Pelvic and neonatal size correlations in light of evolutionary hypotheses.

OBJECTIVE: This study aimed to analyze the correlations between maternal size, neonatal size, and gestational variables. METHODS: Our sample comprises 131 mother-infant dyads. We investigated correlations between five neonatal traits (gestational age, birthweight, head, suboccipito-brematic, and abdominal girths), three maternal traits (height, BMI, and uterus height), and three pelvic variables (conjugate, inter-spinous diameters, and sub-pubic angle) using computed tomography pelvimetry. RESULTS: We found that the five neonatal traits were significantly intercorrelated. BMI was not correlated with neonatal traits while maternal height was correlated with birthweight, suboccipito-brematic, and abdominal girth. In the multiple regression models, gestational age was correlated with birthweight, head, and abdominal girth. Among the neonatal and pelvimetry correlations, conjugate diameter was slightly correlated with suboccipito-bregmatic girth, but inter-spinous and sub-pubic angle were not correlated with neonatal traits. Uterus height predicted all neonatal variables, but it was not correlated with gestational age. DISCUSSION: Our results suggest that fetal growth is shaped by maternal phenotype rather than external ecological factors. The association of the inlet size with suboccipito-bregmatic girth reflects the tight fit between the neonatal brain and the maternal pelvis dimensions, an adaptation that would reduce the risk of cephalo-pelvic disproportion, while the absence of tight fit at the midplane and outlet could be due to the effect of the pelvic relaxation. Uterus distention is not the only mechanism involved in the initiation of parturition. Birth and pregnancy are complex processes and we suggest that maternal-neonatal associations are the result of a combination of multiple obstetric tradeoffs.

Technical standards for respiratory oscillometry.

Oscillometry (also known as the forced oscillation technique) measures the mechanical properties of the respiratory system (upper and intrathoracic airways, lung tissue and chest wall) during quiet tidal breathing, by the application of an oscillating pressure signal (input or forcing signal), most commonly at the mouth. With increased clinical and research use, it is critical that all technical details of the hardware design, signal processing and analyses, and testing protocols are transparent and clearly reported to allow standardisation, comparison and replication of clinical and research studies. Because of this need, an update of the 2003 European Respiratory Society (ERS) technical standards document was produced by an ERS task force of experts who are active in clinical oscillometry research.The aim of the task force was to provide technical recommendations regarding oscillometry measurement including hardware, software, testing protocols and quality control.The main changes in this update, compared with the 2003 ERS task force document are 1) new quality control procedures which reflect use of "within-breath" analysis, and methods of handling artefacts; 2) recommendation to disclose signal processing, quality control, artefact handling and breathing protocols (e.g. number and duration of acquisitions) in reports and publications to allow comparability and replication between devices and laboratories; 3) a summary review of new data to support threshold values for bronchodilator and bronchial challenge tests; and 4) updated list of predicted impedance values in adults and children.

Epinephrine but not vasopressin attenuates the airway response to anaphylactic shock in rats.

PURPOSE: The two life-threatening signs of anaphylactic shock (AS) are severe arterial hypotension and bronchospasm. Guidelines recommend epinephrine as first-line treatment. Arginine vasopressin (AVP) has been proposed as an alternative if epinephrine does not correct arterial hypotension. These two drugs may have beneficial, neutral or deleterious effects on airflow either directly or by modifying factors that regulate vasodilatation and/or edema in the bronchial wall. AIM OF THE STUDY: To compare the effects of epinephrine and AVP on airflow and airway leakage in a rat model of AS. MATERIALS AND METHODS: Thirty-two ovalbumin-sensitized rats were randomized into four groups: control (CON), AS without treatment (OVA), AS treated with epinephrine (EPI), and AS treated with AVP (AVP). Mean arterial pressure (MAP), respiratory resistance and elastance and microvascular leakage in the airways were measured. RESULTS: All OVA rats died within 20 minutes following ovalbumin injection. Ovalbumin induced severe arterial hypotension and airway obstruction (221 ± 36 hPa.s.L-1 vs. vehicle 52 ± 8 hPa.s.L-1; p < 0.0001) associated with microvascular leakage distributed throughout the trachea, bronchi and intra-pulmonary airways. EPI and AVP extended survival time; EPI restored a higher level of MAP than AVP. Airway obstruction was attenuated by epinephrine (146 ± 19 hPa.s.L-1; p < 0.0001), but not by AVP (235 ± 58 hPa.s.L-1; p = 0.42). CONCLUSIONS: Epinephrine was superior to AVP for alleviating the airway response in a rat model of AS. When bronchospasm and severe arterial hypotension are present during AS, epinephrine should be the drug of choice.

