Calcium salts of ketoacids as a new treatment strategy for uremic hyperphosphatemia.

Hyperphosphatemia and secondary hyperparathyroidism are regular complications in patients suffering from end-stage renal failure. Aluminum-containing drugs are widely used to control serum phosphate, but this therapy carries the well-known risk of aluminum toxicity. Previously we demonstrated that a mixture of ketoacids is very effective in lowering increased serum phosphate and serum PTH levels. Recent studies to clarify the underlying mechanisms whereby these compounds lower serum phosphate revealed that ketoacids act as intestinal phosphate binders. In balance studies we demonstrated that intestinal phosphorus uptake decreased in normal subjects (decrease of absorption during ingestion: 0.7-3.14 mmol/day). Additional in vitro studies not only confirmed the in vivo results but also showed that ketoacids are as efficient as calcium carbonate although they provide less calcium. It is of further interest that ketoacids reached their greatest binding efficiency when the pH is 7.0, whereas calcium carbonate binds phosphate predominantly when the pH is 2.0 or 5.0. Ketoacids represent a further therapy to lower serum phosphate in uremia. As they provide less calcium than calcium carbonate, they could be considered as an advantageous, less dangerous alternative.

The beneficial effect of ketoacids on serum phosphate and parathyroid hormone in patients with chronic uremia.

Hyperphosphatemia and secondary hyperparathyroidism are regular complications in patients suffering from advanced renal failure. As aluminum-containing drugs carry the well-known risk of aluminum intoxication, we were interested in testing in a prospective study a mixture of ketoanalogues and amino acids which have been shown to lower the serum phosphate and parathyroid hormone in uremic patients. For 3 months, in addition to their diet, 17 uremic patients and 12 hemodialysis patients received a daily supplement of this mixture. Although no additional phosphate binders were administered, serum phosphate decreased significantly in the former group and was slightly lower in the latter. The serum parathyroid hormone level was consistently lowered when the initial concentration was not higher than 20 times normal.

Failure to show a correlation between serum parathyroid hormone, nerve conduction velocity and serum lipids in hemodialysis patients.

The proposed role of parathyroid hormone as an important agent for the development of certain uremic complications could not be confirmed in studies correlating, in dialysis patients, the nerve conduction velocity and the serum lipids with four different immunochemically defined forms of circulating parathyroid hormone. To a certain extent the data invalidate suggestions which favor parathyroid hormone as a leading uremic toxin.

Failure to show a temperature-dependent vascular stability during hemofiltration.

The effect of different blood temperatures on the vascular stability during hemofiltration was evaluated in 10 patients being in the regular chronic hemofiltration program. In contrast to recent data, no differences could be observed with regard to the heart rate, systolic blood pressure or mean arterial pressure, when the blood returned to the patient either with a temperature of 34.68 degrees C or 36.22 degrees C. According to these data it is therefore presently not justified to consider differences in the blood temperature as a critical determinant for the vascular stability during HF.

Unintentional weight loss in chronic hemodialysis patients--a diagnostic dilemma.

Reasons for an unintentional weight loss were investigated in a retrospective study of 26 (13.5%) patients who, out of 192 patients, had revealed a continuous linear weight loss of more than 4 kg since commencing hemodialysis treatment. The investigated serum parameters were not indicative, nor were the regularly performed tuberculin tests and the computer tomography helpful for the diagnosis. However, from the analysis of the causes for hospital admission it appears that hemodialysis patients with wasting suffer especially frequently from a sepsis. Physicians should be aware of this complication which induces further body weight loss.

The occurrence of fever during hemodialysis and hemofiltration. A comparative study.

The occurrence of fever during various blood purification methods was evaluated in a retrospective study. It could be demonstrated, that patients treated chronically by conventional hemodialysis experience six times more febrile episodes than patients on chronic hemofiltration (4.84% versus 0.81%). Since many of the increased temperatures could not be explained by conventional means, it has to be assumed that the treatment itself caused the fever, possibly activating the monocyte hormone interleukin 1. It is of further note that there was no difference in the magnitude of the temperature due to septicaemia or to no obvious cause. This finding necessitates in our opinion an early antibiotic therapy in those cases where fever develops without clear explanation.

The influence of the calcium/phosphorus ratio in the diet on human bone disease, the role of nutritive secondary hyperparathyroidism.

60 out of 100 patients suffering from severe periodontal disease received a daily calcium supplementation of 1,000 or 2,000 mg during a period of 9 or 12 months. Different investigations such as PTH and serum parameters were not influenced by this treatment. However, animal experiments, as well as acute studies in men involving an oral phosphorus load, suggest that parathyroid secretion might be increased by a lowered calcium/phosphorus ratio. Therefore it is possible that a diet too low in calcium could contribute to the pathogenesis of periodontal disease. The lacking effect of calcium therapy implies very strongly that other factors are more important for the development of this disorder.

