Temperature-dependent transport properties of CVD-fabricated n-GaN nanorods/p-Si heterojunction devices

We report on the structural, electrical, and transport properties of high quality CVD-fabricated n-GaN nanorods (NRs)/p-Si heterojunction diodes.

Stroke and syphilis: A retrospective study of 53 patients

OBJECTIVE

The aim of this study was to describe the clinical, biological and radiological characteristics of patients with syphilitic vasculitis, and to assess the outcome after treatment.

METHODOLOGY

A retrospective review was carried out based on the records of patients with ischemic stroke, and reactive CSF TPHA and VDRL results. None of these patients showed symptoms of any other diseases or had received high doses of penicillin.

RESULTS

A total of 53 patients with stroke met the diagnostic criteria for syphilitic arteritis. Their average age was 41±12 years. Nine patients had a history of genital ulcer (17%), and the median duration of illness after presenting a chancre was 8 [range: 1-14] years. A prodromal syndrome was seen in 27 patients (50.9%) and included changes in mental status in 14 patients (26.4%), seizures in 10 cases (18.9%), headache in eight (15.1%) and memory loss in seven (13.2%). Neurological events included focal motor deficits in 29 cases (54.7%), ataxia in 11 (20.8%) and movement disorders in 15 (28.3%). HIV serology was performed in 31 patients and proved negative in every case. Disease evolution was generally favorable: 12 patients (22.6%) were autonomous at the time of hospital discharge; 29 (54.7%) had partially recovered; and only seven (13.2%) still had signs of severe sequelae.

CONCLUSION

A diagnosis of syphilitic stroke should be suspected in young patients as a manifestation of syphilis, and tests for neurosyphilis should be routine in neurology departments to make a prompt diagnosis, thereby preventing psychological sequelae.

A clinical study of non-parkinsonian tremor in Moroccan patients

OBJECTIVE

To report the characteristics of the most frequent tremors in a population of Moroccan patients.

BACKGROUND

Tremor is the most common movement disorder. It implies a wide variety of disorders with Parkinson's disease and essential tremor being the most frequent.

METHODS

A retrospective study of 148 patients with tremor referred to our movement disorders outpatient clinic was performed. Clinical features and treatment regimens were analyzed. Patients with parkinsonian tremor were excluded.

RESULTS

We included 62 patients with non-parkinsonian tremor. The etiologies were as follows: essential tremor (54.8%), dystonic tremor (19.4%), tremor associated with dystonia (14.5%), enhanced physiological tremor (3.2%), cerebellar tremor (3.2%), psychogenic tremor (3.2%) and Holmes' tremor (1.6%). The characteristics of essential tremor patients were analyzed. Female patients accounted for 67.6% of patients. Mean age at the onset of tremor was 52.2 ± 16.4 years. Family history of tremor was reported in 17.6% of cases. Tremor affected the arms (94.1%), head (52.9%), voice (35.3%) and legs (8.8%). Tremor was bilateral in 87.5% but was asymmetrical in 50% of patients. Patients had postural tremor (76.5%), kinetic tremor (79.4%) and rest tremor (associated in 11.8%). Treatment relied on propranolol (88.3%), primidone (14.7%), gabapentin (14.7%), clonazepam (14.7%), alprazolam (11.8%), topiramate (5.9%) and, in one patient, radiosurgery.

CONCLUSIONS

Essential tremor was the predominant diagnosis, confirming its high prevalence. There was a predominance of female patients and a peak of age at onset in the fifth and sixth decades. Asymmetry of the disease was noted in half of patients.

The influence of phosphorus content on magnetic anisotropy in ferromagnetic (Ga, Mn) (As, P)/GaAs thin films

The magnetic anisotropy of the ferromagnetic semiconductor (Ga, Mn) (As, P) is studied in a material-specific microscopic k ⋅p approach. We calculate the electronic energy band structure of (Ga, Mn) (As, P) quaternary ferromagnetic alloys using a 40-band k ⋅p model and taking into account the s, p-d exchange interaction and the strain of the (Ga, Mn) (As, P) layer on a GaAs substrate. We determine the variations of the carrier effective masses in the strained (Ga, Mn) (As, P)/GaAs system. The magnetic anisotropy constants obtained from our simulations using a mean-field model are compared with the experimental ones determined by ferromagnetic resonance spectroscopy on a set of samples with constant manganese concentration and varying phosphorus concentration. An excellent quantitative agreement between experiment and theory is found for the uniaxial out-of-plane and cubic in-plane anisotropy parameters.

