105 research outputs found

    Mouse Gestation Length Is Genetically Determined

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    Background: Preterm birth is an enormous public health problem, affecting over 12 % of live births and costing over $26 billion in the United States alone. The causes are complex, but twin studies support the role of genetics in determining gestation length. Despite widespread use of the mouse in studies of the genetics of preterm birth, there have been few studies that actually address the precise natural gestation length of the mouse, and to what degree the timing of labor and birth is genetically determined. Methodology/Principal Findings: To further develop the mouse as a genetic model of preterm birth, we developed a highthroughput monitoring system and measured the gestation length in 15 inbred strains. Our results show an unexpectedly wide variation in overall gestation length between strains that approaches two full days, while intra-strain variation is quite low. Although litter size shows a strong inverse correlation with gestation length, genetic difference alone accounts for a significant portion of the variation. In addition, ovarian transplant experiments support a primary role of maternal genetics in the determination of gestation length. Preliminary analysis of gestation length in the C57BL/6J-Chr # A/J /NaJ chromosome substitution strain (B.A CSS) panel suggests complex genetic control of gestation length. Conclusions/Significance: Together, these data support the role of genetics in regulating gestation length and present th

    Superior olivary complex organization and cytoarchitecture may be correlated with function and catarrhine primate phylogeny

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    In the mammalian auditory system, the medial nucleus of the trapezoid body and the lateral superior olive (MNTB-LSO system) contribute to binaural intensity processing and lateralization. Localization precision varies with the sound frequencies. As recency of common ancestry with human beings increases, primates have improved low-frequency sensitivity and reduced sensitivity to higher frequencies. The medial part of the MNTB is devoted to higher frequency processing. Thus, its high-frequency-dependent function is nearly lost in humans and its role in binaural processing as part of the contralateral pathway to the LSO remains questionable. Here, Nissl-stained sections of the superior olivary complex of man (Homo sapiens), bonobo (Pan paniscus), chimpanzee (Pan troglodytes), gorilla (Gorilla gorilla), orangutan (Pongo pygmaeus), gibbon (Hylobates lar), and macaque (Macaca fascicularis) were compared to reveal differences and coincidences. From chimpanzees to humans, the size of the LSO decreased, and the MNTB as a compact nucleus nearly disappears. From chimpanzees to humans, the LSO/MNTB ratio increases dramatically too, whereas the LSO/MSO ratio remains 1.1; a finding that probably corresponds to the phylogenetic proximity between the species

    Evidence of Key Tinnitus-Related Brain Regions Documented by a Unique Combination of Manganese-Enhanced MRI and Acoustic Startle Reflex Testing

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    Animal models continue to improve our understanding of tinnitus pathogenesis and aid in development of new treatments. However, there are no diagnostic biomarkers for tinnitus-related pathophysiology for use in awake, freely moving animals. To address this disparity, two complementary methods were combined to examine reliable tinnitus models (rats repeatedly administered salicylate or exposed to a single noise event): inhibition of acoustic startle and manganese-enhanced MRI. Salicylate-induced tinnitus resulted in wide spread supernormal manganese uptake compared to noise-induced tinnitus. Neither model demonstrated significant differences in the auditory cortex. Only in the dorsal cortex of the inferior colliculus (DCIC) did both models exhibit supernormal uptake. Therefore, abnormal membrane depolarization in the DCIC appears to be important in tinnitus-mediated activity. Our results provide the foundation for future studies correlating the severity and longevity of tinnitus with hearing loss and neuronal activity in specific brain regions and tools for evaluating treatment efficacy across paradigms

    Hamartomas, teratomas and teratocarcinosarcomas of the head and neck: Report of 3 new cases with clinico-pathologic correlation, cytogenetic analysis, and review of the literature

