Chromatin Bodies Research Articles

Gender Determination in Deciduous Pulp Tissue using Barr Bodies by Comparing Feulgen Stain, Acridine Orange, and Papanicolaou Stain

Background: Age, sex, stature, and ethnic background are considered a main attributes of biological identity of the individual, which are also called the “Big Four” in forensic. Human identification is of chief importance, in both legal and humanitarian purpose. Teeth can remain virtually unaffected and survive long after other soft tissue and skeletal tissues were destroyed. Hence, its implication in personal identification was gained popularity and high accuracy. Aim and Objective: The aim and objective of the study were to determine the reliability of gender determination from deciduous dental pulp tissue by comparing Feulgen stain, acridine orange, and Papanicolaou stain. Materials and Methods: This study was carried out on 25 samples, out of which 14 female teeth and 11 male teeth. The pulp was collected from the teeth undergoing pulpectomy. Then, the pulp tissue was transferred to the centrifuge tube containing Carnoy’s fixative. After centrifugation, the cells were collected and stained using Feulgen stain, acridine orange, and Papanicolaou stain. Results: The reliability of gender determination is significant, with the female shows 100% positive results and the male shows negative. The Papanicolaou stain shows better nuclear morphology while comparing with Feulgen and acridine orange. Conclusion: Hence, gender determination can be identified using deciduous dental pulp.

MICRONUCLEI IN SQUAMOUS CELL CARCINOMA

Micronuclei are small chromatin bodies that appear in the cytoplasm by the condensation of acrocentric chromosomal fragments or by whole chromosome, lagging behind the cell division.Micronuclei in oral exfoliated epithelial cells are widely used as a biomarker of chromosomal damage, genome instability and cancer risk in humans.In oral exfoliated cells these micronuclei are induced by variety of carcinogenic compounds ,which have been suggested to be most common cause of premalignant lesion ,conditions and oral cancer and thus can be used as a biomarker for cytogenetic damage.In this review ,the formation of these important nuclear anomalies that are commonly seen in cancer and are indicative of genome dmage that could increase the risk of developmental and degenerative diseases.

Loss of H3K27me3 in WHO grade 3 meningioma.

Immunohistochemical quantification of H3K27me3 was reported to distinguish meningioma patients with an unfavorable prognosis but is not yet established as a prognostic biomarker within WHO grade 3 meningiomas. We studied H3K27me3 loss in a series of biopsies from primary and secondary malignant meningioma to validate its prognostic performance and describe if loss of H3K27me3 occurs during malignant transformation. Two observers quantified H3K27me3 status as "complete loss", < 50% and > 50% stained cells in 110 tumor samples from a population-based consecutive cohort of 40 WHO grade 3 meningioma patients. We found no difference in overall survival (OS) in patients with > 50% H3K27me3 retention compared to < 50% in the cohort of patients with WHO grade 3 meningioma (Wald test p = 0.5). H3K27me3 staining showed heterogeneity in full section tumor slides while staining of the Barr body and peri-necrotic cells complicated quantification further. H3K27me3 expression differed without a discernible pattern between biopsies from repeated surgeries of meningioma recurrences. In conclusion, our results were not compatible with a systematic pattern of immunohistochemical H3K27me3 loss being associated with OS or malignant transformation of meningiomas and did not support H3K27me3 loss as a useful immunohistochemical biomarker within grade 3 meningiomas due to staining-specific challenges in quantification.

GENDER DETERMINATION METHOD USING BARR

Barr bodies have not yet been studied in depth by most scientists. There is not enough information about the effects of barr bodies on the body. Barr corpses are preserved from the zygotic period of the organism to the end of its life. A number of studies have been conducted in this regard. The use of barr bodies is very effective in determining the sex of organisms that show signs of both sexes. At present, barr bodies are not only used to determine the sex. descendants of hereditary diseases or symptoms We can also learn about how they appear, their effect on the body and the degree of occurrence of these conditions in the offspring.

