Jul
16
2009
0

Cardiac phenotyping in ex vivo murine embryos using microMRI.

Microscopic MRI (microMRI) is an emerging technique for high-throughput phenotyping of transgenic mouse embryos, and is capable of visualising abnormalities in cardiac development. To identify cardiac defects in embryos, we have optimised embryo preparation and MR acquisition parameters to maximise image quality and assess the phenotypic changes in chromodomain helicase DNA-binding protein 7 (Chd7) transgenic mice. microMRI methods rely on tissue penetration with a gadolinium chelate contrast agent to reduce tissue T(1), thus improving signal-to-noise ratio (SNR) in rapid gradient echo sequences. We investigated 15.5 days post coitum (dpc) wild-type CD-1 embryos fixed in gadolinium-diethylene triamine pentaacetic acid (Gd-DTPA) solutions for either 3 days (2 and 4 mM) or 2 weeks (2, 4, 8 and 16 mM). To assess penetration of the contrast agent into heart tissue and enable image contrast simulations, T(1) and T(*) (2) were measured in heart and background agarose. Compared to 3-day, 2-week fixation showed reduced mean T(1) in the heart at both 2 and 4 mM concentrations (p < 0.0001), resulting in calculated signal gains of 23% (2 mM) and 29% (4 mM). Using T(1) and T(*) (2) values from 2-week concentrations, computer simulation of heart and background signal, and ex vivo 3D gradient echo imaging, we demonstrated that 2-week fixed embryos in 8 mM Gd-DTPA in combination with optimised parameters (TE/TR/alpha/number of averages: 9 ms/20 ms/60 degrees /7) produced the largest SNR in the heart (23.2 +/- 1.0) and heart chamber contrast-to-noise ratio (CNR) (27.1 +/- 1.6). These optimised parameters were then applied to an MRI screen of embryos heterozygous for the gene Chd7, implicated in coloboma of the eye, heart defects, atresia of the choanae, retardation of growth, genital/urinary abnormalities, ear abnormalities and deafness (CHARGE) syndrome (a condition partly characterised by cardiovascular birth defects in humans). A ventricular septal defect was readily identified in the screen, consistent with the human phenotype. Copyright (c) 2009 John Wiley & Sons, Ltd.

Written by admin in: Ischemic Brain Damage |
Jul
16
2009
0

Expression of Wnts in the developing murine secondary palate.

Morphogenesis of the mammalian secondary palate requires coordination of cell migration, proliferation, differentiation, apoptosis and synthesis of extracellular matrix molecules by numerous signal transduction pathways. Recent evidence suggests a role for members of the Wnt family of secreted cytokines in orofacial development. However, no study has systematically or comprehensively examined the expression of Wnts in embryonic orofacial tissue. We thus conducted a survey of the expression of all known Wnt genes in the developing murine secondary palate. Using an RT-PCR strategy to assay gene expression, 12 of the 19 known members of the Wnt family were found to be expressed in embryonic palatal tissue during key phases of its development. The expression of 5 Wnt family members was found to be temporally regulated. Moreover, these Wnts had unique spatio-temporal patterns of expression which suggested possible roles in palatal ontogeny.

Written by admin in: Ischemic Brain Damage |
Jul
16
2009
0

CBP/p300 and associated transcriptional co-activators exhibit distinct expression patterns during murine craniofacial and neural tube development.

