PubMed Health⌕ Search

SEARCH · PubMed Health

Results for “Urinary Calculi”

Explore indexed PubMed citations for clinical trials, systematic reviews and public health research. Read source abstracts and follow each citation to its original PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 19 recordsLinked to original sources
PubMed1977

Excretion of 4-pyridoxic acid and oxalic acid in patients with urinary calculi.

Urinary excretion of 4-pyridoxic acid and oxalic acid was investigated in 75 patients with urinary calculi and in 50 normal subjects on regular diet. Mean excretion of 4-pyridoxic acid was 0.85 and 0.90 mg per day, respectively, and mean excretion of oxalic acid was 27.5 and 28.0 mg per day, respectively. Statistically there was no difference between the two groups in 4-pyridoxic acid excretion or in oxalic acid excretion. There was a weak positive correlation between the urinary excretion of 4-pyridoxic acid and oxalic acid. Patients who were on ascorbic acid supplementation during the urine collection period excreted increased amounts of oxalic acid. It was concluded from this investigation that most patients with urinary calculi had 4-pyridoxic acid excretion and oxalic acid excretion within normal limits. Low 4-pyridoxic acid values were not combined with high excretion values of oxalic acid, and the nutritional state of vitamin B6 in patients with urinary calculi was assumed to be satisfactory in order to control the endogenous oxalic acid production. The significance of high excretion values of 4-pyridoxic acid and oxalic acid is discussed.

Ascorbic Acid↗
PubMed1976

A contribution to the formation mechanism of calcium oxalate urinary calculi. I. Stabilising urinary constituents in the formation of weddellite.

25 to 30% of calcium oxalate urinary calculi consist of the metastable Weddellite crystal phase. By fractionation of urine it was found that mineral substances are stabilising factors. The stability was checked in dry condition at room temperature at 38 degrees C and at 110 degrees C. These results could be confirmed by precipitation from synthetic solutions. Mg, Zn, Ni, Co, Mn and Cu individually, and above all in combination, promote the formation of Weddellite. The formation of mixed crystal phases must be considered one of the main factors for the stabilisation of Weddelite in the urinaty calculus.

Calcium↗
PubMed1979

Unusual aspects of urinary calculi in children.

Urinary calculous disease is unusual in children in the United States. During the last 5 years (1972 to 1977) we have examined and treated 35 children with urinary calculi. The predisposing factors to calculus formation have been established in 20 children. Metabolic screening, although mandatory, has proved unrewarding in the evaluation of children with urinary calculi. Obstructive uropathy, immobilization, urinary stasis and infection, previously undiagnosed urologic anomalies, steroid therapy, milk-alkali syndrome, iatrogenic disease and endemic disease have contributed to stone formation. The management of children with urinary calculi generally parallels that of adults but reflects a need for caution when performing transurethral extraction of lower ureteral calculi. Reduction in dairy product intake, fluid diuresis and frequent changes in position may provide adequate prophylaxis against urinary calculi in children who must be immobilized.

Adolescent↗
PubMed1976

A contribution to the formation mechanism of calcium oxalate urinary calculi. II. In vitro experiments concerning the theory of the formation of Whewellite and Weddellite urinary calculi.

In vitro investigations of the formation of Whewellite or Weddellite are described. By means of different precipitation models the influence of cationic minerals on the formation of Weddellite could be observed. The possible conversion of Weddellite into Whewellite in vivo is demonstrated by in vitro experiments. A theory of the formation of Weddellite or Whewellite urinary calculi is developed on the basis of the results obtained.

Calcium↗
PubMed1979

[Experiences with instrumental methods for urinary calculi analysis].

To reduce the urinary calculi incidence by calculi formers, it is important to know the composition of these stones. Unfortunately the chemical analysis does not give very reliable results. Looking for a better method to analyse urinary calculi, three instrumental methods were tested: infared spectroscopy, thermal analysis and X-ray diffraction. The experimental results and economical considerations show that the X-ray diffraction analysis of urinary calculi would meet the goal of improved care of patients with stones.

Humans↗
PubMed1977

Infrared spectrometric analysis of urinary calculi.

The composition of urinary calculi was studied by means of infrared spectroscopy. Analysis of 150 calculi has shown that their infrared spectrum offers quick and reliable results and the method helps to plan the therapy. Organization of a central laboratory for calculus analysis is recommended.

Apatites↗
PubMed1979

[Compliance and active cooperation of patients in preventing recurrence of urinary calculi].

An anonymous questioning of 200 patients with urinary calculi concerning the observation of the general and special measures of the metaphylaxis of urinary calculi resulted in the fact that in particular the measures of the general metaphylaxis (bodily movement, diet, dilution of the urine) are not or only parlty obeyed by a large part of the patients. The examinations show that for the improvement of the understanding of the disease and the behaviour of the patients concerning their health further on a great attension must be paid to the quality of the information by the physician and to the communication between physician and patient. An insufficient cooperation of the patients in the metaphylaxis of the urinary calculi would call in question the effectivity of all efforts and measures concerning the prevention of relapses.

Adolescent↗
PubMed1975

[Microscopic investigation of the partial stages of dissolution processes in urinary calculi (author's transl)].

