Implicación ocular en pacientes con distrofia miotónica / Eye involvement in patients with myotonic dystrophy

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High intrafamilial variability in autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy: a case study.

INTRODUCTION: Autoimmune polyendocrinopathy- candidiasis-ectodermal-dystrophy syndrome (APECED) is a monogenic disease whose phenotype may reveal wide heterogeneity. The reasons of this variability still remain obscure. PATIENTS AND METHODS: Two APECED siblings with identical genotype and extremely different phenotype were compared with regard to exposure to infectious triggers, autoantibodies' profile, mechanisms of peripheral tolerance, and human leukocyte antigen (HLA) haplotype. The following infectious markers were evaluated: rubella, Epstein Barr virus, cytomegalovirus, toxoplasma, varicella zoster virus, parvovirus B19, herpes simplex virus, and parainfluenza virus. APECED-related autoantibodies were detected by indirect immunofluorescence or complement fixation or enzyme- linked immunosorbent assay or radioimmunoassay. Resistance to Fas-induced apoptosis was evaluated on peripheral blood mononuclear cells (PBMC) activated with phytohemoagglutinin, the number of TCD4+CD25+ regulatory cells (Treg) was evaluated through flow-cytometry and natural killer (NK) activity through Wallac method. Perforin (PRF1) was amplified by PCR and sequenced. RESULTS: No difference was observed between the siblings in common infectious triggers, extent of Fas-induced apoptosis, NK-cell activity and PRF1 sequence, the number of Tregs and HLA haplotypes. CONCLUSION: Although APECED is a monogenic disease, its expressivity may be extremely different even in the same family. This variability cannot be explained by common triggering infectious agents or functional alterations of mechanisms governing peripheral tolerance.

The glucose-dependent insulinotropic polypeptide receptor is overexpressed amongst GNAS1 mutation-negative somatotropinomas and drives growth hormone (GH)-promoter activity in GH3 cells.

Somatic mutations in the GNAS1 gene, encoding the α-subunit of the heterotrimeric stimulatory G protein (Gαs), occur in approximately 40% of growth hormone (GH)-secreting pituitary tumours. By altering the adenylate cyclase-cAMP-protein kinase A pathway, they unequivocally give somatotroph cells a growth advantage. Hence, the pathogenesis of somatotropinomas could be linked to anomalies in receptors coupled to the cAMP second-messenger cascade. Among them, the glucose-dependent insulinotropic polypeptide receptor (GIPR) is already known to play a primary role in the impaired cAMP-dependent cortisol secretion in patients affected by food-dependent Cushing's syndrome. In the present study, 43 somatotropinomas and 12 normal pituitary glands were investigated for GIPR expression by quantitative reverse transcriptase-polymerase chain reaction, western blotting and immunohistochemistry. Tumoural specimens were also evaluated for GNAS1 mutational status. The effect of GIPR overexpression on cAMP levels and GH transcription was evaluated in an in vitro model of somatotropinomas, the GH-secreting pituitary cell line GH3. GIPR was expressed at higher levels compared to normal pituitaries in 13 GNAS1 mutation-negative somatotropinomas. GIP stimulated adenylyl cyclase and GH-promoter activity in GIPR-transfected GH3 cells, confirming a correct coupling of GIPR to Gαs. In a proportion of acromegalic patients, GIPR overexpression appeared to be associated with a paradoxical increase in GH after an oral glucose tolerance test. Whether GIPR overexpression in acromegalic patients may be associated with this paradoxical response or more generally involved in the pathogenesis of acromegaly, as suggested by the mutually exclusive high GIPR levels and GNAS1 mutations, remains an open question.

FOXN1 mutation abrogates prenatal T-cell development in humans.