Mutations in each of the transcriptional co-activator genes – CBP, p300, Cited2, Cart1 and Carm1 – result in neural tube defects in mice. The present study thus furnishes a complete and comparative temporal and spatial expression map of CBP/p300 and associated transcriptional co-activators, Cited2, Cart1 and Carm1 during the period of murine neural tube development (embryonic days 8.5 to 10.5). Each co-activator except Cart1 was expressed in the dorsal neural folds on E8.5. Although CBP and p300 are functionally interchangeable in vitro, their respective expression patterns diverge during embryogenesis before neural fold fusion is complete. CBP gene expression was lost from the neural folds by E8.75 and was thereafter weakly expressed in the maxillary region and limb buds, while p300 exhibited strong expression in the first branchial arch, limb bud and telencephalic regions on E9.5. Cart1 exhibited strong expression in the forebrain mesenchyme from E9.0 through E10.5. Although CBP, p300, Carm1 and Cited2 share temporal expression on E8.5, these co-activators have different spatial expression in mesenchyme and/or the neuroepithelium. Nevertheless, co-localization to the dorsal neural folds on E8.5 suggests a functional role in elevation and/or fusion of the neural folds. Target genes, and pathways that promote cranial neural tube fusion that are activated by CBP/p300/Carm1/Cited2/Cart1-containing transcriptional complexes await elucidation.

Written by admin in: Ischemic Brain Damage |
Jul
16
2009
0

Whole-Body Magnetic Resonance Imaging of Healthy Volunteers: Pilot Study Results from the Population-Based SHIP Study.

PURPOSE: Approximately 4000 volunteers will undergo whole-body magnetic resonance imaging (WB-MRI) within the next 3 years in the population-based Study of Health in Pomerania (SHIP). Here we present a pilot study conducted (a) to determine the feasibility of adding a WB-MRI protocol to a large-scale population-based study, (b) to evaluate the reliability of standardized MRI interpretation, and (c) to establish an approach for handling pathological findings. MATERIALS AND METHODS: The institutional review board approved the study, and oral and written informed consent was obtained from each participant. Two hundred healthy volunteers (99 women, 101 men; mean age 48.3 years) underwent a standardized WB-MRI protocol. The protocol was supplemented by contrast-enhanced cardiac MRI and magnetic resonance (MR) angiography in 61 men (60.4 %) and cardiac MRI and MR mammography in 44 women (44.4 %). MR scans were evaluated independently by two readers. Abnormalities were discussed by an advisory board and classified according to the need for further clinical work-up. RESULTS: One hundred ninety-four (97.0 %) WB-MRI examinations were successfully completed in a mean scan time per subject of 90 minutes. There were 431 pathological findings in 176 (88 %) of the participants. Of those 45 (10.4 %) required further clinical work-up and 386 (89.6 %) characterized as benign lesions did not. The interobserver agreement for the detection of pathological findings was excellent (kappa = 0.799). CONCLUSION: The preliminary results presented here indicate that a large prospective, population-based study using WB-MRI is feasible and that the results of image analysis are reproducible. A variety of positive findings provide valuable information regarding disease prevalence in a general adult population.

Written by admin in: Ischemic Brain Damage |
Jul
16
2009
0

Assessment of endocrine abnormalities in severe traumatic brain injury: a prospective study.

OBJECTIVE: The frequency and pattern of endocrine abnormalities among patients with traumatic brain injury have been the subject matter of very few studies. This study was intended to assess the pattern of endocrine dysfunction following severe head injury. METHODS: Severe head injury patients admitted to the Department of Neurosurgery, All India Institute of Medical Sciences, New Delhi, from January to December in 1 year formed the study group. Apart from clinical assessment, NCCT of the head was performed on all patients on admission. A complete anterior pituitary hormone analysis was performed within 24 h of injury and was repeated at 2 weeks, 3 months and 6 months amongst patients who survived. RESULTS: A total of 99 patients were included in the study. Forty of our patients succumbed in the hospital. Rest of the patients were followed up for 6 months. Elevations of cortisol followed by prolactin were the most common hormonal derangements at admission. Midline shift on CT scans was inversely related to cortisol elevation and directly related to GH elevation. Infarct on CT scans was inversely related to cortisol and LH elevation. A significant alteration was found in the decreasing trend of the mean T4 values and normalisation or a decreasing trend from initially elevated mean cortisol and GH levels during follow-up (p < 0.05). CONCLUSIONS: This study reveals that abnormalities in hormonal profiles appear to be relatively common in severe traumatic brain injury and fluctuate significantly over at least 6 months; there is a correlation with age and radiological findings. Performance of hormonal analysis evaluation should be considered in patients with severe brain injury so that appropriate hormonal replacement can be done to optimise the clinical outcome.

