Environmental drivers of increased ecosystem respiration in a warming tundra.

Arctic and alpine tundra ecosystems are large reservoirs of organic carbon1,2. Climate warming may stimulate ecosystem respiration and release carbon into the atmosphere3,4. The magnitude and persistency of this stimulation and the environmental mechanisms that drive its variation remain uncertain5-7. This hampers the accuracy of global land carbon-climate feedback projections7,8. Here we synthesize 136 datasets from 56 open-top chamber in situ warming experiments located at 28 arctic and alpine tundra sites which have been running for less than 1 year up to 25 years. We show that a mean rise of 1.4 °C [confidence interval (CI) 0.9-2.0 °C] in air and 0.4 °C [CI 0.2-0.7 °C] in soil temperature results in an increase in growing season ecosystem respiration by 30% [CI 22-38%] (n = 136). Our findings indicate that the stimulation of ecosystem respiration was due to increases in both plant-related and microbial respiration (n = 9) and continued for at least 25 years (n = 136). The magnitude of the warming effects on respiration was driven by variation in warming-induced changes in local soil conditions, that is, changes in total nitrogen concentration and pH and by context-dependent spatial variation in these conditions, in particular total nitrogen concentration and the carbon:nitrogen ratio. Tundra sites with stronger nitrogen limitations and sites in which warming had stimulated plant and microbial nutrient turnover seemed particularly sensitive in their respiration response to warming. The results highlight the importance of local soil conditions and warming-induced changes therein for future climatic impacts on respiration.

Thawing Yedoma permafrost is a neglected nitrous oxide source.

In contrast to the well-recognized permafrost carbon (C) feedback to climate change, the fate of permafrost nitrogen (N) after thaw is poorly understood. According to mounting evidence, part of the N liberated from permafrost may be released to the atmosphere as the strong greenhouse gas (GHG) nitrous oxide (N2O). Here, we report post-thaw N2O release from late Pleistocene permafrost deposits called Yedoma, which store a substantial part of permafrost C and N and are highly vulnerable to thaw. While freshly thawed, unvegetated Yedoma in disturbed areas emit little N2O, emissions increase within few years after stabilization, drying and revegetation with grasses to high rates (548 (133-6286) µg N m-2 day-1; median with (range)), exceeding by 1-2 orders of magnitude the typical rates from permafrost-affected soils. Using targeted metagenomics of key N cycling genes, we link the increase in in situ N2O emissions with structural changes of the microbial community responsible for N cycling. Our results highlight the importance of extra N availability from thawing Yedoma permafrost, causing a positive climate feedback from the Arctic in the form of N2O emissions.

Agenesis of the internal carotid artery: a family pathology?

The internal carotid artery agenesis is a rare malformation disorder. We report the case of a 12-year-old boy suffering migraine, who had presented an episode featuring amaurosis fugax, spontaneously regressed. CT angiography images show hypoplasia of the left common carotid artery with loss of opacification of the left internal carotid artery consistent to agenesis. Moreover CT scans through the skull base demonstrate absence of left petrous carotid canal and an hypertrophic left middle cerebral artery originating from an aberrant artery arising from the right cavernous carotid. All diagnostic examinations confirmed the presence of the internal carotid artery agenesis, as Lie's type IV. We started an annual follow up that over the next 7 years did not reveal any change in magnetic resonance angiography images.

Chiari type 1 malformation in Neurofibromatosis type 1: experience of a center and review of the literature.

OBJECTIVE: To evaluate the possible correlation and the true incidence between Neurofibromatosis type 1 and Arnold-Chiari malformation type I. MATERIALS AND METHODS: We reviewed all clinical charts, neurological consultations and MRI scans of 428 NF1 patients followed by 1994 to 2014 in our Department. NF1 patients in our clinic are seen usually every year by both the dermatologist and the neurologist. All patients also undergo a brain and spinal cord with the same 1.5 Tesla MRI scan. RESULTS: We found a diagnosis of Arnold Chiari malformation type I in 9 of the 428 NF1 cases (2%). CONCLUSION: This frequency is higher than that expected on the basis of a chance association. Therefore we underline the importance of serial MRI studies in patients with NF1 to assess the presence of cranio-cervical anomalies. Future studies should try to better understand what are the pathogenetic mechanisms underlying this close association.

