Thoracic morphology in Near Eastern Neandertals and early modern humans compared with recent modern humans from high and low altitudes

Paleoanthropologists have long noted the unique "hyper-barrel-shaped" Neandertal thorax as inferred from fragmentary ribs, clavicles, and sterna. Yet scholars disagree whether the Neandertal thorax represents an adaptation to cold climates or elevated activity levels. Given the difficulties of reconstructing overall chest shape from isolated and fragmentary thoracic skeletal elements, it is worthwhile comparing Neandertals and contemporaneous early modern human fossils from the same geographic region to recent modern human skeletons that are known to have enlarged chests. This study compares thoracic skeletal morphology in two Near Eastern Neandertals (Tabūn C1 and Shanidar 3) and two early modern humans from the same region (Skhūl IV and V) with four samples of recent modern human skeletons from the Andes (n=347): two coastal groups and two groups from high altitudes. The two highland groups, similar to their living descendants, exhibit morphological evidence of anteroposteriorly deep and mediolaterally wide chests as part of respiratory adaptations to high-altitude hypoxia. I calculated the percentage of deviation of each Neandertal and early modern human fossil from the means of the four recent modern human samples for clavicle and rib lengths and curvatures. Shanidar 3 and Tabūn C1 exhibit ribs that are slightly larger and less curved than the Andean samples, indicating slightly larger thoracic skeletons than modern humans who are known to have enlarged chests in response to increased respiratory demands. Skhūl IV and V have significantly shorter ribs with greater curvature suggesting especially narrow thoracic skeletons. Comparisons with Andean populations suggest that the enlarged thoraces of Neandertals may reflect high activity levels, although results from this study do not exclude cold adaptation as an explanatory factor.     

Intercostal variation for age estimation--are the standards for the right 4th rib applicable for other ribs?

Age estimation of unknown skeletal remains is very important in forensic medicine. Morphologic methods are fast and easy to use for purpose of age determination. The sternal ends of the ribs are a reliable method of age estimation from late adolescence to old age. Iscan et al developed a phase analysis method for the right 4th rib that was sex and race specific. The purpose of this study is to determine the accuracy of the standards of age estimation from the right 4th and other rib using the phase analysis for the Turkish population. The sample consisted of right and left 3rd, 4th and 5th ribs from 34 Turkish women and 76 men. There were statistically significant variations found on the right 5th, left 3rd, 4th, and 5th ribs according to these standards in men for phases 5, 6, and 7. For women, all the right and left ribs included in this study were in concordance with right 4th rib standards in all phases.     

Thoracic skeletal morphology and high-altitude hypoxia in Andean prehistory

Living humans from the highland Andes exhibit antero-posteriorly and medio-laterally enlarged chests in response to high-altitude hypoxia. This study hypothesizes that morphological responses to high-altitude hypoxia should also be evident in pre-Contact Andean groups. Thoracic skeletal morphology in four groups of human skeletons (N = 347) are compared: two groups from coastal regions (Ancón, Peru, n = 79 and Arica, Chile, n = 123) and two groups from high altitudes (San Pedro de Atacama, Chile, n = 102 and Machu Picchu and Cuzco, Peru, n = 43). Osteometric variables that represent proportions of chest width and depth include sternal and clavicular lengths and breadths and rib length, curvature, and area. Each variable was measured relative to body size, transformed into logarithmic indices, and compared across sex-specific groups using ANOVA and Tukey multiple comparison tests. Atacama highlanders have the largest sternal and clavicular proportions and ribs with the greatest area and least amount of curvature, features that suggest an antero-posteriorly deep and mediolaterally wide thoracic skeleton. Ancón lowlanders exhibit proportions indicating narrower and shallower chests. Machu Picchu and Cuzco males cluster with the other highland group in rib curvature and area at the superior levels of the thorax, whereas chest proportions in Machu Picchu and Cuzco females resemble those of lowlanders. The variation in Machu Picchu and Cuzco males and females is interpreted as the result of population migrations. The presence of morphological traits indicative of enlarged chests in some highland individuals suggests that high-altitude hypoxia was an environmental stressor shaping the biology of highland Andean groups during the pre-Contact period.     

