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Background: Chromatin provides a tunable platform for gene expression control. Besides the well-studied core nucleosome, H1 linker histones are abundant chromatin components with intrinsic potential to influence chromatin function. Well studied in animals, little is known about the evolution of H1 function in other eukaryotic lineages for instance plants. Notably, in the model plant Arabidopsis, while H1 is known to influence heterochromatin and DNA methylation, its contribution to transcription, molecular, and cytological chromatin organization remains elusive., Results: We provide a multi-scale functional study of Arabidopsis linker histones. We show that H1-deficient plants are viable yet show phenotypes in seed dormancy, flowering time, lateral root, and stomata formation-complemented by either or both of the major variants. H1 depletion also impairs pluripotent callus formation. Fine-scale chromatin analyses combined with transcriptome and nucleosome profiling reveal distinct roles of H1 on hetero- and euchromatin: H1 is necessary to form heterochromatic domains yet dispensable for silencing of most transposable elements; H1 depletion affects nucleosome density distribution and mobility in euchromatin, spatial arrangement of nanodomains, histone acetylation, and methylation. These drastic changes affect moderately the transcription but reveal a subset of H1-sensitive genes., Conclusions: H1 variants have a profound impact on the molecular and spatial (nuclear) chromatin organization in Arabidopsis with distinct roles in euchromatin and heterochromatin and a dual causality on gene expression. Phenotypical analyses further suggest the novel possibility that H1-mediated chromatin organization may contribute to the epigenetic control of developmental and cellular transitions.

The spatial organization of chromatin can be subject to extensive remodeling in plant somatic cells in response to developmental and environmental signals. However, the mechanisms controlling these dynamic changes and their functional impact on nuclear activity are poorly understood. Here, we determined that light perception triggers a switch between two different nuclear architectural schemes during Arabidopsis postembryonic development. Whereas progressive nucleus expansion and heterochromatin rearrangements in cotyledon cells are achieved similarly under light and dark conditions during germination, the later steps that lead to mature nuclear phenotypes are intimately associated with the photomorphogenic transition in an organ-specific manner. The light signaling integrators DE-ETIOLATED 1 and CONSTITUTIVE PHOTOMORPHOGENIC 1 maintain heterochromatin in a decondensed state in etiolated cotyledons. In contrast, under light conditions cryptochrome-mediated photoperception releases nuclear expansion and heterochromatin compaction within conspicuous chromocenters. For all tested loci, chromatin condensation during photomorphogenesis does not detectably rely on DNA methylation-based processes. Notwithstanding, the efficiency of transcriptional gene silencing may be impacted during the transition, as based on the reactivation of transposable element-driven reporter genes. Finally, we report that global engagement of RNA polymerase II in transcription is highly increased under light conditions, suggesting that cotyledon photomorphogenesis involves a transition from globally quiescent to more active transcriptional states. Given these findings, we propose that light-triggered changes in nuclear architecture underlie interplays between heterochromatin reorganization and transcriptional reprogramming associated with the establishment of photosynthesis.

Oilseed rape (Brassica napus L.) was formed ~7500 years ago by hybridization between B. rapa and B. oleracea, followed by chromosome doubling, a process known as allopolyploidy. Together with more ancient polyploidizations, this conferred an aggregate 72× genome multiplication since the origin of angiosperms and high gene content. We examined the B. napus genome and the consequences of its recent duplication. The constituent An and Cn subgenomes are engaged in subtle structural, functional, and epigenetic cross-talk, with abundant homeologous exchanges. Incipient gene loss and expression divergence have begun. Selection in B. napus oilseed types has accelerated the loss of glucosinolate genes, while preserving expansion of oil biosynthesis genes. These processes provide insights into allopolyploid evolution and its relationship with crop domestication and improvement., (Copyright © 2014, American Association for the Advancement of Science.)

