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1.
Orthod Craniofac Res ; 19(4): 222-233, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27506322

RESUMEN

OBJECTIVES: There is controversy regarding the relationship between mandibular position and alterations of the cranial base that provoke a more anterior location of the glenoid fossa. Artificially deformed skulls display marked alterations of the cranial base. This study evaluates mandibular changes as function of the morphology of the cranial base in these skulls. MATERIAL AND METHODS: A geometric morphometric study was performed on lateral cephalometric X-rays of three groups of skulls: 32 with anteroposterior deformity, 17 with circumferential deformity and 39 with no apparent deformity. RESULTS: In artificially deformed skulls, the cranial base was deformed causing the mandibular condyle to be in a more anterior position. There was a complete remodelling of the mandible involving narrowing and elongation of the mandibular ramus, rotation of the corpus of the mandible and increased vertical height of the symphysis. Forward displacement did not occur. Integration between mandible and cranial base is not altered by deformation of the skull. CONCLUSIONS: Deformity of the cranial vault exerts an influence on the mandible, supporting the theory of modular units in complete integration. This also supports the theory that mandibular prognathism is a multifactorial result and not a direct effect of displacement of the cranial base.


Asunto(s)
Cefalometría/métodos , Anomalías Craneofaciales/diagnóstico por imagen , Procesamiento de Imagen Asistido por Computador/métodos , Mandíbula/patología , Base del Cráneo/patología , Cráneo/diagnóstico por imagen , Cráneo/patología , Arqueología , Anomalías Craneofaciales/etnología , Anomalías Craneofaciales/etiología , Historia Antigua , Humanos , Indígenas Sudamericanos/etnología , Masculino , Mandíbula/crecimiento & desarrollo , Cóndilo Mandibular/patología , Perú/etnología , Análisis de Componente Principal , Prognatismo/etiología , Radiografía/métodos , Cráneo/crecimiento & desarrollo , Base del Cráneo/crecimiento & desarrollo
2.
Biomaterials ; 76: 313-20, 2016 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-26561930

RESUMEN

Metals and ceramics are commonly used in orthopaedics, dentistry and other load bearing applications. However, the use of ceramic matrix composites reinforced with biocompatible metals for heavy load-bearing hard tissue replacement applications has not previously been reported. In order to improve the reliability and the mechanical properties of biomedical implants, new zirconia-Nb composites have been recently developed. The aim of this study was to investigate the biological tolerance of these new zirconia/Nb biocermets implants with both in vitro and in vivo approaches. At first, human bone marrow derived mesenchymal stem cells were cultured on sintered biocermet discs with polished surfaces and were compared with responses to niobium metal. In vitro, the biocermets showed no deleterious effect on cell proliferation, extra-cellular matrix production or on cell morphology. Furthermore, the biocermet showed a higher percentage of cell proliferation than Nb metal. On the other hand, the bone response to these new zirconia/Nb biocermets was studied. Cylinders of biocermets, as well as commercially Nb rod were implanted in the tibiae of New Zealand white rabbits. All the animals were euthanatized after 6 months. The specimens were processed to obtain thin ground sections. The slides were observed in normal transmitted light microscope. A newly formed bone was observed in close contact with material surfaces. No inflamed or multinucleated cells were present. This study concluded that zirconia/Nb composites are biocompatible and osteoconductive. The ceramic-metal composite has even better osteointegration ability than pure Nb. In conclusion, zirconia-Nb biocermet is suitable for heavy load-bearing hard tissue replacement from the point of view of both mechanical properties and biocompatibility.


Asunto(s)
Materiales Biocompatibles , Niobio , Circonio , Animales , Células Cultivadas , Humanos , Técnicas In Vitro , Células Madre Mesenquimatosas/citología , Conejos
3.
Rev. argent. endocrinol. metab ; 52(3): 120-128, jun. 2015. ilus, tab
Artículo en Inglés | LILACS | ID: biblio-957923

RESUMEN

Thyrotropinomas or TSHomas are functioning pituitary adenomas that produce central hyperthyroidism and are often detected at macroadenoma stage, with the expected mass effects of large pituitary tumors. We report the long-term outcome of two thyrotropinomas, and discuss the treatment options adopted and available for these patients. Our first patient was seen 4 years after diagnosis of hyperthyroidism and two years after pituitary surgery, with persistent disease. The second subject was diagnosed soon after the detection of a symptomatic pituitary mass with extrasellar extension, with the corresponding clinical and laboratory workup. None of them was cured by surgery alone; both were treated with somatostatin analogs and radiotherapy with a clear improvement of their condition.


