Significant Decrease In Rate Research Articles

Prognostic Significance of a Negative Confirmatory Biopsy on Reclassification Among Men on Active Surveillance

To examine the association between absence of disease on confirmatory biopsy and risk of pathologic reclassification in men on active surveillance (AS). Men with grade groups 1 and 2 disease on AS between 2002 and 2015 were identified who received a confirmatory biopsy within 1 year of diagnosis and ≥3 biopsies overall. The primary outcomes were pathologic reclassification by grade (any increase in primary Gleason pattern or Gleason score) or volume (>33% of sampled cores involved or increase in the number of cores with >50% involvement). The effect of a negative confirmatory biopsy survival was evaluated using Kaplan-Meier analysis and a Cox proportional hazards modeling. Out of 635 men, 224 met inclusion criteria (median follow-up: 55.8 months). A total of 111 men (49.6%) had a negative confirmatory biopsy. Decreased grade reclassification (69.7% vs 83.9%; P = .01) and volume reclassification (66.3% vs 87.4%; P = .004) was seen at 5 years for men with a negative confirmatory biopsy compared with those with a positive biopsy. On adjusted analysis, a negative confirmatory biopsy was associated with a decreased risk of grade reclassification (hazard ratio, 0.51; 95% confidence interval, 0.28-0.94; P = .03) and volume reclassification (hazard ratio, 0.32; 95% confidence interval, 0.17-0.61; P = .0006) at a median of 4.7 years. Absence of cancer on the confirmatory biopsy is associated with a significant decrease in rate of grade and volume reclassification among men on AS. This information may be used to better counsel men on AS.

Low temperature MBBR nitrification: Microbiome analysis

This study aims to investigate post carbon removal moving bed biofilm reactor (MBBR) nitrification through the transition from 20 °C to 1 °C and during through long term operation at 1 °C. Four pilot nitrifying MBBR reactors were operated at various ammonia loading rates to elucidate the temperature effects on ammonia removal rates, cell viability and bacterial communities. The transition from 20 °C to 1 °C and during long term operation at 1 °C were modeled using Arrhenius temperature correction coefficients. Specifically, the steady state removal rates at 1 °C on average were 22.8% of the maximum ammonia removal rate at 20 °C, which corresponds to an Arrhenius temperature correction of 1.086 during steady operation at 1 °C. The microbial communities of the nitrifying MBBR biofilm were shown to be significantly more diverse at 20 °C as compared to 1 °C operation. Although less diverse at 1 °C, 2000 species of bacteria were identified in the nitrifying biofilm during operation at this low temperature. Nitrosomonads were shown to be the dominant ammonia oxidizing bacteria (AOB) and Nitrospira was shown to be the dominant nitrite oxidizing bacteria (NOB) in all the pilot MBBR reactors at all temperatures. The performance of the post carbon removal nitrifying MBBR systems were shown to be enhanced at 1 °C by an increase in the viable embedded biomass as well as thicker biofilm. This effectively increases the number of viable cell present during low temperature operation, which partially compensates for the significant decrease in rate of ammonia removal per nitrifying cell. Operation at the highest loading conditions tested in this study at 1 °C were shown to reduce the ammonia removal rate compared to lower loading conditions at 1 °C. The lower performance at higher loading conditions at 1 °C demonstrated an enrichment in the stress response metagenomics pathways of the system.

Delivery Room Quality Improvement Project Improved Compliance with Best Practices for a Community NICU.