BACKGROUND: The transcription factor FOXN1 is implicated in the differentiation of thymic and skin epithelial cells, and alterations in it are responsible for the Nude/SCID phenotype. During a genetic counselling programme offered to couples at risk in a community where a high frequency of mutated FOXN1 had been documented, the identification of a human FOXN1(-/-) fetus gave the unique opportunity to study T cell development in utero. RESULTS: Total blockage of CD4(+) T cell maturation and severe impairment of CD8(+) cells were documented. Evaluation of the variable-domain ß-chain (Vß) families' usage among T lymphocytes revealed that the generation of T cell receptor (TCR) diversity occurred to some extent in the FOXN1(-/-) fetus, although it was impaired compared with the control. A few non-functional CD8(+) cells, mostly bearing TCRγδ in the absence of CD3, were found. DISCUSSION: FOXN1 is crucial for in utero T cell development in humans. The identification of a limited number of CD8(+) cells suggests an extrathymic origin for these cells, implying FOXN1-independent lymphopoiesis.

Familial temporal lobe epilepsy with psychic auras associated with a novel LGI1 mutation.

BACKGROUND: Autosomal dominant lateral temporal epilepsy (ADLTE) is characterized by focal seizures with auditory features or aphasia. Mutations in the LGI1 gene have been reported in up to 50% of ADLTE pedigrees. We report a family with temporal lobe epilepsy characterized by psychic symptoms associated with a novel LGI1 mutation. METHODS: All participants were personally interviewed and underwent neurologic examination and video-EEG recordings. LGI1 exons were sequenced by standard methods. Mutant cDNA was transfected into human embryonic kidney 293 cells; both cell lysates and media were analyzed by Western blot. In silico modeling of the Lgi1 protein EPTP domain was carried out using the structure of WD repeat protein and manually refined. RESULTS: Three affected family members were ascertained, 2 of whom had temporal epilepsy with psychic symptoms (déjà vu, fear) but no auditory or aphasic phenomena, while the third had complex partial seizures without any aura. In all patients, we found a novel LGI1 mutation, Arg407Cys, which did not hamper protein secretion in vitro. Mapping of the mutation on a 3-dimensional protein model showed that this mutation does not induce large structural rearrangements but could destabilize interactions of Lgi1 with target proteins. CONCLUSIONS: The Arg407Cys is the first mutation with no effect on Lgi1 protein secretion. The uncommon, isolated psychic symptoms associated with it suggests that ADLTE encompasses a wider range of auras of temporal origin than hitherto reported.

Calmodulin-dependent kinase II mediates vascular smooth muscle cell proliferation and is potentiated by extracellular signal regulated kinase.

Vascular smooth muscle cell (VSMC) proliferation contributes to vascular remodeling in atherosclerosis and hypertension. Calcium-dependent signaling through calcium/calmodulin-dependent kinase II (CaMKII) and ERK1/2 activation plays an important role in the regulation of VSMC proliferation by agents such as alpha-adrenergic receptor agonists. Nevertheless, how the CaMKII and ERK pathways interact in VSMCs has yet to be characterized. The aim of the present study was to clarify this interaction in response to alpha(1)-adrenergic receptor-mediated VSMC proliferation. We discovered that phenylephrine stimulation resulted in complex formation between CaMKII and ERK in a manner that facilitated phosphorylation of both protein kinases. To assess the effects of CaMKII/ERK association on VSMC proliferation, we inhibited endogenous CaMKII either pharmacologically or by adenoviral-mediated gene transfer of a kinase-inactive CaMKII mutant. Inhibition of CaMKII activation but not CaMKII autonomous activity significantly decreased formation of the CaMKII/ERK complex. On the contrary, the expression of constitutively active CaMKII enhanced VSMC growth and CaMKII/ERK association. In addressing the mechanism of this effect, we found that CaMKII could not directly phosphorylate ERK but instead enhanced Raf1 activation. By contrast, ERK interaction with CaMKII facilitated CaMKII phosphorylation and promoted its nuclear localization. Our results reveal a critical role for CaMKII in VSMC proliferation and imply that CaMKII facilitates assembly of the Raf/MEK/ERK complex and that ERK enhances CaMKII activation and influences its subcellular localization.

Thymoma-associated immunodeficiency: a syndrome characterized by severe alterations in NK, T and B-cells and progressive increase in naïve CD8+ T Cells.