Using floral-dip, tumorigenesis and root callus transformation assays of both germline and somatic cells, we present here results implicating the four major non-homologous and homologous recombination pathways in Agrobacterium-mediated transformation of Arabidopsis thaliana. All four single mutant lines showed similar mild reductions in transformability, but knocking out three of four pathways severely compromised Agrobacterium-mediated transformation. Although integration of T-DNA into the plant genome is severely compromised in the absence of known DNA double-strand break repair pathways, it does still occur, suggesting the existence of other pathways involved in T-DNA integration. Our results highlight the functional redundancy of the four major plant recombination pathways in transformation, and provide an explanation for the lack of strong effects observed in previous studies on the roles of plant recombination functions in transformation., (© 2013 The Authors The Plant Journal © 2013 John Wiley & Sons Ltd.)

The reprogramming of gene expression appears as the major trend in synthetic and natural allopolyploids where expression of an important proportion of genes was shown to deviate from that of the parents or the average of the parents. In this study, we analyzed gene expression changes in previously reported, highly stable synthetic wheat allohexaploids that combine the D genome of Aegilops tauschii and the AB genome extracted from the natural hexaploid wheat Triticum aestivum. A comprehensive genome-wide analysis of transcriptional changes using the Affymetrix GeneChip Wheat Genome Array was conducted. Prevalence of gene expression additivity was observed where expression does not deviate from the average of the parents for 99.3% of 34,820 expressed transcripts. Moreover, nearly similar expression was observed (for 99.5% of genes) when comparing these synthetic and natural wheat allohexaploids. Such near-complete additivity has never been reported for other allopolyploids and, more interestingly, for other synthetic wheat allohexaploids that differ from the ones studied here by having the natural tetraploid Triticum turgidum as the AB genome progenitor. Our study gave insights into the dynamics of additive gene expression in the highly stable wheat allohexaploids., (© 2012 The Authors. New Phytologist © 2012 New Phytologist Trust.)

Background: Celiac disease (CD) is characterized by a malabsorption syndrom. The bone anomalies are one of the principal complications of this disease. The osteoporosis frequency is high: 3.4% among patients having with CD versus 0.2% in the general population., Aim: To study the bone mineral density during the CD, to compare it to a control group and to determine the anomalies of biochemical markers of bone turn over and level of interleukin 6 cytokin (IL6) in these patients., Methods: All patients with CD have a measurement of bone mineral density by dual-energy x-ray absorptiometry (DXA), a biological exam with dosing calcemia, vitamin D, parathormone (PTH), the osteoblastic bone formation markers (serum osteocalcin, ALP phosphates alkaline), bone osteoclastic activity (C Télopeptide: CTX) and of the IL6., Results: 42 patients were included, with a median age of 33.6 years. 52. 8% of the patients had a low level of D vitamine associated to a high level of PTH. An osteoporosis was noted in 21.5% of patients. No case of osteoporosis was detected in the control group. The mean level of the CTX, ostéocalcine and the IL6 was higher among patients having an osteoporosis or ostéopenia compared to patients with normal bone (p = 0,017). The factors associated with an bone loss (osteopenia or osteoporosis) were: an age > 30 years, a weight <50 kg, a level of ALP phosphates alkaline > 90 UI/ml, an hypo albuminemia < 40 g/l and a level of CTX higher than 1.2., Conclusion: Our study confirms the impact of the CD on the bone mineral statute. The relative risk to have an osteopenia or an osteoporosis was 5 in our series. The measurement of the osseous mineral density would be indicated among patients having a CD.