Written by admin in: Ischemic Brain Damage |
Jul
16
2009
0

Somatostatin receptor scintigraphy might be useful for detecting skeleton abnormalities in patients with multiple myeloma and plasmacytoma.

PURPOSE: Somatostatin receptor expression has been demonstrated on a number of plasma cell lines. Therefore, we questioned whether somatostatin receptor scintigraphy (SRS) can be used to demonstrate in vivo multiple myeloma (MM) activity. METHODS: SRS was performed in newly diagnosed (n = 9) or relapsing (n = 18) MM patients or in patients with localized plasmacytoma (n = 2). The results were compared with radiographic findings. RESULTS: A positive SRS was demonstrated in 44% of the newly diagnosed patients, in 83% of the relapsed patients and in both patients with plasmacytoma. The SRS findings corresponded with radiographic abnormalities in 40% of the patients. However, in relapsed patients 60% demonstrated increased SRS uptake in areas without new radiographic abnormalities. The positive SRS corresponded with histologically proven disease activity and responded upon treatment. Moreover, immunohistochemical staining of MM material demonstrated concordant somatostatin receptor sst3 staining in five of six patients. CONCLUSION: These results demonstrate that SRS is a valuable tool to detect disease activity, especially in relapsing MM patients.

Written by admin in: Ischemic Brain Damage |
Jul
16
2009
0

The ubiquitin proteasome system in neuropathology.

The ubiquitin proteasome system (UPS) orchestrates the turnover of innumerable cellular proteins. In the process of ubiquitination the small protein ubiquitin is attached to a target protein by a peptide bond. The ubiquitinated target protein is subsequently shuttled to a protease complex known as the 26S proteasome and subjected to degradative proteolysis. The UPS facilitates the turnover of proteins in several settings. It targets oxidized, mutant or misfolded proteins for general proteolytic destruction, and allows for the tightly controlled and specific destruction of proteins involved in development and differentiation, cell cycle progression, circadian rhythms, apoptosis, and other biological processes. In neuropathology, alteration of the UPS, or mutations in UPS target proteins may result in signaling abnormalities leading to the initiation or progression of tumors such as astrocytomas, hemangioblastomas, craniopharyngiomas, pituitary adenomas, and medulloblastomas. Dysregulation of the UPS may also contribute to tumor progression by perturbation of DNA replication and mitotic control mechanisms, leading to genomic instability. In neurodegenerative diseases caused by the expression of mutant proteins, the cellular accumulation of these proteins may overload the UPS, indirectly contributing to the disease process, e.g., sporadic Parkinsonism and prion diseases. In other cases, mutation of UPS components may directly cause pathological accumulation of proteins, e.g., autosomal recessive Parkinsonism and spinocerebellar ataxias. Defects or dysfunction of the UPS may also underlie cognitive disorders such as Angelman syndrome, Rett syndrome and autism, and muscle and nerve diseases, e.g., inclusion body myopathy and giant axon neuropathy. This paper describes the basic biochemical mechanisms comprising the UPS and reviews both its theoretical and proven involvement in neuropathological diseases. The potential for the UPS as a target of pharmacological therapy is also discussed.

Written by admin in: Ischemic Brain Damage |
Jul
16
2009
0

Prospective study on long-term treatment with oxcarbazepine in pediatric epilepsy.

