On morphology and strain field of Ge/Si(001) Islands according to TEM phase imaging method.

The mechanism driving Germanium islands nucleation and self-assembly is an important effect for opto-electronic applications, still not fully understood. We demonstrate that the new transmission electron microscopy phase imaging method provides insights on the distribution of strain and composition fields in and around the islands on rather large areas. The method consists of retrieving the phase from a focus series of plane view images. The phase image is representative of morphology, composition and strain. The results show that whatever the islands size and shape is, a maximum compressive strain is obtained at the apex of the islands compensated by a maximum tensile strain in the substrate close to the islands perimeter. The maximum compressive strain is associated to a larger Ge concentration. The distribution of tensile strain varies with the shape of the islands: for square base pyramidal "hut" islands, a maximum tensile strain is obtained at the four corners of the pyramid base and for "dome" islands, the tensile strain is less pronounced and affects almost the whole island perimeter. These results are consistent with the higher strain relaxation level of "dome" islands in comparison to those of "hut" islands.

Imaging a dense nanodot assembly by phase retrieval from TEM images.

Phase retrieval is a classical inverse problem in many fields dealing with waves that is becoming of increasing interest in transmission electron microscopy (TEM). A non-interferometric approach is here applied to TEM images. Phase retrieval possibilities given by the transport intensity equation are compared to the ones deriving from the weak phase object approximation. In the limit of small angles, both methods lead to a similar equation between the phase and a set of defocus images. This equation can be solved by an image processing equivalent to using a specific filter in Fourier space. This processing leads to phase images with a spatial resolution here essentially limited by the defocus amount between images. A dense assembly of silicon nanodots is used as a model case to illustrate the interest of this approximate phase retrieval method which can be carried out on standard equipment. The dot heights estimated using the phase images are found to be in good agreement with ones measured by atomic force microscopy. Since image noise and large defocus values may strongly affect the solution given by the approximate method, an iterative phase retrieval method is also used as a test for working conditions.

[Renal involvement in POEMS syndrome]. / Atteinte rénale au cours du syndrome POEMS.

We described a patient with a POEMS syndrome (Polyneuropathy, Organomegaly, Endocrinopathy, Monoclonal grammapathy and Skin changes) who was found to have renal involvement with peculiar renal pathological findings. Hitherto, 17 other cases, most of them from Japan, of POEMS syndrome with renal involvement, have been published. Clinical features are variable: acute renal failure with anasarca or moderate chronic renal insufficiency with mild proteinuria. This latter presentation often passes unnoticed. There is no severe HTA, no microangiopathic hemolytic anemia. Renal biopsy shows prominent glomerular changes which are unusual and distinct from membranoproliferative glomerulonephritis (MPGN) and from glomerular thrombotic microangiopathy (TMA). Mesangial proliferation and thickening of the capillary wall with double contour evoke by light microscopy a MPGN. By immunofluorescent microscopy, no immunoglobulins or complement deposits are found. The finding of mesangiolytic lesions has led to the term of "mesangiolytic glomerulonephritis". The presence, on electron microscopy, of lucent subendothelial space could evoke TMA. But there is neither thrombi, nor arteriolar changes. We are inclined to presume that microangiopathic lesions are due to chronic injury of glomerular endothelial cells, exacerbated at outbreaks of the disease. An increased production of IL-6 could support the efficacity of corticosteroid therapy, particularly in acute clinical situations.

[Voluntary poisoning by Cortinarius orellanus: usefulness of an original early treatment after determination of orellanine in the biological fluids and tissues]. / Intoxication volontaire par Cortinarius orellanus: intérêt d'un traitement précoce original après dosage de l'orellanine dans les milieux biologiques et tissulaires.

Cortinarius poisoning is generally caused by orellanine, a hydroxy bipyridine N, N-dioxide. This intoxication is characterized by acute nephritis which can lead to death without treatment. We reported a highly sensitive and simple fluorimetric technique to analyse orellanine by thin-layer chromatography on the basis of its characteristic photodecomposition into orelline. Using this procedure, we detected and assayed orellanine for the first time in plasma and renal biopsies of a woman who had deliberately ingested two fruit-bodies of Cortinarius orellanus. An early original treatment was carried out based on hemodialysis, combination plasmapheresis-hemoperfusion, and amino acids and diltiazem administration. These results indicate that it is now possible to make a precise diagnosis of orellanine poisoning.