Use of conical wire arrays for modeling three-dimensional MHD implosion effects

Results are presented from experimental studies and numerical simulations of three-dimensional dynamics of the plasma produced in the Angara-5-1 facility by the electrical implosion of conical wire arrays at currents of up to 3 MA. The arrays were made of 6-to 8-μm-diameter tungsten wires, the inclination angle of the generatrix with respect to the axis being from 15° to 42°. The results of two-dimensional MHD simulations are compared with experimental data. The formation dynamics of the plasma precursor is found to be different for cylindrical and conical arrays. As the cone angle increases, the duration of the X-ray pulse increases, while the height of the pinch radiating zone decreases.     

Thoracic skeletal defects and cardiac malformations: A common epigenetic link?

Congenital heart defects (CHDs) are the most common birth defects in humans. In addition, cardiac malformations represent the most frequently identified anomaly in teratogenicity experiments with laboratory animals. To explore the mechanisms of these drug-induced defects, we developed a model in which pregnant rats are treated with dimethadione, resulting in a high incidence of heart malformations. Interestingly, these heart defects were accompanied by thoracic skeletal malformations (cleft sternum, fused ribs, extra or missing ribs, and/or wavy ribs), which are characteristic of anterior-posterior (A/P) homeotic transformations and/or disruptions at one or more stages in somite development. A review of other teratogenicity studies suggests that the co-occurrence of these two disparate malformations is not unique to dimethadione, rather it may be a more general phenomenon caused by various structurally unrelated agents. The coexistence of cardiac and thoracic skeletal malformations has also presented clinically, suggesting a mechanistic link between cardiogenesis and skeletal development. Evidence from genetically modified mice reveals that several genes are common to heart development and to formation of the axial skeleton. Some of these genes are important in regulating chromatin architecture, while others are tightly controlled by chromatin-modifying proteins. This review focuses on the role of these epigenetic factors in development of the heart and axial skeleton, and examines the hypothesis that posttranslational modifications of core histones may be altered by some developmental toxicants.     

Lumbar anomalies in the Shanidar 3 Neandertal

Recent examination of the Shanidar 3 remains revealed the presence of anomalous bilateral arthroses in the lumbar region. This paper describes this developmental anomaly, as well as several degenerative changes and offers potential etiologies.The Shanidar 3 remains represent an adult male Neandertal, approximately 35–50 years of age, dating to the Last Glacial. Although the partial skeleton is fragmentary, preserved elements include an almost complete set of ribs, portions of all thoracic vertebrae, all lumbar vertebrae, and the sacrum. Vertebral articulations from S1–T1 can be confidently assigned. The vertebra designated L1 is well preserved but lacks transverse processes. Instead, well defined bilateral articular surfaces, rather than transverse processes, are located on the pedicles. The skeletal elements associated with the anomalous L1 articulations were not recovered.The most likely interpretation is that the arthroses in question represent the facets for a 13th pair of ribs, a rare condition in modern hominid populations. Such lumbar developmental anomalies are an infrequent expression of a larger complex of cranial-caudal border shifting seen in the vertebral column. These shifts result in a change in the usual boundaries between the distinctive vertebral regions and are responsible for the majority of variability present in the vertebral column.     

Skeletal muscle lactate dehydrogenase isozyme alterations in men and women marathon runners

Total lactate dehydrogenase (LD) and LD isozyme activities in gastrocnemius muscle from trained men and women runners were measured in response to the chronic stress of training for a marathon race (42.2 km). Following 9 wk of training, total LD activity in skeletal muscle from men and women runners significantly (P less than 0.02) decreased 2.26 and 2.25 U/mg protein, respectively. However, men's total LD activities were significantly (P less than 0.001) less than the women's both before and after training. Significant (P less than 0.05) increases in LD1 activities in skeletal muscle in men and women runners were also observed after training. No significant correlations were detected between percent fiber type composition in men or women vs. the changes in total LD activity, changes in LD1 activity, maximal O2 consumption or training distance averaged per week after the training period. The biochemical adaptations in skeletal muscle that occurred in the LD isozyme composition in both men and women runners make the runners skeletal muscle appear similar to heart muscle in LD1 and LD2 activities.     

