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1.
Tech Coloproctol ; 23(9): 831-842, 2019 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-31388861

RESUMEN

BACKGROUND: An organ-preserving strategy may be a valid alternative in the treatment of selected patients with rectal cancer after neoadjuvant radiotherapy. Preoperative assessment of the risk for tumor recurrence is a key component of surgical planning. The aim of the present study was to increase the current knowledge on the risk factors for tumor recurrence. METHODS: The present study included individual participant data of published studies on rectal cancer surgery. The literature was reviewed according to according to Preferred Reporting Items for Systematic Reviews and Meta-Analyses of Individual Participant Data checklist (PRISMA-IPD) guidelines. Series of patients, whose data were collected prospectively, having neoadjuvant radiotherapy followed by transanal local excision for rectal cancer were reviewed. Three independent series of univariate/multivariate binary logistic regression models were estimated for the risk of local, systemic and overall recurrence, respectively. RESULTS: We identified 15 studies, and 7 centers provided individual data on 517 patients. The multivariate analysis showed higher local and overall recurrences for ypT3 stage (OR 4.79; 95% CI 2.25-10.16 and OR 6.43 95% CI 3.33-12.42), tumor size after radiotherapy > 10 mm (OR 5.86 95% CI 2.33-14.74 and OR 3.14 95% CI 1.68-5.87), and lack of combined chemotherapy (OR 3.68 95% CI 1.78-7.62 and OR 2.09 95% CI 1.10-3.97), while ypT3 was the only factor correlated with systemic recurrence (OR 5.93). The analysis of survival curves shows that the overall survival is associated with ypT and not with cT. CONCLUSIONS: Local excision should be offered with caution after neoadjuvant chemoradiotherapy to selected patients with rectal cancers, who achieved a good response to neoadjuvant chemoradiotherapy.


Asunto(s)
Terapia Neoadyuvante/estadística & datos numéricos , Recurrencia Local de Neoplasia/etiología , Proctectomía/estadística & datos numéricos , Radioterapia Adyuvante/estadística & datos numéricos , Neoplasias del Recto/terapia , Anciano , Supervivencia sin Enfermedad , Femenino , Humanos , Masculino , Persona de Mediana Edad , Recurrencia Local de Neoplasia/mortalidad , Recurrencia Local de Neoplasia/patología , Estadificación de Neoplasias , Periodo Posoperatorio , Proctectomía/métodos , Neoplasias del Recto/mortalidad , Neoplasias del Recto/patología , Factores de Riesgo , Cirugía Endoscópica Transanal/métodos , Cirugía Endoscópica Transanal/estadística & datos numéricos , Resultado del Tratamiento
2.
Eur J Paediatr Dent ; 19(1): 67-69, 2018 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-29569457

RESUMEN

AIM: The aim of this article is to describe the use of a titanium TSME appliance for patients with allergy to resin and nickel. We aim to highlight the optimal way to avoid problems such as stomatitis and peri-labial dermatitis, which generally appear in patients who use traditional orthodontic appliances made in acrylic resin and steel. MATERIALS AND METHODS: The construction of a titanium appliance is described and a case treated with it is reported. RESULTS: The titanium TSME presented in this paper has excellent biocompatibility due to its ability to form superficial oxides, which prevent oxidation and thus corrosion. CONCLUSION: The non-allergic properties of titanium allow to propose it as an alternative in patients with a long-term history of allergic reactions to nichel.


Asunto(s)
Hipersensibilidad/prevención & control , Níquel/inmunología , Diseño de Aparato Ortodóncico , Técnica de Expansión Palatina/instrumentación , Titanio/inmunología , Materiales Biocompatibles , Niño , Humanos , Hipersensibilidad/etiología , Masculino , Ensayo de Materiales
3.
Am J Transplant ; 17(2): 420-431, 2017 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-27402017

