157 research outputs found

    High-severity wildfire leads to multi-decadal impacts on soil biogeochemistry in mixed-conifer forests.

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    During the past century, systematic wildfire suppression has decreased fire frequency and increased fire severity in the western United States of America. While this has resulted in large ecological changes aboveground such as altered tree species composition and increased forest density, little is known about the long-term, belowground implications of altered, ecologically novel, fire regimes, especially on soil biological processes. To better understand the long-term implications of ecologically novel, high-severity fire, we used a 44-yr high-severity fire chronosequence in the Sierra Nevada where forests were historically adapted to frequent, low-severity fire, but were fire suppressed for at least 70 yr. High-severity fire in the Sierra Nevada resulted in a long-term (44 +yr) decrease (>50%, P < 0.05) in soil extracellular enzyme activities, basal microbial respiration (56-72%, P < 0.05), and organic carbon (>50%, P < 0.05) in the upper 5 cm compared to sites that had not been burned for at least 115 yr. However, nitrogen (N) processes were only affected in the most recent fire site (4 yr post-fire). Net nitrification increased by over 600% in the most recent fire site (P < 0.001), but returned to similar levels as the unburned control in the 13-yr site. Contrary to previous studies, we did not find a consistent effect of plant cover type on soil biogeochemical processes in mid-successional (10-50 yr) forest soils. Rather, the 44-yr reduction in soil organic carbon (C) quantity correlated positively with dampened C cycling processes. Our results show the drastic and long-term implication of ecologically novel, high-severity fire on soil biogeochemistry and underscore the need for long-term fire ecological experiments

    Lignin/Carbohydrate Complex Isolated from Posidonia oceanica Sea Balls (Egagropili): Characterization and Antioxidant Reinforcement of Protein-Based Films

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    A lignin fraction (LF) was extracted from the sea balls of Posidonia oceanica (egagropili) and extensively dialyzed and characterized by FT-IR and NMR analyses. LF resulted water soluble and exhibited a brownish-to-black color with the highest absorbance in the range of 250-400 nm, attributed to the chromophore functional groups present in the phenylpropane-based polymer. LF high-performance size exclusion chromatography analysis showed a highly represented (98.77%) species of 34.75 kDa molecular weight with a polydispersity index of 1.10 and an intrinsic viscosity of 0.15. Quantitative analysis of carbohydrates indicated that they represented 28.3% of the dry weight of the untreated egagropili fibers and 72.5% of that of LF. In particular, eight different monosaccharides were detected (fucose, arabinose, rhamnose, galactose, glucose, xylose, glucosamine and glucuronic acid), glucuronic acid (46.6%) and rhamnose (29.6%) being the most present monosaccharides in the LF. Almost all the phenol content of LF (113.85 ± 5.87 mg gallic acid eq/g of extract) was water soluble, whereas around 22% of it consisted of flavonoids and only 10% of the flavonoids consisted of anthocyanins. Therefore, LF isolated from egagropili lignocellulosic material could be defined as a water-soluble lignin/carbohydrate complex (LCC) formed by a phenol polymeric chain covalently bound to hemicellulose fragments. LCC exhibited a remarkable antioxidant activity that remained quite stable during 6 months and could be easily incorporated into a protein-based film and released from the latter overtime. These findings suggest egagropili LCC as a suitable candidate as an antioxidant additive for the reinforcement of packaging of foods with high susceptibility to be deteriorated in aerobic conditions

    Oncological outcomes in fertility-sparing treatment in stage IA-G2 endometrial cancer

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    Background: The gold standard treatment for early-stage endometrial cancer (EC) is hysterectomy with bilateral salpingo-oophorectomy (BSO) with lymphadenectomy. In selected patients desiring pregnancy, fertility-sparing treatment (FST) can be adopted. Our review aims to collect the most incisive studies about the possibility of conservative management for patients with grade 2, stage IA EC. Different approaches can be considered beyond demolition surgery, such as local treatment with levonorgestrel-releasing intra-uterine device (LNG-IUD) plus systemic therapy with progestins. Study design: Our systematic review was performed according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) statement. PubMed, EMBASE, and Scopus databases were consulted, and five studies were chosen based on the following criteria: patients with a histological diagnosis of EC stage IA G2 in reproductive age desiring pregnancy and at least one oncological outcome evaluated. Search imputes were “endometrial cancer” AND “fertility sparing” AND “oncologic outcomes” AND “G2 or stage IA”. Results: A total of 103 patients were included and treated with a combination of LNG-IUD plus megestrol acetate (MA) or medroxyprogesterone acetate (MPA), gonadotrophin-releasing hormone (GnRH) plus MPA/MA, hysteroscopic resectoscope (HR), and dilation and curettage (D&C). There is evidence of 70% to 85% complete response after second-round therapy prolongation to 12 months. Conclusions: Conservative measures must be considered temporary to allow pregnancy and subsequently perform specific counseling to adopt surgery. Fertility-sparing management is not the current standard of care for young women with EC. It can be employed for patients with early-stage diseases motivated to maintain reproductive function. Indeed, the results are encouraging, but the sample size must be increased

