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Biomedical subjects

S Shaldon

Publications and source records attributed to S Shaldon.

174 records · Page 10Linked to original sources
PubMedDate not supplied

Detection of bacteria in dialysate and its antibody in long-term hemodialysis patients.

The relationship between endotoxin, which was detected in the dialysate, and incidence of its antibody formation in long-term hemodialysis patients was studied. Bacteria in the dialysate were first obtained, identified, and cultured, and then endotoxin was obtained from the bacteria by extraction with phenol. Using the endotoxin obtained and Escherichia coli J-5 as the antigen, the endotoxin antibody was measured in the serum of long-term hemodialysis patients by enzyme-linked immunosorbant assay (ELISA). It was found that the percentage of endotoxin antibody-positive patients was significantly higher in hemodialysis patients when compared with healthy controls. It was also significantly higher in hemodialysis patients using synthetic polymer membrane dialyzers compared with those using cuprophan membrane dialyzers. These results suggest that endotoxin antibody detected in hemodialysis patients was derived from the dialysate, and that the dialysate must be kept bacteria free, especially in patients using high-flux, highly permeable membrane dialyzers.

Amyloidosis↗
PubMedDate not supplied

The relationship between biocompatibility and interleukin-1.

Biocompatibility is redefined as the quality of being mutually tolerant with life. In so far as this represents a quality which is as likely to be achieved as is the alchemist's dream of turning lead into gold, a compromise approach is recommended. It is suggested that all extracorporeal or body invasive procedures stimulate the inflammatory defence mechanism of the body by stimulating the monocyte to produce a family of polypeptides currently known collectively as Interleukin-1 (IL-1). So far two dissimilar gene products have been cloned and there are probably more. The IL-1 group of polypeptides possess hormonal functions which orchestrate nearly every instrument of the body's defence system. Inducers of IL-1 are present in dialysate and induce bacterial pyrogen and acetate. In addition bacterial cell wall glycoprotein may be cleaved into muramyl peptides by the release of granulocyte lysozyme at the membrane interface. Muramyl dipeptides have been found in CAPD drain fluid and are more potent inducers of IL-1 than endotoxin. Membrane activation of the fifth component of the complement with the release of C5a will also induce monocytes to produce IL-1. The consequences of repeated stimulation of the acute phase response are undesirable and may include muscle wasting, osteopenia and bone cysts (Shrinking man syndrome), fibrosis of scapulo-humeral joints and the carpal-tunnel syndrome. These latter lesions are often associated with deposition of amyloid fibrils related to beta 2-microglobulin. Efforts to reduce these complications are urgently required.(ABSTRACT TRUNCATED AT 250 WORDS)

Biocompatible Materials↗
PubMedDate not supplied

Dialysis time: what you prescribe is what you get? (WYPIWYG).

The duration of a dialysis session is an essential parameter in determining dialysis efficiency and hence adequacy. The aim of this study was to measure the real dialysis time and to compare it to the prescribed time. For 12 months, 8412 dialysis treatments were allocated a number and a random sample of 100 was selected using a computer generated randomisation code. At the end of each dialysis, the time prescribed, the real time achieved, the blood volume exchanged, and any incidents occurring during the dialysis were noted. All the staff was aware of the study but nobody except the controller knew which dialysis was going to be controlled. The study population consisted of 48 patients, 25 males and 23 females. The mean duration of the prescribed dialysis time was 3.30 hours. Three patients used the same monitor per day. Results showed a loss of 10 minutes for 180 minutes dialysis prescription, 9.5 minutes for 210 minutes and 10.5 mintutes for 240-dialysis prescription. The dialyses with the greatest difference in time measured and prescribed occurred on the second (12 am to 3 am) shift (-6.23) which might be explained by the necessity for changing the bicarbonate cartridge during the shift. This loss of time represents a mean of 7 dialyses per year per patient. In conclusion, the prescribed time for a dialysis is very often not respected. A readjustment of the time during the treatment will be necessary to compensate for this loss of diffusion time and consequent efficiency.

Adult↗