158 research outputs found

    Aspergillus niger genome-wide analysis reveals a large number of novel alpha-glucan acting enzymes with unexpected expression profiles

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    The filamentous ascomycete Aspergillus niger is well known for its ability to produce a large variety of enzymes for the degradation of plant polysaccharide material. A major carbon and energy source for this soil fungus is starch, which can be degraded by the concerted action of α-amylase, glucoamylase and α-glucosidase enzymes, members of the glycoside hydrolase (GH) families 13, 15 and 31, respectively. In this study we have combined analysis of the genome sequence of A. niger CBS 513.88 with microarray experiments to identify novel enzymes from these families and to predict their physiological functions. We have identified 17 previously unknown family GH13, 15 and 31 enzymes in the A. niger genome, all of which have orthologues in other aspergilli. Only two of the newly identified enzymes, a putative α-glucosidase (AgdB) and an α-amylase (AmyC), were predicted to play a role in starch degradation. The expression of the majority of the genes identified was not induced by maltose as carbon source, and not dependent on the presence of AmyR, the transcriptional regulator for starch degrading enzymes. The possible physiological functions of the other predicted family GH13, GH15 and GH31 enzymes, including intracellular enzymes and cell wall associated proteins, in alternative α-glucan modifying processes are discussed

    Dilemmas concerning heart procurement in controlled donation after circulatory death

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    With an expanding population at risk for heart failure and the resulting increase in patients admitted to the waiting list for heart transplantation, the demand of viable organs exceeds the supply of suitable donor hearts. Use of hearts after circulatory death has reduced this deficit. Two primary techniques for heart procurement in circulatory death donors have been described: direct procurement and perfusion and thoraco-abdominal normothermic regional perfusion. While the former has been accepted as an option for heart procurement in circulatory death donors, the latter technique has raised some ethical questions in relation to the dead donor rule. In this paper we discuss the current dilemmas regarding these heart procurement protocols in circulatory death donors.</p

    Waiting list mortality and the potential of donation after circulatory death heart transplantations in the Netherlands

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    BACKGROUND: With more patients qualifying for heart transplantation (HT) and fewer hearts being transplanted, it is vital to look for other options. To date, only organs from brain-dead donors have been used for HT in the Netherlands. We investigated waiting list mortality in all Dutch HT centres and the potential of donation after circulatory death (DCD) HT in the Netherlands. METHODS: Two different cohorts were evaluated. One cohort was defined as patients who were newly listed or were already on the waiting list for HT between January 2013 and December 2017. Follow-up continued until September 2018 and waiting list mortality was calculated. A second cohort of all DCD donors in the Netherlands (lung, liver, kidney and pancreas) between January 2013 and December 2017 was used to calculate the potential of DCD HT. RESULTS: Out of 395 patients on the waiting list for HT, 196 (50%) received transplants after a median waiting time of 2.6 years. In total, 15% died while on the waiting list before a suitable donor heart became available. We identified 1006 DCD donors. After applying exclusion criteria and an age limit of 50 years, 122 potential heart donors remained. This number increased to 220 when the age limit was extended to 57 years. CONCLUSION: Waiting list mortality in the Netherlands is high. HT using organs from DCD donors has great potential in the Netherlands and could lead to a reduction in waiting list mortality. Cardiac screening will eventually determine the true potential

    In Vivo and Ex Vivo Mitochondrial Function in COVID-19 Patients on the Intensive Care Unit

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    Mitochondrial dysfunction has been linked to disease progression in COVID-19 patients. This observational pilot study aimed to assess mitochondrial function in COVID-19 patients at intensive care unit (ICU) admission (T1), seven days thereafter (T2), and in healthy controls and a general anesthesia group. Measurements consisted of in vivo mitochondrial oxygenation and oxygen consumption, in vitro assessment of mitochondrial respiration in platelet-rich plasma (PRP) and peripheral blood mononuclear cells (PBMCs), and the ex vivo quantity of circulating cell-free mitochondrial DNA (mtDNA). The median mitoVO(2) of COVID-19 patients on T1 and T2 was similar and tended to be lower than the mitoVO(2) in the healthy controls, whilst the mitoVO(2) in the general anesthesia group was significantly lower than that of all other groups. Basal platelet (PLT) respiration did not differ substantially between the measurements. PBMC basal respiration was increased by approximately 80% in the T1 group when contrasted to T2 and the healthy controls. Cell-free mtDNA was eight times higher in the COVID-T1 samples when compared to the healthy controls samples. In the COVID-T2 samples, mtDNA was twofold lower when compared to the COVID-T1 samples. mtDNA levels were increased in COVID-19 patients but were not associated with decreased mitochondrial O(2) consumption in vivo in the skin, and ex vivo in PLT or PBMC. This suggests the presence of increased metabolism and mitochondrial damage

