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1

Posterior fossa arachnoid cysts and cerebellar tonsillar descent: short review  

Microsoft Academic Search

The objective of this study was to analyze the association of cerebellar tonsillar descent and syringomyelia in patients with\\u000a posterior fossa arachnoid cysts. We reviewed the medical records of ten patients (mean, age 33; range, 24–49 years) diagnosed\\u000a with posterior fossa arachnoid cyst and tonsillar descent. Symptoms evolved over a mean of 12 months (range, 6 months to 3 years).\\u000a Syringomyelia was present in

Marcelo Galarza; Antonio López López-Guerrero; Juan F. Martínez-Lage

2010-01-01

2

Posterior fossa arachnoid cysts and cerebellar tonsillar descent: short review.  

PubMed

The objective of this study was to analyze the association of cerebellar tonsillar descent and syringomyelia in patients with posterior fossa arachnoid cysts. We reviewed the medical records of ten patients (mean, age 33; range, 24-49 years) diagnosed with posterior fossa arachnoid cyst and tonsillar descent. Symptoms evolved over a mean of 12 months (range, 6 months to 3 years). Syringomyelia was present in six cases. Six patients underwent a suboccipital craniectomy, three cases underwent an additional C1 laminectomy, and a further case had a limited craniectomy and tonsillar reduction. Three patients were also treated for hydrocephalus: one with a ventriculoperitoneal shunt and two with endoscopic third ventriculostomy. Two patients had conservative treatment. The posterior fossa arachnoid cysts were located at the vermis-cisterna magna (n = 4), the cerebellar hemispheres (n = 2), the cerebellopontine angle (n = 3), and the quadrigeminal cistern (n = 1). A patient with achondroplasia showed features of platybasia. Associated malformations included craniofacial dysmorphism in a patient diagnosed of trichorhinophalangeal syndrome and a case with a primary temporal arachnoid cyst. After a mean follow-up of 2 years (range, 3 months to 5 years), four patients showed resolution of their neurological symptoms, and two exhibited persisting ocular findings. Headaches and nuchalgia improved in four cases and persisted in four. Syringomyelia was resolved in four patients and improved in two. Patients harboring a posterior fossa arachnoid cyst may evolve with acquired Chiari malformation and syringomyelia. Initial management should be directed to decompressing the foramen magnum and should include the resection of the arachnoid cyst's walls. A wait-and-see attitude can be implemented in selected cases. In our experience, hydrocephalus should be properly addressed before treating the arachnoid cyst. PMID:20480382

Galarza, Marcelo; López-Guerrero, Antonio López; Martínez-Lage, Juan F

2010-05-18

3

Tonsillar ectopia and headaches.  

PubMed

Tonsillar ectopia, encompassing slight descent of the cerebellar tonsils and Chiari I malformations, are disorders observed routinely in older children and adults and are believed to be an acquired form of the Chiari malformations. This entity is different from the other Chiari malformations in that hydrocephalus plays no role in its evolution. More likely it is a disorder of para-axial mesoderm, characterized by posterior fossa hypoplasia and content overcrowding, and not an embryologic anomaly of neuroectoderm. The prevalence of tonsillar ectopia to my knowledge has not been studied. The incidence of Chiari I malformations ranges from less than 1%to 3% at various tertiary centers. The occipital and exertional headache associated with this malformation can be observed in subjects who have new-onset tonsillar ectopia resulting from repeated lumbar puncture,idiopathic intracranial hypotension, lumboperitoneal shunting, or spontaneous development [34-36]. This new-onset headache can remit with return to normal tonsil positioning. These findings support the proposal that pressure dissociation gradients and perhaps traction of pain-sensitive tissues play a role in generation of the headache observed in this malformation. In accordance with this idea, the extent of tonsillar descent is irrelevant alone,and the degree of posterior fossa hypoplasia and decrement of CSF flow velocity are better defining factors for determining the clinical significance of tonsillar ectopia. PMID:15062536

Arnett, Bridgette C

2004-02-01

4

Bilateral retrocerebellar arachnoid cysts exerting mass effect and associated with cerebellar tonsillar ectopia in an otherwise healthy adult.  

PubMed

Rarely, midline or unilateral posterior fossa arachnoid cysts (ACs) exert local mass effect resulting in the symptoms and signs of cerebellar and brainstem dysfunction. These cysts are sometimes seen in conjunction with cerebellar tonsillar ectopia (TE), although the relationship between these two entities is unclear. Bilateral ACs in the posterior fossa are virtually unprecedented. We describe the case of a 33-year-old man with a history of multiple minor head injuries observed to harbour asymptomatic, bilateral cerebrospinal fluid-density collections over the cerebellar hemispheres. Six years later, he presented with headaches, limb paraesthesias, and drop attacks. Computed tomography, magnetic resonance imaging, and operative findings during burrhole drainage of the lesions showed bilateral posterior fossa ACs, with associated cerebellar TE of 11 mm. The cysts partially recurred, necessitating reopening of the burrholes, after which the patient's symptoms resolved entirely. We then discuss the challenges in diagnosing this unusual case, the relationship between AC and TE, and the role of minor head injury in the symptomatic progression of AC. PMID:23615422

Killeen, Tim; Tromop-VAN-Dalen, Chani; Alexander, Hamish; Wickremesekera, Agadha

2013-01-01

5

Tonsillar Cancer  

MedlinePLUS

... from the cancer's spread to a lymph node (metastasis) may be noticed before any other symptoms. Symptoms ... STUDENT STORIES Pronunciations bronchoscopy computed tomography esophagus larynx metastasis papilloma papillomavirus tonsillar Back to Top Previous: Nasopharyngeal ...

6

Adeno-tonsillar surgery in Italy  

PubMed Central

Summary Indications to surgery for adeno-tonsillar inflammatory disorders and analysis of the effectiveness of surgical treatment, compared with watchful waiting strategy, continue to be the subject of scientific debate. The present investigation focuses on the surgical activity of 14 Italian Otorhinolaryngological Units between 1999 and 2004. Surgical interventions (adeno-tonsillectomy, adenoidectomy, tonsillectomy) on 26915 children (age range: 2-11 years) were considered. Data on adeno-tonsillar interventions were analysed in relation to other interventions of ENT interest, performed in the same units and in the same period. Adeno-tonsillar interventions accounted for 35.4% of all operations of ENT interest. Adeno-tonsillectomy accounted for 56.6% of overall adeno-tonsillar operations, adenoidectomy 31.6%, tonsillectomy 11.8%. The percentage for the three interventions was homogeneous in the period of the study and in the recruited units. The percentage of children who underwent adeno-tonsillar surgery in paediatric units was higher as compared to general units, as far as concerns the overall number of operations performed. In southern Italy, the number of adeno-tonsillar interventions, in general, and of adeno-tonsillectomy, in particular, was higher compared to that in northern Italy. Results of the present study suggest that environmental factors, cultural issues and local health demands, may influence indications and, therefore, the different incidence of the operations under consideration in the units taking part in the investigation.

G. Motta; Casolino, D; Cassiano, B; Conticello, S; Esposito, E; Galletti, F; Galli, V; Larotonda, G; Laudadio, P; Mansi, N; Mevio, E; Mira, E; Motta Jr, G; Rinaldi Ceroni, A; Tarantino, V; Tavormina, P; Vicini, C; Motta, S

2008-01-01

7

Cerebellar Hypoplasia  

MedlinePLUS

... Contact NINDS Adobe Reader Microsoft Word Viewer NINDS Cerebellar Hypoplasia Information Page Table of Contents (click to jump ... is being done? Clinical Trials Organizations What is Cerebellar Hypoplasia? Cerebellar hypoplasia is a neurological condition in which ...

8

Radiofrequency Treatment for Obstructive Tonsillar Hypertrophy  

Microsoft Academic Search

Objective: To evaluate the safety and efficacy of in- office, temperature-controlled radiofrequency submu- cosal tissue volume reduction using the Somnoplasty pro- cedure for the treatment of symptomatic chronic obstructive tonsillar hypertrophy. Design: A prospective, nonrandomized, 3-phase pro- tocol using in vitro and in vivo studies associated with operative tonsillectomy and clinical procedures per- formed in-office. Setting: Hospital operating room and

Lionel M. Nelson

2000-01-01

9

Innate immune reactions in locally limited tonsillar cancer.  

PubMed

Tonsillar cancers often present as locally limited tumors but with cervical metastases. When the primary tumors of tonsillar cancers with cervical metastases are as small as clinically occult, the clinical features are diagnosed as primary-unknown cervical metastases. However, little is known as to why small tonsillar cancers establish cervical metastases. The aim of this study was to investigate a possibility that innate immune reactions might suppress the growth of tumors arising in the palatine tonsils, because the palatine tonsils contain various immune effector cells. Infiltration of natural killer (NK) cells and macrophages, which are major innate immune cells, in surgically removed tumors from patients with locally limited tonsillar cancers and tongue cancers was immunohistochemically studied by using anti-CD57 and anti-CD68 antibodies. Phagocytosis of the tumor cells by macrophages was also studied by dual immunofluorescence labeling. The number of infiltrating CD57+ NK cells and CD68+ macrophages was significantly increased in locally limited tonsillar cancers in comparison to normal tonsils and tongue cancers. The phagocytosis of tumor cells by CD68+ macrophages was observed significantly more frequently in tonsillar cancers than in tongue cancers. These results indicated that the innate immune reactions were more strongly induced in locally limited tonsillar cancers than in tongue cancers, and might therefore suppress the growth of primary tumors in palatine tonsils. The innate immune reactions against cancers in palatine tonsils were suggested to be one of the possible etiologies for the developing of primary-unknown cervical metastases. PMID:23471570

Kuratomi, Yuichiro; Kusano, Kenichiro; Shimazu, Rintaro; Inokuchi, Akira

2013-03-08

10

Cerebellar Degeneration  

MedlinePLUS

... Degeneration? Cerebellar degeneration is a process in which neurons in the cerebellum - the area of the brain ... proteins that are necessary for the survival of neurons. Associated diseases: Diseases that are specific to the ...

11

Cerebellar ganglioglioma.  

PubMed

The cerebellar location of ganglioglioma (GG) is exceptional. We report one case of a 27-year-old man who underwent an intracranial hypertension syndrome and a static cerebellar syndrome. Brain magnetic resonance images revealed a cyst image in the vermis. Histological study after surgical removal, revealed a ganglioglioma tumor. Through this case and literature review, the authors discuss some epidemiological, histological, clinical, radiological and management features of this very rare tumor. PMID:22826736

Fedoul, Badr; Souirti, Zouhayr

2012-05-22

12

Cerebellar ganglioglioma  

PubMed Central

The cerebellar location of ganglioglioma (GG) is exceptional. We report one case of a 27-year-old man who underwent an intracranial hypertension syndrome and a static cerebellar syndrome. Brain magnetic resonance images revealed a cyst image in the vermis. Histological study after surgical removal, revealed a ganglioglioma tumor. Through this case and literature review, the authors discuss some epidemiological, histological, clinical, radiological and management features of this very rare tumor.

Fedoul, Badr; Souirti, Zouhayr

2012-01-01

13

Participation of autonomic nerve in tonsillar focal infection.  

PubMed

Participation of the autonomic nerve in tonsillar focal infection was investigated by measuring neurotransmitters, receptors and microvibration. In focal infection patients, the volume of norepinephrine in the tonsil increased significantly and the number of a-adrenergic receptors decreased. These findings suggest that the focally infected tonsil exhibits a high degree of sympathetic nerve activity. The ratio of N-type in microvibration decreased systematically, which indicates some imbalance or immaturity of the autonomic nervous system in focal infection patients. Based on this data, the production mechanism of tonsillar focal infection was speculated from the point of view of the autonomic nerve. PMID:3223255

Yamashita, T; Kozuki, K; Kubo, N; Ishibe, T; Kumazawa, H; Otani, K; Kumazawa, T

1988-01-01

14

Cerebellar mutism.  

PubMed

Cerebellar mutism occurs in about 25% of children following posterior fossa tumor surgery. It is usually accompanied by other neurological and behavioral disturbances. Mutism is transient in nature lasting several days to months and is frequently followed by dysarthria. In addition, impairment of language and other neuropsychological functions can be found after long term follow up in the majority of patients. The pathophysiological background of mutism may be higher speech dysfunction mediated by crossed cerebello-cerebral diaschisis which is frequently found during the mute period. Foremost injury to the bilateral dentatothalamocortical tract appears to be critical for the development of cerebello-cerebral diaschisis and subsequent mutism. Direct cerebellar injury is the likely reason for persisting deficits after the mute period. Minimization of injury to the dentatothalamocortical tract during surgery may be promising in the prevention of mutism. While there is no established treatment of mutism, early speech and rehabilitation therapy is recommended. PMID:23398780

Küper, Michael; Timmann, Dagmar

2013-02-01

15

Meningococcal Encephalitis associated with cerebellar tonsillar herniation and acute cervicomedullary injury.  

PubMed

A 13-year-old girl presented with a progressive ascending paralysis, bulbar dysfunction and finally respiratory arrest. Magnetic resonance (MR) showed acute cervicomedullary injury and hindbrain herniation. An emergency foramen magnum decompression and external ventricular drainage insertion were performed, and meningococcal infection was diagnosed. The patient recovered completely. Meningococcal encephalitis may have an atypical presentation, and a surgery can optimise the outcome. PMID:23391099

Fayeye, O; Pettorini, B L; Smith, M; Williams, H; Rodrigues, D; Kay, A

2013-02-01

16

Cerebellar hypermetabolism in paraneoplastic cerebellar degeneration  

Microsoft Academic Search

A 51 year old man with paraneoplastic cerebellar degeneration from gastric adenocarcinoma showed cerebellar hypermetabolism and increased perfusion on brain FDG-PET scan and SPECT during the acute stage of his illness. The patient underwent subtotal gastrectomy. The intensity of the hypermetabolism had decreased markedly on follow-up FDG-PET 3 months later following two cycles of chemotherapy. We suggest that the cerebellar

K-D Choi; J S Kim; S-H Park; Y K Kim; S E Kim; P S Smitt

2006-01-01

17

Cerebellar infarcts and hemorrhages.  

PubMed

Cerebellar infarction accounts for about 3.4% of all ischemic strokes. Cerebellar syndromes are principally characterized by cerebellar symptoms and signs which depend on the involved vascular territories. In the Perugia Stroke Registry, infarct areas have included the superior cerebellar artery region in 36% of patients, the anterior inferior cerebellar artery region in 12%, and the posterior inferior cerebellar artery region in 40%; 12% of patients have had multiple vascular region involvement. 50% of the patients have had concurrent brainstem infarcts. Cerebellar hemorrhage accounts for about 10% of all intracranial hemorrhages and about 10% of all cerebellar strokes. Both stroke types can be worsened by complications due to a significant mass effect and brainstem compression. These events can lead to clinical deterioration which induces stupor and coma with a very high fatality rate. PMID:22377889

Venti, Michele

2012-02-14

18

Post-tonsillectomy pulmonary complication in a patient with tonsillar myeloid sarcoma.  

PubMed

Myeloid sarcoma in a patient with myelodysplastic syndrome (MDS) manifesting as a non-healing tonsillar ulcer is an extremely rare occurrence. We report the case of a 57-year-old male smoker with a non-healing tonsillar ulcer who underwent tonsillectomy to rule out tonsillar carcinoma after failed antibiotic therapy. On postoperative day 2, he presented with a temperature of 40°C and white blood cell count of 34700/?L. Antibiotic therapy was begun; however, he died 1 day later due to pulmonary infection and septic shock. Though extremely rare, tonsillar involvement of MDS should be considered in the differential diagnosis of a non-healing tonsillar lesion. When definitive diagnosis requires a tissue sample, punch biopsy may be preferable to tonsillectomy in a patient who may be immunocompromised, and appropriate prophylactic antibiotics should be administered. PMID:21234822

Cheng, Chia-Chi; Ueng, Shir-Hwa; Li, Hseuh-Yu; Chen, Huan-Wu; Chen, Tsung-Ming; Lee, Li-Ang; Kang, Chung-Jan; Kuo, Ying-Ling; Huang, Hao-Chun; Hsiao, Han-Ren; Fang, Tuan-Jen

2011-01-15

19

Descent and descent groups in lovedu social structure  

Microsoft Academic Search

The basic unit in Lovedu society is the extended family, the minimal descent group, of three, and occasionally four generations living together in a village under the control of the patriarch, or, after his death, of his son, the eldest in the chief house. It is a corporate group of considerable importance.An initial examination in this paper of situations in

Eileen Jensen Krige

1985-01-01

20

EXOMARS Descent Module GNC Performance  

NASA Astrophysics Data System (ADS)

The ExoMars mission is the first ESA led robotic mission of the Aurora Programme and combines technology development with investigations of major scientific interest. Italy is by far the major contributor to the mission through the strong support of the Italian Space Agency (ASI). ExoMars will search for traces of past and present life, characterize the Mars geochemistry and water distribution, improve the knowledge of the Mars environment and geophysics, and identify possible surface hazards to future human exploration missions. ExoMars will also validate the technology for safe Entry, Descent and Landing (EDL) of a large size Descent Module (DM) carrying a Rover with medium range surface mobility and the access to subsurface. The ExoMars project is presently undergoing its Phase B1 with Thales Alenia Space-Italia as Industrial Prime Contractor. Additionally, as Descent Module responsible, a dedicated simulation tool is under development in Thales Alenia Space-Italia, Turin site, for the end-to-end design and validation / verification of the DM Entry Descent and Landing.

Portigliotti, S.; Capuano, M.; Montagna, M.; Martella, P.; Venditto, P.

2007-08-01

21

Automatic 'Descente Infinie' Induction Reasoning  

Microsoft Academic Search

We present a framework and a methodology to build and analyse automatic provers using the 'Descente Infinie' induction princi- ple. A stronger connection between different proof techniques like those based on implicit induction and saturation is established by uniformly and explicitly representing them as applications of this principle. The framework offers a clear separation between logic and computation, by the

Sorin Stratulat

2005-01-01

22

Online learning via congregational gradient descent  

Microsoft Academic Search

We propose and analyse a populational version of stepwise gradient descent suitable for a wide range of learning problems. The algorithm is motivated by genetic algorithms which update a population of solutions rather than just a single representative as is typical for gradient descent. This modification of traditional gradient descent (as used, for example, in the backpropogation algorithm) avoids getting

Kim L. Blackmore; Robert C. Williamson; Iven M. Y. Mareels; William A. Sethares

1997-01-01

23

Emergency Descent Plans, Procedures, and Context  

Microsoft Academic Search

When an emergency descent to land is required, planning this descent can be challenging; decisions must be made quickly but may dramatically alter the options available later. This study examines portraying emergency descent plans to pilots as procedures in which important elements of context are highlighted. Under time pressure, pilots evaluated plans which were presented with a variety of contextual

Amy Pritchett; Jennifer Ockerman

2002-01-01

24

Tonsillar tissue penetration of dirithromycin after multiple doses.  

PubMed

Dirithromycin is a new macrolide antibiotic that is effective against group A beta-hemolytic streptococcal pharyngotonsillitis. This prospective, multicenter, randomized study compared the serum and tonsil tissue concentrations of erythromycylamine (to which dirithromycin is rapidly converted by nonenzymatic hydrolysis during absorption) and erythromycin after 5- and 10-day regimens of dirithromycin and erythromycin, respectively. Thirty-nine patients undergoing elective tonsillectomy but without active tonsillitis were assigned in randomized fashion to receive dirithromycin 500 mg orally once daily (n = 22) or erythromycin base 250 mg orally four times daily (n = 17). Data from 12 patients receiving dirithromycin and 10 receiving erythromycin were eligible for analysis. Mean serum concentrations (+/-standard deviation) of erythromycylamine and erythromycin were 0.20 +/- 0.07 microgram/mL and 0.12 +/- 0.25 microgram/mL, respectively, after the 5-day regimen and 0.17 +/- 0.10 microgram/mL and 1.57 +/- 3.16 micrograms/mL, respectively, after the 10-day regimen. The mean serum concentration of erythromycin after 10 days was skewed by the data for one of the six patients in the group (concentration of > 8 micrograms/mL). Mean concentrations of erythromycylamine in tonsil tissue were 4.62 +/- 0.97 micrograms/ g after 5 days and 3.47 +/- 2.84 micrograms/g after 10 days. Concentrations in tonsillar tissue were undetectable in all patients given erythromycin for 5 days and in 4 of the 6 patients given erythromycin for 10 days. The high concentrations of erythromycylamine in tonsillar tissue agree with the clinical efficacy seen in the treatment of group A beta-hemolytic streptococcal tonsillopharyngitis with dirithromycin. PMID:8889904

Benson, J M; Arnold, J; Manning, S C; Coleman, D L; Sides, G D; Conforti, P M; Lemon, E; Watkins, V S

1996-09-01

25

[Isolation of FDC-lymphocyte clusters from human tonsillar tissues].  

PubMed

Follicular B cells and follicular dendritic cells (FDCs) form FDC-lymphocyte clusters and play a central role in events related to humoral immunity in the lymphoid follicle (LF). The secondary LF is divided into five zones, each of which exhibits functional differences. However, the distribution of the clusters across the five follicular zones remains unclear. We here report a procedure for isolating FDC-lymphocyte clusters from fixed tonsillar tissues and compare of the structure of clusters isolated from three follicular zones: the mantle, light and dark zones. First, the germinal centers (GCs) of the secondary LFs were removed under a stereoscope, and the GCs were enzymatically digested for 20, 30, 40 and 50 minutes at 37 degrees C. The FDC-lymphocyte clusters were then isolated using a discontinuous density gradient and a Magnetic Particle Concentrator, followed by microbeads. The number of isolated medium sized clusters composed of 6-25 cells was greatest when the samples were incubated for 40 minutes. To detect the mantle, light and dark zones, and GCs, isolated FDC-lymphocyte clusters from each zone were immunostained. Their cell structures were then compared. The clusters were composed mainly of B cells (comprising about 80% of the cells in each cluster, on average), T cells, natural killer/T cells and macrophages were also observed, but less frequently. The proportions of CD 45 RO-positive cells and CD4-positive cells were clearly different for each zone, with CD4-positive cells in the majority. No clear differences in isolated clusters from fixed and unfixed tonsillar tissues were observed. Our data indicate that this procedure is suitable for isolating FDC-lymphocyte clusters from fixed lymphoid tissues and that the proportions of cells composing the clusters differ in the three follicular zones. PMID:11187756

Takemoto, N

2000-11-01

26

Intracapsular tonsillar reduction (partial tonsillectomy): reviving a historical procedure for obstructive sleep disordered breathing in children  

Microsoft Academic Search

ObjectiveWe sought to reintroduce a historical procedure—intracapsular tonsillar reduction (partial tonsillectomy or tonsillotomy)—for tonsillar hypertrophy causing obstructive sleep disordered breathing (OSDB) in children, as well as to determine whether partial tonsillectomy, compared with conventional (total) tonsillectomy when performed by more than one surgeon, is equally effective for the relief of OSDB while resulting in less pain and more rapid recovery.

Peter J Koltai; C. Arturo Solares; Jeffery A Koempel; Keiko Hirose; Tom I Abelson; Paul R Krakovitz; James Chan; Meng Xu; Edward J Mascha

2003-01-01

27

MRI in cerebellar hypoplasia  

Microsoft Academic Search

Cerebellar hypoplasia may present with a wide variety of neurological and systemic features, ranging from aplasia causing neonatal death to mild hypoplasia in an asymptomatic adult. MRI clearly documents the size of the cerebellum and any associated abnormalities. We describe 7 cases of cerebellar hypoplasia of varying aetiology-3 inherited, 2 associated with spinal dysraphism, 1 with Joubert's syndrome and 1

N. deSouza; R. Chaudhuri; J. Bingham; T. Cox

1994-01-01

28

Descent theory for semiorthogonal decompositions  

SciTech Connect

We put forward a method for constructing semiorthogonal decompositions of the derived category of G-equivariant sheaves on a variety X under the assumption that the derived category of sheaves on X admits a semiorthogonal decomposition with components preserved by the action of the group G on X. This method is used to obtain semiorthogonal decompositions of equivariant derived categories for projective bundles and blow-ups with a smooth centre as well as for varieties with a full exceptional collection preserved by the group action. Our main technical tool is descent theory for derived categories. Bibliography: 12 titles.

Elagin, Alexei D

2012-05-31

29

Numerical analysis of the orthogonal descent method  

SciTech Connect

The author of the orthogonal descent method has been testing it since 1977. The results of these tests have only strengthened the need for further analysis and development of orthogonal descent algorithms for various classes of convex programming problems. Systematic testing of orthogonal descent algorithms and comparison of test results with other nondifferentiable optimization methods was conducted at TsEMI RAN in 1991-1992 using the results.

Shokov, V.A.; Shchepakin, M.B.

1994-11-01

30

Family history of adenotonsillectomy as a risk factor for tonsillar hypertrophy and snoring in childhood.  

PubMed

OBJECTIVE: Accumulating evidence supports a role for familial predisposition in the pathogenesis of OSA. In this study, it was hypothesized that parental history of adenoidectomy and/or tonsillectomy (AT), which is the standard treatment for pediatric OSA is a risk factor for tonsillar hypertrophy and habitual snoring (>3 nights/week) in the offspring. METHODS: Children were recruited from the emergency department and the pediatric pulmonology clinic. Paternal or maternal history of AT (explanatory variables) and habitual snoring (outcome) were recorded and presence of tonsillar hypertrophy (outcome) was assessed. RESULTS: Two hundred ninety-two children (2-14 y.o.) were recruited; 37 (12.7%) of them had paternal history of AT, 39 (13.4%) maternal history of AT, 60 (20.5%) tonsillar hypertrophy, and 48 (16.4%) habitual snoring. Maternal and paternal history of AT were significantly associated with the presence of tonsillar hypertrophy even after adjustment for age, gender, obesity, passive smoking, and physician-diagnosed wheezing requiring treatment with inhaled medications over the past year [odds ratios (95% confidence interval): 3.52 (1.54-8.06); P?tonsillar hypertrophy was a stronger predictor of habitual snoring than maternal history of AT [4.00 (1.97-8.14) vs. 2.73 (1.20-6.20)]. CONCLUSIONS: Children with parental history of AT have more frequently tonsillar hypertrophy than those without such history. Tonsillar hypertrophy mediates at least in part the association between maternal history of AT and habitual snoring in childhood. Pediatr Pulmonol. © 2013 Wiley Periodicals, Inc. PMID:23775948

Kalampouka, Efthimia; Moudaki, Aggeliki; Malakasioti, Georgia; Panaghiotopoulou-Gartagani, Polytimi; Chrousos, George; Kaditis, Athanasios G

2013-06-17

31

Expanding cerebellar horizons  

Microsoft Academic Search

Anatomical connections must underly neuronal function. A new study by Middleton and Strick shows that the cerebellum projects to the dorsal prefrontal cortex of the monkey. This could provide the basis for cerebellar modulation of cognitive processes.

Narender Ramnani; Chris Miall

2001-01-01

32

Amyotrophic cerebellar hypoplasia  

Microsoft Academic Search

Lower motor neuron degeneration, cerebellar hypoplasia, atrophy of pons, olives, and cerebellum, sclerosis of thalamus and pallidum, and deficient myelination were found in a 2-months-old baby with laryngeal paralysis, mental retardation, progressive amyotrophy, and slow nerve conduction velocity. Such changes seem characteristic of an unusual syndrome previously referred to as “cerebellar hypoplasia in Werdnig-Hoffmann disease”, or “anterior horn cell disease

G. A. León; W. D. Grover; C. A. D'Cruz

1984-01-01

33

Iridium-192 implants in the treatment of tonsillar region malignancies  

SciTech Connect

A total of 127 patients with histologically proved diagnosis of carcinoma of the tonsillar region and soft palate were treated over the past ten years utilizing interstitial iridium-192 implants. Eighty patients were treated for primary tumors and 47 patients for either recurrent or persistent tumors after definitive irradiation and/or surgery. All patients with primary tumors were treated by a combination of external megavoltage irradiation and interstitial iridium-192 implants, whereas patients with recurrent tumors were treated by interstitial implants alone. In the primary group, 95% of patients with T1 and T2 lesions and 79% with T3 and T4 lesions achieved complete local tumor control. The three-year absolute disease-free survival rate was 72%. Seventy-five percent local tumor control was obtained in patients with recurrent disease, with two-year absolute disease-free survival of 42%. Treatment-related complications such as soft-tissue necrosis or osteoradionecrosis occurred in 6% of patients in the primary group and 23% in recurrent group. This treatment regimen offers an excellent locoregional control with no significant functional or esthetic impairment. Most patients with primary lesions who fail this regimen can be salvaged by surgery or reirradiation using interstitial implants.

Puthawala, A.A.; Syed, A.M.; Gates, T.C.

1985-12-01

34

Transient "cerebellar" mutism.  

PubMed

The term "cerebellar mutism" refers to a specific disorder in which a complete but transient loss of speech, followed by dysarthria, occurs following resection of intrinsic posterior cranial fossa tumors or cerebellar hemorrhages, or upon trauma. Although it is well known that the lack of long-tract findings and cranial nerve (CN) involvement is the rule, the pathophysiology of cerebellar mutism has not been clearly elucidated. A review of the relevant literature disclosed 93 patients with this condition, the majority of these being in the pediatric age group. The neuropathological findings were as follows: 57 primitive neuroectodermal tumors (PNET), 19 astrocytomas, 10 ependymomas, 5 vascular malformations, 1 metastatic tumor, and 1 traumatic injury. The interval before the onset of mutism ranged from 0 to 168 h (mean 40.9 h). The mutism lasted from 1 to 168 days (mean 37.6 days). Subsequent dysarthria was present in 75 (80%) of the 93 patients. In this article, some specific recent illustrative reports are presented, and the concept of the role of the cerebellum in language and cognition is discussed. With these data as our point of departure, various hypotheses that have been advanced to explain the pathogenesis of this transient speech disorder are analyzed. The findings of the study suggest that the cause of the cerebellar mutism is the ischemia caused by vasospasm, as it usually developed after a latent period. PMID:9660116

Turgut, M

35

Cerebellar astrocytomas in children  

Microsoft Academic Search

Cerebellar astrocytomas, as a group, carry a more favorable prognosis than most other brain tumors, because these neoplasms generally are histologically benign and amenable to extensive resection. However, it is clear that a number of factors have an impact on prognosis. In particular, resection extent has been strongly associated with progression-free survival: patients undergoing gross total resection appear to have

Jeffrey W. Campbell; Ian E. Pollack

1996-01-01

36

Syphilitic tonsillitis presenting as an ulcerated tonsillar tumor with ipsilateral lymphadenopathy.  

PubMed

We describe a 49-year-old man who presented with a cervical mass of a week's evolution, which clinically mimicked a tumoral expansion. Physical examination showed a left cervical mass of 6 x 4 x 2 cm, associated to a left ulcerated tonsillar tumor. The presumptive diagnosis was a tonsillar cancer with lymph node involvement. An amygdalectomy and a frozen section biopsy of the cervical tumor were performed. The biopsy displayed a reactive lymphadenopathy with follicular and interfollicular hyperplasia rich in plasma cells, epithelioid areas, and an outstanding parcel fibrosis of subcapsular, interfollicular, and perifollicular distribution associated to an isolated focus of polymorphonuclear leukocytes and obliterative parietal angiovascular proliferation. The tonsil presented a similar but ulcerated process. These results suggested an infectious reactive process, probably luetic. A Warthin-Starry stain revealed spirochetes in the tonsillar ulcer. Laboratory examinations revealed a positive VDRL test and negative serology for HIV. In conclusion, a primary syphilis of the oropharyngeal tonsil with a syphilic lymphadenopathy was diagnosed. The literature about tonsillar syphilis is reviewed. PMID:17870023

Oddó, David; Carrasco, Gonzalo; Capdeville, Felipe; Ayala, María Fernanda

2007-07-24

37

High Rates of Detection of Respiratory Viruses in Tonsillar Tissues from Children with Chronic Adenotonsillar Disease  

PubMed Central

Chronic tonsillar diseases are an important health problem, leading to large numbers of surgical procedures worldwide. Little is known about pathogenesis of these diseases. In order to investigate the role of respiratory viruses in chronic adenotonsillar diseases, we developed a cross-sectional study to determine the rates of viral detections of common respiratory viruses detected by TaqMan real time PCR (qPCR) in nasopharyngeal secretions, tonsillar tissues and peripheral blood from 121 children with chronic tonsillar diseases, without symptoms of acute respiratory infections. At least one respiratory virus was detected in 97.5% of patients. The viral co-infection rate was 69.5%. The most frequently detected viruses were human adenovirus in 47.1%, human enterovirus in 40.5%, human rhinovirus in 38%, human bocavirus in 29.8%, human metapneumovirus in 17.4% and human respiratory syncytial virus in 15.7%. Results of qPCR varied widely between sample sites: human adenovirus, human bocavirus and human enterovirus were predominantly detected in tissues, while human rhinovirus was more frequently detected in secretions. Rates of virus detection were remarkably high in tonsil tissues: over 85% in adenoids and close to 70% in palatine tonsils. In addition, overall virus detection rates were higher in more hypertrophic than in smaller adenoids (p?=?0.05), and in the particular case of human enteroviruses, they were detected more frequently (p?=?0.05) in larger palatine tonsils than in smaller ones. While persistence/latency of DNA viruses in tonsillar tissues has been documented, such is not the case of RNA viruses. Respiratory viruses are highly prevalent in adenoids and palatine tonsils of patients with chronic tonsillar diseases, and persistence of these viruses in tonsils may stimulate chronic inflammation and play a role in the pathogenesis of these diseases.

Proenca-Modena, Jose Luiz; Pereira Valera, Fabiana Cardoso; Jacob, Marcos Gerhardinger; Buzatto, Guilherme Pietrucci; Saturno, Tamara Honorato; Lopes, Lucia; Souza, Jamila Mendonca; Paula, Flavia Escremim; Silva, Maria Lucia; Carenzi, Lucas Rodrigues; Tamashiro, Edwin

2012-01-01

38

Curb descent testing of suspension manual wheelchairs.  

PubMed

Manual wheelchair users are subjected to whole-body vibrations (WBV) on a regular basis as they traverse obstacles and uneven surfaces. One way users could protect themselves from secondary injuries related to WBV is by using a suspension manual wheelchair. This study investigated the ability of suspension manual wheelchairs to reduce seat accelerations during curb descents of various heights (5, 10, and 15 cm). Sixteen manual wheelchairs (four suspension, four folding, four rigid, and four rigid titanium) were tested. Suspension wheelchairs transmitted significantly lower peak seat accelerations than folding wheelchairs during the 5 cm curb descents (p = 0.048) and significantly lower frequency-weighted peak seat accelerations during the 5 and 10 cm curb descents (p = 0.03 for both heights). However, when the suspension wheelchair Quickie XTR (Sunrise Medical; Carlsbad, California) was removed from the analysis, the suspension wheelchairs were not significantly different from the nonsuspension wheelchairs. When weight was considered, the suspension wheelchairs had significantly lower peak seat accelerations than the lighter rigid wheelchairs during 5 cm curb descents (p = 0.047). While suspension manual wheelchairs offer some reduction in WBV during curb descents, their limitations should be considered when a wheelchair is selected for everyday use. PMID:18566927

Kwarciak, Andrew M; Cooper, Rory A; Fitzgerald, Shirley G

2008-01-01

39

Clinical spectrum associated with cerebellar hypoplasia  

Microsoft Academic Search

We reviewed 45 children with cerebellar hypoplasia on magnetic resonance imaging to identify clinical features associated with cerebellar hypoplasia. We then studied children presenting with any likely associated clinical feature of cerebellar hypoplasia previously observed or reported. Two hundred fifty-one children, with one or more of these features, exhibited no cerebellar hypoplasia on imaging. We compared the children with cerebellar

Evangeline Wassmer; Paul Davies; William P Whitehouse; Stuart H Green

2003-01-01

40

Treatment of cerebellar masses  

Microsoft Academic Search

Opinion statement  Cerebellar masses are a heterogenous group of conditions that can cause compression of the aqueduct or fourth ventricle, resulting\\u000a in obstructive hydrocephalus, brainstem compression, and upward\\/downward herniation as a direct result of mass effect. Untreated\\u000a lesions can be fatal in a few hours, but prompt and appropriate treatment of the mass effect can produce very good outcomes.\\u000a These patients

Mahmut Edip Gurol; Erik K. St. Louis

2008-01-01

41

Childhood Cerebellar Ataxia  

PubMed Central

Childhood presentations of ataxia, an impairment of balance and coordination caused by damage to or dysfunction of the cerebellum, can often be challenging to diagnose. Presentations tend to be clinically heterogeneous but key considerations may vary based on the child's age at onset, the course of illness, and subtle differences in phenotype. Systematic investigation is recommended for efficient diagnosis. In this review, we outline common etiologies and describe a comprehensive approach to the evaluation of both acquired and genetic cerebellar ataxia in children.

Fogel, Brent L.

2012-01-01

42

Cerebellar mutism syndrome.  

PubMed

Since 1980, a growing number of pediatric patients with mutism following posterior fossa surgery have been recognized. This syndrome typically affects children and in rare cases young adults who become mute one or two days after tumor operation but do not show disturbances of consciousness or language comprehension. The disorder persists for 1 to 4 months. The pathogenesis is still unknown. Of 21 children who underwent surgery for large posterior fossa tumors between 1991 and 1995, 6 developed cerebellar mutism. Histologically the tumors were classified as astrocytoma WHO grade I, astrocytoma WHO grade II and ependymoma WHO grade III in one case and medulloblastoma WHO grade IV in three cases. Besides the clinical course, intraoperative findings and CT or MRI data are evaluated and discussed considering possible etiological hypotheses. Our own experience and also literature reviews suggest that the lesion of the cerebellar hemispheres might be the most important one of multiple factors causing cerebellar mutism. Generally the syndrome is transient. The diagnosis should not delay adjuvant therapy in patients with a malignancy. PMID:9743960

Janssen, G; Messing-Jünger, A M; Engelbrecht, V; Göbel, U; Bock, W J; Lenard, H G

43

Evaluating and Improving Recursive Descent Parsers  

Microsoft Academic Search

Time formulas are symbolic formulas which express the execution time of a program as a function of its input data and of variables representing the time to execute individual operations (e.g., push, pop, transfer, etc.). It is shown that in many cases the time formulas for recursive descent parsers may be generated automatically by a simple inspection of the parser

Jacques Cohen; Robin Sitver; David Auty

1979-01-01

44

Research Study: Sts-1 Orbiter Descent.  

National Technical Information Service (NTIS)

The conversion of STS-1 orbiter descent data from AVE-SESAME contact programs to the REEDA system and the reduction of raw radiosonde data is summarized. A first difference program, contact data program, plot data program, and 30 second data program were ...

J. S. Hickey

1981-01-01

45

Cognitive architecture and descent with modification  

Microsoft Academic Search

Against a background of recent progress in developmental neuroscience, some of which has been taken as challenging to the modularity hypothesis of Fodor (1983), this article contrasts two competing conceptions of modularity: sui generis modularity, according to which modules are treated as independent neurocognitive entities that owe nothing to one another, and descent-with-modification modularity, according to which current cognitive modules

Gary F. Marcus

2006-01-01

46

Coping with Discrimination among Mexican Descent Adolescents  

ERIC Educational Resources Information Center

The current research is designed to explore the relationship among discrimination stress, coping strategies, and self-esteem among Mexican descent youth (N = 73, age 11-15 years). Results suggest that primary control engagement and disengagement coping strategies are positively associated with discrimination stress. Furthermore, self-esteem is…

Edwards, Lisa M.; Romero, Andrea J.

2008-01-01

47

Cerebellar astrocytoma presenting as a cerebellar hemorrhage in a child.  

PubMed

An acute cerebellar hemorrhage in a 14-year-old girl was found to be caused by bleeding that had occured in an occult cerebellar astrocytoma. Such symptomatic hemorrhage into tumors, whether of metastatic or primary brain origin, occurs rarely but must be considered in patients of all ages who present with atypical strokes of presumed hemorrhagic etiology. PMID:7188642

Vincent, F M; Bartone, J R; Jones, M Z

1980-01-01

48

Crew Procedures for Continuous Descent Arrivals Using Conventional Guidance.  

National Technical Information Service (NTIS)

This paper presents results from a simulation study which investigated the use of Continuous Descent Arrival (CDA) procedures for conducting a descent through a busy terminal area, using conventional transport-category automation. This research was part o...

D. H. Williams E. T. Lewis R. M. Oseguera-Lohr

2007-01-01

49

Immunohistological identification of B cell differentiation in human tonsillar follicles by using monoclonal antibodies.  

PubMed

Using immunoperoxidase technique and various monoclonal antibodies, B1, B2, OKT9, OKT10 and Leu-7, we investigated B cell differentiation in the tonsillar follicle. Mantle zone was stained with B1 intensely and B2 faintly. In contrast, germinal center was stained with B1, OKT10 and OKT9, and more intensely with B2. In the intermediate part of the germinal center some large cells were stained with OKT10. With OKT9 antibody, most of cells in the lymphoepithelial symbiosis and some large dendritic cells considered to be tangible body macrophages or dendritic reticulum cells in the germinal center were intensely stained. Leu-7 positive cells were localized mainly in the intermediate part of the germinal center. Stages of B cell differentiation in the tonsillar follicle were discussed, considering these results. PMID:3907016

Harabuchi, Y; Yamanaka, N; Kataura, A

1985-09-01

50

Severe congenital hypoplasia of tongue and abnormal shape of soft palate and tonsillar pillars  

Microsoft Academic Search

This paper describes an 8-year-old boy who presented with the very rare condition of congenital right-sided aglossia. The left side of tongue was hypoplastic and tethered to the floor of the mouth. The soft palate was short and almost absent on the right side with abnormal positioning of the right anterior and posterior tonsillar pillars; this situation resulted in significant

A. Rachmiel; I. T. Jackson; S. R. Sabapathy; R. A. Forté

1993-01-01

51

Efficacy of Penicillin versus Cefdinir in Eradication of Group A Streptococci and Tonsillar Flora  

PubMed Central

Core tonsillar cultures were obtained from 40 children with recurrent tonsillitis treated with either penicillin or cefdinir. Group A beta-hemolytic streptococci were isolated from 11 penicillin- and 3 cefdinir-treated (P < 0.001) patients. ?-Lactamase producers were recovered from 17 penicillin- and 3 cefdinir-treated (P < 0.01) patients. Inhibiting alpha-hemolytic streptococci were isolated less often from penicillin-treated patients than from cefdinir-treated patients.

Brook, Itzhak; Foote, Perry A.

2005-01-01

52

Spontaneous dural tear leading to intracranial hypotension and tonsillar herniation in Marfan syndrome: a case report  

PubMed Central

Background We describe the case of a 38 year old male with Marfan syndrome who presented with orthostatic headaches and seizures. Case Presentation The patient was diagnosed with Spontaneous Intracranial Hypotension secondary to CSF leaks, objectively demonstrated by MR Myelogram with intrathecal contrast. Epidural autologus blood patch was administered at the leakage site leading to significant improvement. Conclusion Our literature search shows that this is the second reported case of a Marfan patient presenting with symptomatic spontaneous CSF leaks along with tonsillar herniation.

2010-01-01

53

The Mars Exploration Rovers Descent Image Motion Estimation System  

Microsoft Academic Search

Descent image motion estimation system is the first machine-vision system for estimating lander velocity during planetary descent. Composed of sensors and software, DIMES features a descent imager, a radar altimeter, an inertial-measurement unit, and an algorithm for combining sensor measurements to estimate horizontal velocity - the speed across the planet's surface the lander travels as it descends. Although the sensors

Yang Cheng; Jay Goguen; Andrew Edie Johnson; Chris Leger; Larry Matthies; A. Miguel San Martin; Reg G. Willson

2004-01-01

54

Preeruptive Cerebellar Ataxia in Varicella  

Microsoft Academic Search

Varicella, or chicken pox, has an annual incidence of approximately 3 million cases, mainly in the pediatric population. Neurologic complications are well described and usually follow the onset of typical chicken pox lesions. We report the case of a 3-year-old boy who presented with cerebellar ataxia before the onset of chicken pox rash. He recovered without sequelae. Cerebellar ataxia is

Rick S Belcher

1996-01-01

55

Expression of Human Papillomavirus-Related Proteins and Its Clinical Implication in Tonsillar Squamous Cell Carcinoma  

PubMed Central

Background Human papillomavirus (HPV) is known to cause of oropharyngeal squamous cell carcinoma (SqCC). HPV positive SqCCs overexpress p16 and are associated with better survival. Several markers of cell cycles and apoptosis have been reported as a prognostic value. We examined the prognostic value of HPV status, p16, cyclin D1, and Bcl-2 in patients with tonsillar SqCC. Methods Tissue microarrays were constructed in 56 cases of tonsillar SqCC for which we performed an immunohistochemistry and an in situ hybridization (ISH) of the HPV. Results Of the 56 cases, 31 (55.3%) were positive for p16 and 20 (35.7%) were positive for HPV ISH. The expressions of p16, cyclin D1, and Bcl-2 were not correlated with the clinicopathologic variables including smoking status, differentiation and pT- and pN-stages. The HPV ISH positive group showed a better overall survival than the HPV negative group (p=0.04), and the p16 positive group showed a better disease free survival (DFS) than the negative group (p=0.016). Cox regression analysis showed that only p16 positivity was an independent prognostic factor for DFS (p=0.03; hazard ratio, 10.1). Conclusions Our results indicate that both p16 expression and HPV status are useful indicators for risk stratification in patients with tonsillar SqCC.

Song, Joon Seon; Kim, Min-Sik; Park, Joon Wook; Kang, Chang Suk

2012-01-01

56

Analysis and Classification of Cerebellar Malformations  

Microsoft Academic Search

BACKGROUND AND PURPOSE: Because of improved visualization of posterior fossa struc- tures with MR imaging, cerebellar malformations are recognized with increasing frequency. Herein we attempt to describe and propose a rational classification of cerebellar malformations. METHODS: MR images obtained in 70 patients with cerebellar malformations were retro- spectively reviewed. The cerebellar malformations were initially divided into those with hyp- oplasia

Sandeep Patel; A. James Barkovich

2002-01-01

57

Cerebellar involvement in executive control.  

PubMed

The cerebellum has long been considered to be mainly involved in motor function. In the last 20 years, evidence from neuroimaging studies and from investigations of patients with cerebellar lesions has shown that the cerebellum plays a role in a range of cognitive functions. While cerebellar contributions have been shown for learning and memory, the cerebellum has also been linked to higher order cognitive control processes frequently referred to as executive functions. Although it is widely accepted that the cerebellum contributes to cognitive processing, the nature of cerebellar involvement is not well understood. The present paper focuses on the role of the cerebellum in executive processing, reviewing findings derived from neuroimaging studies or from studies investigating deficits related to cerebellar dysfunction. As executive functions cannot be considered as a unitary concept, special emphasis is put on cerebellar contributions to different aspects of executive control such as working memory, multitasking or inhibition. Referring to models derived from motor control, possible mechanisms of cerebellar involvement in executive processing are discussed. Finally, methodological problems in assessing executive deficits in general and in assessing the cerebellar contribution to executive processing in particular are addressed. PMID:17786814

Bellebaum, Christian; Daum, Irene

2007-01-01

58

Visuospatial abilities in cerebellar disorders  

PubMed Central

Background: Cerebellar involvement in spatial data management has been suggested on experimental and clinical grounds. Objective: To attempt a specific analysis of visuospatial abilities in a group of subjects with focal or atrophic cerebellar damage. Methods: Visuospatial performance was tested using the spatial subtests of the WAIS, the Benton line orientation test, and two tests of mental rotation of objects—the Minnesota paper form board test (MIN) and the differential aptitude test (DAT). Results: In the Benton line orientation test, a test of sensory analysis and elementary perception, no deficits were present in subjects with cerebellar damage. In MIN, which analyses the capacity to process bidimensional complex figures mentally, and in the DAT, which is based on mental folding and manipulation of tridimensional stimuli, subjects with cerebellar damage were impaired. Conclusions: The results indicate that lesions of the cerebellar circuits affect visuospatial ability. The ability to rotate objects mentally is a possible functional substrate of the observed deficits. A comparison between visuospatial performance of subjects with focal right and left cerebellar lesions shows side differences in the characteristics of the visuospatial syndrome. Thus cerebellar influences on spatial cognition appear to act on multiple cognitive modules.

Molinari, M; Petrosini, L; Misciagna, S; Leggio, M

2004-01-01

59

Cerebellar pathology in tuberous sclerosis.  

PubMed

Cerebellar involvement in tuberous sclerosis is rare and generally nonsymptomatic. The authors describe a cerebellar tuber in a 5-year-old boy with tuberous sclerosis. A CT scan at age 2 years showed the characteristic cortical, white matter, and subependymal lesions of tuberous sclerosis. At 5 years, when the patient was symptomatic with ataxia, the CT and MRI scans revealed additionally the presence of a right cerebellar enhancing lesion with edema. A total surgical resection was undertaken. The cerebellar lesion was very firm and demonstrated marked disorganization of neuronal architecture in the cerebellar folia, with bizzare ectopic neurons in the molecular and granule cell layers and white matter, along with calcification, gliosis, and Rosenthal fiber deposition. Balloon cells with glassy, pale, eosinophilic cytoplasm were also present. There was a marked loss of myelin in the white matter, with significant vacuolation and gliosis. Electron microscopy documented abundant lysosomal inclusions, prominent rough endoplasmic reticulum and Golgi complexes, microtubules, intermediate filaments, and synaptic contacts. While there is much speculation as to the precise nature of cerebellar pathology in tuberous sclerosis, this case demonstrates conclusively that the cerebellar lesions reflect anomolous neuronal development and migration akin to supratentorial lesions and can rarely be symptomatic. PMID:9805358

Jay, V; Edwards, V; Musharbash, A; Rutka, J T

60

Adaptive filter design using recurrent cerebellar model articulation controller.  

PubMed

A novel adaptive filter is proposed using a recurrent cerebellar-model-articulation-controller (CMAC). The proposed locally recurrent globally feedforward recurrent CMAC (RCMAC) has favorable properties of small size, good generalization, rapid learning, and dynamic response, thus it is more suitable for high-speed signal processing. To provide fast training, an efficient parameter learning algorithm based on the normalized gradient descent method is presented, in which the learning rates are on-line adapted. Then the Lyapunov function is utilized to derive the conditions of the adaptive learning rates, so the stability of the filtering error can be guaranteed. To demonstrate the performance of the proposed adaptive RCMAC filter, it is applied to a nonlinear channel equalization system and an adaptive noise cancelation system. The advantages of the proposed filter over other adaptive filters are verified through simulations. PMID:20659864

Lin, Chih-Min; Chen, Li-Yang; Yeung, Daniel S

2010-07-01

61

Tonsillar ectopia in idiopathic scoliosis: does it play a role in the pathogenesis and prognosis or is it only an incidental finding?  

Microsoft Academic Search

BACKGROUND: There is an ongoing controversy about the significance of tonsillar ectopia among patients with idiopathic scoliosis (IS). AIM: To find out if tonsillar ectopia occurs more frequently among patients with IS and if it plays any etiological or prognostic role in IS. STUDY DESIGN: Retrospective study. METHODS: Retrospective analysis of 155 consecutive spine MRIs (79 patients with IS and

Kasim Abul-Kasim; Angelica Overgaard; Magnus K Karlsson; Acke Ohlin

2009-01-01

62

[Bilateral tonsillar hypertrophy as the first manifestation of B cell-small lymphocytic lymphoma with interfolicular pattern].  

