All-electric quantum point contact spin-polarizer.

The controlled creation, manipulation and detection of spin-polarized currents by purely electrical means remains a central challenge of spintronics. Efforts to meet this challenge by exploiting the coupling of the electron orbital motion to its spin, in particular Rashba spin-orbit coupling, have so far been unsuccessful. Recently, it has been shown theoretically that the confining potential of a small current-carrying wire with high intrinsic spin-orbit coupling leads to the accumulation of opposite spins at opposite edges of the wire, though not to a spin-polarized current. Here, we present experimental evidence that a quantum point contact -- a short wire -- made from a semiconductor with high intrinsic spin-orbit coupling can generate a completely spin-polarized current when its lateral confinement is made highly asymmetric. By avoiding the use of ferromagnetic contacts or external magnetic fields, such quantum point contacts may make feasible the development of a variety of semiconductor spintronic devices.

A comparative study of the peak expiratory flow rate of Indian and Nepalese young adults in a teaching institute.

Peak expiratory flow rate (PEFR) measurement is the easiest and cheapest method to evaluate respiratory functions. So, the study was carried out to evaluate PEFR of healthy Nepalese adults and compare their values with healthy Indian counterparts to know whether Indian prediction equations for PEFR can be used for Nepalese adult population or not. One hundred twenty-three healthy, young, non smoker adult Indian (64: 28 Males, 36 Females) and Nepalese (59: 32 Males, 27 Females) medical students of 18 to 20 years of age participated in the study. The mean PEFR of Indian (male: 490.4 liter/min, female: 386.0 liter/min) and Nepalese (male: 485.9 liter/min, Female: 365.2 liter/min) young adults were found to have no significant differences. As there is no significant difference in the mean PEFR of Indian and Nepalese young adults, prediction equations made for Indian adults can be used to predict PEFR of Nepalese subjects. Therefore, an attempt has been made to formulate a regression equation from the combined Indian and Nepalese subjects. A stepwise, multiple, linear, regression analysis was performed for this purpose. The analysis showed that height is the best predictor for PEFR in the present study. The regression equation based on height for the combined Indian and Nepalese young adults is calculated as: PEFR = 5.687 x Height (cm) - 495.787. However, a stepwise, multiple, linear, regression equation with residual analysis for the best fit model was performed to formulate prediction equation for PEFR and this showed a change of the earlier regression equation to PEFR = 5.930 x Height (cm) - 536.131.

Role of viruses and atypical bacteria in exacerbations of asthma in hospitalized children: a prospective study in the Nord-Pas de Calais region (France).

We studied the role of viruses and atypical bacteria in children hospitalized with exacerbated asthma by a prospective study of children with acute asthma admitted to the Department of Pediatrics in Lille, and to 15 hospitals in the Nord-Pas de Calais region, from October 1, 1998-June 30, 1999. We included children aged 2-16 years with active asthma, defined as three or more recurrent episodes of reversible wheezing. The severity of asthma and of asthmatic exacerbations was recorded. Immunofluorescence assays (IFA) on nasopharyngeal secretions (NPS), serological tests, or both, were used for detection of influenza virus, respiratory syncytial virus (RSV), adenovirus, parainfluenza virus, and coronavirus. Polymerase chain reaction (PCR) assays on NPS were used for rhinovirus and enterovirus. Serological tests for Chlamydia pneumoniae and Mycoplasma pneumoniae were performed. A control group of asymptomatic asthmatic outpatients was examined for respiratory viruses (using IFA and PCR). Eighty-two symptomatic children (mean age, 7.9 years) were examined. Viruses were detected in 38% (enterovirus, 15.8%; rhinovirus, 12%; RSV, 7.3%). Serological tests for atypical bacteria were positive in 10% of patients (C. pneumoniae, 5%; M. pneumoniae, 5%). Among the 27 control subjects (mean age, 7.9 years), one PCR was positive for enterovirus. There was no correlation between severity of chronic asthma or asthmatic exacerbations and the diagnosis of infection. Atypical bacterial pathogen infections were linked with prolonged asthmatic symptoms. In conclusion, we confirmed the high incidence of viral infection in acute exacerbations of asthma, especially enteroviruses or rhinoviruses. Persistent clinical features were more frequently associated with atypical bacterial infections, suggesting that these infections should be investigated and treated in cases of persistent asthmatic symptoms.