Los tirotropinomas son raros adenomas hipofisarios funcionantes, que producen hipertiroidismo central y, como se suelen detectar en el estadio de macroadenomas, con los signos de masa correspondientes. Presentamos la evolución a largo plazo de dos tirotropinomas para analizar las opciones terapéuticas adoptadas y disponibles para estos pacientes. Nuestro primer caso fue visto 4 años después del diagnóstico de hipertiroidismo, y dos años pos cirugía pituitaria, con enfermedad persistente. El segundo sujeto fue diagnosticado poco después de la detección de una masa hipofisaria, con expansión extraselar sintomática, mediante la evaluación clínico endocrionológica y de laboratorio pertinente. Ninguno de los dos fue curado por la cirugía solamente; ambos fueron tratados con análogos de somatostatina y radioterapia, con un claro beneficio clínico, imagenológico y bioquímico.

4.
J Invertebr Pathol ; 113(3): 214-9, 2013 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-23583807

RESUMEN

A proliferative disease, usually referred as disseminated neoplasia (DN), shows high prevalence in some cockle Cerastoderma edule beds of Galicia (NW Spain). Chromosome counts, examination of chromosome morphology, DNA quantification by flow cytometry and estimation of apoptosis frequency by TUNEL assay and flow cytometry were performed in cockles with different DN severity. Metaphases obtained from gills of DN-affected cockles displayed a chromosome number ranging from 41 to 145, while normal number is 38; changes in chromosome morphology were also evident, with numerous microchromosomes occurring. Haemolymph flow cytometry analysis revealed difference in DNA content between healthy and DN-affected cockles. Aneuploid peaks ranged from 1.3n to 8.9n. Apoptosis frequency was determined on histological sections (TUNEL assay) and haemolymph samples (flow cytometry). Both techniques revealed neoplastic cells in apoptosis. The higher DN severity, the lower the percentage of apoptotic cells. According to flow cytometry results, the negative association between DN severity and apoptosis frequency only affected the neoplastic cells, whereas DN did not significantly affect the percentage of apoptotic hyalinocytes or apoptotic granulocytes.


Asunto(s)
Apoptosis , Cardiidae/genética , Ploidias , Animales , Cardiidae/citología , Aberraciones Cromosómicas , Citometría de Flujo , Hemolinfa/química , Etiquetado Corte-Fin in Situ
5.
Rev. argent. endocrinol. metab ; 48(1): 34-37, ene.-mar. 2011. tab
Artículo en Español | LILACS | ID: lil-641989

RESUMEN

La variada clínica de la enfermedad hipotalámica (convulsiones, hidrocefalia, hipopituitarismo, alteraciones del apetito, el sueño y la temperatura corporal) incluye también los desórdenes regulatorios de la tonicidad y el volumen del líquido extracelular, debidos a la disrupción de la secreción de ADH (hormona antidiurética, vasopresina) y/o del mecanismo de la sed. Se presenta un caso de un paciente operado de un craneofaringioma, que desarrolló diabetes insípida adípsica, que ilustra la alteración conjunta de los mecanismos regulatorios del balance hídrico. Los autores declaran no poseer conflictos de interés.


The varied manifestations of hypothalamic disease (seizures, hydrocephalus, hypopytuitarism, altered appetite, sleep and body temperature regulation) also include plasma tonicity and extracellular volume regulation disorders, due to the disruption of ADH (antidiuretic hormone, vasopressin) secretion and/ or thirst mechanisms. We report the case of a patient operated on craniopharyngioma, who developed adipsic diabetes insipidus which illustrates the combined alterations of the mechanisms regulating water balance. No financial conflicts of interest exist.