PubMed

B-cell small lymphocytic lymphoma typically involves nodal or extranodal tissues as a diffuse proliferation with proliferation centers (pseudofollicules) obliterating normal architecture. But there are unusual patterns of involvement including interfollicular pattern that can be difficult to recognize histologically and probably represent partial or early involvement by neoplasm. Tonsillar lymphoma usually presents either as a unilaterally enlarged palatine tonsil or as an ulcerative and fungating lesion over the tonsillar area. Most lymphomas that involve the tonsil are diffuse large B cell lymphomas and primary low-grade lymphomas are exceptional. We present a primary B-cell small lymphocytic lymphoma affecting palatine tonsils with interfollicular pattern in a 54 year-old man that clinically presented with symmetric / bilateral tonsillar enlargement and sleep apnea. PMID:20696111

Soria-Céspedes, Danny; Baquera-Heredia, Javier; Pardo, Adolfo; Ortiz-Hidalgo, Carlos

63

Speech prosody in cerebellar ataxia  

NASA Astrophysics Data System (ADS)

The present study sought an acoustic signature for the speech disturbance recognized in cerebellar degeneration. Magnetic resonance imaging was used for a radiological rating of cerebellar involvement in six cerebellar ataxic dysarthric speakers. Acoustic measures of the [pap] syllables in contrastive prosodic conditions and of normal vs. brain-damaged patients were used to further our understanding both of the speech degeneration that accompanies cerebellar pathology and of speech motor control and movement in general. Pair-wise comparisons of the prosodic conditions within the normal group showed statistically significant differences for four prosodic contrasts. For three of the four contrasts analyzed, the normal speakers showed both longer durations and higher formant and fundamental frequency values in the more prominent first condition of the contrast. The acoustic measures of the normal prosodic contrast values were then used as a model to measure the degree of speech deterioration for individual cerebellar subjects. This estimate of speech deterioration as determined by individual differences between cerebellar and normal subjects' acoustic values of the four prosodic contrasts was used in correlation analyses with MRI ratings. Moderate correlations between speech deterioration and cerebellar atrophy were found in the measures of syllable duration and f0. A strong negative correlation was found for F1. Moreover, the normal model presented by these acoustic data allows for a description of the flexibility of task- oriented behavior in normal speech motor control. These data challenge spatio-temporal theory which explains movement as an artifact of time wherein longer durations predict more extreme movements and give further evidence for gestural internal dynamics of movement in which time emerges from articulatory events rather than dictating those events. This model provides a sensitive index of cerebellar pathology with quantitative acoustic analyses.

Casper, Maureen

64

Redistribution of crossed cerebellar diaschisis  

SciTech Connect

Crossed cerebellar diaschisis refers to a functional decrease in blood flow to the cerebellar hemisphere contralateral to the infarcted or ischemic cerebral hemisphere. This phenomenon can be depicted using PET as well as using SPECT. This condition, seen on early I-123 IMP brain scans, can show redistribution on the three hour delayed scan, presumably due to normal non-specific amine receptor sites of the affected cerebellum. One such case is reported.

Kim, S.M.; Park, C.H.; Intenzo, C.M.; Bell, R.

1989-04-01

65

CD44 and hyaluronan-dependent rolling interactions of lymphocytes on tonsillar stroma  

PubMed Central

Little is known about how lymphocytes migrate within secondary lymphoid organs. Stromal cells and their associated reticular fibers form a network of fibers that radiate from high endothelial venules to all areas of the lymph node and may provide a scaffold for lymphocyte migration. We studied interactions of lymphocytes with cultured human tonsillar stromal cells and their extracellular matrix using shear stress to distinguish transient interactions from firm adhesion. Tonsillar lymphocytes and SKW3 T lymphoma cells tethered and rolled on monolayers of cultured tonsillar stromal cells and their matrix. A significant proportion of these rolling interactions were independent of divalent cations and were mediated by CD44 binding to hyaluronan, as shown by inhibition with mAb to CD44, soluble hyaluronan, as hyaluronidase treatment of the substrate, and O-glycoprotease treatment of the rolling cells. O-glycoprotease treatment of the substrate also blocked binding completely to stromal matrix and partially to stromal monolayers. SKW3 cells tethered and rolled on plastic-immobilized hyaluronan, confirming the specificity of this interaction. By contrast, monolayers of resting or stimulated human umbilical vein endothelial cells failed to support CD44- and hyaluronan-dependent rolling. SKW3 cells added under flow conditions to frozen sections of human tonsil bound and rolled along reticular fibers in the presence of EDTA. Rolling was blocked by either CD44 mAb or hyaluronan. We propose that lymphocytes migrating through secondary lymphoid organs may use CD44 to bind to hyaluronan immobilized on stromal cells and reticular fibers.

1996-01-01

66

Molecular Mapping to Species Level of the Tonsillar Crypt Microbiota Associated with Health and Recurrent Tonsillitis  

PubMed Central

The human palatine tonsils, which belong to the central antigen handling sites of the mucosal immune system, are frequently affected by acute and recurrent infections. This study compared the microbiota of the tonsillar crypts in children and adults affected by recurrent tonsillitis with that of healthy adults and children with tonsillar hyperplasia. An in-depth 16S rRNA gene based pyrosequencing approach combined with a novel strategy that included phylogenetic analysis and detection of species-specific sequence signatures enabled identification of the major part of the microbiota to species level. A complex microbiota consisting of between 42 and 110 taxa was demonstrated in both children and adults. This included a core microbiome of 12 abundant genera found in all samples regardless of age and health status. Yet, Haemophilus influenzae, Neisseria species, and Streptococcus pneumoniae were almost exclusively detected in children. In contrast, Streptococcus pseudopneumoniae was present in all samples. Obligate anaerobes like Porphyromonas, Prevotella, and Fusobacterium were abundantly present in children, but the species diversity of Porphyromonas and Prevotella was larger in adults and included species that are considered putative pathogens in periodontal diseases, i.e. Porphyromonas gingivalis, Porphyromonas endodontalis, and Tannerella forsythia. Unifrac analysis showed that recurrent tonsillitis is associated with a shift in the microbiota of the tonsillar crypts. Fusobacterium necrophorum, Streptococcus intermedius and Prevotella melaninogenica/histicola were associated with recurrent tonsillitis in adults, whereas species traditionally associated with acute tonsillitis like pyogenic streptococci and Staphylococcus aureus were scarce. The findings suggest that recurrent tonsillitis is a polymicrobial infection in which interactions within consortia of taxa play an etiologic role. The study contributes to the human microbiome data, to the understanding of the etiology of infections affecting the tonsils, and forms a basis for further insight into the consequences of the intense microbe-host interactions that take place in the tonsils.

Jensen, Anders; Fago-Olsen, Helena; S?rensen, Christian Hjort; Kilian, Mogens

2013-01-01

67

Effects of guidelines on adeno-tonsillar surgery on the clinical behaviour of otorhinolaryngologists in Italy  

PubMed Central

Background Several guidelines on adeno-tonsillar disease have been proposed in recent years and some discrepancies in relation both to clinical manifestations and indications for surgical treatment have emerged. The aim of the study was to verify what influence (adeno)-tonsillectomy guidelines have had on the clinical behaviour of ENT specialists in Italy. Our study is a retrospective and multi-centre case series with chart review. Methods The survey involved 14,770 children, aged between the ages of 2 and 11, who had undergone adeno-tonsillar surgery between 2002 and 2008 in fourteen Italian tertiary and secondary referral centres. Anova test was used for the statistical analysis, assuming p < 0.05 as the minimum statistical significance value. Results The frequency of adeno-tonsillar surgeries did not change significantly (p>0.05) during the study period and following the Italian policy document publication. Overall, adeno-tonsillectomy was the most frequent intervention (64.1%), followed by adenoidectomy (31.1%) and tonsillectomy (4.8%). The indications for surgery did not change significantly for each of the operations (p>0.05), with the exception of adeno-tonsillectomy in case of feverish episodes due to acute recurrent tonsillitis ? 5 without nasal obstruction (decreased p= 0.010) , even when the feverish episodes due to acute recurrent tonsillitis were < 5 over the last year. Nasal obstruction was associated with feverish episodes due to acute recurrent tonsillitis in 65.2% of operated cases, while otitis media had been diagnosed in 43.3% of the patients studied. Conclusions The recommendations first developed in Italy in a 2003 policy document and then resumed in guidelines in 2008, were not implemented by ENT units involved in the survey. The study highlights the fact that the indications for adeno-tonsillar operations are based on the overall clinical presentation (comorbidity) rather than on a single symptom. Guidelines are necessary to give coherent recommendations based on both the findings obtained through randomized controlled trials and the data collected from observational studies.

2013-01-01

68

[An adult case of cerebellar mutism after removal of cerebellar hematoma].  

PubMed

Cerebellar mutism is a well documented complication of posterior fossa tumor surgery in children. But only one case presenting with cerebellar mutism after removal of a cerebellar hematoma in adults was reported previously. We present 64-year-old male developing cerebellar mustism after surgery for hypertensive cerebellar hemorrhage. A cerebellar hematoma was located in the right side dentate nucleus and cerebellar peduncle dominantly not extending to the cerebellar vermis. During the period of cerebellar mutism, single photon emission computed tomography revealed a decrease in the contralateral temporo-parietal cerebral blood flow. Cerebellar mutism in this case may be associated with the low blood flow in the contralateral supplementary motor cortex owing to injury to the dentate-thalamo-cortical pathway at the dentate nucleus and cerebellar peduncle. The relevant literature is reviewed. PMID:11424360

Kawai, H; Ohta, F; Matsumoto, Y; Yamamoto, Y

2001-05-01

69

African Descent and Glaucoma Evaluation Study (ADAGES)  

PubMed Central

Objective To investigate differences in visual function between the healthy eyes of people of African (AD) and European descent (ED). Methods Visual function was assessed in 393 AD and 367 ED participants selected from the African Descent and Glaucoma Evaluation Study and the Diagnostic Innovations in Glaucoma Study. Participants had normal appearance of the optic disc and intraocular pressure of less than 22 mm Hg. Each participant had 2 reliable 24-2 standard automated perimetry tests, and most had short-wavelength automated perimetry and frequency-doubling technology tests. The generalized estimating equation was used to adjust for intereye correlations. Results were adjusted for age, vertical cup-disc ratio, disc size, central corneal thickness, and presence of high blood pressure. Results The AD participants were younger (mean [SD] age, 46.2 [13.2] years) than the ED participants (age, 49.5 [16.6] years) (P=.003). The AD participants had worse mean deviation and pattern standard deviation and more points triggered as abnormal on the total and pattern deviation plots compared with ED participants on all tests (P<.05). A larger percentage of AD participants had confirmed abnormal glaucoma hemifield test results on standard automated perimetry only. Conclusions People of AD have significantly worse performance than people of ED on all tests of visual function. Additional research using longitudinal data is needed to determine the cause of these small but significant ancestry differences in visual function. Trial Registration clinicaltrials.gov Identifier: NCT00221923

Racette, Lyne; Liebmann, Jeffrey M.; Girkin, Christopher A.; Zangwill, Linda M.; Jain, Sonia; Becerra, Lida M.; Medeiros, Felipe A.; Bowd, Christopher; Weinreb, Robert N.; Boden, Catherine; Sample, Pamela A.

2010-01-01

70

African Descent and Glaucoma Evaluation Study (ADAGES)  

PubMed Central

Objective To define differences in optic disc, retinal nerve fiber layer, and macular structure between healthy participants of African (AD) and European descent (ED) using quantitative imaging techniques in the African Descent and Glaucoma Evaluation Study (ADAGES). Methods Reliable images were obtained using stereoscopic photography, confocal scanning laser ophthalmoscopy (Heidelberg retina tomography [HRT]), and optical coherence tomography (OCT) for 648 healthy subjects in ADAGES. Findings were compared and adjusted for age, optic disc area, and reference plane height where appropriate. Results The AD participants had significantly greater optic disc area on HRT (2.06 mm2; P<.001) and OCT (2.47 mm2; P<.001) and a deeper HRT cup depth than the ED group (P<.001). Retinal nerve fiber layer thickness was greater in the AD group except within the temporal region, where it was significantly thinner. Central macular thickness and volume were less in the AD group. Conclusions Most of the variations in optic nerve morphologic characteristics between the AD and ED groups are due to differences in disc area. However, differences remain in HRT cup depth, OCT macular thickness and volume, and OCT retinal nerve fiber layer thickness independent of these variables. These differences should be considered in the determination of disease status.

Girkin, Christopher A.; Sample, Pamela A.; Liebmann, Jeffrey M.; Jain, Sonia; Bowd, Christopher; Becerra, Lida M.; Medeiros, Felipe A.; Racette, Lyne; Dirkes, Keri A.; Weinreb, Robert N.; Zangwill, Linda M.

2010-01-01

71

Small lymphocytic lymphoma obscuring microscopic tonsillar squamous cell carcinoma: an unknown occurrence with a known primary.  

PubMed

Head and neck squamous cell carcinoma (HNSCC) often presents with cervical lymph node metastases and at times the primary tumor cannot be identified despite extensive workup. Lymphoma is the second most common neoplasm in the head and neck region but is seldom synchronous with HNSCC and rarely involves regional mucosal sites. We report herein a rare occurrence of tonsillar involvement by small lymphocytic lymphoma (SLL) incidentally detected during the workup for a cervical lymph node SCC metastasis of a 52-year-old non-smoker male. The microscopic human papillomavirus-positive SCC involving the tonsillar surface and crypts was obscured by SLL leading to the initial designation of 'unknown primary'. The occult HNSCC are likely explained by small tumor size, quality and quantity of sampling, thoroughness of endoscopic, radiological and pathological assessment or a combination of the above. The coexistence of another tumor such as lymphoma has not yet been reported as a confounding factor in the workup for cervical SCC metastasis. Since oropharyngeal SCC can be very small and Waldeyer's ring is a common site for lymphoma involvement, identification of such rare collision tumors requires pathologists' awareness, extensive sampling and occasionally ancillary studies for the accurate diagnosis and staging essential for the correct management. PMID:21120710

Minca, Eugen C; Popat, Saurin R; Chadha, Manpreet K; Merzianu, Mihai

2010-12-01

72

[Cerebellar schistomiasis. A case report].  

PubMed

Schistomiasis or bilharziosis remains an endemic parasitic disease in many countries world wide. Urogenital, intestinal and hepatic symptoms are common. The brain is exceptionally involved and very few cases have been described in the literature. We report the case of a 35-Year-old male with a history of hematuria and bladder disorders, who developed signs of intracranial hypertension and a cerebellar syndrome over a period of one Month. Brain MRI disclosed a cerebellar lesion and a pelvic CT scan revealed a bladder tumor. Treatment consisted in a ventriculo-peritoneal shunt and corticosteroid therapy. Cystoscopy was performed for total resection of the bladder lesion. Histopathology confirmed the diagnosis of schistomiasis. Surgery was also performed to approach the cerebellar lesion. Histopathology showed the inflammatory nature of the lesion. The patient was given an antiparasitic treatment. Clinical and radiological radiological manifestations regressed. PMID:15097923

Ibahioin, K; Chellaoui, A; Lakhdar, A; Hilmani, S; Naja, A; Sami, A; Achouri, M; Ouboukhlik, A; El Kamar, A; El Azhari, A

2004-03-01

73

A class of coordinate descent methods for multiuser detection  

Microsoft Academic Search

A class of coordinate descent methods is proposed for the joint detection of binary symbols of K users in a synchronous correlated waveform multiple-access (CWMA) channel with Gaussian noise. We consider the detection problem as one of optimizing a quadratic objective function with binary constraints on decision variables. The proposed coordinate descent methods, while still maintaining a low computational complexity,

J. Luo; G. Levchuk; K. Pattipati; P. Willett

2000-01-01

74

ASCENT AND DESCENT FOR FINITE SEQUENCES OF COMMUTING ENDOMORPHISMS  

Microsoft Academic Search

Homological techniques involving the Koszul complex are used to dene and explore two invariants, ascent and descent, for a nite sequence of commuting endomorphism of a mod- ule. It is shown in particular that, as in the case of a single endomorphism, if ascent and descent are both nite then they are equal, and that this niteness condition is equivalent

Luzius Grunenfelder

1999-01-01

75

A learning method of fuzzy inference rules by descent method  

Microsoft Academic Search

The authors propose a learning method for fuzzy inference rules by a descent method. From input-output data gathered from specialists, the inference rules expressing the input-output relation of the data are obtained automatically. The membership functions in the antecedent part and the real number in the consequent part of the inference rules are tuned by means of the descent method.

Hiroyoshi NOMURA; I. Hayashi; N. Wakami

1992-01-01

76

Investigating Common Descent: Formulating Explanations and Models  

NSDL National Science Digital Library

This activity has students formulate explanations and models that simulate structural and biochemical data as they investigate the misconception that humans evolved from apes. Students should recognize that present-day species evolved from earlier species and the relatedness of organisms is the result of common ancestry. They will also discover that similarities among existing organisms provide evidence for evolution, anatomical similarities of living things reflect common ancestry, and all life forms use the same basic DNA building blocks. Basic concepts also include the fact that scientists pose, test, and revise multiple hypotheses to explain what they observe, our understanding of life through time is based upon multiple lines of evidence, the similarity of DNA nucleotide sequences can be used to infer the degree of kinship between species, and anatomical evidence is also used to infer lines of descent. This site includes a list of materials and all information required for this activity.

77

Culturing mouse cerebellar granule neurons.  

PubMed

The cerebellum plays an important role in motor control, motor skill acquisition, memory and learning among other brain functions. In rodents, cerebellar development continues after birth, characterized by the maturation of granule neurons. Cerebellar granule neurons (CGNs) are the most abundant neuronal type in the central nervous system, and they provide an excellent model for investigating molecular, -cellular, and physiological mechanisms underlying neuronal development as well as neural circuitry linked to behavior. Here we describe a procedure to isolate and culture CGNs from postnatal day 6 mice. These cultures can be used to examine numerous aspects of CGN differentiation, electrophysiology, and function. PMID:23681616

Selvakumar, Tharakeswari; Kilpatrick, Daniel L

2013-01-01

78

African descents are more sensitive than European descents to the antitumor compounds ?-hederin and kalopanaxsaponin I.  

PubMed

?-Hederin, a natural triterpene saponin and its derivative kalopanaxsaponin I (ksI) exhibit cytotoxicity against various cancer cell lines and IN VIVO tumors. We studied the genetic variants contributing to the activity of these two anticancer compounds. Cell lines derived from 30 trios of European descent (Centre d'Etude du Polymorphisme Human, CEPH; CEU) and 30 trios of African descent (Yoruban, YRI) were used. Cytotoxicity was determined as inhibition of cell growth at increasing concentrations of ?-hederin or ksI for 24?h. In comparison to the European, the Yoruban populations revealed a higher sensitivity to ?-hederin and to ksI that can be attributed to several unique SNPs. These SNPs are located near 111 and 130 genes in the European and the Yoruban populations, respectively, raising the possibility that some of these genes contribute to the differential sensitivity to these compounds. PMID:20577945

Feller, Geva; Kugel, Aleksandra; Moonshine, Dana; Chalifa-Caspi, Vered; Scholz, Martin; Prüfer, Dirk; Rabinski, Tatiana; Müller, Kai J; Ofir, Rivka

2010-06-24

79

A theory of cerebellar function  

Microsoft Academic Search

A comprehensive theory of cerebellar function is presented, which ties together the known anatomy and physiology of the cerebellum into a pattern -recognition data processing system. The cerebellum is postulated to be functionally and structurally equivalent to a modification of the classical Perceptron pattern -classification device. It is suggested that the mossy fiber -+ granule cell -+ Golgicell input network

JAMES S. ALBUS

1971-01-01

80

Linking oscillations in cerebellar circuits  

PubMed Central

In many neuroscience fields, the study of local and global rhythmicity has been receiving increasing attention. These network influences could directly impact on how neuronal groups interact together, organizing for different contexts. The cerebellar cortex harbors a variety of such local circuit rhythms, from the rhythms in the cerebellar cortex per se, or those dictated from important afferents. We present here certain cerebellar oscillatory phenomena that have been recorded in rodents and primates. Those take place in a range of frequencies: from the more known oscillations in the 4–25 Hz band, such as the olivocerebellar oscillatory activity and the granule cell layer oscillations, to the more recently reported slow (<1 Hz oscillations), and the fast (>150 Hz) activity in the Purkinje cell layer. Many of these oscillations appear spontaneously in the circuits, and are modulated by behavioral imperatives. We review here how those oscillations are recorded, some of their modulatory mechanisms, and also identify some of the cerebellar nodes where they could interact. A particular emphasis has been placed on how these oscillations could be modulated by movement and certain neuropathological manifestations. Many of those oscillations could have a definite impact on the way information is processed in the cerebellum and how it interacts with other structures in a variety of contexts.

Courtemanche, Richard; Robinson, Jennifer C.; Aponte, Daniel I.

2013-01-01

81

[Cerebellar infarctions and their mechanisms].  

PubMed

Cerebellar infarcts have been neglected for a long time and are now shown well by CT and especially MRI. Some infarcts involve the full territory supplied by a cerebellar artery. They are frequently complicated by edema with brain stem compression and supratentorial hydrocephalus, requiring at times emergency surgery, and are often accompanied by other medullary, medial pontine, mesencephalic, thalamic and occipital infarcts. On the other hand, partial territory infarcts are usually confined to the cerebellum and have a benign outcome with total recovery or minimal disability. They are more common than full territory infarcts. However, clinical presentations are similar to those full territory infarcts, differing mainly by the lack of drowsiness or unconsciousness. The main symptoms are vertigo, headache, vomiting, unsteadiness of gait and dysarthria. Signs include ipsilateral limb dysmetria, ipsilateral axial lateropulsion, ataxia and dysarthria. Vertigo is more severe and rotary in posterior inferior cerebellar artery territory infarcts, whereas dysarthria and ataxia are prominent in superior cerebellar artery territory infarcts. A few brain stem signs are sometimes added. In these territorial cerebellar infarcts, cardioembolism is the most common cause. Atherosclerotic occlusion comes next, involving the intracranial part of the vertebral artery and, less frequently, the lower basilar artery, both locations inaccessible to surgery. Other causes are artery to artery embolism from a vertebral artery origin stenosis, or the aortic arch, in situ intracranial branch atherosclerotic occlusion, and vertebral artery dissection. Border zone cerebellar infarcts occur in one third of the cases. They are small cortical or deep infarcts. They have the same symptoms and signs as territorial infarcts except for more frequent postural symptoms occurring over days, weeks or months after the ischemic event. The infarcts mainly have a thromboembolic mechanism, and sometimes have a hemodynamic mechanism: 1) focal cerebellar hypoperfusion due to large artery occlusive disease in more than half the cases, 2) small or end (pial) artery disease due to hypercoagulable state (thrombocythemia, polycythemia, hypereosinophilia, disseminated intravascular coagulation), arteritis or intracranial atheroma, and 3) rarely systemic hypotension due to cardiac arrest. PMID:8091085

Amarenco, P

1993-01-01

82

Treatment of a patient with glossopharyngeal neuralgia by the anterior tonsillar pillar method.  

PubMed

We describe the case of a 65-year-old patient with glossopharyngeal neuralgia. Pain was triggered by swallowing, yawning, or cold food. We used the anterior tonsillar pillar method for the injection of drugs; a relatively new glossopharyngeal nerve (GPN) block which was described by Benumof (Anesthesiology 1991;75:1094-1096). Performing this GPN block, daily levobupivacaine (Chirocaine® 5 mg/ml) and oral amitriptyline (Laroxyl® 10 mg) were given, as well as methylprednisolone acetate injectable suspension (Depo-Medrol® 40 mg/ml) once only at the beginning of the treatment. A 0-10 point visual analogue scale was used daily to evaluate the pain. Pain was successfully controlled with a steroid added to the GPN block and orally administered tricyclic antidepressant. We think that this treatment is effective for glossopharyngeal neuropathy and could be of interest to pain management physicians. PMID:21468360

Isbir, Cemil Ahmet

2011-01-21

83

Local Descent Direction Vector Based Differential Evolution for Multiobjective Optimization  

NASA Astrophysics Data System (ADS)

Differential Evolution (DE) is an effective optimization method for global continuous optimization problems. Recently, we developed Local Descent Direction Vector Based Differential Evolution (LDDVDE) which uses local descent direction vectors based on the operation vectors in order to improve local search performance of DE. In this paper, we extend LDDVDE to multiobjective optimization problems. We adopt Hyper-Volume indicator to order the operation vectors to make the local descent direction vectors for the case of multiobjective optimization problems. The effectiveness of the proposed method is confirmed through some numerical experiments for typical benchmark problems.

Kamiyama, Daichi; Tamura, Kenichi; Yasuda, Keiichiro

84

Cerebellar mutism in pediatric acute disseminated encephalomyelitis.  

PubMed

Acute disseminated encephalomyelitis is a demyelinating process affecting multiple areas of the central nervous system, frequently including the cerebellum. Cerebellar insult may lead to absence of speech or cerebellar mutism. Cerebellar mutism often occurs in young children after posterior fossa tumor resection, and generally appears as part of a larger subset of neurobehavioral signs and personality changes known as posterior fossa syndrome. Information on the impact of widespread cerebellar involvement on speech production, behavior, and long-term outcomes in acute disseminated encephalomyelitis is limited. We describe cases of acute disseminated encephalomyelitis with predominantly cerebellar involvement, with specific attention to cerebellar mutism. We conducted a retrospective chart review of children diagnosed with acute disseminated encephalomyelitis between 2005-2009 at a pediatric multiple sclerosis and demyelinating disorders clinic. Of 19 patients diagnosed with acute disseminated encephalomyelitis, six (32%) manifested primary cerebellar involvement. Of these six, four (67%) exhibited acute language disturbance, with three (50%) exhibiting mutism. The three patients with cerebellar mutism experienced protracted speech and language deficits after follow-ups from 6 months to 4 years. Widespread cerebellar involvement in acute disseminated encephalomyelitis may result in cerebellar mutism, in addition to persistent neurocognitive and behavioral problems. PMID:20304329

Parrish, Joy B; Weinstock-Guttman, Bianca; Yeh, E Ann

2010-04-01

85

Challenge of Mars EDL (Entry, Descent, and Landing).  

National Technical Information Service (NTIS)

This slide presentation reviews the some of the challenges of Martian atmospheric entry, descent and landing (EDL) on the surface of Mars. It reviews some of the technological difficulties, and some solutions that are being developed for future unmanned m...

R. Sostaric

2010-01-01

86

14 CFR 31.19 - Performance: Uncontrolled descent.  

Code of Federal Regulations, 2013 CFR

...be determined for the most critical uncontrolled descent that can result from any single failure of the heater assembly, fuel cell system, gas value system, or maneuvering vent system, or from any single tear in the balloon envelope between...

2013-01-01

87

Testicular descent: INSL3, testosterone, genes and the intrauterine milieu  

Microsoft Academic Search

Complete testicular descent is a sign of, and a prerequisite for, normal testicular function in adult life. The process of testis descent is dependent on gubernacular growth and reorganization, which is regulated by the Leydig cell hormones insulin-like peptide 3 (INSL3) and testosterone. Investigation of the role of INSL3 and its receptor, relaxin-family peptide receptor 2 (RXFP2), has contributed substantially

Katharina M. Main; Jorma Toppari; Niels E. Skakkebćk; Katrine Bay

2011-01-01

88

Cerebellar mutism--report of four cases.  

PubMed

The aim of the present study was to investigate the manifestations of mutism after surgery in children with cerebellar tumors. Speech impairment following cerebellar mutism in children was investigated based on standardized acoustic speech parameters and perceptual criteria. Mutistic and non-mutistic children after cerebellar surgery as well as orthopedic controls were tested pre-and postoperatively. Speech impairment was compared with the localization of cerebellar lesions (i. e. affected lobules and nuclei). Whereas both control groups showed no abnormalities in speech and behavior, the mutistic group could be divided into children with dysarthria in post mutistic phase and children with mainly behavioral disturbances. In the mutistic children involvement of dentate and fastigial nuclei tended to be more frequent and extended than in the nonmutistic cerebellar children. Cerebellar mutism is a complex phenomenon of at least two types. Dysarthric symptoms during resolution of mutism support the anarthria hypothesis, while mainly behavioral changes suggest an explanation independent from speech motor control. PMID:15316801

Ozimek, A; Richter, S; Hein-Kropp, C; Schoch, B; Gorissen, B; Kaiser, O; Gizewski, E; Ziegler, W; Timmann, D

2004-08-01

89

Nonsurgical cerebellar mutism (anarthria) in two children.  

PubMed

Cerebellar mutism (anarthria) is a well-described complication of posterior fossa tumor resection. It is accompanied by a characteristic behavior including irritability and autistic features. This syndrome is typically reversible within days to months. Underlying pathophysiology is unknown. We describe two children who presented with a similar clinical finding after nonsurgical cerebellar involvement, hemolytic-uremic syndrome in one and cerebellitis in the other. Postmortem pathologic findings in the first patient indicated cerebellar ischemic necrosis. Single-photon emission computed tomography in the second patient revealed diffuse cerebellar hypoperfusion with no supratentorial abnormalities, refuting a phenomenon of diaschisis between cerebellar and frontal connections. These findings confirm that this clinical syndrome may occur in a nonsurgical, nontraumatic context. They are consistent with recent integrative hypotheses explaining cerebellar anarthria. PMID:12657422

Mewasingh, Leena D; Kadhim, Hazim; Christophe, Catherine; Christiaens, Florence J; Dan, Bernard

2003-01-01

90

Gait adaptations to different paths of stair descent.  

PubMed

Gait characteristics during stair descent have been characterized for a straight descent path; however, pedestrians are likely to encounter a variety of staircase designs that allow one to descend at an angle (i.e. an oblique or monumental staircase). The purpose of this study was to determine the temporospatial lower limb joint kinematics differences between descending a staircase on straight versus oblique descent paths. Sixteen subjects (8 males, 8 females) descended a staircase under three different conditions: straight descent and at a 25° and 45° angle compare to the straight path. Cycle time, cadence, speed, step width, and step length were significantly affected by descent angle, while the proportion of the cycle dedicated to the stance and swing phases remained constant over the descent paths. Peak knee flexion angle increased by approximately 2.5° in the 45° condition compared to the 0° condition (p=0.0044); however, the remainder of the time series was unchanged. A decreased step width and increased step length occurred to allow the foot to sufficiently clear the steps. Changes in the temporospatial variables, hip joint angle and a constant stance/swing proportion demonstrates that these adaptations may be made to maintain characteristics of the gait cycle and prevent subjects from adopting an unfamiliar gait pattern. PMID:23583606

Gallagher, Kaitlin M; Vandenbussche, Jessica; Callaghan, Jack P

2013-04-11

91

Cognitive Impairments in Cerebellar Infarcts  

Microsoft Academic Search

The effects of the cerebellum on cognitive functions (CF) are poorly known and inadequately studied. Neurological, neuropsychological, and neuroimaging studies were performed on 25 non-random patients (14 female, 11 male, mean age 51.8 ± 18.0 years) with isolated cerebellar infarcts. Cognitive impairments (CI) were seen in 22 patients (88%). These included impairments of attention, planning, control, abstract thought, memory, and

L. A. Kalashnikova; Yu. V. Zueva; O. V. Pugacheva; N. K. Korsakova

2005-01-01

92

Bilateral in utero cerebellar infarction.  

PubMed

We report a case of complete bilateral cerebellar infarction diagnosed in utero by routine prenatal ultrasound and magnetic resonance imaging in a 26-week-old fetus. This posterior fossa ischemic stroke with secondary hemorrhage caused transient obstructive hydrocephalus and likely occurred subsequent to vertebrobasilar artery thrombosis. Such posterior fossa ischemic insults diagnosed in utero are rare with scarce clinical reports. The serial imaging characteristics, clinical, and developmental implications of this case are reviewed. PMID:21266324

Ansari, Safdar A; Hunter, Jill V; Nassif, Lisa M; Clark, Gary D; Ramocki, Melissa B

2011-01-24

93

Setup deviations in wedged pair irradiation of parotid gland and tonsillar tumors, measured with an electronic portal imaging device  

Microsoft Academic Search

The first aim of this study was to quantify estimated translational setup deviations of patients treated with a wedged pair of oblique beams for parotid gland and tonsillar tumors, using portal imaging. The second aim was to design an off-line setup verification procedure, to improve the setup accuracy, if necessary. Thirty-one patients were treated with two conformal fields (anterior-oblique and

A. Bel; R. Keus; R. E. Vijlbrief; J. V. Lebesque

1995-01-01

94

Carcinoma of the tonsillar fossa: A nonrandomized comparison of irradiation alone or combined with surgery: Long-term results  

Microsoft Academic Search

The results of therapy are reported in 296 patients with histologically proven epidermoid carcinoma of the tonsillar fossa; 127 were treated with irradiation alone (5,500 to 7,000 cGy), 133 with preoperative radiotherapy (2,000 to 3,000 cGy) or were initially planned for preoperative irradiation but treated with radiotherapy alone, and 36 with postoperative irradiation (5,000 to 6,000 cGy). The operation in

Carlos A. Perez; Thomas Carmichael; Venkata R. Devineni; Joseph R. Simpson; J. Frederickson; Donald Sessions; Gershon Spector; Barbara Fineberg

1991-01-01

95

Cerebellar mutism syndrome and its relation to cerebellar cognitive and affective function: Review of the literature.  

PubMed

Tumors of the cerebellum and brainstem account for half of all brain tumors in children. The realization that cerebellar lesions produce clinically relevant intellectual disability makes it important to determine whether neuropsychological abnormalities occur in long-term survivors of pediatric cerebellar tumors. Little is known about the neurobehavioral sequale resulting specifically from the resection of these tumors in this population. We therefore reviewed neuropsychological findings associated with postoperative cerebellar mutism syndrome and discuss the further implications for cerebellar cognitive function. PMID:20436742

Yildiz, Ozlem; Kabatas, Serdar; Yilmaz, Cem; Altinors, Nur; Agaoglu, Belma

2010-01-01

96

Relationship of the CD5 B cell to human tonsillar lymphocytes that express autoantibody-associated cross-reactive idiotypes.  

PubMed Central

We examined human tonsillar B cells for expression of autoantibody heavy-chain or kappa light-chain cross-reactive idiotypes (CRIs), respectively defined by murine MAbs G6 or 17.109. We find 17.109 or G6 each specifically binds a subpopulation of B cells, respectively reacting with 3.8 +/- 3% (mean +/- SD) or 2.0 +/- 1.2% of all tonsillar lymphocytes. Cells reactive with both 17.109 and G6 comprise only 0.4 +/- 0.3% of tonsillar lymphocytes. Although each tested specimen had 17.109-positive cells, 2 of 19 tonsils (11%) did not have any G6-reactive cells. We find that CRI-positive cells and CD5 B cells both co-express slgD but fail to bind peanut agglutinin or MAbs specific for CD10, indicating that both cell types reside in the mantle zones of secondary B cell follicles. However, less than half of the B cells bearing one or both of these CRIs express detectable levels of CD5. Nevertheless, we find that G6-reactive lymphocytes constitute a multiclonal population of cells that express homologous heavy chain variable region genes, each rearranged to one of several distinct and apparently nonmutated D and JH gene segments. Collectively, these studies indicate that expression of nondiversified autoantibody-encoding variable region genes may not be an exclusive property of B cells that bear detectable levels of the CD5 surface antigen.

Kipps, T J; Duffy, S F

1991-01-01

97

Multiple large and small cerebellar infarcts  

PubMed Central

To assess the clinical, topographical, and aetiological features of multiple cerebellar infarcts,18 patients (16.5% of patients with cerebellar infarction) were collected from a prospective acute stroke registry, using a standard investigation protocol including MRI and magnetic resonance angiography. Infarcts in the posterior inferior cerebellar artery (PICA)+superior cerebellar artery (SCA) territory were most common (9/18; 50%), followed by PICA+anterior inferior cerebellar artery (AICA)+SCA territory infarcts (6/18; 33%). One patient had bilateral AICA infarcts. No infarct involved the PICA+AICA combined territory. Other infarcts in the posterior circulation were present in half of the patients and the clinical presentation largely depended on them. Large artery disease was the main aetiology. Our findings emphasised the common occurrence of very small multiple cerebellar infarcts (<2 cm diameter).These very small multiple cerebellar infarcts may occur with (13 patients/18; 72%) or without (3/18; 22%) territorial cerebellar infarcts. Unlike previous series, they could not all be considered junctional infarcts (between two main cerebellar artery territories: 51/91), but also small territorial infarcts (40/91). It is suggested that these very small territorial infarcts may be endzone infarcts, due to the involvement of small distal arterial branches. It is possible that some very small territorial infarcts may be due to a microembolic process, but this hypothesis needs pathological confirmation.??

Canaple, S.; Bogousslavsky, J.

1999-01-01

98

Mars Descent Imager (MARDI) on the Mars Polar Lander  

NASA Astrophysics Data System (ADS)

The Mars Descent Imager, or MARDI, experiment on the Mars Polar Lander (MPL) consists of a camera characterized by small physical size and mass (~6 × 6 × 12 cm, including baffle; <500 gm), low power requirements (<2.5 W, including power supply losses), and high science performance (1000 × 1000 pixel, low noise). The intent of the investigation is to acquire nested images over a range of resolutions, from 8 m/pixel to better than 1 cm/pixel, during the roughly 2 min it takes the MPL to descend from 8 km to the surface under parachute and rocket-powered deceleration. Observational goals will include studies of (1) surface morphology (e.g., nature and distribution of landforms indicating past and present environmental processes) (2) local and regional geography (e.g., context for other lander instruments: precise location, detailed local relief) and (3) relationships to features seen in orbiter data. To accomplish these goals, MARDI will collect three types of images. Four small images (256 × 256 pixels) will be acquired on 0.5 s centers beginning 0.3 s before MPL's heatshield is jettisoned. Sixteen full-frame images (1024 × 1024, circularly edited) will be acquired on 5.3 s centers thereafter. Just after backshell jettison but prior to the start of powered descent, a ``best final nonpowered descent image'' will be acquired. Five seconds after the start of powered descent, the camera will begin acquiring images on 4 s centers. Storage for as many as ten 800 × 800 pixel images is available during terminal descent. A number of spacecraft factors are likely to impact the quality of MARDI images, including substantial motion blur resulting from large rates of attitude variation during parachute descent and substantial rocket-engine-induced vibration during powered descent. In addition, the mounting location of the camera places the exhaust plume of the hydrazine engines prominently in the field of view.

Malin, M. C.; Caplinger, M. A.; Carr, M. H.; Squyres, S.; Thomas, P.; Veverka, J.

2001-08-01

99

Pasteurellaceae isolated from tonsillar samples of commercially-reared American bison (Bison bison).  

PubMed Central

As commercial producers of American bison (Bison bison) become more numerous, concerns relative to bison health management increase. Since loss due to respiratory disease associated with Pasteurella and related Pasteurellaceae is a major concern for cattle producers, a study was conducted to determine what types of Pasteurellaceae are carried by bison to evaluate the potential of pneumonic pasteurellosis in bison herds where management practices are comparable to those used for cattle. Tonsillar biopsies, collected in May (n = 29) and August (n = 25) 1997 from 24- to 30-month-old bison bulls, at the time of slaughter were cultured for Pasteurellaceae. Pasteurella spp. were isolated from all the samples collected in May. These included isolates identified as P. haemolytica, trehalosi, testudinis, and multocida subsp. multocida a and multocida b. Actinobacillus spp. and Haemophilus somnus were also isolated from some samples. Pasteurella spp., haemolytica, trehalosi, and multocida subsp. multocida a, multocida b and septica, plus 2 nonspeciated indole-positive biotypes, U2 and U16, were isolated from the second group of tonsil samples. Most of these organisms, including P. haemolytica, P. multocida subsp., and H. somnus are associated with disease in domestic livestock and should be regarded as potential pathogens for bison, particularly in animals which become stressed by management practices commonly used with cattle such as herding, crowding, and shipping. Images Figure 1.

Ward, A C; Dyer, N W; Fenwick, B W

1999-01-01

100

Carcinoma of the tonsillar region - results of external irradiation. [/sup 60/Co; 2MV photons  

SciTech Connect

A retrospective analysis is made of 104 patients treated with photon megavoltage radiotherapy for squamous cell carcinoma of the tonsillar region during the period 1965-1976. Moderately differentiated squamous cell carcinoma was the most common histological grade. Fifty-three per cent of the cases presented with cervical lymphadenopathy with three cases of bilateral involvement. The three year local control rate was 100% for Stage I, 74% Stage II, 49% Stage III, and 33% Stage IV. Two Stage III cases and one Stage IV case developed subsequent contralateral neck disease. No patient with either T/sub 1/N/sub 0/ or T/sub 2/N/sub 0/ tumor failed in the ipsilateral or contralateral neck despite the fact that 42% of the T/sub 1/N/sub 0/ cases and 37% of the T/sub 2/N/sub 0/ cases were treated with unilateral portals. The prognostic significance of the T and N stages, treatment techniques, as well as dose response relationships are analyzed and the literature is reviewed.

Tong, D. (Univ. of Washington, Seattle); Laramore, G.E.; Griffin, T.W.; Russel, A.H.; Tesh, D.W.; Taylor, W.J.; Martenson, J.A.

1982-05-15

101

Corticosteroids suppress in vitro tonsillar proliferation in children with obstructive sleep apnoea.  

PubMed

Intranasal corticosteroids (CS) are potentially useful interventions for children with obstructive sleep apnoea (OSA), and may reduce lymphadenoid tissue size in the upper airway. The present authors hypothesised that CS would reduce cellular proliferation and the production of pro-inflammatory cytokines in a tonsil/adenoid mixed-cell culture system. Dissociated tonsils or adenoids harvested intra-operatively from children with polysomnographically diagnosed OSA were cultured in control medium (CO) or after stimulation with lipopolysaccharide and concanavalin A (STIM), and incubated with dexamethasone (DEX; 10(-5)-10(-7) M), fluticasone (FLU; 10(-5)-10(-14) M) and budesonide (BUD; 10(-4)-10(-14) M). Proliferation and apoptosis were assessed, and supernatants were assayed for the cytokines tumour necrosis factor (TNF)-alpha, interleukin (IL)-6 and IL-8. STIM increased tonsillar and adenoidal proliferation compared with CO (1,976+/-133 versus 404+/-69 counts min(-1); n = 54). DEX, FLU and BUD reduced cellular proliferation rates, and exhibited dose-dependent effects, with the potency being FLU>BUD>DEX (n = 25 per group). Conversely, CS increased cellular apoptosis (n = 20 per group). Furthermore, TNF-alpha, IL-8 and IL-6 concentrations in the supernatant were increased by STIM, and markedly reduced by all CS (n = 48 per group). Whole tissue cell cultures of adenoids and tonsils provide a useful approach for in vitro assessment of therapeutic efficacy of corticosteroids in the management of lymphadenoid hypertrophy that underlies obstructive sleep apnoea in children. PMID:19047310

Kheirandish-Gozal, L; Serpero, L D; Dayyat, E; Kim, J; Goldman, J L; Snow, A; Bhattacharjee, R; Gozal, D

2008-12-01

102

Autonomic involvement in extrapyramidal and cerebellar disorders  

Microsoft Academic Search

We reviewed the clinical and autonomic features of all patients with extrapyramidal and cerebellar disorders studied in the Mayo Autonomic Reflex Laboratory from 1983 to 1989. Patients were grouped into the following categories (number in parentheses): Parkinson's disease (35); parkinsonism-plus (54); multiple system atrophy (75); hereditary multisystem degenerations (eleven); progressive supranuclear palsy (32); non-familial cerebellar degeneration (eleven); nonspecific sporadic multisystem

Paola Sandroni; J. Eric Ahlskog; Robert D. Fealey; Phillip A. Low

1991-01-01

103

Cellular and molecular basis of cerebellar development.  

PubMed

Historically, the molecular and cellular mechanisms of cerebellar development were investigated through structural descriptions and studying spontaneous mutations in animal models and humans. Advances in experimental embryology, genetic engineering, and neuroimaging techniques render today the possibility to approach the analysis of molecular mechanisms underlying histogenesis and morphogenesis of the cerebellum by experimental designs. Several genes and molecules were identified to be involved in the cerebellar plate regionalization, specification, and differentiation of cerebellar neurons, as well as the establishment of cellular migratory routes and the subsequent neuronal connectivity. Indeed, pattern formation of the cerebellum requires the adequate orchestration of both key morphogenetic signals, arising from distinct brain regions, and local expression of specific transcription factors. Thus, the present review wants to revisit and discuss these morphogenetic and molecular mechanisms taking place during cerebellar development in order to understand causal processes regulating cerebellar cytoarchitecture, its highly topographically ordered circuitry and its role in brain function. PMID:23805080

Martinez, Salvador; Andreu, Abraham; Mecklenburg, Nora; Echevarria, Diego

2013-06-26

104

Cerebellar zones: a personal history.  

PubMed

Cerebellar zones were there, of course, before anyone noticed them. Their history is that of young people, unhindered by preconceived ideas, who followed up their observations with available or new techniques. In the 1960s of the last century, the circumstances were fortunate because three groups, in Leiden, Lund, and Bristol, using different approaches, stumbled on the same zonal pattern in the cerebellum of the cat. In Leiden, the Häggqvist myelin stain divulged the compartments in the cerebellar white matter that channel the afferent and efferent connections of the zones. In Lund, the spino-olivocerebellar pathways activated from individual spinal funiculi revealed the zonal pattern. In Bristol, charting the axon reflex of olivocerebellar climbing fibers on the surface of the cerebellum resulted in a very similar zonal map. The history of the zones is one of accidents and purposeful pursuit. The technicians, librarians, animal caretakers, students, secretaries, and medical illustrators who made it possible remain unnamed, but their contributions certainly should be acknowledged. PMID:20967577

Voogd, Jan

2011-09-01

105

Genetic disorders and cerebellar structural abnormalities in childhood  

Microsoft Academic Search

Summary Amongst 78 patients with either unilateral or bilateral (ponto-) cerebellar hypoplasia, atrophy or lesions on neuro- imaging (CT and\\/or MRI), 16 showed unilateral hypoplasia or lesions, 15 vermis defects, nine pontocerebellar hypoplasia, 10 non-progressive conditions with bilateral cerebellar hemisphere hypoplasia or lesions and 28 progressive cerebellar atrophy. Known genetic conditions did not occur with unilateral cerebellar involvement, whereas a

V. Ramaekers; J. Reul; A. Thron; J. Jaeken

1997-01-01

106

Topography of cerebellar deficits in humans.  

PubMed

The cerebellum is a key-piece for information processing and is involved in numerous motor and nonmotor activities, thanks to the anatomical characteristics of the circuitry, the enormous computational capabilities and the high connectivity to other brain areas. Despite its uniform cytoarchitecture, cerebellar circuitry is segregated into functional zones. This functional parcellation is driven by the connectivity and the anatomo-functional heterogeneity of the numerous extra-cerebellar structures linked to the cerebellum, principally brain cortices, precerebellar nuclei and spinal cord. Major insights into cerebellar functions have been gained with a detailed analysis of the cerebellar outputs, with the evidence that fundamental aspects of cerebrocerebellar operations are the closed-loop circuit and the predictions of future states. Cerebellar diseases result in disturbances of accuracy of movements and lack of coordination. The cerebellar syndrome includes combinations of oculomotor disturbances, dysarthria and other speech deficits, ataxia of limbs, ataxia of stance and gait, as well as often more subtle cognitive/behavioral impairments. Our understanding of the corresponding anatomo-functional maps for the human cerebellum is continuously improving. We summarize the topography of the clinical deficits observed in cerebellar patients and the growing evidence of a regional subdivision into motor, sensory, sensorimotor, cognitive and affective domains. The recently described topographic dichotomy motor versus nonmotor cerebellum based upon anatomical, functional and neuropsychological studies is also discussed. PMID:21240580

Grimaldi, Giuliana; Manto, Mario

2012-06-01

107

X-linked disorders with cerebellar dysgenesis  

PubMed Central

X-linked disorders with cerebellar dysgenesis (XLCD) are a genetically heterogeneous and clinically variable group of disorders in which the hallmark is a cerebellar defect (hypoplasia, atrophy or dysplasia) visible on brain imaging, caused by gene mutations or genomic imbalances on the X-chromosome. The neurological features of XLCD include hypotonia, developmental delay, intellectual disability, ataxia and/or other cerebellar signs. Normal cognitive development has also been reported. Cerebellar dysgenesis may be isolated or associated with other brain malformations or multiorgan involvement. There are at least 15 genes on the X-chromosome that have been constantly or occasionally associated with a pathological cerebellar phenotype. 8 XLCD loci have been mapped and several families with X-linked inheritance have been reported. Recently, two recurrent duplication syndromes in Xq28 have been associated with cerebellar hypoplasia. Given the report of several forms of XLCD and the excess of males with ataxia, this group of conditions is probably underestimated and families of patients with neuroradiological and clinical evidence of a cerebellar disorder should be counseled for high risk of X-linked inheritance.

2011-01-01

108

Cerebellar Motor Function in Spina Bifida Meningomyelocele  

PubMed Central

Spina bifida meningomyelocele (SBM), a congenital neurodevelopmental disorder, involves dysmorphology of the cerebellum, and its most obvious manifestations are motor deficits. This paper reviews cerebellar neuropathology and motor function across several motor systems well studied in SBM in relation to current models of cerebellar motor and timing function. Children and adults with SBM have widespread motor deficits in trunk, upper limbs, eyes, and speech articulators that are broadly congruent with those observed in adults with cerebellar lesions. The structure and function of the cerebellum are correlated with a range of motor functions. While motor learning is generally preserved in SBM, those motor functions requiring predictive signals and precise calibration of the temporal features of movement are impaired, resulting in deficits in smooth movement coordination as well as in the classical cerebellar triad of dysmetria, ataxia, and dysarthria. That motor function in individuals with SBM is disordered in a manner phenotypically similar to that in adult cerebellar lesions, and appears to involve similar deficits in predictive cerebellar motor control, suggests that age-based cerebellar motor plasticity is limited in individuals with this neurodevelopmental disorder.

Dennis, Maureen; Salman, Michael S.; Juranek, Jenifer; Fletcher, Jack M.

2010-01-01

109

TWIST1 promoter methylation is associated with prognosis in tonsillar squamous cell carcinoma.  

PubMed

Tonsillar squamous cell carcinomas (TSCC) frequently present with locally advanced diseases and cervical metastases, which are associated with poor prognoses. Epithelial-mesenchymal transition (EMT) is critical for tumor invasiveness and metastatic potential. Recent studies have shown that TWIST1-inducing EMT is overexpressed and hypermethylated in several cancers, indicating disease progression. The aim of the present study was to determine the clinical and prognostic significance of TWIST1 hypermethylation and EMT-related protein expression in TSCC. Methylation levels of TWIST1 promoter were analyzed by quantitative real-time methylation-specific polymerase chain reaction. Immunohistochemical analyses of TWIST1, Snail, and SMAD nuclear interacting protein-1 (SNIP1) were performed in 65 formalin-fixed, paraffin-embedded blocks of surgically resected specimens. TWIST1 promoter hypermethylation was found in 27.7% (18/65) of TSCCs. TWIST1 promoter hypermethylation was associated with poor differentiation (P = .012). Contralateral cervical lymph node metastasis was more frequently observed in TWIST1-methylated tumors (P = .029). High protein expressions of TWIST1, Snail, and SNIP1 were observed in 14 TSCC specimens (21.5%), 21 TSCC specimens (32.3%), and 38 TSCC specimens (58.5%), respectively. SNIP1 expression correlated significantly with TWIST1 methylation (P = .001), whereas TWIST1 protein expression did not. Contralateral cervical lymph node metastasis was an independent risk factor of the decreased overall survival rate (P = .002). TWIST1 methylation (P = .031) and pN stage (P = .037) were independent factors of poor prognoses affecting disease-free survival. TWIST1 promoter hypermethylation may be a useful molecular marker for predicting prognoses and contralateral cervical lymph node metastases in patients with TSCC. PMID:23664538

Kwon, Mi Jung; Kwon, Ji Hyun; Nam, Eun Sook; Shin, Hyung Sik; Lee, Dong Jin; Kim, Jin Hwan; Rho, Young Soo; Sung, Chang Ohk; Lee, Won Jae; Cho, Seong Jin

2013-05-10

110

Visual disturbance associated with postoperative cerebellar mutism.  

