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Biomedical subjects

J Cejková

Publications and source records attributed to J Cejková.

At least 37 records · Page 2Linked to original sources
PubMed1993

Biochemical and histochemical studies of plasminogen activator of urokinase type (u-PA) activity. I. A simple rapid semiquantitative fluorescent method for its detection in the tear fluid.

A simple rapid fluorescent method for the detection of plasminogen activator activity of urokinase type (u-PA) in the tear fluid is described. Small filter paper punches were soaked in the substrate solution (Z-Gly-Gly-Arg-trifluoromethylcoumarinyl-7-amide, 1 mg/1 ml) and aprotinin 100 micrograms/1 ml) dissolved in 0.1 M Tris-HCl buffer, pH 7.2 and dried. The dried punches were soaked with tears (by direct contact of the punch with the site where the activity should be assessed or by dropping of 3-5 microliters of tears collected by a glass micropipette). The punches were incubated in a thermostat (37 degrees C) together with punches containing a known u-PA activity (calibrated punches) in preheated (37 degrees C) Petri dishes. In 1 min intervals (during the first 15 min) and in 5 min intervals thereafter the probes were exposed to UV light, and the time of the first appearance of a bright yellow fluorescence was recorded. In punches containing 5 IU u-PA activity fluorescence appeared after 2 min incubation; 2.5 IU were detected after 5 min, 1.25 IU after 15 min, 0.625 IU after 30 min, 0.313 IU after 60 min, 0.156 IU after 90 min, and 0.078 IU after 120 min incubation. This simple method is recommended for use particularly in clinical laboratories. It enables e.g. to obtain a rather quick information about the urokinase activity in the tear fluid and to start the treatment with an appropriate inhibitor, if necessary.

Amino Acid Sequence↗
PubMed1992

Histochemical changes in the rabbit cornea and plasmin activity in the tear fluid during contact lens wear. Favourable influence of protease inhibitors (aprotinin, PC5, elastatinal).

Plasmin activity in the tear fluid of the rabbit eye was examined during the wearing of soft contact lenses (SCL) and compared with the occurrence of corneal disturbances assessed in cryostat sections. Plasmin activity was determined with a semiquantitative method using dry punches of filter paper previously soaked in 0.1 M Tris-HCl buffer solution containing mmol/l D-Val-Leu-Lys-FCA (trifluoromethylaminocoumarine), pH 7.2. Punches were applied to the corneal surface for 5 s (tear collection) and incubated in wet chamber. The time of appearance of the bright yellow fluorescence in UV light was recorded and taken as a measure of plasmin activity. For calibration punches soaked in solutions containing plasmin in various concentrations, and processed in the same manner were used. Changes in the cornea were examined histochemically using methods of choice for acid glycosidases, proteases, dehydrogenases, and Na(+)-K(+)-ATPase. SCL with high and low water content were worn in rabbits in 1, 2, 4, 7, 14, 21 and 28 days. Decreased activity of Na(+)-K(+)-ATPase, GGT, and SDH in the corneal endothelium and epithelium were not accompanied by detectable plasmin activity in the tear fluid. Pronounced damage of the corneal epithelium (increased activities of acid glycosidases, acid proteases, LDH, markedly decreased activity of SDH) was accompanied by low concentration of plasmin (0.4-1.0 micrograms/ml) in the tear fluid. Middle activity of plasmin (1.0-2.0 micrograms/ml) was detectable when PMNs were present in the corneal stroma. High plasmin activity (2.0-3.0 micrograms/ml) correlated with corneal ulceration and vascularization.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

[A simple method for detection of P fimbriae in uropathogenic strains of E. coli].

The PF test of the Finnish firm Orion is used for detection of P fimbriae in E. coli strains. Its principle involves the establishment of a chemically defined receptor for these fimbriae on latex particles which can then be agglutinated by the appropriate strains. By means of this test the authors examined 453 uropathogenic E. coli strains. P fimbriae were detected in 121 strains, i.e. in 26.7%. Twenty-five strains agglutinated not only latex particles coated with receptor but also non-coated control particles. The test was thus falsely positive in 5.5% of the cases. Fifty-five strains, where by means of the PF test fimbriae were detected, were examined by the method of mannoresistent haemagglutination of human erythrocytes on a slide. The erythrocytes agglutinated in the presence of d-mannose of all 55 strains, and thus the results agreed in 100%. This suggests that P fimbriae can be detected by the haemagglutination method, but it must be taken into account that this method can, contrary to the PF test, detect also other adhesins. The PF test is very quick, simple and its principle ensures a high reliability.

