Running water: designing the dialysis clinic water room. Part 1.
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Hemodialysis Units, Hospital↗
Biomedical subjects
Robert Levin
Publications and source records attributed to Robert Levin.
Running water: measuring water quality in a dialysis facility. Part 2.
A summary of the primary points follows: The microbiological quality of the dialysis fluid represents an independent determinant of the nutritional status, in addition to known factors such as dose of dialysis and biocompatibility of the dialyzer membrane. Ultrapure dialysis fluid adds to the cost of the dialytic treatment, but improves the nutritional status in long-term hemodialysis patients. Water quality needs to be routinely monitored to ensure that the potential risk to patients from chemical and bacterial contaminants is minimized; this requires the implementation of a quality approach. The layout and design of the water room and water system are key to producing and maintaining high-quality dialysis fluid. Routine monitoring and preventive maintenance of the water system will ensure that high-quality dialysis fluid is delivered.
Equipment Design↗
Homeward Bound. Interview by Marla Fern Gold.
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California↗
Cyr61 and CTGF are molecular markers of bladder wall remodeling after outlet obstruction.
Cysteine-rich protein (Cyr61) and connective tissue growth factor (CTGF) are key immediate early growth factors with functions in cell proliferation, differentiation, and extracellular matrix synthesis. Studies were performed to assess the gene expression profile of Cyr61 and CTGF in rat urinary bladder during growth in response to partial outlet obstruction. The mRNA levels of Cyr61 as determined by ribonuclease protection assay increased sharply after 1 day and remained elevated throughout the time period of the obstruction. This correlates well with increased bladder weight. The CTGF mRNA levels seemed to peak within the second week of the urethral obstruction and correlate well with increased type I collagen mRNA. The expression pattern of either Cyr61 or CTGF proteins corroborated that of their respective mRNAs. Immunohistochemical analyses showed that immunoreactivity of Cyr61 was confined to detrusor smooth muscle and that of CTGF was detected within both detrusor muscle and lamina propria layers. These data strongly indicate the involvement of Cyr61 and CTGF in bladder wall remodeling as a result of the outlet obstruction.
Angiotensin II↗
Ocular input for human melatonin regulation: relevance to breast cancer.
The impact of breast cancer on women across the world has been extensive and severe. As prevalence of breast cancer is greatest in industrialized regions, exposure to light at night has been proposed as a potential risk factor. This theory is supported by the epidemiological observations of decreased breast cancer in blind women and increased breast cancer in women who do shift-work. In addition, human, animal and in vitro studies which have investigated the melatonin-cancer dynamic indicate an apparent relationship between light, melatonin and cancer, albeit complex. Recent developments in understanding melatonin regulation by light in humans are examined, with particular attention to factors that contribute to the sensitivity of the light-induced melatonin suppression response. Specifically, the role of spectral characteristics of light is addressed, and recent relevant action spectrum studies in humans and other mammalian species are discussed. Across five action spectra for circadian and other non-visual responses, a peak sensitivity between 446-484 nm was identified. Under highly controlled exposure circumstances, less than 1 lux of monochromatic light elicited a significant suppression of nocturnal melatonin. In view of the possible link between light exposure, melatonin suppression and cancer risk, it is important to continue to identify the basic related ocular physiology. Visual performance, rather than circadian function, has been the primary focus of architectural lighting systems. It is now necessary to reevaluate lighting strategies, with consideration of circadian influences, in an effort to maximize physiological homeostasis and health.
Breast Neoplasms↗
The implications of water quality in hemodialysis.
Water used in dialysis requires additional treatment to minimize patient exposure to potential contaminants that may be present in drinking water. Although standards for the chemical purity of water are in existence and have eliminated many of the problems seen in renal units in the 1970s, some problems remain, and the importance of newer contaminants arising from changes in water treatment at the municipal level are being recognized. Despite this, recent surveys have indicated considerable shortcomings in compliance with chemical standards. The water quality used in the preparation of dialysis fluid also requires minimal bacterial content. Staff working in renal units are frequently unaware of the level of microbiologic contamination in their dialysis fluid arising from the presence of biofilm in the dialysis machines and the water distribution network. Bacterial fragments generated by such biofilms are able to cross the dialysis membrane and stimulate an inflammatory response in the patient. Such inflammation has been implicated in the mortality and morbidity associated with dialysis. The desire to improve treatment outcomes has led to the application of more stringent standards for the microbiologic purity of dialysis fluid and to the introduction of ultraclean dialysis fluid into clinical practice.
Biofilms↗
On-line clearance: a useful tool for monitoring the effectiveness of the reuse procedure.
Reprocessing of a dialyzer for repeated use in the same patient is widely practiced. The dialyzer fiber bundle volume (FBV) is monitored as an indicator of the dialyzer's suitability for continued use, with standards for reprocessed dialyzers requiring a FBV of greater than 80% of a new dialyzer to be maintained. We have used on-line measurement of clearance of sodium (OLC module, Fresenius Medical Care, Walnut Creek, CA) to assess small molecule clearance changes during and between treatments for a group of 29 chronic hemodialysis patients who reused high flux polysulfone dialyzers (F80, Fresenius Medical Care, Lexington, MA) reprocessed using citric acid and heat (95 degrees C). Data pertaining to the initial, 5th, 10th, and 15th uses were analyzed and showed that, within a single dialysis session, there was a trend for the clearance to reduce throughout the treatment (p < 0.001). Overall, there was also a trend for clearances to decline with increasing number of reuses (p < 0.008). Changes in FBV occurred, but such changes remained within the guidelines suggested by standards. It is concluded that on-line clearance measurements provide a simple noninvasive method to monitor dialyzer performance over each use and between uses.
Aged↗