The problem of urolithiasis is not a simple one for many kinds of stones are known which probably require different conditions for their nucleation and growth. Calculi are found in the kidneys, ureters, bladder and urethra and for those not resulting from any anatomical abnormality, there is no proven reason why growth should occur in say the upper urinary tract as opposed to the lower. Nevertheless, the results of many epidemiological studies (see, for example, references in review articles such as Andersen, 1969) have shown the existence of well-defined zones in the world in which either upper or lower urinary tract stones predominate. Bladder stones in children and adults are a problem in certain areas of technically developing countries like India and Thailand, while kidney stones in adults constitute most of the calculi from industrialised countries. Some possibly indirect connection between these 2 broad categories is, however, likely, for in certain countries of intermediate economic development, both varieties are found, usually but not always in different areas, and the distribution of upper and lower urinary tract stones in them is again dependent on the extent and duration of "industrialisation" present. There is also evidence that bladder stones were a problem in parts of Great Britain, Northern Ireland and Northern Europe prior to this century but they died out about 50 to 60 years ago and have been succeeded by kidney stones. Conditions which have led or are leading to the disappearance of one kind probably then favour the formation of the other.Stones also differ widely in composition. Many compounds can crystallise in them and frequently several are present in one calculus, but the importance of each constituent, as judged by its frequency of occurrence in collections of stones, varies considerably. In a geographical and historical investigation of the composition of urinary calculi, we have studied representative collections of stones from different countries and found that a few constituents, not always the same, predominate in each but that there is an overall similarity in the total amount of some of the constituents in collections comparable with respect to the variables already mentioned, namely the patient's age, the site of the stone in the urinary tract and the extent of economic development in the geographical area concerned (Sutor, 1972).We have now extended this work using a computer to group together comparable collections of stones and then to derive data on the patients and the calculi in each subdivision. This we hope will lead to a better understanding of the different types of urolithiasis as revealed by our study of stone composition, and demonstrate their distribution past and present on a geographical basis. Material and MethodsCollections of urinary calculi from the following countries, cities and institutions are included in this study: Czechoslovakia (99 stones), Eire (69) England (656 stones from 10 cities), India (176 stones from 2 centres), Kuwait (67) Northern Ireland (...
Very few prostatic calculi have been analysed by the X-ray powder method, a technique which gives the exact nature of the crystalline material present and not, as in chemical analysis, a jumble of ions which are often impossible or difficult to relate. Huggins and Bear (1944) studied 2 true prostatic stones using this method, found the chief constituent was the same as that of bone, but wrongly reported it as being tricalcium phosphate instead of apatite probably because of the confusion existing then over the composition of the different calcium phosphates. No other crystalline material was found. Over the last 7 years, we have received 28 prostatic calculi for analysis by X-ray diffraction. The results are summarised here since they show the presence of a calcium phosphate not previously reported in prostatic calculi as well as providing the first comprehensive X-ray analysis of this type of stone. Material and MethodThe stones ranged in weight from 0.004 to 22.5 g and came from patients whose ages ranged from 30 to 92 years. They were analysed using the techniques described in an earlier paper (Lonsdale, Sutor and Wooley, 1968).
Summary In a collection of 856 urinary calculi from Great Britain and Northern Ireland, the most abundant and frequently occurring crystalline constituents are the mono‐ and di‐hydrates of calcium oxalate and hydroxy‐ and carbonate‐apatite. On the basis of composition, most stones can be assigned to a few well‐defined groups. The most common composition type, accounting for 34% of the collection, is that composed of calcium oxalate+calcium phosphate. The oxalate can be either or both of the hydrates, often both are present, but the calcium phosphate is generally hydroxyapatite. Stones consisting of pure calcium oxalate make up 27% of the total, while those comprised of struvite+calcium phosphate contribute 17%. In the latter variety the calcium phosphate is almost invariably carbonate‐apatite. The other group considered consists of the pure calcium phosphate calculi which account for 7% of the collection. The incidence of stones in relation to their site in the urinary tract and the patient's age and sex has been investigated, together with the effect of the stone site, patient's age and sex on the distribution of calculi in the main composition groups and the effect of composition, site, age and sex on the stone weight. Most of these variables have a significant effect on one another. The incidence of stones is also related to daily occupation, professional workers being 10 times more likely to develop urolithiasis than labourers. We thank the Medical Research Council and Nuffield Foundation who financed most of this work and Mr D. Sturt who kindly agreed to the participation of the Computer Centre in this project. We are greatly indebted to Mr N. W. Please for advice and many helpful discussions on the statistics and for carrying out the analysis of variance. Finally, we are grateful to the many surgeons and physicians who provided the stones and the data.
A gallstone of almost perfect octahedral symmetry was composed of a mixture of crystallites of the three polymorphous forms of calcium carbonate: calcite, aragonite, and vaterite.
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