    Human amniotic membrane for myocutaneous dehiscence after a radical surgical treatment of vulvar cancer: A case report

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    Background: The application of the amniotic membrane could have a favourable effect on tissue repair and regeneration. We report the first case of implant of an amniotic membrane in a patient affected by myo-cutaneous dehiscence, after a radical surgical treatment for vulvar cancer. Methods: We describe a case of a 74-years-old patient affected by vulvar cancer. After radiotherapy, the patient underwent to an anterior pelvic exenteration with uretero-ileo-cutaneostomy by Wallace, bilateral pelvic lymphadenectomy, omental biopsies, omental flap, bilateral inguinal lymphadenectomy, resection of ulcerated left inguinal lesion, reconstruction with left gracilis muscle flap and locoregional V-Y advancement flap. The patient developed a myo-cutaneous dehiscence. Two months after the surgery, following an accurate curettage of the wound and negative pressure therapy, a patch of human amniotic membrane was implanted. Results: The surgical procedure was easy, feasible and did not require long operating room times. No intraoperative or postoperative complications occurred. The results obtained were encouraging with a marked improvement in the surgical wound. Conclusion: the use of amniotic membranes was safely and easily performed to promote the healing of complicated surgical wounds

    Development of a Novel Echocardiography Ramp Test for Speed Optimization and Diagnosis of Device Thrombosis in Continuous-Flow Left Ventricular Assist Devices The Columbia Ramp Study

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    ObjectivesThis study sought to develop a novel approach to optimizing continuous-flow left ventricular assist device (CF-LVAD) function and diagnosing device malfunctions.BackgroundIn CF-LVAD patients, the dynamic interaction of device speed, left and right ventricular decompression, and valve function can be assessed during an echocardiography-monitored speed ramp test.MethodsWe devised a unique ramp test protocol to be routinely used at the time of discharge for speed optimization and/or if device malfunction was suspected. The patient's left ventricular end-diastolic dimension, frequency of aortic valve opening, valvular insufficiency, blood pressure, and CF-LVAD parameters were recorded in increments of 400 rpm from 8,000 rpm to 12,000 rpm. The results of the speed designations were plotted, and linear function slopes for left ventricular end-diastolic dimension, pulsatility index, and power were calculated.ResultsFifty-two ramp tests for 39 patients were prospectively collected and analyzed. Twenty-eight ramp tests were performed for speed optimization, and speed was changed in 17 (61%) with a mean absolute value adjustment of 424 ± 211 rpm. Seventeen patients had ramp tests performed for suspected device thrombosis, and 10 tests were suspicious for device thrombosis; these patients were then treated with intensified anticoagulation and/or device exchange/emergent transplantation. Device thrombosis was confirmed in 8 of 10 cases at the time of emergent device exchange or transplantation. All patients with device thrombosis, but none of the remaining patients had a left ventricular end-diastolic dimension slope >−0.16.ConclusionsRamp tests facilitate optimal speed changes and device malfunction detection and may be used to monitor the effects of therapeutic interventions and need for surgical intervention in CF-LVAD patients

    The species diversity × fire severity relationship is hump-shaped in semiarid yellow pine and mixed conifer forests

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    The combination of direct human influences and the effects of climate change are resulting in altered ecological disturbance regimes, and this is especially the case for wildfires. Many regions that historically experienced low–moderate severity fire regimes are seeing increased area burned at high severity as a result of interactions between high fuel loads and climate warming with a number of negative ecological effects. While ecosystem impacts of altered fire regimes have been examined in the literature, little is known of the effects of changing fire regimes on forest understory plant diversity even though understory taxa comprise the vast majority of forest plant species and play vital roles in overall ecosystem function. We examined understory plant diversity across gradients of wildfire severity in eight large wildfires in yellow pine and mixed conifer temperate forests of the Sierra Nevada, California, USA. We found a generally unimodal hump-shaped relationship between local (alpha) plant diversity and fire severity. High-severity burning resulted in lower local diversity as well as some homogenization of the flora at the regional scale. Fire severity class, post-fire litter cover, and annual precipitation were the best predictors of understory species diversity. Our research suggests that increases in fire severity in systems historically characterized by low and moderate severity fire may lead to plant diversity losses. These findings indicate that global patterns of increasing fire size and severity may have important implications for biodiversity

