Evaluation of Marginal and Internal Adaptation of Crowns Fabricated with Three Different Zirconia CAD/CAM Materials

BACKGROUND

Marginal and internal adaptation are key factors that determine the clinical success of dental restorations.

AIM

The aim of this study is to evaluate the marginal and internal fit of crowns fabricated with three different CAD-CAM zirconia materials; two monolithic zirconia materials and one veneered zirconia copings in comparison with conventional metal-ceramic crowns.

MATERIAL AND METHODS

Ninety-six extracted molars (n = 96) were selected. Teeth were randomly divided into four groups (n = 24), and the following restorations were fabricated: Metal-ceramic crowns (Control group) (Group CG); monolithic zirconia crowns (GC initial) (Group MZ1); monolithic zirconia crowns (InCoris TZI),(Group MZ2); bilayered zirconia crowns, cores (InCoris ZI) veneered with a low-fusing glass-ceramic (IPS Emax Ceram),(Group BZ). Internal and marginal adaptations were evaluated using the silicone replica technique. A total of 20 points were recorded for every tooth under the light microscope at 20x magnifications. Results were compared using one-way analysis of variance (ANOVA) and the posthoc Tukey's test at a significance level of 0.01.

RESULTS

Marginal, marginal-internal, axial, and occlusal gaps between CG, MZ1, MZ2, and BZ crowns showed statistically significant differences (P < 0.01).

CONCLUSION

Monolithic zirconia groups showed better marginal adaptation compared with the veneered zirconia crowns.

Whole-exome sequencing reveals genetic variants in low-risk and high-risk neuroblastoma

This study aimed to investigate the genetic aberrations in neuroblastoma (NB) by comparing high and low-risk NB patients by whole-exome sequencing (WES) and to reveal the heterogeneity and association between somatic variants and clinical features. Seven NB patients with available clinical data were included in the study (4 in the low-risk group and 3 in the high-risk group). WES was performed and somatic variants associated with NB genes in the COSMIC database were selected through bioinformatics pipeline analysis. Variants were determined using the Integrative Genomics Viewer (IGV). Some gene variations were found in both groups, including variations in oncogene and tumor suppressor genes. In general, candidate gene variations were associated with chromatin remodeling complexes, the RAS pathway, cell proliferation, and DNA repair mechanism. Some variations in CSF1R, MSH6, PTPN11, SOX9, RET, TSC1, and DNMT1 genes were detected only in high-risk patients, while EP300, TET2, MYCN, PRDM1, and ARID2 gene variations were detected only in low-risk patients. When high-risk gene variants were compared with the cBioportal cancer genomic database, two common gene variants (ARID1A and NCOR2) were identified. However, when low-risk gene variants were compared with the cBioportal cancer genomic database, no common genes were found. GO/KEGG enrichment analysis was performed to find relevant biological processes and molecular pathways related to gene variants, which will help to decipher the molecular mechanisms of NB tumorigenesis and the phenotypic differences between high-risk and low-risk patients.

New insights into epigenetic regulation of resistance to PD-1/PD-L1 blockade cancer immunotherapy: mechanisms and therapeutic opportunities

Programmed cell death protein 1(PD-1) is a type of immune-inhibitory checkpoint protein, which delivers inhibitory signals to cytotoxic T cells by binding to the programmed death ligand-1 (PD-L1) displayed on the surface of cancer cells. Antibodies blocking PD-1/PD-L1 interaction have been extensively used in treatment of human malignancies and have achieved promising outcomes in recent years. However, gradual development of resistance to PD-1/PD-L1 blockade has decreased the effectiveness of this immunotherapy in cancer patients. The underlying epigenetic mechanisms need to be elucidated for application of novel strategies overcoming this immunotherapy resistance. Epigenetic aberrations contribute to cancerogenesis by promoting different hallmarks of cancer. Moreover, these alterations may lead to therapy resistance, thereby leading to poor prognosis. Recently, the epigenetic regulatory drugs have been shown to decrease the resistance to PD-1/PD-L1 inhibitors in certain cancer patients. Inhibitors of the non-coding RNAs, DNA methyltransferases, and histone deacetylases combined with PD-1/PD-L1 inhibitors have shown considerable therapeutic efficacy against carcinomas as well as blood cancers. Importantly, DNA methylation-mediated epigenetic silencing can inhibit antigen processing and presentation, which promotes cancerogenesis and aggravates resistance to PD-1/PD-L1 blockade immunotherapy. These observations altogether suggest that the combination of the epigenetic regulatory drugs with PD-1/PD-L1 inhibitors may present potential solution to the resistance caused by monotherapy of PD-1/PD-L1 immunotherapy.

