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Biomedical subjects

J Sulc

Publications and source records attributed to J Sulc.

At least 19 recordsLinked to original sources
PubMed1992

Lung function in atrial septal defect after heart surgery.

Lung volume, indices of lung elasticity and airway patency were measured in 74 patients, 9-21 yr old (15.0 +/- 2.5 yr) with atrial septal defect (secundum type) from 2-11 (5.1 +/- 2.5) yr after successful surgical correction. Clinical condition in all patients was classified as excellent. Heart surgery was performed at the age of 4-14.8 (9.9 +/- 3.0) yr. Lung function abnormalities were found in 35 (47.3%) patients. Lung recoil pressure was significantly increased in 24 (32.4%) patients. The mean value of lung recoil pressure at 100% of total lung capacity reached 123 +/- 31% of the predicted value (P < 0.0001). Specific static compliance was within normal limits. Specific airway conductance was significantly reduced in 13 (17.6%) patients. Maximum expiratory flow at 25% of vital capacity was significantly reduced in 4 (5.4%) patients. Static lung volumes did not differ from reference values. Since various abnormalities of lung function tests (most frequently the tests suggested increased lung stiffness and obstruction of larger airways) were revealed in almost half of the studied children and adolescents after successful surgery for atrial septal defect, we propose to carry out lung function tests routinely as another criterion of health conditions in these patients.

Adolescent↗
PubMed1992

Intermediate to late results of surgical relief of vascular tracheobronchial compression.

Since 1979, a total of 69 infants and children aged 0.1 to 11.9 (median 0.7) years required surgical intervention for: double aortic arch (26), anomalous origin of innominate artery (26), right aortic arch with left ligamentum arteriosum (9), pulmonary artery sling (5), retroesophageal right subclavian artery (3). Before operation, the morbidity was high: 84% of children were symptomatic in the first trimester of life with 24 patients requiring mechanical ventilation. Seven children had an accompanying heart defect. Left thoracotomy was the preferred approach. There were 2 early (asphyxic brain damage, postoperative pneumonia) and 2 late (tracheomalacia, complex heart defect) deaths. Five patients (2 originally operated elsewhere) needed reoperation for persistent symptoms. All 65 survivors are well 1 month to 11.9 (mean 3.9 +/- 3.62) years after surgery. Tracheobronchoscopy, magnetic resonance imaging, and lung function testing were helpful for postoperative evaluation. Minor tracheal compression was revealed in 4 patients despite their good clinical condition.

Airway Obstruction↗
PubMed1991

[Submicroscopic structure of amniotic fluid cells].

Submicroscopic examination of amniotic fluid cells in the second trimester of pregnancy revealed that the cells are from the morphological aspect a very heterogeneous population, comprising vital and degenerated cells the ultrastructure of which rules out the possibility of cultivation of cells of foetal as well as of maternal origin. As to degenerated cells, the authors identified circular cells with a granular cytoplasm and nucleus originating from the urogenital or digestive tract of the foetus. Furthermore cells with a process and segmented or fragmented pycnotic nucleus derived from granulocytes and macrophages of maternal origin. Also circular cells of the periderm with short microvilli and advanced regressive changes of the nucleus and cytoplasm are degenerated. Among non-vital elements also anuclear completely keratinized cells of the stratum corneum originating from the skin of the maternal abdomen can be included. As to vital elements, the amniotic fluid contains cells of the amniotic ectoderm which are large, have numerous microvilli, a dense margin and a network of filaments in the cytoplasm. They are the most numerous cells. Other vital elements in amniotic fluid include granulocytes and macrophages with a typical ratio of lyzosomes. Both are considered elements of maternal origin. Maternal origin is assumed also in fibroblasts which along with collagen particles may penetrate into the aspirating needle. From the results ensues that the cells in amniotic fluid are not a homogeneous population of unequivocally foetal origin and that a better technique of collection of samples and cultivation must be developed.

Amniotic Fluid↗
PubMed1991

[Visual function requirements in modern aviation].

The authors describe aviation ophthalmology as a typical ergoophthalmic discipline as regards the sphere of interest as well as with regard to its preventive trend. The visual analyzer is a very exposed sense which can be modified by some dynamic effects of flight to such an extent that they may restrict the pilot's activities and consequently also the safety of the flight. Specific factors of flight which comprise also aerogenic hypoxia, hypobarism, overloading, vibrations and the consequences of impaired relations of the different senses may be manifested by changes of the perception of light, colour, visual acuity, perception of contrasts of the visual field etc. The most modern aviation technique puts some so far unusual demands on vision tested by means of complicated psychophysiological tests. Only the future will show which tests should be included among routine methods of aviation ophthalmology and which tests will be restricted only to experimental work.

