Expression of Calretinin in the Cecal Muscularis Interna: Observation and Hypothetical Relevance to Appendicitis.

BACKGROUND: The unexpected observation of calretinin immunoreactivity in smooth muscle cells in the muscularis propria of the cecum led to a more detailed examination of calretinin expression and its possible relationship to propulsive contractile activity around the vermiform appendix. METHODS: Immunohistochemistry and RNA in situ hybridization were performed to analyze calretinin expression in intestinal samples from 33 patients at ages ranging from mid-gestation fetuses to adults, as well as in some potentially relevant animal models. Dual immunolabeling was done to compare calretinin localization with markers of smooth muscle and interstitial cells of Cajal. RESULTS: Calretinin expression was observed consistently in the innermost smooth muscle layers of the muscularis interna in the human cecum, appendiceal base, and proximal ascending colon, but not elsewhere in the intestinal tract. Calretinin-positive smooth muscle cells did not co-express markers located in adjacent interstitial cells of Cajal. Muscular calretinin immunoreactivity was not detected in the ceca of mice or macaques, species which lack appendices, nor in the rabbit cecum or appendix. CONCLUSIONS: Localized expression of calretinin in cecal smooth muscle cells may reduce the likelihood of retrograde, calcium-mediated propulsive contractions from the proximal colon and suppress pro-inflammatory fecal stasis in the appendix.

Perturbed development of calb2b expressing dI6 interneurons and motor neurons underlies locomotor defects observed in calretinin knock-down zebrafish larvae.

Calcium binding proteins are essential for neural development and cellular activity. Calretinin, encoded by calb2a and calb2b, plays a role during early zebrafish development and has been proposed as a marker for distinct neuronal populations within the locomotor network. We generated a calb2b:hs:eGFP transgenic reporter line to characterize calretinin expressing cells in the developing spinal cord and describe morphological and behavioral defects in calretinin knock-down larvae. eGFP was detected in primary and secondary motor neurons, as well as in dI6 and V0v interneurons. Knock-down of calretinin lead to disturbed development of motor neurons and dI6 interneurons, revealing a crucial role during early development of the locomotor network. Primary motor neurons showed delayed axon outgrowth and the distinct inhibitory CoLo neurons, originating from the dI6 lineage, were absent. These observations explain the locomotor defects we observed in calretinin knock-down animals where the velocity, acceleration and coordination were affected during escapes. Altogether, our analysis suggests an essential role for calretinin during the development of the circuits regulating escape responses and fast movements within the locomotor network.

Quantitative Spatial Analysis of Neuroligin-3 mRNA Expression in the Enteric Nervous System Reveals a Potential Role in Neuronal-Glial Synapses and Reduced Expression in Nlgn3R451C Mice.

Mutations in the Neuroligin-3 (Nlgn3) gene are implicated in autism spectrum disorder (ASD) and gastrointestinal (GI) dysfunction, but cellular Nlgn3 expression in the enteric nervous system remains to be characterised. We combined RNAScope in situ hybridization and immunofluorescence to measure Nlgn3 mRNA expression in cholinergic and VIP-expressing submucosal neurons, nitrergic and calretinin-containing myenteric neurons and glial cells in both WT and Nlgn3R451C mutant mice. We measured Nlgn3 mRNA neuronal and glial expression via quantitative three-dimensional image analysis. To validate dual RNAScope/immunofluorescence data, we interrogated available single-cell RNA sequencing (scRNASeq) data to assess for Nlgn3, Nlgn1, Nlgn2 and their binding partners, Nrxn1-3, MGDA1 and MGDA2, in enteric neural subsets. Most submucosal and myenteric neurons expressed Nlgn3 mRNA. In contrast to other Nlgns and binding partners, Nlgn3 was strongly expressed in enteric glia, suggesting a role for neuroligin-3 in mediating enteric neuron-glia interactions. The autism-associated R451C mutation reduces Nlgn3 mRNA expression in cholinergic but not in VIPergic submucosal neurons. In the myenteric plexus, Nlgn3 mRNA levels are reduced in calretinin, nNOS-labelled neurons and S100 ß -labelled glia. We provide a comprehensive cellular profile for neuroligin-3 expression in ileal neuronal subpopulations of mice expressing the R451C autism-associated mutation in Nlgn3, which may contribute to the understanding of the pathophysiology of GI dysfunction in ASD.

