Abstract: A solid ceramic composition comprising &bgr;-TCP, hydroxy apatite and a substantial amount of &agr;-TCP as shown in the x-ray diffraction spectrum, which is useful as a bone graft substitute. A process for preparing the composition by subjecting a mixture of ionic calcium, phosphate, aspartic acid and carbonate to microwave irradiation and quenching the irradiated mixture.

Abstract: There is provided an assay for determining the propensity of a person to develop a certain type of kidney stones which is based on the inter-action of the urine of such a person with aqueous solutions of compounds which interact to form such stones. The number and size distribution of resulting particles is determined and the results are evaluated. There is further provided a device for carrying out such an assay, comprising means for interacting the urine of the patient with two solutions containing compounds which form kidney stones, means for breaking up crystal aggregates and means for passing a light beam through the sample positioned in a transparent container, and means for determining the number and size of the resulting particles.

Abstract: A method is provided for diagnosing a patient's proneness to develop kidney tones of the calcium oxalate type, which comprises forming an aqueous reaction medium comprising from about 5 to about 20% by volume of a sample of the patient's urine, said medium having an ionic strength of from about 0.01 to about 0.1 and containing calcium ions at a concentration of from about 1 to about 5 mM/l and oxalate ions at a concentration of from about 1 to about 7 mM/l; measuring by means of a calcium ion-specific electrode the rate of decrease of the calcium ion concentration and comparing the thus measured rate with the corresponding rate determined with a reference sample of normal urine. A kit for carrying out the above method is also provided.