Recently formed Antarctic lakes host less diverse benthic bacterial and diatom communities than their older counterparts.

Glacier recession is creating new water bodies in proglacial forelands worldwide, including Antarctica. Yet, it is unknown how microbial communities of recently formed "young" waterbodies (originating decades to a few centuries ago) compare with established "old" counterparts (millennia ago). Here, we compared benthic microbial communities of different lake types on James Ross Island, Antarctic Peninsula, using 16S rDNA metabarcoding and light microscopy to explore bacterial and diatom communities, respectively. We found that the older lakes host significantly more diverse bacterial and diatom communities compared to the young ones. To identify potential mechanisms for these differences, linear models and dbRDA analyses suggested combinations of water temperature, pH, and conductivity to be the most important factors for diversity and community structuring, while differences in geomorphological and hydrological stability, though more difficult to quantify, are likely also influential. These results, along with an indicator species analysis, suggest that physical and chemical constraints associated with individual lakes histories are likely more influential to the assembly of the benthic microbial communities than lake age alone. Collectively, these results improve our understanding of microbial community drivers in Antarctic freshwaters, and help predict how the microbial landscape may shift with future habitat creation within a changing environment.

Angioplasty of Dysfunctional Dialysis Fistula or Graft with Resveratrol-Excipient and Paclitaxel-Coated Balloon Improves Primary Patency Rates Compared to Plain Angioplasty Alone.

In this prospective randomized single-blinded study (reg. ISRCTN11414306), 76 patients with a dysfunctional dialysis fistula or graft due to a single de novo or recurrent stenosis in the access circuit were randomized to receive either conventional PTA (POBA) as a standard of care (n = 38) or PTA + adjunctive PTA with a drug-coated (paclitaxel-resveratrol matrix) SeQuent® Please OTW balloon (n = 38, DCB). Patients were scheduled for follow-up PTA at 3, 6, 9, and 12 months. The time of clinically driven target-lesion reintervention rate (primary patency rate) after the index procedure was analyzed using the log-rank test. The primary patency rates at 12 months after the index procedure were 17% (DCB) vs. 11% (POBA). At 3 months, they were 87% vs. 74%, at 6 months they were 53% vs. 26%, and at 9 months they were 22% vs. 11%. The hazard ratio for DCB was 0.55 (95%CI 0.32 to 0.95). The median time needed for target-lesion reintervention was longer in the DCB group (181 days) than in the conventional PTA group (98 days, p = 0.019). We conclude that PTA with the paclitaxel-resveratrol drug-coated SeQuent® Please OTW balloon in patients with de novo or recurrent stenosis in dialysis arteriovenous fistulas or grafts prolongs the time needed for target lesion reintervention and improves primary patency rates in the first year after the index procedure.

Validation of Existing Clinical Prediction Tools for Primary Aldosteronism Subtyping.

The new clinical prediction score (SCORE) has been recently proposed for primary aldosteronism (PA) subtyping prior to adrenal vein sampling (AVS). This study aimed to compare that SCORE with previously published scores and their validation using a cohort of patients at our center who had had positive SIT confirming PA and had been diagnosed with either bilateral PA according to AVS or unilateral PA if biochemically cured after an adrenalectomy. Final diagnoses were used to evaluate the diagnostic performance of the proposed clinical prediction tools. Only Kamemura's model (with a maximum score of 4 points) and Kobayashi's score (with a maximum score of 12 points) reached 100% reliability for prediction of bilateral PA; however, with sensitivity of only 3%. On the other hand, the values of SCORE = 3 (with sensitivity of 48%), the SPACE score ≥18 (with sensitivity of 35%), the Kobayashi's score ≤2 (with sensitivity of 28%), and the Kocjan's score = 3 (with sensitivity of 28%) were able to predict unilateral PA with 100% probability. Furthermore, Umakoshi's and Young's models both reached 100% reliability for a unilateral PA with score = 4 and both predictive factors together respectively; however, the sensitivity was lower compared with previous models; 4% and 14%, respectively. None of the clinical prediction tools applied to our cohort predicted unilateral and bilateral subtypes together with the expected high diagnostic performance, and therefore can only be used for precisely defined cases.

Enhanced myometrial vascularity.

