Poor blood pressure control in general practice: In search of explanations

SummaryBackgroundArterial hypertension is managed mainly by general practitioners. The blood pressure level of most patients treated in a general practice setting is greater than or equal to 140/90mmHg.AimsTo understand why a blood pressure level greater than or equal to 140/90mmHg does not lead to a change of treatment.MethodsOver a 2-week period, 479 hypertensive patients were included in a cross-sectional study by 27 general practitioners. Consultation data were collected, as were reasons why patients with a blood pressure level greater than or equal to 140/90mmHg did not have their treatment changed.ResultsBlood pressure level was greater than or equal to 140/90mmHg in 58% of patients; treatment was changed in 15% of these individuals. The lack of change in treatment was justified by the physicians as follows: the blood pressure measurements were not considered to be representative (about 30% of cases); the therapeutic result was considered to be satisfactory in the circumstances (about 30% of cases); change was not appropriate given the patient's specific context (the remaining third of cases). The proportion of uncontrolled hypertensive patients whose treatment remained the same was significantly higher among patients with a disease that affected their lifestyle or threatened their life expectancy.ConclusionThe disappointing therapeutic results observed in the management of arterial hypertension do not arise only from poor application of guidelines by general practitioners. Reluctance to rely on blood pressure measurements, a perception that guidelines are revised frequently and are not always clear, and consideration of the general practitioner's activity in the patient's specific context are the main factors involved

Frontal sinus variation in large samples of extant species of the genera Pan, Gorilla and Homo

Frontal pneumatisation is not present in all primates, and among extant species, ethmoidally-derived frontal sinuses are present only in the genera Pan, Gorilla and Homo. A simple and repeatable method is described here to quantify variation in the shape, size and bilateral variation of the frontal sinuses. This has allowed the first large study of these variables, including analyses of large samples of P. paniscus, P. troglodytes, G. gorilla and of several geographically diverse populations of H. sapiens. Frontal sinus shape and size are potential phylogenetic markers in primate systematics. We suggest that, in contrast to an allometric relationship between endocranial and frontal sinus form in Pan and Gorilla, H. sapiens is autapomorphic in having highly variable, supero-inferiorly large frontal sinuses, whose size is unrestricted by variation in cranial form. However, we also describe differences in frontal pneumatisation between those taxa. H. sapiens differs from the other taxa in having relatively smaller frontal sinuses that are more variable in shape and size. In P. troglodytes, P. paniscus and G. gorilla, the shape and size of frontal pneumatisation correlates positively with the overall size of the braincase. This suggests that the large space available in the bone structures of the non-human primates analysed allows the sinuses to develop under only slight constraint (if any) from surrounding structures. In H. sapiens, a significant correlation is observed between the asymmetry in the anterior extension of the frontal lobes of the brain and the shape and extension of the frontal sinuses. We suggest that the more vertical orientation of the H. sapiens frontal bone, its reduced thickness, the reduction of the supraorbital tori and the increased influence of the frontal lobes appear to have modified the integration between the skull, brain and sinuses in the frontal region in our species compared to our nearest extant relatives. Our results reduce the possibility of a strong functional origin for the variation in size and shape of the frontal sinuses in the primates analysed

The internal cranial anatomy of the Middle Pleistocene Broken Hill 1 cranium

The cranium (Broken Hill 1 or BH1) from the site previously known as Broken Hill, Northern Rhodesia (now Kabwe, Zambia) is one of the best preserved hominin fossils from the mid-Pleistocene. Its distinctive combination of anatomical features, however, makes its taxonomic attribution ambiguous. High resolution microCT, which has not previously been employed for gross morphological studies of this important specimen, allows a precise description of the internal anatomical features of BH1, including the distribution of cranial vault thickness and its 2 internal composition, paranasal pneumatisation, pneumatisation of the temporal bone and endocranial anatomy. Relative to other chronologically and taxonomically relevant specimens, BH1 shows unusually marked paranasal pneumatisation and a fairly thick cranial vault. For many of the features analysed, this fossil does not exhibit the apomorphic conditions observed in either Neandertals or Homo sapiens. Its morphology and the general shape of the brain and of the skull may be partly explained by an allometric relationship relative to the features observed in Homo erectus s.l. However, further research is still necessary to better appreciate the cranial anatomy of BH1 and the role of Homo rhodesiensis/Homo heidelbergensis in the course of human evolution. This paper also deals with more general aspects of scientific practices in palaeoanthropology. In particular, we give precise descriptions of many internal anatomical features of Broken Hill 1, a specimen discovered in 1921. This important and unique dataset will allow independent comparative studies in the future. However, we were limited in our study by the very restricted amount of comparative information available for Homo fossils. In our view, scientific papers dealing with the anatomical description of hominin specimens, both in the case of announcements of new discoveries and of discussions of important specimens found decades ago, should always include qualitative and quantitative data that truly allow for further independent research.CBS and LTB thank the Calleva Foundation and the Human Origins Research Fund for funding

