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Biomedical subjects

J Kovarik

Publications and source records attributed to J Kovarik.

At least 145 records · Page 8Linked to original sources
PubMed1986

[Sonographically demonstrable changes following percutaneous kidney biopsy].

For diagnosis and therapeutic strategies exact histological diagnosis of certain renal diseases is of great importance. Biopsy, therefore, is an integrated component of patient management. Haemorrhage is the most common complication following percutaneous renal biopsy. Gross haematuria can easily be detected, whereas perirenal bleeding is harder to detect. A high incidence of perirenal haematomas after biopsy can be evaluated with the help of sonography. In a survey of 207 percutaneous renal biopsies performed in 168 patients, we found 64 perirenal haematomas (30.9%). 2 haematomas (0.96%) required surgical intervention. In 4 patients (1.9%) transitory gross haematuria with obstruction of the bladder by blood clots occurred. These were removed by cystoscopy.

Adolescent↗
PubMed1986

Relationship of interferon-gamma and neopterin levels during stimulation with alloantigens in vivo and in vitro.

We have recently shown that interferon-gamma is capable of activating the key enzyme of pterin biosynthesis in macrophages. This leads to excretion of the stable degradation product neopterin. In this article we present experimental evidence suggesting that stimulation of T cells by alloantigens is associated with release of interferon-gamma--which, in the case of rejection, is locally restricted and not always detectable in the bloodstream. Neopterin induced by this lymphokine, however, readily penetrates tissue barriers and is detectable in the serum. This conclusion is based on two different sets of observations: (1) If supernatants of MLCs are compared with sera from patients with documented acute rejection episodes for their interferon-gamma and neopterin levels, a marked gradient is observed to exist between interferon levels measured in vitro and in vivo; this is not the case for neopterin for which comparable levels were seen. (2) Detection of interferon-gamma in sera of allograft recipients invariably precedes an increase of neopterin; on the other hand, increasing neopterin counts are also seen in the absence of detectable interferon-gamma levels in the serum. It thus appears that although interferon-gamma release during allograft rejection is primarily restricted to the tissue, evaluation of certain metabolites of interferon-dependent metabolic pathways enables definition of its endogenous release. Whereas interferon gamma represents a less reliable marker in the monitoring of rejection episodes, it might offer an additional means to differentiate rejection from systemic infections. Such a discrimination can not be achieved with the neopterin marker.

Acute Disease↗
PubMed1986

Center-specific variations of thyroid hormone serum levels in hemodialysis patients.

Thyroid hormone (free and total thyroxine, total 3,5,3'- and 3,3'5'-triiodothyronine, thyroxine-binding globulin, thyrotropin) serum concentrations were measured in 107 uremic patients of 4 hemodialysis centers, in order to study the prevalence of hypothyroidism in hemodialysis patients. In accordance with the clinical impression there was no laboratory evidence of thyroid dysfunction. In spite of the fact that all patients had the expected low-T3 syndrome, there were highly significant differences between the mean thyroid hormone concentrations of the 4 different centers. The center with the highest thyroid hormone levels (all normal except for borderline low 3,5,3'-triiodothyronine) also had the lowest urea levels, indicating the relatively best metabolic control. One center had significantly lower hormone levels than the other 3 centers (all hormones except free thyroxine were below normal) with urea levels that did not differ significantly from one of these centers. A retrospective analysis of patients and of the techniques of dialysis of 3 centers excluded factors like heparin or the length of time on dialysis to be the reason for the low values of this center. Finally, only the significantly higher proportion of unsuccessfully transplanted patients and some technical differences (lack of water treatment, regenerated cellulose as dialyser membrane, and low magnesium content in the dialysate) unique for this center remained as possible factors that may speculatively explain the observed low thyroid hormone values.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1986

Determination of circulating monomeric katacalcin and calcitonin: physiological studies in normal subjects.

Katacalcin is a recently discovered peptide, contained within the calcitonin precursor. For the highly sensitive radioimmunological measurement of katacalcin and calcitonin we used extraction on C-18, thereby lowering the detection limits in serum to 0.8 pmol/l (katacalcin) and 0.7 pmol/l (calcitonin), and simultaneously improving the specificities of both assays for the monomeric forms of the peptides. Extraction recoveries were greater than 96% and greater than 95% for pure monoiodinated [125I]Tyr(0)-katacalcin and [125I]calcitonin, respectively; and 95-98% and 91-97% respectively for the corresponding unlabelled peptides. This method is sufficiently sensitive and specific for studies on the physiology of both peptides. Gel filtration of serum from a patient with medullary carcinoma of the thyroid showed that the majority of high molecular weight forms of katacalcin and calcitonin did not bind to C-18, and that the eluted material consisted to more than 90% of monomeric katacalcin and calcitonin. Basal levels (mean +/- SEM) of katacalcin were higher in men (3.0 +/- 0.6 pmol/l, age less than 40 years, and 1.8 +/- 0.4 pmol/l, age greater than 40 years) and younger women (2.1 +/- 0.4 pmol/l) than in older women (1.3 +/- 0.6 pmol/l; p less than 0.02). The respective values for calcitonin were 5.1 +/- 0.9 and 4.0 +/- 0.6 pmol/l for young and older men, and 2.3 +/- 0.4 and 2.8 +/- 0.8 pmol/l for young and older women, with a significant sex-related difference in both age groups. Basal serum levels of katacalcin and calcitonin were highly correlated (katacalcin = 0.66 calcitonin -0.12 pmol/l; p less than 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1986