A Quality Improvement bundle was implemented with the goal of standardizing the multidisciplinary approach to delivery room management. We used a Pre-Post Quality Improvement initiative with the following aims: (1) Placement of a functioning pulse oximeter by two minutes after birth, (2) Delayed intubation, (3) Normothermia on Neonatal Intensive Care Unit Admission, (4) Use of a pre-brief, debrief, and delivery room checklist. Data was collected for 548 infants, which represents every admission to the Palomar Rady Children’s Hospital Neonatal Intensive Care Unit during the 35 month study period from January 1, 2010 to November 30, 2012. The intervention began on May 1, 2011. The objective of increasing the frequency of each goal was met. A significant decrease in rates of retinopathy of prematurity in our post-intervention group was found. Odds ratio 0.00 (0.000, 0.696) p = 0.008. However, this was not confirmed in the multivariable analysis so should be interpreted with caution. This quality improvement project had a positive effect on newborn resuscitation at Palomar Medical Center.

Simple Technique of Circular Stapled Anastomosis in Ivor Lewis Esophagectomy.

Advent of minimally-invasive esophagectomy necessitated the incorporation of stapled anastomotic techniques especially for intrathoracic anastomosis. We present our approach to the Ivor Lewis esophagectomy highlighting a simple modification in the anastomotic technique and review our experience with anastomotic outcomes. With IRB approval, patients who underwent Ivor Lewis esophagectomy with circular-stapled end-to-end anastomosis (EEA) were identified, divided into three equal sequential cohorts (A, B, and C), and compared for perioperative outcome. Cohorts were divided in a chronological order to have equal number of patients in each group. Seventy-five patients underwent Ivor Lewis esophagectomy with circular stapled (EEA-25/28) anastomosis. Group A had longer median postoperative hospital stay and median postoperative ICU stay compared to Groups B and C. Ten patients (13%) had anastomotic leak-one patient required redo-anastomosis and other patients were managed with endoscopic interventions. There was significant decrease in rate of anastomotic leak with experience (8 versus 1 versus 1, P = .004). There were two perioperative deaths, one each in Groups A and C, including one death due to anastomotic leak (Group A). Use of simple modifications to stapled EEA, as described here, has led to decrease in anastomotic leaks following Ivor Lewis esophagectomy.

Countering Vaccine Hesitancy.

Immunizations have led to a significant decrease in rates of vaccine-preventable diseases and have made a significant impact on the health of children. However, some parents express concerns about vaccine safety and the necessity of vaccines. The concerns of parents range from hesitancy about some immunizations to refusal of all vaccines. This clinical report provides information about addressing parental concerns about vaccination.

Physiological and perceptual effects of precooling in wheelchair basketball athletes

Objective: To investigate the physiological and perceptual effects of three precooling strategies during pre-exercise rest in athletes with a spinal cord injury (SCI).Design: Randomized, counterbalanced. Participants were precooled, then rested for 60 minutes (22.7 ± 0.2°C, 64.2 ± 2.6%RH).Setting: National Wheelchair Basketball Training Centre, Australia.Participants: Sixteen wheelchair basketball athletes with a SCI.Interventions: Participants were precooled through; 1) 10 minutes of 15.8°C cold water immersion (CWI), 2) ingestion of 6.8 g/kg−1 of slushie (S) from sports drink; 3) ingestion of 6.8 g/kg−1 of slushie with application of iced towels to the legs, torso and back/arms (ST); or 4) ingestion of 6.8 g/kg−1 of room temperature (22.3°C) sports drink (CON).Outcome measures: Core temperature (Tgi), skin temperature (Tsk), heart rate (HR), and thermal and gastrointestinal comfort.Results: Following CWI, a significant reduction in Tgi was observed compared to CON, with a greatest reduction of 1.58°C occurring 40 minutes post-cooling (95% CI [1.07, 2.10]). A significant reduction in Tgi following ST compared to CON was also observed at 20 minutes (0.56°C; [0.03, 1.09]) and 30 minutes (0.56°C; [0.04, 1.09]) post-cooling. Additionally, a significant interaction between impairment level and time was observed for Tgi and HR, demonstrating athletes with a higher level of impairment experienced a greater reduction in HR and significant decrease in rate of decline in Tgi, compared to lesser impaired athletes.Conclusion: CWI and ST can effectively lower body temperature in athletes with a SCI, and may assist in tolerating warm conditions.