PubMed

Cerebellar mutism is an uncommon complication of posterior fossa surgery. Manifestations include disturbances of articulation, prosody, and pitch, and, if severe, complete mutism. Symptoms are independent of recognizable cortical or brainstem injury, and recovery is variable, with permanent deficits frequently observed. Cerebellar dysfunction is commonly invoked as an etiology, although controversy remains concerning the mechanism. Visual impairment has been reported only once before in the setting of this disorder. We report a confirmatory case of sudden, severe visual loss in association with cerebellar mutism after resection of a midline medulloblastoma in a 7-year-old. PMID:15664775

Daniels, Stacie R; Moores, Leon E; DiFazio, Marc P

2005-02-01

111

Women of African Descent: Persistence in Completing Doctorates  

ERIC Educational Resources Information Center

|This study examines the educational persistence of women of African descent (WOAD) in pursuit of a doctorate degree at universities in the southeastern United States. WOAD are women of African ancestry born outside the African continent. These women are heirs to an inner dogged determination and spirit to survive despite all odds (Pulliam, 2003,…

Iddrisu, Vannetta Bailey

2010-01-01

112

Correlations, Descent Measures: Drift with Migration and Mutation  

Microsoft Academic Search

The analysis of gene frequencies for a nested structure of genes within individuals, individuals within subpopulations, and subpopulations within populations is considered. Alternative parameterizations are provided by measures of correlation and of identity by descent, but the latter parameters provide more flexibility. The effects of population size, mating system, mutation, and migration can be incorporated into transition equations for identity

C. Clark Cockerham; B. S. Weir

1987-01-01

113

Mars Descent Imager (MARDI) on the Mars Polar Lander  

Microsoft Academic Search

The Mars Descent Imager, or MARDI, experiment on the Mars Polar Lander (MPL) consists of a camera characterized by small physical size and mass (~6 × 6 × 12 cm, including baffle; <500 gm), low power requirements (<2.5 W, including power supply losses), and high science performance (1000 × 1000 pixel, low noise). The intent of the investigation is to

M. C. Malin; M. A. Caplinger; M. H. Carr; S. Squyres; P. Thomas; J. Veverka

2001-01-01

114

Direct Temperature Measurements during Netlander Descent on Mars  

Microsoft Academic Search

A new design for a platinum thermoresistance temperature sensor has been developed and tested in Earth's atmosphere and stratosphere. It will be one of the sensors equipping the scientific package ATMIS (Atmospheric and Meteorology Instrument System), which will be devoted to the measurement of the meteorological parameters during both the entry\\/descent phase and the surface phase, aboard the Netlanders. In

G. Colombatti; F. Angrilli; F. Ferri; A. Francesconi; M. Fulchignoni; P. F. Lion Stoppato; B. Saggi

1999-01-01

115

Pregnant Women of Mexican Descent: Constructions of Motherhood  

Microsoft Academic Search

Past research related to pregnancy outcomes has tended to have a bio-medical focus. More recent research has begun to explore possible social and cultural influences on birth outcomes. Qualitative interviews were conducted with 28 pregnant women of Mexican descent in the Texas\\/Mexico border region to begin to describe the social and cultural contexts of pregnancy of women of Mexican ancestry.

Faith W. Lucas

2010-01-01

116

Descents and nodal load in scale-free networks  

NASA Astrophysics Data System (ADS)

The load of a node in a network is the total traffic going through it when every node pair sustains a uniform bidirectional traffic between them on shortest paths. We express nodal load in terms of the more elementary notion of a node’s descents in breadth-first-search [(BFS) or shortest-path] trees and study both the descent and nodal-load distributions in the case of scale-free networks. Our treatment is both semianalytical (combining a generating-function formalism with simulation-derived BFS branching probabilities) and computational for the descent distribution; it is exclusively computational in the case of the load distribution. Our main result is that the load distribution, even though it can be disguised as a power law through subtle (but inappropriate) binning of the raw data, is in fact a succession of sharply delineated probability peaks, each of which can be clearly interpreted as a function of the underlying BFS descents. This find is in stark contrast with previously held belief, based on which a power law of exponent -2.2 was conjectured to be valid regardless of the exponent of the power-law distribution of node degrees.

Bareinboim, Elias; Barbosa, Valmir C.

2008-04-01

117

Overview of the Phoenix Entry, Descent and Landing System Architecture.  

National Technical Information Service (NTIS)

NASA s Phoenix Mars Lander began its journey to Mars from Cape Canaveral, Florida in August 2007, but its journey to the launch pad began many years earlier in 1997 as NASA s Mars Surveyor Program 2001 Lander. In the intervening years, the entry, descent ...

B. D. Cichy M. R. Grover P. N. Desai

2008-01-01

118

Prediction of identity by descent probabilities from marker-haplotypes  

Microsoft Academic Search

The prediction of identity by descent (IBD) probabilities is essential for all methods that map quantitative trait loci (QTL). The IBD probabilities may be predicted from marker genotypes and\\/or pedigree information. Here, a method is presented that predicts IBD probabilities at a given chromosomal location given data on a haplotype of markers spanning that position. The method is based on

Theo H. E. MEUWISSEN; Mike E. GODDARD

2001-01-01

119

STS40 descent BET products: Development and results  

Microsoft Academic Search

Descent Best Estimate Trajectory (BET) Data were generated for the final Orbiter Experiments Flight, STS-40. This report discusses the actual development of these post-flight products: the inertial BET, the Extended BET, and the Aerodynamic BET. Summary results are also included. The inertial BET was determined based on processing Tracking and Data Relay Satellite (TDRSS) coherent Doppler data in conjunction with

Kevin F. Oakes; James S. Wood; John T. Findlay

1991-01-01

120

Huygens probe entry and descent trajectory analysis and reconstruction techniques  

NASA Astrophysics Data System (ADS)

Cassini/Huygens is a joint National Aeronautics and Space Administration (NASA)/European Space Agency (ESA)/Agenzia Spaziale Italiana (ASI) mission on its way to explore the Saturnian system. The ESA Huygens Probe is scheduled to be released from the Orbiter on 25 December 2004 and enter the atmosphere of Titan on 14 January 2005. Probe delivery to Titan, arbitrarily defined to occur at a reference altitude of 1270 km above the surface of Titan, is the responsibility of the NASA Jet Propulsion Laboratory (JPL). ESA is then responsible for safely delivering the probe from the reference altitude to the surface. The task of reconstructing the probe trajectory and attitude from the entry point to the surface has been assigned to the Huygens Descent Trajectory Working Group (DTWG), a subgroup of the Huygens Science Working Team. The DTWG will use data provided by the Huygens Probe engineering subsystems and selected data sets acquired by the scientific payload. To correctly interpret and correlate results from the probe science experiments and to provide a reference set of data for possible "ground-truthing" Orbiter remote sensing measurements, it is essential that the trajectory reconstruction be performed as early as possible in the post-flight data analysis phase. The reconstruction of the Huygens entry and descent trajectory will be based primarily on the probe entry state vector provided by the Cassini Navigation Team, and measurements of acceleration, pressure, and temperature made by the Huygens Atmospheric Structure Instrument (HASI). Other data sets contributing to the entry and descent trajectory reconstruction include the mean molecular weight of the atmosphere measured by the probe Gas Chromatograph/Mass Spectrometer (GCMS) in the upper atmosphere and the Surface Science Package (SSP) speed of sound measurement in the lower atmosphere, accelerations measured by the Central and Radial Accelerometer Sensor Units (CASU/RASU), and the probe altitude by the two probe radar altimeters during the latter stages of the descent. In the last several hundred meters, the altitude determination will be constrained by measurements from the SSP acoustic sounder. Other instruments contributing data to the entry and descent trajectory and attitude determination include measurements of the zonal wind drift by the Doppler Wind Experiment (DWE), and probe zonal and meridional drift and probe attitude by the Descent Imager and Spectral Radiometer (DISR). In this paper, the need for and the methods by which the Huygens Probe entry and descent trajectory will be reconstructed are reviewed.

Atkinson, D. H.; Kazeminejad, B.; Gaborit, V.; Ferri, F.; Lebreton, J.-P.

2005-04-01

121

Moebius' syndrome with unilateral cerebellar hypoplasia  

Microsoft Academic Search

A case is reported of a child with Moebius' syndrome who also has unilateral cerebellar hypoplasia. We suggest that this combination of abnormalities could result from a vascular disruption occurring in the basilar artery early in its development.

M G Harbord; J P Finn; M A Hall-Craggs; E M Brett; M Baraitser

1989-01-01

122

Cerebellar mutism following posterior fossa tumour surgery.  

PubMed

Two cases of transient mutism following operative removal of cerebellar medulloblastoma are reported. These add to the few cases reported in the literature of this rare complication of posterior fossa tumour surgery in children. PMID:8861318

Jones, S; Kirollos, R W; Van Hille, P T

1996-04-01

123

Unusual cerebellar ganglioglioma with marked cytologic atypia.  

PubMed

Neuronal differentiation is well documented in cerebellar primitive neuroectodermal tumors but is uncommon in other cerebellar neoplasms. Although rare, gangliogliomas and gangliocytomas have been previously described in the cerebellum. We report a cerebellar ganglioglioma in a 14-year-old boy, which revealed bizzare markedly pleomorphic cells with extremely pronounced nuclear atypia but less than one mitosis per 50 high-power fields and no necrosis. The tumor showed glial as well as neuronal differentiation, with abundant bi- and multinucleated ganglion cells. There were abundant Rosenthal fibers, eosinophilic granular bodies, focal calcification, and perivascular lymphocytic infiltrates. There has been no evidence of tumor recurrence or neurological deterioration 21 years after surgery, although the marked nuclear atypia led to an initial diagnosis of an anaplastic glioma. We stress the need for careful evaluation of cerebellar gliomas in children that show only nuclear atypia or endothelial hyperplasia in the absence of other features of malignancy. PMID:9050064

Jay, V; Greenberg, M

124

Cerebellar Motor Function in Spina Bifida Meningomyelocele  

Microsoft Academic Search

Spina bifida meningomyelocele (SBM), a congenital neurodevelopmental disorder, involves dysmorphology of the cerebellum, and\\u000a its most obvious manifestations are motor deficits. This paper reviews cerebellar neuropathology and motor function across\\u000a several motor systems well studied in SBM in relation to current models of cerebellar motor and timing function. Children\\u000a and adults with SBM have widespread motor deficits in trunk, upper

Maureen Dennis; Michael S. Salman; Jenifer Juranek; Jack M. Fletcher

2010-01-01

125

High incidence of progressive postnatal cerebellar enlargement in Costello syndrome: brain overgrowth associated with HRAS mutations as the likely cause of structural brain and spinal cord abnormalities.  

PubMed

Costello syndrome is a rasopathy caused by germline mutations in the proto-oncogene HRAS. Its presentation includes failure-to-thrive with macrocephaly, characteristic facial features, hypertrophic cardiomyopathy, papillomata, malignant tumors, and cognitive impairment. In a systematic review we found absolute or relative macrocephaly (100%), ventriculomegaly (50%), and other abnormalities on brain and spinal cord imaging studies in 27/28 individuals. Posterior fossa crowding with cerebellar tonsillar herniation (CBTH) was noted in 27/28 (96%), and in 10/17 (59%) with serial studies posterior fossa crowding progressed. Sequelae of posterior fossa crowding and CBTH included hydrocephalus requiring shunt or ventriculostomy (25%), Chiari 1 malformation (32%), and syrinx formation (25%). Our data reveal macrocephaly with progressive frontal bossing and CBTH, documenting an ongoing process rather than a static congenital anomaly. Comparison of images obtained in young infants to subsequent studies demonstrated postnatal development of posterior fossa crowding. This process of evolving megalencephaly and cerebellar enlargement is in keeping with mouse model data, delineating abnormal genesis of neurons and glia, resulting in an increased number of astrocytes and enlarged brain volume. In Costello syndrome and macrocephaly-capillary malformation syndrome disproportionate brain growth is the main factor resulting in postnatal CBTH and Chiari 1 malformation. PMID:20425820

Gripp, Karen W; Hopkins, Elizabeth; Doyle, Daniel; Dobyns, William B

2010-05-01

126

Visually Guided Step Descent in Children with Williams Syndrome  

ERIC Educational Resources Information Center

Individuals with Williams syndrome (WS) have impairments in visuospatial tasks and in manual visuomotor control, consistent with parietal and cerebellar abnormalities. Here we examined whether individuals with WS also have difficulties in visually controlling whole-body movements. We investigated visual control of stepping down at a change of…

Cowie, Dorothy; Braddick, Oliver; Atkinson, Janette

2012-01-01

127

Detection of human papillomavirus DNA and oncoprotein overexpression are associated with distinct morphological patterns of tonsillar squamous cell carcinoma.  

PubMed Central

Human papillomavirus (HPV) DNA has been detected in approximately 15% of squamous cell carcinomas (SCCs) of the head and neck. Recent studies have shown a predilection of HPV for certain anatomical sites, especially the tonsillar region, with viral DNA identified in approximately 60% of SCCs of the Waldeyer's tonsillar ring. This study was undertaken to determine whether there are differences in morphology or in oncogene expression in SCC of the tonsil with and without detectable HPV DNA. Twenty-two SCCs of the tonsil were analyzed for the presence of HPV DNA by polymerase chain reaction (PCR) using both a consensus primer set (My09/My11) and type-specific primers. Viral transcription was established in both primary and metastatic tumors by RNA in situ hybridization. The morphology of invasive SCC was classified into three subtypes: well keratinized (K-SCC), intermediate keratinized (I-SCC), and poorly keratinized (P-SCC). Expression of p53, pRB, and cyclin D1 (bcl-1) were studied by immunohistochemistry. In these cases (6 K-SCCs, 2 I-SCCs, and 14 P-SCCs), HPV DNA was detected in 14 (64%), with 11 containing HPV-16 (10 P-SCCs, 1 I-SCCs, and 0 K-SCCs) and 1 each containing HPV-33, HPV-59, and an unclassified HPV type (all P-SCCs). Viral oncoprotein E6/E7 transcription was demonstrated in 7 of 7 HPV-16-positive tumors. Cyclin D1 protein overexpression was detected in the majority of HPV-negative tumors (7 of 8 cases), whereas it was minimal or absent in 13 HPV-positive tumors. Overexpression of p53 protein was detected in 3 HPV-negative K-SCCs. In the HPV-positive tumors, fewer malignant cells expressed pRB and the staining was less intense than in the HPV-negative cancers. HPV DNA and E6/E7 expression, especially HPV-16, is detected in the majority of tonsillar SCCs and is almost exclusively associated with a poorly keratinized tumor histology. Decreased expression of cyclin D1, pRB, and p53 in tumors with HPV DNA is consistent with the known effects of the viral oncoproteins on the cellular protein. The morphology of the HPV-positive tumors suggests that HPV may have a predilection for a population of nonkeratinizing squamous cells or that the virally transformed cells inhibit keratinization of the tumor cells. Well keratinized tonsillar SCCs lack HPV DNA and are associated with overexpression of cyclin D1 protein and/or p53, suggesting that mechanisms that alter the cell cycle regulatory proteins, either by interaction with viral oncoproteins or by changes in the cellular proteins themselves, is critical for tumorigenesis of tonsillar SCC. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8

Wilczynski, S. P.; Lin, B. T.; Xie, Y.; Paz, I. B.

1998-01-01

128

Penicillin V, loracarbef and clindamycin in tonsillar surface fluid during acute group A streptococcal pharyngotonsillitis.  

PubMed

Patients with acute group A- strepotococcal pharyngotonsillitis were randomly assigned to treatment for 10 d with either phenoxymethylpenicillin (PcV), loracarbef or clindamycin. The concentrations of the drugs, respectively, were determined in tonsillar surface fluid (TSF), serum and the saliva in each patient on altogether 5 occasions; before, during and 4 d after end of therapy. On the same occasions blood was drawn for analysis of C-reactive protein (CRP) and orosomucoid. On the last d of treatment PcV could be detected in TSF in 1 of 6 patients only. Loracarbef had a slower decrease in TSF during therapy and measurable levels did occur 2 d after end of therapy corresponding to MIC 100 for GAS. This may be related to the somewhat better clinical results of the cephalosporins than of PcV, and possibly indicates that an extended therapy with these drugs in primary GAS pharyngotonsillitis for more than the arbitrarily chosen 10 d could reduce the number of recurrent episodes. PcV and loracarbef were not detected in serum after the end of treatment. The concentration of clindamycin in both TSF and the saliva was fairly longstanding during therapy and reached levels exceeding MIC 100 for GAS, in both TSF and serum 2 d after the end of treatment. Several investigations have shown that GAS, especially in the stationary phase may invade respiratory epithelial cells and are present intracellularly in patients with acute pharyngotonsillitis as well as in asymptomatic carriers. The same T-type, identical DNA fingerprints and arbitrarily primed patterns are found in GAS before and after treatment failure indicating that the primary episode and the failures are caused by the same strain. The longstanding concentrations of clindamycin in TSF, roughly independent of the degree of the local inflammation combined with its intracellular accumulation and activity against resting GAS seem to explain the efficiency of the drug in recurrent GAS pharyngotonsillitis. CRP and orosomucoid were of limited value in differing between bacterial and viral pharyngtonsillitis and a correlation between antibiotic concentration and CRP/orosomucoid levels was not found. PMID:16012002

Orrling, Arne; Kamme, Carl; Stjernquist-Desatnik, Anna

2005-01-01

129

[Some consideration about cerebellar ataxia and crossed cerebellar diaschisis in Dejerine-Roussy syndrome].  

PubMed

We report a 68-year-old right-handed male who exhibited Dejerine-Roussy syndrome including a persistent cerebellar ataxia following the left thalamic hemorrhage with special reference to the evolution of crossed cerebellar diaschisis (CCD) measured with positron emission tomography (PET). The initial PET studies performed 50 days after onset revealed a mild reduction of blood flow and glucose metabolism in the right cerebellar hemisphere in addition to the severe reduction in the left thalamus. Even in the chronic stage when the motor weakness almost disappeared, he persistently showed a cerebellar ataxia in his right extremities. The cerebellar blood flow and metabolism became normalized without laterality in the follow-up PET studies which were performed 29 months after onset, although the left thalamus and left cerebral cortices were still severely involved. The cerebellar ataxia with preserved cerebellar blood flow and metabolism following the thalamic hemorrhage was possibly associated with damage to the efferent fibers from the cerebellum, whereas the CCD observed in the early stage probably was caused by a transient involvement of the cortico-ponto-cerebellar tract at the level of the internal capsule. PMID:8200148

Ogawa, M; Nagata, K; Satoh, Y; Hirata, Y; Hatazawa, J

1994-03-01

130

Open wedge high tibial osteotomy: cause of patellar descent.  

PubMed

This was a retrospective review of the nine open wedge high tibial osteotomy (HTO) done in a regional hospital in Hong Kong from 2006 to 2008. The mechanical hip-knee-ankle angle improved from average 169.5°(164°-175°) to average 183.9° (179°-187°). Patellar descent was noted in all patients postoperatively, with Blackburne-Peel (BP) index significantly changing from 0.78 (0.64-0.93) to 0.59 (0.38-0.78) (p < 0.05). This change was strongly correlated with the size of anterior bone graft (r = -0.766; p = 0.016). The patellar tendon length as measured by Insall-Salvati index was not changed (pre-operative: 1.02 (0.88-1.25), final: 1.09 (0.8-1.22) (p = 0.683)), inferring that scarring contracture of patellar tendon was not related to patellar descent. PMID:22240018

Fan, Jason C H

2012-01-12

131

Open wedge high tibial osteotomy: cause of patellar descent  

PubMed Central

This was a retrospective review of the nine open wedge high tibial osteotomy (HTO) done in a regional hospital in Hong Kong from 2006 to 2008. The mechanical hip-knee-ankle angle improved from average 169.5°(164°-175°) to average 183.9° (179°-187°). Patellar descent was noted in all patients postoperatively, with Blackburne-Peel (BP) index significantly changing from 0.78 (0.64-0.93) to 0.59 (0.38-0.78) (p < 0.05). This change was strongly correlated with the size of anterior bone graft (r = -0.766; p = 0.016). The patellar tendon length as measured by Insall-Salvati index was not changed (pre-operative: 1.02 (0.88-1.25), final: 1.09 (0.8-1.22) (p = 0.683)), inferring that scarring contracture of patellar tendon was not related to patellar descent.

2012-01-01

132

Implications on cerebellar function from information coding.  

PubMed

One function of the cerebellar cortex is to process information. There are at least two types of information. Temporal information is encoded in the timing pattern of action and synaptic potentials, whereas structural information is encoded in the spatial pattern of the cerebellar synaptic circuitry. Intuitively, analysis of highly complex information in the time domain would require a cerebellar cortex with structural complexity to match. Information theory offers a way to estimate quantitatively both types of information and thereby helps to test hypotheses or advance theories of cerebellar neurobiology. These estimates suggest: (i) That the mossy-fiber-granule-cell system carries far more (temporal) information than the climbing fiber system, (ii) that Purkinje cells extract only a fraction of the (temporal) information from their afferents, and (iii) that the cerebellar cortex has a large (spatial) information coding capacity. Concerning information, one can argue that the cerebellar cortex analyzes temporal information in its afferents as a search engine, in search of coincidental mossy fiber events based on timing cues provided by climbing fiber events. Results of successive searches are continuously being converted into structural information encoded in the spatial distribution pattern of granule-cell-Purkinje-cell synapses along granule cell axons, thereby providing an adaptive and indeed self-correcting dimension to the structural information code. The search engine operation involves cellular mechanisms acting on temporal events and is part of an associative learning process. The conversion and generation of structural information involves neuroplasticity mechanisms acting at the synaptic level, with electrophysiological as well as structural consequences, and may be part of the short- and long-term memory process. These and other attributes qualify the cerebellar cortex as a dynamic information processing center, contributing to memory and learning while linking motor output with sensory events. PMID:18418669

Huang, Chiming

2008-01-01

133

Mars Exploration Rovers Entry, Descent, and Landing Trajectory Analysis  

Microsoft Academic Search

th and 25 th of 2004, respectively. The trajectory analysis performed to define the entry, descent, and landing (EDL) scenario is described. The entry requirements and constraints are presented, as well as uncertainties used in a Monte Carlo dispersion analysis to statistically assess the robustness of the entry design to off-nominal conditions. In the analysis, six-degree-of-freedom and three-degree-of-freedom trajectory re-

Prasun N. Desai; Philip C. Knocke

2004-01-01

134

Scaling Up Coordinate Descent Algorithms for Large ?1 Regularization Problems  

SciTech Connect

We present a generic framework for parallel coordinate descent (CD) algorithms that has as special cases the original sequential algorithms of Cyclic CD and Stochastic CD, as well as the recent parallel Shotgun algorithm of Bradley et al. We introduce two novel parallel algorithms that are also special cases---Thread-Greedy CD and Coloring-Based CD---and give performance measurements for an OpenMP implementation of these.

Scherrer, Chad; Halappanavar, Mahantesh; Tewari, Ambuj; Haglin, David J.

2012-07-03

135

Dynamic MR colpocystorectography assessing pelvic-floor descent  

Microsoft Academic Search

.   Magnetic resonance colpocystorectography (MR-CCRG) is presented in the evaluation of patients with pelvic-floor disorders.\\u000a Five healthy volunteers and 44 female patients with isolated or combined visceral descent underwent dynamic MRI and dynamic\\u000a fluoroscopy (DF). MR-CCRG was performed with the patient in a supine position using a True FISP sequence (1 image\\/1.2 s; in-plane\\u000a resolution 1.02 mm) during pelvic floor

A. Lienemann; C. Anthuber; A. Baron; P. Kohz; M. Reiser

1997-01-01

136

Continuous Steepest Descent Path for Traversing Non-convex Regions  

Microsoft Academic Search

This paper revisits the ideas of seeking unconstrained minima by following a continuous steepest descent path (CSDP). We are especially interested in the merits of such an ap- proach in regions where the objective function is non-convex and Newton-like methods become ineffective. The paper combines ODE-trajectory following with trust-region ideas to give an algorithm which performs curvilinear searches on each

S. Beddiaf

2009-01-01

137

An approximate, maximum-terminal-velocity descent to a point  

Microsoft Academic Search

A neighboring extremal control problem is formulated for a hypersonic glider to execute a maximum-terminal-velocity descent to a stationary target in a vertical plane. The resulting two-part, feedback control scheme initially solves a nonlinear algebraic problem to generate a nominal trajectory to the target altitude. Secondly, quadrature about the nominal provides the lift perturbation necessary to achieve the target downrange.

G. Richard Eisler; David G. Hull

1988-01-01

138

Tonsillar application of killed Streptococcus mutans induces specific antibodies in rabbit saliva and blood plasma without inducing a cross-reacting antibody to human cardiac muscle.  

PubMed

When Streptococcus mutans cells are injected into the skeletal muscle of rabbits, an antibody against human cardiac muscle, as well as an anti-S. mutans antibody, is induced in blood plasma. Our previous study showed that when sheep erythrocytes are applied to palatine tonsils, an antibody against the applied cells is induced both in blood plasma and saliva. This antibody has no activity against cardiac muscle. It is not clear, however, if S. mutans application to the tonsils evokes an antibody response against cardiac muscle. In this study, we immunized rabbits against S. mutans or Streptococcus sobrinus by tonsillar application or by intramuscular injection every 3 days for 6 weeks. Tonsillar applications of formalin-killed cells of S. mutans induced saliva immunoglobulin A (IgA) and blood plasma IgG to the applied cells. In contrast, intramuscular injection of such cells induced only blood plasma IgG. When the route of immunization was intramuscular injection, antibodies in blood plasma cross-reacted with cardiac muscle. By enzyme-immunohistochemistry and Ouchterlony immunodiffusion tests, no cross-reaction to cardiac muscle was observed with the antibody in saliva or in blood plasma after the tonsillar applications. Western blotting of the S. mutans antigen showed that blood plasma from rabbits injected with S. mutans reacted with antigens of 46, 52, 62, and 85 kDa, while that from rabbits subjected to tonsillar application of S. mutans did not react with these bands. Similar results were obtained for S. sobrinus applications. Thus, tonsillar applications of mutants group streptococci induce antibodies differing in antigen specificity and do not induce any cross-reacting antibody to cardiac muscle. PMID:9353033

Fukuizumi, T; Inoue, H; Tsujisawa, T; Uchiyama, C

1997-11-01

139

Cholestanol induces apoptosis of cerebellar neuronal cells.  

PubMed

Cerebrotendinous xanthomatosis (CTX) is a hereditary lipid storage disease characterized by hyper-cholestanolemia, cerebellar ataxia, xanthoma, and cataract. We hypothesized that cholestanol in serum of CTX patients might induce neuronal cell death in the cerebellum and eventually lead to cerebellar ataxia. To gain support for this hypothesis we developed hyper-cholestanolemia rats by feeding cholestanol. Neuronal cells, especially Purkinje cells in the cerebellum were stained by Sudan black B only in the cholestanol-fed rats, indicating the deposit of cholestanol in cerebellum. To examine effects of cholestanol in vitro, cerebellar neuronal cells were cultured with cholestanol. The cholestanol concentration increased and the viability decreased in cells cultured with cholestanol. Apoptosis was evident in cells cultured with cholestanol more frequently than in control cells, determined using the terminal deoxynucleotidyl transferase (TdT) dUTP nick end-labeling (TUNEL) method. As activities of interleukin-1beta-converting enzyme (ICE) and CPP32 protease were increased in cells cultured with cholestanol, all these data taken together suggest that cholestanol induced apoptosis of cerebellar neuronal cells. Our observations may explain the mechanism of cerebellar ataxia of CTX patients. PMID:10066446

Inoue, K; Kubota, S; Seyama, Y

1999-03-01

140

Measurements of methane absorption by the descent imager\\/spectral radiometer (DISR) during its descent through Titan's atmosphere  

Microsoft Academic Search

New low-temperature methane absorption coefficients pertinent to the Titan environment are presented as derived from the Huygens DISR spectral measurements combined with the in-situ measurements of the methane gas abundance profile measured by the Huygens Gas Chromatograph\\/Mass Spectrometer (GCMS). The visible and near-infrared spectrometers of the descent imager\\/spectral radiometer (DISR) instrument on the Huygens probe looked upward and downward covering

M. G. Tomasko; B. Bézard; L. Doose; S. Engel; E. Karkoschka

2008-01-01

141

Transient cerebellar mutism after evacuation of a spontaneous vermian haematoma.  

PubMed

Cerebellar mutism after surgery for posterior fossa tumours in children is a well-described, though rare, entity. Most of these tumours are located in the region of the cerebellar vermis extending to the hemispheres. The authors report a case of cerebellar mutism in an 8-year-old boy who underwent surgical evacuation of a spontaneous vermian haematoma. We feel that his mutism was an extreme form of cerebellar dysarthria. PMID:9808255

Sinha, A K; Rajender, Y; Dinakar, I

1998-09-01

142

Infection of primary human tonsillar lymphoid cells by KSHV reveals frequent but abortive infection of T cells  

PubMed Central

The lymphotropic herpesvirus KSHV principally infects B cells in vivo and is linked to several human B cell lymphoproliferative syndromes. Here we examine the susceptibility of primary tonsillar lymphocytes to infection by a recombinant KSHV (rKSHV.219) that constitutively expresses GFP. At an MOI of ~ 1, ca 5–10% of CD19+ B cells became GFP-positive. Surprisingly, in the same culture many more T cells became infected. However, in contrast to isolated B cells, isolated infected T cells did not support correct viral transcription and did not produce infectious virus, indicating the presence of one or more post-entry blocks to lytic KSHV replication in T cells. No immortalization or transformation has yet been observed in either B or T cells. These results affirm the feasibility of studying KSHV infection in primary lymphoid cells, and help to rationalize the detection of KSHV DNA in rare human T cell lymphomas in vivo.

Myoung, Jinjong; Ganem, Don

2011-01-01

143

Lightning: an unusual cause of cerebellar infarction.  

PubMed

The neurological complications of lightning injury are not infrequent. However, scarce data are available on cerebellar infarction attributable to lightning injury. A 45 year old man was admitted to the emergency department because of lightning injury. The patient had a Glasgow coma scale score of 13/15 on arrival at hospital with accompanying dysarthria and hypotonia. Computed tomography of the head showed only a mild cerebral oedema. Ataxia was recorded on the fourth day. Magnetic resonance imaging of the head showed ischaemia predominantly in the cerebellar hemispheres bilaterally and in the parietal, temporal, and frontal lobes on the right. Anti-oedema treatment was started. The patient was discharged after seven days. After one month the patient was re-examined and found to have minimal ataxia and dysarthria. Lightning injury should not be overlooked in the aetiology and differential diagnosis of acute cerebellar ischaemic insult and relevant clinical findings in adults. PMID:15496717

Aslan, S; Yilmaz, S; Karcioglu, O

2004-11-01

144

Language and Social Communication in Children with Cerebellar Dysgenesis  

Microsoft Academic Search

Objective: Acquired cerebellar lesions in children and adults may determine deficits of executive functions, visuoperceptual skills, expressive language and modulation of affect; a complex pattern termed ‘cerebellar cognitive affective syndrome’. However, the long-term sequelae of malformative cerebellar lesions have yet to be systematically investigated, particularly in children. The purpose of this study was to present preliminary longitudinal data on the

Alessandro Tavano; Franco Fabbro; Renato Borgatti

2007-01-01

145

Ionic mechanisms of autorhythmic firing in rat cerebellar Golgi cells  

Microsoft Academic Search

Although Golgi cells (GoCs), the main type of inhibitory interneuron in the cerebellar granular layer (GL), are thought to play a central role in cerebellar network function, their excitable properties have remained unexplored. GoCs fire rhythmically in vivo and in slices, but it was unclear whether this activity originated from pacemaker ionic mechanisms. We explored this issue in acute cerebellar

Lia Forti; Elisabetta Cesana; Jonathan Mapelli; Egidio D'Angelo

2006-01-01

146

Pre-operative cerebellar mutism secondary to vagus nerve schwannoma.  

PubMed

Cerebellar mutism, also known as 'posterior fossa syndrome,' is an uncommon condition often reported after posterior fossa tumour resection in the paediatric population. It is infrequently associated with other intrinsic cerebellar pathologies. We hereby report a rare case of pre-operative cerebellar mutism associated with an extrinsic posterior fossa lesion - vagus nerve schwannoma. PMID:22111953

Muthappan, Muthupalaniappaan; Correia, Jason; Muthu, Thirayan; Hussain, Zakier

2011-11-23

147

Unilateral cerebellar hypoplasia with different clinical features.  

PubMed

Unilateral cerebellar hypoplasia (UCH) is a rare pathological condition characterized by the loss of volume in cerebellar hemispheres ranging from mild asymptomatic to severe symptomatic cases. As the designation of UCH remains problematic, the underlying etiopathogenesis also lacks explanation. We investigated the patients admitted to Departments of Child Neurology, Neurology, and Genetics between the years 1992 and 2010 and detected 12 patients with unilateral cerebellar volume loss, with the exclusion of all other cerebellar pathologies. The ages of patients ranged between 6 months to 55 years. Five patients had a delay in developmental milestones, and one of these was diagnosed with neurofibromatosis type 1. Two patients had epileptic seizures, one patient had peripheral facial paralysis as a component of Moebius syndrome, and four patients were incidentally diagnosed during etiological work-up for headache. The clinical outcomes of patients varied from healthy subjects to marked developmental impairment. Radiologically, five patients had severe disproportionate UCH, six had moderate disproportionate, and one had mild proportionate UCH. Cerebellar peduncles were affected in all, and vermis was partly hypoplastic in eight patients. Brainstem was involved in four patients, and seven patients showed involvement of white matter and/or corpus callosum. Imaging features supported that patients with severe disproportionate UCH also displayed additional cerebral and commissural changes, which were related to ischemic or vascular injuries, implying a prenatally acquired disruption. In the presence of such a wide spectrum of clinical and radiological features, a prenatally acquired lesion and, thus, a disruption seem to be more explanatory rather than a primary developmental process or malformation in the etiopathogenesis of unilateral cerebellar hypoplasia. PMID:20967575

Benbir, Gulcin; Kara, Simay; Yalcinkaya, Beyza Citci; Karhkaya, Geysu; Tuysuz, Beyhan; Kocer, Naci; Yalcinkaya, Cengiz

2011-03-01

148

Long-term effects of transient cerebellar mutism after cerebellar astrocytoma or medulloblastoma tumor resection in childhood  

Microsoft Academic Search

Background  Following cerebellar tumor resection, some patients develop transient cerebellar mutism (TCM). Although the mutism resolves, it is not known whether there are long-term motor speech deficits in patients with TCM that are in excess of those in individuals with cerebellar tumors who had not developed postoperative TCM.Methods  Long-term survivors of cerebellar tumors resected in childhood who developed TCM were matched to

Joelene F. Huber; Kim Bradley; Brenda J. Spiegler; Maureen Dennis

2006-01-01

149

Prognosis of cerebellar astrocytomas in children  

Microsoft Academic Search

Objective  Our main objective is to review a large series of cerebellar astrocytomas in children and evaluate the outcome of the patients\\u000a depending on astrocytoma class. The effect of astrocytoma characteristics on the children’s prognosis was determined by grouping\\u000a a series of cerebellar astrocytomas by their location, radiological aspect, size, and histology and determining whether this\\u000a was related with outcome.\\u000a \\u000a \\u000a \\u000a Materials

Francisco Villarejo; Jose Maria Belinchón de Diego; Álvaro Gómez de la Riva

2008-01-01

150

The Cerebellar Mutism Syndrome and Its Relation to Cerebellar Cognitive Function and the Cerebellar Cognitive Affective Disorder  

ERIC Educational Resources Information Center

|The postoperative cerebellar mutism syndrome (CMS), consisting of diminished speech output, hypotonia, ataxia, and emotional lability, occurs after surgery in up to 25% of patients with medulloblastoma and occasionally after removal of other posterior fossa tumors. Although the mutism is transient, speech rarely normalizes and the syndrome is…

Wells, Elizabeth M.; Walsh, Karin S.; Khademian, Zarir P.; Keating, Robert F.; Packer, Roger J.

2008-01-01

151

Factored form descent: a practical algorithm for coherence retrieval.  

PubMed

We formulate coherence retrieval, the process of recovering via intensity measurements the two-point correlation function of a partially coherent field, as a convex weighted least-squares problem and show that it can be solved with a novel iterated descent algorithm using a coherent-modes factorization of the mutual intensity. This algorithm is more memory-efficient than the standard interior point methods used to solve convex problems, and we verify its feasibility by reconstructing the mutual intensity of a Schell-model source from both simulated data and experimental measurements. PMID:23482147

Zhang, Zhengyun; Chen, Zhi; Rehman, Shakil; Barbastathis, George

2013-03-11

152

Gradient descent assimilation for the point-vortex model  

NASA Astrophysics Data System (ADS)

Data assimilation is concerned with incorporating (noisy) observations into (imperfect) models that describe the underlying dynamics of the system, in order to infer the properties of the current state, by ensuring that the assimilated trajectories are consistent with both the observations and model dynamics. For many physical systems, particularly in oceanography, observations are usually available in the form of Lagrangian (particle trajectory) data that are augmented into models describing the flow fields. The incorporation of Lagrangian data into models of flow presents several challenges concerning the potential complexity of the Lagrangian trajectories in relatively simple flow fields, for example the appearance of nonlinear effects that are triggered by the exponential rate of separation of tracer trajectories in the region of saddle points [1]. As such, standard linear-based data assimilation methods, such as the Kalman filter, can fail. A nonlinear approach known as gradient descent assimilation [2] is presented, in which analysis trajectories are found by minimising a cost function in an extended state space. The gradient descent approach is demonstrated in the context of assimilating Lagrangian tracer trajectories in two-dimensional flows of point-vortex systems. The point-vortex model plays an important role as a simplified version of many physical systems, including Bose-Einstein condensates, certain plasma configurations and inviscid turbulence, in which the model dynamics are described by a relatively simple system of nonlinear ODEs, which can exhibit regular or chaotic motion for the 2-point vortex or 3-point vortex system respectively. A set of tracer advection equations augment the point vortex model equations, allowing the observed tracer positions to update the state information about the unobserved vortex postions. The gradient descent approach to the two-point vortex system has been successfully demonstrated for the case of both full and partial observations in a wide variety of test cases. [1] K. Ide, L. Kuznetsov and C. K. R. T. Jones. Lagrangian data assimilation for point vortex systems, Journal of Turbulence, 3, 053 (2002). [2] K. Judd, L. A. Smith and A. Weisheimer. Gradient free descent: Shadowing and state estimation using limited derivative information, Physica D, 190, 153-166 (2004).

Suckling, E. B.; Smith, L. A.

2012-04-01

153

DISR imaging and the geometry of the descent of the Huygens probe within Titan's atmosphere  

Microsoft Academic Search

The Descent Imager\\/Spectral Radiometer (DISR) provided 376 images during the descent to Titan and 224 images after landing. Images of the surface had scales between 150m\\/pixel and 0.4mm\\/pixel, all of which we assembled into a mosaic. The analysis of the surface and haze features in these images and of other data gave tight constraints on the geometry of the descent,

Erich Karkoschka; Martin G. Tomasko; Lyn R. Doose; Chuck See; Elisabeth A. McFarlane; Stefan E. Schröder; Bashar Rizk

2007-01-01

154

Perinatal Cerebellar Injury in Human and Animal Models  

PubMed Central

Cerebellar injury is increasingly recognized through advanced neonatal brain imaging as a complication of premature birth. Survivors of preterm birth demonstrate a constellation of long-term neurodevelopmental deficits, many of which are potentially referable to cerebellar injury, including impaired motor functions such as fine motor incoordination, impaired motor sequencing and also cognitive, behavioral dysfunction among older patients. This paper reviews the morphogenesis and histogenesis of the human and rodent developing cerebellum, and its more frequent injuries in preterm. Most cerebellar lesions are cerebellar hemorrhage and infarction usually leading to cerebellar abnormalities and/or atrophy, but the exact pathogenesis of lesions of the cerebellum is unknown. The different mechanisms involved have been investigated with animal models and are primarily hypoxia, ischemia, infection, and inflammation Exposure to drugs and undernutrition can also induce cerebellar abnormalities. Different models are detailed to analyze these various disturbances of cerebellar development around birth.

Biran, Valerie; Verney, Catherine; Ferriero, Donna M.

2012-01-01

155

Cerebellar Contribution to Mental Rotation: a cTBS Study.  

PubMed

A cerebellar role in spatial information processing has been advanced even in the absence of physical manipulation, as occurring in mental rotation. The present study was aimed at investigating the specific involvement of left and right cerebellar hemispheres in two tasks of mental rotation. We used continuous theta burst stimulation to downregulate cerebellar hemisphere excitability in healthy adult subjects performing two mental rotation tasks: an Embodied Mental Rotation (EMR) task, entailing an egocentric strategy, and an Abstract Mental Rotation (AMR) task entailing an allocentric strategy. Following downregulation of left cerebellar hemisphere, reaction times were slower in comparison to sham stimulation in both EMR and AMR tasks. Conversely, identical reaction times were obtained in both tasks following right cerebellar hemisphere and sham stimulations. No effect of cerebellar stimulation side was found on response accuracy. The present findings document a specialization of the left cerebellar hemisphere in mental rotation regardless of the kind of stimulus to be rotated. PMID:23771602

Picazio, Silvia; Oliveri, Massimiliano; Koch, Giacomo; Caltagirone, Carlo; Petrosini, Laura

2013-12-01

156

Autosomal dominant cerebellar ataxia deafness and narcolepsy  

Microsoft Academic Search

A new autosomal dominant syndrome in a Swedish pedigree is described. Five patients were affected with cerebellar ataxia and sensorineural deafness. Four of these patients had symptoms of narcolepsy. Optic atrophy, other neurological abnormalities and psychiatric symptoms developed with increasing disease duration. Three patients had non-neurological disease in addition, including diabetes mellitus in two and hypertrophic cardiomyopathy in one. Autopsy

Atle Melberg; Jerker Hetta; Niklas Dahl; Inger Nennesmo; Mats Bengtsson; Rolf Wibom; Crawford Grant; Karl Henrik Gustavson; Per Olov Lundberg

1995-01-01

157

Lightning: an unusual cause of cerebellar infarction  

Microsoft Academic Search

The neurological complications of lightning injury are not infrequent. However, scarce data are available on cerebellar infarction attributable to lightning injury. A 45 year old man was admitted to the emergency department because of lightning injury. The patient had a Glasgow coma scale score of 13\\/15 on arrival at hospital with accompanying dysarthria and hypotonia. Computed tomography of the head

S Aslan; S Yilmaz; O Karcioglu

2004-01-01

158

Motor cortex excitability in acute cerebellar infarct.  

PubMed

Limited evidence to date has demonstrated changes in excitability that develops over the contralateral motor cortex after a cerebellar infarct. As such, the present study investigated changes in excitability over the contra- (contraM1) and ipsilateral motor cortices (ipsiM1), in patients with acute cerebellar infarct, to determine whether the changes may have functional relevance. Paired-pulse transcranial magnetic stimulation, combined with detailed clinical assessment, was undertaken in ten patients presenting with acute unilateral cerebellar infarct. Studies were undertaken within 1 week of ictus and followed longitudinally at 3-, 6-, and 12-month periods. Comparisons were made with 15 age-matched controls. Immediately following a stroke, short-interval intracortical inhibition (SICI) was significantly reduced over the contraM1 in all patients (P?=?0.01), while reduced over the ipsiM1 in those with severe functional impairment (P?=?0.01). Moreover, ipsiM1 SICI correlated with impairment (r?=?0.69, P?=?0.03), such that less SICI was observed in those patients with most impairment. Cortical excitability changes persisted over the follow-up period in the context of clinical improvement. Following an acute cerebellar infarct, excitability abnormalities develop over both motor cortices, more prominently in patients with severe functional impairment. The cortical changes, particularly over the ipsilateral motor cortex, may represent a functionally relevant plastic process that may guide future therapeutic strategies to better facilitate recovery. PMID:23728898

Huynh, William; Krishnan, Arun V; Vucic, Steve; Lin, Cindy S-Y; Kiernan, Matthew C

2013-12-01

159

Remote cerebellar hemorrhage after cervical spinal surgery.  

PubMed

Remote cerebellar hemorrhage (RCH) is an unpredictable and rare complication of spinal surgery. We report five cases of RCH following cervical spinal surgery, and summarize another seven similar cases from the literature. Dural opening with cerebrospinal fluid (CSF) hypovolemia seems to be an important factor contributing to RCH following cervical spinal surgery. As other authors have proposed, surgical positioning may be another factor contributing to RCH. RCH is thought to be hemorrhagic venous infarction, resulting from the stretching occlusion of the superior cerebellar vein by the cerebellar sag effect. Either intraoperative CSF loss or a postoperative CSF leak from drainage may cause cerebellar sag, further resulting in RCH. RCH is usually self-limiting, and most patients with RCH have an optimal outcome after conservative treatment. Severe cases that involved surgical intervention because of evidence of brainstem compression or hydrocephalus also had acceptable outcomes, compared to spontaneous CH. It has been suggested that one way to prevent RCH is to avoid extensive perioperative loss of CSF, by paying attention to surgical positioning during spinal surgery. We also underline the importance of early diagnosis and CSF expansion in the early treatment of RCH. PMID:23746536

Huang, Po-Hsien; Wu, Jau-Ching; Cheng, Henrich; Shih, Yang-Hsin; Huang, Wen-Cheng

2013-06-05

160

Vergence Deficits in Patients with Cerebellar Lesions  

ERIC Educational Resources Information Center

|The cerebellum is part of the cortico-ponto-cerebellar circuit for conjugate eye movements. Recent animal data suggest an additional role of the cerebellum for the control of binocular alignment and disconjugate, i.e. vergence eye movements. The latter is separated into two different components: fast vergence (to step targets) and slow vergence…

Sander, T.; Sprenger, A.; Neumann, G.; Machner, B.; Gottschalk, S.; Rambold, H.; Helmchen, C.

2009-01-01

161

TRPC channels promote cerebellar granule neuron survival  

Microsoft Academic Search

Channels formed by the transient receptor potential (TRP) family of proteins have a variety of physiological functions. Here we report that two members of the TRP cation channel (TRPC) subfamily, TRPC3 and 6, protected cerebellar granule neurons (CGNs) against serum deprivation–induced cell death in cultures and promoted CGN survival in rat brain. In CGN cultures, blocking TRPC channels or downregulating

Yichang Jia; Jian Zhou; Yilin Tai; Yizheng Wang

2007-01-01

162

Memory Consolidation in the Cerebellar Cortex  

PubMed Central

Several forms of learning, including classical conditioning of the eyeblink, depend upon the cerebellum. In examining mechanisms of eyeblink conditioning in rabbits, reversible inactivations of the control circuitry have begun to dissociate aspects of cerebellar cortical and nuclear function in memory consolidation. It was previously shown that post-training cerebellar cortical, but not nuclear, inactivations with the GABAA agonist muscimol prevented consolidation but these findings left open the question as to how final memory storage was partitioned across cortical and nuclear levels. Memory consolidation might be essentially cortical and directly disturbed by actions of the muscimol, or it might be nuclear, and sensitive to the raised excitability of the nuclear neurons following the loss of cortical inhibition. To resolve this question, we simultaneously inactivated cerebellar cortical lobule HVI and the anterior interpositus nucleus of rabbits during the post-training period, so protecting the nuclei from disinhibitory effects of cortical inactivation. Consolidation was impaired by these simultaneous inactivations. Because direct application of muscimol to the nuclei alone has no impact upon consolidation, we can conclude that post-training, consolidation processes and memory storage for eyeblink conditioning have critical cerebellar cortical components. The findings are consistent with a recent model that suggests the distribution of learning-related plasticity across cortical and nuclear levels is task-dependent. There can be transfer to nuclear or brainstem levels for control of high-frequency responses but learning with lower frequency response components, such as in eyeblink conditioning, remains mainly dependent upon cortical memory storage.

Kellett, Daniel O.; Fukunaga, Izumi; Chen-Kubota, Eva; Dean, Paul; Yeo, Christopher H.

2010-01-01

163

Active force perception depends on cerebellar function  

PubMed Central

Damage to the cerebellum causes characteristic movement abnormalities but is thought to have minimal impact on somatosensory perception. Traditional clinical assessments of patients with cerebellar lesions reveal no perceptual deficits despite the fact that the cerebellum receives substantial somatosensory information. Given that abnormalities have been reported in predicting the visual consequences of movement, we suspect that the cerebellum broadly participates in perception when motor output is required (i.e., active perception). Thus we hypothesize that cerebellar integrity is essential for somatosensory perception that requires motor activity, but not passive somatosensory perception. We compared the perceptual acuity of human cerebellar patients to that of healthy control subjects in several different somatosensory perception tasks with minimal visual information. We found that patients were worse at active force and stiffness discrimination but similar to control subjects with regard to passive cutaneous force detection, passive proprioceptive detection, and passive proprioceptive discrimination. Furthermore, the severity of movement symptoms as assessed by a clinical exam was positively correlated with impairment of active force perception. Notably, within the context of these perceptual tasks, control subjects and cerebellar patients displayed similar movement characteristics, and hence differing movement strategies are unlikely to underlie the differences in perception. Our results are consistent with the hypothesis that the cerebellum is vital to sensory prediction of self-generated movement and suggest a general role for the cerebellum in multiple forms of active perception.

Bhanpuri, Nasir H.; Okamura, Allison M.

2012-01-01

164

Radiation-induced cerebellar chondrosarcoma. Case report  

SciTech Connect

The authors report a case of chondrosarcoma arising in the cerebellum 16 years after treatment of a cerebellar malignant astrocytoma by subtotal resection and irradiation. It is thought that the chondrosarcoma arising within the intracranial cavity was a probable consequence of previous ionizing radiation.

Bernstein, M.; Perrin, R.G.; Platts, M.E.; Simpson, W.J.

1984-07-01

165

Vergence Deficits in Patients with Cerebellar Lesions  

ERIC Educational Resources Information Center

The cerebellum is part of the cortico-ponto-cerebellar circuit for conjugate eye movements. Recent animal data suggest an additional role of the cerebellum for the control of binocular alignment and disconjugate, i.e. vergence eye movements. The latter is separated into two different components: fast vergence (to step targets) and slow vergence…

Sander, T.; Sprenger, A.; Neumann, G.; Machner, B.; Gottschalk, S.; Rambold, H.; Helmchen, C.

2009-01-01

166

Cerebellar agenesis II: Motor and language functions  

Microsoft Academic Search

In a former study of a patient with cerebellar agenesis (HK) mild motor deficits, problems in delay eyeblink conditioning and mild to moderate deficits in IQ, planning behavior, visuospatial abilities, visual memory, and attention were found. The present study reports additional findings in the same patient. In the motor domain, impairments in fine motor manipulations, trace eyeblink conditioning and motor

S. Richter; A. Dimitrova; C. Hein-Kropp; H. Wilhelm; E. Gizewski; D. Timmann

2005-01-01

167

Cerebellar circuitry as a neuronal machine.  

PubMed

Shortly after John Eccles completed his studies of synaptic inhibition in the spinal cord, for which he was awarded the 1963 Nobel Prize in physiology/medicine, he opened another chapter of neuroscience with his work on the cerebellum. From 1963 to 1967, Eccles and his colleagues in Canberra successfully dissected the complex neuronal circuitry in the cerebellar cortex. In the 1967 monograph, "The Cerebellum as a Neuronal Machine", he, in collaboration with Masao Ito and Janos Szentágothai, presented blue-print-like wiring diagrams of the cerebellar neuronal circuitry. These stimulated worldwide discussions and experimentation on the potential operational mechanisms of the circuitry and spurred theoreticians to develop relevant network models of the machinelike function of the cerebellum. In following decades, the neuronal machine concept of the cerebellum was strengthened by additional knowledge of the modular organization of its structure and memory mechanism, the latter in the form of synaptic plasticity, in particular, long-term depression. Moreover, several types of motor control were established as model systems representing learning mechanisms of the cerebellum. More recently, both the quantitative preciseness of cerebellar analyses and overall knowledge about the cerebellum have advanced considerably at the cellular and molecular levels of analysis. Cerebellar circuitry now includes Lugaro cells and unipolar brush cells as additional unique elements. Other new revelations include the operation of the complex glomerulus structure, intricate signal transduction for synaptic plasticity, silent synapses, irregularity of spike discharges, temporal fidelity of synaptic activation, rhythm generators, a Golgi cell clock circuit, and sensory or motor representation by mossy fibers and climbing fibers. Furthermore, it has become evident that the cerebellum has cognitive functions, and probably also emotion, as well as better-known motor and autonomic functions. Further cerebellar research is required for full understanding of the cerebellum as a broad learning machine for neural control of these functions. PMID:16759785

Ito, Masao

168

High mammographic density in women of Ashkenazi Jewish descent.  