What do brain endocasts tell us? A comparative analysis of the accuracy of sulcal identification by experts and perspectives in palaeoanthropology

Palaeoneurology is a complex field as the object of study, the brain, does not fossilize. Studies rely therefore on the (brain) endocranial cast (often named endocast), the only available and reliable proxy for brain shape, size and details of surface. However, researchers debate whether or not specific marks found on endocasts correspond reliably to particular sulci and/or gyri of the brain that were imprinted in the braincase. The aim of this study is to measure the accuracy of sulcal identification through an experiment that reproduces the conditions that palaeoneurologists face when working with hominin endocasts. We asked 14 experts to manually identify well-known foldings in a proxy endocast that was obtained from an MRI of an actual in vivo Homo sapiens head. We observe clear differences in the results when comparing the non-corrected labels (the original labels proposed by each expert) with the corrected labels. This result illustrates that trying to reconstruct a sulcus following the very general known shape/position in the literature or from a mean specimen may induce a bias when looking at an endocast and trying to follow the marks observed there. We also observe that the identification of sulci appears to be better in the lower part of the endocast compared to the upper part. The results concerning specific anatomical traits have implications for highly debated topics in palaeoanthropology. Endocranial description of fossil specimens should in the future consider the variation in position and shape of sulci in addition to using models of mean brain shape. Moreover, it is clear from this study that researchers can perceive sulcal imprints with reasonably high accuracy, but their correct identification and labelling remains a challenge, particularly when dealing with extinct species for which we lack direct knowledge of the brain

Frontal sinuses and human evolution

The frontal sinuses are cavities inside the frontal bone located at the junction between the face and the cranial vault and close to the brain. Despite a long history of study, understanding of their origin and variation through evolution is limited. This work compares most hominin species? holotypes and other key individuals with extant hominids. It provides a unique and valuable perspective of the variation in sinuses position, shape, and dimensions based on a simple and reproducible methodology. We also observed a covariation between the size and shape of the sinuses and the underlying frontal lobes in hominin species from at least the appearance of Homo erectus. Our results additionally undermine hypotheses stating that hominin frontal sinuses were directly affected by biomechanical constraints resulting from either chewing or adaptation to climate. Last, we demonstrate their substantial potential for discussions of the evolutionary relationships between hominin species. Variation in frontal sinus shape and dimensions has high potential for phylogenetic discussion when studying human evolution

Frontal sinuses and human evolution

The frontal sinuses are cavities inside the frontal bone located at the junction between the face and the cranial vault and close to the brain. Despite a long history of study, understanding of their origin and variation through evolution is limited. This work compares most hominin species’ holotypes and other key individuals with extant hominids. It provides a unique and valuable perspective of the variation in sinuses position, shape, and dimensions based on a simple and reproducible methodology. We also observed a covariation between the size and shape of the sinuses and the underlying frontal lobes in hominin species from at least the appearance of Homo erectus. Our results additionally undermine hypotheses stating that hominin frontal sinuses were directly affected by biomechanical constraints resulting from either chewing or adaptation to climate. Last, we demonstrate their substantial potential for discussions of the evolutionary relationships between hominin species

Frontal sinuses and human evolution.

The frontal sinuses are cavities inside the frontal bone located at the junction between the face and the cranial vault and close to the brain. Despite a long history of study, understanding of their origin and variation through evolution is limited. This work compares most hominin species' holotypes and other key individuals with extant hominids. It provides a unique and valuable perspective of the variation in sinuses position, shape, and dimensions based on a simple and reproducible methodology. We also observed a covariation between the size and shape of the sinuses and the underlying frontal lobes in hominin species from at least the appearance of 'Homo erectus'. Our results additionally undermine hypotheses stating that hominin frontal sinuses were directly affected by biomechanical constraints resulting from either chewing or adaptation to climate. Last, we demonstrate their substantial potential for discussions of the evolutionary relationships between hominin species

Frontal sinuses and human evolution

The frontal sinuses are cavities inside the frontal bone located at the junction between the face and the cranial vault and close to the brain. Despite a long history of study, understanding of their origin and variation through evolution is limited. This work compares most hominin species’ holotypes and other key individuals with extant hominids. It provides a unique and valuable perspective of the variation in sinuses position, shape, and dimensions based on a simple and reproducible methodology. We also observed a covariation between the size and shape of the sinuses and the underlying frontal lobes in hominin species from at least the appearance of Homo erectus. Our results additionally undermine hypotheses stating that hominin frontal sinuses were directly affected by biomechanical constraints resulting from either chewing or adaptation to climate. Last, we demonstrate their substantial potential for discussions of the evolutionary relationships between hominin species