Breathing-related changes of respiratory resistance in vocal cord dysfunction.

Vocal cord dysfunction induced by exercise in children with uncontrolled asthma was identified by laryngoscopy. The paradoxical adduction of the vocal cords was also indicated by the breathing-related changes of the forced oscillation respiratory resistance showing prominent increase during inspiration and a large positive difference between inspiration and expiration. The breathing-related changes of respiratory resistance offer thus a useful first-line technique to diagnose vocal cord dysfunction.

Obstetrical Constraints and the Origin of Extended Postnatal Brain Maturation in Hominin Evolution.

The origin of difficult birth is still a matter of debate in obstetrics. Recent studies hypothesized that early hominins already experienced obstructed labor even with reduced neonatal head sizes. The aim of this work is to test this hypothesis using an extant obstetrical sample with known delivery outcomes. Three delivery outcomes (i.e., instrument-assisted, Caesarean section, and vaginal birth) were evaluated using a discriminant analysis based on 131 mother-baby dyads and 36 feto-pelvic variables. This obstetrical sample was compared with 20 australopithecine "dyads" generated from the combination of six pelvic reconstructions (three for Australopithecus afarensis, two for A. africanus, and one for A. sediba) and three fetal head size estimations. The obstetrical analysis revealed that dystocic births can be predicted by pelvic features such as an anteroposteriorly flattened pelvic inlet. Australopithecines shared these pelvic morphologies with humans and had eutocic birth only for infants of 110 g brain size or smaller, equaling a human-like neonatal/adult brain size ratio of 25-28%. Although birth mechanism cannot be deduced, the newborn/adult brain size ratio was likely more human-like than previously thought, suggesting that australopithecines were secondarily altricial to circumvent instances of obstructed labor and subsequently require a prolonged postnatal brain growth period, implying some aspects of life history pattern similar to modern humans.

New insights into patterns of integration in the femur and pelvis among catarrhines.

OBJECTIVES: Integration reflects the level of coordinated variation of the phenotype. The integration of postcranial elements can be studied from a functional perspective, especially with regards to locomotion. This study investigates the link between locomotion, femoral structural properties, and femur-pelvis complex morphology. MATERIALS AND METHODS: We measured (1) morphological integration between femoral and pelvic morphologies using geometric morphometrics, and (2) covariation between femoral/pelvic morphologies and femoral diaphyseal cross-sectional properties, which we defined as morpho-structural integration. Morphological and morpho-structural integration patterns were measured among humans (n = 19), chimpanzees and bonobos (n = 16), and baboons (n = 14), whose locomotion are distinct. RESULTS: Baboons show the highest magnitude of morphological integration and the lowest of morpho-structural integration. Chimpanzees and bonobos show intermediate magnitude of morphological and morpho-structural integration. Yet, body size seems to have a considerable influence on both integration patterns, limiting the interpretations. Finally, humans present the lowest morphological integration and the highest morpho-structural integration between femoral morphology and structural properties but not between pelvic morphology and femur. DISCUSSION: Morphological and morpho-structural integration depict distinct strategies among the samples. A strong morphological integration among baboon's femur-pelvis module might highlight evidence for long-term adaptation to quadrupedalism. In humans, it is likely that distinct selective pressures associated with the respective function of the pelvis and the femur tend to decrease morphological integration. Conversely, high mechanical loading on the hindlimbs during bipedal locomotion might result in specific combination of structural and morphological features within the femur.

