In patients surviving long time after kidney transplantation the possibility of development of malignant disease should be considered. Preventive evaluation should guarantee early detection of cancer. Appropriate treatment, without cessation of immunosuppressive therapy, is indicated with the intention to prolong the patients' life with a functional graft and without dialysis treatment.

Urinary oxalic acid excretion was determined in 21 healthy people and 70 patients with renal stones. In the group of 31 patients with calcium oxalate-containing renal stones the mean value of urinary oxalate exretion was significantly higher than both in the normals and the patients with non-oxalate renal stones. Urinary oxalate excretion above the upper limit was found in 12 patients with calcium oxalate-containing renal stones (38.7%) and in one patient with radio-paque renal stones and nephrocalcinosis. In the patients with hyperoxaluria great variability in oxalate excretion was found. There was no relationship between urinary oxalate and calcium excretion and between urinary oxalate excretion and 24-hour volume of urine. It is suggested that there is relationship between the increased urinary oxalate excretion and recurrent calcium oxalate-containing renal stones formation in the investigated group of patients.

A series of 98 children with urolithiasis is analyzed especially with regard to some diagnostic and treatment problems of the disease. The results of the study of etiology, clinical features, associated diseases and metabolic disorders in this series are presented. Urinary stasis, urinary infection and metabolic disorders were found to be very frequent in children with kidney stones and are considered to be the main causes of stone formation.Urolithiasis has been shown to be a serious problem in Czechoslovakia. Mates and Kfi~ek [15] reported its occurrence in 1 per cent of population. The etiology of urolithiasis is so far not fully understood. Anomalies of the urinary tract with stasis of urine, metabolic disorders, long-term immobilization, urinary tract infections, alterations in the mechanism of protective colloids and vitamin A deficiency have been found to be the most frequent factors which promote the, formation of stones within the renal pelvis.Particularities of the infantile urolithiasis consist of the known geographic nonhomogeneity of its occurrence and of the greater number of anomalies of the excretory kidney pathways, by which urolithiasis is often accompanied. To be simultaneously solved, the anomalies require recognition before the operation of calculi.Also infantile urolithiasis is not uncommon in our country. Bedrna [2] observed it in 1.4 per cent of all lithiases, Kafka [11 ] in 20 per cent of infantile patients with urologic diseases. In Kukula's [12] group of 422 selected patients its incidence was 36 per cent in children. Elefant et al. [6] observed 160 children with urolithiasis, 17 of whom were younger than 1 year. Zvara et al. [22] selected 868 adults and 31 children with urolithiasis during 3 years. The number of children thus represented is 3.5 per cent. Kukula [12] elaborated the first extended study of the incidence of urinary stones in Bohemia. The first mention about infantile urolithiasis in Slovakia was found in Bdkay's [3 ] study, where the material from the past Austrian-Hungarian monarchy is summarized. In these older works bladder calculi are predominantly described. Kukula [12J included in his study only cystolithiases, Bdkay [3] found that of 1836 selected patients 1319 had cystolithiasis, 9 nephrolithiasis and 508 ureterolithiasis. Urology and Nephrology I, 1969

Urinary excretion of vitamin C was investigated in 44 patients with chronic renal diseases and in 25 patients after renal transplantation with various mean glomerular filtration rates. In both groups a hyperbolic relationship was observed between FE vitamin C and CCr. In addition, direct relationships were found between FE vitamin C and FE Na, FEK and FE H2O in both groups. Various chronic renal diseases and treatments had no influence on the investigated relationships. In 16 healthy subjects urinary excretion of sodium during maximal water diuresis did not increase but urinary excretion of vitamin C significantly increased. In 10 patients in the polyuric stage of chronic renal failure without dialysis treatment during Giordano-Giovanetti-Maggiora diet with addition of sodium chloride the urinary excretion of sodium increased but that of vitamin C was not influenced. The results obtained for the biochemical parameters tested suggest that the urinary excretion of vitamin C depends on the urinary excretion of water.

In a group of 57 children with urolithiasis hypomagnesaemia was found in 15 cases (26.3%). All children but one with abnormally low serum magnesium levels had recurrent or bilateral nephrolithiasis or nephrocalcinosis. Prevalence of hyperoxaluria and hypercalciuria, marked severity of the clinical features, abnormality of Ca metabolism and its responsiveness to MgO treatment were demonstrable in Mg deficiency.

Hypomagnesemia, hypocalcemia and hypophosphatemia after renal transplantation in an 18-year-old patient is described. Serum magnesium decreased in consequence of increased renal transplant function with high urinary magnesium excretion. At the time of serum magnesium depletion, pretransplantation hypocalcemia persisted and severe hypophosphatemia developed. Magnesium oxide treatment was followed by the increment not only in serum magnesium but also in serum calcium and phosphate to normal level. Causal relationship between magnesium deficit and impaired renal transplant tubular reabsorption of magnesium and between magnesium deficit and serum calcium and phosphate depletion in the patient is suggested.

Urinary zinc, calcium, creatinine and osmolar excretion per 24 hours was measured in 21 healthy subjects and 49 patients with urolithiasis. Urinary zinc excretion in kidney-stone formers was lower than in healthy subjects, but the difference was not statistically significant. In healthy subjects, there was a normal relationship between urinary zinc excretion and urine volume, creatinine and osmolar excretion, which was not found, with some exceptions, in the groups of patients. There was no relationship between urinary zinc and calcium excretion in healthy subjects or in patients with normocalciuria or hypercalciuria. A possible role of relative hypozincuria in kidney-stone formation in patients with hypercalciuria and/or hyperoxaluria is suggested.

An epidemiological and clinical study of a sample of 105 children with urolithiasis treated in the period 1965–1974 in a defined population of children revealed a decrease in the rate of incidence of this disease in a municipal infant population with high-ranking care for their health. Serious forms of urolithiasis are on the decrease. There is a higher rate of incidence in schoolboys and schoolgirls, the latter being more often involved than boys. Despite the general lower rate of occurrence, urolithiasis still has such forms as will endanger the life of the organ and the life of the patient. Injury to health of the child by this disease consists mainly in loss of one kidney, ambilateral staghorn stones that proved irremovable in their entirety and pyelonephritis.