Comparative evaluation of bond strength of diode and neodymium-doped:Yttrium aluminum garnet-assisted bleached enamel with nanofilled composite: An in vitro study.

Background: The world of esthetic dentistry is constantly making efforts toward the management of tooth staining. Laser-assisted bleaching is needed before adhesive restorations and has become common and advantageous as it accelerates bleaching action, reduces postoperative sensitivity, and promotes recrystallization of enamel. Aim: The study aimed to evaluate and compare the bond strength of diode (Biolace: EpicX) and neodymium-doped:yttrium aluminum garnet (Nd:YAG) (LightWalker, Fotona, Slovenia) assisted bleached (Pola Office, SDI) enamel with nanofilled composite (GC Solare Sculpt). Materials and Methods: The samples were divided into three groups (n = 11): Group A - Conventionally bleached enamel, Group B - Diode laser-assisted bleached enamel, Group C - Nd:YAG laser-assisted bleached enamel. After storing samples in Artificial Saliva for 2 weeks, bonding was performed, and nanofilled composite resin was applied through an incremental method. Samples were subjected to shear bond strength (SBS) analysis. Conclusion: The use of Nd:YAG laser on bleached enamel significantly increases the bond strength with nanofilled composite resin.

Biogeographic patterns in populations of marine Pseudoalteromonas atlantica isolates.

Intra-specific genomic diversity is well documented in microbes. The question, however, remains whether natural selection or neutral evolution is the major contributor to this diversity. We undertook this study to estimate genomic diversity in Pseudoalteromonas atlantica populations and whether the diversity, if present, could be attributed to environmental factors or distance effects. We isolated and sequenced twenty-three strains of P. atlantica from three geographically distant deep marine basins and performed comparative genomic analyses to study the genomic diversity of populations among these basins. Average nucleotide identity followed a strictly geographical pattern. In two out of three locations, the strains within the location exhibited >99.5% identity, whereas, among locations, the strains showed <98.11% identity. Phylogenetic and pan-genome analysis also reflected the biogeographical separation of the strains. Strains from the same location shared many accessory genes and clustered closely on the phylogenetic tree. Phenotypic diversity between populations was studied in ten out of twenty-three strains testing carbon and nitrogen source utilization and osmotolerance. A genetic basis for phenotypic diversity could be established in most cases but was apparently not influenced by local environmental conditions. Our study suggests that neutral evolution may have a substantial role in the biodiversity of P. atlantica.

Mycotoxin tolerance affects larval competitive ability in Drosophila recens (Diptera: Drosophilidae).

Certain mycophagous Drosophila species are the only known eukaryotes that can tolerate some highly potent mycotoxins. This association between mycophagy and mycotoxin tolerance is well established because Drosophila species that switch hosts from mushrooms to other food sources lose their mycotoxin tolerance trait without any evolutionary lag. These findings suggest that mycotoxin tolerance may be a costly trait to maintain. In this study, we attempted to identify whether mycotoxin tolerance has a fitness cost. Larval competitive ability is a vital fitness trait, especially in holometabolous insects, where the larvae cannot move to a new host. Furthermore, larval competitive ability is known to be associated with many critical life-history traits. Here we studied whether mycotoxin tolerance adversely affects larval competitive ability on isofemale lines from 2 distinct locations. We observed that the extent of mycotoxin tolerance affected larval competitive ability, but only in isofemale lines from one location. Additionally, we observed that the high mycotoxin-tolerant isofemale lines from the same location showed poor survival to eclosion. This study shows that mycotoxin tolerance is associated with fitness costs and provides preliminary evidence of an association between local adaptation and mycotoxin tolerance.

Comparative evaluation of penetration of sealers in dentinal tubules using passive ultrasonic irrigation and Erbium: yttrium-aluminum-garnet laser - A confocal laser scanning microscope study.

