403 research outputs found
Bounding W-W' mixing with spin asymmetries at RHIC
The W boson can obtain a small right-handed coupling to quarks and leptons through mixing with a hypothetical
Comparing the Experiences and Withdrawal Considerations of Treatment and Regular Foster Care Parents: The Canadian Perspective
This study investigated differences in the experiences of Canadian foster parents providing regular and treatment foster care and their consideration to withdraw from their position. Survey responses from 852 foster parents were analyzed subsequent to separating the participants into two groups based on the primary type of care they provided (regular N = 454; treatment N = 398). Results revealed that treatment foster care parents considered withdrawing at a higher rate compared to regular foster care parents. Subsequent analysis revealed numerous differences between the two groups regarding foster parents’ experiences in fostering and reasons to withdraw. The results are discussed in the context of increasing concern for a declining number of foster parents with the coincidental increase in the number of children who enter foster care with higher rates of trauma and mental health disorders requiring a treatment response
The Influence of a Fibrin-Coating Inside a Biodegradable Poly(DL-Lactide-ε-Caprolactone) Nerve Guide on Peripheral Nerve Regeneration
The aim of this study was to evaluate the effect of a fibrin-coating on the inner surface of a biodegradable poly(DL-lactide-E-caprolactone) nerve guide on the speed and quality of the nerve regeneration. The nerve regeneration and orientation of the nerve fibers, as well as the fibrous tissue formation were evaluated. On the short term, nerve regeneration was slightly faster in the non-coated nerve guide. After longer implantation periods (≥ 4 weeks), nerve regeneration in the fibrin-coated nerve guides was characterized by a severe inflammatory response with large numbers of macrophages and polymorphonuclear cells (PMN\u27s). This study clearly demonstrates that nerve regeneration in a fibrin-coated nerve guide is not faster when compared with a non-coated nerve guide, and that nerve regeneration in the fibrin-coated nerve guide is even worse after longer implantation periods
Primary Cauda Equina T-Cell Lymphoblastic Lymphoma
BACKGROUND: T-cell lymphoblastic lymphoma (T-LBL) is a rare and aggressive form of non-Hodgkin lymphoma. This report describes, to our knowledge, the first adult case of a primary cauda equina T-LBL. Treatment consists of multiagent chemotherapy, and surgical removal of T-LBL does not improve outcome. We discuss the workup of patients with an intradural spinal mass, together with a review of the literature on primary spinal lymphoma of the cauda equina. CASE DESCRIPTION: A 54-year-old woman with Crohn's disease, for which she was taking immunosuppressive medication, presented with progressive back pain radiating to both legs and deteriorating neurologic deficits caused by an intradural, contrast-enhancing lesion in the L1-5 region. During acute surgery, the tumor was partially resected. Immunohistochemical phenotyping revealed a T-LBL. No other lymphoma localizations were found after subsequent staging. Despite extensive treatment, the patient died of disseminated disease throughout the central nervous system, 6 weeks after the diagnosis. CONCLUSIONS: Pain and progressive neurologic complaints can be symptoms of a (malignant) intradural spinal tumor. Intradural lymphoma must be considered as a differential diagnosis by clinicians because it can mimic neoplasms that often require urgent surgery. The histopathologic diagnosis should preferably be obtained by way of cerebrospinal fluid analysis or tumor biopsy because tumor resection has no beneficial effect on the oncologic outcome
An aggressive poorly differentiated plurihormonal Pit-1-positive adenoma
In July 2017, a 35-year-old woman was referred to our care for treatment of a large pituitary mass with an unusually high growth rate. She presented with right-sided ptosis and diplopia (n. III palsy), increasing retrobulbar pain and vertigo. Although laboratory investigations were consistent with acromegaly, she exhibited no clear phenotypic traits. During transsphenoidal surgery aimed at biopsy, typical adenomatous tissue was encountered, upon which it was decided to proceed to debulking. Histopathological analysis demonstrated a poorly differentiated plurihormonal Pit-1-positive adenoma with focal growth hormone (GH) and prolactin positivity, positive SSTR2 staining and a Ki-67 of 20–30%. Postoperative magnetic resonance imaging (MRI) examination revealed a large tumour remnant within the sella invading the right cavernous sinus with total encasement of the internal carotid artery and displacement of the right temporal lobe. As a consequence, she was treated additionally with radiotherapy, and a long-acting first-generation somatostatin analogue was prescribed. Subsequently, the patient developed secondary hypocortisolism and diabetes mellitus despite adequate suppression of GH levels. In September 2019, her symptoms recurred. Laboratory evaluations indicated a notable loss of biochemical control, and MRI revealed tumour progression. Lanreotide was switched to pasireotide, and successful removal of the tumour remnant and decompression of the right optic nerve was performed. She received adjuvant treatment with temozolomide resulting in excellent biochemical and radiological response after three and six courses. Symptoms of right-sided ptosis and diplopia remained. Evidence for systemic therapy in case of tumour progression after temozolomide is currently limited, although various potential targets can be identified in tumour tissue
Large scale single nucleotide polymorphism discovery in unsequenced genomes using second generation high throughput sequencing technology: applied to turkey
