Borderline Resectable Pancreatic Cancer: Challenges for Clinical Management.

Background: Pancreatic ductal adenocarcinoma (PDAC) remains a significant worldwide health problem with a poor prognosis. A borderline resectable pancreatic ductal adenocarcinoma (BR-PDAC) is a tumor with limited vascular involvement that is technically resectable but with a high risk of positive margins (R1 resection). Objective: To identify the current challenges that exist in the management of BR-PDAC. Methods: A review of the literature was conducted to identify articles discussing the definitions and management of BR-PDAC. Key Findings: Several anatomic definitions of BR-PDAC exist, and there is significant heterogeneity in their utilization across published trials. To improve the odds of a margin negative (R0) resection, a neoadjuvant treatment approach involving chemotherapy with or without radiation is currently preferred. While supporting the efficacy of a neoadjuvant approach in BR-PDAC, the largest published randomized trials have utilized older gemcitabine-based regimens. Recently published Phase II evidence and meta-analyses have supported the use of modern multi-agent regimens such as FOLFIRINOX. The utility of adding radiation to a chemotherapy backbone remains in question. Due to remnant fibrosis and edema following neoadjuvant therapy, accurately selecting patients for resection based on a restaging CT scan is challenging. Furthermore, the role of adjuvant therapy in BR-PDAC patients receiving neoadjuvant therapy needs to be defined. Conclusion: Though progress has been made, the optimal management of BR-PDAC is uncertain. Phase III trials utilizing modern chemotherapeutic regimens are needed to establish a standard of care.

Dravet Syndrome in Lebanon: First Report on Cases with SCN1A Mutations.

Dravet syndrome, also known as severe myoclonic epilepsy in infancy, is a rare disease characterized by the appearance of different types of seizures in a healthy baby, triggered by various factors and stressful events. We report 8 Lebanese cases referred for molecular analysis of the SCN1A gene. Results were positive in 7 cases and revealed de novo variants at the heterozygous state in different exons of the gene for all except one, where the variant was intronic. Four variants were novel. Confirmation of Dravet syndrome is important for a better follow-up and treatment, preventing the occurrence of status epilepticus and severe neurological deterioration.

The added value of WES reanalysis in the field of genetic diagnosis: lessons learned from 200 exomes in the Lebanese population.

BACKGROUND: The past few decades have witnessed a tremendous development in the field of genetics. The implementation of next generation sequencing (NGS) technologies revolutionized the field of molecular biology and made the genetic information accessible at a large scale. However, connecting a rare genetic variation to a complex phenotype remains challenging. Indeed, identifying the cause of a genetic disease requires a multidisciplinary approach, starting with the establishment of a clear phenotype with a detailed family history and ending, in some cases, with functional assays that are crucial for the validation of the pathogenicity of a mutation. METHODS: Two hundred Lebanese patients, presenting a wide spectrum of genetic disorders (neurodevelopmental, neuromuscular or metabolic disorders, etc.), sporadic or inherited, dominant or recessive, were referred, over the last three and a half years, to the Medical Genetics Unit (UGM) of Saint Joseph University (USJ). In order to identify the genetic basis of these diseases, Whole Exome Sequencing (WES), followed by a targeted analysis, was performed for each case. In order to improve the genetic diagnostic yield, WES data, generated during the first 2 years of this study, were reanalyzed for all patients who were left undiagnosed at the genetic level. Reanalysis was based on updated bioinformatics tools and novel gene discoveries. RESULTS: Our initial analysis allowed us to identify the specific genetic mutation causing the disease in 49.5% of the cases, in line with other international studies. Repeated WES analysis enabled us to increase the diagnostics yield to 56%. CONCLUSION: The present article reports the detailed results of both analysis and pinpoints the contribution of WES data reanalysis to an efficient genetic diagnosis. Lessons learned from WES reanalysis and interpretation are also shared.

Low-dose radiobiology program at Canadian nuclear laboratories: past, present, and future.

