474 research outputs found

    The effects of warming on the ecophysiology of two co-existing kelp species with contrasting distributions

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    The northeast Atlantic has warmed significantly since the early 1980s, leading to shifts in species distributions and changes in the structure and functioning of communities and ecosystems. This study investigated the effects of increased temperature on two co-existing habitat-forming kelps: Laminaria digitata, a northern boreal species, and Laminaria ochroleuca, a southern Lusitanian species, to shed light on mechanisms underpinning responses of trailing and leading edge populations to warming. Kelp sporophytes collected from southwest United Kingdom were maintained under 3 treatments: ambient temperature (12 °C), +3 °C (15 °C) and +6 °C (18 °C) for 16 days. At higher temperatures, L. digitata showed a decline in growth rates and Fv/Fm, an increase in chemical defence production and a decrease in palatability. In contrast, L. ochroleuca demonstrated superior growth and photosynthesis at temperatures higher than current ambient levels, and was more heavily grazed. Whilst the observed decreased palatability of L. digitata held at higher temperatures could reduce top-down pressure on marginal populations, field observations of grazer densities suggest that this may be unimportant within the study system. Overall, our study suggests that shifts in trailing edge populations will be primarily driven by ecophysiological responses to high temperatures experienced during current and predicted thermal maxima, and although compensatory mechanisms may reduce top-down pressure on marginal populations, this is unlikely to be important within the current biogeographical context. Better understanding of the mechanisms underpinning climate-driven range shifts is important for habitat-forming species like kelps, which provide organic matter, create biogenic structure and alter environmental conditions for associated communities

    Proteases of haematophagous arthropod vectors are involved in blood-feeding, yolk formation and immunity : a review

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    Ticks, triatomines, mosquitoes and sand flies comprise a large number of haematophagous arthropods considered vectors of human infectious diseases. While consuming blood to obtain the nutrients necessary to carry on life functions, these insects can transmit pathogenic microorganisms to the vertebrate host. Among the molecules related to the blood-feeding habit, proteases play an essential role. In this review, we provide a panorama of proteases from arthropod vectors involved in haematophagy, in digestion, in egg development and in immunity. As these molecules act in central biological processes, proteases from haematophagous vectors of infectious diseases may influence vector competence to transmit pathogens to their prey, and thus could be valuable targets for vectorial control

    COVID-19-Related Outcomes in Primary Mitochondrial Diseases: An International Study

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    OBJECTIVES: To identify factors associated with severe COVID-19, defined by hospitalization status, in patients with primary mitochondrial diseases (PMDs), thereby enabling future risk stratification and informed management decisions. METHODS: We undertook a cross-sectional, international, registry-based study. Data was extracted from the "International Neuromuscular COVID-19 Database" and collected between 1st May 2020 and 31st May 2021. The database included subjects with: 1) PMD diagnosis (any age), clinically/histopathologically suspected and/or genetically confirmed; and (2) COVID-19 diagnosis classified as "confirmed", "probable", or "suspected" based on World Health Organization definitions. The primary outcome was hospitalization due to COVID-19. We collected demographic information, smoking status, coexisting comorbidities, outcome following COVID-19 infection, and PMD genotype-phenotype. Baseline status was assessed using the modified Rankin scale (mRS) and the Newcastle Mitochondrial Disease Adult Scale (NMDAS). RESULTS: Seventy-nine subjects with PMDs from 10 countries were included (mean age 41.5±18 years): 25 (32%) were hospitalized; 48 (61%) recovered fully; 28 (35%) improved with sequelae; and three (4%) died. Statistically significant differences in hospitalization status were observed in: baseline status, including NMDAS score (p=0.003) and mRS (p=0.001); presence of respiratory dysfunction (p<0.001), neurologic involvement (p=0.003); and more than four comorbidities (p=0.002). In multivariable analysis, respiratory dysfunction was independently associated with COVID-19 hospitalization (OR, 7.66; 95%CI, 2 to 28; p=0.002). DISCUSSION: Respiratory dysfunction is an independent risk factor for severe COVID-19 in PMDs, while high disease burden and coexisting comorbidities contribute towards COVID-19 related hospitalization. These findings will enable risk stratification and informed management decisions for this vulnerable population

    Prognostic model to predict postoperative acute kidney injury in patients undergoing major gastrointestinal surgery based on a national prospective observational cohort study.