Exercise-induced bronchoconstriction in school-age children born extremely preterm.

BACKGROUND: School children born preterm often show airway hyperresponsiveness to methacholine or histamine. Less attention has been paid to their airway response to exercise, an important point because of the role of exercise in the child's daily life. The aim of this study was to describe the characteristics of, and potential determinants to, the airway response to exercise in children born extremely preterm. METHODS: Forty-two nonasthmatic nonatopic children born before 32 wk gestation were compared with 27 healthy nonasthmatic nonatopic term children at age 7. Spirometry and respiratory impedance were measured at baseline and repeated after a single-step 6-min treadmill exercise in a climate-controlled room. RESULTS: The preterm group showed significant broncho-constriction induced by exercise. Prematurity, but not low baseline lung function, neonatal oxygen supplementation, mechanical ventilation, chronic lung disease, or maternal smoking, was a determinant of exercise-induced bronchoconstriction. CONCLUSION: Children born extremely preterm present significant exercise-induced airway obstruction at age 7. The response has different characteristics from that occurring in asthmatics and is likely to express airway noneosinophilic inflammation.

The impact of femoral rotation on sacroiliac articulation during pregnancy. Is there evidence to support Farabeuf's hypothesis by finite element modelization?

BACKGROUND: Counter-nutation movement is deemed crucial during the management of the birth process. It is a combination of lateral ilia expansion and backward displacement of the promontory resulting from the external rotations of the femurs producing an enlargement of the pelvic inlet. However, since its description by Farabeuf, this mechanism has never been challenged and analyzed in a dynamic finite element study. METHODS: Based on a female pelvic mesh and sacroiliac ligaments, we simulated external rotations of both femurs with imposed rotation of the two acetabulum centers. We hypothesize that lateral ilia expansion generates a sacrum movement resulting in a backward displacement of the promontory and a pelvic inlet enlargement. RESULTS: Finite element simulation confirms our hypothesis and reveals that ilio-sacro-transverse and axile ligaments play an essential role in this mechanism. Indeed, the increase in stiffness (ranging from 500 MPa to 750 MPa) of these ligaments accentuates the counter-nutation movement and the opening of the inlet. Instead of the anatomic congruence between the ilium and the sacrum, the sacroiliac ligaments may explain the counter-nutation. After a 6° of femur rotation, the inlet area increases to 11 cm2 (141 cm2 vs. 130 cm2). This enlargement could be noteworthy in case of obstructed labor or shoulder dystocia. Moreover, the association between external rotation and flexion of the femurs could be more efficient for opening the pelvic inlet. CONCLUSIONS: Our result did not support the original assumption of Farabeuf. By revealing how postural adjustment increases the bony birth canal, this study provides essential information for the clinical management of the delivery.

Development of bipedal walking in olive baboons, Papio anubis: A kinematic analysis.

OBJECTIVE: Although extant nonhuman primates are not habitual bipeds, they are able to walk bipedally from an early age. In humans, children improve their walking skills through developmental processes and learning experience. In nonhuman primates, infants do not routinely experience bipedalism and their musculoskeletal system gradually specializes for other locomotor modes. The aim of this study is to explore the development of occasional bipedal walking in olive baboon and to test whether the postural adjustments change with age. MATERIALS AND METHODS: We collected kinematics and spatiotemporal parameters of bipedal gait in an ontogenetic sample of 24 baboons. Data were collected at the primatology station of the CNRS (France) and a total of 47 bipedal strides were extracted for the present analysis. RESULTS: Adults and adolescents walk bipedally in the same way, and the average kinematic pattern is similar across the age-classes. Infants walk bipedally with longer duty factor, they present larger movement amplitude of the thigh and the amplitude of the knee joint decreases with speed. In contrast, older baboons increase the amplitude of the knee and ankle joints with speed. DISCUSSION: In a non-adapted biped, the postural adjustments of bipedal walking vary with age. In infant baboons, the balance requirements are likely to be higher and these are solved by adopting a "blocking strategy". In older baboons, the postural adjustments are focused on the lower limb and the movements increase with speed. These results may echo, in some respects, the developmental sequence of the intersegmental coordination described in the ontogeny of human locomotion.