The formation of urinary calculi cannot yet be prevented with certainty. Consequently the dissolution of stones remains a focus of medical interest. The speed of solution of a calculus is not a quantity typical of the substance, but depends largely on the structural formation of the urinary calculi. With very different types of structure (e.g. Whewellite and Weddellite stones) the rate of dissolution can therefore fluctuate between wide limits in spite of similar phase composition. Consequently, type of structure, course of solution and rate of solution can be clearly correlated. Stones with relatively uniform structure formation (e.g. Struvite stones) on the other hand show largely similar solution rates. Medically, it is of interest that in certain structural types, solution may lead to disintegration of the stone into isolated solution residues.

Solubility↗
PubMed1978

Ultrastructure and pathogenesis of human urinary calculi.

The ultrastructure of human urinary calculi was studied using scanning and transmission electron microscopy. The hydroxyapatite constituent of the stones was often present in the form of sperical aggregates of the minute apatite crystallites (1 to 10 mu in diameter). In most cases, the sperical apatite deposits consisted of concentric lamellae of crystallites. The spherical apatite deposits, described in detail for the first time in urolithiasis, were similar to those found in a variety of calcified tissues including nephrocalcinosis and malakoplakia.

Apatites↗
PubMed1978

[Variations in the use of microscopic instruments for the examination of urinary calculi in routine professional practice and in research].

Generalising considerations concerning the problem of the analysis of urinary calculi as well as a longer testing within own examination prove modern microscopic methods and devices to be a scientific and practical instrumentarium for the examination of urinary calculi which has a good future. Expensive special microscopes may above all remained reserved for research examinations on urinary calculi, if simple laboratory microscopes for routine analyses of urinary calculi are supplemented by cheap additional constructing elements.

Germany, East↗
PubMedDate not supplied

In vitro destruction of urinary calculi by laser-induced stress waves.

A new, nonsurgical technique is proposed for the destruction of urinary calculi. This technique exploits recent advances in laser-fusion research in the generation of shock waves from high-intensity pulsed lasers and the principles evolved from extensive military research on fragmentation resulting from the interactions of shock waves on solids. In the in vitro experiments reported here, stress waves were generated by irradiating a thin film confined between glass and metal substrates with a high-intensity pulsed laser. It was shown that a nominal 2-J, Q-switched Ruby or Nd-glass laser is easily capable of producing stress waves of up to 10-kbar peak pressure and that the rise time of the stress pulse is on the order of the laser pulse duration. Urinary calculi (kidney or bladder stones) of different sizes, shapes, colors, hardnesses, and composition were fragmented by laser-induced shock waves into sizes quite capable of being passed spontaneously. Critical laser parameters have been determined, and the associated threshold pressure for the destruction of the hardest types of urinary stones has been measured. The possible application of this technique to in situ destruction of urinary calculi is described.

Acoustics↗
PubMed1979

Composition of apatites in human urinary calculi.

Calcium-deficient carbonate apatites in urinary calculi from 17 patients have been studied. Magnesium ions in each case were detected as a component of apatite. In most of the cases, CO23- ions were included in the apatitic lattice. Using a calcination procedure, we have determined the most probable average value for the CO23- content, degree of deficiency, x, and the Mg/Ca ratio in each sample.

Apatites↗
PubMed1976

Clinical features and treatment of urinary calculi in childhood.

During the period 1926-1975, 94 children with urinary calculi were treated. The incidence, causation, localisation, symptomatology and diagnosis of urolithiasis in children are discussed. The therapeutic possibilities are also outlined. Particular emphasis is laid on therapeutic programmes for the prevention of recurrence in all varieties of urinary calculi, by means of which the recurrence rate in our own series was reduced to around 16%.

Adolescent↗
PubMed1978

Cytological changes due to urinary calculi: a consideration of the relationship between calculi and the development of urothelial carcinoma.

Urinary calculi can induce urothelial cellular abnormalities comparable with those of malignancy; this was found in 11 out of 62 lithiasis cases. Severe cellular changes, comparable with those of carcinoma in situ, may be seen in the epithelium adjacent to a calculus. Squamous metaplasia was frequently observed in cases with staghorn stones in the renal pelvis. The abrasive effect of the calculus may result in many multinucleated cells in the sediment. When the calculi are removed the cytological atypia and the observed multinucleation disappeared, and none of these 62 patients developed urothelial carcinoma. A possible relationship was found between a long-term clinical history of lithiasis and the development of cancer of the upper urinary tract in a study of 92 cases of carcinoma of the ureter and renal pelvis.

Cytodiagnosis↗
PubMed1978

Studies in urolithiasis. III. Electron optical investigation on the morphology of the colloidal matrix of urinary calculi.

An electron optical investigation of the morphology of the colloidal matrix of renal and vesical urinary calculi revealed the presence of several morphologic forms hitherto unknown. Earlier light microscopic studies indicated that the matrix exists either as fibrils or as an amorphous matrix. The electron micrographic scanning of specimens of calculi revealed the following matrix morphologies: (i) flaky, (ii) serrated, (iii) perforated (globular), (iv) hollow tubular, (v) fibrillar, (vi) cylindrical, and (vii) pear-drop shaped. Crystalline matter was not associated with flaky and serrated matrix particles. However, some matrix particles of perforated (globular), fibrillar, and cylindrical morphologies were found to be calcified.

Humans↗
PubMed1976

The determination of silicates in urinary calculi.

The determination of silica and silicates in urinary calculi is rendered difficult by the common occurrence in such material of high concentrations of calcium, magnesium and orthophosphate. The problem has been studied, and manual and semi-automated procedures for the determination are described. 145 stones from the urinary tracts of patients with spinal cord injury were analysed, but in all of them the silicon content was below the limit of detection of 0.7 gSiO2 per 100 g calculus.

Autoanalysis↗