Dialyzer performance over prolonged reuse

Studies were performed in patients on maintenance hemodialysis to evaluate the role of prolonged dialyzer reuse in the management of end-stage renal disease. For this purpose the patients were dialyzed without interruption with the same hollow fiber dialyzers (GambroR 120M) reprocessed with the Lixivitron IIR equipment. The data obtained from in vivo clearances in sixteen patients demonstrate that membrane permeability to small solutes (urea, creatinine, phosphate) is maintained up to thirty dialyzer uses. In vitro studies confirmed this observation and established that clearances of larger solutes (vitamin B12) are also maintained over similar extensive dialyzer reuse. Hematological and blood gas studies were performed serially during dialysis in five additional patients. Although circulating leucocyte and neutrophil counts, hemoglobin concentration as well as arterial pH and partial pressures of oxygen and carbon dioxide changed appropriately during dialysis, there was no observable difference from the first to the twentieth use of the same dialyzer. Thus, these results clearly demonstrate that prolonged dialyzer reuse in end-stage renal disease patients constitutes a stable form of renal replacement therapy provided adequate dialyzer reprocessing is applied.

Osteoclast enlargement in endstage renal disease

In normal subjects and patients with endstage renal disease, osteoclast cell volumes were constructed using serial 2-micron thick plastic embedded sections from iliac crest bone biopsy specimens. Four cells randomly selected from each of the subjects were analyzed to give both the cell volume from the cumulative areas and thickness of each cell slice and also the cell axes taking the vector along the bone face as width or Y, thickness from the bone surface as breadth or X and vertical dimension length or Z. The mean cell volume was 6,230 microns3 in the control subjects and was significantly larger being 11,730 microns3 and 13,680 microns3 in the two patient groups. The cells showed polarity with the largest axes, Y and Z, being those in apposition to the bone surface. Howship's lacunae were enlarged in the patients and the cross-sectional area of an individual lacuna corresponded to the area of the contiguous osteoclast, r = 0.62, P less than 0.001. All patients had secondary hyperparathyroidism and osteoclast numbers were increased. There was no correlation between osteoclast size and duration of renal failure, previous vitamin D intake, or aluminum exposure. It is suggested that in ESRD, osteoclasts undergo both an increase in number and size and that these cells, being larger, remove more bone than the smaller cells in normal subjects.

Dialyser reuse: a study in applied medical ethics

A dialysis unit's introduction of automated recycling of dialysers is described. The responses of the staff and the patients are outlined, along with the pertinent ethical issues. Suggestions regarding the educational processes necessary with any innovation in long-term medical care are discussed.

Consent to dialyzer reuse: is it ethically necessary?

It is argued that consent by the patient to reuse dialyzers which have been mechanically cleansed is not required provided adequate standards of practice and safety are utilized. Based on medical benefits, administrative order and cost saving we propose that specific informed consent for such reuse should not be mandatory and that it could at times be unhelpful, both to care givers and recipients.

When is it an osteoclast?

Using acid phosphatase as a marker, osteoclasts were examined from single sections of undemineralised iliac crest biopsies from patients with renal failure and from normal controls. Eighty one per cent of the cells from controls and 56% of the cells from patients with renal failure appeared to be non-nucleated or mononucleated. Serial sections showed, however, that 73% of the control cells were actually multinucleated as were 91% of the patients' cells. Howship's lacunae were present in similar proportions in the controls whether the cells were multinucleated or not, suggesting that they should all be classed as osteoclasts. More multinucleated cells and lacunae were present in the patients with renal failure. It is concluded that all acid phosphatase cells adjacent to bone are osteoclasts and that the presence of more lacunae and multinucleated cells in renal failure is compatible with enhanced cellular resorption.

Reasons for drinking: motivational patterns and alcohol use among college students

A principal components factor analysis of survey data from 393 college student drinkers (178 males) extracted four dimensions from a set of 16 reasons for drinking: avoidance, social, sensation seeking, and enjoyment. Motivational patterns and the relationships with alcohol use were examined with a canonical correlation analysis. Three significant canonical variates were found. The first variate contained students with high scores on all motivational factors. They were heavy drinkers with many alcohol-related problems. The second variate indicated that drinkers who drank primarily for enjoyment tended to be women who drank moderately. Male beer drinkers with strong sensation seeking motivations formed the third variate.