Stillbirth and neonatal death rates across time: the influence of pregnancy terminations and birth defects in a Western Australian population-based cohort study.

BackgroundThe stillbirth rate in most high income countries reduced in the early part of the 20th century but has apparently been static over the past 2½ decades. However, there has not been any account taken of pregnancy terminations and birth defects on these trends. The current study sought to quantify these relationships using linked Western Australian administrative data for the years 1986–2010.MethodsWe analysed a retrospective, population-based cohort of Western Australia births from 1986 to 2010, with de-identified linked data from core population health datasets.ResultsThe study revealed a significant decrease in the neonatal death rate from 1986 to 2010 (6.1 to 2.1 neonatal deaths per 1000 births; p < .01), while the overall stillbirth rate remained static. The stillbirth trend was driven by deaths in the extremely preterm period (20–27 weeks; which account for about half of all recorded stillbirths and neonatal deaths), masking significant decreases in the rate of stillbirth at very preterm (28–31 weeks), moderate to late preterm (32–36 weeks), and term (37+ weeks). For singletons, birth defects made up an increasing proportion of stillbirths and decreasing proportion of neonatal deaths over the study period—a shift that appears to have been largely driven by the increase in late pregnancy terminations (20 weeks or more gestation). After accounting for pregnancy terminations, we observed a significant downward trend in stillbirth and neonatal death rates at every gestational age.ConclusionsChanges in clinical practice related to pregnancy terminations have played a substantial role in shaping stillbirth and neonatal death rates in Western Australia over the 2½ decades to 2010. The study underscores the need to disaggregate perinatal mortality data in order to support a fuller consideration of the influence of pregnancy terminations and birth defects when assessing change over time in the rates of stillbirth and neonatal death.

Can adding Ephedrine to Admixture of Propofol &amp; Lidocaine Overcome Propofol Associated Hemodynamic Changes and Injection Pain?

Purpose: There are numerous studies researching ways to alleviate propofol injection pain. In this study, we evaluated and compared the use of propofol-lidocaine admixture vs propofol-lidocaine combined with ephedrine, on vascular pain and hemodynamic changes associated propofol. Methods: This double-blinded, prospective, randomised study was performed on 100 patients with ASA I-II who were divided into two group. The first received admixture consisting of 20 mg of lidocaine and propofol 1% 20 ml (Group L), and the other received admixture consisting of 20 mcg ephedrine, 20 mg lidocaine and propofol 1% 20 ml (Group LE). Baseline and after induction heart rate, mean arterial pressure and rate pressure product (RPP) were recorded per minute. Vascular pain were evaluated with verbal rating scale. Results: Data of 40 patients in group L and 39 patients in Group LE were evaluated in the study. The incidence of pain in group L was 90%, it was 38.4% for Group LE. Mild pain was observed significantly more in Group L when compared to Group LE (p<0.05). Average blood pressure and RPP immediately after induction and 1 min after intubation were signifi cantly higher in group LE compared to group L (p<0.05). Heart rate was higher in Group LE immediately after induction and at initially 4 minutes after intubation. Conclusion: Our study has demonstrated significant decrease in rate of vascular pain and increased hemodynamic stability in patients receiving 20 mg ephedrine added to 20 ml % 1 propofol and 20 mg lidocaine admixture when compared to those who only received the lidocaine-propofol admixture.