PubMed

INTRODUCTION: Percent mammographic density (PMD) adjusted for age and BMI is one of the strongest risk factors for breast cancer and is known to be approximately 60 percent heritable. Here we report a finding of an association between genetic ancestry and adjusted PMD. METHODS: We selected self-identified Caucasian women in the California Pacific Medical Center Research Institute Cohort whose screening mammograms placed them in the top or bottom quintiles of age- and body mass index-adjusted PMD. Our final data set included 474 women with the highest adjusted PMD and 469 with the lowest genotyped on the Illumina 1M platform. Principal component analysis (PCA) and identity-by-descent (IBD) analyses allowed us to infer the women's genetic ancestry and correlate it with adjusted PMD. RESULTS: Women of Ashkenazi Jewish ancestry, as defined by the first principal component (PC1) of PCA and identity-by-descent analyses, represented approximately 15 percent of the sample. Ashkenazi Jewish ancestry, defined by PC1, was associated with higher adjusted PMD (p = 0.004). Using multivariate regression to adjust for epidemiologic factors associated with PMD, including age at parity and use of postmenopausal hormone therapy, did not attenuate the association. CONCLUSION: Women of Ashkenazi Jewish ancestry based on genetic analysis are more likely to have high age- and BMI-adjusted PMD. Ashkenazi Jews may have a unique set of genetic variants or environmental risk factors that increase mammographic density. PMID:23668689

Caswell, Jennifer L; Kerlikowske, Karla; Shepherd, John A; Cummings, Steven R; Hu, Donglei; Huntsman, Scott; Ziv, Elad

2013-05-13

169

A Mixed Cell Culture Model for Assessment of Proliferation in Tonsillar Tissues from Children with Obstructive Sleep Apnea or Recurrent Tonsillitis  

PubMed Central

Background Recurrent infective tonsillitis (RI) and obstructive sleep apnea(OSA) are the major indications for adenotonsillectomy (T&A) in children. However, little is known on the determinants of lymphadenoid tissue proliferation in the pediatric upper airway. Aim To develop an in vitro culture system allowing for assessment of tonsillar or adenoidal proliferation under basal or stimulated conditions. Methods Tonsils surgically removed from pediatric patients with obstructive sleep apnea and recurrent tonsillitis during T&A, were dissociated using standard methods. Whole cell tonsillar cultures were either maintained in normal medium or stimulated with LPS (25 ?g /ml) and concanavalin A (10 ?g/ml) for 24 hours (STIM). Cellular proliferation was evaluated by [3H] thymidine incorporation. In parallel, supernatants were collected after 48 hours, and concentration of cytokines was measured using standard ELISA procedures. Results Basal proliferative rates were increased in the OSA group (305.2 ± 40.6 cpm; n=31) compared to RI group (232.8 ± 31.9 cpm; n=26; p <0.001). No significant differences in proliferative rates emerged after STIM between OSA and RI. Furthermore, basal TNF-alpha, IL-6, and IL-8 concentrations in the supernatant were increased in OSA-derived cultures compared to RI, but IL-8 was higher after STIM in RI, while IL-6 remained increased in OSA. Conclusions The proliferative rates and concentrations of inflammatory mediators in tonsillar cell cultures from children with OSA and RI suggest that lymphadenoid tissue proliferation in these 2 conditions may be regulated by different mechanisms. This novel method may allow for future development of specific therapeutic interventions aiming to curtail and reverse tonsillar and adenoidal hypertrophy in children in a disease-specific manner.

Serpero, Laura D.; Kheirandish-Gozal, Leila; Dayyat, Ehab; Goldman, Julie L.; Kim, Jinkwan; Gozal, David

2009-01-01

170

Awake intubation with Bonfil's retromolar fibroscope in a patient with hard and fixed swelling of the right side of the neck and the tonsillar tumor  

PubMed Central

Bonfil's rigid fibroscope is an instrument used to perform tracheal intubation, proven to be effective both in patients with normal and in those with difficult airways. We use this device in awake intubation in a patient presenting with a large right neck mass and a tonsillar tumor which limited the mouth opening. Also, we describe our technique of insertion of Bonfil's retromolar fibroscope from the right side of the mouth across the tongue.

Medhat, Mamdouh; Aljuhani, T.

2011-01-01

171

Nucleotide-binding and oligomerization domain-like receptors and retinoic acid inducible gene-like receptors in human tonsillar T lymphocytes.  

PubMed

Nucleotide-binding and oligomerization domain (NOD)-like receptors (NLRs) and retinoic acid-inducible gene (RIG)-like receptors (RLRs) are recently discovered cytosolic pattern-recognition receptors sensing mainly bacterial components and viral RNA, respectively. Their importance in various cells and disorders is becoming better understood, but their role in human tonsil-derived T lymphocytes remains to be elucidated. In this study, we evaluated expression and functional relevance of NLRs and RLRs in human tonsillar CD3(+) T lymphocytes. Immunohistochemistry, real-time RT-PCR and flow cytometry revealed expression of NOD1, NOD2, NALP1, NALP3, NAIP, IPAF, RIG-1, MDA-5 and LGP-2 at mRNA and protein levels. Because of the limited number of ligands (iE-DAP, MDP, Alum, Poly(I:C)/LyoVec), functional evaluation was restricted to NOD1, NOD2, NALP3 and RIG-1/MDA-5, respectively. Stimulation with the agonists alone was not enough to induce activation but upon triggering via CD3 and CD28, a profound induction of proliferation was seen in purified CD3(+) T cells. However, the proliferative response was not further enhanced by the cognate ligands. Nonetheless, in tonsillar mononuclear cells iE-DAP, MDP and Poly(I:C)/LyoVec were found to augment the CD3/CD28-induced proliferation of tonsillar mononuclear cells. Also, iE-DAP and MDP were found to promote secretion of interleukins 2 and 10 as well as to up-regulate CD69. This study demonstrates for the first time a broad range of NLRs and RLRs in human tonsillar T cells and that NOD1, NOD2 and RIG-1/MDA-5 act synergistically with ?CD3 and ?CD28 to induce proliferation of human T cells. Hence, these results suggest that these receptors have a role in T-cell activation. PMID:21342182

Petterson, Terese; Mĺnsson, Anne; Riesbeck, Kristian; Cardell, Lars O

2011-02-22

172

APOLLO 12 Mission Report Descent, Propulsion System Final Flight Evaluation (Supplement 5).  

National Technical Information Service (NTIS)

The results are presented of the postflight analysis of the Descent propulsion system (DPS) performance during the Apollo 12 Mission. The primary objective of the analysis was to determine the steady-state performance of the DPS during the descent phase o...

R. K. Seto R. L. Barrows

1972-01-01

173

The effect of the descent technique and truck cabin layout on the landing impact forces  

Microsoft Academic Search

The majority of injuries to truckers are caused by falls during the descent from the cab of the truck. Several studies have shown that the techniques used to descend from the truck and the layout of the truck's cabin are the principal cause of injury. The goal of the present study was to measure the effects of the descent techniques

Stéphane Patenaude; Denis Marchand; Sabina Samperi; Marc Bélanger

2001-01-01

174

Parsing Expression Grammar as a Primitive Recursive-Descent Parser with Backtracking  

Microsoft Academic Search

Two recent developments in the fleld of formal languages are Parsing Expression Grammar (PEG) and packrat parsing. The PEG formalism is similar to BNF, but deflnes syntax in terms of recognizing strings, rather than constructing them. It is, in fact, precise speciflcation of a backtracking recursive- descent parser. Packrat parsing is a general method to handle backtracking in recursive-descent parsers.

Roman R. Redziejowski

2007-01-01

175

From Psychology of Race to Issue of Skin Color: Western Trivialization and Peoples of African Descent  

Microsoft Academic Search

In the aftermath of Western colonization is the trivialization of skin color as significant issue in the psychology of peoples of African descent. Although social scientists use race as a key factor in elucidating and understanding human social conditions, skin color and its impact on the social and psychological disposition of people of African descent have been understudied. Oblivious to

Ronald E. Hall

2005-01-01

176

Effects of the Phoenix Lander descent thruster plume on the Martian surface  

Microsoft Academic Search

The exhaust plume of Phoenix's hydrazine monopropellant pulsed descent thrusters will impact the surface of Mars during its descent and landing phase in the northern polar region. Experimental and computational studies have been performed to characterize the chemical compounds in the thruster exhausts. No undecomposed hydrazine is observed above the instrument detection limit of 0.2%. Forty-five percent ammonia is measured

D. H. Plemmons; M. Mehta; B. C. Clark; S. P. Kounaves; L. L. Peach Jr; N. O. Renno; L. Tamppari; S. M. M. Young

2008-01-01

177

A dynamic continuous descent approach methodology for low noise and emission  

Microsoft Academic Search

Continuous Descent Approaches (CDAs) can significantly reduce fuel burn and noise impact by keeping arriving aircraft at their cruise altitude for longer than during conventional approaches(to descend as late as possible)and then having them make a continuous descent to the runway at near idle thrust with no level flight segments. The CDA procedures are fixed routes that are vertically optimized.

S. Alam; M. H. Nguyen; H. A. Abbass; C. Lokan; M. Ellejmi; S. Kirby

2010-01-01

178

Mitral annular descent velocity by tissue Doppler echocardiography as an index of global left ventricular function  

Microsoft Academic Search

Mitral annular descent has been described as an index of left ventricular (LV) systolic function, which is independent of endocardial definition. Echocardiographic tissue Doppler imaging is a new technique that calculates and displays color-coded cardiac tissue velocities on-line. To evaluate mitral annular descent velocity as a rapid index of global LV function, we performed tissue Doppler imaging studies in 55

Vijay K. Gulati; William E. Katz; William P. Follansbee; John Gorcsan

1996-01-01

179

Introduction to the special issue on lesbians of African descent: contemporary perspectives.  

PubMed

This article serves as an introduction to the special issue entitled, "Lesbians of African Descent: Contemporary Perspectives." We briefly discuss our framing of this collection as a contemporary contribution to the canon of Black lesbian writing and art, and identify themes that appear to transcend both earlier and current works of lesbians of African descent. PMID:21279896

Wilson, Bianca D M; Johnson, Verlena L

2011-01-01

180

Adaptive wavefront control with asynchronous stochastic parallel gradient descent clusters.  

PubMed

A scalable adaptive optics (AO) control system architecture composed of asynchronous control clusters based on the stochastic parallel gradient descent (SPGD) optimization technique is discussed. It is shown that subdivision of the control channels into asynchronous SPGD clusters improves the AO system performance by better utilizing individual and/or group characteristics of adaptive system components. Results of numerical simulations are presented for two different adaptive receiver systems based on asynchronous SPGD clusters-one with a single deformable mirror with Zernike response functions and a second with tip-tilt and segmented wavefront correctors. We also discuss adaptive wavefront control based on asynchronous parallel optimization of several local performance metrics-a control architecture referred to as distributed adaptive optics (DAO). Analysis of the DAO system architecture demonstrated the potential for significant increase of the adaptation process convergence rate that occurs due to partial decoupling of the system control clusters optimizing individual performance metrics. PMID:16985545

Vorontsov, Mikhail A; Carhart, Gary W

2006-10-01

181

Adaptive wavefront control with asynchronous stochastic parallel gradient descent clusters  

NASA Astrophysics Data System (ADS)

A scalable adaptive optics (AO) control system architecture composed of asynchronous control clusters based on the stochastic parallel gradient descent (SPGD) optimization technique is discussed. It is shown that subdivision of the control channels into asynchronous SPGD clusters improves the AO system performance by better utilizing individual and/or group characteristics of adaptive system components. Results of numerical simulations are presented for two different adaptive receiver systems based on asynchronous SPGD clusters—one with a single deformable mirror with Zernike response functions and a second with tip-tilt and segmented wavefront correctors. We also discuss adaptive wavefront control based on asynchronous parallel optimization of several local performance metrics—a control architecture referred to as distributed adaptive optics (DAO). Analysis of the DAO system architecture demonstrated the potential for significant increase of the adaptation process convergence rate that occurs due to partial decoupling of the system control clusters optimizing individual performance metrics.

Vorontsov, Mikhail A.; Carhart, Gary W.

2006-10-01

182

Isolated rhomboencephalosynapsis - a rare cerebellar anomaly  

PubMed Central

Summary Background: Rhomboencephalosynapsis (RES, RS) is a unique entity usually recognized in infancy based on neuroimaging. Cerebellar fusion and absence of cerebellar vermis is often associated with supratentorial findings. Since now there are about 50 cases described worldwide, with approximately 36 patients diagnosed by MRI. The authors present the first in Poland case of this uncommon malformation and review the literature. Case Report: The authors describe a 28-month-old-girl with microcephaly and proper psychomotor development. The family history was unrelevant. Based on MRI the congenital malformation of posterior fossa-rhombencephalosynapsis was confirmed Conclusions: Presented patient is a typical example of MRI usefulness especially in patients with RES. RES symptoms are mild and that is why the diagnosis is usually made only in adulthood.

Paprocka, Justyna; Jamroz, Ewa; Scieszka, Ewa; Kluczewska, Ewa

2012-01-01

183

An update on Spino-cerebellar ataxias  

PubMed Central

The dominantly inherited ataxias, also known as Spino-cerebellar ataxias (SCAs), are rapidly expanding entities. New mutations are being identified at remarkable regularity. Recent awareness of molecular abnormalities in SCAs has addressed some of the long sought questions, but gaps in knowledge still exist. Three major categories of SCAs, according to molecular mechanisms, have evolved over recent few years: Polyglutamate expansion ataxia, non-coding zone repeat ataxia, and ataxia due to conventional mutation. Using the fulcrum of these mechanisms, the article provides an update of SCAs. Shared and specific clinical features, genetic abnormalities, and possible links between molecular abnormalities and cerebellar degeneration have been discussed. Emphasis has been placed on the mechanisms of polyglutamate toxicity.

Mondal, Banashree; Paul, Pritikanta; Paul, Madhuparna; Kumar, Hrishikesh

2013-01-01

184

Cerebellar mutism after posterior cranial fossa surgery.  

PubMed

Mutism is a rare sequel of PCF tumor removal. Three patients aged 5 to 20 years old with mutism after posterior fossa surgery are presented. Suboccipital craniectomy was performed in all patients with grossly total removal of a medulloblastoma. The mutism that may occur after an operation for a PCF lesion has been explained in functional and/or organic terms. To date, 24 similar cases of mutism following cerebellar operations have been reported in the literature. We review the features of the syndrome in the light of the published cases and speculate on the underlying physiopathology. The absence of long tract or other brain stem signs, together with a presence of dysarthria during the recovery of speech, suggested a organic cerebellar cause of the mutism. PMID:8913962

Salvati, M; Cervoni, L; Santoro, A

1996-03-01

185

Cerebellar Pathway Changes Following Cerebral Hemispherectomy.  

PubMed

Following unilateral cerebral injury, several patterns of cerebellar metabolism have been noted on positron emission tomography (PET); these changes have been attributed both to the distant diaschisis as well as to reorganizational changes within the cerebellum. We used diffusion tensor magnetic resonance imaging (MRI) to study 14 children who had undergone cerebral hemispherectomy because of intractable epilepsy and compared them with those from 17 controls. In 10 children who had preoperative and postoperative scans, a paired comparison was performed. Our findings showed significantly higher fractional anisotropy values in corticopontocerebellar pathways postoperatively compared to preoperatively. When compared to controls, we found a higher rate of age-related fractional anisotropy changes of corticopontocerebellar pathways in the postoperative scans. Our results indicate reorganizational changes in the contralateral (intact) corticopontocerebellar pathway and the cerebellar white matter. These changes likely contribute to the far better motor outcomes seen in children compared to adults sustaining such cortical injuries. PMID:22965564

Govindan, Rajkumar Munian; Brescoll, Jennifer; Chugani, Harry T

2012-09-10

186

Y Chromosome Lineages in Men of West African Descent  

PubMed Central

The early African experience in the Americas is marked by the transatlantic slave trade from ?1619 to 1850 and the rise of the plantation system. The origins of enslaved Africans were largely dependent on European preferences as well as the availability of potential laborers within Africa. Rice production was a key industry of many colonial South Carolina low country plantations. Accordingly, rice plantations owners within South Carolina often requested enslaved Africans from the so-called “Grain Coast” of western Africa (Senegal to Sierra Leone). Studies on the African origins of the enslaved within other regions of the Americas have been limited. To address the issue of origins of people of African descent within the Americas and understand more about the genetic heterogeneity present within Africa and the African Diaspora, we typed Y chromosome specific markers in 1,319 men consisting of 508 west and central Africans (from 12 populations), 188 Caribbeans (from 2 islands), 532 African Americans (AAs from Washington, DC and Columbia, SC), and 91 European Americans. Principal component and admixture analyses provide support for significant Grain Coast ancestry among African American men in South Carolina. AA men from DC and the Caribbean showed a closer affinity to populations from the Bight of Biafra. Furthermore, 30–40% of the paternal lineages in African descent populations in the Americas are of European ancestry. Diverse west African ancestries and sex-biased gene flow from EAs has contributed greatly to the genetic heterogeneity of African populations throughout the Americas and has significant implications for gene mapping efforts in these populations.

Keita, Shomarka O. Y.; Kittles, Rick A.

2012-01-01

187

Y chromosome lineages in men of west African descent.  

PubMed

The early African experience in the Americas is marked by the transatlantic slave trade from ?1619 to 1850 and the rise of the plantation system. The origins of enslaved Africans were largely dependent on European preferences as well as the availability of potential laborers within Africa. Rice production was a key industry of many colonial South Carolina low country plantations. Accordingly, rice plantations owners within South Carolina often requested enslaved Africans from the so-called "Grain Coast" of western Africa (Senegal to Sierra Leone). Studies on the African origins of the enslaved within other regions of the Americas have been limited. To address the issue of origins of people of African descent within the Americas and understand more about the genetic heterogeneity present within Africa and the African Diaspora, we typed Y chromosome specific markers in 1,319 men consisting of 508 west and central Africans (from 12 populations), 188 Caribbeans (from 2 islands), 532 African Americans (AAs from Washington, DC and Columbia, SC), and 91 European Americans. Principal component and admixture analyses provide support for significant Grain Coast ancestry among African American men in South Carolina. AA men from DC and the Caribbean showed a closer affinity to populations from the Bight of Biafra. Furthermore, 30-40% of the paternal lineages in African descent populations in the Americas are of European ancestry. Diverse west African ancestries and sex-biased gene flow from EAs has contributed greatly to the genetic heterogeneity of African populations throughout the Americas and has significant implications for gene mapping efforts in these populations. PMID:22295064

Torres, Jada Benn; Doura, Menahem B; Keita, Shomarka O Y; Kittles, Rick A

2012-01-25

188

Assessment on EXPERT Descent and Landing System Aerodynamics  

NASA Astrophysics Data System (ADS)

EXPERT is a re-entry vehicle designed for validation of aero-thermodynamic models, numerical schemes in Computational Fluid Dynamics codes and test facilities for measuring flight data under an Earth re-entry environment. This paper addresses the design for the descent and landing sequence for EXPERT. It includes the descent sequence, the choice of drogue and main parachutes, and the parachute deployment condition, which can be supersonic or subsonic. The analysis is based mainly on an engineering tool, PASDA, together with some hand calculations for parachute sizing and design. The tool consists of a detailed 6-DoF simulation performed with the aerodynamics database of the vehicle, an empirical wakes model and the International Standard Atmosphere database. The aerodynamics database for the vehicle is generated by DNW experimental data and CFD codes within the framework of an ESA contract to CIRA. The analysis will be presented in terms of altitude, velocity, accelerations, angle-of- attack, pitch angle and angle of rigging line. Discussion on the advantages and disadvantages of each parachute deployment condition is included in addition to some comparison with the available data based on a Monte-Carlo method from a Russian company, FSUE NIIPS. Sensitivity on wind speed to the performance of EXPERT is shown to be strong. Supersonic deployment of drogue shows a better performance in stability at the expense of a larger G-load than those from the subsonic deployment of drogue. Further optimization on the parachute design is necessary in order to fulfill all the EXPERT specifications.

Wong, H.; Muylaert, J.; Northey, D.; Riley, D.

2009-01-01

189

Cerebellar mutism after posterior fossa surgery--two case reports.  

PubMed

Two adults (aged 71 and 74 years) developed cerebellar mutism after posterior fossa surgery for a mass lesion in the superior cerebellar hemisphere or upper vermis. Histological examination showed one was a hemangioblastoma, the other a metastatic brain tumor. The tumors were totally removed via the occipital transtentorial approach. Both patients developed mutism on the 2nd postoperative day, which persisted for 3-4 weeks and was followed within 2-4 months by cerebellar dysarthria. Thereafter, their condition improved. Transient cerebellar mutism usually occurs in pediatric patients after the removal of a mass lesion in the upper vermis. Cerebellar mutism in adults is rare. The predominance of cerebellar mutism in children may be attributable to the predilection for vermian tumor and their tendency to experience personality and behavioral changes after posterior fossa surgery. PMID:9465594

Kai, Y; Kuratsu, J; Suginohara, K; Marubayashi, T; Ushio, Y

1997-12-01

190

Spontaneous cerebellar haemorrhage following lumbar fusion  

Microsoft Academic Search

Spontaneous cerebellar haemorrhage following spinal surgery is rare, with fewer than 20 patients reported in the literature. We present a 70-year-old woman who underwent a L5–S1 posterior lumbar interbody fusion for spondylolisthesis. Intraoperatively, an incidental durotomy occurred and was repaired uneventfully. A large amount of serosanguinous fluid was noted in the subfascial drain post-operatively. The patient became increasingly drowsy 36

Peter Khong; M. Jerry Day

2009-01-01

191

14 CFR 121.333 - Supplemental oxygen for emergency descent and for first aid; turbine engine powered airplanes...  

Code of Federal Regulations, 2013 CFR

...for emergency descent and for first aid; turbine engine powered airplanes with pressurized...for emergency descent and for first aid; turbine engine powered airplanes with pressurized... (a) General. When operating a turbine engine powered airplane with a...

2013-01-01

192

Primary cerebellar haemorrhage: complications, treatment and outcome.  

PubMed

Given its anatomical proximity to the brainstem and the ventricular system, cerebellar haemorrhage may lead to immediate life-threatening complications such as brainstem compression and hydrocephalus, or to herniation through the foramen magnum or the tentorium. This situation mandates fast diagnosis and precise emergency treatment strategies. However, the treatment protocols in current use are based on little evidence and the indication criteria for surgical intervention are unclear. Early suboccipital decompressive surgery may be life-saving, but the potential risk involved is unnecessary if the haemorrhage is benign and can be managed conservatively or with insertion of an external ventricular drain. Deterioration of the patients' state of consciousness has often been used as an indication for surgery, but clinical decline can be a fulminant process leading to death within a short time. Research on cerebellar haemorrhage so far has focused on identifying outcome predictors from which treatment algorithms can be derived. Large randomised controlled trials (RCTs) are lacking. However, RCTs are urgently needed, in order to improve the level of evidence, treatment decisions may be based on. Here, we review the available literature on complications, treatment and outcome of primary cerebellar haemorrhage (PCH). Finally we propose the design of a potential RCT. PMID:23659765

Witsch, Jens; Neugebauer, Hermann; Zweckberger, Klaus; Jüttler, Eric

2013-05-06

193

Reactive tonsillar enlargement showing strong 18F-FDG uptake during the follow-up of follicular lymphoma.  

PubMed

The 18F-fluorodeoxyglucose positron emission tomography/computed tomography (FDG-PET/CT) has become a standard procedure for the diagnosis, staging, and restaging in lymphoma patients. However, a relative high rate of false-positive results has been reported. We report a case of a 40-year-old man with a previous history of a nodal follicular lymphoma, stage IVA, treated with R-CHOP, which showed strong 18F-FDG uptake in the Waldeyer's tonsillar ring during his follow-up, being considered highly suspicious of relapsed lymphoma. A surgical removal of the palatine tonsils and adenoids was performed, which showed reactive follicular hyperplasia. Furthermore, bone marrow biopsy revealed absence of neoplasia. The patient is still in follow-up with no signs of recurrent lymphoma. This case illustrates that, despite the high sensitivity for the detection of recurrent lymphoma, 18F-FDG uptake should be interpreted with great caution and confirmatory studies should be performed before any therapy. PMID:23011892

Feio, Patricia do Socorro Queiroz; Gomes, Camilla Borges Ferreira; Nogueira, Alexandre Simőes; Almeida, Luciana Yamamoto; Vassallo, José; Soares, Fernando Augusto; Almeida, Oslei Paes; León, Jorge Esquiche

2012-09-26

194

Identification of RNA aptamers that internalize into HPV-16 E6/E7 transformed tonsillar epithelial cells.  

PubMed

Human papillomavirus type 16 (HPV-16) associated oropharyngeal cancers are on a significant increase and better therapeutic strategies are needed. The HPV-16 oncogenes E6 and E7 are expressed in HPV-associated cancers and are able to transform human tonsillar epithelial cells (HTECs). We used cell-Systematic Evolution of Ligands by Exponential Enrichment (SELEX) to select for RNA aptamers that entered into HPV-16 E6/E7-HTECs. After 12 rounds of cell-SELEX, a pool of aptamers was obtained that had significantly greater internalization capacity (~5-fold) into E6/E7-HTECs as compared to primary HTECs or fibroblasts. Analysis of individual aptamers from the pool indicated variable internalization into E6/E7-HTECs (1-8-fold as compared to a negative control). Most of the individual aptamers internalized into E6/E7 and primary HTECs with similar efficiency, while one aptamer exhibited ~3-fold better internalization into E6/E7-HTECs. Aptamers that internalize into cells may be useful for delivering therapeutic agents to HPV-16 associated malignancies. PMID:24074596

Gourronc, Francoise A; Rockey, William M; Thiel, William H; Giangrande, Paloma H; Klingelhutz, Aloysius J

2013-09-08

195

Microglial activation underlies cerebellar deficits produced by repeated cannabis exposure.  

PubMed

Chronic cannabis exposure can lead to cerebellar dysfunction in humans, but the neurobiological mechanisms involved remain incompletely understood. Here, we found that in mice, subchronic administration of the psychoactive component of cannabis, delta9-tetrahydrocannabinol (THC), activated cerebellar microglia and increased the expression of neuroinflammatory markers, including IL-1?. This neuroinflammatory phenotype correlated with deficits in cerebellar conditioned learning and fine motor coordination. The neuroinflammatory phenotype was readily detectable in the cerebellum of mice with global loss of the CB1 cannabinoid receptor (CB1R, Cb1(-/-) mice) and in mice lacking CB1R in the cerebellar parallel fibers, suggesting that CB1R downregulation in the cerebellar molecular layer plays a key role in THC-induced cerebellar deficits. Expression of CB2 cannabinoid receptor (CB2R) and Il1b mRNA was increased under neuroinflammatory conditions in activated CD11b-positive microglial cells. Furthermore, administration of the immunosuppressant minocycline or an inhibitor of IL-1? receptor signaling prevented the deficits in cerebellar function in Cb1(-/-) and THC-withdrawn mice. Our results suggest that cerebellar microglial activation plays a crucial role in the cerebellar deficits induced by repeated cannabis exposure. PMID:23934130

Cutando, Laura; Busquets-Garcia, Arnau; Puighermanal, Emma; Gomis-González, Maria; Delgado-García, José María; Gruart, Agnčs; Maldonado, Rafael; Ozaita, Andrés

2013-06-24

196

Effects of cerebellar stimulation on processing semantic associations.  

PubMed

Current research in cerebellar cognitive and linguistic functions makes plausible the idea that the cerebellum is involved in processing temporally contiguous linguistic input. In order to assess this hypothesis, a lexical decision task was constructed to study the effects of cerebellar transcranial magnetic stimulation on semantic noun-to-verb priming based on association (e.g. 'soap-cleaning') or similarity (e.g. 'robbery-stealing'). The results demonstrated a selective increase in associative priming size after stimulation of a lateral cerebellar site. The findings are discussed in the contexts of a cerebellar role in linguistic expectancy generation and the corticocerebellar 'prefrontal' reciprocal loop. PMID:22752996

Argyropoulos, Giorgos P; Muggleton, Neil G

2013-02-01

197

Epilepsy and neuropsychologic deficit in a child with cerebellar astrocytoma.  

PubMed

We report the case of a 32-month-old female patient presenting with cerebellar pilocytic astrocytoma with epileptic seizures, psychomotor delay, and severe language delay. Usually, the typical onset of cerebellar tumor is characterized by raised intracranial pressure and cerebellar incoordination. A review of the few cases reported in the literature evidencing epileptic seizures symptomatic of a focal, nondegenerative mass limited to the cerebellum is included. Moreover, a discussion about the cerebellar contribution to nonmotor functions in children is presented, in particular following tumor resection. PMID:16970895

Strazzer, Sandra; Zucca, Claudio; Fiocchi, Isabella; Genitori, Lorenzo; Castelli, Enrico

2006-09-01

198

The Descent of Christ in Ephesians 4:9: Its Impact Upon the Use of the Apostles' Creed  

Microsoft Academic Search

Confusion runs rampant when it comes to certain theological issues such as the descent of Christ in Ephesians 4:9. Over the centuries, three main interpretations have arisen to explain this enigmatic text. The possible interpretations are that the descent was the Descensus ad Infernos during which Christ visited hell during the three days that He was dead, that the descent

Matthew C Hinson

2007-01-01

199

Validation of Genome-Wide Prostate Cancer Associations in Men of African Descent  

PubMed Central

Background Genome-wide association studies (GWAS) have identified numerous prostate cancer susceptibility alleles, but these loci have been identified primarily in men of European descent. There is limited information about the role of these loci in men of African descent. Methods We identified 7,788 prostate cancer cases and controls with genotype data for 47 GWAS-identified loci. Results We identified significant associations for SNP rs10486567 at JAZF1, rs10993994 at MSMB, rs12418451 and rs7931342 at 11q13, and rs5945572 and rs5945619 at NUDT10/11. These associations were in the same direction and of similar magnitude as those reported in men of European descent. Significance was attained at all report prostate cancer susceptibility regions at chromosome 8q24, including associations reaching genome-wide significance in region 2. Conclusion We have validated in men of African descent the associations at some, but not all, prostate cancer susceptibility loci originally identified in European descent populations. This may be due to heterogeneity in genetic etiology or in the pattern of genetic variation across populations. Impact The genetic etiology of prostate cancer in men of African descent differs from that of men of European descent.

Chang, Bao-Li; Spangler, Elaine; Gallagher, Stephen; Haiman, Christopher A.; Henderson, Brian; Isaacs, William; Benford, Marnita L.; Kidd, LaCreis R.; Cooney, Kathleen; Strom, Sara; Ann Ingles, Sue; Stern, Mariana C.; Corral, Roman; Joshi, Amit D.; Xu, Jianfeng; Giri, Veda N.; Rybicki, Benjamin; Neslund-Dudas, Christine; Kibel, Adam S.; Thompson, Ian M.; Leach, Robin J.; Ostrander, Elaine A.; Stanford, Janet L.; Witte, John; Casey, Graham; Eeles, Rosalind; Hsing, Ann W.; Chanock, Stephen; Hu, Jennifer J.; John, Esther M.; Park, Jong; Stefflova, Klara; Zeigler-Johnson, Charnita; Rebbeck, Timothy R.

2010-01-01

200

Hair trace elements in cerebellar degeneration: low copper levels in late cortical cerebellar atrophy  

Microsoft Academic Search

The levels of ten elements in the hair of 7 patients with olivopontocerebellar atrophy (OPCA), 10 patients with late cortical cerebellar atrophy (LCCA) and 1489 healthy persons were determined by inductively coupled plasma emission spectrometry. The phosphorus, zinc, selenium, calcium, magnesium, iron, managanese, aluminium and mercury concentrations did not show any statistically significant difference among the three groups. The copper

M. Oishi; T. Takasu; M. Tateno; H. Uchida

1990-01-01

201

Description of the computations and pilot procedures for planning fuel-conservative descents with a small programmable calculator  

SciTech Connect

A simplified flight management descent algorithm was developed and programmed on a small programmable calculator. It was designed to aid the pilot in planning and executing a fuel conservative descent to arrive at a metering fix at a time designated by the air traffic control system. The algorithm may also be used for planning fuel conservative descents when time is not a consideration. The descent path was calculated for a constant Mach/airspeed schedule from linear approximations of airplane performance with considerations given for gross weight, wind, and nonstandard temperature effects. The flight management descent algorithm and the vertical performance modeling required for the DC-10 airplane is described.

Vicroy, D.D.; Knox, C.E.

1983-05-01

202

Multiple branching of cerebellar efferent projections in cats  

Microsoft Academic Search

The retrograde labeling of neurons in the deep cerebellar nuclei with horseradish peroxidase was used to compare the morphological characteristics of neurons in the dentate and interposed nuclei projecting in the cerebellothalamic, cerebello-olivary, and cerebellar nucleocortical pathways. The results from these studies demonstrated that cerebellothalamic and nucleocortical projections from the dentate and interposed nuclei originate from similar populations of spindle-

D. L. Tolbert; H. Bantli; J. R. Bloedel

1978-01-01

203

Clinical features of developmental disability associated with cerebellar hypoplasia  

Microsoft Academic Search

Sporadic nonsyndromic cerebellar hypoplasia is a radiological diagnosis with clinical features and a relation with developmental disability that are presently not known. Through a retrospective review of a comprehensive standardized computerized database containing more than 2,500 patients examined consecutively by a pediatric neurologist, 11 with nonfamilial, nonsyndromic cerebellar hypoplasia on neuroimaging (CT and\\/or MRI) were identified. With the exception of

Michael I. Shevell; Annette Majnemer

1996-01-01

204

Functional effects of methylazoxymethanol-induced cerebellar hypoplasia in rats  

Microsoft Academic Search

The behavioral effects of a series of methylazoxymethanol acetate (MAM) injections in neonatal rats were investigated. Pups were injected twice daily on days 5–8 after birth with 4 mg\\/kg MAM or saline. Similar treatment paradigms cause cerebellar hypoplasia. which is a result of a depletion of granule cells. MAM treatment reduced adult cerebellar weight to 92% that of control and

Sherry A. Ferguson; Merle G. Paule; R. Robert Holson

1996-01-01

205

Nicotinic receptor abnormalities in the cerebellar cortex in autism  

Microsoft Academic Search

Summary Autism is a common developmental disorder associated with structural and inferred neurochemical abnormal- ities of the brain. Cerebellar abnormalities frequently have been identified, based on neuroimaging or neuro- pathology. Recently, the cholinergic neurotransmitter system has been implicated on the basis of nicotinic receptor loss in the cerebral cortex. Cerebellar choliner- gic activities were therefore investigated in autopsy tissue from

M. Lee; C. Martin-Ruiz; A. Graham; J. Court; E. Jaros; R. Perry; P. Iversen; M. Bauman; E. Perry

2002-01-01

206

Neocortical networks entrain neuronal circuits in cerebellar cortex  

PubMed Central

Activity in neocortex is often characterized by synchronized oscillations of neurons and networks, resulting in the generation of a local field potential and electroencephalogram. Do the neuronal networks of the cerebellum also generate synchronized oscillations and are they under the influence of those in the neocortex? Here we show that in the absence of any overt external stimulus, the cerebellar cortex generates a slow oscillation that is correlated with that of the neocortex. Disruption of the neocortical slow oscillation abolishes the cerebellar slow oscillation, whereas blocking cerebellar activity has no overt effect on the neocortex. We provide evidence that the cerebellar slow oscillation results in part from the activation of granule, Golgi, and Purkinje neurons. In particular, we show that granule and Golgi cells discharge trains of single spikes, and Purkinje cells generate complex spikes, during the Up state of the slow oscillation. Purkinje cell simple spiking is weakly related to the cerebellar and neocortical slow oscillation in a minority of cells. Our results indicate that the cerebellum generates rhythmic network activity that can be recorded as an LFP in the anesthetized animal, which is driven by synchronized oscillations of the neocortex. Furthermore, we show that correlations between neocortical and cerebellar LFPs persist in the awake animal, indicating that neocortical circuits modulate cerebellar neurons in a similar fashion in natural behavioral states. Thus, the projection neurons of the neocortex collectively exert a driving and modulatory influence on cerebellar network activity.

Ros, Hana; Sachdev, Robert N. S.; Yu, Yuguo; Sestan, Nenad; McCormick, David A.

2011-01-01

207

Early Childhood Obesity is Associated With Compromised Cerebellar Development  

Microsoft Academic Search

As part of a study investigating commonalities between Prader-Willi syndrome (PWS—a genetic imprinting disorder) and early-onset obesity of unknown etiology (EMO) we measured total cerebral and cerebellar volume on volumetric magnetic resonance imaging (MRI) images. Individuals with PWS (n = 16) and EMO (n = 12) had smaller cerebellar volumes than a control group of 15 siblings (p = .02

Jennifer L. Miller; Jessica Couch; Krista Schwenk; Michelle Long; Stephen Towler; Douglas W. Theriaque; Guojun He; Yijun Liu; Daniel J. Driscoll; Christiana M. Leonard

2009-01-01

208

Acute cerebellar ataxia with human parvovirus B19 infection  

Microsoft Academic Search

A 2 year old boy developed acute cerebellar ataxia in association with erythema infectiosum. During the disease, genomic DNA and antibodies against human parvovirus B19 were detected in serum but not in cerebrospinal fluid. Parvovirus B19 associated acute cerebellar ataxia might occur due to transient vascular reaction in the cerebellum during infection.

Yoshitaka Shimizu; Tamaki Ueno; Hiroshi Komatsu; Hiroshi Takada; Tadasu Nunoue

1999-01-01

209

Disconnection of cerebellar Purkinje cells in Kearns-Sayre syndrome  

Microsoft Academic Search

Kearns-Sayre syndrome (KSS) is a sporadic multisystem disorder due to rearrangements in mitochondrial DNA (mtDNA). To gain further insight into the pathogenesis of cerebellar dysfunction in KSS, antibodies against synaptophysin (SY) were used to identify presynaptic terminals and antibodies to calbindin D (CB) to identify Purkinje cells in the cerebellar cortex and in the dentate nucleus from two autopsied cases

Kurenai Tanji; Salvatore DiMauro; Eduardo Bonilla

1999-01-01

210

Distinct Critical Cerebellar Subregions for Components of Verbal Working Memory  

ERIC Educational Resources Information Center

|A role for the cerebellum in cognition has been proposed based on studies suggesting a profile of cognitive deficits due to cerebellar stroke. Such studies are limited in the determination of the detailed organisation of cerebellar subregions that are critical for different aspects of cognition. In this study we examined the correlation between…

Cooper, Freya E.; Grube, Manon; Von Kriegstein, Katharina; Kumar, Sukhbinder; English, Philip; Kelly, Thomas P.; Chinnery, Patrick F.; Griffiths, Timothy D.

2012-01-01

211

Generation of Cerebellar Interneurons from Dividing Progenitors in White Matter  

Microsoft Academic Search

The traditional view of the external granular layer of the cerebellar cortex giving rise to interneurons has been challenged by recent studies with quail-chick chimeras. To clarify the time and site of origins of interneurons, a retrovirus carrying the ?-galactosidase gene was injected into the deep cerebellar tissue or external granular layer of postnatal day 4\\/5 rats to label dividing

Lei Zhang; James E Goldman

1996-01-01

212

The Cerebellum and Language: Evidence from Patients with Cerebellar Degeneration  

ERIC Educational Resources Information Center

Clinical and imaging studies suggest that the cerebellum is involved in language tasks, but the extent to which slowed language production in cerebellar patients contributes to their poor performance on these tasks is not clear. We explored this relationship in 18 patients with cerebellar degeneration and 16 healthy controls who completed measures…

Stoodley, Catherine J.; Schmahmann, Jeremy D.

2009-01-01

213

Distinct Critical Cerebellar Subregions for Components of Verbal Working Memory  

ERIC Educational Resources Information Center

A role for the cerebellum in cognition has been proposed based on studies suggesting a profile of cognitive deficits due to cerebellar stroke. Such studies are limited in the determination of the detailed organisation of cerebellar subregions that are critical for different aspects of cognition. In this study we examined the correlation between…

Cooper, Freya E.; Grube, Manon; Von Kriegstein, Katharina; Kumar, Sukhbinder; English, Philip; Kelly, Thomas P.; Chinnery, Patrick F.; Griffiths, Timothy D.

2012-01-01

214

Evolution and ecology of directed aerial descent in arboreal ants.  

PubMed

Directed aerial descent (DAD) is used by a variety of arboreal animals to escape predators, to remain in the canopy, and to access resources. Here, we build upon the discovery of DAD in ants of tropical canopies by summarizing its known phylogenetic distribution among ant genera, and within both the subfamily Pseudomyrmecinae and the genus Cephalotes. DAD has multiple evolutionary origins in ants, occurring independently in numerous genera in the subfamilies Myrmicinae, Formicinae, and Pseudomyrmecinae. Ablation experiments and video recordings of ants in a vertical wind tunnel showed that DAD in Cephalotes atratus is achieved via postural changes, specifically orientation of the legs and gaster. The occurrence of DAD in Formicinae indicates that the presence of a postpetiole is not essential for the behavior. Evidence to date indicates that gliding behavior is accomplished by visual targeting mediated by the compound eyes, and is restricted to diurnally active ants that nest in trees. Occlusion of ocelli in Pseudomyrmex gracilis workers had no effect on their success or performance in gliding. Experimental assessment of the fate of ants that fall to the understory showed that ants landing in water are 15 times more likely to suffer lethal attacks than are ants landing in leaf litter. Variation in both the aerodynamic mechanisms and selective advantages of DAD merits further study given the broad taxonomic diversity of arboreal ants that engage in this intriguing form of flight. PMID:21562023

Yanoviak, Stephen P; Munk, Yonatan; Dudley, Robert

2011-05-11

215

STS-40 descent BET products: Development and results  

NASA Astrophysics Data System (ADS)

Descent Best Estimate Trajectory (BET) Data were generated for the final Orbiter Experiments Flight, STS-40. This report discusses the actual development of these post-flight products: the inertial BET, the Extended BET, and the Aerodynamic BET. Summary results are also included. The inertial BET was determined based on processing Tracking and Data Relay Satellite (TDRSS) coherent Doppler data in conjunction with observations from eleven C-band stations, to include data from the Kwajalein Atoll and the usual California coastal radars, as well as data from five cinetheodolite cameras in the vicinity of the runways at EAFB. The anchor epoch utilized for the trajectory reconstruction was 53,904 Greenwich Mean Time (GMT) seconds which corresponds to an altitude at epoch of approximately 708 kft. Atmospheric data to enable development of an Extended BET for this mission were upsurped from the JSC operational post-flight BET. These data were evaluated based on Space Shuttle-derived considerations as well as model comparisons. The Aerodynamic BET includes configuration information, final mass properties, and both flight-determined and predicted aerodynamic performance estimates. The predicted data were based on the final pre-operational databook, updated to include flight determined incrementals based on an earlier ensemble of flights. Aerodynamic performance comparisons are presented and correlated versus statistical results based on twenty-two previous missions.

Oakes, Kevin F.; Wood, James S.; Findlay, John T.

1991-11-01

216

Experimental Study of Rotor Vortex Wakes in Descent  

NASA Astrophysics Data System (ADS)

An experimental study is performed on a three-bladed rotor model in a water towing tank. The blade pitch and rotational velocity, the rotor plane angle of attack, and the carriage speed are all varied in order to simulate a wide range of rotorcraft operating states. Circulation Reynolds numbers are of order 105 and blade Reynolds numbers are of order 104. Flow visualization is done using air bubbles or dye injected from the blade tips to mark the vortex core, showing the development of an instability on the helical vortices in the wake. PIV data provide quantitative measures of the flow field as the wake develops. Strain gages are also used to record transient load measurements, allowing a correlation to be made between the rotor performance and the development of the vortex wake. The data so far indicate that as the instability develops, the adjacent vortices merge and form thick vortex rings, especially during descent. The vorticity spreads and is periodically shed from the wake, resulting in significant fluctuations in the rotor loading.

Stack, James; Carradonna, Frank; Savas, Omer

2002-11-01

217

PASDA - a tool to design atmospheric descent bodies with parachutes  

NASA Astrophysics Data System (ADS)

PASDA (Parachute System Design and Analysis Tool) is an unique integrated software package, funded by ESA, to design and analyse parachute based systems for space related applications and to provide the environment for collecting and storing parachute related information. PASDA supports future space science mission studies, where parachute systems are an essential part of the mission concept. Based on a sophisticated database of parachute related information for projects requiring descent in a planetary atmosphere, it assists the user in the selection, performance evaluation and specification of a parachute system for a specific mission. PASDA combines very different functions: trajectory simulation, parachute design and analysis, database tasks, graphical output, a sophisticated user interface, user guidance and software code to combine all functions. The parachute design package allows sizing of all parachute components e.g. canopy, lines, mortar, stowage volume, materials to be used, weight, etc. according to the loads derived in deployment and inflation analyses. Specific (parachute) knowledge is required to work efficiently with PASDA. However the integration of the different modules allows to let the computer perform the painstaking work of transforming outputs of one module into inputs for the next one and archiving results as numbers with description and graphics. Thus it provides an efficient integrated design and analysis approach to parachute system decelerators for studies of future space missions.

Adler, D.; Trogus, W.; Bachor, E.; Eiden, M.

1995-03-01

218

Direct Temperature Measurements during Netlander Descent on Mars  

NASA Astrophysics Data System (ADS)

A new design for a platinum thermoresistance temperature sensor has been developed and tested in Earth's atmosphere and stratosphere. It will be one of the sensors equipping the scientific package ATMIS (Atmospheric and Meteorology Instrument System), which will be devoted to the measurement of the meteorological parameters during both the entry/descent phase and the surface phase, aboard the Netlanders. In particular vertical profiles of temperature, density and pressure will allow the resolution of vertical gradients to investigate the atmospheric structure and dynamics. In view of the future missions to Mars, Netlander represents a unique chance to increase significantly the climate record both in time and in space, doubling the current knowledge of the atmospheric parameters. Furthermore is the only opportunity to conduct direct measurement of temperature and pressure (outside the boundary layer of the airbags used for the landing). The temperature sensor proposed is a platinum thermoresistance, enhancement of HASI TEM (Cassini/Huygens Mission); a substantial improvement of the performances, i.e. a faster dynamic response, has been obtained. Two different prototypes of new design sensor have been built, laboratory test are proceeding and the second one has been already flown aboard a stratospheric balloon.

Colombatti, G.; Angrilli, F.; Ferri, F.; Francesconi, A.; Fulchignoni, M.; Lion Stoppato, P. F.; Saggi, B.

1999-09-01

219

Chromosome stability in tonsillar squamous cell carcinoma is associated with HPV16 integration and indicates a favorable prognosis.  

PubMed

Tonsillar squamous cell carcinoma (TSCC) is frequently associated with human papillomavirus (HPV) and chromosome instability. Data from cellular model systems are, however, controversial concerning a relation between HPV and chromosome instability development. Here we studied this association in 77 primary TSCC with known clinical outcome and cell cycle protein expression profiles. Thirty-two tumors (42%) showed HPV16-integration. All 77 cases were analyzed by fluorescence in situ hybridization using chromosome 1- and 7-specific centromere DNA probes to detect chromosome instability, indicated by the presence of chromosome imbalances and/or polyploidization for these chromosomes. In addition, eight HPV-positive dysplasias, seven of which were adjacent to a carcinoma, were analyzed. Disomy for chromosome 1 and 7 was present in 29 out of 77 TSCC (38%), of which 19 were HPV16-positive (p = 0.002). Aneusomy was observed in the remaining 48 TSCC, of which 13 were HPV-positive. Aneusomies correlated significantly with tobacco- and alcohol consumption (p = 0.001 and p = 0.016, respectively) and a higher T-stage (p = 0.018). Both HPV-positivity and chromosome disomy were significantly associated with a favorable disease-free survival (p = 0.001 and p = 0.025, respectively). Particularly in the HPV16-positive group chromosome instability is a very strong indicator for an unfavorable prognosis (p = 0.032). In the dysplasias an identical HPV and chromosome copy number status was identified as in the adjacent tumors. We conclude that HPV-positive TSCC and their precursor lesions are more often genetically stable than HPV-negative lesions and that these tumors are associated with a favorable prognosis. Chromosome instability is an indicator for unfavorable prognosis, particularly in the HPV-positive patient group. PMID:22987500

Mooren, Jeroen J; Kremer, Bernd; Claessen, Sandra M H; Voogd, Adri C; Bot, Fredrik J; Peter Klussmann, J; Huebbers, Christian U; Hopman, Anton H N; Ramaekers, Frans C S; Speel, Ernst-Jan M

2012-10-11

220

Cerebellar abscess. A review of 47 cases.  

PubMed Central

Forty-seven cases of cerebellar abscess have been reviewed, 93% of which were secondary to otogenic disease. There has been little change in the annual incidence during the period of time under review. The overall mortality was 41%, but with successive decades the mortality has increased. Three factors appear to be of importance in determining survival: the patient's ability to control his infection; reduction of the effect of the posterior fossa mass, preferably by complete excision of the abscess under antibiotic cover; and, in the case of otogenic abscess, an adequate radical mastoidectomy with bone removal to the site of attachment of the abscess to the dura mater.

Shaw, M D; Russell, J A

1975-01-01

221

The cerebellar mutism syndrome and its relation to cerebellar cognitive function and the cerebellar cognitive affective disorder.  

PubMed

The postoperative cerebellar mutism syndrome (CMS), consisting of diminished speech output, hypotonia, ataxia, and emotional lability, occurs after surgery in up to 25% of patients with medulloblastoma and occasionally after removal of other posterior fossa tumors. Although the mutism is transient, speech rarely normalizes and the syndrome is associated with long-term adverse neurological, cognitive, and psychological sequelae. The clinical, neuroradiographic, and neuropsychological findings associated with CMS as well as possible mechanisms of injury are reviewed. Theories about the pathophysiology of CMS have evolved along with our understanding of the cerebellum as an important structure in the distributive neurocircuitry underlying complex speech, cognition, and behavior. CMS shares many similarities with the cerebellar cognitive affective syndrome, more commonly described in adults and consisting of disturbances of executive function, visuospatial skills, nonmotor language, and affect regulation. Future directions include more thorough neuropsychological characterization, functional and diffusion tensor imaging studies, and investigations into the underlying differences that may make some patients more vulnerable to CMS. PMID:18924161

Wells, Elizabeth M; Walsh, Karin S; Khademian, Zarir P; Keating, Robert F; Packer, Roger J

2008-01-01

222

New evidence for the cerebellar involvement in personality traits.  

PubMed

Following the recognition of its role in sensory-motor coordination and learning, the cerebellum has been involved in cognitive, emotional, and even personality domains. This study investigated the relationships between cerebellar macro- and micro-structural variations and temperamental traits measured by Temperament and Character Inventory (TCI). High resolution T1-weighted, and Diffusion Tensor Images of 100 healthy subjects aged 18-59 years were acquired by 3 Tesla Magnetic Resonance scanner. In multiple regression analyses, cerebellar Gray Matter (GM) or White Matter (WM) volumes, GM Mean Diffusivity (MD), and WM Fractional Anisotropy (FA) were used as dependent variables, TCI scores as regressors, gender, age, and education years as covariates. Novelty Seeking scores were associated positively with the cerebellar GM volumes and FA, and negatively with MD. No significant association between Harm Avoidance, Reward Dependence or Persistence scores and cerebellar structural measures was found. The present data put toward a cerebellar involvement in the management of novelty. PMID:24106465

Picerni, Eleonora; Petrosini, Laura; Piras, Fabrizio; Laricchiuta, Daniela; Cutuli, Debora; Chiapponi, Chiara; Fagioli, Sabrina; Girardi, Paolo; Caltagirone, Carlo; Spalletta, Gianfranco

2013-10-02

223

Cell death as a regulator of cerebellar histogenesis and compartmentation.  

