Cenozoic evolution of the steppe-desert biome in Central Asia.

The origins and development of the arid and highly seasonal steppe-desert biome in Central Asia, the largest of its kind in the world, remain largely unconstrained by existing records. It is unclear how Cenozoic climatic, geological, and biological forces, acting at diverse spatial and temporal scales, shaped Central Asian ecosystems through time. Our synthesis shows that the Central Asian steppe-desert has existed since at least Eocene times but experienced no less than two regime shifts, one at the Eocene-Oligocene Transition and one in the mid-Miocene. These shifts separated three successive "stable states," each characterized by unique floral and faunal structures. Past responses to disturbance in the Asian steppe-desert imply that modern ecosystems are unlikely to recover their present structures and diversity if forced into a new regime. This is of concern for Asian steppes today, which are being modified for human use and lost to desertification at unprecedented rates.

Dental implants placed by undergraduate students: clinical outcomes and patients'/students' perceptions.

INTRODUCTION: Implant dentistry in undergraduate education is predominantly theoretical or prosthetics oriented. Clinical experience with implant surgery could provide students a better understanding of alternatives for tooth replacements. This study describes an implant dentistry programme for undergraduate students, which included surgical placement of implants. The study presents the clinical outcomes of the programme, patients' satisfaction and students' attitudes/perceptions. It reflects on barriers and problems encountered during implementation and provides suggestions for other institutions. MATERIALS AND METHODS: Thirty-six students placed one implant each for a single tooth replacement after careful radiographic assessment and pre-surgical planning. One-stage surgery was performed under one-to-one supervision. Crowns were cemented on individual abutments 3-6 months later. Crestal bone loss was assessed radiographically immediately after surgery, at crown placement and after 1 year of loading. Questionnaires were used to investigate patients' perspectives and students' opinions towards the programme, as well as their perceived level of competence. RESULTS: Thirty-six implants were placed in 27 patients; two (5.6%) failed prior to loading; mean bone loss from time of surgery to crown placement was 1.41 mm and remained unchanged thereafter, reflecting implant success. Overall, patients were satisfied and the majority would repeat the treatment by a student. The students thought it was a valuable experience, although they realised that additional education is necessary to perform implant surgery without supervision. CONCLUSION: Implant placement by undergraduate students resulted in acceptable clinical outcome parameters, patient satisfaction and positive student perceptions. These findings support the further development of clinical implant education in undergraduate dental curricula.

A population of fast radio bursts at cosmological distances.

Searches for transient astrophysical sources often reveal unexpected classes of objects that are useful physical laboratories. In a recent survey for pulsars and fast transients, we have uncovered four millisecond-duration radio transients all more than 40° from the Galactic plane. The bursts' properties indicate that they are of celestial rather than terrestrial origin. Host galaxy and intergalactic medium models suggest that they have cosmological redshifts of 0.5 to 1 and distances of up to 3 gigaparsecs. No temporally coincident x- or gamma-ray signature was identified in association with the bursts. Characterization of the source population and identification of host galaxies offers an opportunity to determine the baryonic content of the universe.

[Implementation of computerized phisician order entry in a hospital setting: what are the keys to success?]. / Implémentation de la prescription informatisée en milieu hospitalier: quelles sont les clés d'un déploiement réussi ?

