Use of kidney failure risk equation as a tool to evaluate referrals from primary care to specialist nephrology care.

BACKGROUND: With rising costs and burden of chronic kidney disease (CKD), timely referral of patients to a kidney specialist is crucial. Currently, Kidney Health Australia (KHA) uses a 'heat map' based on severity and not future risk of kidney failure, whereas the kidney failure risk equation (KFRE) score predicts future risk of progression. AIMS: Evaluate whether a KFRE score assists with timing of CKD referrals. METHODS: Retrospective cohort of 2137 adult patients, referred to tertiary hospital outpatient nephrologist between 2012 and 2020, were analysed. Referrals were analysed for concordance with the KHA referral guidelines and, with the KFRE score, a recommended practice. RESULTS: Of 2137 patients, 626 (29%) did not have urine albumin-to-creatinine ratio (UACR) measurement at referral. For those who had a UACR, the number who met KFRE preferred referral criteria was 36% less than KHA criteria. If the recommended KFRE score was used, then fewer older patients (≥40 years) needed referral. Positively, many diabetes patients were referred, even if their risk of kidney failure was low, and 29% had a KFRE over 3%. For patients evaluated meeting KFRE criteria, a larger proportion (76%) remained in follow-up, with only 8% being discharged. CONCLUSIONS: KFRE could reduce referrals and be a useful tool to assist timely referrals. Using KFRE for triage may allow those patients with very low risk of future kidney failure not be referred, remaining longer in primary care, saving health resources and reducing patients' stress and wait times. Using KFRE encourages albuminuria measurement.

Maximising access to kidney transplantation: A single-centre audit of people receiving dialysis.

BACKGROUND: Despite transplantation being well documented as the renal replacement therapy option that gives the best morbidity and mortality outcomes, the best quality of life and the best value for healthcare dollar, not all patients are on a kidney transplant waiting list. OBJECTIVES: The aims of this study were (1) to explore possible reasons for a demonstrated a higher rate of people being listed as suitable for transplant in a non-transplanting unit and (2) to describe a formal process of review and referral as a method for maximising the number of people gaining access to the transplant waiting list. METHODS: We prospectively audited all patients who were undergoing dialysis in our metropolitan, non-transplanting renal unit annually over six years to determine whether not being on the transplant waiting list was in keeping with available eligibility guidelines of medical and behavioural criteria. RESULTS: In every age group, the percentage of patients listed for transplant was higher than that seen in national data. The most common reasons for people not to be listed were malignancy, obesity and cardiovascular disease. This unit's patients had fewer smokers, less females and less Aboriginal and Torres Strait Islanders which may have contributed towards a higher rate of activation on the list. CONCLUSION: In this dialysis patient population having a formal process of review for suitability and referral, as well as a specialist renal transplant coordinator nurse positively affected the number of patients being activated on the transplant waiting list.

The focal adhesion targeting domain of p130Cas confers a mechanosensing function.

Members of the Cas family of focal adhesion proteins contain a highly conserved C-terminal focal adhesion targeting (FAT) domain. To determine the role of the FAT domain in these proteins, we compared wild-type exogenous NEDD9 with a hybrid construct in which the NEDD9 FAT domain had been exchanged for the p130Cas (also known as BCAR1) FAT domain. Fluorescence recovery after photobleaching (FRAP) revealed significantly slowed exchange of the fusion protein at focal adhesions and significantly slower two-dimensional migration. No differences were detected in cell stiffness as measured using atomic force microscopy (AFM) and in cell adhesion forces measured with a magnetic tweezer device. Thus, the slowed migration was not due to changes in cell stiffness or adhesion strength. Analysis of cell migration on surfaces of increasing rigidity revealed a striking reduction of cell motility in cells expressing the p130Cas FAT domain. The p130Cas FAT domain induced rigidity-dependent phosphorylation of tyrosine residues within NEDD9. This in turn reduced post-translational cleavage of NEDD9, which we show inhibits NEDD9-induced migration. Collectively, our data therefore suggest that the p130Cas FAT domain uniquely confers a mechanosensing function.

NURSES' BEREAVEMENT NEEDS AND ATTITUDES TOWARDS PATIENT DEATH: A QUALITATIVE DESCRIPTIVE STUDY OF NURSES IN A DIALYSIS UNIT.

