[Time course of digital pressure during dialysis sessions in chronic hemodialysis patients. Prospective observational study of 49 patients]

OBJECTIVES

To describe and compare the evolution of digital pressure on both hands during a dialysis session in patients without digital ischemia, and to identify the parameters influencing the digital pressure.

MATERIALS

Patients with an upper limb vascular access were prospectively included. Digital systolic pressure on the third finger of both hands measured by photoplethysmography and brachial systolic pressure were recorded before dialysis (H0) and every hour (from H1 to H4).

RESULTS

Among 53 patients, 49 were included (exclusions: one surgery for ischemia, one hand tremor, two no consent). None of them had digital ischemia. Digital pressure homolateral to the vascular access was significantly lower compared with controlateral side before and during dialysis. Digital pressure significantly decreased on both sides during dialysis. Brachial pressure decreased significantly compared to H0. Only the brachial pressure decrease was correlated with the decrease of digital pressure. The digital pressure was less than 30 mmHg in six patients. No evidence of digital ischemia was reported after a 6-month follow-up.

CONCLUSION

To our knowledge, this is the first study showing a significant decrease of digital pressure in both hands during hemodialysis in patients without digital ischemia. Further studies are necessary to investigate which parameters can affect digital pressure and to look for clinical consequence of this measurement.

Integration of autophagy, proteasomal degradation, unfolded protein response and apoptosis

A single cell has the potential to kill an entire human being. Efforts to cure cancer are limited by survival of individual cancer cells despite immune surveillance and toxic therapies. Understanding the intricate network of pathways that maintain cellular homeostasis and mediate stress response or default into cell death is critical to the development of strategies to eradicate cancer. Autophagy, proteasomal degradation and the unfolded protein response (UPR) are cellular pathways that degrade and recycle excess or damaged proteins to maintain cellular homeostasis and survival. This review will discuss autophagy and how it is integrated with proteasomal degradation and UPR to govern cell fate through restoration of cellular homeostasis or default into the apoptotic cell death pathway. The first response of autophagy is macroautophagy, which sequesters cytoplasm including organelles inside double-membraned autophagosome vesicles that fuse with lysosomes to degrade and recycle the contents. Ubiquitination patterns on proteins targeted for degradation determine whether adapter proteins will bring them to developing autophagosomes or to proteasomes. Macroautophagy is followed by chaperone-mediated autophagy (CMA), in which Hsc70 (Heat shock cognate 70) selectively binds proteins with exposed KFERQ motifs and pushes them inside lysosomes through the LAMP-2A (Lysosome-associated membrane protein type 2A) receptor. These two processes and the lesser understood microautophagy, which involves direct engulfment of proteins into lysosomes, occur at basal and induced levels. Insufficient proteasome function or ER stress induction of UPR can induce autophagy, which can mitigate damage and stress. If this network is incapable of repairing the damage or overcoming continued stress, the default pathway of apoptosis is engaged to destroy the cell. Induction of macroautophagy by cancer therapeutics has led to clinical trials investigating combinations of HCQ (hydroxychloriquine) suppression of autophagy with apoptosis-inducing agents. Further study of the complex integration of autophagy, proteasomal degradation, UPR and apoptosis is likely to provide additional targets for our fight against cancer. This article is part of a Special Issue entitled "Apoptosis: Four Decades Later".

Advances in bile acid medicinal chemistry

Bile acids (BAs) are a family of steroidal molecules derived from cholesterol and biosynthesised in the pericentral hepatocytes of the liver. Structurally they may be regarded as consisting of two components, a rigid steroid nucleus and a short aliphatic side chain terminating in an alcohol or carboxyl group. Traditionally BAs are known for their ability to act as solubilising agents in the gut, aiding in the absorption of dietary lipids through the formation of mixed micelles. However the identification of BAs as ligands of the farnesoid X receptor (FXR) has lead to the realisation that these molecules have a wider range of biological effects. BAs regulate lipid and glucose homeostasis through activation of the FXR and the G-protein coupled receptor, TGR5. They can activate apoptotic, inflammatory and carcinogenic signalling pathways. BAs have also been shown to have anti-inflammatory effects. Interestingly, BAs are not restricted to the hepatic-intestinal system. Plasma BAs regulate BA synthesis and metabolism. BAs have recently been identified in cerebrospinal fluid. The BA, ursodeoxycholic acid has a potential role as a neuroprotectant in Huntington's disease and its taurine conjugate exhibits neuro-protective effects in vitro that may be relevant to Alzheimer's disease. This renaissance in BA biology has lead to the development of numerous medicinal chemistry programmes with different therapeutic targets, using BAs as lead structures. BA derivatives with increased efficacy and potency for FXR and TGR5 hold significant promise for the treatment of metabolic disorders. The peculiar effects of BAs on cell viability have been exploited for the design of selective cytocidal agents for treatment of various cancers. BA derivatives have also been screened with much success for anti-microbial and antifungal properties. Other targets include carbonic anhydrase for treatment of glaucoma and the glucocorticoid receptor for antiinflammatory effects. In this review interesting recent developments in the medicinal chemistry of these eclectic substances will be discussed.