INTRODUCTION: A software of computerized physician order entry [CPOE] was developed by a data-processing company in collaboration with the Mont-Godinne University Hospital By 2006, parallel to the evolution of the software, the progressive implementation of CPOE was carried out, and currently covers 16 wards, the emergency room, the recovery rooms and the center of medical care [day hospital] as well as the day surgical center OBJECTIVES: Complete computerization of the drug supply chain, including the regulation by the physician, the pharmaceutical validation, the delivery and the follow-up of stocks by pharmacy, the validation of the administration by the nurse and the tariffing of the drugs. METHOD AND RESULTS: In 2006, a working group was created in order to validate specifications allowing the development of a software of CPOE, Linked to the computerized medical record. A data-processing company was selected in order to develop this software. Two beds were computerized in the pneumology ward, in order to test and validate the software. From 2007 to 2009, 3 additional wards were computerized [geriatrics, neurosurgery, revalidation]. A steering committee of CPOE, composed of various members (direction, doctors, pharmacists, nurses, data processing specialistsl is created. This committee allows the installation of the means necessary to the deployment of CPOE in the Institution. Structured teams for the deployment are created: medical and nurse coaches. From 2009 to 2012, the deployment of the software is carried out, covering 16 wards, the emergency room, the recovery room and the day-hospitals. CONCLUSION: The computerization of the drug supply chain is a challenge which concerns the institutional level. The assets of our hospital and our project were: - a strong management committee, making of this project a priority entering the strategical planning of the institution; - a steering committee allowing each type of actor to express his needs, and of prioriser requests; - a closer medical coaching; - teams of nurses coaches, accompanying each ward, during and after the deployment; - a dynamic IT team allowing a relay between the Institution and the data-processing company. These points appeared essential and are as many keys for a successful deployment.

Dental agenesis: genetic and clinical perspectives.

Dental agenesis is the most common developmental anomaly in humans and is frequently associated with several other oral abnormalities. Whereas the incidence of missing teeth may vary considerably depending on dentition, gender, and demographic or geographic profiles, distinct patterns of agenesis have been detected in the permanent dentition. These frequently involve the last teeth of a class to develop (I2, P2, M3) suggesting a possible link with evolutionary trends. Hypodontia can either occur as an isolated condition (non-syndromic hypodontia) involving one (80% of cases), a few (less than 10%) or many teeth (less than 1%), or can be associated with a systemic condition or syndrome (syndromic hypodontia), essentially reflecting the genetically and phenotypically heterogeneity of the condition. Based on our present knowledge of genes and transcription factors that are involved in tooth development, it is assumed that different phenotypic forms are caused by different genes involving different interacting molecular pathways, providing an explanation not only for the wide variety in agenesis patterns but also for associations of dental agenesis with other oral anomalies. At present, the list of genes involved in human non-syndromic hypodontia includes not only those encoding a signaling molecule (TGFA) and transcription factors (MSX1 and PAX9) that play critical roles during early craniofacial development, but also genes coding for a protein involved in canonical Wnt signaling (AXIN2), and a transmembrane receptor of fibroblast growth factors (FGFR1). Our objective was to review the current literature on the molecular mechanisms that are responsible for selective dental agenesis in humans and to present a detailed overview of syndromes with hypodontia and their causative genes. These new perspectives and future challenges in the field of identification of possible candidate genes involved in dental agenesis are discussed.

Cranial suture biology and dental development: genetic and clinical perspectives.

Premature fusion of the calvarial bones at the sutures, or craniosynostosis (CS), is a relatively common birth defect (1:2000-3000) frequently associated with limb deformity. Patients with CS may present oral defects, such as cleft soft palate, hypodontia, hyperdontia, and delayed tooth eruption, but also unusual associations of major dental anomalies such as taurodontism, microdontia, multiple dens invaginatus, and dentin dysplasia. The list of genes that are involved in CS includes those coding for the different fibroblast growth factor receptors and a ligand of ephrin receptors, but also genes encoding transcription factors, such as MSX2 and TWIST. Most of these genes are equally involved in odontogenesis, providing a pausible explanation for clinical associations of CS with dental agenesis or tooth malformations. On the basis of the present knowledge on genes and transcription factors that are involved in craniofacial morphogenesis, and from dental clinics of CS syndromes, the molecular mechanisms that control suture formation and suture closure are expected to play key roles in patterning events and development of teeth. The purpose of this article is to review and merge the recent advances in the field of suture research at the genetic and cellular levels with those of tooth development, and to apply them to the dental clinics of CS syndromes. These new perspectives and future challenges in the field of both dental clinics and molecular genetics, more in particular the identification of possible candidate genes involved in both CS and dental defects, are discussed.

Abnormal dentin structure in two novel gene mutations [COL1A1, Arg134Cys] and [ADAMTS2, Trp795-to-ter] causing rare type I collagen disorders.

