Genotype-Phenotype Variations of Renal Complications in Fabry Disease Q279X Mutation

Abstract In more than 800 GLA gene mutations causing Fabry Disease (FD), renal involvement vary according to the α-GAL A mutation. The aim is to describe the genotype/phenotype variations of renal complications in two siblings with confirmed FD with the mutation p.Q279X in exon 6. We present a retrospective study of two venezuelan male siblings, ages 34 (patient 1) and 33 (patient 2), evaluated by general lab tests, renal ultrasound, renal scintigram , and renal biopsy. Fabry disease diagnose was made by α-galactosidase A activity determined in dried blood spot. Genomic DNA was sequenced by Sanger method. Patient 1 developed CKD grade 5 and high blood pressure, treated by hemodialysis during 8 years. Patient 2 showed GFR >60 ml/min, and proteinuria less than 600 mg/24H. Renal biopsy showed segmental sclerotic lesions and hypertrophic podocytes with vacuolated cytoplasm. Both patients received ERT every two weeks since 2003. Patient 1 died because dialysis complications (hyperparathyroidism, cardiomyopathy). The genotype/phenotype variation of the c.835C>T mutation (p.Gln279Ter. Q279X) in exon 6 of the GLA gene can express an important renal variation with a wide range of clinical manifestations that cannot be predicted, therefore, an early nephrological evaluation and periodic follow-up of these patients are necessary.

A Novel non-sense Mutation in Keratin 10 Causes a Familial Case of Recessive Epidermolytic Ichthyosis.

Epidermolytic ichthyosis (EI) is a rare skin disorder characterized by generalized erythroderma and cutaneous blistering at birth, which is substituted by hyperkeratosis later in life. It is caused by autosomal dominant mutations in highly conserved regions of KRT1 and KRT10. To date, only 4 mutations with autosomal recessive inheritance of EI have been described in consanguineous families. All of them affect the 2B domain of KRT10. In the present study we describe four patients with EI (including one lethal case) born from unaffected parents in a consanguineous family of a native Venezuelan community. The objective of this study was to characterize the clinical, genetic and morphological aspects of the disease in this family, as well as understand its functional implications. Genomic DNA was sequenced for KRT10 and KRT1. Immunofluoresence for keratin expression was performed on cutaneous biopsies. After examination of cutaneous biopsies histology, our results showed hyperkeratosis and acantholysis with an expanded granular layer. Sequencing of KRT10 demonstrated a non-sense mutation (p.Tyr282Ter.) corresponding to the 1B domain of the protein in patients and a heterozygous pattern in other family members, resulting in complete absence of K10. The loss of K10 was compensated by upregulation of K14 and K17. In conclusion, this novel mutation in KRT10 is the first recessive genetic variation that is not located in the so called "hot spot" for recessive EI, suggesting that other areas of the gene are also susceptible for such mutations.

Acetylcholinesterase deficiency contributes to neuromuscular junction dysfunction in type 1 diabetic neuropathy.

Diabetic neuropathy is associated with functional and morphological changes of the neuromuscular junction (NMJ) associated with muscle weakness. This study examines the effect of type 1 diabetes on NMJ function. Swiss Webster mice were made diabetic with three interdaily ip injections of streptozotocin (STZ). Mice were severely hyperglycemic within 7 days after the STZ treatment began. Whereas performance of mice on a rotating rod remained normal, the twitch tension response of the isolated extensor digitorum longus to nerve stimulation was reduced significantly at 4 wk after the onset of STZ-induced hyperglycemia. This mechanical alteration was associated with increased amplitude and prolonged duration of miniature end-plate currents (mEPCs). Prolongation of mEPCs was not due to expression of the embryonic acetylcholine receptor but to reduced muscle expression of acetylcholine esterase (AChE). Greater sensitivity of mEPC decay time to the selective butyrylcholinesterase (BChE) inhibitor PEC suggests that muscle attempts to compensate for reduced AChE levels by increasing expression of BChE. These alterations of AChE are attributed to STZ-induced hyperglycemia since similar mEPC prolongation and reduced AChE expression were found for db/db mice. The reduction of muscle end-plate AChE activity early during the onset of STZ-induced hyperglycemia may contribute to endplate pathology and subsequent muscle weakness during diabetes.

Effects of hydroxamate metalloendoprotease inhibitors on botulinum neurotoxin A poisoned mouse neuromuscular junctions.

