Identification of two new mutations in the GPR98 and the PDE6B genes segregating in a Tunisian family

Autosomal recessive retinitis pigmentosa (ARRP) is a genetically heterogeneous disorder. ARRP could be associated with extraocular manifestations that define specific syndromes such as Usher syndrome (USH) characterized by retinal degeneration and congenital hearing loss (HL). The USH type II (USH2) associates RP and mild-to-moderate HL with preserved vestibular function. At least three genes USH2A, the very large G-protein-coupled receptor, GPR98, and DFNB31 are responsible for USH2 syndrome. Here, we report on the segregation of non-syndromic ARRP and USH2 syndrome in a consanguineous Tunisian family, which was previously used to define USH2B locus. With regard to the co-occurrence of these two different pathologies, clinical and genetic reanalysis of the extended family showed (i) phenotypic heterogeneity within USH2 patients and (ii) excluded linkage to USH2B locus. Indeed, linkage analysis disclosed the cosegregation of the USH2 phenotype with the USH2C locus markers, D5S428 and D5S618, whereas the ARRP perfectly segregates with PDE6B flanking markers D4S3360 and D4S2930. Molecular analysis revealed two new missense mutations, p.Y6044C and p.W807R, occurring in GPR98 and PDE6B genes, respectively. In conclusion, our results show that the USH2B locus at chromosome 3p23-24.2 does not exist, and we therefore withdraw this locus designation. The combination of molecular findings for GPR98 and PDE6B genes enable us to explain the phenotypic heterogeneity and particularly the severe ocular affection first observed in one USH2 patient. This report presents an illustration of how consanguinity could increase familial clustering of multiple hereditary diseases within the same family.     

On Applications of a new method for computing optimal non-linear feedback controls

A new method of computing optimal non-linear feedbacks is used for regulating the angular momentum of spacecraft using both reaction jets and flywheels. It is shown that the optimal feedback law satisfies a system of first-order, quasi-linear, partial differential equations. The integration of these equations by the method of characteristics gives the non-linear feedback control. This control reduces the angular velocities of the space vehicle to zero by minimizing the fuel consumption. The optimal regulation, under reaction jet control alone and with the flywheels at fixed angular velocities, is considered. The special case where these velocities are zero leads readily to the known analytical solution of the feedback law, which is linear in the state although the dynamics is non-linear.     

A subpopulation of human B lymphocytes can express a functional Tissue Factor in response to phorbol myristate acetate

Tissue Factor (TF,CD142) is a transmembrane glycoprotein that belongs to the cytokine receptor superfamily. This multifunctional protein is constitutively present in most tissues. Among circulating blood cells, TF expression is known to be restricted to monocytes which do not constitutively produce TF but express TF in response to various stimuli. Here, we report that highly purified B lymphocytes can support a procoagulant activity (PCA) in response to phorbol myristate acetate (PMA). Using flow cytometry (FCM), we observed that a subpopulation of B lymphocytes (CD19+) can express TF and anionic phospholipids in response to PMA. TF protein was identified and characterized by immunofluorescence, immunocytochemistry and electronic microscopy. Using RT-PCR, we identified the presence of TF mRNA in response to PMA. In conclusion, B lymphocytes are a potential source of functional TF in human.     

Relationship of “new” vitamin K-dependent protein C and “old” autoprothrombin II-A

Vitamin K-dependent Protein C recently isolated by Stenflo ($\text{J. Biol. Chem.}$ 251, 355, 1976) was found to be related to autoprothrombin II-A by comparing amino acid analysis, molecular weight, immunochemical properties, and inhibitory activity in blood coagulation. Our purified Protein C converted to autoprothrombin II-A with purified thrombin in association with loss of a small peptide(s). Protein C or autoprothrombin II-A served as cofactors for epinephrine induced platelet aggregation in platelet rich plasma taken from dogs heavily dosed with warfarin. It is suggested that the designation Factor XIV be assigned to Protein C and Factor XIVa to autoprothrombin II-A with the following meaning:

$\text{Factor XIV}\text{Thrombin}\text{Factor XIVa}$

     

Toxicity assessment of Diclofenac and its biodegradation metabolites toward mice

Biodegradation of the anti-inflammatory drug Diclofenac (DCF) was studied using Enterobacter cloacae (D16) isolated from household compost. This isolate was able to eliminate 67.57% of DCF as sole carbon source after 48 h of incubation. Parallel to its disappearance, five metabolites were observed in microbial active samples which were suspected to be the DCF metabolites. GCMS showed a very similar spectrum of these metabolites with the MS spectrum of the parent compound. DCF Toxicity at different concentrations (toxic dose, therapeutic dose, and low dose) and its metabolites toxicity toward mice liver cells were evaluated. At toxic and therapeutic doses DCF had a negative effect on the oxidative stress parameters represented by a decrease in Reduced Glutathione reserve, lipid peroxidation and a disturbance of the liver detoxification enzymes (superoxide dismutase, Catalase, and glutathione S-transferase). In contrast, no effect was observed after treatment of animals with low dose and DCF biotransformation products.     