Aerospace Medicine↗
PubMed1990

The influence of hydrogel functional groups on cell behavior.

This study provides information on the behavior of macrophages on the surface of the subcutaneously implanted hydrogel strips. Hydrogel containing -OH, -CO-NH-, and (CH3)2N- groups induced a spreading of macrophages on the implants. The materials containing -SO3H groups slightly, and materials containing -COOH groups more intensively, inhibited spreading of the macrophages. The fusion of macrophages into multinucleate cells was inhibited on the surface of materials containing acidic groups (-SO3H, -COOH) and increased on the hydrogels containing 30 mol% of alkaline (CH3)2N- groups in comparison with hydrogels containing -OH or -CO -NH- groups. The differences of the behavior of macrophages on the surface of individual types of hydrogels are probably independent on the adsorption of plasma fibronectin onto the hydrogels. The correlation between the macrophages spreading and fusion and surface charge of the hydrogel implant can be hypothetically explained by electrostatic interaction between macrophages cell membrane and implant.

Animals↗
PubMed1990

Silicone rubber-hydrogel composites as polymeric biomaterials. II. Hydrophilicity and permeability to water-soluble low-molecular-weight compounds.

The surface and transport properties of water-swollen silicone rubber-hydrogel composites were investigated. Surface wettability of these materials, composed of a polysiloxane matrix and the hydrogel phase consisting of very fine particles of lightly cross-linked poly(2-hydroxyethylmethacrylate), increased markedly with increasing content of the hydrogel phase. For composite materials containing a lightly cross-linked 2-hydroxyethylmethacrylate (HEMA)-methacrylic acid (MAA) copolymer and polymethacrylic acid (PMAA) as the hydrogel phase, permeability to water-soluble organic compounds and drugs were measured. The permeability varied within a broad range depending on the composition and content of the hydrogel phase. High permeation rates could be obtained while still retaining relatively fair mechanical properties. Relationships between the composition of silicone rubber-hydrogel composites, their structure and the permeation coefficients of the individual permeates are discussed.

Biocompatible Materials↗
PubMed1989

Lung function in simple complete transposition after intracardiac repair.

Pulmonary function was measured in 35 patients (mean age 11.6 years) with simple complete transposition 4.4 years after intracardiac repair. A disturbance in the lung function (greater than 2 SD from the normal value) was found in 88% of the patients. A marked increase in static recoil pressure (P less than 0.001) was most frequent (in 66%). Static lung compliance was only 75.1% of the predicted values. Values of mean vital and total lung capacity were decreased (P less than 0.01 and 0.001). Residual volume, the ratios of functional residual versus total lung capacity and residual volume versus total capacity were all increased. The signs of decreased patency of the airways were found in only 4 patients. A negative correlation was detected between the indices of lung stiffness and the age of assessment of lung function. A positive correlation was found between the ratios between functional residual and total capacity and pulmonary blood flow. No other correlation between lung function data and pulmonary arterial pressure or flow was proved. Increased lung stiffness, restriction of lung volume and hyperinflation could influence unfavorably the long-term results in successfully treated patients with simple complete transposition.

Adolescent↗
PubMed1989

Influence of thyroid hormone supply on EEG frequency spectrum.

In 5 patients after total thyroidectomy followed by radioiodine ablation the frequency analysis of EEG based on fast Fourier transformation was performed and the results obtained during hypothyroid state and after the substitution treatment with thyroid hormones were compared. During the hypothyroid state the most remarkable finding was the increase of percentage representation of fast frequencies in beta 1 and beta 2 bands, while such values in alpha band including a dominant frequency in that band were reciprocally decreased. After the period of treatment with triiodothyronine during which clinically euthyroid state has been achieved (i.e. decrease of Achilles tendon reflex time, decrease of TSH and of T3 level) no significant changes in the distribution of EEG frequencies spectrum were found, but in all patients a dominant frequency in alpha band was increased at least for 1 Hz. Only after the treatment with thyroxine (Eltroxin Glaxo) the interrelations between individual frequencies of EEG spectrum returned to the normal range and a further increase in dominant alpha frequency was found. The correlation between a dominant frequency in alpha band and thyroxine level in serum was highly significant. These findings are in agreement with our previous observations in 43 subjects where a dominant alpha frequency in healthy controls was always higher than that in hypothyroid subjects and was significantly related to T4 level. The findings of continuing EEG signs of brain hypothyroidism even after achieving of clinical euthyroidism and normal peripheral parameters under increased serum T3 and low T4 level are in full agreement with experimental observations on the importance of local deiodination of T4 in brain tissue and on the risk of hypothyroxinemia.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1989

[Experimental implantation of hydrogel into bone].

