人外周血白细胞端粒DNA长度变化与性别的关系

目的 探讨人外周血白细胞端粒DNA长度变化与性别的关系。方法 选取123例不同年龄健康人外周血样本，其中男性63例，女性60例，酚氯仿法抽提人基因组DNA，采用地高辛标记探针，通过Southern Blot方法检测端粒DNA限制性酶切片段(TRF)长度的变化。结果 123例外周血白细胞端粒TRF平均长度随年龄增长而逐渐缩短，TRF随年龄缩短的速度是不均一的，且呈现出性别差异。结论 人外周血白细胞端粒DNA长度随年龄缩短的变化速率具有性别差异，通过端粒DNA长度推断个体年龄需考虑到性别因素。     

端粒DNA在法医学年龄推断中的应用

法医学中年龄推断的常用方法是对齿龄和骨龄进行推断,但这二种方法都受地理环境、营养状况、生活习惯、民族等因素的影响,尤其对成年人而言准确性会下降。随着对端粒研究的不断深入,已证实端粒DNA长度可反映细胞的分裂程度,代表细胞的生长寿命并与供体年龄有负相关性,因此测定端粒DNA长度有望成为法医学推断年龄有价值的新方法。     

线粒体DNA和端粒与年龄相关性的研究进展

用DNA技术从分子水平上推断年龄,已成为法医学和人类学研究领域的新热点。目前用于年龄推断研究的DNA标记主要是线粒体和端粒。本文从线粒体DNA和端粒的概念、线粒体DNA的缺失和突变、端粒长度变化与年龄的相关性等方面对该领域的研究进展进行了综述。旨在为法医实践及进一步的研究提供新的方法和思路。     

创建分子年龄解剖学——对端粒长度检测在法医学中应用价值的探讨

在法医学实践中 ,个体年龄的确定 ,主要是通过对骨骼和牙齿等的检测来进行的 ,而人体组织、碎块则难以推断年龄。近年来 ,随着相关学科技术、理论的发展 ,遗留在现场的人体组织日益显示其巨大的法医学应用价值 ,已从最初的仅仅能提供血型的特征到如今可以进行个体识别、性别确定以及判断一些其他的生物学特征。随着生物组织材料在法医学实际工作中重要价值的不断挖掘 ,人们对它的期望也空前的增高 ,希望它能解决更多的问题 ,比如能否利用生物检材来确定个体的年龄呢 ?可以 ,其关键技术就是对端粒 (ｔｅｌｏｍｅｒｅ)长度进行检测。作者在此…     

创建分子年龄解剖学－－对端粒长度检测在法医学中应用价值的探讨

在法医学实践中,个体年龄的确定,主要是通过对骨骼和牙齿等的检测来进行的,而人体组织、碎块则难以推断年龄.近年来,随着相关学科技术、理论的发展,遗留在现场的人体组织日益显示其巨大的法医学应用价值,已从最初的仅仅能提供血型的特征到如今可以进行个体识别、性别确定以及判断一些其他的生物学特征.随着生物组织材料在法医学实际工作中重要价值的不断挖掘,人们对它的期望也空前的增高,希望它能解决更多的问题,比如能否利用生物检材来确定个体的年龄呢?可以,其关键技术就是对端粒(telomere)长度进行检测 .作者在此对有关端粒检测的研究进展进行综述,主要介绍组织学检材进行年龄评估的方法 .     

Determination of age based on the skeleton

A skeleton is reported that was found 40-100 cm under the surface of the earth; the light, porous bones had partially fallen to pieces. The most remarkable point was the discrepancy between the age of the bone and that of the teeth: based on the bones, the age of the living human being was about 30-40 years; on the basis of the teeth, however, the person was much older. The matter was cleared up with the help of a neck chain that was a precursor to the torques worn by the Celts; thus the skeleton was about 2500 years old. As the teeth were worn down much more through more use in prehistoric times than they are today, the age of the living person is likely to be the bone age, which was about 35 years.     

人外周血白细胞端粒DNA长度与年龄的定量关系

目的探讨人外周血白细胞端粒DNA长度变化规律及其与年龄的关系,为法医学推断年龄提供理论依据。方法抽取西藏那曲地区0~81岁健康人外周血样本105例,其中男性53例,女性52例,采用Southern杂交法检测其端粒限制性片断平均长度。各年龄组性别差异作t检验,端粒长度与年龄的关系作相关及回归分析。结果人外周血白细胞端粒长度随年龄增长逐渐缩短,且存在性别差异;得到推断年龄回归方程:Y=-16.539X+236.287±9.832。结论人外周血白细胞端粒DNA长度与年龄存在明显相关性,为法医学在分子水平上推断个体年龄提供了可能。     

Estimating age at death from immature human skeletons: an overview

Literature on the estimation of age at death of immature human skeletons is critically reviewed. Those estimating age at death for forensic science purposes should consider all available data, but especially rely upon the most appropriate and accurate methods. Estimates should reflect the possible error resulting from the sex differences and population variability known to be associated with the growth process.     

