Population structure of an orchid mycorrhizal fungus with genus-wide specificity.

Fundamental life history processes of mycorrhizal fungi with inconspicuous fruiting bodies can be difficult to elucidate. In this study we investigated the species identities and life history of the orchid mycorrhizal Tulasnella fungi, which associate with the south eastern Australia orchid genus Chiloglottis. Tulasnella prima was the primary partner and was found to be associated with all 17 Chiloglottis species across a range of >1000 km, and to occur in the two edaphic conditions investigated (soil and sphagnum hammocks). Another Tulasnella species (T. sphagneti) appears to be restricted to moist conditions of alpine sphagnum hammocks. The population genetic structure of the widespread species T. prima, was investigated at 10 simple sequence repeat (SSR) markers and at four cross-amplified SSR loci for T. sphagneti. For both taxa, no sharing of multilocus genotypes was found between sites, but clones were found within sites. Evidence for inbreeding within T. prima was found at 3 of 5 sites. Significant genetic differentiation was found within and between taxa. Significant local positive spatial genetic autocorrelation was detected among non-clonal isolates at the scale of two metres. Overall, the population genetic patterns indicated that in Tulasnella mating occurs by inbreeding and dispersal is typically restricted to short-distances.

"Frontotemporoparietal" dementia: clinical phenotype associated with the c.709-1G>A PGRN mutation.

BACKGROUND: Mutations in the progranulin gene (PGRN) are a major cause of frontotemporal lobar degeneration with tau-negative and ubiquitin-positive neuronal inclusions. Most previous studies aimed at characterizing the clinical and neuropsychological phenotype of PGRN mutation carriers included patients with different PGRN mutations, assuming that the common proposed pathogenetic mechanism of haploinsufficiency will lead to a comparable phenotype. METHODS: We studied 21 patients with a single pathogenic splicing mutation in the PGRN gene (c.709-1G>A) in the same tertiary referral center using homogenous diagnostic criteria and protocols. All patients were of Basque descent. RESULTS: Patients exhibited a variable phenotype both in age at onset and initial symptoms. Behavioral variant frontotemporal dementia (52.4%) and progressive nonfluent aphasia (23.8%) were the most common presenting syndromes. Apathy was the most common behavioral symptom. Patients developed a relatively rapidly progressive dementia with features that led to a secondary diagnosis in 61.9% of cases 2 years after primary diagnosis. Notably, this secondary or tertiary diagnosis was corticobasal syndrome in 47.6% of cases, which confirmed the neuropsychological features of parietal lobe dysfunction seen at the initial assessment in 81.8% of patients. CONCLUSIONS: Patients carrying the c.709-1G>A mutation in the PGRN gene showed heterogeneous clinical and neuropsychological features and commonly developed corticobasal syndrome as the disease progressed.

[Unusual thalamo-mesencephalic infarction: clinico-radiological correlations]. / Infarto tálamo-mesencefálico inusual: correlaciones clinicorradiológicas.

INTRODUCTION: Mesencephalic infarcts usually produce clinical features that allow the lesion to be located with precision, although they do not always match the patterns included in the classical syndromes reported in the literature, as occurs in the case we describe here. CASE REPORT: We report the case of a 73-year-old female with no cardiovascular risk factors, who presented a sudden clinical picture of instability, diplopia, palpebral ptosis and mild hypersomnia. On examining the patient the following manifestations were observed: compromise of the right common oculomotor nerve, up and down vertical gaze palsy, dysmetry of the right limbs and mild long tract signs in the left limbs. Magnetic resonance imaging of the brain revealed right thalamo-mesencephalic infarction in the paramedian territory, which became bilateral in the upper mesencephalon. The aetiological study showed only a carotid atheromatosis. CONCLUSIONS: Cerebellar compromise ipsilateral to a lesion in the common oculomotor nerve in mesencephalic infarcts is a very uncommon clinical variant. The pathogenetic heterogeneity of infarctions involving the mesencephalon makes it necessary to carry out an extensive aetiological study. Magnetic resonance imaging of the brain is an essential tool for understanding the clinical picture and the anatomical structures involved in cases of infrequent cerebral infarction.

Infarto tálamo-mesencefálico inusual: correlaciones clinicorradiológicas / Unusual thalamo-mesencephalic infarction: clinico-radiological correlations

Los infartos mesencefálicos suelen producir cuadros clínicos que permiten una localización precisade la lesión, aunque no siempre se ajustan a los patrones recogidos en los síndromes clásicos de la bibliografía, tal como ocurre en el caso que se presenta. Caso clínico. Mujer de 73 años sin factores de riesgo cardiovascular, que presentó un cuadrobrusco de inestabilidad, diplopía, ptosis palpebral e hipersomnia leve. En la exploración se observó la afectación del nervio oculomotor común derecho, la parálisis de la mirada vertical hacia arriba y hacia abajo, la dismetría de las extremidades derechasy la afectación piramidal leve de las extremidades izquierdas. En la resonancia magnética cerebral se objetivó un infarto tálamo-mesencefálico derecho en el territorio paramediano, que en el mesencéfalo superior se hacía bilateral. El estudio etiológico mostró únicamente una ateromatosis carotídea. Conclusiones. La afectación cerebelosa ipsilateral a la lesióndel nervio oculomotor común en los infartos mesencefálicos constituye una variante clínica muy infrecuente. La heterogeneidad patogénica de los infartos que afectan al mesencéfalo obliga a un estudio etiológico extenso. La resonancia magnética cerebral constituye una herramienta indispensable para comprender la clínica y las estructuras anatómicas implicadas en losinfartos cerebrales infrecuentes

