1,568 research outputs found
Functional characterisation of substrate-binding proteins to address nutrient uptake in marine picocyanobacteria.
Marine cyanobacteria are key primary producers, contributing significantly to the microbial food web and biogeochemical cycles by releasing and importing many essential nutrients cycled through the environment. A subgroup of these, the picocyanobacteria (Synechococcus and Prochlorococcus), have colonised almost all marine ecosystems, covering a range of distinct light and temperature conditions, and nutrient profiles. The intra-clade diversities displayed by this monophyletic branch of cyanobacteria is indicative of their success across a broad range of environments. Part of this diversity is due to nutrient acquisition mechanisms, such as the use of high-affinity ATP-binding cassette (ABC) transporters to competitively acquire nutrients, particularly in oligotrophic (nutrient scarce) marine environments. The specificity of nutrient uptake in ABC transporters is primarily determined by the peripheral substrate-binding protein (SBP), a receptor protein that mediates ligand recognition and initiates translocation into the cell. The recent availability of large numbers of sequenced picocyanobacterial genomes indicates both Synechococcus and Prochlorococcus apportion >50% of their transport capacity to ABC transport systems. However, the low degree of sequence homology among the SBP family limits the reliability of functional assignments using sequence annotation and prediction tools. This review highlights the use of known SBP structural representatives for the uptake of key nutrient classes by cyanobacteria to compare with predicted SBP functionalities within sequenced marine picocyanobacteria genomes. This review shows the broad range of conserved biochemical functions of picocyanobacteria and the range of novel and hypothetical ABC transport systems that require further functional characterisation
Evolution and oncological outcomes of a contemporary radical prostatectomy practice in a UK regional tertiary referral centre
Objective
To investigate the clinical and pathological trends over a ten-year period for robotic-assisted laparoscopic prostatectomy (RALP) in a UK regional tertiary referral centre.
Patients and Methods
1500 consecutive patients underwent RALP between October 2005 and January 2015. Prospective data was collected on clinic-pathological details at presentation as well as surgical outcomes and compared over time.
Results
The median(range) age of patients throughout the period was 62(35-78) years. The proportion of pre-operative high-grade cases (Gleason sum 8-10) rose from 4.6% in 2005-2008 to 18.2% in 2013-2015 (p<0.0001). In the same periods the proportion of clinical stage T3 cases operated on rose from 2.4% to 11.4% (p<0.0001). Median PSA at diagnosis did not alter significantly. Overall 11.6% of men in 2005-2008 were classified pre-operatively as high-risk by NICE criteria, compared to 33.6% in 2013-2015 (p<0.0001). The corresponding proportions for low-risk cases were 48.6% and 17.3% respectively. Final surgical pathology demonstrated an increase in tumour stage, Gleason grade and nodal status across time. The proportion of pT3 cases rose from 43.2% in 2005-2008 to 55.5% in 2013-15 (p=0.0007), Gleason grade 9-10 tumours increased from 1.8% to 9.1% (p=0.0002) and positive nodal status increased from 1.6% to 12.9% (p<0.0001) between the same periods. Despite this, positive surgical margin rates showed a downward trend in all pT groups across the different eras (p=0.72).
Conclusion
This study suggests that the patient profile for RALP in our unit is changing, with increasing proportions of higher-stage and more advanced disease being referred and operated on. Surgical margin outcomes however have remained good.This is the author accepted manuscript. The final version is available from Wiley via http://dx.doi.org/10.1111/bju.1351
Identification of pathologically insignificant prostate cancer is not accurate in unscreened men.
BACKGROUND: Identification of men harbouring insignificant prostate cancer (PC) is important in selecting patients for active surveillance. Tools have been developed in PSA-screened populations to identify such men based on clinical and biopsy parameters. METHODS: Prospectively collected case series of 848 patients was treated with radical prostatectomy between July 2007 and October 2011 at an English tertiary care centre. Tumour volume was assessed by pathological examination. For each tool, receiver operator characteristics were calculated for predicting insignificant disease by three different criteria and the area under each curve compared. Comparison of accuracy in screened and unscreened populations was performed. RESULTS: Of 848 patients, 415 had Gleason 3+3 disease on biopsy. Of these, 32.0% had extra-prostatic extension and 50.2% were upgraded. One had positive lymph nodes. Two hundred and six (24% of cohort) were D'Amico low risk. Of these, 143 had more than two biopsy cores involved. None of the tools evaluated has adequate discriminative power in predicting insignificant tumour burden. Accuracy is low in PSA-screened and -unscreened populations. CONCLUSIONS: In our unscreened population, tools designed to identify insignificant PC are inaccurate. Detection of a wider size range of prostate tumours in the unscreened may contribute to relative inaccuracy
MRI in multiple myeloma : a pictorial review of diagnostic and post-treatment findings
Magnetic resonance imaging (MRI) is increasingly being used in the diagnostic work-up of patients with multiple myeloma. Since 2014, MRI findings are included in the new diagnostic criteria proposed by the International Myeloma Working Group. Patients with smouldering myeloma presenting with more than one unequivocal focal lesion in the bone marrow on MRI are considered having symptomatic myeloma requiring treatment, regardless of the presence of lytic bone lesions. However, bone marrow evaluation with MRI offers more than only morphological information regarding the detection of focal lesions in patients with MM. The overall performance of MRI is enhanced by applying dynamic contrast-enhanced MRI and diffusion weighted imaging sequences, providing additional functional information on bone marrow vascularization and cellularity. This pictorial review provides an overview of the most important imaging findings in patients with monoclonal gammopathy of undetermined significance, smouldering myeloma and multiple myeloma, by performing a 'total' MRI investigation with implications for the diagnosis, staging and response assessment. Main message aEuro cent Conventional MRI diagnoses multiple myeloma by assessing the infiltration pattern. aEuro cent Dynamic contrast-enhanced MRI diagnoses multiple myeloma by assessing vascularization and perfusion. aEuro cent Diffusion weighted imaging evaluates bone marrow composition and cellularity in multiple myeloma. aEuro cent Combined morphological and functional MRI provides optimal bone marrow assessment for staging. aEuro cent Combined morphological and functional MRI is of considerable value in treatment follow-up
Congenital anomalies in low- and middle-income countries: the unborn child of global surgery.