Direct observation of protein secondary structure in gas vesicles by atomic force microscopy.

The protein that forms the gas vesicle in the cyanobacterium Anabaena flos-aquae has been imaged by atomic force microscopy (AFM) under liquid at room temperature. The protein constitutes "ribs" which, stacked together, form the hollow cylindrical tube and conical end caps of the gas vesicle. By operating the microscope in deflection mode, it has been possible to achieve sub-nanometer resolution of the rib structure. The lateral spacing of the ribs was found to be 4.6 +/- 0.1 nm. At higher resolution the ribs are observed to consist of pairs of lines at an angle of approximately 55 degrees to the rib axis, with a repeat distance between each line of 0.57 +/- 0.05 nm along the rib axis. These observed dimensions and periodicities are consistent with those determined from previous x-ray diffraction studies, indicating that the protein is arranged in beta-chains crossing the rib at an angle of 55 degrees to the rib axis. The AFM results confirm the x-ray data and represent the first direct images of a beta-sheet protein secondary structure using this technique. The orientation of the GvpA protein component of the structure and the extent of this protein across the ribs have been established for the first time.     

The lumbar and sacrum movement pattern during the back squat exercise

An essential exercise for strength training of the lower limbs is the squat exercise. During this exercise, changes in lumbar lordosis are commonly used to indicate when the descent of the squat should cease, yet the behavior of the lumbar-scarum segments remains unclear. The purpose of this study was to quantify the lumbar-sacrum movements during the back squat, because the movement of the sacrum is influenced by the width of stance, this variable was also investigated. Thirty trained subjects, 18 men with 1 repetition maximum (1RM) squat of 123% (13.9%) of bodyweight and 12 women with 1RM squat of 93% (15.6%), performed a set of narrow and wide stance squats, each carrying an additional 50% of body weight as load. The timing and movement of the lumbar angle (T12/L1), sacrum angle (L5/S1), and lumbar flexion angle (lumbar lordosis) were measured in 3 dimensions for the ascent and decent phases. Men and women achieved similar lumbar angles for both width of stance and phase. Sacrum angles, lumbar flexion angles, and timing differed significantly (p < 0.05) between gender and width of stance. The lumbar flexion range during the descent phase for women in narrow and wide stance was 12.9° and 12.6°, respectively; for men, this range was significantly (p < 0.05) larger at 26.3° and 25.4°, respectively. Men and women developed different movement patterns for the squatting movement, and therefore, this needs to be considered in strength development and screening procedures. The lumbar spine became kyphotic as soon as a load was placed on the shoulders, and any teaching cues to maintain a curved lumbar spine when squatting must be questioned.     

Relationship between scapular position and structural strength of rib cage in quadruped animals

Determining scapular position is a major issue in reconstructing the skeletal systems of extinct quadruped archosaurs and mammals, because the proximal portion of the scapulae has no direct skeletal joint with the vertebrae or ribs. When quadrupeds stand or walk, their trunk is suspended between the forelimbs by the serratus muscles, which arises from the lateral sides of the “thoracic” ribs and inserts into the proximal portion of the costal surface of the scapula. Therefore, the “thoracic” ribs are subjected to a static or dynamic vertical compression between the lifting force from the muscle and the gravitational force from the vertebral column. To investigate the body support function of the ribs, we analyzed the mechanical strength of the ribs of extant tetrapods by the two‐dimensional finite element method, and compared the degree of strength through their craniocaudal scapular positions. The result of this simulation showed that the “thoracic” ribs of quadrupeds, to which the serratus muscles attach, have a relatively higher strength against compaction than the other ribs. In bipeds, however, we did not find a similar correlation between the strength of ribs and the serratus muscle. This implies that the location of robust ribs is associated with the arrangement of the serratus muscle, and provides a probable candidate for determination of the scapular position for extinct quadruped archosaurs and mammals. J. Morphol. 2009. © 2009 Wiley‐Liss, Inc.     