RESUMEN

The reasons for the increased incidence of de novo anti-human leukocyte antibody (HLA) donor-specific antibodies (DSAs) observed after kidney allograft nephrectomy are not fully understood. One advocated mechanism suggests that at graft loss, DSAs are not detected in the serum because they are fixed on the nonfunctional transplant; removal of the kidney allows DSAs to then appear in the blood circulation. The aim of our study was to compare anti-HLA antibodies present in the serum and in the graft at the time of an allograft nephrectomy. Using solid-phase assays, anti-HLA antibodies were searched for in the sera of 17 kidney transplant patients undergoing allograft nephrectomy. No anti-HLA antibodies were detected in the graft if they were not also detected in the serum. Eleven of the 12 patients who had DSAs detected in their sera also had DSAs detected in the grafts. Epitopic analysis revealed that most anti-HLA antibodies detected in removed grafts were directed against the donor. In summary, our data show that all anti-HLA antibodies that were detected in grafts were also detected in the sera. These intragraft anti-HLA antibodies are mostly directed against the donor at an epitopic level but not always at an antigenic level.


Asunto(s)
Epítopos/inmunología , Rechazo de Injerto/etiología , Antígenos HLA/inmunología , Isoanticuerpos/sangre , Trasplante de Riñón/efectos adversos , Nefrectomía/efectos adversos , Donantes de Tejidos , Adulto , Alelos , Aloinjertos , Femenino , Supervivencia de Injerto , Humanos , Masculino
4.
Am J Transplant ; 16(5): 1474-9, 2016 05.
Artículo en Inglés | MEDLINE | ID: mdl-26587971

RESUMEN

There is no approved therapy for hepatitis C virus (HCV) infection after kidney transplantation, and no data regarding the use of new-generation direct antiviral agents (DAAs) have been published so far. The aims of this pilot study were to assess the efficacy and safety of an interferon-free sofosbuvir-based regimen to treat chronic HCV infection in kidney transplant recipients. Twenty-five kidney transplant recipients with chronic HCV infection were given, for 12 (n = 19) or 24 weeks (n = 6), sofosbuvir plus ribavirin (n = 3); sofosbuvir plus daclatasvir (n = 4); sofosbuvir plus simeprevir, with (n = 1) or without ribavirin (n = 6); sofosbuvir plus ledipasvir, with (n = 1) or without ribavirin (n = 9); and sofosbuvir plus pegylated-interferon plus ribavirin (n = 1). A rapid virological response, defined by undetectable viremia at week 4 after starting DAA therapy, was observed in 22 of the 25 patients (88%). At the end of therapy, HCV RNA was undetectable in all patients. At 4 and 12 weeks after completing DAA therapy, all had a sustained virological response. The tolerance to anti-HCV therapy was excellent and no adverse event was observed. A significant decrease in calcineurin inhibitor levels was observed after HCV clearance. New-generation oral DAAs are efficient and safe to treat HCV infection after kidney transplantation.


Asunto(s)
Antivirales/uso terapéutico , Supervivencia de Injerto/efectos de los fármacos , Hepacivirus/efectos de los fármacos , Hepatitis C/tratamiento farmacológico , Fallo Renal Crónico/complicaciones , Trasplante de Riñón/efectos adversos , Sofosbuvir/uso terapéutico , ADN Viral/genética , Femenino , Estudios de Seguimiento , Tasa de Filtración Glomerular , Hepacivirus/genética , Hepatitis C/virología , Humanos , Fallo Renal Crónico/cirugía , Pruebas de Función Renal , Masculino , Persona de Mediana Edad , Proyectos Piloto , Pronóstico , Factores de Riesgo , Seguridad , Carga Viral
5.
Am J Transplant ; 16(9): 2661-9, 2016 09.
Artículo en Inglés | MEDLINE | ID: mdl-26998676

