Luis Ríos

Leishmaniasis presenting as a dermatomyositis-like eruption in AIDS.

Three patients are described with leishmaniasis and AIDS, with cutaneous lesions mimicking dermatomyositis. Leishmania organisms were observed in great numbers in the dermis of lesional skin biopsy specimens. They were also present inside keratinocytes in all layers of the epidermis in one patient. Skin cultures from all patients and bone marrow culture in patients 1 and 3 revealed Leishmania infantum. Leishmania organisms were also found in nonlesional skin. The absence of proximal symmetric muscle weakness, elevated muscle enzymes, myopathic electromyograms, or characteristic histopathologic and immunologic features of dermatomyositis, and the rapid and complete clearance or marked improvement of the cutaneous lesions after treatment for leishmaniasis, make us consider true dermatomyositis unlikely. We suggest that leishmaniasis be included in the list of diseases capable of inducing a dermatomyositis-like eruption.

Sacral fusion as an aid in age estimation

The degree of fusion at the anterior aspect of the sacral vertebrae has been scored in 242 male and female skeletons from the Lisbon documented collection, ranging from 16 to 59 years old in age. Statistical tests indicate a sex difference towards earlier fusion in young females compared with young males, as well as a clear association between degree of fusion and age. Similar results have been found by other authors in documented skeletal samples from Coimbra and Sassari, and the recommendations stated by these authors regarding age estimation have been positively tested in the Lisbon collection. Although more research from geographically diverse samples is required, a general picture of the pattern of sacral fusion and its associations with age and sex is emerging. We also provide a practical example of the usefulness of the sacrum for age estimation in a forensic setting, a mass grave from the Spanish Civil War. It is concluded that the scoring of the degree of fusion of the sacral vertebrae, specially of S(1-2), can be a simple tool for assigning skeletons to broad age groups, and it should be implemented as another resource for age estimation in the study of human skeletal remains.

Differential Growth and Development of the Upper and Lower Human Thorax

The difficulties in quantifying the 3D form and spatial relationships of the skeletal components of the ribcage present a barrier to studies of the growth of the thoracic skeleton. Thus, most studies to date have relied on traditional measurements such as distances and indices from single or few ribs. It is currently known that adult-like thoracic shape is achieved early, by the end of the second postnatal year, with the circular cross-section of the newborn thorax transforming into the ovoid shape of adults; and that the ribs become inclined such that their anterior borders come to lie inferior to their posterior. Here we present a study that revisits growth changes using geometric morphometrics applied to extensive landmark data taken from the ribcage. We digitized 402 (semi) landmarks on 3D reconstructions to assess growth changes in 27 computed tomography-scanned modern humans representing newborns to adults of both sexes. Our analyses show a curved ontogenetic trajectory, resulting from different ontogenetic growth allometries of upper and lower thoracic units. Adult thoracic morphology is achieved later than predicted, by diverse modifications in different anatomical regions during different ontogenetic stages. Besides a marked increase in antero-posterior dimensions, there is an increase in medio-lateral dimensions of the upper thorax, relative to the lower thorax. This transforms the pyramidal infant thorax into the barrel-shaped one of adults. Rib descent is produced by complex changes in 3D curvature. Developmental differences between upper and lower thoracic regions relate to differential timings and rates of maturation of the respiratory and digestive systems, the spine and the locomotor system. Our findings are relevant to understanding how changes in the relative rates of growth of these systems and structures impacted on the development and evolution of modern human body shape.

Age Estimation From Stages of Union of the Vertebral Epiphyses of the Ribs

This study attempts to fill a persistent gap in the literature by documenting the timing of epiphyseal union at the vertebral end of the ribs in a sample of modern Portuguese skeletons. The skeletal remains of 53 females and 45 males, between the ages of 11 and 30, were taken from the Lisbon documented skeletal collection. Individuals in the sample have been previously described as being representative of a middle-to-low socioeconomic segment of the early 20th century Lisbon population. Three anatomical locations were examined for epiphyseal union: the head, the articular tubercle and the nonarticular tubercle. The first epiphysis to show partial union is that of the nonarticular tubercle (females, 11-19 years; males, 11-19 years), followed by the epiphysis of the articular tubercle (females, 11-20 years; males, 16-20 years), and finally by the head epiphysis (females, 15-24 years; males, 16-22 years), which can still show incomplete epiphyseal closure at 25 and 24 years for females and males, respectively. A trend for earlier female maturation was observed, but the statistical tests only confirmed this result for some ribs and age groups. No directional asymmetry was found, but a significant fluctuating asymmetry was observed in all three epiphyses. A preliminary analysis showed that the asymmetric group of individuals in the study sample includes all the rural-to-urban migrants, relative to the symmetric group.