Estimating sex of the human skeleton based on metrics of the sternum

Estimating the sex of skeletal remains is critical in creating the biological profile of an adult individual. Previous research has shown that analyzing the sternum may lead to an accurate estimation of sex based on studies performed on various populations around the globe, such as Indian, European, African, Canadian and North American. The motivation of the current study is to develop classification functions and sectioning points for use in forensic investigations in the United States. The majority of previously published methods are population specific, meaning the data would not prove useful in the United States. For this study, sternal measurements were collected from the William M. Bass Donated Skeletal Collection located at The University of Tennessee, Knoxville following the metric definitions provided by Schwartz and Bass. This collection consists of recent skeletal remains with known age at death, ancestry and sex. Material for the present study consisted of 410 human sterna: 285 male (256 American White/29 American Black) and 125 female (120 American White/5 American Black). Previous studies analyze the applicability of Hyrtl's law in the estimation of sex. This law follows that the mesosternum is greater than twice the length of the manubrium in males and in females the length of the manubrium is greater than half the length of the mesosternum. In this study, comparisons of the proportion of the length of the manubrium to the length of the mesosternum were performed to determine if Hrytl's law is applicable in an American population. Comparisons of these measurements between individuals identified as American Black and American White were analyzed to determine whether this method could be used on both population groups. Further, discriminant function analysis was used to estimate sex and provide a population specific classification function for use in the United States. The discriminate function analysis produced an overall cross-validation classification rate of 84.12% for sex estimation. The cross-validation classification rate for males and females was 80.00% and 88.24%, respectively.     

年龄推断的分子生物学研究进展

法医学中传统的年龄评估主要通过对骨骼、牙齿等组织的形态学检验进行推断,误差甚大,且无法对现场遗留的一些特殊的微量检材进行年龄评估。随着细胞生物学和分子生物学的发展,在细胞和分子水平发现了一些与年龄紧密相关的指标,并提出“分子年龄”这一新概念,为相关学科进行年龄评估提供了新的技术手段。     

Radiographic age estimation based on degenerative changes of vertebrae

Age estimation is an important component of decedent identification. When assessing adult remains, anthropologists frequently use gross examination of skeletal elements, such as clavicles, ribs, and pubic symphyses. For fleshed bodies, this requires the removal of these elements and maceration prior to analysis. A new method was developed using radiographic imaging to estimate age from degenerative changes of the lower thoracic and upper lumbar vertebrae. This technique will complement anthropological age estimation methods in young and middle-aged adults and may serve as a stand-alone method for older individuals. Digital radiographs from 240 medical examiner cases were evaluated. The sample included 120 females and 120 males between the ages of 18 and 101 years. A 3-phased scoring system was used for the target vertebrae. Transition analysis was conducted on binned average scores and a Bayesian approach was used to assign age intervals. At the 90% credible interval, individuals in Bin 1 were under 36 years of age while those in Bin 3 were over 47 years of age. Individuals in Bin 2 showed too much age variation to be informative. No significant differences were found between males and females. These findings will be especially useful in the age estimation of older adults and may eliminate the need for skeletal sampling in medicolegal cases where advanced degenerative changes are radiographically observed in the lower thoracic and/or upper lumbar vertebrae. This method was developed for use on fleshed individuals but may also be applicable to skeletonized remains.     

Approaches to chronological age assessment based on dental calcification

The aim of the present study was to find an accurate estimation of chronological age using a small number of selected teeth. For this purpose, the method devised by Nolla [C. Nolla, The development of the permanent teeth, J. Dent. Child. 27 (1960) 254-266.] was used: the development of each of the teeth was determined according to this method on 374 radiographs, 195 of boys (mean age 8.59) and 179 of girls (mean age 8.75). The 28 variables representing the calcification stages were analyzed using cluster analysis followed by multivariate analysis (multiple linear regression model). Patient age was considered to be a dependent variable. Our study showed that antimere teeth are the most homogeneous as regards stages of development. The prediction was more accurate for boys and girls below 10 years of age, using teeth 21, 43 and 46 from boys and teeth 21, 46 and 47 from girls. These teeth accounted for 80% total variance of chronological age for dental calcification. Standard error was +/-1.4 years for boys and +/-1.2 years for girls. When the age of the children remained completely unknown, the best estimates were provided by teeth 43, 47, 46 and 44 from boys and teeth 44, 47 and 43 from girls.     

