Steroid hormones in systemic sclerosis: associations with disease characteristics and modifications during scleroderma renal crisis.

OBJECTIVE: The renin-angiotensin-aldosterone system (RAAS) and glucocorticoids (GCs) are involved in vascular remodeling and fibrosis, but have not been extensively studied in systemic sclerosis (SSc). Our aim was to investigate the RAAS and GC hormones in SSc patients. METHODS: Serum levels of renin (dosage and activity), aldosterone and its precursors (DOC, B, 18-OH-DOC, 18-OH-B), and GCs (cortisol, cortisone, 11-deoxycortisol, 18-OH-F) were assessed in 122 SSc patients and 52 healthy controls. After applying stringent inclusion criteria aimed at ensuring accurate hormone assessments (exclusion of interfering drugs, strict sampling conditions), we analyzed RAAS hormones in 61 patients, and GCs in 96 patients. Hormone levels were compared between patients and controls; and associations with disease characteristics were assessed in patients. RESULTS: Regarding RAAS hormones, SSc patients displayed significantly lower aldosterone levels (although within normal range), similar renin levels, and higher B levels than controls. Abnormal RAAS hormone levels were associated with a more severe SSc phenotype (lung and skin fibrosis, heart and pulmonary vascular involvements, inflammation). Regarding GC hormones, SSc patients had higher levels of cortisol, 11-desoxycortisol (precursor) and 18-OH-F (metabolite) but lower levels of cortisone (inactive counterpart) than controls.RAAS hormone levels were assessed in 5 SSc patients before and during scleroderma renal crisis (SRC): concentrations varied considerably between patients, but consistently included normal/increased aldosterone levels and elevated renin levels. CONCLUSION: RAAS and GC hormones are abnormally produced in SSc patients, especially in patients with severe SSc and during SRC. This could suggest a participation of these hormonal systems in SSc pathogenesis.

Temperature, geometry, and bifurcations in the numerical modeling of the cardiac mechano-electric feedback.

This article characterizes the cardiac autonomous electrical activity induced by the mechanical deformations in the cardiac tissue through the mechano-electric feedback. A simplified and qualitative model is used to describe the system and we also account for temperature effects. The analysis emphasizes a very rich dynamics for the system, with periodic solutions, alternans, chaotic behaviors, etc. The possibility of self-sustained oscillations is analyzed in detail, particularly in terms of the values of important parameters such as the dimension of the system and the importance of the stretch-activated currents. It is also shown that high temperatures notably increase the parameter ranges for which self-sustained oscillations are observed and that several attractors can appear, depending on the location of the initial excitation of the system. Finally, the instability mechanisms by which the periodic solutions are destabilized have been studied by a Floquet analysis, which has revealed period-doubling phenomena and transient intermittencies.

A reactive transport model designed to predict the environmental footprint of an 'in-situ recovery' uranium exploitation.

Worldwide, most uranium production relies on the 'in situ recovery' (ISR) extraction technique. This consists of dissolving the ore using a leaching solution (acid or alkaline) directly within the deposit through a series of injection and extraction wells. Due to the nature of the injected ISR solutions, the water quality of the aquifer could be affected. Reactive transport modeling is a powerful tool for predicting fluid flow and geochemical reactions in ISR reservoirs. In this study we present a coupled 3D environmental geochemical model (EGM) (based on the HYTEC reactive transport software), capable of predicting the physico-chemical conditions in an acid-leaching ISR uranium mine and its environmental footprint on the aquifer in the years following the closure of the production block. The model was validated at the KATCO mine (Kazakhstan) on two different and independent production blocks, over 10 years after their closure. The model shows that incorporating two main geochemical processes, (1) cationic sorption on clay surfaces (smectite-beidellite) and (2) precipitation of gypsum (CaSO4.2H2O), successfully reproduces the measured well data (pH, acidity and SO4) over short- and long-term time scales. Clay surface sites remain mostly saturated in protons during the production phase. Simulations show that sorbed protons on the clay surfaces maintains the acid conditions for a longer period of time. The environmental impact model was also compared to a pre-existing model specifically developed for production simulation purposes: differences are observed as expected for the uranium production, but also for the impact distances, due to differences in the considered reactive mineralogical paragenesis. Thus, the choice of geochemical model should be made with due regard for the desired objectives. This work will assist the mine operator by providing a tool capable of assessing both the short- and long-term environmental footprints of the ISR production operation conditions and of identifying the best remediation strategy.