PubMed

Programmed cell death is essential for the homeostasis of tissues and organs. During the development of the central nervous system, programmed cell death is highly regulated and restricted to distinct developmental time points of histogenesis. In this review, we will summarize recent data on the temporal and spatial distribution of programmed Purkinje cell death within the cerebellar cortex. We point out that programmed cell death within distinct regions of the developing cerebellar cortex differs by type and its cellular consequences. We submit the concept that local Purkinje cell death is important for late compartmentation of the cerebellar cortex and its wiring. To support this hypothesis, we provide new data obtained from a cerebellar mutant with prolonged expression of Engrailed-2 specifically in cerebellar Purkinje cells which shows increased local physiological cell death and concomitant changes in the pattern of afferent innervation. PMID:20941559

Jankowski, Jakob; Miething, Andreas; Schilling, Karl; Oberdick, John; Baader, Stephan

2011-09-01

224

New evidence for the cerebellar involvement in personality traits  

PubMed Central

Following the recognition of its role in sensory-motor coordination and learning, the cerebellum has been involved in cognitive, emotional, and even personality domains. This study investigated the relationships between cerebellar macro- and micro-structural variations and temperamental traits measured by Temperament and Character Inventory (TCI). High resolution T1-weighted, and Diffusion Tensor Images of 100 healthy subjects aged 18–59 years were acquired by 3 Tesla Magnetic Resonance scanner. In multiple regression analyses, cerebellar Gray Matter (GM) or White Matter (WM) volumes, GM Mean Diffusivity (MD), and WM Fractional Anisotropy (FA) were used as dependent variables, TCI scores as regressors, gender, age, and education years as covariates. Novelty Seeking scores were associated positively with the cerebellar GM volumes and FA, and negatively with MD. No significant association between Harm Avoidance, Reward Dependence or Persistence scores and cerebellar structural measures was found. The present data put toward a cerebellar involvement in the management of novelty.

Picerni, Eleonora; Petrosini, Laura; Piras, Fabrizio; Laricchiuta, Daniela; Cutuli, Debora; Chiapponi, Chiara; Fagioli, Sabrina; Girardi, Paolo; Caltagirone, Carlo; Spalletta, Gianfranco

2013-01-01

225

Supersonic Retropropulsion Technology Development in NASA's Entry, Descent, and Landing Project.  

National Technical Information Service (NTIS)

NASA's Entry, Descent, and Landing (EDL) space technology roadmap calls for new technologies to achieve human exploration of Mars in the coming decades (1). One of those technologies, termed Supersonic Retropropulsion (SRP), involves initiation of propuls...

A. Korzun A. A. Dyakonov B. Kelb D. G. Schauerhamer E. A. Post K. A. Zarchi K. T. Edquist M. N. Rhode S. A. Berry

2012-01-01

226

Final STS-35 Columbia Descent BET Products and Results for LaRC OEX Investigations.  

National Technical Information Service (NTIS)

Final STS-35 'Columbia' descent Best Estimate Trajectory (BET) products have been developed for Langley Research Center (LaRC) Orbiter Experiments (OEX) investigations. Included are the reconstructed inertial trajectory profile; the Extended BET, which co...

K. F. Oakes J. T. Findlay R. A. Jasinski J. S. Wood

1991-01-01

227

The Vega 1 and 2 probes - Operation of the descent modules in the Venus atmosphere  

Microsoft Academic Search

The Vega 1 and 2 descent modules entered the Venus atmosphere on June 11 and 15, 1985, respectively, at respective entry angles of 18.23 and 19.08 deg and entry velocities of 10.75 and 10.80 km\\/s. Consideration is given to the descent-module operations, including entry into the atmosphere, parachute deployment, jettisoning of the upper hemisphere, jettisoning of the lower hemisphere, jettisoning

V. A. Deriugin; V. P. Dolgopolov; V. P. Kariagin; V. M. Kovtunenko; P. S. Kremnev

1987-01-01

228

[Surgical decompression for massive cerebellar infarction].  

PubMed

The authors report 10 patients with progressive neurological deterioration due to massive cerebellar infarctions. Computerized tomography scans confirmed obstructive hydrocephalus and brain stem compression. All 10 patients (seven men, three women; mean age, 59 years) were treated by external ventricular drainage and decompressive suboccipital craniectomy. After discharge from the hospital, they were followed up (23-101 months) and their functional independence was evaluated by the Barthel Index. The condition of three patients with brain-stem infarction had deteriorated despite decompressive surgery. Two of these died during the acute stage and one because severely disabled. The remaining seven patients showed neurological improvement during the postoperative period. Four patients with preoperative Japan Coma Scale of 100 returned to their previous jobs within the follow-up period and three patients with preoperative Japan Coma Scale of 200 required some assistance in daily activities. It is suggested that decompressive surgery may be beneficial for massive cerebellar infarction. The postoperative prognosis depends mainly on the presence or absence of coexisting brain-stem infarction. It is possible that, without brain-stem infarction, patients who remained in a "dependent" state may have recovered better if they had been operated on earlier. PMID:7845519

Ogasawara, K; Koshu, K; Nagamine, Y; Fujiwara, S; Mizoi, K; Yoshimoto, T

1995-01-01

229

Differentiation of ES cells into cerebellar neurons.  

PubMed

The neuronal circuits of the cerebellar cortex are essential for motor and sensory learning, associative memory formation, and the vestibular ocular reflex. In children and young adults, tumors of the granule cell, the medulloblastomas, represent 40% of brain tumors. We report the differentiation of E14 ES cells into mature granule neurons by sequential treatment with secreted factors (WNT1, FGF8, and RA) that initiate patterning in the cerebellar region of the neural tube, bone morphogenic proteins (BMP6/7 and GDF7) that induce early granule cell progenitor markers (MATH1, MEIS1, ZIC1), mitogens (SHH, JAG1) that control proliferation and induce additional granule cell markers (Cyclin D2, PAX2/6), and culture in glial-conditioned medium to induce markers of mature granule neurons (GABAalpha(6)r), including ZIC2, a unique marker for granule neurons. Differentiated ES cells formed classic "T-shaped" granule cell axons in vitro, and implantation of differentiated Pde1c-Egfp-BAC transgenic ES cells into the external granule cell layer of neonatal mice resulted in the extension of parallel fibers, migration across the molecular layer, incorporation into the internal granule cell layer, and extension of short dendrites, typical of young granule cells forming synaptic connections with afferent mossy fibers. These results underscore the utility of treating ES cells with local, inductive signals that regulate CNS neuronal development in vivo as a strategy for cell replacement therapy of defined neuronal populations. PMID:17293457

Salero, Enrique; Hatten, Mary E

2007-02-09

230

Cyclic coordinate descent: A robotics algorithm for protein loop closure  

PubMed Central

In protein structure prediction, it is often the case that a protein segment must be adjusted to connect two fixed segments. This occurs during loop structure prediction in homology modeling as well as in ab initio structure prediction. Several algorithms for this purpose are based on the inverse Jacobian of the distance constraints with respect to dihedral angle degrees of freedom. These algorithms are sometimes unstable and fail to converge. We present an algorithm developed originally for inverse kinematics applications in robotics. In robotics, an end effector in the form of a robot hand must reach for an object in space by altering adjustable joint angles and arm lengths. In loop prediction, dihedral angles must be adjusted to move the C-terminal residue of a segment to superimpose on a fixed anchor residue in the protein structure. The algorithm, referred to as cyclic coordinate descent or CCD, involves adjusting one dihedral angle at a time to minimize the sum of the squared distances between three backbone atoms of the moving C-terminal anchor and the corresponding atoms in the fixed C-terminal anchor. The result is an equation in one variable for the proposed change in each dihedral. The algorithm proceeds iteratively through all of the adjustable dihedral angles from the N-terminal to the C-terminal end of the loop. CCD is suitable as a component of loop prediction methods that generate large numbers of trial structures. It succeeds in closing loops in a large test set 99.79% of the time, and fails occasionally only for short, highly extended loops. It is very fast, closing loops of length 8 in 0.037 sec on average.

Canutescu, Adrian A.; Dunbrack, Roland L.

2003-01-01

231

Experiments on liquid immiscibility along tholeiitic liquid lines of descent  

NASA Astrophysics Data System (ADS)

Crystallization experiments have been conducted on compositions along tholeiitic liquid lines of descent to define the compositional space for the development of silicate liquid immiscibility. Starting materials have 46-56 wt% SiO2, 11.7-17.7 wt% FeOtot, and Mg-number between 0.29 and 0.36. These melts fall on the basaltic trends relevant for Mull, Iceland, Snake River Plain lavas and for the Sept Iles layered intrusion, where large-scale liquid immiscibility has been recognized. At one atmosphere under anhydrous conditions, immiscibility develops below 1,000-1,020°C in all of these compositionally diverse lavas. Extreme iron enrichment is not necessary; immiscibility also develops during iron depletion and silica enrichment. Variations in melt composition control the development of silicate liquid immiscibility along the tholeiitic trend. Elevation of Na2O + K2O + P2O5 + TiO2 promotes the development of two immiscible liquids. Increasing melt CaO and Al2O3 stabilizes a single-liquid field. New data and published phase equilibria show that anhydrous, low-pressure fractional crystallization is the most favorable condition for unmixing during differentiation. Pressure inhibits immiscibility because it expands the stability field of high-Ca clinopyroxene, which reduces the proportion of plagioclase in the crystallizing assemblage, thus enhancing early iron depletion. Magma mixing between primitive basalt and Fe-Ti-P-rich ferrobasalts can serve to elevate phosphorous and alkali contents and thereby promote unmixing. Water might decrease the temperature and size of the two-liquid field, potentially shifting the binodal (solvus) below the liquidus, leading the system to evolve as a single-melt phase.

Charlier, Bernard; Grove, Timothy L.

2012-07-01

232

Analysis of atmospheric mesoscale models for entry, descent, and landing  

NASA Astrophysics Data System (ADS)

Each Mars Exploration Rover (MER) is sensitive to the Martian winds encountered near the surface during the entry, descent, and landing (EDL) process. These winds are strongly influenced by local (mesoscale) conditions. In the absence of suitable wind observations, wind fields predicted by Martian mesoscale atmospheric models have been analyzed to guide landing site selection. In order to encompass the available models and render them useful to the EDL engineering team, a series of statistical techniques was applied to the model results. These analyses cover the high-priority landing sites during the expected landing times (1200-1500 LT). The number of sites studied is limited by the computational and analysis cost of the mesoscale models. The statistical measures concentrate on the effective mean wind (the wind as seen by the landing system) and on the vertical structure of the horizontal winds. Both aspects are potentially hazardous to the MER landing system. In addition, a number of individual wind profiles from the mesoscale model were processed into a form that can be used directly by the EDL Monte Carlo simulations. The statistical analysis indicates that the Meridiani Planum and Elysium landing sites are probably safe. The Gusev Crater and Isidis Basin sites may be safe, but further analysis by the EDL engineers will be necessary to quantify the actual risk. Finally, the winds at the Melas Chasma landing site (and presumably other Valles Marineris landing sites) are dangerous. While the statistical parameters selected for these studies were primarily of engineering and safety interest, the techniques are potentially useful for more general scientific analyses. One interesting result of the current analysis is that the depth of the convective boundary layer (and thus the resulting energy density) appears to be primarily driven by the existence of a well-organized mesoscale (or regional) circulation, primarily driven by large-scale topographic features at Mars.

Kass, D. M.; Schofield, J. T.; Michaels, T. I.; Rafkin, S. C. R.; Richardson, M. I.; Toigo, A. D.

2003-11-01

233

Pharmacogenomics of warfarin in populations of African descent.  

PubMed

Warfarin is the most commonly prescribed oral anticoagulant worldwide despite its narrow therapeutic index and the notorious inter- and intra-individual variability in dose required for the target clinical effect. Pharmacogenetic polymorphisms are major determinants of warfarin pharmacokinetic and dynamics and included in several warfarin dosing algorithms. This review focuses on warfarin pharmacogenomics in sub-Saharan peoples, African Americans and admixed Brazilians. These 'Black' populations differ in several aspects, notably their extent of recent admixture with Europeans, a factor which impacts on the frequency distribution of pharmacogenomic polymorphisms relevant to warfarin dose requirement for the target clinical effect. Whereas a small number of polymorphisms in VKORC1 (3673G > A, rs9923231), CYP2C9 (alleles *2 and *3, rs1799853 and rs1057910, respectively) and arguably CYP4F2 (rs2108622), may capture most of the pharmacogenomic influence on warfarin dose variance in White populations, additional polymorphisms in these, and in other, genes (e.g. CALU rs339097) increase the predictive power of pharmacogenetic warfarin dosing algorithms in the Black populations examined. A personalized strategy for initiation of warfarin therapy, allowing for improved safety and cost-effectiveness for populations of African descent must take into account their pharmacogenomic diversity, as well as socio-economical, cultural and medical factors. Accounting for this heterogeneity in algorithms that are 'friendly' enough to be adopted by warfarin prescribers worldwide requires gathering information from trials at different population levels, but demands also a critical appraisal of racial/ethnic labels that are commonly used in the clinical pharmacology literature but do not accurately reflect genetic ancestry and population diversity. PMID:22676711

Suarez-Kurtz, Guilherme; Botton, Mariana R

2013-02-01

234

Agreement Rate of Rapid Urease Test, Conventional PCR, and Scorpion Real-Time PCR in Detecting Helicobacter Pylori from Tonsillar Samples of Patients with Chronic Tonsillitis  

PubMed Central

Background: Helicobacter pylori is capable of inducing systemic inflammatory reactions through immunological processes. There are several methods to identify the presence of H. pylori in clinical samples including rapid urease test (RUT), conventional polymerase chain reaction (PCR), and the Scorpion real-time PCR. Aim: The aim of the present study is to compare the agreement rate of these tests in identifying H. pylori in tonsillar biopsy specimens collected from patients with chronic tonsillitis. Materials and Methods: A total of 103 tonsil biopsy samples from patients with clinical signs of chronic tonsillitis were examined with RUT, PCR, and Scorpion real-time PCR. The degree of agreement between the three tests was later calculated. Results: There was a poor degree of agreement between RUT and PCR and also RUT and Scorpion real-time PCR (Kappa=0.269 and 0.249, respectively). In contrast with RUT, there was a strong degree of agreement between PCR and Scorpion real-time PCR (Kappa=0.970). Conclusion: The presence of a strong agreement between the Scorpion real-time PCR and PCR as well as its technical advantage over the conventional PCR assay, made the Scorpion real-time PCR an appropriate laboratory test to investigate the presence of H. pylori in tonsillar biopsy specimens in patients suffering from chronic tonsillitis.

Najafipour, Reza; Farivar, Taghi Naserpour; Pahlevan, Ali Akbar; Johari, Pouran; Safdarian, Farshid; Asefzadeh, Mina

2012-01-01

235

Recent binge drinking predicts smaller cerebellar volumes in adolescents.  

PubMed

The current study examined the effects of recent binge drinking on cerebellar morphometry in a sample of healthy adolescents. Participants were 106 teenagers (46 bingers and 60 controls) aged 16-19 who received a high-resolution magnetic resonance imaging (MRI) scan. FreeSurfer segmented and quantified the volume of each cerebellum. Maximum drinks during a binge in the past 3 months and duration since last binge were examined as predictors of cerebellar volume, after controlling for potentially confounding variables. In the 106 teens, higher peak drinks predicted smaller left hemisphere cerebellar gray and whitematter, and right hemisphere cerebellar gray matter, and marginally predicted smaller right hemisphere cerebellar white matter. Gender did not moderate these effects. More intense adolescent binge drinking is linked to smaller cerebellar volumes even in healthy teens, above and beyond variability attributable to risk factors for binge drinking. Longitudinal research is needed to see if cerebellar volumes worsen with protracted drinking and recover with abstinence. Interventions aimed at improving brain structure in adolescent binge drinkers are necessary given the high prevalence of risky drinking in youth. PMID:23154095

Lisdahl, Krista M; Thayer, Rachel; Squeglia, Lindsay M; McQueeny, Tim M; Tapert, Susan F

2012-11-13

236

Cerebellar processing of sensory inputs primes motor cortex plasticity.  

PubMed

Plasticity of the human primary motor cortex (M1) has a critical role in motor control and learning. The cerebellum facilitates these functions using sensory feedback. We investigated whether cerebellar processing of sensory afferent information influences the plasticity of the primary motor cortex (M1). Theta-burst stimulation protocols (TBS), both excitatory and inhibitory, were used to modulate the excitability of the posterior cerebellar cortex and to condition an ongoing M1 plasticity. M1 plasticity was subsequently induced in 2 different ways: by paired associative stimulation (PAS) involving sensory processing and TBS that exclusively involves intracortical circuits of M1. Cerebellar excitation attenuated the PAS-induced M1 plasticity, whereas cerebellar inhibition enhanced and prolonged it. Furthermore, cerebellar inhibition abolished the topography-specific response of PAS-induced M1 plasticity, with the effects spreading to adjacent motor maps. Conversely, cerebellar excitation had no effect on the TBS-induced M1 plasticity. This demonstrates the key role of the cerebellum in priming M1 plasticity, and we propose that it is likely to occur at the thalamic or olivo-dentate nuclear level by influencing the sensory processing. We suggest that such a cerebellar priming of M1 plasticity could shape the impending motor command by favoring or inhibiting the recruitment of several muscle representations. PMID:22351647

Popa, T; Velayudhan, B; Hubsch, C; Pradeep, S; Roze, E; Vidailhet, M; Meunier, S; Kishore, A

2012-02-20

237

Cerebellar cortical demyelination in the murine cuprizone model.  

PubMed

In multiple sclerosis, demyelination occurs beside the white-matter structures and in the cerebral and cerebellar cortex. We have previously shown that, in the cuprizone model, demyelination is present not only in the corpus callosum but also in the cerebral cortex. Here, we have performed a detailed analysis of the dynamics of de- and remyelination in the cerebellar cortex and white matter at nine timepoints in two cerebellar regions. To induce demyelination, C57BL/6 mice were fed with 0.2% cuprizone for 12 weeks followed by a recovery of 8 weeks. Both cortex and white-matter structures were significantly demyelinated after 12 weeks of cuprizone feeding. Remyelination occurred after withdrawal of cuprizone but was less prominent in the more caudal cerebellar region. Microglia infiltration was prominent in all analyzed cerebellar areas, preceding demyelination by approximately 2-4 weeks, and was delayed in the more caudal cerebellar region. Astrogliosis was also seen but did not reach the extent observed in the cerebrum. In summary, cuprizone feeding provides an excellent model for the investigation of de- and remyelination processes in the cerebellar cortex and white matter. Furthermore, demyelination, microglia and astrocyte changes were different in the cerebellum as compared with the cerebrum, indicating region-dependent pathomechanisms. PMID:19371354

Skripuletz, Thomas; Bussmann, Jens-Heiko; Gudi, Viktoria; Koutsoudaki, Paraskevi N; Pul, Refik; Moharregh-Khiabani, Darius; Lindner, Maren; Stangel, Martin

2009-04-07

238

Suspected inherited cerebellar neuroaxonal dystrophy in collie sheep dogs.  

PubMed

A cerebellar neuroaxonal dystrophy in working collie sheep dogs from two properties in New Zealand and one property in Australia is described. Clinical signs developed from 2-4 months of age and included hypermetria, wide-based stance, difficulty in maintaining balance, intention tremor and ataxia. Numerous spheroids, associated with mild Wallerian degeneration, were present in the central cerebellar, adjacent peduncular and folia white matter, and associated cerebellar roof and lateral vestibular nuclei. The history of several affected pups in litters from successive matings of the same sire and dam is suggestive of an autosomal recessive mode of inheritance. PMID:16030883

Clark, R G; Hartley, W J; Burgess, G S; Cameron, J S; Mitchell, G

1982-07-01

239

Ataxic hemiparesis with reductions of ipsilateral cerebellar blood flow  

SciTech Connect

Regional cerebellar blood flow was measured in a patient with left-sided ataxic hemiparesis, using single-photon emission computed tomography and N-isopropyl-p-(/sup 123/I)Iodoamphetamine. X-ray computed tomography revealed a small infarct in the paramedian portion of the right upper basis pontis. Blood flow was markedly reduced in the contralateral cerebellar hemisphere corresponding to the side of ataxia. The present study emphasizes the value of the three-dimensional functional imaging of the cerebellum to investigate the responsible lesion for ataxia and to study function of the cerebro-cerebellar circuits.

Sakai, F.; Aoki, S.; Kan, S.; Igarashi, H.; Kanda, T.; Tazaki, Y.

1986-09-01

240

Cerebellar abiotrophy in a family of Border Collie dogs.  

PubMed

Cerebellar abiotrophies have a nonsex-linked, autosomal, recessively inherited basis in a number of species, and lesions typically reflect profound and progressive loss of Purkinje cells. In this report, an unusual form of abiotrophy is described for two sibling Border Collies. Extensive loss of the cerebellar granular cell layer was present with relative sparing of Purkinje cells of two female pups. The biochemical basis for this form of cerebellar abiotrophy is unknown, but the lack of disease in other siblings supports an autosomal recessive mode of inheritance. PMID:12450206

Sandy, J R; Slocombe, R E; Mitten, R W; Jedwab, D

2002-11-01

241

Shake rattle and roll: the bony labyrinth and aerial descent in squamates.  

PubMed

Controlled aerial descent has evolved many times independently in vertebrates. Squamates (lizards and snakes) are unusual in that respect due to the large number of independent origins of the evolution of this behavior. Although some squamates such as flying geckos of the genus Ptychozoon and the flying dragons of the genus Draco show obvious adaptations including skin flaps or enlarged ribs allowing them to increase their surface area and slow down their descent, many others appear unspecialized. Yet, specializations can be expected at the level of the sensory and neural systems allowing animals to maintain stability during controlled aerial descent. The vestibular system is a likely candidate given that it is an acceleration detector and is well-suited to detect changes in pitch, roll and yaw. Here we use conventional and synchrotron ?CT scans to quantify the morphology of the vestibular system in squamates able to perform controlled aerial descent compared to species characterized by a terrestrial or climbing life style. Our results show the presence of a strong phylogenetic signal in the data with the vestibular system in species from the same family being morphologically similar. However, both our shape analysis and an analysis of the dimensions of the vestibular system showed clear differences among animals with different life-styles. Species able to perform a controlled aerial descent differed in the position and shape of the inner ear, especially of the posterior ampulla. Given the limited stability of squamates against roll and the fact that the posterior ampulla is tuned to changes in roll this suggests an adaptive evolution of the vestibular system in squamates using controlled aerial descent. Future studies testing for similar differences in other groups of vertebrates known to use controlled aerial descent are needed to test the generality of this observation. PMID:21700578

Boistel, Renaud; Herrel, Anthony; Lebrun, Renaud; Daghfous, Gheylen; Tafforeau, Paul; Losos, Jonathan B; Vanhooydonck, Bieke

2011-06-22

242

Chronic THC intake modifies fundamental cerebellar functions.  

PubMed

Delta9-tetrahydrocannabinol (THC), the principal bioactive component in the Cannabis plant, is truly a captivating drug. Acute and chronic THC intake produces a spectrum of biological effects ranging from transient psychotropic effects to prolonged medicinal benefits, many of which have been fostered for centuries by our society. In the July 2013 issue of the JCI, Cutando et al. combined mouse genetics with classic mouse behavioral analysis to deepen our understanding of the physiological consequence of subchronic THC intake on eyeblink reflexes, a fundamental neuronal adaptive response, revealing that this regimen leads to downregulation of the cannabinoid CB1 receptor (referred to as CB1 in the Cutando et al. article) in cerebellar stress fibers and the activation of microglia, raising provocative new questions about the safety profile of regimented THC intake. PMID:23863631

Stella, Nephi

2013-08-01

243

Past, Present and Future Therapeutics for Cerebellar Ataxias  

PubMed Central

Cerebellar ataxias are a group of disabling neurological disorders. Patients exhibit a cerebellar syndrome and can also present with extra-cerebellar deficits, namely pigmentary retinopathy, extrapyramidal movement disorders, pyramidal signs, cortical symptoms (seizures, cognitive impairment/behavioural symptoms), and peripheral neuropathy. Recently, deficits in cognitive operations have been unraveled. Cerebellar ataxias are heterogeneous both at the phenotypic and genotypic point of view. Therapeutical trials performed during these last 4 decades have failed in most cases, in particular because drugs were not targeting a deleterious pathway, but were given to counteract putative defects in neurotransmission. The identification of the causative mutations of many hereditary ataxias, the development of relevant animal models and the recent identifications of the molecular mechanisms underlying ataxias are impacting on the development of new drugs. We provide an overview of the pharmacological treatments currently used in the clinical practice and we discuss the drugs under development.

Marmolino, D; Manto, M

2010-01-01

244

Novel Approaches to Studying the Genetic Basis of Cerebellar Development  

PubMed Central

The list of genes that when mutated cause disruptions in cerebellar development is rapidly increasing. The study of both spontaneous and engineered mouse mutants has been essential to this progress, as it has revealed much of our current understanding of the developmental processes required to construct the mature cerebellum. Improvements in brain imaging, such as magnetic resonance imaging (MRI) and the emergence of better classification schemes for human cerebellar malformations, have recently led to the identification of a number of genes which cause human cerebellar disorders. In this review we argue that synergistic approaches combining classical molecular techniques, genomics, and mouse models of human malformations will be essential to fuel additional discoveries of cerebellar developmental genes and mechanisms.

Sajan, Samin A.; Waimey, Kathryn E.

2010-01-01

245

Genetics Home Reference: VLDLR-associated cerebellar hypoplasia  

MedlinePLUS

... this condition have an unusually small and underdeveloped cerebellum, which is the part of the brain that ... associated cerebellar hypoplasia? ataxia ; autosomal ; autosomal recessive ; cell ; cerebellum ; dysarthria ; gene ; hypoplasia ; lipoprotein ; malformation ; mental retardation ; population ; ...

246

Late Onset of Cerebellar Abiotrophy in a Boxer Dog  

PubMed Central

Cerebellar abiotrophy is a degenerative disorder of the central nervous system and has been reported in humans and animals. This case report documents clinical, histopathological, and immunohistochemical findings of cerebellar abiotrophy in an adult Boxer dog. A 3.5-year-old, female, tan Boxer dog presented with a six-week history of left-sided head tilt. Neurological examination and additional diagnostics during her three subsequent visits over 4.5 months revealed worsening of neurological signs including marked head pressing, severe proprioceptive deficits in all the four limbs, loss of menace response and palpebral reflex in the left eye, and a gradual seizure lasting one hour at her last visit. Based on the immunohistochemical staining for glial fibrillary acidic protein and histopathological examination of cerebellum, cerebellar cortical abiotrophy was diagnosed. This is the first reported case of cerebellar abiotrophy in a Boxer dog to our knowledge.

Gumber, Sanjeev; Cho, Doo-Youn; Morgan, Timothy W.

2010-01-01

247

Transient cerebellar mutism in the course of acute cerebellitis.  

PubMed

Transient mutism after posterior fossa surgery in children or associated with cerebellar hemorrhage or trauma is a recognized phenomenon. However, its association with parainflammatory cerebellitis has been rarely described. We report on a previously healthy 3-year-old child with severe cerebellitis after acute gastroenteritis of unidentified cause. Severe ataxia and transient mutism were the prevailing clinical features. Magnetic resonance imaging revealed swelling of the cerebellum with protruding cerebellar tonsils at the level of the occipital foramen. Recovery from the acute illness was slow and incomplete. Residual cerebellar dysfunction manifested with dysphonic and dysarthric speech, as well as motor coordination problems and was associated with atrophy of the vermis and cerebellar hemispheres in follow-up studies. PMID:14738957

Papavasiliou, Antigone S; Kotsalis, Charalambos; Trakadas, Stamos

2004-01-01

248

Global Patterns of Prostate Cancer Incidence, Aggressiveness, and Mortality in Men of African Descent  

PubMed Central

Prostate cancer (CaP) is the leading cancer among men of African descent in the USA, Caribbean, and Sub-Saharan Africa (SSA). The estimated number of CaP deaths in SSA during 2008 was more than five times that among African Americans and is expected to double in Africa by 2030. We summarize publicly available CaP data and collected data from the men of African descent and Carcinoma of the Prostate (MADCaP) Consortium and the African Caribbean Cancer Consortium (AC3) to evaluate CaP incidence and mortality in men of African descent worldwide. CaP incidence and mortality are highest in men of African descent in the USA and the Caribbean. Tumor stage and grade were highest in SSA. We report a higher proportion of T1 stage prostate tumors in countries with greater percent gross domestic product spent on health care and physicians per 100,000 persons. We also observed that regions with a higher proportion of advanced tumors reported lower mortality rates. This finding suggests that CaP is underdiagnosed and/or underreported in SSA men. Nonetheless, CaP incidence and mortality represent a significant public health problem in men of African descent around the world.

Rebbeck, Timothy R.; Devesa, Susan S.; Chang, Bao-Li; Bunker, Clareann H.; Cheng, Iona; Cooney, Kathleen; Eeles, Rosalind; Fernandez, Pedro; Giri, Veda N.; Gueye, Serigne M.; Haiman, Christopher A.; Henderson, Brian E.; Heyns, Chris F.; Hu, Jennifer J.; Ingles, Sue Ann; Isaacs, William; Jalloh, Mohamed; John, Esther M.; Kibel, Adam S.; Kidd, LaCreis R.; Layne, Penelope; Leach, Robin J.; Neslund-Dudas, Christine; Okobia, Michael N.; Ostrander, Elaine A.; Park, Jong Y.; Patrick, Alan L.; Phelan, Catherine M.; Ragin, Camille; Roberts, Robin A.; Rybicki, Benjamin A.; Stanford, Janet L.; Strom, Sara; Thompson, Ian M.; Witte, John; Xu, Jianfeng; Yeboah, Edward; Hsing, Ann W.; Zeigler-Johnson, Charnita M.

2013-01-01

249

Global patterns of prostate cancer incidence, aggressiveness, and mortality in men of african descent.  

PubMed

Prostate cancer (CaP) is the leading cancer among men of African descent in the USA, Caribbean, and Sub-Saharan Africa (SSA). The estimated number of CaP deaths in SSA during 2008 was more than five times that among African Americans and is expected to double in Africa by 2030. We summarize publicly available CaP data and collected data from the men of African descent and Carcinoma of the Prostate (MADCaP) Consortium and the African Caribbean Cancer Consortium (AC3) to evaluate CaP incidence and mortality in men of African descent worldwide. CaP incidence and mortality are highest in men of African descent in the USA and the Caribbean. Tumor stage and grade were highest in SSA. We report a higher proportion of T1 stage prostate tumors in countries with greater percent gross domestic product spent on health care and physicians per 100,000 persons. We also observed that regions with a higher proportion of advanced tumors reported lower mortality rates. This finding suggests that CaP is underdiagnosed and/or underreported in SSA men. Nonetheless, CaP incidence and mortality represent a significant public health problem in men of African descent around the world. PMID:23476788

Rebbeck, Timothy R; Devesa, Susan S; Chang, Bao-Li; Bunker, Clareann H; Cheng, Iona; Cooney, Kathleen; Eeles, Rosalind; Fernandez, Pedro; Giri, Veda N; Gueye, Serigne M; Haiman, Christopher A; Henderson, Brian E; Heyns, Chris F; Hu, Jennifer J; Ingles, Sue Ann; Isaacs, William; Jalloh, Mohamed; John, Esther M; Kibel, Adam S; Kidd, Lacreis R; Layne, Penelope; Leach, Robin J; Neslund-Dudas, Christine; Okobia, Michael N; Ostrander, Elaine A; Park, Jong Y; Patrick, Alan L; Phelan, Catherine M; Ragin, Camille; Roberts, Robin A; Rybicki, Benjamin A; Stanford, Janet L; Strom, Sara; Thompson, Ian M; Witte, John; Xu, Jianfeng; Yeboah, Edward; Hsing, Ann W; Zeigler-Johnson, Charnita M

2013-02-13

250

Autosomal dominant cerebellar ataxias in the Kinki area of Japan  

Microsoft Academic Search

Summary The autosomal dominant cerebellar ataxias are a heterogeneous group of neurodegenerative disorders characterized by slowly progressive cerebellar ataxia. Recently, among the ataxias, spinocerebellar ataxia type 1 (SCA1), Machado-Joseph disease (MJD) and dentatorubral-pallidoluysian atrophy have been found to be caused by expansion of a CAG trinucleotide repeat in the coding region of the disease genes. We have analyzed the CAG

Ryusuke Matsumura; Tetsuya Takayanagi; Kayoko Murata; Naonobu Futamura; Yasuyo Fujimoto

1996-01-01

251

Two proteins associated with cerebellar hypoplasia in jaundiced Gunn rats  

Microsoft Academic Search

Two cerebellar proteins with apparent molecular weights of 250,000 (GR-250) and 50,000 (GR-50) are closely associated with cerebellar hypoplasia in jaundiced homozygous Gunn rats. These proteins, found in Gunn rat cerebellum (4–60 days of age) and cerebrum as well as staggerer mouse cerebellum, were studied with electrophoretic techniques. After 8 days of life, GR-250 decreased and GR-50 increased in the

Sachiko Aono; Hiroshi Sato; Reiji Semba; Shigeo Kashiwamata

1983-01-01

252

Cerebellar contributions to verbal working memory: beyond cognitive theory  

Microsoft Academic Search

Neuropsychological findings together with recent advances in neuroanatomical and neuroimaging techniques have spurred the\\u000a investigation of cerebellar contributions to cognition. One cognitive process that has been the focus of much research is\\u000a working memory, in particular its verbal component. Influenced by Baddeley’s cognitive theory of working memory, cerebellar\\u000a activation during verbal working memory tasks has been predominantly attributed to the

Gal Ben-Yehudah; Sara Guediche; Julie A. Fiez

2007-01-01

253

Peripheral nerve involvement in hereditary cerebellar and multisystem degenerative disorders.  

PubMed

Hereditary ataxias (HA) encompass an increasing number of degenerative disorders characterized by progressive cerebellar ataxia usually accompanied by extracerebellar semeiology including peripheral nerve involvement. Classically, HA were classified according to their pathological hallmark comprising three main forms: (1) spinal form predominantly with degeneration of spinocerebellar tracts, posterior columns, and pyramidal tracts (Friedreich's ataxia, FA); (2) olivopontocerebellar atrophy (OPCA); and (3) cortical cerebellar atrophy (CCA). In the 1980s Harding proposed a clinico-genetic classification based upon age of onset, modality of transmission, and clinical semeiology. The main categories in this classification were as follows: (1) early onset cerebellar ataxia (EOCA) with age of onset below 25 years and usually with autosomal recessive (AR) transmission (this group encompasses FA and syndromes different from FA); (2) autosomal dominant cerebellar ataxia (ADCA) with adult onset and with either cerebellar-plus syndrome or pure cerebellar semeiology; and (3) idiopathic late onset onset cerebellar ataxia (ILOCA). With the advent of molecular genetics, the nosology of HA has been in a state of constant flux. At present EOCA comprises at least 17 genotypes (designated with the acronym of ARCA derived from AR cerebellar ataxia), whereas under the umbrella of ADCA 30 genotypes have been reported. In this chapter we will review peripheral nerve involvement in classical pathological entities (OPCA and CCA), ARCA, ADCA, and ILOCA paying special attention to the most prevalent syndromes in each category. As a general rule, nerve involvement is relatively common in any form of ataxia except ILOCA, the most common pattern being either sensory or sensorimotor neuronopathy with a dying-back process. An exception to this rule is AR spastic ataxia of Charlevoix-Saguenay where nerve conduction studies show the characteristic pattern of intermediate neuropathy implying that sacsin mutation causes both axonal and Schwann cell dysfunction. PMID:23931821

Berciano, José; García, Antonio; Infante, Jon

2013-01-01

254

Treatment of cerebellar ataxia with 5HT1A agonist  

Microsoft Academic Search

Effective, pharmacologic approaches to the treatment of cerebellar ataxia are lacking or inadequate. We recently reported\\u000a preliminary evidence that tandospirone citrate (tandospirone), a 5-HT1A agonist, improved cerebellar ataxia in patients with\\u000a Machado-Joseph disease (MJD). In the course of that study, we found that such treatment also alleviated the pain associated\\u000a with cold sensations in the legs, insomnia, anorexia, and depression,

Asako Takei; Takeshi Hamada; Ichiro Yabe; Hidenao Sasaki

2005-01-01

255

Cerebellar transcranial magnetic stimulation impairs verbal working memory  

Microsoft Academic Search

Previous functional magnetic resonance imaging and patient studies indicate cerebellar participation in verbal working memory. In particular, event-related functional magnetic resonance imaging showed superior cerebellar activation during the initial encoding phase of the Sternberg task. This study used functional magnetic resonance imaging-guided trans- cranial magnetic stimulation (TMS) to test whether disruption of the right superior cerebellum (hemispheric lobule VI\\/Crus I)

John E. Desmond; S. H. Annabel Chen; Perry B. Shieh

2005-01-01

256

Cerebellar Theta-Burst Stimulation Selectively Enhances Lexical Associative Priming  

Microsoft Academic Search

Recent research in cerebellar cognitive and linguistic functions makes plausible the idea that the cerebellum is involved\\u000a in processing temporally contiguous linguistic input. In order to assess this hypothesis, a simple lexical decision task was\\u000a constructed to study whether the effect of transcranial magnetic stimulation on two different cerebellar sites would have\\u000a a selective impact on associative as opposed to

Giorgos P. Argyropoulos

257

Modulatory Effects of Theta Burst Stimulation on Cerebellar Nonsomatic Functions  

Microsoft Academic Search

Clinical and functional imaging studies suggest that the cerebellar vermis is involved in the regulation of a range of nonsomatic\\u000a functions including cardiovascular control, thirst, feeding behavior, and primal emotions. Cerebello-hypothalamic circuits\\u000a have been postulated to be a potential neuroanatomical substrate underlying this modulation. We tested this putative relationship\\u000a between the cerebellar vermis and nonsomatic functions by stimulating the cerebellum

Asli Demirtas-Tatlidede; Catarina Freitas; Alvaro Pascual-Leone; Jeremy D. Schmahmann

258

TRPC3 channel underlies cerebellar long-term depression.  

PubMed

Cerebellar long-term depression (LTD) is induced by repetitive pairing of both synaptic inputs provided by climbing fibers (CFs) and parallel fibers (PFs), especially when CF stimulation followed by burst of PFs. Metabotropic glutamate receptor type 1 (mGluR1)-dependent signaling in Purkinje cells is critically involved in the induction of cerebellar LTD. Signaling pathway of mGluR1 has two limbs: one is IP3 receptor-mediated Ca release from intracellular Ca store and the other is activation of transient receptor potential canonical (TRPC) channels. Here, we hypothesized that TRPC3, which is reported to be responsible for mGluR1-evoked slow currents, mediates the induction of the cerebellar LTD. Purkinje cells were loaded with antibodies which act against a cytoplasmic epitope of TRPC3 channels, acting as a specific antagonist of TRPC3. About 30 min after achieving a whole-cell configuration, mGluR1-evoked slow currents were significantly reduced; a possible cause of this time delay might be the diffusion time course from patch pipette to the dendrite site of mGluR1 activation. Taking this delay into consideration, we next attempted to induce cerebellar LTD by pairing PFs and CF. It was found that cerebellar LTD was hindered in the presence of TRPC3 antibodies. Taken together, our data suggest that TRPC3 activation may be essential for the induction of LTD in cerebellar Purkinje cells. PMID:23408143

Kim, Sang Jeong

2013-06-01

259

Emotions and their cognitive control in children with cerebellar tumors.  

PubMed

A constellation of deficits, termed the cerebellar cognitive affective syndrome (CCAS), has been reported following acquired cerebellar lesions. We studied emotion identification and the cognitive control of emotion in children treated for acquired tumors of the cerebellum. Participants were 37 children (7-16 years) treated for cerebellar tumors (19 benign astrocytomas (AST), 18 malignant medulloblastomas (MB), and 37 matched controls (CON). The Emotion Identification Task investigated recognition of happy and sad emotions in music. In two cognitive control tasks, we investigated whether children could identify emotion in situations in which the emotion in the music and the emotion in the lyrics was either congruent or incongruent. Children with cerebellar tumors identified emotion as accurately and quickly as controls (p > .05), although there was a significant interaction of emotions and group (p < .01), with the MB group performing less accurately identifying sad emotions, and both cerebellar tumor groups were impaired in the cognitive control of emotions (p < .01). The fact that childhood acquired cerebellar tumors disrupt cognitive control of emotion rather than emotion identification provides some support for a model of the CCAS as a disorder, not so much of emotion as of the regulation of emotion by cognition. PMID:20887648

Hopyan, Talar; Laughlin, Suzanne; Dennis, Maureen

2010-10-04

260

A descent method for computing the Tikhonov regularized solution of linear inverse problems  

NASA Astrophysics Data System (ADS)

In this paper we describe an iterative algorithm, called Descent-TCG, based on truncated Conjugate Gradient iterations to compute Tikhonov regularized solutions of linear ill-posed problems. Suitable termination criteria are built-up to define an inner-outer iteration scheme for the computation of a regularized solution. Numerical experiments are performed to compare the algorithm with other well-established regularization methods. We observe that the best Descent-TCG results occur for highly noised data and we always get fairly reliable solutions, preventing the dangerous error growth often appearing in other well-established regularization methods. Finally, the Descent-TCG method is computationally advantageous especially for large size problems.

Zama, Fabiana; Loli Piccolomini, Elena; Landi, Germana

2004-10-01

261

Evolutionary analyses of non-genealogical bonds produced by introgressive descent  

PubMed Central

All evolutionary biologists are familiar with evolutionary units that evolve by vertical descent in a tree-like fashion in single lineages. However, many other kinds of processes contribute to evolutionary diversity. In vertical descent, the genetic material of a particular evolutionary unit is propagated by replication inside its own lineage. In what we call introgressive descent, the genetic material of a particular evolutionary unit propagates into different host structures and is replicated within these host structures. Thus, introgressive descent generates a variety of evolutionary units and leaves recognizable patterns in resemblance networks. We characterize six kinds of evolutionary units, of which five involve mosaic lineages generated by introgressive descent. To facilitate detection of these units in resemblance networks, we introduce terminology based on two notions, P3s (subgraphs of three nodes: A, B, and C) and mosaic P3s, and suggest an apparatus for systematic detection of introgressive descent. Mosaic P3s correspond to a distinct type of evolutionary bond that is orthogonal to the bonds of kinship and genealogy usually examined by evolutionary biologists. We argue that recognition of these evolutionary bonds stimulates radical rethinking of key questions in evolutionary biology (e.g., the relations among evolutionary players in very early phases of evolutionary history, the origin and emergence of novelties, and the production of new lineages). This line of research will expand the study of biological complexity beyond the usual genealogical bonds, revealing additional sources of biodiversity. It provides an important step to a more realistic pluralist treatment of evolutionary complexity.

Bapteste, Eric; Lopez, Philippe; Bouchard, Frederic; Baquero, Fernando; McInerney, James O.; Burian, Richard M.

2012-01-01

262

Evolutionary analyses of non-genealogical bonds produced by introgressive descent.  

PubMed

All evolutionary biologists are familiar with evolutionary units that evolve by vertical descent in a tree-like fashion in single lineages. However, many other kinds of processes contribute to evolutionary diversity. In vertical descent, the genetic material of a particular evolutionary unit is propagated by replication inside its own lineage. In what we call introgressive descent, the genetic material of a particular evolutionary unit propagates into different host structures and is replicated within these host structures. Thus, introgressive descent generates a variety of evolutionary units and leaves recognizable patterns in resemblance networks. We characterize six kinds of evolutionary units, of which five involve mosaic lineages generated by introgressive descent. To facilitate detection of these units in resemblance networks, we introduce terminology based on two notions, P3s (subgraphs of three nodes: A, B, and C) and mosaic P3s, and suggest an apparatus for systematic detection of introgressive descent. Mosaic P3s correspond to a distinct type of evolutionary bond that is orthogonal to the bonds of kinship and genealogy usually examined by evolutionary biologists. We argue that recognition of these evolutionary bonds stimulates radical rethinking of key questions in evolutionary biology (e.g., the relations among evolutionary players in very early phases of evolutionary history, the origin and emergence of novelties, and the production of new lineages). This line of research will expand the study of biological complexity beyond the usual genealogical bonds, revealing additional sources of biodiversity. It provides an important step to a more realistic pluralist treatment of evolutionary complexity. PMID:23090996

Bapteste, Eric; Lopez, Philippe; Bouchard, Frédéric; Baquero, Fernando; McInerney, James O; Burian, Richard M

2012-10-22

263

Eye Movement Patterns of the Elderly during Stair Descent:Effect of Illumination  

NASA Astrophysics Data System (ADS)

The relationship between the eye movement pattern during stair descent and illumination was studied in 4 elderly people in comparison with that in 5 young people. The illumination condition was light (85.0±30.9 lx) or dark (0.7±0.3 lx), and data of eye movements were obtained using an eye mark recorder. A flight of 15 steps was used for the experiment, and data on 3 steps in the middle, on which the descent movements were stabilized, were analyzed. The elderly subjects pointed their eyes mostly directly in front in the facial direction regardless of the illumination condition, but the young subjects tended to look down under the light condition. The young subjects are considered to have confirmed the safety of the front by peripheral vision, checked the stepping surface by central vision, and still maintained the upright position without leaning forward during stair descent. The elderly subjects, in contrast, always looked at the visual target by central vision even under the light condition and leaned forward. The range of eye movements was larger vertically than horizontally in both groups, and a characteristic eye movement pattern of repeating a vertical shuttle movement synchronous with descent of each step was observed. Under the dark condition, the young subjects widened the range of vertical eye movements and reduced duration of fixation. The elderly subjects showed no change in the range of eye movements but increased duration of fixation during stair descent. These differences in the eye movements are considered to be compensatory reactions to narrowing of the vertical visual field, reduced dark adaptation, and reduced dynamic visual acuity due to aging. These characteristics of eye movements of the elderly lead to an anteriorly leaned posture and lack of attention to the front during stair descent.

Kasahara, Satoko; Okabe, Sonoko; Nakazato, Naoko; Ohno, Yuko

264

Defective cerebellar control of cortical plasticity in writer's cramp.  

PubMed

A large body of evidence points to a role of basal ganglia dysfunction in the pathophysiology of dystonia, but recent studies indicate that cerebellar dysfunction may also be involved. The cerebellum influences sensorimotor adaptation by modulating sensorimotor plasticity of the primary motor cortex. Motor cortex sensorimotor plasticity is maladaptive in patients with writer's cramp. Here we examined whether putative cerebellar dysfunction in dystonia is linked to these patients' maladaptive plasticity. To that end we compared the performances of patients and healthy control subjects in a reaching task involving a visuomotor conflict generated by imposing a random deviation (-40° to 40°) on the direction of movement of the mouse/cursor. Such a task is known to involve the cerebellum. We also compared, between patients and healthy control subjects, how the cerebellum modulates the extent and duration of an ongoing sensorimotor plasticity in the motor cortex. The cerebellar cortex was excited or inhibited by means of repeated transcranial magnetic stimulation before artificial sensorimotor plasticity was induced in the motor cortex by paired associative stimulation. Patients with writer's cramp were slower than the healthy control subjects to reach the target and, after having repeatedly adapted their trajectories to the deviations, they were less efficient than the healthy control subjects to perform reaching movement without imposed deviation. It was interpreted as impaired washing-out abilities. In healthy subjects, cerebellar cortex excitation prevented the paired associative stimulation to induce a sensorimotor plasticity in the primary motor cortex, whereas cerebellar cortex inhibition led the paired associative stimulation to be more efficient in inducing the plasticity. In patients with writer's cramp, cerebellar cortex excitation and inhibition were both ineffective in modulating sensorimotor plasticity. In patients with writer's cramp, but not in healthy subjects, behavioural parameters reflecting their capacity for adapting to the rotation and for washing-out of an earlier adaptation predicted the efficacy of inhibitory cerebellar conditioning to influence sensorimotor plasticity: the better the online adaptation, the smaller the influence of cerebellar inhibitory stimulation on motor cortex plasticity. Altered cerebellar encoding of incoming afferent volleys may result in decoupling the motor component from the afferent information flow, and also in maladjusted sensorimotor calibration. The loss of cerebellar control over sensorimotor plasticity might also lead to building up an incorrect motor program to specific adaptation tasks such as writing. PMID:23801734

Hubsch, Cecile; Roze, Emmanuel; Popa, Traian; Russo, Margherita; Balachandran, Ammu; Pradeep, Salini; Mueller, Florian; Brochard, Vanessa; Quartarone, Angelo; Degos, Bertrand; Vidailhet, Marie; Kishore, Asha; Meunier, Sabine

2013-07-01

265

Aerothermodynamics calculation of thermal destruction of "Fregat" upper stage at descent in the Earth's atmosphere  

NASA Astrophysics Data System (ADS)

The engineering calculation method has been developed for investigation of the process of thermal destruction of "Fregat" upper stage at deorbiting and descent into the Earth's atmosphere. The results of calculation of its descent trajectory and characteristics of aerodynamic heating are presented. Within the framework of the thermodynamic approach, the authors investigated the process of pressure increase in the tanks due to heating and evaporation of the liquid phase of fuel. Stresses in the shells, the height and the energy equivalent of explosive destruction of tanks were calculated depending on the degree of their filling with remains of the components of liquid fuel.

Glazunov, A. A.; Goldin, V. D.; Zverev, V. G.; Ustinov, S. N.; Finchenko, V. S.

2013-06-01

266

Aprosencephaly and cerebellar dysgenesis in SIBS  

SciTech Connect

Aprosencephaly is a rare, lethal malformation sequence of the central nervous system that has been attributed to a postneuralation encephaloclastic process. We describe autopsy findings consistent with aprosencephaly in 2 fetuses conceived from a consanguineous mating (first cousins). Both showed anecephalic manifestations; however, the crania were intact, with fused sutures. The neuropathologic findings were essentially identical. Each fetus had complete absence of the telecephalon and pyramidal tracts, rudimentary diencephalic and mesencephalic structures, primitive cerebellar hemispheres, posterolateral clusters of primitive neural cells in the medullas suggesting an abnormality of neural migration, a normally-formed spinal cord, and retinal dysplasia within normally-formed globes. In addition, both fetuses manifested a peculiar perivascular mesenchymal proliferation seen only within the central nervous system. The similarity of these cases, coupled with parental consanguinity, suggests a primary malformation in brain development due to the homozygous representation of a mutant allele. We hypothesize that these patients may represent a defect in a gene important in brain development, the nature of which has yet to be elucidated. 26 refs., 4 figs., 4 tabs.

Florell, S.R.; Townsend, J.J.; Klatt, E.C. [Univ. of Utah Health Sciences Center, Salt Lake City, UT (United States)] [and others

1996-06-28

267

Sudden stopping in patients with cerebellar ataxia.  