Broken ribs: Paleopathological analysis of costal fractures in the human identified skeletal collection from the Museu Bocage,Lisbon, Portugal (late 19th to middle 20th centuries)

Although rarely reported in the anthropological literature, rib fractures are commonly found during the analysis of human skeletal remains of past and modern populations. This lack of published data precludes comparison between studies and restricts an accurate understanding either of the mechanisms involved in thoracic injuries or their impact on past societies. The present study aimed: 1) to report rib fracture prevalence in 197 individuals, 109 males, and 88 females, with ages at death ranging from 13 to 88 years old, from the Human Identified Skeletal Collection, Museu Bocage, Portugal (late 19th‐middle 20th centuries); 2) to test the hypothesis that a higher prevalence of rib stress fractures existed in the 133 individuals who died from respiratory diseases, in a period before antibiotics. The macroscopic analysis revealed 23.9% (n = 47) of individuals with broken ribs. 2.6% (n = 124) out of 4,726 ribs observed were affected. Males presented more rib fractures, and a significantly higher prevalence was noted for older individuals. Fractures were more frequently unilateral (n = 34), left sided (n = 19) and mainly located on the shaft of ribs from the middle thoracic wall. Nineteen individuals presented adjacent fractured ribs. Individuals who died from pulmonary diseases were not preferentially affected. However, a higher mean rate of fractures was found in those who died from pneumonia, a scenario still common nowadays. Since rib involvement in chest wall injury and its related outcomes are important issues both for paleopathology and forensic anthropology, further investigations are warranted. Am J Phys Anthropol 2009. © 2009 Wiley‐Liss, Inc.     

On the trail of pulmonary tuberculosis based on rib lesions: results from the Human Identified Skeletal Collection from the Museu Bocage (Lisbon, Portugal)

In the last 20 years, studies on human identified skeletal collections have revealed a significant relationship between new bone formation on the visceral surface of ribs and pulmonary tuberculosis (TB). To improve methods of differential diagnosis of respiratory diseases in archaeological skeletons, an investigation was conducted on 197 individuals from the Human Identified Skeletal Collection of the Museu Bocage (Lisbon, Portugal). This sample included 109 males and 88 females who lived during the 19th-20th centuries, with ages at death ranging from 13-88 years. The skeletons were grouped according to cause of death: 1) pulmonary TB (N = 84); 2) pulmonary non-TB diseases (N = 49); and 3) a control group (N = 64) composed of individuals randomly selected among the extrapulmonary non-TB causes of death. The ribs, sterna, scapulae, and clavicles were macroscopically observed. New bone formation on the visceral surface of ribs was recorded in 90.5% (76/84) of individuals who died from pulmonary TB, in 36.7% (18/49) with a pulmonary non-TB disease as cause of death, and in 25.0% (16/64) of the control group. These differences were statistically significant (P < 0.001). Furthermore, in individuals with pulmonary TB, the bony lesions presented mainly as lamellar bone on the vertebral end of the upper and middle thoracic rib cage. Proliferative alterations also occurred on one sternum and in nine clavicles and eight scapulae. This work strongly supports the results of similar studies performed on other documented collections, suggesting that new bone formation on ribs, although not pathognomonic, is a useful criterion for the differential diagnosis of pulmonary TB.     

Bilateral Thoracic Outlet Syndrome from Anomalous 8th Cervical Vertebrae Ribs

Thoracic outlet syndrome (TOS) is a group of diverse disorders resulting from compression of neurovascular structures as they pass from the lower neck to upper limb. Neurological symptoms, such as pain, weakness, or paraesthesia, are much more common than vascular symptoms such as pallor or venous congestion. Anatomical abnormalities can contribute to this condition. Thirty percent of patients with TOS can have a cervical rib, arising from the transverse process of the 7th cervical vertebra, compared with 1% of the general population. We report the first case in the literature of neurogenic TOS from a cervical rib arising from a supernumerary 8th cervical vertebra. This patient had immediate improvement in TOS symptoms following scalene muscle surgery and resection of cervical and first thoracic ribs.     