Rabies virus infection is associated with variations in calbindin D-28K and calretinin mRNA expression levels in mouse brain tissue.

Rabies virus (RABV) infection leads to a fatal neurological outcome in humans and animals and is associated with major alterations in cellular gene expression. In this study, we describe the effects of RABV infection on the mRNA expression levels of two genes, encoding the Ca2+-binding proteins (Ca-BPs) calbindin D-28K (Calb1) and calretinin (Calb2), in the brains of BALB/c mice. Sixty 4-week-old mice were divided into two test groups and one control group. Mice were inoculated intramuscularly with either a street rabies virus (SRV) strain or a challenge virus standard (CVS-11) strain and sacrificed at 3-day intervals up to day 18 postinfection. A direct fluorescent antibody test (DFAT) was used to verify the presence of RABV antigen in brain tissues, and real-time quantitative PCR (RT-PCR) was used to assess gene expression. Infection with both RABV strains resulted in significant (p < 0.05) increases in Calb1 and Calb2 expression in the test animals when compared with the controls at various time points in the study. Correlation analysis indicated very weak insignificant (p > 0.05) negative and positive relationships, respectively, between Calb1 expression (r = -0.04) and Calb2 expression (r = 0.08) with viral load (CVS-11 strain). Insignificant (p > 0.05) relationships were also observed Calb1 expression (r = -0.28) and Calb2 expression (r = 0.06) and viral load for the SRV strain.The observed alterations in Calb1 and Calb2 expression in this study indicate possible impairments in neuronal Ca2+ buffering and Ca2+ homeostasis as a result of RABV infection and, consequently, possible involvement of calbindin-D28K and calretinin in the neuropathogenesis of rabies.

Serum Calretinin and Genetic Variability as a Prognostic and Predictive Factor in Malignant Mesothelioma.

Calretinin is a promising diagnostic biomarker for malignant mesothelioma (MM), but less is known about its prognostic role. Our aim was to evaluate the association between serum calretinin concentration or genetic factors and the survival or outcome of cisplatin-based chemotherapy in MM. Our study included 265 MM patients. Serum calretinin concentration was determined using ELISA. Patients were genotyped for seven polymorphisms in CALB2, E2F2, MIR335, NRF1, and SEPTIN7 using competitive allele-specific PCR. Nonparametric tests, logistic regression, and survival analysis were used for statistical analysis. Higher serum calretinin concentration was associated with shorter progression-free (PFS) (HR = 1.18 (1.02-1.37), p = 0.023) and overall survival (OS) (HR = 1.20 (1.03-1.41), p = 0.023), but the association was not significant after adjusting for clinical factors (HR = 1.05 (0.85-1.31), p = 0.653 and HR = 1.06 (0.84-1.34), p = 0.613, respectively). SEPTIN7 rs3801339 and MIR335 rs3807348 were associated with survival even after adjustment (HR = 1.76 (1.17-2.64), p = 0.007 and HR = 0.65 (0.45-0.95), p = 0.028, respectively). Calretinin concentration was higher in patients who progressed after treatment with cisplatin-based chemotherapy (1.68 vs. 0.45 ng/mL, p = 0.001). Calretinin concentration above 0.89 ng/mL was associated with shorter PFS and OS from the start of chemotherapy (HR = 1.88 (1.28-2.77), p = 0.001 and HR = 1.91 (1.22-2.97), p = 0.004, respectively), even after adjusting for clinical factors (p < 0.05). MIR335 rs3807348 was associated with a better response to chemotherapy (OR = 2.69 (1.17-6.18), p = 0.020). We showed that serum calretinin is associated with survival and chemotherapy treatment outcomes in MM and could serve as a predictive biomarker.