The very elderly dialysis patient: indication and discontinuation of dialysis.

1. When the current available data in the literature is summarized it becomes evident that the majority of it supports the position that it is, at least for medical reasons, not advisable to exclude patients over the age of 80 years from chronic dialysis. 2. It is correct to say that the refusal of dialysis therapy for elderly dialysis patients would lead to a not insignificant cutting of costs, although elderly patients are not as 'expensive' as younger dialysis patients. 3. The decision to exclude patients over 80 from dialysis treatment is difficult, in our opinion, to support ethically. 4. The refusal of therapy by a dialysis patient--independent of his age--can only occur with his/her consent, as long as the patient is clearly conscious of the decision. 5. Should the patient no longer be in the condition to exercise his/her autonomy, and there is no AD, the Surrogate's Court must be consulted. 6. AD can be seen as helpful, since they not only make the decisions for physicians easier, but also because they can be seen as an act of care for family members. 7. Whenever dialysis therapy is discontinued the problematic nature of so-called essential care should be carefully considered, especially if no clear position has been taken in an AD.

[Vitamin D 1980--a stocktaking (author's transl)]. / Vitamin D 1980--Eine Bestandsaufnahme.

Vitamin D3 and its various metabolites have a central position in the regulation of the calcium- and phosphorus metabolism. Of special importance is 1,25-dihydroxyvitamin D3, which is almost exclusively synthesized in the kidney. Its production is dependent upon several hormonal stimuli and of course occurs normally only in intact renal tissue. The multifactorial regulation of its formation implies that a variety of diseases could cause disturbances in the metabolism of vitamin D. 1,25-dihydroxyvitamin D3 exerts its biological effects not only at the intestine, bone and kidney, but as well presumably in organs as the parathyroid glands, hypophysis, pancreas and skin. 24,25-dihydroxyvitamin D3--although its biological value is still in debate--represents possibly a second vitamin D-hormone of importance. Inspite of intensive research work the metabolic fate of vitamin D3 and its full biological significance is not yet entirely understood.

Dietary treatment as seen by German nephrologists. Results of a questionnaire.

The majority of German nephrologists consider a protein restriction for patients with advanced renal failure as necessary. However, there was no consensus with regard to the diet, which should be finally applied. It was of further interest that the majority of physicians believe that only 50% of their patients adhere consistently to the diet.

Treatment of uremic hyperphosphatemia--is there still a need for aluminum salts?

Aluminum-containing phosphate binders have been widely employed in the past in the management of uremic hyperphosphatemia. However, an increasing number of reports on aluminum toxicity has stimulated efforts to replace this therapy by safer methods. The aim of the present review is to critically evaluate other treatment strategies. It appears that aluminum-containing phosphate binders should no longer be considered the treatment of choice for controlling uremic hyperphosphatemia. Calcium carbonate, calcium citrate, magnesium carbonate and a mixture of ketoanalogues and amino acids present important therapeutical alternatives which could replace aluminum-containing phosphate binders in the majority of patients. However, it is mandatory, as these therapies also carry some risks, that side effects are detected early.

HTLV-III antibodies in hemodialysis patients--a consequence of blood transfusions?

An investigation for HTLV-III antibodies in chronic hemodialysis patients revealed in four out of 276 patients a positive result using the ELISA and western blot techniques. All HTLV-III positive patients had received blood transfusions. As it has been shown that a needle stick could transmit the HTLV-III, it is suggested that hemodialysis patients who have received frequent blood transfusions should be screened.

Hypercalcemia and elevated serum 1,25-dihydroxyvitamin D3 in a patient with Hodgkin's lymphoma.

A 74-year-old woman was hospitalized because of decreased appetite, fatigue, and weight loss. The laboratory examination revealed hypercalcemia, a slightly increased serum creatinine level, and a markedly elevated serum level of 1,25-dihydroxyvitamin D3. The most important finding the physical examination revealed was enlarged inguinal lymph nodes. A biopsy disclosed lymphocyte-depleted Hodgkin's disease. After steroids, but not after calcitonin, both the elevated calcitriol concentration and serum calcium normalized. In spite of intensive chemotherapy, a further episode with hypercalcemia occurred and increased 1,25-dihydroxyvitamin D3 serum levels were observed. According to the available evidence it seems probable that the humoral hypercalcemia in this patient resulted from production of 1,25-dihydroxyvitamin D3 in the tumor.