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Biomedical subjects

M Radovic

Publications and source records attributed to M Radovic.

7 recordsLinked to original sources
PubMed2006

Fuzzy role of hyperhomocysteinemia in hemodialysis patients' mortality.

Recent studies give contradictory data regarding the role of hyperhomocysteinemia (hyperHcy) in cardiovascular (CV) morbidity and mortality in hemodialysis (HD) patients. The aims of the present study were to detect the most powerful variables associated with hyperHcy as well as to evaluate the relationship between hyperHcy and CV morbidity and mortality. The prospective follow-up study of 113 patients (52 males, aged 55.2+/-13.1 years) maintained by HD for 81.9+/-56.9 months at our Institute was carried out over 55 months. Fifty-seven (50.4%) of the examined patients were supplemented with water-soluble vitamins including folic acid and vitamin B complex pills or ampoules. Total serum Hcy level was determined by high-performance liquid chromatography, while serum folic acid and vitamin B(12) were measured by radioimmunoassay. The multivariate analysis showed HD duration (r=0.608; P=0.02) and folic acid serum level (r=-0.580; P=0.03) to be significant predictors of serum tHcy concentration. The multivariate Cox regression analysis of CV mortality revealed diabetes mellitus and heart failure as the most powerful positive predictors, while creatinine, albumin and vitamins intake therapy were negative predictors of CV mortality. Long-term supplementation with the usual doses of vitamins is followed with increased survival in hemodialysis patients. Although total serum Hcy level was not found to be a predictor of overall and CV mortality, the role of hyperHcy. as risk factor for CVD cannot be excluded in hemodialysis patients.

Adult↗
PubMed2005

Dynamic elastic hysteretic solids and dislocations.

Recently we showed that the quasistatic response of nonlinear mesoscopic elastic solids to stress can be explained by invoking the formation of dislocation-based incipient kink bands. In this Letter, using resonant ultrasound spectroscopy, we confirm that the dynamical behavior of these nonlinear elastic systems is due to the interaction of dislocations with the ultrasound waves, thus resolving a long-standing mystery.

Journal Article↗
PubMed2005

Comparative survival analysis of urea kinetic based indices.

BACKGROUND: Although urea kinetic modeling indices for measuring dialysis dose are recommended by world expert groups, it is not quite clear whether some of these are superior in predicting the outcome over others. This prospective, single-center study was carried out with the aim to compare predictive value of different indices and methods of measuring dialysis dose. METHODS: The analysis included 93 anuric patients having been on hemodialysis for at least 2 years who were followed-up for 75-months. The dialysis dose was measured by Kt/V (formal UKM, 3 and 2 urea samples), Kt/V (Daugirdas), Kt/V (Lowrie), eKt/V (Daugirdas), URR and TAC urea. RESULTS: Correlations between dialysis indices and survival time were significant for all indices (p<0.01) except for TAC. All indices, except for TAC urea, were significant predictors of mortality (multivariate Cox regression analysis; p<0.01) and differences of significant levels among these colinear parameters were small. CONCLUSION: All examined indices except for TAC urea were highly predictive of patient mortality. Daugirdas and Lowrie simplified Kt/V indices are as predictive of all-cause mortality as more complex formal UKM methods in long-term patients on a 3x4h/week schedule.

Adult↗
PubMed2003

Fully reversible, dislocation-based compressive deformation of Ti3SiC2 to 1 GPa.

Dislocation-based deformation in crystalline solids is almost always plastic. Here we show that polycrystalline samples of Ti3SiC2 loaded cyclically at room temperature, in compression, to stresses up to 1 GPa, fully recover on the removal of the load, while dissipating about 25% (0.7 MJ x m(-3)) of the mechanical energy. The stress-strain curves outline fully reversible, rate-independent, closed hysteresis loops that are strongly influenced by grain size, with the energy dissipated being significantly larger in the coarse-grained material. At temperatures greater than 1,000 degrees C, the loops are open, the response is strain-rate dependent, and cyclic hardening is observed. This hitherto unreported phenomenon is attributed to the reversible formation and annihilation of incipient kink bands at room-temperature deformation. At higher temperatures, the incipient kink bands dissociate and coalesce to form regular irreversible kink bands. The loss factor for Ti3SiC2 is higher than most woods, and comparable to polypropylene and nylon. The technological implications of having a stiff, lightweight machinable ceramic that can dissipate up to 25% of the mechanical energy per cycle are discussed.

Carbon↗
PubMed1999

Serum erythropoietin and interleukin-6 levels in hemodialysis patients with hepatitis virus infection.

The influence of hepatitis B (HBV) and hepatitis C virus (HCV) infection on blood hemoglobin (Hb) and serum erythropoietin (Epo) and interleukin-6 (IL-6) concentrations was studied in 48 anemic patients on regular hemodialysis. They were grouped as follows: (I) 19 patients whose Hb values improved after infection (Hb > 85 g/L), (II) 10 patients with persisting anemia after infection (Hb < 75 g/L), and, without hepatitis virus markers (III) 8 patients with Hb > 85 g/L and (IV) 11 patients with Hb < 75 g/L. Serum immunoreactive Epo levels were significantly higher in group I (34.4+/-47.1 U/L) than in the other groups (II, 10.8+/-6.0; III, 7.9+/-3.2; IV, 8.4+/-4.3). Serum IL-6 was higher in group I than group III (7.7+/-7.8 pg/ml vs. 3.6+/-2.4; p = 0.05) but similar to the other groups. Hb levels in group I were maximal at the time of serum alanine aminotransferase normalization. Red cell production increases as a result of elevated circulating Epo during hepatic regeneration after HBV or HCV infection.

Anemia↗
PubMed1991

Therapeutic leukapheresis.

For the majority of leukemic patients, leukapheresis represents emergency treatment aimed at reducing the number of white blood cells and producing an immediate improvement in the clinical picture. We have shown that leukapheresis procedures performed for the therapy of leukocytosis in 4 patients with acute leukemia (2 myelocytic; 1 lymphocytic; 1 monoblastic) resulted in marked reduction in the white blood cell count and a considerable reduction in symptomatology. Repeat removal of white blood cells applied in 20 instances for patients with chronic myelocytic leukemia also produced a significant decrease in the cell count and relief of symptoms such as sweating, malaise, and pain due to splenomegaly. In chronic lymphocytic leukemia (31 patients), intensive and frequent leukapheresis procedures were followed by a marked fall in white blood cell count, regression of splenomegaly/lymphadenopathy and resolution of many symptoms and signs induced by the large number of cells.

Adolescent↗