Studying nanoparticles' 3D shape by aspect maps: Determination of the morphology of bacterial magnetic nanoparticles.

Magnetic nanoparticles (MNPs) are widely investigated due to their potential use in various applications, ranging from electronics to biomedical devices. The magnetic properties of MNPs are strongly dependent on their size and shape (i.e., morphology), thus appropriate tools to investigate their morphology are fundamental to understand the physics of these systems. Recently a new approach to study nanoparticle morphology by Transmission Electron Microscopy (TEM) analysis has been proposed, introducing the so-called Aspect Maps (AMs). In this paper, a further evolution of the AM method is presented, allowing determination of the nanoparticles' 3D shape by TEM image. As a case study, this paper will focus on magnetite nanoparticles (Fe3O4), with a mean size of ∼45 nm extracted from Magnetospirillum gryphiswaldense magnetostatic bacteria (MTB). The proposed approach gives a complete description of the nanoparticles' morphology, allowing estimation of an average geometrical size and shape. In addition, preliminary investigation of the magnetic properties of MTB nanoparticles was performed, giving some insight into interparticle interactions and on the reversal mechanism of the magnetization.

Mucopolysaccharidosis: secondarily induced abnormal distribution of lysosomal isoenzymes.

Total activities of acid hydrolases in liver of two patients with mucopolysaccharidosis are decreased for beta-galactosidase, alpha-galactosidase, and arylsulfatase A; total activities of four other hydrolases are normal or increased. The isoenzyme distribution of five hydrolases (beta-glucuronidase, alpha-glucosidase, beta- galactosidase, N-acetyl-beta-glucosaminidase, and alpha-galactosidase) is ábnormal in that the isoelectric points (by isoelectric focusing) of these enzymes are more acid than in control liver. Along with the isoenzyme abnormalities different kinds of glycolipids were stored in kidney, liver, and brain. The isoenzyme abnormalities can be reproduced in vitro by addition of chondroitin sulfate to a homogenate of normal liver, suggesting that stable binding occurs between mucopolysaccharides and the hydrolase molecules. After the addition of chondroitin sulfate, the total activity of beta-galactosidase is inhibited, whereas other hydrolases are affected only slightly or not at all.

Configuration of the magnetosome chain: a natural magnetic nanoarchitecture.

Magnetospirillum gryphiswaldense is a microorganism with the ability to biomineralize magnetite nanoparticles, called magnetosomes, and arrange them into a chain that behaves like a magnetic compass. Rather than straight lines, magnetosome chains are slightly bent, as evidenced by electron cryotomography. Our experimental and theoretical results suggest that due to the competition between the magnetocrystalline and shape anisotropies, the effective magnetic moment of individual magnetosomes is tilted out of the [111] crystallographic easy axis of magnetite. This tilt does not affect the direction of the chain net magnetic moment, which remains along the [111] axis, but explains the arrangement of magnetosomes in helical-like shaped chains. Indeed, we demonstrate that the chain shape can be reproduced by considering an interplay between the magnetic dipolar interactions between magnetosomes, ruled by the orientation of the magnetosome magnetic moment, and a lipid/protein-based mechanism, modeled as an elastic recovery force exerted on the magnetosomes.

Normal pregnancy outcome in L-2-hydroxyglutaric aciduria.

L-2-Hydroxyglutaric aciduria (L-2-HGA) is a rare progressive neurometabolic disease, defined as a characteristic clinical and radiological entity, mainly including mental retardation, cerebellar dysfunction and involvement of the subcortical white matter, cerebellum and basal ganglia on brain MRI. The biochemical hallmark is an increased urinary excretion of L-2-hydroxyglutaric acid. Management is only supportive. A child born to a Turkish mother in whom L-2-HGA was previously diagnosed is reported. Although pregnancy was repeatedly advised against because of the important degree of mental retardation and the potential risk of a toxic effect on the embryo and/or fetus (at that time no reports of maternal L-2-HGA were available), she became pregnant at 30 years of age and the pregnancy passed uneventfully. On amniocentesis, performed at 5 months of gestational age, elevated 2-hydroxyglutarate, previously shown to be almost exclusively the L-2-stereoisomer, was present in the amniotic fluid: 27.5mu mol/L (controls <1.3; n=5). The child, not affected by the disease as shown by a normal urinary excretion of 2-hydroxyglutaric acid, was normal at birth. When last examined at the age of 3 years, both somatic and mental development were excellent. As the pathogenesis of the extensive brain damage in affected persons remains largely unknown, notwithstanding the recent identification of the mutated gene and the deficient enzyme, one can only speculate on the mechanism by which embryo and fetus from a L-2-HGA mother are spared, at least in this case.

