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Biomedical subjects

F K Port

Publications and source records attributed to F K Port.

At least 163 records · Page 9Linked to original sources
PubMed1984

Complement activation and hypersensitivity reactions to dialysis membranes.

Certain patients receiving hemodialysis experience recurrent chest pain, dyspnea, and hypotension during exposure to new cuprophane-membrane dialyzers (the "first-use syndrome"). Because activation of complement may be involved in these events, we examined in vivo complement activation with new cuprophane membranes and in vitro activation by zymosan in 6 such patients, and compared them with 10 patients who did not have symptoms during dialysis. All patients with the first-use syndrome had maximal complement activation 10 minutes after initiation of dialysis, with C3a des-arginine (desArg), the stable metabolite of C3 activation, equal to 8533 +/- 157 ng per milliliter (mean +/- S.E.M.). In asymptomatic patients the maximal C3a desArg value occurred at 15 minutes and was only 2907 +/- 372 ng per milliliter (P less than or equal to 0.0001). At a concentration of 3.8 x 10(-5) g of zymosan per milliliter, patients with the first-use syndrome had a C3a desArg level of 29.6 +/- 1.4 micrograms per milliliter, whereas it was only 16.6 +/- 2.3 micrograms per milliliter in asymptomatic patients (P less than or equal to 0.0001). Two other patients, who experienced cardiopulmonary collapse during the first two minutes of dialysis, had a C3a desArg level of 18,900 and 7800 ng per milliliter, respectively. We conclude that the occurrence of adverse symptoms associated with new cuprophane-membrane dialyzers correlates with complement activation.

Adult↗
PubMed1982

A controlled study of supplementation with essential amino acids and alpha-keto acids in the conservative management of patients with chronic renal failure.

Oral therapy with essential amino acids (EAA) or alpha-keto acids (alpha-KA) has been recommended in patients with renal failure, but quality and quantity of optimal protein intake are still controversial. This study compares sequentially the effect of supplementation with EAA, and with alpha-KA versus placebo in 15 ambulatory patients with chronic renal failure (average creatinine clearance 10.8 ml/min), maintained on a protein diet of 0.57 g/kg body weight (40 g for a 70-kg patient). The actual dietary intake averaged 0.55 g protein/kg and 27 kcal/kg according to repeated 7-day dietary recordings. After a 6-week baseline period on this diet, all patients received additionally 0.112 g EAA/kg for 6 weeks followed by a double-blind crossover study of 0.105 g alpha-KA/kg versus placebo supplementation for 6 weeks each. Fasting blood samples for multiple parameters, including 15 indicators for protein deficiency, as well as anthropometric and clinical data were evaluated every 3 weeks. Laboratory data revealed no indications of protein deficiency. Therapy with alpha-KA diminished serum phosphate concentration (p less than 0.05), however no other significant beneficial effects could be demonstrated during supplementation with either EAA or alpha-KA. Therefore, such supplementation to a 0.55-g/kg-protein diet appears superfluous in stable ambulatory patients with renal insufficiency.

Adolescent↗
PubMed1982

Analysis of survival of end-stage renal disease patients.

Traditional life-table analysis of differences in patient survival for various end-stage renal disease (ESRD) treatment modalities ignore the fact the ESRD patients face sequential risks because they frequently experience more than one mode of therapy. A modification of the usual life-table analysis is suggested as being more appropriate. This modified method takes into account the "time-to-treatment" bias, which, in this instance, is the time spent on the first modality of treatment (that is, center dialysis). The survival data of more than 2,000 ESRD patients in the State of Michigan during the 5-year period, 1974 to 1978, are used to illustrate this method.

Adolescent↗
PubMed1981

In vivo studies of dialysis-related endotoxemia and bacteremia.

The transfer of bacteria and endotoxin and the development of fever was monitored during hemodialysis of dogs. Bacterial and endotoxin levels in dialysis fluids exceeded those reportedly associated with pyrogenic reactions, and bacteria-free dialysate filtrates administered intravenously were shown to be pyrogenic in 2 of 2 dogs. During 18 hollow-fiber dialyses, neither bacteria nor endotoxin, as measured in the Limulus lysate assay (LLA), was detected in venous and arterial blood samples. Body temperatures did not increase during or within 1/2 h after dialysis. In experiments with parallel dialyzers, contaminated dialysate was simultaneously ultrafiltered into the second blood compartment. Ultrafiltrates were unreactive in the LLA and the absence of pyrogens was confirmed with the pyrogen test, USP, in five of five experiments. This investigation suggests that the intact cellophane membrane of the hollow-fiber dialyzer is an effective barrier to endotoxin and bacteria.