Context: Smear layer clearance and sealer penetration into dentinal tubules play a crucial role in root canal treatment. Hence, efficient irrigation is a crucial component of the root canal debridement. This in vitro study's objective was to assess the effectiveness of passive ultrasonic activation and Erbium: yttrium-aluminum-garnet (Er: YAG) laser-activated irrigation on irrigation solution penetration and sealer penetration into dentinal tubules. Aims: The aim of this study was to evaluate and compare the dentinal tubule penetration of epoxy resin-based sealer and bioceramic sealer after ultrasonic agitation and Er: YAG laser activation of the irrigant. Settings and Design: This was an in vitro study. Materials and Methods: Extracted tooth samples (n = 42) into 06 groups (Group A-F) with 7 samples in each group. Postobturation transverse section was made and assessed under a confocal laser scanning microscope for the total dentinal tubule penetration area and recorded as the mean apical, middle, and coronal penetration. Statistical Analysis: One-way analysis of variance test, followed by post hoc was used. Results: The intergroup comparison showed that Group E and Group F have significantly more penetration as compared to the controls and ultrasonic irrigation, P < 0.001 and P < 0.01, respectively. Conclusions: Er: YAG laser with AH plus sealer has the highest penetration in all the sections of tooth, followed by CeraSeal sealer.

The regulation of a pigmentation gene in the formation of complex color patterns in Drosophila abdomens.

Changes in the control of developmental gene expression patterns have been implicated in the evolution of animal morphology. However, the genetic mechanisms underlying complex morphological traits remain largely unknown. Here we investigated the molecular mechanisms that induce the pigmentation gene yellow in a complex color pattern on the abdomen of Drosophila guttifera. We show that at least five developmental genes may collectively activate one cis-regulatory module of yellow in distinct spot rows and a dark shade to assemble the complete abdominal pigment pattern of Drosophila guttifera. One of these genes, wingless, may play a conserved role in the early phase of spot pattern development in several species of the quinaria group. Our findings shed light on the evolution of complex animal color patterns through modular changes of gene expression patterns.

Derivative 6 as an additional chromosomal abnormality along with t(15;17): A case report.

Acute promyelocytic leukemia (APL) is a type of acute myeloid leukemia (AML) characterized by the presence of t(15;17)(q22;q21) translocation leading to fusion between PML and RARa gene. Treatment combining all-trans retinoic acid (ATRA) and arsenic trioxide (ATO) has dramatically improved the prognosis of APL. We report a rare finding of primary clone of t(15;17) followed by a sequential clonal evolution of additional derivative chromosome 6 formation by a two hit mechanism. Our case showed a good clinical response with a four years and nine months event free survival after ATRA and ATO combination therapy in spite of existence of three chromosomal abnormalities stating that targeted therapy overcomes the adverse effects of additional genetic markers. However, close monitoring with assessment for long term prognostic behavior is required.

Inter- and intraspecific variation in mycotoxin tolerance: A study of four Drosophila species.

Many mycophagous Drosophila species have adapted to tolerate high concentrations of mycotoxins, an ability not reported in any other eukaryotes. Although an association between mycophagy and mycotoxin tolerance has been established in many Drosophila species, the genetic mechanisms of the tolerance are unknown. This study presents the inter- and intraspecific variation in the mycotoxin tolerance trait. We studied the mycotoxin tolerance in four Drosophila species from four separate clades within the immigrans-tripunctata radiation from two distinct locations. The effect of mycotoxin treatment on 20 isofemale lines per species was studied using seven gross phenotypes: survival to pupation, survival to eclosion, development time to pupation and eclosion, thorax length, fecundity, and longevity. We observed interspecific variation among four species, with D. falleni being the most tolerant, followed by D. recens, D. neotestacea, and D. tripunctata, in that order. The results also revealed geographical variation and intraspecific genetic variation in mycotoxin tolerance. This report provides the foundation for further delineating the genetic mechanisms of the mycotoxin tolerance trait.

Neural circuit mechanisms of hierarchical sequence learning tested on large-scale recording data.

