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K Ostrowski

Publications and source records attributed to K Ostrowski.

At least 73 records · Page 4Linked to original sources
PubMed1994

Bone powder exposed to the action of 12C and 25Mg ion beams as investigated by electron paramagnetic resonance spectroscopy.

Bovine compact bone powder was irradiated with alpha-particles of 241Am, 12C6+ and 35Mg12+ ion beams, then examined by the e.p.r. spectroscopy. The stable e.p.r. signal found is of the same characteristic as that observed in gamma-irradiated bone (g perpendicular = 2.0017, g parallel = 1.9973, delta Hpp = 0.85 mT). Thus, the structure of radiation induced paramagnetic center in bone does not depend on the LET of radiation used. The radiolytic yields of the formation of stable paramagnetic centres in bone powder irradiated with gamma-rays are G gamma = 0.08 +/- 0.01 while with 12C6+ ion beams roughly about Gc = 0.02, respectively.

Animals↗
PubMed1994

In situ perfusion and UW solution used for storage did not decrease the incidence of ATN in kidneys harvested from hemodynamically unstable donors.

The incidence of acute tubular necrosis ATN after cadaveric kidney transplantation in our centre has been in the range of 50%. A prospective study was carried out in 1991 and 1992 to assess the effect of in situ perfusion and hypothermic storage of kidneys harvested from brain-dead haemodynamically stable and unstable donors. Three litres of Ringer's solution were used for in situ perfusion. In 40 cases, the kidneys were stored in Euro-Collins (EC) solution and in the other 78 cases, in University of Wisconsin (UW) solution. Among the factors that could contribute to ATN, we analysed warm ischaemia time, anastomosis time and cold storage time. Function was considered to be delayed if the patient required posttransplantation dialysis. The donors were considered haemodynamically unstable when hypotension before harvesting was present (BP < 70 mm Hg over 2 h) despite high doses (> 15 microg/kg per minute) of dopamine or when cardiac arrest occurred at the time of harvesting and oliguria had been present for at least 2 h. Haemodynamically stable donors with a BP greater than 80 mm Hg had a normal diuresis. In all donors in this group the dose of dopamine was lower than 10 microg/kg per minute. The study showed that storage in UW solution did not influence the incidence of ATN in kidneys harvested from haemodynamically unstable donors. Differences observed in our study were due to haemodynamic status preceding donor nephrectomy and length of cold storage time.

Adenosine↗
PubMed1994

[Evaluation of bone mineralization in patients on maintenance hemodialysis].

Bone loss and bone formation and mineralization abnormalities resulting from disturbances in calcium and phosphorus metabolism are frequent in chronic renal failure. Haemodialysis permits long-term survival of patients with end-stage renal disease. This is the reason, why renal osteodystrophy became an important diagnostic and therapeutical problem. Very low occurrence of fractures among haemodialysed patients in our clinic, stimulated our efforts to elucidate the causes of this phenomenon. The aim of this study was to compare bone mineral densities in haemodialysed patients and healthy volunteers. 47 patients on maintenance haemodialysis (16 F, 31 M) and 55 healthy volunteers (33 F, 22 M) with normal renal function were investigated. Endocrinopathy or any other diseases that could cause changes in bone metabolism were excluded. Age distribution in both groups was similar. Patients maintained on low sodium and phosphorus diet additionally were supplemented with large doses of calcium carbonate. Haemodialyses were performed using reverse-osmosis water. BMD (Bone Mineral Density) was measured using QCT (Quantitative Computed Tomography) and was expressed as an average hydroxyapatite content in lumbar vertebraes L1-L4. The obtained results indicate high BMD of vertebral bones in haemodialysed patients from our Dialysis Department. BMD was similar to that observed in healthy volunteers. This could at least partially explain low occurrence (2 in 142 pts-years) of fractures in ou uraemic patients. However we were unable to point exactly the simple factor responsible for this positive phenomenon. We hope that introduction of our haemodialysis scheme can help patients to avoid renal osteodystrophy.

Adult↗
PubMed1993

Efficiency of hemodialysis of pyrimidine compounds in patients with chronic renal failure.