Plasma Concentrations and Cancer-Associated Mutations in Cell-Free Circulating DNA of Treatment-Naive Follicular Lymphoma for Improved Non-Invasive Diagnosis and Prognosis

Follicular lymphoma (FL) is the second most frequent non-Hodgkin lymphoma accounting for 10-20% of all lymphomas in western countries. As a clinically heterogeneous cancer, FL occasionally undergoes histological transformation to more aggressive B cell lymphoma types that are associated with poor prognosis. Here we evaluated the potential of circulating cell-free DNA (cfDNA) to improve the diagnosis and prognosis of follicular lymphoma patients. Twenty well-characterized FL cases (13 symptomatic and 7 asymptomatic) were prospectively included in this study. Plasma cfDNA, formalin-fixed paraffin-embedded (FFPE) tumor tissue DNA, and patient-matched granulocyte genomic DNA samples were obtained from 20 treatment-naive FL cases. Ultra-deep targeted next-generation sequencing was performed with these DNA samples by using a custom-designed platform including exons and exon-intron boundaries of 110 FL related genes. Using a strict computational bioinformatics pipeline, we identified 91 somatic variants in 31 genes in treatment-naive FL cases. Selected variants were cross-validated by using PCR-Sanger sequencing. We observed higher concentrations of cfDNA and a higher overlap of somatic variants present both in cfDNA and tumor tissue DNA in symptomatic FL cases compared to asymptomatic ones. Variants known to be associated with FL pathogenesis such as STAT6 p.D419 or EZH2 p.Y646 were observed in patient-matched cfDNA and tumor tissue samples. Consistent with previous observations, high Ki-67 staining, elevated LDH levels, FDG PET/CT positivity were associated with poor survival. High plasma cfDNA concentrations or the presence of BCL2 mutations in cfDNA showed significant association with poor survival in treatment-naive patients. BCL2 mutation evaluations in cfDNA improved the prognostic utility of previously established variables. In addition, we observed that a FL patient who had progressive disease contained histological transformation-associated gene (i.e. B2M and BTG1) mutations only in cfDNA. Pre-treatment concentrations and genotype of plasma cfDNA may be used as a liquid biopsy to improve diagnosis, risk stratification, and prediction of histological transformation. Targeted therapies related to oncogenic mutations may be applied based on cfDNA genotyping results. However, the results of this study need to be validated in a larger cohort of FL patients as the analyses conducted in this study have an exploratory nature.

In Silico Methods for the Identification of Diagnostic and Favorable Prognostic Markers in Acute Myeloid Leukemia

Acute myeloid leukemia (AML), the most common type of acute leukemia in adults, is mainly asymptomatic at early stages and progresses/recurs rapidly and frequently. These attributes necessitate the identification of biomarkers for timely diagnosis and accurate prognosis. In this study, differential gene expression analysis was performed on large-scale transcriptomics data of AML patients versus corresponding normal tissue. Weighted gene co-expression network analysis was conducted to construct networks of co-expressed genes, and detect gene modules. Finally, hub genes were identified from selected modules by applying network-based methods. This robust and integrative bioinformatics approach revealed a set of twenty-four genes, mainly related to cell cycle and immune response, the diagnostic significance of which was subsequently compared against two independent gene expression datasets. Furthermore, based on a recent notion suggesting that molecular characteristics of a few, unusual patients with exceptionally favorable survival can provide insights for improving the outcome of individuals with more typical disease trajectories, we defined groups of long-term survivors in AML patient cohorts and compared their transcriptomes versus the general population to infer favorable prognostic signatures. These findings could have potential applications in the clinical setting, in particular, in diagnosis and prognosis of AML.

A prognostic model for melanoma patients on the basis of immune-related lncRNAs

The prognosis of melanoma patients is highly variable due to multiple factors conditioning immune response and driving metastatic progression. In this study, we have correlated the expression of immune-related lncRNAs with patient survival, developed a prognostic model, and investigated the characteristics of immune response in the diverse groups. The gene expression profiles and prognostic information of 470 melanoma patients were downloaded from TCGA database. Significantly predictive lncRNAs were identified by multivariate Cox regression analyses, and a prognostic model based on these variables was constructed to predict survival. Kaplan-Meier curves were plotted to estimate overall survival. The predictive accuracy of the model was evaluated by the area under the ROC curve (AUC). Principal component analysis was used to observe the distribution of immune-related genes. CIBERSORT and ESTIMATE were used to evaluate the composition of immune cells and the immune microenvironment. Eight immune-related lncRNAs were determined to be prognostic by multivariate COX regression analysis. The patient scores were calculated and divided into high- and low-risk groups. The model could effectively predict the prognosis in patients of different stages. The AUC of the model is 0.784, which was significantly higher than that of the other variables. There were significant differences in the distribution of immune-related genes between two groups; the immune score and immune function enrichment score were higher in the low risk group.

