RESUMEN
AIM: Constitutive release of NO blunts intrinsic and stimulated contractile activity in cerebral arteries (CA). Here, we explored whether phosphorylation and expression levels of the PKG-sensitive, leucine zipper positive (LZ+ ) splice variants of the regulatory subunit of myosin phosphatase (MYPT1) are involved and whether its expression is associated with higher cGMP sensitivity. METHODS: Vascular contractility was investigated by wire myography. Phosphorylation of MYPT1 was determined by Western blotting. RESULTS: Constitutive phosphorylation of MYPT1-T696 and T853 was lower and that of S695 and S668 was higher in cerebral arteries from the circulus arteriosus (CA-w) than in femoral arteries (FA), while total MYPT1 expression was not different. In CA-w but not in FA, L-NAME lowered phosphorylation of S695/S668 and increased phosphorylation of T696/T853 and of MLC20 -S19, plus basal tone. The increase in basal tone was attenuated in CA-w and basilar arteries (BA) from heterozygous MYPT1-T696A/+ mice. Compared to FA, expression of the LZ+ -isoform was ~2-fold higher in CA-w coincident with a higher sensitivity to DEA-NONOate, cinaciguat and Y27632 in BA and 8-Br-cGMP (1 µmol/L) in pre-constricted (pCa 6.1) α-toxin permeabilized CAs. In contrast, 6-Bnz-cAMP (10 µmol/L) relaxed BA and FA similarly by ~80%. CONCLUSION: Our results indicate that (i) regulation of the intrinsic contractile activity in CA involves phosphorylation of MYPT1 at T696 and S695/S668, (ii) the higher NO/cGMP/PKG sensitivity of CAs can be ascribed to the higher expression level of the LZ+ -MYPT1 isoform and (iii) relaxation by cAMP/PKA pathway is less dependent on the expression level of the LZ+ splice variants of MYPT1.
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Círculo Arterial Cerebral/enzimología , GMP Cíclico/metabolismo , Arteria Femoral/enzimología , Fosfatasa de Miosina de Cadena Ligera/metabolismo , Óxido Nítrico/metabolismo , Vasoconstricción , Vasodilatación , Empalme Alternativo , Animales , Círculo Arterial Cerebral/efectos de los fármacos , Proteínas Quinasas Dependientes de GMP Cíclico/metabolismo , Arteria Femoral/efectos de los fármacos , Masculino , Ratones Endogámicos C57BL , Ratones Noqueados , Fosfatasa de Miosina de Cadena Ligera/deficiencia , Fosfatasa de Miosina de Cadena Ligera/genética , Fosforilación , Sistemas de Mensajero Secundario , Vasoconstricción/efectos de los fármacos , Vasoconstrictores/farmacología , Vasodilatación/efectos de los fármacos , Vasodilatadores/farmacologíaRESUMEN
How can antiparasite defence traits evolve even if they do not directly benefit their carriers? An example of such an indirect defence is rebellion of enslaved Temnothorax longispinosus ant workers against their social parasite Temnothorax americanus, a slavemaking ant. Ant slaves have been observed to kill their oppressors' offspring, a behaviour from which the sterile slaves cannot profit directly. Parasite brood killing could, however, reduce raiding pressure on related host colonies nearby. We analyse with extensive computer simulations for the Temnothorax slavemaker system under what conditions a hypothetical rebel allele could invade a host population, and in particular, how host-parasite dynamics and population structure influence the rebel allele's success. Exploring a wide range of model parameters, we only found a small number of parameter combinations for which kin selection or multilevel selection could allow a slave rebellion allele to spread in the host population. Furthermore, we did not detect any cases in which the reduction of raiding pressure in the close vicinity of the slavemaker nest would substantially contribute to the inclusive fitness of rebels. This suggests that slave rebellion is not costly and perhaps a side-effect of some other beneficial trait. In some of our simulations, however, even a costly rebellion allele could spread in the population. This was possible when host-parasite interactions led to a metapopulation dynamic with frequent local extinctions and recolonizations of demes by the offspring of few immigrants.