RESUMEN

Little is known about the impact of posttransplant blood transfusion on the sensitization of anti-HLA antibodies and the formation of donor-specific antibodies (DSAs). The aims of our study were to determine the 1-year incidence of DSAs (assessed using a solid-phase assay) and antibody-mediated rejection (AMR) in kidney transplant patients who had or had not received a blood transfusion during the first year after transplantation. Included were 390 non-HLA-sensitized patients who had received an ABO-compatible kidney transplant and had not previously or simultaneously received a nonkidney transplant. Overall, 64% of patients received a red blood cell transfusion within the first year after transplantation, most within the first month. The overall 1-year incidence of DSAs was significantly higher in patients that had undergone transfusion (7.2% vs. 0.7% in patients with no transfusion, p < 0.0001). AMR occurred more often in the transfusion group (n = 15, 6%) compared with the nontransfusion group (n = 2, 1.4%; p = 0.04). Blood transfusion was an independent predictive factor for de novo DSA formation but not for AMR. Patients who had a transfusion and developed DSAs were more often treated with cyclosporin A (n = 10, 55.5%) rather than tacrolimus (n = 45, 19.4%; p = 0.0001). In conclusion, early posttransplant blood transfusion may increase immunological risk, especially in underimmunosuppressed patients.


Asunto(s)
Transfusión de Eritrocitos/efectos adversos , Rechazo de Injerto/epidemiología , Isoanticuerpos/sangre , Fallo Renal Crónico/cirugía , Trasplante de Riñón/efectos adversos , Donantes de Tejidos , Estudios de Casos y Controles , Femenino , Estudios de Seguimiento , Tasa de Filtración Glomerular , Rechazo de Injerto/etiología , Supervivencia de Injerto , Antígenos HLA/inmunología , Humanos , Incidencia , Isoanticuerpos/inmunología , Pruebas de Función Renal , Masculino , Persona de Mediana Edad , Pronóstico , Factores de Riesgo
7.
Am J Transplant ; 15(1): 190-9, 2015 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-25496195

RESUMEN

Pneumocystis pneumonia (PCP) in solid organ transplant (SOT) recipients becomes rare in the immediate posttransplantation period thanks to generalized prophylaxis. We aimed to identify the predictive factors for PCP in the era of universal prophylaxis and to propose a strategy for preventing PCP beyond the first year after transplantation. In a retrospective case-control study, 33 SOT cases with PCP diagnosed between 2004 and 2010 were matched with two controls each to identify risk factors for PCP by uni- and multivariate analysis. All the patients benefited from 6 months of posttransplantation trimethoprim-sulfamethoxazole prophylaxis. Most PCP in SOT patients occurred during the second year posttransplantation (33%). By univariate analysis, age, nonuse of tacrolimus, total and CD4 lymphocyte counts, gamma-globulin concentration and cytomegalovirus (CMV) infection appeared to be PCP risk factors. In the final multivariate analysis, age (adjusted odds ratio [OR] 3.7, 95% confidence interval [CI]: 1.3-10.4), CMV infection (OR: 5.2, 95% CI: 1.8-14.7) and total lymphocyte count (OR: 3.9, 95% CI: 1.4-10.7) were found to be independently associated with PCP. The second year posttransplantation appeared to be the new period of highest risk of PCP. Age, CMV viremia and lymphocytes were the most pertinent predictive criteria to evaluate the risk of PCP in clinical practice.


Asunto(s)
Profilaxis Antibiótica , Antifúngicos/uso terapéutico , Rechazo de Injerto/etiología , Trasplante de Órganos , Neumonía por Pneumocystis/etiología , Receptores de Trasplantes , Combinación Trimetoprim y Sulfametoxazol/uso terapéutico , Estudios de Casos y Controles , Citomegalovirus/patogenicidad , Infecciones por Citomegalovirus/complicaciones , Infecciones por Citomegalovirus/microbiología , Femenino , Estudios de Seguimiento , Rechazo de Injerto/diagnóstico , Rechazo de Injerto/tratamiento farmacológico , Supervivencia de Injerto , Humanos , Huésped Inmunocomprometido , Masculino , Persona de Mediana Edad , Pneumocystis carinii , Neumonía por Pneumocystis/diagnóstico , Neumonía por Pneumocystis/tratamiento farmacológico , Complicaciones Posoperatorias , Estudios Retrospectivos , Factores de Riesgo , Donantes de Tejidos
11.
Am J Transplant ; 14(4): 867-75, 2014 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-24580771