PRDM1 decreases sensitivity of human NK cells to IL2-induced cell expansion by directly repressing CD25 (IL2RA)

IL2 receptor signaling is crucial for human NK cell activation and gain of effector functions. The molecular mechanisms involved in termination of IL2 activation are largely unknown in human NK cells. PR/SET domain 1 was previously reported to decrease cell growth and increase apoptosis in an IL2-dependent manner in malignant NK cell lines, suggesting the possibility of down-regulation of IL2 signaling pathway gene(s) through direct transcriptional repression. Using ChIP-Seq, we identified a PRDM1 binding site on the first intron of CD25 (IL2RA), which codes for the IL2 receptor subunit regulating sensitivity to IL2 signaling, in primary NK cells activated with engineered K562 cells or IL2. Ectopic expression of PRDM1 down-regulated CD25 expression at transcript and protein levels in two PRDM1 nonexpressing NK cell lines. shRNA-mediated knockdown of CD25 in two malignant NK cell lines led to progressive depletion of NK cells in low IL2 concentrations. By contrast, ectopic CD25 expression in primary human NK cells led to progressive increase in cell number in CD25-transduced cells in low IL2 concentrations. Altogether these results reveal a pivotal role of PRDM1 in inhibition of IL2-induced NK cell expansion through direct repression of CD25 in activated human NK cells. These observations provide additional support for the role of PRDM1 in attenuation of NK cell activation and growth, with implications on neoplastic transformation or NK cell function when it is deregulated.

Indolent T-Cell Lymphoproliferative Disease of the GI Tract: Insights for Better Diagnosis, Prognosis, and Appropriate Therapy

Indolent T-cell lymphoproliferative disease of the gastrointestinal tract (indolent GI T-LPD) is a benign neoplasm of CD4⁺ or CD8⁺ T cells that form primary tumors in the GI tract. Indolent GI T-LPD has recently been provisionally recognized as a distinct entity by the 2016 revision of the WHO classification of lymphoid neoplasms. Appropriate diagnosis of these cases is challenging as they may be misdiagnosed as T cell lymphoma that has an aggressive clinical course. Consequently, aggressive therapeutic approaches were usually chosen to treat these cases with no obvious benefit for most of the patients and potential side effects. Moreover, inflammatory diseases of the GI tract with similar symptoms may lead to misdiagnosis that leads to delays in administration of proper therapeutics against these cases. Therefore, it is of utmost importance to identify prognostic genetic biomarkers at the time of diagnosis for optimal medical care of these patients. TCR clonality analyses may not be useful for distinguishing these benign neoplasms from aggressive gastrointestinal T cell lymphomas; however, molecular genetic tests may prove useful as recurrent STAT3-JAK2 fusions, which may have diagnostic, prognostic or therapeutic value, have recently been identified. However, there is still lack of comprehensive information on the genetic and epigenetic factors associated with pathogenesis of indolent GI T-LPD. In this mini-review, we focus on the so far reported literature on indolent GI T-LPD cases, and discuss future directions for better differential diagnosis, risk stratification, and therapeutic target discovery with a special focus on the genetic and epigenetic alterations.

Effects of bradykinin preconditioning in an experimental intestinal ischemia reperfusion model on rats

PURPOSE

To investigate the effects of bradykinin on reperfusion injury in an experimental intestinal ischemia reperfusion model.

METHODS

We used 32 Wistar-Albino rats. We composed 4 groups each containing 8 rats. Rats in sham group were sacrified at 100 minutes observation after laparotomy. Thirty minutes reperfusion was performed following 50 minutes ischaemia in control group after observing 20 minutes. Ischaemic preconditioning was performed in one group of the study. We performed the other study group pharmacologic preconditioning by infusional administration of 10 μg/kg/minute bradykinin intravenously. We sacrified all of the rats by taking blood samples to evaluate the lactate and lactate dehydrogenase (LDH) after resection of jejunum for detecting tissue myeloperoxidase (MPO) activity.

RESULTS

Lactate and LDH levels were significantly higher in control and study groups than the sham group (P<0.001). There is no difference between the study groups statistically. (P>0.05). The results were the same for MPO levels. Although definitive cell damage was determinated in the control group by hystopatological evaluation, the damage in the study groups observed was lower in different levels. However, there was no significant difference between the study groups statistically (P>0.05).

CONCLUSION

Either ischeamic preconditioning or pharmacologic preconditioning made by bradykinin reduced the ischemia reperfusion injury at jejunum.

Epigenetic aberrations in natural killer/T-cell lymphoma: diagnostic, prognostic and therapeutic implications

Natural killer/T-cell lymphoma (NKTCL) is an aggressive malignancy that usually presents in the upper aerodigestive tract. This malignancy shows substantial geographic variability in incidence, and is characterized by Epstein-Barr virus (EBV) infections. Epigenetic aberrations may dysregulate the expression of genes involved in different hallmarks of cancer. A growing body of evidence underscores the importance of epigenetic aberrations in the pathogenesis of NKTCL. Promoter hypermethylation is a common epigenetic mechanism for the inactivation of tumour suppressor genes. Several epigenetically silenced tumour suppressor candidates (e.g. PRDM1, BIM) were identified in this aggressive cancer using locus-specific and genome-wide promoter methylation analyses. Importantly, genes involved in epigenetic modifications were identified to be mutated (e.g. KMT2D) or methylated (e.g. TET2) in NKTCL patients, which may contribute to pathogenesis through global alterations in chromatin states. Cancer-associated microRNAs, some of which are expressed by EBV, and long noncoding RNAs have been observed to be dysregulated in NKTCL. This review focuses on studies investigating epigenetic aberrations in NKTCL to bolster our overall understanding of the role of these abnormalities in disease pathobiology. We also discuss the potential of these epigenetic aberrations to improve diagnosis and prognosis as well as reveal novel targets of therapy for NKTCL.