PubMed

Stopping during walking, a dynamic motor task frequent in everyday life, is very challenging for ataxic patients, as it reduces their gait stability and increases the incidence of falls. This study was conducted to analyse the biomechanical characteristics of upper and lower body segments during abrupt stopping in ataxic patients in order to identify possible strategies used to counteract the instability in the sagittal and frontal plane. Twelve patients with primary degenerative cerebellar ataxia and 12 age- and sex-matched healthy subjects were studied. Time-distance parameters, dynamic stability of the centre of mass, upper body measures and lower joint kinematic and kinetic parameters were analysed. The results indicate that ataxic patients have a great difficulty in stopping abruptly during walking and adopt a multi-step stopping strategy, occasionally with feet parallel, to compensate for their inability to coordinate the upper body and to generate a well-coordinated lower limb joint flexor-extensor pattern and appropriate braking forces for progressively decelerating the progression of the body in the sagittal plane. A specific rehabilitation treatment designed to improve the ability of ataxic patients to transform unplanned stopping into planned stopping, to coordinate upper body and to execute an effective flexion-extension pattern of the hip and knee joints may be useful in these patients in order to improve their stopping performance and prevent falls. PMID:23512116

Serrao, Mariano; Conte, Carmela; Casali, Carlo; Ranavolo, Alberto; Mari, Silvia; Di Fabio, Roberto; Perrotta, Armando; Coppola, Gianluca; Padua, Luca; Monamě, Stefano; Sandrini, Giorgio; Pierelli, Francesco

2013-10-01

268

Vitamin B12 status in patients of Turkish and Dutch descent with depression: a comparative cross-sectional study  

Microsoft Academic Search

BACKGROUND: Studies have shown a clear relationship between depressive disorders and vitamin B12 deficiency. Gastroenteritis and Helicobacter pylori infections can cause vitamin B12 deficiency. Helicobacter pylori infections are not uncommon among people of Turkish descent in The Netherlands. AIM: To examine the frequency of vitamin B12 deficiency in depressive patients of Turkish descent and compare it to the frequency of

Yener Güzelcan; Peter van Loon

2009-01-01

269

14 CFR 121.333 - Supplemental oxygen for emergency descent and for first aid; turbine engine powered airplanes...  

Code of Federal Regulations, 2010 CFR

... 2009-01-01 false Supplemental oxygen for emergency descent and for first aid...Requirements § 121.333 Supplemental oxygen for emergency descent and for first aid...the certificate holder shall furnish oxygen and dispensing equipment to comply...

2009-01-01

270

14 CFR 121.333 - Supplemental oxygen for emergency descent and for first aid; turbine engine powered airplanes...  

Code of Federal Regulations, 2010 CFR

... 2010-01-01 false Supplemental oxygen for emergency descent and for first aid...Requirements § 121.333 Supplemental oxygen for emergency descent and for first aid...the certificate holder shall furnish oxygen and dispensing equipment to comply...

2010-01-01

271

Structural basis of cerebellar microcircuits in the rat.  

PubMed

The topography of the cerebellar cortex is described by at least three different maps, with the basic units of each map termed "microzones," "patches," and "bands." These are defined, respectively, by different patterns of climbing fiber input, mossy fiber input, and Purkinje cell (PC) phenotype. Based on embryological development, the "one-map" hypothesis proposes that the basic units of each map align in the adult animal and the aim of the present study was to test this possibility. In barbiturate anesthetized adult rats, nanoinjections of bidirectional tracer (Retrobeads and biotinylated dextran amine) were made into somatotopically identified regions within the hindlimb C1 zone in copula pyramidis. Injection sites were mapped relative to PC bands defined by the molecular marker zebrin II and were correlated with the pattern of retrograde cell labeling within the inferior olive and in the basilar pontine nuclei to determine connectivity of microzones and patches, respectively, and also with the distributions of biotinylated dextran amine-labeled PC terminals in the cerebellar nuclei. Zebrin bands were found to be related to both climbing fiber and mossy fiber inputs and also to cortical representation of different parts of the ipsilateral hindpaw, indicating a precise spatial organization within cerebellar microcircuitry. This precise connectivity extends to PC terminal fields in the cerebellar nuclei and olivonuclear projections. These findings strongly support the one-map hypothesis and suggest that, at the microcircuit level of resolution, the cerebellar cortex has a common plan of spatial organization for major inputs, outputs, and PC phenotype. PMID:24133249

Cerminara, Nadia L; Aoki, Hanako; Loft, Michaela; Sugihara, Izumi; Apps, Richard

2013-10-16

272

Cerebellar involvement in motor but not sensory adaptation  

PubMed Central

Predictable sensorimotor perturbations can lead to cerebellum-dependent adaptation—i.e., recalibration of the relationship between sensory input and motor output. Here we asked if the cerebellum is also needed to recalibrate the relationship between two sensory modalities, vision and proprioception. We studied how people with and without cerebellar damage use visual and proprioceptive signals to estimate their hand’s position when the sensory estimates disagree. Theoretically, the brain may resolve the discrepancy by recalibrating the relationship between estimates (sensory realignment). Alternatively, the misalignment may be dealt with by relying less on one sensory estimate and more on the other (a weighting strategy). To address this question, we studied subjects with cerebellar damage and healthy controls as they performed a series of tasks. The first was a prism adaptation task that involves motor adaptation to compensate for a visual perturbation and is known to require the cerebellum. As expected, people with cerebellar damage were impaired relative to controls. The same subjects then performed two experiments in which they reached to visual and proprioceptive targets while a visuoproprioceptive misalignment was gradually imposed. Surprisingly, cerebellar patients performed as well as controls when the task invoked only sensory realignment, but were impaired relative to controls when motor adaptation was also possible. Additionally, individuals with cerebellar damage were able to use a weighting strategy similarly to controls. These results demonstrate that, unlike motor adaptation, sensory realignment and weighting are not cerebellum-dependent.

Block, Hannah J.; Bastian, Amy J.

2012-01-01

273

Three-dimensional microsurgical anatomy of cerebellar peduncles.  

PubMed

The microsurgical anatomy of cerebellar peduncles and their relationships with neighbouring fasciculi were investigated by using a fibre dissection technique. As the dissection progressed, photographs of each progressive layer were obtained and stereoscopic images were created using the 3D anaglyphic method. These findings provided the anatomical basis for a conceptual division of cerebellar peduncles into segments. The middle cerebellar peduncle (MCP) was divided into two segments: cisternal and intracerebellar segments. The inferior cerebellar peduncle (ICP) was divided into three segments: cisternal, ventricular and intracerebellar segments. The superior cerebellar peduncle (SCP) was divided into three segments: intracerebellar, intermediate and intrategmental segments. The fibre dissection technique disclosed a constant course of peduncular fibres inside the white core of the cerebellum. The pontocerebellar fibres of the MCP pass over and laterally to the bundles of the ICP and SCP. The centripetal fibres of the ICP wrap around the radiation of the SCP and the dentate nucleus, directed towards the cortex of the vermis. The centrifugal bundle of the SCP ascends towards the mesencephalon where it sinks passing below the fibres the lateral lemniscus. The knowledge gained by studying the intrinsic anatomy of the cerebellum is useful to accomplish appropriate surgical planning and, ultimately, to understand the repercussions of surgical procedures on the white matter tracts in this region. PMID:22933248

Perrini, Paolo; Tiezzi, Giacomo; Castagna, Maura; Vannozzi, Riccardo

2012-08-30

274

Neuroimaging Evidence of Cerebellar Involvement in Premenstrual Dysphoric Disorder  

PubMed Central

Background Premenstrual dysphoric disorder (PMDD) is a debilitating cyclic disorder that is characterized by affective symptoms, including irritability, depression, and anxiety which arise in the luteal phase of the menstrual cycle and resolve soon after the onset of menses. Despite a prevalence of up to 8% in women of reproductive age, few studies have investigated the brain mechanisms that underlie this disorder. Methods We used positron emission tomography with [18F] fluorodeoxyglucose and self-report questionnaires to assess cerebral glucose metabolism and mood in 12 women with PMDD and 12 healthy comparison subjects in the follicular and late luteal phases of the menstrual cycle. The primary biological endpoint was incorporated regional cerebral radioactivity (scaled to the global mean) as an index of glucose metabolism. Relationships between regional brain activity and mood ratings were assessed. Blood samples were taken before each session for assay of plasma estradiol and progesterone concentrations. Results There were no group differences in hormone levels in either the follicular or late luteal phase, but the groups differed in the effect of menstrual phase on cerebellar activity. Women with PMDD, but not comparison subjects, showed an increase in cerebellar activity (particularly in the right cerebellar vermis) from the follicular phase to the late luteal phase (p = 0.003). In the PMDD group, this increase in cerebellar activity was correlated with worsening of mood (p = 0.018). Conclusions These findings suggest that the midline cerebellar nuclei, which have been implicated in other mood disorders, also contribute to negative mood in PMDD.

Rapkin, Andrea J.; Berman, Steven M.; Mandelkern, Mark A.; Silverman, Daniel H. S.; Morgan, Melinda; London, Edythe D.

2010-01-01

275

Interval Timing Disruptions in Subjects with Cerebellar Lesions  

PubMed Central

The cerebellum has long been implicated in time perception, particularly in the subsecond range. The current set of studies examines the role of the cerebellum in suprasecond timing, using analysis of behavioral data in subjects with cerebellar lesions. Eleven cerebellar lesion subjects and 17 controls were tested on temporal estimation, reproduction and production, for times ranging from 2 to 12 s. Cerebellar patients overproduced times on both the reproduction and production tasks; the effect was greatest at the shortest duration. A subset of patients also underestimated intervals. Cerebellar patients were significantly more variable on the estimation and reproduction tasks. No significant differences between normal and cerebellar patients were found on temporal discrimination tasks with either sub- or suprasecond times. Patients with damage to the lateral superior hemispheres or the dentate nuclei showed more significant impairments than those with damage elsewhere in the cerebellum, and patients with damage to the left cerebellum had more significant differences from controls than those with damage to the right. These data suggest that damage to the middle-to-superior lobules or the left hemisphere is especially detrimental to timing suprasecond intervals. We suggest that this region be considered part of a network of brain structures including the DLPFC that is crucial for interval timing.

Gooch, Cynthia M.; Wiener, Martin; Wencil, Elaine B.; Coslett, H. Branch

2009-01-01

276

Thalamic, brainstem, and cerebellar glucose metabolism in the hemiplegic monkey  

SciTech Connect

Unilateral ablation of cerebral cortical areas 4 and 6 of Brodmann in the macaque monkey results in a contralateral hemiplegia that resolves partially with time. During the phase of dense hemiplegia, local cerebral metabolic rate for glucose (1CMRG1c) is decreased significantly in most of the thalamic nuclei ipsilateral to the ablation, and there are slight contralateral decreases. The lCMRGlc is reduced bilaterally in most of the brainstem nuclei and bilaterally in the deep cerebellar nuclei, but only in the contralateral cerebellar cortex. During the phase of partial motor recovery, lCMRGlc is incompletely restored in many of the thalamic nuclei ipsilateral to the ablation and completely restored in the contralateral nuclei. In the brainstem and deep cerebellar nuclei, poor to moderate recovery occurs bilaterally. Moderate recovery occurs in the contralateral cerebellar cortex. The findings demonstrate that a unilateral cerebral cortical lesion strongly affects lCMRGlc in the thalamus ipsilaterally and in the cerebellar cortex contralaterally, but in the brainstem bilaterally. Partial recovery of lCMRGlc accompanies the progressive motor recovery. The structures affected include those with direct, and also those with indirect, connections to the areas ablated.

Shimoyama, I.; Dauth, G.W.; Gilman, S.; Frey, K.A.; Penney, J.B. Jr.

1988-12-01

277

Does a basic deficit in force control underlie cerebellar ataxia?  

PubMed

Because damage to the cerebellum results in characteristic movement incoordination known as "ataxia," it has been hypothesized that it is involved in estimation of limb dynamics that occur during movement. However, cerebellar function may extend beyond movement to force control in general, with or without movement. Here we tested whether the cerebellum is involved in controlling force separate from estimating limb dynamics and whether ataxia could result from a deficit in force control. We studied patients with cerebellar ataxia controlling their arm force isometrically; in this condition arm dynamics are absent and there is no need for (or effect from an impairment in) estimations of limb dynamics. Subjects were required to control their force magnitude, direction, or both. Cerebellar patients were able to match force magnitude or direction similarly to control subjects. Furthermore, when controlling force magnitude, they intuitively chose directions (not specified) that required minimal effort at the joint level--this ability was also similar to control subjects. In contrast, cerebellar patients performed significantly worse than control subjects when asked to match both force magnitude and direction. This was surprising, since they did not exhibit significant impairment in doing either in isolation. These results show that cerebellum-dependent computations are not limited to estimations of body dynamics needed for active movement. Deficits occur even in isometric conditions, but apparently only when multiple degrees of freedom must be controlled simultaneously. Thus a fundamental cerebellar operation may be combining/coordinating degrees of freedom across many kinds of movements and behaviors. PMID:23175807

Charles, Steven K; Okamura, Allison M; Bastian, Amy J

2012-11-21

278

Structural Basis of Cerebellar Microcircuits in the Rat  

PubMed Central

The topography of the cerebellar cortex is described by at least three different maps, with the basic units of each map termed “microzones,” “patches,” and “bands.” These are defined, respectively, by different patterns of climbing fiber input, mossy fiber input, and Purkinje cell (PC) phenotype. Based on embryological development, the “one-map” hypothesis proposes that the basic units of each map align in the adult animal and the aim of the present study was to test this possibility. In barbiturate anesthetized adult rats, nanoinjections of bidirectional tracer (Retrobeads and biotinylated dextran amine) were made into somatotopically identified regions within the hindlimb C1 zone in copula pyramidis. Injection sites were mapped relative to PC bands defined by the molecular marker zebrin II and were correlated with the pattern of retrograde cell labeling within the inferior olive and in the basilar pontine nuclei to determine connectivity of microzones and patches, respectively, and also with the distributions of biotinylated dextran amine-labeled PC terminals in the cerebellar nuclei. Zebrin bands were found to be related to both climbing fiber and mossy fiber inputs and also to cortical representation of different parts of the ipsilateral hindpaw, indicating a precise spatial organization within cerebellar microcircuitry. This precise connectivity extends to PC terminal fields in the cerebellar nuclei and olivonuclear projections. These findings strongly support the one-map hypothesis and suggest that, at the microcircuit level of resolution, the cerebellar cortex has a common plan of spatial organization for major inputs, outputs, and PC phenotype.

Cerminara, Nadia L.; Aoki, Hanako; Loft, Michaela; Apps, Richard

2013-01-01

279

What Teacher Education Programs Can Learn From Successful Mexican-Descent Students  

Microsoft Academic Search

This study explored the high school experiences of 32 Mexican-descent students who had successfully graduated and were enrolled in institutions of higher learning. By conducting extended interviews with these students, the author sought to identify teachers' actions that the students found helpful or harmful to their learning experiences. These observations can be used to make recommendations for better preparing preservice

Craig A. Hughes

2003-01-01

280

Heritage Learners of Mexican Descent in Higher Education: A Qualitative Study of Past and Present Experiences  

ERIC Educational Resources Information Center

|This is a qualitative interpretive study that explores the past and present experiences of heritage learners (HLs) of Mexican descent who were studying or had recently studied advanced Spanish in institutions of higher education. All of the participants had been exposed to Spanish in the home and began their studies in elementary or middle school…

Gignoux, Alicia

2009-01-01

281

Cardiac Structure and Exercise Blood Pressure in Urban and Rural Canadian Men of Icelandic Descent  

Microsoft Academic Search

The objective of the study was to determine the relationship between exercise systolic blood pressure (ESBP), during bicycle ergometry, and echocardiographically determined left ventricular structure in rural and urban Canadian men of Icelandic descent. The study was cross-sectional in design. The settings were urban Winnipeg and the rural Interlake District in the province of Manitoba, Canada. Subjects were adult male

Barbara J. Naimark; Arnold Naimark; Robert B. Tate; Stefan B. Sigurdsson; Johann Axelsson

1996-01-01

282

Descent of long-lived trace gases in the water polar vortex  

Microsoft Academic Search

Recent observations of CH4 and HF from the UARS Halogen Limb Occulation Experiment (HALOE) suggest that vigorous descent occurs within the polar winter vortex with ``mesospheric'' values of CH4 evident down to 30 mbar. This study shows that a highly accurate two-dimensional model advection scheme coupled with a modern radiation scheme, parameterized planetary and gravity wave drag algorithms can produce

Julio T. Bacmeister; Mark R. Schoeberl; Michael E. Summers; Joan R. Rosenfield; Xun Zhu

1995-01-01

283

Carrier Screening for Genetic Disorders in Individuals of Ashkenazi Jewish Descent  

Microsoft Academic Search

Objective: To give recommendations to physicians and midwives providing pre-conception or prenatal care about carrier screening for genetic disorders in individuals of Ashkenazi Jewish descent. Options: To offer carrier screening for Tay-Sachs disease (TSD) only or to expand the screening to include other disorders known to occur with increased frequency in the Ashkenazi Jewish population.

Sylvie Langlois; R. Douglas Wilson; Victoria M. Allen; Claire Blight; Valerie A. Désilets; Montreal QC; Alain Gagnon; Gregory J. Reid; Anne Summers; Philip Wyatt; David Chitayat; Albert E. Chudley; Sandra Farrell; Michael T. Geraghty; Chumei Li; Sarah M. Nikkel; Frederique Tihy

2006-01-01

284

Irish descent, religion and food consumption in the west of Scotland  

Microsoft Academic Search

Mortality and morbidity of people of Irish descent in Britain is high, including from cardiovascular causes potentially linked with diet. The west of Scotland has long had a pattern of Irish migration, where migrants were poorer than the host population, and their different religious background gave rise to prolonged discrimination. This paper uses data collected in 1987\\/88 from the west

K. Mullen; R. Williams; K. Hunt

2000-01-01

285

Feeling Frugal: Socioeconomic Status, Acculturation, and Cultural Health Beliefs Among Women of Mexican Descent  

Microsoft Academic Search

Psychosocial and socioeconomic variables are often confounded. The authors combined quantitative with grounded theory analysis to investigate influences of acculturation, socioeconomic status (SES), and cultural health beliefs on Mexican-descent women's preventive health behaviors. In 5 focus group interviews sampling across levels of acculturation and SES, women expressing more traditional Mexican health beliefs about breast cancer screening were of lower SES

Evelinn A. Borrayo; Sharon Rae Jenkins

2003-01-01

286

Showing Up, Remaining Engaged, and Partaking as Students: Resilience Among Students of Mexican Descent  

Microsoft Academic Search

This paper examines the ways in which 12 high school students of Mexican descent remain resilient amid difficult and stressful realities. Through an examination of students' interview responses, a case is made that students' ability to engage in school and figure out everyday ways to partake as students are signs of resilience. This work suggests the need to shift from

Teresa Sosa

2012-01-01

287

Model reference adaptive control of a maglev system with stable maximum descent criterion  

Microsoft Academic Search

This paper develops a model-reference adaptive controller (MRC) design framework for magnetically suspended vehicles (maglev) using the criterion of stable maximum descent. The adaptation algorithm is constrained to reduce the airgap error between the reference model and the actual system. The explicit relationship between the parameters of the performance criterion (function of the airgap error and its derivative) and the

P. K. Sinha; Alexandre N. Pechev

1999-01-01

288

Optimal learning rates for each pattern and neuron in gradient descent training of multilayer perceptrons  

Microsoft Academic Search

Proposes optimal learning rates in gradient descent training of multilayer perceptrons, which are a separate learning rate for weights associated with each neuron and a separate one for assigning virtual hidden targets associated with each training pattern. That is, a hidden weight vector has two optimal learning rates, one for assigning virtual hidden targets and the other for minimizing a

Sang-Hoon Oh; Soo-Young Lee

1999-01-01

289

Gender effects on Mexican-descent parents' questions and scaffolding during toy play: a sequential analysis  

Microsoft Academic Search

Parental responses following children's answers to parental questions (Parent Question ? Child Answer ? Parent Response) were examined during play between Mexican-descent children and their parents. Nineteen boys and 18 girls were videotaped playing separately with each of their parents with a toy zoo set. Patterns of parental responses following children's answers to parental questions indicated that mothers provided more

Harriet R. Tenenbaum; Campbell Leaper

1998-01-01

290

Static Lung Volumes: Reference Values from a Latin Population of Spanish Descent  

Microsoft Academic Search

Background and Objectives: The aim of this study was to develop a set of prediction equations and 90% confidence intervals for static lung volumes using the multibreath helium equilibration method from a sample of asymptomatic Caucasian subjects of Spanish descent. Moreover, these equations were compared with those of previous studies. Methods: Measurements of static lung volumes using techniques recommended by

Pedro J. Cordero; Pilar Morales; Eduardo Benlloch; Luis Miravet; Javier Cebrian

1999-01-01

291

Impact of multiple submarine channels on the descent of dense water at high latitudes  

Microsoft Academic Search

A three-dimensional numerical hydrodynamic model is applied to examine the impact of multiple submarine channels (<10 km across, <100 m deep), common to most continental margins of the ocean, on the descent of dense water at high latitudes. The model consists of an ocean bottom layer of constant height that follows variable bottom topography under constant vertical grid spacing. An

Jochen Kämpf

2000-01-01

292

Access to Health Care Among Latinos of Mexican Descent in "Colonias" in Two Texas Counties  

ERIC Educational Resources Information Center

Critical to resolving the problem of health disparities among Latinos is examining the needs within ethnic subpopulations. This paper focused on the unique challenges encountered by one ethnic subpopulation -- Latinos of Mexican descent living in colonias. Findings reaffirm the importance of looking within ethnic subpopulations to understand the…

Ortiz, Larry; Arizmendi, Lydia; Cornelius, Llewellyn J.

2004-01-01

293

Critical spacecraft-to-Earth communications for Mars Exploration Rover (MER) entry, descent and landing  

Microsoft Academic Search

For planetary lander missions, the most challenging phase of the spacecraft to ground communications is during the entry, descent, and landing (EDL). As each 2003 Mars Exploration Rover (MER) enters the Martian atmosphere, it slows dramatically. The extreme acceleration and jerk cause extreme Doppler dynamics on the X-band signal received on Earth. When the vehicle slows sufficiently, the parachute is

William J. Hurd; P. Estabrook; C. S. Racho; E. H. Satorius

2002-01-01

294

Statistical Reconstruction of Mars Entry, Descent, and Landing Trajectories and Atmospheric Profiles  

Microsoft Academic Search

Accurate post-flight reconstruction of a vehicle's trajectory during entry into a planetary atmosphere can produce a wide array of valuable information. The data collected through the reconstruction of entry, descent, and landing system performance enables the quantification of performance margins for future systems. Beyond the engineering knowledge gained through trajectory reconstruction, the results may also be used by planetary scientists

John A. Christian; Amanda M. Verges; Robert D. Braun

2007-01-01

295

Design optimisation and flight validation of a stratospheric descent low cost probe in scientific balloon missions  

Microsoft Academic Search

This paper summarises the activities conducted at CISAS - University of Padova in designing and optimising a low cost scientific probe to be used in earth atmospheric descents from balloon reached stratospheric altitudes of around 40 kilometre. As part of the collaboration with Italian Space Agency on HASI instrument for Huygens mission, University of Padova has been conducting for several

C. B. Carlo Bettanini; G. C. Giacomo Colombatti; F. A. Francesco Angrilli; G. B. Giannandrea Bianchini; E. F. Enrico Flamini

2004-01-01

296

Situating middle class identities: American college women of South Asian descent  

Microsoft Academic Search

This article explores the ways in which American college women of South Asian descent discuss their positioning as middle class. The article analyses participants' talk around class as evidence of embeddedness in American class discourses and a complex and contradictory scheme of identification that implicates other identities like gender, race and culture. Respondents often articulated class using the American Dream,

Rachel L. Finn

2009-01-01

297

A descent method with inexact linear search for nonsmooth equilibrium problems  

NASA Astrophysics Data System (ADS)

A descent method with respect to the gap function is formulated and justified for the nonsmooth equilibrium problem. It uses the procedure of inexact linear search of the Armijo type. The proposed method converges under the same assumptions as the methods with exact linear search.

Konnov, I. V.; Pinyagina, O. V.

2008-10-01

298

The behavior of epididymis, processus vaginalis and testicular descent in cryptorchid boys treated with buserelin.  

PubMed

This randomized double-blind, placebo-controlled study was initiated to analyze the behavior of epididymis, processus vaginalis and testicular descent in cryptorchid boys treated with a low dose (20 micrograms) of a luteinizing hormone-releasing hormone analogue (Buserelin), administered daily, as a nasal spray, for a short period (28 days). Fifty-nine true cryptorchid boys were randomly assigned to 3 groups: buserelin treatment [22], surgical treatment [18] or placebo control group [19]. The 3 groups of patients were similar before treatment in regard to testicular position, chronological and bone age, height and weight, luteinizing hormone, follicle-stimulating hormone, testosterone, penile size and the volume of the contralateral descended testis. None of the patients had retractile testes. Buserelin significantly induced testicular descent compared to the boys treated with a placebo (P < 0.01). A normal epididymis was found more often in boys with successful descent (P < 0.003). A closed processus vaginalis was also more frequently observed in the group treated with buserelin than in surgically treated one (P < 0.05). In conclusion, buserelin was capable of inducing testicular descent besides provoking further development of the epididymis and closing the processus vaginalis. PMID:8101813

Bica, D T; Hadziselimovic, F

1993-01-01

299

High-resolution detection of identity by descent in unrelated individuals.  

PubMed

Detection of recent identity by descent (IBD) in population samples is important for population-based linkage mapping and for highly accurate genotype imputation and haplotype-phase inference. We present a method for detection of recent IBD in population samples. Our method accounts for linkage disequilibrium between SNPs to enable full use of high-density SNP data. We find that our method can detect segments of a length of 2 cM with moderate power and negligible false discovery rate in Illumina 550K data in Northwestern Europeans. We compare our method with GERMLINE and PLINK, and we show that our method has a level of resolution that is significantly better than these existing methods, thus extending the usefulness of recent IBD in analysis of high-density SNP data. We survey four genomic regions in a sample of UK individuals of European descent and find that on average, at a given location, our method detects IBD in 2.7 per 10,000 pairs of individuals in Illumina 550K data. We also present methodology and results for detection of homozygosity by descent (HBD) and survey the whole genome in a sample of 1373 UK individuals of European descent. We detect HBD in 4.7 individuals per 10,000 on average at a given location. Our methodology is implemented in the freely available BEAGLE software package. PMID:20303063

Browning, Sharon R; Browning, Brian L

2010-03-18

300

High-Resolution Detection of Identity by Descent in Unrelated Individuals  

PubMed Central

Detection of recent identity by descent (IBD) in population samples is important for population-based linkage mapping and for highly accurate genotype imputation and haplotype-phase inference. We present a method for detection of recent IBD in population samples. Our method accounts for linkage disequilibrium between SNPs to enable full use of high-density SNP data. We find that our method can detect segments of a length of 2 cM with moderate power and negligible false discovery rate in Illumina 550K data in Northwestern Europeans. We compare our method with GERMLINE and PLINK, and we show that our method has a level of resolution that is significantly better than these existing methods, thus extending the usefulness of recent IBD in analysis of high-density SNP data. We survey four genomic regions in a sample of UK individuals of European descent and find that on average, at a given location, our method detects IBD in 2.7 per 10,000 pairs of individuals in Illumina 550K data. We also present methodology and results for detection of homozygosity by descent (HBD) and survey the whole genome in a sample of 1373 UK individuals of European descent. We detect HBD in 4.7 individuals per 10,000 on average at a given location. Our methodology is implemented in the freely available BEAGLE software package.

Browning, Sharon R.; Browning, Brian L.

2010-01-01

301

MCAV\\/IMU integrated navigation for the powered descent phase of Mars EDL  

Microsoft Academic Search

Pin-point landing is considered as a key technology for future manned Mars landing and Mars base missions. The traditional inertial navigation system (INS) based guidance, navigation and control (GNC) mode used in the Mars entry, descent and landing (EDL) phase has no ability to achieve the precise and safe Mars landing, so novel EDL GNC methodologies should be investigated to

Shuang Li; Yuming Peng; Yuping Lu; Liu Zhang; Yufei Liu

2010-01-01

302

Martian Atmosphere in the Landing Site of the Descent Module of MARS-6 (Preliminary Results).  

National Technical Information Service (NTIS)

On 12 March 1974 the Mars-6 station reached the vicinity of Mars and after terminal correction, its descent module was separated from it. Preliminary analysis of all measurements shows that an atmosphere with the following parameters fits the proposed mod...

V. S. Avduyevskiy E. L. Akim V. I. Aleshin N. F. Borodin V. V. Kerzhanovich

1975-01-01

303

Access to Health Care Among Latinos of Mexican Descent in "Colonias" in Two Texas Counties  

ERIC Educational Resources Information Center

|Critical to resolving the problem of health disparities among Latinos is examining the needs within ethnic subpopulations. This paper focused on the unique challenges encountered by one ethnic subpopulation -- Latinos of Mexican descent living in colonias. Findings reaffirm the importance of looking within ethnic subpopulations to understand the…

Ortiz, Larry; Arizmendi, Lydia; Cornelius, Llewellyn J.

2004-01-01

304

Qualitative Research with an Understudied Population: In-Depth Interviews with Women of Mexican Descent  

Microsoft Academic Search

Community-based qualitative research offers advantages for study of populations that are understudied and not well understood, but qualitative methodology presents major challenges. This article examines some of these challenges, illustrated by a study of pregnancy and childbearing among women of Mexican descent. Issues addressed in this article include culture and gender relevance, access to the population, representativeness, skilled interviewers, trust

Margaret Sherrard Sherraden; Rossana E. Barrera

1995-01-01

305

A Terminal Descent Sensor Trade Study Overview for the Orion Landing and Recovery System  

Microsoft Academic Search

This trade study was conducted as a part of the Orion landing system advanced development project to determine possible terminal descent sensor (TDS) architectures that could be used for a rocket assisted landing system. Several technologies were considered for the Orion TDS including radar, lidar, GPS applications, mechanical sensors, and gamma ray altimetry. A preliminary down selection occurred by comparing

Catherine Dunn; Ravi Prakash

2008-01-01

306

Education by Any Means Necessary: Peoples of African Descent and Community-Based Pedagogical Spaces  

ERIC Educational Resources Information Center

|This study examines how and why peoples of African descent access and utilize community-based pedagogical spaces that exist outside schools. Employing a theoretical framework that fuses historical methodology and border-crossing theory, the researchers review existing scholarship and primary documents to present an historical examination of how…

Douglas, Ty-Ron Michael; Peck, Craig

2013-01-01

307

Pattern recognition using a family of design algorithms based upon the generalized probabilistic descent method  

Microsoft Academic Search

This paper provides a comprehensive introduction to a novel approach to pattern recognition which is based on the generalized probabilistic descent method (GPD) and its related design algorithms. The paper contains a survey of recent recognizer design techniques, the formulation of GPD, the concept of minimum classification error learning that is closely related to the GPD formalization, a relational analysis

SHIGERU KATAGIRI; Biing-Hwang Juang; Chin-Hui Lee

1998-01-01

308

Stabilization of a Reentry Vehicle by a Partial Spin-up during Uncontrolled Descent  

Microsoft Academic Search

Stabilization of a reentry vehicle (RV) by a partial spin-up of it is considered for the case of uncontrolled descent into the atmosphere. In this case, the vehicle is a composite construction consisting of two rigid bodies, a return capsule and a stabilizing block, which is put in rotation. A model is developed for the spatial motion of the reentry

V. S. Aslanov; A. V. Doroshin

2002-01-01

309

A Critical Analysis of Western Perspectives on Families of Arab Descent  

ERIC Educational Resources Information Center

|Western research on families of Arab descent has increased in the current decade, compared to the previous 30 years. In this review of 256 empirical articles, through a critical postcolonial lens, domestic violence and family planning were the two most established areas of study. Generally, samples have come from a small group of countries such…

Beitin, Ben K.; Allen, Katherine R.; Bekheet, Maureen

2010-01-01

310

Exponential convergence of a gradient descent algorithm for a class of recurrent neural networks  

Microsoft Academic Search

This paper considers the convergence of an approximate gradient descent back propagation algorithm for a one hidden layer neural network whose output is an affine combination of certain nonlinear functions of the outputs of biased infinite impulse response affine systems. We give a persistent excitation condition that guarantees local convergence of the algorithm. We show that this condition holds for

Peter Bartlett; S. Dasgupta

1995-01-01

311

Attitudes toward homosexuality among U.S. residents of Mexican descent  

Microsoft Academic Search

This study examined attitudes toward lesbians and gay men in a sample of northern California residents of Mexican descent (N = 616), using 3?item versions of the Attitudes Toward Gay Men (ATG) and Attitudes Toward Lesbians (ATL) scales presented simultaneously in Spanish and English. Males’ attitudes toward homosexual men were significantly more negative than females’ attitudes, whereas females expressed relatively

Gregory M. Herek

2006-01-01

312

Multiple time scale sliding mode control of reusable launch vehicles in ascent and descent modes  

Microsoft Academic Search

A reusable launch vehicle control problem during ascent and descent is addressed via multiple-time scaled continuous sliding mode control. The proposed sliding mode controller utilizes a two-loop structure and provides robust decoupled tracking of both orientation angle command profiles and angular rate command profiles in the presence of bounded external disturbances and plant uncertainties, including aerodynamic surfaces and engine failures.

Yu. B. Shtessel; C. E. Hall

2001-01-01

313

Spread of cattle led to the loss of matrilineal descent in Africa: a coevolutionary analysis.  

PubMed Central

Matrilineal descent is rare in human societies that keep large livestock. However, this negative correlation does not provide reliable evidence that livestock and descent rules are functionally related, because human cultures are not statistically independent owing to their historical relationships (Galton's problem). We tested the hypothesis that when matrilineal cultures acquire cattle they become patrilineal using a sample of 68 Bantu- and Bantoid-speaking populations from sub-Saharan Africa. We used a phylogenetic comparative method to control for Galton's problem, and a maximum-parsimony Bantu language tree as a model of population history. We tested for coevolution between cattle and descent. We also tested the direction of cultural evolution--were cattle acquired before matriliny was lost? The results support the hypothesis that acquiring cattle led formerly matrilineal Bantu-speaking cultures to change to patrilineal or mixed descent. We discuss possible reasons for matriliny's association with horticulture and its rarity in pastoralist societies. We outline the daughter-biased parental investment hypothesis for matriliny, which is supported by data on sex, wealth and reproductive success from two African societies, the matrilineal Chewa in Malawi and the patrilineal Gabbra in Kenya.

Holden, Clare Janaki; Mace, Ruth

2003-01-01

314

A concept for the entry, descent, and landing of high-mass payloads at Mars  

Microsoft Academic Search

The architecture concepts and aggressive science objectives for the next phases of Mars exploration will require landed masses an order of magnitude or greater than any Mars mission previously planned or flown. Additional studies have shown the requirements for missions more ambitious than the 2009 Mars Science Laboratory (?900kg payload mass) to extend beyond the capabilities of Viking-heritage entry, descent,

Ashley M. Korzun; Gregory F. Dubos; Curtis K. Iwata; Benjamin A. Stahl; John J. Quicksall

2010-01-01

315

Final STS35 Columbia descent BET products and results for LaRC OEX investigations  

Microsoft Academic Search

Final STS-35 'Columbia' descent Best Estimate Trajectory (BET) products have been developed for Langley Research Center (LaRC) Orbiter Experiments (OEX) investigations. Included are the reconstructed inertial trajectory profile; the Extended BET, which combines the inertial data and, in this instance, the National Weather Service atmospheric information obtained via Johnson Space Center; and the Aerodynamic BET. The inertial BET utilized Inertial

Kevin F. Oakes; John T. Findlay; Rachel A. Jasinski; James S. Wood

1991-01-01

316

Worst-case quadratic loss bounds for prediction using linear functions and gradient descent  

Microsoft Academic Search

Studies the performance of gradient descent (GD) when applied to the problem of online linear prediction in arbitrary inner product spaces. We prove worst-case bounds on the sum of the squared prediction errors under various assumptions concerning the amount of a priori information about the sequence to predict. The algorithms we use are variants and extensions of online GD. Whereas

Nicolo Cesa-bianchi; Philip M. Long; Manfred K. Warmuth

1996-01-01

317

Descent of the ancient Farallon slab drives localized mantle flow below the New Madrid seismic zone  

Microsoft Academic Search

The great earthquake sequence that occurred in the central Mississippi River Valley during the winter of 1811–1812 is unprecedented in the historical record of seismicity within stable continental plate interiors. We show, using viscous flow models based on high resolution seismic tomography, that the descent of the ancient Farallon slab into the deep mantle beneath central North America induces a

A. M. Forte; J. X. Mitrovica; R. Moucha; N. A. Simmons; S. P. Grand

2007-01-01

318

Cerebellar mutism associated with a midbrain cavernous malformation. Case report and review of the literature.  

PubMed

The authors report a case of cerebellar mutism arising from a hemorrhagic midbrain cavernous malformation in a 14-year-old boy. No cerebellar lesion was identified; however, edema of the dorsal midbrain was noted on postoperative magnetic resonance images. Dysarthric speech spontaneously returned and then completely resolved to normal speech. This case provides further evidence for the theory that involvement of the dentatothalamic tracts, and not a cerebellar lesion per se, is the underlying cause of "cerebellar" mutism. PMID:11883849

Wang, Marjorie C; Winston, Ken R; Breeze, Robert E

2002-03-01

319

Presynaptic Calcium Signalling in Cerebellar Mossy Fibres  

PubMed Central

Whole-cell recordings were obtained from mossy fibre terminals in adult turtles in order to characterize the basic membrane properties. Calcium imaging of presynaptic calcium signals was carried out in order to analyse calcium dynamics and presynaptic GABA B inhibition. A tetrodotoxin (TTX)-sensitive fast Na+ spike faithfully followed repetitive depolarizing pulses with little change in spike duration or amplitude, while a strong outward rectification dominated responses to long-lasting depolarizations. High-threshold calcium spikes were uncovered following addition of potassium channel blockers. Calcium imaging using Calcium-Green dextran revealed a stimulus-evoked all-or-none TTX-sensitive calcium signal in simple and complex rosettes. All compartments of a complex rosette were activated during electrical activation of the mossy fibre, while individual simple and complex rosettes along an axon appeared to be isolated from one another in terms of calcium signalling. CGP55845 application showed that GABA B receptors mediated presynaptic inhibition of the calcium signal over the entire firing frequency range of mossy fibres. A paired-pulse depression of the calcium signal lasting more than 1?s affected burst firing in mossy fibres; this paired-pulse depression was reduced by GABA B antagonists. While our results indicated that a presynaptic rosette electrophysiologically functioned as a unit, topical GABA application showed that calcium signals in the branches of complex rosettes could be modulated locally, suggesting that cerebellar glomeruli may be dynamically sub-compartmentalized due to ongoing inhibition mediated by Golgi cells. This could provide a fine-grained control of mossy fibre-granule cell information transfer and synaptic plasticity within a mossy fibre rosette.

Thomsen, Louiza B.; Jorntell, Henrik; Midtgaard, Jens

2009-01-01

320

An unusual cause of adult onset cerebellar ataxia with hypogonadism  

PubMed Central

We report an unusual case of sporadic adult onset cerebellar ataxia with hypogonadism. A 40-year-old unmarried man presented with progressive ataxia and dysarthria along with complaints of non-development of secondary sexual characteristics and erectile dysfunction. There were complaints of intermittent diarrhea. Clinical examination revealed a pan-cerebellar syndrome with features of hypoandrogenism. No eye movement abnormalities were evident. There were signs of malabsorption. Investigations confirmed the presence of auto-antibodies found in celiac disease, and a duodenal biopsy confirmed the same. Hypoandrogenism was postulated to be due to hypergonadotropic hypogonadism which has been mentioned in a few patients of celiac disease. However, the pattern seen in our patient was of a hypogonadotropic hypogonadism. This is probably secondary to an autoimmune hypophysitis seen in some patients in the absence of other clinical manifestations. Autoantibody testing should be a diagnostic necessity in any adult with a sporadic cerebellar ataxia.

Menon, Ramshekhar N.; Sanghani, Nirav; Javali, Mahendra; Jain, Neeraj; Shah, Arun B.

2009-01-01

321

Cerebellar mutism after basilar artery occlusion--case report.  

PubMed

A 30-year-old female became comatose due to embolic occlusion of the basilar artery, caused by surgical injury to the origin of the vertebral artery during removal of a neurinoma in the upper thoracic paravertebral region. The basilar artery occlusion was treated by local fibrinolysis through a microcatheter. Two weeks later she recovered her consciousness but suffered mutism. Her speech disturbance was characterized by severe ataxic dysarthria known as "cerebellar mutism" but without cranial nerve paresis. The mutism gradually improved during the following 3 months. This is case of cerebellar mutism was apparently due to ischemic stroke. Disturbance by hypoperfusion of the cerebellum and brain stem may have been involved in the pathogenesis of cerebellar mutism. PMID:9805903

Nishikawa, M; Komiyama, M; Sakamoto, H; Yasui, T; Nakajima, H

1998-09-01

322

Linguistic and cognitive deficits associated with cerebellar mutism.  

PubMed

Cerebellar mutism is a period of transient loss of speech following posterior fossa surgery, usually in children under 15 years of age. To date, cases presented in the literature have addressed primarily the motor speech aspect of the phenomenon, with little documentation relative to higher-level linguistic and cognitive functioning of these children. Recent research, however, is increasingly documenting evidence of cerebellar involvement in language and cognition. This paper describes four children, three of whom presented with a period of mutism following posterior fossa surgery, and one who did not exhibit mutism. All children, however, demonstrated a similar profile of significant high-level linguistic and cognitive deficit on formal speech-language and neuropsychological measures. Documented cases to date are reviewed and compared to these subjects. Literature documenting the role of the cerebellum in language and cognition is summarized and compared to evidence of residual deficits associated with cerebellar mutism as demonstrated by the children in this study. PMID:9689237

Vandeinse, D; Hornyak, J E

323

Reversible cerebellar ataxia with thyrotoxicosis: An autoimmune brain disease in remission due to Graves' disease  

PubMed Central

We hereby report a patient with seizure disorder who was on long term carbamazepine, admitted with features of thyrotoxicosis and cerebellar dysfunction. Anticonvulsant medications are cerebellar toxins; but in this case, reversal of cerebellar dysfunction was noted upon treatment of thyrotoxicosis with antithyroid drugs.

Prakasha, S. Rama; Suresh, G.; Prakash, P. S.; D'sa, Ivor Peter

2013-01-01

324

Reversible cerebellar ataxia with thyrotoxicosis: An autoimmune brain disease in remission due to Graves' disease.  

PubMed

We hereby report a patient with seizure disorder who was on long term carbamazepine, admitted with features of thyrotoxicosis and cerebellar dysfunction. Anticonvulsant medications are cerebellar toxins; but in this case, reversal of cerebellar dysfunction was noted upon treatment of thyrotoxicosis with antithyroid drugs. PMID:23869314

Prakasha, S Rama; Suresh, G; Prakash, P S; D'sa, Ivor Peter

2013-05-01

325

Cerebellar mutism in children: Report of six cases and potential mechanisms  

Microsoft Academic Search

Cerebellar mutism is a rare finding associated with resection of posterior fossa tumors or cerebellar hemorrhages. We reviewed the medical records of six children, aged 6 to 12 years, who developed cerebellar mutism after resection of a posterior fossa mass or as a result of posterior fossa trauma. From 1989 to 1994, 210 children underwent posterior fossa resection at our

Susan Koh; Susan Beckwitt Turkel; Tallie Z Baram

1997-01-01

326

Reduced cerebellar blood flow and oxygen metabolism in spinocerebellar degeneration: a combined PET and MRI study  

Microsoft Academic Search

Fourteen patients with spinocerebellar degeneration (SCD) were subjected to MRI and PET studies. The quantitative MRI data revealed significant cerebellar and pontine atrophy in the patients with olivopontocerebellar atrophy (OPCA), and cerebellar atrophy in the patients with late cerebellar cortical atrophy (LCCA). We failed to demonstrate significant differences in the pons between LCCA patients and normal controls. PET measurements revealed

Xiaoyan Sun; Makoto Tanaka; Susumu Kondo; Shunsaku Hirai; Tomio Ishihara

1994-01-01

327

Recurrent Cerebellar Loops Simplify Adaptive Control of Redundant and Nonlinear Motor Systems  

Microsoft Academic Search

We have described elsewhere an adaptivefilter model of cerebellar learn- ing in which the cerebellar microcircuit acts to decorrelate motor com- mands from their sensory consequences (Dean, Porrill, & Stone, 2002). Learning stability required the cerebellar microcircuit to be embedded in a recurrent loop, and this has been shown to lead to a simple and modular adaptive control architecture when

John Porrill; Paul Dean

2007-01-01

328

Modulatory Effects of Theta Burst Stimulation on Cerebellar Nonsomatic Functions  

PubMed Central

Clinical and functional imaging studies suggest that the cerebellar vermis is involved in the regulation of a range of nonsomatic functions including cardiovascular control, thirst, feeding behavior, and primal emotions. Cerebello-hypothalamic circuits have been postulated to be a potential neuroanatomical substrate underlying this modulation. We tested this putative relationship between the cerebellar vermis and nonsomatic functions by stimulating the cerebellum noninvasively via neuronavigated transcranial magnetic stimulation. In this randomized, counter-balanced, within-subject study, intermittent theta burst stimulation (TBS) was applied on three different days to the vermis and the right and left cerebellar hemispheres of 12 right-handed normal subjects with the aim of modulating activity in the targeted cerebellar structure. TBS-associated changes were investigated via cardiovascular monitoring, a series of emotionally arousing picture stimuli, subjective analog scales for primal emotions, and the Profile of Mood States test. All 36 sessions of cerebellar stimulation were tolerated well without serious adverse events. Cardiovascular monitoring pointed to a mild but significant decrease in heart rate subsequent to vermal stimulation; no changes were detected in systolic or diastolic blood pressure measurements. Subjective ratings detected a significant increase in Thirst and a trend toward increased Appetite following vermal stimulation. These observations are consistent with existing neurophysiological and neuroimaging data indicating a role for the cerebellum in the regulation of visceral responses. In conjunction with the modulatory function of the cerebellum, our results suggest a role for the vermis in somatovisceral integration likely through cerebello-hypothalamic pathways. Further research is warranted to elucidate the potential mechanisms underlying the cerebellar modulation of nonsomatic functions.

Demirtas-Tatlidede, Asli; Freitas, Catarina; Pascual-Leone, Alvaro; Schmahmann, Jeremy D.

2011-01-01

329

3D Morphometric Analysis of Human Fetal Cerebellar Development  

PubMed Central

To date, growth of the human fetal cerebellum has been estimated primarily from linear measurements from ultrasound and 2D magnetic resonance imaging (MRI). In this study, we use 3D analytical methods to develop normative growth trajectories for the cerebellum in utero. We measured cerebellar volume, linear dimensions, and local surface curvature from 3D reconstructed MRI of the human fetal brain (N = 46). We found that cerebellar volume increased approximately 7-fold from 20 to 31 gestational weeks. The better fit of the exponential curve (R2 = 0.96) compared to the linear curve (R2 = 0.92) indicated acceleration in growth. Within-subject cerebellar and cerebral volumes were highly correlated (R2 = 0.94), though the cerebellar percentage of total brain volume increased from approximately 2.4% to 3.7% (R2 = 0.63). Right and left hemispheric volumes did not significantly differ. Transcerebellar diameter, vermal height, and vermal anterior to posterior diameter increased significantly at constant rates. From the local curvature analysis, we found that expansion along the inferior and superior aspects of the hemispheres resulted in decreased convexity, which is likely due to the physical constraints of the dura surrounding the cerebellum and the adjacent brainstem. The paired decrease in convexity along the inferior vermis and increased convexity of the medial hemisphere represents development of the paravermian fissure, which becomes more visible during this period. In this 3D morphometric analysis of the human fetal cerebellum, we have shown that cerebellar growth is accelerating at a greater pace than the cerebrum and described how cerebellar growth impacts the shape of the structure.

Hamzelou, Kia S.; Rajagopalan, Vidya; Habas, Piotr A.; Kim, Kio; Barkovich, A. James; Glenn, Orit A.; Studholme, Colin

2012-01-01

330

Human tonsillar IgE biosynthesis in vitro. I. Enhancement of IgE and IgG synthesis in the presence of pokeweed mitogen by T-cell irradiation  

Microsoft Academic Search

A study of the events regulating human IgE biosynthesis in vitro was undertaken with tonsillar lymphocytes. IgG synthesis was also studied to evaluate the specificity of our observations. T-cell irradiation significantly enhanced synthesis of IgE by pokeweed mitogen (PWM)-stimulated B cells from 12 of 18 donors and IgG in all 18 donors. This enhancement was the result of de novo

K. Ohta; T. Manzara; R. J. Harbeck; C. H. Kirkpatrick

1982-01-01

331

Bilateral cerebellar dysfunctions in a unilateral meso-diencephalic lesion.  

PubMed Central

The clinical syndrome of a 65-year-old patient with a slit-shaped right-sided meso-diencephalic lesion was analysed. A cerebellar syndrome with limb-kinetic ataxia, intention tremor and hypotonicity in all extremities as well as ataxic dysarthria was found. The disruption of the two cerebello-(rubro)-thalamic pathways probably explained the signs of bilateral cerebellar dysfunction. The uncrossed ascending limb of the right, and the crossed one of the left brachium conjunctivum may have been damaged by the unilateral lesion extending between caudal midbrain and dorsal thalamus. Images

von Cramon, D

1981-01-01

332

An autopsied case of progressive supranuclear palsy presenting with cerebellar ataxia and severe cerebellar involvement.  

PubMed

A Japanese male patient presented with gait disturbance at the age of 69 years. His principal symptom was cerebellar ataxia for several years. He was initially diagnosed as having olivopontocerebellar atrophy because dysarthria and ataxia gradually developed, and head CT scan showed apparent atrophy of the cerebellum and brainstem and dilatation of the fourth ventricle. Later, he showed vertical gaze palsy, dysphagia, retrocollis, parkinsonism, axial dominant rigidity and grasp reflex, and therefore, the diagnosis was modified to progressive supranuclear palsy (PSP). Progressive atrophy of the frontotemporal lobe, cerebellum and brainstem, and dilatation of the lateral, third and fourth ventricles were evident on MRI. Gastrostomy and tracheotomy were performed 9 and 10 years after onset, respectively, and the patient died after 11 years disease duration. At autopsy the brain weighed 1000?g and showed atrophy of the frontotemporal lobe, cerebellum and brainstem. Neurofibrillary tangles, mainly globose-type revealed by Gallyas-Braak silver staining, were extensively observed in the cerebral cortex and subcortical grey matter. Numerous glial fibrillary tangles, including tuft-shaped astrocytes and coiled bodies, and extensive argyrophilic threads were also recognized, particularly in the frontal lobe, basal ganglia, cerebellar white matter, brainstem and spinal cord. The Purkinje cell layer showed severe neuron loss with Bergmann's gliosis, and the dentate nucleus showed severe neuron loss with grumose degeneration. Tau-positive/Gallyas-positive inclusions in the Purkinje cells and the glial cells of the Purkinje cell layer were observed. Pathological findings of the present patient were consistent with the diagnosis of PSP, but the olivopontocerebellar involvement, particularly in the cerebellum, was generally more severe, and the quantity of tau-positive/Gallyas-positive structures were more abundant than in typical PSP cases. The existence of a distinct, rare PSP subtype with severe olivopontocerebellar involvement, "PSP-C", which tends to be clinically misdiagnosed as spinocerebellar degeneration in the early disease stage, is noteworthy. The present case corresponded to this rare subtype of PSP. PMID:23320789

Iwasaki, Yasushi; Mori, Keiko; Ito, Masumi; Tatsumi, Shinsui; Mimuro, Maya; Yoshida, Mari

2013-01-16

333

Cerebellar mutism: report of two unusual cases and review of the literature.  

PubMed

Mutism is not a common condition following cerebellar damage. Mutism following posterior cranial fossa surgery was first reported by Rekate et al. and Yonemasu in 1985. Since then, many case reports of mutism have appeared in the English literature. Very few cases developed mutism following brain stem surgery. Although mutism has been described in patients with head injury, only one case of mutism caused by a cerebellar injury has been reported, to our knowledge. We report on two patients in which the cerebellar mutism following a radical excision of an exophytic brain stem glioma and cerebellar injury developed. We reviewed the relevant literature and discussed the mechanism of cerebellar mutism. PMID:9213058

Er?ahin, Y; Mutluer, S; Saydam, S; Barçin, E

1997-05-01

334

Tumour type and size are high risk factors for the syndrome of “cerebellar” mutism and subsequent dysarthria  

Microsoft Academic Search

OBJECTIVE“Cerebellar mutis” and subsequent dysarthria (MSD) is a documented complication of posterior fossa surgery in children. In this prospective study the following risk factors for MSD were assessed: type, size and site of the tumour; hydrocephalus at presentation and after surgery, cerebellar incision site, postoperative infection, and cerebellar swelling.METHODSIn a consecutive series of 42 children with a cerebellar tumour, speech

Coriene E Catsman-Berrevoets; Hugo R Van Dongen; Paul G H Mulder; Daniel Paz y Geuze; Philippe F Paquier; Maarten H Lequin

1999-01-01

335

Pure cerebello-olivary degeneration of Marie, Foix, and Alajouanine presenting with progressive cerebellar ataxia, cognitive decline, and chorea.  