*The present study aims to understand regulation of gene expression in synthetic and natural wheat (Triticum aestivum) allohexaploids, that combines the AB genome of Triticum turgidum and the D genome of Aegilops tauschii; and which we have recently characterized as genetically stable. *We conducted a comprehensive genome-wide analysis of gene expression that allowed characterization of the effect of variability of the D genome progenitor, the intergenerational stability as well as the comparison with natural wheat allohexaploid. We used the Affymetrix GeneChip Wheat Genome Array, on which 55 049 transcripts are represented. *Additive expression was shown to represent the majority of expression regulation in the synthetic allohexaploids, where expression for more than c. 93% of transcripts was equal to the mid-parent value measured from a mixture of parental RNA. This leaves c. 2000 (c. 7%) transcripts, in which expression was nonadditive. No global gene expression bias or dominance towards any of the progenitor genomes was observed whereas high intergenerational stability and low effect of the D genome progenitor variability were revealed. *Our study suggests that gene expression regulation in wheat allohexaploids is established early upon allohexaploidization and highly conserved over generations, as demonstrated by the high similarity of expression with natural wheat allohexaploids.

To understand key mechanisms leading to stabilized allopolyploid species, we characterized the meiotic behaviour of wheat allohexaploids in relation to structural and genetic changes. For that purpose, we analysed first generations of synthetic allohexaploids obtained through interspecific hybridization, followed by spontaneous chromosome doubling, between several genotypes of Triticum turgidum and Aegilops tauschii wheat species, donors of AB and D genomes, respectively. As expected for these Ph1 (Pairing homoeologous 1) gene-carrying allopolyploids, chromosome pairing at metaphase I of meiosis essentially occurs between homologous chromosomes. However, the different synthetic allohexaploids exhibited progenitor-dependent meiotic irregularities, such as incomplete homologous pairing, resulting in univalent formation and leading to aneuploidy in the subsequent generation. Stability of the synthetic allohexaploids was shown to depend on the considered genotypes of both AB and D genome progenitors, where few combinations compare to the natural wheat allohexaploid in terms of regularity of meiosis and euploidy. Aneuploidy represents the only structural change observed in these synthetic allohexaploids, as no apparent DNA sequence elimination or rearrangement was observed when analysing euploid plants with molecular markers, developed from expressed sequence tags (ESTs) as well as simple sequence repeat (SSR) and transposable element sequences.

Purpose: To describe the CT findings of ruptured pulmonary hydatid cyst (HC) and to establish a progressive CT staging., Patients and Methods: CT scans of 41 patients with pulmonary hydatid cyst complicated by rupture in the bronchi were retrospectively reviewed. We also reviewed the findings in the literature on the rupture of pulmonary hydatid cysts and the Lewall and McCorkell classification and proposed a more detailed staging related to the progression of HC. The Lewall and McCorkell communicating rupture is manifested by a tear of the endocyst with a discharge of the cyst's contents via the bronchioles that were incorporated in the pericyst: -Stage I: signet ring sign; -State II: crescent sign and inverse crescent sign; -Stage III: air bubble sign and honeycomb; Stage IV: air-water level, double arch sin, water lily sign, serpiginous aspect, regular air-water level; -Stage V: dry cyst sign, ball of wool aspect, small bell image, pseudotumoral aspect; -Stage VI: sequela image, residual cavity, and cicatricial image., Results: Seventy-three complicated pulmonary hydatid cysts were included in the analysis and were distributed as follows: stage I (16%), stage II (12.7%), stage III (42.8%), stage IV, double arch sign (2.7%), water lily sign (10%), serpiginous aspect (8.2%), regular air-water level (5.4%), stage V, ball of wool aspect (6.8%), small bell image (15%), pseudotumoral aspect (4%), stage VI, residual cavity (4%) and cicatricial image (2.7%)., Conclusion: Our staging offers more details than the Lewall and McCorkell general classification. Moreover, this staging takes into consideration both the natural evolution of the HC and the particularities of the pulmonary location.

