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Biomedical subjects

K Schaefer

Publications and source records attributed to K Schaefer.

At least 73 records · Page 4Linked to original sources

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.

Administration, Oral↗

[Balloon dilatation in unstable angina pectoris and acute myocardial infarct].

Early results after percutaneous transluminal coronary angioplasty (PTCA) in patients with unstable angina or acute myocardial infarction were compared with those in patients with stable angina. The primary success rate in 115 patients with unstable angina was 72%, in 73 with acute myocardial infarction 78%, and in 213 with stable angina 79%, i.e. there was no difference between the three groups. In patients with acute myocardial infarction and primary successful PTCA control angiography was performed one month after PTCA, in patients with unstable and stable angina 6 months after PTCA. Angiographic findings were identical in the three groups. But the results after successful balloon dilatation were dependent on the extent of primary success: in all three groups, patients in whom the post-dilatation control angiography revealed recurrence of stenosis the primary results were worse than in those without. There was no difference between those patients with lasting success and those with recurrence as regards cholesterol level, arterial hypertension, diabetes, and smoking habits. It is concluded that in every patient with acute symptoms of coronary heart disease the indication for PTCA should be considered.

Angina Pectoris↗

Iron overload, but not treatment with desferrioxamine favours the development of septicemia in patients on maintenance hemodialysis.

During a 19-month period we determined the incidence of bacterial infection among 39 patients treated with desferrioxamine who had end-stage renal disease and were undergoing maintenance hemodialysis. Twenty-three received desferrioxamine because of aluminum-related bone disease, and 16 because of iron overload. A control group of 193 patients on maintenance hemodialysis but without desferrioxamine was used. No difference was found in the incidence of septicemia or of all bacterial infections between the patients with aluminum-related bone disease treated with desferrioxamine and the control patients (0.12 vs. 0.12 septicemia per patient-therapy-year, p greater than 0.05; 0.23 vs. 0.26 bacterial infections per patient-therapy-year, p greater than 0.05). The incidence of septicemia in patients treated with desferrioxamine for iron overload, however, was almost three times that in the control patients (0.36 vs. 0.12 septicemia per patient-therapy-year, p less than 0.01). To assess the effect of iron overload itself, we determined the frequency of bacterial infection in patients on regular hemodialysis who have never received desferrioxamine. These were subdivided into three groups according to serum ferritin level which indicated normal or low iron stores (Group I: serum ferritin 10-330 micrograms/l, n = 125), moderate (Group II: serum ferritin 331-1000 micrograms/l, n = 49) or more advanced iron overload (Group III: serum ferritin 1001-2000 micrograms/l, n = 10). Compared to patients with normal or low serum ferritin levels (Group I), we found a significantly higher rate of bacterial infection among patients in Group II compared with Group I (0.18 vs. 0.34 infections per patient-therapy-year, p less than 0.05) and Group III compared with Group I (0.18 vs. 0.58 infections per patient-therapy-year, p less than 0.01). These results suggest that treatment with desferrioxamine does not favour the development of septicemia or bacterial infection independently of iron overload and that iron overload itself may predispose patients on regular hemodialysis to bacterial infection.

Aged↗

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.

Aged↗

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.

Acquired Immunodeficiency Syndrome↗

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.

Aged↗

Renal osteodystrophy in asymptomatic hemodialysis patients: evidence of a sex-dependent distribution and predictive value of serum aluminum measurements.

Bone histologies and serum concentrations of calcium, phosphate, alkaline phosphatase, iPTH, 25 OHD, 1,25(OH)2D3, and aluminum were obtained from 113 chronically hemodialyzed patients free of symptoms and signs of renal osteodystrophy. All patients had a pathologic bone histology; in 69.0%, a mixed form with predominant osteitis fibrosa and concomitant osteoidosis. In 30.1%, we found pure hyperosteoidosis, nearly half of these cases showing osseous aluminum deposits. Hyperosteoidosis was much more frequent in women (35.7%) than in men (20.9%), although the prescribed intake of aluminum-containing phosphate binders was the same. It is possible that female hemodialysis patients were more prone to aluminum accumulation or that they had a better compliance in taking the aluminum hydroxide. Serum parameters alone were not very helpful in predicting the underlying bone disease. Mean iPTH concentrations tended to be lower in the patients with hyperosteoidosis than in those with the mixed lesion, but there was wide variation. Serum aluminum was only predictive for aluminum deposits in the bone when concentrations exceeded 100 micrograms/L.

Adult↗

Performance and biocompatibility of a new hemodialysis membrane.

