Evaluation of cast methods for estimating age from the os pubis.

Age-related changes of the pubic symphysis have gained wide acceptance among physical anthropologists as one basis for estimating adult skeletal age. However, these methods have not been tested by independent observers on large samples with known ages at death that represent contemporary populations. In this study 202 female and 116 male pairs of pubes collected at autopsy were blindly evaluated for age using the McKern-Stewart or Gilbert-McKern and Suchey-Brooks methods. Performance of the methods was measured by mean absolute deviation of true age from scored interval means and frequencies of true age falling within +/- 1 and +/- 2 standard deviations from the mean. The results suggest that the Suchey-Brooks methods are superior in forensic applications and that the racially specific refinement for males should be used. Age estimates should include +/- 2 standard deviations, and chances of error should be considered, especially when advanced age or debilitation is suspected.     

Comparison of two methods for isolating DNA from human skeletal remains for STR analysis

Abstract: The quality and efficiency of a standard organic DNA isolation method and a silica‐based method using the QIAGEN Blood Maxi Kit were compared to obtain human DNA and short tandem repeats (STRs) profiles from 39 exhumed bone samples for paternity testing. DNA samples were quantified by real‐time PCR, and STR profiles were obtained using the AmpFlSTR^® Identifiler^® PCR amplification kit. Overall, the silica‐based method recovered less DNA ranging from 0 to 147.7 ng/g (average 7.57 ng/g, median = 1.3 ng/g) than did the organic method ranging from 0 to 605 ng/g (average 44.27 ng/g, median = 5.8 ng/g). Complete profiles (16/16 loci tested) were obtained from 37/39 samples (95%) using the organic method and from 9/39 samples (23%) with the silica‐based method. Compared with a standard organic DNA isolation method, our results indicate that the published silica‐based method does not improve neither the quality nor the quantity of DNA for STR profiling.     

Comparison of four skeletal methods for the estimation of age at death on white and black adults

ABSTRACT: When analyzing human adult skeletal remains, it is often difficult to decide whether a single aging method will give a more reliable age estimation than a combination of methods. This study evaluates four macroscopic indicators for age estimation on 218 American White and Black individuals, ranging in age from 25 to 90 years of age, from the Terry collection. Individuals in the sample were selected to have a balanced race, sex, and age distribution. The following aging methods were applied to each skeleton by one experienced observer: the Suchey–Brooks (SB) pubic symphysis method, the Lovejoy auricular surface method, the monoradicular teeth Lamendin (LM) method, and the I?can (IC) method for fourth ribs. The statistical study involved the evaluation of inaccuracy and bias (based on median age) for each age indicator and the combination of methods using Principal component analysis (PCA). Analysis was performed on the entire sample, then by race, then sex, and then age group (25–40 years, 41–60 years, and >60 years). PCA was the most accurate method for both racial groups when all age groups are analyzed together. When the sample was divided into age groups, SB was the most accurate for young adults (25–40 years) and LM was the most accurate for middle adults (41–60 years). After the age of 60, all methods are highly inaccurate, although IC gives the lowest inaccuracy. As regards bias, the study highlights the tendency of all methods to overestimate the age of young individuals and to underestimate in the older age group. No single skeletal indicator of age at death is ever likely to reflect accurately the many factors that accumulate with chronological age. In fact, one must use as many dental and skeletal indicators as possible. However, in order to maximize the potential of each method, in the final evaluation one should consider mainly the method or methods that have a higher accuracy for a particular age range.     

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.     

Evaluation and identification of dismembered human remains.

On occasion, pathologists are confronted with cases involving dismembered human remains. Such cases present unique and interesting problems of postmortem identification. Four cases involving dismembered human remains are presented here and practical suggestions on how identification can be achieved are provided.     

Equations for estimating age at death from the pubic symphysis: a modification of the McKern-Stewart method

Morphological changes of the pubic symphysis provide an important means of estimating age at death in the adult skeleton. Today, the most widely used method of symphysial aging is the three-component system devised by McKern and Stewart for males and modified by Gilbert and McKern for females. Examination of the published data for both sexes reveals that the relationship of total symphysial score with predicted age and observed standard deviations can be expressed by a set of simple linear and polynomial equations. This approach is more statistically efficient since it uses the total data base rather then independently treated data subsets in predicting age from total symphysial score. It has the added advantage of providing a simple method of predicting symphysial age on small computers or programmable calculators.     