RESUMEN

Although large retrospective studies have identified the presence of donor-specific antibodies (DSAs) to be a risk factor for rejection and impaired survival after liver transplantation, the long-term predicted pathogenic potential of individual DSAs after liver transplantation remains unclear. We investigated the incidence, prevalence and consequences of DSAs in maintenance liver transplant (LT) recipients. Two hundred sixty-seven LT recipients, who had undergone transplantation at least 6 months previously and had been screened for DSAs at least twice using single-antigen bead technology, were included and tested annually for the presence of DSAs. At a median of 51 months (min-max: 6-220) after an LT, 13% of patients had DSAs. At a median of 36.5 months (min-max: 2-45) after the first screening, 9% of patients have developed de novo DSAs. The sole predictive factor for the emergence of de novo DSAs was retransplantation (OR 3.75; 95% CI 1.28-11.05, p = 0.025). Five out of 21 patients with de novo DSAs (23.8%) developed an antibody-mediated rejection. Fibrosis score was higher among patients with DSAs. In conclusion, monitoring for the development of DSAs in maintenance LT patients is useful in case of graft dysfunction and to identify patients with a high risk of developing liver fibrosis.


Asunto(s)
Rechazo de Injerto/etiología , Antígenos HLA/sangre , Isoanticuerpos/sangre , Cirrosis Hepática/etiología , Hepatopatías/cirugía , Trasplante de Hígado/efectos adversos , Adolescente , Adulto , Anciano , Femenino , Estudios de Seguimiento , Rechazo de Injerto/epidemiología , Rechazo de Injerto/mortalidad , Supervivencia de Injerto , Antígenos HLA/inmunología , Humanos , Incidencia , Isoanticuerpos/inmunología , Cirrosis Hepática/epidemiología , Cirrosis Hepática/mortalidad , Hepatopatías/complicaciones , Hepatopatías/mortalidad , Masculino , Persona de Mediana Edad , Prevalencia , Pronóstico , Estudios Prospectivos , Reoperación , Estudios Retrospectivos , Factores de Riesgo , Tasa de Supervivencia , Adulto Joven
12.
Opt Express ; 22(5): 5375-86, 2014 Mar 10.
Artículo en Inglés | MEDLINE | ID: mdl-24663877

RESUMEN

We present a study of Yb:YAG active media slabs, based on a ceramic layered structure with different doping levels. We developed a procedure allowing 3D numerical analysis of the slab optical properties as a consequence of the thermal load induced by the pump process. The simulations are compared with a set of experimental results in order to validate the procedure. These structured ceramics appear promising in appropriate geometrical configurations, and thus are intended to be applied in the construction of High Energy Diode Pumped Solid State Laser (DPSSL) systems working in high repetition-rate pulsed regimes.

13.
Nature ; 456(7221): 477-9, 2008 Nov 27.
Artículo en Inglés | MEDLINE | ID: mdl-19037310

RESUMEN

A plume of water vapour escapes from fissures crossing the south polar region of the Saturnian moon Enceladus. Tidal deformation of a thin surface crust above an internal ocean could result in tensile and compressive stresses that would affect the width of the fissures; therefore, the quantity of water vapour released at different locations in Enceladus' eccentric orbit is a crucial measurement of tidal control of venting. Here we report observations of an occultation of a star by the plume on 24 October 2007 that revealed four high-density gas jets superimposed on the background plume. The gas jet positions coincide with those of dust jets reported elsewhere inside the plume. The maximum water column density in the plume is about twice the density reported earlier. The density ratio does not agree with predictions-we should have seen less water than was observed in 2005. The ratio of the jets' bulk vertical velocities to their thermal velocities is 1.5 +/- 0.2, which supports the hypothesis that the source of the plume is liquid water, with gas accelerated to supersonic velocity in nozzle-like channels.