Thymomas are rare tumours that sustain T-lymphopoiesis and trigger a variety of autoimmune diseases and immunodeficiencies, including a fatal hypogammaglobulinemia, namely Goods Syndrome (GS). Due to its rarity, GS has been poorly investigated and immunological features, as well as pathogenetic mechanisms underlying this syndrome, are unclear. We studied 30 thymoma patients by performing an immunological assessment, including immunophenotype and analysis of T cell repertoire (TCR). Development of GS was characterized by a progressive decrease in B, CD4 T and NK lymphocytes. These alterations paired with accumulation of CD8+CD45RA+ T cells that showed a polyclonal repertoire without expansions of specific clonotypes. GS is defined as hypogammaglobulinemia with thymoma. Here, we show for the first time that this syndrome is characterized by a severe loss of CD4+, NK and B cells. Furthermore, the accumulation of CD8+CD45RA+ T lymphocytes parallels these changes; this accumulation may have a role in determining the disease and can be used to monitor clinical stages of immunodeficiency in thymoma.

CD8+ T-cell alveolitis in familial pulmonary alveolar microlithiasis.

Pulmonary alveolar microlithiasis (PAM) is a rare diffuse lung disease characterised by the accumulation of calcium phosphate microliths within the alveoli. The causative mechanism of PAM has only recently been discovered, and involves a gene mutation of sodium phosphate co-transporter, which is expressed by alveolar epithelial cells. This mutation may have variable consequences on the clinical phenotype. However, pulmonary cell immune phenotyping in familial PAM has not previously been assessed. In the present article, the analysis of bronchoalveolar lavage fluid of two siblings with PAM diagnosis revealed a pattern of lymphocytic alveolitis with accumulation of CD8+ T-cells. The clonal complexity of this lymphocyte's population was assayed by spectratyping, which showed an oligoclonal accumulation of T-cells with a restricted variable beta T-cell receptor (TCR) gene usage. TCR analysis in peripheral blood lymphocytes revealed no abnormal patterns of T-lymphocytes. In the pulmonary alveolar microlithiasis familial cases reported, CD8-mediated maladaptive immune response may have taken place in the bronchoalveolar compartment. The relationship between this immune dysregulation and genetic background in pulmonary alveolar microlithiasis warrants further investigation.

New once-daily, highly effective rescue triple therapy after multiple Helicobacter pylori treatment failures: a pilot study.

BACKGROUND: Helicobacter pylori treatment failure is a growing problem in daily practice. AIM: To determine the efficacy of the combination of rabeprazole, levofloxacin and furazolidone as a rescue therapy. METHODS: Duodenal ulcer patients previously submitted, without success, to at least two H. pylori treatment regimens were included. Gastroscopy (urease test, histological examination and culture) and (13)C-urea breath test were performed. All patients received a combination of rabeprazole 20 mg, levofloxacin 500 mg and furazolidone 200 mg (two tablets) administered in a single dose in the morning for 10 days. Clinical examination and a new (13)C-urea breath test were performed 90 days after therapy. RESULTS: Twelve patients (eight females and four males), mean age 43 (30-58) years were included. Two patients failed to complete the treatment because of nausea and vomiting. Ten patients completed the study and took all the medications as advised. Culture was obtained in six patients: 100 and 83% of the samples were sensitive to furazolidone and levofloxacin, respectively. Per-protocol and intention-to-treat eradication rates were 100 and 83% (P = 0.019). CONCLUSIONS: the combination of rabeprazole, levofloxacin and furazolidone in a single daily dose for 10 days constitutes a highly-effective and low-cost alternative as a third-line therapy in patients infected with H. pylori.

B-cell lymphopenia and hypogammaglobulinemia in thymoma patients.

Thymic tumors represent a unique neoplastic disease associated with various immune-mediated syndromes. Immune impairment is generically recognized to be associated with thymoma. Hypogammaglobulinemia and recurrent pulmonary infections in thymoma patients define Good's syndrome. Apart from sporadic reports focusing on this topic, there is still a lack of knowledge on immune assessment and clinical sequelae in thymoma patients. The present study was performed to evaluate immunoglobulin levels, CD19(+) B lymphocytes, and CD3(+) T lymphocytes in a large series of thymoma patients from a single institution. The occurrence of recurrent severe infections was related to immunological findings to identify the possible correlation with the immunodeficiency status. Eighteen patients (eight males, ten females, mean age: 56 years, range: 19-75) with a pathological diagnosis of thymic tumor were studied. Six patients suffered from clinical recurrent pulmonary infections. Blood samples were collected to measure serum immunoglobulins and analyze immunophenotype. Low T lymphocyte number was found in 22% of the patients. T lymphocytosis was present in one patient. Panhypogammaglobulinemia was found in 4 of 18 patients (22%). Conversely B lymphopenia was a frequent finding in this series of thymoma patients (9 of 18, 50%). Five of six patients (83%) with recurrent infections had B lymphopenia, while only two (33%) had panhypogammaglobulinemia. B lymphopenia often occurred in this series of thymoma patients and was related to susceptibility to recurrent infections more than hypogammaglobulinemia. Therefore, immunophenotype has to be monitored in follow-up of thymoma patients because it may reveal significant abnormalities.