Assessment of miR-103a-3p in leukocytes-No diagnostic benefit in combination with the blood-based biomarkers mesothelin and calretinin for malignant pleural mesothelioma diagnosis.

Malignant pleural mesothelioma (MPM) is a cancer associated with asbestos exposure and its diagnosis is challenging due to the moderate sensitivities of the available methods. In this regard, miR-103a-3p was considered to increase the sensitivity of established biomarkers to detect MPM. Its behavior and diagnostic value in the Mexican population has not been previously evaluated. In 108 confirmed MPM cases and 218 controls, almost all formerly exposed to asbestos, we quantified miR-103-3a-3p levels in leukocytes using quantitative Real-Time PCR, together with mesothelin and calretinin measured in plasma by ELISA. Sensitivity and specificity of miR-103-3a-3p alone and in combination with mesothelin and calretinin were determined. Bivariate analysis was performed using Mann-Whitney U test and Spearman correlation. Non-conditional logistic regression models were used to calculate the area under curve (AUC), sensitivity, and specificity for the combination of biomarkers. Mesothelin and calretinin levels were higher among cases, remaining as well among males and participants ≤60 years old (only mesothelin). Significant differences for miR-103a-3p were observed between male cases and controls, whereas significant differences between cases and controls for mesothelin and calretinin were observed in men and women. At 95.5% specificity the individual sensitivity of miR-103a-3p was 4.4% in men, whereas the sensitivity of mesothelin and calretinin was 72.2% and 80.9%, respectively. Positive correlations for miR-103a-3p were observed with age, environmental asbestos exposure, years with diabetes mellitus, and glucose levels, while negative correlations were observed with years of occupational asbestos exposure, creatinine, erythrocytes, direct bilirubin, and leukocytes. The addition of miR-103a-3p to mesothelin and calretinin did not increase the diagnostic performance for MPM diagnosis. However, miR-103a-3p levels were correlated with several characteristics in the Mexican population.

Tissue- and cell-type-specific molecular and functional signatures of 16p11.2 reciprocal genomic disorder across mouse brain and human neuronal models.

Chromosome 16p11.2 reciprocal genomic disorder, resulting from recurrent copy-number variants (CNVs), involves intellectual disability, autism spectrum disorder (ASD), and schizophrenia, but the responsible mechanisms are not known. To systemically dissect molecular effects, we performed transcriptome profiling of 350 libraries from six tissues (cortex, cerebellum, striatum, liver, brown fat, and white fat) in mouse models harboring CNVs of the syntenic 7qF3 region, as well as cellular, transcriptional, and single-cell analyses in 54 isogenic neural stem cell, induced neuron, and cerebral organoid models of CRISPR-engineered 16p11.2 CNVs. Transcriptome-wide differentially expressed genes were largely tissue-, cell-type-, and dosage-specific, although more effects were shared between deletion and duplication and across tissue than expected by chance. The broadest effects were observed in the cerebellum (2,163 differentially expressed genes), and the greatest enrichments were associated with synaptic pathways in mouse cerebellum and human induced neurons. Pathway and co-expression analyses identified energy and RNA metabolism as shared processes and enrichment for ASD-associated, loss-of-function constraint, and fragile X messenger ribonucleoprotein target gene sets. Intriguingly, reciprocal 16p11.2 dosage changes resulted in consistent decrements in neurite and electrophysiological features, and single-cell profiling of organoids showed reciprocal alterations to the proportions of excitatory and inhibitory GABAergic neurons. Changes both in neuronal ratios and in gene expression in our organoid analyses point most directly to calretinin GABAergic inhibitory neurons and the excitatory/inhibitory balance as targets of disruption that might contribute to changes in neurodevelopmental and cognitive function in 16p11.2 carriers. Collectively, our data indicate the genomic disorder involves disruption of multiple contributing biological processes and that this disruption has relative impacts that are context specific.

Quality assurance of hematopoietic stem cells by macrophages determines stem cell clonality.

