Quotidian dialysis--update 2005

PURPOSE OF REVIEW: The interest in quotidian hemodialysis has increased further after the HEMO study reported that high-dose thrice-weekly hemodialysis failed to improve clinical outcomes. This, in combination with a significant volume of newly published data, made a review of the topic of quotidian hemodialysis timely. RECENT FINDINGS: The published research has revealed further evidence of cardiovascular and quality-of-life improvements as well as financial benefits with quotidian hemodialysis. Accrued worldwide experience has confirmed the previously published benefits of quotidian hemodialysis. There has been a significant effort by industry to produce patient-friendly machines for home hemodialysis. Reports on the use of daily hemodialysis and hemodiafiltration in children have appeared. An international registry of patients on quotidian hemodialysis has been created. The need for modification of the funding mechanisms and the lack of prospective randomized controlled studies on quotidian hemodialysis led to the funding of such studies by the National Institutes of Health in collaboration with Centers for Medicare and Medicaid services to be completed by 2008. The proper funding for daily home hemodialysis was secured in the province of British Columbia, Canada, and is under consideration elsewhere. SUMMARY: There is increasing evidence confirming that quotidian hemodialysis improves clinical outcomes in a cost-efficient manner. Provided that the reimbursement issues are resolved these modalities may be utilized extensively at home as well as in the in-center facilities. The revitalization of home hemodialysis will compensate for the decline in utilization of continuous ambulatory peritoneal dialysis and the nursing shortage encountered in most countries.     

Ground deposition impact of aerially applied fenthion on the fiddler crabs,Uca pugilator

Caged fiddler crabs, Uca pugilator, were exposed to field ULV applications to measure the impact of fenthion. Two nozzle systems, conventional flat-fan nozzles (Tee Jet 8002SS) and high-pressure hydraulic nozzles (1/8 MIS), were compared using single spray swaths. Fenthion residues were detected throughout the 4.83-km test zone for both systems. Heavy ground deposits (650-1,670 microg/m2) of fenthion were found within 1 km using the flat-fan nozzle systems, which resulted in 80% fiddler crab mortality. Less than 100 microg/m2 fenthion ground deposits were detected during the high-pressure nozzle trials. No fiddler crab mortality was observed within the first 1-km zone following 3 single swath applications repeated during 3 consecutive nights. We found also that when the fiddler crabs were exposed to 700-800 microg/m2 fenthion, mortality occurred. Significant crab mortality (>50%) was observed when residues exceeded 1,000 microg/m2.     

Body values: the case against compensating for transplant organs

Proposals to compensate families for transplantable organs are gathering momentum. The proposals assume that the body is dissociable from the self and can be treated like property. But such a view is out of step with the rest of the culture.     

Why do older people not get immunised against influenza? A community survey

Many older people who would benefit from influenza vaccine do not get immunised. We carried out a postal questionnaire survey of people aged 65 years and over living in the community to explore views about influenza vaccine and identify ways of improving uptake. Completed questionnaires were returned by 1468/2553 (57.5%). Vaccine coverage for 1998-1999 season was 50.5% (95% confidence interval (CI) 47.9-53.1%). Important predictor variables for non-uptake included absence of medical risk factors, perceived good health, lack of advice from a doctor or nurse, and negative views on vaccine efficacy and safety. Most people had to request vaccination, only one in five got a reminder from their general practitioner. There is scope for improving influenza vaccine coverage in older people by placing more emphasis in patient information materials on vaccine efficacy and safety and by greater use of reminders.     

Long-term food consumption and body weight changes in neotame safety studies are consistent with the allometric relationship observed for other sweeteners and during dietary restrictions

In long-term safety studies with neotame, a new high-intensity sweetener 7000-13,000 times sweeter than sucrose, the percent changes (%Delta) in body weight gain (BWG) in Sprague-Dawley rats were several-fold greater than the %Delta in overall food consumption (FC). This study investigates the question of whether the changes in BWG were adverse or secondary to small, long-term decrements in FC. The hypothesis tested in Sprague-Dawley rats was that the relationship between long-term %Delta in FC and %Delta in BWG is linear and in a ratio of 1:1. The %Delta in FC were compared to %Delta in BWG after 52 weeks on study in one saccharin (825 rats), two sucralose (480 rats), two neotame (630 rats), and five dietary restriction (>1000 rats) studies. Non-transformed plotting of data points demonstrated an absence of linearity between %Delta in FC and %Delta in BWG; however, log-log evaluation demonstrated a robust (R2=0.97) linear relationship between %Delta in FC and %Delta in BWG. This relationship followed the well-known allometric equation, y=bxa where x is %DeltaFC, y is %DeltaBWG, b is %DeltaBWG when DeltaFC=1, and a is the log-log slope. Thus, in Sprague-Dawley rats at week 52, the long-term relationship between %Delta in FC and %Delta in BWG was determined to be: %DeltaBWG=3.45(%DeltaFC0.74) for males and %DeltaBWG=5.28(%DeltaFC0.68) for females. Sexes were statistically different but study types, i.e., the high-intensity sweeteners saccharin and sucralose versus dietary restriction, were not. The %Delta in BWG are allometrically consistent with the observed %Delta in FC for these high-intensity sweeteners, including neotame. BW parameters are not appropriate endpoints for setting no-observed-effect levels (NOELs) when materials with intense taste are admixed into food. An approach using objective criteria is proposed to delineate BW changes due to toxicity from those secondary to reduced FC.     

A kinetic model for predicting the release rate of sparingly-water-soluble drugs from a hydrogel-coated polymeric matrix

Medical devices used for on-target drug delivery are often coated with a hydrogel coating for friction-reduction purpose. Thus, the delivery of a sparingly-water-soluble drug by such a device must diffuse through a nonerodable hydrogel layer. An empirical rate equation has been derived for such a kinetic model and predicts that the rate of drug release from such a device is directly proportional to the loading of the drug in the polymeric matrix. The validity of this kinetic model was examined by measuring the rate of release of 2,4,4'-trichloro-2'-hydroxydiphenyl ether from different hydrogel-coated (ethylene-vinyl acetate) copolymer stents containing a wide range of the drug. The experimentally determined release rates are in reasonably good agreement with those calculated from the empirical rate equation. Bioefficacy test results based on zone-of-inhibition test against Escherichia coli are also in good agreement with the release rate and drug-loading data predicted according to the empirical rate equation.