6.
Diabetologia ; 53(6): 1184-9, 2010 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-20221823

RESUMEN

AIMS/HYPOTHESIS: IMT504 is an oligonucleotide that promotes tissue repair in bone injury and neuropathic pain models by stimulating progenitor cells. Here we evaluated the effect of IMT504 on the recovery of islet function in a streptozotocin (STZ)-induced model of diabetes in the rat. METHODS: Male Sprague-Dawley rats were injected with STZ (60 mg/kg, i.p., day 1) or citrate buffer (Control). Animals with glycaemia between 11 and 20 mmol/l on day 4 were injected with IMT504 (4 mg/animal in saline, s.c., STZ-IMT504) or with saline (STZ-Saline) for 10 days. Glycaemia and water and food intake were recorded for 33 days. Intraperitoneal glucose tolerance tests (IPGTTs) were performed on day 30. On day 35, overnight-fasted animals were killed and blood samples and pancreases collected for hormonal and histological studies. A second group of STZ-IMT504 rats was killed, together with Control and STZ-Saline rats, after two consecutive days of blood glucose decreases after the beginning of IMT504 treatment. Pancreases were collected and proliferating cell nuclear antigen (PCNA), nestin and neurogenin 3 (NGN3) detected by immunohistochemistry. RESULTS: IMT504 greatly improved blood glucose and food and water intakes in STZ-IMT504 rats by day 8, as well as IPGTTs on day 30. Significant increases in islet number and beta cell content were observed in STZ-IMT504 rats (day 33). Furthermore, after two to five IMT504 injections, blood glucose decreased, and an increase in pancreatic nestin (mainly in endothelial cells), PCNA and NGN3 production (in islets) was observed in STZ-IMT504 rats. CONCLUSIONS/INTERPRETATION: IMT504 induced a marked recovery of STZ-induced diabetes that correlated with early production of progenitor cell markers, such as nestin and NGN3.


Asunto(s)
Factores de Transcripción con Motivo Hélice-Asa-Hélice Básico/metabolismo , Glucemia/metabolismo , Diabetes Mellitus Experimental/terapia , Células Secretoras de Insulina/metabolismo , Proteínas de Filamentos Intermediarios/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Oligodesoxirribonucleótidos/uso terapéutico , Análisis de Varianza , Animales , Recuento de Células , Diabetes Mellitus Experimental/metabolismo , Ingestión de Alimentos , Inmunohistoquímica , Inmunomodulación , Resistencia a la Insulina , Masculino , Nestina , Oligodesoxirribonucleótidos/metabolismo , Páncreas/metabolismo , Radioinmunoensayo , Ratas , Ratas Sprague-Dawley , Células Madre , Resultado del Tratamiento
7.
Differentiation ; 79(2): 93-101, 2010 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-19926393

RESUMEN

Bone marrow mesenchymal stromal cells (BM-MSCs) with regenerative potential have been identified in heart. Whether these cells become new cardiac lineage cells by phenomena of transdifferentiation or fusion is also being investigated. Although, these mechanisms give cardiomyocytes, it has to be considered that MSCs transplantation could carry out ossification and calcification processes. An alternative might be the use of myocytes; however, the problem is the arrythmia. For those reasons, is that we investigated how to obtain cardiomyocyte-like cells from human MSCs (hMSCs). The aim of the present work was to evaluate a nuclear reprogramming of the hMSCs by a neonatal rat cardiomyocytes extract (EX) using Streptolysin O (SLO) treatment. hMSCs treated with 57.5ng/ml SLO presented ball-like, stick-like and myotube-like morphology. In the absence of cardiomyogenic stimuli, hMSCs expressed markers of cardiac phenotype-like sarcomeric alpha-actinin, connexin-43 and GATA-4. However, when hMSCs were treated with SLO+EX or 10 microM of 5-azacytidine (5-AZA), the expression of these markers were significantly increased and furthermore, expressed SERCA-2, cardiac Troponin I, beta-MyHC, desmin, MLC-2a and MLC-2v thus showing the phenotype of mature cardiomyocytes. PCR analysis showed that cardiomyocyte-related genes, such as beta1-adrenergic receptor (beta1-AR), MLC-2a and cardiac Troponin T, were expressed after SLO+EX treatment like with 5-AZA. We concluded that the extract of neonatal rat cardiomyocytes could promote a nuclear modification of hMSCs to cardiomyogenic-like cells differentiation. Since the 5-AZA treatment appears to be genotoxic and taking into account the obtained results, the nuclear reprogramming by cell extract may be an approach leading to the identification of soluble factors that drives the reprogramming.


