A Drastic Shift in Lipid Adducts in Colon Cancer Detected by MALDI-IMS Exposes Alterations in Specific K+ Channels.

Even though colorectal cancer (CRC) is one of the most preventable cancers, it is one of the deadliest, and recent data show that the incidence in people <50 years has unexpectedly increased. While new techniques for CRC molecular classification are emerging, no molecular feature is as yet firmly associated with prognosis. Imaging mass spectrometry (IMS) lipidomic analyses have demonstrated the specificity of the lipid fingerprint in differentiating pathological from healthy tissues. During IMS lipidomic analysis, the formation of ionic adducts is common. Of particular interest is the [Na+]/[K+] adduct ratio, which already functions as a biomarker for homeostatic alterations. Herein, we show a drastic shift of the [Na+]/[K+] adduct ratio in adenomatous colon mucosa compared to healthy mucosa, suggesting a robust increase in K+ levels. Interrogating public databases, a strong association was found between poor diagnosis and voltage-gated potassium channel subunit beta-2 (KCNAB2) overexpression. We found this overexpression in three CRC molecular subtypes defined by the CRC Subtyping Consortium, making KCNAB2 an interesting pharmacological target. Consistently, its pharmacological inhibition resulted in a dramatic halt in commercial CRC cell proliferation. Identification of potential pharmacologic targets using lipid adduct information emphasizes the great potential of IMS lipidomic techniques in the clinical field.

Effect of Acute Stress Glycemic Control and Long-Term Glycemic Control on the Incidence of Post-Operative Infection in Diabetics Undergoing Cardiac Surgery.

Objective Post-operative infection after cardiac surgery causes prolonged hospital stay and increased mortality. In patients with diabetes, peri-operative and pre-operative glycemic control have been associated with increased risk of post-operative infection. Saudi Arabia is the 7th highest country in the world for the prevalence of diabetes. In our surgical population the incidence of diabetes is 77%. We were aware of a high incidence of post-operative infections in our institution. The aim of this work was to assess how peri-operative and pre-operative glycemic control was related to the six-week incidence of post-operative infection. Method We retrospectively collected data for 174 adult patients with diabetes undergoing cardiac surgery between January 2017 and June 2019. For group analysis of peri-operative glycemic control, a mean value of ≤10 mmol/l was categorized as optimal control and a mean value of >10 mmol/l as sub-optimal control. The admission glucose value, the maximum glucose value and glycosylated hemoglobin A1c (HbA1c) were separately recorded. Admission HbA1c was used for optimal long-term control group (HbA1c ≤ 7%) and sub-optimal long-term control group (HbA1c > 7%). Results Of the 174 patients 60 (34%) developed infection in the six-week post-operative period. No statistically significant difference in infections was seen in the optimal peri-operative control group (n = 24, 14%) compared to sub-optimal peri-operative control group (n = 36, 21%; p = 0.113). However, patients with infection had a significantly higher mean glucose (10.4 mmol/l versus 9.9 mmol/l, p = 0.0316) than no infection. Grouping according to their HbA1c: well controlled group (41, 24.0%) and poor control group (130, 76.0%) showed no difference in infections. However, patients with lower HbA1c had better glycemic control as measured by: initial glucose (r = 0.52, p=<0.001); mean peri-operative glucose (r = 0.45, p=<0.001); maximum recorded glucose (r = 0.41, p=<0.001). Conclusion The majority of our patients presented with sub-optimal long-term glycemic control which we linked to poor stress glycemic control perioperatively. Patients with post-operative infections had higher mean peri-operative blood glucose. With the high incidence of diabetes in Saudi Arabia we have demonstrated the importance of good pre-operative assessment which allows tighter peri-operative glycemic control to reduce post-operative morbidity.

Association Between Post-Operative Infection and Blood Transfusion in Cardiac Surgery.

Background Blood transfusion is a commonly used therapy in cardiac surgery, whether it is given during the surgery or in the intensive care unit. It is important to evaluate the risks and benefits of exposure to blood transfusion. The use of blood transfusions can influence patient outcome. Previous studies have implicated blood transfusion as a causative factor in post-operative infection. Objectives We aim to determine the effect of blood transfusion on post-operative infection in cardiac surgery patients at the King Faisal Cardiac Center, Jeddah, Saudia Arabia, from January 2017 to January 2019. Methods The regular six-week follow-up of cardiac surgery patients allowed us to maintain a six-week infection span. The main variables included patient characteristics, operative characteristics, pre-operative hemoglobin, six-week infection, blood transfusion, and clinical outcomes. A logistic regression model was developed to identify patient and procedure variables that were associated with blood transfusion and infection. The baseline variables were entered into the model. Variables with p-value less than 0.05 were considered significant. Results The incidence of transfusion out of 197 patients was 93.4% (n = 184). The occurrence of infection was 31.82% (n = 63). There was no difference in post-operative infection for patients who received blood transfusions compared with those who did not receive blood transfusions (p = 0.902). In comparing patients receiving 1-2 units of red blood cells (RBCs) (48%) and those receiving >2 units of RBCs (52%), there was no significance (p = 0.549). Conclusions There was no association between the incidence of infection and blood transfusion. While there are other reasons for withholding blood, it would not be recommended to do so based on the concern of infection.