Analysis of quantitative methods for rib seriation using the Spitalfields documented skeletal collection

Accurate rib seriation is essential in forensic anthropology and bioarchaeology for determination of minimum numbers of individuals, sequencing trauma patterns to the chest, and identification of central ribs for use in age estimation. We investigate quantitative methods for rib seriation based on three metric variables: superior (anterior) costo-transverse crest height (SCTCH), articular facet of the tubercle-to-angle length (AFTAL), and head-to-articular facet length (HAFL). The sample consists of complete but unseriated sets of ribs from 133 individuals from the documented (known age and sex) and undocumented skeletal collections of Christ Church Spitalfields, London. This research confirms the results of an earlier study (Hoppa and Saunders [1998] J. Forensic. Sci. 43:174-177) and extends it with the application of two new metric traits and further analyses of sex differences. Analyses of variance showed that SCTCH and AFTAL are significantly associated (P < 0.001) with rib number. Tukey tests of pairwise rib comparisons revealed that for two dimensions (SCTCH and AFTAL), the central ribs (3rd-6th) are significantly distinct from each other (P < 0.05). Using simple ranking of either the SCTCH or AFTAL traits, the proportion of correctly identified ribs within +/-1 position was 80%, compared to initial seriation using morphological methods (Dudar [1993] J. Forensic. Sci. 28:788-797; Mann [1993] J. Forensic. Sci. 28:151-155). Significant sex dimorphism was also identified for these two traits. Analysis of the HAFL trait produced somewhat equivocal results, suggesting that this variable is not reliable for rib seriation. The variable SCTCH proves to be the most useful dimension for seriation, and shows that all but the 7th-9th ribs can be distinguished from others in the sequence, with important results for the 4th rib, where ranking allowed identification in 86% of cases, consistent with morphological methods for intact ribs.     

Theoretical aspects of surface-to-volume ratios and water-storage capacities of succulent shoots

Surface-to-volume (S/V) ratios of drought-adapted plants affect transpiration, photosynthesis, and water-storage capacity. The S/V ratio of cladodes and flat leaves is S/V = 2/T, where T is thickness: even slight thickening greatly reduces S/V. During rain/drought cycles succulent stems swell and shrink without tearing by having flexible ribs, but ribs increase S/V above that of a smooth cylindrical stem with equal volume: the increased surface area is S(ribbed)/S(cylindrical) = N[x + (π/N)]/π(1 + x), where N is number of ribs and x is rib height relative to the radius of the inner stem. Numerous low ribs provide moderate expandability (storage volume) with little increase in S/V and are adaptive where droughts are short. Tall ribs provide greater expandability but greatly increase S/V and probably are adaptive only in mesic habitats. Having ～8-15 ribs, each about as tall as the inner stem radius, provides large storage capacity and intermediate increase in S/V. By increasing absolute size, S/V is reduced so greatly that even large ribs can have an S/V smaller than that of a narrow cylindrical or spherical stem with less volume.     

Motion of nonaxisymmetric red blood cells in cylindrical capillaries

We analyze theoretically the single-file flow of asymmetric red blood cells along cylindrical capillaries. Red cells in narrow capillaries are typically nonaxisymmetric, with the cell membrane moving continuously around the cell. In our analysis, cell shape and streamlines of membrane motion are prescribed. Lubrication theory is used to compute velocities and pressures in the fluid surrounding the cell. Conditions of zero lift, zero torque, zero drag, and energy conservation in the cell are imposed. Predicted tank-treading frequency, cell inclination and transverse displacement are small. Cell asymmetry and tank-treading are found to have little effect on the apparent viscosity of blood in capillaries with diameters up to 7 microns.     

23种伞形科植物果实形态及其分类学意义

该实验采用徒手切片法对伞形科17属23种植物的果实进行了外部形态和解剖特征的观察,结果表明:伞形科果实有背腹压扁、两侧压扁和不压扁3种类型;侧棱有宽、有窄;油管的分布有棱槽单油管型和棱槽多油管型;花柱基多数为圆锥状,少数种的花柱基为扁平垫状;萼齿明显或不明显。通过进一步对属间和属内果实解剖特征的比较得出:(1)果实表面被钩刺或刚毛及果棱特征在属间差异明显,在属内表现出一致性,可作为伞形科属间分类的依据。(2)果实横切面的形状、胚乳腹面的凹凸以及萼齿的形态特征在属内种间的分类研究中有重要的意义。基于果实形态特征,编制了17属23种植物的分种检索表。     

