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Biomedical subjects

N Skuba

Publications and source records attributed to N Skuba.

8 recordsLinked to original sources
PubMed2006

Poly(2-hydroxyethyl methacrylate) microspheres/liquid poly(dimethylsiloxane) composition for correction of small defects in face: histological evaluation in animal experiment.

Two kinds of composition based on commercial liquid poly(dimethylsiloxane) and laboratory-made poly(2-hydroxyethyl methacrylate) (PHEMA) microspheres of different size fractions (30-40 or 125-180 microm) were prepared. Tissue reaction on injection of the compositions, optimum microsphere size and morphology were investigated in the experiments on rats. The microspheres induced foreign body reaction characterized by an increased content of fibroblasts and mild infiltration of injection field by inflammatory cells. The 125-180 microm microspheres seemed to be well covered with poly(dimethylsiloxane) and more uniformly distributed in the tissue than the 30-40 microm ones. As a result, the extent of foreign body reaction induced by the former microspheres was somewhat lower than that induced by the latter. Moreover, time-dependent degradation of 30-40 microm PHEMA microspheres was more pronounced than that of 125-180 microm ones, which can affect duration of the aesthetic effect after prospective facioplasty. Results of histological investigations demonstrate a good prospect of the proposed composition for contour and bulk facioplasty of small soft tissue defects and skin wrinkles.

Animals↗
PubMed2000

Targeted chemoembolization of tumors with poly(2-hydroxyethyl methacrylate) particles.

Thirty-four patients suffering from various kinds of tumors, including metastasis, were treated by selective embolization with both spherical and cylindrical poly(2-hydroxyethyl methacrylate) [poly(HEMA)] particles and topical chemotherapy. Treatment of a patient with carcinoid metastases in the liver is discussed. Immediately after embolization, 5-fluorouracil, and later, doxorubicin and Lipiodol, were selectively infused into the tumorous tissue for approximately 1 week. Patient received four cycles of this infusion. Chemoembolization proceeded against the background of anticoagulant therapy using small doses of heparin or its low-molecular-weight analogue, dalteparin. This was followed by transcutaneous transhepatic portography and embolization. Finally, the tumor-feeding artery and portal vein were sealed by a hydrogel. After 1.5 months, the affected liver lobe was resected. Although 4 years from the beginning of treatment, the patient is still alive. Embolization with poly(HEMA) hydrogel particles in conjunction with an anticancer drug infusion via catheter is recommended as an efficient method of tumor treatment. The therapeutic effect has been shown to be a function of ischemia and slow local infusion of drug into the tumor, and systemic drug levels can be kept low.

Anticoagulants↗
PubMed1992

Hydrogels in endovascular embolization. V. Antitumour agent methotrexate-containing p(HEMA).

The aminohexyl derivative of the copolymer of 2-hydroxyethyl methacrylate and ethylene dimethacrylate (p(HEMA)-Hex) in the form of regular spherical particles was used as a polymeric carrier for chemically sorbed methotrexate (MTX). The effect of the washed p(HEMA)-Hex-MTX carrier on the morphological structure of donor blood, on blood coagulation indicators and on responses of the living tissue surrounding the material which has been in the blood vessel of the rabbit for various periods of time was evaluated. MTX is capable of diffusion for several days from the embolic material.

Animals↗
PubMed1992

Haemostatic activity of ethamsylate and aminocaproic acid adsorbed poly(2-hydroxyethyl methacrylate) particles.

A haemostatic material suitable for embolization was prepared by the adsorption of haemostatics--ethamsylate and aminocaproic acid in the spherical particles of porous poly(2-hydroxyethyl methacrylate) (p(HEMA)). The degree of purification of ethamsylate-treated particles was tested by an analysis of donor blood in contact with the material. An evaluation of the haemostatic properties of these materials was obtained by the determination of the indicators of blood clotting: activated partial thromboplastin time, thrombin time, and prothrombin time. Ethamsylate or aminocaproic acid-containing p(HEMA) has a distinct haemostatic effect on pathological blood of patients suffering from focal alterations of the liver. These haemostatic emboli materials show promise for the immediate control of various haemorrhages; when introduced into a zone with increased haemorrhage, they may help to correct disturbed haemostasis.

Adsorption↗
PubMed1988

Hydrogels in endovascular embolization. IV. Effect of radiopaque spherical particles on the living tissue.

In this study we report the results of toxicological, histological and haematological experiments on radiopaque spherical particles based on poly(2-hydroxyethyl methacrylate). These particles have been developed for endovascular occlusion of various organs. Radiopacity was attained by two independent methods: the chemical attachment of radiopaque substances to the hydrogel or the precipitation of radiopaque substances in the hydrogel network. The first method yields particles that appear to have uniformly-distributed contrast material, but in the particles prepared by the second procedure the contrast material is predominantly located on the surface. The visibility of such particles by X-rays makes possible controlled embolus introduction and inspection of the polymer for long periods after embolization. Radiopaque contrasting changes the morphology and reduces the porosity of the material but supports quick thrombus formation. Embolic material implanted in rabbits becomes surrounded by a thin fibrous capsule and undergoes partial organization. This and other results of medico-biological investigations have fully demonstrated the biocompatibility of radiopaque spherical emboli, which can now be used clinically.

Animals↗
PubMed1986

Hydrogels in endovascular embolization. I. Spherical particles of poly(2-hydroxyethyl methacrylate) and their medico-biological properties.

Spherical macroporous particles based on poly(2-hydroxyethyl methacrylate) with defined porosity, swelling and morphology have been developed, and are suitable for endovascular occlusion of various organs. Unlike cylindrical particles, spherical particles are specifically suited for transcatheteral introduction. The method chosen for the preparation of such particles was suspension radical polymerization, where the monomers were dissolved in a mixture of higher-boiling alcohols, and the solution dispersed in water. Physicochemical and medico-biological properties of spherical particles were examined. The residual amounts of monomers and other low-molecular compounds were checked; haematological analyses showed that the value 10(-5) g/g of the polymer was not toxic and contributed to an irreversible aggregation of thrombocytes. The occlusion effect in the vascular lumen was stable. The histomorphological results fully demonstrated the perfect biocompatibility of artificial spherical emboli. The latter met the requirements of application to clinical practice.

Animals↗