    Minimally invasive surgery or stenting for left anterior descending artery disease - meta-analysis

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    Minimally invasive direct coronary artery bypass (MIDCAB) surgery and percutaneous coronary intervention (PCI) are both well-established minimally invasive revascularization strategies in patients with proximal left anterior descending (LAD) lesions. We aimed to evaluate the 20-years' experience by performing a systematic review and meta-analysis comparing MIDCAB versus PCI in adults with proximal LAD disease. We searched MEDLINE, EMBASE and Cochrane on October 1st, 2021 for articles published in the year 2000 or later. The primary outcome was all-cause mortality. Secondary outcomes included cardiac mortality, repeat target vessel revascularization (rTVR), myocardial infarction (MI), and cerebrovascular accident (CVA). Outcomes were analysed at short-term, mid-term, and long-term follow-up. Random effects meta-analyses were performed. Events were compared using risk ratios (RR) with 95% confidence intervals (CI). Our search yielded 17 studies pooling 3847 patients. At short-term follow-up, cardiac mortality was higher with MIDCAB than with PCI (RR 7.30, 95% CI: 1.38 to 38.61). At long-term follow-up, MIDCAB showed a decrease in all-cause mortality (RR 0.66, 95% CI: 0.46 to 0.93). MIDCAB showed a decrease in rTVR at mid-term follow-up (RR 0.16, 95% CI: 0.11 to 0.23) and at long-term follow-up (RR 0.25, 95% CI: 0.17 to 0.38). MI and CVA comparisons were not significant. In conclusion, in patients with proximal LAD lesions, MIDCAB showed a higher short-term mortality in the RCTs, but the cohort studies suggested a lower all-cause mortality at long-term follow-up. We confirm a decreased rTVR at mid-term follow-up in the RCTs and long-term follow-up in the cohort studies

    Whole Body CT Imaging in Deceased Donor Screening for Malignancies

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    Background. In most western countries, the median donor age is increasing. The incidence of malignancies in older populations is increasing as well. To prevent donor-derived malignancies we evaluated radiologic donor screening in a retrospective donor cohort. Methods. This study analyzes the efficacy of a preoperative computed tomography (CT) scan on detecting malignancies. All deceased organ donors in the Netherlands between January 2013 and December 2017 were included. Donor reports were analyzed to identify malignancies detected before or during organ procurement. Findings between donor screening with or without CT-scan were compared. Results. Chest or abdominal CT-scans were performed in 17% and 18% of the 1644 reported donors respectively. Screening by chest CT-scan versus radiograph resulted in 1.5% and 0.0% detected thoracic malignancies respectively. During procurement no thoracic malignancies were found in patients screened by chest CT compared with 0.2% malignancies in the radiograph group. Screening by abdominal CT-scan resulted in 0.0% malignancies, compared with 0.2% in the abdominal ultrasound group. During procurement 1.0% and 1.3% malignancies were found in the abdominal CT-scan and ultrasound groups, respectively. Conclusions. Screening by CT-scan decreased the perioperative detection of tumors by 30%. A preoperative CT-scan may be helpful by providing additional information on (aberrant) anatomy to the procuring or transplanting surgeon. In conclusion, donor screening by CT-scan could decrease the risk of donor-derived malignancies and prevents unnecessary procurements per year in the Netherlands

    Gonadal function in males after chemotherapy for early-stage Hodgkin's lymphoma treated in four subsequent trials by the European Organisation for Research and Treatment of Cancer: EORTC Lymphoma Group and the Groupe d'Etude des Lymphomes de l'Adulte.