Health risks associated with the exposure of humans to low-dose ionizing radiation are currently estimated using the Linear-No-Threshold model. Over the last few decades, however, this model has been widely criticized for inconsistency with a large body of experimental evidence. Substantial efforts have been made to delineate biological mechanisms and health-related outcomes of low-dose radiation. These include a large DOE-funded Low Dose program operated in the 2000s, as well as the EU funded programs, previously NOTE and DOREMI and currently MELODI. Although not as widely known, the Atomic Energy of Canada Limited (AECL) in Chalk River, operated a low-dose radiobiology program since as early as 1948. The Canadian Nuclear Laboratories (CNL), the successor to AECL since 2015, has expanded this program into new areas making it the world's most robust, centrally coordinated and long-lived research efforts to delineate the biological effects of low-dose radiation. The purpose of this review is to provide a high-level overview of the low-dose radiobiology program maintained at CNL while capturing the historical perspectives. Past studies carried out at CNL have substantially influenced the area of low-dose radiobiology, exemplified by highly cited papers showing delays in spontaneous tumorigenesis in low-dose irradiated mice. The current low-dose research program at CNL is not only addressing a wide range of mechanistic questions about the biological effects of low doses - from genetic to epigenetic to immunological questions - but also moving toward novel areas, such as the dosimetry and health consequences of space radiation and the use of low-dose radiation in cancer therapy and regenerative medicine.

Contribution of next generation sequencing in pediatric practice in Lebanon. A Study on 213 cases.

BACKGROUND: According to the Catalogue of Transmission Genetics in Arabs, less than half of diseases reported in Lebanese patients are mapped. In the recent years, Next Generation Sequencing (NGS) techniques have significantly improved clinical diagnosis, compared to traditional sequencing methods. METHODS: A total of 213 analyses by NGS (167 by whole exome sequencing (WES) and 46 by multigene panels tests) were performed on pediatric patients across different regions of Lebanon over a period of two years (December 2015-December 2017). RESULTS: Neurological disorders were the most frequent referral demand for both WES and gene panels (122/213). Pathogenic, likely pathogenic, or variants of unknown significance were identified in 69.5% of the WES and panel patients combined. Over half of the patients with such variants had an autosomal recessive disorder. A definite molecular diagnosis (pathogenic or likely pathogenic variants) was achieved in 34.1% and 47.8% of the patients studied by WES and the multigene panels, respectively. Thirty-three novel variants were found in the cases that were molecularly solved; 26 of these being identified by WES and seven by the multigene panels. In three consanguineous families, autosomal recessive inheritance of genes previously reported as showing dominant inheritance patterns were found. Biallelism was found in six cases, digenism in four cases, and one case was trigenic. CONCLUSION: Our study thus suggests that NGS tools are valuable for an improved clinical diagnosis, and highlights that the increased adoption of such techniques will significantly further improve our understanding of the genetic basis of inherited diseases in Lebanon.

Atypical pyridoxine dependent epilepsy resulting from a new homozygous missense mutation, in ALDH7A1.

Pyridoxine dependent epilepsy (PDE) is a rare autosomal recessive neurometabolic disorder. In the classical form, seizures are observed within the first month of life, while in the atypical form seizures appear later in life, sometimes as late as at the age of 3 years of life. Both types are unresponsive to conventional anticonvulsant therapy, but can be controlled with pyridoxine monotherapy. Mutations in the ALDH7A1 gene, encoding α-aminoadipic semialdehyde dehydrogenase have been reported to cause this disease in most patients. Here, we report on a boy with developmental delay, dysmorphic facial features, and uncontrolled episodes of seizures that appeared at the age of 18 months. By whole exome sequencing (WES) a homozygous missense mutation in ALDH7A1 (NM_001182: c.239T > G, p.V80G) was found. We discuss the importance of WES in such atypical cases.

Phenotype Determines Nanoparticle Uptake by Human Macrophages from Liver and Blood.

A significant challenge to delivering therapeutic doses of nanoparticles to targeted disease sites is the fact that most nanoparticles become trapped in the liver. Liver-resident macrophages, or Kupffer cells, are key cells in the hepatic sequestration of nanoparticles. However, the precise role that the macrophage phenotype plays in nanoparticle uptake is unknown. Here, we show that the human macrophage phenotype modulates hard nanoparticle uptake. Using gold nanoparticles, we examined uptake by human monocyte-derived macrophages that had been driven to a "regulatory" M2 phenotype or an "inflammatory" M1 phenotype and found that M2-type macrophages preferentially take up nanoparticles, with a clear hierarchy among the subtypes (M2c > M2 > M2a > M2b > M1). We also found that stimuli such as LPS/IFN-γ rather than with more "regulatory" stimuli such as TGF-ß/IL-10 reduce per cell macrophage nanoparticle uptake by an average of 40%. Primary human Kupffer cells were found to display heterogeneous expression of M1 and M2 markers, and Kupffer cells expressing higher levels of M2 markers (CD163) take up significantly more nanoparticles than Kupffer cells expressing lower levels of surface CD163. Our results demonstrate that hepatic inflammatory microenvironments should be considered when studying liver sequestration of nanoparticles, and that modifying the hepatic microenvironment might offer a tool for enhancing or decreasing this sequestration. Our findings also suggest that models examining the nanoparticle/macrophage interaction should include studies with primary tissue macrophages.

