Natural History of Common Autologous Arteriovenous Fistulae: Consequences for Planning of Dialysis.

OBJECTIVES: The aim was to study primary failure, maturation times, and survival of common arteriovenous fistulae (AVF) to aid planning for vascular access, and to assess which strategy results in most dialysis days. METHODS: This was a longitudinal cohort study. Two databases of access operations and dialysis sessions over 9 years with 12-year follow-up were reviewed. Functional dialysis use is defined as achieving six consecutive dialysis sessions with two needles on AVF. Primary failure (PF) is failure to achieve functional dialysis use. Maturation time, calculated only for patients on dialysis with a central line at AVF operation, is defined from the operation date to the functional dialysis date. Cumulative patency, including PF, is calculated from the operation to date of AVF abandonment and is compared using Kaplan­Meier curves and adjusted hazard ratios (HRs). RESULTS: A total of 1206 AVF, 689 (57%) radiocephalic AVF (RCAVF), 383 (32%) brachiocephalic AVF (BCAVF), and 134 (11%) brachiobasilic AVF (BBAVF), were analysed. PF was 23%. PF was lower for BCAVF (17%) than RCAVF (26%) and BBAVF (26%) (p = .006). PF was higher for women (OR 1.59, 95% CI: 1.21­2.09) and patients with vascular kidney disease (OR 1.69, 95% CI: 1.19­2.59). Median maturation time was 10.3 weeks. Cumulative patency was worse for BCAVF (HR 1.36, 95% CI: 1.03­1.81) and BBAVF (HR 1.63 95% CI: 1.12­2.38), for patients on dialysis at AVF creation (HR 1.55, 95% CI: 1.13­2.12), and diabetics (HR 1.55, 95% CI: 1.12­1.85). RCAVFs resulted in 3% more dialysis-person-years (py) per 100 operations for all patients and in 15% more dialysis-py in the over 80s. CONCLUSION: RCAVFs have higher PF, but better survival than other AVF, and result in more dialysis time. AVF created pre-dialysis have better survival. An average maturation time of 10 weeks should be considered if planning to start dialysis on an AVF.

An analysis of Pseudomonas genomic diversity in take-all infected wheat fields reveals the lasting impact of wheat cultivars on the soil microbiota.

Manipulation of the soil microbiota associated with crop plants has huge promise for the control of crop pathogens. However, to fully realize this potential we need a better understanding of the relationship between the soil environment and the genes and phenotypes that enable microbes to colonize plants and contribute to biocontrol. A recent 2 years of investigation into the effect of wheat variety on second year crop yield in the context of take-all fungal infection presented the opportunity to examine soil microbiomes under closely defined field conditions. Amplicon sequencing of second year soil samples showed that Pseudomonas spp. were particularly affected by the wheat cultivar grown in year one. Consequently, 318 rhizosphere-associated Pseudomonas fluorescens strains were isolated and characterized across a variety of genetic and phenotypic traits. Again, the wheat variety grown in the first year of the study was shown to exert considerable selective pressure on both the extent and nature of Pseudomonas genomic diversity. Furthermore, multiple significant correlations were identified within the phenotypic/genetic structure of the Pseudomonas population, and between individual genotypes and the external wheat field environment. The approach outlined here has considerable future potential for our understanding of plant-microbe interactions, and for the broader analysis of complex microbial communities.

Assessment of core and accessory genetic variation in Rhizobium leguminosarum symbiovar trifolii strains from diverse locations and host plants using PCR-based methods.