14.
Minerva Stomatol ; 63(6): 229-37, 2014 Jun.
Artículo en Inglés, Italiano | MEDLINE | ID: mdl-25267152

RESUMEN

AIM: Aim of the present study was to present a case report of a patient suffering from pycnodysostosis and assess how it may manifest and affect the dental/ orthodontic treatment. METHODS: An 11-year-old patient who was diagnosed with pycnodysostosis at the age of 18 months, attended the orthodontics department requiring treatment for extensive carious lesions, periodontal disease and severe crowding. RESULTS: After an accurate radiographic, clinical and orthodontic assessment of the patient taking into consideration the severity of the condition and the patient's necessities, we have formulated a treatment plan, which was accepted by both the patient and parents. We took into consideration the risks and benefits of the options available and the requests of the patient. CONCLUSION: We have decided to opt for the extraction of teeth to relieve the crowding as this was impeding good oral hygiene and hence increasing the risk of caries and periodontal disease. Such patients must be placed under an oral hygiene prevention scheme, a treatment plan must be accurately designed and the patient must be constantly motivated.


Asunto(s)
Picnodisostosis/terapia , Aparatos Activadores , Resorción Ósea , Cefalometría , Niño , Terapia Combinada , Caries Dental/etiología , Susceptibilidad a Enfermedades , Fracturas Óseas/etiología , Fracturas Espontáneas/etiología , Humanos , Masculino , Maloclusión/etiología , Maloclusión/cirugía , Ortodoncia Correctiva , Periodontitis/etiología , Picnodisostosis/complicaciones , Picnodisostosis/diagnóstico por imagen , Picnodisostosis/genética , Radiografía , Cráneo/anomalías , Extracción Dental
15.
CNS Neurosci Ther ; 30(3): e14448, 2024 03.
Artículo en Inglés | MEDLINE | ID: mdl-37718696

RESUMEN

BACKGROUND: miRNA-based strategies have recently emerged as a promising therapeutic approach in several neurodegenerative diseases. Unregulated cation influx is implicated in several cellular mechanisms underlying neural cell death during ischemia. The brain constitutively active isoform of transient receptor potential melastatin 7 (TRPM7) represents a glutamate excitotoxicity-independent pathway that significantly contributes to the pathological Ca2+ overload during ischemia. AIMS: In the light of these premises, inhibition of TRPM7 may be a reasonable strategy to reduce ischemic injury. Since TRPM7 is a putative target of miRNA135a, the aim of the present paper was to evaluate the role played by miRNA135a in cerebral ischemia. Therefore, the specific objectives of the present paper were: (1) to evaluate miR135a expression in temporoparietal cortex of ischemic rats; (2) to investigate the effect of the intracerebroventricular (icv) infusion of miR135a on ischemic damage and neurological functions; and (3) to verify whether miR135a effects may be mediated by an alteration of TRPM7 expression. METHODS: miR135a expression was evaluated by RT- PCR and FISH assay in temporoparietal cortex of ischemic rats. Ischemic volume and neurological functions were determined in rats subjected to transient middle cerebral artery occlusion (tMCAo) after miR135a intracerebroventricular perfusion. Target analysis was performed by Western blot. RESULTS: Our results demonstrated that, in brain cortex, 72 h after ischemia, miR135a expression increased, while TRPM7 expression was parallelly downregulated. Interestingly, miR135a icv perfusion strongly ameliorated the ischemic damage and improved neurological functions, and downregulated TRPM7 protein levels. CONCLUSIONS: The early prevention of TRPM7 activation is protective during brain ischemia.


Asunto(s)
Lesiones Encefálicas , Isquemia Encefálica , Canales Catiónicos TRPM , Ratas , Animales , Canales Catiónicos TRPM/genética , Canales Catiónicos TRPM/metabolismo , Isquemia Encefálica/tratamiento farmacológico , Isquemia Encefálica/metabolismo , Encéfalo/metabolismo , Infarto de la Arteria Cerebral Media
16.
Am J Transplant ; 13(8): 2179-85, 2013 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-23763583