    Caveat medicus:Clinician experiences in publishing reports of serious oncology-associated adverse drug reactions

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    Oncology-associated adverse drug/device reactions can be fatal. Some clinicians who treat single patients with severe oncology-associated toxicities have researched case series and published this information. We investigated motivations and experiences of select individuals leading such efforts. Clinicians treating individual patients who developed oncology-associated serious adverse drug events were asked to participate. Inclusion criteria included having index patient information, reporting case series, and being collaborative with investigators from two National Institutes of Health funded pharmacovigilance networks. Thirty-minute interviews addressed investigational motivation, feedback from pharmaceutical manufacturers, FDA personnel, and academic leadership, and recommendations for improving pharmacovigilance. Responses were analyzed using constant comparative methods of qualitative analysis. Overall, 18 clinicians met inclusion criteria and 14 interviewees are included. Primary motivations were scientific curiosity, expressed by six clinicians. A less common theme was public health related (three clinicians). Six clinicians received feedback characterized as supportive from academic leaders, while four clinicians received feedback characterized as negative. Three clinicians reported that following the case series publication they were invited to speak at academic institutions worldwide. Responses from pharmaceutical manufacturers were characterized as negative by 12 clinicians. One clinician's wife called the post-reporting time the "Maalox month," while another clinician reported that the manufacturer collaboratively offered to identify additional cases of the toxicity. Responses from FDA employees were characterized as collaborative for two clinicians, neutral for five clinicians, unresponsive for negative by six clinicians. Three clinicians endorsed developing improved reporting mechanisms for individual physicians, while 11 clinicians endorsed safety activities that should be undertaken by persons other than a motivated clinician who personally treats a patient with a severe adverse drug/device reaction. Our study provides some of the first reports of clinician motivations and experiences with reporting serious or potentially fatal oncology-associated adverse drug or device reactions. Overall, it appears that negative feedback from pharmaceutical manufacturers and mixed feedback from the academic community and/or the FDA were reported. Big data, registries, Data Safety Monitoring Boards, and pharmacogenetic studies may facilitate improved pharmacovigilance efforts for oncology-associated adverse drug reactions. These initiatives overcome concerns related to complacency, indifference, ignorance, and system-level problems as barriers to documenting and reporting adverse drug events- barriers that have been previously reported for clinician reporting of serious adverse drug reactions

    Acute hypoxemia and vascular function in healthy humans.

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    Endothelium-dependent flow mediated dilation (FMD) and endothelium-independent dilation (GTN) are impaired at high altitude (5050 m), and FMD is impaired following acute exposure (<60-minutes) to normobaric hypoxia equivalent to ∼5050 m (∼FI O2  = 0.11). Whether glyceryl trinitrate (GTN)-induced dilation is impaired acutely, and whether FMD is impaired during milder hypoxia is unknown. Therefore, we assessed brachial FMD at baseline and following 30-minutes of mild (74 ± 2 mmHg PET O₂) and moderate (50 ± 3 mmHg PET O₂) normobaric hypoxia (n = 12) or normoxia (time-control trial; n = 10). We also assessed GTN-dilaiton following the hypoxic FMD tests and in normoxia on a separate control day (n = 8). Compared to normoxic baseline, reduction during mild and moderate hypoxic exposure were evident in FMD (mild vs moderate: -1.2 ± 1.1% vs. -3.1 ± 1.7%; P = 0.01) and GTN-dilation (-2.1 ± 1.0 vs. -4.2 ± 2.0; P = 0.01); the decline in FMD and GTN-dilation were greater during moderate hypoxia (P < 0.01). When allometrically corrected for baseline diameter and FMD shear rate under the curve (SRAUC ), relative FMD was attenuated in both conditions (mild vs moderate: 0.6 ± 0.9% vs. 0.8 ± 0.7%; P ≤ 0.01). Following 30-minutes of normoxic time-control, FMD was reduced (-0.6 ± 0.3%; P = 0.02). In summary, there was a graded impairment in FMD during mild and moderate hypoxic exposure, which appears to be influenced by shear patterns and incremental declines in smooth muscle vasodilator capacity (impaired GTN-dilation). Our findings from the normoxic controls study, suggest the decline in FMD in acute hypoxia also appears to be influenced by 30-minutes of supine rest/inactivity. This article is protected by copyright. All rights reserved
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