Histological and ultrastructural observations of dentin of two patients affected with rare types of type I collagen disorders are presented. In the first case, a homozygous nonsense mutation in ADAMTS2 (substitution of a codon for tryptophan by a stopcodon) causes type VIIC Ehlers-Danlos syndrome (EDS) with multiple tooth agenesis and focal dysplastic dentin defects. In the second case, a missense mutation in COL1A1 (substitution of arginine by cysteine) results in a type I EDS phenotype with clinically normal-appearing dentition. Tooth samples are investigated by using light microscopy (LM), transmission electron microscopy (TEM) and immunostaining for types I and III collagen, and tenascin. These are compared with samples from patients with types III and IV osteogenesis imperfecta (OI) in association with dentinogenesis imperfecta (DI), showing a consistently abnormal appearance of the dentin in all specimens, with variations being primarily those of degree of change. Similarities in histological changes include the alternating presence of normal and severe pathological areas in primary and secondary dentin, the latter being characterized by large canal-like structures in atubular areas. Ultrastructural evidence of pathological dentinogenesis include abnormal distribution, size and organization of collagen fibers, which may also be found in clinically unaffected teeth. The histological and ultrastructural changes seen can be explained on the basis of odontoblast dysfunction which may be secondary to the collagen defect, interfering with different levels of odontoblast cell function and intercellular communication. These observations on (ultra)structural dentin defects associated with the two novel gene mutations are the first ever reported.

Seckel syndrome associated with oligodontia, microdontia, enamel hypoplasia, delayed eruption, and dentin dysmineralization: a new variant?

Seckel syndrome (SCKL) [OMIM Entry 210600] is a rare, autosomal recessive syndrome, characterized by severe intrauterine and postnatal growth retardation, microcephaly, mental retardation, and typical facial appearance with beaklike protrusion of the midface (bird-headed). Associated findings may include limb anomalies, dislocation of femoral heads, scoliosis, and gastrointestinal malformation. A 14-year-old boy is presented with brain hypoplasia, pachygyria, hydrocephaly, enamel hypoplasia and root dysplasia in the temporary dentition, and oligodontia, severe microdontia, and delayed eruption of the permanent dentition. The association of SCKL with the above unusual dental findings may represent a new phenotype.

Dentinogenesis imperfecta associated with short stature, hearing loss and mental retardation: a new syndrome with autosomal recessive inheritance?

The follow-up history and oral findings in two brothers from consanguineous parents suggest that the association of dentinogenesis imperfecta (DI), delayed tooth eruption, mild mental retardation, proportionate short stature, sensorineural hearing loss and dysmorphic facies may represent a new syndrome with autosomal recessive inheritance. Histological examination of the dentin matrix of a permanent molar from one of the siblings reveals morphological similarities with defective dentinogenesis as presenting in patients affected with Osteogenesis Imperfecta (OI), a condition caused by deficiency of type I collagen. A number of radiographic and histological characteristics, however, are inconsistent with classical features of DI. These findings suggest that DI may imply greater genetical heterogeneity than currently assumed.

Unusual oral findings in dermatosparaxis (Ehlers-Danlos syndrome type VIIC).

A 13-year-old patient with dermatosparaxis (Ehlers-Danlos syndrome type VIIC), an autosomal recessive disorder of procollagen-I-N-proteinase, is presented. The oral findings comprise micrognathia, hypodontia, localized microdontia, opalescent tooth discoloration, root dysplasia, pulp obliteration, severe gingival hyperplasia, frontal open bite, and severe restriction of TMJ mobility. The reported anomalies suggest the need for expanding the present phenotypic spectrum. This is the first report on oral findings in the syndrome.

Is a lung perfusion scan obtained by using single photon emission computed tomography able to improve the radionuclide diagnosis of pulmonary embolism?

