Identification of early metabolic markers of various degrees of ischemia in the mouse brain by localized H-1 magnetic resonance spectroscopy

Objectives: Magnetic resonance (MR) imaging and spectroscopy (MRS) allow the establishment of the anatomical evolution and neurochemical profiles of ischemic lesions. The aim of the present study was to identify markers of reversible and irreversible damage by comparing the effects of 10-mins middle cerebral artery occlusion (MCAO), mimicking a transient ischemic attack, with the effects of 30-mins MCAO, inducing a striatal lesion. Methods: ICR-CD1 mice were subjected to 10-mins (n = 11) or 30-mins (n = 9) endoluminal MCAO by filament technique at 0 h. The regional cerebral blood flow (CBF) was monitored in all animals by laser- Doppler flowmetry with a flexible probe fixed on the skull with < 20% of baseline CBF during ischemia and > 70% during reperfusion. All MR studies were carried out in a horizontal 14.1T magnet. Fast spin echo images with T2-weighted parameters were acquired to localize the volume of interest and evaluate the lesion size. Immediately after adjustment of field inhomogeneities, localized 1H MRS was applied to obtain the neurochemical profile from the striatum (6 to 8 microliters). Six animals (sham group) underwent nearly identical procedures without MCAO. Results: The 10-mins MCAO induced no MR- or histologically detectable lesion in most of the mice and a small lesion in some of them. We thus had two groups with the same duration of ischemia but a different outcome, which could be compared to sham-operated mice and more severe ischemic mice (30-mins MCAO). Lactate increase, a hallmark of ischemic insult, was only detected significantly after 30-mins MCAO, whereas at 3 h post ischemia, glutamine was increased in all ischemic mice independently of duration and outcome. In contrast, glutamate, and even more so, N-acetyl-aspartate, decreased only in those mice exhibiting visible lesions on T2-weighted images at 24 h. Conclusions: These results suggest that an increased glutamine/glutamate ratio is a sensitive marker indicating the presence of an excitotoxic insult. Glutamate and NAA, on the other hand, appear to predict permanent neuronal damage. In conclusion, as early as 3 h post ischemia, it is possible to identify early metabolic markers manifesting the presence of a mild ischemic insult as well as the lesion outcome at 24 h.

Novel relationship between Vegf expression and retinal pigmented epithelium permeability following light damage in the mouse retina

Purpose:In the retina, the balance between pro- and anti-angiogenic factors is critical for angiogenesis control but is also involved in cell survival and maintenance. For instance, the anti-angiogenic factor PEDF is neuroprotective for photoreceptors (PRs) in models of retinal degeneration. We previously reported upregulation of VEGF (24h to 48h post lesion) in the light-damage (LD) model. Furthermore, systemic delivery of PEDF, as well as lentiviral gene transfer of an anti-VEGF antibody rescue PRs from cell death. Studies in vitro show that VEGF induces retinal endothelial cells apoptosis via the alteration of the Akt1/p38 MAPK signalling pathway under hypoxic conditions. Thus, in this study, we investigate the effect of high levels of VEGF on retinal pigmented epithelium (RPE) permeability and molecular targets expression after light-induced PR degeneration. Methods:To characterize the action of VEGF in the retina during the course of LD, we exposed adult Balb/c mice to 5'000 lux for 1h, and we collected neural retinas and eye-cups (containing RPE) at different time points after the LD. We analysed protein expression by Elisa and Western blotting. In order to study RPE cell permeability after the LD we stained β-catenin on flat mounted RPE. Results:In the neural retina, preliminary results indicate that high levels of VEGF induce a significant upregulation of VEGF receptor 2, whereas VEGF receptor 1 expression is decreased. Concomitantly with VEGF upregulation, LD increases the Src phosphorylation between 24h to 48h. Furthermore, we observe that β-catenin translocates to the cytoplasm of RPE cells between 24h to 36h after the lesion, indicating an increase on the RPE permeability, which could contribute indirectly to the deleterious effect of VEGF observed during light-induced PR apoptosis. Conclusions:This study further involves VEGF in LD and highlights the prime importance of angiogenic factor balance for PR survival. Our results suggest that PR apoptosis is augmented by RPE cell permeability, which may induce high level of VEGF and could be deleterious. The specific action of RPE permeability on PR survival and the role of Src in the retina are under investigation.

Well-differentiated papillary mesothelioma of the tunica vaginalis testis: imaging on Tc-99m heat-denatured red blood cell scintigraphy.

