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Biomedical subjects

J A Sargent

Publications and source records attributed to J A Sargent.

At least 37 records · Page 2Linked to original sources
PubMed1981

Modeling of middle molecules in clinical studies.

1. Peptides 7f and 7g may be irreversible metabolic and products generated into and confined in a volume approximating extracellular fluid. 2. The concentration profiles reported for 7a, 7b, and 7c suggest they are metabolic intermediates and that complex metabolic upsets are induced by dialysis resulting in marked sequential acceleration of generation and removal. These compounds cannot be modeled at present. 3. In steady state 7f and 7g might be described by the function G = KrC + KmC; while 7a, 7b, and 7c would likely require a more complex function such as G(C,beta) = KrC + KmC.

Humans↗
PubMed1979

Mass balance: a quantitative guide to clinical nutritional therapy. I. The predialysis patient with renal disease.

Mass balance principles can be readily applied to the patient with chronic renal failure for the more structured management of his/her nutritional and clinical course. Urine values provide valuable information with respect to rates of protein catabolism and sodium intake; creatinine excretion rates provide a ready check on data accuracy and lean body mass; urea and creatinine clearance can be calculated, if blood levels of these solutes are known. With accurate data on creatinine generation and the ratio of urea to creatinine clearance, creatinine clearance, urea generation, and protein catabolism rates can be estimated from blood levels alone. These techniques then provide quantitative guidance for the nutritional/medical staff in its efforts to control the clinical course of the patient with severly diminished renal function.

Acute Kidney Injury↗
PubMed1979

Mass balance: a quantitative guide to clinical nutritional therapy. II. The dialyzed patient.

The concepts of mass balance are extended to the nutritional management of the patient with chronic renal failure on dialysis. The use of these concepts permits estimation of protein catabolism from calculated rates of urea generation, using measurement of blood urea levels. Protein catabolic rate will equal intake in the stable patient (zero nitrogen balance), allowing for accurate nutritional screening in a large dialysis population for whom these values are available without individual dietary surveys. This has resulted in a four-fold reduction in routine monitoring of protein nutrition in such patients, freeing the dietitian to concentrate on specific problems. These concepts also comprise a key aspect of the National Cooperative Dialysis Study which seeks to maintain BUN at different levels in four carefully controlled modes of dialysis therapy. With these methods, the monitoring and control of BUN and protein intake has made the dietitian a pivotal member of this study staff.

Blood Urea Nitrogen↗
PubMed1978

Nitrogen balance during intermittent dialysis therapy of uremia.

Daily measurements of nitrogen balance were made at two levels of protein intake in five patients undergoing chronic intermittent dialysis therapy. During ingestion of high (1.4 g/kg of body wt) protein intake, nitrogen balance was positive on nondialysis days and negative on dialysis days, so that cumulative balance for the week of study was not different from zero. During ingestion of low (0.5 g/kg) protein intake, nitrogen balance was approximately zero on nondialysis days but was again negative on dialysis days, so that cumulative balance for this period was negative. The negative nitrogen balance observed on dialysis days was associated with a higher rate of urea nitrogen generation (Gu, g/24 hr, determined by a kinetic model of urea nitrogen in dialysis patients) that was most evident in the hours immediately following dialysis. Net protein catabolic rate (PCR, g/24 hr), derived from total nitrogen mass balance equations, correlated very closely with Gu:Gu = 0.154 PCR - 1.7, r = 0.96. This relationship agreed well with previous observations made in nondialyzed uremic patients under more steady-state conditions. These studies demonstrate that nitrogen balance is negative on dialysis days regardless of protein intake, and that Gu is higher on dialysis days. The negative nitrogen balance could result from amino acid loss in dialysate and from increased protein catabolism stimulated by loss of glucose into dialysate.

Adult↗
PubMed1978

A theoretical definition of minimal acceptable dialysis therapy.

A theoretical definition of "minimal acceptable dialysis therapy" is that which: provides optimal sodium, potassium, hydrogen, and water homeostasis, optimal calcium and phosphorus homeostasis, and nontoxic concentration profiles for all other solutes which exhibit concentration-dependent toxicity normally controlled by renal excretion; results in maximal patient well-being and rehabilitation with minimal dialysis related morbidity; is sufficiently well-defined with respect to dose to be reliably prescribed for any individual patient which requires that, for all solutes of clinical importance, the kinetic behavior and closure of mass balance be verified for individual patients. Empirically, the minimum dose of dialysis (dialyzer urea clearance, treatment time and frequency) sufficient to result in mean predialysis BUN values of 80 mg/dl with documented dietary protein intake (DPI) greater than or equal to 1.0 g/kg/day and measured protein catabolic rate (PCR) equal to DPI has been shown to be acceptable with respect to currently achieved clinical outcome parameters.

Humans↗
PubMed1977

Nutritional implications of renal disease. II. The dietitian's key role in studies of dialysis therapy.

As research develops better dialysis techniques, the dietitian's input in the management of patients with renal disease is vital, for their protein status must be "fine tuned" with individualized treatment and counseling. Her pivotal role is being demonstrated in the National Cooperative Dialysis Study of the National Institutes of Health, one phase of which is being conducted by three hospitals in San Francisco. In that study, close monitoring of the protein catabolic rate (PCR) and blood urea nitrogen (BUN) in predialysis patients, coupled with adjustments in therapeutic dietary regimens and counseling as indicated, shows promise of bringing such patients into good control, targeted at 80+/-10 per cent bun with a PCR of 1.1+/-0.3 gm. per kilogram per 24 hr. Various dietary techniques, either singly or in combination, are being employed in an attempt to control dietary intake.

Acute Kidney Injury↗