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Biomedical subjects

W G Robertson

Publications and source records attributed to W G Robertson.

At least 55 records · Page 3Linked to original sources
PubMed1983

Studies on the prevalence and epidemiology of urinary stone disease in men in Leeds.

A postal survey among 2% of men in Leeds showed that the prevalence of urinary stone disease is 3.8%. The prevalence of upper urinary tract and spontaneously passed stones increases progressively from 0.7% in social class 5 to 5.0% in social class 1 but that of bladder stones (0.7% in the group as a whole) is independent of social class. There is an initial peak of upper urinary tract and spontaneously passed stones commencing at age 20 and having a projected prevalence at age 90 of 5.7% and a second peak of bladder stones, commencing about age 50, with a projected prevalence of 1.9%. The prevalence of stone disease increases according to the order: single less than divorced/separated less than married less than widowed men. A family history of stones tends to be higher amongst relatives of stone-formers than amongst the corresponding relatives of control subjects, the male/female ratio being 2:1. The occurrence of urinary stones is significantly associated with that of gallstones, high blood pressure, backache, arthritis and gout but not with that of peptic ulcer, diabetes, thyroid disease or bronchitis.

Adult↗
PubMed1983

Polyanionic inhibitors of calcium oxalate crystal agglomeration in urine.

The excretions and relative potencies of various macromolecular inhibitors of the crystallisation of calcium oxalate (CaOx) were measured in the urines of idiopathic calcium stone-formers and normal subjects. The stone-formers excreted significantly less polyanionic macromolecules in their urine than did the normals, the difference being attributable to the lower excretions of glycosaminoglycans (GAGS), ribonucleic acid (RNA) and Tamm-Horsfall mucoprotein (THM), all of which are precipitable with alcian blue. The relative potencies of the various inhibitors measured under 'whole urine equivalent' conditions using a batch crystallisation system, showed that the order of inhibitory activity towards CaOx crystal agglomeration was RNA greater than GAGS greater than THM greater than pyrophosphate (PPi). This paralleled the order of ability of these inhibitors to produce a high negative zeta potential on the surface of CaOx crystals.

Adult↗
PubMed1982

The determination of oxalate in urine and urinary calculi by a new ion-chromatographic technique.

A new method is described for the measurement of oxalate in urine and urinary calculi using medium pressure ion-chromatography. The technique is simple, requires minimal sample preparation and only 20 min analysis time. The minimum detection limit for oxalate is 0.5 mumol/l in the diluted sample as applied to the analyser. The intra-run coefficient of variation for the chromatography stage alone is 3.8%. The overall intra-run and inter-run coefficients of variation, including the sampling and dilution of urine, are 6.5 and 8.3% respectively. The method compares well with an established colorimetric technique for the analysis of oxalate both in urine and in urinary calculi.

Chromatography, Ion Exchange↗
PubMed1982

A comparison of the effects of lactose and of two chemically modified waxy maize starches on mineral metabolism in the rat.

Diets containing 30% by weight of waxy maize starch, lactose monohydrate, acetylated distarch phosphate (EEC No. 1414) or acetylated distarch adipate (EEC No. 1422) were fed to weanling female Specified Pathogen-Free Sprague-Dawley rats for 1 yr and to similar 9-month-old rats for 34 wk. Behaviour and general health were unaffected by the different diets and there were no diet-related differences in food consumption. AT the end of the experiment with 9-month-old rats the mean body weight of the animals receiving lactose was significantly lower than that of the controls receiving starch. The animals receiving the modified starches were slightly but not significantly heavier than the controls at the end of both experiments. The main treatment-related changes in rats on the three test diets were (1) caecal enlargement, (2) increased urinary excretion of calcium, (3) increased renal calcification as measured by chemical analysis of renal tissue obtained at autopsy and (4) increased medullary and pelvic nephrocalcinosis as assessed histopathologically. Acetylated distarch adipate had a slightly greater effect on the above parameters than acetylated distarch phosphate but both modified starches had less effect than lactose. The calcium content of the kidneys, as measured by chemical analysis or histopathology, increased with age, even in the animals receiving the control diet. This change may be due to excessively high concentrations of calcium and phosphorus in all the diets, including the control diet. Cortico-medullary mineral deposits were not a feature in these studies possibly because the diets were not deficient in magnesium. The importance of correct dietary formulation in long-term toxicity studies is emphasized.

Animals↗
PubMed1982

Phosphate treatment of recurrent calcium stone disease.

A group of 38 male recurrent idiopathic calcium stone formers were treated with oral supplements of orthophosphate (1 g phosphorus extra in the diet per day) and followed at intervals up to 4 years. The urinary excretion of calcium decreased (p less than 0.001) and that of inorganic phosphate increased (p less than 0.001) during treatment. These changes resulted in a small decrease in the supersaturation of urine with respect to calcium oxalate, sufficient to reduce the percentage of urines which exceeded the upper limit of solubility of that salt, and a small increase in the supersaturation of urine with respect to calcium phosphate. The stone episode rate on treatment fell in 35 of the 38 patients from a mean pretreatment value of 0.66 episodes/year to 0.22 episodes/year. The 3 initially most prolific stone formers increased their rate of stone formation during treatment. Plasma biochemistry showed no evidence of parathyroid stimulation.