Genetic alterations in B cell lymphoma subtypes as potential biomarkers for noninvasive diagnosis, prognosis, therapy, and disease monitoring

Neoplastic transformation of germinal center B (GCB) cells may give rise to a variety of different B cell lymphoma subtypes, most of which show substantial heterogeneity in terms of genetic alterations and clinical features. The mutations observed in cancer-related genes in GCB cells are related to abnormalities in the immunogenetic mechanisms associated with germinal center reaction. Recent studies have rapidly identified genomic alterations in B cell lymphomas that may be useful for better subclassification, noninvasive diagnosis, and prediction of response to therapy. The WHO recognizes different lymphoma subsets classified within 2 major categories of B cell lymphoma: Hodgkin’s lymphoma (HL) and B cell non-Hodgkin’s lymphoma (NHL), each with distinct genetic aberrations, including chromosomal translocations, copy number abnormalities, or point mutations. Next-generation sequencing-based technologies have allowed cancer researchers to identify somatic mutations and gene expression signatures at a rapid pace so that novel diagnostic or prognostic biomarkers, as well as therapeutic targets, can be discovered much faster than before. Indeed, deep sequencing studies have recently revealed that lymphoma-specific somatic mutations may be detected in cell-free circulating DNA obtained from the peripheral blood of B cell lymphoma patients, suggesting the possibility of minimally invasive diagnosis, monitoring, and predicting response to therapy of B cell lymphoma patients. In this study, the current status of the recurrent genetic aberrations observed during diagnosis and/or relapse in HL and the major subtypes of B cell NHL (i.e. diffuse large B cell lymphoma, follicular lymphoma, mantle cell lymphoma, and Burkitt lymphoma) are discussed to shed light on their potential use as noninvasive diagnostic or prognostic biomarkers and to reveal their role in lymphomagenesis as a target in therapy for newly diagnosed and chemotherapy-resistant cases.

Systematic analysis of the frequently amplified 2p15-p16.1 locus reveals PAPOLG as a potential proto-oncogene in follicular and transformed follicular lymphoma

Transformed follicular lymphoma (tFL) originates from histological transformation of follicular lymphoma (FL), which is the most common indolent non-Hodgkin lymphoma. High-resolution genomic copy-number analysis previously identified frequent amplification of the 2p15-p16.1 locus in FL and tFL cases. The genes (i.e. BCL11A, PAPOLG, PUS10, and USP34) in this amplified locus have not been systematically investigated to date in terms of their role in FL pathogenesis or transformation to tFL. Here we investigated the relationship between amplification and expression of genes in 2p15-p16.1 as well as their expression after histological transformation. NCBI GEO SNP array and gene expression profile (GEP) data of tFL cases were analyzed to evaluate the relationship between amplification and mRNA expression. Moreover, transcript levels of these four genes in FL cases were compared with those of patient-matched tFL cases and normal B-cells. Amplification of the 2p15-p16.1 locus is associated with increased transcription of BCL11A and PAPOLG in tFL cases, of which the latter showed increased expression after histological transformation. Compared with the level in normal B-cells, PAPOLG was significantly overexpressed in FL cases, but expression levels of the other three genes did not show any significant difference. Altogether these results suggest that PAPOLG may be the most critical gene in terms of transformation to tFL.

Primary cardiac diffuse large B-cell lymphoma with concurrent high MYC and BCL2 expression in an immunocompetent Chinese elderly woman

Primary cardiac lymphoma is a rare type of extranodal lymphoma that involves only heart and/or pericardium. It is usually observed in immunodeficient people. However, immunocompetent patients may also suffer from this disease. Most primary cardiac lymphomas are of B-cell lineage, and they usually present as diffuse large B-cell lymphoma (DLBCL). Diffuse large B-cell lymphoma with concurrently high MYC and BCL2 expression, which is named as double-expressor lymphoma (DEL), is a rare subtype of DLBCL. Here we report a rare case of a primary cardiac DEL in an immunocompetent 65-year old Chinese woman. Echocardiography and magnetic resonance imaging revealed a mass of 6.6 cm×5.6 cm in the right atrium. No tumor formations were observed in other organs. Histopathologic examination showed that the cardiac tumor was diffuse large B-cell lymphoma, non-germinal center B-cell type by Hans algorithm. The tumor cells showed high MYC and BCL2 protein expression by immunohistochemistry, with high proliferative index.