Asunto(s)
Células de la Médula Ósea/citología , Células Madre Mesenquimatosas/citología , Miocitos Cardíacos/metabolismo , Adolescente , Adulto , Animales , Azacitidina/farmacología , Células de la Médula Ósea/metabolismo , Diferenciación Celular , Linaje de la Célula , Células Cultivadas , Niño , Femenino , Humanos , Masculino , Células Madre Mesenquimatosas/metabolismo , Miocitos Cardíacos/citología , Ratas
8.
Eur J Dent Educ ; 12(4): 219-24, 2008 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-19021728

RESUMEN

The curricula of dental faculties in many countries of the European Union can be described as odontological. The faculties of some of the countries who have become and are becoming members of the European Community have traditionally educated dentists in the stomatological tradition. In 1987, the Spanish dental education system initiated movement from the stomatological model to the odontological. Both models have their respective strengths and weaknesses. This study surveyed professors and senior lecturers in Spain's public dental faculties to assess their perspectives on 10 items related to the tension between the odontological and the stomatological approach to preparing dentists. Amongst other things, the results of the study indicate that the respondents believe the odontological model, with its emphasis on strengthening technical qualifications, may not prepare individuals for dental practice better than the stomatology tradition; and that the odontological model results in the loss of the strength of the stomatological model, that is, the strong foundation in clinical medicine. The suggestion is advanced that European dental educators consider revising the odontology curriculum to strengthen the education of dental students in clinical medicine. A curriculum in which dental and medical students share the first 3 years of study could accomplish this. It is further suggested that subsequent years in the curriculum be flexible enough for students to earn degrees in both dentistry and medicine, if desired. Such an approach is not inconsistent with the accepted profile and competencies of the European dentist.


Asunto(s)
Actitud del Personal de Salud , Odontología , Docentes de Odontología , Medicina Oral , Terminología como Asunto , Competencia Clínica , Estudios Transversales , Curriculum , Educación en Odontología , Educación Médica , Unión Europea , Humanos , Medicina Oral/educación , Odontología en Salud Pública/educación , España , Encuestas y Cuestionarios , Tecnología Odontológica/educación
9.
J Hered ; 96(1): 52-8, 2005.
Artículo en Inglés | MEDLINE | ID: mdl-15598716

RESUMEN

Metaphase chromosomes of the scallop Hinnites distortus were analyzed using Giemsa staining, chromosome measurements, silver staining, one- and two-color fluorescent in situ hybridization (FISH) ribosomal DNA (rDNA) probes, and 4',6-diamidino-2-phenylindole (DAPI) banding compatible with in situ hybridization. The karyotype (2n = 38) consists of three submetacentric-metacentric, one submetacentric, one subtelocentric-submetacentric, and 14 subtelocentric pairs. The 18S-28S rDNA maps at the centromeric level of two subtelocentric pairs, but not more than two nucleolus organizer region (NOR)-bearing chromosomes were transcriptionally active. The 5S rDNA seems to show a conventional tandem arrangement with a repeat unit of about 450 bp and it maps at the pericentromeric region of the long arm of one subtelocentric pair. Two-color FISH demonstrated that 18S-28S rDNA and 5S rDNA are not syntenic. Sequential FISH/Giemsa staining and subsequent chromosome pairing allow us to propose that pairs 9 and 12 carry the 18S-28S rDNA and pair 13 carries the 5S rDNA. All chromosomes are characterized as containing constitutive heterochromatin at the centromeric region. The data provided are the first contribution toward construction of the molecular karyotype of H. distortus and will be useful in assessing evolutionary relationships within scallops.