Planar pulmonary scintigraphy is still regularly performed for the evaluation of pulmonary embolism (PE). However, only about 50-80% of cases can be resolved by this approach. This study evaluates the ability of tomographic acquisition (single photon emission computed tomography, SPECT) of the perfusion scan to improve the radionuclide diagnosis of PE. One hundred and fourteen consecutive patients with a suspicion of PE underwent planar and SPECT lung perfusion scans as well as planar ventilation scans. The final diagnosis was obtained by using an algorithm, including D-dimer measurement, leg ultrasonography, a V/Q scan and chest spiral computed tomography, as well as the patient outcome. A planar perfusion scan was considered positive for PE in the presence of one or more wedge shaped defect, while SPECT was considered positive with one or more wedge shaped defect with sharp borders, three-plane visualization, whatever the photopenia. A definite diagnosis was achieved in 70 patients. After exclusion of four 'non-diagnostic' SPECT images, the prevalence of PE was 23% (n =15). Intraobserver and interobserver reproducibilities were 91%/94% and 79%/88% for planar/SPECT images, respectively. The sensitivities for PE diagnosis were similar for planar and SPECT perfusion scans (80%), whereas SPECT had a higher specificity (96% vs 78%; P =0.01). SPECT correctly classified 8/9 intermediate and 31/32 low probability V/Q scans as negative. It is concluded that lung perfusion SPECT is readily performed and reproducible. A negative study eliminates the need for a combined V/Q study and most of the 'non-diagnostic' V/Q probabilities can be solved with a perfusion image obtained by using tomography.

Oral manifestations of patients with Marfan syndrome: a case-control study.

OBJECTIVE: The purpose of this study was to conduct a complete analysis of the oral abnormalities of patients with Marfan syndrome. STUDY DESIGN: Twenty three patients with Marfan syndrome and 69 healthy controls were studied. The subjects were screened for cariologic and periodontal alterations, as well as structural defects of enamel and dentin. Data analysis was performed by using the t test, the chi-square test, and regression models. RESULTS: Patients aged 0 to 17 years were significantly at risk for caries. Local hypoplastic enamel spots were more frequent in Marfan syndrome and could be related to caries history of the deciduous dentition. Root deformity, abnormal pulp shape, and pulpal inclusions were a frequent finding in patients with Marfan syndrome. Calculus and gingival indices were significantly higher in the study group as well. CONCLUSIONS: This study shows the importance of early diagnosis of oral anomalies and timely treatment of dental problems in Marfan syndrome. A series of therapeutic guidelines to be integrated in treatment strategies is proposed.

Mechanisms of acute eosinophilic inflammation in a case of acute eosinophilic pneumonia in a 14-year-old girl.

BACKGROUND: Acute eosinophilic pneumonia (AEP) is characterized by respiratory distress, eosinophilic infiltration in the lung, acute onset, resolution of symptoms with corticosteroids and the absence of relapse. Studies to identify the pathophysiology of AEP in adults have demonstrated eosinophil activation in the BAL fluid, and the presence of high levels of interleukin 5 (IL-5) in the BAL. OBJECTIVE: To investigate the pathophysiology of AEP with pleural effusion in a paediatric patient. METHODS: ECP levels in the BALand pleural fluid was determined by radioimmunoassay. IL-5 and GM-CSF concentrations in the BAL and pleural fluid were measured by Elisa. Immunohistochemistry studies performed on open lung biopsy included a specific ICAM-1 immunostaining and a ECP specific immunostaining (EG2+). RESULTS: High levels of ECP were found in the BAL (5 microg/L) and pleural fluid (750 microg/L) demonstrating eosinophil activation at these sites. Immunohistochemistry illustrated activated (EG2+) eosinophils in the interalveolar septa and alveolar space and detected increased expression of ICAM-1 on alveolar epithelial cells. High levels of IL-5 were measured in the BAL (1334 pg/mL) and pleural fluid (7014 pg/mL), while elevated concentrations of GM-CSF (150 pg/mL) were found in the BAL. CONCLUSION: We conclude that in this paediatric patient with AEP activated eosinophils were present in the BAL fluid, in the interalveolar septa and in the pleural space while increased ICAM-1 expression was detected on alveolar epithelial cells, contributing, at least partly, for their adhesive interactions. IL-5 and GM-CSF are likely important to the massive eosinophil recruitment and activation in the lung, while IL-5 is probably related to eosinophil accumulation and activation in the pleural space. Thus, lung generation of eosinophil-active cytokines is central to the pathophysiology of AEP in paediatric patients.

Persisting perfusion defect in transient ischemic attacks: a new clinically useful subgroup?