Whole transcriptome analysis reveals dysregulated oncogenic lncRNAs in natural killer/T-cell lymphoma and establishes MIR155HG as a target of PRDM1

Natural killer/T-cell lymphoma is a rare but aggressive neoplasm with poor prognosis. Despite previous reports that showed potential tumor suppressors, such as PRDM1 or oncogenes associated with the etiology of this malignancy, the role of long non-coding RNAs in natural killer/T-cell lymphoma pathobiology has not been addressed to date. Here, we aim to identify cancer-associated dysregulated long non-coding RNAs and signaling pathways or biological processes associated with these long non-coding RNAs in natural killer/T-cell lymphoma cases and to identify the long non-coding RNAs transcriptionally regulated by PRDM1. RNA-Seq analysis revealed 166 and 66 long non-coding RNAs to be significantly overexpressed or underexpressed, respectively, in natural killer/T-cell lymphoma cases compared with resting or activated normal natural killer cells. Novel long non-coding RNAs as well as the cancer-associated ones such as SNHG5, ZFAS1, or MIR155HG were dysregulated. Interestingly, antisense transcripts of many growth-regulating genes appeared to be transcriptionally deregulated. Expression of ZFAS1, which is upregulated in natural killer/T-cell lymphoma cases, showed association with growth-regulating pathways such as stabilization of P53, regulation of apoptosis, cell cycle, or nuclear factor-kappa B signaling in normal and neoplastic natural killer cell samples. Consistent with the tumor suppressive role of PRDM1, we identified MIR155HG and TERC to be transcriptionally downregulated by PRDM1 in two PRDM1-null NK-cell lines when it is ectopically expressed. In conclusion, this is the first study that identified long non-coding RNAs whose expression is dysregulated in natural killer/T-cell lymphoma cases. These findings suggest that ZFAS1 and other dysregulated long non-coding RNAs may be involved in natural killer/T-cell lymphoma pathobiology through regulation of cancer-related genes, and loss-of-PRDM1 expression in natural killer/T-cell lymphomas may contribute to overexpression of MIR155HG; thereby promoting tumorigenesis.

The relationship of REL proto-oncogene to pathobiology and chemoresistance in follicular and transformed follicular lymphoma

Follicular lymphoma (FL) is a common type of indolent lymphoma that occasionally transforms to more aggressive B-cell lymphomas. These transformed follicular lymphomas (tFL) are often associated with chemoresistance whose mechanisms are currently unknown. REL, a proto-oncogene located on frequently amplified 2p16.1-p15 locus, promotes tumorigenesis in many cancer types through deregulation of the NF-κB pathway; however, its role in FL pathobiology or chemoresistance has not been addressed. Here, we evaluated REL gene copy number by q-PCR on FFPE FL tumor samples, and observed REL amplification in 30.4% of FL cases that was associated with weak elevation of transcript levels. PCR-Sanger analysis did not show any somatic mutation in FL tumors. In support of a marginal oncogenic role, a REL-transduced FL cell line was positively selected under limiting serum conditions. Interestingly, reanalysis of previously reported gene expression profiles revealed significant enrichment of DNA damage-induced repair and cell cycle arrest pathways in tFL tumors with high REL expression compared to those with low REL expression consistent with the critical role of c-REL in genotoxicity-induced NF-κB signaling, which was reported to lead to drug resistance. In addition to DNA damage repair genes such as ATM and BRCA1, anti-apoptotic BCL2 was significantly elevated in REL-high FL and tFL tumors. Altogether these data suggest that other genes located in amplified 2p16.1-p15 locus may have more oncogenic role in FL etiology; however, high REL expression may be useful as a predictive biomarker of response to immunochemotherapy, and inhibition of c-REL may potentially sensitize resistant FL or tFL cells to chemotherapy.

Diagnostic and Biological Significance of KIR Expression Profile Determined by RNA-Seq in Natural Killer/T-Cell Lymphoma

Natural killer/T-cell lymphoma (NKTCL) is a rare, aggressive form of non-Hodgkin lymphoma that is generally incurable at more advanced stages with systemic involvement. Clonal diagnostic markers (eg, unique T- or B-cell receptor rearrangements) are not available for NKTCLs. Killer cell immunoglobulin like receptors (KIRs) are a family of type I transmembrane glycoproteins involved in the inhibition or activation of NK cells. A restricted expression profile of KIRs has been proposed as clonal markers of NK-cell proliferations. Here we evaluated the transcription profile of all KIR family genes and C-type lectin receptor genes using RNA sequencing on NKTCL cases (n = 17) and NK-cell lines (n = 3). The expression of all KIRs tended to be markedly reduced or absent in NKTCL, except for the KIR family member killer Ig-like receptor 2DL4 (KIR2DL4; alias CD158D), which was selectively overexpressed in the majority (59%) of cases. No specific expression pattern was observed for C-type lectin receptors. KIR2DL4 is an unusual member of the KIR family that recognizes human leukocyte antigen G and mediates NK-cell activation through inducing proliferation and survival pathways such as AKT and NF-κB. Stable knockdown of KIR2DL4 in two malignant NK-cell lines with high KIR2DL4 expression significantly reduced cell growth. Selective overexpression of KIR2DL4 and down-regulation of inhibitory KIRs may contribute to NKTCL pathogenesis.

Global promoter methylation analysis reveals novel candidate tumor suppressor genes in natural killer cell lymphoma

PURPOSE

To identify tumor suppressor genes epigenetically silenced by promoter hypermethylation in extranodal natural killer cell lymphoma (NKCL).

