RESUMEN
BACKGROUND: The neonatal line (NL) is an important issue in forensic odontology. It is the sign of a developmental birth defect, which is caused by the effect of metabolic stress on tooth structures when the fetus passes to extrauterine life. AIMS: The aim of this research is to determine the existence and thickness of NL in teeth, as it is a legal necessity to indicate the signs of viability at birth in a forensic examination of a fetus or infant case. STUDY DESIGN AND SUBJECTS: This research was conducted on 48 lower left and right lateral teeth, which were taken from 24 autopsy cases (46% female and 54% male). Left lateral teeth were sectioned in a vertical plane and right lateral teeth were sectioned in a horizontal plane. The NL thickness was measured with a scanning electron microscope (SEM). These cases comprised three conditions as: 70.3% normal birth, 16.7% caesarean sections, and 12.5% still birth cases under the legal and ethical permission. OUTCOME MEASURES: The mean NL thickness of normal birth cases was higher than caesarean cases as 7.7µm and 2.5µm, respectively. RESULTS AND CONCLUSIONS: The results showed a statistical significance between all birth conditions. NL does not exist in still birth cases (p<0.001). Not only is the presence of NL a sign of live birth, but also its thickness is an indicator of the delivery mode where NL thickness of normal birth was found thicker than the caesarean cases.
Asunto(s)
Parto Obstétrico/métodos , Esmalte Dental/embriología , Diente Primario/anatomía & histología , Diente Primario/embriología , Cesárea , Esmalte Dental/anatomía & histología , Femenino , Humanos , Recién Nacido , Masculino , Microscopía Electrónica de Rastreo , Embarazo , Mortinato , Diente Primario/ultraestructuraRESUMEN
Forensic identification comprises legal, social, ethical, and religious aspects where age detection is an important factor. When the case is a fetus or infant, recording various measurements of the body, head, and teeth is essential. The aim of this research is to evaluate the effects of different tooth and body measurements and their implications on the age estimation of fetuses and infants. This research was performed on 96 fetus and infant incisor teeth taken from 24 autopsy cases (54 % males and 46 % females) where age of the subjects were within the range of prenatal 16 weeks to postnatal 72 weeks. The data were statistically processed by regression analysis via curve estimations. According to the results, growing patterns of the head circumference (HC) and the upper central tooth measurements indicate a strong relationship, where there is no significant difference for both sexes. The growth patterns of all variables showed a linear function to a certain age (approximately 56 weeks pre-plus postnatal); the tooth height (TH) slightly increases until the closure of the root apex, and the HC gradually stabilizes in time, therefore a log-linear relation was found considerable. The results revealed eight age estimation formulas, including the combination of HC with the labiolingual, mesiodistal (MD), crown height, and TH measurements. Among these, only MD can be applied to a living. In conclusion, tooth and head measurements are found to be the main factors of age estimation formulas.
Asunto(s)
Determinación de la Edad por el Esqueleto/métodos , Determinación de la Edad por los Dientes/métodos , Incisivo/embriología , Cráneo/embriología , Cefalometría , Femenino , Desarrollo Fetal , Antropología Forense , Odontología Forense , Humanos , Masculino , Proyectos Piloto , Análisis de RegresiónRESUMEN
The relevance of innate immune responses to Plasmodium falciparum infection, in particular the central role of natural killer (NK) cell-derived interferon gamma (IFN-γ), is becoming increasingly recognised. Recently, it has been shown that IFN-γ production in response to P. falciparum antigens is in part regulated by killer-cell immunoglobulin-like receptor (KIR) genes, and a study from malaria-exposed Melanesians suggested an association between KIR genotypes and susceptibility to infection. This prompted us to determine and compare the frequencies of 15 KIR genes in Gambian children presenting with either severe malaria (n = 133) or uncomplicated malaria (n = 188) and in cord-blood population control samples (n = 314) collected from the same area. While no significant differences were observed between severe and uncomplicated cases, proportions of individuals with KIR2DS2+C1 and KIR2DL2+C1 were significantly higher among malaria cases overall than in population control samples. In an exploratory analysis, activating KIR genes KIR2DS2, KIR3DS1 and KIR2DS5 were slightly higher in children in disease subgroups associated with the highest mortality. In addition, our data suggest that homozygosity for KIR genotype A might be associated with different malaria outcomes including protection from infection and higher blood parasitaemia levels in those that do get infected. These findings are consistent with a probable role of KIR genes in determining susceptibility to malaria, and further studies are warranted in different populations.