Renal Outcome in Patients Undergoing Cardiac Surgery Using Cardiopulmonary Bypass.

Introduction Renal dysfunction is a significant variable in determining the outcome of surgery, such as cardiopulmonary bypass graft and valvular replacement, used to treat cardiovascular diseases. In Saudi Arabia, the incidence of renal failure and diabetes is higher than in most western populations. Our aim is to determine the renal outcome of patients who underwent cardiac surgery at King Faisal Cardiac Center from 2014 to 2017. Methods This a retrospective cohort study using a non-probability consecutive sampling technique for selection of the study population to assess the renal outcome in cardiac surgery patients using cardiopulmonary bypass from May 2014 to June 2017 in King Faisal Cardiac Center, Jeddah. Patients older than 18 years of age undergoing cardiac surgery, with available data, were included. Categorical variables were summarized by percentages and frequencies, and continuous variables by means and standard deviations, or medians and interquartile ranges if their distributions were skewed. Logistic regression was done with post-op renal impairment as the dependent variable and pre-op renal dysfunction, age, gender, smoking status, diabetes, hypertension, dyslipidemia, and cardiopulmonary bypass time as independent variables. Results Our sample size included 244 patients who underwent cardiac surgery in this study period; their mean age was 60.5 (SD =7.5) with a mean body mass index (BMI) of 28.62 (SD=5.19). Among our population, 73% (n = 179) were males and 27% (n =66) were females. Two percent (2%) of patients (n = 5) died within 30 days, 4% of patients (n = 10) with temporary dialysis, 8% of patients (n = 19) with postoperative renal dysfunction, and no patients with permanent dialysis. The data showed a significant relationship between levels of creatinine preoperatively and postoperative renal dysfunction (p-value = 0.0001, OR=1.05, 95% CI of 1.031 to 1.064). Conclusion The main predictor of poor renal outcomes for cardiac surgery is preoperative creatinine. While other factors, such as age, gender, body mass index, cardiopulmonary bypass time, diabetes, hypertension, and dyslipidemia, did not show any risk to the postoperative renal outcome.

On the Determination of Forming Limits in Polycarbonate Sheets.

By proposing an adaptation of the methodology usually used in metal forming, this paper aims to provide a general procedure for determining the forming limits, by necking and fracture, of polymeric sheet. The experimental work was performed by means of Nakajima specimens with different geometries to allow to obtain strains in the tensile, plane, biaxial and equibiaxial states for Polycarbonate sheet with 1 mm of thickness. The application of the time-dependent and flat-valley approaches used in metals has been revealed appropriate to characterize the onset of necking and obtain the forming limits of polycarbonate, despite the stable necking propagation typical of polymeric sheets. An analysis of the evolution of the strain paths along a section perpendicular to the crack allowed for a deeper understanding of the steady necking propagation behaviour and the adoption of the methodology of metals to polymers. The determination of the fracture strains was enhanced with the consideration of the principal strains of the DIC system in the last stage, just before fracture, due to the significant elastic recovery typical of polymeric sheets. As a result of this analysis, accurate formability limits by necking and fracture are obtained for polycarbonate sheet, together with the principal strain space, providing a general framework for analysing incremental sheet forming processes where the knowledge of the fracture limits is relevant.

Confirmation of sub-cellular resolution using oversampling imaging mass spectrometry.