OBJECTIVE: Case report of a gynecologically polymorbid patient with enhanced myometrial vascularity, and review of current scientific literature on incidence, dia-gnostic method, and management of this phenomenon. CASE REPORT: A 38-year-old patient that has been treated long-term for secondary sterility with a medical history of laparotomic cytoreduction surgery for adenomyosis and subsequent development and treatment of postoperative intrauterine adhesions. Currently presenting with enhanced myometrial vascularity after spontaneous abortion. For symptomatic prolonged course of the observation period without tendency for spontaneous regression and risk of acute hemorrhage, she was initially indicated for selective embolization of uterine arteries and consecutive definitive treatment via hysteroscopic resection. CONCLUSION: Due to low incidence and tendency for spontaneous resorption, early recognition, and correct management of enhanced myometrial vascularity, it still represents a medical challenge.

Adrenal Venous Sampling Could Be Omitted before Surgery in Patients with Conn's Adenoma Confirmed by Computed Tomography and Higher Normal Aldosterone Concentration after Saline Infusion Test.

PURPOSE: Adrenal venous sampling (AVS) performed to distinguish unilateral and bilateral primary aldosteronism (PA) is invasive and poorly standardized. This study aimed to identify non-invasive characteristics that can select the patients with unilateral PA who could bypass AVS before surgery. METHODS: A single-center study collected a total of 450 patients with PA. Development and validation cohorts included 242 and 208 patients. The AVS was successful in 150 and 138 patients from the cohorts, and the unilateral PA was found in 96 and 94 patients, respectively. Clinical factors independently associated with lateralized AVS in multivariable logistic regression were used to construct a unilateral PA prediction score (SCORE). RESULTS: The proposed SCORE was calculated as a sum of the prevalence of adrenal nodule on computed tomography (2 points) and plasma/serum aldosterone concentration ≥ 165 ng/L after the saline infusion test (SIT) (1 point). Importantly, the SCORE = 3 points identified 48% of unilateral PA patients with a specificity of 100% in the development cohort. The zero rate of false-positive classifications was preserved with the same cut-off value in the validation cohort. CONCLUSIONS: AVS could be omitted before surgery in patients with typical Conn´s adenoma provided the aldosterone concentration ≥ 165 ng/L after the SIT.

Role of Doppler ultrasonography in the evaluation of hemodialysis arteriovenous access maturation and influencing factors.

The goal of vascular access creation is to achieve a functioning arteriovenous fistula (AVF) or arteriovenous graft (AVG). An autologous fistula has been shown to be superior to AVG or to central venous catheters (CVCs) with lowest rate of re-intervention, but vessel obstruction or immaturity accounts for 20 % to 54% of cases with primary failure of AVF. This review is focused on the factors influencing maturation; indication and timing of preoperative mapping/creation of vascular access; ultrasound parameters for creation AVF/AVG; early postoperative complications following creation of a vascular access; ultrasound determinants of fistula maturation and endovascular intervention in vascular access with maturation failure. However, vascular accesses that fail to develop, have a high incidence of correctable abnormalities, and these need to be promptly recognized by ultrasonography and managed effectively if a high success rate is to be expected. We review approaches to promoting fistula maturation and duplex ultrasonography (DUS) of evaluating vascular access maturation.

Computed tomography angiographic parameters of pulmonary artery as prognostic factors of residual pulmonary hypertension after pulmonary endarterectomy.

OBJECTIVES: This study aimed to retrospectively assess using computed tomography pulmonary angiography (CTPA) for predicting residual pulmonary hypertension (RPH) in patients with chronic thromboembolic pulmonary hypertension (CTEPH) after pulmonary endarterectomy (PEA). METHODS: We retrospectively analyzed data of 131 patients with CTEPH who underwent PEA in our center (2008-2015). We measured several diameters of the pulmonary artery and thoracic aorta preoperatively. We evaluated the relationship between these measurements (and their indices) and signs of RPH represented by pulmonary artery systolic pressure (PASP) estimated by echocardiography. RESULTS: Significant correlations were observed between the aortopulmonary index and prediction of any residual hypertension and moderate/severe hypertension 1 year after PEA, and any residual hypertension and severe hypertension 2 years after PEA. The aortopulmonary index was significantly related to a reduction in PASP 1 year after the operation. A lower aortopulmonary index (≤0.88 for the ascending aorta and ≤0.64 for the descending aorta) predicted lower RPH. CONCLUSIONS: Preoperative CTPA parameters can be used to assess the risk of RPH after PEA. The aortopulmonary index has significant predictive value for RPH and a reduction in PASP after PEA. Lower values of the aortopulmonary index suggest a better outcome after PEA.