A new algorithm for individual dialysis prescription based on urea kinetics.

Methods for calculating required dialysis time to maintain certain blood urea nitrogen levels predialytically thus far have neglected the influence of ultrafiltration during hemodialysis and of weight changes in the interdialytic period. We therefore have developed a new algorithm for individual dialysis prescription based on urea kinetics which further optimizes accuracy of dialysis prescription by considering these two factors. The accuracy of this new method was proven in a prospective follow-up of 3 patients during some 9 consecutive hemodialysis session. It was found that there was a very close relation between the measured and the predicted values of blood urea nitrogen, the difference being only due to variations in dietary protein intake as the patients were kept on liberal food intake. The new algorithm is easily implemented into a pocket calculator and thus can be used under arbitrary dialysis conditions.

Algorithms↗
PubMed1985

[Individual dialysis using computer-controlled prescription].

The use of urea kinetics as basis for optimization and individualization of renal replacement therapy has become quite popular over the last decade. The rationale underlying the use of blood urea nitrogen for monitoring or targeting dialysis therapy is based on the report of an American multicentre cooperative dialysis study showing that blood urea nitrogen concentrations are closely correlated to the occurrence of morbidity and complications in dialysis patients. In order to further optimize the accuracy of dialysis prescription we have developed a new algorithm for estimation of the dialysis time needed to reach a certain blood urea nitrogen concentration, which--in contrast to all methods employed so far--enables accurate calculation of ultrafiltration during haemodialysis and of weight changes in the interdialytic period.

Blood Urea Nitrogen↗
PubMed1985

[EHDP (ethylidene-1-hydroxy-1,1-diphosphonate) in the treatment of polyosseous Paget disease].

13 patients with polyosseous Paget's disease were treated for a mean period of 7 months with disodium etidronate (EHDP, ethylidene-1-hydroxy-1,1-diphosphonate); the average daily dosage was 5 mg/kg body weight. Subjectively, all patients reported a considerable improvement, in particular with regard to pain. Objectively, a significant decrease in plasma alkaline phosphatase activity and in urinary hydroxyproline excretion was observed. Bone scintigraphy showed a decreased activity of bone lesions after therapy, but no clear-cut regression was found radiologically. No serious side-effects were observed during treatment with EHDP and oral administration of the drug proved to be advantageous.

Aged↗
PubMed1985

Skin tests with autologous cholesteryl hemisuccinate treated tumour cells in cancer patients.

Skin tests with autologous irradiated tumour cells were performed in 20 malignant melanoma, 7 breast and 6 ovarian cancer patients. In the majority of cases evident reaction was noted with cholesteryl hemisuccinate (CHS)-treated cells while the reaction with untreated cells was mostly negative. No correlation was found between this reactivity and the ability of patients to be sensitized to DNCB and to their reactivity to PPD. No correlation was found between reactivity to CHS-treated tumour cells and the stage and course of the disease.

Breast Neoplasms↗
PubMed1985

Glucose metabolism and insulin sensitivity in patients on chronic hemodialysis.

In order to evaluate the potential role of parathyroid hormone on glucose metabolism in patients on chronic hemodialysis hyperglycemic clamp studies were performed in 7 parathyroidectomized and 11 nonparathyroidectomized patients on chronic hemodialysis and in healthy controls. There were no significant differences in the peripheral glucose uptake of the 3 groups. The beta cell response to hyperglycemia during the early phase as well as during the steady state was almost identical in controls and in nonparathyroidectomized uremics, whereas in the parathyroidectomized group a markedly enhanced insulin secretion was found. Calculated tissue sensitivity to insulin therefore was equal in controls and in nonparathyroidectomized uremics, whereas patients after parathyroidectomy had peripheral insulin resistance. Our results demonstrate that patients on chronic hemodialysis apparently have normal peripheral glucose uptake. The subgroup of patients who have undergone parathyroidectomy, however, show an enhanced insulin response to hyperglycemia suggesting peripheral insulin resistance. We conclude that longstanding and severe secondary hyperparathyroidism--the usual cause for parathyroidectomy in these patients--results in irreversible insulin resistance with a compensatory increase of insulin secretion.