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    <p>Abstract</p> <p>Background</p> <p>Germ-cell tumors (GCT) are a histologically and biologically diverse group of neoplasms which primarily occur in the gonads but also develop at different extragonadal sites in the midline of the body. The head and neck region including the upper respiratory tract is a very rare location for such tumors in both children and adults, which can cause diagnostic and therapeutic difficulties.</p> <p>Methods</p> <p>We describe here two new cases of multilineage tumors including sinonasal teratocarcinosarcoma [SNTCS], and congenital oronasopharyngeal teratoma (epignathus) and compare their features with those of a new case of a rare salivary gland anlage tumor [SGAT], an entity for which the pathogenesis is unclear (i.e. hamartoma versus neoplasm). We correlate their presenting clinico-pathological features and compare histologic and cytogenetic features in an attempt to elucidate their pathogenesis and biologic potentials.</p> <p>Results and discussion</p> <p>Cytogenetic analysis revealed chromosomal abnormalities only in the case of SNTCS that showed trisomy 12 and 1p deletion. Both cytogenetic abnormalities are characteristically present in malignant germ cell tumors providing for the first time evidence that this rare tumor type indeed might represent a variant of a germ cell neoplasm. The SGAT and epignathus carried no such cytogenetic abnormalities, in keeping with their limited and benign biologic potential.</p> <p>Conclusion</p> <p>The comparison of these three cases should serve to emphasize the diversity of multilineage tumors (hamartomas and GCT) of the upper respiratory tract in regards to their biology, age of presentation and clinical outcomes. Malignant tumors of germ cell origins are more likely to affect adults with insidious symptom development, while benign tumors can nevertheless cause dramatic clinical symptoms which, under certain circumstances, can be fatal.</p

    Carbocyanine Dye Usage in Demarcating Boundaries of the Aged Human Red Nucleus

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    Background: Though the adult human magnocellular Red nucleus (mNr) is essentially vestigial and its boundaries with neighbouring structures have never been well demarcated, human studies in utero have shown a well developed semilunar mNr wrapping around the caudal parvicellular Red nucleus (pNr), similar to what is seen in quadrupeds. In the present study, we have sought to better delineate the morphological determinants of the adult human Red nucleus (ahRn). Methods and Findings: Serial sections of ahRn show fine myelinated fibers arising from pNr and turning toward the central tegmental tract. DiI was deposited within a well restricted region of ahRn at the fasciculus retroflexus level and the extent of label determined. Nissl-stained serial sections allowed production of a 3-D mNr model, showing rudimentary, vestigial morphology compared with its well developed infant homologue. DiI within this vestigial mNr region at the level of the oculomotor nerve showed labeled giant/large mNr neurons, coarse fiber bundles at the ventral tegmental decussation and lateral lemniscal label. Conclusions: Large amounts of DiI and a long incubation time have proven useful in aged human brain as a marker of long axons and large cell bodies of projecting neurons such as the rubrospinal projection and for clarifying nuclear boundaries of closed nuclei (e.g., the large human pNr). Our 3D model of adult human mNr appeared shrunken in shape and axiall

    The protein phosphatase 1 regulator NIPP1 is essential for mammalian spermatogenesis

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    NIPP1 is one of the major nuclear interactors of protein phosphatase PP1. The deletion of NIPP1 in mice is early embryonic lethal, which has precluded functional studies in adult tissues. Hence, we have generated an inducible NIPP1 knockout model using a tamoxifen-inducible Cre recombinase transgene. The inactivation of the NIPP1 encoding alleles (Ppp1r8) in adult mice occurred very efficiently in testis and resulted in a gradual loss of germ cells, culminating in a Sertoli-cell only phenotype. Before the overt development of this phenotype Ppp1r8 -/- testis showed a decreased proliferation and survival capacity of cells of the spermatogenic lineage. A reduced proliferation was also detected after the tamoxifen-induced removal of NIPP1 from cultured testis slices and isolated germ cells enriched for undifferentiated spermatogonia, hinting at a testis-intrinsic defect. Consistent with the observed phenotype, RNA sequencing identified changes in the transcript levels of cell-cycle and apoptosis regulating genes in NIPP1-depleted testis. We conclude that NIPP1 is essential for mammalian spermatogenesis because it is indispensable for the proliferation and survival of progenitor germ cells, including (un)differentiated spermatogonia.publishe