Autosomal recessive inheritance of polymicrogyria and dermatomyositis with paracrystalline inclusions.

A 7-year-old mentally retarded girl died following subacute dermatomyositis. Muscle biopsies supported the clinical diagnosis and revealed paracrystalline inclusions on EM. The brain autopsy showed cerebral and cerebellar polymicrogyria. The clinico-pathological findings in this child are related to similar previously reported data in her older sister. The possibility of a new autosomal recessive syndrome involving both fetal brain development and childhood immunological function is discussed.

A case of fatal rotenone poisoning in a child.

A case of a fatal rotenone poisoning in a three-and-a-half-year-old girl is described. The case report and autopsy findings are mentioned. For the extraction of rotenone out of biological samples, a solvent partitioning and silica gel open column chromatographic cleanup procedure has been used. The determination of rotenone was performed by high pressure liquid chromatography.

Ophthalmological signs of tuberous sclerosis.

A patient with tuberous sclerosis and retinal astrocytic hamartomas is described. The different types of these astrocytomas are illustrated as well as systemic signs of Bourneville disease. Finally the value of the ophthalmological examination in the diagnostic work-up prior to genetic counselling the patient and/or the family members is discussed.

Successful liver transplantation for argininosuccinate lyase deficiency (ASLD).

Liver transplantation was performed in a girl with early-onset ASLD, leading to unrestricted protein intake and no further neurological deterioration.

Benign familial neonatal convulsions.

A male neonate presented with very frequent seizures, from the second day of life until the age of two weeks. Subsequently, convulsions did not recur. The patient, 7 years of age at present, has developed normally. Family history revealed transient neonatal convulsions in 8 other family members. The condition is inherited as an autosomal dominant trait.

Pulmonary vascular resistance rises with lung volume on exercise in obstructed airflow disease.

There has been experimental evidence that lung distension produces an increase in pulmonary vascular resistance (PVR). To study this effect in patients, we measured functional residual capacity (FRC) by helium dilution at rest and during low-load supine exercise in 30 patients with chronic obstructive pulmonary disease. Pulmonary haemodynamics were studied in these patients under the same conditions. FRC increased from rest (4.32 +/- 0.21 l) to exercise (4.71 +/- 0.20, P less than 0.001) but the change was smaller in the patients with the highest FRC at rest: there was a significant negative correlation between FRC change and FRC at rest (r = -0.38, P less than 0.01). There were seven patients with a small FRC change (less than 0.2 l) with exercise and 10 patients with a marked increase (greater than 0.5 l). Exercise was of the same load on average. FRC at rest was 5.1 l in the first group and 4 l in the second (P less than 0.05). Blood gases were almost identical at rest, and almost unchanged during exercise. PVR decreased from rest to exercise by 33 dyn.s.cm-5 in the first group and increased by 24 in the second (P less than 0.01). There was a significant correlation (P less than 0.05) between PVR and FRC changes from rest to exercise. These results suggest that lung distension may play a role in the PVR increase seen in some COPD patients with exercise.

Acute tubulo-interstitial nephritis and uveitis syndrome (TINU syndrome).

Acute renal failure due to tubulo-interstitial nephritis developed in a 15-year-old girl. The disease was accompanied by uveitis and an inflammatory syndrome, consisting of a markedly increased erythrocyte sedimentation rate and high serum gamma globulin levels. The nephropathy as well as the inflammatory syndrome subsided spontaneously. A topical antiphlogistic treatment healed the ocular disease, which has not relapsed so far. The association of acute tubulo-interstitial nephritis and acute uveitis observed in several patients has led to the identification of a specific syndrome with a very particular symptomatology and course, the so-called TINU syndrome, the interest of which resides in the predictability of the complete reversibility of the nephropathy either spontaneously or after steroid treatment, contrasting with the marked tendency towards relapse of the uveitis. The demonstration of circulating immune complexes in the serum during the acute phase of the illness, as in our patient, further points to the involvement of immune processes in the syndrome, but the origin and pathogenesis remain as yet unknown.