Fine analysis of the short arm of chromosome 1 in sporadic and familial pheochromocytoma.

OBJECTIVE: Despite the very recent discovery that about 25% of apparently sporadic forms of pheochromocytoma are actually due to germline mutations of RET, VHL, SDHB or SDHD genes, the genetic bases of the tumourigenesis of this type of cancer are still incompletely understood. Recent studies provided evidence that a new tumour suppressor gene, mapping on the short arm of chromosome 1, could be involved in early tumourigenesis of pheochromocytoma. DESIGN: We have performed a fine analysis of loss of heterozygosity (LOH) of this region. In particular, we have analysed 31 highly polymorphic microsatellites distributed at 3.8 Mege base (Mb) mean intervals along the short arm of the chromosome 1 in paired samples of DNA extracted from peripheral blood lymphocytes and tumour tissues. PATIENTS: The study was carried out on 38 patients with pheochromocytoma that had been grouped, by careful clinical and molecular investigation, in the following classes: 21 sporadic, five multiple endocrine neoplasia type 2 (MEN2), two type 1 neurofibromatosis (NF1), five von Hippel-Lindau (VHL), one somatic VHL mutated and four nonsyndromic familial cases. RESULTS: In 12/21 sporadic cases (57.1%), in 4/5 MEN2 (80%), 2/4 non-syndromic familial cases (50%), and in 2/2 NF1 (100%), the entire short arm was deleted, while in 6/21 sporadic (28.6%) and 1/5 MEN2 (20%) cases a partial deletion was detected. On the other hand, none of the five cases due to VHL mutation (either germline or somatic) had LOH at chromosome 1. In total, complete or partial deletion of 1p was detected in 27/38 (71%) of the cases. The most frequently deleted marker was D1S2890, which maps at 1p32.1. This region, which spans from 50 to 62 Mb from telomere, was therefore further investigated with markers located at a mean interval of 1.3 Mb in the subset of cases that showed a partial deletion of 1p. This analysis showed that a small region between 55.1 and 59.0 Mb was most frequently missing, which could therefore contain a novel pheochromocytoma locus. CONCLUSIONS: The results presented here confirm that the short arm of chromosome 1 harbours one or more genes responsible for the development of pheochromocytoma and suggest that one of them could map in a 3.9-Mb fragment between 1p32.3 and 1p32.1.

Macrophage-secreted myogenic factors: a promising tool for greatly enhancing the proliferative capacity of myoblasts in vitro and in vivo.

In this work we set out to determine if the murine macrophage J774 cell line can be used to produce myogenic growth factors. Activated J774 macrophages were grown in serum-free conditions. The macrophage-conditioned medium (MCM) was then used to treat cultures of primary myoblasts and regenerating muscle tissue, in vitro and in vivo respectively. MCM activity in vitro was tested by analyzing the expression of muscle-specific transcription factors, in parallel with the proliferation and differentiation rates of the cells. The macrophage-secreted factors greatly enhanced the proliferative potential of both rat and human primary myoblasts and were found to be highly muscle-specific. In vivo, MCM administration markedly enhanced the regenerative processes in damaged muscles. The ability to produce large amounts of macrophage-secreted myogenic factor(s) in the absence of serum holds great promise for its biochemical characterization and successive application in therapeutic protocols, both for ex vivo gene therapy and for muscle repair.

Gene transfer in skeletal muscle by systemic injection of DODAC lipopolyplexes.