Escherichia coli↗
PubMed1991

[Uropathogenic strains of Escherichia coli].

In 753 uropathogenic strains of E. coli isolated from urine of patients with urinary tract infections in two localities the authors assessed O and H antigen, mannosensitive adhesin and haemolytical capacities. In strains with assessed O antigen and some of the strains where it was not assessed the authors searched for P fimbriae and for orientation for X adhesin. O antigen was assessed using 33 antisera in 52.05% of the strains. A leading position in the group was held by group 06 (12.21% of all strains). The latter was followed by groups 02, 01, 04, 08, 018 and 021 which together accounted for more than one quarter of all strains. In a large number of O groups the authors found more than one H antigen. Mannosensitive adhesin was found, as expected, in the majority of strains (87.25%). Its absence in more than half 050 strains and in almost one third of 01 strains was striking. 37.18% of all examined strains had haemolytic capacities. 61% of all haemolytic strains belonged only to six O antigenic groups 06, 04, 02, 075, 018 and 021. P fimbriae and X adhesin were assessed in 456 strains. The presence of P fimbriae was proved in 27.41% strains, 72% of all strains with P fimbriae belonged to antigenic groups 01, 02, 04 and 06. X adhesin was detected in 8.33% strains. Of these more than one quarter were formed by strains 021. In strains of this antigenic group we did not detect, however, any P fimbriae. The achieved results do not only inform on some properties of uropathogenic strains of E. coli isolated in some parts of our territory; they indicate also that by means of the applied tests it is possible to obtain a very differentiated picture of these strains. This may be used everywhere where it is desirable to search for groups of strains with homogeneous properties or to obtain at least approximate information on their virulence.

Antigens, Bacterial↗
PubMed1989

Histochemical study of alkali-burned rabbit anterior eye segment in which severe lesions were prevented by aprotinin treatment.

Activities of different enzymes (acid glycosidases, phosphatases, Na+ - K+ -dependent ATPase, proteases, dehydrogenases) and acid glycosaminoglycans were studied by histochemical methods in sections of rabbit anterior eye segments after experimental alkali burn and treatment with aprotinin, an inhibitor of plasmin and other serine proteinases. Solutions of sodium hydroxide (0.25-1.0 M) were applied on corneas using 12-mm-diameter plastic tube for 15-60 s. After wiping with cotton and rinsing with tap water aprotinin solutions were applied in saline (in experimental animals) and saline (in control animals) dropwise in 12-h intervals for a month. Within the first two weeks aprotinin was used at a concentration of 5000 IU/ml. During the subsequent two weeks the aprotinin concentration was reduced to 2500 IU/ml. Striking differences in enzyme activities and in the healing between treated and untreated eyes were found. Without aprotinin, ulcers developed in most corneas within 3 weeks and plasmin was regularly demonstrated in tears and in the aqueous. When aprotinin treatment was started within 24 h after the burn, the number of enzymatically active inflammatory cells was significantly lower, not only in the cornea itself but also in the whole anterior eye segment. With aprotinin treatment no ulcerations and no plasmin in tears and the aqueous were observed and the corneas healed within a month. The healing process started from the zone of enzymatically activated corneal cells in the unburned zone at the corneal periphery. In the regenerating epithelium and endothelium high activities of Na+ -K+ -dependent ATPase, gamma-glutamyltransferase, lactate and succinate dehydrogenases appeared very soon.(ABSTRACT TRUNCATED AT 250 WORDS)

Acid Phosphatase↗
PubMed1989

[Comparison of tolerance to hydrophilic contact lenses made of Hema (37% H2O) and Hema-Degma (55%, 65% H2O) in the rabbit eye. I. Changes in corneal transparency due to disturbed hydration].