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Altruismo , Hormigas , Interacciones Huésped-Parásitos , Animales , Simulación por Computador , Conducta SocialRESUMEN
The evolution of parasite virulence and host defences is affected by population structure. This effect has been confirmed in studies focusing on large spatial scales, whereas the importance of local structure is not well understood. Slavemaking ants are social parasites that exploit workers of another species to rear their offspring. Enslaved workers of the host species Temnothorax longispinosus have been found to exhibit an effective post-enslavement defence behaviour: enslaved workers were observed killing a large proportion of the parasites' offspring. As enslaved workers do not reproduce, they gain no direct fitness benefit from this 'rebellion' behaviour. However, there may be an indirect benefit: neighbouring host nests that are related to 'rebel' nests can benefit from a reduced raiding pressure, as a result of the reduction in parasite nest size due to the enslaved workers' killing behaviour. We use a simple mathematical model to examine whether the small-scale population structure of the host species could explain the evolution of this potentially altruistic defence trait against slavemaking ants. We find that this is the case if enslaved host workers are related to nearby host nests. In a population genetic study, we confirm that enslaved workers are, indeed, more closely related to host nests within the raiding range of their resident slavemaker nest, than to host nests outside the raiding range. This small-scale population structure seems to be a result of polydomy (e.g. the occupation of several nests in close proximity by a single colony) and could have enabled the evolution of 'rebellion' by kin selection.
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Evolución Biológica , Interacciones Huésped-Parásitos/fisiología , Himenópteros/fisiología , Himenópteros/parasitología , Altruismo , Animales , Femenino , Interacciones Huésped-Parásitos/genética , Himenópteros/genética , Masculino , Modelos Biológicos , Dinámica Poblacional , Conducta SocialRESUMEN
The genetic structure of social insect populations is influenced by their social organization and dispersal modes. The ant Hypoponera opacior shows diverse reproductive behaviours with regular cycles of outbreeding via winged sexuals and inbreeding via within-nest mating wingless sexuals that reproduce by budding. This unusual life cycle should be reflected in the genetic population structure, and we studied this on different scales using microsatellites. On a macrogeographic scale, populations were considerably structured and migration rates within the Chiricahuas were higher than those in between mountain ranges. On a local scale, our analyses revealed population viscosity through dependent colony foundation and a high genetic diversity with a multicolonial structure. The latter was also evident from recognition trials revealing consistent aggression between non-nestmates. Within-nest matings led to high inbreeding coefficients. Finally, the observed seasonal changes in relatedness can be explained by variation in queen number and differential dispersal of the two reproductive morphs.
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Hormigas/genética , Genética de Población , Conducta Sexual Animal/fisiología , Agresión , Alelos , Migración Animal , Animales , Hormigas/fisiología , Femenino , Sitios Genéticos , Variación Genética , Genotipo , Geografía , Endogamia , Estadios del Ciclo de Vida/fisiología , Masculino , Repeticiones de Microsatélite , Reproducción/genética , Reproducción/fisiología , Estaciones del AñoRESUMEN
OBJECTIVES: Ceramide and sphingosine mediate response to cancer therapy, inhibit cell growth and induce apoptosis in vitro. Only a few clinical data about the impact of ceramide and sphingosine iny vivo are available. We investigated the relevance of ceramide- and sphingosine-generating enzymes in breast cancer (acid ceramidase 1 (ASAH1), ceramide synthases 4 (LASS4) and 6 (LASS6)) by means of gene expression analysis. METHODS: We analyzed differences in ASAH1, LASS4 and LASS6 on mRNA level between breast cancer subgroups using microarray data from 1581 tumor samples. RESULTS: High ASAH1, LASS4 and LASS6 expression correlates with pathohistological grading (p < 0.001) and estrogen receptor (ER) status (p < 0.001). High ASAH1 expression was associated with a larger tumor size >2 cm (p = 0.003), while high LASS6 expression was correlated with ErbB2 negativity (p < 0.001). In survival analysis, we detected a significant better prognosis of patients with higher ASAH1 expression (p = 0.002) in the ER-positive subgroup. In contrast, expression of LASS4 or LASS6 did not show any prognostic impact. In the multivariate analysis, only ASAH1 expression (p = 0.002), tumor size (p < 0.0001) and ErbB2 positivity (p = 0.041) remained significant. CONCLUSION: ASAH1 is an estrogen-dependent member of the sphingolipid metabolism, which might provide further prognostic information in ER-positive breast cancers.