[Brain abscess complicating dental caries in children]. / Abcès cérébraux de l'enfant compliquant des caries dentaires.

Brain abscess following dental or periapical infection is rare in childhood. This report describes brain abscesses found in two children with dental caries. Case 1.--A 12 year-old boy was admitted because he had suffered from acute meningitis for 3 days. Clinical examination showed symptoms of meningitis plus palsy of the right third and fourth cranial nerves and of the left facial nerve, and a defect in the left temporal field. Funduscopic examination showed papilledema; CT scan and MRI showed a ring-shaped lesion in the right occipital area. The patient was given cefotaxime and thiamphenicol. The abscess was drained; bacteriological examination showed Actinomyces viscosus and Peptostreptococcus magnus. The neurological condition and the CT scan lesion improved, but intracranial pressure increased again on the 17th day after the onset, requiring replacement of the antibiotics by rifampicin and ampicillin plus clavulanic acid for 2 months. This brain abscess appeared to be metastatic, derived from the infection of a large dental cyst due to a dental infection that had been treated 6 months earlier. Case 2.--A 8 1/2 year-old girl was admitted because she was suffering from palsy of the left facial nerve and left arm. She had had headaches and fever for a few days. Clinical examination showed the palsies and drowsiness. CT scan showed two brain abscesses. The patient was given ceftriaxone, fosfocin and metronidazole. She had been treated for a gingival abscess 1 month earlier, and had two infected teeth extracted. Improvement of the intracranial pressure was transient and the antibiotics were changed on the 12th day of treatment.(ABSTRACT TRUNCATED AT 250 WORDS)

[Chondrodysplasia with macrocranium and mental retardation in 2 brothers]. / Chondrodysplasie avec macrocranie et retard mental chez deux frères.

Two cases of a very unusual bone dysplasia in two brothers are reported. Features included very severe dwarfism, with macrocrania and mental deficiency. Roentgenograms taken in early infancy were reminiscent of spondyloepiphyseal dysplasia congenital syndrome but the course was not suggestive of this diagnosis. The shafts of the long bones became increasingly narrow, whereas the metaphyses broadened and the epiphyses at the knee became extremely wide. Vertebral bodies were ovoid or trapezoidal. The skull was extremely large. Since two offspring of consanguineous parents were involved, this disease is certainly of genetic origin. Autosomal recessive transmission is likely, although X-linked transmission cannot be outruled.

[Pseudohypoaldosteronism: familial forms. Eight case-reports, with a review of the literature (author's transl)]. / Pseudo-hypoaldostéronisme: formes familiales. A propos de huit cas et revue de la littérature.

Pseudohypoaldosteronism (PHA) is an uncommon cause of the renal salt loosing syndrome in infancy. The authors describe eight cases in two different families. Hyperaldosteronism persists long after clinical recovery has occurred. Plasma hormone assay allows retrospective recognition of cases overlooked during infancy. This underlines the variability of disease expression among different members of the same family. The high family occurrence rate (over 50%), which is often underestimated, is demonstrated by the study of both families and by a review of published cases. Clinical and biochemical features of familial PHA are discussed. Inheritance is usually on an autosomal dominant basis. However, the small number of reported cases cannot allow any attempt to individualize subgroups of the disorder upon genetic grounds.

[A case of trisomy 19 mosaicism (author's transl)]. / Sur un cas de trisomie 19 en mosaïque.

Trisomy-19 mosaicism was observed in lymphocytes of a newborn male with facial dysmorphism (upward slanting palpebral fissures, pointed nose, short upper lip, prominent antitragus), laryngeal stridor, and leucothrombopenia, and who died on day 13. Autopsy revealed no other major malformation but poor development of the cerebral sulci.

[Severe blood coagulation disorder as the first sign of a peritoneal hemangio-endothelioma: a new therapeutic approach (author's transl)]. / Perturbations sévères de l'hémostase révélant abord thérapeutique.

The authors describe a 3 1/2 month old infant with hemangio-endothelioma and a severe blood coagulation disorder. The tumor was inoperable and the severe blood coagulation disorder posed considerable therapeutic problem. After treatment with massive amounts of blood clotting factors, an antifibrinolytic drug and radiotherapy, the child's condition improved.