Purpose: Report radiographic aspects and assess the contribution of computed tomography for the diagnosis and search for extension of bronchial carcinoid tumors., Material and Methods: This retrospective study included 20 patients with a bronchial carcinoid tumor. The thoracic exploration included standard chest x-ray, bronchial fibroscopy, computed tomography (CT), and magnetic resonance imaging (MRI) in two patients as well as abdominal ultrasonography to search for extension, performed in all patients., Results: This series included eleven females and nine males, mean age 40 years (age range 21-71 years). Signs on the plain chest x-ray were non-specific: atelectasis (75%), isolated parenchymatous opacity (15%); CT revealed a proximal mass in 85% which was obstructive leading to ventilatory disorders in 80%. CT revealed secondary ventilatory disorders with no individualized mass in one patients (5%), an isolated parenchymatous mass in two (10%) and a endobronchial budding at the origin of the right bronchus with no noted ventilatory disorder in one patient (5%) Tumor calcifications were detected in 30% of patients. Histological there were 17 typical carcinoid tumors and three atypical tumors which were different by their size, locoregional and distant metastatic spread., Conclusion: CT is indispensable for positive diagnosis, and topographic localization of extension of bronchial carcinoid tumors. The main contribution of CT compared with fibroscopy is to demonstrate exobronchial tumor development and upstream pulmonary complications.

Purpose: The objective of this study was to describe the different radiological features of the hydatid cyst of the mediastinum., Materials and Methods: We conducted a retrospective study on 14 patients (seven women, seven men), diagnosed with mediastinal hydatid cyst, aged 13-67 years (mean, 48 years) over a period of 16 years in our hospital where 71 cases of hydatid disease are annually diagnosed. The patients were explored by chest radiography (n=14), chest ultrasonography (n=10), abdomen ultrasonography (n=14), computed tomography (CT scan) (n=13), and magnetic resonance imaging (MRI) (n=8)., Results: The chest x-ray showed an opacity of the anterior (n=11), middle (n=1), and posterior (n=1) mediastinum. The thoracic ultrasound confirmed the liquid nature of the mass with a multivesicular aspect (n=9). CT and thoracic MRI made it possible to precisely locate the mediastinal compartment involved and study the relationship to adjacent structures. A purely mediastinal location was found in only six cases. In the remaining cases, it was associated with hepatic (n=7) and pleural (n=1) locations., Conclusion: Hydatid cysts of the mediastinum are very uncommon. Diagnosis can be made by chest sonography. CT scan is the main tool for diagnosis and the study of possible extension. Our study showed a more frequent location to the anterior mediastinum.

Pulmonary tuberculosis may at times simulate lung carcinoma on bronchoscopic examination or imaging studies. Diagnosis can be delayed and lead to surgical resection. Based on a review of 25 cases, the different CT features are reviewed.

Thoracic involvement of Behcet's disease is unusual but serious. It is related to the well known vascular tropism of the disease. It may involve the superior vena cava, pulmonary arteries, aorta and subclavian vessels. Imaging is useful for diagnosis and assess the degree of thoracic involvement. CT scan and MRI are obviously more accurate than angiography. The spectrum of thoracic manifestations of the disease is presented based on a review of 22 cases.

Pulmonary hyalinizing granuloma is a rare fibrosing nodular disease of the lung characterized by solitary or multiples pulmonary nodules. This report describes two cases of this rare disorder. MRI was available in one case. For the first case, the stability of the lesions and past history of retroperitoneal fibrosis suggested the diagnosis. For the second case, open lung biopsy was required for diagnosis. When multiple nodules are present, metastatic disease cannot be excluded and biopsy may be required. Evolution is usually benign but follow up is necessary.

Introduction: Sarcoidosis is a systemic disease of unknown aetiology that includes a pulmonary or mediastinal component in 90% of cases. The aim of this study is to clarify the contribution of thoracic CT scanning in the diagnosis and differential diagnosis of sarcoidosis and its role in the follow-up and the evaluation of the activity of the disease., Methods: It is a retrospective study of 39 patients with histologically confirmed sarcoidosis. All patients had one or more thoracic CT scans., Results: The most common parenchymatous lesions were lymphatic micronodules and peri-bronchovascular thickening. The right paratracheal chain and the hilar nodes were the most frequently involved., Conclusions: The CT scan is better than the chest x-ray at studying the parenchymal lesions and lymph node involvement in sarcoidosis. It helps in the differential diagnosis of sarcoidosis and other granulomatous disorders, especially tuberculosis. It also allows follow up of patients for the detection of complications, particularly fibrosis. Its role in the assessment of disease activity remains controversial.