The accumulation in blood plasma and efficiency of hemodialysis of pyrimidine compounds (orotic acid, orotidine, pseudouridine, uridine, thymine) as well as uric acid and creatinine in 23 patients with chronic renal failure (CRF) was investigated. As a reference, the analysis of the above metabolites in the plasma of 30 healthy volunteers was performed. Among examined compounds, pseudouridine possessed the highest capability of accumulation in blood plasma (25 times higher concentration than physiological). It coincided with the lowest efficiency of pseudouridine hemodialysis (44%) and the longest T1/2 (relative to creatinine) in plasma. A significant linear correlation (r = 0.81, p < 0.001) between efficiency of creatinine and pseudouridine hemodialysis was calculated. The concentration of orotic acid in the blood plasma of patients before hemodialysis exceeded 14 times its level in healthy subjects; the inhibition of uric acid synthesis by allopurinol in dialyzed patients was accompanied by enlargement of orotidine and orotate accumulation in blood plasma. Extremely high plasma concentration of examined pyrimidines remaining elevated after hemodialysis creates an additional hazard for tissue metabolism and health of patients with CRF.

Adult↗
PubMed1993

[Renal biopsy in the aged].

Pathological findings in urinalysis in the aged persons are usually thought to be caused by pathologic processes other than glomerulopathy. Histological evaluation of renal tissue in older patients is extremely difficult due to coexistence of involuntary changes-hyalinosis, increase in mesangial matrix content, and vascular changes. The aim of the study was to evaluate frequency of glomerulonephritis, both primary and secondary in persons older than 60. In this group, as compared to the younger people the secondary glomerulonephritis was more frequent, amyloidosis and vasculitis nodosa being the most frequent. In primary glomerulonephritis mesangiocapillary type dominate, quite often some tendency to hyalinization could be observed. Renal biopsy is useful as a diagnostic tool in both the aged and young. It should be performed regardless the patients age.

Adult↗
PubMed1993

[Pulsed dose intravenous steroid treatment in the therapy of acute lupus nephritis with renal failure].

The effectiveness of pulse-dose intravenous steroid treatment was studied in acute phase of lupus nephritis with renal failure rapidly progressive despite conventional therapy. On 5-6 consecutive days 1g of prednisolone or methylprednisolone was given intravenously to 33 patients with a mean initial serum creatinine 5.9 +/- 4.1 mg/dl (521.6 +/- 362.4 mumol/l); then the patients were placed on conventional therapy. Immediate remission (group I), lasting at least 6 months, was achieved in 23 patients (69.7%), with a significant decrease of serum creatinine from 4.5 +/- 3.2 mg/dl (397.8 +/- 282.9 mumol/l) to 1.3 +/- 0.7 mg/dl (114.9 +/- 61.9 mumol/l) (p < 0.001) within 3 months. In 19 patients the remission lasted more than a year; till now the longest one is 13 years. In 10 patients (group II), the therapy brought no improvement and they went quickly into terminal renal failure. In this group the initial serum creatinine was 8.9 +/- 3.6 mg/dl (786.8 +/- 318.2 mumol/l), which was much higher than in the I group. All those patients were admitted to chronic dialysis programme; however, 5 of them died during the first 3 months of the treatment. The most frequent complications of the therapy were infections; all but one (a generalized zoster being a cause of death) caused no therapeutic difficulties. Pulse-dose intravenous steroid treatment makes achieving rapid clinical remission possible even in cases of advanced renal failure due to acute phase of lupus nephritis, refractory to conventional therapy.

Adolescent↗
PubMed1993

[Test with calcitonin as an index of parathyroid function in chronic renal failure].