Following a previous preliminary report on a group of children suffering from partial epilepsies, we present the final considerations on the same group in order to evaluate the long-term efficacy, tolerability and safety of oxcarbazepine (OXC). We enrolled 36 patients (mean age 8.5), between January 2003 and December 2004, with new diagnosis of partial epilepsy: 25 patients were affected by idiopathic partial epilepsy, eight by symptomatic epilepsy and three by cryptogenic epilepsy. Each patient was scheduled to attend the center four times after the initial examination: 3 months (T1), 12 months (T2), 24 (T3) months and 36 (T4) months after the beginning of OXC-monotherapy (T0). At the end of our study, 20 patients were seizure free (SF): nine stopped OXC because of SF for at least 2 years, 11 were still on therapy. One patient showed a reduction of seizure frequency >/=50%, three were non responders (but still on therapy), nine stopped OXC due to a non-responder condition during follow-up before T4 and one because of adverse effects. At the end of the study no EEG focal abnormalities became generalized because of treatment. Normalization of EEG was observed in ten patients. Our preliminary findings have been confirmed. OXC can be considered an effective and well tolerated first line drug for long-term monotherapy in children with epilepsy, both for idiopathic and symptomatic/cryptogenic forms.

Written by admin in: Ischemic Brain Damage |
Jul
16
2009
0

Suicide attempt using pure methanol with hospitalization of the patient soon after ingestion: case report.

CONTEXT: Most patients with methanol poisoning typically show up one to several days after ingestion, presenting severe acidosis, visual disorders, or both. Reports of hospitalization less than 6 h after exposure are unusual. We describe a case of attempted suicide using methanol admitted 3 h after ingestion. CASE REPORT: A 52-year-old male was hospitalized 3 h after intentional ingestion of 150 ml of 99.9% methanol with no co-ingestion of ethanol. He was alert and cooperative, presenting nausea and vertigo, and reporting six episodes of vomiting. Physical examination showed no remarkable features. A blood sample for methanol and ethanol determination was obtained 4 h after ingestion. The result (available 10 h after ingestion) showed 70 mg/dl of methanol, without detectable ethanol. He was treated with a loading dose of 10% ethanol solution (7 ml/kg, intravenously), followed by a maintenance dose of 0.9-1.0 ml/kg/h intravenously (10 to 51 h); hemodialysis (19 to 27 h, together with 2.1 ml/kg/h of 10% ethanol intravenously); and folinic acid intravenously (50 mg every 6 h, from 4 to 51 h). He developed mild/moderate metabolic acidosis without acidemia and was discharged on day four after ophthalmological evaluation and cerebral computed tomography scan, without abnormalities. Follow-up revealed no sequelae. CONCLUSION: This could be classified as a potentially severe case of methanol poisoning, according to the amount and concentration of methanol ingested, and blood methanol concentration at 4 h. The good outcome was attributable to early hospitalization and early antidotal therapy with hemodialysis, starting at 10 and 19 h, respectively.

Written by admin in: Ischemic Brain Damage |
Jul
16
2009
0

Centrosome abnormalities during porcine oocyte aging.

Centrosomes are critically important for maintaining meiotic spindle integrity in the meiosis II (MII) stage where oocytes are arrested in most mammalian species before fertilization takes place. In women of advanced ages or during in vitro fertilization (IVF) procedures, aneuploidy is frequently seen as a result of oocyte aging, which is strongly related to centrosome instability. Abnormal distribution of centrosomes and microtubules has been reported in aging human and mouse oocytes. This study reports the dynamic changes of centrosomes and the microtubule cytoskeleton in porcine oocytes during aging and treatment by caffeine to restore spindle integrity in aging oocytes. We tested the effects of caffeine on the MII spindle with focus on microtubules and on the centrosome proteins gamma-tubulin and NuMA (nuclear mitotic apparatus protein). The results revealed that in porcine oocytes aged for 48 hr, centrosomes were absent and spindles became abnormal and disorganized; however, caffeine could prevent these changes or restore centrosome integrity in the meiotic spindle poles and displayed similar MII spindles as those seen in fresh oocytes. Environ. Mol. Mutagen., 2009. (c) 2009 Wiley-Liss, Inc.

Written by admin in: Ischemic Brain Damage |

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