Asunto(s)
Genes de ARNr , Moluscos/genética , Animales , Mapeo Cromosómico/métodos , ADN Ribosómico/análisis , Heterocromatina/química , Hibridación Fluorescente in Situ/métodos , Cariotipificación , Metafase , Reacción en Cadena de la Polimerasa
10.
Mar Biotechnol (NY) ; 4(5): 495-502, 2002 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-14961243

RESUMEN

Polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis of the ribosomal DNA region spanning the 5.8S RNA gene and the 2 flanking internal transcribed spacers (ITSs) was performed to establish DNA-based molecular markers for the identification of the scallops Aequipecten opercularis, Chlamys distorta, Mimachlamys varia, and Pecten maximus. Chlamys distorta was distinguished simply by ITS size. Species-specific restriction patterns were found with the restriction enzyme AluI, and also with SmaI for A. opercularis and M. varia. When ITS sizes and the RFLPs obtained with SmaI were combined, the 4 scallops were also differentiated. Additional species-specific RFLPs were revealed after ITS-2 PCR amplification and subsequent digestion with Hsp92II. Using this marker, canned scallops were identified. Thus this work provides a simple, reliable, and rapid method for the identification of scallops that can be used when species-specific morphologic characteristics are removed or when specimens are small in size.

11.
J Oral Rehabil ; 28(10): 930-6, 2001 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-11737564

RESUMEN

We studied the dental contact section of the chewing cycle, the most important section in terms of function (as it governs the effectiveness of food trituration). Specifically, we determined closing phase dental contact distance and lateral path inclination in a sample of healthy subjects, and investigated possible relationships between these variables and Ahlgren chewing cycle type. The chewing cycle was characterized in 63 healthy subjects by frontal plane kinesiography. In all cases kinesiographs were obtained for both right- and left-side chewing, with chewing gum as bolus. In all cases we determined closing phase dental contact distance, lateral path inclination and Ahlgren chewing cycle type. Most subjects (84%) showed 'normal' chewing cycles (Ahlgren types I-IV); inverted, contralateral and irregular cycles (types V-VII) were infrequent. Mean dental contact distance was 0.9 mm for right-side chewing and 1.2 mm for left-side chewing. Mean lateral path inclination was 35 degrees for right-side chewing and 37 degrees for left-side chewing. Normal chewing cycles are generally bilateral, whereas abnormal chewing cycles are never bilateral. Border movement distance does not differ in any consistent way between 'chopping' and 'grinding' chewing cycle types. Closing phase dental contact distance showed a significant positive correlation with lateral path inclination.


Asunto(s)
Oclusión Dental , Masticación/fisiología , Adulto , Femenino , Humanos , Registro de la Relación Maxilomandibular , Magnetismo , Masculino , Mandíbula/fisiología , Movimiento
12.
Eur J Prosthodont Restor Dent ; 9(1): 9-12, 2001 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-11695135

RESUMEN

The present case report describes a procedure for obtaining the master impression and the maxillo-mandibular relationship for the definitive prosthesis in a maxillectomy patient. After casting the metal framework, a visible-light-cured tray resin was spread over the resin retention grid and gradually cured. Modelling compound was extended over the resin with functional movements, and finally the margins of the defect were sealed with a dental impression wax. A column of light-cured resin was constructed from the lower face of the resin/compound/wax structure to the opposing dental arch. This column permitted recording of the maxillo-mandibular relationship.


Asunto(s)
Técnica de Impresión Dental , Diseño de Prótesis Dental , Registro de la Relación Maxilomandibular/métodos , Maxilar/cirugía , Obturadores Palatinos , Resinas Acrílicas , Aleaciones Dentales , Articuladores Dentales , Revestimiento para Colado Dental , Abrazadera Dental , Materiales de Impresión Dental , Diseño de Dentadura , Dentadura Parcial Removible , Humanos , Registro de la Relación Maxilomandibular/instrumentación , Masculino , Ajuste de Prótesis , Propiedades de Superficie , Ceras
13.
Chromosome Res ; 9(6): 495-505, 2001.
Artículo en Inglés | MEDLINE | ID: mdl-11592484

RESUMEN

The 5S ribosomal DNA of the mussels Mytilus galloprovincialis and M. edulis was amplified by PCR using contiguous primers. The most general 5S rDNA amplification pattern consisted of several products in both mussels. Two main PCR products of about 250 bp and 760 bp were cloned and sequenced, revealing two classes of 5S rDNA units. These were characterized as containing an identical coding region of 119 bp but with highly divergent spacers. Clones of each unit type exhibited minimal differences except those of the large unit of M. edulis. The sequences analysed of the two mussels possess the same coding region and only six fixed base changes on the spacers. FISH, carried out with specific probes, consistently showed hybridization signals on the largest metacentric pair (two differentiated sites) and with variable frequency on two other metacentric pairs (one site on each pair). Differences in the 5S rDNA distribution between both mussels were not found. In M. edulis, chromosomes carrying 18S-28S rDNA were also identified by FISH. These correspond to two submetacentric-subtelocentric pairs, as was previously reported in M. galloprovincialis, demonstrating that the two rDNA multigene families are located on different chromosome pairs in these mussels.


