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Biomedical subjects

L Novák

Publications and source records attributed to L Novák.

At least 19 recordsLinked to original sources
PubMed1992

[The effect of low temperatures on biochemical indicators in the blood of calves].

Twenty calves, heifers of the Holstein-Friesian breed and crossbreds with the Slovak Pied breed, were divided into two groups at the average age of 19 days. The trial group was kept outdoors in wooden hutches and the control group was housed in an insulated building. Blood was sampled at the age of 20, 33, 48 and 60 days at the outdoor temperatures of 3 degrees C, -2 degrees C, -5 degrees C and -8 degrees C. The calves kept in hutches where temperatures were always lower than in the insulated calf-house had the higher level of nonesterified fatty acids in all observations. The largest, highly significant difference was determined at the age of 60 days at the outdoor temperature of -8 degrees C (271 mumol/l vs. 224 mumol/l), and the significance of differences was also observed in the first and third blood samplings at the temperatures of 3 degrees C and -5 degrees C. The differences were highly significant in the first group between the first and fourth, and second and fourth samplings. In the calves kept in the insulated building the difference was significant between the first and fourth observation because the content of free fatty acids was also gradually increasing in this case (Tab. I). Glycaemia values were also higher in the calves kept in hutches (Tab. II). The most noticeable (significant) difference was determined at the age of 48 days at the outdoor temperature of -5 degrees C (4.3 mmol/l vs. 3.9 mmol/l). Significant differences within the group were recorded only in calves from the trial group kept in hutches. Insulin concentrations increased gradually with the older age of animals (Tab. II). At the age of 20 days the values were identical in fact in both groups and the highest concentrations were recorded at the age of 60 days. The differences between the groups were not significant, the largest difference was observed at the end of milk feeding period at the age of 60 days (19 microUI/l in calves from hutches and 15.6 microUI/l in calves from the insulated building). Triiodothyronine concentrations decreased from the starting values of 0.8 nmol/l and 0.76 nmol/l in both groups at the age of 33 days to the values of 0.61 and 0.62 nmol/l.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1991

Plasma xanthine oxidase and resistance to hypoxia: effect of purines and alcohol administration.

The administration of allopurinol significantly increased resistance to repeated hypobaric hypoxia, while hypoxanthine decreased it. The administration of adenine or inosine (25 mg/kg) was without effect. The results show pathogenic significance of xanthine oxidase-dependent production of free oxygen radicals in posthypoxic damage. In other experiments, the administration of 50% ethanol (12 ml/kg) by gastric catheter increased plasma xanthine oxidase activity in both rats and hamsters.

Adenine↗
PubMed1991

[The use of CO2 laser in bone surgery].

Authors examined during the trial of a CO2 laser of type TUNGSRAM TLS-61 the possibility of its use in the orthopaedic surgery. The output necessary to cut the skin and bony tissue, the speed of cutting and the extension of tissue necrosis were determined in experiments in vitro and in vivo. According to their observation the fusion of the bone cut with CO2 laser takes the same time as after the traditional osteotomy, however in the first three weeks the callus formation falls behind. The possibility of a curved cutting and of the coagulation haemostasis may ensure a fine prospect to this method.

Animals↗
PubMed1991

[Influence of calcium hydroxide under filling cements].

In the paper lying before the authors estimate changes of pH-values of the Calcium hydroxide (Calxyd) after contact with a zinc oxide phosphate cement (Adhesor), a polyacrylate cement (Adhesor-Carboxy) and a zinc oxide eugenol cement (Caryosan). The last shoved to be best qualified for over capping of pasty preparation with calcium hydroxide.

Analysis of Variance↗
PubMed1991

[Biocompatibility of a chromium-cobalt alloy studied in vitro].

The authors followed the effect of chromcobalt alloy on human cells cultured in vitro. They found out that corrosion increases the cytotoxicity of this alloy, meanwhile the perfectly laboratory elaboration, especially polishing of substitution decreases the cytotoxicity. We recommend for the complex cytotoxicity review, to test the metals and alloys also after laboratory elaboration, it means in the condition it is passed on to the patient.