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Ceramidasa Ácida/genética , Neoplasias de la Mama/enzimología , Expresión Génica , Receptores de Estrógenos/análisis , Neoplasias de la Mama/química , Neoplasias de la Mama/patología , Femenino , Genes erbB-2/genética , Humanos , Inmunohistoquímica , Persona de Mediana Edad , Análisis de Secuencia por Matrices de Oligonucleótidos , Oxidorreductasas/genética , Pronóstico , Modelos de Riesgos Proporcionales , ARN Mensajero/análisis , Esfingolípidos/metabolismoRESUMEN
Anaplastic large cell lymphoma (ALCL) is a main type of T-cell lymphomas and comprises three distinct entities: systemic anaplastic lymphoma kinase (ALK) positive, systemic ALK(-) and cutaneous ALK(-) ALCL (cALCL). Little is known about their pathogenesis and their cellular origin, and morphological and immunophenotypical overlap exists between ALK(-) ALCL and classical Hodgkin lymphoma (cHL). We conducted gene expression profiling of microdissected lymphoma cells of five ALK(+) and four ALK(-) systemic ALCL, seven cALCL and sixteen cHL, and of eight subsets of normal T and NK cells. The analysis supports a derivation of ALCL from activated T cells, but the lymphoma cells acquired a gene expression pattern hampering an assignment to a CD4(+), CD8(+) or CD30(+) T-cell origin. Indeed, ALCL display a down-modulation of many T-cell characteristic molecules. All ALCL types show significant expression of NFkappaB target genes and upregulation of genes involved in oncogenesis (e.g. EZH2). Surprisingly, few genes are differentially expressed between systemic and cALCL despite their different clinical behaviour, and between ALK(-) ALCL and cHL despite their different cellular origin. ALK(+) ALCL are characterized by expression of genes regulated by pathways constitutively activated by ALK. This study provides multiple novel insights into the molecular biology and pathogenesis of ALCL.
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Perfilación de la Expresión Génica , Regulación Neoplásica de la Expresión Génica , Enfermedad de Hodgkin/genética , Linfoma Anaplásico de Células Grandes/genética , Adolescente , Adulto , Anciano , Quinasa de Linfoma Anaplásico , Línea Celular , Femenino , Enfermedad de Hodgkin/patología , Humanos , Inmunohistoquímica , Células Asesinas Naturales/citología , Células Asesinas Naturales/fisiología , Linfoma Anaplásico de Células Grandes/patología , Masculino , Microdisección , Persona de Mediana Edad , FN-kappa B/metabolismo , Fenotipo , Proteínas Tirosina Quinasas/genética , Proteínas Tirosina Quinasas Receptoras , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Linfocitos T/citología , Linfocitos T/fisiología , Adulto JovenRESUMEN
Survivin functions as an apoptosis inhibitor and a regulator of cell division in many tumours. The intracellular localization of survivin in tumours has been suggested as a prognostic marker. However, current reports are inconsistent and the underlying molecular mechanisms are not understood. The present study has examined the localization and prognostic value of nuclear and cytoplasmic survivin in the pre-therapeutic biopsies from 71 oral and oropharyngeal squamous carcinoma (OSCC) patients. Statistical analysis indicated that preferential nuclear versus cytoplasmic survivin correlated with favourable versus unfavourable disease outcome. Uni- and multi-variate analysis showed that in contrast to total survivin expression, the difference between nuclear and cytoplasmic survivin was a strong predictor for relapse-free survival (p=0.0003). As a potential underlying molecular mechanism, it is shown in OSCC cell lines that predominantly cytoplasmic survivin mediates protection against chemo- and radio-therapy-induced apoptosis. Importantly, the cytoplasmic localization of survivin is regulated by its nuclear export signal (NES), and export-deficient nuclear survivin is not cytoprotective. This study suggests that the difference between cytoplasmic and nuclear survivin is an indicator for survivin activity in tumour cells. Thus, this difference may serve as a predictive marker of outcome in OSCC patients undergoing multi-modality therapy. The pharmacogenetic interference with survivin's cytoplasmic localization is also to be pursued as a potential therapeutic strategy.