UNLABELLED: The nitrogen-fixing symbiosis between Rhizobium leguminosarum and host legumes is recognized as a key part of sustainable agriculture. A culture collection containing rhizobia isolated from legumes of economic importance in the UK and worldwide, maintained at Rothamsted Research for many years, provided material for this study. We aimed to develop and validate efficient molecular diagnostics to investigate whether the host plant or geographical location had a greater influence on the genetic diversity of rhizobial isolates, and the extent to which the core bacterial genome and the accessory symbiosis genes located on plasmids were affected. To achieve this, core housekeeping genes and those involved in symbiosis interactions were sequenced and compared with genome-sequenced strains in the public domain. Results showed that some Rh. leguminosarum symbiovar trifolii strains nodulating clovers and Rh. leguminosarum sv. viciae strains nodulating peas and vicias shared identical housekeeping genes, clover nodule isolates from the same location could have divergent symbiosis genes, and others isolated on different continents could be very similar. This illustrates the likely co-migration of rhizobia and their legume hosts when crops are planted in new areas and indicates that selective pressure may arise from both local conditions and crop host genotypes. SIGNIFICANCE AND IMPACT OF THE STUDY: The nitrogen-fixing symbiosis between Rhizobium leguminosarum and host legumes has been recognized as a key part of sustainable agriculture for many years; this study provides new tools to study rhizobial biogeography which will be invaluable for extending the cultivation of legumes and indicating whether or not inoculation is necessary.

Going Virtual: Transitioning an Older Adult Community Health Clinical Course to Online During COVID-19.

BACKGROUND: Nursing students in a community health course implemented a quality improvement project with active older adults (AOA). This article describes a process for transitioning an in-person community health quality improvement (QI) project to online. METHOD: To communicate with AOA, students created a blog, "Healthy Living From Home," that enabled communication among the AOA, partner organizations staff, and students. A quick response code was created that linked to the 6-week program. At the end of the 6 weeks, participants were asked to complete a survey. RESULTS: Data collected from the QI project website tracked more than 1,000 visits to the blog. Participants rated project enjoyment, helpfulness, and educational content as 4.5 on a 5-point Likert scale. CONCLUSION: Using a multifocal online format to engage with AOA was successful and can continue to be used in the future. [J Nurs Educ. 2023;62(X):XXX-XXX.].

Physical inactivity is a major contributor to ovariectomy-induced sarcopenia.

Since the mechanism(s) underlying menopause-related sarcopenia remain unknown we aimed to investigate the role of physical inactivity in its etiology. Ovariectomized and sham-operated rats were allocated into 2 experimental groups: (1) sedentary-standard housing; and (2) exercise-housed with running wheel. After a 9-month experimental period, soleus muscle structure and biochemical properties were analyzed. No differences existed in muscle fibre size or ultrastructure between sedentary sham and ovariectomized animals housed in standard conditions. In the exercise groups, average daily running distance was 10-fold less in ovariectomized compared to sham-animals. Further, in exercised animals, soleus fibre size was smaller in ovariectomized compared to sham-animals. Nonetheless, compared to both sedentary groups, muscle fibre size was larger in the exercised ovariectomized animals. Our results indicate that ovariectomy-induced sarcopenia is not due to the loss of ovarian hormones per se, but is largely due to physical inactivity.

The Dynamic Anaerobic Reactor & Integrated Energy System (DARIES) model: model development, validation, and sensitivity analysis.

The Dynamic Anaerobic Reactor & Integrated Energy System (DARIES) model has been developed as a biogas and electricity production model of a dairy farm anaerobic digester system. DARIES, which incorporates the Anaerobic Digester Model No. 1 (ADM1) and simulations of both combined heat and power (CHP) and digester heating systems, may be run in either completely mixed or plug flow reactor configurations. DARIES biogas predictions were shown to be statistically coincident with measured data from eighteen full-scale dairy operations in the northeastern United States. DARIES biogas predictions were more accurate than predictions made by the U.S. AgSTAR model FarmWare 3.4. DARIES electricity production predictions were verified against data collected by the NYSERDA DG/CHP Integrated Data System. Preliminary sensitivity analysis demonstrated that DARIES output was most sensitive to influent flow rate, chemical oxygen demand (COD), and biodegradability, and somewhat sensitive to hydraulic retention time and digester temperature.

Simulated Home Visit to Promote Chronic Disease Management Competencies in Prelicensure Nursing Students.