A Physical Analog to Assess Surgical Face Mask Air Flow Resistance During Tidal Ventilation.

A large variety of disposable face masks have been produced since the onset of the COVID-19 pandemic. Decreased resistance to inspiration improves adherence to the use of the mask; the so called breathability is usually estimated by the measurement of air flow across a section of the tissue under a given pressure difference. We hypothesized that the mask pressure-flow relationship studied in conditions that mimic tidal breathing could allow a more comprehensive characterization of airflow resistance, a major determinant of mask comfort. A physical analog was made of a plaster cast dummy head connected through a pneumotachograph to a series of bellows inflated/deflated by a respirator. Pressure was measured at the mock airway opening over which the mask was carefully secured. The precision of the measurement equipment was quantified using two estimates of measurement error: repeatability coefficient (RC) and within-mask coefficient of variation (CVwm). The airflow resistance of 10 surgical masks was tested on 4 different days. Resistance means did not differ significantly among four repeated measures (0.34 hPa.s.L-1; 0.37 hPa.s.L-1; 0.37 hPa.s.L-1; and 0.37 hPa.s.L-1; p = 0.08), the estimated RC was 0.08 hPa.s.L-1 [95%CI: 0.06-0.10 hPa.s.L-1], and CVwm was 8.7% [95%CI: 1.5-12.2%]. Multiple comparisons suggest the presence of a learning effect by which the operator reduced the error over the course of repetitive resistance measurements. Measurement precision improved considerably when the first set of measures was not taken into account [RC ~ 0.05 hPa.s.L-1 (95%CI: 0.03-0.06 hPa.s.L-1); CVwm~4.5% (95%CI: 1.9-6.1%)]. The testing of the face mask resistance (R) appears simple and highly repeatable in conditions that resemble tidal breathing, once operator training was assured. The procedure adds further to the current standard assessment of breathability and allows estimating the maximal added respiratory load, about 10-20% of the respiratory resistance reported in heathy adult subjects.

Dynamic finite-element simulations reveal early origin of complex human birth pattern.

Human infants are born neurologically immature, potentially owing to conflicting selection pressures between bipedal locomotion and encephalization as suggested by the obstetrical dilemma hypothesis. Australopithecines are ideal for investigating this trade-off, having a bipedally adapted pelvis, yet relatively small brains. Our finite-element birth simulations indicate that rotational birth cannot be inferred from bony morphology alone. Based on a range of pelvic reconstructions and fetal head sizes, our simulations further imply that australopithecines, like humans, gave birth to immature, secondary altricial newborns with head sizes smaller than those predicted for non-human primates of the same body size especially when soft tissue thickness is adequately approximated. We conclude that australopithecines required cooperative breeding to care for their secondary altricial infants. These prerequisites for advanced cognitive development therefore seem to have been corollary to skeletal adaptations for bipedal locomotion that preceded the appearance of the genus Homo and the increase in encephalization.

Clinical significance and applications of oscillometry.

Recently, "Technical standards for respiratory oscillometry" was published, which reviewed the physiological basis of oscillometric measures and detailed the technical factors related to equipment and test performance, quality assurance and reporting of results. Here we present a review of the clinical significance and applications of oscillometry. We briefly review the physiological principles of oscillometry and the basics of oscillometry interpretation, and then describe what is currently known about oscillometry in its role as a sensitive measure of airway resistance, bronchodilator responsiveness and bronchial challenge testing, and response to medical therapy, particularly in asthma and COPD. The technique may have unique advantages in situations where spirometry and other lung function tests are not suitable, such as in infants, neuromuscular disease, sleep apnoea and critical care. Other potential applications include detection of bronchiolitis obliterans, vocal cord dysfunction and the effects of environmental exposures. However, despite great promise as a useful clinical tool, we identify a number of areas in which more evidence of clinical utility is needed before oscillometry becomes routinely used for diagnosing or monitoring respiratory disease.