EXPERIMENTAL DESIGN

Promoter methylation was analyzed with global and locus-specific methylation assays in NKCL cases and NK cell lines. Gene expression profiles were used to identify genes for which aberrant promoter methylation was associated with transcriptional silencing. Selected DNA methylations were validated by RRBS, pyrosequencing, or q-MSP. Decitabine treatment was performed to evaluate reactivation of methylated genes. The tumor suppressor effect of silenced genes was evaluated functionally by reintroducing them into NK cell lines.

RESULTS

We observed significant promoter hypermethylation in most NKCL samples compared with normal NK cells. Correlation of global promoter methylation with gene expression profiles identified 95 genes with strong evidence for being silenced because of promoter methylation, including BCL2L11 (BIM), DAPK1, PTPN6 (SHP1), TET2, SOCS6, and ASNS. Known tumor suppressor genes were significantly overrepresented in this set of genes. Decitabine treatment of NK cell lines was associated with reexpression of all 10 selected methylated and silenced genes. Ectopic expression of frequently silenced BIM in two BIM-nonexpressing NK cell lines led to increased apoptosis and eventual elimination of BIM-transduced cells. It also sensitized these cell lines to chemotherapy-induced apoptosis. Similarly, reintroduction of SOCS6 significantly inhibited growth in SOCS6-nonexpressing NK cell lines. NK cell lines lacking ASNS expression showed increased sensitivity to treatment with l-asparaginase. Reintroduction of ASNS reduced drug sensitivity.

CONCLUSION

Promoter region hypermethylation is frequent in NKCL, and aberrantly methylated genes are pathologically and clinically significant.

Activating mutations of STAT5B and STAT3 in lymphomas derived from γδ-T or NK cells

Lymphomas arising from NK or γδ-T cells are very aggressive diseases and little is known regarding their pathogenesis. Here we report frequent activating mutations of STAT3 and STAT5B in NK/T-cell lymphomas (n=51), γδ-T-cell lymphomas (n=43) and their cell lines (n=9) through next generation and/or Sanger sequencing. STAT5B N642H is particularly frequent in all forms of γδ-T-cell lymphomas. STAT3 and STAT5B mutations are associated with increased phosphorylated protein and a growth advantage to transduced cell lines or normal NK cells. Growth-promoting activity of the mutants can be partially inhibited by a JAK1/2 inhibitor. Molecular modelling and surface plasmon resonance measurements of the N642H mutant indicate a marked increase in binding affinity of the phosphotyrosine-Y699 with the mutant histidine. This is associated with the prolonged persistence of the mutant phosphoSTAT5B and marked increase of binding to target sites. Our findings suggest that JAK-STAT pathway inhibition may represent a therapeutic strategy.

HACE1 is a tumor suppressor gene candidate in natural killer cell neoplasms

HACE1 is an E3 ubiquitin ligase located in 6q21, the genomic region frequently deleted in natural killer (NK) cell malignancies. Here, we report HACE1 as a candidate tumor suppressor gene silenced through a combination of deletion and cytosine phosphate guanine island hypermethylation. We detected deletion of HACE1 in malignant NK cell lines (6 of 9, 67%) and primary biopsies (5 of 15, 33%) by quantitative PCR, with most of the specimen showing cytosine phosphate guanine island hypermethylation in the remaining allele, leading to low mRNA transcription. The ectopic expression of HACE1 in an HACE1-null NK cell line led to apoptosis and G2/M cell cycle arrest. Moreover, HACE1 expression was up-regulated in IL-2-activated normal NK cells and NK cells cocultured with an engineered NK cell target, K562 Clone 9.mbIL21, suggesting its role in the regulation of NK cell homeostasis. In conclusion, HACE1 is another potent tumor suppressor gene located within the 6q21 region, and loss of function of multiple tumor suppressor genes within 6q21 may be a critical determinant of NK cell lymphomagenesis.

The value of D-dimer test in the diagnosis of patients with nontraumatic acute abdomen

BACKGROUND

A patient with acute abdominal pain requires rapid evaluation. In these patients, it is very important to distinguish between surgical and nonsurgical pathology. Our aim was to compare the accuracy of the leukocyte count and D-dimer test in the diagnosis of acute abdomen.

METHODS

In this prospective study, 225 patients admitted to the emergency unit due to nontraumatic acute abdomen between June 2006 and November 2007 were evaluated. The patients were divided into two groups: Group 1 patients who needed immediate laparotomy and Group 2 patients who did not. Age, gender, leukocyte count, D-dimer level, causes of acute abdominal pain, and operative findings were investigated. P values of <0.05 were considered statistically significant.

RESULTS

There was a positive correlation between the plasma D-dimer level and leukocyte count. D-dimer acted similarly to the leukocyte count in emergency abdominal conditions. The area under the receiver operating characteristic curve was statistically higher with the D-dimer test (p<0.0001). Additionally, in patients needing immediate laparotomy, the sensitivity of the D-dimer test was 95.7% versus 74.8% for leukocyte counts.

CONCLUSION

In a patient with acute abdomen, D-dimer test may be a strong alternative or an adjuvant to the leukocyte count.