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Biomarcadores de Tumor/análisis , Carcinoma de Células Escamosas/química , Inhibidores de Cisteína Proteinasa/análisis , Neoplasias de Cabeza y Cuello/química , Proteínas Asociadas a Microtúbulos/análisis , Proteínas de Neoplasias/análisis , Apoptosis/fisiología , Carcinoma de Células Escamosas/tratamiento farmacológico , Carcinoma de Células Escamosas/radioterapia , Línea Celular Tumoral , Núcleo Celular/química , Citoplasma/química , Neoplasias de Cabeza y Cuello/tratamiento farmacológico , Neoplasias de Cabeza y Cuello/radioterapia , Humanos , Inmunohistoquímica/métodos , Proteínas Inhibidoras de la Apoptosis , Estimación de Kaplan-Meier , Carioferinas/análisis , Neoplasias de la Boca/química , Neoplasias de la Boca/tratamiento farmacológico , Neoplasias de la Boca/radioterapia , Señales de Exportación Nuclear/fisiología , Neoplasias Orofaríngeas/química , Neoplasias Orofaríngeas/tratamiento farmacológico , Neoplasias Orofaríngeas/radioterapia , Pronóstico , Receptores Citoplasmáticos y Nucleares/análisis , Survivin , Proteína Exportina 1RESUMEN
When two sequences are aligned with a single set of alignment parameters, or when mutation parameters are estimated on the basis of a single "optimal" sequence alignment, the variability of both the alignment and the estimated parameters can be seriously underestimated. To obtain a more realistic impression of the actual uncertainty, we propose sampling sequence alignments and mutation parameters simultaneously from their joint posterior distribution given the two original sequences. We illustrate our method with human and orangutan sequences from the hyper variable region I and with gene-pseudogene pairs.
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Alineación de Secuencia/métodos , Animales , Evolución Molecular , Humanos , Funciones de Verosimilitud , Modelos Estadísticos , Pongo pygmaeus , SeudogenesRESUMEN
A permeable reactive barrier (PRB) containing zerovalent iron [Fe(O)] was installed at a former uranium milling site in Monticello, UT. A large-scale column experiment was conducted at the site to test the feasibility of Fe(O) to treat U prior to installing the PRB. Effluents from the field column experiment had pH values near 7.34, moderate decreases in C(IV) and Ca concentrations, and an elevated Fe concentration (27.1 mg/L). In contrast, groundwater exiting the PRB had a pH value of 9.82, decreases in C(IV) and Ca concentrations, and a low concentration of Fe (0.17 mg/L). A geochemical model was used to explain the chemical changes that occurred in both the field column experiment and the PRB. The model simulated the systems by the progressive irreversible dissolution of Fe(O). Modeling results indicated that a longer residence time in the PRB compared with the shorter residence time in the column contributed to the disparate effluent qualities. Prior to modeling, a controlled laboratory column experiment was conducted to help evaluate the dominant chemical mechanisms by which Fe(O) removes U from aqueous solutions. Results of the laboratory column experiment indicated that only a small amount of U could be adsorbed to ferric minerals, and, therefore, this mechanism was not considered in the model.
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Hierro/química , Uranio/química , Calcio/química , Precipitación Química , SolubilidadRESUMEN
BACKGROUND: Treatment of periodontally diseased multi-rooted posterior teeth has conventionally consisted of scaling and root planing, apically positioned flaps, tunneling, root amputation, root resection, guided tissue regeneration, osseous grafting, and combination osseous graft and barrier membrane techniques. Successful treatment has often been directed and measured by how well the clinician obtains sufficient access to facilitate patient hygiene efforts. Long-term success is predicated upon tooth retention and the arrest of further destruction within the furcation area. METHODS: Seventeen adult periodontal patients with Class III furcation defects were evaluated. Using an open flap procedure, a resin-ionomer was placed into all 3 furcation defects. The patients were placed on quarterly maintenance appointments and the teeth evaluated up to 1 year. RESULTS: The results revealed that sealing the furcations of multi-rooted teeth with hopeless prognoses seems to be a viable alternative to accessing the same intraradicular areas for maintenance using more conventional modes of therapy. Sealing further decreases the surface area of the furca and simplifies future maintenance. CONCLUSIONS: The present study showed that teeth with hopeless prognoses might be retained by decreasing probing depths, bleeding upon probing, and mobility when furcation areas are sealed with a resin-ionomer.
