Biomedical subjects

S M Ivanov

Publications and source records attributed to S M Ivanov.

12 recordsLinked to original sources

PubMed2005

Effect of mixing on reaction-diffusion kinetics for protein hydrogel-based microchips.

Protein hydrogel-based microchips are being developed for high-throughput evaluation of the concentrations and activities of various proteins. To shorten the time of analysis, the reaction-diffusion kinetics on gel microchips should be accelerated. Here we present the results of the experimental and theoretical analysis of the reaction-diffusion kinetics enforced by mixing with peristaltic pump. The experiments were carried out on gel-based protein microchips with immobilized antibodies under the conditions utilized for on-chip immunoassay. The dependence of fluorescence signals at saturation and corresponding saturation times on the concentrations of immobilized antibodies and antigen in solution proved to be in good agreement with theoretical predictions. It is shown that the enhancement of transport with peristaltic pump results in more than five-fold acceleration of binding kinetics. Our results suggest useful criteria for the optimal conditions for assays on gel microchips to balance high sensitivity and rapid fluorescence saturation kinetics.

Diffusion↗

PubMed2005

[Thermoradiotherapy as a component of desmoid tumor management: 10-year experience].

Data on radio- and thermoradiotherapy of 83 patients with extra-abdominal desmoid tumors are discussed. In a group of 57 patients followed up for 10 years or less, the relapse-free survival rates, in thermoradiotherapy-treated cases, were significantly higher (74.4% and 28.6%) than in those receiving radiotherapy (9.3% and 57.1%). Monitoring tumor temperature during local hyperthermia is a factor of relapse-free survival of vital importance.

Disease-Free Survival↗

PubMed2005

[Thermoradiochemotherapy of inoperable soft-tissue sarcoma].

Three groups of patients with inoperable soft-tissue sarcoma received preoperative radiotherapy (57), thermoradiotherapy (102) and thermoradiochemotherapy (16) (n=175). Five year recurrence-free survival in group 1 was 37+/-7%, group 2 48+/-6%, and group 3 - 56+/-1,7%. Patients survived 5 years and more in group 3 (60+/-2%), group 2 - 50+/-7%, and group I 44+/-8% (p>0.05). Local hyperthermia used in conjunction with radio- and chemoradiotherapy was followed by a significant rise in the rate of complete and partial tumor regression.

Adult↗

PubMed2005

[Radiotherapy as a component of treatment for Ewing's sarcoma].

The main stages of development of such conservative modalities as radio- and chemoradiotherapy for localized Ewing's sarcoma are discussed. Factors affecting five-year overall and recurrence-free survival of patients treated with chemoradiotherapy are presented.

Adult↗

PubMed2005

[Results of repeat large-scale dissection of soft-tissue sarcoma following non-radical removal].

The reports deals with the data on repeat large-scale dissection of soft-tissue sarcoma following non-radical removal in 23 patients (13 males and 10 females , aged 14-75; mean age 42+/-30.2 yrs). Repeat surgery was carried out 3-6 weeks after primary one. Tumor progression was registered in 8 (34.8%): local recurrences which required radical intervention 4 (17.4%), distant metastases - 6 (26.1%) (lung - 3; liver - 1; lung and mediastinal lymph nodes - 1; lung and lumbar vertebra - 1). During the study, 5 patients died of tumor progression; all of them revealed distant metastases while 2 had local recurrences. Overall 5-year survival in 23 patients was 78%; whereas disease-free one - 65%.

Adolescent↗

PubMed2003

Hydrogel-based protein microchips: manufacturing, properties, and applications.

Here a simple, reproducible, and versatile method is described for manufacturing protein and ligand chips. The photo-induced copolymerization of acrylamide-based gel monomers with different probes (oligonucleotides, DNA, proteins, and low-molecular ligands) modified by the introduction of methacrylic groups takes place in drops on a glass or silicone surface. All probes are uniformly and chemically fixed with a high yield within the whole volume of hydrogel semispherical chip elements that are chemically attached to the surface. Purified enzymes, antibodies, antigens, and other proteins, as well as complex protein mixtures such as cell lysates, were immobilized on a chip. Avidin- and oligohistidine-tagged proteins can be immobilized within biotin- and Ni-nitrilotriacetic acid-modified gel elements. Most gel-immobilized proteins maintain their biological properties for at least six months. Fluorescence and chemiluminescence microscopy were used as efficient methods for the quantitative analysis of the microchips. Direct on-chip matrix-assisted laser desorption ionization-time of flight mass spectrometry was used for the qualitative identification of interacting molecules and to analyze tryptic peptides after the digestion of proteins in individual gel elements. We also demonstrate other useful properties of protein microchips and their application to proteomics and diagnostics.

Equipment Design↗

PubMed1999