Primary true enterolithiasis: A rare cause of acute small bowel obstruction

Enterolithiasis is an uncommon medical condition. It''s defined by the formation of gastrointestinal concretion in the setting of intestinal stasis. Enteroliths are typically incidentally discovered during imaging and are a rare cause of acute small bowel obstruction. We report the case of acute small bowel obstruction, secondary to primary true enterolithiasis, in a 73-year-old male, with unremarkable medical history. He presented with clinical features in keeping with acute small bowel obstruction, for 2 days. An abdominal contrast-enhanced CT scan suggested a small bowel obstruction caused by a 32mm diameter enterolith located in the terminal ileum. The surgical management was successful and consisted of the removal of the enterolith after enterotomy.     

NOD2/CARD15 gene mutations in North Algerian patients with inflammatory bowel disease

AIM: To analyse allelic frequency of NOD2 gene variantsand to assess their correlation with inflammatory bowel disease(IBD) in Algeria.METHODS: We studied 132 unrelated patients diagnosed with IBD, 86 with Crohn's disease(CD) and 46 with ulcerative colitis(UC). Data was prospectively collected between January 2011 and December 2013. The demographic and clinical characteristics were recorded for all the patients. A group of 114 healthy unrelated individuals were selected as controls. All groups studied originated from different regions of North Algeria and confirmed the Algerian origin of their parents and grandparents. Informed and written consent was obtained from each of the participants. All individuals were genotyped for the three CDassociated NOD2 variants(p.Arg702 Trp, p.Gly908 Arg and p.Leu1007 fsins C mutations) using the polymerase chain reaction-restriction fragment length polymorphism method. Allele and genotype frequencies in patients and control subjects were compared by χ2 test and Fisher's exact test where appropriate. Odds ratios(OR) and 95% confidence intervals(95%CI) were also estimated. Association analyses were performed to study the influence of these variants on IBD and on clinical phenotypes.RESULTS: The p.Arg702 Trp mutation showed the highest frequency in CD patients(8%) compared to UC patients(2%)(P = 0.09, OR = 3.67, 95%CI: 0.48-4.87) and controls(5%)(P = 0.4, OR = 1.47, 95%CI: 0.65-3.31). In CD patients allelic frequencies of p.Gly908 Arg and p.Leu1007 fsins C variants compared to HC were 3% vs 2%(P = 0.5, OR = 1.67, 95%CI: 0.44-6.34); 2% vs 1%(P = 0.4 OR = 2.69 95%CI: 0.48-14.87 respectively). In UC patients, allelic frequencies of p.Gly908 Arg and p.Leu1007 fsins C variants compared to HC were 1% vs 2%(P = 1, OR = 1.62, 95%CI: 0.17-4.74) and 2% vs 1%(P = 0.32, OR = 0.39, 95%CI: 0.05-2.87). The total frequency of the mutated NOD2 chromosomes was higher in CD(13%), than in HC(8%) and UC(5%). In addition, NOD2 variants were linked to a particular clinical sub-phenotype in CD in this Algerian cohort. As expected, the three NOD2 variants showed a significant association with CD but did not reach statistical significance, despite the fact that the allele frequency of NOD2 variants was in the range found in most of the European populations. This might be due to the non-exposure of the NOD2 carriers to environmental factors, required for the expression of the disease.CONCLUSION: Further analyses are necessary to study genetic and environmental factors in IBD in the Algerian population, using larger patient groups.     

Metabolomic profile of cancer stem cell‐derived exosomes from patients with malignant melanoma

Malignant melanoma (MM) is the most aggressive and life‐threatening form of skin cancer. It is characterized by an extraordinary metastasis capacity and chemotherapy resistance, mainly due to melanoma cancer stem cells (CSCs). To date, there are no suitable clinical diagnostic, prognostic or predictive biomarkers for this neoplasia. Therefore, there is an urgent need for new MM biomarkers that enable early diagnosis and effective disease monitoring. Exosomes represent a novel source of biomarkers since they can be easily isolated from different body fluids. In this work, a primary patient‐derived MM cell line enriched in CSCs was characterized by assessing the expression of specific markers and their stem‐like properties. Exosomes derived from CSCs and serums from patients with MM were characterized, and their metabolomic profile was analysed by high‐resolution mass spectrometry (HRMS) following an untargeted approach and applying univariate and multivariate statistical analyses. The aim of this study was to search potential biomarkers for the diagnosis of this disease. Our results showed significant metabolomic differences in exosomes derived from MM CSCs compared with those from differentiated tumour cells and also in serum‐derived exosomes from patients with MM compared to those from healthy controls. Interestingly, we identified similarities between structural lipids differentially expressed in CSC‐derived exosomes and those derived from patients with MM such as the glycerophosphocholine PC 16:0/0:0. To our knowledge, this is the first metabolomic‐based study aimed at characterizing exosomes derived from melanoma CSCs and patients'' serum in order to identify potential biomarkers for MM diagnosis. We conclude that metabolomic characterization of CSC‐derived exosomes sets an open door to the discovery of clinically useful biomarkers in this neoplasia.

Abbreviations

CSCs

cancer stem cells

EVs

extracellular vesicles

HCs

healthy controls

HPLC

high‐performance liquid chromatography

HRMS

high‐resolution mass spectrometry

MM

malignant melanoma

MMPs

malignant melanoma patients

PCA

principal component analysis

PLS‐DA

partial least squares discriminant analysis

Q‐TOF‐MS

quadrupole time‐of‐flight mass spectrometer

ROC

receiver operating characteristic curve

TIC

total ion chromatograms

TME

tumour microenvironment

VIP

variable importance in projection