The brain performs various cognitive functions by learning the spatiotemporal salient features of the environment. This learning requires unsupervised segmentation of hierarchically organized spike sequences, but the underlying neural mechanism is only poorly understood. Here, we show that a recurrent gated network of neurons with dendrites can efficiently solve difficult segmentation tasks. In this model, multiplicative recurrent connections learn a context-dependent gating of dendro-somatic information transfers to minimize error in the prediction of somatic responses by the dendrites. Consequently, these connections filter the redundant input features represented by the dendrites but unnecessary in the given context. The model was tested on both synthetic and real neural data. In particular, the model was successful for segmenting multiple cell assemblies repeating in large-scale calcium imaging data containing thousands of cortical neurons. Our results suggest that recurrent gating of dendro-somatic signal transfers is crucial for cortical learning of context-dependent segmentation tasks.

Codon usage bias and dinucleotide preference in 29 Drosophila species.

Codon usage bias, where certain codons are used more frequently than their synonymous counterparts, is an interesting phenomenon influenced by three evolutionary forces: mutation, selection, and genetic drift. To better understand how these evolutionary forces affect codon usage bias, an extensive study to detect how codon usage patterns change across species is required. This study investigated 668 single-copy orthologous genes independently in 29 Drosophila species to determine how the codon usage patterns change with phylogenetic distance. We found a strong correlation between phylogenetic distance and codon usage bias and observed striking differences in codon preferences between the two subgenera Drosophila and Sophophora. As compared to the subgenus Sophophora, species of the subgenus Drosophila showed reduced codon usage bias and a reduced preference specifically for codons ending with C, except for codons with G in the second position. We found that codon usage patterns in all species were influenced by the nucleotides in the codon's 2nd and 3rd positions rather than the biochemical properties of the amino acids encoded. We detected a concordance between preferred codons and preferred dinucleotides (at positions 2 and 3 of codons). Furthermore, we observed an association between speciation, codon preferences, and dinucleotide preferences. Our study provides the foundation to understand how selection acts on dinucleotides to influence codon usage bias.

The modular expression patterns of three pigmentation genes prefigure unique abdominal morphologies seen among three Drosophila species.

To understand how novel animal body colorations emerged, one needs to ask how the development of color patterns differs among closely related species. Here we examine three species of fruit flies - Drosophila guttifera (D. guttifera), D. palustris, and D. subpalustris - displaying a varying number of abdominal spot rows. Through in situ hybridization experiments, we examine the mRNA expression patterns for the pigmentation genes Dopa decarboxylase (Ddc), tan (t), and yellow (y) during pupal development. Our results show that Ddc, t, and y are co-expressed in modular, identical patterns, each foreshadowing the adult abdominal spots in D. guttifera, D. palustris, and D. subpalustris. We suggest that differences in the expression patterns of these three genes partially underlie the morphological diversity of the quinaria species group.

Status of TMPRSS2-ERG fusion in prostate cancer patients from India: correlation with clinico-pathological details and TMPRSS2 Met160Val polymorphism.

BACKGROUND: Prostate cancer (PCa) shows considerable clinical heterogeneity that has been primarily attributed to variable molecular alterations. TMPRSS2-ERG fusion is one such molecular subtype that has been associated with predominantly poor prognosis. More recently, a single nucleotide polymorphism (SNP) in the TMPRSS2 gene rs12329760 C>T (Met160Val) has been shown to positively correlate with the fusion status and also to be associated with increased risk for PCa. The aim of the present study is to determine the frequency of TMPRSS2-ERG fusion and association of rs12329760 in Indian PCa patients with fusion status. METHODS: TMPRSS2-ERG fusion by fluorescence in situ hybridization was determined in 102 of 150 PCa biopsy-proven cases. Genotyping for rs12329760 was performed on the entire cohort of 150 cases by Sanger sequencing. RESULTS: TMPRSS2-ERG fusion was seen in 27 of 102 (26%) cases. Fusion-positive patterns in this study showed fusion by translocation in nine of 27 cases (33.5%), by deletion in six of 27 (22%) cases, and by insertion in 12 of 27 cases (44.5%). No association of the fusion status with Gleason Score, pattern, or perineural invasion was seen. The TMPRSS2 SNP rs12329760 'T' allele was prevalent with a frequency of 0.27 in the PCa patients. The SNP was significantly associated with fusion [odds ratio (OR) = 2.176, 95% confidence interval (CI) = 1.012-4.684, P = 0.04], more specifically fusion by deletion (P = 0.04). CONCLUSION: The results provided here determine the frequency of TMPRSS2-ERG fusions (26%) in a fairly large cohort of Indian PCa cases and also the association of rs12329760 SNP with TMPRSS2-ERG fusion. No association with other clinico-pathological features was observed. Future studies with clinical outcomes are warranted in this population.

