Primary Hyperoxaluria Type 1 with Homozygosity for a Double-mutated AGXT Allele in a 2-year-old Child.

Primary hyperoxaluria (PH) Type 1 is a rare, genetic disorder caused by deficiency of the liver enzyme alanine-glyoxylate aminotransferase, which is encoded by AGXT gene. We report a 2-year-old South Indian Tamil child with nephrocalcinosis due to PH Type 1, in whom a homozygous genotype for two missense mutations in the AGXT gene was found: first, a C to G transversion (c. 32C>G) in exon 1 resulting in the amino acid substitution p.Pro11Arg; second, a T to A transversion (c. 167T>A) in exon 2 resulting in p.Ile56Asn. A therapy based on potassium citrate and pyridoxine was started. This is the first report of molecular testing-proven childhood onset-PH Type 1 from South India and is notable for the co-occurrence of two missense mutations in one AGXT allele, which might lead to different and more severe phenotype than each mutation alone. To the best of our knowledge, AGXT allele carrying two already known mutations has not been previously reported.

PVA/Dextran hydrogel patches as delivery system of antioxidant astaxanthin: a cardiovascular approach.

After myocardial infarction, the heart's mechanical properties and its intrinsic capability to recover are compromised. To improve this recovery, several groups have developed cardiac patches based on different biomaterials strategies. Here, we developed polyvinylalcohol/dextran (PVA/Dex) elastic hydrogel patches, obtained through the freeze thawing (FT) process, with the aim to deliver locally a potent natural antioxidant molecule, astaxanthin, and to assist the heart's response against the generated myofibril stress. Extensive rheological and dynamo-mechanical characterization of the effect of the PVA molecular weight, number of freeze-thawing cycles and Dex addition on the mechanical properties of the resulting hydrogels, were carried out. Hydrogel systems based on PVA 145 kDa and PVA 47 kDa blended with Dex 40 kDa, were chosen as the most promising candidates for this application. In order to improve astaxanthin solubility, an inclusion system using hydroxypropyl-ß-cyclodextrin was prepared. This system was posteriorly loaded within the PVA/Dex hydrogels. PVA145/Dex 1FT and PVA47/Dex 3FT showed the best rheological and mechanical properties when compared to the other studied systems; environmental scanning electron microscope and confocal imaging evidenced a porous structure of the hydrogels allowing astaxanthin release. In vitro cellular behavior was analyzed after 24 h of contact with astaxanthin-loaded hydrogels. In vivo subcutaneous biocompatibility was performed in rats using PVA145/Dex 1FT, as the best compromise between mechanical support and astaxanthin delivery. Finally, ex vivo and in vivo experiments showed good mechanical and compatibility properties of this hydrogel. The obtained results showed that the studied materials have a potential to be used as myocardial patches to assist infarcted heart mechanical function and to reduce oxidative stress by the in situ release of astaxanthin.

Copy number variants analysis in a cohort of isolated and syndromic developmental delay/intellectual disability reveals novel genomic disorders, position effects and candidate disease genes.

BACKGROUND: Array-comparative genomic hybridization (array-CGH) is a widely used technique to detect copy number variants (CNVs) associated with developmental delay/intellectual disability (DD/ID). AIMS: Identification of genomic disorders in DD/ID. MATERIALS AND METHODS: We performed a comprehensive array-CGH investigation of 1,015 consecutive cases with DD/ID and combined literature mining, genetic evidence, evolutionary constraint scores, and functional information in order to assess the pathogenicity of the CNVs. RESULTS: We identified non-benign CNVs in 29% of patients. Amongst the pathogenic variants (11%), detected with a yield consistent with the literature, we found rare genomic disorders and CNVs spanning known disease genes. We further identified and discussed 51 cases with likely pathogenic CNVs spanning novel candidate genes, including genes encoding synaptic components and/or proteins involved in corticogenesis. Additionally, we identified two deletions spanning potential Topological Associated Domain (TAD) boundaries probably affecting the regulatory landscape. DISCUSSION AND CONCLUSION: We show how phenotypic and genetic analyses of array-CGH data allow unraveling complex cases, identifying rare disease genes, and revealing unexpected position effects.

A fine structural modification of glycosaminoglycans is correlated with the progression of muscle regeneration after ischaemia: towards a matrix-based therapy?

Critical limb ischaemia often leads to amputation of the limb and potential mortality. Moreover, there are still significant problems with current therapeutic treatments, according to poor revascularisation of degenerated tissue probably due to modifications within the microenvironment. This study is focused on the changes of structure and bioactivity of glycosaminoglycans (GAGs), especially heparan sulphate (HS) and chondroitin sulphate (CS) in rat Extensor Digitorum Longus (EDL) muscle after ischaemia. Male Wistar rats were subjected to ischaemic-injury by ligation of the neurovascular trunk accompanying EDL-tendon. After 4, 8, 15, 21, 60 and 90 d, the rats were sacrificed and the muscles were collected and submitted to histological, biochemical and gene expression assays. We demonstrated that ischaemia induced modification of expression of enzymes involved in GAG biosynthesis which correlated with significant changes in HS and CS structural features such as size and sulphation pattern. These major structural changes are associated to modifications of GAG abilities to bind growth factors and to modulate cell activity. Moreover, a CS hallmark of injury is maintained as well after the regeneration process. Finally, we showed the relevance of the role of this glycanic matrix remodelling, since a GAG mimetic treatment accelerated muscle repair after ischaemia.