Treatment of failing arterio-venous dialysis graft by angioplasty, stent, and stent graft: Two-years analysis of patency rates and cost-effectiveness.

The objective of this prospective randomized single-center study was to compare primary and secondary patency rates, number of percutaneous transluminal angioplasty (PTA) interventions and cost-effectiveness among PTA, deployment of a stent, or a stent graft in the treatment of failing arteriovenous dialysis grafts (AVG) due to restenosis in the venous anastomosis or the outflow vein. Altogether 60 patients with failing AVG and restenosis in the venous anastomosis or the outflow vein were randomly assigned to either PTA, placement of a stent (E-Luminexx®) or stent graft (Fluency Plus®). After the procedure, patients with stent or stent graft received dual antiplatelet therapy for the next three months. Follow-up angiography was scheduled at 3, 6, and 12 months unless requested earlier due to suspected stenosis or malfunction of the access. Subsequently, angiography was performed only if requested by the clinician. During a median follow-up of 22.4 (IQR=5.7) months patients with PTA, stent, or stent graft required 3.1±1.7, 2.5±1.7, or 1.7±2.1 (P=0.031) secondary PTA interventions. The primary patency rates were 0, 18 and 65% at 12 months and 0, 18 and 37% at 24 months in the PTA, stent, and stent graft group respectively (P<0.0001). The cost of the procedures in the first two years was €7,900±€3,300 in the PTA group, €8,500±€4,500 in the stent group, and €7,500±€6,200 in the stent graft group (P=0.45). We conclude that the treatment of failing dialysis vascular access by the deployment of a stent graft significantly improves its primary patency rates and decreases the number of secondary PTA interventions; however, the reduction in costs for maintaining AVG patency is not significant.

Hemodynamic changes in patients with extracorporeal membrane oxygenation (ECMO) demonstrated by contrast-enhanced CT examinations - implications for image acquisition technique.

Extracorporeal membrane oxygenation (ECMO) is an established tool for respiratory and circulatory support. In computed tomography, altered hemodynamics in ECMO patients requires special considerations and handling in contrast injection and its timing. In this article, we demonstrate changes in hemodynamics in ECMO patients captured on contrast-enhanced CT examinations and pitfalls in strategies for contrast injection in relation to the ECMO flow, cardiac function and the placement of ECMO cannulas. Contrast-enhanced CT of patients with ECMO requires prior knowledge of the ECMO cannulas, central venous lines, changes of hemodynamics induced by low cardiac output and the influence of adjustment of ECMO on blood flow in order to optimize injection of the contrast material and timing of the scan. Special considerations include temporary reduction of the ECMO flow, selection of the injection site and increasing volume or flow rate of the contrast material.

Heterolobosean amoebae from Arctic and Antarctic extremes: 18 novel strains of Allovahlkampfia, Vahlkampfia and Naegleria.

The diversity of heterolobosean amoebae, important members of soil, marine and freshwater microeukaryote communities in the temperate zones, is greatly under-explored in high latitudes. To address this imbalance, we studied the diversity of this group of free-living amoebae in the Arctic and the Antarctic using culture dependent methods. Eighteen strain representatives of three heterolobosean genera, Allovahlkampfia Walochnik et Mulec, 2009 (1 strain), Vahlkampfia Chatton et Lalung-Bonnaier, 1912 (2) and Naegleria Alexeieff, 1912 (15) were isolated from 179 samples of wet soil and fresh water with sediments collected in 6 localities. The Allovahkampfia strain is the first representative of the genus from the Antarctic; 14 strains (7 from the Arctic, 7 from the Antarctic) of the highly represented genus Naegleria complete the 'polar' cluster of five Naegleria species previously known from the Arctic and Sub-Antarctic regions, whereas one strain enriches the 'dobsoni' cluster of Naegleria strains of diverse origin. Present isolations of Naegleria polarisDe Jonckheere, 2006 from Svalbard, in the Arctic and Vega Island, in the Antarctic and N. neopolarisDe Jonckheere, 2006 from Svalbard and Greenland in the Arctic, and James Ross Island, the Antarctic demonstrate their bipolar distribution, which in free-living amoebae has so far only been known for Vermistella Morand et Anderson, 2007.

