Cyanobacteria and the Great Oxidation Event:Evidence from genes and fossils

Cyanobacteria are among the most ancient of evolutionary lineages, oxygenic photosynthesizers that may have originated before 3.0 Ga, as evidenced by free oxygen levels. Throughout the Precambrian, cyanobacteria were one of the most important drivers of biological innovations, strongly impacting early Earth's environments. At the end of the Archean Eon, they were responsible for the rapid oxygenation of Earth's atmosphere during an episode referred to as the Great Oxidation Event (GOE). However, little is known about the origin and diversity of early cyanobacterial taxa, due to: (1) the scarceness of Precambrian fossil deposits; (2) limited characteristics for the identification of taxa; and (3) the poor preservation of ancient microfossils. Previous studies based on 16S rRNA have suggested that the origin of multicellularity within cyanobacteria might have been associated with the GOE. However, single-gene analyses have limitations, particularly for deep branches. We reconstructed the evolutionary history of cyanobacteria using genome scale data and re-evaluated the Precambrian fossil record to get more precise calibrations for a relaxed clock analysis. For the phylogenomic reconstructions, we identified 756 conserved gene sequences in 65 cyanobacterial taxa, of which eight genomes have been sequenced in this study. Character state reconstructions based on maximum likelihood and Bayesian phylogenetic inference confirm previous findings, of an ancient multicellular cyanobacterial lineage ancestral to the majority of modern cyanobacteria. Relaxed clock analyses provide firm support for an origin of cyanobacteria in the Archean and a transition to multicellularity before the GOE. It is likely that multicellularity had a greater impact on cyanobacterial fitness and thus abundance, than previously assumed. Multicellularity, as a major evolutionary innovation, forming a novel unit for selection to act upon, may have served to overcome evolutionary constraints and enabled diversification of the variety of morphotypes seen in cyanobacteria today.</p

Video-assisted thoracic surgery: Risks and benefits

Summary: Background: Thoracoscopy has been used throughout this century, especially in the treatment of pleural disease. The introduction of video-assistance and especially designed instruments such as stapling devices in 1992 led to a worldwide and enthusiastic application for the treatment of a variety of thoracic pathologies. Methods: This report summarizes our experience gained from 1013 consecutive VATS procedures performed since 1990 for various indications in order to clarify its role for surgery of thoracic pathologies. Results: 234 patients underwent VATS for pleural biopsy, 154 for talcage, 163 for pulmonary wedge resections in order to clarify interstitial diseasee or indetermined nodules, 126 for spontaneous pneumothorax, 91 for decortication of empyema, 63 for symphatectomy, 55 for biopsy of mediastinal lesions, 29 for pericardial effusions (fenestration), 25 for lung volume reduction surgery, 17 for excision of mediastinal cysts and 12 for excision of neurogenic tumors of the posterior mediastinum. Conclusions: Our results demonstrate that VATS has gained established acceptance for several indications, however, caution in application of VATS is clearly indicated for some diseases, especially for thoracic malignancie

Co-expressed peptide receptors in breast cancer as a molecular basis for in vivo multireceptor tumour targeting

Breast cancers can express different types of peptide receptors such as somatostatin, vasoactive intestinal peptide (VIP), gastrin-releasing peptide (GRP) and NPY(Y1) receptors. The aim of this in vitro study was to evaluate which is the most appropriate peptide receptor or peptide receptor combination for in vivo diagnostic and therapeutic targeting of breast cancers. Seventy-seven primary breast cancers and 15 breast cancer lymph node metastases were investigated in vitro for their expression of somatostatin, VPAC1, GRP and NPY(Y1) receptors using in vitro receptor autoradiography on successive tissue sections with 125I-[Tyr3]-octreotide, 125I-VIP, 125I-[Tyr4]-bombesin and 125I-[Leu31,Pro34]-PYY respectively. This study identified two groups of tumours: a group of 68 tumours (88%) with at least one receptor expressed at high density (>2,000dpm/mg tissue) that may provide a strong predictive value for successful in vivo targeting, and a group of nine tumours (12%) with no receptors or only a low density of them (<2,000dpm/mg tissue). In the group with high receptor density, 50 of the 68 tumours (74%) expressed GRP receptors, 45 (66%) expressed NPY(Y1) receptors, 25 (37%) expressed VPAC1 receptors and 14 (21%) expressed somatostatin receptors. Mean density was 9,819±530dpm/mg tissue for GRP receptors, 9,135±579dpm/mg for NPY(Y1) receptors, 4,337±528dpm/mg for somatostatin receptors and 3,437±306dpm/mg for VPAC1 receptors. It is of note that tumours expressing NPY(Y1) or GRP receptors, or both, were found in 63/68 (93%) cases. Lymph node metastases showed a similar receptor profile to the corresponding primary tumour. This in vitro study strongly suggests that the combination of radiolabelled GRP and Y1 analogues should allow targeting of breast carcinomas and their lymph node metastases for in vivo peptide receptor scintigraphy and radiotherap