BACKGROUND: Dialysis nurses have a unique relationship with their patients and often require bereavement support should a patient death occur. This study was conducted in 2014 and aimed to explore the attitudes of dialysis nurses to death and dying and to identify suitable bereavement strategies following a death of a patient. METHODS: A purposeful, convenience sample of all nurses employed in the dialysis service completed a demographic profile and The Death Attitudes Profile Revisited (DAP_R) survey. RESULTS: There were 52 responses to the survey (98% response rate). The mean age of the participants was 45 years ± 8.0 years; 87% had >10 years nursing experience. Nurses suggest that debriefing and the use of a counsellor would support them in their grieving process while new graduate nurses appear to require extra support following a patient death. Analysis of the death attitude profile-revised (DAP-R) showed significant relationships between fear of death/death avoidance as well as fear of death/neutral acceptance. Spirituality and religion correlate strongly with 'Approach Acceptance' in this study group. Forty-four percent people who 'approach acceptance' of death can be explained by the strength of religious beliefs. CONCLUSIONS: Many dialysis nurses appear to have strong religious or spiritual belief systems and this contributes to their acceptance of death, although there also appears to be a degree of death avoidance. The study has highlighted the need to provide adequate bereavement support for dialysis nurses.

PP2A phosphatase suppresses function of the mesenchymal invasion regulator NEDD9.

The mesenchymal mode of cancer cell invasion characterized by active adhesion turnover and a polarized actin cytoskeleton, is critically regulated by the adaptor protein NEDD9/HEF1/Cas-L. While it is known that NEDD9 is subject to extensive phosphorylation modification, the molecules that determine NEDD9 phosphorylation to stimulate adhesion turnover and mesenchymal cell morphologies are currently unknown. Earlier studies have suggested that the serine/threonine phosphatase PP2A regulates interconversion between a low molecular mass NEDD9 phosphoform and higher molecular mass phosphoforms. However, previous studies have used chemical inhibitors to block PP2A activity. In the present study we therefore aimed to specifically inhibit PP2A activity via siRNA and dominant negative approaches to investigate the effect of PP2A on interconversion between 115 kDa and 105 kDa NEDD9 and determine the functional consequence of PP2A activity for NEDD9 function. Strikingly, we find that while the phosphatase inhibitor Calyculin A indeed abrogates detachment-induced dephosphorylation of the 115 kDa NEDD9 phosphoform, PP2A depletion does not inhibit 115 kDa to 105 kDa interconversion. Our data suggest instead that PP2A targets discrete NEDD9 phosphorylation modifications separate to the events that mediate interconversion between the two forms. Functionally, PP2A depletion increases NEDD9 mediated cell spreading and mutation of S369 in the serine-rich region of NEDD9 to aspartate mimics this effect. Importantly, mutation of S369 to alanine abrogates the ability of dominant negative PP2A to increase NEDD9-mediated cell spreading. Collectively, our data reveal that the tumour suppressor PP2A may act via S369 to regulated NEDD9-mediated cell spreading.

Essential biological processes of an emerging pathogen: DNA replication, transcription, and cell division in Acinetobacter spp.

Within the last 15 years, members of the bacterial genus Acinetobacter have risen from relative obscurity to be among the most important sources of hospital-acquired infections. The driving force for this has been the remarkable ability of these organisms to acquire antibiotic resistance determinants, with some strains now showing resistance to every antibiotic in clinical use. There is an urgent need for new antibacterial compounds to combat the threat imposed by Acinetobacter spp. and other intractable bacterial pathogens. The essential processes of chromosomal DNA replication, transcription, and cell division are attractive targets for the rational design of antimicrobial drugs. The goal of this review is to examine the wealth of genome sequence and gene knockout data now available for Acinetobacter spp., highlighting those aspects of essential systems that are most suitable as drug targets. Acinetobacter spp. show several key differences from other pathogenic gammaproteobacteria, particularly in global stress response pathways. The involvement of these pathways in short- and long-term antibiotic survival suggests that Acinetobacter spp. cope with antibiotic-induced stress differently from other microorganisms.

Role of conserved active site residues in catalysis by phospholipase B1 from Cryptococcus neoformans.

