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Biomedical subjects

G A Rose

Publications and source records attributed to G A Rose.

At least 73 records · Page 4Linked to original sources
PubMed1982

Tamm-Horsfall mucoproteins promote calcium oxalate crystal formation in urine: quantitative studies.

The technique of rapid evaporation of whole urine to standard osmolality has been studied further and quantitative measurements made of the calcium oxalate crystals resulting, firstly by a microscope method and secondly by isotope method using 14C-oxalate. It is confirmed that ultrafiltration of urine prior to evaporation leads to a large reduction in calcium oxalate crystal formation and that this is largely restored by addition of human urinary Tamm-Horsfall protein (uromucoid). Albumin does not have this effect.

Albumins↗
PubMed1982

Magnesium reduces calcium oxalate crystal formation in human whole urine.

1. A low urinary magnesium was induced in normal volunteer subjects by giving cellulose phosphate; magnesium was added in vitro to yield urine samples of normal and high magnesium concentrations. 2. After rapid evaporation of these urine samples at pH 5.3 to standard osmolality the calcium oxalate crystals were measured by microscopy and isotopic methods. 3. There was a clear inverse correlation between magnesium concentration and calcium oxalate crystal formation. 4. The case for treating calcium oxalate urolithiasis with magnesium is strengthened.

Calcium Oxalate↗
PubMed1982

Urate does not influence the formation of calcium oxalate crystals in whole human urine at pH 5.3.

1. Samples of fresh human urine were treated with immobilized uricase to lower urate concentration. Urate was added to yield low, normal and high urate samples. 2. Each sample was rapidly evaporated at pH 5.3 to standard osmolality and the yield of calcium oxalate crystals measured either by semi-quantitative microscopy or fully quantitative radioisotope techniques. 3. Increase of urinary urate did not increase the calcium oxalate crystals formed and may even have had an opposite effect. 4. Allantoin was without significant effect upon calcium oxalate crystal formation. 5. These data provide no support for the suggestion that reducing urate concentrations in the urine may be of value in treatment of patients with calcium oxalate stones.

Allantoin↗
PubMed1982

Oxalosis in infancy.

We describe 3 infants with nephrocalcinosis and terminal renal failure. In all 3 there was widespread oxalate deposition: biochemical evidence of primary hyperoxaluria was sought but the presence of severe renal failure and the lack of established normal values for urinary and plasma oxalate and glycollate in infants made this diagnosis difficult to establish.

Calcium Metabolism Disorders↗
PubMed1981

Urine composition in normal subjects after oral ingestion of oxalate-rich foods.

1. Urinary composition was studied in nine healthy adults on unrestricted diet and low-oxalate diet with and without individual oxalate-rich foods. 2. Urine oxalate was constant on the low-oxalate and constant high-oxalate diets and only fluctuated greatly on unrestricted diet. 3. Urine oxalate was mainly due to dietary oxalate which accounts for up to two-thirds of urinary oxalate. 4. Urine oxalate was unaffected by urine volume. 5. Varying percentages of dietary oxalate were absorbed depending on the nature of the foodstuff. 6. Although tea was the main source of dietary oxalate in some people it, like strawberries, did not represent a real risk factor. Chocolates, peanuts, beetroot, rhubarb and spinach were considered as high-risk foods. 7. Calcium oxalate crystalluria at 4 degrees C was increased significantly when the oxalate-rich foods were taken. When urine was examined at 37 degrees C no increase in crystalluria was found.

Adult↗
PubMed1981

Hyperoxaluria following glycine irrigation for transurethral prostatectomy.

Thirty-four patients were studied following transurethral prostatectomy with glycine irrigation during and soon after the operation. Three cases developed hyponatraemia and this was accompanied by severe hyperoxaluria with raised urinary glycolate. This could be a hazard if urinary volume were allowed to fall.

Aged↗
PubMed1980

The real and apparent plasma oxalate.