Performance studies and investigations of the biocompatibility of a new hemodialysis membrane were conducted in patients being chronically hemodialyzed. The investigated polycarbonate membrane revealed a very satisfying performance with regard to clearance values and the ultrafiltration rate. The biocompatibility studies showed a significant leukopenia and an increase of C5a, platelet factor 4 and granulocyte elastase. Thrombocytes and C3d remained unchanged. Long-term studies have to confirm whether or not the new membrane is more biocompatible, a suggestion which could be advanced, as no febrile episodes were observed during any treatment, a finding which is not typical for Cuprophan hemodialysis.

Biocompatible Materials↗

Effect of long-term administration of 1,25-dihydroxyvitamin D3 and 1 alpha-hydroxyvitamin D3 on the calcium content of the aorta, heart and kidney of normal and uremic rats.

Studies in uremic rats were performed to see whether or not the long-term administration of therapeutical doses of 1,25-Dihydroxyvitamin D3 or 1 alpha-hydroxyvitamin D3 would induce histological changes in the aorta or increase the calcium content of the aorta or the heart. In contrast to observations of others, no effect of both vitamin D sterols could be observed on both investigated tissues. However, the remnant kidneys of the rats treated with both vitamin D compounds showed a significantly increased calcium content. According to these results one cannot exclude that the chronic application of active vitamin D metabolites has induced a calcium deposition in the remnant kidney. This finding deserves special attention, although we found, on the other hand, no evidence that an underlying arterial disease is aggravated by this therapy.

Animals↗

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.

Acute Kidney Injury↗

Effect of an acute protein load on the creatinine clearance in healthy vegetarians.

In normal man an acute protein load increases the glomerular filtration rate (GFR) significantly, which seems to represent a renal functional reserve. Healthy vegetarians are known to have a statistically reduced baseline GFR. We performed three creatinine clearance studies (24-h study design) on each of nine healthy vegetarian subjects. The first clearance was measured as baseline, the second one was done on day 2 after an oral protein load of 100 g vegetarian protein (1.2-2.0 g/kg body wt.), respectively, ingested within half an hour. The third clearance, serving as a control, was done on day 14. All subjects had their normal vegetarian meals during the study. All vegetarians had at all times a normal serum creatinine level. The mean baseline creatinine clearance was 65.4 +/- 33.3 ml/min. 1.73 m2. In five of nine vegetarians we found a significant increase of the creatinine clearance after the protein load of 66.0% (mean) and a decrease to the baseline values, respectively, when the control clearance was measured. The remaining four vegetarians did not increase their creatinine clearance immediately after the protein challenge and their control clearances were found to be significantly reduced (-40.2%) compared to the individual baseline.

Adult↗

Endotoxin-induced acute renal failure in mice. Effects of indomethacin and the thromboxane-synthetase antagonist UK 38.485.

Functional acute renal failure (ARF) was induced within 24 h following i.p. injection of 200 micrograms E. coli endotoxins (ET) into C3H/HeHan mice. Pre- and post-treatment with either UK 38.485, a selective thromboxane (TX)-synthetase inhibitor, or with the cyclo-oxigenase inhibitor, indomethacin (IM), does not prevent acute renal failure in these mice. Histologically, only very little fibrin degradation and few microthrombi are present 24 h later in the kidneys, so that disseminated intravascular coagulation (DIC) mechanisms cannot have caused the significant azotemia. Slight histological changes are accentuated in the UK 38.485-treated group. Only the indomethacin group has a significantly increased mortality as compared to all other groups. We conclude from our study that with low dosages of endotoxins functional ARF can be induced in mice without a circulatory shock and early mortality and that both UK 38.485 and IM are of little value in preventing it.

Acute Kidney Injury↗

Organ distribution of aluminium in uremic rats: influence of parathyroid hormone and 1,25-dihydroxyvitamin D3.

Investigations were performed in order to see whether or not the application of parathyroid hormone or 1,25-dihydroxyvitamin D3, or both might influence the organ distribution of orally and parentally administered aluminium in control and uremic rats. The data show that 1,25-dihydroxyvitamin D3, affects the organ uptake in a different way than parathyroid hormone. Whereas parathyroid hormone increased the aluminium concentration in the liver, 1,25-dihydroxyvitamin D3 enhanced the aluminium uptake in the heart and the muscle, on the other hand, simultaneous application of 1,25-dihydroxyvitamin D3 and parathyroid hormone decreased the aluminium content of the bone, liver and brain.

Aluminum↗