Asunto(s)
Bivalvos/genética , ADN Ribosómico/genética , Animales , Secuencia de Bases , Mapeo Cromosómico , Cartilla de ADN/química , Variación Genética , Hibridación Fluorescente in Situ , Metafase/genética , Datos de Secuencia Molecular , Reacción en Cadena de la Polimerasa , ARN Ribosómico 18S/genética , ARN Ribosómico 28S/genética , Homología de Secuencia de Ácido Nucleico , Especificidad de la Especie
14.
J Prosthet Dent ; 84(3): 280-8, 2000 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-11005900

RESUMEN

STATEMENT OF PROBLEM: Er:YAG (erbium-doped yttrium aluminium garnet) lasers have been effective in the removal of dental tissues. It has been suggested that they are also useful for preparing dental surfaces for adhesion, but results to date have been controversial. PURPOSE: This study compared the tensile strength of bracket-tooth bonds obtained after preparation of the surface for adhesion (dentin or enamel) by conventional acid-etching or by Er:YAG laser etching and investigated microstructure of resin-tooth interfaces using the 2 procedures. MATERIAL AND METHODS: Eighty healthy human premolars were used. Brackets were cemented to acid-etched enamel, laser-etched enamel, acid-etched dentin, or laser-etched dentin (20 teeth per group). Dentin was previously exposed using a high-speed handpiece. Acid-etching was with 37% orthophosphoric acid (15 seconds for enamel, 5 seconds for dentin). Laser etching was with Er:YAG laser (four 200 mJ pulses per second for enamel; four 160 mJ pulses per second for dentin). Brackets were bonded with autocuring resin paste, having first applied a primer (dentin only) and then light-cured bonding resin. Tensile strength was determined with a universal testing machine. Data were analyzed with 2-way ANOVA and subsequent t test with Bonferroni correction. Fracture patterns were compared by the Wilcoxon test with Bonferroni correction. For SEM studies of the resin-tooth interface, a total of 12 premolars were used (3 for each tissue per treatment combination). RESULTS: Mean tensile bond strength for acid-etched enamel (14.05 +/- 5.03 MPa) was significantly higher (P<.05) than for laser-etched enamel (8.45 +/- 3.07 MPa), and significantly higher (P<.05) for acid-etched dentin (4.70 +/- 2.50 MPa) than laser-etched dentin (2.48 +/- 1.94 MPa). Bond failure after laser etching was due to microcohesive fracture of tooth tissue. SEM studies of both resin-enamel and resin-dentin interfaces indicated extensive subsurface fissuring after laser etching. CONCLUSION: Adhesion to dental hard tissues after Er:YAG laser etching is inferior to that obtained after conventional acid etching. Enamel and dentin surfaces prepared by Er:YAG laser etching show extensive subsurface fissuring that is unfavorable to adhesion.


Asunto(s)
Recubrimiento Dental Adhesivo , Esmalte Dental/efectos de la radiación , Dentina/efectos de la radiación , Rayos Láser , Grabado Ácido Dental , Análisis de Varianza , Esmalte Dental/efectos de los fármacos , Dentina/efectos de los fármacos , Humanos , Microscopía Electrónica de Rastreo , Soportes Ortodóncicos , Cementos de Resina , Estadísticas no Paramétricas , Propiedades de Superficie/efectos de los fármacos , Propiedades de Superficie/efectos de la radiación , Resistencia a la Tracción
15.
Artículo en Inglés | MEDLINE | ID: mdl-11799747

RESUMEN

The length of the silent period (SP) has been subject of extensive researches and its use has been established for the diagnosis of dysfunctional individuals. Because of its great variability we should be cautious about its assessment. This study is aimed to find the normal values taken in symptomless subjects using a commercial/medical recording system, designed for clinical use. Thirty-six readings of the SP have been taken causing a chin tap. The assessment of the motor dysfunction and the subsequent depressed activity gave the result of 32.37 ms (SD = 19.47, ranged from 15 to 110). This is slightly more extended than the results described by the majority of the Authors.