Tissue-specific stem cells persist for a lifetime and can differentiate to maintain homeostasis or transform to initiate cancer. Despite their importance, there are no described quality assurance mechanisms for newly formed stem cells. We observed intimate and specific interactions between macrophages and nascent blood stem cells in zebrafish embryos. Macrophage interactions frequently led to either removal of cytoplasmic material and stem cell division or complete engulfment and stem cell death. Stressed stem cells were marked by surface Calreticulin, which stimulated macrophage interactions. Using cellular barcoding, we found that Calreticulin knock-down or embryonic macrophage depletion reduced the number of stem cell clones that established adult hematopoiesis. Our work supports a model in which embryonic macrophages determine hematopoietic clonality by monitoring stem cell quality.

BDNF Val66Met genotype and adolescent glucocorticoid treatment induce sex-specific disruptions to fear extinction and amygdala GABAergic interneuron expression in mice.

BACKGROUND: The BDNF Val66Met single nucleotide polymorphism has been implicated in stress sensitivity and Post-Traumatic Stress Disorder (PTSD) risk. We previously reported that chronic young-adult stress hormone treatment enhanced fear memory in adult BDNFVal66Met mice with the Met/Met genotype. This study aimed to extend this work to fear extinction learning, spontaneous recovery of fear, and neurobiological correlates in the amygdala. METHODS: Male and female Val/Val and Met/Met mice received corticosterone in their drinking water during late adolescence to model chronic stress. Following a 2-week recovery period, the mice underwent fear conditioning and extinction training. Immunofluorescent labelling was used to assess density of three interneuron subtypes; somatostatin, parvalbumin and calretinin, within distinct amygdala nuclei. RESULTS: No significant effects of genotype, treatment or sex were found for fear learning. However, adolescent CORT treatment selectively abolished fear extinction of female Met/Met mice. No effect of genotype, sex, or treatment was observed for spontaneous recovery of fear. Significant main effects of genotype and CORT emerged for somatostatin and calretinin cell density, again in females only, further supporting sex-specific effects of the Met/Met genotype and chronic CORT exposure. CONCLUSION: BDNF Val66Met genotype interacts with chronic adolescent stress hormone exposure to abolish fear extinction in female Met/Met mice in adulthood. This effect was associated with female-specific interneuron dysfunction induced by either genotype or stress hormone exposure, depending on the interneuron subtype. These data provide biological insight into the role of BDNF in sex differences in sensitivity to stress and vulnerability to stress-related disorders in adulthood.

All-Ion Monitoring-Directed Low-Abundance Protein Quantification Reveals CALB2 as a Key Promoter in Hepatocellular Carcinoma Metastasis.

Because of the wide abundance range of the proteome, achieving high-coverage quantification of low-abundance proteins is always a major challenge. In this study, a complete pipeline focused on all-ion monitoring (AIM) is first constructed with the concept of untargeted parallel-reaction monitoring, including the seamless connection of protein sample preparation, liquid chromatography mass spectrometry (LC-MS) acquisition, and algorithm development to enable the in-depth quantitative analysis of low-abundance proteins. This pipeline significantly improves the reproducibility and sensitivity of sample preparation and LC-MS acquisition for low-abundance proteins, enabling all the precursors ions fragmented and collected. Contributed by the advantages of the AIM method with all the target precursor acquisition by the data-dependent acquisition (DDA) approach, together with the ability of data-independent acquisition to fragment all precursor ions, the quantitative accuracy and precision of low-abundance proteins are greatly enhanced. As a proof of concept, this pipeline is employed to discover the key differential proteins in the mechanism of hepatocellular carcinoma (HCC) metastasis. On the basis of the superiority of AIM, an extremely low-abundance protein, CALB2, is proposed to promote HCC metastasis in vitro and in vivo. We also reveal that CALB2 activates the TRPV2-Ca2+-ERK1/2 signaling pathway to induce HCC cell metastasis. In summary, we provide a universal AIM pipeline for the high-coverage quantification of low-abundance functional proteins to seek novel insights into the mechanisms of cancer metastasis.

CLDN15 is a novel diagnostic marker for malignant pleural mesothelioma.