The aim of this study was to evaluate the clinical usefulness of the calcitonin test in predicting the hyperparathyroid bone disease severity in uremia. 200 IU of synthetic salmon calcitonin was given intranasally to 77 hemodialysed patients with end-stage renal failure. Before the test, serum calcium, PTH and serum alkaline phosphatase had been sampled; serum calcium was determined also in 2 to 4 hours after. The subjects were divided into 3 groups according to their serum PTH levels. Group I consisted of 24 patients with at least 10-fold serum PTH elevation, group II of 34 patients with intermediate values, and group III of 19 patients with serum PTH within normal range. In the group I the mean serum calcium fall was 0.32 +/- 0.16 mmol/l (1.28 +/- 0.64 mg/dl) (p < 0.001) and 0.27 +/- 0.15 mmol/l (1.08 +/- 0.60 mg/dl) (p < 0.001), after 2 to 4 hours respectively. In the group II serum calcium decreased by 0.16 +/- 0.12 mmol/l (0.64 +/- 0.48 mg/dl) after 2 hours and by 0.14 +/- 0.09 mmol/l (0.56 +/- 0.36 mg/dl) after 4 hours; the differences were statistically insignificant. In the group III no reduction in serum calcium was observed. In the whole 77 patients population significant linear correlations between the hypocalcemic response and iPTH as well as serum alkaline phosphatase were found. Our results confirm that the calcitonin-induced hypocalcemia a test can be, in addition to serum alkaline phosphatase and PTH evaluation, a simple and useful index of advanced hyperparathyroid bone disease in hemodialysed patients with chronic renal failure.

Adult↗
PubMed1993

[Oral pulsatile therapy with active vitamin D3 metabolites--an efficient method of parathyroid hormone synthesis suppression in uremic patients with severe hyperparathyroidism. A pilot study].

Standard therapy with orally administered active metabolites of vitamin D3 often does not satisfactorily control the biochemical manifestations of secondary hyperparathyroidism in uremic patients. This may be due to inadequate serum concentrations of 1,25 (OH)2D3 achieved during the treatment. Eighteen patients on chronic hemodialysis (HD) with severe hyperparathyroidism were given high doses of calcitriol (1,25 (OH)2D3) or alphacalcidol (1 alpha-OH-D3) orally, in ten evenings preceding each HD session. The effect of the treatment on circulating parathyroid hormone (PTH), serum hydroxyproline, serum alkaline phosphatase and bone isoenzyme was examined in a pilot study during 5 weeks. Irrespective the preparation given the treatment caused 71.7 +/- 22.2% reduction of intact serum PTH concentration with only moderate rise of serum calcium. A decrease of serum hydroxyproline and activity of alkaline phosphatase with its bone fraction, the direct indexes of bone turnover reduction, was also observed. With ongoing calcium carbonate therapy (3-6 g/day) 5 episodes of mild, asymptomatic hypercalcemia was observed for the 108 times of the total number of examinations; in those cases the dose of alphacalcidol was reduced. Our observations indicate that intermittent administration of 1,25 (OH)2D3 as well as 1 alpha-OH-D3 in high oral doses effectively suppress PTH synthesis in uremic hyperparathyroidism already in a couple of weeks. The effect is similar to that obtained with intravenous administration of the vitamin D3 active metabolites.

Administration, Oral↗
PubMed1991

Radiation-induced paramagnetic centers in research on bone physiopathology.

It has been found that ionizing radiation induces stable paramagnetic centers in the crystalline lattice of bone hydroxyapatite (HA). These defects, which can be detected and measured by electron spin resonance (ESR) spectrometry, can be treated as a new kind of biologic marker and used for the following: (1) evaluation of crystallinity of bone mineral, because the yield of these centers depends on the size of HA crystals; (2) quantification of the rebuilding process of radiation-sterilized bone grafts, because of the stability of the centers; and (3) estimation of the dose of ionizing radiation absorbed by living organisms, because of the linear relation between the dose of ionizing radiation and the yield of radiation-induced paramagnetic centers in bone mineral.

Animals↗
PubMed1991

Effect of radiation sterilization on the osteoinductive properties and the rate of remodeling of bone implants preserved by lyophilization and deep-freezing.

The effect of various doses of ionizing radiation on the osteoinductive properties of decalcified bone matrices implanted heterotopically and on the rate of remodeling of nondecalcified bone grafts implanted orthotopically in allogeneic systems was studied. Decalcified bone matrices and nondecalcified bone grafts were preserved by lyophilization or by deep-freezing and were subsequently irradiated with appropriate doses at room temperature or at -72 degrees. Lyophilized matrices irradiated at room temperature with 35 and 50 kGy, respectively, were completely resorbed five weeks after heterotopic implantation into the muscles and did not induce osteogenesis, whereas the resorption of deep-frozen ones irradiated with the same doses at -72 degrees was slower and new bone formation was induced. The preservation of the osteoinductive capacity of irradiated, deep-frozen matrices may depend on two factors: reduction of radiation damage on the inducing agents and collagen irradiated in the presence of water, which may diminish the rate of matrix resorption. The rate of remodeling of undecalcified deep-frozen bone implants irradiated at -72 degrees and grafted orthotopically was higher than that of lyophilized ones irradiated at room temperature. It is possible that the temperature during irradiation plays a critical role in protection against radiation damage.