Recombinant human erythropoietin: 18 months' experience in hemodialysis patients.

It has been shown that the regular administration of erythropoietin (EPO) permits the correction of anemia in end-stage renal failure patients. We analyzed the effect of chronic administration of EPO in 13 stable, regularly dialyzed end-stage renal failure patients over an 18-month period. The effects of EPO were evaluated according to standard criteria including clinical status, blood pressure control, hematology and biochemistry data, protein nutritional status, and dialysis efficiency. Following a 2-week control period, EPO was administered intravenously (IV) after the dialysis session according to a two-phase protocol. The first period (correction phase) consisted of a stepwise EPO dose increment, starting at 3 x 24 IU/kg/wk and doubling the dose every 14 days according to hemoglobin response in order to achieve a target hemoglobin level of approximately 11.0 g/dL (110 g/L). In the second period (maintenance phase) EPO dose was optimized to maintain the hemoglobin level between 100 and 110 g/L (10.0 and 11.0 g/dL), by adjusting either the unit dose or the frequency of injection. Anemia was corrected in all patients within 11 weeks, with EPO dose increasing from 72 to 360 IU/kg/wk. The stabilization of hemoglobin was achieved with an average EPO dose of 275 IU/kg/wk (50 to 476 IU/kg/wk). Concomitantly, a subjective and clinical improvement was noted in all patients. The dialysis efficacy remained in an acceptable range throughout the study, falling significantly (approximately 10%) through the first 3 months of treatment to stabilize at an effective urea clearance of approximately 120 L/wk. The dietary protein intake calculated from urea kinetic modeling ranged between 1.1 and 1.2 g/kg/d.(ABSTRACT TRUNCATED AT 250 WORDS)

[Recombinant human erythropoietin: 18 months of continuous use in substitution hemodialysis]. / Erythropoïétine humaine recombinante: 18 mois d'utilisation continue en hémodialyse de suppléance.

It has been shown that the regular administration of EPO permits the correction of anemia in end stage renal failure patients. We analyzed the effect of chronic administration of EPO in 13 stable, regularly-dialysed end stage renal failure patients over an 18 month period. The effects of EPO were evaluated according to standard criteria including clinical status, blood pressure control, hematology and biochemistry data, protein nutritional status and dialysis efficiency. Following a 2 week control period, EPO was administered intravenously after the dialysis session according to a 2 phase protocol. The first period (correction phase) consisted of a stepwise EPO dose increment, starting at 24 IU/kg x 3 times and doubling the dose every 14 days according to hemoglobin response in order to achieve a target hemoglobin level of 11 g/dl. In the second period (maintenance phase) EPO dose was optimized to maintain the hemoglobin level between 10 and 11 g/dl, by adjusting either the dose or the frequency of injection. Anemia was corrected in all patients within 10 weeks with EPO dose increasing from 72 to 360 IU/kg/week. The stabilisation of hemoglobin was achieved with an average EPO dose of 275 IU/kg/week (50 to 476 IU/kg/week). Concomitantly, a subjective and clinical improvement was noted in all patients. The dialysis efficacy, although remaining in an acceptable range, fell significantly by 10% over the first 3 months of treatment, remaining stable afterwards, yielding an effective urea clearance near to 120 1/week. The dietary protein intake calculated from urea kinetic modelling ranged between 1.1 and 1.2 g/kg/day.(ABSTRACT TRUNCATED AT 250 WORDS)

[Outcome of acute renal failure caused by voluntary ingestion of Cortinarius orellanus]. / Evolution d'une insuffisance rénale aiguë par ingestion volontaire de Cortinarius orellanus.

Orellanin poisoning is characterized by an acute renal failure which can be lethal if the appropriate treatment is not given. A 31-year old woman was admitted to hospital 10 days after she had deliberately ingested 2 raw carpophores of the mushroom Cortinarius orellanus. Acute renal failure (creatininaemia 1,100 mumol/l) developed, requiring 6 sessions of haemodialysis, one of plasmapheresis and the administration of diltiazem and aminoacids. Plasma and tissue assays of orellanin, the mushroom's toxin, were performed by two-dimensional thin layer chromatography. Before haemodialysis and 10 days after ingestion of the poison, the plasma contained orellanin. Eighteen months after the attempted suicide, the plasma creatinine level was 181 mumol/l.