How low can we go? A skeletal maturity threshold for probabilistic visual sex estimation from immature human os coxae.

OBJECTIVES: The appearance of sexually dimorphic traits varies depending on the type of bone, age, environmental and genetic factors and is closely linked to skeletal maturation sequence. Subadult sex estimation currently shows inconsistent accuracy and methods do not incorporate indicators of maturation. The goal of this study is to apply the Santos et al. (2019) adult sex estimation method on virtually reconstructed subadult os coxae and account for pelvic maturation. MATERIAL AND METHODS: The right os coxae of 194 female and male individuals aged 11-30 years from Marseille, France were virtually reconstructed from computed tomography (CT) scans. Santos et al.'s (2019) 11 traits were scored as female, male, or indeterminate. Maturation of 10 pelvic epiphyseal sites was scored using a four-stage system (0-3) to obtain a composite maturity score from 1 to 30. RESULTS: Three maturity groups were identified based on composite maturity scores ranging from 0 to 30. Individuals with a composite maturity score of 15 or higher showed 98 % sex estimation accuracy and a 6 % indeterminate rate. Scores of 2 for the ischiatic tuberosity or 1 for the anterior superior iliac spine can be used as proxies for a composite maturity score of 15 and application on incomplete bones. DISCUSSION: Sexual dimorphism was observed in the epiphyseal maturation sequence and the development of sexually dimorphic pelvic traits. The Santos et al. (2019) method is applicable on immature individuals who meet a maturation threshold with comparable accuracy to adults, without relying on known or estimated age.

Airway response to exercise by forced oscillations in asthmatic children.

Forced expiratory volume in 1 s (FEV1) detection of exercise-induced bronchoconstriction (EIB) to identify asthma has good specificity but rather low sensitivity. The aim was to test whether sensitivity may be improved by measuring respiratory resistance (Rrs) by the forced oscillation technique (FOT). Forty-seven asthmatic and 50 control children (5-12 y) were studied before and after running 6 min on a treadmill. Rrs in inspiration (Rrsi) and expiration (Rrse), FEV1 and Rrsi response to a deep inhalation (DI) were measured before and after exercise. In asthmatics versus controls, exercise induced significantly larger increases in Rrsi (p < 0.001) and larger decreases in FEV1 (p = 0.004). Asthmatics but not controls showed more bronchodilation by DI after exercise (p = 0.02). At specificity >0.90, sensitivity was 0.53 with 25% increase Rrsi and 0.45 with 27% increase Rrse or 5% decrease FEV1. It is concluded that the FOT improves sensitivity of exercise challenge, and the Rrsi response to DI may prove useful in identifying the mechanism of airway obstruction.

Within breath ventilatory responses to mechanical tracheal stimulation in anaesthetised rabbits.

Ventilatory responses to airway mechanical stimulation usually consist in mixed cough (CR) and expiration (ER) reflexes. The stimulus characteristics that would favour either reflex may vary with breathing, but the issue cannot be addressed with the usual long lasting stimulus. The aim of the study was to describe respiratory responses evoked by a punctuate tracheal stimulus and their relationship to inspiration and expiration. Experiments were repeated after bronchoconstriction. Eight anesthetized tracheotomized rabbits were stimulated in the trachea by 150 ms probing before and after methacholine inhalation (248 tests). CR and ER were evaluated from tidal volume and expiratory flow. The overall incidence of responses was larger in inspiration than expiration (p < 0.0001). A majority of responses were single CR or ER, also strongly related to breathing: 93% CR occurred with the stimulus in inspiration and 78% ER with the stimulus in expiration (p = 0.001). Bronchoconstriction did not change the incidence of single efforts, increased that of mixed responses and decreased the amplitude of preparatory and expulsive phases of CR. The study demonstrates the strong dependence of CR and ER on the phase of breathing and adds to the current evidence that regulating mechanisms clearly differ for each reflex.

