Stone formation in the Middle Eastern Gulf States: A review.

Objectives: To review the possible causes of the high incidence of urolithiasis in the oil-rich Gulf States.

Methods: Data were extracted from published reports on the incidence of urolithiasis, affluence and diet in the Gulf States, various Western countries and China.

Results: There are strong relationships: (a) between the life-expectancy of stones in men and the Gross National Income (GNI) per capita of these countries; and (b) between the daily consumption of animal protein and GNI per capita.

Methods for diagnosing the risk factors of stone formation.

Objective: To compare various systems for assessing the risk of recurrent stones, based on the composition of urine.

Methods: The relative supersaturation (RSS) of urine, the Tiselius Indices, the Robertson Risk Factor Algorithms (RRFA) and the BONN-Risk Index were compared in terms of the numbers of variables required to be measured, the ease of use of the system and the value of the information obtained.

Results: The RSS methods require up to 14 analyses in every urine sample but measure the RSS of all the main constituents of kidney stones.

Sensitization by extracellular Ca(2+) of rat P2X(5) receptor and its pharmacological properties compared with rat P2X(1).

The recombinant rat P2X(5) (rP2X(5)) receptor, a poorly understood ATP-gated ion channel, was studied under voltage-clamp conditions and compared with the better understood homomeric rP2X(1) receptor with which it may coexist in vivo. Expressed in defolliculated Xenopus laevis oocytes, rP2X(5) responded to ATP with slowly desensitizing inward currents that, for successive responses, ran down in the presence of extracellular Ca(2+) (1.8 mM).