新疆克拉玛依市维吾尔族和汉族成年人体部体质特征

为探讨新疆克拉玛依市维吾尔族与汉族成年人体部体质特征。采用整群分层随机抽样原则,按照《国民体质测试指导站各指标的测试方法及判断标准》规定的方法,测量并获得新疆克拉玛依市维吾尔族、汉族20~59岁共4108个成年人的有效样本,并按Martin法对所测体部项目进行体质特征研究。新疆克拉玛依市维吾尔族:除肩型男性为中肩型、女性为窄肩型外,男女均为超中等身材、宽胸型、宽骨盆型、窄手型、矮胖型。新疆克拉玛依市汉族:除身材分型男性为高型、女性为超中等身材外,男女均为宽胸型、窄肩型、宽骨盆型、窄手型、中间胖瘦型。维吾尔族与汉族之间体质特征总体水平差异具有统计学意义(p<0.01),且差异主要存在于维吾尔族与汉族女性之间。克拉玛依市维吾尔族和汉族成年人体质特征均具有北方人群的体质特征。     

The skeletal kinematics of lung ventilation in three basal bird taxa (emu, tinamou, and guinea fowl)

In vivo visceral and skeletal kinematics of lung ventilation was examined using cineradiography in two palaeognaths, the emu (Dromaius novaehollandiae) and the Chilean tinamou (Nothoprocta perdicaria), and a basal neognath, the helmeted guinea fowl (Numida meleagris). Upon inspiration, the thorax expands in all dimensions. The vertebral ribs swing forward and upward, thereby increasing the transverse diameter of the trunk. The consistent location of the parapophysis throughout the dorsal vertebral series, ventral and cranial to the diapophysis, ensures a relatively uniform lateral expansion. An increase in the angle between the vertebral and the sternal ribs causes the sternal ribs to push the sternum ventrally. Owing to the greater length of the caudal sternal ribs, the caudal sternal margin is displaced further ventrally than the cranial sternal margin. When observed in lateral view, sternal movement is not linear, but elliptical. The avian thorax is highly constrained in its movement when compared with crocodylians, the other extant archosaur clade. Birds lack a lumbar region and intermediate ribs. Sternal ribs are completely ossified, and have a bicondylar articulation with the sternum. Considering the importance of pressure differences between cranial and caudal air sac complexes for the generation of unidirectional air flow in the avian lung, it is hypothesized that a decrease in the degrees of freedom of movement of the avian trunk skeleton, greater expansion of the ventrocaudal trunk region, and elliptical sternal movement may represent specific adaptations for fine-tuned control over air flow within the complex avian pulmonary system.     

Autonomic dysreflexia during sperm retrieval in spinal cord injury: influence of lesion level and sildenafil citrate.

Autonomic dysreflexia (AD) can occur during penile vibratory stimulation in men with spinal cord injury, but this is variable, and the association with lesion level is unclear. The purpose of this study was to characterize the cardiovascular responses to penile vibratory stimulation in men with spinal cord injury. We hypothesized that those with cervical injuries would demonstrate a greater degree of AD compared with men with thoracic injuries. We also questioned whether the rise in blood pressure could be attenuated by sildenafil citrate. Participants were classified as having cervical (n = 8) or thoracic (n = 5) injuries. While in a supine position, subjects were instrumented with an ECG, and arterial blood pressure was determined beat by beat. Subjects reported to the laboratory twice and received an oral dose of sildenafil citrate (25-100 mg) or no medication. Penile vibratory stimulation was performed using a handheld vibrator to the point of ejaculation. At ejaculation during the nonmedicated trials, the cervical group had a significant decrease in heart rate (-5-10 beats/min) and increase in mean arterial blood pressure (+70-90 mmHg) relative to resting conditions, whereas the thoracic group had significant increases in both heart rate (+8-15 beats/min) and mean arterial pressure (+25-30 mmHg). Sildenafil citrate had no effect on the change in heart rate or mean arterial pressure in either group. In summary, men with cervical injuries had more pronounced AD during penile vibratory stimulation than men with thoracic injuries. Administration of sildenafil citrate had no effect on heart rate or blood pressure during penile vibratory stimulation in men with spinal cord injury.