Shape-memory starch for resorbable biomedical devices.

Shape-memory resorbable materials were obtained by extrusion-cooking of potato starch with 20% glycerol under usual conditions. They presented an efficient shape-memory with a high recovery ratio (Rr>90%). Their recovery could be triggered at 37°C in water. After water immersion at 37°C, the modulus decreased from 1GPa to 2.4MPa and remained almost constant over 21 days. Gamma-ray sterilization did not have a dramatic impact on their mechanical properties, despite a large decrease of molecular mass analyzed by asymmetrical flow field-flow fractionation coupled with multi-angle laser light scattering (AFFFF-MALLS). Samples implanted in a rat model exhibited normal tissue integration with a low inflammatory response. Thus, as previously investigated in the case of shape-memory synthetic polymers, natural starch, without chemical grafting, can now be considered for manufacturing innovative biodegradable devices for less-invasive surgery.

RANTES/CCL5-induced pro-angiogenic effects depend on CCR1, CCR5 and glycosaminoglycans.

Atherosclerosis involves angiogenesis and inflammation with the ability of endothelial cells and monocytes to respond to chemokines. We addressed here by in vitro and in vivo approaches, the role of the chemokine Regulated on Activation, Normal T Cell Expressed and Secreted (RANTES)/CCL5 on angiogenesis through its receptors CCR1, CCR5, syndecan-1 (SDC-1), syndecan-4 (SDC-4) and CD-44. Our data demonstrate that RANTES/CCL5 is pro-angiogenic in a rat subcutaneous model. This RANTES/CCL5-activity may be related to the in vitro promotion of endothelial cell migration, spreading and neo-vessel formation. RANTES/CCL5-mediated angiogenesis depends at least partly on Vascular Endothelial Growth Factor (VEGF) secretion by endothelial cells, since this effect is decreased when endothelial cells are incubated with anti-VEGF receptor antibodies. RANTES/CCL5-induced chemotaxis is mediated by matrix metalloproteinase-9. We demonstrate that specific receptors of RANTES/CCL5 such as G protein-coupled receptors CCR1 and CCR5, and heparan sulfate proteoglycans, SDC-1, SDC-4 or CD-44, play a major role in RANTES/CCL5-induced angiogenic effects. By the use of two RANTES/CCL5 mutants, [E66A]-RANTES/CCL5 with impaired ability to oligomerize, and [44AANA47]-RANTES/CCL5 mutated in the main RANTES/CCL5-glycosaminoglycan (GAG) binding site, we demonstrate that chemokine oligomerization and binding to GAGs are essential in RANTES/CCL5-induced angiogenic effects. According to these results, new therapeutic strategies based on RANTES/CCL5 can be proposed for neo-angiogenesis after vascular injury. Mutants of RANTES/CCL5 may also represent an innovative approach to prevent the angiogenesis associated with the formation of atherosclerotic plaque.

Effects of acute prednisolone intake during intense submaximal exercise.

To study the effects of a therapeutical dose of corticosteroid alone or associated with beta-2 agonist on performance and substrate response during intense submaximal exercise, seven healthy moderately trained male volunteers participated in the double-blind randomized cross-over study. An intense endurance exercise test to exhaustion was performed after ingestion of placebo (Pla), 20 mg prednisolone (Pred), and 20 mg prednisolone plus 4 mg salbutamol (Pred-Sal). Blood samples were collected at rest, after 5, 10 min of exercise, at exhaustion, and after 5 (r5), 10 (r10), and 20 (r20) min of passive recovery for ACTH, growth hormone, insulin, blood glucose, and lactate measurements. There were no significant differences in exercise time to exhaustion between the three treatments (Pla: 21.5 +/- 2.9; Pred: 22.0 +/- 2.5; Pred-Sal: 24.2 +/- 2.8 min). ACTH was significantly lowered after Pred and Pred-Sal vs. Pla from the start of exercise to the end of the experiment (p < 0.05). Pred and Pred-Sal increased resting and recovery (r10 and r20) significantly but not exercise blood glucose values. There were no significant differences in growth hormone concentrations between the three treatments whereas insulin was significantly higher at rest, during exercise, and at r20 after Pred-Sal administration vs. Pred and Pla (p < 0.05). Pred and Pred-Sal showed no significant effect on blood lactate compared with Pla treatment. These preliminary results do not support the hypothesis that acute oral therapeutic corticosteroid intake alone or associated with beta-2 mimetic improves performance during intense submaximal exercise, but further studies are necessary with tests of longer duration.

New antibody purification procedure using a thermally responsive poly(N-isopropylacrylamide)-dextran derivative conjugate.