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Defectos de Furcación/terapia , Cementos de Resina , Adulto , Anciano , Diente Premolar , Placa Dental/prevención & control , Estudios de Seguimiento , Defectos de Furcación/clasificación , Cementos de Ionómero Vítreo , Humanos , Persona de Mediana Edad , Diente Molar , Higiene Bucal , Pronóstico , Resinas Sintéticas , Propiedades de Superficie , Colgajos Quirúrgicos , Movilidad Dentaria/terapia , Raíz del Diente , Resultado del TratamientoRESUMEN
Myo-inositol (mI) as a precursor in the phosphatidylinositol second messenger system has been reported to be reduced in depression. By means of proton-magnetic resonance spectroscopy (1H-MRS) the mI levels in the frontal brain were investigated in vivo in the present study. Twenty-two patients (mean age: 42.8 +/- 10.7 years) with depressive episodes according to ICD 10 (HAMD score > 17) were compared to 22 healthy subjects (28.0 +/- 5.3 years). Two voxels (30 x 20 x 20 mm3) in the frontal lobes were examined in a Siemens Magnetom SP 4000 at 1.5 T (STEAM sequence: TR = 3500 ms, TE = 55 ms). With the total creatine (Cr) as an internal standard, mI/Cr ratios were calculated to follow the mI levels. In the left frontal lobe, mI/Cr was 0.43 +/- 0.06 in depressive patients and 0.46 +/- 0.07 in healthy subjects; concerning the right frontal lobe, mI/Cr was 0.46 +/- 0.08 and 0.48 +/- 0.06, respectively. There were neither significant differences between the two groups nor between the hemispheres. Since there was a significant positive correlation (R = 0.6) between the age and the mI/Cr in the right frontal lobe of depressed patients, age matched pairs analysis was performed (n = 2 x 10, in each group: nine females, one male, < 40 years). In the right frontal lobe, the patients' mI/Cr of 0.40 +/- 0.05 was now significantly lower than the controls' mI/Cr of 0.45 +/- 0.06. However, most of the patients were on antidepressive medication. Interestingly, it was exactly this group of patients which showed significantly lower mI levels. We regard our investigation as a pilot study which suggests an influence of age and antidepressants on mI levels and should be taken into consideration in further investigations in depressive patients.
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Depresión/metabolismo , Lóbulo Frontal/metabolismo , Inositol/metabolismo , Resonancia Magnética Nuclear Biomolecular , Adulto , Factores de Edad , Análisis de Varianza , Antidepresivos/uso terapéutico , Creatina/metabolismo , Depresión/diagnóstico , Depresión/tratamiento farmacológico , Femenino , Humanos , Masculino , Persona de Mediana Edad , Proyectos Piloto , Escalas de Valoración Psiquiátrica , Reproducibilidad de los Resultados , Factores Sexuales , Estadísticas no ParamétricasRESUMEN
We have performed a multicentre trial to assess the performance of three techniques for absolute quantification of cerebral metabolites using in vivo proton nuclear magnetic resonance (NMR). The techniques included were 1) an internal water standard method, 2) an external standard method based on phantom replacement, and 3) a more sophisticated method incorporating elements of both the internal and external standard approaches, together with compartmental analysis of brain water. Only the internal water standard technique could be readily implemented at all participating sites and gave acceptable precision and interlaboratory reproducibility. This method was insensitive to many of the experimental factors affecting the performance of the alternative techniques, including effects related to loading, standing waves and B1 inhomogeneities; and practical issues of phantom positioning, user expertise and examination duration. However, the internal water standard method assumes a value for the concentration of NMR-visible water within the spectroscopic volume of interest. In general, it is necessary to modify this assumed concentration on the basis of the grey matter, white matter and cerebrospinal fluid (CSF) content of the volume, and the NMR-visible water content of the grey and white matter fractions. Combining data from 11 sites, the concentrations of the principal NMR-visible metabolites in the brains of healthy subjects (age range 20-35 years) determined using the internal water standard method were (mean+/-SD): [NAA]=10.0+/-3.4 mM (n=53), [tCho]=1.9+/-1.0 mM (n=51), [Cr + PCr]=6.5+/-3.7 mM (n=51). Evidence of system instability and other sources of error at some participating sites reinforces the need for rigorous quality assurance in quantitative spectroscopy.