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    Background: Acute illness, existing co-morbidities and surgical stress response can all contribute to postoperative acute kidney injury (AKI) in patients undergoing major gastrointestinal surgery. The aim of this study was prospectively to develop a pragmatic prognostic model to stratify patients according to risk of developing AKI after major gastrointestinal surgery. Methods: This prospective multicentre cohort study included consecutive adults undergoing elective or emergency gastrointestinal resection, liver resection or stoma reversal in 2-week blocks over a continuous 3-month period. The primary outcome was the rate of AKI within 7 days of surgery. Bootstrap stability was used to select clinically plausible risk factors into the model. Internal model validation was carried out by bootstrap validation. Results: A total of 4544 patients were included across 173 centres in the UK and Ireland. The overall rate of AKI was 14·2 per cent (646 of 4544) and the 30-day mortality rate was 1·8 per cent (84 of 4544). Stage 1 AKI was significantly associated with 30-day mortality (unadjusted odds ratio 7·61, 95 per cent c.i. 4·49 to 12·90; P < 0·001), with increasing odds of death with each AKI stage. Six variables were selected for inclusion in the prognostic model: age, sex, ASA grade, preoperative estimated glomerular filtration rate, planned open surgery and preoperative use of either an angiotensin-converting enzyme inhibitor or an angiotensin receptor blocker. Internal validation demonstrated good model discrimination (c-statistic 0·65). Discussion: Following major gastrointestinal surgery, AKI occurred in one in seven patients. This preoperative prognostic model identified patients at high risk of postoperative AKI. Validation in an independent data set is required to ensure generalizability

    Critical Early Roles for col27a1a and col27a1b in Zebrafish Notochord Morphogenesis, Vertebral Mineralization and Post-embryonic Axial Growth

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    Fibrillar collagens are well known for their links to human diseases, with which all have been associated except for the two most recently identified fibrillar collagens, type XXIV collagen and type XXVII collagen. To assess functions and potential disease phenotypes of type XXVII collagen, we examined its roles in zebrafish embryonic and post-embryonic development.We identified two type XXVII collagen genes in zebrafish, col27a1a and col27a1b. Both col27a1a and col27a1b were expressed in notochord and cartilage in the embryo and early larva. To determine sites of type XXVII collagen function, col27a1a and col27a1b were knocked down using morpholino antisense oligonucleotides. Knockdown of col27a1a singly or in conjunction with col27a1b resulted in curvature of the notochord at early stages and formation of scoliotic curves as well as dysmorphic vertebrae at later stages. These defects were accompanied by abnormal distributions of cells and protein localization in the notochord, as visualized by transmission electron microscopy, as well as delayed vertebral mineralization as detected histologically.Together, our findings indicate a key role for type XXVII collagen in notochord morphogenesis and axial skeletogenesis and suggest a possible human disease phenotype

    Adults with RRM2B-related mitochondrial disease have distinct clinical and molecular characteristics.

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    Mutations in the nuclear-encoded mitochondrial maintenance gene RRM2B are an important cause of familial mitochondrial disease in both adults and children and represent the third most common cause of multiple mitochondrial DNA deletions in adults, following POLG [polymerase (DNA directed), gamma] and PEO1 (now called C10ORF2, encoding the Twinkle helicase) mutations. However, the clinico-pathological and molecular features of adults with RRM2B-related disease have not been clearly defined. In this multicentre study of 26 adult patients from 22 independent families, including five additional cases published in the literature, we show that extra-ocular neurological complications are common in adults with genetically confirmed RRM2B mutations. We also demonstrate a clear correlation between the clinical phenotype and the underlying genetic defect. Myopathy was a prominent manifestation, followed by bulbar dysfunction and fatigue. Sensorineural hearing loss and gastrointestinal disturbance were also important findings. Severe multisystem neurological disease was associated with recessively inherited compound heterozygous mutations with a mean age of disease onset at 7 years. Dominantly inherited heterozygous mutations were associated with a milder predominantly myopathic phenotype with a later mean age of disease onset at 46 years. Skeletal muscle biopsies revealed subsarcolemmal accumulation of mitochondria and/or cytochrome c oxidase-deficient fibres. Multiple mitochondrial DNA deletions were universally present in patients who underwent a muscle biopsy. We identified 18 different heterozygous RRM2B mutations within our cohort of patients, including five novel mutations that have not previously been reported. Despite marked clinical overlap between the mitochondrial maintenance genes, key clinical features such as bulbar dysfunction, hearing loss and gastrointestinal disturbance should help prioritize genetic testing towards RRM2B analysis, and sequencing of the gene may preclude performance of a muscle biopsy