Calcium Oxalate↗
PubMed1982

The pattern of urinary stone disease in Leeds and in the United Kingdom in relation to animal protein intake during the period 1960-1980.

Studies on the occurrence of urinary stone disease in Leeds between 1960 and 1980 show that there was an increase in the number of stones formed during the period 1960-1970, a fall between 1972 and a subsequent rise between 1977 and 1980. The fluctuations in stone incidence were accounted for almost entirely by changes in the number of 'pure' calcium oxalate stones and, to a lesser extent, the number of uric acid stones produced. The incidence patterns of these types of stone closely reflected changes in the consumption of animal protein in the population as a whole during the same period. There were no parallel changes either in the number of stones consisting of a mixture of calcium oxalate and calcium phosphate or in the number of infection stones.

Dietary Proteins↗
PubMed1982

Prevalence of urinary stone disease in vegetarians.

A study was carried out to determine the effect of a low animal protein diet, such as taken by vegetarians, on the risk of urinary stone disease. A nation-wide survey of vegetarians in the UK showed that the prevalence of urinary stone formation is 40-60% of that predicted for a group of individuals taken from the general population and matched for age, sex and social class with the vegetarians. The findings support the hypothesis that a diet low in animal protein reduces the risk of urinary stone formation.

Adult↗
PubMed1981

Effect of intestinal surgery on the risk of urinary stone formation.

The prevalence of urinary stone disease in 426 patients who had undergone bowel surgery at the General Infirmary at Leeds from 1958 to 1978 was found by postal questionnaire to be 9.4%. The risk of urinary stone formation was determined from the composition of 24 hour urines from 61 unselected patients, in whom intestinal resections had been performed. There were 27 patients with an ileostomy, 17 patients with an ileostomy and a small bowel resection, and 17 patients with a small bowel resection, or bypass, and an intact colon. Of this group of 61 patients, 9.8% gave a history of urinary stones after surgery. Compared with normal control subjects ileostomy patients had significantly lower urinary pH and volume, higher concentrations of calcium, oxalate, and uric acid, and increased risk of forming uric acid and calcium stones: a small bowel resection combined with an ileostomy increased the ileostomy output, lowered the urinary volume further, and reduced urinary calcium excretion. The concentration of urinary oxalate increased and the risk of both uric acid and calcium stones was high. Patients with small bowel resection and intact colon had hyperoxaluria and an increased risk of calcium stones despite a low urinary calcium. There was no increased risk of uric acid stones in this sub-group. It is concluded that the risk of forming urinary stones after this type of surgery is considerable. The follow-up of patients with ileostomies and with small bowel resections should include an assessment of faecal losses and urinary composition to identify the patients who have a high risk of forming urinary stones.

Adult↗
PubMed1981

Ionized calcium in body fluids.

This article will review the methods currently available to the clinician and research worker for measuring the concentration of ionized calcium in various body fluids including whole blood, serum, plasma, urine, cerebrospinal fluid, milk, and synovial fluid. The methods to be reviewed are based on procedures involving bioluminescence, colorimetry and ion-selective electrodes. Emphasis will be given to the precision and, wherever possible, accuracy of each technique. Possible sources of error and interfering agents will be identified. Attention will be given to the recommended conditions for measuring ionized calcium in each body fluid. An assessment will be made of the theoretical and practical importance of measuring ionized calcium rather than total calcium and of its value in clinical medicine.

Adult↗
PubMed1980

Effects of pyrophosphate and diphosphonates on the dissolution of hydroxyapatites using a flow system.

Pyrophosphate and diphosphonate ions have been said to diminish the dissolution of hydroxyapatite crystals, because they lower the equilibrium concentrations of calcium and phosphate ions in the bulk solution around hydroxyapatite crystals in a closed system. However, in a closed system these effects are not necessarily due to an effect on dissolution alone. In this paper we have used a continuous flow system to study the effects of pyrophosphate and two diphosphonates, ethane-1-hydroxy-1,1,-diphosphonate and dichloromethane diphosphonate, on the dissolution of hydroxyapatite. All three compounds decreased markedly the rate of dissolution of hydroxyapatite as well as the exchangeable pools of calcium and phosphate ions around the crystals.

Calcium↗
PubMed1980

The cause of idiopathic calcium stone disease: hypercalciuria or hyperoxaluria?

Hypercalciuria is common in patients who form calcium oxalate urinary stones and is considered by many to be the cause of the disorder. This review shows that there is little relationship between either the rate of stone-formation or calcium oxalate crystalluria and the urinary excretion of calcium. There is, however, a strong relationship between these parameters and the urinary excretion of oxalate which is slightly, but significantly, elevated in stone-formers compared with normals. It is concluded that this mind degree of hyperoxaluria may be much more important than hypercalciuria in the genesis of calcium oxalate stones.

Calcium↗
PubMed1980

Clinical and metabolic aspects of urinary stone disease in Leeds.

In summary, the persistent passage of urine excessively supersaturated with calcium oxalate and/or calcium phosphate in conjunction with a low level of inhibitory activity increases the risk of abnormal crystalluria and stones in a given individual. Treatment of the disorder must be aimed at correcting the abnormal risk factor(s) in that individual.

Adolescent↗