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Encéfalo/metabolismo , Espectroscopía de Resonancia Magnética/métodos , Adulto , Agua Corporal/metabolismo , Calibración , Protocolos Clínicos , Europa (Continente) , Humanos , Espectroscopía de Resonancia Magnética/instrumentación , Fantasmas de Imagen/estadística & datos numéricosRESUMEN
Two high resolution crystal structures of cytosolic aspartate aminotransferase from pig heart provide additional insights into the stereochemical mechanism for ligand-induced conformational changes in this enzyme. Structures of the homodimeric native structure and its complex with the substrate analog 2-methylaspartate have been refined, respectively, with 1.74-A x-ray diffraction data to an R value of 0.170, and with 1.6-A data to an R value of 0.173. In the presence of 2-methylaspartate, one of the subunits (subunit 1) shows a ligand-induced conformational change that involves a large movement of the small domain (residues 12-49 and 327-412) to produce a "closed" conformation. No such transition is observed in the other subunit (subunit 2), because crystal lattice contacts lock it in an "open" conformation like that adopted by subunit 1 in the absence of substrate. By comparing the open and closed forms of cAspAT, we propose a stereochemical mechanism for the open-to-closed transition that involves the electrostatic neutralization of two active site arginine residues by the negative charges of the incoming substrate, a large change in the backbone (phi,psi) conformational angles of two key glycine residues, and the entropy-driven burial of a stretch of hydrophobic residues on the N-terminal helix. The calculated free energy for the burial of this "hydrophobic plug" appears to be sufficient to serve as the driving force for domain closure.
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Aspartato Aminotransferasas/química , Citosol/enzimología , N-Metilaspartato/análogos & derivados , Ácido Acético/farmacología , Animales , Aspartato Aminotransferasas/metabolismo , Sitios de Unión , Cristalografía por Rayos X , Formiatos/farmacología , Sustancias Macromoleculares , Modelos Moleculares , Datos de Secuencia Molecular , N-Metilaspartato/metabolismo , Conformación Proteica/efectos de los fármacos , Estructura Secundaria de Proteína , Estructura Terciaria de Proteína , PorcinosRESUMEN
Aspartate aminotransferase from Escherichia coli, an 88 kDa enzyme, was uniformly and selectively enriched with 15N and was studied by heteronuclear multiple-quantum coherence NMR spectroscopy in H2O. Good resolution was obtained for the downfield region (above 9.5 ppm chemical shift in the 1H dimension) for NH protons in the amide, indole, imidazole, and guanidinium group regions and several resonances were tentatively assigned. Two downfield resonances, at 12.6 and 11.36 ppm, appear to belong to oxygen- or sulfur-bound protons. The most downfield amide resonance at 11.78 ppm was assigned to the active site cysteine 192 whose peptide proton is 2.9 A away from the negatively charged carboxyl group of aspartate 199. Large downfield shifts (up to 1.15 ppm) of the indole NH resonance of the active site tryptophan 140 were observed upon binding of dicarboxylic inhibitors to the pyridoxal 5'-phosphate (PLP) form and of inorganic dianions to the pyridoxamine 5'-phosphate (PMP) form of the enzyme. We discuss these striking differences in the light of the available crystallographic data. Active sites of proteins, as well as specific inhibitory molecules, often contain negatively charged groups. These may be able to form hydrogen-bonds to NH groups and to shift the NH resonances downfield into a less crowded and therefore more readily observable region for many large proteins. Our approach, which makes use of both HMQC spectroscopy and NOE observations, should be widely applicable.