Currently the only therapy for botulinum neurotoxin A (BoNT/A) poisoning is antitoxin. Antidotes that are effective after BoNT/A has entered the motor nerve terminals would dramatically benefit BoNT/A therapy. Inhibition of proteolytic activity of BoNT/A light chain by metalloendoprotease inhibitors (MEIs) is under development. We tested the effects of MEIs on in vitro as well as in vivo BoNT/A poisoned mouse nerve-muscle preparations (NMPs). The K(i) for inhibition of BoNT/A metalloendoprotease was 0.40 and 0.36 muM, respectively, for 2,4-dichlorocinnamic acid hydroxamate (DCH) and its methyl derivative, ABS 130. Acute treatment of nerve-muscle preparations with 10 pM BoNT/A inhibited nerve-evoked muscle twitches, reduced mean quantal content, and induced failures of endplate currents (EPCs). Bath application of 10 muM DCH or 5 muM ABS 130 reduced failures, increased the quantal content of EPCs, and partially restored muscle twitches after a delay of 40-90 min. The restorative effects of DCH and ABS 130, as well as 3,4 diaminopyridine (DAP) on twitch tension were greater at 22 degrees C compared to 37 degrees C. Unlike DAP, neither DCH nor ABS 130 increased Ca(2+) levels in cholinergic Neuro 2a cells. Injection of MEIs into mouse hind limbs before or after BoNT/A injection neither prevented the toe spread reflex inhibition nor improved muscle functions. We suggest that hydroxamate MEIs partially restore neurotransmission of acutely BoNT/A poisoned nerve-muscle preparations in vitro in a temperature dependent manner without increasing the Ca(2+) levels within motor nerve endings.

Capsaicin protects mouse neuromuscular junctions from the neuroparalytic effects of botulinum neurotoxin a.

Botulinum neurotoxin A (BoNT/A), the most toxic, naturally occurring protein, cleaves synapse-associated protein of 25 kDa and inhibits acetylcholine release from motor nerve endings (MNEs). This leads to paralysis of skeletal muscles. Our study demonstrates that capsaicin protects mouse neuromuscular junctions from the neuroparalytic effects of BoNT/A. Bilateral injection of BoNT/A near the innervation of the Extensor digitorum longus (EDL) muscle of adult Swiss-Webster mice inhibited the toe spread reflex (TSR). However, when capsaicin was coinjected bilaterally, or injected 4 or 8 h before injecting BoNT/A, the TSR remained normal. In animals that were pretreated with capsazepine, capsaicin failed to protect against the neuroparalytic effects of BoNT/A. In vivo analyses demonstrated that capsaicin protected muscle functions and electromygraphic activity from the incapacitating effects of BoNT/A. The twitch response to nerve stimulation was greater for EDL preparations isolated from mice injected with capsaicin before BoNT/A. Capsaicin pretreatment also prevented the inhibitory effects of BoNT/A on end-plate currents. Furthermore, pretreatment of Neuro 2a cells with capsaicin significantly preserved labeling of synaptic vesicles by FM 1-43. This protective effect of capsaicin was observed only in the presence of extracellular Ca(2+) and was inhibited by capsazepine. Immunohistochemistry demonstrated that MNEs express transient receptor potential protein of the vanilloid subfamily, TRPV1, the capsaicin receptor. Capsaicin pretreatment, in vitro, reduced nerve stimulation or KCl-induced uptake of BoNT/A into motor nerve endings and cholinergic Neuro 2a cells. These data demonstrate that capsaicin interacts with TRPV1 receptors on MNEs to reduce BoNT/A uptake via a Ca(2+)-dependent mechanism.

Motor unit number estimate as a predictor of motor dysfunction in an animal model of type 1 diabetes.

Peripheral neuropathy is a common complication of diabetes that leads to severe morbidity. In this study, we investigated the sensitivity of motor unit number estimate (MUNE) to detect early motor axon dysfunction in streptozotocin (STZ)-treated mice. We compared the findings with in vitro changes in the morphology and electrophysiology of the neuromuscular junction. Adult Thy1-YFP and Swiss Webster mice were made diabetic following three interdaily intraperitoneal STZ injections. Splay testing and rotarod performance assessed motor activity for 6 wk. Electromyography was carried out in the same time course, and compound muscle action potential (CMAP) amplitude, latency, and MUNE were estimated. Two-electrode voltage clamp was used to calculate quantal content (QC) of evoked transmitter release. We found that an early reduction in MUNE was evident before a detectable decline of motor activity. CMAP amplitude was not altered. MUNE decrease accompanied a drop of end-plate current amplitude and QC. We also observed small axonal loss, sprouting of nerve endings, and fragmentation of acetylcholine receptor clusters at the motor end plate. Our results suggest an early remodeling of motor units through the course of diabetic neuropathy, which can be readily detected by the MUNE technique. The early detection of MUNE anomalies is significant because it suggests that molecular changes associated with pathology and leading to neurodegeneration might already be occurring at this stage. Therefore, trials of interventions to prevent motor axon dysfunction in diabetic neuropathy should be administered at early stages of the disorder.

