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Biomedical subjects

H A Lee

Publications and source records attributed to H A Lee.

At least 19 recordsLinked to original sources
PubMed1991

Uraemia: is urea more important than we think?

Urea is accumulated as an osmolyte by some groups of animals even though it impairs protein function. These organisms can withstand high internal urea concentrations because they also accumulate other low-molecular-weight osmolytes, the methylamines, which can offset the effects of urea on proteins. Methylamines have also been found in the medulla of the mammalian kidney (where urea concentrations are high) and in the plasma of human subjects with chronic renal failure. These findings suggest that previous investigations of the potential contribution of urea to the syndrome of uraemia may have been confounded because of the presence of variable concentrations of protective substances. That naturally occurring methylamines or related substances may prove to have a useful therapeutic role in uraemia is also possible.

Animals↗
PubMed1991

Nuclear magnetic resonance studies of blood plasma and urine from subjects with chronic renal failure: identification of trimethylamine-N-oxide.

We have used 1H-, 13C- and 14N-NMR spectroscopy to investigate the constituents of plasma and urine in 16 patients with chronic renal failure (CRF). Resonances not previously observed in spectra of plasma from healthy volunteers were seen in CRF plasma, including those for trimethylamine-N-oxide (TMAO) and dimethylamine (DMA). A possible analogy with the plasma of elasmobranch fishes, in which TMAO stabilizes proteins in the presence of very high urea concentrations, is noted. The intensity of the TMAO resonance for CRF subjects was correlated with the plasma concentration of urea (R = 0.55) and creatinine (R = 0.74), suggesting that the presence of TMAO is closely related to the degree of renal failure. When normal subjects ate a meal of TMAO-containing fish, TMAO appeared rapidly in the plasma and in the urine. Thus TMAO is efficiently cleared by the healthy kidney. Differences in the interaction of lactate with plasma proteins were detected by NMR, suggesting that uraemia impairs their transport roles.

Adult↗
PubMed1991

Sub-optimal doses of human recombinant erythropoietin markedly lower serum ferritin.

Human recombinant erythropoietin in full dose substantially raises the haemoglobin in patients with end stage renal disease on dialysis. In lower doses no or little rise in haemoglobin is achieved but the ferritin, often very high before treatment, is disproportionately lowered. The hormone therefore may be useful in reducing iron overload in other situations.

Anemia↗
PubMed1990

Azathioprine and allopurinol: a potentially dangerous combination.

We report the association of leucopenia and anaemia in five patients given a combination of azathioprine and allopurinol. Three subjects were renal transplant recipients with mild to moderate impairment of graft function. The complication appeared between 4 and 6 weeks following initiation of the combination therapy. Discontinuation of one of the two drugs resulted in full recovery within 4-8 weeks.

Adolescent↗
PubMed1990

Bartter's syndrome and diabetes mellitus.

We here report a case of Bartter's syndrome occurring in association with diabetes mellitus. The patient, an insulin-dependent diabetic, presented with hypokalaemia, inappropriate kaliuresis and metabolic alkalosis. He had high plasma renin activity, relatively low plasma aldosterone, and resistance to infused angiotensin II. A high potassium diet raised total body potassium and serum potassium, did not affect plasma renin activity, but raised plasma aldosterone significantly and did not alter the resistance to angiotensin II. Indomethacin administered acutely reduced urinary potassium and kallikrein excretion and, on chronic administration, lowered plasma renin activity, urinary chloride excretion, and raised serum potassium. Salt restriction resulted in a prompt and significant reduction in urinary sodium and chloride excretion. Urinary kallikrein excretion was very high throughout, increased with sodium restriction, and decreased with sodium loading. Oral potassium supplementation partially corrected the hypokalaemia, but did not affect blood sugar control. In this patient the primary defect appears to have been primary urinary potassium wasting, rather than sodium or chloride wasting. The striking effects of indomethacin suggest that prostaglandins may play a fundamental role in the genesis of the syndrome.

Adult↗
PubMed1990

Enzyme-linked immunosorbent assay for Salmonella typhimurium in food: feasibility of 1-day Salmonella detection.