Hemodialysis neutropenia and dialyzer reuse: role of the cleansing agent

As part of a study to evaluate the safety and efficacy of dialyzer reuse, a comparative study of two methods of dialyzer reprocessing, manual and automated, was conducted. Five stable end-stage renal disease patients on center hemodialysis were evaluated as to hematological and metabolic parameters throughout two series of three consecutive dialyses using first new and then reused dialyzers reprocessed according to each of the two methods. New dialyzers and reused dialyzers following automated reprocessing always induced a profound fall in circulating neutrophil counts shortly after the start of dialysis. Hemodialysis neutropenia was not observed, however, with reused dialyzers reprocessed manually unless the concentration of sodium hypochlorite (bleach) employed was made equal to that required in automated reprocessing by being raised from 1.0 to 4.3%. It would be reasonable to conclude from these results that among the various differences between the two dialyzer reprocessing methods, restoration of the original level of biocompatibility of the reused dialyzer's membrane is related to the concentration of the cleansing agent.

Bone marrow aluminium storage in renal failure

Using the staining method for aluminium with the ammonium salt of aurine tricarboxylic acid, aluminon, 18 patients with end stage renal disease gave positive reactions in iliac crest bone biopsies and 11 of these had positive staining in the bone marrow. In one the marrow was positive and the bone negative. The marrow reaction is putatively regarded as caused by aluminium storage in unidentified cells, possibly of the macrophage system which are strongly fluorescent when examined after prior tetracycline labelling. Marrow storage should be considered when assessing the bone aluminium burden.

Oral aluminum toxicity in a non-dialyzed patient with renal failure

A patient is described with chronic renal failure who developed toxic levels of aluminum in bone after one year of oral aluminum hydroxide ingestion with a total dose of 711 grams. Caution in the use of oral aluminum compounds is recommended in patients with renal failure.

Auto-immunity in patients with end-stage renal disease maintained on hemodialysis and continuous ambulatory peritoneal dialysis

Auto-immunity as assessed by rheumatoid factor, anti-DNA, antinuclear, smooth muscle and mitochondrial circulating antibodies was evaluated in 2 groups of 25 patients with end-stage renal disease (ESRD) being maintained either on hemodialysis or on continuous ambulatory peritoneal dialysis (CAPD). In the group of hemodialysis patients, 56% showed at least one serological abnormality on pre-dialysis samples: anti-DNA (8%), antinuclear (8%), smooth muscle (40%) and mitochondrial (4%) antibodies; on post-dialysis samples, 64% of the patients demonstrated abnormalities due to a rise in the incidence of anti-DNA antibodies from 8-24%. In the group of CAPD patients, 44% showed at least one serological abnormality: rheumatoid factor (4%), anti-DNA (16%), antinuclear (24%) and smooth muscle (4%) antibodies. These serological changes were generally scattered randomly within both groups. In the hemodialysis group, 2 abnormalities were present in 1 patient pre-dialysis and in 3 post-dialysis. One CAPD patient had 2 abnormalities. No correlation of these findings with age, sex, duration of dialysis and nature of renal disease could be found. The results are discussed in the context of possible abnormal antigenic stimulation in ESRD patients maintained on either form of dialysis.

Hypophosphatemia-induced hypercalcemia during acute renal failure

A case of hypophosphatemia-induced hypercalcemia during post-traumatic acute renal failure is described. Proposed causes for the hypophosphatemia include changes in tissue distribution of phosphate associated with hyperalimentation and phosphate losses during hemodialysis. In the absence of hyperparathyroidism the hypercalcemia as well as changes in osteoclast morphology found on bone biopsy are ascribed to a direct effect of hypophosphatemia on bone.