Adult↗
PubMed1985

Iron removal by desferrioxamine in patients on chronic hemodialysis--kinetic study and long-term results.

Serum ferritin levels, cumulative number of administered blood transfusions, number of monthly transfused blood units and total months on hemodialysis (HD) treatment differed significantly in 7 patients on hemodialysis with clinical, biochemical and histological evidence of hemosiderosis, when compared to 37 controls (p less than 0.001 for all parameters). As a new treatment method desferrioxamine (DFO) therapy was introduced for iron detoxification in these hemosiderotic chronically hemodialyzed patients. Hence, to maximize the biological half-time, 30 mg/kg body weight DFO were given after the end of HD in the iron-loaded patients. Iron removal during the subsequent HD and the increase of iron excretion by the stool after DFO was measured by atomic absorption spectroscopy. Iron removal by the artificial kidney was calculated by investigating the function (QDi + QF)CDo over the duration of HD treatment, which equals the total amount of iron removal during HD. Using numerical integration of measured data this removal was found to be 21.8 +/- 6.9 mg whereas cumulative iron loss via the feces was found to be 36.5 +/- 14.6 mg. Therefore, total iron elimination was calculated to be on average 50-60 mg after administration of a single dose of DFO. Furthermore, long-term treatment of 5 patients resulted in a significant decrease of serum ferritin levels from 2,309 +/- 295 to 715 +/- 177 ng WHO/ml (p less than 0.001) after a period of 36 +/- 5 months. We conclude, that DFO in a dosage of 30 mg/kg body weight given at the end of HD is able to remove more than 500 mg iron/month if it is administered following each HD. Long-term results indicate negative iron balance without significant change of transfusion frequency if not more than 2 U of blood (500 mg iron) are administered within 1 month. This treatment schedule might be superior compared to the previously used methods of administration where DFO was given at the beginning or throughout HD.

Adolescent↗
PubMed1985

[Diastolic compression of the right atrium and right ventricle as an echocardiographic sign of pericardial tamponade. Case report].

A 33 years old female patient requiring regular hemodialysis for chronic renal failure exhibited a severe hypotensive episode. 2-dimensional echocardiography enabled rapid recognition of the underlying cause. 2-dimensional echocardiography revealed a large pericardial effusion and from the apical window a marked diastolic compression of the right atrium and the right ventricle was noted. These findings have been previously described to be specific for cardiac tamponade. After removal of 400 ml of fluid by pericardiocentesis the clinical symptoms rapidly improved and in the 2-dimensional echocardiography diastolic compression of the right sided heart chambers was not longer evident, although a substantial amount of pericardial fluid was still present. This case report underlines the clinical usefulness of 2-dimensional echocardiography for the diagnosis of cardiac tamponade.

Adult↗
PubMed1984

Parathyroid hormone does not inhibit platelet aggregation.

The suggestion that parathyroid hormone (PTH) is a major uraemic toxin was examined by testing the effects of synthetic human PTH fragments and synthetic bovine PTH on ADP-induced and collagen-induced platelet aggregation. Whereas the bovine parathyroid-gland extracts inhibited platelet aggregation in a dose-dependent manner, none of the synthetic compounds was effective even at high concentrations. It is suggested that the inhibition of platelet aggregation by extracts of bovine parathyroid glands is not caused by PTH fragments and is probably an effect of other constituents contained in the extract. These findings argue against a role of PTH in the pathogenesis of platelet dysfunction and bleeding tendency in uraemia and were supported by platelet-aggregation studies in 6 patients with primary hyperparathyroidism. Platelet aggregation was normal before and unchanged after surgery of the parathyroid glands.

Adenosine Diphosphate↗
PubMed1984

Primary hyperparathyroidism is associated with decreased insulin receptor binding and glucose intolerance.

We studied insulin receptor-binding and carbohydrate and metabolism in 15 patients with symptomatic primary hyperparathyroidism in comparison with 20 healthy controls. Insulin binding to monocytes and erythrocytes was measured by radioreceptor-ligand-assay. Furthermore, patients and controls were characterized by testing oral (100 g glucose load) glucose tolerance as well as insulin tolerance (0.1U insulin/kg body weight). Compared with controls, patients with primary hyperparathyroidism exhibited marked hyperinsulinemia (P less than 0.01) and significantly higher glucose levels (P less than 0.01) after an oral glucose load. The glucose lowering effect of intravenous insulin was significantly diminished in primary hyperparathyroidism compared with controls (P less than 0.01). Receptor studies revealed a significantly lower (P less than 0.01) insulin binding to monocytes and to erythrocytes in patients with primary hyperparathyroidism compared with controls. The present data indicate an insulin-resistant state in primary hyperparathyroidism, which is caused at least in part, by a downregulation of insulin receptors.

Adult↗