothesis that implementation of caloric restriction and aerobic exercise is feasible and can improve the proinflammatory metabolic milieu in patients with moderate to severe CKD through a pilot, randomized, 2×2 factorial design trial. Of 122 participants consented, 111 were randomized to receive caloric restriction and aerobic exercise, caloric restriction alone, aerobic exercise alone, or usual care. Of those randomized, 42% were women, 25% were diabetic, and 91% were hypertensive; 104 started intervention, and 92 completed the 4-month study. Primary outcomes were a change from baseline in absolute fat mass, body weight, plasma F2-isoprostane concentrations, and peak oxygen uptake (VO2 peak). Compared with usual care, the combined intervention led to statistically significant decreases in body weight and body fat percentage. Caloric restriction alone also led to significant decreases in these measures, but aerobic exercise alone did not. The combined intervention and each independent intervention also led to significant decreases in F2-isoprostane and IL-6 concentrations. No intervention produced significant changes in VO2 peak, kidney function, or urine albumin-to-creatinine ratio. In conclusion, 4-month dietary calorie restriction and aerobic exercise had significant, albeit clinically modest, benefits on body weight, fat mass, and markers of oxidative stress and inflammatory response in patients with moderate to severe CKD. These results suggest healthy lifestyle interventions as a nonpharmacologic strategy to improve markers of metabolic health in these patients.

Tissue sodium accumulation and peripheral insulin sensitivity in maintenance hemodialysis patients.

BACKGROUND: Recent data suggest that sodium (Na+ ) is stored in the muscle and skin without commensurate water retention in maintenance hemodialysis (MHD) patients. In this study, we hypothesized that excessive Na+ accumulation would be associated with abnormalities in peripheral insulin action. METHODS: Eleven MHD patients and eight controls underwent hyperinsulinemic-euglycemic-euaminoacidemic clamp studies to measure glucose (GDR) and leucine disposal rates (LDR), as well as lower left leg 23 Na magnetic resonance imaging to measure Na+ concentration in the muscle and skin tissue. RESULTS: The median GDR and LDR levels were lower, and the median muscle Na+ concentration was higher in MHD patients compared with controls. No significant difference was found regarding skin Na+ concentration between group comparisons. Linear regression revealed inverse relationships between muscle Na+ concentration and GDR and LDR in MHD patients, whereas no relationship was observed in controls. There was no association between skin Na+ content and GDR or LDR in either MHD patients or controls. CONCLUSIONS: These data suggest that excessive muscle Na+ content might be a determinant of IR in MHD patients, although the causality and mechanisms remain to be proven.

The LKB1 tumor suppressor as a biomarker in mouse and human tissues.

Germline mutations in the LKB1 gene (also known as STK11) cause the Peutz-Jeghers Syndrome, and somatic loss of LKB1 has emerged as causal event in a wide range of human malignancies, including melanoma, lung cancer, and cervical cancer. The LKB1 protein is a serine-threonine kinase that phosphorylates AMP-activated protein kinase (AMPK) and other downstream targets. Conditional knockout studies in mouse models have consistently shown that LKB1 loss promotes a highly-metastatic phenotype in diverse tissues, and human studies have demonstrated a strong association between LKB1 inactivation and tumor recurrence. Furthermore, LKB1 deficiency confers sensitivity to distinct classes of anticancer drugs. The ability to reliably identify LKB1-deficient tumors is thus likely to have important prognostic and predictive implications. Previous research studies have employed polyclonal antibodies with limited success, and there is no widely-employed immunohistochemical assay for LKB1. Here we report an assay based on a rabbit monoclonal antibody that can reliably detect endogenous LKB1 protein (and its absence) in mouse and human formalin-fixed, paraffin-embedded tissues. LKB1 protein levels determined through this assay correlated strongly with AMPK phosphorylation both in mouse and human tumors, and with mRNA levels in human tumors. Our studies fully validate this immunohistochemical assay for LKB1 in paraffin-embedded formalin tissue sections. This assay should be broadly useful for research studies employing mouse models and also for the development of human tissue-based assays for LKB1 in diverse clinical settings.