BACKGROUND: Conducting a best possible medication history (BPMH), while using effective patient communication skills, falls within the nursing scope of practice and is recommended at all care levels. Nursing students should be taught these skills before entering clinical practice, but evidence about effective teaching strategies is limited. APPROACH: A standardized patient-facilitated home visit simulation was utilized in a prelicensure nursing program to practice a BPMH while using effective patient communication skills. OUTCOMES: All students correctly identified medications listed on the patient history, and most identified omitted medications (90.1%), transposed medications (91.6%), and incorrect medication usage (91.6%). All students demonstrated effective patient communication skills-using open-ended questions and inquiring about medication usage. CONCLUSION: Incorporating a standardized patient-facilitated home visit BPMH simulation allows students the opportunity to practice and achieve BPMH competency essential for nurses.

Transitioning Community Health Clinical Experiences to an Online Format During COVID-19.

BACKGROUND: This article describes how nursing students in a community health course transitioned to an online clinical experience when coronavirus disease 2019 limited in-person gatherings. METHOD: A weekly video series was created to provide content to help educate 18 at-risk women using the Plan-Do-Study-Act cycle. RESULTS: Objectives for the nursing students were met. Successful implementation occurred, and objectives for the community health class were met; however, engagement was more difficult to achieve. CONCLUSION: Transitioning to online video conferencing allowed the nursing students to still engage with the study participants. Using the PDSA cycle allowed for structured changes to be made. [J Nurs Educ. 2022;61(3):159-161.].

Inactivation of plant infecting fungal and viral pathogens to achieve biological containment in drainage water using UV treatment.

AIM: To explore whether ultraviolet (UV) light treatment within a closed circulating and filtered water drainage system can kill plant pathogenic species. METHODS AND RESULTS: Ultraviolet experiments at 254 nm were conducted to determine the inactivation coefficients for seven plant pathogenic species. At 200 mJ cm(-2), the individual species log reductions obtained for six Ascomycete fungi and a cereal virus were as follows: Leptosphaeria maculans (9·9-log), Leptosphaeria biglobosa (7·1-log), Barley stripe mosaic virus (BSMV) (4·1-log), Mycosphaerella graminicola (2·9-log), Fusarium culmorum (1·2-log), Fusarium graminearum (0·6-log) and Magnaporthe oryzae (0·3-log). Dilution experiments showed that BSMV was rendered noninfectious when diluted to >1/512. Follow-up large-scale experiments using up to 400 l of microbiologically contaminated waste water revealed that the filtration of drainage water followed by UV treatment could successfully be used to inactivate several plant pathogens. CONCLUSIONS: By combining sedimentation, filtration and UV irradiation within a closed system, plant pathogens can be successfully removed from collected drainage water. SIGNIFICANCE AND IMPACT OF THE STUDY: Ultraviolet irradiation is a relatively low cost, energy efficient and labour nonintensive method to decontaminate water arising from a suite of higher biological containment level laboratories and plant growth rooms where genetically modified and/or quarantine fungal and viral plant pathogenic organisms are being used for research purposes.

p38 MAPK links oxidative stress to autophagy-related gene expression in cachectic muscle wasting.

Oxidative stress is a primary trigger of cachectic muscle wasting, but the signaling pathway(s) that links it to the muscle wasting processes remains to be defined. Here, we report that activation of p38 mitogen-activated protein kinase (MAPK) (phosphorylation) and increased oxidative stress (trans-4-hydroxy-2-nonenal protein modification) in skeletal muscle occur as early as 8 h after lipopolysaccharide (1 mg/kg) and 24 h after dexamethasone (25 mg/kg) injection (intraperitoneal) in mice, concurrent with upregulation of autophagy-related genes, Atg6, Atg7, and Atg12. Treating cultured C2C12 myotubes with oxidant hydrogen peroxide (4 h) resulted in increased p38 phosphorylation and reduced FoxO3 phosphorylation along with induced Atg7 mRNA expression without activation of NF-kappaB or FoxO3a transcriptional activities. Furthermore, inhibition of p38alpha/beta by SB202190 blocked hydrogen peroxide-induced atrophy with diminished upregulation of Atg7 and atrogenes [muscle atrophy F-box protein (MAFbx/Atrogin-1), muscle ring finger protein 1 (MuRF-1), and Nedd4]. These findings provide direct evidence for p38alpha/beta MAPK in mediating oxidative stress-induced autophagy-related genes, suggesting that p38alpha/beta MAPK regulates both the ubiquitin-proteasome and the autophagy-lysosome systems in muscle wasting.