Alcohol, sexual arousal, and the transfer of excitation

Investigations of the alcohol-related disinhibition of responses to deviant sexual stimuli suggest that the pharmacological actions of ethanol have little influence on the disinhibition process. The mere belief that alcohol is consumed is sufficient to induce increased sexual arousal. Studies with conventional stimuli, however, suggest that interactions occur between the pharmacological presence of ethanol and the psychological expectations of its presence. Thus, this article examines the contribution of pharmacological, cognitive, and environmental variables to perceived sexual arousal. A balanced-placebo design varied drink instruction and drink content independently. Pictures that elicited either a low or moderate level of self-reported sexual arousal were viewed and evaluated by men (n = 64) and women (n = 64) after completing their drinks. The evaluations and arousal measures suggested significant Instruction X Content X Arousal interactions. The strongest perceptions of arousal occurred among individuals who did not know they were drinking alcohol (i.e., subjects who were told that their alcoholic drinks did not contain alcohol). Apparently, when drinkers were unaware of the alcohol intoxication, the pharmacological excitation induced by alcohol transferred to the perception and evaluation of the slides.

Action of phosphorus on calcium release in isolated perfused rat tails

A bone perfusion system using isolated rat tails was developed to study the action of inorganic phosphorus (Pi) on calcium (Ca) release in bone. Rats were either pre-labelled with 45Ca to study calcium removal from bone or 45Ca was added to the perfusate to study Ca deposition into bone. When perfusate Pi was increased from 3.5 to 5.25 mg/dl, a marked inhibition of 45Ca release was demonstrated. 85Sr microspheres, used to demonstrate differences in the flow of perfusate between bone and soft tissue, showed that the Pi effect was not due to alterations in perfusate flow to bone. Increasing the perfusate Pi concentration from 3.5 to 7 mg/dl did not increase 45Ca deposition into bone, nor did it affect baseline or PTH-stimulated cyclic AMP production. The Pi effect was inhibited by reducing the perfusate temperature to 4 degrees C, by using an anerobic perfusate, adding iodoacetate to the perfusate, and finally, by pre-treating the rats with actinomycin D prior to the experiment. Thus, in this model an increase in the Pi concentration of the perfusate inhibits Ca release from bone but does not increase Ca uptake by bone. The inhibitory effect appears to be dependent on normal cell metabolism.

Alcohol, sexual arousal, and the transfer of excitation

Investigations of the alcohol-related disinhibition of responses to deviant sexual stimuli suggest that the pharmacological actions of ethanol have little influence on the disinhibition process. The mere belief that alcohol is consumed is sufficient to induce increased sexual arousal. Studies with conventional stimuli, however, suggest that interactions occur between the pharmacological presence of ethanol and the psychological expectations of its presence. Thus, this article examines the contribution of pharmacological, cognitive, and environmental variables to perceived sexual arousal. A balanced-placebo design varied drink instruction and drink content independently. Pictures that elicited either a low or moderate level of self-reported sexual arousal were viewed and evaluated by men (n = 64) and women (n = 64) after completing their drinks. The evaluations and arousal measures suggested significant Instruction X Content X Arousal interactions. The strongest perceptions of arousal occurred among individuals who did not know they were drinking alcohol (i.e., subjects who were told that their alcoholic drinks did not contain alcohol). Apparently, when drinkers were unaware of the alcohol intoxication, the pharmacological excitation induced by alcohol transferred to the perception and evaluation of the slides.

Transcatheter embolization in the management of intractable uremic epistaxis

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Resolution of massive renal artery thromboembolism with conservative therapy

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Depth perception, eye alignment and cortical ocular dominance of dark-related cats

On first exposure to light, animals that have been reared from birth until about 4 months of age in total darkness exhibit substantial visual and visuomotor deficits, which decline in severity during the first few months following exposure to light. In order to determine whether dark-reared animals eventually acquire stereoscopic vision following exposure to light we examined the binocular status of 5 dark-reared animals two of which developed convergent eye alignment. The binocular status was assessed behaviorally by measurements of the ability of each animal to perceive depth using either one or both eyes, and physiologically by documentation of the distribution of cortical ocular dominance of a sample of visual acuity, their binocular depth perception remained very poor, comparable to the monocular performance of normal cats. In marked contrast to normal animals none of the dark-reared animals, even those with normal eye alignment, performed substantially better binocularly than monocularly, a result indicating the absence of a uniquely binocular mechanism for depth perception in these animals. Although the dark-reared animals were found to retain a substantial (but reduced) complement of binocularly influenced cortical neurons, the tuning of these cells for retinal disparity must be insufficiently precise to mediate depth perception under binocular viewing conditions that is superior to that which can be achieved monocularly.