Animals↗
PubMed1980

Absence of bacteremia and endotoxemia despite contaminated dialyzate.

Fevers associated with hemodialysis have been attributed to the transfer of relatively large endotoxin molecules and/or bacteria from contaminated dialyzate across the dialyzing membrane. We evaluated 27 patients during hollow-fiber dialysis when, due to a malfunction, dialysis fluids contained bacteria and endotoxin at levels previously reported to be associated with pyrogenic reactions. Neither endotoxin nor bacteria was detected in 54 venous and arterial blood specimens collected at the termination of hemodialysis. Temperature elevations did not occur during or within 1/2 hr after dialysis. In an extended study, 20 dialyzers were collected after single patient use and the dialyzate compartment was filled with highly contaminated dialyzate, while the blood compartment was filled with sterile pyrogen-free saline. Following 5 to 7 days incubation, bacteria were present in the blood compartments of 4 of 20 dialyzers, probably due to contamination during dialyzer handling. However, the much smaller endotoxin molecule could not be detected in the absence of bacterial contamination. These results indicate that the intact cellophane membrane is an effective barrier to endotoxin and bacteria under clinical conditions.

Endotoxins↗
PubMed1979

Bacterial and endotoxin permeability of hemodialysis membranes.

Dialysis fluids containing at least 10(7) bacteria per milliliter and as much as 12,500 ng of endotoxin equivalents per milliliter were dialyzed and ultrafiltered with three types of disposable hemodialyzers. Neither bacteria nor endotoxin, as measured by the Limulus lysate assay, was detected in the sterile compartment despite ultrafiltration. Under these favorable conditions for endotoxin transfer, the maximum transfer rate was calculated to be less than 3.5 ng of endotoxin equivalents per hour. At this rate, it is unlikely that pyrexia during hemodialysis is due to the transfer of endotoxin across an intact dialyzing membrane. Provided that the integrity of the dialyzing membrane is maintained, this investigation indicates that the risk of endotoxemia or bacteremia associated with the use of contaminated dialysis fluids is negligible.

Bacterial Infections↗
PubMed1979

Preventing hemorrhage in high-risk hemodialysis: regional versus low-dose heparin.

Hemodialysis in patients with increased risk for hemorrhage can be accomplished with either a regional or a low, total dose of heparin. In a prospective study of 69 series of dialyses performed on an alternating schedule of heparinization for each patient, bleeding complications during and immediately following dialysis occurred in 23 of 122 dialyses (19%) with regional heparin compared to 13 of 133 dialyses (10%) with low-dose heparin (P less than 0.05). The incidence of hemorrhage correlated with the estimated degree of bleeding risk both at expected and at occult bleeding sites, and was the same or higher with regional heparin in all categories. Hemorrhage was not correlated with preexisting coagulation abnormalities, concurrent anticoagulant drugs, level of azotemia, or ability to successfully limit systemic heparinization during dialysis. The incidence of partial clotting of the dialyzer was 3 to 5% with both heparin protocols. We conclude that regional heparinization has no clinical or practical advantage over low-total-dose heparin in preventing bleeding associated with hemodialysis.

Hemorrhage↗
PubMed1978

Effect of acetate administration on blood lipids.

An infusion of 180 mEq sodium acetate was given to nine dialysis patients and eight normal volunteers simulating the transfer of acetate that occurs during 30 min of rapid hemodialysis. While serum acetate concentrations had almost normalized 15 min after the end of infusion, there was no increase in serum cholesterol and triglyceride concentrations. In this short-term study, acetate does not appear to be a major contributing factor for the hyperlipidemia of dialysis patients.

Acetates↗
PubMed1978

Hemodialysis and schizophrenia. A negative report.

A preliminary, uncontrolled study utilizing hemodialysis in the treatment of chronic schizophrenia reported a high success rate. Two patients are presented who had both schizophrenia and chronic renal failure and who underwent intensive, long term hemodialysis with no change in their schizophrenic symptomatology. This negative finding is consistent with other case reports. Retrospective or limited controlled studies based on previous research with false neurotransmitters, serum protein factors, or endorphins in schizophrenia are urged before further patients with normal kidney function are exposed to the risks of hemodialysis.

Adult↗