The chest wall is an uncommon localization for hydatid disease even in countries where echinococcosis is endemic. Only isolated sporadic cases have been reported in the literature. We reviewed retrospectively 15 patients who underwent surgery for chest wall hydatid disease. Various imaging techniques were used for diagnosis of our cases. These included chest radiograph, thoracic ultrasonography, computed tomography and magnetic resonance imaging. Hydatid cyst involved soft tissues (n=5), ribs and vertebrae (n=5), ribs (n=4) and sternum (n=1). Imaging techniques were of value for diagnosis (radiographs and sonography) and for evaluation of the extent of involvement (CT and MRI). Chest wall hydatidosis requires surgical treatment but recurrence is frequent.

Tracheobronchopathia osteochondroplastica (TO) is a rare benign disorder affecting the trachea and occasionally the bronchi. We report a case of TO presenting as a respiratory insufficiency. Chest radiograph revealed an irregular narrowing of the intra thoracic trachea and a parenchymal consolidation of the left lower lobe. Magnetic resonance examination of the chest showed a diffuse irregular thickening of the trachea and central bronchi, which had an intermediate signal intensity with punctiform low signal intensity suggesting calcifications and no contrast enhancement. The diagnosis was confirmed by bronchoscopy and biopsies.

Tuberculosis of the lung bases is a rare condition that can mimic pneumonia, bronchial carcinoma, lung abscess or bronchiectasis. Diagnostic delays, that can lead to serious complications not amenable to surgical resection, are often the result of repeatedly negative bacteriological examinations. We report a series of 10 cases of tuberculosis of the lung bases collected between 1993 and 1998 that were examined by computerised tomography. The chest x-ray most commonly showed a heterogeneous opacity. On the CT scan this corresponded with an area of alveolar consolidation which, when it was associated with centrilobular micronodules and cavitated nodules and masses, suggested the diagnosis of basal tuberculosis. Indeed the absence of apical lesions and the frequency of involvement of mediastinal and bronchial lymph nodes support the hypothesis of bronchial dissemination of the bacilli from tuberculous nodes. This explanation is supported by the high incidence of endobronchial lesions found at bronchoscopy in this form of tuberculosis.

Hydatidosis, caused by Echinococcus granulosus, is an endemic parasitic disease in Mediterranean countries. The most frequent anatomic locations are liver and lung. Intrathoracic rupture of hydatid cysts situated in the hepatic dome is a serious complication resulting in damage to the pleura, pulmonary parenchyma, and bronchi. From January 1984 to December 1997 we operated on 40 patients with intrathoracic rupture of a hepatic hydatid cyst. Chest roentgenograms showed a shadow of varying size at the base of the hemithorax. Hepatic and thoracic ultrasonography was performed in all cases. The diagnosis of intrathoracic rupture of a liver cyst was confirmed preoperatively in 30 of the 40 cases. Posterolateral thoracotomy was performed in all patients. This transthoracic approach allowed adhesiolysis and treatment of the pleural lesions, pulmonary lesions, and hepatic cyst. Treatment of the diaphragmatic gap is easily done. We performed 15 lobectomies, 10 wedge resections, 16 decortications, and in one patient simple drainage of a voluminous pleuropulmonary and hepatic purulent hydatic collection. The postoperative course was uneventful in 26 cases, but 14 patients had complications, from which 3 patients died. The therapeutic approach depends on ultrasonographic findings. We believe ultrasonography to be the best examination for assessing biliary, hepatic, diaphragmatic, and pleuropulmonary lesions. When an intrathoracic collection is present, thoracotomy must be performed and is sufficient if the biliary tract is safe. An abdominal approach is necessary when biliary duct drainage is required, and it may be sufficient in cases of direct rupture into the bronchi.