Malignant mesothelioma is a cancer with a poor survival rate. It is difficult to diagnose mesotheliomas because they show a variety of histological patterns similar to those of various other cancers. However, since currently used positive markers for mesotheliomas may show false positives or false negatives, a novel mesothelial positive marker is required. In the present study, we screened 25 claudins and found that claudin-15 is expressed in the mesothelial cells. We made new rat anti-human claudin-15 (CLDN15) monoclonal antibodies that selectively recognize CLDN15, and investigated whether CLDN15 is a good positive marker for malignant pleural mesotheliomas (MPMs) using MPM tissue samples by immunohistochemistry and semi-quantification of the expression level using an immunoreactive score (IRS) method. Of 42 MPM samples, 83% were positive for CLDN15. The positive ratio was equal to or greater than other positive markers for MPMs including calretinin (81%), WT-1 (50%), and D2-40 (81%). In 50 lung adenocarcinoma sections, four cases were positive for CLDN15 and the specificity (92%) was comparable with other markers (90-100%). Notably, CLDN15 was rarely detected in 24 non-mesothelial tumors in the tissue microarray (12/327 cases). In conclusion, CLDN15 can be used in the clinical setting as a positive marker for MPM diagnosis.

Whole-genome sequencing of African Americans implicates differential genetic architecture in inflammatory bowel disease.

Whether or not populations diverge with respect to the genetic contribution to risk of specific complex diseases is relevant to understanding the evolution of susceptibility and origins of health disparities. Here, we describe a large-scale whole-genome sequencing study of inflammatory bowel disease encompassing 1,774 affected individuals and 1,644 healthy control Americans with African ancestry (African Americans). Although no new loci for inflammatory bowel disease are discovered at genome-wide significance levels, we identify numerous instances of differential effect sizes in combination with divergent allele frequencies. For example, the major effect at PTGER4 fine maps to a single credible interval of 22 SNPs corresponding to one of four independent associations at the locus in European ancestry individuals but with an elevated odds ratio for Crohn disease in African Americans. A rare variant aggregate analysis implicates Ca2+-binding neuro-immunomodulator CALB2 in ulcerative colitis. Highly significant overall overlap of common variant risk for inflammatory bowel disease susceptibility between individuals with African and European ancestries was observed, with 41 of 241 previously known lead variants replicated and overall correlations in effect sizes of 0.68 for combined inflammatory bowel disease. Nevertheless, subtle differences influence the performance of polygenic risk scores, and we show that ancestry-appropriate weights significantly improve polygenic prediction in the highest percentiles of risk. The median amount of variance explained per locus remains the same in African and European cohorts, providing evidence for compensation of effect sizes as allele frequencies diverge, as expected under a highly polygenic model of disease.

Mesothelioma Biomarkers: Discovery in Search of Validation.

Malignant pleural mesothelioma (MPM) is an asbestos-related neoplasm that can only be treated successfully when correctly diagnosed and treated early. The asbestos-exposed population is a high-risk group that could benefit from sensitive and specific blood- or tissue-based biomarkers. We review recent work with biomarker development in MPM and literature of the last 20 years on the most promising blood- and tissue-based biomarkers. Proteomic, genomic, and epigenomic platforms are covered. SMRP is the only validated blood-based biomarker with diagnostic, monitoring and prognostic value. To strengthen development and testing of MPM biomarkers, cohorts for validation must be established by enlisting worldwide collaborations.

[Mutant calreticulin and the molecular mechanisms in development of myeloproliferative neoplasms].

This review aimed to evaluate the molecular mechanism underlying the development of myeloproliferative neoplasms (MPN) caused by mutant calreticulin (CALR). This mutation is found in a subset of patients with Philadelphia chromosome-negative MPNs, and it encodes a molecular chaperone. However, it is essentially impossible to elucidate the oncogenic property of mutant CALR from the wild-type CALR function. Studies have reported that mutant CALR forms a homomultimeric complex via intermolecular interaction between novel domains acquired due to a frameshift mutation, gains a high binding affinity for myeloproliferative leukemia protein (MPL), the thrombopoietin receptor, through a presumptive structural change, and acts as an agonist for MPL. In this review, I would like to describe the course of the discovery of this unique molecular mechanism and discuss future scope of research on mutant CALR.