Prognostic classification of MDS is improved by the inclusion of FISH panel testing with conventional cytogenetics.

Cytogenetics is a critical independent prognostic factor in myelodysplastic syndromes (MDS). Conventional cytogenetics (CC) and Fluorescence in situ hybridization (FISH) Panel Testing are extensively used for the prognostic stratification of MDS, although the FISH test is not yet a bona fide component of the International Prognostic Scoring System (IPSS). The present study compares the utility of CC and FISH to detect chromosomal anomalies and in prognostic categorization. GTG-Banding and FISH Panel Testing specifically for -5/-5q, -7/-7q, +8 and -20q was performed on whole blood or bone marrow samples from 136 patients with MDS. Chromosomal anomalies were found in 40 cases by CC, including three novel translocations. FISH identified at least one anomaly in 54/136 (39.7%) cases. More than one anomaly was found in 18/54 (33.3%) cases, therefore, overall FISH identified 75 anomalies of which 32 (42.6%) were undetected by CC. FISH provided additional information in cases with CC failure and in cases with a normal karyotype. Further, in ten cases with an abnormal karyotype, FISH could identify additional anomalies, increasing the number of abnormalities per patient. Although CC is the gold standard in the cytogenetic profiling of MDS, FISH has proven to be an asset in identifying additional abnormalities. The number of anomalies per patient can predict the prognosis in MDS and hence, FISH contributed towards prognostic re-categorization. The FISH Panel testing should be used as an adjunct to CC, irrespective of the adequacy of the number of metaphases in CC, as it improves the prognostic classification of MDS.

Cytogenetic Profile of De Novo B lineage Acute Lymphoblastic Leukemia: Determination of Frequency, Distribution Pattern and Identification of Rare and Novel Chromosomal Aberrations in Indian Patients.

BACKGROUND: Chromosomal aberrations identified in acute lymphoblastic leukemia (ALL) have an important role in disease diagnosis, prognosis and management. Information on karyotype and associated clinical parameters are essential to physicians for planning cancer control interventions in different geographical regions. MATERIALS AND METHODS: In this study, we present the overall frequency and distribution patterns of chromosomal aberrations in both children and adult de novo B lineage ALL Indian patients using conventional cytogenetics, interphase FISH and multiplex RT-PCR. RESULTS: Among the 215 subjects, cytogenetic results were achieved in 172 (80%) patients; normal karyotype represented 37.2% and abnormal 62.8% with a distribution as follows: 15.3% hypodiploidy; 10.3% hyperdiploidy; 15.8% t(9;22); 9.8% t(1;19); 3.7% t(12;21); 2.8% t(4;11); 2.8% complex karyotypes. Apart from these, we observed several novel, rare and common chromosomal rearrangements. Also, FISH studies using LSI extra-signal dual-color probes revealed additional structural or numerical changes. CONCLUSIONS: These results demonstrate cytogenetic heterogeneity of ALL and confirm that the incidence of chromosomal abnormalities varies considerably. To the best of our knowledge, this is one of the largest reported series of cytogenetic investigations in Indian B-lineage ALL cases. In addition, ongoing cytogenetic studies are warranted in larger groups of B-lineage ALL cases to identify newly acquired chromosomal abnormalities that may contribute to disease diagnosis and management.

A complex three-way translocation with deletion of the TP53 gene in a blast crisis chronic myeloid leukemia patient.

Chronic myeloid leukemia (CML) is characterized by the Philadelphia (Ph) chromosome created by the reciprocal translocation t(9;22) (q34;q11), resulting in the chimeric BCR-ABL oncogene. Variant Ph' chromosome translocations involving additional chromosomes are seen in 5-10% of CML cases. In the present study, a novel case of Ph' chromosome-positive CML is reported, with a three-way translocation involving chromosomal regions, 9q34, 22q11.2 and 17p11.2, with additional secondary changes. The three-way translocation has resulted in a deletion of the TP53 gene located on the chromosome 17p13.1 locus. Deletion of the TP53 gene may be a major contributing factor in the development of resistance to imatinib and blast crisis.

