Stress - Regulation of SUMO conjugation and of other Ubiquitin-Like Modifiers.

Stress is unavoidable and essential to cellular and organismal evolution and failure to adapt or restore homeostasis can lead to severe diseases or even death. At the cellular level, stress drives a plethora of molecular changes, of which variations in the profile of protein post-translational modifications plays a key role in mediating the adaptative response of the genome and proteome to stress. In this context, post-translational modification of proteins by ubiquitin-like modifiers, (Ubl), notably SUMO, is an essential stress response mechanism. In this review, aiming to draw universal concepts of the Ubls stress response, we will decipher how stress alters the expression level, activity, specificity and/or localization of the proteins involved in the conjugation pathways of the various type-I Ubls, and how this result in the modification of particular Ubl targets that will translate an adaptive physiological stress response and allow cells to restore homeostasis.

Biochemical characterization of SUMO-conjugating enzymes by in vitro sumoylation assays.

The small ubiquitin-related modifier (SUMO) is a protein of ~10kDa that is covalently conjugated to its substrate proteins in an enzymatic process called sumoylation. This posttranslational modification is an essential regulatory mechanism that plays crucial roles in many cellular pathways. It allows rapid adaptation to environmental changes by switching protein functions due to alternate complex assemblies, changes in intracellular localization, enzymatic activity, or stability. SUMO conjugation is executed by the hierarchical action of E1, E2, and E3 enzymes. Both E2 and E3 enzymes contribute to substrate specificity but with E3 ligases being the more important for this. E1 and E2 activities are essential for all sumoylation reactions but usually-with a few exceptions-modify substrates only inefficiently. Hence, most substrates require the additional action of an E3 ligase or a cofactor. Here, we describe methods to distinguish a bona fide E3 ligase from a cofactor activity by using in vitro sumoylation assays.

Modulation of hepatic inflammation and energy-sensing pathways in the rat liver by high-fructose diet and chronic stress.

PURPOSE: High-fructose consumption and chronic stress are both associated with metabolic inflammation and insulin resistance. Recently, disturbed activity of energy sensor AMP-activated protein kinase (AMPK) was recognized as mediator between nutrient-induced stress and inflammation. Thus, we analyzed the effects of high-fructose diet, alone or in combination with chronic stress, on glucose homeostasis, inflammation and expression of energy sensing proteins in the rat liver. METHODS: In male Wistar rats exposed to 9-week 20% fructose diet and/or 4-week chronic unpredictable stress we measured plasma and hepatic corticosterone level, indicators of glucose homeostasis and lipid metabolism, hepatic inflammation (pro- and anti-inflammatory cytokine levels, Toll-like receptor 4, NLRP3, activation of NFκB, JNK and ERK pathways) and levels of energy-sensing proteins AMPK, SIRT1 and peroxisome proliferator-activated receptor gamma coactivator-1 alpha (PGC-1α). RESULTS: High-fructose diet led to glucose intolerance, activation of NFκB and JNK pathways and increased intrahepatic IL-1ß, TNFα and inhibitory phosphorylation of insulin receptor substrate 1 on Ser307. It also decreased phospho-AMPK/AMPK ratio and increased SIRT1 expression. Stress alone increased plasma and hepatic corticosterone but did not influence glucose tolerance, nor hepatic inflammatory or energy-sensing proteins. After the combined treatment, hepatic corticosterone was increased, glucose tolerance remained preserved, while hepatic inflammation was partially prevented despite decreased AMPK activity. CONCLUSION: High-fructose diet resulted in glucose intolerance, hepatic inflammation, decreased AMPK activity and reduced insulin sensitivity. Chronic stress alone did not exert such effects, but when applied together with high-fructose diet it could partially prevent fructose-induced inflammation, presumably due to increased hepatic glucocorticoids.

Primary signet ring cell carcinoma of the pancreas with a good response to chemotherapy: case report and literature review.

PURPOSE: Although pancreatic cancer is a common malignancy, signet ring cell carcinoma of the pancreas is a very rare histologic type with only 6 cases reported so far. We present a patient with primary signet ring cell carcinoma of the pancreas and a good response to neoadjuvant chemotherapy. CASE REPORT: A 67-year-old woman presented at a regional hospital with a 2-week history of painless progressive jaundice. Abdominal computed tomography showed a tumor in the head of the pancreas, 4.5 cm in largest diameter. Since endoscopic biopsy and biliary stenting were not available, the patient had undergone palliative choledochoduodenostomy and tru-cut needle biopsy of the lesion. Histopathology revealed primary signet ring cell carcinoma of the pancreas. The tumor was considered borderline resectable and 3-month neoadjuvant chemotherapy with gemcitabine alone was administered due to the low creatinine clearance rates. Follow-up abdominal scan demonstrated very good response to chemotherapy and significant tumor regression to 1.5 cm in largest diameter. Radical cephalic duodenopancreatectomy was performed. CONCLUSION: Significant tumor downsizing in our patient clearly demonstrates good response to neoadjuvant gemcitabine monotherapy. The optimal preoperative chemotherapy leading to tumor reduction and disease control in patients with borderline resectable and locally advanced pancreatic carcinoma is controversial, necessitating further randomized studies including combined chemoradiotherapy and multidrug combination regimens.

Reproducibility of 24-h heart rate variability in children.