50 Years Ago in TheJournalofPediatrics: From Chromosomes to Clinical Care: Klinefelter Syndrome

Caldwell PD, Smith DW. The XXY (Klinefelter's) syndrome in childhood: detection and treatment. J Pediatr 1972; 80:250-8. Classical dysmorphology was born, like so much of clinical medicine, from painstaking and careful clinical observation of unrelated individuals with shared clinical features. In this report, Caldwell and Smith take the subsequent steps toward broader understanding of the phenotype and treatment. They tackle the challenge of identifying individuals with a common syndrome before obvious presentation of features. They further dive into the now-modern era of treatment for genetic syndromes. Klinefelter syndrome was published in 1942 from observations during Klinefelter's fellowship at Mass General Hospital.1Klinefelter H.F. Reifenstein E.C. Albright F. Syndrome characterized by gynecomastia, aspermatogenesis without A-leydigism, and increased excretion of follicle-stimulating hormone.J Clin Endocrinol Metab. 1942; 2: 615-627Google Scholar Seventeen years later, the cause of Klinefelter syndrome was identified as an additional “X,” for a chromosome compliment of 47,XXY.2Jacobs P.A. Strong D.J.A. A case of human intersexuality having a possible XXY sex-determining mechanism.Nature. 1959; 183: 302-303Google Scholar This made Klinefelter syndrome the first sex chromosome aneuploidy identified—in predoctoral work by Patricia A. Jacobs. Prof Jacobs continues as a genomicist today, directing research at the University of Southampton in the United Kingdom. Despite the definition of Klinefelter syndrome as 47,XXY, the presence of a Barr body (“X chromatin positive”) in a phenotypic male subject often was used as an efficient “biomarker.” We now appreciate that this, in fact, included individuals with alternative diagnoses, including 46,XX sex reversal (eg, with SRY translocation). The challenge of parsing out a screen that merely suggests sex chromosome aneuploidy, and taking appropriate subsequent steps for a complete genetic diagnosis, continues today. In particular, this is an issue with noninvasive prenatal screening, where the positive predictive value for 47,XXY is a mean of 50%.3Cherry A.M. Akkari Y.M. Barr K.M. Kearney H.M. Rose N.C. South S.T. et al.Diagnostic cytogenetic testing following positive noninvasive prenatal screening results: a clinical laboratory practice resource of the American College of Medical Genetics and Genomics (ACMG).Genet Med. 2017; 19: 845-850Google Scholar We also understand now, in part thanks to efforts like that of Caldwell and Smith, that the phenotype of 47,XXY Klinefelter syndrome is broad. Even today, many individuals present initially for fertility evaluation, having experienced minimal learning or pubertal challenges, and yet more are identified now that noninvasive prenatal screening in pregnancy is commonplace regardless of maternal age. Treatment for Klinefelter is also broadening. Hormonal supplementation for those needing pubertal support is commonplace, and investigation is now focused on whether early pediatric hormonal support may benefit learning and neurologic outcomes.4Samango-Sprouse C.A. Tran S.L. Lasutschinkow P.C. Sadeghin T. Powell S. Mitchell F.L. et al.Neurodevelopmental outcome of prenatally diagnosed boys with 47,XXY (Klinefelter syndrome) and the potential influence of early hormonal therapy.Am J Med Genet A. 2020; 182: 1881-1889Google Scholar Where diagnosis using genetics and dysmorphology was once an end point unto itself, Caldwell and Smith's work is an early indication of the future of genomic medicine. Ultimately, prognostication alone is often insufficient. The goal of all pediatrics is improvement of health and outcomes, in this case using the identification of a syndrome as a tool to reach that goal.

