A novel erythroid anion exchange variant (Gly796Arg) of hereditary stomatocytosis associated with dyserythropoiesis

Background

Stomatocytoses are a group of inherited autosomal dominant hemolytic anemias and include overhydrated hereditary stomatocytosis, dehydrated hereditary stomatocytosis, hereditary cryohydrocytosis and familial pseudohyperkalemia.

Design and Methods

We report a novel variant of hereditary stomatocytosis due to a de novo band 3 mutation (p. G796R-band3 CEINGE) associated with a dyserythropoietic phenotype. Band 3 genomic analysis, measurement at of hematologic parameters and red cell indices and morphological analysis of bone marrow were carried out. We then evaluated the red cell membrane permeability and ion transport systems by functional studies of the patient’s erythrocytes and Xenopus oocytes transfected with mutated band 3. We analyzed the red cell membrane tyrosine phosphorylation profile and the membrane association of the tyrosine kinases Syk and Lyn from the Src-family-kinase group, since the activity of the membrane cation transport pathways is related to cyclic phosphorylation-dephosphorylation events.

Results

The patient showed mild hemolytic anemia with circulating stomatocytes together with signs of dyserythropoiesis. Her red cells displayed increased Na⁺ content with decreased K⁺content and abnormal membrane cation transport activities. Functional characterization of band 3 CEINGE in Xenopus oocytes showed that the mutated band 3 is converted from being an anion exchanger (Cl⁻, HCO₃⁻) to being a cation pathway for Na⁺ and K⁺. Increased tyrosine phosphorylation of some red cell membrane proteins was observed in diseased erythrocytes. Syk and Lyn membrane association was increased in the patient’s red cells compared to in normal controls, indicating perturbation of phospho-signaling pathways involved in cell volume regulation events.

Conclusions

Band 3 CEINGE alters function from that of anion exchange to cation transport, affects the membrane tyrosine phosphorylation profile, in particular of band 3 and stomatin, and its presence during red cell development likely contributes to dyserythropiesis.     

GDNF Selectively Induces Microglial Activation and Neuronal Survival in CA1/CA3 Hippocampal Regions Exposed to NMDA Insult through Ret/ERK Signalling

The glial cell line-derived neurotrophic factor (GDNF) is a potent survival factor for several neuronal populations in different brain regions, including the hippocampus. However, no information is available on the: (1) hippocampal subregions involved in the GDNF-neuroprotective actions upon excitotoxicity, (2) identity of GDNF-responsive hippocampal cells, (3) transduction pathways involved in the GDNF-mediated neuroprotection in the hippocampus. We addressed these questions in organotypic hippocampal slices exposed to GDNF in presence of N-methyl-D-aspartate (NMDA) by immunoblotting, immunohistochemistry, and confocal analysis. In hippocampal slices GDNF acts through the activation of the tyrosine kinase receptor, Ret, without involving the NCAM-mediated pathway. Both Ret and ERK phosphorylation mainly occurred in the CA3 region where the two activated proteins co-localized. GDNF protected in a greater extent CA3 rather than CA1 following NMDA exposure. This neuroprotective effect targeted preferentially neurons, as assessed by NeuN staining. GDNF neuroprotection was associated with a significant increase of Ret phosphorylation in both CA3 and CA1. Interestingly, confocal images revealed that upon NMDA exposure, Ret activation occurred in microglial cells in the CA3 and CA1 following GDNF exposure. Collectively, this study shows that CA3 and CA1 hippocampal regions are highly responsive to GDNF-induced Ret activation and neuroprotection, and suggest that, upon excitotoxicity, such neuroprotection involves a GDNF modulation of microglial cell activity.     

The role of fractionated radiotherapy and radiosurgery in the management of patients with craniopharyngioma

The optimal management of craniopharyngiomas remains controversial. The first-line treatment usually consists of surgical resection. Complete tumor removal provides a high rate of long-term control; however, aggressive surgery is associated with significant incidence of complications. Radiotherapy (RT) is currently used in patients after limited surgery and achieves excellent long-term tumor control. Stereotactic radiotherapy, both in the form of radiosurgery (RS) or fractionated stereotactic radiotherapy (FSRT), has been developed as a more accurate technique of irradiation with more precise tumor localization and consequently a reduction in the volume of normal brain irradiated to high radiation doses. We provide a review of published data on outcome of conventional fractionated RT and modern radiation techniques. FSRT is a suitable treatment technique for all sizes of craniopharyngiomas, and efficacy is comparable to conventional RT. Single-fraction stereotactic radiosurgery is usually delivered to small tumors away from critical structures. Longer follow-up is necessary to confirm the excellent tumor control and the potential reduction of long-term radiation toxicity.     