    Outcomes after urgent thyroidectomy following rapid control of thyrotoxicosis in Graves’ disease are similar to those after elective surgery in well-controlled disease

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    Background Surgery for Graves’ disease (GD) is usually performed after adequate control with medical treatment. Occasionally, rapid pre-operative optimization is required. The primary objective was to compare the outcomes of patients undergoing elective surgery for well-controlled GD with those undergoing rapid pre-operative treatment. We also propose a formal treatment protocol for future use. Methods A retrospective cohort study in a tertiary referral centre included 247 patients with well-controlled GD undergoing elective surgery and 19 patients with poorly controlled disease undergoing surgery after rapid optimization. The latter group did not respond well to thionamides (carbimazole and/or propylthiouracil) or had intolerance or side effects to thionamides and were treated with a range of non-thionamide drugs, including Lugol’s iodine, cholestyramine, beta blockers and steroids (with or without thionamides), and closely monitored for 1–2 weeks before surgery. Outcome measures included thyroid storm, hypoparathyroidism and recurrent laryngeal nerve palsy. Results In total, 266 patients with male-to-female ratio of 1:6 and median (interquartile range) age of 39 (31–51) were included. Overall, long-term recurrent laryngeal palsy and hypoparathyroidism occurred in 1 (0.38%) and 13 (4.9%) patients, respectively. No patient had thyroid storm. There was no significant difference in hypoparathyroidism (p = 1), vocal cord palsy (p = 0.803) and post-operative bleeding (p = 0.362), between elective surgery and rapid optimization groups. Conclusion Rapid pre-operative treatment is effective, safe and is associated with similar outcomes compared to usual treatment. A rapid pre-operative optimization protocol is proposed

    Magnitude of potentially inappropriate prescribing in Germany among older patients with generalized anxiety disorder

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    <p>Abstract</p> <p>Background</p> <p>Several medications commonly used to treat generalized anxiety disorder (GAD) have been designated "potentially inappropriate" for use in patients aged ≥65 years because their risks may outweigh their potential benefits. The actual extent of use of these agents in clinical practice is unknown, however.</p> <p>Methods</p> <p>Using a database with information from encounters with general practitioners (GP) in Germany, we identified all patients, aged ≥65 years, with any GP office visits or dispensed prescriptions with a diagnosis of GAD (ICD-10 diagnosis code F41.1) between 10/1/2003 and 9/30/2004 ("GAD patients"). Among GAD-related medications (including benzodiazepines, tricyclic antidepressants [TCAs], selective serotonin reuptake inhibitors, venlafaxine, hydroxyzine, buspirone, pregabalin, and trifluoperazine), long-acting benzodiazepines, selected short-acting benzodiazepines at relatively high dosages, selected TCAs, and hydroxyzine were designated "potentially inappropriate" for use in patients aged ≥ 65 years, based on published criteria.</p> <p>Results</p> <p>A total of 975 elderly patients with GAD were identified. Mean age was 75 years, and 72% were women; 29% had diagnoses of comorbid depression. Forty percent of study subjects received potentially inappropriate agents – most commonly, bromazepam (10% of all subjects), diazepam (9%), doxepin (7%), amitriptyline (5%), and lorazepam (5%). Twenty-three percent of study subjects received long-acting benzodiazepines, 10% received short-acting benzodiazepines at relatively high doses, and 12% received TCAs designated as potentially inappropriate.</p> <p>Conclusion</p> <p>GPs in Germany often prescribe medications that have been designated as potentially inappropriate to their elderly patients with GAD – especially those with comorbid depressive disorders. Further research is needed to ascertain whether there are specific subgoups of elderly patients with GAD for whom the benefits of these medications outweigh their risks.</p
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