73 resultados para myelin sheath

em BORIS: Bern Open Repository and Information System - Berna - Suiça


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Lipid resonances from mobile lipids can be observed by (1)H NMR spectroscopy in multiple tissues and have also been associated with malignancy. In order to use lipid resonances as a marker for disease, a reference standard from a healthy tissue has to be established taking the influence of variable factors like the spinning rate into account. The purpose of our study was to investigate the effect of spinning rate variation on the HR-MAS pattern of lipid resonances in non-neoplastic brain biopsies from different regions and visualize polar and non-polar lipids by fluorescence microscopy using Nile Red staining. (1)H HR-MAS NMR spectroscopy demonstrated higher lipid peak intensities in normal sheep brain pure white matter biopsies compared to mixed white and gray matter biopsies and pure gray matter biopsies. High spinning rates increased the visibility particularly of the methyl resonances at 1.3 and the methylene resonance at 0.89ppm in white matter biopsies stronger compared to thalamus and brainstem biopsies, and gray matter biopsies. The absence of lipid droplets and presence of a large number of myelin sheaths observed in white matter by Nile Red fluorescence microscopy suggest that the observed lipid resonances originate from the macromolecular pool of lipid protons of the myelin sheath's plasma membranes. When using lipid contents as a marker for disease, the variable behavior of lipid resonances in different neuroanatomical regions of the brain and at variable spinning rates should be considered. The findings may open up interesting possibilities for investigating lipids in myelin sheaths.

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To investigate whether the compartment pressure of the rectus sheath (CPRS) reflects the intra-abdominal pressure (IAP) under various conditions of intra-abdominal hypertension (IAH) in a pig model.

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There is an interest to keep the arterial access site for percutaneous coronary interventions (PCI) small. Using sheaths for introduction of arterial catheters is standard. The effective outer diameter of the usual introducer sheaths is about 1.5 French (F) larger than the labeled size. Omitting the sheath affords a smaller access without loss of working lumen.

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Monitoring pathology/regeneration in experimental models of de-/remyelination requires an accurate measure not only of functional changes but also of the amount of myelin. We tested whether X-ray diffraction (XRD), which measures periodicity in unfixed myelin, can assess the structural integrity of myelin in fixed tissue. From laboratories involved in spinal cord injury research and in studying the aging primate brain, we solicited "blind" samples and used an electronic detector to record rapidly the diffraction patterns (30 min each pattern) from them. We assessed myelin integrity by measuring its periodicity and relative amount. Fixation of tissue itself introduced +/-10% variation in periodicity and +/-40% variation in relative amount of myelin. For samples having the most native-like periods, the relative amounts of myelin detected allowed distinctions to be made between normal and demyelinating segments, between motor and sensory tracts within the spinal cord, and between aged and young primate CNS. Different periodicities also allowed distinctions to be made between samples from spinal cord and nerve roots and between well-fixed and poorly fixed samples. Our findings suggest that, in addition to evaluating the effectiveness of different fixatives, XRD could also be used as a robust and rapid technique for quantitating the relative amount of myelin among spinal cords and other CNS tissue samples from experimental models of de- and remyelination.

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Perineurioma is an uncommon, mostly benign, spindle-cell tumor of peripheral nerve sheath origin with a predilection for the soft tissues. Although increasing awareness points to the sites of involvement by perineurioma possibly being as ubiquitous as those frequented by schwannian tumors, only one intracerebral example has been described to date. We report on a surgically resected perineurioma of the falx cerebri in an 86-year-old woman. Preoperative imaging showed an enhancing extraaxial mass of 6 cm × 5.7 cm × 3.7 cm. Histologically, the tumor consisted of a proliferation of spindle cells interwoven by a lattice of basal lamina. Alongside a prevailing soft tissue perineurioma pattern, sclerosing and reticular areas were seen as well. Tumor cells coexpressed EMA and GLUT-1, and a minority immunoreacted for smooth muscle actin. Pericellular basal lamina was decorated with collagen type IV. No staining for S100 protein was detected. Mitotic activity was virtually absent, and the MIB1 labeling index averaged 2%. Ultrastructural examination revealed abundant pinocytotic vesicles within and conspicuous tight junctions between slender cytoplasmic processes which, in turn, were encased by discontinuous basal lamina. FISH analysis confirmed loss of at least part of one chromosome 22q. This observation calls attention to perineurioma as a novel item in the repertoire of low-grade meningial spindle cell neoplasms, in the differential diagnostic context of which it is apt to being misconstrued as either meningioma, solitary fibrous tumor, or neurofibroma. Confusion with the latter bears the risk of overgrading innocuous features of perineurioma as criteria for malignancy.

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The aim of this study was to describe the tenovaginoscopic approach to the bovine common digital flexor tendon sheath (CDFTS). A comparative anatomical, ultrasonographic and endoscopic study was undertaken using 26 healthy cadaver feet from adult dairy cows. Tenovaginoscopy was performed using a rigid, 30 degrees arthroscope (length 18 cm; outer diameter 4mm) enabling a direct view of the synovial cavity and the following structures: digital flexor tendons, digital annular ligaments, lateral and medial pouches, three mesotendons, the vinculum of the superficial digital flexor tendon, and a slot-shaped opening in the manicaflexoria of the hind feet. Additionally, four clinical cases of septic tenosynovitis treated with lavage under tenovaginoscopic control were examined. Tenovaginoscopy represents a feasible, minimally invasive method for the diagnosis and treatment of septic tenosynovitis of the CDFTS, which allows the degree of alterations of the normal structures to be evaluated.