PubMed

Parenchymatous cerebellar cortical atrophy (CCA) usually presents with a "pure" cerebellar ataxia. We describe a patient with a sporadic, late-onset progressive cerebellar ataxia plus cognitive decline and chorea who had CCA at post mortem. We discuss this unique case in the current context of classification of idiopathic cerebellar ataxia. PMID:14673899

Fox, Susan H; Nieves, Anette; Bergeron, Catherine; Lang, Anthony E

2003-12-01

336

Basal ganglia and cerebellar loops: motor and cognitive circuits  

Microsoft Academic Search

The traditional view that the basal ganglia and cerebellum are simply involved in the control of movement has been challenged in recent years. One of the pivotal reasons for this reappraisal has been new information about basal ganglia and cerebellar connections with the cerebral cortex. In essence, recent anatomical studies have revealed that these connections are organized into discrete circuits

Frank A Middleton; Peter L Strick

2000-01-01

337

Differences in cerebellar blood volume in schizophrenia and bipolar disorder  

Microsoft Academic Search

Brain morphometry has been studied extensively in schizophrenic patients, and among the cortical differences identified two consistent findings are decreased cerebellar vermal volume and increased volume of the fourth ventricle; although contradictory findings are reported as well. Recent cognitive activation studies utilizing PET, SPECT and fMRI have identified both decreased and increased activation in the cerebellum of schizophrenic patients compared

Russell T Loeber; Andrea R Sherwood; Perry F Renshaw; Bruce M Cohen; Deborah A Yurgelun-Todd

1999-01-01

338

Cortical networks of procedural learning: Evidence from cerebellar damage  

Microsoft Academic Search

The lateral cerebellum plays a critical role in procedural learning that goes beyond the strict motor control functions attributed to it. Patients with cerebellar damage show marked impairment in the acquisition of procedures, as revealed by their performance on the serial reaction time task (SRTT).Here we present the case of a patient affected by ischemic damage involving the left cerebellum

Sara Torriero; Massimiliano Oliveri; Giacomo Koch; Emanuele Lo Gerfo; Silvia Salerno; Laura Petrosini; Carlo Caltagirone

2007-01-01

339

Speech and Language Findings Associated with Paraneoplastic Cerebellar Degeneration  

ERIC Educational Resources Information Center

|Paraneoplastic cerebellar degeneration (PCD) is an autoimmune disease that can be associated with cancer of the breast, lung, and ovary. The clinical presentation of PCD commonly includes ataxia, visual disturbances, and dysarthria. The speech disturbances associated with PCD have not been well characterized, despite general acceptance that…

Paslawski, Teresa; Duffy, Joseph R.; Vernino, Steven

2005-01-01

340

Paraquat-induced apoptotic cell death in cerebellar granule cells  

Microsoft Academic Search

We examined the toxicity of paraquat, a possible environmental risk factor for neurodegenerative disorders like Parkinson's disease (PD). Paraquat is structurally similar to the neurotoxin MPP+ that can induce Parkinsonian-like features in rodents, non-human primates and human. Exposure of cerebellar granule cells to relatively low concentrations of paraquat (5 ?M) produces apoptotic cell death with a reduction in mitochondrial cytochrome

Rosa A González-Polo; Andrea Rodr??guez-Mart??n; José M Morán; Mireia Niso; Germán Soler; José M Fuentes

2004-01-01

341

Dissociation of Habit-Learning in Parkinson's and Cerebellar Disease  

Microsoft Academic Search

Damage to the medial-temporal region is known to result in declarative (explicit) memory deficits but nondeclarative (implicit) memory is largely unaffected by such lesions. Earlier studies have shown that some forms of implicit learning depend on cerebellar circuits but remain preserved following affections of the basal ganglia circuits. It is unknown which forms of implicit learning persist in patients with

K. Witt; A. Nuhsman; G. Deuschl

2002-01-01

342

Genetic background of apparently idiopathic sporadic cerebellar ataxia  

Microsoft Academic Search

Disease-causing mutations have been identified in various entities of autosomal dominant ataxia and in Friedreich's ataxia. However, no molecular pathogenic factor is known to cause idiopathic cerebellar ataxias. We investigated the CAG\\/CTG trinucleotide repeats causing spinocerebellar ataxia types 1, 2, 3, 6, 7, 8 and 12, and the GAA repeat of the frataxin gene in 124 patients apparently suffering from

Ludger Schöls; Sandra Szymanski; Sören Peters; Horst Przuntek; Jörg T. Epplen; Cornelia Hardt; Olaf Riess

2000-01-01

343

The primate cortico-cerebellar system: anatomy and function  

Microsoft Academic Search

Evidence has been accumulating that the primate cerebellum contributes not only to motor control, but also to higher 'cognitive' function. However, there is no consensus about how the cerebellum processes such information. The answer to this puzzle can be found in the nature of cerebellar connections to areas of the cerebral cortex (particularly the prefrontal cortex) and in the uniformity

Narender Ramnani

2006-01-01

344

Speech and Language Findings Associated with Paraneoplastic Cerebellar Degeneration  

ERIC Educational Resources Information Center

Paraneoplastic cerebellar degeneration (PCD) is an autoimmune disease that can be associated with cancer of the breast, lung, and ovary. The clinical presentation of PCD commonly includes ataxia, visual disturbances, and dysarthria. The speech disturbances associated with PCD have not been well characterized, despite general acceptance that…

Paslawski, Teresa; Duffy, Joseph R.; Vernino, Steven

2005-01-01

345

Neurodevelopmental Outcomes in Children with Cerebellar Malformations: A Systematic Review  

ERIC Educational Resources Information Center

|Cerebellar malformations are increasingly diagnosed in the fetal period. Consequently, their consideration requires stressful and often critical decisions from both clinicians and families. This has resulted in an emergent need to understand better the impact of these early life lesions on child development. We performed a comprehensive…

Bolduc, Marie-Eve; Limperopoulos, Catherine

2009-01-01

346

Functional Organization of Cerebellar Neuronal Systems in Frogs.  

National Technical Information Service (NTIS)

Two types of background activity (continuous and grouped) have been identified in the cerebellar cortex of frogs. Neurons with activity of b-type constitute 2% of the total number of neurons from which recordings were made. It is postulated that the role ...

F. K. Khoan

1968-01-01

347

Functional recovery of children and adolescents after cerebellar tumour resection  

Microsoft Academic Search

Summary This study examined whether lesions to the cerebellum obtained in early childhood are better compensated than lesions in middle childhood or adolescence. Since cerebel- lar lesions might affect motor as well a cognitive perform- ance, posture, upper limb and working memory function were assessed in 22 patients after resection of a cerebellar tumour (age at surgery 1-17 years, minimum

Jurgen Konczak; Beate Schoch; Albena Dimitrova; Elke Gizewski; Dagmar Timmann

2005-01-01

348

Variation in Brain Organization and Cerebellar Foliation in Chondrichthyans: Batoids  

Microsoft Academic Search

Interspecific variation in relative brain size (encephalization), the relative size of the five major brain areas (the telencephalon, diencephalon, mesencephalon, cerebellum, and medulla) and the level of cerebellar foliation was assessed in over 20 representative species of batoid (skates and rays), from eight families. Using species as independent data points and phylogenetically independent contrasts, relationships among each of the neuroanatomical

Thomas J. Lisney; Kara E. Yopak; John C. Montgomery; Shaun P. Collin

2008-01-01

349

Verb Generation in Children and Adolescents with Acute Cerebellar Lesions  

ERIC Educational Resources Information Center

|The aim of the present study was to examine verb generation in a larger group of children and adolescents with acute focal lesions of the cerebellum. Nine children and adolescents with cerebellar tumours participated. Subjects were tested a few days after tumour surgery. For comparison, a subgroup was tested also 1 or 2 days before surgery. None…

Frank, B.; Schoch, B.; Hein-Kropp, C.; Dimitrova, A.; Hovel, M.; Ziegler, W.; Gizewski, E. R.; Timmann, D.

2007-01-01

350

Normal cerebellar glutamate dehydrogenase protein in spinocerebellar degeneration  

Microsoft Academic Search

Immunochemical analyses (Western blots) of cerebellar homogenates for glutamate dehydrogenase (GDH) from patients with spinocerebellar degeneration and control subjects were conducted. Four patients with autosomal dominant Joseph disease type of spinocerebellar degeneration, one patient with autosomal dominant olivopontocerebellar degeneration and four control subjects were studied. GDH was of the same molecular weight and amount in all patients and control subjects.

R N Rosenberg; C Banner

1989-01-01

351

Treatment of cerebellar ataxia with 5-HT1A agonist.  

PubMed

Effective, pharmacologic approaches to the treatment of cerebellar ataxia are lacking or inadequate. We recently reported preliminary evidence that tandospirone citrate (tandospirone), a 5-HT1A agonist, improved cerebellar ataxia in patients with Machado-Joseph disease (MJD). In the course of that study, we found that such treatment also alleviated the pain associated with cold sensations in the legs, insomnia, anorexia, and depression, all of which are thought to be mediated through activation of the 5-HT1A receptor. In this paper, we reviewed the few published clinical trials that involved the use of 5-HT1A receptor agonists for the treatment of cerebellar ataxia, and discussed the current theories regarding their mechanism of action. Cortical cerebellar atrophy (CCA) was reported, in a double-blind study, to be amenable to treatment with tandospirone. Other types of spinocerebellar degeneration (SCD) i.e., olivopontocerebellar atrophy (OPCA) and Machado-Joseph disease (MJD) have also been reported to respond to the drug, but these have been small studies. Responsive patients exhibited only mild ataxia. The doses of 5-HT1A agonists that have been used successfully ranged from 12.5 mg/day to 60 mg/day (or 1 mg/kg), and were well tolerated by most patients. PMID:16147954

Takei, Asako; Hamada, Takeshi; Yabe, Ichiro; Sasaki, Hidenao

2005-01-01

352

Saccade velocity in idiopathic and autosomal dominant cerebellar ataxia  

Microsoft Academic Search

Slow saccades are often found in degenerative ataxia. Experimental studies have shown that horizontal saccades are generated in the paramedian pontine reticular formation and that lesions in this area produce slow saccades. Based on these findings, saccade slowing should be a frequent feature of olivopontocerebellar atrophy, a type of cerebellar degeneration with prominent involvement of the pons. To test this

K Bürk; M Fetter; M Skalej; F Laccone; G Stevanin; J Dichgans; T Klockgether

1997-01-01

353

Development of GABA innervation in the cerebral and cerebellar cortices  

Microsoft Academic Search

In many areas of the vertebrate brain, such as the cerebral and cerebellar cortices, neural circuits rely on inhibition mediated by GABA (?-aminobutyric acid) to shape the spatiotemporal patterns of electrical signalling. The richness and subtlety of inhibition are achieved by diverse classes of interneurons that are endowed with distinct physiological properties. In addition, the axons of interneurons display highly

G. Di Cristo; F. Ango; Z. J. Huang

2007-01-01

354

Encoding of movement time by populations of cerebellar Purkinje cells  

Microsoft Academic Search

One of the earliest computational principles attributed to the cerebellum was the measurement of time. This idea was originally suggested on anatomical grounds, and was taken up again to explain some of the deficits in cerebellar patients. The contribution of the cerebellum to eye movements, in contrast, has traditionally been discussed in the context of motor learning. This view has

Peter Thier; Peter W. Dicke; Roman Haas; Shabtai Barash

2000-01-01

355

Arachnodactyly, aminoaciduria, congenital cataracts, cerebellar ataxia, and delayed developmental milestones  

PubMed Central

Two male cousins are reported with arachnodactyly, selective aminoaciduria, congenital cataracts, cerebellar ataxia, and delayed developmental milestones, and a distant female relative with similar abnormalities. The syndrome is thought to be previously undescribed, though it has resemblances to Marinesco-Sjögren and Marfan's syndromes. Images

Bhaskar, P. A.; Jagannathan, K.; Valmikinathan, K.

1974-01-01

356

Is a Cerebellar Deficit the Underlying Cause of Reading Disabilities?  

ERIC Educational Resources Information Center

|This study investigated whether children with dyslexia differed in their performance on reading, phonological, rapid naming, motor, and cerebellar-related tasks and automaticity measures compared to reading age (RA)-matched and chronological age (CA)-matched control groups. Participants were 51 children attending mainstream English elementary…

Irannejad, Shahrzad; Savage, Robert

2012-01-01

357

Crossed cerebellar diaschisis after middle cerebral artery infarction  

Microsoft Academic Search

It is unclear whether crossed cerebellar diaschisis (CCD) is merely an epiphenomenon, as its clinical significance remains uncertain. We retrospectively analysed the positron emission tomographic (PET) findings in 28 patients with a chronic, stable middle cerebral artery (MCA) infarct and in 22 controls, using the steady state technique and 15O. Also, the Orgogozo scores on admission and at the time

J. De Reuck; D. Decoo; I. Lemahieu; K. Strijckmans; P. Goethals; G. Van Maele

1997-01-01

358

The myelination of the cerebellar cortex in the cat  

Microsoft Academic Search

The myelination of the cerebellar cortex of the cat was investigated in 61 cats aged from 3 hrs post partum to two and a half years. The first myelinated fibers appear at the time of birth in the central medullary ray. Before the onset of myelination, all fibers reach a critical diameter of about 1 µm. About the 14th day

W. Lange; Hochschule Aachen

1978-01-01

359

Reacquisition of classical conditioning after removal of cerebellar cortex  

Microsoft Academic Search

We trained rabbits with white noise and light conditioned stimuli and a face shock unconditioned stimulus for classical conditioning of the nictitating membrane response and then removed the ipsilateral cerebellar cortex by aspiration. Larsell's hemisphere lobule VI was completely removed in 5 rabbits; the pattern of degeneration in the inferior olive matches the projections to HVI reported in experiments with

D. G. Lavond; J. E. Steinmetz; M. H. Yokaitis; R. F. Thompson

1987-01-01

360

A way of Fuzzy Cerebellar Mode Articulation PID controller design  

Microsoft Academic Search

In this paper, an adaptive robust Fuzzy Cerebellar Model Articulation Proportional-Integral-Derivative controller for nonlinear complicated system is presented. Embedding robust control assures the stability of system, the compensated controller eliminates the noise of environment and the uncertain. Because of the chattering control signal, the optimization and redesign adaptive laws are presented. All of them are based on Lyapunov function such

Zhou Yi-min; Fan Chang-wei; Chen Jen-yang

2010-01-01

361

Spectrum of the Posterior Inferior Cerebellar Artery Territory Infarcts  

Microsoft Academic Search

Background and Purpose: The clinical, etiological and stroke mechanisms are defined well before but the detailed clinical and etiologic mechanisms regarding to all clinical spectrum of posterior inferior cerebellar artery (PICA) infarcts were not systematically studied by diffusion-weighted imaging (DWI). Methods: Seventy-four patients with PICA territory ischemic lesion proved by DWI with decreased apparent diffusion coefficient and FLAIR (fluid attenuation

Emre Kumral; Ceyla Ataç; Nilgün Yünten

2005-01-01

362

Cerebellar Damage Produces Selective Deficits in Verbal Working Memory  

ERIC Educational Resources Information Center

The cerebellum is often active in imaging studies of verbal working memory, consistent with a putative role in articulatory rehearsal. While patients with cerebellar damage occasionally exhibit a mild impairment on standard neuropsychological tests of working memory, these tests are not diagnostic for exploring these processes in detail. The…

Ravizza, Susan M.; Mccormick, Cristin A.; Schlerf, John E.; Justus, Timothy; Ivry, Richard B.; Fiez, Julie A.

2006-01-01

363

Verb Generation in Children and Adolescents with Acute Cerebellar Lesions  

ERIC Educational Resources Information Center

The aim of the present study was to examine verb generation in a larger group of children and adolescents with acute focal lesions of the cerebellum. Nine children and adolescents with cerebellar tumours participated. Subjects were tested a few days after tumour surgery. For comparison, a subgroup was tested also 1 or 2 days before surgery. None…

Frank, B.; Schoch, B.; Hein-Kropp, C.; Dimitrova, A.; Hovel, M.; Ziegler, W.; Gizewski, E. R.; Timmann, D.

2007-01-01

364

Modeling cerebellar granular layer excitability and combinatorial computation with spikes  

Microsoft Academic Search

The cerebellum input stage has been known to perform combinatorial operations [1] [3] on input signals. In this paper, we developed a model to study information transmission and signal recoding in the cerebellar granular layer and to test observations like center-surround organization and time-window hypothesis [1] [2]. We also developed simple neuron models for abstracting timing phenomena in large networks.

C. Medini; S. Subramaniyam; B. Nair; S. Diwakar

2010-01-01

365

Caytaxin Deficiency Disrupts Signaling Pathways in Cerebellar Cortex  

PubMed Central

The genetically dystonic (dt) rat, an autosomal recessive model of generalized dystonia, harbors an insertional mutation in Atcay. As a result, dt rats are deficient in Atcay transcript and the neuronally-restricted protein caytaxin. Previous electrophysiological and biochemical studies have defined olivocerebellar pathways, particularly the climbing fiber projection to Purkinje cells, as a site of significant functional abnormality in dt rats. In normal rats, Atcay transcript is abundantly expressed in the granular and Purkinje cell layers of cerebellar cortex. To better understand the consequences of caytaxin deficiency in cerebellar cortex, differential gene expression was examined in dt rats and their normal littermates. Data from oligonucleotide microarrays and quantitative real-time RT-PCR (QRT-PCR) identified phosphatidylinositol signaling pathways, calcium homeostasis, and extracellular matrix interactions as domains of cellular dysfunction in dt rats. In dt rats, genes encoding the corticotropin-releasing hormone receptor 1 (CRH-R1, Crhr1) and calcium-transporting plasma membrane ATPase 4 (PMCA4, Atp2b4) showed the greatest up-regulation with QRT-PCR. Immunocytochemical experiments demonstrated that CRH-R1, CRH, and PMCA4 were up-regulated in cerebellar cortex of mutant rats. Along with previous electrophysiological and pharmacological studies, our data indicate that caytaxin plays a critical role in the molecular response of Purkinje cells to climbing fiber input. Caytaxin may also contribute to maturational events in cerebellar cortex.

Xiao, Jianfeng; Gong, Suzhen; LeDoux, Mark S.

2007-01-01

366

Concomitant tubercular and fungal cerebellar abscess in an immunocompromised girl.  

PubMed

Concomitant tubercular and fungal cerebellar abscess is rare and we report the first concomitant recurrent multi-lobulated tubercular and fungal cerebellar abscess in an immunocompromised girl with Histiocytosis-X. She presented with cerebellar abscess history diagnosed during the ongoing treatment for tuberculous meningitis. The abscess was drained. Upon the detection of cerebellar abscess recurrence and pulmonary infection, she was referred to our clinic five weeks after the first surgical intervention. Patient was conscious, co-operating but confused. She had severe cachexia, stiff neck and fever. Fundus examination showed bilateral papilledema. Cranial MR images revealed multiple lobulated lesions. Suboccipital craniectomy was performed and abscess was evacuated in toto. Lesion was multi-lobulated. Thick, yellow-gray purulent material was drained. Histopathological examinations yielded Langhans giant cells,budding and branching fungal structures. Fungal infection was identified. We emphasize that posterior decompression and total resection should be considered first in the management of lesions with mass effect in the posterior fossa. Also the presence of concomitant fatal fungal abscess highlights that although the clinic and former diagnoses of the patient may direct the clinician to a certain pathogen, unusual resistant organisms should not be. PMID:23344873

Simsek, Hakan; Kutlay, Murat; Colak, Ahmet; Haholu, Aptullah; Kaya, Hatice; Ozyurt, Mustafa; Demircan, Mehmet Nusret

2013-01-01

367

Performance Evaluation of a Lower Limb Exoskeleton for Stair Ascent and Descent with Paraplegia*  

PubMed Central

This paper describes the application of a powered lower limb exoskeleton to aid paraplegic individuals in stair ascent and descent. A brief description of the exoskeleton hardware is provided along with an explanation of the control methodology implemented to allow stair ascent and descent. Tests were performed with a paraplegic individual (T10 complete injury level) and data is presented from multiple trials, including the hip and knee joint torque and power required to perform this functionality. Joint torque and power requirements are summarized, including peak hip and knee joint torque requirements of 0.75 Nm/kg and 0.87 Nm/kg, respectively, and peak hip and knee joint power requirements of approximately 0.65 W/kg and 0.85 W/kg, respectively.

Farris, Ryan J.; Quintero, Hugo A.; Goldfarb, Michael

2013-01-01

368

The probabilistic determination of identity-by-descent sharing for pairs of relatives from pedigrees.  

PubMed Central

Methods for detecting genetic linkage are more powerful when they fully use all of the data collected from pedigrees. We first discuss a method for obtaining the probability that a pedigree member has a given genotype, conditional on the phenotypes of his relatives. We then develop a rapid method to obtain the conditional probabilities of identity-by-descent sharing of marker alleles for all related pairs of individuals from extended pedigrees. The method assumes that the individuals are noninbred and that the relationship between genotype and phenotype is known for the marker locus studied. The probabilities of identity-by-descent sharing among relative pairs, conditional on marker phenotype information, can then be used in any of the model free tests for linkage between a trait locus and a marker locus.

Amos, C I; Dawson, D V; Elston, R C

1990-01-01

369

Estimation of heritability from limited family data using genome-wide identity-by-descent sharing  

PubMed Central

Background In classical pedigree-based analysis, additive genetic variance is estimated from between-family variation, which requires the existence of larger phenotyped and pedigreed populations involving numerous families (parents). However, estimation is often complicated by confounding of genetic and environmental family effects, with the latter typically occurring among full-sibs. For this reason, genetic variance is often inferred based on covariance among more distant relatives, which reduces the power of the analysis. This simulation study shows that genome-wide identity-by-descent sharing among close relatives can be used to quantify additive genetic variance solely from within-family variation using data on extremely small family samples. Methods Identity-by-descent relationships among full-sibs were simulated assuming a genome size similar to that of humans (effective number of loci ~80). Genetic variance was estimated from phenotypic data assuming that genomic identity-by-descent relationships could be accurately re-created using information from genome-wide markers. The results were compared with standard pedigree-based genetic analysis. Results For a polygenic trait and a given number of phenotypes, the most accurate estimates of genetic variance were based on data from a single large full-sib family only. Compared with classical pedigree-based analysis, the proposed method is more robust to selection among parents and for confounding of environmental and genetic effects. Furthermore, in some cases, satisfactory results can be achieved even with less ideal data structures, i.e., for selectively genotyped data and for traits for which the genetic variance is largely under the control of a few major genes. Conclusions Estimation of genetic variance using genomic identity-by-descent relationships is especially useful for studies aiming at estimating additive genetic variance of highly fecund species, using data from small populations with limited pedigree information and/or few available parents, i.e., parents originating from non-pedigreed or even wild populations.

2012-01-01

370

Parents' science talk to their children in Mexican-descent families residing in the USA  

Microsoft Academic Search

Everyday parent—child conversations may support children's scientific understanding. The types and frequency of parent—child science talk may vary with the cultural and schooling background of the participants, and yet most research in the USA focuses on highly schooled European-American families. This study investigated 40 Mexican-descent parents' science talk with their children (mean age = 5 years 7 months, range =

Harriet R. Tenenbaum; Maureen A. Callanan

2008-01-01

371

Multi-institutional prostate cancer study of genetic susceptibility in populations of African descent.  

PubMed

Prostate cancer disparities have been reported in men of African descent who show the highest incidence, mortality, compared with other ethnic groups. Few studies have explored the genetic and environmental factors for prostate cancer in men of African ancestry. The glutathione-S-transferases family conjugates carcinogens before their excretion and is expressed in prostate tissue. This study addressed the role of GSTM1 and GSTT1 deletions on prostate cancer risk in populations of African descent. This multi-institutional case-control study gathered data from the Genetic Susceptibility to Environmental Carcinogens (GSEC) database, the African-Caribbean Cancer Consortium (AC3) and Men of African Descent and Carcinoma of the Prostate Consortium (MADCaP). The analysis included 10 studies (1715 cases and 2363 controls), five in African-Americans, three in African-Caribbean and two in African men. Both the GSTM1 and the GSTT1 deletions showed significant inverse associations with prostate cancer [odds ratio (OR): 0.90, 95% confidence interval (CI) 0.83-0.97 and OR 0.88, 95% CI: 0.82-0.96, respectively]. The association was restricted to Caribbean and African populations. A significant positive association was observed between GSTM1 deletion and prostate cancer in smokers in African-American studies (OR: 1.28, 95% CI: 1.01-1.56), whereas a reduced risk was observed in never-smokers (OR: 0.66, 95% CI: 0.46-0.95). The risk of prostate cancer increased across quartiles of pack-years among subjects carrying the deletion of GSTM1 but not among subjects carrying a functional GSTM1. Gene-environment interaction between smoking and GSTM1 may be involved in the etiology of prostate cancer in populations of African descent. PMID:21705483

Taioli, Emanuela; Flores-Obando, Rafael E; Agalliu, Ilir; Blanchet, Pascal; Bunker, Clareann H; Ferrell, Robert E; Jackson, Maria; Kidd, La Creis R; Kolb, Suzanne; Lavender, Nicol A; McFarlane-Anderson, Norma; Morrison, Seian S; Multigner, Luc; Ostrande, Elaine A; Park, Jong Y; Patrick, Alan L; Rebbeck, Timothy R; Romana, Marc; Stanford, Janet L; Ukoli, Flora; Vancleave, Tiva T; Zeigler-Johnson, Charnita M; Mutetwa, Batsirai; Ragin, Camille

2011-06-24

372

Symmetric Functions and Generating Functions for Descents and Major Indices in Compositions  

Microsoft Academic Search

In [18], Mendes and Remmel showed how Gessel’s generating function for the distributions of the number of descents, the major\\u000a index, and the number of inversions of permutations in the symmetric group could be derived by applying a ring homomorphism\\u000a defined on the ring of symmetric functions to a simple symmetric function identity. We show how similar methods may be

Evan Fuller; Jeffrey Remmel

2010-01-01

373

Multi-institutional prostate cancer study of genetic susceptibility in populations of African descent  

PubMed Central

Prostate cancer disparities have been reported in men of African descent who show the highest incidence, mortality, compared with other ethnic groups. Few studies have explored the genetic and environmental factors for prostate cancer in men of African ancestry. The glutathione-S-transferases family conjugates carcinogens before their excretion and is expressed in prostate tissue. This study addressed the role of GSTM1 and GSTT1 deletions on prostate cancer risk in populations of African descent. This multi-institutional case–control study gathered data from the Genetic Susceptibility to Environmental Carcinogens (GSEC) database, the African-Caribbean Cancer Consortium (AC3) and Men of African Descent and Carcinoma of the Prostate Consortium (MADCaP). The analysis included 10 studies (1715 cases and 2363 controls), five in African-Americans, three in African-Caribbean and two in African men. Both the GSTM1 and the GSTT1 deletions showed significant inverse associations with prostate cancer [odds ratio (OR): 0.90, 95% confidence interval (CI) 0.83–0.97 and OR 0.88, 95% CI: 0.82–0.96, respectively]. The association was restricted to Caribbean and African populations. A significant positive association was observed between GSTM1 deletion and prostate cancer in smokers in African-American studies (OR: 1.28, 95% CI: 1.01–1.56), whereas a reduced risk was observed in never-smokers (OR: 0.66, 95% CI: 0.46–0.95). The risk of prostate cancer increased across quartiles of pack-years among subjects carrying the deletion of GSTM1 but not among subjects carrying a functional GSTM1. Gene–environment interaction between smoking and GSTM1 may be involved in the etiology of prostate cancer in populations of African descent.

Taioli, Emanuela; Flores-Obando, Rafael E.; Agalliu, Ilir; Blanchet, Pascal; Bunker, Clareann H.; Ferrell, Robert E.; Jackson, Maria; Kidd, La Creis R.; Kolb, Suzanne; Lavender, Nicol A.; McFarlane-Anderson, Norma; Morrison, Seian S.; Multigner, Luc; Ostrande, Elaine A.; Park, Jong Y.; Patrick, Alan L.; Rebbeck, Timothy R.; Romana, Marc; Stanford, Janet L.; Ukoli, Flora; VanCleave, Tiva T.; Zeigler-Johnson, Charnita M.; Mutetwa, Batsirai; Ragin, Camille

2011-01-01

374

The behavior of epididymis, processus vaginalis and testicular descent in cryptorchid boys treated with buserelin  

Microsoft Academic Search

This randomized double-blind placebo-controlled study was initiated to analyze the behavior of epididymis, processus vaginalis and testicular descent in cryptorchid boys treated with a low dose (20 ?g) of a luteinizing hormone-releasing hormone analogue (Buserelin), administered daily, as a nasal spray, for a short period (28 days). Fifty-nine true cryptorchid boys were randomly assigned to 3 groups: buserelin, treatment [22],

Domingos TG Bica; Faruk Hadziselimovic

1993-01-01

375

On the use of a range trigger for the Mars Science Laboratory Entry, Descent, and Landing  

Microsoft Academic Search

In 2012, during the Entry, Descent, and Landing (EDL) of the Mars Science Laboratory (MSL) entry vehi- cle, a 21.5 m Viking-heritage, Disk-Gap-Band, supersonic parachute will be deployed at approximately Mach 2. The baseline algorithm for commanding this parachute deploy- ment is a navigated planet-relative velocity trigger. This pa- per compares the performance of an alternative range-to-go trigger (sometimes referred

2011-01-01

376

Clogging of Joule-Thomson Devices in Liquid Hydrogen-Lunar Lander Descent Stage Operating Regime  

Microsoft Academic Search

Joule-Thomson (J-T) devices have been identified as critical components for future space exploration missions. The NASA Constellation Program lunar architecture considers LOX\\/LH2 propulsion for the lunar lander descent stage main engine an enabling technology, ensuring the cryogenic propellants are available at the correct conditions for engine operation. This cryogenic storage system may utilize a Thermodynamic Vent System (TVS) that includes

J. M. Jurns

2010-01-01

377

CLOGGING OF JOULE-THOMSON DEVICES IN LIQUID HYDROGEN—LUNAR LANDER DESCENT STAGE OPERATING REGIME  

Microsoft Academic Search

Joule-Thomson (J-T) devices have been identified as critical components for future space exploration missions. The NASA Constellation Program lunar architecture considers LOX\\/LH2 propulsion for the lunar lander descent stage main engine an enabling technology, ensuring the cryogenic propellants are available at the correct conditions for engine operation. This cryogenic storage system may utilize a Thermodynamic Vent System (TVS) that includes

J. M. Jurns

2010-01-01

378

A comparison of androgenetic doubled-haploid, and single seed descent lines in Triticale  

Microsoft Academic Search

Sixty single seed descent (SSD) lines and about 25 anther-derived doubled-haploid (DH) lines were obtained from two triticale crosses. The frequency distributions of 10 quantitative agronomic traits were compared using parametric and non-parametric tests. A multivariate discriminant analysis was subsequently carried out. Gliadin patterns obtained from each line by polyacrylamide gel electrophoresis were used to calculate intra- and inter-population diversities

G. Charmet; G. Branlard

1985-01-01

379

A Study of Matrilineal Descent from the Perspective of the Tlingit NexA'di Eagles  

Microsoft Academic Search

The Athapaskans of the boreal forest of northwestern Canada and Alaska and the Indians of the northern Northwest Coast shared a similar social organization. It was based on the division of a group into moieties and\\/or phratries, tracing matrilineal descent, practicing exogamy, matrilocality, and sharing resources with other affiliate groups. The Sanyaqoan NexA'di Eagle clan was singular among the Tlingit

CHRIS RABICH CAMPBELL

380

Demography of Exercise among Californians of Korean Descent: A Cross-Sectional Telephone Survey  

Microsoft Academic Search

This study describes aerobic exercise and walking for exercise behaviors among the Korean American population, a rapidly growing\\u000a minority. Data for this study were drawn from a representative survey of Californians of Korean descent (N = 2,830) conducted by telephone; 86% of eligible participants completed interviews in either Korean or English. Sample characteristics\\u000a closely approximated those for Koreans in the 2000 United

C. Richard Hofstetter; Veronica Irvin; Katy Schmitz; Melbourne F. Hovell; Jeanne Nichols; Hye Ryun Kim; Richard Ledet; Joy Zakarian; Hee-Young Paik; Jooeun Lee

2008-01-01

381

Functional recovery of children and adolescents after cerebellar tumour resection.  

PubMed

This study examined whether lesions to the cerebellum obtained in early childhood are better compensated than lesions in middle childhood or adolescence. Since cerebellar lesions might affect motor as well a cognitive performance, posture, upper limb and working memory function were assessed in 22 patients after resection of a cerebellar tumour (age at surgery 1-17 years, minimum 3 years post-surgery). Working memory was only impaired in those patients who had received chemo- or radiation therapy. Postural sway was enhanced in 64% of the patients during dynamic posturography conditions, which relied heavily on vestibular input for equilibrium control. Upper limb function was generally less impaired, but 54% of the patients revealed prolonged deceleration times in an arm pointing task, which probably does not reflect a genuine cerebellar deficit but rather the patients' adopted strategy to avoid overshooting. Age at surgery, time since surgery or lesion volume were poor predictors of motor or cognitive recovery. Brain imaging analysis revealed that lesions of all eight patients with abnormal posture who did not receive chemo- and/or radiation therapy included the fastigial and interposed nuclei (NF and NI). In patients with normal posture, NI and NF were spared. In 11 out of 12 patients with abnormal deceleration time, the region with the highest overlap included the NI and NF and dorsomedial portions of the dentate nuclei in 10 out of 12 patients. We conclude that cerebellar damage inflicted at a young age is not necessarily better compensated. The lesion site is critical for motor recovery, and lesions affecting the deep cerebellar nuclei are not fully compensated at any developmental age in humans. PMID:15659424

Konczak, Jürgen; Schoch, Beate; Dimitrova, Albena; Gizewski, Elke; Timmann, Dagmar

2005-01-19

382

Adaptive filters and internal models: Multilevel description of cerebellar function.  

PubMed

Cerebellar function is increasingly discussed in terms of engineering schemes for motor control and signal processing that involve internal models. To address the relation between the cerebellum and internal models, we adopt the chip metaphor that has been used to represent the combination of a homogeneous cerebellar cortical microcircuit with individual microzones having unique external connections. This metaphor indicates that identifying the function of a particular cerebellar chip requires knowledge of both the general microcircuit algorithm and the chip's individual connections. Here we use a popular candidate algorithm as embodied in the adaptive filter, which learns to decorrelate its inputs from a reference ('teaching', 'error') signal. This algorithm is computationally powerful enough to be used in a very wide variety of engineering applications. However, the crucial issue is whether the external connectivity required by such applications can be implemented biologically. We argue that some applications appear to be in principle biologically implausible: these include the Smith predictor and Kalman filter (for state estimation), and the feedback-error-learning scheme for adaptive inverse control. However, even for plausible schemes, such as forward models for noise cancellation and novelty-detection, and the recurrent architecture for adaptive inverse control, there is unlikely to be a simple mapping between microzone function and internal model structure. This initial analysis suggests that cerebellar involvement in particular behaviours is therefore unlikely to have a neat classification into categories such as 'forward model'. It is more likely that cerebellar microzones learn a task-specific adaptive-filter operation which combines a number of signal-processing roles. PMID:23391782

Porrill, John; Dean, Paul; Anderson, Sean R

2012-12-28

383

Machado-Joseph disease in pedigrees of Azorean descent is linked to chromosome 14  

SciTech Connect

A locus for Machado-Joseph disease (MJD) has recently been mapped to a 30-cM region of chromosome 14q in five pedigrees of Japanese descent. MJD is a clinically pleomorphic neurodegenerative disease that was originally described in subjects of Azorean descent. In light of the nonallelic heterogeneity in other inherited spinocerebellar ataxias, the authors were interested to determine if the MJD phenotype in Japanese and Azorean pedigrees arose from mutations at the same locus. They provide evidence that MJD in five pedigrees of Azorean descent is also linked to chromosome 14q in an 18-cM region between the markers D14S67 and AACT (multipoint lod score +7.00 near D14S81). They also report molecular evidence for homozygosity at the MJD locus in an MJD-affected subject with severe, early-onset symptoms. These observations confirm the initial report of linkage of MJD to chromosome 14; suggest that MJD in Japanese and Azorean subjects may represent allelic or identical mutations at the same locus; and provide one possible explanation (MJD gene dosage) for the observed phenotypic heterogeneity in this disease. 22 refs., 3 figs., 1 tab.

George-Hyslop, P. St.; McLachlan, D.R.C.; Lang, A.E.; Wherrett, J.R.; Rogaeva, E.; Tsuda, T.; Rogaev, E.I.; Liang, Y.; Huterer, J.; Kennedy, J. (Univ. of Toronto (Canada)) (and others)

1994-07-01

384

Review of studies on metabolic genes and cancer in populations of African descent  

PubMed Central

Genetic polymorphisms described for a number of enzymes involved in the metabolism of tobacco carcinogens and alcohol have been linked to increase cancer risk. Racial disparities in cancer between Whites and populations of African descent are well documented. In addition to differences in access to health care, both environment and genetic factors and their interaction may contribute to the increased cancer risk in minority populations. We reviewed the literature to identify case-control studies that included subjects of African descent. Meta analyses investigating the association of genetic polymorphisms in tobacco metabolic genes and cancer were performed. While several genes and cancers have been studied, only one or two studies per gene for each cancer site have been published, with the exception of breast (CYP1A1 and CYP1B1), lung (GSTM1, CYP1A1, and NQO1) and prostate (CYP3A4 A293G and CYP17). Marginal statistically significant associations were observed for CYP3A4 A293G and CYP17 5'UTR polymorphisms and prostate cancer. Our findings support the need for additional genetic association studies of breast, prostate and lung cancers that include a larger number of minority participants. Since incidence and mortality rates for these cancers rank highest among populations of African descent concentrated research in these areas are warranted.

Ragin, Camille C.; Langevin, Scott; Rubin, Scott; Taioli, Emanuela

2010-01-01

385

Techniques for avoiding local minima in gradient-descent-based ID algorithms  

NASA Astrophysics Data System (ADS)

One nonlinear adaptive approach to generating target recognition algorithms, the distributed connectionist approach, is also referred to as a neural network. These algorithms frequently employ a gradient descent technique, such as the back propagation learning algorithm, to find a mapping that separates the n dimensional feature space into m recognizable classes. Gradient descent techniques are known to be limited by a characteristic referred to as the `local minima' problem. During the search for an optimum solution or global minima, these techniques can encounter local minima from which they cannot escape due to the `steepest descent' nature of the approach. However, several training techniques used to speed up training or to otherwise optimize these adaptive learning algorithms have side effects which can obviate this local minima problem. We will define a local minima problem with respect to the 1D target ID problem. Appropriate terminology and an error space relevant to the 1D range profile problem will be presented. Four techniques, dynamic architecture definition, weight pruning, adaptive learning rate selection and dynamic training set generation used to optimize training for the multilayer perceptron will be summarized. An analytical explanation of a common underlying mechanism which allows escape from local minima and is shared by these techniques is presented. Some additional advantages are provided by one of the four techniques, the dynamic training set technique. Evidence of these advantages, consistently high quality results, the automatic identification of anomalous signatures in the data base and simple implementation, will be presented.

Brierton, Joan L.

1997-06-01

386

The relief formed by the descent phenomenon in the north-east part of Kosova.  

PubMed

In the diverse relief of north-east part of Kosova a relatively wide range occupies the relief modelled by the descent phenomenon, which is conditioned by morph-structural and climatic factors quite suitable for their development. The morphogenesis activity of descent phenomenon is conditioned by the types of rocks, tectonic process of this region and climatic conditions. These factors condition horizontal and vertical relief fragmentation, slope, especially in Gollaku mountains and in SE part of Kopaonik mountain. Along the tectonic descents, the steepness is detaching and the detaching lines consisting of magmatic rocks show overthrows, demolitions and stony torrents, but the Teri gene composition formations are modelled by sliding and muddy torrents, depending upon the presence of clayey and alevrolite belts on these Teri gene ones. The impact of factors and conditions on the relief of this part, the phenomena like demolitions, overthrows, sliding, muddy torrents, stony torrents, etc, operate here, which play an important morphological role in the modelling of relief. PMID:23424844

Bulliqi, Shpejtim; Isufi, Florim; Ramadani, Ibrahim; Gashi, Gani

2012-04-01

387

A Tribute to Italian Physiologists of Jewish Descent Evicted During the Persecution Ordered by the Fascist Regime in 1938  

NSDL National Science Digital Library

The present report commemorates the persecution of five renown Italian physiologists of Jewish descent that lost their chairs in medical schools because of the anti-semitic policies of the fascist regime.

Ermanno Manni (Catholic University Institute of Human Physiology, School of Medicine)

2007-06-01

388

Characteristic changes of cerebellar proteins associated with cerebellar hypoplasia in jaundiced Gunn rats and the prevention of these by phototherapy  

Microsoft Academic Search

Summary In the cerebellar particulate fractions from Gunn rat homozygotes 3 protein bands with apparent mol.wts of 250,000, 50,000 and 33,000 in SDS-polyacrylamide gel disc electrophoresis underwent major changes, and phototherapy of the newborns could effectively prevent the changes.

S. Kashiwamata; S. Aono; R. K. Semba

1980-01-01

389

Comparative morphology of the hyolaryngeal complex in anthropoids: two steps in the evolution of the descent of the larynx  

Microsoft Academic Search

.   The descent of the larynx is a key phenomenon not only in postnatal development, but also in the evolution of human speech.\\u000a The positional change of the larynx is affected by the descent of the hyoid bone in relation to the mandible and cranial base,\\u000a and that of the laryngeal framework in relation to the hyoid bone. The phylogeny

Takeshi Nishimura

2003-01-01

390

Development of Cerebellar Neurons and Glias Revealed by in Utero Electroporation: Golgi-Like Labeling of Cerebellar Neurons and Glias  

PubMed Central

Cerebellar cortical functions rely on precisely arranged cytoarchitectures composed of several distinct types of neurons and glias. Studies have indicated that cerebellar excitatory and inhibitory neurons have distinct spatial origins, the upper rhombic lip (uRL) and ventricular zone (VZ), respectively, and that different types of neurons have different birthdates. However, the spatiotemporal relationship between uRL/VZ progenitors and their final phenotype remains poorly understood due to technical limitations. To address this issue, we performed in utero electroporation (IUE) of fluorescent protein plasmids using mouse embryos to label uRL/VZ progenitors at specific developmental stages, and observed labeled cells at maturity. To overcome any potential dilution of the plasmids caused by progenitor division, we also utilized constructs that enable permanent labeling of cells. Cerebellar neurons and glias were labeled in a Golgi-like manner enabling ready identification of labeled cells. Five types of cerebellar neurons, namely Purkinje, Golgi, Lugaro and unipolar brush cells, large-diameter deep nuclei (DN) neurons, and DN astrocytes were labeled by conventional plasmids, whereas plasmids that enable permanent labeling additionally labeled stellate, basket, and granule cells as well as three types of glias. IUE allows us to label uRL/VZ progenitors at different developmental stages. We found that the five types of neurons and DN astrocytes were labeled in an IUE stage-dependent manner, while stellate, basket, granule cells and three types of glias were labeled regardless of the IUE stage. Thus, the results indicate the IUE is an efficient method to track the development of cerebellar cells from uRL/VZ progenitors facing the ventricular lumen. They also indicate that while the generation of the five types of neurons by uRL/VZ progenitors is regulated in a time-dependent manner, the progenitor pool retains multipotency throughout embryonic development.

Kita, Yoshiaki; Kawakami, Koichi; Takahashi, Yoshiko; Murakami, Fujio

2013-01-01

391

Medial cerebellar nuclear projections and activity patterns link cerebellar output to orofacial and respiratory behavior  

PubMed Central

There is ample evidence that the cerebellum plays an important role in coordinating both respiratory and orofacial movements. However, the pathway by which the cerebellum engages brainstem substrates underlying these movements is not well understood. We used tract-tracing techniques in mice to show that neurons in the medial deep cerebellar nucleus (mDCN) project directly to these putative substrates. Injection of an anterograde tracer into the mDCN produced terminal labeling in the ventromedial medullary reticular formation, which was stronger on the contralateral side. Correspondingly, injection of retrograde tracers into these same areas resulted in robust neuronal cell labeling in the contralateral mDCN. Moreover, injection of two retrograde tracers at different rostral–caudal brainstem levels resulted in a subset of double-labeled cells, indicating that single mDCN neurons collateralize to multiple substrates. Using an awake and behaving recording preparation, we show that spiking activity in mDCN neurons is correlated with respiratory and orofacial behaviors, including whisking and fluid licking. Almost half of the recorded neurons showed activity correlated with more than one behavior, suggesting that these neurons may in fact modulate multiple brainstem substrates. Collectively, these results describe a potential pathway through which the cerebellum could modulate and coordinate respiratory and orofacial behaviors.

Lu, Lianyi; Cao, Ying; Tokita, Kenichi; Heck, Detlef H.; Jr., John D. Boughter

2013-01-01

392

In and out of the loop: external and internal modulation of the olivo-cerebellar loop  

PubMed Central

Cerebellar anatomy is known for its crystal like structure, where neurons and connections are precisely and repeatedly organized with minor variations across the Cerebellar Cortex. The olivo-cerebellar loop, denoting the connections between the Cerebellar cortex, Inferior Olive and Cerebellar Nuclei (CN), is also modularly organized to form what is known as the cerebellar module. In contrast to the relatively organized and static anatomy, the cerebellum is innervated by a wide variety of neuromodulator carrying axons that are heterogeneously distributed along the olivo-cerebellar loop, providing heterogeneity to the static structure. In this manuscript we review modulatory processes in the olivo-cerebellar loop. We start by discussing the relationship between neuromodulators and the animal behavioral states. This is followed with an overview of the cerebellar neuromodulatory signals and a short discussion of why and when the cerebellar activity should be modulated. We then devote a section for three types of neurons where we briefly review its properties and propose possible neuromodulation scenarios.

Libster, Avraham M.; Yarom, Yosef

2013-01-01

393

Speech and language findings associated with paraneoplastic cerebellar degeneration.  

PubMed

Paraneoplastic cerebellar degeneration (PCD) is an autoimmune disease that can be associated with cancer of the breast, lung, and ovary. The clinical presentation of PCD commonly includes ataxia, visual disturbances, and dysarthria. The speech disturbances associated with PCD have not been well characterized, despite general acceptance that dysarthria is often part of the initial presentation. A retrospective study was conducted of the speech, language, and swallowing concerns of patients with PCD evaluated at the Mayo Clinic in Rochester, MN, between 1990 and 2001. Prospective speech and language assessments were then conducted with 5 patients who had PCD. While ataxic dysarthria was the most common speech diagnosis, a spastic component was recognized frequently enough to suggest that the subacute (days to weeks) emergence and progression of an ataxic or mixed ataxic-spastic dysarthria in the setting of a more diffuse cerebellar ataxia should raise suspicions about PCD and justify further investigation of a possible immune-related etiology. PMID:16229671

Paslawski, Teresa; Duffy, Joseph R; Vernino, Steven

2005-08-01

394

Cerebellar haematomas caused by angiomas in children1  

PubMed Central

Spontaneous cerebellar haematomas in previously well children are most often caused by haemorrhage from small angiomas. Eight such cases in children 12 years of age or younger have been reported previously. Their clinical course was usually not as acute as the course most commonly seen in adults, and four of the children survived after evacuation of the haematoma. Two additional cases are presented. Both children were admitted in a comatose state, but survived after surgical intervention. Cerebellar haematomas in children seem to have a better prognosis than in adults and should be considered in the evaluation of children with subarachnoid haemorrhage or the rapid onset of coma. Even if admitted in extremis, recovery is possible after prompt diagnosis and surgical evacuation of the haematoma.

Erenberg, G.; Rubin, R.; Shulman, K.

1972-01-01

395

Cerebellar histogenesis in rats exposed to 2450-MHz microwave radiation  

SciTech Connect

Pregnant rats were either exposed or sham exposed from day 13 of gestation until birth to 2450-MHz linearly polarized microwaves at 10 mW/sq cm. A third matching group served as cage control. After birth, the pups were kept with their mothers for 21 days without any treatment, and at age 21 their brains were prepared for histological analysis. There was a statistically significant difference in the cerebellar area among the three exposure groups. The differences was seen only in the females and not in the males. Purkinje cell density was not significantly different (P>0.05) among the three exposure groups. However, Purkinje cell density in the females was highest in the microwave exposed rats and lowest in the cage controls. The differences in the cerebellar area among the three groups may not be attributed to microwave exposure but to some unidentifiable factor which differentiated the cage controls from both exposure groups.

Albert, E.N.

1988-08-01

396

Inflammatory myofibroblastic tumor of the cerebellar hemisphere--case report.  

PubMed

A 60-year-old man presented with a rare cerebellar inflammatory myofibroblastic tumor (IMT) manifesting as gait disturbance and dysarthria. Brain magnetic resonance imaging demonstrated an intra-axial round-shaped isointense mass homogeneously enhanced with gadolinium in the right cerebellar hemisphere, as well as perifocal edema extending to the brain stem and right thalamus. The tumor was elastic hard and was resected en bloc with a clear margin. Histological examination revealed IMT with spindle cells and collagen, but negative for anaplastic lymphoma kinase expression. IMT most commonly affects the lung, but may involve many other parts of the body. There is some debate regarding the disease entity of IMT in the central nervous system (IMT-CNS) because of its rarity and high frequency of recurrence. IMT-CNS is an important differential diagnosis among tumor-like intracranial lesions and total resection is required. PMID:21273753

Kato, Koichi; Moteki, Yosuke; Nakagawa, Masanori; Kadoyama, Shigeru; Ujiie, Hiroshi

2011-01-01

397

Cerebellar LTD and Pattern Recognition by Purkinje Cells  

PubMed Central

Summary Many theories of cerebellar function assume that long-term depression (LTD) of parallel fiber (PF) synapses enables Purkinje cells to learn to recognize PF activity patterns. We have studied the LTD-based recognition of PF patterns in a biophysically realistic Purkinje-cell model. With simple-spike firing as observed in vivo, the presentation of a pattern resulted in a burst of spikes followed by a pause. Surprisingly, the best criterion to distinguish learned patterns was the duration of this pause. Moreover, our simulations predicted that learned patterns elicited shorter pauses, thus increasing Purkinje-cell output. We tested this prediction in Purkinje-cell recordings both in vitro and in vivo. In vitro, we found a shortening of pauses when decreasing the number of active PFs or after inducing LTD. In vivo, we observed longer pauses in LTD-deficient mice. Our results suggest a novel form of neural coding in the cerebellar cortex.

Steuber, Volker; Mittmann, Wolfgang; Hoebeek, Freek E.; Silver, R. Angus; De Zeeuw, Chris I.; Hausser, Michael; De Schutter, Erik

2007-01-01

398

Acetylcholine sensitivity of cerebellar neurones in the cat  

PubMed Central

1. Cholinomimetics, acetylcholine antagonists and some other compounds of pharmacological interest were administered electrophoretically near neurones within the vermal cerebellar cortex of anaesthetized (pentobarbitone) and unanaesthetized (cerveau isolé) cats. 2. The neurones were identified by position within the cortex, spontaneous activity, and the responses to afferent and antidromic stimulation. 3. Purkinje cells, but neither granule nor basket cells, were excited by cholinomimetics, and the acetylcholine receptors had muscarinic properties. Excitation was often preceded by depression of the spontaneous firing. 4. Intravenously administered atropine and dihydro-?-erythroidine did not depress the synaptic excitation of cerebellar neurones evoked by impulses in mossy, climbing or parallel fibres. 5. Acetylcholine is thus unlikely to be an excitatory transmitter within the feline cerebellum, particularly at mossy fibre-granule cell synapses, despite the presence of relatively high levels of acetylcholinesterase within mossy fibre terminals.