Evaluation of genetic status of HER-2/neu and aneusomy 17 by fluorescence in situ hybridization and comparison with immunohistochemistry assay from Indian breast cancer patients.

AIMS: The HER-2/neu proto-oncogene is amplified in 15%-25% of breast cancers. In the current study, we evaluated HER-2/neu status of 396 cases of breast cancer by fluorescence in situ hybridization (FISH), and the results were correlated with immunohistochemistry (IHC) for HER-2/neu protein expression. RESULTS: Overall, HER-2/neu amplification was observed in 38.4% of cases. Concordance between IHC and FISH was 90.4% considering only IHC score 0, 1 (negative), and 3 (positive). However, only 37.3% of the IHC score 2 (equivocal) cases showed HER-2/neu gene amplification. A majority of the discordant cases within the IHC negative (score 0 and 1) and IHC positive (score 3) were high-grade tumors. Polysomy 17 and monosomy 17 was seen in 7.3% of the total cases of each. Furthermore, a majority of FISH positive cases were noted in Intraductal Carcinoma grade III and cases with regional lymph nodal metastasis. Polysomy 17 was seen in 7.9% of the FISH positive cases and in 6.3% of the FISH negative cases. Monosomy 17, however was more preponderant in FISH negative cases. CONCLUSION: We believe that the FISH test should be considered as the gold standard in the estimation of the HER-2/neu status due to its increased sensitivity and better appreciation of aneusomy 17.

Molecular cytogenetic investigations in a novel complex variant of t(8;21)(q22;q22) with ins(15;21)(q15;q22.2q22.3) in a patient with AML-M2 subtype.

Acute myeloid leukemia (AML) is a clinically and molecularly heterogeneous disease characterized by the aberrant proliferation of myeloid stem cells, reduced apoptosis and blockage in cellular differentiation. The present report describes the results of hematological, cytogenetic, and fluorescence in situ hybridization (FISH) analysis in a 25-year-old man diagnosed with AML-M2. Cytogenetic as well as FISH analysis revealed a complex translocation involving four chromosomes, with the karyotype 45,-Y,der(X)t(X;8)(p21;q22),der(8)t(8;21)(q22;q22),ins(15;21)(q15;q22.2q22.3),der(21)t(8;21)(q22;q22). The breakpoints at 8q22 and 21q22 suggested a rearrangement of the RUNX1T1 (alias ETO) and RUNX1 (previously AML1) genes, respectively. Using a dual-color FISH test with RUNX1T1 and RUNX1 probes, we demonstrated an RUNX1/RUNX1T1 fusion signal on the derivative chromosome 8, establishing this translocation as a novel complex variant of t(8;21)(q22;q22).

Molecular cytogenetic findings in a three-way novel variant of t(1;8;21)(p35;q22;q22): a unique relocation of the AML1/ETO fusion gene 1p35 in AML-M2.

Acute myeloid leukemia (AML) is a malignant neoplasm of hematopoietic stem cells characterized by an abnormal proliferation of myeloid precursors, a reduced rate of apoptosis, and an arrest in cellular differentiation. The present report deals with the results of hematologic, immunophenotypic, cytogenetic, fluorescence in situ hybridization (FISH), and molecular analyses of a 53-year-old female patient diagnosed with AML-M2. Cytogenetic and FISH analysis revealed a complex translocation involving three chromosomes showing t(1;8;21)(p35;q22;q22). The observation of breakpoints at 8q22 and 21q22 suggests a rearrangement of the ETO and AML1 genes, respectively. Using a dual-color FISH test with ETO and AML1 probes, an AML1/ETO fusion signal on the derivative 1p35 instead of der(8) was demonstrated. To the best of our knowledge, this is the first report about the relocation of the AML1/ETO fusion gene to the 1p35 rather than der(8), suggesting the presence of a novel variant of t(8;21)(q22;q22) in the observed patient.