A microtitration plate, antibody-capture, enzyme-linked immunosorbent assay was developed for detection of Salmonella typhimurium. The assay utilizes a monoclonal detector antibody which shows no cross-reactions with non-Salmonella species and only a slight cross-reaction with one other Salmonella serotype. By using only one cultural stage (in a nonselective, chemically defined medium) prior to the enzyme-linked immunosorbent assay, low numbers of cells in food (10 cells 25 g-1) were detected in 19 h. Non-Salmonella competing organisms did not interfere with detection of S. typhimurium even when present in the ratio of 10(6):1 (non-Salmonella/Salmonella spp.). The assay shows the feasibility of rapid, 1-day testing for Salmonella spp. with antibody technology.

Antibodies, Monoclonal↗
PubMed1979

Prevention of amino acid losses during peritoneal dialysis.

The addition of amino acid supplements to peritoneal dialysis fluid has been studied in 8 patients with compromised renal function requiring peritoneal dialysis. By the addition of 10 ml of Vamin-glucose solution to each one litre of peritoneal dialysate, amino acid losses were curtailed, no significant alterations occurred in the plasma amino acid concentrations, there were no local complications and no infections were seen. This procedure is recommended as a safe, simple way of keeping a patient in positive amino acid balance during peritoneal dialysis.

Amino Acids↗
PubMed1979

Evaluation of a high nitrogen source amino acid solution ('Aminofusin' L Forte).

A new high concentration nitrogen source solution ('Aminofusin' L Forte) was evaluated in 9 patients requiring complete parenteral nutrition regimens. Excellent clinical tolerance was observed and the solution proved capable of maintaining patients in nitrogen balance. Although the non-essential part of the amino acid profile is incomplete, no significant deviations from the normal range in plasma amino acid concentrations were noted. It is concluded that the solution is a useful addition to the range of amino acid preparations available for intravenous feeding.

Adult↗
PubMed1979

Principles of intravenous nutrition.

In my view intravenous feeding represents a substantial advance in the management of critically ill patients. It is no longer tenable that patients should die as a result of complications of malnutrition simply because they cannot or are unable to take adequate oral nutrition. Intravenous feeding is a challenge both in concept and application. With it, however, the outcome for many patients, who formerly would have died, has considerably improved.

Anthropometry↗
PubMed1979

The role of plasmapheresis in renal transplantation.

Plasmapheresis has been studied in ten patients who received cadaveric renal allografts. In six patients (group A), plasma was carried out on the first post-operative day and then on alternate days until six treatments had been completed. No beneficial effect was observed but treatment was well tolerated and there were no complications. One patient retains a functioning graft. Plasma exchange was carried out on six consecutive days in five patients (group B) who were actively rejecting their grafts and in whom conventional methods of treatment had failed. All five patients showed improvement in graft function. Rejection was reversed in four patients and was contained in one patient. Subsequently rapid recrudescence of graft rejection occurred in one patient, extended graft survival was seen in two patients, and the other two patients have retained life supporting grafts. Plasmapheresis may have a part to play in the treatment of renal allograft rejection and further evaluation of this treatment is indicated.

Antibodies↗
PubMed1979

The use of tienilic acid in nephrotic syndrome: a clinical study.

The diuretic and uricosuric activities of tienilic acid 250--50 mg daily over a minimum six week period have been studied in seven patients with the nephrotic syndrome secondary to glomerulonephritis proven by renal biopsy. Tienilic acid failed to control oedema in one patient who had to be withdrawn. In the six other patients a hypouricaemic effect with increased urate clearance was noted. No consistent effects were noted with respect to the serum cholesterol and triglyceride concentrations. No side effects were observed. It is concluded that in nephrotic patients tienilic acid behaves as a mild diuretic with consistent hypouricaemic and uricosuric effects.

Adolescent↗
PubMed1978

Hypercalcemia and hypophosphatemia in a mare with renal insufficiency.

An 11-year-old mare with polyuria, polydipsia, and azotemia was found to be hypercalcemic and hypophosphatemic. The concentration of calcium in a single collection of urine was within normal limits, although urinary inorganic phosphate concentration was lower than normal. After a brief period of supportive treatment, the mare died. At necropsy, the kidneys were found to be shrunken and fibrous. Histologically, the lesions were those of glomerulonephritis.

Animals↗