Microscopical study on estimation of time since death in skeletal remains

For the purpose of estimating time since death in skeletal remains, postmortem changes in human compact bones were examined by microradiography and electron microscopy. The UV-fluorescence of the peripheral zone of compact bone was also examined by microscopic spectrophotometry. Microradiographic examination revealed no morphological changes in bones left in the open air for long periods, except one of 15 years since death. In bones left in the soil, vacuoles of 5-10 microns diameter, which contained a honeycomb-like structure formed by small vacuoles of 0.5-1 microns diameter, were found in the peripheral zone of the substantia compacta approximately 5 years since death, and in bones of 6 years or more, this change extended to the mid-zone. In bones left in the sea for 4-5 years, vacuoles of 5-10 microns diameter were observed in the outer peripheral zone of the substantia compacta. The relative intensity of UV-fluorescence in bones dwindled with time since death and the correlation coefficient was considerably high.     

Maxillary suture obliteration: a visual method for estimating skeletal age.

The purpose of this study was to develop a method of estimating the age of an individual based on obliteration of the four maxillary (palatal) sutures. A sample of 186 individuals of known age, race, and sex were examined. It was found that males of both races (black and white) exhibit more suture obliteration than females at the same age. During the early adult years, maxillary suture obliteration progresses at nearly the same rate in both sexes; however, the age of old individuals may be greatly overestimated using this method. Although this method cannot be used for exact estimates of individual age, it is valuable in establishing the age range, sorting commingled remains, and estimating skeletal age when only the maxilla is present.     

Simple and highly effective DNA extraction methods from old skeletal remains using silica columns

The recovery of DNA data from old skeletal remains is often difficult due to degraded and very low yield of extracted DNA and the presence of PCR inhibitors. Herein, we compared several silica-based DNA extraction methods from artificially degraded DNA, DNA with PCR inhibitors and DNA from old skeletal remains using quantitative real-time PCR. We present a modified large-scale silica-based extraction combined with complete demineralization, that enables maximum DNA recovery and efficient elimination of PCR inhibitors. This is performed with high concentration of EDTA solution for demineralization of bone powder followed by QIAamp^® spin columns and buffers from the QIAquick^® PCR purification kit. We have successfully used this modified technique to perform STR analysis for 55-year-old skeletal remains. The results of this study will contribute to solve the forensic cases dealing with skeletal remains.     

DNA extraction and sex determination of human skeletal remains

DNA was extracted from human bones remained for 3 to 15 years by using the method developed in our laboratory. A pair of X-Y homologous primer were used to amplify the specific DNA fragments of Amelogenin gene. All the 35 samples yielded correct results. Our method is rapid, sensitive and reliable for the sex determination of skeletal remains.     

The evolution of methods for estimating the time of death from body temperature

A chronological survey is offered of the development of concepts and techniques to use body temperature in the estimation of time since death. For a century and a half, this method has been investigated, though accuracy still cannot be claimed, especially in operational conditions.     

Estimation of age at death based on quantitation of the 4977-bp deletion of human mitochondrial DNA in skeletal muscle

The 4977-bp deletion in human mitochondrial DNA (mtDNA) is known to accumulate in various tissues with age. Since this deletion in mtDNA correlates closest with age in muscle tissue, iliopsoas muscle tissue was taken at autopsy from 50 persons aged 24-97 years to determine whether age at death can be estimated based on the amount of the 4977-bp deletion in skeletal muscle. Total DNA (nuclear and mtDNA) was extracted from 100 mg tissue and the 4977-bp deletion quantified using a kinetic polymerase chain reaction (PCR) followed by visualization of the products on silver stained polyacrylamide gels. The amount of the 4977-bp deletion of mtDNA ranged from 0.00049% to 0.14% depending on age, with a correlation coefficient of r = 0.83 (P = 0.0001). In forensic practice this method can aid in the estimation of age at death with a relatively wide confidence interval, thus enabling a discrimination between young and elderly persons in the identification of human remains based solely on skeletal muscle.     