Failure of use of cemental annulations in teeth to determine the age of humans

The reliability of cemental annulation counts in teeth was examined to determine its value as an age indicator for humans. One hundred extracted human teeth were embedded in polyester casting resin and sectioned using a diamond wafering saw. Thin sections were photomicrographed, projected, and counted in a double blind random method of presentation. The age of the specimen was determined by adding the number of cemental annulations counted by the observers and the eruption age of the specific tooth that was used. The data analyzed by simple regression indicated that determining chronologic age in humans from cemental annulations is not possible.     

Estimating age in Maori, Pacific Island, and European children from New Zealand

The islands of New Zealand are populated by persons of European, Maori, and Pacific Island extraction. The purpose of this research is to quantify the levels of dental maturation of each of these three populations, in order to obtain data that will be useful in forensic identification and age estimation. The sample consisted of 1383 orthopantomographs (660 males, 723 females) of 477 Maori, 762 European, and 144 Pacific Island children between the ages of 3 and 14 years. Each radiograph was digitized and the stages of mineralization of the seven left mandibular permanent teeth were assessed using the eight stages described by Demirjian. Values for 1, 3, 5, 50, 95, 97, and 99% confidence intervals are listed for each maturity score. Intra-observer reliability was evaluated using Bland-Altman's method on data from re-scoring one out of every 20 radiographs and standard dental maturation curves were constructed for the three populations by means of a quantile regression method. Despite the fact that quantile regression analysis showed that across the age group investigated there were differences between boys and girls, knowledge of the sex does not increase the accuracy of the age estimate, simply because the magnitude of the error of age estimation is greater than the difference between the sexes. Our analysis also shows that population divergence is most marked after the age of 9 years, with a peak difference seen at age 10.     

A comparison of criminal sexual conduct defendants based on victim age

This study compared defendants charged with Criminal Sexual Conduct whose victims were <6 years of age with defendants whose victims were 12 or more years of age. The study included 163 men referred to the evaluation unit of a state center for forensic psychiatry. Thirty-eight men had younger victims (YVs) and 125 men had older victims (OVs). The variables of comparison were defendant demographic and psychiatric variables frequently identified in the sex offender literature. Controlling for other demographic and psychiatric variables by use of logistic regression modeling, elderly defendants (60 years or greater), and incest offenders were three times more likely to have YVs (Odds Ratio [OR] 3.08 and 3.11, respectively). Unlike previous studies defendants with serious psychiatric pathology (psychosis or mania) were no more likely to have YVs (OR 0.66) than were defendants without psychosis.     

Morphometric analysis of the dental pulp chamber as a method of age determination in humans.

Eighty bite-wing radiographs from 40 female and 40 male patients were selected from the patient record system at the University of Texas Dental School at San Antonio, Texas. All samples were equally divided into four age groups, with a range from 15 to 55 years of age. The lower right first permanent molar tooth was chosen as the representative tooth for measuring the maximum height and width of the pulp chamber. The reproducibility of the method was checked by repeating all measurements on two different occasions. Regression analysis indicates that the height and width of the pulp chamber were negatively correlated with age (height r = -0.376 and width r = -0.125). The coefficient of determination (r2) for pulp chamber height and width were 0.123 and 0.058, respectively. This indicates that although there appears to be a definite relationship between the age of an individual and the height and width of the dental pulp chamber, these measures cannot be used as a reliable method of age determination.     

Determination of the human age based on the characteristics of the bone tissue

The principal characteristics of the investigations concerning estimation of the human age are presented. The new high-precision methods for the microosteometric determination of the biological age of man have been developed. The methodological basis for the application of microosteomeric data to the computer-assisted analysis of the images has been created. Taken together, the results of the present study guarantee the high accuracy of the measurements, save labour time, and expand the possibilities for the documentation and control of the experts' work.     

Model of age estimation based on dental factors of unknown cadavers among Iranians

Two hundred and ten cadavers ranging in age from 25 to 60 were studied. Thirty subjects from each five-year interval were selected, and data were collected using the mandibular anterior and premolar teeth after extraction. Sections ranging from 0.5 to 1.0 mm were measured by a stereo microscope with a precision of 0.1 mm. The following factors were determined: attrition, periodontosis, root resorption, secondary dentine apposition, cementum apposition, and translucency of the root. Statistical analysis used the sum of ranks of the dental factors as an independent variable in a linear regression model to estimate the age of the cadaver. Among the different mandibular teeth, the sum of ranks of the first premolar factors had the best correlation coefficient with age. The sum of the dental factors presented a better model than each of the factors alone. The first premolar is recommended as the first step in the estimation of age.     

New forensic approach to age determination in children based on tooth eruption

The present study proposes equations for age determination both in living and dead children, obtained with the help of stepwise ascending multiple linear regression. The equations should be applied, based on the number of erupted teeth and tooth germs, which were detected on radiographs, during clinical examination and in infant skeletal remains. The proposed equations proved to be efficient just like Demirjian's method used as a reference today, and permit age estimation till 20 years of age.