Latitudinal variation in glacial erosion rates from Patagonia and the Antarctic Peninsula (46°S–65°S)

We use extensive sedimentary and marine geophysical data to derive sediment volume−based millennial time-scale glacial erosion rates ( Ē ) from glacially influenced fjords and bays across a broad latitudinal transect, from central Patagonia (46°S) to the Antarctic Peninsula (65°S), and to determine how glacial erosion rates change with increasing latitude and decreasing atmospheric temperatures. We also calculate million-year time-scale erosion rates for the western Antarctic Peninsula cordillera and inner continental shelf from seismic stratigraphic analysis of the continental margin. These results are complemented by erosion rates derived from existing thermochronology data sets (apatite fission-track and apatite [U-Th]/He) for both Patagonia and the Antarctic Peninsula regions. Despite considerable regional variability, our results show a clear trend of decreasing Ē with increasing latitude. Millennial Ē values span two orders of magnitude, from 0.02 mm/yr for Illiad glacier on Anvers Island, Antarctica (∼64.5°S), to 0.83 mm/yr for San Rafael glacier in northern Patagonia (∼46.5°S). Regional averages are three times higher for the Patagonian areas than the Antarctic Peninsula areas. This trend is interpreted to result from a general decrease in temperature and water availability at the ice-bedrock interface. For the Antarctic Peninsula study sites, erosion rates are highly clustered around 0.1 mm/yr, with the exception of Maxwell Bay, for which the Ē value is 0.36 mm/yr. In Patagonia, erosion rates are more variable than in the Antarctic Peninsula, with Ē ranging between 0.14 mm/yr (Europa glacier area) and 0.83 mm/yr (San Rafael glacier area). This regional variability in Ē is interpreted as due to differences in hypsometry and bedrock resistance to erosion. Million-year time-scale Ē values derived from thermochronology ages also decrease with latitude, with maximum values decreasing from ∼0.9−1.1 mm/yr north of 46°S to ∼0.1−0.2 mm/yr south of 48°S in Patagonia, and reaching ∼0.2−0.3 mm/yr in the Antarctic Peninsula. The sediment-based million-year time-scale Ē estimates for the western Antarctic Peninsula cordillera indicate that glacial erosion rates increased by 25%−30% after 5.3 Ma, from ∼0.09 mm/yr (5.3−9.5 Ma) to ∼0.11−0.12 mm/yr (<5.3 Ma). For Patagonia, the decrease in long-term erosion rates south of ∼46°S is interpreted to result from relatively long periods of slow glacial erosion associated with the ice masses having been colder (subpolar) on the southern Patagonian cordillera, and having eroded at rates comparable to those we obtained for the Antarctic Peninsula. These long-term erosion rates are 1−2 orders of magnitude lower than estimates based on recent sediment yields, highlighting the transient nature of high-sediment-flux events. However, our sediment volume−derived millennial time-scale Ē closely approximates the maximum values of tectonic time-scale Ē values derived from thermochronology ages. Our combined millennial and million-year time-scale glacial erosion data quantify the significant decrease in rates of glacially driven denudation at geological (tectonic) and millennial time scales with increasing latitude from Patagonia to the Antarctic Peninsula, highlighting the influence of climate on mountain denudation.

2,4-D and Glyphosate affect aquatic biofilm accrual, gross primary production, and community respiration

2,4-Dichlorophenoxyacetic acid (2,4-D) and glyphosate are widely used agricultural herbicides commonly found in surface waters near cultivated land. Field experiments were conducted to determine the effects of 2,4-D and glyphosate on biofilms in a pond next to agricultural land in Athabasca, Alberta. Contaminant-exposure substrates (CES) consisted of GF/C glass fiber or a cellulose filter paper substrates placed on specimen jars filled with agar that contained low levels of nitrogen and phosphorus, and different concentrations (15, 9.0, 1.5 mM) of either 2,4-D or glyphosate. Nutrients and herbicide diffused freely through the agar to the substrate surface. CES arrays were deployed 15 cm below the water surface for 22 days, after which biofilms were collected and biomass (chlorophyll a ), autotroph gross primary production (GPP), and heterotroph community respiration (CR) were measured. 2,4-D (15 mM) caused significant decreases in rates of biomass accrual (−22%), GPP (−34%), and CR(−63%). Glyphosate (15 mM) also caused significant decreases in rates of biomass accrual (−50%), GPP (−67%), and CR (−47%). For the contaminant concentrations used, mean flux rates are estimated to be between 50–700 ng cm −2 min −1 .