Genetic diagnosis of pseudomyxoma peritonei originating from mucinous borderline tumor inside an ovarian teratoma

BackgroundPseudomyxoma peritonei is a rare disease condition mainly caused by primary mucinous tumors from the appendix and rarely from the ovary, such as when mucinous ovarian tumors arise from within a teratoma. Molecular analyses of pseudomyxoma from the appendix showed that KRAS and GNAS pathogenic variants are common genetic features of pseudomyxoma peritonei. However, the origin of the tumors is difficult to be identified via genetic variants alone. This study presents a case of pseudomyxoma peritonei of ovarian origin, which was diagnosed by comprehensive genomic profiling with ploidy analysis in a series of primary, recurrent, and autopsy tumor specimens.Case presentationA 40-year-old woman was diagnosed with Stage IC2 mucinous ovarian tumor of borderline malignancy with mature cystic teratoma, upon clinical pathology. Immunohistochemical analysis suggested that the mucinous tumor was derived from the intestinal component of an ovarian teratoma. Three years later, intraperitoneal recurrence was detected, which subsequently progressed to pseudomyxoma peritonei. Genomic analysis detected KRAS (G12D), GNAS (R201C), and FBXW7 (R367*) variants in the primary tumor. In addition, the tumor showed aneuploidy with loss of heterozygosity (LOH) in all its chromosomes, which suggested that the primary ovarian tumor was derived from germ cells. Existence of one Barr body suggested the existence of uniparental disomy of the tumors throughout the genome, instead of a haploid genotype. All three pathogenic variants remained positive in the initial recurrent tumor, as well as in the paired DNA from the whole blood in pseudomyxoma peritonei. The pathogenic variant of KRAS (G12D) was also identified in the autopsy specimen of the appendix by droplet digital polymerase chain reaction.ConclusionsThis study pathologically and genetically confirmed that the primary ovarian borderline tumor was derived from the intestinal component of an ovarian teratoma, and that the subsequent pseudomyxoma peritonei progressed from the primary ovarian tumor. Integrative genomic analysis was useful to identify cellular origin of tumors, as well as to precisely interpret the process of disease progression.

The neo-X does not form a Barr body but shows a slightly condensed structure in the Okinawa spiny rat (Tokudaia muenninki).

X chromosome inactivation (XCI) is an essential mechanism for gene dosage compensation between male and female cells in mammals. The Okinawa spiny rat (Tokudaia muenninki) is a native rodent in Japan with XX/XY sex chromosomes, like most mammals; however, the X chromosome has acquired a neo-X region (Xp) by fusion with an autosome. We previously reported that dosage compensation has not yet evolved in the neo-X region; however, X-inactive-specific transcript (Xist) RNA (long non-coding RNA required for the initiation of XCI) is partially localized in the region. Here, we show that the neo-X region represents an early chromosomal state in the acquisition of XCI by analyses of heterochromatin and Barr body formation. We found no evidence for heterochromatin formation in the neo-X region by RBA (R-banding by acridine orange) assays and immunostaining of H3K27me3. Double-immunostaining of H3K27me3 and HP1, a component of the Barr body, revealed that the entire ancestral-X chromosome region (Xq) showed a bipartite folded structure. By contrast, HP1 was not localized to the neo-X region. However, BAC FISH revealed that the signals of genes on the neo-X region of the inactive X chromosome were concentrated in a narrow region. These findings indicated that although the neo-X region of the inactive X chromosome does not form a complete Barr body structure (e.g., it lacks HP1), it forms a slightly condensed structure. These findings combined with the previously reported partial binding of Xist RNA suggest that the neo-X region exhibits incomplete inactivation. This may represent an early chromosomal state in the acquisition of the XCI mechanism.

Nuclear Organization in Response to Stress: A Special Focus on Nucleoli.

In this chapter, we discuss the nuclear organization and how it responds to different types of stress. A key component in these responses is molecular traffic between the different sub-nucleolar compartments, such as nucleoplasm, chromatin, nucleoli, and various speckle and body compartments. This allows specific repair and response activities in locations where they normally are not active and serve to halt sensitive functions until the stress insult passes and inflicted damage has been repaired. We focus on mammalian cells and their nuclear organization, especially describing the central role of the nucleolus in nuclear stress responses. We describe events after multiple stress types, including DNA damage, various drugs, and toxic compounds, and discuss the involvement of macromolecular traffic between dynamic, phase-separated nuclear organelles and foci. We delineate the key proteins and non-coding RNA in the formation of stress-responsive, non-membranous nuclear organelles, many of which are relevant to the formation of and utilization in cancer treatment.