<p>Abstract</p> <p>Background</p> <p>The development of second generation sequencing methods has enabled large scale DNA variation studies at moderate cost. For the high throughput discovery of single nucleotide polymorphisms (SNPs) in species lacking a sequenced reference genome, we set-up an analysis pipeline based on a short read de novo sequence assembler and a program designed to identify variation within short reads. To illustrate the potential of this technique, we present the results obtained with a randomly sheared, enzymatically generated, 2-3 kbp genome fraction of six pooled <it>Meleagris gallopavo </it>(turkey) individuals.</p> <p>Results</p> <p>A total of 100 million 36 bp reads were generated, representing approximately 5-6% (~62 Mbp) of the turkey genome, with an estimated sequence depth of 58. Reads consisting of bases called with less than 1% error probability were selected and assembled into contigs. Subsequently, high throughput discovery of nucleotide variation was performed using sequences with more than 90% reliability by using the assembled contigs that were 50 bp or longer as the reference sequence. We identified more than 7,500 SNPs with a high probability of representing true nucleotide variation in turkeys. Increasing the reference genome by adding publicly available turkey BAC-end sequences increased the number of SNPs to over 11,000. A comparison with the sequenced chicken genome indicated that the assembled turkey contigs were distributed uniformly across the turkey genome. Genotyping of a representative sample of 340 SNPs resulted in a SNP conversion rate of 95%. The correlation of the minor allele count (MAC) and observed minor allele frequency (MAF) for the validated SNPs was 0.69.</p> <p>Conclusion</p> <p>We provide an efficient and cost-effective approach for the identification of thousands of high quality SNPs in species currently lacking a sequenced genome and applied this to turkey. The methodology addresses a random fraction of the genome, resulting in an even distribution of SNPs across the targeted genome.</p
Neurofibromatosis type 1 associated low grade gliomas:A comparison with sporadic low grade gliomas
AbstractNeurofibromatosis type 1 (NF1) is an autosomal dominant disorder, associated with a variable clinical phenotype including café-au-lait spots, intertriginous freckling, Lisch nodules, neurofibromas, optic pathway gliomas and distinctive bony lesions. NF1 is caused by a mutation in the NF1 gene, which codes for neurofibromin, a large protein involved in the MAPK- and the mTOR-pathway through RAS-RAF signalling.NF1 is a known tumour predisposition syndrome, associated with different tumours of the nervous system including low grade gliomas (LGGs) in the paediatric population. The focus of this review is on grade I pilocytic astrocytomas (PAs), the most commonly observed histologic subtype of low grade gliomas in NF1. Clinically, these PAs have a better prognosis and show different localisation patterns than their sporadic counterparts, which are most commonly associated with a KIAA1549:BRAF fusion.In this review, possible mechanisms of tumourigenesis in LGGs with and without NF1 will be discussed, including the contribution of different signalling pathways and tumour microenvironment. Furthermore we will discuss how increased understanding of tumourigenesis may lead to new potential targets for treatment
Dynamic orifice area variations in functional mitral regurgitation: In vivoreproduction and mechanistic insights
Aims: The spinocerebellar ataxia type 2 (SCA2), type 3 (SCA3) and type 7 (SCA7) are clinically characterized by progressive and severe ataxic symptoms, dysarthria, dysphagia, oculomotor impairments, pyramidal and extrapyramidal manifestations and sensory deficits. Although recent clinical studies reported additional disease signs suggesting involvement of the brainstem auditory system, this has never been studied in detail in SCA2, SCA3 or SCA7. Methods: We performed a detailed pathoanatomical investigation of unconventionally thick tissue sections through the auditory brainstem nuclei (that is, nucleus of the inferior colliculus, nuclei of the lateral lemniscus, superior olive, cochlear nuclei) and auditory brainstem fibre tracts (that is, lateral lemniscus, trapezoid body, dorsal acoustic stria, cochlear portion of the vestibulocochlear nerve) of clinically diagnosed and genetically confirmed SCA2, SCA3 and SCA7 patients. Results: Examination of unconventionally thick serial brainstem sections stained for lipofuscin pigment and Nissl material revealed a consistent and widespread involvement of the auditory brainstem nuclei in the SCA2, SCA3 and SCA7 patients studied. Serial brainstem tissue sections stained for myelin showed loss of myelinated fibres in two of the auditory brainstem fibre tracts (that is, lateral lemniscus, trapezoid body) in a subset of patients. Conclusions: The involvement of the auditory brainstem system offers plausible explanations for the auditory impairments detected in some of our and other SCA2, SCA3 and SCA7 patients upon bedside examination or neurophysiological investigation. However, further clinical studies are required to resolve the striking discrepancy between the consistent involvement of the brainstem auditory system observed in this study and the comparatively low frequency of reported auditory impairments in SCA2, SCA3 and SCA7 patients
Peripheral Nerve Regeneration and Functional Nerve Recovery After Reconstruction with a Thin-Walled Biodegradable Poly(DL-lactide-ε-caprolactone) Nerve Guide
The aim of this study was to evaluate functional nerve recovery after reconstruction of a 1 em gap in the sciatic nerve of the rat, with a thin-walled biodegradable poly(DLLA-ε-CL) nerve guide. To evaluate both motor and sensory nerve recovery, walking track analysis and electrostimulation tests were carried out after implantation periods ranging from 3 to 26 weeks post-operatively. The first signs of functional nerve recovery could already be observed after 5 weeks. From the histological analysis, it could be concluded that most of the thin-walled nerve guides had collapsed. Despite collapsing, functional nerve recovery was relatively good after 26 weeks (motor nerve recovery 54% and sensory nerve recovery 100%), probably due to guidance of the regenerating nerve fibers along the outside of the poly(DLLA-ε-CL) nerve guide. This thin-walled nerve guide should, therefore, be used in combination with mechanical support
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