Phospholipase B1 (PLB1), secreted by the pathogenic yeast Cryptococcus neoformans, has an established role in virulence. Although the mechanism of its phospholipase B, lysophospholipase, and lysophospholipase transacylase activities is unknown, it possesses lipase, subtilisin protease aspartate, and phospholipase motifs containing putative catalytic residues S146, D392, and R108, respectively, conserved in fungal PLBs and essential for human cytosolic phospholipase A2 (cPLA2) catalysis. To determine the role of these residues in PLB1 catalysis, each was substituted with alanine, and the mutant cDNAs were expressed in Saccharomyces cerevisiae. The mutant PLB1s were deficient in all three enzymatic activities. As the active site structure of PLB1 is unknown, a homology model was developed, based on the X-ray structure of the cPLA2 catalytic domain. This shows that the two proteins share a closely related fold, with the three catalytic residues located in identical positions as part of a single active site, with S146 and D392 forming a catalytic dyad. The model suggests that PLB1 lacks the "lid" region which occludes the cPLA2 active site and provides a mechanism of interfacial activation. In silico substrate docking studies with cPLA2 reveal the binding mode of the lipid headgroup, confirming the catalytic dyad mechanism for the cleavage of the sn-2 ester bond within one of two separate binding tracts for the lipid acyl chains. Residues specific for binding arachidonic and palmitic acids, preferred substrates for cPLA2 and PLB1, respectively, are identified. These results provide an explanation for differences in substrate specificity between lipases sharing the cPLA2 catalytic domain fold and for the differential effect of inhibitors on PLB1 enzymatic activities.

N-linked glycosylation sites affect secretion of cryptococcal phospholipase B1, irrespective of glycosylphosphatidylinositol anchoring.

Secreted phospholipase B enzymes (PLB1) with high levels of N-linked glycosylation are proven fungal virulence determinants. We demonstrated that removal of N-linked glycans from secreted cryptococcal PLB1 leads to loss of enzyme activity. To determine if individual N-glycan attachment sites affect secretion of active enzyme, we altered three along the entire length of the protein, by site-directed mutagenesis, namely Asn56, Asn430 and Asn550 to Ala, in wild-type PLB1 (full length) and a glycosylphosphatidylinositol (GPI) anchorless version (PLB1(GPI-)) that is hypersecreted due to lack of membrane association. Alteration of Asn56 and Asn550 in both PLB1 and PLB1(GPI-) abolished enzyme secretion while alteration of Asn430 reduced secretion by 60%, following expression in Saccharomyces cerevisiae. Reduced secretion coincided with reduced enzyme in membranes and cell walls confirming a reduction in the rate of PLB1 transport to the cell surface. Deglycosylation of cryptococcal PLB1 increased its susceptibility to proteolysis suggesting that the absence of full glycosylation status leads to degradation of unstable PLB1, resulting in reduced traffic through the secretory pathway. We conclude that individual N-linked glycans are required for optimal transport of PLB1 to the cell surface and optimal secretion of both PLB1 and PLB1(GPI-).

Secretion of cryptococcal phospholipase B1 (PLB1) is regulated by a glycosylphosphatidylinositol (GPI) anchor.

The secreted, multifunctional enzyme PLB1 (phospholipase B1 protein encoded by the PLB1 gene) is a virulence determinant of the pathogenic fungus Cryptococcus neoformans, but the mechanism of its secretion is unknown. The cryptococcal PLB1 gene encodes putative, N-terminal LP (leader peptide) and C-terminal GPI (glycosylphosphatidylinositol) anchor attachment motifs, suggesting that PLB1 is GPI-anchored before secretion. To investigate the role of these motifs in PLB1 secretion, four cDNA constructs were created encoding the full-length construct (PLB1) and three truncated versions without the LP and/or the GPI anchor attachment motifs [(LP-)PLB1 (PLB1 expressed without the LP consensus motif), (LP-)PLB1(GPI-) (PLB1 expressed without the LP and GPI consensus motifs) and PLB1(GPI-) (PLB1 expressed without the GPI anchor attachment motif) respectively]. The constructs were ligated into pYES2, and galactose-induced expression was achieved in Saccharomyces cerevisiae. The LP was essential for secretion of the PLB1 protein and its three activities (PLB, lysophospholipase and lysophospholipase transacylase). Deletion of the GPI motif to create PLB1(GPI-) resulted in a redistribution of activity from the cell wall and membranes to the secreted and cytosolic fractions, with 36-54% of the total activity being secreted as compared with <5% for PLB1. PLB1 produced the maximum cell-associated activity (>2-fold more than that for PLB1(GPI-)), with 75-86% of this in the cell-wall fraction, 6-19% in the membrane fraction and 3-7% in the cytosolic fraction. Cell-wall localization was confirmed by release of activity with beta-glucanase in both S. cerevisiae recombinants and wild-type C. neoformans. The dominant location of PLB1 in the cell wall via GPI anchoring may permit immediate release of the enzyme in response to changing environmental conditions and may represent part of a novel mechanism for regulating the secretion of a fungal virulence determinant.