G. Deak

Serum 25(OH)-vitamin D levels and bone metabolism in patients on maintenance hemodialysis

AIMS An increasing amount of evidence suggests that 25-hydroxy vitamin D3 (25(OH)D3) may contribute to the bone health of patients with chronic kidney disease (CKD). The underlying vitamin D status of these patients, however, has often been neglected. In a cross-sectional study we assessed the association between vitamin D status and parathyroid function, bone turnover, bone mass and structure in patients on maintenance hemodialysis. METHODS 69 patients on maintenance hemodialysis were assessed by bone densitometry (DEXA) and quantitative bone ultrasound (QUS). Serum 25-hydroxy vitamin D3 levels, serum markers of bone turnover and clinical data were tabulated. RESULTS A high prevalence of potentially significant vitamin D3 deficiency was found in this patient group: 59% of the patients had a 25(OH)D3 level below 20 nmol/l. There was a significant negative correlation between serum 25(OH)D3 levels and serum intact parathyroid hormone (iPTH) (r = -0.231, p < 0.05), and this association remained significant after controlling for potential covariables. Furthermore, we show here that serum 25(OH)D3 concentration is positively correlated with bone mineral density (BMD) measured at the radius (r = 0.424, p < 0.01). Finally, we show for the first time that 25(OH)D3 levels are significantly and independently correlated with broadband ultrasound attenuation (beta = 0.262, p < 0.05) measured with calcaneal quantitative bone ultrasound (QUS) in patients with chronic renal failure. CONCLUSION Vitamin D3 deficiency may contribute to the impaired bone health of patients on maintenance dialysis.

Description and interpretation of structural changes in canine kidneys after preservation with a hyperosmolar solution and reperfusion

The effects of hypothermic preservation of canine kidneys for 24 hours by the use of the Sacks solution, and additional autogenous reperfusion were studied by means of submicroscopic morphological methods. While preservation with the Sacks solution was to ensure normal organization of the lipoprotein structures of the basement and cell membranes, in case of additional reperfusion, even of short duration, a substantial or complete loss of anisotropy of the cytomembranes was demonstrable. The present report is the first to be published in the literature on polarization microscopic studies concerned with the effects of kidney preservation and of reperfusion.

Study of haemostasis in nephropathies associated with pulmonary haemorrhage

Three cases of pulmonary haemorrhage associated with various forms of nephropathy have been studied, and 15 laboratory tests have been carried out to analyse the observed coagulation defects. Also three kinds of capillary tests have been performed.Goodpastures syndrome. Laboratory tests pointed to hypercoagulability. Anomalies characteristic of consumption coagulopathy were observed in the terminal phase. Bleeding tendency appeared to be due to capillary damage.Lupus nephropathy. Haemorrhage of the lungs, brain, skin and eyeground was caused by thrombocytopenia.Malignant nephrosclerosis. The disease was marked by hyperfibrinogenaemia and diminished prothrombin consumption. Disturbance of thromboplastin production may have been a pathogenetic factor of the bleeding tendency.Although at least one capillary test was positive in all three cases, the coagulation studies made it probable that the pathomechanism of pulmonary haemorrhage is not the same in all nephropathies.

Study of factors affecting the antigen structure of the donor kidney. I. Interpretation of the relationship between periodate pretreatment and the rejection phenomena of canine kidney allografts.

Donor kidneys were preserved in a Collins-4 solution containing periodate in concentrations of 10−2 and 10−4 mole/l, respectively, in an attempt to oxidize the carbohydrate components of the antigen-carrying membrane surfaces and thus to influence the rejection phenomena exhibited by the allogeneic kidney. All kidneys were, however, rejected as a result of a hyperacute reaction indicating that periodate did not react with the hydrophobic membrane structuresin vivo. Not only did the antigen thus remain unchanged but the vulnerability of other renal structures to the destructive effect of the killer cells also increased as a result of toxic damage.