Testosterone administration induces protection against global myocardial ischemia.

We tested the hypothesis that chronic testosterone treatment would promote a cardioprotective phenotype against ischemia/reperfusion (I/R) injury. For this study, 3-month-old F344 male rats underwent sham-surgery, orchiectomy (ORX), or ORX plus 21 days testosterone treatment (1.0 mg testosterone/day). At sacrifice, cardiac performance was assessed in a working heart model of I/R (25 min of global ischemia and 45 min of reperfusion). ORX reduced serum testosterone by approximately 98% and testosterone administration elevated serum testosterone to a concentration of 4.6-fold over that of Sham-operated controls (p<0.05). ORX did not significantly impair recovery of cardiac performance following I/R, but did increase cardiac release of lactate dehydrogenase (LDH) during pre- and post-ischemia (p<0.05). Testosterone administration prevented the ORX-induced increase in LDH during both pre- and post-ischemia and increased post-ischemic recovery of aortic flow, cardiac output, cardiac work, left ventricular developed pressure, and contractility (p<0.05) during reperfusion. Testosterone administration also increased left ventricular expression of catalase, but did not affect the expression of manganese superoxide dismutase, glutathione peroxidase, or sarcolemmal K (ATP) channel protein Kir6.2. Neither circulating nor cardiac concentrations of estradiol were altered by either treatment. We conclude that administration of high-dose testosterone confers cardioprotection through yet to be identified androgen-dependent mechanism(s).

Calpain-1 is required for hydrogen peroxide-induced myotube atrophy.

Recent reports suggest numerous roles for cysteine proteases in the progression of skeletal muscle atrophy due to disuse or disease. Nonetheless, a specific requirement for these proteases in the progression of skeletal muscle atrophy has not been demonstrated. Therefore, this investigation determined whether calpains or caspase-3 is required for oxidant-induced C2C12 myotube atrophy. We demonstrate that exposure to hydrogen peroxide (25 microM H2O2) induces myotube oxidative damage and atrophy, with no evidence of cell death. Twenty-four hours of exposure to H2O2 significantly reduced both myotube diameter and the abundance of numerous proteins, including myosin (-81%), alpha-actinin (-40%), desmin (-79%), talin (-37%), and troponin I (-80%). Myotube atrophy was also characterized by increased cleavage of the cysteine protease substrate alphaII-spectrin following 4 h and 24 h of H2O2 treatment. This degradation was blocked by administration of the protease inhibitor leupeptin (10 microM). Using small interfering RNA transfection of mature myotubes against the specific proteases calpain-1, calpain-2, and caspase-3, we demonstrated that calpain-1 is required for H2O2-induced myotube atrophy. Collectively, our data provide the first evidence for an absolute requirement for calpain-1 in the development of skeletal muscle myotube atrophy in response to oxidant-induced cellular stress.

Endosome pH measured in single cells by dual fluorescence flow cytometry: rapid acidification of insulin to pH 6.

