Diagnosis and management of renal calculous disease.
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Calcium↗
Biomedical subjects
R L Ryall
Publications and source records attributed to R L Ryall.
Measurement of urinary flow rate.
The various methods for measuring urinary flow rate from the first attempt by Rehfisch in 1897 to current techniques are described. The benefits or deficiencies of each method are considered, and it is concluded that while some of the more technically sophisticated pieces of equipment are necessary for the accurate determination of flow rates in the research laboratory, they are not necessarily the most appropriate for use in the consulting office or clinic.
Europe↗
The estimation of bladder volume by sonocystography.
Real-time ultrasonography was used to measure bladder volumes. Volumes were calculated as the product of 3 internal bladder diameters (height, width and depth). The true bladder volume was obtained from the voided volume or by catheterization. There was a good correlation between calculated and true volumes provided a correction factor of 0.6 was applied. It also was found that a simpler method using only 2 diameters and a correction factor of 0.15 was nearly as reliable. The accuracy of this quantitative method was shown to be limited to an average error of plus or minus 25 per cent for bladder volumes between 100 and 500 ml. Smaller volumes could be assessed only qualitatively. False negative readings were common for bladder volumes less than 50 ml.
Humans↗
The value of the 24-hour urine analysis in the assessment of stone-formers attending a general hospital outpatient clinic.
The daily urinary excretion of calcium, oxalate, uric acid and glycosaminoglycans, and 24-h urinary volume and pH, were measured in 39 normal men and 65 male patients who had formed at least one calcium oxalate stone. No significant difference could be found between the two groups of subjects with respect to any of the urinary parameters. Nonetheless, a higher proportion of stone-formers than normals had daily excretion levels of oxalate in excess of the normal 95th percentile. On the other hand, there was no difference between the proportion of stone-formers and normals who fell into this category with respect to calcium excretion. It was concluded that a single 24-h urine analysis is of limited practical value in explaining the occurrence of stones or in predicting the likelihood of further episodes in unselected stone-formers attending a general hospital outpatient clinic.
Adult↗
The use of urinary flow rates obtained from voided volumes less than 150 ml in the assessment of voiding ability.
The initial slope of the curve relating peak urinary flow rate to voided volume was found to predict an individual's flow rate at bladder volumes of 200 ml or more in normal subjects and those with symptoms of outflow obstruction. The numerical value of this initial slope was found to decline in a hyperbolic fashion with increasing age. A similar decrease was observed for peak urinary flow rates at bladder volumes between 200 and 300 ml. The use of initial slope as an index of voiding ability would appear to be just as effective in discriminating between normal and obstructed men as a single flow rate determination at a large volume and would be of most benefit in those patients unable to void large volumes of urine.
Adult↗
Point of view: laws of urodynamics.
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Humans↗
Medullary sponge kidney and urolithiasis.
A review of the urographic findings in 200 patients with renal colic due to urolithiasis demonstrated radiological evidence of medullary sponge kidney in 34, an incidence of 17%. In the majority, the diagnosis was readily made and the changes were bilateral and extensive. This relatively high incidence suggests that medullary sponge kidney may be a contributing factor in a population already predisposed to calculus formation because of other factors such as diet and dehydration.
Colic↗
The effect of a urethral catheter on the measurement of maximum urinary flow rate.
The maximum urinary flow rates of 147 male subjects referred for voiding difficulties were measured in the presence and absence of a fine urethral catheter. A comparison of these flow rates showed that those measured with the catheter in situ were lower than would be anticipated for the same voided volumes in the absence of a catheter. Although the reduction in flow rate caused by the catheter was only of the order of several ml./second, it was sufficient to alter the diagnostic categorisation of almost a third of the subjects classified as obstructed, unobstructed or equivocal on the basis of a plot of detrusor voiding pressure versus maximum flow rate. The effect of the urethral catheter on diagnostic classification was most pronounced in the borderline patients on whom urodynamics would usually be performed to clarify the clinical assessment. It was concluded that the routine performance of full urodynamic studies for the assessment of outflow obstruction is unwarranted.
Adolescent↗
An offive method for calibrating a uroflowmeter.
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Rheology↗
Normal peak urinary flow rates obtained from small voided volumes can provide a reliable assessment of bladder function.
The urinary flow rates of 3 normal men were measured for a wide range of bladder volumes. Linear transformation of voiding curve data indicated that the relationship between urinary flow and voided volume could be described as parabolic, hyperbolic or logarithmic. These functional relationships were found to hold irrespective of age and volume, although deviations from the calculated voiding curves occurred at higher volumes. If only voiding data for volumes less than 150 ml. were considered, then, in addition to the aforementioned mathematical relationships, the dependence of flow on volume could be described validly by a straight line function, the slope of which represents an individual's best possible voiding potential.
Adult↗
The effect of urine, pyrophosphate, citrate, magnesium and glycosaminoglycans on the growth and aggregation of calcium oxalate crystals in vitro.
The effects of pyrophosphate, citrate, magnesium, heparin and chondroitin sulphate on the growth and aggregation of calcium oxalate crystals were measured at concentrations likely to be found in 1% urine. The degrees of inhibition of growth and of aggregation caused by these compounds were related to the effects of normal 1% urine on these processes. It was concluded that chondroitin sulphate is responsible for the major portion of the inhibitory effect of urine on crystal aggregation, but that the effect on crystal growth is probably due to the additive or synergistic effects of a number of urinary constituents.