An 18-year-old man presented with a growing painless left scrotal mass. Sonography showed a hydrocele and a homogeneous, well-encapsulated left extratesticular mass with similar echogenicity as the normal testis, suggestive of a splenogonadal fusion. To substantiate the diagnosis, the patient underwent Tc-99m heat-denatured red blood cell scintigraphy showing normal physiological hyperactivity in the spleen but activity similar to the blood pool projecting on the upper part of the left testis. This made testicular splenic tissue less likely. The patient underwent resection and histopathology revealed a well-differentiated papillary mesothelioma. Inguinal orchidectomy was subsequently performed and the patient was free of recurrence at 18 months.

Premature epiphyseal closure in an adolescent treated by retinoids for acne: an unusual cause of anterior knee pain.

Retinoids are effective and widely prescribed in the treatment of severe acne. However their use can be associated with numerous side effects. Some rare cases of premature epiphyseal closure were reported. We present the case of a sixteen-year-old soccer player referred for progressive anterior pain in both knees, evoking a patellar problem. Careful pharmacological questioning revealed use of isotretinoin for several months. MRI findings showed an irregularity of the growth plate and an important metaphyso-epiphyseal oedema, more noticeable in the left knee. Retinoid-induced premature epiphyseal closure was diagnosed. The treatment was stopped, with a resolution of pain within two months. After recovery a persisting small sequelar thumbprint-like growth plate lesion was observed on the control MRI. Retinoids induce an invasion of the growth plate by osteoclasts and a decrease in proteoglycans synthesis. It seems that the knee is the most affected joint. This complication being rare, a radiological follow-up of the young patients treated by retinoids is not proposed.

Evaluation of high frequency jet ventilation in patients undergoing percutaneous thermal ablation

Purpose: To evaluate the use of high frequency jet ventilation (HFJV) in patients undergoing percutanous thermal ablation procedures.Materials: From may to september 2011 patients with lung, liver or kidney tumors suitable for percutanous thermal ablation were prospectively enrolled to be treated under general anesthesia using HFJV instead of conventional positive pressure ventilation (PPV). Our primary endpoint was feasability of HFJV during percutanous ablation, our secondary endpoints were assessment of breathing related movements by image fusion (CT/US), precision and ease of needle placement by number of CT aquisition/needle reposition and procedure related complications.Results: Twenty-nine patients (21 males, 8 females mean age 66.2 years) with 30 liver tumors, 1 kidney tumors and 6 lung tumors were included. Tumor ablation was performed by radiofrequency (RFA) in 26 cases, microwaves ( MWA) in 2 and cryoablation (CRA) in 1. The ablation procedure could be completed under HFJV in 22 patients. In 2 patients HFVJ had to be stopped in favor of PPV because the tumor was better seen under PPV. HFJV was not performed in 5. Breathing related movements of the target lesion in the cranio-caudal direction as estimated by image fusion were always inferior to 5mm compared to 20mm when patients are under PPV. Needle placement was straightforward under CT as well as US. No patient needed needle repositionning before ablation. We did not observe any HFJV related complications.Conclusions: HFJV significantly reduces breathing movements of target lesion during percutaneous ablation procedures. It does not seem to cause any particular complication. However in some cases such as tumors located at the base of the lungs or in the dome of the liver, the target may be best seen under PPV.

Detection rate of FNA cytology in medullary thyroid carcinoma: a meta-analysis.

BACKGROUND: The early detection of medullary thyroid carcinoma (MTC) can improve patient prognosis, because histological stage and patient age at diagnosis are highly relevant prognostic factors. As a consequence, delay in the diagnosis and/or incomplete surgical treatment should correlate with a poorer prognosis for patients. Few papers have evaluated the specific capability of fine-needle aspiration cytology (FNAC) to detect MTC, and small series have been reported. This study conducts a meta-analysis of published data on the diagnostic performance of FNAC in MTC to provide more robust estimates. RESEARCH DESIGN AND METHODS: A comprehensive computer literature search of the PubMed/MEDLINE, Embase and Scopus databases was conducted by searching for the terms 'medullary thyroid' AND 'cytology', 'FNA', 'FNAB', 'FNAC', 'fine needle' or 'fine-needle'. The search was updated until 21 March 2014, and no language restrictions were used. RESULTS: Fifteen relevant studies and 641 MTC lesions that had undergone FNAC were included. The detection rate (DR) of FNAC in patients with MTC (diagnosed as 'MTC' or 'suspicious for MTC') on a per lesion-based analysis ranged from 12·5% to 88·2%, with a pooled estimate of 56·4% (95% CI: 52·6-60·1%). The included studies were statistically heterogeneous in their estimates of DR (I-square >50%). Egger's regression intercept for DR pooling was 0·03 (95% CI: -3·1 to 3·2, P = 0·9). The study that reported the largest MTC series had a DR of 45%. Data on immunohistochemistry for calcitonin in diagnosing MTC were inconsistent for the meta-analysis. CONCLUSIONS: The presented meta-analysis demonstrates that FNAC is able to detect approximately one-half of MTC lesions. These findings suggest that other techniques may be needed in combination with FNAC to diagnose MTC and avoid false negative results.