HCV Specific IL-21 Producing T Cells but Not IL-17A Producing T Cells Are Associated with HCV Viral Control in HIV/HCV Coinfection.

BACKGROUND: Decreased hepatitis C virus (HCV) clearance, faster cirrhosis progression and higher HCV RNA levels are associated with Human Immunodeficiency virus (HIV) coinfection. The CD4+ T helper cytokines interleukin (IL)-21 and IL-17A are associated with virus control and inflammation, respectively, both important in HCV and HIV disease progression. Here, we examined how antigen-specific production of these cytokines during HCV mono and HIV/HCV coinfection was associated with HCV virus control. METHODS: We measured HCV-specific IL-21 and IL-17A production by transwell cytokine secretion assay in PBMCs from monoinfected and coinfected individuals. Viral control was determined by plasma HCV RNA levels. RESULTS: In acutely infected individuals, those able to establish transient/complete HCV viral control tended to have stronger HCV-specific IL-21-production than non-controllers. HCV-specific IL-21 production also correlated with HCV viral decline in acute infection. Significantly stronger HCV-specific IL-21 production was detected in HAART-treated coinfected individuals. HCV-specific IL-17A production was not associated with lower plasma HCV RNA levels in acute or chronic HCV infection and responses were stronger in HIV coinfection. HCV-specific IL-21/ IL-17A responses did not correlate with microbial translocation or fibrosis. Exogenous IL-21 treatment of HCV-specific CD8+ T cells from monoinfected individuals enhanced their function although CD8+ T cells from coinfected individuals were somewhat refractory to the effects of IL-21. CONCLUSIONS: These data show that HCV-specific IL-21 and IL-17A-producing T cells are induced in HIV/HCV coinfection. In early HIV/HCV coinfection, IL-21 may contribute to viral control, and may represent a novel tool to enhance acute HCV clearance in HIV/HCV coinfected individuals.

10q26.1 Microdeletion: Redefining the critical regions for microcephaly and genital anomalies.

Distal 10q deletion syndrome is a well-characterized chromosomal disorder consisting of neurodevelopmental impairment, facial dysmorphism, cardiac malformations, genital and urinary tract defects, as well as digital anomalies. Patients with interstitial deletions involving band 10q26.1 present a phenotype similar to the ones with the distal 10q deletion syndrome, which led to the definition of a causal 600 kb smallest region of overlap (SRO). In this report, we describe a male patient with an interstitial 4.5 Mb deletion involving exclusively the 10q26.1 segment. He had growth and psychomotor retardation, microcephaly, flat feet, micropenis, and cryptorchidism. The patient's deleted region does not overlap the 10q SRO. We reviewed the clinical phenotype of patients with similar deletions and suggest the presence of two new SROs, one associated with microcephaly, growth and psychomotor retardation, and the other associated to genital anomalies. Interestingly, we narrowed those regions to segments encompassing five and two genes, respectively. FGFR2, NSMCE4A, and ATE1 were suggested as candidates for facial dysmorphism, growth cessation, and heart defects, respectively. WDR11 was linked to idiopathic hypogonadotropic hypogonadism and Kallmann syndrome. Its haploinsufficiency could play a crucial role in the genital anomalies of these patients.

Evidence that homozygous PTPRD gene microdeletion causes trigonocephaly, hearing loss, and intellectual disability.