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Aspartato Aminotransferasas/química , Aspartato Aminotransferasas/metabolismo , Sitios de Unión , Escherichia coli , Espectroscopía de Resonancia Magnética , Modelos Moleculares , Peso Molecular , Conformación Proteica , Fosfato de Piridoxal/metabolismo , Piridoxamina/análogos & derivados , Piridoxamina/metabolismoRESUMEN
Excisional biopsies require wide margins to facilitate removal of diseased tissue. Such margins often result in soft-tissue defects. These defects can cause reduced esthetics, ineffective oral hygiene performance, and postsurgical root sensitivity. This case documents the combination of two dental procedures: biopsy and the free gingival graft. A pyogenic granuloma, as diagnosed by histologic report, was removed by excisional biopsy and the resultant defect repaired by using a free gingival graft. Palatal tissue was grafted immediately to the site of the biopsy and sutured in place to cover the loss of attached tissue and papilla. At 6 months, the graft appeared to restore gingival health and maintain both esthetics and function in the surgical biopsy site. The patient was well served by correcting the resultant biopsy defect in a one-step procedure which encouraged healing and an excellent esthetic result.
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Encía/trasplante , Enfermedades de las Encías/cirugía , Gingivoplastia/métodos , Granuloma Piogénico/cirugía , Adulto , Biopsia/efectos adversos , Femenino , Humanos , Embarazo , Complicaciones del Embarazo/cirugíaRESUMEN
The polymerase chain reaction (PCR) has become an indispensable tool in modern biological research. Although the application of PCR is a standard routine, we widely lack a theoretical understanding of the dynamic processes involved, especially with respect to the amplification of nonreproducible and/or unexpected amplification products. For one potential source of uncertainty, the presence of nested primer binding sites within an amplifyable DNA locus, we consider a simple stochastic model for the dynamics of PCR amplification of competing products. For commonly used thermostable DNA polymerases lacking a 5'-3'-exonuclease activity, we predict the relative amplification frequencies of competing PCR products dependent on the primer binding probability, the number of PCR cycles, and the number of initial DNA template molecules. At low primer binding probabilities and low numbers of initial DNA template molecules and PCR cycles, we expect the amplification of two products. At high primer binding probabilities and/or high copy numbers of initial template molecules only one main amplification product is predicted at increasing cycle numbers. Furthermore, by means of computer simulation studies we quantify the stochastic variation for the amplification frequencies of competing products.
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Simulación por Computador , Modelos Teóricos , Reacción en Cadena de la Polimerasa/estadística & datos numéricos , Bacteriófago lambda/genética , Secuencia de Bases , ADN/genética , Cartilla de ADN , ADN Viral/genética , Modelos Genéticos , Técnica del ADN Polimorfo Amplificado Aleatorio/estadística & datos numéricos , Reproducibilidad de los Resultados , Programas Informáticos , Procesos EstocásticosRESUMEN
Consistently successful regenerative therapy for furcation defects using membrane techniques remains a challenge for clinicians. The purpose of this study was to determine if the thickness of tissue used to cover the membrane influences postsurgery recession. Thirty-seven (37) moderate to advanced adult periodontitis patients presenting with at least one mandibular or maxillary molar class 1 or 2 facial furcation involvement participated in the study. Mid-facial presurgery recession was recorded from the cemento-enamel junction to the free gingival margin at a reproducible point. Mid-facial tissue thickness was measured using calipers at a point 5 mm apical to the gingival margin of the mucogingival flap reflected at the time of guided tissue regeneration surgery. Patients were divided into 2 groups based upon tissue thickness measurement. Patients were then re-evaluated for recession at 6 months postsurgery. Sixteen (16) patients with tissue thickness < or = 1 mm demonstrated a mean 2.1 mm increase in recession, while 21 patients with tissue thickness > 1 mm exhibited a mean 0.6 mm increase in recession. We conclude that there is less post-treatment recession (P < 0.01) for tissue thickness > 1 mm than tissue thickness < or = 1 mm. Hence, thickness of gingival tissue covering a membrane appears to be a factor to consider if post-treatment recession is to be minimized or avoided.