OPHDIAT: quality-assurance programme plan and performance of the network.

AIMS: There is a need for evaluation of screening and grading services for diabetic retinopathy (DR) in compliance with quality-assurance (QA) standards. We describe the screening/grading QA programme set up for OPHDIAT over the 2005-2006 period. METHODS: Screening and grading objectives, evaluation criteria and minimum acceptable QA standards were set. To ensure the quality of DR photos, the proportion of nongradable photos in at least one eye had to be less than 10%. To ensure grading accuracy, intergrading agreement had to be greater than 90%. Grader-generated reports had to be available in less than 48 h for more than 80% photos. Readers had to grade 500 to 3000 photos per year. RESULTS: Sixteen screening centres were opened between June 2004 and December 2006, and 14,769 patients were screened. Percentages of nongradable photos were consistently below the QA requirement (less than 10%). Overall, 800 photos were graded a second time by a reader blinded to original grading; agreement between graders ranged from 92 to 99%. More than 90% of grader-generated reports were produced within 48 h. The number of readings by each grader nearly achieved the QA standard. CONCLUSION: QA for DR telescreening should be a continuous process to provide performance feedback, thus guaranteeing a high standard for delivered results. Almost all of the predetermined QA standards in OPHDIAT for screening and grading were met. Besides the quality/sensitivity of the screening/grading modalities, it is important to evaluate at-risk patients so that they can be treated efficiently; this should be addressed in a global QA programme.

OPHDIAT: a telemedical network screening system for diabetic retinopathy in the Ile-de-France.

OBJECTIVE: International and national guidelines recommend an annual funduscopic examination for all diabetic patients, but such annual fundus examinations are not sufficiently performed in France. Non-mydriatic fundus photography is a valid method of evaluation for diabetic retinopathy (DR) and a viable alternative to ophthalmoscopy. After two pilot studies demonstrated the feasibility of telemedical screening for diabetic retinopathy in both hospital and primary-care settings, we developed a regional telemedical network, OPHDIAT, designed to facilitate access to regular annual evaluations of patients with diabetes while saving medical time. MATERIALS AND METHODS: OPHDIAT comprises peripheral screening centres equipped with non-mydriatic cameras, where fundus photographs are taken by technicians linked by telemedicine to a reference centre, where ophthalmologists grade the images. Currently in the Ile-de-France region, 16 screening centres are linked through a central server to an ophthalmologic reading centre and includes 11 centres located in the diabetes departments of 11 hospitals, one diabetic retinopathy screening centre located in northern Paris, three in healthcare centres and one in a prison. RESULTS: During the 28-month evaluation period, 15,307 DR screening examinations were performed. Retinal photographs of at least one eye could not be graded in 1332 patients (9.7%) and diabetic retinopathy was detected in 3350 patients (23.4%). After the screening examination, 3478 patients (25.2%) were referred to an ophthalmologist for either DR, cataract and/or non-gradable photographs. CONCLUSION: Fundus photography combined with telemedicine has the potential to improve the regular annual evaluation for diabetic retinopathy. The organization of the network around a central reading centre serves to guarantee quality control.

Macular pattern dystrophy in MIDD: long-term follow-up.

A case of maternally inherited diabetes and deafness (MIDD)-associated macular pattern dystrophy with a 15-year follow-up is reported. On initial examination at age 37, visual acuity was normal, but chorioretinal atrophy at the posterior pole was already present in both eyes. At age 52, visual acuity remained normal in the right eye and was only slightly decreased in the left eye despite notable extension of the areas of chorioretinal atrophy in that eye. No evidence of diabetic retinopathy was present at any time. This case shows that visual acuity can remain stable in the long term despite extensive lesions of macular pattern dystrophy.

Breast and ovarian cancer predisposition due to de novo BRCA1 and BRCA2 mutations.

BRCA1 and BRCA2 are the two major genes predisposing to breast and ovarian cancer. Whereas high de novo mutation rates have been demonstrated for several genes, only 11 cases of de novo BRCA1/2 mutations have been reported to date and the BRCA1/2 de novo mutation rate remains unknown. The present study was designed to fill this gap based on a series of 12 805 consecutive unrelated patients diagnosed with breast and/or ovarian cancer who met the inclusion criteria for BRCA1/2 gene analysis according to French guidelines. BRCA1/2 mutations were detected in 1527 (12%) patients, and three BRCA1 mutations and one BRCA2 mutation were de novo. The BRCA1/2 de novo mutation rate was estimated to be 0.3% (0.1%; 0.7%). Although rare, it may be useful to take the possibility of de novo BRCA1/2 mutation into account in genetic counseling of relatives and to improve the understanding of complex family histories of breast and ovarian cancers.