In spite of the rapid development of various natural and artifical implants of bone tissue, bones or whole joints, no material was found as yet which would maximally resemble the structure of the bone tissue and would also be maximally compatible. The present study deals with the application possibilities of unsoluble hydrophilic gels (hydrogels) as substitutes of bone tissue in experiment. The study concerns above all their biocompatibility with regard to the porous qualities of the implant and to its chemical structure, and evaluates their behaviour in the spongious and compact bone. It was used polyhydroxyethylmethacrylate (polyHEMA) which is crossling with small amount of glycoldimethacrylate when by changing of ratio monomer: water is possible obtain from homogeneous to macroporous structure of polymers. The macroporous structure was increased and the surface of the macroporous structure of polymers. The macroporous structure was increased and the surface of the macroporous, sinterted HEMA modified and implanted. The so-called double porosity was thus obtained. The implants were prepared in the form of cylinders (3.5 mm in diameter) in 8 different modifications and surgically implanted into the subtrochanteric and supracondylic part of the rabbit femurs. 42 animals were operated on. The obtained preparations were then evaluated macroscopically, and histologically processed in half-thin cuts (3-4 micrones). 124 samples were thus obtained. Some samples were radiographically contrasting. The rabbits were killed at intervals from 1-6 months, i.e. 32-193 days. It was found that the hydrogels modifications used in the experiment are biocompatible, their compatibility increasing in dependence on the increasing porosity. The non-porous and microporous hydrogels are not compatible and are damarked. The sintered macroporous gel is surrounded by a thin fibrine membrane signifying a high degree of compatibility with the bone tissue. By adding metacrylate acid to the hydrogel, the adhesivity of the macrophages increases markedly. There also appears the destruction of the polymer, marked, above all, in the spongious bone. The gel is actively degraded in the marrow, although the direct phagocytosis can be proved. At degradation of the implant in the compact bone the activity of the macrophages is belated; at application of the gel without methacrylate acid it does not occur even after 193 days and the implant is pervaded only by the bone beams. When adding methacrylate acid to the polymer degradation occurs, in which process there play also an active role the blood vessels pervading the site of the gel implantation.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1987

Intraocular biocompatibility of hydroxyethyl methacrylate and methacrylic acid copolymer/partially hydrolyzed poly(2-hydroxyethyl methacrylate).

A strip of partially hydrolyzed poly (2-hydroxyethyl methacrylate) containing 65%-75% H2O was implanted into the anterior eye chamber of 11 Chinchilla rabbits. No pathological changes were found in the iris or in the ciliary body. The pathological findings in the cornea accompanying implantation of a hydrogel strip to the anterior chamber were rare and not significant. The low occurrence of the foreign body giant multinucleate cells was observed on the implant surface 6 months after the implantation. Favorable properties of this hydrogel depend probably on its high water and acidic groups content.

Acrylates↗
PubMed1987

Physicochemical aspects of the giant multinucleate cell formation.

Process of multinucleate cell formation was studied under two conditions: (1) during the perichondral ossification of the chick embryonal tibia, and (2) in foreign-body reaction against polyhydroxyethylmethacrylate (POLYHEMA) and copolymer of hydroxyethylmethacrylate and methacrylic acid (POLYHEMA-MA) subcutaneously implanted into the rat. Multinucleate cells covered a surface of the substrate with relatively low hydrophylia and with low or without acidic groups (mineralized bone and POLYHEMA). On the other hand, no (POLYHEMA-MA) or only exceptional (nonmineralized resorbed cartilage) multinucleate cells were visible on the substrate rich in water and acidic groups. This similarity is not surprising, since it is accepted that both cell types represent a specialized phagocytic element. These results demonstrate that precursor cells can fuse only under convenient conditions. Forces analogous to hydrophobic and electrostatic interactions probably participate in this process.

Animals↗