A STUDY OF BARR BODIES IN CASES OF PRIMARY AMENORRHEA.

BACKGROUND: Barr body (or) X- chromatin is a heterochromatin mass seen in all somatic cells of females species. They account to nearly 80-90% in females and 1-3% of cells of normal males. Primary Amenorrhea a clinical condition is of varied aetiology, however Genetic factors being the major cause. Either a structural or a numerical anomaly like X- monosomy of a female results in failure of commencement of menstruation. Identication of chromatin negative condition in patients of primary amenorrhoea constitutes my study. The study i METHODOLOGY: s conducted on 58 patients who visited Obstetrics Gynaecology clinics Visakhapatnam district with presenting complaint of primary amenorrhea. Buccal smear examination is done to all the patients and observed under the microscope for Barr bodies. Photographs were taken and the observations were tabulated and analysed. Absence of Barr Body was ob RESULTS: served in 28 cases (chromatin negative) and 26 cases were chromatin positive and 4 cases showed mosaicism. Primary CONCLUSION: Amenorrhea due to chromosomal aberrations is a serious condition as it is associated with intense psychological trauma along with physical. In Turner's syndrome single X-chromosome is present (45XO), the subject is female in phenotype, but the ovaries are rudimentary (Streak Gonads) and absence of development of secondary sexual characters. So buccal smear is a simple, rapid test that will enable us to decide which patients are to be referred for further investigations to conrm the diagnosis.

Comparative Test on the Bond Damage of Steel and GFRP Bars Reinforcing Soft Rock Slopes

Soft rock slopes were anchored with traditional steel bars and new Glass Fibre Reinforced Polymer (GFRP) bars. The difference in the anchorage performance of the two kinds of anchorage elements in soft rock and expansive soil was studied by an in-situ test. The results show that cyclic load can aggravate the bond damage of the interface between grouting body and both kinds of bars used in soft rock. Compared with the number of cyclic loads applied, the previous maximum load is the main factor that influences the bond damage of the anchorage bar. Under constant loading, the interface bond behaviour of GFRP bar is better than the steel bar. Because of the small difference in elastic modulus between the GFRP bar and the grouting body, the interface bond around the GFRP bar can invoke more resistance of the grouting body efficiently which demonstrates its more effective anchorage performance than the steel bar under the same conditions. The anchorage structure of steel bar in soft rock can generate larger interfacial relative displacement with increasing load than the GFRP bar in the anchorage section, even though the elastic modulus of steel is much larger than GFRP. In the expansive soil, the anchorage structure deformations of steel and GFRP bars are almost the same because of the weaker bond at the interface of the grouting body and the surrounding soil than that of the bar interface. Under the ultimate loading of the anchorage structure in soft rock, the steel bar with 450 MPa which is less than its ultimate strength shows the failure of the bar body pulling-out, and the GFRP bar with 508 MPa which is larger than its ultimate strength shows the failure of the bar body by fracture. The steel bar anchorage structure in soft rock is destroyed at the interface around the grouting body. The results show that the GFRP bar performs more efficiently than the steel bar.

Re-Envisioning the History of Cellular and Molecular Biology

Re-Envisioning the History of Cellular and Molecular Biology

Uncovering the Principles of Genome Folding by 3D Chromatin Modeling.

Our understanding of how genomic DNA is tightly packed inside the nucleus, yet is still accessible for vital cellular processes, has grown dramatically over recent years with advances in microscopy and genomics technologies. Computational methods have played a pivotal role in the structural interpretation of experimental data, which helped unravel some organizational principles of genome folding. Here, we give an overview of current computational efforts in mechanistic and data-driven 3D chromatin structure modeling. We discuss strengths and limitations of different methods and evaluate the added value and benefits of computational approaches to infer the 3D structural and dynamic properties of the genome and its underlying mechanisms at different scales and resolution, ranging from the dynamic formation of chromatin loops and topological associated domains to nuclear compartmentalization of chromatin and nuclear bodies.