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A 14-year-old male Siberian tiger (Panthera tigris altaica) was admitted with an ulcerating mass on the right thoracic wall. Radiographic and computed tomographic evaluation indicated 2 isolated cutaneous masses without any signs of metastasis. Histology of a Tru-Cut biopsy revealed an anaplastic sarcoma with giant cells. Both tumors were resected with appropriate normal tissue margins. The size of the defect did not allow primary closure of the wound; therefore, a mesh expansion technique was attempted. Three months later, the tiger had to be euthanized due to extensive metastasis to the lungs. Histomorphological features and immunohistochemical results confirmed the diagnosis of malignant peripheral nerve sheath tumor. In contrast to domestic animal experience, the tumor had spread extensively to the lungs without local reccurrence in a short period of time. Correct diagnosis requires various immunohistochemical evaluations of the tumor tissue.

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The descriptive term hybrid peripheral nerve sheath tumor refers to any neoplasm of the neurilemmal apparatus composed of more than one pathologically defined tumoral equivalent derived from its constituent cells. Within this uncommon nosological category, participation of granular cell tumor - a neoplasm of modified Schwann cells - has been reported only exceptionally. We describe a hitherto not documented variant composed of an organoid mixture of granular cell tumor and perineurioma with plexiform growth. A solitary subcutaneous nodule of 1.5 cm diameter was excised from the right ring finger of a 19-year-old female with no antecedents of neurofibromatosis or relevant trauma. Histology revealed a monotonous, yet cytologically dimorphic proliferation of classical granular cells intermingled with flattened, inconspicuous perineurial cells. Immunohistochemical double labeling detected expression of S100 protein in the former and of EMA and GLUT-1 in the latter. While the respective staining patterns for S100 protein and EMA or GLUT-1 tended to be mutually exclusive, a minority of cells exhibited transitional granular cell/perineurial immunophenotype. Electron microscopy permitted direct visualization of a plethora of lysosomes in the granular cell moiety, and of pinocytotic vesicles and tight junctions in perineurial cells. Intratumoral axons were not detected. Expanding intraneurally, the lesion showed discrete encapsulation by the local perineurium, and resulted in plexiform growth. The MIB-1 labeling index averaged 1%. We interpret our findings as supporting evidence for the dual cell lineage to have arisen through metaplasia, with the tumor's dynamics probably having been driven by the granular cell component.

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OBJECTIVES: In patients with a clinically isolated syndrome (CIS), the time interval to convert to clinically definite multiple sclerosis (CDMS) is highly variable. Individual and geographical prognostic factors remain to be determined. Whether anti-myelin antibodies may predict the risk of conversion to CDMS in Swiss CIS patients of the canton Berne was the subject of the study. METHODS: Anti-myelin oligodendrocyte glycoprotein and anti-myelin basic protein antibodies were determined prospectively in patients admitted to our department. RESULTS: After a mean follow-up of 12 months, none of nine antibody-negative, but 22 of 30 antibody-positive patients had progressed to CDMS. Beta-Interferon treatment delayed the time to conversion from a mean of 7.4 to 10.9 months. CONCLUSIONS: In a Swiss cohort, antibody-negative CIS patients have a favorable short-term prognosis, and antibody-positive patients benefit from early treatment.

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A 70-year-old man known for recurrent abdominal gastrointestinal stroma tumor presented with a suspicious peritoneal mass demonstrated by an abdominal CT scan. Whole-body PET showed focal FDG uptake in the right hip, whereas the peritoneal mass was FDG negative. Histologic work-up of the PET positive lesion surprisingly revealed a giant cell tumor of the tendon sheath. The benignity of the peritoneal mass was confirmed by its disappearance in repeated CT scans. In general, focally increased FDG uptake should be subject to further investigations, especially in localizations that are not consistent with typical metastatic pathways of the former primary tumor.

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BACKGROUND: Treatment of depigmented skin is an unmet medical need. OBJECTIVE: Melanocytes or stem cells thereof residing in the outer root sheath (ORS) of hair follicles might be used to repigment skin. METHODS: After de-epidermisation, autologous ORS cell solutions were applied to 5 patients with vitiligo and 1 with leucoderma. RESULTS: Stable repigmentation in a variable percentage was documented in all the patients. CONCLUSION: Applying ORS-derived melanocytes is a promising technology to improve autologous melanocyte transplantation.

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An 8-year-old crossbred dog was presented with a one-month history of progressive weakness, respiratory impairment and abdominal distension. Surgical exploration revealed the presence of a splenic mass that infiltrated the mesentery and was adherent to the stomach and pancreas. The mass was composed of highly cellular areas of spindle-shaped cells arranged in interlacing bundles, streams, whorls and storiform patterns (Antoni A pattern) and less cellular areas with more loosely arranged spindle to oval cells (Antoni B pattern). The majority of neoplastic cells expressed vimentin, S-100 and glial fibrillary acidic protein (GFAP), but did not express desmin, alpha-smooth muscle actin or factor VIII. These morphological and immunohistochemical findings characterized the lesion as a malignant peripheral nerve sheath tumour (PNST). Primary splenic PNST has not been documented previously in the dog.

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Abnormal expression of heat shock proteins (HSPs) has been observed in many human neoplasms and such expression has prognostic, predictive and therapeutic implications. The aim of this study was to evaluate immunohistochemically the expression of HSP 27, HSP 32 and HSP 90 in normal canine peripheral nerves and in four benign and 15 malignant canine peripheral nerve sheath tumours (PNSTs). In normal nerve, all of the HSPs were detected in axons, epineurial fibroblasts and scattered Schwann cell bodies. Cytoplasmic expression of HSP 27 was more widespread and intense in benign PNSTs compared with malignant PNSTs (P <0.05). Widespread and intense nuclear expression of HSP 32 was also associated with benign tumours (P <0.01), while high HSP 90 immunoreactivity was detected in all tumours, suggesting that HSP 90 might represent a new therapeutic target.