Bronchogenic cyst of the left lower lobe associated with severe hemoptysis

Bronchogenic cysts result from congenital disorders, are often asymptomatic at diagnosis, but complications are not uncommon. We report the case of a 19-year-old woman with severe hemoptysis. This rare presentation of an intrapulmonary bronchogenic cyst should be considered as differential diagnosis in patients with cavernous lesion of a lobe. Surgery was performed as a diagnostic and therapeutic measur

Correlation of perineal ultrasound and lateral chain urethrocystography in the anatomical evaluation of the bladder neck

Although perineal ultrasound has been widely used, no standard values have been published. In 52 women with urinary stress incontinence the following parameters were measured during resting and straining: a) with ultrasound: distance (Dy) between bladder neck and central line of the symphysis, distance (Dx) between bladder neck and lower border of the symphysis, and retrovesical angle β; b) with urethrocystography (UCG): distance H between the bladder neck and the SCIPP line, inclination angle α and retrovesical angle β. Dy and H correlated during resting (r=0.608; p<0.001) and straining (r=0.575; p<0.001). The distance Dy of 11mm corresponded to a bladder neck position on the SQIPP line. A rotational descent was detectable when Dx increased from 13mm (± 6.5) during resting to 16mm (±7.8) during straining (p=0.009). It was concluded that perineal ultrasound is valuable for the anatomical evaluation of the bladder neck. This is the first report to better define the position of the bladder based on ultrasonographic measurement

Morbidity and validity of the hemiclamshell approach for thoracic surgery

Objective: This is a prospective study to evaluate the indications and outcome of the hemiclamshell incision (longitudinal partial sternotomy combined with an antero-lateral thoracotomy) as used for a consecutive series of patients requiring surgery for various thoracic pathologies not ideally approached by postero-lateral thoracotomy, sternotomy or thoracoscopy. Methods: All patients with a hemiclamshell incision performed between 1994 and 1998 were prospectively analyzed regarding indications, postoperative morbidity and outcome (clinical examination and pulmonary function testing) in order to validate this incision for thoracic surgery. Results: 25 patients (15 men, 10 women) with an age ranging from 16 to 73 years (mean 43 years) underwent a hemiclamshell incision. The indications for the hemiclamshell approach were (1) chest trauma with massive hemorrhage requiring urgent access to the mediastinum and the ipsilateral pleural space (40%), (2) tumors of the anterior cervico-thoracic junction with suspicion of vascular involvement (28%) and (3) lesions involving both one chest cavity and the mediastinum (32%). The 30-day mortality was 8%. One patient suffered a sternal wound infection, mediastinitis and pleural empyema after a gun shot wound, whereas wound healing was uneventful in all other patients. Analgesic requirements for postoperative pain relief were not increased as compared to those following a standard thoracotomy. At 3 months normal sensitivity of the entire chest wall and intact shoulder girdle function was noted in 90% of the patients. Pulmonary function testing showed no restriction due to the hemiclamshell incision. Conclusions: The hemiclamshell incision is a useful approach in selected patients and does not cause more morbidity or long-term sequelae than a standard thoracotom

Langerhans cell histiocytosis as differential diagnosis of a mediastinal tumor

We describe the case of a 55-year-old man who presented with parasternal swelling. The chest CT scan showed a large tumor of the chest wall infiltrating the subcutaneous tissue. To assume histologic diagnosis an open biopsy was performed. Between the myofibrils a coarse, white tumor with infiltrative growth was noted. Histopathologic examination revealed expanded atrophic skeletal muscle that was infiltrated by histiocytic cells. Numerous eosinophilic granulocytes and lymphocytes CD20 and CD3 positive could be detected and immunohistochemical staining was also positive for S-100 proteins and CD1a. Histologic findings were characteristic of Langerhans cell histiocytosis (LCH). To the best of our knowledge a LCH originating from the mediastinum in an adult as presented has not been previously describe

Pulmonary function testing after operative stabilisation of the chest wall for flail chest

