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Biomedical subjects

I Popov

Publications and source records attributed to I Popov.

At least 199 records · Page 11Linked to original sources
PubMedDate not supplied

Photochemiluminescent detection of antiradical activity. VI. Antioxidant characteristics of human blood plasma, low density lipoprotein, serum albumin and amino acids during in vitro oxidation.

During investigation of the mechanism of therapeutic efficacy of UV (254 nm)-irradiated autologous blood, the antioxidant capacity (AC) of plasma, serum albumin, 20 amino acids, uric acid, ascorbic acid and alpha-tocopherol was measured after irradiation in vitro. AC of plasma demonstrated a biphasic time course (decrease to in a minimum (greater zero) followed by an increase). AC of uric acid, ascorbic acid and alpha-tocopherol diminished under irradiation to zero. In contrast, albumin and seven amino acids developed AC following irradiation. During the Cu(+2)-induced oxidation of low-density lipoprotein (LDL), the AC measured in a system for water-soluble substances appeared, after a lag-phase, to be comparable to that of the conjugated diene formation; AC of LDL measured in a system for lipid-soluble substances demonstrated a biphasic course. Our results suggest that: (a) the oxidized products of some amino acids and proteins acquire antiradical properties at the same time that they are being produced; (b) the biphasic character of changes of antioxidant properties of blood plasma during UV irradiation represents the overlapping of two processes: disappearing of antioxidants and acquisition of AC by (lipo)proteins; and (c) the measurement of AC of blood plasma (lipo)proteins can possibly serve to detect the existence and extent of oxidative stress in human organism.

Amino Acids↗
PubMedDate not supplied

Photochemiluminescent detection of antiradical activity. VII. Comparison with a modified method of thermo-initiated free radical generation with chemiluminescent detection.

The method of photosensitized chemiluminescence (PCL) allows the quantification of water- and lipid-soluble antioxidants and activity of superoxide dismutase (SOD) in the same measuring system. However, it needs a special device, which we have described in a previous paper in this series. Another method suitable for the assay of water- and lipid-soluble antioxidants is the thermo-initiated decay of azo-compounds combined with the measurement of O2 consumption (Niki, 1985; Wayner et al., 1985). Its long duration and the complicated measuring procedure is not acceptable for routine medical applications. We show that a modification using CL detection of free radicals with luminol, has results comparable with PCL for the determination of non-enzymic water- and lipid-soluble antioxidants, SOD activity and oxidative modification of proteins. In contrast to PCL, it is possible to use any luminometer with a heatable measuring cell and to investigate coloured samples. While the new method has an overall higher sensitivity and is scalable to microtitre plates, PCL measurements can be made at different pH. The advantages and analytical information content of certain components of the integral antioxidative capacity of blood plasma are discussed in comparison with other methods.

Ascorbic Acid↗
PubMedDate not supplied

High-dose anthracyclines in the treatment of advanced primitive neuroectodermal tumors in adults--a single institution experience.

Primitive neuroectodermal tumors (PNET) are rare malignancies of presumed neural crest origin, most often presenting as bone or soft tissue masses in the trunk or axial skeleton, in children and young adults. Treatment of advanced PNET in adults is not clearly defined in the literature. Data concerning dose-intensive chemotherapy regimens for poor-risk patients with those tumors are sparse, due to rarity of PNET in adults, their diverse presentation, the variable treatment procedures applied and the absence of direct comparisons. On the other hand, the role of anthracyclines in the treatment of advanced soft tissue sarcomas is well known and substantial. Six advanced PNET patients were treated at the Institute for Oncology and Radiology of Serbia, during last five years, with high-doses of doxorubicin or epidoxorubicin combined with cisplatin. The paper reviews each of our patients, discussing how does chemotherapy influence the outcome in these patients, in context of the feasibility of high-doses of anthracyclines in advanced settings. High dose anthracyclines (epidoxorubicin 150 mg/m2) in combination with cisplatin 120 mg/m2 induced a complete response lasting for 63+ months in a patient with desmoplastic medulloblastoma of the cerebellum metastatic to bones and bone marrow. The same treatment but with the epidoxorubicin dose of 180 mg/m2 induced a complete response in a patient with olfactory neuroblastoma. Administration of high dose Doxorubicin (75 mg/m2) seems feasible in association with irradiation treatment in patients with extraosseal Ewing sarcoma/PNET but the place of high dose chemotherapy within this setting remains to be determined.

Adult↗