Lipid-based vectors are a promising tool for gene therapy applications. Several studies have reported their use in vivo to transfect different organs. Few data, however, are available about lipid-mediated gene transfer in skeletal muscle. Here we report the initial results obtained after systemic administration of lipopolyplexes based on the DODAC cationic lipid in an animal model of muscle regeneration. In particular, we compared three routes of administration: intravenous (i.v.), intracardiac (IC) and intra-arterial (IA). Analysis of reporter gene expression (luciferase) showed that regenerating muscle is more efficiently transfected in all cases and that IA injection is by far the best approach.

Ovarian stimulation using a new highly purified urinary FSH: a prospective randomized clinical study.

The aim of this study was to determine the effectiveness of a new highly purified urinary FSH. A total of 60 in vitro-fertilization (IVF) patients, undergoing embryo transfer (ET) for the first time, were randomly allocated into two groups: Group A (n = 30). Subcutaneous administration of urinary follicle-stimulating hormone (FSH, Fostimon 75, A.M.S.A., Italy). Group B (n = 30). Subcutaneous administration of urinary follicle-stimulating hormone (FSH, Metrodin 75 HP, Serono, Italy). Statistical analysis was performed using the chi-square test, p < 0.05 was assumed as significant. This prospective randomized clinical study in an IVF-ET program showed that both drugs were equally safe and effective. Except for the number of the high quality embryos (3.16 vs 2.9; p = 0.03) the two groups did not differ in stimulation parameters or clinical pregnancy rates per attempt and per transfer. On the other hand, a mean number of 3.56 vs 2.18 embryos were cryopreserved in group A and in group B, respectively, as a result of the high number of mature oocytes and high quality embryos. When frozen embryos cycles were included, the difference in pregnancy rate became significant.

Transfection of cultured myoblasts in high serum concentration with DODAC:DOPE liposomes.

The inhibitory effect of serum is one of the main obstacles to the in vivo use of cationic liposomes as a DNA delivery system. We have found that a novel liposome formulation, DODAC:DOPE (1:1) is totally resistant to the inhibitory effects of serum for transfection of cultured myoblasts and myotubes. Transfection with a lacZ reporter gene in the presence of 95% fetal bovine serum gave up to 25% beta-gal-positive cells in C2C12 myoblasts and about six-fold less in primary human myoblasts. The lower transgene expression in primary cells does not appear to be a result of less DNA uptake but might result from differences in intracellular trafficking of the complexes. DODAC-based liposomes are unique in their resistance to serum inhibition and may therefore be valuable for the systemic delivery of genetic information to muscle and other tissues.

Duchenne phenotype with in-frame deletion removing major portion of dystrophin rod: threshold effect for deletion size?

In a 9-year-old boy with Duchenne muscular dystrophy we found a large in-frame deletion, spanning exons 10 to 53 of the dystrophin gene. The deletion removed almost all of the central rod domain of dystrophin. Using carboxyterminal dystrophin antibodies the immunohistochemical reaction was normal in all muscle fibers. In immunoblot studies we found dystrophin of abnormal size (160 kDa) and normal amount (about 100%). The immunochemical features and the reading frame deduced from DNA analysis are usually associated with Becker muscular dystrophy, but the clinical characteristics were those of the severe Duchenne phenotype. All the cases of in-frame dystrophin deletions reported so far, which involved more than 36 exons, invariably resulted in a severe phenotype. Therefore, a threshold effect for dystrophin length may be reasonably suspected. Very short dystrophin molecules might induce a severe disarray of the dystrophin network.

Condensation of plasmid DNA with polylysine improves liposome-mediated gene transfer into established and primary muscle cells.

Cationic liposomes provide a means to introduce genes into cells both ex vivo and in vivo. In the past few years their use has been described in several tissues, e.g. lungs, liver, endothelium, brain. In this study we evaluated a commercially available poly-cationic liposome formulation in delivering a reporter gene into cultured myogenic cell lines from mouse and rat, and primary fetal human myoblasts. We also examined the effect of serum on liposome-mediated transfection and designed a new procedure to enhance transfection efficiency, based on the pre-condensation of plasmid DNA with polylysine. Polylysine pre-condensation was particularly effective when transfecting the cells in the presence of serum, a finding that could be significant for in vivo transfections.