Through their specificity and affinity, antibodies are useful tools in research and medicine. In this study, we investigated a new type of chromatographic method using a thermosensitive polymer for the purification of antibodies against a dextran derivative (DD), as a model. The thermally reversible soluble-insoluble poly(N-isopropylacrylamide)-dextran derivative conjugate, named poly(NIPAAm)-DD, has been synthesized by conjugating amino-terminated poly(N-isopropylacrylamide) to a DD via ethyl-3-(3-dimethylaminopropyl)-carbodiimide. On one hand, this report describes the two steps of poly(NIPAAm)-DD conjugation and characterization. On the other hand, the poly(NIPAAm)-DD conjugate was used as a tool to purify polyclonal antibodies in serum samples from rabbits subcutaneously immunized with the derivatized dextran. Antibodies were purified and quantified by immunoenzymatic assays. Our results indicate that antibodies recognized both DD and poly(NIPAAm)-DD. In contrast, they did not bind to native poly(NIPAAm) or poly(NIPAAm) conjugated with another anionic dextran. We conclude that the conjugation of a polysaccharide to poly(NIPAAm) leads to an original and efficient chromatographic method to purify antibodies. Moreover, this novel method of purification is rapid, sensitive, inexpensive and could be used to purify various types of antibodies.

[Recurrent fever episodes in an African child: diagnostic difficulties of trypanosomiasis in France]. / Accès fébriles à répétition chez un enfant africain: difficultés diagnostiques d'une trypanosomiase en France.

A young Angolian boy who had emigrated to France at the age of 2, presented with a long history of fever. Gambian Trypanosomiasis was diagnosed with peculiar aspects: 1) evolution of adult sickness with a long hemolymphatic period (first stage) and a subacute worsening period with neurologic deficit and somnolence (second stage); 2) a possible post-transfusional contamination: the young boy, born in South Angola, a nor-highly endemic area, was transfused at the age of 10 months with the blood of a donor who was subsequently treated for Trypanosomiasis; 3) a suppurating adenopathy; 4) a predominance of IgG within the hypergammaglobulinemia while IgM are the predominant immunoglobulins in this affection; 5) a hepatic toxicity of Difluoromethylornithine.

Postnatal development of pretectal and NRTP neuron responses to optokinetic stimulation in the rat.

The postnatal development of single unit responses in the pretectum (Pt) and the nucleus reticularis tegmenti pontis (NRTP) to large horizontal moving visual patterns at constant velocity (range 0.5-5 deg./s) has been studied in pigmented rats (DA/HAN). The earliest detectable response was recorded on postnatal day 16 in the Pt and day 19 in the NRTP. The number of responding units increased with age: 36% in group I (16-26 days) and 60% in group II (27-36 days) in Pt; 43% and 61% in group I (19-26 days) and II (27-36 days), respectively, in NRTP. Response magnitude developed gradually: Mean delta F (impulses/s) = 4.9 and 7.6 in group I and II, respectively, in Pt and 6.1 and 7.9 in group I and II, respectively, in NRTP. Different types of response patterns were identified relative to their ocular origin and directionality of the stimulation. In addition to the adult-like patterns, other units were either excited or inhibited by stimulation of the ipsilateral eye. These findings indicate that movement-evoked responses of Pt and NRTP neurons appear earlier than vestibular nucleus (VN) responses to such visual stimuli, and that the day of response appearance progresses along the visual-vestibular pathways from the primary central relay. The maturation is characterized by a relative decrease in time in the role of ipsilateral afferents and a relative increase in time in the role of contralateral afferents. As these contralateral afferents to the Pt are well known to be involved in generating optokinetic nystagmus, the postnatal increase in the sensitivity of their responses may parallel the postnatal development of optokinetic behavior in the rat.

Skin eosinophilia from influenza viruses. An experimental histological study.

The authors would first like to stress the increasing frequency of bronchial asthma during or after influenza. To find an explanation for this occurrence they observed tissue reactions following an injection of viral material. In their experiments, they injected into the skin of guinea pigs, strains of the Hong Kong, Texas and USSR influenza viruses using current vaccines, sacrificing groups of animals 2, 6, 24, 48 hours and 7 days after the injection. The histological study revealed the following picture of reaction to influenza viruses. Two hours after the injection: marked and diffuse infiltration of eosinophils in the connective tissue of the skin. After 6 hours: the infiltration shows a predominance of neutrophils. After 24 hours: the neutrophil infiltration is predominant and diffuse. There is evidence of considerable degranulation of eosinophils. The cutaneous histiocytes undergo fibrocytic and marcophagic proliferation. After 28 hours, the same picture. After 7 days there is sever degeneration with a peripheral fibroblastic reaction. The most important finding of this experiment is the early marked infiltration of eosinophils which follows the injection of the influenza viruses. The eosinophil infiltration appears to be related to the release of histamine caused by influenza viruses. The histological examination did not reveal the presence of immune allergic-type cells at any time. Therefore, the onset of asthmatic attacks would appear to be more related to the histamine-releasing action of the influenza viruses rather than to their sensitizing activity. Naturally, the latter may occur in human pathologies.