Asunto(s)
Inmunidad Innata , Interferón gamma/inmunología , Células Asesinas Naturales/metabolismo , Malaria Falciparum/inmunología , Plasmodium falciparum/inmunología , Isoformas de Proteínas/inmunología , Receptores KIR/inmunología , Estudios de Casos y Controles , Niño , Preescolar , Femenino , Sangre Fetal/química , Sangre Fetal/inmunología , Gambia , Frecuencia de los Genes , Predisposición Genética a la Enfermedad , Genotipo , Humanos , Lactante , Recién Nacido , Interferón gamma/biosíntesis , Células Asesinas Naturales/inmunología , Malaria Falciparum/mortalidad , Malaria Falciparum/parasitología , Masculino , Isoformas de Proteínas/genética , Receptores KIR/genética , Índice de Severidad de la Enfermedad , Tasa de SupervivenciaRESUMEN
Factor V Leiden (FVL) is the most common monogenic disorder that causes activated protein C (APC) resistance, creating hyper-coagulation. The mutation shows an uneven geographic distribution, significantly high in European populations. The mutation is believed to have originated approximately 20 000 years ago probably from a geographic region close to Anatolia. This fact makes it noteworthy to search for the mutation in ancient populations that once lived in this area. One of these civilizations, Urartu was centered around Van Lake in Eastern Turkey. The archeological remains from the excavations of the region are dated back to 1000 BC. Teeth, taken from the excavations of Van Yoncatepe fortress, were taken into DNA analysis considering all the precautions for ancient DNA analysis. Multiplex STR (Short Tandem Repeats) analysis were performed both to determine the gender of the samples and to conclude that the samples are preserved from modern DNA contamination. After getting an 80% amplification success for amelogenin, a melting curve analysis using lightcycler was performed to determine the FVL genotype of each sample. Of the 60 samples, 1 gave a positive amplification result for FV gene and was found to be heterozygous. To date, the age of this mutation was estimated based on statistical calculations using haplotype frequencies; here for the first time, we report FVL in an ancient population of 3000 years.
Asunto(s)
ADN/genética , Factor V/genética , Fósiles , Diente/química , Resistencia a la Proteína C Activada/genética , Arqueología , ADN/química , Factor V/metabolismo , Pruebas Genéticas , Humanos , Mutación Puntual , TurquíaRESUMEN
Age at time of death for a fetus or infant is an important issue in the field of forensic science. Dental development can give an accurate measure of infant and fetal age and current literature does not include any studies of dental age from central incisor development. The objective of this study is to determine the age of deceased fetuses and infants by examining metric tooth development of central incisors in deceased fetuses and infants. Five dimensions of 76 maxillary and mandibular central incisors were measured: mesio-distal (MD), bucco-lingual (BL), crown height (CH), crown thickness (CT), and root height (RH). The results showed that 44.45+/-0-2 weeks is a sectional time for age calculations, which corresponds to 40 weeks from conception plus 4 to 5 weeks after birth. Four ATA entitled age formulas are derived to give the relation of age with tooth dimensions before and after 44.45 weeks [ATA is the special name given to the honor of the great Turkish leader Mustafa Kemal Atatürk (1881-1938)]. Age estimation can be calculated from these formulas with an accuracy of the age +/-0-2 weeks. Also, calcification time can be determined from ATA formulas. In conclusion, the age of fetuses and infants can be assessed by the measurements of a single central incisor. According to this research, when estimating age during identification studies, forensic researchers must take into consideration the period of embryonic human growth and development.