Objective: This is a prospective evaluation of chest wall integrity and pulmonary function in patients with operative stabilisation for flail chest injuries. Methods: From 1990 to 1999, 66 patients (56 men, 10 women; mean age 52.6 years) with antero-lateral flail chest (≧4 ribs fractured at ≧2 sites) underwent surgical stabilisation using reconstruction plates. Clinical assessment and pulmonary function testing were performed at 6 months following surgery. Results: Fifty-five (83%) patients had various combinations of injuries of the thorax, head, abdomen and extremities. Sixty-three (95.5%) patients underwent unilateral and 3 (4.5%) patients bilateral stabilisation with a median delay of 2.8 days (range 0-21 days) from admission. The 30-day mortality was 11% (seven of 66 patients). Immediate postoperative extubation was feasible in 31 of 66 patients (47%) and extubation within 7 days following stabilisation in 56 of 66 patients (85%). No plate dislocation was observed during the follow-up. The shoulder girdle function was intact in 51 of 57 patients (90%). Chest wall complaints were noted in 6 of 57 (11%) patients, requiring removal of implants in three cases. All patients returned to work within a mean period of 8 (range 3-16) weeks following discharge. Pulmonary function testing (n=50) at 6 months after the operation revealed a significant difference of predicted vs. recorded vital capacity (VC) and forced expiratory volume in 1s (FEV1) (P=0.04 and P=0.0001, respectively; Wilcoxon signed-rank test). The median ratio of the recorded and predicted total lung capacity (TLC) was shown to be significantly higher than 0.85 (P=0.0002; Wilcoxon signed-rank test), indicating prevention of pulmonary restriction. Conclusion: Antero-lateral flail chest injuries accompanied by respiratory insufficiency can be effectively stabilised using reconstruction plates. Early restoration of the chest wall integrity and respiratory pump function may be cost effective through the prevention of prolonged mechanical ventilation and restriction-related working incapacit

1,25-Dihydroxycholecalciferol with low-calcium diet reduces acute rejection in rat lung allotransplantation

OBJECTIVES The effect of 1,25-dihydroxycholecalciferol (calcitriol, vitamin D3) with a low-calcium diet on the acute lung allograft rejection in a rat unilateral left lung transplantation model was evaluated. METHODS Three transplantation groups were studied (n=5, male Brown-Norway to Fischer F344, 235±15g body weight): calcitriol and low-calcium diet, low-calcium diet and normal diet. Calcitriol (4μg/kg/day) was injected intraperitoneally for 5 days, starting from the day of transplantation. In addition, two non-transplantation groups were compared: (n=3, Brown-Norway) to measure the level of cytokines, and Fischer F344 receiving calcitriol and a low-calcium diet to measure the serum calcium level. The recipients of transplantation were killed on Day 5 post-transplant. The contralateral right main bronchus and the pulmonary artery were occluded for 5min and blood was drawn for the blood gas analysis, and the grafts were assessed for histology (International Society for Heart and Lung Transplantation 1996/rank scale). Lung levels of interleukin (IL)-2, IL-6, IL-12 and tumour necrosis factor-α (TNF-α) were assessed within the calcitriol and low-calcium diet, low-calcium diet and Brown-Norway groups. The serum calcium level was assessed in the Fischer F344 group. An analysis of variance with Tukey's post hoc test was used to compare the arterial blood oxygen pressure and the lung cytokine expression between groups. A non-parametric Kruskal-Wallis test followed by the Siegel and Castellan post hoc test was used to assess the differences between the groups according to the lung graft rejection grading. Student's paired t-test was used to compare the serum calcium level. RESULTS The arterial PaO2 was significantly higher in the calcitriol and the low-calcium diet groups when compared with low-calcium diet or normal diet groups (356±72mmHg; P<0.05 vs other groups). The arterial and bronchial rejection observed in calcitriol and low-calcium diet group was significantly milder than in the low-calcium diet or normal diet groups (A1-2, B1-2; P<0.05 vs other groups). IL-2 and IL-6 levels were significantly higher in low-calcium diet vs calcitriol and low-calcium diet and Brown-Norway groups. IL-12 and TNF-α did not differ among the groups. There was no significant difference in serum calcium level before and after the treatment in the Fischer F344 group. CONCLUSIONS Calcitriol with a low-calcium diet treatment improves lung function, reduces lung allograft acute rejection, decreases IL-2 and IL-6 allograft expression and does not change the serum calcium level significantl