The acidification of various ligands was measured on a cell by cell basis for cell suspensions by correlated dual fluorescence flow cytometry. Mouse 3T3 cells were incubated with a mixture of fluorescein- and rhodamine-conjugated ligands, and the ratio of fluorescein and rhodamine fluorescence was used as a measure of endosome pH. The calibration of this ratio by both fluorometry and flow cytometry is described. Dual parameter histograms of average endosome pH per cell versus amount of internalization were calculated from this data, for samples in the absence and presence of chloroquine added to neutralize acidic cellular vesicles. The kinetics of acidification of insulin were measured and compared with previous results obtained with the chloroquine ratio technique. Rapid acidification of internalized ligand was observed both for insulin, which was mostly internalized via nonspecific pathways, and for alpha 2-macroglobulin, which was mainly internalized by specific receptor-mediated endocytosis. The average pH observed for internalized insulin was less than pH 6 within 10 min after addition of insulin. At 30 min, the average pH began to decrease to approximately pH 5, presumably because of fusion of endosomes with lysosomes.

A mutation in the catalytic subunit of cAMP-dependent protein kinase that disrupts regulation.

A mutant catalytic subunit of adenosine 3',5'-monophosphate (cAMP)-dependent protein kinase has been isolated from Saccharomyces cerevisiae that is no longer subject to regulation yet retains its catalytic activity. Biochemical analysis of the mutant subunit indicates a 100-fold decreased affinity for the regulatory subunit. The mutant catalytic subunit exhibits approximately a threefold increase in Michaelis constant for adenosine triphosphate and peptide cosubstrates, and is essentially unchanged in its catalytic rate. The nucleotide sequence of the mutant gene contains a single nucleotide change resulting in a threonine-to-alanine substitution at amino acid 241. This residue is conserved in other serine-threonine protein kinases. These results identify this threonine as an important contact between catalytic and regulatory subunits but only a minor contact in substrate recognition.

Effects of gender and age on paediatric headache.

The aim of this study was to evaluate the impact of gender and age on headache characteristics and disability. Headache characteristics were assessed at an initial visit to a paediatric specialty care centre and five follow-up visits. A total number of 4121 patients were evaluated. Fifty-eight per cent of the sample was female. Boys were younger at their first headache and initial visit. They more frequently described headache pain as squeezing and location as top of the head. Girls reported more frequent and longer headaches. Girls more often described headache pain as sharp and location as back of the head. Age accounted for more variance than gender in headache severity, duration, frequency and disability. Gender differences exist in headache characteristics. Age is also an important factor in the variability in characteristics and disability. Longitudinal studies are needed to describe further the natural history of headaches in childhood and compare outcome between genders.

Friendships and social interactions of school-aged children with migraine.

We set out to evaluate the friendships and social behaviour of school-aged children with migraine. Concern exists regarding the impact of paediatric migraine on daily activities and quality of life. We hypothesized that children with migraine would have fewer friends and be identified as more socially sensitive and isolated than comparison peers. Sixty-nine children with migraine participated in a school-based study of social functioning. A comparison sample without migraine included classmates matched for gender, race and age. Children with migraine had fewer friends at school; however, this effect was limited to those in elementary school. Behavioural difficulties were not found. Middle-school students with migraine were identified by peers as displaying higher levels of leadership and popularity than comparison peers. Concern may be warranted about the social functioning of pre-adolescent children with migraine; however, older children with migraine may function as well as or better than their peers.

Novel tool for the study of cholecystokinin-stimulated pancreatic enzyme secretion.

The molecular events that mediate cholecystokinin (CCK)-stimulated pancreatic secretion are not well defined because of the complex receptor-binding and concentration-response characteristics of this hormone. Functional models of receptor occupancy initiating the cascade leading to secretion have been complicated by the inhibition of secretion effected by supramaximal concentrations of CCK. Recent report of a CCK analogue that does not exhibit supramaximal inhibition led us to synthesize a similar analogue that could also be radiolabeled for studies of receptor binding and affinity labeling, and for studies of second messenger activity. This probe, D-Tyr-Gly-[(Nle28,31)CCK-26-32]-phenethyl ester, was a fully efficacious secretagogue with no supramaximal inhibition, and, unlike native hormone, bound to a single class of sites present on both acini and membranes. Occupation of this site correlated well with stimulation of secretion. Evidence that this was indeed a CCK-binding site were the abilities of CCK and the antagonist L-364, 718 to inhibit binding of this analogue. Affinity labeling confirmed the identity of the site mediating secretory stimulation as a Mr = 85,000-95,000 protein. Whereas the nonhydrolyzable guanosine triphosphate analogue, 5'-guanylyl-imidodiphosphate, was a potent inhibitor of CCK binding, it had no effect on binding of this secretagogue, suggesting that a novel cascade not involving a guanine nucleotide-binding protein mediates CCK stimulation of pancreatic secretion.