Is Homo heidelbergensis a distinct species? New insight on the Mauer mandible.

The discovery of new fossils in Africa, Asia, and Europe, and the recognition of a greater diversity in the middle Pleistocene fossil record, has led to a reconsideration of the species Homo heidelbergensis. This nomen, formulated by Schoetensack in 1908 to describe the Mauer jaw (Germany), was almost forgotten during most of the past century. Numerous fossils have been attributed to it but no consensus has arisen concerning their classification. The holotype anatomical traits are still poorly understood, and numerous fossils with no mandibular remains have been placed in the taxon. Some researchers propose H. heidelbergensis as an Afro-European taxon that is ancestral to both modern humans and Neandertals whereas others think it is a strictly European species that is part of the Neandertal lineage. We focus on the validity of H. heidelbergensis, using the traditional basis of species recognition: anatomical description. We provide a comparative morphological analysis using 47 anatomical traits of 36 Pleistocene fossils from Africa, Asia, and Europe and 35 extant human mandibles. We re-examine the mandibular features of Mauer and discuss the specimen's inclusion in H. heidelbergensis, as well as alternative evolutionary theories. To lend objectivity to specimen grouping, we use multiple correspondence analysis associated with hierarchical classification that creates clusters corresponding to phenetic similarities between jaws. Our phenetic and comparative morphological analyses support the validity of H. heidelbergensis as a taxon. A set of morphological features can be statistically identified for the definition of the species. Some traits can be used to delimit H. heidelbergensis in an evolutionary framework (e.g., foramina mentale posteriorly positioned, horizontal retromolar surface). Those traits are also present on African (e.g., Tighenif) and European (e.g., Sima de los Huesos) specimens that show a close relationship with the Mauer mandible. Therefore, the definition of H. heidelbergensis is more precise and mainly supports the theory of an Afro-European taxon, which is the last common ancestor of H. neanderthalensis and H. sapiens. However, the results of this study fail to entirely discount the hypothesis that considers H. heidelbergensis as a chronospecies leading to the Neandertals.

Sub-adult aging method selection (SAMS): A decisional tool for selecting and evaluating sub-adult age estimation methods based on standardized methodological parameters.

OBJECTIVES: A decisional tool was developed to select sub-adult age estimation methods referenced in a centralized database. Through a freely accessible webpage interface, this tool allows users to evaluate how much the sampling and statistical protocols of these referenced methods comply with methodological recommendations published for building and applying methods in forensic anthropology. MATERIALS AND METHODS: 261 publications on sub-adult age estimation were collected. Three search parameters describing the anatomical element(s) and the indicators used to obtain age estimates are chosen by the user to filter the database and present the publications that best correspond to the user's selection. A simple algorithm was created to score age estimation methods according to their relevance and validity. "Relevance" and "Validity" parameters indicate how much a publication complies with user queries and published methodological recommendations, respectively; "Score" is a combination of "Relevance" and "Validity". The closer these parameters are to 1, the better the method complies with the user's choice and standardized protocols. RESULTS: The publications resulting from the user's query appear as search results alphabetically. They are characterized by their "Relevance", "Validity" and "Score" values and descriptors relating to their methodology, sampling and statistical protocols. The reference of the publications and an URL to access them online are also provided. CONCLUSIONS: SAMS is a decisional tool based on a centralized database for selecting, accessing and evaluating sub-adult age estimation methods based on published methodological recommendations. Protocol validity can be easily and fully accessed to provide the necessary information for method evaluation. The database will be gradually updated and implemented as new sub-adult age estimation methods are made available online.