BACKGROUND: The premature fusion of metopic sutures results in the clinical phenotype of trigonocephaly. An association of this characteristic with the monosomy 9p syndrome is well established and the receptor-type protein tyrosine phosphatase gene (PTPRD), located in the 9p24.1p23 region and encoding a major component of the excitatory and inhibitory synaptic organization, is considered as a good candidate to be responsible for this form of craniosynostosis. Moreover PTPRD is known to recruit multiple postsynaptic partners such as IL1RAPL1 which gene alterations lead to non syndromic intellectual disability (ID). RESULTS: We describe a 30 month old boy with severe intellectual disability, trigonocephaly and dysmorphic facial features such as a midface hypoplasia, a flat nose, a depressed nasal bridge, hypertelorism, a long philtrum and a drooping mouth. Microarray chromosomal analysis revealed the presence of a homozygous deletion involving the PTPRD gene, located on chromosome 9p22.3. Reverse Transcription PCR (RT-PCR) amplifications all along the gene failed to amplify the patient's cDNA in fibroblasts, indicating the presence of two null PTPRD alleles. Synaptic PTPRD interacts with IL1RAPL1 which defects have been associated with intellectual disability (ID) and autism spectrum disorder. The absence of the PTPRD transcript leads to a decrease in the expression of IL1RAPL1. These results suggest the direct involvement of PTPRD in ID, which is consistent with the PTPRD -/- mice phenotype. Deletions of PTPRD have been previously suggested as a cause of trigonocephaly in patients with monosomy 9p and genome-wide association study suggested variations in PTPRD are associated with hearing loss. CONCLUSIONS: The deletion identified in the reported patient supports previous hypotheses on its function in ID and hearing loss. However, its involvement in the occurrence of metopic synostosis is still to be discussed as more investigation of patients with the 9p monosomy syndrome is required.

Contribution of copy number variants (CNVs) to congenital, unexplained intellectual and developmental disabilities in Lebanese patients.

BACKGROUND: Chromosomal microarray analysis (CMA) is currently the most widely adopted clinical test for patients with unexplained intellectual disability (ID), developmental delay (DD), and congenital anomalies. Its use has revealed the capacity to detect copy number variants (CNVs), as well as regions of homozygosity, that, based on their distribution on chromosomes, indicate uniparental disomy or parental consanguinity that is suggestive of an increased probability of recessive disease. RESULTS: We screened 149 Lebanese probands with ID/DD and 99 healthy controls using the Affymetrix Cyto 2.7 M and SNP6.0 arrays. We report all identified CNVs, which we divided into groups. Pathogenic CNVs were identified in 12.1% of the patients. We review the genotype/phenotype correlation in a patient with a 1q44 microdeletion and refine the minimal critical regions responsible for the 10q26 and 16q monosomy syndromes. Several likely causative CNVs were also detected, including new homozygous microdeletions (9p23p24.1, 10q25.2, and 8p23.1) in 3 patients born to consanguineous parents, involving potential candidate genes. However, the clinical interpretation of several other CNVs remains uncertain, including a microdeletion affecting ATRNL1. This CNV of unknown significance was inherited from the patient's unaffected-mother; therefore, additional ethnically matched controls must be screened to obtain enough evidence for classification of this CNV. CONCLUSION: This study has provided supporting evidence that whole-genome analysis is a powerful method for uncovering chromosomal imbalances, regardless of consanguinity in the parents of patients and despite the challenge presented by analyzing some CNVs.

Consequences of cold-ischemia time on primary nonfunction and patient and graft survival in liver transplantation: a meta-analysis.

INTRODUCTION: The ability to preserve organs prior to transplant is essential to the organ allocation process. OBJECTIVE: The purpose of this study is to describe the functional relationship between cold-ischemia time (CIT) and primary nonfunction (PNF), patient and graft survival in liver transplant. METHODS: To identify relevant articles Medline, EMBASE and the Cochrane database, including the non-English literature identified in these databases, was searched from 1966 to April 2008. Two independent reviewers screened and extracted the data. CIT was analyzed both as a continuous variable and stratified by clinically relevant intervals. Nondichotomous variables were weighted by sample size. Percent variables were weighted by the inverse of the binomial variance. RESULTS: Twenty-six studies met criteria. Functionally, PNF% = -6.678281+0.9134701*CIT Mean+0.1250879*(CIT Mean-9.89535)2-0.0067663*(CIT Mean-9.89535)3, r2 = .625, , p<.0001. Mean patient survival: 93% (1 month), 88% (3 months), 83% (6 months) and 83% (12 months). Mean graft survival: 85.9% (1 month), 80.5% (3 months), 78.1% (6 months) and 76.8% (12 months). Maximum patient and graft survival occurred with CITs between 7.5-12.5 hrs at each survival interval. PNF was also significantly correlated with ICU time, % first time grafts and % immunologic mismatches. CONCLUSION: The results of this work imply that CIT may be the most important pre-transplant information needed in the decision to accept an organ.