Loss of Hippocampal Calretinin and Parvalbumin Interneurons in the 5XFAD Mouse Model of Alzheimer's Disease.

The deposition of amyloid-ß peptides in the form of extracellular plaques and neuronal degeneration belong to the hallmark features of Alzheimer's disease (AD). In addition, impaired calcium homeostasis and altered levels in calcium-binding proteins seem to be associated with the disease process. In this study, calretinin- (CR) and parvalbumin- (PV) positive gamma-aminobutyric acid-producing (GABAergic) interneurons were quantified in different hippocampal subfields of 12-month-old wild-type mice, as well as in the transgenic AD mouse models 5XFAD and Tg4-42. While, in comparison with wild-type mice, CR-positive interneurons were mainly reduced in the CA1 and CA2/3 regions in plaque-bearing 5XFAD mice, PV-positive interneurons were reduced in all analyzed subfields including the dentate gyrus. No reduction in CR- and PV-positive interneuron numbers was detected in the non-plaque-forming Tg4-42 mouse, although this model has been previously demonstrated to harbor a massive loss of CA1 pyramidal neurons. These results provide information about hippocampal interneuron numbers in two relevant AD mouse models, suggesting that interneuron loss in this brain region may be related to extracellular amyloid burden.

Modulation of Calretinin Expression in Human Mesothelioma Cells Reveals the Implication of the FAK and Wnt Signaling Pathways in Conferring Chemoresistance towards Cisplatin.

Malignant mesothelioma (MM) is an aggressive asbestos-linked neoplasm, characterized by dysregulation of signaling pathways. Due to intrinsic or acquired chemoresistance, MM treatment options remain limited. Calretinin is a Ca2+-binding protein expressed during MM tumorigenesis that activates the FAK signaling pathway, promoting invasion and epithelial-to-mesenchymal transition. Constitutive calretinin downregulation decreases MM cells' growth and survival, and impairs tumor formation in vivo. In order to evaluate early molecular events occurring during calretinin downregulation, we generated a tightly controlled IPTG-inducible expression system to modulate calretinin levels in vitro. Calretinin downregulation significantly reduced viability and proliferation of MM cells, attenuated FAK signaling and reduced the invasive phenotype of surviving cells. Importantly, surviving cells showed a higher resistance to cisplatin due to increased Wnt signaling. This resistance was abrogated by the Wnt signaling pathway inhibitor 3289-8625. In various MM cell lines and regardless of calretinin expression levels, blocking of FAK signaling activated the Wnt signaling pathway and vice versa. Thus, blocking both pathways had the strongest impact on MM cell proliferation and survival. Chemoresistance mechanisms in MM cells have resulted in a failure of single-agent therapies. Targeting of multiple components of key signaling pathways, including Wnt signaling, might be the future method-of-choice to treat MM.

Sonic Hedgehog is expressed by hilar mossy cells and regulates cellular survival and neurogenesis in the adult hippocampus.

Sonic hedgehog (Shh) is a multifunctional signaling protein governing pattern formation, proliferation and cell survival during embryogenesis. In the adult brain, Shh has neurotrophic function and is implicated in hippocampal neurogenesis but the cellular source of Shh in the hippocampus remains ill defined. Here, we utilize a gene expression tracer allele of Shh (Shh-nlacZ) which allowed the identification of a subpopulation of hilar neurons known as mossy cells (MCs) as a prominent and dynamic source of Shh within the dentate gyrus. AAV-Cre mediated ablation of Shh in the adult dentate gyrus led to a marked degeneration of MCs. Conversely, chemical stimulation of hippocampal neurons using the epileptogenic agent kainic acid (KA) increased the number of Shh+ MCs indicating that the expression of Shh by MCs confers a survival advantage during the response to excitotoxic insults. In addition, ablation of Shh in the adult dentate gyrus led to increased neural precursor cell proliferation and their migration into the subgranular cell layer demonstrating that MCs-generated Shh is a key modulator of hippocampal neurogenesis.