[Unusual causes of intestinal perforation and their surgical treatment]

BACKGROUND

Intestinal perforation is one of the major causes of obligatory surgical intervention. There can be many different causes of perforation. The aim of this study was to evaluate the unusual causes and the surgical treatment.

METHODS

In our clinic, we operated 675 patients due to intestinal perforation over a period of six years. Perforation due to brid, trauma, colorectal tumor, mesenteric ischemia, hernias, and iatrogenic injuries were considered as usual causes and excluded from the study. The remaining 37 patients (22 male, 15 female; mean age 53.2; range 25 to 80 years) were analyzed. For statistical analysis, Mann-Whitney U and chi-square tests were used, and p < 0.05 was considered significant.

RESULTS

A localized or generalized peritonitis was the most common symptom. Leukocytosis was found in 18 patients and free abdominal air was seen in 20 patients; bedside ultrasonographic examination was done in 17 patients. The most prevalent etiological factors were non-Hodgkin lymphoma, Crohn disease and internal herniation, respectively. Eight patients died; their time to laparotomy was significantly longer (8.7 days), and half of them had malignant small bowel tumor in perforation etiology.

CONCLUSION

Mortality and morbidity rates are high in intestinal perforations due to unusual causes. Delayed laparotomy and malignant etiology may be the main factors.

Necessity of preventive colostomy for Fournier's gangrene of the anorectal region

BACKGROUND

The aim of this study was to evaluate the necessity of preventive colostomy for Fournier's gangrene of the anorectal region.

METHODS

The medical records of 37 patients with perianal Fournier's gangrene were evaluated retrospectively. Debridement(s) alone was performed in 18 patients (Group D), while debridement(s) plus Hartmann colostomy was performed in 19 patients (Group D&HC).

RESULTS

There were no statistically significant differences between the D and D&HC groups with respect to mean age (p=0.73), sex ratio (p=1.00), diabetes mellitus (p=0.88), concomitant diseases (p=0.57), and number of debridements (p=0.75). The medical and surgical complication and mortality rates and duration of hospital and intensive care unit stays were also not significantly different between the D and D&HC groups (p>0.05). Fecal diversion was done at the initial operation in 11 patients, at second operation in 6 patients, and at third operation in 2 patients. When compared, morbidity rates were similar, but mortality rates were statistically different (p=0.031).

CONCLUSION

Fournier's gangrene remains a difficult surgical problem. Despite aggressive multidisciplinary treatment, it still has a high mortality rate. Fecal diversion in the treatment of Fournier's gangrene is controversial. If necessary, preventive colostomy should be performed during the initial debridement.

The beneficial effect of propolis on cerulein-induced experimental acute pancreatitis in rats

BACKGROUND/AIMS

Inflammatory cytokines and oxidative stress have a central role in the pathogenesis of acute pancreatitis. Propolis is a resinous hive product collected by honeybees from various plant sources and has anti-inflammatory and anti-oxidant effects. The present work aimed to investigate the therapeutic role of ethanolic extract of propolis on a cerulein-induced acute pancreatitis model in rats.

METHODS

Seventy male Wistar albino rats were used in the study. Acute edematous pancreatitis was induced by subcutaneous cerulein injection (20 microg/kg) four times at one-hour intervals. Ethanolic extract of propolis 300 mg/kg was given subcutaneously at the beginning of the procedure (ethanolic extract of propolis-1 group) or 12 h after the last cerulein injection (ethanolic extract of propolis-2 group). Serum amylase and lipase levels, white blood cell count and serum tumor necrosis factor-alpha levels were measured and pancreatic tissue was evaluated histologically.

RESULTS

In the acute pancreatitis group, serum amylase and lipase levels were found to be elevated and the histopathological evaluation of the tissue revealed massive edema and inflammation with less fatty necrosis when compared to the sham and control groups. Serum amylase and lipase levels and edema formation were significantly decreased in the ethanolic extract of propolis-treated groups (p<0.001). In the ethanolic extract of propolis-2 group, in particular, tissue edema was improved markedly (p=0.001). Tissue inflammation and fatty necrosis were decreased with ethanolic extract of propolis treatment; however, the improvement was not statistically significant.

CONCLUSIONS

Treatment with ethanolic extract of propolis improved the biochemical and histopathological findings in a rat model of experimental pancreatitis. Although our findings suggest that ethanolic extract of propolis might be considered an effective agent for the treatment of acute pancreatitis, this notion should be supported with further experimental and clinical investigations.

The effect of piracetam on brain damage and serum nitric oxide levels in dogs submitted to hemorrhagic shock

BACKGROUND

To demonstrate the effect of piracetam on changes in brain tissue and serum nitric oxide levels in dogs submitted to hemorrhagic shock.

METHODS

The subjects were randomized into four subgroups each consisting of 10 dogs. Hemorrhagic shock was induced in Group I for 1 hour and no treatment was given to this group. Blood and saline solutions were administered to Group II following 1 hour hemorrhagic shock. Blood and piracetam were given to Group III following 1 hour shock. No shock was induced and no treatment was applied to Group IV. Blood samples were obtained at the onset of the experiment and at 60, 120 and 180 minutes for nitric oxide analysis. For histopathological examination, brain tissue samples were obtained at the end of the experiment.