The B-cell Receptor Autoantigen LRPAP1 Can Replace Variable Antibody Regions to Target Mantle Cell Lymphoma Cells.

Mantle cell lymphoma (MCL) accounts for 5%–10% of all lymphomas. The disease’s genetic hallmark is the t(11; 14)(q13; q32) translocation. In younger patients, the first-line treatment is chemoimmunotherapy followed by autologous stem cell transplantation. Upon disease progression, novel and targeted agents such as the BTK inhibitor ibrutinib, the BCL-2 inhibitor venetoclax, or the combination of both are increasingly used, but even after allogeneic stem cell transplantation or CAR T-cell therapy, MCL remains incurable for most patients. Chronic antigenic stimulation of the B-cell receptor (BCR) is thought to be essential for the pathogenesis of many B-cell lymphomas. LRPAP1 has been identified as the autoantigenic BCR target in about 1/3 of all MCLs. Thus, LRPAP1 could be used to target MCL cells, however, there is currently no optimal therapeutic format to integrate LRPAP1. We have therefore integrated LRPAP1 into a concept termed BAR, for B-cell receptor antigens for reverse targeting. A bispecific BAR body was synthesized consisting of the lymphoma-BCR binding epitope of LRPAP1 and a single chain fragment targeting CD3 or CD16 to recruit/engage T or NK cells. In addition, a BAR body consisting of an IgG1 antibody and the lymphoma-BCR binding epitope of LRPAP1 replacing the variable regions was synthesized. Both BAR bodies mediated highly specific cytotoxic effects against MCL cells in a dose-dependent manner at 1–20 µg/mL. In conclusion, LRPAP1 can substitute variable antibody regions in different formats to function in a new therapeutic approach to treat MCL.

Goose Nephritic Astrovirus Infection of Goslings Induces Lymphocyte Apoptosis, Reticular Fiber Destruction, and CD8 T-Cell Depletion in Spleen Tissue.

The emergence of a novel goose nephritic astrovirus (GNAstV) has caused economic losses to the Chinese goose industry. High viral load is found in the spleen of goslings infected with GNAstV, but pathological injuries to the spleen due to GNAstV are largely unknown. In this study, 50 two-day-old goslings were infected orally with GNAstV, and 50 goslings were treated with PBS as control. Spleens were collected at different times following infection to assess damage. GNAstV infection caused visceral gout and urate deposition in joints, and resulted in 16% mortality. GNAstV was found in the lymphocytes and macrophages within the spleen. Lymphocyte loss, especially around the white pulp, and destruction and decline in the number of reticular fibers was observed in GNAstV-infected goslings. Moreover, in GNAstV-infected goslings, ultrahistopathological examination found that splenic lymphocytes exhibited condensed chromatin and apoptotic bodies, and reticular cells displayed damage to plasma membrane integrity and swollen mitochondria. Furthermore, TUNEL staining confirmed apoptosis of lymphocytes, and the mRNA levels of Fas and FasL were significantly increased in the GNAstV-infected goslings. In addition, GNAstV infection reduced the number and protein expression of CD8. In conclusion, GNAstV infection causes lymphocyte depletion, reticular cell necrosis, reticular fiber destruction, lymphocyte apoptosis, and reduction in CD8 levels, which contribute to spleen injury.

Distinguishing mid‐channel and bank‐attached fluvial bars by flow divergence: Implications for the interpretation of stratigraphic records