Optimized transport setup for high repetition rate pulse-separated analysis in laser ablation-inductively coupled plasma mass spectrometry.

An optimized laser ablation setup, proposed for high repetition rate inductively coupled plasma mass spectrometry (ICPMS) analyses such as 2D imaging or depth profiling, is presented. For such applications, the particle washout time needs to be as short as possible to allow high laser pulse frequencies for reduced analysis time. Therefore, it is desirable to have an ablation setup that operates as a laminar flow reactor (LFR). A top-down strategy was applied that resulted in the present design. In the first step, a previously applied ablation setup was analyzed on the basis of computational fluid dynamics (CFD) results presented by D. Autrique et al. (Spectrochim. Acta, B 2008, 63, 257-270). By means of CFD simulations, the design was modified in such a way that it operated in the LFR regime. Experimental results demonstrate that the current design can indeed be regarded as an LFR. Furthermore, the operation under LFR conditions allowed some insight into the initial radial concentration distribution if the experimental ICPMS signal and analytical expressions are taken into account. Recommendations for a modified setup for more resilient spatial distributions are given. With the present setup, a washout time of 140 ms has been achieved for a 3% signal area criterion. Therefore, 7 Hz repetition rates can be applied with the present setup. Using elementary formulas of the analytical model, an upper bound for the washout times for similar setups can be predicted. The authors believe that the presented setup geometry comes close to the achievable limit for reliable short washout times.

Peptide-toxin tools for probing the expression and function of fetal and adult subtypes of the nicotinic acetylcholine receptor.

Although the neuromuscular nicotinic acetylcholine receptor (nAChR) is one of the most intensively studied ion channels in the nervous system, the differential roles of fetal and adult subtypes of the nAChR under normal and pathological conditions are still incompletely defined. Until recently, no pharmacological tools distinguished between fetal and adult subtypes. Waglerin toxins (from snake venom) and alphaA(S)-conotoxins (from cone-snail venom) have provided such tools. Because these peptides were characterized by different research groups using different methods, we have: 1) more extensively tested their subtype selectivity, and 2) begun to explore how these peptides may be used in concert to elucidate expression patterns and functions of fetal and adult nAChRs. In heterologous expression systems and native tissues, Waglerin-1 and an alphaA(S)-conotoxin analog, alphaA-OIVA[K15N], are high-affinity, highly selective inhibitors of the adult and fetal muscle nAChRs, respectively. We have used the peptides and their fluorescent derivatives to explore the expression and function of the fetal and adult nAChR subtypes. While fluorescent derivatives of these peptides indicated a gradual transition from fetal to adult muscle nAChRs in mice during the first 2 weeks postnatal, we unexpectedly observed a steeper transition in functional expression in the mouse diaphragm muscle using electrophysiology. As a toolkit of pharmacological agents with complementary specificity, alphaA-OIVA[K15N] and Waglerin-1 should have further utility in determining the roles of fetal and adult nAChR subtypes in development, in mature tissues, and under pathological conditions.

Depth analysis of polymer-coated steel samples using near-infrared femtosecond laser ablation inductively coupled plasma mass spectrometry.

The viability of near-infrared femtosecond laser ablation (fs-LA) inductively coupled plasma mass spectrometry (ICPMS) for the in-depth analysis of polymer coatings over galvanized steel substrates has been studied. A good depth resolution was obtained modifying the femtosecond Gaussian beam to a flat-top beam by using a liquid-crystal display. In order to avoid mixing of information coming from successive shots, a low repetition rate was accomplished and signals were monitored shot by shot. Different kinds of coatings were used to demonstrate the capability of femtosecond ablation for depth-profiling analysis. Ablation was conducted under He atmosphere, after sample cell Ar was admixed. The depth profiles obtained by LA-ICPMS are in good agreement with those obtained by GD-OES for the three analyzed samples. In cases where due to averaging over several millimeter sample roughness determines the depth resolution of GD-OES, it was found that LA-ICPMS achieves better depth resolution due to the better lateral resolution. The depth resolution obtained by LA-ICPMS was found to be 240 nm and 2.3 microm, for a hot-dip galvanized steel (HDGS) and a polymer-polymer-coated HDGS, respectively, compared to the 2.2 and 4.5 microm achieved with GD-OES for the same samples.