Asunto(s)
Determinación de la Edad por los Dientes/métodos , Incisivo/anatomía & histología , Diente Primario/anatomía & histología , Análisis de Varianza , Femenino , Feto , Odontología Forense , Humanos , Lactante , Recién Nacido , Modelos Lineales , Masculino , Raíz del Diente/anatomía & histologíaRESUMEN
Styrene is suspected to cause lympho-hematopoietic malignancies through the formation of styrene 7,8-oxide. However, we are still unable to calculate the cancer risk for workers exposed to styrene using epidemiological data. The aims of this study were to determine the blood dose after styrene exposure and to compare the genotoxic potency of styrene 7,8-oxide and gamma radiation in order to calculate the cancer risk by means of the rad-equivalence approach. Leucocytes of 20 individuals were exposed to 0, 0.1, 0.2 or 0.3 mM styrene 7,8-oxide (1 h) or 1, 2 or 3 gray (=100, 200, 300 rad) gamma radiation. Genotoxicity was evaluated with the cytokinesis-block micronucleus assay. Comparison of the two slopes of the regression lines between micronuclei and dose revealed a genotoxic potency for styrene 7,8-oxide of 37 rad/mMh, corresponding with a median value derived from mutagenicity studies (1, 37, 208 rad/mMh). At exposure levels of 1 ppm styrene, a blood styrene 7,8-oxide concentration between 0.03 x 10(-)(6) and 0.42 x 10(-)(6) mM is to be expected using data of toxicokinetic models and human exposure studies. With the cancer risk per unit dose of gamma radiation as benchmark, we calculated a lifetime risk of acquiring a fatal lympho-hematopoietic cancer of 0.17 in 10(3) workers (between 0.037 x 10(-)(3) and 5.0 x 10(-)(3)) exposed to 20 ppm styrene during 40 years.
Asunto(s)
Compuestos Epoxi/toxicidad , Rayos gamma/efectos adversos , Neoplasias Hematológicas/inducido químicamente , Neoplasias Inducidas por Radiación , Adolescente , Adulto , Análisis de Varianza , Animales , Células CHO , Cricetinae , Cricetulus , Relación Dosis-Respuesta a Droga , Relación Dosis-Respuesta en la Radiación , Compuestos Epoxi/sangre , Femenino , Humanos , Masculino , Pruebas de Micronúcleos , Modelos Biológicos , Análisis de Regresión , Medición de RiesgoRESUMEN
The objective of this state of the art paper is to review the mechanisms of induction, the fate, the methodology, the sensitivity/specificity and predictivity of two major cytogenetic endpoints applied for genotoxicity studies and biomonitoring purposes: chromosome aberrations and micronuclei. Chromosomal aberrations (CAs) are changes in normal chromosome structure or number that can occur spontaneously or as a result of chemical/radiation treatment. Structural CAs in peripheral blood lymphocytes (PBLs), as assessed by the chromosome aberration (CA) assay, have been used for over 30 years in occupational and environmental settings as a biomarker of early effects of genotoxic carcinogens. A high frequency of structural CAs in lymphocytes (reporter tissue) is predictive of increased cancer risk, irrespective of the cause of the initial CA increase. Micronuclei (MN) are small, extranuclear bodies that arise in dividing cells from acentric chromosome/chromatid fragments or whole chromosomes/chromatids that lag behind in anaphase and are not included in the daughter nuclei in telophase. The cytokinesis-block micronucleus (CBMN) assay is the most extensively used method for measuring MN in human lymphocytes, and can be considered as a "cytome" assay covering cell proliferation, cell death and chromosomal changes. The key advantages of the CBMN assay lie in its ability to detect both clastogenic and aneugenic events and to identify cells which divided once in culture. Evaluation of the mechanistic origin of individual MN by centromere and kinetochore identification contributes to the high sensitivity of the method. A number of findings support the hypothesis of a predictive association between the frequency of MN in cytokinesis-blocked lymphocytes and cancer development. Recent advances in fluorescence in situ hybridization (FISH) and microarray technologies are modifying the nature of cytogenetics, allowing chromosome and gene identification on metaphase as well as in interphase. Automated scoring by flow cytometry and/or image analysis will enhance their applicability.