Arteriovenous grafts: early ultrasonography tells their fortune.

BACKGROUND: The patency of arteriovenous grafts (AVG) for hemodialysis is mostly limited by growing stenoses that lead to decreasing of blood flow, thromboses and finally to access failure. The aim of this study was to find out if detection of any pathology by duplex Doppler ultrasonography (DDU) early after creation of AVG could identify those with lower survival. METHODS: We retrospectively enrolled AVG examined by DDU in our center within 40 days after their creation during the last 10 years. The findings were divided into 4 subgroups: (1a) normal finding, (1b) DDU risk factor (low flow volume, medial calcinosis of the feeding artery, presence of intimal hyperplasia in the venous anastomosis), (2a) non-significant or (2b) significant stenosis. The primary outcome measure was the cumulative survival of people with AVGs, and the secondary was the primary (unassisted) survival. All patients underwent DDU surveillance every 3 months with pre-emptive treatment of significant stenoses. RESULTS: Overall, 340 cases were found; the median follow-up was 565 days. Normal DDU finding had 60% cases, DDU risk factor 18% cases, non-significant stenosis 13% cases and significant stenosis 9% cases. Occurrence of early significant stenosis was associated with high risk of access loss (hazards ratio (HR) 14.73; 95% CI 5.10-42.58; p < 0.0001). Similarly, the presence of a DDU risk factor and of a non-significant stenosis were related to significantly shorter access lifespan (HR 2.86; 95% CI 1.10-7.40; p = 0.03 and HR 2.83; 95% CI 1.12-7.17; p = 0.03, respectively). CONCLUSION: DDU examination of AVG early after their creation can identify those at higher risk and may contribute to individualize the surveillance strategy.

Surveillance of arteriovenous accesses with the use of duplex Doppler ultrasonography.

Stenosis is the most frequent vascular access complication and is responsible for access thrombosis and thus long-term patency limitation. Regular arteriovenous graft (AVG) examination by ultrasonography and preemptive balloon angioplasty prolong AVG cumulative patency according to some, but by far not all trials. This was why the routine use of ultrasound surveillance is not recommended recently.In this review we show huge differences in the definition of stenosis significance among the trials and other probable factors, which may have caused the contradiction of the results. Without precise definition of stenosis significance, many AVGs have been undergoing unnecessary balloon interventions with high morbidity, high cost and low benefit.

More precise diagnosis of access stenosis: ultrasonography versus angiography.

PURPOSE: Patency of mature vascular access for hemodialysis is mostly limited by the growing stenoses leading to acute access thrombosis. The therapy of choice is usually percutaneous balloon angioplasty (PTA). However, PTA injures the vessel wall and subsequent re-stenosis develops faster than de novo stenosis. Therefore, the key is in appropriate timing of PTA procedures--as late as possible but before access thrombosis develops. Ultrasonography combines the morphologic and functional access assessment, but the former is less precise than angiography. The aim of this study was to compare ultrasonographic and angiographic measuring of residual diameter as the additional criterion of significant stenoses used in our center. METHODS: Residual diameter of significant stenoses was measured by B-mode ultrasonography three times in 20 patients. All the patients were indicated for angiography and the residual diameter of the stenoses was re-analyzed by this method. The repeatability of ultrasonographic residual diameter measurements and reproducibility in comparison to angiography were expressed by coefficients of variation (CV). RESULTS: The residual diameter was 1.69 ± 0.05 mm by ultrasound and 1.65 ± 0.59 mm measured by angiography. In the ultrasound repeatability study, CV was 3.17 ± 2.76% and in the reproducibility study CV was 18.0 ± 15.6%. All the stenoses found to be significant by ultrasound were above 65% by angiography and PTA was performed. CONCLUSIONS: Ultrasonographic measurement of the residual diameter is stable in experienced hands and is well comparable to angiography results. These findings advocate residual diameter of 2.0 mm as the strong additional criterion of the significant stenoses, which can also be used in ultrasound surveillance of arteriovenous grafts.