RESULTS

The observed improvement in blood pressure and pulse rates in Group III was more than in Group II. Nitric oxide levels were increased in Group I; however, no correlation between piracetam and nitric oxide levels was determined. It was seen that recovery in brain damage in Group III was greater than in the control group.

CONCLUSION

Piracetam, added to the treatment, may ecrease ischemic damage in hemorrhagic shock.

Survival and symbiotic effectivity of lyophilized root nodule bacteria

The study has been carried out under the greenhouse and laboratory conditions, using the lyophilization technique to determine the preserving possibilities of 3 native strain isolated from bean root nodules that been widely cultivated in Turkey and was defined as Rhizobium bacteria. The strains been developed separately in the Petri dishes with YMA (Yeast Extract Mannitol Agar) sown into lyophilization tubes containing skim milk, frozen at -85 degrees C and dehydrated at -55 degrees C with vacuum. According to the cultural counting results continued for 35 months after lyophilization, while the living cells in R11 strains and R12 strains found as 41 x 10(9) and 35.5 x 10(9) cell mL(-1), respectively, the best result was determined in the R13 strain as 51.5 x 10(9) cell mL(-1). In the greenhouse trials, the dry weight of plant's green parts, the number of nodules and total nitrogen amounts were evaluated. The tested strains were inoculated with bean varieties peculiar to themselves and the lyophilizated cultures gave similar results with the main cultures kept in tubes with YMA.

Rectal carcinoid tumor with bone marrow and osteoblastic bone metastasis: a case report

Rectal carcinoids comprise 12.6% of all carcinoid tumors and represent the third largest group of the gut carcinoids. A 64-year-old woman was diagnosed as high-grade neuroendocrine carcinoma. She had liver, bone, and bone marrow metastasis. Carcinoid syndrome was diagnosed due to diarrhea, nausea, vomiting, tachycardia, and high level of 24-hour urinary 5-hydroxyindoleacetic acid (160 mg/24 hours). No response was obtained by octreotide treatment. Rectal carcinoid tumors usually show favorable prognosis; however, poorly differentiated tumors might have unusually aggressive behavior and resistance to treatment. Bone marrow involvement might be a poor prognostic factor in carcinoid tumor as has been the case in many other tumors.

[The effects of rapid and slow infusion of fluid on coagulation factors in hemorrhagic shock: an experimental dogs model]

BACKGROUND

The diagnosis of hemorrhagic shock in a patient with tachycardia and hypotension is generally straightforward. The difficulty lies in the selection of optimal approach for the patient. In this study on a canine model of deep hemorrhagic shock induced by bleeding, we used various amounts of fluid infusion to determine the most appropriate amount of fluid resuscitation.

METHODS

The study included 30 mongrel dogs. Mongrel dogs were randomized to three equal groups of 10. The control group received no treatment. The rapid infusion group received 60 mL/kg of lactated Ringer's solution in half an hour whereas the third group received 30 mL/kg during the same time period.

RESULTS

The lactate decreased in the two treatment groups. The platelet and fibrinogen levels did not vary in the slow infusion group but decreased markedly in the rapid infusion group.

CONCLUSION

In conclusion, fluid resuscitation should not be unnecessarily aggressive. The coagulation parameters are diluted in proportion with the amount of fluid given. Blood lactate level can be used as a guiding marker in evaluation of treatment effectiveness of hemorrhagic shock patients.

Large Animal-Related Abdominal Injuries

BACKGROUND

This study investigated injuries to the abdominal area of the body caused by large animals, as well as the management of this problem.

METHODS

All the patients with large animal-related abdominal injuries over a 10-year period were identified retrospectively through the general surgery registrations.

RESULTS

Overall, 113 patients were hospitalized after large animal encounters during the 10-year study period, 33 (30%) of which had large animal-related abdominal injuries. These patients comprised 10 women (30%) and 23 men (70%) with a mean age of 56 +/- 14 years. Of the 33 patients, 31 (93.9%) sustained blunt injuries and 2 (6.1%) experienced penetrating abdominal trauma. The mean Injury Severity Score was 12.7 +/- 4.0, and the mean Acute Physiology and Chronic Health Evaluation II (APACHE II) score was 10.6 +/- 3.2. The mean intensive care unit stay was 0.8 +/- 2.2 days, and the total hospital length of stay was 7.3 +/- 5.6 days. Whereas 12 patients (36.4%) were managed nonoperatively, 21 patients (63.6%) required surgery. Laparotomy showed injuries to the jejunum in three patients (9.1%), to the ileum in 13 patients (39.4%), to the ileal mesenterium in 1 patient (3%), to the liver in 4 patients (12.1%), and to the spleen in 2 patients (6.1%). One patient died of myocardial infarction on the second day after admission.

CONCLUSIONS

Large animal-related injuries to the abdominal area can be serious. Immediate transportation and early diagnosis of abdominal insults are important because of the frequencies of small bowel and mesenteric injuries, which are difficult to diagnose using currently available diagnostic tools.