Asunto(s)
Aberraciones Cromosómicas/estadística & datos numéricos , Monitoreo del Ambiente/normas , División Celular , Monitoreo Epidemiológico , Humanos , Neoplasias/epidemiología , Neoplasias/prevención & control , Fumar/efectos adversosRESUMEN
STATEMENT OF PROBLEM: Surface treatment methods used for resin bonding to conventional silica-based dental ceramics are not reliable for zirconium-oxide ceramics. PURPOSE: The aim of this study was to compare the effects of airborne-particle abrasion, silanization, tribochemical silica coating, and a combination of bonding/silane coupling agent surface treatment methods on the bond strength of zirconium-oxide ceramic to a resin luting agent. MATERIAL AND METHODS: Sixty square-shaped (5 x 5 x 1.5 mm) zirconium-oxide ceramic (Cercon) specimens and composite resin (Z-250) cylinders (3 x 3 mm) were prepared. The ceramic surfaces were airborne-particle abraded with 125-microm aluminum-oxide (Al(2)O(3)) particles and then divided into 6 groups (n = 10) that were subsequently treated as follows: Group C, no treatment (control); Group SIL, silanized with a silane coupling agent (Clearfil Porcelain Bond Activator); Group BSIL, application of the adhesive 10-methacryloyloxydecyl dihydrogen phosphate monomer (MDP)-containing bonding/silane coupling agent mixture (Clearfil Liner Bond 2V/ Porcelain Bond Activator); Group SC, silica coating using 30-microm Al(2)O(3) particles modified by silica (CoJet System); Group SCSIL, silica coating and silanization (CoJet System); and Group SCBSIL, silica coating and application of an MDP-containing bonding/silane coupling agent mixture (Clearfil Liner Bond 2V/Porcelain Bond Activator). The composite resin cylinders were bonded to the treated ceramic surfaces using an adhesive phosphate monomer-containing resin luting agent (Panavia F). After the specimens were stored in distilled water at 37 degrees C for 24 hours, their shear bonding strength was tested using a universal testing machine at a crosshead speed of 0.5 mm/min. Debonded specimen surfaces were examined with a stereomicroscope to assess the mode of failure, and the treated surfaces were observed by scanning electron microscopy. Bond strength data were analyzed using 1-way analysis of variance and the Duncan test (alpha = .05). RESULTS: The bond strengths (mean +/- SD; MPa) in the groups were as follows: Group C, 15.7 +/- 2.9; Group SIL, 16.5 +/- 3.4; Group BSIL, 18.8 +/- 2.8; Group SC, 21.6 +/- 3.6; Group SCSIL, 21.9 +/- 3.9; and Group SCBSIL, 22.9 +/- 3.1. The bond strength was significantly higher in Group SCBSIL than in Groups C, SIL, and BSIL (P<.001), but did not differ significantly from those in Groups SC and SCSIL. Failure modes were primarily adhesive at the interface between zirconium and the resin luting agent in Groups C and SIL, and primarily mixed and cohesive in Groups SC, SCSIL, and SCBSIL. CONCLUSION: Tribochemical silica coating (CoJet System) and the application of an MDP-containing bonding/silane coupling agent mixture increased the shear bond strength between zirconium-oxide ceramic and resin luting agent (Panavia F).