Diversity of long-chain toxins in Tityus zulianus and Tityus discrepans venoms (Scorpiones, Buthidae): molecular, immunological, and mass spectral analyses.

In Venezuela, stings by Tityus zulianus scorpions produce cardiorespiratory arrest, whereas envenoming by Tityus discrepans involves gastrointestinal/pancreatic complications, suggesting structural and/or functional differences. We sought to compare their toxin repertoires through immunological, molecular, and mass spectral analyses. First, in vivo tests showed that neutralization of T. zulianus venom toxicity by the anti-T. discrepans antivenom was not complete. To compare T. discrepans and T. zulianus long-chain (sodium channel-active) toxins, their most toxic Sephadex G-50 fractions, TdII and TzII, were subjected to acid-urea PAGE, which showed differences in composition. Amplification of toxin-encoding mRNAs using a leader peptide-based oligonucleotide rendered cDNAs representing twelve T. discrepans and two T. zulianus distinct toxin transcripts, including only one shared component, indicating divergence between T. zulianus and T. discrepans 5' region-encoded, toxin signal peptides. A 3'-UTR polymorphism was also noticed among the transcripts encoding shared components Tz1 and Td4. MALDI-TOF MS profiling of TdII and TzII produced species-specific spectra, with seven of the individual masses matching those predicted by cDNA sequencing. Phylogenetic analysis showed that the unique T. zulianus transcript-encoded sequence, Tz2, is structurally related to Tityus serrulatus and Centruroides toxins. Together with previous reports, this work indicates that T. zulianus and T. discrepans toxin repertoires differ structurally and functionally.

Isolation, molecular cloning and functional characterization of a novel beta-toxin from the Venezuelan scorpion, Tityus zulianus.

Sting in children by Tityus zulianus scorpions (western Venezuela) often produces cardiorespiratory arrest and death by pulmonary oedema. To assess its toxicity, lethality in mice of T. zulianus soluble venom was determined. Toxin composition was studied by fractionating the crude venom through reversed-phase HPLC. The most abundant peptide, Tz1, was purified further and its N-terminal sequence, amino acid composition and molecular mass (by electron-spray ionization mass spectrometry) determined. In the presence of Tz1, activation of recombinant rat skeletal muscle sodium channels (Na(V)1.4) was shifted about 35 mV in the hyperpolarizing direction in a prepulse-dependent manner. This typical beta-toxin effect had an apparent EC50 of 3.5 microM A cDNA sequence encoding Tz1 was isolated from T. zulianus venom gland RNA using a combination of 5'- and 3'-RACE PCR. Analysis of the encoded sequence indicated that Tz1 is the processed product of a precursor containing: (i) a 20-residue long leader peptide; (ii) the amino acid sequence of the mature toxin (64 residues); and (iii) an extra Gly-Lys tail at the C-terminus, probably removed post-translationally. A comparison of Tz1 with Tityus serrulatus beta-toxin Ts1 revealed that some of the non-conservative replacements in Tz1 lie in regions potentially involved in receptor recognition.

Síndrome adrenogenital por hiperplasia adrenal congénita (HAC) en la hembra. Presentación de 15 casos / Adrenogenital syndrome due to congenital adrenal hyperplasia (CAH) in girls. Report of 15 cases

Se presentaron 15 pacientes cromatin-positivos estudiados en las consultas de anomalías de la diferenciación sexual del IEEM, por ambigüedad de los genitales externos, virilización progresiva, manifestaciones de insuficiencia adrenal o ambas. Se describen sus principales síntomas clínicos, así como los resultados de las investigaciones realizadas, y se exponen los éxitos obtenidos con el tratamiento integral (medicoquirúrgico, psicosocial) en estos pacientes y la importancia de su manejo en equipo(AU)

El sindrome de Turner y el rendimiento intelectual / Turner´s syndrome and intellectual yield

Se estudia el rendimiento intelectual en 26 pacientes no hospitalizados portadores del síndrome de Turner, atendidos en el Instituto de Endocrinología y Enfermedades Metabólicas, encontrándose una alta incidencia de deficiencia mental (50 por ciento). Se relaciona el índice de rendimiento intelectual con el cariotipo de los pacientes y se comentan los resultados(AU)