Asunto(s)
Músculo Masetero/fisiología , Periodo Refractario Electrofisiológico/fisiología , Adulto , Mentón , Electromiografía , Femenino , Humanos , Masculino , Músculo Masetero/inervación , Neuronas Motoras/fisiología , Percusión , Reflejo/fisiología , Procesamiento de Señales Asistido por Computador , Factores de Tiempo
16.
J Prosthet Dent ; 80(5): 527-32, 1998 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-9813801

RESUMEN

STATEMENT OF PROBLEM: The survival of pulpless teeth restored with a post and core system is a controversial issue. PURPOSE: This study compared the fracture resistance of 2 types of restorations: teeth restored with prefabricated carbon-fiber posts and composite cores to cast dowel-core restored teeth. MATERIAL AND METHODS: A total of 44 recently extracted sound premolars were randomly distributed into 2 equal groups: group I, restored with prefabricated carbon-fiber post and a composite core; and group II, with custom-cast type III gold alloy post and cores. The size and shape of the posts were identical in the 2 groups. All teeth were fully covered with a nonprecious cast crown. Fracture resistance was measured by applying a point force at 45 degrees to the long angle of the tooth. RESULTS: Mean fracture threshold was 103.7 +/- 53.1 kg for group I versus 202.7 +/- 125.0 kg for group II (differences significant with P = .003). In group II, however, fracture nearly always affected the tooth itself, whereas in group I, the post-core nearly always failed first. CONCLUSIONS: Significantly higher fracture thresholds were recorded for the cast post and core group. Teeth restored with cast posts typically showed fracture of the tooth, although at loads rarely occurring clinically.


Asunto(s)
Carbono , Resinas Compuestas , Materiales Dentales , Fracaso de la Restauración Dental , Técnica de Perno Muñón , Diente no Vital/rehabilitación , Adolescente , Diente Premolar , Fibra de Carbono , Aleaciones de Cromo , Coronas , Aleaciones de Oro , Humanos , Técnicas In Vitro , Técnica de Perno Muñón/estadística & datos numéricos , Estadísticas no Paramétricas
17.
Hereditas ; 128(3): 189-94, 1998.
Artículo en Inglés | MEDLINE | ID: mdl-9760868

RESUMEN

In bivalve molluscs, NOR analysis was carried out by silver staining, and extensive intra- and interindividual differences in the apparent number of NORs were reported. In this work, we determine the physical mapping of 18S and 28S ribosomal genes of the mussel M. galloprovincialis by fluorescence in situ hybridization (FISH). We also apply silver staining to the same individuals in order to determine if structural changes are involved in the heteromorphism detected by this technique. Our results show that rDNA loci map on the telomeric region of the long arm of two submetacentric-subtelocentric chromosome pairs. In addition to variations in NOR expression, we found some cases of structural variations that affect the number of rDNA loci between individuals and the location of the rDNA locus between the cells of the individual. We suggest that FISH should be applied to other bivalves to assess the variation of rDNA loci and undertake more accurate interspecific comparisons.


Asunto(s)
Bivalvos/genética , Mapeo Cromosómico , ARN Ribosómico 18S/genética , ARN Ribosómico 28S/genética , Animales , Hibridación Fluorescente in Situ , Tinción con Nitrato de Plata
18.
Genes Genet Syst ; 73(4): 193-200, 1998 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-9880917