Percutaneous Selective Vertebroplasty: State of the Art Management in Well-Confined Metastatic Vertebral Lesions.

Study DesignProspective cohort study.PurposeTo evaluate the clinical and radiological results of percutaneous selective vertebroplasty (PSV) as first-line treatment options in the setting of well-confined spinal metastases.Overview of LiteratureRecent technological advances combined with innovative interventional techniques enable an alternative less invasive treatment option for many patients with malignant vertebral body infiltration. Percutaneous vertebral augmentation procedures offer less invasive but effective pain relief to many patients with symptomatic spinal metastatic disease.MethodsEleven patients with 21 well-confined metastatic vertebral lesions that had been treated with PSV were included. Pain was evaluated one week, one month, 3 months and 6 months post-procedure using a 10-point visual analogue scale (VAS). A statistical analysis including repeated measures analysis of variance test was used to collectively indicate the presence of any significant differences between different time sequences. Medication usage and range of mobility were also evaluated.ResultsThe 11 patients had an average age of 42 years and 54.5% were male. Highly significant improvements in VAS scores at rest and with activity (p<0.001) were evident. There was a significant decrease in rate of medication consumption post-procedure (p<0.05).ConclusionsPSV can be used successfully as the first-line treatment for well-confined metastatic vertebral lesions. It is also an effective method to decrease pain, increase mobility, and decrease narcotic administration in such patients.

The effect of a whey protein supplement dose on satiety and food intake in resistance training athletes

Objective: Many athletes perform resistance training and consume dietary protein as a strategy to promote anabolic adaptation. Due to its high satiety value, the regular addition of supplemented dietary protein could plausibly displace other key macronutrients such as carbohydrate in an athlete's diet. This effect will be influenced by the form and dose of protein. Therefore, this study assessed the impact of liquid whey protein dose manipulation on subjective sensations of appetite and food intake in a cohort of athletes. Design: Ten male athletes who performed both resistance and aerobic (endurance) training (21.2 ± 2.3 years; 181.7 ± 5.7 cm and 80.8 ± 6.1 kg) were recruited. In four counter-balanced testing sessions they consumed a manipulated whey protein supplement (20, 40, 60 or 80 g protein) 1 hour after a standardised breakfast. Subsequent energy intake was measured 3 hours after the protein supplement using an ad libitum test meal. Subjective appetite sensations were measured periodically during the test day using visual analogue scales. Results: All conditions resulted in a significant decrease in ratings of hunger (50–65%; P < 0.05) at the time of supplement consumption. However, there were no significant differences between the conditions at any time point for subjective appetite sensations or for energy consumed in the ad libitum meal: 4382 ± 1004, 4643 ± 982, 4514 ± 1112, 4177 ± 1494 kJ respectively. Conclusion: Increasing whey protein supplement dose above 20 g did not result in a measurable increase in satiety or decrease in food intake. However, the inclusion of additional whey protein supplementation where not otherwise consumed could plausibly reduce dietary intake.

In situ poly(sodium acrylate)‐based nanocomposite formation by redox‐initiated solution polymerization

Polymer‐based nanocomposites have been widely investigated as a potential method to modify polymer and biopolymer properties. Poly(sodium acrylate) (PNaA)/nanosilver nanocomposites with 0.5, 1, 2, and 3 wt% nanofiller were prepared by in situ polymerization. The free radical, redox‐initiated, aqueous solution polymerization of NaOH‐neutralized acrylic acid was conducted in the presence of nanosilver. The progress of the polymerization was monitored using gravimetric conversion measurements. The addition of 0.5 wt% nanosilver to the polymerization resulted in a significant decrease in rate of polymerization The effect on rate was noticeably reduced when the experiment was repeated with nanoclay, a nonmetallic nanofiller, in lieu of nanosilver. POLYM. ENG. SCI., 55:1230–1236, 2015. © 2015 Society of Plastics Engineers

Neuroimaging of Natalizumab Complications in Multiple Sclerosis: PML and Other Associated Entities.