Advanced glycation end products can induce glial reaction and neuronal degeneration in retinal explants.

BACKGROUND/AIMS: Neuronal degeneration has been reported to occur in diabetic retinopathy before the onset of detectable microvascular abnormalities. To investigate whether advanced glycation end products (AGE) could be directly responsible for retinal neurodegeneration, retinal explants were incubated with glycated bovine serum albumin (BSA). METHODS: Retinal explants obtained from non-diabetic adult rats were incubated 4 days with or without 200 mug/ml glycated BSA. Neural apoptosis was quantified by terminal dUTP nick end labelling (TUNEL) binding and immunostaining with anti-cleaved caspase-3 antibody. Expression of glial fibrillary acidic protein (GFAP) was localised by immunofluorescence. RESULTS: TUNEL and cleaved caspase-3 positive cells increased significantly by 2.2-fold and 2.5-fold in retinal explants incubated in glycated BSA (p<0.05), respectively. The ganglion cell layer was the most sensitive retinal layer to the glycated BSA. Neuronal degeneration was confirmed by the increased GFAP labelling in Müller glial cells from retinal explants treated with glycated BSA. CONCLUSION: These results suggest that AGE could induce retinal neurodegeneration in the absence of blood perfusion. Cells in the ganglion cell layer appeared to be the most sensitive as in diabetic retinopathy and its animal models. AGE toxicity could therefore contribute to the early pathological mechanisms of diabetic retinopathy.

[Optic neuropathy associated with primary antiphospholipid syndrome]. / Neuropathie optique associée à un syndrome primaire des anti-phospholipides.

We describe a 45-year-old male patient with an atypical unilateral optic neuropathy who was diagnosed with primary antiphospholipid syndrome. The initially poor vision lasting several months completely recovered and long-term oral anticoagulation therapy prevented potential further systemic thrombotic complications.

Design and synthesis of hydrazinopeptides and their evaluation as human leukocyte elastase inhibitors.

The name hydrazinopeptide designates peptidic structures in which one of the native CONH links is replaced by a CONHNH (hydrazido) fragment. In this paper, we report the synthesis of such hydrazinohexapeptides (3-5) analogous to Z-Ala-Ala-Pro-Val-Ala-Ala-NHiPr (6), a substrate of human leukocyte elastase (HLE; EC 3.4.21.37), cleaved by this serine protease between the Val4 and Ala5 residues. In hydrazinopeptides 3-5, the Ala5, Val4, or Pro3 residue, respectively, of the model peptide, has been replaced by the corresponding alpha-L-hydrazino acid. In 3, the bond likely to be cleaved by HLE is the one involving the CONHNH link, while in 4 and 5, this link is normally shifted away by one or two amino acid units from the catalytic serine. On incubation with HLE, hydrazinopeptide 3 proved to be a substrate and was cleaved between Val4 and NHAla5, like peptide 6. In contrast, 4 and 5 proved to bind to HLE without being cleaved, featuring properties consistent with reversible competitive inhibition. General guidelines for the synthesis of hydrazinopeptides are also reported in this paper. These guidelines take into account the chemical specificity of hydrazino acids, while being fully compatible with the conventional peptide coupling techniques. The utilization of orthogonally bisprotected hydrazino acids 1 where the Nbeta and Nalpha atoms bear a Boc and a Bzl group, respectively, is recommended for the easy construction of such hydrazinopeptides.

Preservation of alveolar type II pneumocyte lamellar bodies for electron microscopic studies.

Simultaneous fixation with glutaraldehyde and osmium tetroxide, followed by an uranyl acetate (UA) treatment before dehydration and embedding (Hirsch and Fedorko 1968) ensures a very good preservation of lamellar bodies (LB's) as well as of the cellular membranes in type II pneumocyte. The uranyl acetate treatment appeared to be the most efficient step of the procedure. The morphological aspect of lamellar bodies after such a preparation was similar to that observed after freeze-etching of lipid retaining methods. Moreover, the Hirsch-Fedorko procedure is very simple and can easily be used for routine ultrastructural and radioautographic studies. On the other hand, it appeared that the uranyl acetate phospholipid "complex" is very sensitive to the pH of chemical solutions used after sectioning. The "complex" is variously dissolved by alkaline solutions, photographic developers or stains. The best preservation of ultrastructure was obtained with neutral or acidic developers and acidic stains.