Bronchogenic lung cysts are exceptional. We report four cases which raised a problem of differential diagnosis. Our patients included four women and a young boy (age range 12 - 36 years). The first patient consulted for bloody purulent sputum in a context of an infectious syndrome. The second patient had lower right-sided chest pain. The cyst was a fortuitous discovery in the other two cases. In one case, the chest x-ray disclosed a thin-walled cavity of the upper right lobe, confirmed on the CT scan which also evidenced intracavitary partitions. In two other cases, the chest x-ray showed a liquid-filled opacity (one in the lower right lobe and the other in the upper right lobe) and no further specificity on the CT scan. In the last case, a liquid-air cavity was evidenced. Upper right lobectomy was performed for the case with an air-filled cavity and tumorectomy for the other cases. Pathology reported bronchogenic cyst in all cases. The radiological and clinical presentations observed in patients with bronchogenic lung cysts, with or without tracheobronchial communication, are polymorphous, often raising problems of differential diagnosis.

Hydatid cysts of the thigh are uncommon in our country despite a high frequency of hydatic disease which is estimated to affect 5.33% of the general population. Diagnosis is usually made late in the clinical course. Ultrasonography, CT scan and magnetic resonance imaging are the most helpful diagnostic tools. We report a case of a 76-year-old female smoker who had undergone surgery for a hydatic cyst of the right lung at the age of 56 years. In June 1997, the patient was admitted for decompensation of chronic obstructive lung disease. Physical examination revealed a 6 cm painless mass in the right thigh which had developed progressively over the last year. Ultrasonography showed multiple hydatic cysts. Magnetic resonance imaging confirmed the diagnosis, showing interconnected multivesicular cystic formations. Medical treatment was given due to respiratory failure and patient refusal of a surgical procedure.

The thoracic wall is an uncommon localization for tuberculosis, accounting for an estimated 1 to 5% of all cases of bone and joint tuberculosis which themselves account for 15% of all extrapulmonary localizations. Four patients were hospitalized for tuberculosis of the thoracic wall. The first patient, aged 22 years, had sternal tuberculosis with multiple bone localizations. The second patient was 37 years old and had a cold abscess of the peristernal soft tissues with several other bone localizations devoid of clinical manifestations. A third 37-year-old patient had a cold intercostal abscess revealed by a mass in the upper left quadrant of the left breast. In the last patient, 50 years old, tuberculosis of the ribs was associated with a cold tumor of the knee. Together with cases reported in the literature, these observations demonstrate the difficult diagnostic situation presented by tuberculosis of the thoracic wall. Treatment is based on long-duration multi-drug therapy. Surgical resection is rarely indicated. Cure was achieved in our four cases.

Background: The right ventricle is an exceptional localization for hydatic cysts. There is a risk of hydatic embolism and chronic or acute cor pulmonale., Case Report: A 63-year-old-man with an uneventful history was hospitalized for dry cough, exercise-induced dyspnea and bloody expectorations which had developed over the previous year. Multiple and bilateral opacities were visualized on the standard chest x-ray and the right border of the heart showed a bulge in the middle portion. Signs of right-sided hypertrophy were seen on the ECG. Imaging findings led to the diagnosis of multiple organ hydatiasis involving the lung, the liver the mediastinum and a ruptured hydatic cyst in the right ventricle. The cavogram revealed defect images in the superior vena cave and the pulmonary angiogram confirmed the diagnosis of hydatic embolism. Medical treatment was given but the patient died 8 months after diagnosis., Discussion: Hydatic pulmonary embolism generally occurs after rupture of a hydatic cyst in the right ventricle or due to venous migration of daughter vesicles to the right heart then the pulmonary artery. Clinical manifestations are not specific although hemoptisy is the most frequent sign. Positive diagnosis, guided by echocardiographic findings, is based on the pulmonary arteriogram. Prognosis is particularly poor and depends of the patient's general status as well as the number and size of the embolized vessels. Survival rate is poor. Open heart surgery is indicated in localized forms.