RESUMEN

The chromosomes of the queen scallop Aequipecten opercularis were studied using conventional Giemsa staining, chromosome measurements, C-banding, silver staining, and fluorescent in situ hybridization (FISH) with 18S-28S rDNA and 5S rDNA probes. The karyotype (2n = 26) consists of large metacentric (pairs 1 and 2), telocentric (pairs 3, 4, 5, 6, 7, 8, and 9), and small metacentric chromosomes (pairs 10, 11, 12, and 13). The C-bands observed can be described as major and minor C-bands which are differentiated according to the intensity of the fluorescence and the frequency of the detection. Major C-bands were found on the long arm of the chromosome pairs 6, 7, 8, and 9 in an intercalary or subterminal position. Minor C-bands were located in the centromeric region in all chromosomes of the complement and also on one arm of pairs 12 and 13 in a terminal position. Silver spots were detected on the telomere of the long arms of one or two chromosomes of pair 7 in every case, although in two individuals up to four additional silver spots were detected. These were located on pairs 8 and 9 in the same position as the C-bands. 18S-28S ribosomal genes were found by FISH on the long arm of chromosome pair 7.5S ribosomal genes were located subterminally on one arm of metacentric pair 1, but two sites were differentiated in the case of elongated chromosomes. The results obtained allow for the identification of at least six different chromosome pairs in A. opercularis and contribute to the construction of an idiogram that is suitable for gene mapping and establishing accurate interspecific comparisons in scallops.


Asunto(s)
Hibridación Fluorescente in Situ , Moluscos/genética , Coloración y Etiquetado/métodos , Animales , ADN Ribosómico/análisis , Heterocromatina , Cariotipificación , ARN Ribosómico 18S/análisis , ARN Ribosómico 28S/análisis , ARN Ribosómico 5S/análisis , Tinción con Nitrato de Plata
19.
Medicina (B Aires) ; 57(5): 535-40, 1997.
Artículo en Español | MEDLINE | ID: mdl-9674221

RESUMEN

The objective of this study is: a) to determine if there is a relationship between memory complaints and depression and b) to compare actual verbal memory and memory complaints in depressed elderly patients and normal elderly individuals. The California Verbal Learning test (CVLT) was applied to measure memory performance. A questionnaire was used to evaluate complaints about memory. Depression was measured by the Beck Depression Inventory (BDI). The results show that depressive patients do not have deficits in verbal memory compared with normal aging individuals. There is an association between memory complaints and depressive symptoms. The depressive patients are significantly superior to the normal persons in memory complaints and depressive symptoms. The two groups are not different in objective measures of memory and learning tasks.


Asunto(s)
Trastorno Depresivo/complicaciones , Trastornos de la Memoria/complicaciones , Anciano , Trastorno Depresivo/diagnóstico , Femenino , Humanos , Masculino , Trastornos de la Memoria/diagnóstico , Encuestas y Cuestionarios
20.
Rev. neurol. argent ; 20(2): 49-54, mayo 1995. ilus, tab
Artículo en Español | BINACIS | ID: bin-23654

RESUMEN

En esta investigación se examina si el rendimiento intelectual de los ancianos sanos es diferente del observado en enfermos con Parkinson y con Alzheimer. Los tres grupos eran similares en edad y educación. La Escala de Inteligencia Wechsler para Adultos-Revisada (WAIS-R), adaptada y con normas para la población argentina, fue administrada individualmente. Las personas ancianas sanas y los enfermos con Parkinson tuvieron el mismo nivel de rendimiento en todos los subtests. Los pacientes con Alzheimer mostraron un rendimiento mucho más bajo que los otros dos grupos. El descenso es menos marcado en la parte verbal que en la ejecución, la cual requiere velocidad, habilidad motriz y memoria. Se recomienda que ante la sospecha de una enfermedad de Alzheimer se calcule, aproximadamente, el rendimiento probable del enfermo antes del comienzo de su enfermedad y que se observe si todos los subtests están marcadamente descendidos con respecto a lo esperable (AU)


Asunto(s)
Estudio Comparativo , Humanos , Masculino , Femenino , Persona de Mediana Edad , Anciano , Trastornos del Conocimiento/diagnóstico , Escalas de Wechsler/estadística & datos numéricos , Enfermedad de Alzheimer/psicología , Enfermedad de Parkinson/psicología , Trastornos del Conocimiento/etiología , Pruebas Neuropsicológicas/estadística & datos numéricos , Escalas de Wechsler/normas , Enfermedad de Alzheimer/diagnóstico , Enfermedad de Parkinson/diagnóstico , Demencia/psicología
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