Natalizumab (Tysabri) is a monoclonal antibody (α4 integrin antagonist) approved for treatment of multiple sclerosis, both for patients who fail therapy with other disease modifying agents and for patients with aggressive disease. Natalizumab is highly effective, resulting in significant decreases in rates of both relapse and disability accumulation, as well as marked decrease in MRI evidence of disease activity. As such, utilization of natalizumab is increasing, and the presentation of its associated complications is increasing accordingly. This review focuses on the clinical and neuroimaging features of the major complications associated with natalizumab therapy, focusing on the rare but devastating progressive multifocal leukoencephalopathy (PML). Associated entities including PML associated immune reconstitution inflammatory syndrome (PML-IRIS) and the emerging phenomenon of rebound of MS disease activity after natalizumab discontinuation are also discussed. Early recognition of neuroimaging features associated with these processes is critical in order to facilitate prompt diagnosis, treatment, and/or modification of therapies to improve patient outcomes.

Neurofunctional effects of quetiapine in patients with bipolar mania

Several lines of evidence suggest that abnormalities within portions of the extended limbic network involved in affective regulation and expression contribute to the neuropathophysiology of bipolar disorder. In particular, portions of the prefrontal cortex have been implicated in the appearance of manic symptomatology. The effect of atypical antipsychotics on activation of these regions, however, remains poorly understood. Twenty-two patients diagnosed with bipolar mania and 26 healthy subjects participated in a baseline functional magnetic resonance imaging scan during which they performed a continuous performance task with neutral and emotional distractors. Nineteen patients with bipolar disorder were treated for eight weeks with quetiapine monotherapy and then rescanned. Regional activity in response to emotional stimuli was compared between healthy and manic subjects at baseline; and in the subjects with bipolar disorder between baseline and eight-week scans. At baseline, functional activity did not differ between subjects with bipolar disorder and healthy subjects in any region examined. After eight weeks of treatment, subjects with bipolar disorder showed a significant decrease in ratings on the Young Mania Rating Scale (YMRS) (p < 0.001), and increased activation in the right orbitofrontal cortex (OFC) (p = 0.002); there was a significant association between increased right OFC activity and YMRS improvement (p = 0.003). These findings are consistent with suggestions that mania involves a loss of emotional modulatory activity in the prefrontal cortex--restoration of the relatively greater elevation in prefrontal activity widely observed in euthymic patients is associated with clinical improvement. It is not clear, however, whether changes are related to quetiapine treatment or represent a non-specific marker of affective change.

Classroom Rule Violations in Elementary School Students With Callous-Unemotional Traits

An emerging body of mental health research provides evidence that callous-unemotional (CU) traits explain significant and meaningful variance among children with disruptive behavior disorders. However, the classroom behavior of students with CU traits has not yet been adequately studied. This study examined this issue using teacher-recorded classroom rule violations (RVs). Participants were 648 children (346 boys; M age = 8.14) from 28 classrooms (kindergarten–sixth grade) distributed across three schools participating in a schoolwide behavioral intervention. Teachers completed rating scales approximately 4 to 6 weeks after the start of the school year, prior to initiating the schoolwide intervention. After completing ratings, teachers recorded daily frequency counts of RVs for each student in their classroom for the remainder of the school year. Growth curve modeling analyses indicated that (a) CU traits were associated with elevated rates of RVs at the start of the school year even after taking attention-deficit/hyperactivity disorder (ADHD) and oppositional defiant disorder/conduct disorder (ODD/CD) into account and (b) CU traits were associated with a significant decrease in rates of RVs across the school year. CU traits appear to explain significant and important variance in classroom RVs among elementary school age students.