BACKGROUND: Over the last decades, time domain heart rate (HR) variability analysis has been explored in different pediatric clinical settings to obtain information on the cardiac autonomic tone. However, the consistency over time of 24 h time domain HRV measurements in children is not well-known. METHODS: We investigated the reproducibility of 24 h HRV time-domain indices (1 day apart), from 39 healthy children (9.5 ± 5.3 years, 56.4% girls). The parameters analysed included: standard deviation of all the adjacent NN intervals, standard deviation of the averages of NN intervals (the intervals between normal R-peaks) in all 5-min segments, and square root of the mean of the sum of the squares of the differences between adjacent NN intervals, uncorrected and corrected for HR. Reproducibility between two 24-h ECG recordings was evaluated by intraclass correlation coefficients, standard error of measurement, coefficients of variation and Bland-Altman plots. RESULTS: For the analyzed time-domain indices, standard deviation of all the adjacent NN intervals corrected for HR showed best reproducibility with the highest intraclass correlation coefficient (0.987), the lowest coefficients of variation (5.5%) and the best level of agreement between two recordings as assessed by Bland-Altman plots. CONCLUSIONS: Our results indicate that the standard deviation of all the adjacent NN intervals corrected for the HR parameter obtained from 24-h ambulatory recordings in children is consistent and reproducible over time, thus allowing reliable identification of cardiac autonomic tone in this age group.

Ultrasound and magnetic resonance imaging in prenatal diagnosis of sacrococcygeal teratoma--case report.

INTRODUCTION: Fetal tumors are relatively rare and the early prenatal diagnosis enables the prediction of possible complications and decision for appropriate treatment. This paper deals with the role of ultrasonography and magnetic resonance imaging in the early prenatal diagnosis of sacrococcygeal teratoma. CASE REPORT: A 21-year-old primigravida was found to have a large sacrococcygeal tumor measuring 25 x 30mm, presented mainly as a solid mass, when she underwent the initial ultrasound examination on the first day of 19th week of gestation. There were no other associated anomalies. The second ultrasound examination was obtained after 6 days and revealed that the tumor had doubled its size. The prominent enlargement raised suspicion of immature sacrococcygeal teratoma and thus, fetal magnetic resonance imaging was performed in the 20th gestation week. The examination showed a crococcygeal teratoma presented as a large solid mass with small microcystic areas, the largest diameter being 60mm, completely externally positioned with no intra-pelvic extension. Rapid tumor growth posed a threat to the fetal circulation and it was the main reason when opting for the termination of pregnancy at 20 weeks of gestation. Pathohystological examination confirmed the diagnosis of immature sacrococcygeal teratoma. DISCUSSION: In the prenatal period the magnetic resonance imaging of a fetal tumor initially diagnosed by ultrasound examination is an additional part of diagnostic procedure, and it is not contraindicated during pregnancy. Magnetic resonance imaging improves the delineation of the tumor. The prompt prenatal diagnosis of sacrococcygeal teratoma, as well as the detection of possible associated anomalies, is important for the pregnancy management, prediction of possible complications and choice of appropriate treatment. CONCLUSION: Ultrasonography and magnetic resonance imaging are noninvasive, compatible and complementary diagnostic modalities in evaluation of sacrococcygeal teratoma in prenatal period.

[Comparative analysis of linear morphometric parameters of the humane mandibula obtained by direct and indirect measurement].

BACKGROUND/AIM: Reconstruction of lost, damaged or distorted mandibular bone presents a challenge from the functional side, as well as from the esthetic point of view. The aim of this study was to determinate potential differences between values of the basic linear moprhometric parameters (LMPs) obtained by direct and indirect manual measurement of the same humane mandibles, with accuracy testing of indirect measurement, which are routinely used in every-day clinical practice. The results are essential for defining of parametric model of the "standard mandible" and virtual modeling of the humane mandible in future researches as well as in clinical medicine. METHODS: A total number of 12 dry bony mandibles of human adults were studied. According to the standard anatomical landmarks, 10 standard LPMs were measured on each mandible by different manual methods: directly by a sliding caliper with nonius, and indirectly using standard software on two-dimensional (2D) reconstructions of mandibular multislice computed tomography (MSCT) scans. The values obtained by the different measuring methods were matched for the same LMPs. RESULTS: Statistically significant differences between compared LMPs values obtained by different measuring methods, appeared in the gnathio-interdental distance (Gn-IdD), as well as in the gnathio-condylar distance (Gn-CoD), bilaterally. In both parameters, significantly higher mean values (with percent of difference) were obtained by direct versus indirect measurement: Gn-IdD (21.57%; 29.2 mm vs 22.9 mm; p = 0.004); Gn-CoD left side (14.1%; 122.7 mm vs 105.4 cm; p = 0.001); Gn-CoD right side (11.87%; 124.7 mm vs 109.9 mm; p = 0.009). CONCLUSION: According to the observed inaccuracy of indirect measurement, we recommended the use of a correction factor for calculation of both Gn-IdD and Gn-CoD real vales, in defining of parametric model of the "standard mandible" based on indirect morphometry on 2D reconstructions of mandibular MSCT scans. Additional studies with larger number of specimens and quantification of anatomical variations regarding to sex, age, dentition status and ethnic origin, additionally should increase measurement accuracy and consequently reliability of future parametric model of the human mandible.