Crawford, J. M.; Curtis, D. R.; Voorhoeve, P. E.; Wilson, V. J.

1966-01-01

399

Cerebellar mutism caused by arteriovenous malformation of the vermis.  

PubMed

Transient mutism following posterior fossa tumour resection in children is well known in the literature. To our Knowledge, this phenomenon has never been reported without surgical intervention. We report a case of cerebellar mutism secondary haemorrhage from a vermian arteriovenous malformation (AVM), which resolved to ataxic dysarthria after 6 weeks. Embolization of the AVM was performed and the patient's clinical status continued to improve gradually till she became normal 6 months from the insult. The mutism was due to rupture of the AVM which might correlate the cerebellar mutism with the transient vasospasm of the blood vessels supplying the cerebellum. It is possible for a spontaneus posterior fossa bleed to result in transient mutism similar to post surgical mutism. PMID:11303661

Al-Anazi, A; Hassounah, M; Sheikh, B; Barayan, S

2001-02-01

400

Cerebellar glioblastoma genetically defined as a secondary one.  

PubMed

We report here the case of a 29-year-old woman with cerebellar glioblastma. In the present case, tumor lesions were observed in each cerebellar hemisphere. The left-side lesion was diagnosed as glioblastoma, and the right-side lesion as malignant astrocytoma by histopathology. Immunohistochemistry revealed that the tumor cells of the left-side lesion was positive for p53, whereas epidermal growth factor receptors (EGFR) were negative in tumor cells from both sides. Genetic alterations were investigated using a genome DNA microarray (GenoSensor Array 300), which has led us to define this tumor as a secondary glioblastoma. The clinical presentation and genetic findings of this relatively rare entity are discussed. PMID:15803805

Kawarabuki, K; Ohta, T; Hashimoto, N; Wada, K; Maruno, M; Yamaki, T; Ueda, S

401

The cerebellar microcircuit as an adaptive filter: experimental and computational evidence.  

PubMed

Initial investigations of the cerebellar microcircuit inspired the Marr-Albus theoretical framework of cerebellar function. We review recent developments in the experimental understanding of cerebellar microcircuit characteristics and in the computational analysis of Marr-Albus models. We conclude that many Marr-Albus models are in effect adaptive filters, and that evidence for symmetrical long-term potentiation and long-term depression, interneuron plasticity, silent parallel fibre synapses and recurrent mossy fibre connectivity is strikingly congruent with predictions from adaptive-filter models of cerebellar function. This congruence suggests that insights from adaptive-filter theory might help to address outstanding issues of cerebellar function, including both microcircuit processing and extra-cerebellar connectivity. PMID:19997115

Dean, Paul; Porrill, John; Ekerot, Carl-Fredrik; Jörntell, Henrik

2009-12-09

402

Calcium control of transmitter release at a cerebellar synapse  

Microsoft Academic Search

The manner in which presynaptic Ca2+ influx controls the release of neurotransmitter was investigated at the granule cell to Purkinje cell synapse in rat cerebellar slices. Excitatory postsynaptic currents were measured using whole-cell voltage clamp, and changes in presynaptic Ca2+ influx were determined with the Ca2+-sensitive dye furaptra. We manipulated presynaptic Ca2+ entry by altering external Ca2+ levels and by

I. M. Mintz; B. L. Sabatini; W. G. Regehr

1995-01-01

403

Distribution of cerebellar tonsil position: implications for understanding Chiari malformation.  

PubMed

Object Prior attempts to define normal cerebellar tonsil position have been limited by small numbers of patients precluding analysis of normal distribution by age group. The authors' objective in the present study was to analyze cerebellar tonsil location in every age range. Methods Two thousand four hundred patients were randomly selected from a database of 62,533 consecutive patients undergoing MRI and were organized into 8 age groups. Magnetic resonance images were directly examined for tonsil location, morphology, and other features. Patients with a history or imaging findings of posterior fossa abnormalities unrelated to Chiari malformation (CM) were excluded from analysis. The caudal extent of the cerebellar tonsils was measured at the midsagittal and lowest parasagittal positions. Results The mean tonsil height decreased slightly with advancing age into young adulthood and increased with advancing age in the adult age range. An increasing age in the adult age range was associated with a decreased likelihood of a tonsil position 5 mm or more below the foramen magnum (p = 0.0004). In general, the lowest tonsil position in each age group was normally distributed. Patients with pegged morphology were more likely to have a tonsil location at least 5 mm below the foramen magnum (85%), as compared with those having intermediate (38%) or rounded (2%) morphology (p < 0.0001). Female sex was associated with a lower mean tonsil position (p < 0.0001). Patients with a lower tonsil position also tended to have an asymmetrical tonsil position, usually lower on the right (p < 0.0001). Conclusions Cerebellar tonsil position follows an essentially normal distribution and varies significantly by age. This finding has implications for advancing our understanding of CM. PMID:23767890

Smith, Brandon W; Strahle, Jennifer; Bapuraj, J Rajiv; Muraszko, Karin M; Garton, Hugh J L; Maher, Cormac O

2013-06-14

404

Cerebellar medullomyoblastoma with advanced neuronal differentiation and hamartomatous component  

Microsoft Academic Search

This report describes an unusual medullo-myoblastoma which developed in the cerebellar vermis of a 6-year-old girl. Histological investigation showed a highly cellular and predominantly undifferentiated tumor. Myogenic differentiation was prominent in clusters of large tumor cells with eosinophilic cytoplasm and immunoreactivity for desmin and myoglobin. Electron microscopy revealed the presence of immature Z-bands. Immunohistochemically, numerous cells showed incipient expression of

T. Höll; P. Kleihues; M. G. Yasargil; O. D. Wiestler

1991-01-01

405

Spontaneous Total Thrombosis of Distal Superior Cerebellar Artery Aneurysm  

Microsoft Academic Search

Summary.  \\u000a We report the case of an aneurysm of the distal segment of the superior cerebellar artery (SCA) which showed complete spontaneous\\u000a thrombosis. Initial angiography performed in another institution showed 3 non-ruptured aneurysms located on the right distal\\u000a SCA, C3 segment of the right internal carotid artery (ICA) and left basilar artery (BA) – SCA bifurcation. The patient had\\u000a two

H. Ohta; N. Sakai; I. Nagata; H. Sakai; A. Shindo; H. Kikuchi

2001-01-01

406

Abnormal cerebellar morphometry in abstinent adolescent marijuana users  

Microsoft Academic Search

Functional neuroimaging data from adults have, in general, revealed frontocerebellar dysfunction associated with acute and chronic marijuana (MJ) use. The goal of this study was to characterize cerebellar volume in adolescent chronic MJ users following 1 month of monitored abstinence. Participants were MJ users (n=16) and controls (n=16) aged 16–18years. Extensive exclusionary criteria included history of psychiatric or neurologic disorders.

Krista Lisdahl Medina; Bonnie J. Nagel; Susan F. Tapert

2010-01-01

407

Cerebellar ataxia with elevated cerebrospinal free sialic acid (CAFSA)  

PubMed Central

In order to identify new metabolic abnormalities in patients with complex neurodegenerative disorders of unknown aetiology, we performed high resolution in vitro proton nuclear magnetic resonance spectroscopy on patient cerebrospinal fluid (CSF) samples. We identified five adult patients, including two sisters, with significantly elevated free sialic acid in the CSF compared to both the cohort of patients with diseases of unknown aetiology (n = 144; P < 0.001) and a control group of patients with well-defined diseases (n = 91; P < 0.001). All five patients displayed cerebellar ataxia, with peripheral neuropathy and cognitive decline or noteworthy behavioural changes. Cerebral MRI showed mild to moderate cerebellar atrophy (5/5) as well as white matter abnormalities in the cerebellum including the peridentate region (4/5), and at the periventricular level (3/5). Two-dimensional gel analyses revealed significant hyposialylation of transferrin in CSF of all patients compared to age-matched controls (P < 0.001)—a finding not present in the CSF of patients with Salla disease, the most common free sialic acid storage disorder. Free sialic acid content was normal in patients’ urine and cultured fibroblasts as were plasma glycosylation patterns of transferrin. Analysis of the ganglioside profile in peripheral nerve biopsies of two out of five patients was also normal. Sequencing of four candidate genes in the free sialic acid biosynthetic pathway did not reveal any mutation. We therefore identified a new free sialic acid syndrome in which cerebellar ataxia is the leading symptom. The term CAFSA is suggested (cerebellar ataxia with free sialic acid).

Sedel, F.; Vanderver, A.; Engelke, U. F. H.; Barritault, J.; Yang, B. Z.; Kulkarni, B.; Adams, D. R.; Clot, F.; Ding, J. H.; Kaneski, C. R.; Verheijen, F. W.; Smits, B. W.; Seguin, F.; Brice, A.; Vanier, M. T.; Huizing, M.; Schiffmann, R.; Durr, A.; Wevers, R. A.

2009-01-01

408

Dissecting Aneurysm of the Peripheral Posterior Inferior Cerebellar Artery  

Microsoft Academic Search

Summary  ¶?Dissecting aneurysms of intracranial posterior circulation have recently been shown to be less uncommon than previously\\u000a thought. However, those involving the posterior inferior cerebellar artery (PICA) and not vertebral artery at all are extremely\\u000a rare. We report here a case of a patient with a dissecting aneurysm of the lateral medullary segment of PICA which presented\\u000a as subarachnoid haemorrhage. The

Y. Kanou; K. Arita; K. Kurisu; F. Ikawa; K. Eguchi; S. Monden; K. Watanabe

2000-01-01

409

Modulating human procedural learning by cerebellar transcranial direct current stimulation.  

PubMed

Neuroimaging studies suggest that the cerebellum contributes to human cognitive processing, particularly procedural learning. This type of learning is often described as implicit learning and involves automatic, associative, and unintentional learning processes. Our aim was to investigate whether cerebellar transcranial direct current stimulation (tDCS) influences procedural learning as measured by the serial reaction time task (SRTT), in which subjects make speeded key press responses to visual cues. A preliminary modeling study demonstrated that our electrode montage (active electrode over the cerebellum with an extra-cephalic reference) generated the maximum electric field amplitude in the cerebellum. We enrolled 21 healthy subjects (aged 20-49 years). Participants did the SRTT, a visual analogue scale and a visual attention task, before and 35 min after receiving 20-min anodal and sham cerebellar tDCS in a randomized order. To avoid carry-over effects, experimental sessions were held at least 1 week apart. For our primary outcome measure (difference in RTs for random and repeated blocks) anodal versus sham tDCS, RTs were significantly slower for sham tDCS than for anodal cerebellar tDCS (p = 0.04), demonstrating that anodal tDCS influenced implicit learning processes. When we assessed RTs for procedural learning across the one to eight blocks, we found that RTs changed significantly after anodal stimulation (interaction "time" × "blocks 1/8": anodal, p = 0.006), but after sham tDCS, they remained unchanged (p = 0.094). No significant changes were found in the other variables assessed. Our finding that anodal cerebellar tDCS improves an implicit learning type essential to the development of several motor skills or cognitive activity suggests that the cerebellum has a critical role in procedural learning. tDCS could be a new tool for improving procedural learning in daily life in healthy subjects and for correcting abnormal learning in neuropsychiatric disorders. PMID:23328908

Ferrucci, Roberta; Brunoni, Andre R; Parazzini, Marta; Vergari, Maurizio; Rossi, Elena; Fumagalli, Manuela; Mameli, Francesca; Rosa, Manuela; Giannicola, Gaia; Zago, Stefano; Priori, Alberto

2013-08-01

410

Effects of chronic ethanol exposure on cultured cerebellar granule cells  

Microsoft Academic Search

The aim of this study was to investigate the lipid content and composition of rat cerebellar granule cells grown in the presence\\u000a of ethanol (40, 55, or 80 mM) during in vitro differentiation. Quantitative analyses showed no effects of 40 mM ethanol, whereas a significant increase of total cholesterol was observed at 55 mM. Cells exposed to the highest ethanol

Fausta Omodeo-Salé; Marina Pitto; Massimo Masserini; Paola Palestini

1995-01-01

411

Rebound Discharge in Deep Cerebellar Nuclear Neurons In Vitro  

Microsoft Academic Search

Neurons of the deep cerebellar nuclei (DCN) play a critical role in defining the output of cerebellum in the course of encoding\\u000a Purkinje cell inhibitory inputs. The earliest work performed with in vitro preparations established that DCN cells have the\\u000a capacity to translate membrane hyperpolarizations into a rebound increase in firing frequency. The primary means of distinguishing\\u000a between DCN neurons

Reza Tadayonnejad; Dustin Anderson; Michael L. Molineux; W. Hamish Mehaffey; Kusala Jayasuriya; Ray W. Turner

2010-01-01

412

Fusiform aneurysm of the superior cerebellar artery: short review article  

Microsoft Academic Search

Summary  Fusiform superior cerebellar artery (SCA) aneurysms are quite rare and only 9 cases have been reported in the literature.\\u000a Fusiform aneurysms are a small group of cerebral aneurysms among the most difficult to treat. The therapeutic approaches in\\u000a the limited number cited in the literature include surgery and endovascular occlusion. Surgical techniques which have been\\u000a used are parent artery occlusion,

B. Atalay; N. Altinors; C. Yilmaz; H. Caner; O. Ozger

2007-01-01

413

Cortical and cerebellar activation induced by reflexive and voluntary saccades  

Microsoft Academic Search

Reflexive saccades are driven by visual stimulation whereas voluntary saccades require volitional control. Behavioral and\\u000a lesional studies suggest that there are two separate mechanisms involved in the generation of these two types of saccades.\\u000a This study investigated differences in cerebral and cerebellar activation between reflexive and self-paced voluntary saccadic\\u000a eye movements using functional magnetic resonance imaging. In two experiments (whole

Caroline K. L. Schraa-Tam; Phillippus van Broekhoven; Josef N. van der Geest; Maarten A. Frens; Marion Smits; Aad van der Lugt

2009-01-01

414

Progesterone increases oligodendroglial cell proliferation in rat cerebellar slice cultures  

Microsoft Academic Search

We have previously demonstrated that progesterone significantly increases the rate of myelination in organotypic slice cultures of 7-day-old rat and mouse cerebellum. Here, we show that progesterone (20?M) stimulates the proliferation of oligodendrocyte precursors in cultured cerebellar slices of 7-day-old rats. The steroid increased the number of pre-oligodendrocytes (NG2+, O4+) and to some extent of oligodendrocyte precursors, corresponding to an

A. M. Ghoumari; E. E. Baulieu; M. Schumacher

2005-01-01

415

Cerebellar volumes in newly diagnosed and chronic epilepsy  

Microsoft Academic Search

.   Cerebellar atrophy is assumed to be a common finding in patients suffering from epilepsy. Anticonvulsants as well as seizure\\u000a activity itself have been considered to be responsible for it but many studies have addressed these questions in specialised\\u000a centres for epilepsy thus having a referral bias towards patients with severe epileptic syndromes. The purpose of this study\\u000a was: 1.

G. Hagemann; L. Lemieux; S. L. Free; K. Krakow; A. D. Everitt; B. E. Kendall; J. M. Stevens; S. D. Shorvon

2002-01-01

416

Isolated cerebellar tuberculoma mimicking posterior cranial fossa tumour.  

PubMed

Isolated central nervous system (CNS) tuberculoma is a rare disease. This disease is associated with high morbidity and mortality, despite modern methods of detection and treatment. CNS tuberculosis can present as meningitis, arachnoiditis, tuberculomas or the uncommon form of tuberculous subdural empyema and brain abscess. We present the clinical, radiological and pathological findings of cerebellar tuberculoma in an Iranian immunocompetent patient mimicking a malignant tumour. PMID:23966456

Binesh, Fariba; Zahir, Shokouh Taghipour; Bovanlu, Taghi Roshan

2013-08-21

417

?-Catenin Is Critical for Cerebellar Foliation and Lamination  

PubMed Central

The cerebellum has a conserved foliation pattern and a well-organized layered structure. The process of foliation and lamination begins around birth. ?-catenin is a downstream molecule of Wnt signaling pathway, which plays a critical role in tissue organization. Lack of ?-catenin at early embryonic stages leads to either prenatal or neonatal death, therefore it has been difficult to resolve its role in cerebellar foliation and lamination. Here we used GFAP-Cre to ablate ?-catenin in neuronal cells of the cerebellum after embryonic day 12.5, and found an unexpected role of ?-catenin in determination of the foliation pattern. In the mutant mice, the positions of fissure formation were changed, and the meninges were improperly incorporated into fissures. At later stages, some lobules were formed by Purkinje cells remaining in deep regions of the cerebellum and the laminar structure was dramatically altered. Our results suggest that ?-catenin is critical for cerebellar foliation and lamination. We also found a non cell-autonomous role of ?-catenin in some developmental properties of major cerebellar cell types during specific stages.

Wen, Jing; Yang, Hong-Bin; Zhou, Bing; Lou, Hui-Fang; Duan, Shumin

2013-01-01

418

In vivo calcium imaging of circuit activity in cerebellar cortex.  

PubMed

In vivo two-photon calcium imaging provides the opportunity to monitor activity in multiple components of neural circuitry at once. Here we report the use of bulk-loading of fluorescent calcium indicators to record from axons, dendrites, and neuronal cell bodies in cerebellar cortex in vivo. In cerebellar folium crus IIa of anesthetized rats, we imaged the labeled molecular layer and identified all major cellular structures: Purkinje cells, interneurons, parallel fibers, and Bergmann glia. Using extracellular stimuli we evoked calcium transients corresponding to parallel fiber beam activity. This beam activity triggered prolonged calcium transients in interneurons, consistent with in vitro evidence for synaptic activation of N-methyl-d-aspartate receptors via glutamate spillover. We also observed spontaneous calcium transients in Purkinje cell dendrites that were identified as climbing-fiber-evoked calcium spikes by their size, time course, and sensitivity to AMPA receptor antagonist. Two-photon calcium imaging of bulk-loaded cerebellar cortex is thus well suited to optically monitor synaptic processing in the intact cerebellum. PMID:16079125

Sullivan, Megan R; Nimmerjahn, Axel; Sarkisov, Dmitry V; Helmchen, Fritjof; Wang, Samuel S-H

2005-04-20

419

Cerebellar Contribution to Anger Recognition Deficits in Huntington's Disease.  

PubMed

Although there is increasing evidence that cerebellar loss of grey matter volume (GMV) is associated with affective deficits, this has not been tested for patients suffering from Huntington's disease (HD), who show a pronounced impairment in the recognition of anger. We assessed GMV in 18 symptomatic HD patients and 18 healthy controls using voxel-based morphometry. The GMV of cerebellar subregions was correlated with participants' intensity and accuracy ratings for facial expressions of basic emotions from the Karolinska Directed Emotional Faces (Lundqvist et al. 1998). The patients gave lower and less accurate anger ratings for angry faces than controls. This anger recognition deficit was correlated with atrophy of selected hemispheric and vermal regions of the cerebellum. Furthermore, cerebellar volume reductions of the HD patients were associated with longer disease duration and greater functional impairment. The data imply that anger recognition deficits could potentially serve as indicators of disease onset and progression in HD. Furthermore, the patients might profit from specific affect trainings. PMID:23709228

Scharmüller, Wilfried; Ille, Rottraut; Schienle, Anne

2013-12-01

420

A Cerebellar Deficit in Sensorimotor Prediction Explains Movement Timing Variability  

PubMed Central

A popular theory is that the cerebellum functions as a timer for clocking motor events (e.g., initiation, termination). Consistent with this idea, cerebellar patients have been reported to show greater deficits during hand movements that repeatedly start and stop (i.e., discontinuous movements) compared with continuous hand movements. Yet, this finding could potentially be explained by an alternate theory in which the cerebellum acts as an internal model of limb mechanics. We tested whether a timing or internal model hypothesis best explains results from a circle-drawing task, where individuals trace a circle with the hand at a desired tempo. We first attempted to replicate prior results showing greater impairment for discontinuous versus continuous circling movements, and then asked whether we could improve patient performance by reducing demands in each domain. First, we slowed the movement down to reduce the need to predict and compensate for limb dynamics. Second, we supplied external timing information to reduce the need for an internal event timer. Results showed that we did not replicate the previous findings—cerebellar patients were impaired in both discontinuous and continuous movements. Slowing the movement improved cerebellar performance to near control values. The addition of an external visual timing signal paradoxically worsened timing deficits rather than mitigating them. One interpretation of these combined results is that the cerebellum is indeed functioning as an internal model and is needed to make appropriate predictions for movement initiation and termination.

Bo, Jin; Block, Hannah J.; Clark, Jane E.; Bastian, Amy J.

2008-01-01

421

Respective implications of glutamate decarboxylase antibodies in stiff person syndrome and cerebellar ataxia  

Microsoft Academic Search

BACKGROUND: To investigate whether Stiff-person syndrome (SPS) and cerebellar ataxia (CA) are associated with distinct GAD65-Ab epitope specificities and neuronal effects. METHODS: Purified GAD65-Ab from neurological patients and monoclonal GAD65-Ab with distinct epitope specificities (b78 and b96.11) were administered in vivo to rat cerebellum. Effects of intra-cerebellar administration of GAD65-Ab were determined using neurophysiological and neurochemical methods. RESULTS: Intra-cerebellar administration

Mario U Manto; Christiane S Hampe; Véronique Rogemond; Jérome Honnorat

2011-01-01

422

A comprehensive assessment of cerebellar damage in multiple sclerosis using diffusion tractography and volumetric analysis  

PubMed Central

Background: White matter (WM) and grey matter (GM) brain damage in multiple sclerosis (MS) is widespread, but the extent of cerebellar involvement and impact on disability needs to be clarified. Objective: This study aimed to assess cerebellar WM and GM atrophy and the degree of fibre coherence in the main cerebellar connections, and their contribution to disability in relapsing–remitting MS (RRMS) and primary progressive MS (PPMS). Methods: Fourteen patients with RRMS, 12 patients with PPMS and 16 healthy controls were recruited. Cerebellar WM and GM volumes and tractography-derived measures from the middle and superior cerebellar peduncles, including fractional anisotropy (FA), mean diffusivity (MD), and directional diffusivities, were quantified from magnetic resonance imaging (MRI). Patients were assessed on clinical scores, including the MS Functional Composite score subtests. Linear regression models were used to compare imaging measures between 12 RRMS, 11 PPMS and 16 controls, and investigate their association with clinical scores. Results: Patients with PPMS showed reduced FA and increased radial diffusivity in the middle cerebellar peduncle compared with controls and patients with RRMS. In PPMS, lower cerebellar WM volume was associated with worse performance on the upper limb test. In the same patient group, we found significant relationships between superior cerebellar peduncle FA and upper limb function, and between superior cerebellar peduncle FA, MD and radial diffusivity and speed of walking. Conclusion: These findings indicate reduced fibre coherence in the main cerebellar connections, and link damage in the whole cerebellar WM, and, in particular, in the superior cerebellar peduncle, to motor deficit in PPMS.

Anderson, VM; Wheeler-Kingshott, CAM; Abdel-Aziz, K; Miller, DH; Toosy, A; Thompson, AJ; Ciccarelli, O

2011-01-01

423

Fetal cerebellar hemorrhage in parvovirus-associated non-immune hydrops fetalis.  

PubMed

We report two cases of fetal cerebellar hemorrhage in the setting of parvovirus-associated hydrops fetalis and fetal blood transfusion. In both cases, the cerebellar hemorrhage was diagnosed by fetal magnetic resonance imaging after intrauterine blood transfusion. To our knowledge, this is the first report of fetal cerebellar hemorrhage in the setting of parvovirus-associated hydrops fetalis, and may be the result of cerebrovascular changes both during and after the transfusion. PMID:17763280

Glenn, Orit A; Bianco, Katherine; Barkovich, A James; Callen, Peter W; Parer, Julian T

2007-10-01

424

Flow Visualizations and Extended Thrust Time Histories of Rotor Vortex Wakes in Descent  

NASA Astrophysics Data System (ADS)

An experimental study is performed on a three-bladed rotor model in a water tow tank. The blade pitch and rotational velocity, the rotor plane angle of attack (descent angle), and the carriage speed are all varied in order to simulate a wide range of rotorcraft operating states, with the focus being on descent speeds and angles where the rotor is operating in or near vortex ring state an area in which there is currently very little available data. Circulation and blade Reynolds numbers are of order 10^5. Flow visualization is done by injecting air bubbles and fluorescent dye tangentially from the blade tips to mark the vortex core, showing the development of both short-wave (sinuous) and long-wave (leapfrogging) instabilities on the helical vortices in the wake. Strain gages are used to record transient loads, allowing a correlation between the rotor thrust performance and the development of the vortex wake. Test runs are performed for extended periods up to 500 rotor revolutions demonstrating the repeatability of the patterns of thrust variation. The data indicate that as the instabilities develop, adjacent vortices merge and form thick vortex rings, especially during descent. Periodic shedding of these rings from the wake associated with vortex ring state is observed, resulting in peak-to-peak thrust fluctuations of up to 95% of the mean and occurring at regular intervals of 2050 rotor revolutions, depending on flow parameters. Preliminary particle image velocimetry (PIV) data provide a quantitative measure of the entire rotor flow field for the case of a hovering rotor. The data yield additional information on the vortex filament instability, in particular the axial flow in the vortex cores.

Stack, James; Caradonna, Frank; Savas, Omer

2003-11-01

425

The unusual phase curve of Titan's surface observed by Huygens’ Descent Imager/Spectral Radiometer  

NASA Astrophysics Data System (ADS)

The Descent Imager/Spectral Radiometer onboard Huygens observed Titan's surface through the atmospheric methane windows [Tomasko, M.G., Doose, L., Engel, S., Dafoe, L.E., West, R., Lemmon, M., Karkoschka, E., See, C., 2008. A model of Titan's aerosols based on measurements made inside the atmosphere. Planet. Space Sci. 56, 669-707]. Infrared spectra obtained during the last stage of the descent, for which the atmospheric contribution is negligible, show that the reflectance of the surface around the sit increases with decreasing solar phase angle. Combining these with a spectrum reconstructed from reflected lamp light [Schröder, S.E., Keller, H.U., 2008. The reflectance spectrum of Titan's surface at the Huygens landing site determined by the Descent Imager/Spectral Radiometer. Planet. Space Sci. 56, 753-769] reveals a strong increase in reflectance towards zero phase angle: the opposition surge. Both shadow hiding and coherent backscatter are required to fit the phase curve with the Hapke [2002. Bidirectional Reflectance Spectroscopy 5. The Coherent Backscatter Opposition Effect and Anisotropic Scattering. Icarus 157, 523-534] model. We find the particle phase function below 60? phase angle to be close to isotropic, which is highly unusual for the surfaces of planetary bodies. A terrain with similar scattering properties has been identified on Triton [Lee, P., Helfenstein, P., Veverka, J., McCarthy, D., 1992. Anomalous-scattering region on Triton. Icarus 99, 82-97], and a connection with the tholins thought to be present on both worlds seems plausible. Indeed, tholin laboratory analogs are found to scatter in similar fashion [Lüthi, 2008. Remote sensing of the surface of Titan: Photometric properties, comparison with analogues, and future microscopic observations. Ph.D. Thesis, Philosophisch-naturwissenschaftlichen Fakultät, Universität Bern]. We conclude that Titan's unusual phase curve is consistent with the presence of tholins on the surface. Our result provides a lower boundary condition for Titan atmosphere models and as such may aid the ongoing analysis of Cassini data.

Schröder, S. E.; Keller, H. U.

2009-12-01

426

Progenitors from the postnatal forebrain subventricular zone differentiate into cerebellar-like interneurons and cerebellar-specific astrocytes upon transplantation  

PubMed Central

Forebrain subventricular zone (SVZ) progenitor cells give rise to glia and olfactory bulb interneurons during early postnatal life in rats. We investigated the potential of SVZ cells to alter their fate by transplanting them in a heterotypic neurogenic and gliogenic environment-the cerebellum. Transplanted cells were examined 1 to 7 weeks and 6 months post-transplantation. Forebrain progenitors populated the cerebellum and differentiated into oligodendrocytes, cerebellar-specific Bergmann glia and velate astrocytes, and neurons. The transplanted cells that differentiated into neurons maintained an interneuronal fate: they were GABA-positive, expressed interneuronal markers, such as calretinin, and exhibited membrane properties that are characteristic of interneurons. However, the transplanted interneurons lost the expression of the olfactory bulb transcription factors Tbr2 and Dlx1, and acquired a cerebellar-like morphology. Forebrain SVZ progenitors thus have the potential to adapt to new environment and integrate into diverse regions, and may be useful tool in transplantation strategies.

Milosevic, Ana; Noctor, Stephen C.; Martinez-Cerdeno, Veronica; Kriegstein, Arnold R.; Goldman, James E.

2008-01-01

427

Steepest descent method with a generalized Armijo search for quasiconvex functions on Riemannian manifolds  

NASA Astrophysics Data System (ADS)

This paper extends the full convergence of the steepest descent method with a generalized Armijo search and a proximal regularization to solve minimization problems with quasiconvex objective functions on complete Riemannian manifolds. Previous convergence results are obtained as particular cases and some examples in non-Euclidian spaces are given. In particular, our approach can be used to solve constrained minimization problems with nonconvex objective functions in Euclidian spaces if the set of constraints is a Riemannian manifold and the objective function is quasiconvex in this manifold.

Papa Quiroz, E. A.; Quispe, E. M.; Oliveira, P. Roberto

2008-05-01

428

A Biological Gradient Descent for Prediction Through a Combination of STDP and Homeostatic Plasticity.  

PubMed

Identifying, formalizing, and combining biological mechanisms that implement known brain functions, such as prediction, is a main aspect of research in theoretical neuroscience. In this letter, the mechanisms of spike-timing-dependent plasticity and homeostatic plasticity, combined in an original mathematical formalism, are shown to shape recurrent neural networks into predictors. Following a rigorous mathematical treatment, we prove that they implement the online gradient descent of a distance between the network activity and its stimuli. The convergence to an equilibrium, where the network can spontaneously reproduce or predict its stimuli, does not suffer from bifurcation issues usually encountered in learning in recurrent neural networks. PMID:24001342

Galtier, Mathieu N; Wainrib, Gilles

2013-09-03

429

Cohomological descent theory for a morphism of stacks and for equivariant derived categories  

SciTech Connect

In the paper, we find necessary and sufficient conditions under which, if X{yields}S is a morphism of algebraic varieties (or, in a more general case, of stacks), the derived category of S can be recovered by using the tools of descent theory from the derived category of X. We show that for an action of a linearly reductive algebraic group G on a scheme X this result implies the equivalence of the derived category of G-equivariant sheaves on X and the category of objects in the derived category of sheaves on X with a given action of G on each object. Bibliography: 18 titles.

Elagin, Alexei D [A. A. Kharkevich Institute for Information Transmission Problems, Russian Academy of Sciences, Moscow (Russian Federation)

2011-04-30

430

Adaptive wavefront correction using a VLSI implementation of the parallel gradient descent algorithm  

NASA Astrophysics Data System (ADS)

An adaptive laser beam focusing system using a 127 channel liquid crystal phase modulator is presented. The controller for the system is a circuit built with prototype VLSI chips that implement the stochastic parallel gradient descent algorithm. The controller is driven by a scalar laser beam quality metric and can run at the rate of 150 kHz. The system performance is characterized and a secondary control loop manipulating one of the algorithm parameters is experimentally investigated. The performance of the system is reported and performance improvements obtained by using the recent history of the beam quality metric to control an algorithm parameter is demonstrated.

Carhart, Gary W.; Vorontsov, Mikhail A.; Cohen, Marc H.; Cauwenberghs, Gert; Edwards, R. Timothy

1999-11-01

431

JC Virus Variant Associated with Cerebellar Atrophy in a Patient with AIDS?  

PubMed Central

The human polyomavirus JC virus (JCV) is the agent of progressive multifocal leukoencephalopathy (PML). It has also recently been involved in cerebellar atrophy. Factors involved in this entity are elusive. We present a case of a human immunodeficiency virus (HIV)-infected patient with PML and cerebellar atrophy. In addition to a compartmentalization of JCV strains between urine, cerebrospinal fluid, and cerebellum, specific rearrangements in the JCV regulatory region were observed in the cerebellum, resulting in alterations of transcription factor binding sites. Our data underline the importance of searching for JCV in HIV-infected patients with cerebellar disorders and suggest that mutations in the regulatory region may be involved in cerebellar degeneration.

Roux, Damien; Bouldouyre, Marie-Anne; Mercier-Delarue, Severine; Seilhean, Danielle; Zagdanski, Anne-Marie; Delaugerre, Constance; Simon, Francois; Molina, Jean-Michel; Legoff, Jerome

2011-01-01

432

Crossed cerebellar diaschisis: a radiological finding in status epilepticus not to miss.  

PubMed

Crossed Cerebellar Diaschisis refers to the hypometabolism and loss of functional activity in cerebellar hemisphere contralateral to the supratentorial lesion. It is well recognised following stroke but less commonly reported in patients with status epilepticus. We report a case of status epilepticus with initial MRI findings consistent with Crossed Cerebellar Diaschisis.The abnormalities resolved on successful treatment but subsequently recurred during a second episode of complex partial status epilepticus. We will discuss the images and pathophysiology of crossed Cerebellar diaschisis in status epilepticus. PMID:24108877

Zaidi, Syed

2013-11-01

433

Cerebellar Output in Zebrafish: An Analysis of Spatial Patterns and Topography in Eurydendroid Cell Projections  

PubMed Central

The cerebellum is a brain region responsible for motor coordination and for refining motor programs. While a great deal is known about the structure and connectivity of the mammalian cerebellum, fundamental questions regarding its function in behavior remain unanswered. Recently, the zebrafish has emerged as a useful model organism for cerebellar studies, owing in part to the similarity in cerebellar circuits between zebrafish and mammals. While the cell types composing their cerebellar cortical circuits are generally conserved with mammals, zebrafish lack deep cerebellar nuclei, and instead a majority of cerebellar output comes from a single type of neuron: the eurydendroid cell. To describe spatial patterns of cerebellar output in zebrafish, we have used genetic techniques to label and trace eurydendroid cells individually and en masse. We have found that cerebellar output targets the thalamus and optic tectum, and have confirmed the presence of pre-synaptic terminals from eurydendroid cells in these structures using a synaptically targeted GFP. By observing individual eurydendroid cells, we have shown that different medial-lateral regions of the cerebellum have eurydendroid cells projecting to different targets. Finally, we found topographic organization in the connectivity between the cerebellum and the optic tectum, where more medial eurydendroid cells project to the rostral tectum while lateral cells project to the caudal tectum. These findings indicate that there is spatial logic underpinning cerebellar output in zebrafish with likely implications for cerebellar function.

Heap, Lucy A.; Goh, Chi Ching; Kassahn, Karin S.; Scott, Ethan K.

2013-01-01

434

Flavoprotein imaging in the cerebellar cortex in vivo: cellular and metabolic basis and insights into cerebellar function  

NASA Astrophysics Data System (ADS)

Flavoprotein autofluorescence is an activity dependent intrinsic signal. Flavoproteins are involved in the electron transport chain and change their fluorescence according to the cellular redox state. We have been using flavoprotein autofluorescence in the cerebellum to examine properties of cerebellar circuits. Studies have also focused on understanding the cellular and metabolic origins of this intrinsic optical signal. Parallel fiber stimulation evokes a beamlike response intersected by bands of decreased fluorescence. The beam response is biphasic, with an early fluorescence increase (light phase) followed by a slower decrease (dark phase). We show this signal originates from flavoproteins as determined by its wavelength selectivity and sensitivity to blockers of the electron transport chain. Selectively blocking glutamate receptors abolished the on-beam light phase with the dark phase remaining intact. This demonstrates that the light phase is due to postsynaptic neuronal activation and suggests the dark phase is primarily due to glial activation. The bands of reduced fluorescence intersecting the beam are primarily neuronal in origin, mediated by GABAergic transmission, and due to the inhibitory action of molecular layer interneurons on Purkinje cells and the interneurons themselves. This parasagittally organized molecular layer inhibition differentially modulates the spatial pattern of cerebellar cortical activity. Flavoprotein imaging also reveals the functional architectures underlying the responses to inferior olive and peripheral whisker pad stimulation. Therefore, flavoprotein autofluorescence imaging is providing new insights into cerebellar cortical function and neurometabolic coupling.

Gao, Wangcai; Chen, Gang; Ebner, Timothy J.

2009-02-01

435

Studying the Effect of Adaptive Momentum in Improving the Accuracy of Gradient Descent Back Propagation Algorithm on Classification Problems  

NASA Astrophysics Data System (ADS)

Despite being widely used in the practical problems around the world, Gradient Descent Back-propagation algorithm comes with problems like slow convergence and convergence to local minima. Previous researchers have suggested certain modifications to improve the convergence in gradient Descent Back-propagation algorithm such as careful selection of input weights and biases, learning rate, momentum, network topology, activation function and value for 'gain' in the activation function. This research proposed an algorithm for improving the working performance of back-propagation algorithm which is 'Gradient Descent with Adaptive Momentum (GDAM)' by keeping the gain value fixed during all network trials. The performance of GDAM is compared with 'Gradient Descent with fixed Momentum (GDM)' and 'Gradient Descent Method with Adaptive Gain (GDM-AG)'. The learning rate is fixed to 0.4 and maximum epochs are set to 3000 while sigmoid activation function is used for the experimentation. The results show that GDAM is a better approach than previous methods with an accuracy ratio of 1.0 for classification problems like Wine Quality, Mushroom and Thyroid disease.

Rehman, Muhammad Zubair; Nawi, Nazri Mohd.

436

Design optimisation and flight validation of a stratospheric descent low cost probe in scientific balloon missions  

NASA Astrophysics Data System (ADS)

This paper summarises the activities conducted at CISAS - University of Padova in designing and optimising a low cost scientific probe to be used in earth atmospheric descents from balloon reached stratospheric altitudes of around 40 kilometre. As part of the collaboration with Italian Space Agency on HASI instrument for Huygens mission, University of Padova has been conducting for several years a scientific balloon launch activity from Italian Space Agency Stratospheric Balloon Launch base in Trapani Milo, Sicily. The expertise and know how achieved during these years have contributed to building a strong and confident engineering team able to cope with the different and challenging requirements of boomerang mode balloon missions, which range from thermal and mechanical environmental issues to electronics design, system integration and data handling. Design of the probe used in 2003 is here presented, focusing on mechanical, electronic, thermal and fluidodynamic optimisations conducted in order to increase available space for payloads, guarantee accessibility and maintainability of subsystems and improve performance during foreseen mission operations. Overview of the 2003 flight then presented underlying the successful operation of the system in acquiring its 84 sensor channels of 12 different scientific instruments , sampled during ascent, drift and descent phase.

Carlo Bettanini, C. B.; Giacomo Colombatti, G. C.; Francesco Angrilli, F. A.; Giannandrea Bianchini, G. B.; Enrico Flamini, E. F.

437

Factors associated with psychological distress among women of African descent at high risk for BRCA mutations.  

PubMed

Little is known about psychological distress among women of African descent who are at high risk for a BRCA mutation. This is a group for whom breast cancer risk reduction is critical due to the group's high rates of breast cancer mortality. Distress is important to consider as it may reduce the potential benefit of genetic counseling and negatively affect decision making related to risk reduction. The goals of the current study were to examine breast cancer-specific distress and depressive symptoms in women of African descent at who are at high risk for a BRCA mutation and to identify background factors associated with these outcomes. Participants were 148 high-risk African American and Caribbean women who were part of a larger study that offered participants BRCA counseling at no cost. Participants completed the Impact of Events Scale, which assessed breast cancer-specific distress, and the Center of Epidemiological Studies-Depression Scale, which assessed depressive symptoms. Results of analyses revealed that almost half of the sample achieved scores indicating high and clinically significant breast cancer-specific distress, while almost one-third had clinically significant depression scores. Results further showed that low income was significantly associated with cancer-specific distress, while having a cancer diagnosis was significantly associated with depressive symptoms. These results underscore the need for targeted psychological support throughout the genetic risk assessment process for this particular high-risk group. PMID:22736212

Cukier, Yael R; Thompson, Hayley S; Sussner, Katarina; Forman, Andrea; Jandorf, Lina; Edwards, Tiffany; Bovbjerg, Dana H; Schwartz, Marc D; Valdimarsdottir, Heiddis B

2012-06-27

438

[People of African descent in the region of the Americas and health equity].  

PubMed

The Region of the Americas and the Caribbean has a complex demographic profile from an ethnic and racial perspective. One of the largest groups is composed of persons of African descent, who in some countries, such as Brazil and the Dominican Republic, comprise 46 and 84% of the total population, respectively. Recent analyses of the statistics available in some countries of the Region show wide gaps in terms of living conditions and health in these communities, as well as gaps in access to health services. PAHO, through its Public Policy and Health Program, under the Division of Health and Human Development, supports sectorial efforts and those of civil organizations that aim to improve health conditions in this segment of the population, while taking into account their sociodemographic and cultural characteristics. This article briefly summarizes health conditions and access to health services in selected countries, as well as some aspects of the recent changes to the legislation in those countries. Finally, collaborative activities on the part of United Nations agencies and international financial institutions for the benefit of people of African descent and other ethnic minorities are described. PMID:12162849

Torres, Cristina

439

It's Others, Not the Police: Smoking, Reprimand, and Fines among Adults of Korean Descent in California  

PubMed Central

Objective This study assesses the association of immediate social and legal reprimand and current smoking status among Californians of Korean descent. Design Data were drawn from a population-based probability sample using a telephone survey conducted by bilingual, professional interviewers (N=2085). About 85.0% of eligible respondents completed interviews and 86.3% of participants preferred to be interviewed in Korean. Main Outcome Measure Smoking status was measured using CDC criteria, ever smoked 100 cigarettes and currently smoke every day or some days. Results and Conclusion Reports of immediate criticism by others in several settings was associated with non-smoking, but likelihood of immediate legal penalties was unrelated. Participants were far less likely to expect legal than social sanction. Results were replicated after controlling for reinforcers of smoking and ecologically relevant variables including models of smoking, primary group social support for smoking, acculturation, gender, acculturation by gender (male) interaction, age, and education. It may be efficacious to target public health interventions encouraging appropriate social sanctions of smoking in public among persons of Korean descent, and to encourage strict enforcement of legal penalties for smoking in public places.

Hofstetter, C. Richard; Hovell, Melbourne F.; Irvin, Veronica L.; Ayers, John W.; Hughes, Suzanne; Kang, Sunny

2009-01-01

440

SLiMDisc: short, linear motif discovery, correcting for common evolutionary descent  

PubMed Central

Many important interactions of proteins are facilitated by short, linear motifs (SLiMs) within a protein's primary sequence. Our aim was to establish robust methods for discovering putative functional motifs. The strongest evidence for such motifs is obtained when the same motifs occur in unrelated proteins, evolving by convergence. In practise, searches for such motifs are often swamped by motifs shared in related proteins that are identical by descent. Prediction of motifs among sets of biologically related proteins, including those both with and without detectable similarity, were made using the TEIRESIAS algorithm. The number of motif occurrences arising through common evolutionary descent were normalized based on treatment of BLAST local alignments. Motifs were ranked according to a score derived from the product of the normalized number of occurrences and the information content. The method was shown to significantly outperform methods that do not discount evolutionary relatedness, when applied to known SLiMs from a subset of the eukaryotic linear motif (ELM) database. An implementation of Multiple Spanning Tree weighting outperformed two other weighting schemes, in a variety of settings.

Davey, Norman E.; Shields, Denis C.; Edwards, Richard J.

2006-01-01

441

Integrative Analysis of Cancer Prognosis Data With Multiple Subtypes Using Regularized Gradient Descent.  

PubMed

In cancer research, high-throughput profiling studies have been extensively conducted, searching for genes/single nucleotide polymorphisms (SNPs) associated with prognosis. Despite seemingly significant differences, different subtypes of the same cancer (or different types of cancers) may share common susceptibility genes. In this study, we analyze prognosis data on multiple subtypes of the same cancer but note that the proposed approach is directly applicable to the analysis of data on multiple types of cancers. We describe the genetic basis of multiple subtypes using the heterogeneity model that allows overlapping but different sets of susceptibility genes/SNPs for different subtypes. An accelerated failure time (AFT) model is adopted to describe prognosis. We develop a regularized gradient descent approach that conducts gene-level analysis and identifies genes that contain important SNPs associated with prognosis. The proposed approach belongs to the family of gradient descent approaches, is intuitively reasonable, and has affordable computational cost. Simulation study shows that when prognosis-associated SNPs are clustered in a small number of genes, the proposed approach outperforms alternatives with significantly more true positives and fewer false positives. We analyze an NHL (non-Hodgkin lymphoma) prognosis study with SNP measurements and identify genes associated with the three major subtypes of NHL, namely, DLBCL, FL, and CLL/SLL. The proposed approach identifies genes different from using alternative approaches and has the best prediction performance. PMID:22851516

Ma, Shuangge; Zhang, Yawei; Huang, Jian; Huang, Yuan; Lan, Qing; Rothman, Nathaniel; Zheng, Tongzhang

2012-07-31

442

Effects of the Phoenix Lander descent thruster plume on the Martian surface  

NASA Astrophysics Data System (ADS)

The exhaust plume of Phoenix's hydrazine monopropellant pulsed descent thrusters will impact the surface of Mars during its descent and landing phase in the northern polar region. Experimental and computational studies have been performed to characterize the chemical compounds in the thruster exhausts. No undecomposed hydrazine is observed above the instrument detection limit of 0.2%. Forty-five percent ammonia is measured in the exhaust at steady state. Water vapor is observed at a level of 0.25%, consistent with fuel purity analysis results. Moreover, the dynamic interactions of the thruster plumes with the ground have been studied. Large pressure overshoots are produced at the ground during the ramp-up and ramp-down phases of the duty cycle of Phoenix's pulsed engines. These pressure overshoots are superimposed on the 10 Hz quasi-steady ground pressure perturbations with amplitude of about 5 kPa (at touchdown altitude) and have a maximum amplitude of about 20-40 kPa. A theoretical explanation for the physics that causes these pressure perturbations is briefly described in this article. The potential for soil erosion and uplifting at the landing site is also discussed. The objectives of the research described in this article are to provide empirical and theoretical data for the Phoenix Science Team to mitigate any potential problem. The data will also be used to ensure proper interpretation of the results from on-board scientific instrumentation when Martian soil samples are analyzed.

Plemmons, D. H.; Mehta, M.; Clark, B. C.; Kounaves, S. P.; Peach, L. L.; Renno, N. O.; Tamppari, L.; Young, S. M. M.

2008-08-01

443

Cardiovascular disease, diabetes and established risk factors among populations of sub-Saharan African descent in Europe: a literature review  

PubMed Central

Background Most European countries are ethnically and culturally diverse. Globally, cardiovascular disease (CVD) is the leading cause of death. The major risk factors for CVD have been well established. This picture holds true for all regions of the world and in different ethnic groups. However, the prevalence of CVD and related risk factors vary among ethnic groups. Methods This article provides a review of current understanding of the epidemiology of vascular disease, principally coronary heart disease (CHD), stroke and related risk factors among populations of Sub-Sahara African descent (henceforth, African descent) in comparison with the European populations in Europe. Results Compared with European populations, populations of African descent have an increased risk of stroke, whereas CHD is less common. They also have higher rates of hypertension and diabetes than European populations. Obesity is highly prevalent, but smoking rate is lower among African descent women. Older people of African descent have more favourable lipid profile and dietary habits than their European counterparts. Alcohol consumption is less common among populations of African descent. The rate of physical activity differs between European countries. Dutch African-Suriname men and women are less physically active than the White-Dutch whereas British African women are more physically active than women in the general population. Literature on psychosocial stress shows inconsistent results. Conclusion Hypertension and diabetes are highly prevalent among African populations, which may explain their high rate of stroke in Europe. The relatively low rate of CHD may be explained by the low rates of other risk factors including a more favourable lipid profile and the low prevalence of smoking. The risk factors are changing, and on the whole, getting worse especially among African women. Cohort studies and clinical trials are therefore needed among these groups to determine the relative contribution of vascular risk factors, and to help guide the prevention efforts. There is a clear need for intervention studies among these populations in Europe.

Agyemang, Charles; Addo, Juliet; Bhopal, Raj; de Graft Aikins, Ama; Stronks, Karien

2009-01-01

444

Intraparenchymal grafting of cerebellar cell suspensions to the deep cerebellar nuclei of pcd mutant mice, with particular emphasis on re-establishment of a Purkinje cell cortico-nuclear projection  

Microsoft Academic Search

In transplanting embryonic cerebellar grafts to the cerebellar cortex of “Purkinje cell degeneration” (pcd) mutant mice to replace missing Purkinje cells (PC), donor PC leave the graft and migrate to the molecular layer of the host. However, PC axons do not always reach the deep cerebellar nuclei of the host, which would be a key element in restoring much of

Lazaros C. Triarhou; Walter C. Low; Bernardino Ghetti I

1992-01-01

445

Animal Models of Human Cerebellar Ataxias: a Cornerstone for the Therapies of the Twenty-First Century  

Microsoft Academic Search

Cerebellar ataxias represent a group of disabling neurological disorders. Our understanding of the pathogenesis of cerebellar\\u000a ataxias is continuously expanding. A considerable number of laboratory animals with neurological mutations have been reported\\u000a and numerous relevant animal models mimicking the phenotype of cerebellar ataxias are becoming available. These models greatly\\u000a help dissecting the numerous mechanisms of cerebellar dysfunction, a major step

Mario Manto; Daniele Marmolino

2009-01-01

446

Estimation of Pairwise Identity by Descent From Dense Genetic Marker Data in a Population Sample of Haplotypes  

PubMed Central

I present a new approach for calculating probabilities of identity by descent for pairs of haplotypes. The approach is based on a joint hidden Markov model for haplotype frequencies and identity by descent (IBD). This model allows for linkage disequilibrium, and the method can be applied to very dense marker data. The method has high power for detecting IBD tracts of genetic length of 1 cM, with the use of sufficiently dense markers. This enables detection of pairwise IBD between haplotypes from individuals whose most recent common ancestor lived up to 50 generations ago.

Browning, Sharon R.

2008-01-01

447

Effects of Congenital Feline Cerebellar Hypoplasia on Developmental Behavior and the Vestibular System.  

National Technical Information Service (NTIS)

Emphasis is made of the important role of the brain-stem vestibular nuclei in the interrelations of the vestibulo-ocular reflex arc system when the cerebellar structures are not intact, as in the cerebellar hypoplastic cats studied in this report. It appe...

P. J. Dowd

1966-01-01

448

Abnormal cutaneomotor integration in patients with cerebellar syndromes: a transcranial magnetic stimulation study  

Microsoft Academic Search

Objective: To examine the sensorimotor interactions in cerebellar patients.Methods: We investigated the effects of electrical stimulation of the second (D2) and fifth (D5) fingers on the amplitude of motor evoked potentials (MEPs) in response to transcranial magnetic stimulation and transcranial electrical stimulation (TES) in the relaxed right abductor digiti minimi muscles of 7 patients with cerebellar syndromes and of 14

Stefano Tamburin; Antonio Fiaschi; Annalisa Andreoli; Antonio Forgione; Paolo Manganotti; Giampietro Zanette

2003-01-01

449

Deficits in phasic muscle force generation explain insufficient compensation for interaction torque in cerebellar patients  

Microsoft Academic Search

A simple paradigm was used to investigate how patients with cerebellar lesions cope with the need to correct for joint interactions during a multi-joint movement. Normal subjects and patients with cerebellar degeneration performed fast unconstrained elbow flexions with the instruction to voluntarily fixate the shoulder joint. Angular kinematics and inverse dynamics analyses were performed. A susceptibility index quantified how strong-concomitant

A. Boose; J. Dichgans; H. Topka

1999-01-01

450