Three‐dimensional analysis of sexual dimorphism in human thoracic vertebrae: Implications for the respiratory system and spine morphology

Sexual dimorphism is important for intraspecific variation and well studied in the human skeleton. In the thoracic part of the spine sexual dimorphism is expected for differences in the respiratory system related to body mass, lung capacity, and energetics, and in the reproductive system for adaptations to pregnancy (lower spine lordosis, posture). However, little is known about sexual dimorphism in this anatomical region. We use three-dimensional (3D)-geometric morphometrics to test hypotheses on sexual dimorphism in the first 10 thoracic vertebrae (T1-T10). Forty-six 3D-landmarks were measured on vertebrae of 24 adult females and males of known age and sex. Results confirm that male vertebrae are consistently larger than female ones. Males show more dorsally oriented transverse processes and relatively larger vertebral bodies in upper and lower thoracic vertebrae. Sexual dimorphism in lower thoracic vertebrae affects the orientation of the spinous processes, which is more horizontal in females but more caudal in males. Such regional pattering of sexual dimorphism emerges also from principal component analyses reflecting a complex interaction between the effects of sex and serial position on shape variation. Greater dorsal orientation of male transverse processes reorients the ribs and could lead to greater radial thorax diameters. This fits with greater male respiratory capacities, but may indicate also greater invagination of the male spine within the thorax. Horizontal orientation of the spinous processes in females could allow for a greater thoraco-lumbar lordosis during pregnancy, but more comparative research is necessary to test these hypotheses.

Chronology of fusion of the primary and secondary ossification centers in the human sacrum and age estimation in child and adolescent skeletons

Little is known about fusion times of the primary and secondary centers of ossification in the sacrum, particularly from dry bone observations. In this study, the timing of union of these centers was studied in a sample of modern Portuguese skeletons (90 females and 101 males) between the ages of 0 and 30 years, taken from the Lisbon documented skeletal collection. A three-stage scheme was used to assess fusion status between ossification centers as unfused, partially fused and completely fused. Posterior probability tables of age, given a certain stage of fusion, were calculated for most anatomical locations studied using both reference and uniform priors. Partial union of primary centers of ossification was observed from 1 to 8 years of age and partial union of secondary centers of ossification was observed from 15 to 21 years of age. The first primary centers of ossification to complete fusion are the neural arch with the centrum of the fifth sacral vertebrae and the last are the costal element with the centrum of the first sacral vertebra. The annular and sacroiliac epiphyses are the first, among the secondary centers of ossification observed, to complete fusion, after which the lateral margin fuses. This study offers information on timing of fusion of diverse locations in the developing sacrum useful for age estimation of complete or fragmented immature human skeletal remains and fills an important gap in the literature, by adding to previously published times of fusion of primary and secondary ossification centers in this sample.

Age estimation from stages of epiphyseal union in the presacral vertebrae

The presacral vertebrae have various secondary centers of ossification, whose timing of fusion can be used for age estimation of human skeletal remains up to the middle to the latter third decade. However, detailed information about the age at which these secondary centers of ossification fuse has been lacking. In this study, the timing of epiphyseal union in presacral vertebrae was studied in a sample of modern Portuguese skeletons (57 females and 47 males) between the ages of 9 and 30, taken from the Lisbon documented skeletal collection. A detailed photographic record of these epiphyses and the age ranges for the different stages of epiphyseal union are provided. Partial union of epiphyses was observed from 11 to 27 years of age. In general, centers of ossification begin to fuse first in the cervical and lumbar vertebrae, followed by centers of ossification in the thoracic region. The first center of ossification to complete fusion is usually that of the mammillary process in lumbar vertebrae. This is usually followed by that of the transverse process, spinous transverse process, and annular ring, regardless of vertebra type. There were no statistically significant sex differences in timing of fusion, but there was a trend toward early maturation in females for some vertebra or epiphyses. Bilateral epiphyses did not show statistically significant differences in timing of fusion. This study offers information on timing of fusion of diverse epiphyseal locations useful for age estimation of complete or fragmented human skeletal remains.