Profile of multiple system atrophy in Moroccan patients attending a movement disorders outpatient clinic in Rabat university hospital

INTRODUCTION

Multiple system atrophy (MSA) is a sporadic and rapidly progressive neurodegenerative disorder of poor prognosis, characterised clinically by any combination of parkinsonian, autonomic, cerebellar, or pyramidal signs. We report our experience in movement disorders consultation concerning the clinical presentation and the course of MSA in Moroccan patients.

METHODS

A retrospective review of the medical records of 17 patients with diagnosis of MSA seen in our outpatient clinic from January 2007 to December 2010.

RESULTS

In our 17 patients, 76.5% were men and the mean age of onset was 52±9 years. MSA-P was the major clinical phenotype (82.4%). Eleven patients (64.7%) were classified as having probable MSA and six patients (35.3%) as possible MSA. Dysautonomic features were detected in all patients; urinary symptoms were found in 76.5% of cases and orthostatic hypotension in 64.7%. Treatment regimen included l-Dopa with a mean daily dose of 621.4±346.8mg/day and symptomatic treatment of dysautonomia. The mean duration of disease evolution was of 4.7±1.9 years.

DISCUSSION

Our results show a male predominance and an early age of disease onset. MSA-P was the predominant subtype. Our results are similar to the European MSA series.

CONCLUSION

Multicentre studies are needed to better characterise MSA in Morocco given the rarity of this disease.

[Psychotic disorder revealing epilepsy linked to a dysembryoma of the left hippocampus]

INTRODUCTION

Psychotic symptoms are a rare but well-known complication of epilepsy. The prevalence is estimated between 4 and 9%.

PATIENT

We report a case of a 40-year-old patient, unrecognized epileptic, who presented an acute psychotic syndrome which seemed to be of functional origin, the EEG performed during the episode, and the cerebral CT scan being normal. Nevertheless, the clinical presentation, especially the sudden ending of delusions, led to further investigations. Careful history taking and repeated EEG recordings allowed the diagnosis of partial epilepsy that had begun 17 years earlier and symptomatic of a dysembryoplastic tumour of the left hippocampus revealed by MRI.

DISCUSSION AND CONCLUSION

Search for an epileptic origin of an acute psychotic syndrome must always be undertaken by systematic EEG. The possibility of a symptomatic temporal tumor must not be overlooked.

[Interest of corticosteroids in neurological complications of celiac disease]

INTRODUCTION

Neurological manifestations of celiac disease are rare and polymorphic. Similar to lesions of the digestive tract, the standard treatment includes steroids.

CASE REPORT

A 41-year-old woman, followed up for celiac disease resistant to gluten-free diet, developed rapidly spastic paraparesis, cerebellar syndrome, horizontal diplopia and decline of visual acuity. The diagnosis of neurological complications of celiac disease was established and the patient was treated with methylprednisolone, followed by oral prednisone. For 9 years, the patient's neurological status remained stabilized with a prednisone dose at 20mg per day. The patient relapsed when progressive reduction of prednisone dose was attempted; neurological and gastrointestinal signs worsening at 15mg per day; increasing the dose to 30mg improved the clinical status.

DISCUSSION

The mechanism of onset of neurological disease remains unknown. Immunological, nutritional, toxic or metabolic factors could be involved. The positive response to corticosteroids observed in this patient suggest an immunological mechanism.

[Pachymeningitis associated with probable Horton's disease: a case report]

INTRODUCTION

Horton's disease is the most common vasculitis of elder people. Several neurological complications are reported, but pachymeningitis is exceptional.

OBSERVATION

A 71-year-old patient who presented headache, hyperesthesia of the scalp, weight loss with a biological inflammatory syndrome and meningeal thickening on MRI. The diagnosis of pachymeningitis related to Horton's disease was retained. The patient was treated by corticosteroids with a good clinical, biological and radiological course after 22 months.

CONCLUSION

Horton's disease is a potential diagnosis in elderly persons with pachymeningitis and inflammatory syndrome.