BACKGROUND AND PURPOSE: Cerebral infarction and prolonged regional hypoperfusion have been described in patients with transient ischemic attacks (TIAs). The aim of this study was to compare the sensitivity of single-photon emission CT (SPECT) with that of brain CT and to evaluate the clinical significance of differentiation of TIA patients with or without focal hypoperfusion. METHODS: From a hospital-based population, we studied the SPECT and CT findings in 76 consecutive patients, without a stroke history, who presented with TIA in the carotid artery territory. The recorded variables were the time of SPECT, imaging (<36 or > or = 36 hours), clinical presentation, history of previous TIA(s), duration of the presenting attack (<2 or > or = 2 hours), vascular risk factors, and etiology. We used both visual and semiquantitative analyses for the SPECT evaluation. Acetazolamide challenge was not performed. RESULTS: The overall SPECT sensitivity was 36% (27/76). When brain CT and SPECT were performed in the same patients, the SPECT sensitivity was significantly higher than that of CT (19/59 [32%] versus 8/59 [14%]; P=.007). The SPECT sensitivity was not dependent on the time of investigation, duration of attacks, history of TIA(s), or the clinical presentation. The vascular risk and etiologic factors were not significantly different between the patients with or without prolonged focal hypoperfusion. Logistic regression did not identify any variable to discriminate the two groups. CONCLUSIONS: Despite its better sensitivity compared with CT, SPECT performed without the acetazolamide test provides no additional clinically useful information on the vascular risk factors and etiology in TIA patients.

Cerebral blood flow and perfusion reserve capacity in hemodynamic carotid transient ischemic attacks due to innominate artery stenosis.

Ischemia in the carotid artery territory due to atherosclerotic stenosis of the innominate artery is rare. We report a case in which transcranial Doppler ultrasonography (TCD) and SPECT with acetazolamide challenge proved the hemodynamic mechanism. The patient presented with three hypotensive TIAs in the right middle cerebral artery territory. Angiography showed a tight innominate artery stenosis and subclavian steal but no coexistent carotid or vertebrobasilar lesion. SPECT showed disturbed regional blood flow in the middle cerebral artery territory along with an exhausted perfusion reserve capacity. After angioplasty, flow velocities were normal and the perfusion reserve was restored. SPECT should be used to select patients at risk susceptible to benefit from angioplasty.

HMPAO single-photon emission computed tomography in posterior circulation infarcts.

The sensitivity of single-photon emission computed tomography (SPECT) in evaluating posterior circulation infarcts compared with that of computed tomography (CT) or magnetic resonance imaging (MRI) remains unknown. In a hospital-based population, the authors studied SPECT, CT, and MRI in 35 consecutive patients presenting with acute infarction clinically localized in the thalamus (7), posterior cerebral artery (PCA) territory (15), brainstem (19), and cerebellum (3). Multiple infarcts were noted in 8 patients. Overall, the SPECT sensitivity was lower than that of MRI (21% vs 93%, p = 0.004) and CT (42% vs 65%, p = 0.046). The SPECT and CT sensitivities were not significantly different (67% vs 73%) for PCA infarcts. Performed within 24 hours, SPECT showed a relevant hypoperfusion in all PCA infarcts. For brainstem infarcts, CT (33%, p = 0.074) and MRI (91%, p = 0.004) were more sensitive than SPECT, which showed no hemispheric hypoperfusion. The sensitivity of the three imaging techniques was 100% for large cerebellar infarcts. For the small group of thalamic infarcts, the SPECT, CT, and MRI sensitivities were 14, 71, and 100%, respectively. Thus, SPECT compared to CT and MRI is not helpful in the subacute phase to localize PCA and cerebellar infarcts and is of limited value for thalamic infarcts. In the first hours, the absence of cerebral hypoperfusion in brainstem infarcts may help to differentiate them from hemispheric infarcts usually associated with profound hypoperfusion.

Comparative correlations of HMPAO SPECT indices, neurological score, and stroke subtypes with clinical outcome in acute carotid infarcts.