Validation of diagnostic assays to screen broodstock for Flavobacterium psychrophilum infections

It is hypothesized that the frequency of bacterial coldwater disease outbreaks can be reduced through the detection of the aetiologic agent, Flavobacterium psychrophilum, in broodstock followed by culling of eggs from heavily infected broodstock. Before a culling programme can be instituted, however, it is necessary to determine the sensitivity and specificity of existing assays for the detection of F. psychrophilum. In this study, tissue and ovarian fluid samples were collected from 224 fish at five hatcheries and screened using an enzyme-linked immunosorbent assay (ELISA), a membrane-filtration fluorescent antibody test (MF-FAT), bacteriological culture and nested PCR. Latent class analysis was used to estimate sensitivity and specificity of kidney culture, kidney ELISA, nested PCR and MF-FAT. Analytical sensitivity of the ELISA varied but was greatest when bacteria were cultured under iron-limiting conditions. Diagnostic sensitivity estimates ranged from 0.02 (kidney culture) to 0.97 (kidney ELISA). Specificity estimates ranged from 0.02 (MF-FAT) to 0.98 (kidney ELISA). In a separate challenge experiment, the ELISA confirmed the presence of F. psychrophilum in sub-clinically infected fish. Results from this study demonstrate that the ELISA is an appropriate tool to screen broodstock and provides an indication of infection severity, which is crucial for implementation of a screening/culling programme.

Feedback on doctors' performance from parents and carers of children: a national pilot study

OBJECTIVES

To evaluate the reliability and validity of a children's carers' feedback tool, to explore the feasibility of delivering this nationally and to determine acceptability to doctors of this assessment.

PARTICIPANTS

122 UK paediatricians on the specialist register undertaking outpatient consultations.

DESIGN

Participants were each sent 50 forms for distribution to carers. Mean scores for each question, and for the overall pilot cohort were returned to participants with verbatim free text comments. Participating paediatricians' views were sought before and after receiving feedback.

RESULTS

122 doctors returned 4415 forms (mean 36 per doctor). All doctors scored highly with scores across all returned forms having a median of 4.58 (IQ range 0.17) where the maximum score was 5. Differences were observed between scores from female compared to male carers (p<0.05), from consultations rated by carer and child compared to carer alone (p<0.05) and from carers who had previously met the doctor compared to those in their first consultation (p<0.001). 'White' doctors received higher ratings than 'non-white' doctors (p<0.05) and white patients rated both white doctors and non-white doctors more highly than non-white patients (p<0.01). A minimum of 25 consultations rated by children's carers are needed for acceptable reliability. 93.9% of participants would be happy to be assessed in this way for the purposes of revalidation.

CONCLUSIONS

National delivery of a valid and reliable method of carer feedback is feasible. The scores received and acceptability in these self-selected doctors was high. Confounding variables may influence feedback, so guidance on interpretation may be needed.

Restenosis Is More Frequent After Carotid Stenting Than After Endarterectomy

Background and Purpose—

Carotid angioplasty and stenting (CAS) may be more often associated with residual or recurrent stenosis than carotid endarterectomy (CEA). We compared the rates of restenosis in patients treated with CAS or CEA in the EVA-3S trial.

Methods—

Five hundred seven patients (242 treated by CAS and 265 by CEA) had carotid ultrasound follow-up (mean carotid ultrasound follow-up, 2.1 years) according to a predefined protocol. Carotid restenosis of 50% to 69% was diagnosed on planimetry, whereas carotid restenosis of ≥70% or occlusion was diagnosed using either planimetry or velocity criteria.

Results—

The rate of carotid restenosis of ≥50% or occlusion was significantly higher after CAS (12.5%) than after CEA (5.0%; time ratio, 0.16; 95% CI, 0.03–0.76; P =0.02). The rates of severe restenosis of ≥70% or occlusion were low and did not differ significantly between the 2 groups (3-year rates are 3.3% in the CAS group and 2.8% in the CEA group). Age at baseline was the only vascular risk factor significantly associated with carotid restenosis. Our study could not detect any effect of carotid restenosis on ipsilateral stroke.

Conclusions—

The short-term rate of carotid restenosis of ≥50% or occlusion is ≈2.5-times more common after CAS than after CEA, a difference accounted for by an excess risk in moderate restenosis. More data with longer follow-up are needed to assess the rates of late severe restenosis and to determine the relation between restenosis and recurrent stroke over time.

Patient satisfaction with arthritis medication

Patient derived information to support the long term use of non-steroidal anti-inflammatory drugs (NSAIDs) is lacking. In contrast, data detailing the adverse effects of individual NSAIDs is accumulating. We determined the importance of NSAIDs as therapy to 153 patients with osteoarthritis (age range 36 to 92), comparing results in elderly and younger patients. Around half of the patients reported moderate relief of symptoms, with a further quarter reporting good, or even excellent, relief. One half of patients aged 75 years or less, but only one fifth of patients aged over 75 years, recalled having been informed of the adverse effects of NSAIDs. A total of 59 per cent of patients reported having used simple analgesics, such as paracetamol, as first line therapy. As some patients are helped by them, we suggest that efforts should be directed towards increasing the first line use of simple analgesics in patients with osteoarthritis and towards increasing patient awareness of potential NSAID-related adverse effects.

Distinguishing the cyanobacterial neurotoxin β-N-methylamino-L-alanine (BMAA) from other diamino acids

β-N-methylamino-L-alanine (BMAA) is produced by diverse taxa of cyanobacteria, and has been detected by many investigators who have searched for it in cyanobacterial blooms, cultures and collections. Although BMAA is distinguishable from proteinogenic amino acids and its isomer 2,4-DAB using standard chromatographic and mass spectroscopy techniques routinely used for the analysis of amino acids, we studied whether BMAA could be reliably distinguished from other diamino acids, particularly 2,6-diaminopimelic acid which has been isolated from the cell walls of many bacterial species. We used HPLC-FD, UHPLC-UV, UHPLC-MS, and triple quadrupole tandem mass spectrometry (UHPLC-MS/MS) to differentiate BMAA from the diamino acids 2,6-diaminopimelic acid, N-2(amino)ethylglycine, lysine, ornithine, 2,4-diaminosuccinic acid, homocystine, cystine, tryptophan, as well as other amino acids including asparagine, glutamine, and methionine methylsulfonium.