Animals↗
PubMed1988

Differences in the kinetics of the mineralization process in endochondral and intramembranous osteogenesis in human fetal development.

About 300 samples of bone tissue from femoral diaphyses and from parietal bones of calvaria were collected from human fetuses aged from 6-8 to 40-41 weeks in order to compare the kinetics of the mineralization process in endochondral and intramembranous bone formation. The crystallinity of bone mineral was evaluated by the method based on electron spin resonance (ESR) spectrometry, and mineral content was measured after ashing of the samples. Highly significant differences in the kinetics of deposition of mineral (ash content) and maturation of deposited mineral (crystallinity coefficient) were found between parietal bones and femoral diaphyses in the course of fetal development. In the early stages of development (6-8 to 10-12 weeks), the content of mineral and its crystallinity in parietal bones were significantly lower than in femoral diaphyses. In the parietal bones a gradual increase in both values was observed until they reached a plateau at the age of 30 weeks. On the other hand, in femoral diaphyses of 6-8-week-old fetuses mineral content was high and deposited mineral showed a high degree of crystallinity. Both these values did not change significantly until birth. The differences in kinetics of the mineralization process between the weight-bearing bones and bones that are not exposed to the influence of strong external forces are most probably genetically conditioned. The collected data supply embryological information and might be used in the future for evaluation of pathologic changes in skeletal development.

Embryonic and Fetal Development↗
PubMed1988

Effect of 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) and dichloromethylidene-bisphosphonate (Cl2MBP) on the structure of the organic matrix of heterotopically induced bone tissue.

The effect of 1-hydroxyethylidene-1,1-bisphosphonate (HEBP) and dichloromethylidene-bisphosphonate (Cl2MBP) on the structure of the organic matrix of heterotopically induced bone in guinea pig was studied. Heterotopic bone formation was induced by transplantation of allogenic urinary bladder epithelium. Starting from the day of transplantation the animals were treated subcutaneously with HEBP and Cl2MBP with a dose of 12.5 mg P/kg/day during 35 days. The control group was injected with 0.9% NaCl solution. The advantage of heterotopic bone induction as an experimental model is the fact that the applied drugs act on de novo bone formation. Collagen fibers were treated as markers of bone because their size and spatial arrangement reflect the structure and maturity of organic matrix of this tissue. Decalcified histological sections of induced bone, taken 35 days after implantation of inductor, were stained by the picrosirius method. This staining enhances the natural birefringency of collagen fibers and allows for better and specific visualization of collagen fibers bundles under polarizing microscope. In this way the amount of information in the analysed image is increased. Thirty five microphotographs were analysed from each of the investigated groups with the use of optical diffractometry. The radial distribution of light intensity in diffraction patterns was analysed what allowed to evaluate spatial frequencies connected with the width of collagen bundles in induced bone tissue. Since the spatial arrangement of collagen fibers in newly formed bone is random, analysis of angular distribution of light intensity in diffractograms was not performed. Using discriminant analysis the significant differences between all three studied groups of animals were found.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1986

Numerical evaluation of changes in the cytoplasmic microtubule complex of C3H mouse cells by optical diffractometry and of changes in cell shape by Fourier analysis.

MO mouse cells in culture on glass were treated with taxol, or nocodazole, or incubated at 4 degrees C to alter their cytoplasmic microtubule complex (CMTC). From each treated group and from an untreated group, 30 cells stained with an antiserum against tubulin, were photographed under the photomicroscope, and negatives were analysed by optical diffractometry. Differences between groups of cells were tested by variance analysis. Phase-contrast micrographs of the same cells were used for Fourier analysis of cell shape. Both types of analyses provided numerical objective data about changes in the CMTC and in cell shape that were typical for the kind of treatment. We conclude that optical diffractometry of immunostained cells and Fourier analysis of cell shape are complementary to photomicroscopy for the study of the CMTC in cell populations cultured on an artificial substrate.

Alkaloids↗