BACKGROUND AND PURPOSE: The prognostic value of single-photon emission computed tomography (SPECT) remains controversial. The aim of this study was to compare the prognostic value of stroke severity, stroke subtypes, and SPECT indices and to determine which predictive factors have an independent effect on clinical outcome. METHODS: We studied 55 consecutive patients with acute (< 12 hours) carotid infarct within 36 hours of symptom onset with SPECT. Clinical presentation was assessed by the Canadian Neurological Scale and stroke subtypes. SPECT indices were the degree and size of hypoperfusion and crossed cerebellar diaschisis as assessed by a semiquantitative analysis. Outcome was evaluated by the functional status and mortality (Rankin Scale score at 1 month). RESULTS: The Rankin Scale score correlated with the degree (r = .580; P < .00001) and size (r = .616; P < .00001) of hypoperfusion. The mean degree and size of hypoperfusion were significantly higher in patients with poor outcome. Crossed cerebellar diaschisis had no significant predictive value. Statistical analysis determined threshold values for the Canadian Neurological Scale score and the degree and size of hypoperfusion for the functional status and mortality. The degree and size of hypoperfusion had no higher performance than the Canadian Neurological Scale score. The negative predictive value was excellent for both clinical and SPECT indices. Multivariate analysis selected only the size of hypoperfusion as an independent predictor for the functional status (P = .004) and the Canadian Neurological Scale score for mortality (P = .009). CONCLUSIONS: SPECT performed within 36 hours of onset predicts clinical outcome, but different clinical and SPECT indices with threshold values should be chosen according to the relevant outcome end point.

Exercise gated planar myocardial perfusion imaging using technetium-99m sestamibi for the diagnosis of coronary artery disease: an alternative to exercise tomographic imaging.

Single-photon emission tomography (SPET) using technetium-99m labelled myocardial tracers (e.g. 99mTc-sestamibi) has become one of the most popular myocardial imaging methods for the diagnosis of coronary artery disease (CAD). This prospective study was designed to evaluate the diagnostic performance of 99mTc-sestamibi exercise gated planar myocardial imaging by comparison with both visual and quantitative analyses of SPET. The study was conducted in 115 consecutive patients with known or suspected CAD, including 54 patients with a previous myocardial infarction (MI), referred for exercise testing prior to coronary angiography. Multi-gated planar imaging and SPET were performed after bicycle exercise. The end-diastolic (ED) and SPET images were visually scored (SVi). Myocardial uptake was quantitated on SPET slices using maximum count circumferential profiles (SQu) and defect extent was measured by comparison with gender-matched data sets obtained from 27 controls (< 5% likelihood of CAD). CAD was defined as coronary artery stenosis > 50% and/or regional wall motion abnormality. The cut-off criteria for positivity of the three procedures were determined from receiver operating characteristic (ROC) curves derived from the data of patients without previous MI. The area under the ROC curves was similar for ED, SVi and SQu. This was confirmed by the analysis of sensitivity performed using the ROC curve-derived cut-off criteria, in patients with or without previous MI. SVi was more sensitive than ED in identifying the diseased vessel(s) (ED: 41% vs SVi: 80%; P < 0.0005) but ED was more specific in this respect (ED: 79% vs SVi: 61%; P < 0.0005).(ABSTRACT TRUNCATED AT 250 WORDS)

[Status of 3 years of hyperthyroidism treatment with iodine 131]. / Bilan de trois années de traitement d'hyperthyroïdies par iode-131.

We analysed retrospectively the results obtained during 3 years in the treatment of thyrotoxicosis with 131-iodine. A group of 32 patients, including 21 Graves' diseases, 10 multinodular toxic goitres and 1 toxic adenoma has been collected. The therapeutic efficacy of one dose of radioiodine, assessed after 6 months was 100% in toxic multinodular goitres and 57% in Graves' diseases. No acute complications were observed. The best radiosensitivity of toxic multinodular goitres compared with diffuse goitres is probably due to the mechanisms themselves of thyrotoxicosis in these diseases. Results also suggest that multinodular toxic goitres in our country should be systematically treated with antithyroid drugs before radioiodine. In Graves' disease, no predictive factor of the early response to therapy could be definitely evidenced. Finally, clinicians should be aware of the advantages of such a treatment of thyrotoxicosis which is not very aggressive and at least definitive.