Accuracy of developing tooth length as an estimate of age in human skeletal remains: the deciduous dentition

Dental age assessments are widely used to estimate age of immature skeletal remains. Most methods have relied on fractional stages of tooth emergence and formation, particularly of the permanent dentition, for predicting the age of infants and very young children. In this study, the accuracy of regression equations of developing deciduous tooth length for age estimation (Liversidge et al.) is tested on a sample of 30 Portuguese subadult skeletons of known age at death. Overall the method shows high accuracy and the average difference between estimated and chronological age is between 0.20 and -0.14 years when using single teeth, and 0.06 years, when using all available teeth. However, there is a tendency for the deciduous molars to provide overestimates of chronological age. Results show that age estimates can be obtained within +/-0.10 years with a 95% confidence interval when several teeth are used. Overall between-tooth agreement in age estimates decreases with increasing age but there is less variability of estimates with more teeth contributing to overall mean age. One seemingly limitation of this method may be the fact that it was developed by combining the maxillary and mandibular teeth. The other is related to the accuracy with which radiographic tooth length can be used as a valid surrogate for actual tooth length. Nevertheless, the advantages of this metric method surpass the limitations of chronologies based on stages of dental development.     

Stress deformations of skeletal remains from prehistoric cremation burials

Vertebrae and parts of joints from long bones from prehistoric cremations of the Late Bronze Age and Early Iron Age are presented, showing marked deformations caused by pressure during cremation when bones exposed to temperatures of 400 degrees-500 degrees Centigrade display minimal hardness. The vertebrae with deformation of the arcus parts are only from the lower vertebral column; on account of the weight of this body region, this suggests that the corpse lay in the dorsal position at the place of cremation. The fact that there were deformed arches only on one side might suggest an irregular structure of the surface on which the corpse lay. In the prone position, i.e. in the absence of pressure caused by body weight, all vertebrae should be unaltered; alternatively, if cremation wood was piled on top of the corpse, the arches of thoracic and cervical vertebrae are also likely to be deformed. Deformations resulting from weight bearing were found in the joints of extremities only, with flattening of the heads of joints as well as fissures in the external layers of bones and compression into folds. Some bones show distinct even grooves caused by direct pressure, possibly resulting from the fixation of joint regions for cremation? Evidently the deformations caused by the weighting down of different skeletal regions provide hints that may help in the recognition of cremation rites. It would be helpful if experimental cremations could be performed to establish the pressure necessary to cause deformations.     

Analysis of pathological and non-pathological human skeletal remains by FT-IR spectroscopy

In this study, we report the chemical analyses of various non-pathological, tuberculosis and syphilis infected bone samples from different burial environments by Fourier transform infrared spectroscopy (FT-IR), in the framework of a general study of diagenesis. Dating human skeletal remains is one of the most important and yet unreliable aspects of forensic anthropology. In this paper, a new method has been suggested, using the crystallinity index and carbonate-phosphate index as a means of distinction between recent and archaeological, anthropological bone samples. Pathological bone samples were analyzed with the same method to see if changes in crystallinity interfere with the process of dating.     

A test of the effectiveness of the revised maxillary suture obliteration method in estimating adult age at death

The effectiveness of the original maxillary suture method for estimating age at death, introduced in 1987 by Mann and colleagues, has been tested, but their revised maxillary suture method (1991) has not been subject to similar scrutiny. The purpose of this study is to test the accuracy of the revised maxillary suture method in estimating age at death on a genetically diverse skeletal sample of 155 maxillae (96 males, 59 females, aged 26 to 100 years) of known age at death from the Department of Anatomy and Cell Biology, University of Cape Town, South Africa. Results from a prior study of the original maxillary suture method will be compared. With age category correctly estimated for 83% of this sample, the results of this study indicate that the revised method is more effective in estimating age at death than the original method. The revised method appears to perform best for older individuals and tends to underestimate age for individuals of all age groups. The results suggest that the revised method is useful as a method for age estimation when it is used conjunction with other estimators.     

Processing of skeletal remains. A medical examiner's perspective

A multidisciplinary approach to the investigation of skeletal remains is presented. Guidelines for recovery, documentation, examination, processing, storage, and release of skeletal material are offered and discussed.