Stress radiography and posterior pathological laxity of knee: comparison between two different techniques.

Stress radiographs have been recommended in order to obtain a better objective quantification of abnormal compartment knee motion. This tool has showed to be superior in quantifying a posterior cruciate ligament (PCL) lesion compared to clinical or arthrometer evaluation. Different radiographic techniques have been described in literature to quantify posterior pathological laxity. In this study we evaluated the total amount of posterior displacement (PTD) and side to side difference (SSD), before and after surgical reconstruction of PCL or PCL and posterolateral complex (PLC), using two different stress radiography techniques (Telos stress and kneeling view). Twenty patients were included in this study. We found a statistical significant difference about both total PTD and SSD among the two techniques preoperatively and at follow-up, with greatest values occurring using the kneeling view. Although stress radiographies has been introduced to allow an objective quantification of laxity in ligamentous injured knee, we believe that further studies on a large numbers of subjects are required to define the relationship between PTD values, measured with stress knee radiography, particularly using kneeling view, and ligamentous knee injury, in order to obtain a real useful tool in the decision making process, as well as to evaluate the outcome after ligamentous surgery.

Brain aging in the oldest-old.

Nonagenarians and centenarians represent a quickly growing age group worldwide. In parallel, the prevalence of dementia increases substantially, but how to define dementia in this oldest-old age segment remains unclear. Although the idea that the risk of Alzheimer's disease (AD) decreases after age 90 has now been questioned, the oldest-old still represent a population relatively resistant to degenerative brain processes. Brain aging is characterised by the formation of neurofibrillary tangles (NFTs) and senile plaques (SPs) as well as neuronal and synaptic loss in both cognitively intact individuals and patients with AD. In nondemented cases NFTs are usually restricted to the hippocampal formation, whereas the progressive involvement of the association areas in the temporal neocortex parallels the development of overt clinical signs of dementia. In contrast, there is little correlation between the quantitative distribution of SP and AD severity. The pattern of lesion distribution and neuronal loss changes in extreme aging relative to the younger-old. In contrast to younger cases where dementia is mainly related to severe NFT formation within adjacent components of the medial and inferior aspects of the temporal cortex, oldest-old individuals display a preferential involvement of the anterior part of the CA1 field of the hippocampus whereas the inferior temporal and frontal association areas are relatively spared. This pattern suggests that both the extent of NFT development in the hippocampus as well as a displacement of subregional NFT distribution within the Cornu ammonis (CA) fields may be key determinants of dementia in the very old. Cortical association areas are relatively preserved. The progression of NFT formation across increasing cognitive impairment was significantly slower in nonagenarians and centenarians compared to younger cases in the CA1 field and entorhinal cortex. The total amount of amyloid and the neuronal loss in these regions were also significantly lower than those reported in younger AD cases. Overall, there is evidence that pathological substrates of cognitive deterioration in the oldest-old are different from those observed in the younger-old. Microvascular parameters such as mean capillary diameters may be key factors to consider for the prediction of cognitive decline in the oldest-old. Neuropathological particularities of the oldest-old may be related to "longevity-enabling" genes although little or nothing is known in this promising field of future research.

Reversible acquired epileptic frontal syndrome and CSWS suppression in a child with congenital hemiparesis treated by hemispherotomy.