AbstractThe characterization of ancient fluvial‐channel bars informs predictions of sedimentary facies distribution, and hence they are critical for interpreting river morphodynamics through time. Within active fluvial channels, sediment storage occurs along the banks or along their axial portion, generating bank‐attached or mid‐channel bars, respectively. This study introduces the angle of flow divergence (Δf), measured as the angle between the azimuths of bar accretionary slopes and local dune migration, and quantitatively explores its distribution in 103 channel reaches that have a sandy bed load and clear water. This dataset includes both mid‐channel and bank‐attached bars from low‐variable peak discharge rivers of Russia and Brazil. Remotely sensed evidence shows that dune migration transverse to the dip azimuth of bar slopes (Δf 90–110°) occurs both in mid‐channel and bank‐attached bars, contradicting the long‐standing tenet that palaeoflows nearly orthogonal to the dip azimuth of large‐scale inclined strata are indicative of sinuous, single‐thread palaeochannels. Only Δf values significantly higher (&gt;140°) or lower (&lt;60°) than 90° discriminate mid‐channel and bank‐attached fluvial bars. Comparisons between Δf values and bar‐accretionary styles suggest that mid‐channel bars formed by high‐peak and low‐peak variable discharge rivers tend to preserve axially and laterally accreting deposits, respectively. Nearly orthogonal divergence angles are found in bank‐attached bars irrespective of peak‐discharge variability. While stressing that analyses akin to the one presented here are to be complemented with additional sedimentological information from high‐quality outcrops, this study proposes a new, quantitative, approach to better distinguish fluvial bars, and hence possibly the planform pattern of associated channel bodies, from sedimentary successions. In particular, the data show that a reliable distinction between mid‐channel and bank‐attached bars should be based on comprehensive palaeocurrent and architectural information from various portions of preserved bar bodies, and that inferences based on limited datasets should be considered with caution.

COMPARATIVE STUDY OF EFFICACY OF PAPANICOLAOU AND ACETO-ORCEIN STAINS IN DEMONSTRATING BARR BODIES IN BUCCAL MUCOSAL SMEARS

Introduction: Establishing one’s sexual identity has a critical role in medical conditions like ambiguous genitalia and in crime investigations. There are various investigations to determine the sexual identity of a person and Barr body evaluation in buccal smears forms the first line of investigation. Barr body estimation in buccal mucosal scrapes has been demonstrated by using different stains like Papanicolaou, Aceto-Orcein(AO), Feulgen, Guard, Cresyl violet, Carbol fuchsin and fluorescent staining methods, but with varying efficacy. &#x0D; The current study is done to evaluate the efficacy of Papanicolaou and AO stains in demonstration of Barr bodies.&#x0D; Materials and Methods: A total of 207 medical students were included in the study. Two buccal smears were collected from each student and subsequently, one was stained with Aceto-Orcein by squash technique and the other with Papanicolaou stain. Both slides were evaluated for percentage of Barr bodies using 1000x magnification and cytomorphological features in 400x.&#x0D; Results: The percentage of Barr bodies in AO stained slides ranged from 5-18 among females and 0-8 in males, while with Papanicolaou stain the ranges recorded were 4 – 12 in females,&#x0D; 0 – 2 in males. The accuracy of AO and Papanicolaou stains for detecting sex accurately were 97% and 91% respectively. Evaluation of the buccal smears was better in AO stained smears because of the clean background and better cytoplasmic and nuclear contrast in comparison to PAP stain.&#x0D; Conclusion: Aceto-Orcein staining method is rapid, economical, accurate, reproducible and comparable to Papanicolaou staining, for the detection of Barr body in buccal mucosal smears.&#x0D; Keywords: Aceto-Orcein, Papanicolaou, Buccal smears, Barr body.

Packaging of Subchromosomal-Size DNA Molecules in Chromatin Bodies in the Ciliate Macronucleus

A fundamental difference between somatic nuclei (macronuclei) of ciliates and cell nuclei of higher eukaryotes is that the macronuclear genome is a huge number (up to tens or hundreds of thousands) of gene-sized (0.5-25 kb) or subchromosomal (up to 2000 kb) minichromosomes. Electron microscopy shows that macronuclear chromatin usually looks like chromatin bodies or fibrils 200-300 nm thick in the interphase. However, the question of how many DNA molecules are contained in an individual chromatin body remains open. The organization of chromatin in macronuclei was studied in the ciliates Didinium nasutum and three Paramecium sp, which differ in pulsed-field gel electrophoresis (PFGE) karyotype, and compared with the model of topologically associated domains (TADs) of higher eukaryotic nuclei. PFGE showed that the sizes of macronuclear DNAs ranged from 50 to 1700 kb, while the majority of the molecules were less than 500 kb in length. A comparative quantitative analysis of the PFGE and electron microscopic data showed that each chromatin body contained one minichromosome in P. multimicronucleatum in the logarithmic growth phase, while bodies in the D. nasutum macronucleus contained two or more DNA molecules each. Chromatin bodies aggregated during starvation, when activity of the macronuclei decreased, leading to an increase of chromatin body size or the formation of 200- to 300-nm fibrils of several chromatin bodies. A model was proposed to explain the formation of such structures. In terms of topological characteristics, macronuclear chromatin bodies with subchromosomal DNA molecules were found to correspond to higher eukaryotic TADs.