[Liver capillariasis (Calodium hepaticum) in rodents from Ituri (DRC) and Dakar (Senegal)]. / Capillariose hépatique (Calodium hepaticum) chez des rongeurs en Ituri (République démocratique du Congo) et à Dakar (Sénégal).

Human hepatic capillariosis due to Calodium hepaticum is rarely described in Africa, probably because of the lack of diagnosis tools. However, it is known that the animal reservoir is made up of rodents. During a study performed on 24 black rats (Rattus rattus) trapped in Rethy (CongoDR) and 20 Gambian pouched rats (Cricetomys gambianus) in Dakar (Senegal), macroscopic and histological hepatic lesions of capillariosis were found in 8 of these rodents (3 in Rethy and 5 in Dakar). These results led us to propose, besides hygiene measures, an epidemiologic survey of this serious parasitosis, particularly in children, in the course of serological and/or coproscopic investigations.

Accuracy of transcranial ultrasound in the detection of mild white matter lesions in newborns.

Cranial Ultrasound (cUS) may not be sensitive enough to detect subtle white matter (WM) injuries. Our study compared serial cUS with MRI at term equivalent age (TEA) to determine if it is possible to identify an ultrasound representation of subtle diffuse WM injuries such as punctate lesions (PWMLs) and diffuse excessive high signal intensity (DEHSI). Fifty-six very preterm infants were scanned sequentially from birth to TEA, an MRI was performed at TEA. Each echodensity found on cUS was classified as absent, transient (≤7 days), or prolonged (>7 days). A transient periventricular echodensity was detected in seven infants (12.5%), and a prolonged echodensity in 15 (26.8%). MRI examinations were performed in all 56 infants. No altered signal intensity was found in 18 infants (32.1%). DEHSI was detected in 14 infants (25%), and PWMLs were detected in eight babies (14.3%). Both abnormalities were found in 16 infants (28.6%). The positive predictive values of the prolonged echodensity for DEHSI and PWMLs were 86.7% and 46.7% respectively. However, a significant statistical correspondence (p=0.002, Odds Ratio 11.9) was found comparing DEHSI with cUS abnormal echodensities. Serial cUS during the neonatal period in preterm infants is essential and cannot be replaced with MRI at TEA. MRI seems to be more reliable in detecting mild or moderate WM abnormalities. However, serial cUS performed by an experienced neonatologist can provide valuable information on early WM changes such as prolonged echodensities that could potentially lead to a diffuse injury.

Prevalence of Capillaria hepatica in non-commensal rodents from a forest area near Dijon, France.

Capillaria hepatica is a zoonotic parasite (nematode) found in the liver of many mammals, especially rodents, worldwide. In this study, 94 non-commensal rodents were trapped in a forest area near Dijon, France, including 65 Apodemus spp. and 29 Myodes glareolus. Pathology was studied on the liver of each rodent. Histological lesions consisting of chronic multifocal granulomatous hepatitis due to both eggs and adult forms of the parasite were observed in the liver of eight M. glareolus and one Apodemus spp. The global prevalence of 9.6 % was significantly higher in M. glareolus (27.6 %) compared to Apodemus spp. (1.5 %) living in the same ecosystem. No significant difference in the infection rate was found between males and females of M. glareolus. Gross pathological lesions compatible with capillariasis were observed in four of nine rodents. These results raise the role of wild rodents in the maintenance of capillariasis in nature, and their possible role in the transmission to humans.

Nasal cavity lobular capillary hemangioma due to insect sting.

INTRODUCTION: Lobular capillary hemangioma is a frequent benign vascular inflammatory lesion of the skin tissue. It rarely reaches the mucous membrane, and the nasal fossa involvement is exceptional. CASE REPORT: A 68-year-old woman presented with an ulcerous hemorrhagic mass blocking the left nasal fossa, which had appeared a few weeks after a wasp sting in the nose. The insect was evacuated only three weeks after the sting. The clinical and radiological data suggested malignancy. Biopsy under local anesthesia proved non-contributory and was complicated by 1 week's hospitalization for severe nosebleed. Surgical excision under video-endoscopy confirmed diagnosis. At 31 months' follow-up, the patient was free of recurrence. DISCUSSION/CONCLUSION: The pathogeny of lobular capillary hemangioma is uncertain. No previous cases affecting the mucous membrane after insect sting have been reported. Except in the typical contexts of long-term packing or pregnancy, diagnosis can be difficult and misleading. It can mimic a malignant pathology. Its rich vascularization requires caution during biopsy, and the risk of recurrence requires excision to be complete.