Formulation, optimization and evaluation of curcumin-β-cyclodextrin-loaded sponge for effective drug delivery in thermal burns chemotherapy

The present study was designed to determine the role of curcumin-β-cyclodextrin-loaded sponge on burn wound healing in rats. Curcumin-β-cyclodextrin complex was prepared by the solvent evaporation encapsulation method. Molecular inclusion complex of curcumin-β-cyclodextrin was incorporated into gelatin sponge. The developed sponge was characterized for drug entrapment, drug release and morphology. The biological activity of optimized formulation was determined on burn wounds which were made on rats. The burn wound healing efficacy was analyzed through physical and histological changes observed at the wound sites. There was a significant decrease in rate of wound contraction in experimental groups then the control group. Curcumin-β-cyclodextrin-loaded sponge treated wound was found to heal in rate comparable to marketed formulation with no sign of adverse consequence. The result clearly substantiates the beneficial effects of curcumin-β-cyclodextrin-loaded sponge in the acceleration of wound healing.

Variation in stream organic matter processing among years and benthic habitats in response to forest clearfelling

We assessed rates of organic matter (OM) processing in coarse gravel and fine benthic sediment, along with water temperature, in four clearfell harvested and two undisturbed headwater streams flowing through wet eucalypt forest in southern Tasmania, Australia. Clearfell forestry in Tasmanian wet eucalypt forest involves felling of all timber followed by a high intensity regeneration burn to provide a receptive mineral seedbed for seedling growth. Bacterial carbon production and cellulose decomposition potential (together referred to as OM processing) were measured seasonally 3–5years before and 2–4years after harvesting in each stream. We employed a staircase design (staggered harvesting treatments) within a multiple before–after control–impact design to distinguish harvesting effects from natural variation. Clearfell harvesting raised the yearly mean water temperature by between 0.25°C and 0.94°C, and raised the maximum water temperature by between 0.84 and 1.6°C. Rates of cellulose decomposition were not significantly correlated with sediment temperature but bacterial carbon production showed weak, significant correlations with temperature in fine (r=0.20, P=0.01, n=137) and coarse gravel sediment (r=0.39, P<0.001, n=137). The response in OM processing to clearfell harvesting differed between years and among benthic habitats. In coarse gravel habitat, there was a significant decrease in rates of cellulose decomposition potential in the 2nd and 4th year after harvesting, and a significant decrease in bacterial carbon production in the 3rd year after harvesting. However, we found a significant increase in rates of bacterial carbon production of fine sediment habitat in the 2nd and 4th year after harvesting. The contrasting response of OM processing between habitats indicates that habitat-specific changes occur after clearfell harvesting, which inhibit attempts to quantitatively predict downstream cumulative effects. Scaling up the habitat-specific responses will not only require estimates of the relative abundances of the distinct habitats, but may also require research into how different spatial configurations of habitats may affect reach- and catchment-scale estimates of OM processing.

Relative extents of activity loss between enzyme–substrate interactions and combined environmental mechanisms

Enzymatic hydrolysis of biomass undergoes a significant decrease in rate, which is often attributed to activity loss of enzyme during the incubation. Activity loss due to both interaction with substrate (for example inactivation of adsorbed enzyme) and all combined environmental mechanisms in a substrate free buffer solution were compared in this study. Enzyme-substrate interactions contributed more towards the overall activity loss than did the combined environmental sources as evidenced from three independent metrics. (1) Relative extents of inactivation were higher for enzyme-substrate interactions than for environmental mechanisms. (2) Apparent half-lives (1.37-11.01 h) following interaction with substrate were relatively small compared to environmental inactivation, which was 21.5h. (3) The inactivation rate constant for enzyme-substrate interactions (0.56 h(-1)) was 46 times higher than that of environmental inactivation (0.0123 h(-1)). These results suggest enzyme-substrate interaction is the main cause of cellulase activity loss and contributes significantly to the slow rate of hydrolysis.