Formation of a multi-layered 3-dimensional structure of the heterochromatin compartment during early mammalian development.

During embryogenesis in mammals, the 3-dimensional (3D) genome organization changes globally in parallel with transcription changes in a cell-type specific manner. This involves the progressive formation of heterochromatin, the best example of which is the inactive X chromosome (Xi) in females, originally discovered as a compact 3D structure at the nuclear periphery known as the Barr body. The heterochromatin formation on the autosomes and the Xi is tightly associated with the differentiation state and the developmental potential of cells, making it an ideal readout of the cellular epigenetic state. At a glance, the heterochromatin appears to be uniform. However, recent studies are beginning to reveal a more complex picture, with multiple hierarchical levels co-existing within the heterochromatin compartment. Such hierarchical levels appear to exist in the heterochromatin compartment on autosomes as well as on the Xi. Here, we review recent progress in our understanding of the 3D genome organization changes during the period of differentiation surrounding pluripotency in vivo and in vitro, with a focus on the heterochromatin compartment. We first look at the whole genome, then focus on the Xi, and discuss their differences and similarities. Finally, we present a unified view of how the heterochromatin compartment is formed and regulated during early development. In particular, we emphasize that there are multiple layers within the heterochromatic compartment on both the autosomes and the Xi, with regulatory mechanisms common and specific to each layer.

Skewed Inactivation of X Chromosome: A Cause of Hemophilia Manifestation in Carrier Females.

Hemophilia is an X-linked recessive hereditary disorder that classically affects males due to the presence of only one X chromosome in males. Females are usually carriers due to the presence of counterpart X chromosome, but many times manifestations of hemophilia are seen in heterozygous carrier females. This is a result of skewed lionization, in which more normal X chromosomes are converted to bar body, and more abnormal chromosomes remain active in body cells, causing the dominant manifestation of the disease. The severity of manifestations is directly proportional to the level of the clotting factor in the blood. The disease can be severe enough to cause life-threatening bleeding, especially during delivery. Physicians usually reluctant to assume hemophilia in the differential diagnosis of the bleeding disorders in women but manifesting carrier females with hemophilia are not uncommon. Our review of the literature will give an opportunity to understand this issue more precisely as well as will discuss the disease manifestations and its updated management.

Improve Awareness of the Forensic Odontology among Medical Graduates: Need of the Hour?

Introduction: Forensic odontology is a fastly growing field in both dental and forensic sciences. It involves the application of principles and expertise of dental sciences for criminal investigations. With increasing demand and use of dental evidence in forensic examinations, proper knowledge and awareness of the subject is more necessary than ever before. Materials and Method: A survey was conducted in Medical and Dental colleges in and around Mangalore, Dakshina Kannada after approval from institutional ethics committee. It included MBBS and BDS students (III year to internship) Result: The analysis of the data showed two fold results. Knowledge of tooth as a source of DNA, evidence for natural disasters in personalle identification was equal among the graduates. Medical graduates had higher awarenes of certain aspects like barr bodies and anthropometry whereas; Dental graduates were aware of the odontology aspects in identification of cases of rapes, child abuse, techniques like forensic radiology, bite mark analysis and sexual dimorphism in teeth. Conclusion: The study highlighted the difference in knowledge of forensic odontology between medical and dental students. It emphasized on the need of increasing awareness of the subject among medical graduates and to help them understand the role of their peers from the dental fraternity in forensic sciences. The study also stressed on the need of a forensic odontologist in the State Forensic Team.