A method for the determination of human plasma oxalate concentration by an enzymatic assay procedure is described using deproteinised plasma. The apparent concentration of oxalate in 20 normal subjects was 1.1--16.0 mumol/l (mean 7.78; S.D. 3.96). It was suspected that these results might be too high, due to the possible conversion of glyoxalate to oxalate, and this reaction was clearly demonstrated to occur in whole blood in vitro. Inhibitors (boric acid, DL-beta-phenyllactic acid, and allopurinol) of this oxidation were therefore added to the freshly taken blood samples, prior to assaying by the same technique. The plasma oxalate concentration from normal subjects was then found to be 0--5.4 mumol/l (mean 2.26; S.D. 1.67). It is concluded that normal blood spontaneously generates oxalate on standing, and the higher values obtained by other in vitro methods must be fallacious.

Blood Proteins↗
PubMed1980

Successful renal transplantation in primary hyperoxaluria.

A successful live related renal transplant in a 29-year-old male patient with Type 1 primary hyperoxaluria, who remains well 32 months postoperatively, is described. The plasma oxalate and exchangeable oxalate pool before transplantation were 160 mumol/1 and 4429 mumol respectively. Since the transplant these have been greatly reduced although they remain elevated above the normal by a factor of 2. Pyridoxine therapy and the avoidance of oxalate-rich foods have been effective in maintaining these reduced levels and the 24-hr urinary oxalate excretion has also been maintained close to normal levels on this regime. After review of the previously reported transplants in patients with well documented primary hyperoxaluria and from the experience with this patient, the following guidelines for successful renal transplantation in primary hyperoxaluria are suggested: transplants should only be carried out in those who have shown a response to adequate pyrodoxine therapy; frequent haemodialysis pre-operatively and during periods of oliguria postoperatively is necessary; oxalate-rich foods should be avoided and a high fluid intake should be maintained after transplantation. If these guidelines are followed there is no contra-indicatin to live related renal transplants in primary hyperoxaluric patients.

Adult↗
PubMed1980

Oxalate content of some common foods: determination by an enzymatic method.

A specific enzymatic method was used to determine the oxalate content of some common foods. No preliminary isolation of oxalate was required and recoveries ranging from 95-110 per cent were obtained. Spinach, rhubarb, peanuts, chocolates, parsley and tea were found to contain high levels of oxalate as previously described by others. On the other hand the oxalate content of beetroot was found to be five times as high as previously reported, but coca-cola and beer were almost free from oxalate. Cereals and meat were either low or deficient in oxalate.

Beverages↗
PubMed1979

A new enzymatic method for the determination of glycollate in urine and plasma.

An enzymatic assay for the measurement of glycollate in urine and plasma is described. Gycollic acid oxidase (glycollate:oxygen oxidoreductase, EC 1.1.3), extracted from spinach leaves, is used in the enzymatic oxidation of glycollate to produce glyoxylate and hydrogen peroxide. In the presence of peroxidase, the hydrogen peroxide oxidatively couples sulphonated 2,4-dichlorophenol and 4-aminophenazone to form a soluble purple quinoneimine dye. Interfering substances are removed from plasma by deproteinisation and from urine by adsorption onto activated charcoal before analysis. Glycollic acid oxidase also catalyses the oxidation of lactic acid which therefore has to be determined separately. The mean normal urinary glycollate for adults is 0.19 mmol/24 h with no difference between males and females. The mean normal plasma glycollate for adults is 0.17 mmol/l, but higher in males than in females.

Adult↗
PubMed1979

Uromucoids and urinary stone formation.

Crystal formation was studied in fresh urine samples after rapid concentration to standard osmolarity in a rotary evaporator at 37 degrees C. Uromucoids promoted calcium oxalate and calcium phosphate crystal formation and also induced clustering of calcium phosphate precipitates. It is postulated that uromucoid precipitation is the first stage in stone formation. Minerals then deposit on the uromucoid precipitate and the whole complex becomes attached to the renal tubules.

Calcium Oxalate↗