Calretinin positive neurons form an excitatory amplifier network in the spinal cord dorsal horn.

Nociceptive information is relayed through the spinal cord dorsal horn, a critical area in sensory processing. The neuronal circuits in this region that underpin sensory perception must be clarified to better understand how dysfunction can lead to pathological pain. This study used an optogenetic approach to selectively activate spinal interneurons that express the calcium-binding protein calretinin (CR). We show that these interneurons form an interconnected network that can initiate and sustain enhanced excitatory signaling, and directly relay signals to lamina I projection neurons. Photoactivation of CR interneurons in vivo resulted in a significant nocifensive behavior that was morphine sensitive, caused a conditioned place aversion, and was enhanced by spared nerve injury. Furthermore, halorhodopsin-mediated inhibition of these interneurons elevated sensory thresholds. Our results suggest that dorsal horn circuits that involve excitatory CR neurons are important for the generation and amplification of pain and identify these interneurons as a future analgesic target.

A 2-year retrospective study on pleural effusions: A cancer centre experience.

BACKGROUND: Cytopathological examination of pleural effusions is a fast and minimally invasive method for verification of the presence of neoplastic cells. We report our 2-year experience using a categorised diagnostic system and reporting risks of malignancy (ROMs) for each defined category. METHODS: Cytological reports of patients between November 2016 and October 2018 were collected, with results primarily classified into a five-tiered classification scheme. Immunohistochemistry markers used in cytology and their results were also recorded. Final agreement to histology and overall test performance was calculated for cases with available concomitant (up to 3 months) pleural biopsies. RESULTS: A total of 519 samples from 385 patients were collected, being 29 (5.6%) classified as non-diagnostic, 291 (56%) as negative, 28 (5.4%) as atypical, 30 (5.8%) as suspicious and 141 (27.2%) as positive. Most requested markers were calretinin, TTF1, Ber-EP4 and Gata-3, being conclusive in 45 (76.3%) cases. Total cyto-histological agreement was achieved in 49 (80.3%) specimens, with an overall sensitivity and specificity of 69.4% and 93.3%, respectively. Positive predictive value was 96.2% and negative predictive value was of 56%. ROM for each diagnostic category was 50% for non-diagnostic, 44% for negative, 50% for atypical, 83.3% for suspicious and 96.2% for positive. CONCLUSIONS: Our 2-year retrospective study has shown a high specificity and positive predictive value for pleural cytology. The use of a five-tiered system has also shown to be highly effective, with a concordantly progressive higher ROM for the assigned diagnostic categories.

The lower expression of parvalbumin in the primary somatosensory cortex of WAG/Rij rats may facilitate the occurrence of absence seizures.

Absence epilepsy (AE) is classified as a genetic generalized epilepsies. WAG/Rij strain of rats are regarded one of the most validated models of absence epilepsy. Studies point out the existence of hyperexcitable focus in somatosensory cortex of these rats, which has been attributed to the deficits in the GABAergic system. In the current study, we studied the changes of calcium binding proteins (CaBPs) in somatosensory cortex (S1) of the 2 and 8 month-old WAG/Rij rats and their age-matched Wistar Albino controls by investigating the expression levels of CaBPs (calbindin, calretinin and parvalbumin) in western blotting. Since WAG/Rij rats showed the low expression level of parvalbumin (PV) in western blots in comparison to Wistar Albino rats, we selectively investigated the number of PV positive neurons using the immunofluorescence staining method in order to confirm this decrement in the perioral region of somatosensory cortex (S1po). The most critical finding of this study was the age- independent reduction in the expression level of PV in the somatosensory cortex of epileptic rats as demonstrating western blotting. Nevertheless, no significant difference was found among numbers of PV + neuron in the S1po region by immunofluorescence staining concerning both of age and strain dependency. These results suggest that the disruption in the activity of the PV-expressing GABAergic interneurons might be involved in the generation of rather than the age-dependent increase in the SWDs in WAG/Rij rats.