The growth pattern of Neandertals, reconstructed from a juvenile skeleton from El Sidrón (Spain)

Neandertal growth patterns The ontogeny of different parts of the Neandertal skeleton has been derived from isolated bones and fragments. Rosas et al. present a more complete skeleton of a Neandertal child, aged 7 to 8 years, from a 49,000-year-old site in northern Spain. The skeleton preserves dental, cranial, and postcranial material, allowing the assessment of dental and skeletal maturation with age. Most of the elements indicate an overall growth rate similar to that of modern human children. The main difference between Neandertals and modern humans is in the vertebral column. Also, several features indicate ongoing brain growth. The pattern of vertebral maturation and extended brain growth might reflect the broad Neandertal body form and physiology, rather than a fundamental difference in the overall pace of growth in Neandertals. Science, this issue p. 1282 Neandertals show differential growth modulation to that of modern humans to accommodate specific brain and body form. Ontogenetic studies help us understand the processes of evolutionary change. Previous studies on Neandertals have focused mainly on dental development and inferred an accelerated pace of general growth. We report on a juvenile partial skeleton (El Sidrón J1) preserving cranio-dental and postcranial remains. We used dental histology to estimate the age at death to be 7.7 years. Maturation of most elements fell within the expected range of modern humans at this age. The exceptions were the atlas and mid-thoracic vertebrae, which remained at the 5- to 6-year stage of development. Furthermore, endocranial features suggest that brain growth was not yet completed. The vertebral maturation pattern and extended brain growth most likely reflect Neandertal physiology and ontogenetic energy constraints rather than any fundamental difference in the overall pace of growth in this extinct human.

Three-dimensional morphometrics of thoracic vertebrae in Neandertals and the fossil evidence from El Sidrón (Asturias, Northern Spain)

Well preserved thoracic vertebrae of Neandertals are rare. However, such fossils are important as their three-dimensional (3D) spatial configuration can contribute to the understanding of the size and shape of the thoracic spine and the entire thorax. This is because the vertebral body and transverse processes provide the articulation and attachment sites for the ribs. Dorsal orientation of the transverse processes relative to the vertebral body also rotates the attached ribs in a way that could affect thorax width. Previous research indicates possible evidence for greater dorsal orientation of the transverse processes and small vertebral body heights in Neandertals, but their 3D vertebral structure has not yet been addressed. Here we present 15 new vertebral remains from the El Sidrón Neandertals (Asturias, Northern Spain) and used 3D geometric morphometrics to address the above issues by comparing two particularly well preserved El Sidrón remains (SD-1619, SD-1641) with thoracic vertebrae from other Neandertals and a sample of anatomically modern humans. Centroid sizes of El Sidrón vertebrae are within the human range. Neandertals have larger T1 and probably also T2. The El Sidrón vertebrae are similar in 3D shape to those of other Neandertals, which differ from Homo sapiens particularly in central-lower regions (T6-T10) of the thoracic spine. Differences include more dorsally and cranially oriented transverse processes, less caudally oriented spinous processes, and vertebral bodies that are anteroposteriorly and craniocaudally short. The results fit with current reconstructions of Neandertal thorax morphology.

Possible Further Evidence of Low Genetic Diversity in the El Sidrón (Asturias, Spain) Neandertal Group: Congenital Clefts of the Atlas

We present here the first cases in Neandertals of congenital clefts of the arch of the atlas. Two atlases from El Sidrón, northern Spain, present respectively a defect of the posterior (frequency in extant modern human populations ranging from 0.73% to 3.84%), and anterior (frequency in extant modern human populations ranging from 0.087% to 0.1%) arch, a condition in most cases not associated with any clinical manifestation. The fact that two out of three observable atlases present a low frequency congenital condition, together with previously reported evidence of retained deciduous mandibular canine in two out of ten dentitions from El Sidrón, supports the previous observation based on genetic evidence that these Neandertals constituted a group with close genetic relations. Some have proposed for humans and other species that the presence of skeletal congenital conditions, although without clinical significance, could be used as a signal of endogamy or inbreeding. In the present case this interpretation would fit the general scenario of high incidence of rare conditions among Pleistocene humans and the specific scenariothat emerges from Neandertal paleogenetics, which points to long-term small and decreasing population size with reduced and isolated groups. Adverse environmental factors affecting early pregnancies would constitute an alternative, non-exclusive, explanation for a high incidence of congenital conditions. Further support or rejection of these interpretations will come from new genetic and skeletal evidence from Neandertal remains.