Morphological co-variation of the cranium and endocast in the genus Homo

Il existe chez les espèces du genre Homo une diversité morphologique crânienne et cérébrale importante, et les interactions de ces deux éléments sont complexes. De manière générale, au cours de l’évolution de ce taxon, le neurocrâne prend une importance croissante par rapport au bloc facial en raison d’une expansion cérébrale marquée. Cependant, les modalités de cette expansion sont multiples, et elle se met en place chez les différentes espèces via des modifications morphologiques qui leur sont propres. Mise à part l’augmentation du volume cérébral, l’endocrâne témoigne de réorganisations neuroanatomiques. Ces différents facteurs - volume et organisation – ainsi que les contraintes morpho-fonctionnelles diverses exercées sur la face externe du crâne, sont susceptibles de résulter en une variété de relations morphologiques et spatiales entre le neurocrâne et l’endocrâne. Il est donc pertinent de documenter ces relations afin de pouvoir par la suite mieux appréhender la variabilité et les mécanismes évolutifs à l’oeuvre chez les différents taxons du genre Homo. Nous explorons dans ce travail de thèse les variations jointes du neurocrâne et de l’endocrâne dans le genre Homo et chez Homo sapiens. Cette contribution est basée sur l’analyse de modèles virtuels de crânes et d’endocrânes à l’aide de méthodes géométriques et d’une méthode innovative de déformations de surfaces. Nous avons étudié des données morphologiques issues de populations actuelles afin d’éclaircir la nature des relations entre le neurocrâne et l’endocrâne chez Homo sapiens. Pour cela, nous avons comparé les asymétries des hémisphères de l’endocrâne – qui reflètent celles des hémisphères cérébraux – aux asymétries de la voûte crânienne. Les schémas d’asymétrie bilatérale relevés sont identiques sur le crâne et sur l’endocrâne. Cela s’explique par une morphologie de la voûte du crâne calquée sur celle de l’endocrâne, malgré un effet « tampon » de l’os qui n’enregistre pas sur sa face externe toutes les asymétries cérébrales. Les possibles corrélations entre le degré d’asymétrie et des facteurs tels que la conformation générale du crâne, la robustesse des superstructures osseuses, le sexe et le volume endocrânien ont également été explorées. Nous avons ensuite analysé les schémas de co-variation entre neurocrâne et endocrâne au sein du genre Homo. Nous avons ainsi pu mettre en évidence des éléments de co-variation qui concernent l’ensemble du genre Homo, et d’autres qui sont spécifiques à certains taxons, notamment aux Néandertaliens ou à Homo sapiens. Ainsi, si la conformation de la voûte crânienne est très semblable à la morphologie endocrânienne, les interactions crâne-endocrâne dans la zone occipitale et cérébelleuse apparaissent plus variables, et semblent inféodées au degré de globularisation de l’ensemble du cerveau et du neurocrâne. Ces résultats mettent en évidence certaines interactions entre réorganisations cérébrales et morphologie crânienne chez les différentes espèces du genre Homo, et soulignent le caractère crucial du croisement des données et des méthodes pour l’interprétation du registre fossile.Species of the genus Homo display cranial and endocranial morphological variations, with complex interactions between these two elements. Generally speaking, throughout the evolution of this taxon the neurocranium becomes increasingly important by comparison with the facial skeleton, due to a marked cerebral expansion. The modalities of this expansion differ accross species and occur at least partly through species-specific morphological processes. Apart from the increase in cerebral volume, the endocast bears the traces of neuroanatomical reorganisations. These two factors – volume and organisation – as well as various morpho-functional constraints on the external face of the cranium, may result in a variety of morphological and spacial relationships between the neurocranium and the endocranium. It is therefore important to document these relations in order to better apprehend the variability and the evolutionary mechanisms behind the morphologies of the different Homo species.This doctoral thesis explores the joint morphological variations of the neurocranium and endocast in the genus Homo and within Homo sapiens through multiple approaches. We offer a contribution to this topic based on shape analyses of virtual crania and endocasts, using geometric morphometrics and an innovative technique of surface deformations. We analysed morphological data from extant populations in order to clarify the nature of the relationship between the neurocranium and the endocast in Homo sapiens. One of the lines of evidence investigated is the correspondence between neurocranial and endocranial (and therefore cerebral) gross asymmetries. Our results show that the patterns of bilateral asymmetries of the neurocranium are identical to those of the endocranium. There is a close correspondance between the morphologies of the endocranial and cranial vaults, despite the neurocranium not displaying the full extent of cerebral asymmetries on its external vault. Correlations between asymmetry and factors including sex, endocranial volume and importance of the bony superstructures were also tested. Co-variation patterns between neurocranial and endocranial morphologies in the genus Homo were analysed. Our results highlight elements of co-variation between the neuro and endocranium which are shared accross the genus Homo, and others which are species-specific. While the cranial vault closely follows endocranial morphology, interaction patterns between the endo and neurocranium in the occipito-cerebellar area appear more variable and linked to the overall degree of globularisation of the brain and neurocranium. These results highlight some of the interactions between cerebral reorganisations and cranial morphology in Homo species, and underline the importance of crossing data and methods in order to interpret the fossil record