A boy with a right congenital hemiparesis due to a left pre-natal middle cerebral artery infarct developed focal epilepsy at 33 months and then an insidious and subsequently more rapid, massive cognitive and behavioural regression with a frontal syndrome between the ages of 4 and 5 years with continuous spike-waves during sleep (CSWS) on the EEG. Both the epilepsy and the CSWS were immediately suppressed by hemispherotomy at the age of 5 years and 4 months. A behavioural-cognitive follow-up prior to hemispherotomy, an per-operative EEG and corticography and serial post-operative neuropsychological assessments were performed until the age of 11 years. The spread of the epileptic activity to the "healthy" frontal region was the cause of the reversible frontal syndrome. A later gradual long-term but incomplete cognitive recovery, with moderate mental disability was documented. This outcome is probably explained by another facet of the epilepsy, namely the structural effects of prolonged epileptic discharges in rapidly developing cerebral networks which are, at the same time undergoing the reorganization imposed by a unilateral early hemispheric lesion. Group studies on the outcome of children before and after hemispherectomy using only single IQ measures, pre- and post-operatively, may miss particular epileptic cognitive dysfunctions as they are likely to be different from case to case. Such detailed and rarely available complementary clinical and EEG data obtained in a single case at different time periods in relation to the epilepsy, including per-operative electrophysiological findings, may help to understand the different cognitive deficits and recovery profiles and the limits of full cognitive recovery.

REDUCTION OF MIGRAINES AFTER TREATMENT OF HEREDITARYHEMORRHAGIC TELANGIECTASIA (HHT)

Background: Pulmonary arteriovenous malformations (PAVMs) due to hereditaryhemorrhagic telangiectases (HHT) is associated with paradoxical strokes, brainabcesses, and increased prevalence of migraines. We report a patient in whom wefound a relationship between PAMVs and a reduction in frequency of migrainewith aura after the treatment of the first pulmonary malformation.Patient and methods: A 67-year-old woman developed migraine with visual auraand major epistaxis during childhood. A PAVM is discovered and surgically removedin 1969. Migraines nearly disappeared during several years, after which theystarted to reappear progressively. A HHT syndrome is diagnosed based on recurrentepistaxis, the development of cutaneous telangiectases and a positive family history.She suffered a left subcortical stroke in 2008. Perfusion CT, chest radiography,thoracic CT-angiography, contrast echocardiography, contrast transcranial Dopplerand cerebral MRI were performed.Results: Perfusion CT showed previous asymptomatic strokes in cerebellum andbasal ganglia. 4 PAMVs were confirmed on the chest x-ray whose structural conformationis identified on thoracic CT. Contrast echocardiography and transcranialDoppler showed a massive right to left shunt. It is planned to embolize the 4PAVMs, and migraine frequency will now be prospectively assessed.Conclusion: This patient with a pulmonary arteriovenous malformation showeda reduced migraine frequency after resection of her lung lesion. This suggests acausal relationship between a right to left shunt and migraine, as discussed inpatients with patent foramen ovale.

Oxidative stress activation of miR-125b is part of the molecular switch for Hailey-Hailey disease manifestation.

Hailey-Hailey disease (HHD) is an autosomal dominant disorder characterized by suprabasal cutaneous cell separation (acantholysis) leading to the development of erosive and oozing skin lesion. Micro RNAs (miRNAs) are endogenous post-transcriptional modulators of gene expression with critical functions in health and disease. Here, we evaluated whether the expression of specific miRNAs may play a role in the pathogenesis of HHD. Here, we report that miRNAs are expressed in a non-random manner in Hailey-Hailey patients. miR-125b appeared a promising candidate for playing a role in HHD manifestation. Both Notch1 and p63 are part of a regulatory signalling whose function is essential for the control of keratinocyte proliferation and differentiation and of note, the expression of both Notch1 and p63 is downregulated in HHD-derived keratinocytes. We found that both Notch1 and p63 expression is strongly suppressed by miR-125b expression. Additionally, we found that miR-125b expression is increased by an oxidative stress-dependent mechanism. Our data suggest that oxidative stress-mediated induction of miR-125b plays a specific role in the pathogenesis of HHD by regulating the expression of factors playing an important role in keratinocyte proliferation and differentiation.

The protective capacities of histone H1 against experimental murine cutaneous leishmaniasis.

In a murine model of experimental cutaneous leishmaniasis, we investigated the protection elicited by injection of histone H1 isolated from parasites by perchloric extraction, of a H1 recombinant protein produced in E. coli, and of H1 long and short synthetic peptides, against infection by L. major. Partial protection was achieved in most of the animals as shown by reduction in lesion size, upon immunization with histone H1 or its peptides, provided that the region 1-60 was present in the molecule. These observations argue in favor of a thorough examination of the possibility of including histone H1 described here in a cocktail vaccine against human leishmaniasis.