Biocompatible Materials↗
PubMed1991

[Reaction of HeLa cells to the presence of Evicrol varnish studied by electron microscopy].

The electron-microscopical changes of cells produced by underlying Evicrol varnish are described. The latter is used in preventive stomatology to underlay fillers, those from composite materials, especially. It is designed to prevent the pulp damage through these materials. The changes of in vitro cultivated cells have in contrast been confirmed with previous experimentation showing that the varnish itself causes toxicity for living cells and therefore is not convenient to undercoat cavities in the proximity of pulps.

Dental Materials↗
PubMed1991

[The effect of Aspan on live cells in vitro].

Cytotoxicity of an experimental vitrioionomeric cement Aspan has been proved on the basis of morphological reaction of cells cultivated in vitro. There was no decrease in toxic action of Aspan when recovered with Silfolit and Evicrol varnishes.

Dental Cements↗
PubMed1990

[Treatment of defects of the cervical portion by a "sandwich" filling].

The authors draw attention to some peculiarities of treatment of class V cavities by aesthetic fillings. Combined filling made from silicocarboxyl cement and composite filling material prove useful. In teeth with preserved pulp sandwich fillings are used which contain three layers (base, intermediate retention layer of silicocarboxyl cement and composite material). In pulpless teeth, the base is not needed and the term combined filling (two layers) is more appropriate.

Composite Resins↗
PubMed1990

[Investigations of cytotoxicity of Heliosit depending on its polymerizing in vitro].

In this paper the authors describe the changing in cell culture of epithelioid cells of a permanent HEp-2-line basing on the one component composite Heliosit. Following the experiences with farmer test the authors mean that contact and local toxicity are not so heavy but depending from the polymerization of the materials. Warning is the arretation of some phases in cell cyclus and the changing of epithelioid cells in fibroblastoid cells. May it is a cell transformation necessary to examine in special tests.

Cell Transformation, Neoplastic↗
PubMed1990

Influence of hypoxanthine, allopurinol and adenine on resistance of rats and hamsters to hypobaric hypoxia.

The survival time of rats and hamsters in lethal hypoxia was measured after a sublethal exposure and a normoxia break, at the beginning of which purines were administered intraperitoneally in the following dosages: 25 mg/kg hypoxanthine, 50 mg/kg allopurinol, 25 mg/kg adenine. In rats, administration of hypoxanthine decreased the survival time by 20%, administration of allopurinol increased it by 25%. Oxygen overpressure of 5 kPa between the two hypoxic doses resulted in larger differences after hypoxanthine and allopurinol application as compared to normoxia break. In hamsters, the effect of allopurinol, hypoxanthine and oxygen was similar, but smaller than that in rats. Adenine did not significantly affect the survival time of rats or hamsters. If hypoxia was applied only once, the purines had no effect on the survival time of rats or hamsters. No measurable XOD activity was observed in hamsters, whereas in adult rats, 99.46 +/- 13.85 nkat/l were found.

Adenine↗
PubMed1989

[Reaction of cells cultured in vitro on 2 self-polymerizing adhesives].

Cytopathological changes due to self-polymerizing enamel adhesives Evikrol Bond and Concise Enamel Bond were studied. Both the materials were toxic for in vitro cells. They caused death of the cells and degenerative changes appeared in some organelles including the cell membrane. This resulted in bad adhesion of the cells to the substrate. Extractions of these adhesives caused also changes in the karyoplasm. The observed change of epithelioid HEp-2 permanent line cells into fibroblastoid cells requires, however, further verification by means of special tests.

Acrylic Resins↗
PubMed1989

[Cytotolerance of bioceramics in cell culture studies].

Biological effects of ceramic implant material of Czechoslovak make prepared on the basis of alumina were studied here. The material was proved to be quite inert both toward epithelioid Hep-2 cells and toward L-line fibroblastoid cells in experiments with nonspecific application, i.e., in cell cultures.

Aluminum↗