[Infection by avian chlamydiosis in breeding pigeons in New Caledonia]. / Infection par la chlamydiose aviaire chez les pigeons d'élevage en Nouvelle-Calédonie.

An epidemiological survey on avian chlamydiosis, carried out by serological probing in 8 pigeon breeders representative of New Caledonian livestock, combined with bacteriological research on pigeon organs and droppings was set up in New Caledonia in order to determine the prevalence rate of this infection and to adapt sanitary regulations concerning pigeon imports. All sera collected (230) were analysed by complement fixation test (CFT). The organs were diluted in sucrose solution, then stored frozen (-70 degrees C), until inoculation of the yolk-sac of 3 6-8-day-old embryonated eggs (2 blind passages). Yolk-sac smears stained according to the Gimenez method were made in order to detect intracellular chlamydial organisms. Seventeen sera out of 230 were found to be positive, ie 7.4% of the test sample (confidence interval to 95% = 4.0 to 10.8%). The carrier pigeons were significantly more infected (17.8%) than pigeons of other breeds in New Caledonia. These results resulted in the sanitary authorities easing restrictions on imports of seropositive pigeons by imposing a 45-day compulsory quarantine with daily administration of chlortetracycline at the rate of 150 mg per 1 of drinking water.

Endoscopic treatment of suprasellar arachnoid cysts.

Four cases of large suprasellar arachnoid cysts in children are described. The authors propose a large fenestration into the lateral ventricles and into the basal cisterns as the treatment of choice. A specific multipurpose cerebral endoscope has been designed by the first author. The endoscopic technique with different instruments and with the use of a laser is illustrated. Results and complications are discussed.

Lyme borreliosis--a review of the late stages and treatment of four cases.

Difficulties in diagnosis of late stages of Lyme disease include low sensitivity of serological testing and late inclusion of Lyme disease in the differential diagnosis. Longer treatment modalities may have to be considered in order to improve clinical outcome of late disease stages. These difficulties clinical cases of Lyme borreliosis. The different clinical cases illustrate several aspects of late borreliosis: false negative serology due to narrow antigen composition of the used ELISA format, the need for prolonged antibiotic treatment in chronic or recurrent forms and typical presentations of late Lyme disease, such as lymphocytic meningo-encephalitis and polyradiculoneuritis.

Lyme disease in a child presenting with bilateral facial nerve palsy: MRI findings and review of the literature.

We report a 7-year-old boy with neuroborreliosis presenting with headache and bilateral facial nerve palsy. MRI demonstrated tentorial and bilateral facial and trigeminal nerve enhancement.

Complete genomic structure and mutational spectrum of PHKA2 in patients with x-linked liver glycogenosis type I and II.

X-linked liver glycogenosis (XLG) is probably the most frequent glycogen-storage disease. XLG can be divided into two subtypes: XLG I, with a deficiency in phosphorylase kinase (PHK) activity in peripheral blood cells and liver; and XLG II, with normal in vitro PHK activity in peripheral blood cells and with variable activity in liver. Both types of XLG are caused by mutations in the same gene, PHKA2, that encodes the regulatory alpha subunit of PHK. To facilitate mutation analysis in PHKA2, we determined its genomic structure. The gene consists of 33 exons, spanning >/=65 kb. By SSCP analysis of the different PHKA2 exons, we identified five new XLG I mutations, one new XLG II mutation, and one mutation present in both a patient with XLG I and a patient with XLG II, bringing the total to 19 XLG I and 12 XLG II mutations. Most XLG I mutations probably lead to truncation or disruption of the PHKA2 protein. In contrast, all XLG II mutations are missense mutations or small in-frame deletions and insertions. These results suggest that the biochemical differences between XLG I and XLG II might be due to the different nature of the disease-causing mutations in PHKA2. XLG I mutations may lead to absence of the alpha subunit, which causes an unstable PHK holoenzyme and deficient enzyme activity, whereas XLG II mutations may lead to in vivo deregulation of PHK, which might be difficult to demonstrate in vitro.