Embryonic and fetal development in - pigmy rice rat - Oligoryzomys sp. (Rodentia, Sigmodontinae) and its significance for being a new experimental model.

Oligoryzomys (Cricetidae, Sigmodontinae) is a common rodent genus from South America that includes a couple of very similar species. Related species have been used as experimental model for understanding several diseases for which these species are reservoirs. In order to provide a better understanding of the embryological aspects of this group, herein we showed data on the embryonic and fetal development in Oligoryzomys sp. Eight specimens of different stages of gestation were obtained from the Collection of the Zoology Museum of University of Sao Paulo, Brazil. Gestational ages were estimated by crown-rump-length according to Evans and Sack (1973). To address our analysis after examining the gross morphology, tissues from several organs were processed for light and scanning electron microscopy. Morphological data on the systems (nervous system, cardiorespiratory system, intestinal tract and urogenital system) were described in detail. Finally, the findings were compared with what is known about embryological aspects in other rodent species in order to establish similarities and differences during the organogenesis in different species.

Neurological Soft Signs and Corpus Callosum morphology in schizophrenia.

OBJECTIVE: Neurological Soft Signs (NSS) have been found to be more prevalent in schizophrenic patients. A breakdown in intracortical functional connectivity, including interhemispheric communication, has been suggested in the pathogenesis of schizophrenia. Indeed, problems with interhemispheric information transfer via the Corpus Callosum (CC) have been documented in schizophrenics. Our study goal was to relate NSS to CC morphology. METHODS: CC Magnetic Resonance Imaging (MRI) measurements were collected from 29 right-handed male schizophrenia inpatients. NSS were evaluated employing the Neurological Evaluation Scale (NES). We examined the scores obtained from the NES total and the three NES subscales: Integrative Sensory Function, Motor Coordination, and Sequencing Of Complex Motor Acts. We compared CC morphology of patients with "high" NSS with that of patients with "low" NSS. Correlation analyses were performed to further clarify the relationship between CC size, NSS, and total lifetime antipsychotic consumption. RESULTS: Patients with "high" scores at the Sequencing Of Complex Motor Acts subscale showed a smaller CC rostral body, whereas patients with "high" scores at the Integrative Sensory Function subscale showed a smaller CC splenium. For both the NES total and the Sequencing Of Complex Motor Acts subscale, "high" scores were accompanied by an increase of the CC genu. Correlation analyses revealed a significant inverse correlation between the CC rostral body size and the Sequencing Of Complex Motor Acts subscale score. In addition, a significant positive correlation was shown between the CC genu size and both the NES total and the Sequencing Of Complex Motor Acts subscale scores. The presence of NSS and the accompanying CC structural abnormalities were independent on antipsychotic treatment. CONCLUSIONS: Our data provide evidence for an association between NSS and CC morphology and further support the hypothesis of a disturbed interhemispheric functional connectivity in schizophrenia.

Adenocarcinoma of the upper esophagus.

Glandular heterotopia of the upper esophagus is a congenital abnormality that is frequently discovered during upper digestive tract endoscopy (in 0.26-4.9% of cases), but usually with no malignant potential. Indeed, adenocarcinoma of the upper esophagus related to such lesions is a rare entity. We report here the 27th observation of this rare type of tumor in an 87-year-old man complaining of cervical dysphagia. This adenocarcinoma had developed from an area of gastric heterotopia 3 cm below the upper sphincter of the esophagus. The treatment regimen was based on exclusive radiochemotherapy, which led to a complete endoscopic response at the end of treatment. The patient's symptom-free survival was six months and overall survival was 17 months from diagnosis. This case of a rare tumor of the upper esophagus raises the question of whether the detection and surveillance of this type of heterotopia would be useful and, thus, to be recommended.

[Sporotrichoid topographic distribution and Mycobacterium marinum grown on a subdermal contraceptive implant]. / Dissémination lymphangitique et greffe sur implant contraceptif de Mycobacterium marinum.