Surgically correctable congenital anomalies cause a substantial burden of global morbidity and mortality. These anomalies disproportionately affect children in low- and middle-income countries (LMICs) due to sociocultural, economic, and structural factors that limit the accessibility and quality of pediatric surgery. While data from LMICs are sparse, available evidence suggests that the true human and financial cost of congenital anomalies is grossly underestimated and that pediatric surgery is a cost-effective intervention with the potential to avert significant premature mortality and lifelong disability
The Surgical Infection Society revised guidelines on the management of intra-abdominal infection
Background: Previous evidence-based guidelines on the management of intra-abdominal infection (IAI) were published by the Surgical Infection Society (SIS) in 1992, 2002, and 2010. At the time the most recent guideline was released, the plan was to update the guideline every five years to ensure the timeliness and appropriateness of the recommendations.
Methods: Based on the previous guidelines, the task force outlined a number of topics related to the treatment of patients with IAI and then developed key questions on these various topics. All questions were approached using general and specific literature searches, focusing on articles and other information published since 2008. These publications and additional materials published before 2008 were reviewed by the task force as a whole or by individual subgroups as to relevance to individual questions. Recommendations were developed by a process of iterative consensus, with all task force members voting to accept or reject each recommendation. Grading was based on the GRADE (Grades of Recommendation Assessment, Development, and Evaluation) system; the quality of the evidence was graded as high, moderate, or weak, and the strength of the recommendation was graded as strong or weak. Review of the document was performed by members of the SIS who were not on the task force. After responses were made to all critiques, the document was approved as an official guideline of the SIS by the Executive Council.
Results: This guideline summarizes the current recommendations developed by the task force on the treatment of patients who have IAI. Evidence-based recommendations have been made regarding risk assessment in individual patients; source control; the timing, selection, and duration of antimicrobial therapy; and suggested approaches to patients who fail initial therapy. Additional recommendations related to the treatment of pediatric patients with IAI have been included.
Summary: The current recommendations of the SIS regarding the treatment of patients with IAI are provided in this guideline
National data system on near miss and maternal death: shifting from maternal risk to public health impact in Nigeria
Imaging in breast cancer: Diffuse optics in breast cancer: detecting tumors in pre-menopausal women and monitoring neoadjuvant chemotherapy
Diffuse optical spectroscopy (DOS) and diffuse optical imaging (DOI) are non-invasive diagnostic techniques that employ near-infrared (NIR) light to quantitatively characterize the optical properties of centimeter-thick, multiple-scattering tissues. Although NIR was first applied to breast diaphanography more than 70 years ago, quantitative optical methods employing time- or frequency-domain 'photon migration' technologies have only recently been used for breast imaging. Because their performance is not limited by mammographic density, optical methods can provide new insight regarding tissue functional changes associated with the appearance, progression, and treatment of breast cancer, particularly for younger women and high-risk subjects who may not benefit from conventional imaging methods. This paper reviews the principles of diffuse optics and describes the development of broadband DOS for quantitatively measuring the optical and physiological properties of thick tissues. Clinical results are shown highlighting the sensitivity of diffuse optics to malignant breast tumors in 12 pre-menopausal subjects ranging in age from 30 to 39 years and a patient undergoing neoadjuvant chemotherapy for locally advanced breast cancer. Significant contrast was observed between normal and tumor regions of tissue for deoxy-hemoglobin (p = 0.005), oxy-hemoglobin (p = 0.002), water (p = 0.014), and lipids (p = 0.0003). Tissue hemoglobin saturation was not found to be a reliable parameter for distinguishing between tumor and normal tissues. Optical data were converted into a tissue optical index that decreased 50% within 1 week in response to neoadjuvant chemotherapy. These results suggest a potential role for diffuse optics as a bedside monitoring tool that could aid the development of new strategies for individualized patient care
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