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    Contains fulltext : 51705.pdf (publisher's version ) (Open Access)PURPOSE: To analyze fertility in male patients treated with various combinations of radiotherapy and chemotherapy, with or without alkylating agents, or with radiotherapy alone for Hodgkin's lymphoma. PATIENTS AND METHODS: Follicle-stimulating hormone (FSH) levels were measured in patients with early-stage upper-diaphragmatic disease enrolled in four European Organisation for Research and Treatment of Cancer (EORTC) trials (H6-H9). Median follow-up after therapy was 32 months. Patients with FSH measurement at least 12 months after end of treatment (n = 355) were selected to assess post-treatment fertility. Patients with FSH measurement 0 to 9 months after therapy (n = 349) were selected to analyze fertility recovery; of these, patients with elevated FSH (> 10 U/L; n = 101) were followed until recovery. Factors predictive for therapy-related infertility were assessed by logistic regression. RESULTS: The proportion of elevated FSH was 3% and 8% in patients treated with radiotherapy only or with nonalkylating chemotherapy (doxorubicin, bleomycin, vinblastine, dacarbazine [ABVD], epirubicin, bleomycin, vinblastine, prednisone [EBVP]); it was 60% (P < .001) after chemotherapy containing alkylating agents (mechlorethamine, vincristine, procarbazine, prednisone [MOPP], MOPP/doxorubicin, bleomycin, vinblastine [ABV], bleomycin, etoposide, doxorubicin, cyclophosphamide, vincristine, procarbazine, prednisone [BEACOPP]). After a median time of 19 months, recovery of fertility occurred in 82% of patients treated without alkylating chemotherapy. This proportion was 30%, statistically (P < .001) lower in those treated with alkylating chemotherapy, and median time to recovery was 27 months. The post-treatment proportion of elevated FSH increased significantly (P < .001) with the dose of alkylating chemotherapy administered, and recovery was less frequent and slower after higher doses. Age more than 50 years and stage II disease also contributed to poor outcome. CONCLUSION: Fertility can be secured after nonalkylating chemotherapy for Hodgkin's lymphoma. In contrast, alkylating chemotherapy has a dismal effect, even after a limited number of cycles

    Listing criteria for heart transplantation in the Netherlands

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    The updated listing criteria for heart transplantation are presented on behalf of the three heart transplant centres in the Netherlands. Given the shortage of donor hearts, selection of those patients who may expect to have the greatest benefit from a scarce societal resource in terms of life expectancy and quality of life is inevitable. The indication for heart transplantation includes end-stage heart disease not remediable by more conservative measures, accompanied by severe physical limitation while on optimal medical therapy, including ICD/CRT‑D. Assessment of this condition requires cardiopulmonary stress testing, prognostic stratification and invasive haemodynamic measurements. Timely referral to a tertiary centre is essential for an optimal outcome. Chronic mechanical circulatory support is being used more and more as an alternative to heart transplantation and to bridge the progressively longer waiting time for heart transplantation and, thus, has become an important treatment option for patients with advanced heart failure

    Sublingual microcirculatory blood flow and vessel density in Sherpas at high altitude

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    Anecdotal reports suggest that Sherpa highlanders demonstrate extraordinary tolerance to hypoxia at high altitude despite exhibiting a lower arterial oxygen content than acclimatised Lowlanders. This study tested the hypothesis that Sherpas exposed to hypobaric hypoxia on ascent to 5300m, develop increased microcirculatory blood flow as a means of maintaining normal tissue oxygen delivery. Images of the sublingual microcirculation were obtained from 64 Sherpas and 69 Lowlanders using incident dark field imaging. Serial measurements were obtained from participants undertaking an ascent from baseline testing (35m or 1300m) to Everest base camp (5300m), and following subsequent descent in Kathmandu (1300m). Microcirculatory flow index and heterogeneity index were used to provide indices of microcirculatory flow, whilst capillary density was assessed using small vessel density. Sherpas, when compared to Lowlanders, demonstrated significantly greater microcirculatory blood flow at Everest Base Camp, but not at baseline testing or on return in Kathmandu. Additionally, Sherpa blood flow exhibited greater homogeneity at 5300m and 1300m (descent) when compared to Lowlanders. Sublingual small vessel density was not different between the two cohorts at baseline testing or at 1300m, however at 5300m Sherpas capillary density was up to 30% greater. These data suggest that Sherpas have the ability to maintain a significantly greater microcirculatory flow per unit time, and flow per unit volume of tissue at high altitude, when compared to Lowlanders. These findings support the notion that peripheral vascular factors at the microcirculatory level may be important in the process of adaptation to hypoxia

    Sarcoma of the Heart Treated with Stereotactic MR-Guided Online Adaptive Radiation Therapy

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    We present the first case in the literature of a patient with a histology-proven intimal sarcoma of the heart, recurrent after surgery, treated with stereotactic MR-guided online adaptive radiation therapy on an MR-Linac machine. The treatment was feasible and well tolerated. The CT scan 6 months after the last treatment showed stable disease
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