Asunto(s)
Cerámica/química , Recubrimiento Dental Adhesivo , Materiales Dentales/química , Cementos de Resina/química , Circonio/química , Abrasión Dental por Aire/métodos , Óxido de Aluminio/química , Resinas Compuestas/química , Humanos , Ensayo de Materiales , Metacrilatos/química , Microscopía Electrónica de Rastreo , Resistencia al Corte , Silanos/química , Dióxido de Silicio/química , Estrés Mecánico , Propiedades de Superficie , Temperatura , Factores de Tiempo , Agua/químicaRESUMEN
99mTc-MIBI is currently used, for cardiac investigations, for parathyroid thyroid imaging and evaluation of various tumours. It has been demonstrated that 99mTc-MIBI is specifically taken up by the human peripheral blood lymphocytes (HPBL), cells which are known to be highly radiosensitive. To evaluate the possible chromosomal damage induced on HPBL by their in vitro exposure to increasing activities of 99mTc-MIBI and also to establish whether HPBL undergo apoptosis or necrosis after in vitro exposure to 99mTc-MIBI. Blood from two healthy donors were irradiated, incubated in vitro with increasing activities of 99mTc-MIBI corresponding to absorbed doses ranging from 1 microGy, 100 microGy, 1 cGy, 10 cGy, 50 cGy to 1 Gy. The cytokinesis block micronucleus (MN) assay was used and the frequency of binucleated cells (BN) with MN (MNBN) was analyzed in cultured HPBL (in either the G0- or G1- and S1-phase of the cell cycle). The fluorescence in situ hybridization (FISH) with pancentromeric probes was also applied to study the MN regarding whole chromosomes or acentric fragments. Apoptosis induction by 0.1 Gy of 99mTc-MIBI in HPBL was quantified using annexin-V test. The frequencies of MNBC were similar in control cultures and in HBPL cultures exposed to 1 microGy, 100 microGy and 1 cGy. However, they were significantly higher (P<0.05 versus controls and lower doses) after one treatment exposure to 0.25 mCi of 99mTc-MIBI (corresponding to 10 cGy) or more but the percentages of MNBN with 10 cGy, 50 cGy and 1 Gy did not differ significantly. The increase of MNBN was more pronounced (P<0.05) for cells irradiated during G1 phase than for those irradiated during G0 or S1. Using FISH, 80-90% of the MN were centromere negative. Although small, the absolute number of MN positive for centromeric signal and presumably containing whole chromosomes increased with doses. There is a statistically significant (P=0.001 and 0.006) increase of both apoptotic cells and necrosis, respectively, as compared to control cells in two times studied (24 and 36 h). Chromosomic damages can thus be demonstrated in HPBL after in vitro exposure of blood to at least 0.25 mCi of 99mTc-MIBI corresponding to one absorbed dose of 10 cGy, and for this dose, apoptosis and necrosis phenomenons were detected.
Asunto(s)
Aberraciones Cromosómicas , Linfocitos/efectos de la radiación , Radiofármacos/toxicidad , Tecnecio Tc 99m Sestamibi/toxicidad , Adulto , Apoptosis/efectos de la radiación , Células Cultivadas , Femenino , Humanos , Hibridación Fluorescente in Situ , Linfocitos/ultraestructura , Masculino , Pruebas de MicronúcleosRESUMEN
STATEMENT OF PROBLEM: Available information on the dimensions of the enamel and pulp tissues of tooth structure, as well as their correlation with chronologic age, is limited. However, this information is a significant determinate in planning the tooth reduction for a porcelain laminate veneer (PLV) restoration. PURPOSE: This study examined variations in tooth enamel thickness and its correlation with chronologic age as it relates to available tooth substrate for PLV restorations. MATERIAL AND METHODS: Forty human maxillary central incisors extracted from patients within the age range of 30 to 69 years were used to evaluate the thickness of tooth layers. Measurements were made for the following tooth areas using scanning electron microscopy (SEM): facial enamel thickness at 1, 3, and 5 mm above the cemento-enamel junction (CEJ), palatal enamel thickness at 5 mm above the CEJ, facial and palatal enamel thickness at the incisal edge, maximum facial-palatal (MFP) width at incisal edge, physiologic secondary dentin (PSD) height, facial-cervical enamel-pulp (FCEP) distance, and the incisal edge enamel-pulp (IEP) distance. The relationship between thickness and age was evaluated with a regression analysis (alpha=.05). RESULTS: Significant differences (P<.001) were observed in all of the relationships between tooth thicknesses and chronological age. Outcome variables of enamel thickness related to age showed a steady decrease, beginning at approximately age 50. Mean values of facial enamel thickness at 1, 3, and 5 mm above the CEJ were 0.31 +/- 0.01, 0.54 +/- 0.01, and 0.75 +/- 0.02 mm, respectively, for the age range of 30 to 69 years. The thickness of maximum incisal width (R(2) = 0.95), PSD height (R(2) = 0.76), and IEP distance (R(2) = 0.99) indicated that all are subject to an increase in relation to age. CONCLUSION: Facial enamel thickness above the CEJ decreases, while MFP increases in relation to age. The PSD height and IEP distance also increased with age.