Is prophyilaxis necessary after urodynamic tests? Our experience

Urodynamic studies should be performed only on patients with sterile urine. The use of prophylaxis after urodynamic investigation is debated (positive urinoculture in 9 to 15% of cases). The Units of Urodynamics at the Urological Clinic of the University of Genoa and of the Galliera Hospital of Genoa assessed the prevalence of bacteriuria on a sample of 336 patients (314 females and 22 males), average age 62.3, between January and December 2006. All patients with sterile urine before examination underwent a complete urodynamic test. Concomitant diseases were: diabetes (7.7%), multiple sclerosis (3.5%), Parkinson's disease (1.2%), urinary retention treated by autocatheterism (1.2 %). Urinoculture was performed seven days after the urodynamic study. All patients were asymptomatic; 40/336 urinocultures were positive (E. coli 80%, Proteus M. 10%, other 10%). The prophylaxis does not eliminate but only reduces post-urodynamic infections; we believe that the cost-benefit ratio is unfavorable.     

Defining New Pancreatic Tumour Entities by Molecular Analysis

Recent advances in molecular biology, biochemistry and genetics have broadened our understanding of tumourigenesis and of the maintenance and spread of pancreatic cancer far beyond traditional microscopic histopathological analysis. While the main focus of pancreatic cancer research has been on pancreatic ductal adenocarcinoma, molecular research hasalso led toa better understanding of rare tumours of the pancreas, as well as to the definition of previously unknown tumour entities that can only be identified through the application of molecular tools. Furthermore, molecular analysis increasingly reveals the genetic and cell biological heterogeneity of established tumour entities, making sub-classification of tumours possible. Genetic and molecular approaches may, therefore, not only lead to a better understanding of the pathogenesis of pancreatic tumours, but also culminate in more precise diagnosis as well as individually tailored treatment strategies for affected patients.     

Neuroprotection afforded by some hindered phenols and α-tocopherol in guinea-pig detrusor strips subjected to anoxia-glucopenia and reperfusion-like conditions

2-t-butyl-4-methoxyphenol (BHA), 3,5-di-t-butyl-hydroxyanisole (DTBHA), 2,6-diisopropylphenol (propofol), alpha-tocopherol (alpha-TOC) and two newly synthesised analogues of BHA, namely 1-O-(4-hydroxy-3-t-butyl)phenyl-2,3,4,6-tetra-O-acetyl-beta-D-glucopyranose (beta-TAG) and 1-O-(4-hydroxy-3-t-butyl)phenyl-beta-D-glucopyranose (beta-GLU), were tested for their capability to protect the intrinsic nerves of guinea-pig urinary bladder from damage due to anoxia-glucopenia and re-exposure to glucose and O2. Guinea-pig detrusor strips were mounted for tension recording in small organ baths, superfused with warmed Krebs solution and the nerves stimulated electrically either under control or ischaemia-like (anoxia-glucopenia) and reperfusion-like conditions (normal medium re-superfusion). The Ca2+ antagonist activity of the compounds was assessed by their effect on the contraction of detrusor strips induced by 60 mM K+ Krebs solution in the presence of either 0.5 mM or 5 mM Ca2+. The antioxidant activity was illustrated by the ability of the compounds to scavenge peroxyl radicals generated by linoleic acid oxidation. All the compounds, except beta-GLU and alpha-TOC, inhibited in a concentration-dependent manner K+-induced contractions of detrusor muscles, the inhibition being inversely related to the Ca2+ concentration of the perfusion solution; moreover, they exhibited a marked antiperoxidant activity with pIC50 values decreasing in the order: DTBHA > alpha-TOC > BHA > beta-TAG > propofol > beta-GLU. alpha-TOC, BHA, DTBHA and beta-TAG improved significantly the response of the strips to electrical field stimulation either during the anoxia-glucopenia phase or thereafter when recovering during reperfusion, as compared to untreated tissues. The neuroprotection afforded by the phenol derivatives as well as by alpha-TOC was positively correlated to their antioxidant activity, but not to their Ca2+ antagonist activity.     

Congenital and Developmental Cataracts: Focus on Strabismus Outcomes at Long-Term Follow-Up

Purpose: To evaluate the incidence of strabismus in congenital and developmental cataract surgery in patients with a follow-up longer than five years. Methods: All patients with congenital and developmental cataracts observed from 1996 to 2013 with a follow-up longer than five years were retrospectively included. Results: We included 117 patients (58 females and 59 males, mean age 0.62±0.3 years, 160 eyes) with congenital cataracts and 73 patients (32 females and 41 males, mean age 6.63±0.7 years, 121 eyes) with developmental cataracts. Before cataract surgery, strabismus was present in 88 patients with congenital cataracts (75.2%) and in 30 patients with developmental cataracts (41.1%) (p=0.01). After a follow-up of 9.26±1.3 years (range, 5–14 years), a significantly greater incidence of strabismus was observed after surgery only in patients with unilateral congenital cataracts who underwent cataract removal and primary IOL implantation (p=0.02). Distance BCVA and near BCVA were better after surgery for developmental cataracts (p<0.05). Presence of binocular vision was more frequent after surgery for developmental cataracts (p=0.001). Conclusion: Incidence of strabismus and postsurgical onset of strabismus at long-term follow-up was greater in patients with congenital cataracts.