We report a 37-year-old woman who presented a cutaneous papulonodular skin eruption with sporotrichoid topographic distribution. The diagnosis of Mycobacterium marinum infection was obtained with the bacteriological examination of a cutaneous biopsy and related to cleaning her aquarium at home. Mycobacteriological grown on a subdermal contraceptive implant had not been published before.

Influence of obstetric complication severity on brain morphology in schizophrenia: an MR study.

INTRODUCTION: The purpose of this study was to determine if a causal relationship exists between obstetric complications (OCs) severity and linear magnetic resonance (MR) measurements of brain atrophy in patients with schizophrenia. MATERIALS AND METHODS: Linear measurements of ventricular enlargement (bifrontal span, Evans ratio, and bicaudate ratio) and hippocampal atrophy (interuncal distance) were completed on MR images obtained in 47 patients with schizophrenia. Regression analysis was used to look at association with OCs severity, assessed by the "Midwife protocol" of Parnas and colleagues. The relationship between MR measurements and phenomenologic variables such as age at onset, illness duration, and exposure to antipsychotic medications was explored. The relationship between MR measurements, OCs severity, and symptom presentation was also investigated. RESULTS: OCs severity was significantly associated with MR measurements of ventricular enlargement (bifrontal span, Evans ratio). As the severity of OCs increased, bifrontal span and Evans ratio increased. This effect was independent of age at onset, illness duration, or even antipsychotic treatment. Interestingly, bifrontal span, Evans ratio, and OCs severity score all showed a significant positive correlation with hallucinatory symptomatology. CONCLUSION: Although confirmatory studies are needed, our findings would support the idea that environmental factors, in this case severe OCs, might partly contribute to ventricular abnormalities in schizophrenia.

[Intervertebral instability]. / Imaging dell'instabilità vertebrale lombare su base degenerativa.

The clinic diagnosis of degenerative lumbar intervertebral instability is a controversial topic and have not yet been clarified clinical criteria for to define this condition with accuracy. Although the lumbar pain is the most common symptom in patients who have lumbar intervertebral instability its clinical presentation is not specific; moreover in patients with lumbar pain there are no agreed signs and symptoms that can be truly attributable to instability. Despite better imaging techniques of testing spinal instability there is not a clear relations between radiologic signs of instability and clinical symptoms. It is, however, still far from unanimous definition of degenerative lumbar intervertebral instability accepted from all specialists involved in diagnosis and treatment of this condition; however, seem there is most agree about suspected vertebral instability. Nevertheless this unresolved topic, it is possible to state that imaging play an increasing role in diagnosis and management of patients with suspected instability. The aim of this study is to investigate the different imaging modalities most indicated in diagnosis if vertebral instability and whether degenerative change can be associated with lower back pain.

[Imaging of acute brain inflammatory disease]. / Imaging della patologia infiammatoria acuta dell'encefalo.

The central nervous system inflammatory disease can be due to any kind of infective agent (bacterial viral, fungal and parasitic), but entails also multiple sclerosis, a primary demyelinating disease in which the causal agent is unknown. MR imaging is, in most often, the procedure of choice, due to her multiplanar and multiparametric imaging, and to her better contrast resolution. The post-contrast imaging with double dose of gadolinium and late sequences enable visualisation of smallest pathologic foci or slightest blood-brain barrier alterations, with a sensibility very higher than post-contrast CT scan. In addition, RM provide to many functional informations, by means of diffusion, perfusion and spectroscopy studies, Bold technique for cortical activation studies and Fiber Tracking technique, in order to demonstrate pathologic modification earlier than they are evident on morphologic imaging. Functional imaging is also employed to monitor response to treatment and damage reversibility.

[Vertebral fractures: radiological diagnosis, differential diagnosis and prognostic implications]. / Fratture vertebrali: diagnosi radiologica, diagnosi differenziale e implicazioni prognostiche.

Vertebral fractures are a relevant problem for the heavy clinical implications and carrying disability. Vertebral fractures can be traumatic or pathologic, the latter can be benign or malignant, both mostly frequent in the elderly. An initial approach to this issue can use plain radiographs, but the correct extension and evaluation must involve CT and MR imaging. In particular MR is a useful tool for the prognostic evaluation of spine marrow injuries and the differential diagnosis of osteoporotic and metastatic fractures.