Paradigm Shift in the Treatment of Elderly Patients With Unresectable Stage IV Colorectal Cancer.

See Article on Page 175-181 Colorectal cancer (CRC) is one of the most common malignant tumors that lead to cancer-related death worldwide, and it has an increasing incidence rate. Approximately 20% to 30% of patients with CRC are found to have distant metastases at the time of diagnosis [1]. To date, with recent advances in systemic chemotherapy, nonoperative treatment has become the mainstay of treatment in patients with incurable metastatic CRC [2, 3]. Given the progress in chemotherapy regimens and palliative techniques such as endoluminal stenting and given the high mortality of cancer-directed surgery, the prognostic impact of a primary tumor resection in patients with stage IV CRC has been under debate [4, 5, 6]. A previous analysis of Surveillance Epidemiology and End Results (SEER)-Medicare-linked data between 1991 and 1999 reported a 72% cancer-directed surgery rate in elderly patients (age ≥ 65) with stage IV CRC [6]. However, more recent SEER-Medicare data from 2001 to 2007 demonstrated a statistically significant decrease in the rate of surgical resections of primary tumors from 64.6% in 2001 to 57.1% in 2007 [7]. Similarly, The Netherlands' Cancer Registry also found a significant decrease in primary tumor resection rates from 66% to 56% and an increase in systemic chemotherapy from 2.0% in 1989-1993 to 40% in 2004-2006 in elderly patients with stage IV CRC disease [8]. These treatment trends may indicate that practitioners are rapidly adopting the use of modern combination chemotherapy and that a paradigm shift in the treatment of stage IV CRC is beginning. Current practice guidelines from the National Comprehensive Cancer Network (NCCN) recommend a resection of the primary tumor only if patients are symptomatic or have metastatic sites amenable to a potentially-curative resection. Although the rationale for an up-front primary tumor resection is based on an attempt to resolve potential complications from the primary tumor, such as bowel obstruction, uncontrollable bleeding, or tumor perforation [6, 9], the critical role of surgery for patients with incurable stage IV CRC is still inconclusive, especially for patients with stage IVB CRC. Furthermore, proper prognostic clinical parameters, such as age, performance status, pathological grading, or localization of the primary tumor, should be considered before undertaking surgery in elderly patients with stage IV CRC. Although very limited evidence is available with respect to the survival benefit of a primary tumor resection in patients with stage IV CRC, recent studies demonstrated a 31% reduction in mortality with surgical resection of the primary tumor and an increase in survival in elderly patients with stage IV CRC [10, 11]. Consistent with previous studies, our retrospective study showed that patients who underwent a primary tumor resection followed by chemotherapy had a significantly longer survival time than patients who received first-line chemotherapy (17.2 vs. 13.6 months, P = 0.002) [12]. On the basis of the current limited results, a primary tumor resection is potentially associated with survival benefits in elderly patients with stage IV CRC. However, primary-tumor-related complications are a major concern. The rates of complication in patients with an unresected primary tumor have been reported to range from 11.0% to 30% [2, 13, 14]. This study analyzed retrospectively the survival outcomes and the prognostic factors in elderly patients with stage IVB CRC. The current study showed that the patients in the resection group had significantly longer median survival times compared to the patients in the nonresection group (12.43 months vs. 3.58 months, P < 0.001). In addition, male gender, higher level of carcinoembryonic antigen, higher aspartate aminotransferase level, and nonresection of the primary tumor were independent poor prognostic factors on the multivariate analysis. However, the relatively short follow-up time and the small sample size are major drawbacks to interpreting the survival benefits and the prognostic factors clearly [15]. A large-scale, randomized study is needed to clearly establish the true benefits primary tumor resection for stage IVB CRC. In conclusion, the appropriate role of a surgical resection for treating stage IVB CRC, including its prognostic impact on tumor-related symptom control, its survival benefits and its impact on quality of life, remains to be fully evaluated.