Corneal Opacities in Trisomy 8 Mosaic Syndrome : Clinical, Histologic and Genetic Features

Purpose: To describe the clinical, histologic and genetic findings of corneal opacities in the trisomy 8 mosaic syndrome. Methods: 3 children aged 8 years (Patients A), 6 years (Patients B) and 1 month (Patients C) respectively, were referred with corneal opacities for ophthalmologic evaluation. The 2 older patients had been previously diagnosed with trisomy 8 mosaicism, while the third was diagnosed after the ocular examination. Automated lamellar keratoplasty (ALTK) was performed on the most amblyopic eye. Histopathologic analysis with immunohistochemical markers and cytogenetic studies by FISH using haploid probes for chromosome 8 and chromosome 16 (control) were performed on the excised corneal lesion. Results: All patients presented vascularized corneal opacities involving the superficial stroma, and amblyopia with a bilateral involvement in two of them (Patients A and B). Post-operative follow-up (range 6-20 months) was satisfactory, with the graft remaining clear and improved visual acuity, allowing iso-acuity and stereoscopy in the one month old child (Patients C). The clinically observed corneal opacities corresponded histopathologically to the replacement of the normal anterior corneal stroma by a choristomatous loose richly vascularized connective tissue containing mucopolysacharides. Bowman's membrane was absent. There were no adnexal structures. The overlaying epithelium expressed keratin 3 in all three cases. Keratin 19 was found in the suprabasal epithelial cells in one case but was absent in the other cases. There were no expression of keratin 7 and 1 as well as MUC5AC in the epithelial cells. FISH analysis from 100 interphase cells of the affected tissue and normal conjontival probe revealed normal diploid cells. Conclusions: In this series, the corneal opacities associated with trisomy 8 mosaic syndrome share a common clinical, histopathological and genetic features. ALTK should be considered at diagnosis to prevent amblyopia in these children.

The kidney during hibernation and arousal from hibernation. A natural model of organ preservation during cold ischaemia and reperfusion.

BACKGROUND: During hibernation the kidney is in a hypothermic condition where renal blood flow is minimal and urine production is much reduced. Periodical arousal from hibernation is associated with kidney reperfusion at increasing body temperature, and restored urine production rate. METHODS: To assess the degree of structural preservation during such extreme conditions, the kidney cortex was investigated by means of electron microscopy in the dormouse Muscardinus avellanarius during winter hibernation, arousal from hibernation and the summer active period. RESULTS: Results show that the fine structure of the kidney cortex is well preserved during hibernation. In the renal corpuscle, a sign of slight lesion was the focal presence of oedematous endothelial cells and/or podocytes. Proximal convoluted tubule cells showed fully preserved ultrastructure and polarity, and hypertrophic apical endocytic apparatus. Structural changes were associated with increased plasma electrolytes, creatinine and urea nitrogen, and proteinuria. During the process of arousal the fine structure of the kidney cortex was also well maintained. CONCLUSION: These results demonstrate that dormice are able to fully preserve kidney cortex structure under extreme conditions resembling e.g. severe ischaemia or hypothermic organ storage for transplantation, and reperfusion. Elucidation of the mechanisms involved in such a natural model of organ preservation could be relevant to human medicine.

Nonenzymatic oxidation of trienoic fatty acids contributes to reactive oxygen species management in Arabidopsis.

In higher plants such as Arabidopsis thaliana, omega-3 trienoic fatty acids (TFAs), represented mainly by alpha-linolenic acid, serve as precursors of jasmonic acid (JA), a potent lipid signal molecule essential for defense. The JA-independent roles of TFAs were investigated by comparing the TFA- and JA-deficient fatty acid desaturase triple mutant (fad3-2 fad7-2 fad8 (fad3 fad7 fad8)) with the aos (allene oxide synthase) mutant that contains TFAs but is JA-deficient. When challenged with the fungus Botrytis, resistance of the fad3 fad7 fad8 mutant was reduced when compared with the aos mutant, suggesting that TFAs play a role in cell survival independently of being the precursors of JA. An independent genetic approach using the lesion mimic mutant accelerated cell death2 (acd2-2) confirmed the importance of TFAs in containing lesion spread, which was increased in the lines in which the fad3 fad7 fad8 and acd2-2 mutations were combined when compared with the aos acd2-2 lines. Malondialdehyde, found to result from oxidative TFA fragmentation during lesion formation, was measured by gas chromatography-mass spectrometry. Its levels correlated with the survival of the tissue. Furthermore, plants lacking TFAs overproduced salicylic acid (SA), hydrogen peroxide, and transcripts encoding several SA-regulated and SA biosynthetic proteins. The data suggest a physiological role for TFAs as sinks for reactive oxygen species.