RESUMEN

Thrombotic microangiopathy (TMA) is one of the hallmark vascular lesions of antiphospholipid syndrome nephropathy (APSN). These lesions are at high risk of recurrence after kidney transplantation. The complement pathway is thought to be active in this process. We used eculizumab to treat three consecutive kidney transplant recipients with posttransplant TMA due to APSN recurrence that was resistant to plasmapheresis and explored the complement deposition and apoptotic and vascular cell markers on the sequential transplant biopsies. Treatment with eculizumab resulted in a rapid and dramatic improvement of the graft function in all three patients and in improvement of the TMA lesions within the graft. None of these patients had TMA flares after eculizumab was withdrawn. At the time of TMA diagnosis, immunofluorescence studies revealed intense C5b-9 and C4d depositions at the endothelial cell surface of the injured vessels. Moreover, C5b-9 colocalized with vessels exhibiting a high rate of apoptotic cells. Examination of sequential biopsies during eculizumab therapy showed that TMA lesions, C4d and apoptotic markers were rapidly cleared but the C5b-9 deposits persisted for several months as a footprint of the TMA. Finally, we noticed that complement inhibition did not prevent the development of the chronic vascular changes associated with APSN. Eculizumab seems to be an efficient method for treating severe forms of posttransplant TMA due to APSN recurrence. Terminal complement inhibition does not prevent the development of chronic APSN.


Asunto(s)
Anticuerpos Monoclonales Humanizados/uso terapéutico , Síndrome Antifosfolípido/complicaciones , Apoptosis/efectos de los fármacos , Complicaciones Posoperatorias , Microangiopatías Trombóticas/prevención & control , Enfermedades Vasculares/tratamiento farmacológico , Adulto , Anticuerpos Antifosfolípidos/sangre , Síndrome Antifosfolípido/terapia , Enfermedad Crónica , Femenino , Técnica del Anticuerpo Fluorescente , Humanos , Depleción Linfocítica , Masculino , Plasmaféresis , Pronóstico , Recurrencia , Microangiopatías Trombóticas/etiología , Microangiopatías Trombóticas/patología , Enfermedades Vasculares/etiología , Enfermedades Vasculares/patología
17.
Transpl Infect Dis ; 15(3): E115-8, 2013 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-23601080

RESUMEN

Ochroconis gallopava is an emerging cause of mycosis in solid organ transplant recipients. Herein, we report a rare case of disseminated O. gallopava infection that involved lung, subcutaneous area, brain and peritoneum in a heart transplant recipient. Despite voriconazole therapy, the patient died 2 months after diagnosis.


Asunto(s)
Ascomicetos/patogenicidad , Trasplante de Corazón/efectos adversos , Micosis/diagnóstico , Micosis/patología , Antifúngicos/uso terapéutico , Ascomicetos/clasificación , Ascomicetos/aislamiento & purificación , Encéfalo/microbiología , Encéfalo/patología , Resultado Fatal , Humanos , Pulmón/microbiología , Pulmón/patología , Masculino , Persona de Mediana Edad , Micosis/tratamiento farmacológico , Micosis/microbiología , Peritoneo/microbiología , Peritoneo/patología , Pirimidinas/uso terapéutico , Triazoles/uso terapéutico , Voriconazol
18.
Nat Genet ; 19(3): 301-2, 1998 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-9662410

RESUMEN

It is generally assumed that the male:female (M:F) ratio in patients with type 1 (insulin-dependent) diabetes mellitus (IDDM) is 1. A recent survey, however, revealed that high incidence countries (mainly European) have a high M:F ratio and low incidence ones (Asian and African) have a low M:F ratio. We have now analysed the M:F ratio according to genotype at the major locus, the major histocompatibility complex (MHC; IDDM1). There are two main IDDM1 susceptibility haplotypes, HLA-DR3 and -DR4, which are present in 95% of Caucasian cases. We report here that in medium/high incidence Caucasian populations from the United States of America, United Kingdom and Sardinia (1307 cases), the bias in male incidence is largely restricted to the DR3/X category of patients (X not = DR4) with a M:F ratio of 1.7 (P=9.3x10(-7)), compared with a ratio of 1.0 in the DR4/Y category (Y;DR3). This is additional evidence for significant heterogeneity between the aetiology of 'DR4-associated' and 'DR3-associated' diabetes. We analysed linkage of type 1 diabetes to chromosome X, and as expected, most of the linkage to Xp13-p11 was in the DR3/X affected sibpair families (n=97; peak multipoint MLS at DXS1068=3.5, P=2.7x10(-4); single point MLS=4.5, P=2.7x10(-5)). This is evidence for aetiological heterogeneity at the IDDM1/MHC locus and, therefore, in the search for non-MHC loci in type 1 diabetes, conditioning of linkage data by HLA type is advised.