    Developing and pre-testing a decision board to facilitate informed choice about delivery approach in uncomplicated pregnancy

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    <p>Abstract</p> <p>Background</p> <p>The rate of caesarean sections is increasing worldwide, yet medical literature informing women with uncomplicated pregnancies about relative risks and benefits of elective caesarean section (CS) compared with vaginal delivery (VD) remains scarce. A decision board may address this gap, providing systematic evidence-based information so that patients can more fully understand their treatment options. The objective of our study was to design and pre-test a decision board to guide clinical discussions and enhance informed decision-making related to delivery approach (CS or VD) in uncomplicated pregnancy.</p> <p>Methods</p> <p>Development of the decision board involved two preliminary studies to determine women's preferred mode of risk presentation and a systematic literature review for the most comprehensive presentation of medical risks at the time (VD and CS). Forty women were recruited to pre-test the tool. Eligible subjects were of childbearing age (18-40 years) but were not pregnant in order to avoid raising the expectation among pregnant women that CS was a universally available birth option. Women selected their preferred delivery approach and completed the Decisional Conflict Scale to measure decisional uncertainty before and after reviewing the decision board. They also answered open-ended questions reflecting what they had learned, whether or not the information had helped them to choose between birth methods, and additional information that should be included. Descriptive statistics were used to analyse sample characteristics and women's choice of delivery approach pre/post decision board. Change in decisional conflict was measured using Wilcoxon's sign rank test for each of the three subscales.</p> <p>Results</p> <p>The majority of women reported that they had learned something new (n = 37, 92%) and that the tool had helped them make a hypothetical choice between delivery approaches (n = 34, 85%). Women wanted more information about neonatal risks and personal experiences. Decisional uncertainty decreased (p < 0.001) and perceived effectiveness of decisions increased (p < 0.001) post-intervention.</p> <p>Conclusion</p> <p>Non-pregnant women of childbearing age were positive about the decision board and stated their hypothetical delivery choices were informed by risk presentation, but wanted additional information about benefits and experiences. This study represents a preliminary but integral step towards ensuring women considering delivery approaches in uncomplicated pregnancies are fully informed.</p

    Malignant mesothelioma

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    Malignant mesothelioma is a fatal asbestos-associated malignancy originating from the lining cells (mesothelium) of the pleural and peritoneal cavities, as well as the pericardium and the tunica vaginalis. The exact prevalence is unknown but it is estimated that mesotheliomas represent less than 1% of all cancers. Its incidence is increasing, with an expected peak in the next 10–20 years. Pleural malignant mesothelioma is the most common form of mesothelioma. Typical presenting features are those of chest pain and dyspnoea. Breathlessness due to a pleural effusion without chest pain is reported in about 30% of patients. A chest wall mass, weight loss, sweating, abdominal pain and ascites (due to peritoneal involvement) are less common presentations. Mesothelioma is directly attributable to occupational asbestos exposure with a history of exposure in over 90% of cases. There is also evidence that mesothelioma may result from both para-occupational exposure and non-occupational "environmental" exposure. Idiopathic or spontaneous mesothelioma can also occur in the absence of any exposure to asbestos, with a spontaneous rate in humans of around one per million. A combination of accurate exposure history, along with examination radiology and pathology are essential to make the diagnosis. Distinguishing malignant from benign pleural disease can be challenging. The most helpful CT findings suggesting malignant pleural disease are 1) a circumferential pleural rind, 2) nodular pleural thickening, 3) pleural thickening of > 1 cm and 4) mediastinal pleural involvement. Involvement of a multidisciplinary team is recommended to ensure prompt and appropriate management, using a framework of radiotherapy, chemotherapy, surgery and symptom palliation with end of life care. Compensation issues must also be considered. Life expectancy in malignant mesothelioma is poor, with a median survival of about one year following diagnosis
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