Asunto(s)
Envejecimiento/patología , Esmalte Dental/ultraestructura , Porcelana Dental , Coronas con Frente Estético , Adulto , Anciano , Pulpa Dental/ultraestructura , Dentina Secundaria/ultraestructura , Humanos , Incisivo , Microscopía Electrónica de Rastreo , Persona de Mediana Edad , Odontometría , Cuello del Diente/ultraestructura , Corona del Diente/ultraestructuraRESUMEN
Identification of genetic polymorphisms responsible for reduced DNA repair capacity may allow better cancer prevention. We examined whether variations in genes involved in base-excision (hOGG1, XRCC1) and double strand break (XRCC3) DNA repair contribute to inter-individual differences in genotoxic effects induced in the lymphocytes of 21 cobalt (Co) exposed, 26 hard metal (WC-Co) exposed and 26 matched control male workers. Genotyping was performed by PCR-RFLP. DNA single strand breaks and alkali-labile sites were measured by the alkaline Comet assay. Chromosomal rearrangements resulting from chromosome loss or acentric fragments were assessed as micronucleated mononucleates (MNMC) and binucleates (MNCB) with the cytokinesis-block micronucleus test. Urinary 8-hydroxydeoxyguanosine (8-OHdG) levels were used as an indicator of systemic oxidative DNA damage. A significantly higher frequency of MNMC was observed in WC-Co exposed workers with variant hOGG1(326) genotype. Multivariate analysis performed with genotypes, age, exposure status, type of plant, smoking and their interaction terms as independent variables indicated that MNMC and Comet tail DNA (TD) were influenced by genetic polymorphisms. In the exposed and total populations, workers variant for both XRCC3 and hOGG1 had elevated MNMC frequencies. Further studies will demonstrate whether genotyping for hOGG1 and XRCC3 polymorphisms is useful for a better individual monitoring of workers.
Asunto(s)
Cobalto/toxicidad , ADN Glicosilasas/genética , Proteínas de Unión al ADN/genética , Desoxiguanosina/análogos & derivados , Metales/toxicidad , Exposición Profesional/efectos adversos , 8-Hidroxi-2'-Desoxicoguanosina , Biomarcadores/análisis , Ensayo Cometa , Daño del ADN , Desoxiguanosina/orina , Polvo , Genotipo , Humanos , Masculino , Micronúcleos con Defecto Cromosómico/inducido químicamente , Pruebas de Micronúcleos , Pruebas de Mutagenicidad , Reacción en Cadena de la Polimerasa , Polimorfismo Genético , Polimorfismo de Longitud del Fragmento de Restricción , Proteína 1 de Reparación por Escisión del Grupo de Complementación Cruzada de las Lesiones por Rayos XAsunto(s)
Automedicación , Adolescente , Niño , Preescolar , Estudios Transversales , Escolaridad , Femenino , Humanos , Lactante , Recién Nacido , Madres , Nigeria/epidemiología , Aceptación de la Atención de Salud , Encuestas y CuestionariosRESUMEN
Percutaneous transluminal balloon angioplasty (PTA) was performed in 17 tibial arteries with an average cross-sectional area stenosis of 92% (range 75-99%) in 13 patients (14 limbs) for limb salvage. In 4 of 14 lower extremities, PTA of femoropopliteal arteries was also performed. Technical success with 50% or less residual stenosis was achieved in all 17 tibial vessels. At approximately 2 months after PTA, clinical improvement had occurred in 10 of 14 limbs; no patient was made worse. Most recent follow-up (mean 19 months, range 8-34 months) revealed continued satisfactory clinical success with no further vascular intervention in 9 of these 10 limbs (one patient died). Short segmental stenoses, residual stenoses less than 40% following PTA, and absence of diabetes or gangrene appear to be predictors of favorable clinical outcomes. Our results suggest that PTA of focal tibial stenosis is an effective and safe treatment modality in properly selected patients and that wider use of PTA may be justified.