Asunto(s)
Diabetes Mellitus Tipo 1/genética , Ligamiento Genético , Antígeno HLA-DR3/genética , Cromosoma X , Adolescente , Adulto , Femenino , Humanos , Masculino , Caracteres Sexuales
19.
Nat Genet ; 17(3): 350-2, 1997 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-9354805

RESUMEN

The IDDM2 type 1 diabetes susceptibility locus was mapped to and identified as allelic variation at the insulin gene (INS) VNTR regulatory polymorphism. In Caucasians, INS VNTR alleles divide into two discrete size classes. Class I alleles (26 to 63 repeats) predispose in a recessive way to type 1 diabetes, while class III alleles (140 to more than 200 repeats) are dominantly protective. The protective effect may be explained by higher levels of class III VNTR-associated INS mRNA in thymus such that elevated levels of preproinsulin protein enhance immune tolerance to preproinsulin, a key autoantigen in type 1 diabetes pathogenesis. The mode of action of IDDM2 is complicated, however, by parent-of-origin effects and possible allelic heterogeneity within the two defined allele classes. We have now analysed transmission of specific VNTR alleles in 1,316 families and demonstrate that a particular class I allele does not predispose to disease when paternally inherited, suggestive of polymorphic imprinting. But this paternal effect is observed only when the father's untransmitted allele is a class III. This allelic interaction is reminiscent of epigenetic phenomena observed in plants (for example, paramutation; ref. 17) and in yeast (for example, trans-inactivation; ref. 18). If untransmitted chromosomes can have functional effects on the biological properties of transmitted chromosomes, the implications for human genetics and disease are potentially considerable.


Asunto(s)
Diabetes Mellitus Tipo 1/genética , Insulina/genética , Alelos , Estudios de Casos y Controles , Diabetes Mellitus Tipo 1/epidemiología , Femenino , Variación Genética , Genética de Población , Homocigoto , Humanos , Masculino
20.
Nat Genet ; 19(3): 297-300, 1998 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-9662409

RESUMEN

Genetic analysis of a mouse model of major histocompatability complex (MHC)-associated autoimmune type 1 (insulin-dependent) diabetes mellitus (IDDM) has shown that the disease is caused by a combination of a major effect at the MHC and at least ten other susceptibility loci elsewhere in the genome. A genome-wide scan of 93 affected sibpair families (ASP) from the UK (UK93) indicated a similar genetic basis for human type 1 diabetes, with the major genetic component at the MHC locus (IDDM1) explaining 34% of the familial clustering of the disease (lambda(s)=2.5; refs 3,4). In the present report, we have analysed a further 263 multiplex families from the same population (UK263) to provide a total UK data set of 356 ASP families (UK356). Only four regions of the genome outside IDDM1/MHC, which was still the only major locus detected, were not excluded at lambda(s)=3 and lod=-2, of which two showed evidence of linkage: chromosome 10p13-p11 (maximum lod score (MLS)=4.7, P=3x10(-6), lambda(s)=1.56) and chromosome 16q22-16q24 (MLS=3.4, P=6.5x10(-5), lambda(s)=1.6). These and other novel regions, including chromosome 14q12-q21 and chromosome 19p13-19q13, could potentially harbour disease loci but confirmation and fine mapping cannot be pursued effectively using conventional linkage analysis. Instead, more powerful linkage disequilibrium-based and haplotype mapping approaches must be used; such data is already emerging for several type 1 diabetes loci detected initially by linkage.


Asunto(s)
Diabetes Mellitus Tipo 1/genética , Adolescente , Adulto , Mapeo Cromosómico , Predisposición Genética a la Enfermedad , Humanos , Reino Unido
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