Adult↗
Interpretation of particle growth and aggregation patterns obtained from the Coulter counter: a simple theoretical model.
We used a simple theoretical model to stimulate the changes in particle size distribution that occur when crystals grow, or disaggregate to a defined extent. The change in total particle volume was used as an index of growth, whereas aggregation and disaggregation were expressed as the change in total particle number. Indices of inhibition of growth and of aggregation in hypothetical test cases were calculated in relation to a control and compared with the inhibition index derived by the standard method of comparing the distribution of particle volume around a given arbitrary diameter on the particle distribution curve. We concluded that the expression of particle growth and aggregation in terms of total volume and number respectively is a preferable alternative to the standard technique.
Calcium Oxalate↗
Independent assessment of the growth and aggregation of calcium oxalate crystals using the Coulter counter.
The growth and aggregation of calcium oxalate seed crystals in a metastable solution of this salt were assessed separately by using the Coulter counter to measure the net increase in total crystal volume and the percentage change in total crystal number respectively. The value of assessing crystal growth and aggregation in these terms was shown by using these parameters to measure the inhibitory effect of a normal human urine. Independent assessment of growth and aggregation enabled a more accurate interpretation of experimental events than was possible by considering the two processes in combination. The method therefore has the potential of improving the discrimination between the inhibitory activities of different urines.
Calcium Oxalate↗
Investigation of urinary calculi.
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Calcium↗
A reappraisal of the Coulter Counter technique for measuring calcium oxalate crystal size.
A modification of the technique for measuring crystal size using a Coulter Counter is described. The method differs from that previously published in that counts are taken at equal size increments rather than at constant threshold settings. This ensures that equal emphasis is placed on all particles, regardless of size, thereby preventing the contribution of the larger particles being artificially magnified in relation to the smaller particles as has previously been the case. A mixture of latex particles of three known sizes is used to demonstrate the improvement in resolution and accuracy afforded by the modified technique.
Crystallography↗
Developmental patterns of 3-hydroxykynurenine accumulation in white and various other eye color mutants of Drosophila melanogaster.
Several points of biochemical similarity between white and scarlet mutants suggest that both are defective in the transport of xanthommatin precursors. In both, accumulation of 3-hydroxykynurenine is negligible during larval life and occurs at only a slow rate during adult development. Larvae of both mutants also excrete 3H-3-hydroxykynurenine and 3H-kynurenine rapidly, which probably accounts for the normal levels of kynurenine during larval life. 3-Hydroxykynurenine levels are abnormal in all white mutants which were studied, although in two alleles which are strongly pigmented (w(sat) and w(col)) accumulation is enhanced rather than diminished. In w(a), larval accumulation is normal but accumulation during adult development is greatly diminished, suggesting that this mutation has a tissue-specific effect. Similar levels were found in zeste females. Of the 11 other eye color mutants tested, abnormal levels of 3-hydroxykynurenine were found in eight. In four of these (claret, light, lightoid, and pink), larval accumulation is negligible, suggesting that these have defects in the kynurenine transport system like scarlet and white. In three others, however (brown, karmoisin, and rosy), accumulation during larval life is enhanced. In cardinal accumulation is normal during larval life but is excessive during adult development. This evidence supports the suggestion that the cd mutation blocks the final step of xanthommatin synthesis.
Drosophila melanogaster↗
Glycerokinase in human adipose tissue.
The presence of glycerokinase has been demonstrated in human omental and subcutaneous adipose tissue. The enzyme reaction showed a linear time course for 5 min at 30 C and pH optima at pH 7.6 and 9.0. Saturation of the enzyme was observed at 1.8 mM adenosine triphosphate (ATP) and the double reciprocal plot of activity vs. ATP concentration was nonlinear giving two apparent Km values of 0.094 and 0.518 mM. The apparent Km for glycerol, 0.112 mM, was obtained from a linear double reciprocal plot, and the enzyme was saturated at about 0.4 mM glycerol. The activity of glycerokinase in human adipose tissue excised under general anaesthesia was low and was unrelated to adipose cell size or the degree of obesity of the subject from whom the fat was obtained.
Adenosine Triphosphate↗
The ommochrome biosynthetic pathway in Drosophila melanogaster: the head particulate phenoxazinone synthase and the developmental onset of xanthommatin synthesis.
Particulate fractions from the heads of Drosophila melanogaster catalyze the conversion of o-aminophenols to phenoxazinones. This particulate enzyme is stimulated by Mn2+. It has a number of features which distinguish it clearly from the Mn2+-dependent activity found in the soluble fraction. The particulate enzyme has a characteristic developmental pattern, showing a marked increase in activity at about the time of onset of xanthommatin synthesis. In addition, it is much reduced in activity in a number of xanthommatin-deficient mutants (v, cn, st, cd, and w). We believe that the head particulate enzyme is involved in xanthommatin biosynthesis and that the developmental onset of synthesis of this pigment is brought about by the synthesis or activation of this enzyme.
Abdomen↗