Anastomosis of the ovarian vein to the hepatic portal vein in sheep induces ovarian hyperstimulation associated with increased LH pulsatility, but only in the absence of the contralateral ovary.

In this study, two experiments were performed, the first of which examined the ovarian response in ewes that were subject to unilateral ovariectomy (ULO) at different intervals (0-14 days) after surgical anastomosis (AN) of the ovarian vein to the mesenteric vein (n=7 ewes), or sham operation (SO; n=4 ewes). Hypertrophy and development of multiple follicular and luteal structures on AN ovaries were observed after ULO, while SO ovaries remained of normal size and appearance after ULO. The second experiment involving 11 ewes (five AN; six SO) aimed to clarify the mechanism by which AN following ULO-induced ovarian hypertrophy and increased follicle development. The results confirmed that there were more large (>5 mm) follicles on AN compared with SO ovaries; however, their rate of atresia was similar. Oestradiol and progesterone concentrations in follicular fluid of class 1 follicles (5-9 mm) were higher in AN ovaries than those in control follicles of the same size collected in the late follicular phase of an induced oestrous cycle. In AN ewes, intrafollicular progesterone concentrations increased while follicular aromatase activity and intrafollicular oestradiol, inhibin A, follistatin and activin A concentrations all decreased as follicle size increased. Oestradiol and progesterone concentrations were substantially higher in ovarian venous blood than in hepatic venous blood, both in AN and SO ewes, whereas inhibin A levels were not significantly modified by passage through the liver in either group. Mean plasma LH concentration, and LH pulse frequency and amplitude increased markedly after AN but were not affected by SO. Plasma FSH showed only a small transient increase after AN, presumably due to the maintenance of inhibin feedback. Injection of prostaglandin F(2)(alpha) 4 days later did not further modify LH or FSH secretion in either group. Full ovariectomy (FO) 9-14 days after AN or SO increased LH secretion markedly in SO ewes but to a lesser degree in AN ewes; FO induced a large and rapid increase in FSH levels in both groups. In conclusion, AN of the ovary to the liver via the mesenteric vein provides a useful model for studying the feedback between the ovary and the hypothalamo-pituitary system and the mechanisms controlling follicle development. The present results indicate that the pattern of LH secretion is an important factor controlling the terminal phase of follicle development in the ewe.

Can monoatomic xenon become chiral?

A chiral host, cryptophane-A (1), makes even a monoatomic noble gas chiral. The interaction of xenon and 1 was monitored by (129) Xe NMR and in the presence of a chiral chemical shift reagent.

Functional maturation of the oligodendrocytes and myelin basic protein expression in the olfactory bulb of the mouse.

The timing of myelin basic protein (MBP) expression and myelin component synthesis by the oligodendrocytes of the olfactory bulb was investigated in the mouse. Immunostaining with an anti-MBP immunoserum and a radioimmunoassay determination of MBP allowed to study the timing of MBP deposition during the development in this structure. Immunostaining of dissociated cells with anti-MBP and anti-galactosylceramide (anti-GC) was used to determine the state of development when these markers become expressed by olfactory bulb oligodendrocytes. Investigations using dissociated cells showed that GC-positive oligodendrocytes are already detected 3 days after birth in the olfactory bulb of the mouse and MBP is expressed 4 days later. Myelinated fibers were not visible on cryostat sections of olfactory bulb before 8 days postnatal. This work has been initiated by observations on the timing of myelination of olfactory bulb oligodendrocytes in transplantation experiments.

Effects of soman-induced seizures on different extracellular amino acid levels and on glutamate uptake in rat hippocampus.

Extracellular amino acid levels in CA3 and CA1 fields of rat hippocampus, an area highly sensitive to seizures, were determined by intracranial microdialysis during seizures induced by systemic administration of soman (o-1,2,2-trimethylpropyl methylphosphonofluoridate), a potent inhibitor of acetylcholinesterase. The glutamate uptake level was determined on another series of animals in hippocampus homogenates. An early and transient increase in the extracellular glutamate level occurred in CA3 within 30 min of seizures, with correlated brief elevations of taurine, glycine and glutamine levels. The glutamate level increased early in CA1, declined and then became more sustained (after 50 min of seizures). Apparent elevations of taurine, glycine and glutamine levels in CA1 accompanied changes in glutamate concentrations. Changes of glutamate level correlated with an increase in the glutamate uptake which rapidly declined after 40 min of seizures. The role of the transient release of glutamate in CA3 and of the sustained release in CA1 in prolonged soman-induced seizures is considered. The correlation between glutamate and other amino acid release is studied.