The use of oversampling in MALDI (matrix-assisted laser desorption/ionization) imaging mass spectrometry (IMS) to improve lateral resolution is a common practice. However, its application is still controversial and recent studies reported a spot size-dependent change in the relative intensity of the spectra. Previously, using oversampling, we described the lipidome of the human colon epithelium, a 20-30 µm wide cell monolayer; even assessing the changes occurring within this monolayer associated with complex biological processes. Interestingly, the K-means analysis of those experiments unveiled the presence of a third epithelial cluster that anatomically matched the nuclei position. Taking into account the nucleus size (9-12 µm of diameter) and its distinctive lipidome, we decided to test whether this cluster was really of nuclear origin. Hence, the spectra obtained directly from tissue sections were compared with those recorded from the nuclei isolated from colon biopsies. The highest correlation coefficient was obtained when comparing the spectrum of the isolated nuclei with that of the tissue nuclear cluster, demonstrating the successful identification of the nuclear lipidome in the MALDI-IMS experiments run using oversampling and a lateral resolution of 10 µm/pixel. Importantly, it was established that phosphatidylinositol 38:4 nuclear levels remained stable along the colon crypt. That is, it mimicked neither the regular decrease observed in the epithelium nor the regular increase observed in the stroma, eliminating the chance of inter-pixel contamination. Altogether, besides confirming the usefulness of the oversampling technique, these results strongly reinforce the pivotal role IMS may have in promising fields such as single-cell analysis. Graphical abstract.

The CBS domain protein MJ0729 of Methanocaldococcus jannaschii is a thermostable protein with a pH-dependent self-oligomerization.

CBS domains are small protein motifs, usually associated in tandems, that are involved in binding to adenosyl groups. In humans, several genetic diseases have been associated with mutations in CBS domains, and then, they can be considered as promising targets for the rational design of new drugs. However, there are no structural studies describing their oligomerization states, conformational preferences, and stability. In this work, the oligomerization state, the stability, and conformational properties of the CBS domain protein MJ0729 from Methanocaldococcus jannaschii were explored by using a combination of hydrodynamic (namely, ultracentrifugation, DLS, DOSY-NMR, and gel filtration) and spectroscopic techniques (fluorescence, circular dichroism, NMR, and FTIR). The results indicate that the protein had a pH-dependent oligomerization equilibrium: at pH 7, the dominant species is a dimer, where each monomer is a two-CBS domain protein, and at pH 4.5-4.8, the dominant species is a tetramer, with an oblong shape, as shown by X-ray. Deconvolution of the FTIR spectra indicates that the monomer at physiological pH has 26% alpha-helical structure and 17% beta-sheet, with most of the structure disordered. These results are similar to the percentages of secondary structure of the monomer in the resolved tetrameric X-ray structure (21% of alpha-helical structure and 7% of beta-sheet). At pH 2.5, there was a decrease in the level of secondary structure of the monomer, and formation of intermolecular hydrogen bonds, as shown by FTIR, suggesting the presence of high-molecular weight species. The physiological dimeric species is thermal and chemically very stable with a thermal midpoint of approximately 99 degrees C, as shown by both DSC and FTIR; the GdmCl chemical midpoint of the dimeric species occurs in a single step and was greater than 4 M.

Crystallization and preliminary crystallographic analysis of merohedrally twinned crystals of MJ0729, a CBS-domain protein from Methanococcus jannaschii.

CBS domains are small protein motifs, usually associated in tandem, that are implicated in binding to adenosyl groups. Several genetic diseases in humans have been associated with mutations in CBS sequences, which has made them very promising targets for rational drug design. Trigonal crystals of the CBS-domain protein MJ0729 from Methanococcus jannaschii were grown by the vapour-diffusion method at acidic pH. Preliminary analysis of nine X-ray diffraction data sets using Yeates statistics and Britton plots showed that slight variation in the pH as well as in the buffer used in the crystallization experiments led to crystals with different degrees of merohedral twinning that may vary from perfect hemihedral twinning to perfect tetartohedral twinning.

Efectos de la mezcla oxido nitroso/oxígeno al 70/30 por ciento, sobre el contenido arterial de oxigeno y la curva de disociación de oxihemoglobina / bbnkkkjhh

Se estudio el efecto del N2O sobre la curva de disociación de la oxihemoglobina (CDO) y el contenido arterial de O2 (C2O2) cuando se administra con O2 en una relación 70/30 por ciento (pacientes ASA I y ASA II),mediante la obtención y procesamiento de muestras de sangre arterial cada 5 minutos por 15 minutos, después de iniciada la administración de la mezcla. Utilizamos para la determinación de la P50 el programa para computadora versión 2.0 "The Oxigen Status algorithm", elaborado por Mads y Siggaard-Andersen. Radiometer/Copenhagen, y se realizó el cálculo del contenido arterial de O2 por la siguiente fórmula: CaO2=HgB x 1.34 xSat. O2 + pO2 x 0-0032. En nuestros resultados encontramos una disminución de la P50 con desplazamiento de la (CDO) hacia la izquierda; sin modificaciones significativas del (CaO2).Estos hallasgos no fueron influenciados por modificaciones del pH,pCO2 ni temperatura, ya que estos parámetros se mantuvieron dentro de rangos normales