Mesencephalic infarcts usually produce clinical features that allow the lesion to be located withprecision, although they do not always match the patterns included in the classical syndromes reported in the literature, as occurs in the case we describe here. Case report. We report the case of a 73-year-old female with no cardiovascular risk factors, who presented a sudden clinical picture of instability, diplopia, palpebral ptosis and mild hypersomnia. On examiningthe patient the following manifestations were observed: compromise of the right common oculomotor nerve, up and down vertical gaze palsy, dysmetry of the right limbs and mild long tract signs in the left limbs. Magnetic resonance imaging of the brain revealed right thalamo-mesencephalic infarction in the paramedian territory, which became bilateral in the uppermesencephalon. The aetiological study showed only a carotid atheromatosis. Conclusions. Cerebellar compromise ipsilateral to a lesion in the common oculomotor nerve in mesencephalic infarcts is a very uncommon clinical variant. The pathogeneticheterogeneity of infarctions involving the mesencephalon makes it necessary to carry out an extensive aetiological study. Magnetic resonance imaging of the brain is an essential tool for understanding the clinical picture and the anatomical structures involved in cases of infrequent cerebral infarction

Crisis mioclónicas inducidas por tramadol en paciente con epilepsia mioclónica juvenil / Myoclonic seizures induced by tramadol in patients with juvenile myoclonic epilepsy

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[Surgery of the subthalamic nucleus in Parkinson's disease]. / Cirugía del núcleo subtalámico en la enfermedad de Parkinson.

INTRODUCTION AND DEVELOPMENT: The subthalamic nucleus (STN) plays a crucial part in the pathophysiology of Parkinsonism. Its inactivation improves all the main signs and symptoms of Parkinson's disease. Surgery of the STN in patients with the disease is effective and the benefit/risk relationship very favorable. Although the dyskinesias are not a definite limitation, it seems most reasonable to use techniques of deep cerebral stimulation until greater experience has been obtained with subthalamotomy. The long term efficacy is being studied and preliminary data indicate that the clinical benefit obtained is maintained in the long term. CONCLUSIONS: More studies are necessary to determine the mechanism of action of surgery on the STN. The potential neuroprotector effect of subthalamic surgery requires more extensive study.

Cirugía del núcleo subtalámico en la enfermedad de Parkinson / Surgery of the subthalamic nucleus in Parkinson's disease

Introducción y desarrollo. El núcleo subtalámico (NST) desempeña un papel crucial en la fisiopatología del parkinsonismo. Su inactivación alivia todos los signos y síntomas cardinales de la enfermedad de Parkinson. La cirugía sobre el NST en pacientes con esta enfermedad es eficaz y la relación beneficio/riesgo es claramente favorable. Aunque las discinesias no constituyen una limitación definitiva, lo más razonable es utilizar las técnicas de estimulación cerebral profunda hasta que se disponga de una experiencia más extensa con la subtalamotomía. Se está analizando la eficacia a largo plazo y los datos preliminares indican que el beneficio clínico se mantiene con el paso del tiempo. Conclusiones. Deben realizarse más estudios para determinar el mecanismo de acción de la cirugía sobre el NST. El potencial efecto neuroprotector de la cirugía subtalámica debe investigarse con mayor profundidad (AU)

Marchiafava-Bignami disease with widespread extracallosal lesions and favourable course.

We report a 61-year-old alcoholic man who presented with subacute physical deterioration and severe dysarthria. MRI, suggestive of corpus callosum demyelination with associated white matter involvement in both cerebral hemispheres, indicated the diagnosis of Marchiafava-Bignami disease. During his stay in hospital the patient showed remarkable improvement, and was discharged 22 days after admission. On MRI 2 months later, the extracallosal lesions had disappeared. This case raises questions about some previous ideas on this disease, such as the prognosis of its acute forms and the significance of the extracallosal lesions seen on neuroimaging.

['Rubral' tremor after vascular thalamic lesions]. / Temblor 'rúbrico' tras lesiones vasculares talámicas.

INTRODUCTION: The appearance of tremor after thalamic lesions is well-known but infrequent. Amongst the semiological varieties of thalamic tremors, a particularly uncommon type--which is extremely incapacitating owing to its great amplitude, appearance during action and poor therapeutic response--is the so-called rubric or mesencephalic tremor. CLINICAL CASES: We present four cases, of tremor with the semiological characteristics of rubric tremors after thalamic lesions of ischaemic or haemorrhagic origin. We review the relevant literature. DISCUSSION: The rubric tremor has been said to have its physiopathological origin in a lesion of the nigro-striate via and the efferent cerebellar vias at some point of the mesencephalic or subthalamic path, often without direct involvement of the red nucleus. CONCLUSIONS: The presentation of this type of tremor due to lesions which do not effect the red nucleus and the mesencephalum show the unsuitability of the name.

[Spontaneous intravascular rupture of a giant neuroepithelial cyst]. / Rotura espontánea intraventricular de quiste neuroepitelial gigante.

We report the case of a woman presenting with a gait disorder. Magnetic resonance the brain showed a large parieto-neuroepithelial cyst. Surgery was ruled out and a new image taken nearly two years later showed the cyst cavity had collapsed spontaneously. The benign course of this type of lesion and the possibility of spontaneous recurrence suggest that a wait-and-see attitude can be chosen over surgery in patients with few clinical manifestations.