Transient impairment of the gabaergic function during initiation of soman-induced seizures.

The changes in extracellular gamma-aminobutyric acid (GABA) levels, the modifications in binding capacities of GABA-receptor subtypes A and B and of the Cl- ionophore sites localized in the ionic-channel associated to the GABAA receptors were studied in hippocampus of rats subjected to a convulsive dose of the acetylcholinesterase inhibitor soman. Whereas extracellular GABA levels, just as binding on GABAA and GABAB receptors, were not modified under soman, a significant transient decrease in the binding capacities of the Cl- ionophore site of the GABAA receptor complex occurred within the first 10 min of seizures in CA1, CA3 areas, and in the dentate gyrus with return to basal values after 30 min. Accordingly, a transient decrease of the brain muscimol-gated Cl- influx was observed after 10 min of seizures. An increased ability of diazepam to potentiate the GABAA gated Cl- influx occurred at the same time. Altogether, these data demonstrated that an impairment of the GABAA receptor function occurs at the beginning of seizures. This suggests that a temporary decrease of GABAAergic function may contribute to the onset of seizures.

Influence of medial septal cholinoceptive cells on c-Fos-like proteins induced by soman.

The effects of intraseptal application of atropine on c-fos proto-oncogene expression related to soman treatment were studied by immunohistochemistry for c-Fos-like proteins. In control rats, 2 h after the onset of convulsion, c-Fos-like immunoreactivity was intense in the piriform and entorhinal cortices, but also in the cingulate, frontoparietal and retrosplenial cortices. In addition, the staining was moderate in the hypothalamus, amygdala and fascia dentata. The intraseptal application of atropine, which prevented soman-induced convulsions, reduced or even blocked c-Fos-like protein production related to soman treatment. This inhibition of Fos induction was significant in most of the limbic structures but also in non-limbic areas. The data in this study strongly suggest that the cholinergic cells of the medial septal area play a key role in soman-induced seizures, and confirm that c-Fos-like protein induction is closely related to neuronal hyperactivity.

Tamm-Horsfall protein, a kidney marker is expressed on brain sulfogalactosylceramide-positive astroglial structures.

The Tamm-Horsfall (TH) glycoprotein and the acidic glycosphingolipid sulfogalactosylceramide (SGC) have a strictly superimposable localization on kidney tissue sections. The fact that SGC is a prevalent glycolipid in mammalian brain, prompted us to look for the presence of TH in the rat central nervous system (CNS). An antiserum raised against human TH was found to react with rat CNS homogenate in the complement fixation assay. This anti-TH antiserum recognized a rat CNS protein having an identical electrophoretical mobility on SDS polyacrylamide gel electrophoresis (PAGE). Indirect immunofluorescence on rat brain tissue sections allowed us to localize this brain TH cross-reacting material to ependymal cells and astrocytic processes such as the Bergmann fibers or astrocytic feet in contact with either the blood vessels or the meninges. All these astroglial structures are also SGC-positive. Since TH and SGC in the kidney are localized on a membrane that possesses an electrogenic Cl-pump, we propose that the astroglial structures which contain these two molecules are also the site of a Cl-transport system.

Early and transient increase of rat hippocampal blood-brain barrier permeability to amino acids during kainic acid-induced seizures.

The effects of kainic acid (KA) induced seizures on the permeability of hippocampal blood-brain barrier (BBB) to amino acids were investigated using a new method based on the combination of brain microdialysis of alpha-[3H]aminoisobutyric acid (AIB) and blood sampling. The transfer of AIB through the BBB was thus, for the first time, monitored in vivo in awake animals. KA administration i.v. produces a rapid and transient increase in hippocampal transfer of AIB after the beginning of seizures which is closely correlated to epileptic activity. The possible consequences of this increased transport of AIB from blood to brain are discussed in relation to previously reported transient augmentations of extracellular cerebral glutamate concentrations during KA-induced epilepsy.