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At least 19 recordsLinked to original sources
PubMed1979

Scanning electron microscopy of human prostatic corpora amylacea and corpora calculi, and prostatic calculi.

Ultrastructural studies of human prostatic corpora amylacea and corpora calculi, and prostatic calculi were conducted in order to delineate their etiology and pathogenesis. Scanning electron microscopy was employed in conjunction with histology and transmission electron microscopy in the study of prostatic tissues and concretions obtained from 21 individuals. Results confirmed that desquamated acinar cells contribute to the formation and growth of corpora amylacea. A variation in density of the matrix of the matrix of the corpora produces a laminated structure. The deposition of hydroxyapatite crystallites in corpora amylacea leads to the formation of corpora calculi. Further growth and mineralization of corpora calculi lead to the development of the more clinically significant prostatic calculi. Small spherical aggregates (from 0.5 to 5 micron in diameter) of hydroxyapatite crystallites are a prevalent constituent of the corpora and prostatic calculi. Similar spherical aggregates of hydroxyapatite crystallites have also been identified in urinary calculi and other pathologic tissues suggesting similar mechanisms of mineral precipitation.

Calculi↗
PubMed1976

A contribution to the formation mechanism of calcium oxalate urinary calculi. III. On the role of magnesium in the formation of oxalate calculi.

The influence of magnesium in vitro on the precipitation of calcium oxalate was investigated. Even at maximum physiological magnesium concentrations a litholytic effect could not be observed, but the retardation of the calcium oxalate crystallization caused by magnesium might be decisive for a reduction in calculi formation. The enlargement of the calcium oxalate crystals and aggregates caused by the retardation of crystallization, however, should be regarded as a contraindicating factor for Mg therapy in oxalate calculous disease. It is safe to say that high magnesium concentrations prevent the conversion into Whewellite of the calcium oxalate calculi substance primarily formed as Weddellite.

Calcium↗
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↗
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↗
PubMed1978

Effects of ethylenediaminetetraacetic acid-4 sodium solution on the surface of renal calculi and the uroepithelium.

Tetrasodium ethylenediaminetetraacetic acid is one of the most effective agents that dissolve renal calculi, especially calculi containing calcium. To study the dissolving process of calculi in solutions, with or without trypsin, serial thin sections of renal calculi composed of calcium oxalate and/or phosphate were prepared and observed by polarizing microscopy. The effects of the solution on the surface of human renal calculi and rat uroepithelium also were studied by scanning electron microscopy. A remarkable difference in solubility was noted between the crystalline and the amorphous components in struvite calculi. Under the polarizing microscope the dissolving effect of 5 per cent tetrasodium ethylenediaminetetraacetic acid solution on struvite after 30 minutes of incubation was equivalent to the use of saline for 24 hours. The effect of trypsin was not apparent. However, under the scanning electron microscope trypsin accelerated the dissolving effect of the tetrasodium ethylenediaminetetraacetic acid solution in struvite and calcium oxalate calculi. The contradictory findings of the ineffectiveness of trypsin on the thin sections as opposed to the pronounced changes seen on the surface of the calculi could be attributed to the difference in the exposed area. The results suggest that trypsin does not seem to dissolve calculi but mainly facilitates the solution to permeate the calculi. The cellular arrangement of the uroepithelium was preserved in tetrasodium solution and in 0.04 per cent trypsin tetrasodium ethylenediaminetetraacetic acid solution.

Animals↗
PubMed1992

Electromagnetic extracorporeal shock wave lithotripsy for calculi in horseshoe kidneys.

Between June 1987 and January 1991, 11 renal units in 10 patients with horseshoe kidneys were managed by electromagnetic extracorporeal shock wave lithotripsy (ESWL) monotherapy with a Siemens Lithostar. A total of 33 calculi was treated in 42 sessions. All treatments were performed without anesthesia and on an outpatient basis. All calculi could be targeted by standard installation techniques. The maximum number of shock waves per session was 4,000, which implies per stone an average of 1.3 sessions and an average of 4,903 shock waves (range 1,800 to 9,000) at a mean energy setting of 17.8 kv. Complete disintegration or fragmentation into spontaneously passable particles was achieved in 27 calculi, for a success rate of 83% when considering the results in regard to the individual stone locations. Per renal unit, an average of 3 calculi were targeted and after an average of 3.8 sessions 6 units became stone-free. Horseshoe kidneys, when calculous, contain dispersed and multiple calculi and from these data approximately 1 session per stone must be planned. The number of treatments per renal unit increased in proportion to the number of calculi and to the presence of calculi with low fragility. Of 21 lower pole calculi 18 completely evacuated and this observation has been related to the more medial location of the inferior calices near the ureteropelvic junction. No impaired drainage of fragments was noted to be related to the horseshoe anatomy. Patency of the ureteropelvic anatomy appeared to be the main parameter for the evacuation of fragments. Neither preoperative nor postoperative adjuvant maneuvers have been necessary.

Adult↗
PubMed1975

Morphology of salivary calculi. The distribution of the inorganic component.

Different hypotheses concerning the pathogenesis of salivary calculi have been postulated on the basis of their morphology. In the present study, microradiography of plane-polished ground sections of a number of salivary calculi has shown that the morphology of salivary calculi varies considerably. The commonly accepted concept that salivary calculi emanate from an inorganic nucleus, which then successively grows by the apposition of alternating shells of organic and inorganic substances, could not be established by this study, as the microradiographs show that the distribution of mineral elements varied extensively from one calculus to another. Thus, whereas some calculi exhibited a lamellar structure, others consisted largely of homogeneous, irregular layers of alternatively high and low mineral content. The lamellar structure also showed great variation, extending in some cases over the entire diameter of the calculus. Some calculi lacked the lamination in their peripheral parts whereas, in others, lamination occurred only in the most peripheral zone. The structure of the central portions also showed a varied configuration. The calculi were often built up around one or more mineralized nuclei, often centrally located, while in some cases a mineralized nucleus was lacking. This report discusses some of the significant factors in the great variation in morphological features and therefore also in the pathogenesis of salivary calculi.

Humans↗
PubMed1975

An observation on the composition and recurrence of urinary calculi.

Seven hundred patients with 735 urinary calculi were studied for the compositions of calculi by infrared analysis and for stone recurrence. Of these 700 cases, 422 cases were possible to follow up, and 250 cases have had no further stone; 138 cases experience recurring stones, and 34 cases had multiple stones. The length of follow-up period was 1-19 years averaging 8 years, 8 months. 41.2% of patients with calcium oxalate-calcium phosphate calculi had stones recurrently, and although there was some variation of recurrence rates for patients with various proportions of oxalate to phosphate in the calculi, it was impossible to predict the tendency of recurrence by these proportions. The stone recurrence was noted in 38.6% of patients with magnesium ammonium phosphate calculi, in 38.9% with mixed magnesium ammonium phosphate-calcium oxalate calculi, in 55.6% with uric acid calculi, and in 50% with cystine calculi.

Adolescent↗