Calculi


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Calculi

 

(also concretions or stones), solid masses in the hollow organs and glandular ducts of man.

Calculi may be of different sizes, shapes, and consistencies. The chemical composition varies with the place where they are formed and with the composition of the fluid in which lithogenesis (formation of stones) takes place. Calculi in the gall bladder and bile ducts consist of cholesterol, bile pigments, calcium phosphate, and calcium carbonate; urinary calculi are formed in the urinary tract and are divided according to the acid radicals into urates (the commonest type), oxalates, phosphates, and carbonates. Urinary calculi may contain xanthine, cystine, indigo, sulfur, soap, and cholesterol. The causes of calculi formation may be general (for example, disturbance of metabolism or pregnancy) or local (change in the chemical composition of a secretion, specifically, its protective colloids and pH, stagnation of a secretion, inflammation). Lithogenesis is most often caused by a combination of these factors. The formation of biliary and urinary calculi is the basis of cholelithiasis and urolithiasis, respectively.

References in periodicals archive ?
The first urologic use of the holmium laser dates to 1993 when ureteric calculi were treated by laser vaporization.
The proposition is illustrated in Figure 2, which shows calculi S and T and the images [S.sup.*], [T.sup.#], [S.sup.*#], and [T.sup.#*] of these calculi under maps * and #.
The signs and symptoms of renal calculi are similar to those of a urinary-tract infection.
Whatever mathematical models are studied, I believe that process calculi provide an essential perspective for the study.
Conclusion: Combining visual standard channel with F4.8 visual puncture SMP for the treatment of multiple renal calculi had the advantages of reducing the number of large channels, high rate of stone clearance, safety and reliability and mild complications.
So, to evaluate the efficacy and safety of mini-PCNL in proximal ureteral calculi and renal calculus we started this hospital-based study (January 2018- November 2018) to use mini-PCNL (15F semi-rigid nephroscope via a 18-Fr percutaneous tract) for the treatment of proximal ureteral calculi (from PUJ to lower border of L4 vertebra) and renal calculi of [less than or equal to]20 mm.
Conclusion: Both surgical approaches had high clearance rates of multiple renal calculi, safety, reliability and few complications.
Thus, we designed a study to determine the potential role of AEI-High MI mode in the diagnosis of urinary calculi.
Direct light absorption of the urinary calculi increases the temperature of the irradiated volume above the ablation threshold, consequently causing the ejection of fragmented breakdown products.
He endorsed a history of prostatic calculi requiring surgical intervention as a teenager.
Salivary calculi consist primarily of calcium phosphate, carbonate hydroxyapatite in combination with an organic matrix of glycoproteins, and mucopolysaccharides.