Analysis of the reduced growth factor dependency of simian virus 40-transformed 3T3 cells.

We have measured in a defined serum-free medium the platelet-derived growth factor (PDGF) and insulin requirements of normal Swiss 3T3 cells, simian virus 40-transformed 3T3 cells, and partial revertants of simian virus 40-transformed 3T3 cells. Swiss 3T3 cells displayed strong requirements for both PDGF and insulin. Both of these requirements were significantly diminished in simian virus 40-transformed 3T3 cells. Analysis of the PDGF and insulin requirements of the revertants indicated that the loss of either of these two growth factor requirements was not necessarily linked to the other; rather, the growth factor requirements were specifically associated with other parameters of transformation. The reacquisition of a PDGF requirement cosegregated with reversion to density-dependent growth inhibition, whereas reacquisition of a normal insulin requirement cosegregated with reversion to a normal growth dependence on calf serum. Anchorage dependence was dissociable from both growth factor requirements. The relationship between the PDGF requirement and density-dependent growth inhibition was further analyzed in normal 3T3 cells by measuring the PDGF requirement at different cell densities. At high cell densities, the requirement for PDGF became significantly greater. We suggest that at least in part the ability of transformed cells to grow to high saturation densities results from their loss of a requirement for PDGF.

Overexpression of RPI1, a novel inhibitor of the yeast Ras-cyclic AMP pathway, down-regulates normal but not mutationally activated ras function.

A high-copy-number plasmid genomic library was screened for genes that when overexpressed down-regulate Ras protein activity in Saccharomyces cerevisiae. We report on the structure and characterization of one such gene, RPI1, which potentially encodes a novel 46-kDa negative regulator of the Ras-cyclic AMP pathway. Three lines of evidence suggest that the RPI1 gene product operates upstream to negatively regulate the activity of normal but not mutationally activated Ras proteins: (i) overexpressed RPI1 lowers cyclic AMP levels in wild-type yeast cells but not in yeast cells carrying the RAS2Val-19 mutation, (ii) overexpressed RPI1 suppresses the heat shock sensitivity phenotype induced by overexpression of normal RAS2 but does not suppress the same phenotype induced by RAS2Val-19, and (iii) disruption of RPI1 results in a heat shock sensitivity phenotype which can be suppressed by mutations that lower normal Ras activity. Thus, RPI1 appears to encode an inhibitor of Ras activity that shares a common feature with Ras GTPase-activating proteins in that it fails to down-regulate activated RAS2Val-19 function. We present evidence that the down-regulatory effect of RPI1 requires the presence of one of the two Ras GTPase activators, IRA1 and IRA2.

Dominant yeast and mammalian RAS mutants that interfere with the CDC25-dependent activation of wild-type RAS in Saccharomyces cerevisiae.

Two mutant alleles of RAS2 were discovered that dominantly interfere with wild-type RAS function in the yeast Saccharomyces cerevisiae. An amino acid substitution which caused the dominant interference was an alanine for glycine at position 22 or a proline for alanine at position 25. Analogous mutations in human H-ras also dominantly inhibited RAS function when expressed in yeast cells. The inhibitory effects of the mutant RAS2 or H-ras genes could be overcome by overexpression of CDC25, but only in the presence of wild-type RAS. These results suggest that these mutant RAS genes interfere with the normal interaction of RAS and CDC25 proteins and suggest that this interaction is direct and has evolutionarily conserved features.