The authors compared on the rabbit eye the tolerance of hydrophilic contact lenses with equal parameters (0.2 mm central and peripheral thickness, 7.4 radius, 15 mm diameter) with a different degree of hydration (37% H2O-Hema), (55% and 65% H2O-Hema-Degma) during continuous wear for a period of two weeks (1, 2, 3, 4, 7 and 14 days). Special attention was devoted to changes in the transparency of the cornea. Changes of the transparency due to wearing of contact lenses were due to changes of corneal hydration. The cause of increased corneal hydration were metabolic and later also morphological disorders in the corneal endothelium. The activity of Na+-K+-dependent adenosine triphosphatase and gamma-glutamyl transferase were reduced, followed by a change in the shape and size of endothelial cells. Later the activities of both enzymes were reduced also in the epithelium. Keratocytes had reduced alkaline phosphatase and gamma-glutamyl transferase activities. The staining properties of glycosaminoglycans in the stroma remained, however, unaltered, similarly as the activity of acid glycosidases and other investigated lysosomal enzymes. The onset of increased corneal hydration caused by a disorder of the active water ion transport and of metabolites in the cornea depended on the percentage of water in hydrophilic contact lenses. It was observed latest after application of contact lenses with 65% water.

Animals↗
PubMed1989

[Comparison of tolerance to hydrophilic contact lenses made of Hema (37% H2O) and Hema-Degma (55%, 65% H2O) in the rabbit eye. II. Changes in corneal transparency due profound degenerative processes].

The authors investigated on the rabbit eye the effect of long-term continuous wearing (14, 21, 28 days) hydrophilic contact lenses (h. c. l.) with varying degrees of hydration (37%, 55%, 65% water). Long-term wearing of the lenses caused disorders in all corneal layers. These changes are identical in all types of contact lenses, only their onset is earlier and the extent is more marked in contact lenses with a low hydration (37% water). Contrary to epithelial changes in the corneal stroma, the changes are qualitatively different depending on the degree of hydration of the contact lens. Prolonged application of contact lenses with 37% water leads to infiltration of the stroma by inflammatory cells which carry the activities of destructive lysosomal enzymes. The latter are gradually released into tissues and local degenerative processes develop which in some instances culminate by ulceration. Other corneas are vascularized. The described changes in stroma were not found in hydrophilic contact lenses with 55% and 65% water. After prolonged application of highly hydrated contact lenses (65% water) the authors, however, observed uptake of liquid from the upper third of the stroma due to the contact lens which dried on the eye and acted on the cornea as a hypertonic solution. In this subepithelial zone the staining of glycosaminoglycans was reduced, similarly as the enzymatic activities in keratocytes which suggests serious degenerative processes, i. e. disorders in the synthesis of components of the ground substance of the corneal stroma.

Animals↗
PubMed1988

Disturbances in the rabbit cornea after short-term and long-term wear of hydrogel contact lenses. Usefulness of histochemical methods.

The influence of soft contact lenses (SCL) with low (37%, L) and high (65%, H) water content on rabbit corneas was investigated. The lenses were worn continuously for 1, 2, 4, 7, 10, 14, 21 or 28 days. The changes in corneal transparency, hydration and enzyme activities were studied. A slight change in corneal transparency due to higher hydration caused by a decreased activity of Na+-K+-dependent adenosine triphosphatase (Na+-K+-ATPase) in the corneal endothelium is followed by a decrease in the activity of gamma-glutamyl transferase (GGT). Slight morphological disturbances appear within 4 days in animals wearing SCL (L). SCL (H) produce similar changes one week later. Subsequently, the corneal epithelium becomes thinner and changes in the size of corneal endothelial cells are obvious. Disturbances of enzyme activities in cells of all corneal layers are present. In the epithelium highly increased activities of acid glycosidases, acid phosphatase, and dipeptidyl peptidase I and II, in keratocytes decreased activities of alkaline phosphatase and GGT, and in the endothelium decreased activity of Na+-K+-ATPase and GGT were found. These changes are more severe after SCL (L). In this case, inflammatory cells displaying high activities of lysosomal hydrolases appear in the anterior part of the stroma during the 3rd and 4th weeks and local degradation of glycosaminoglycans and proteins takes place. In contrast, after SCL (H) a remarkable thinning of the corneas was observed during extended wear, accompanied by decreased stainability of stromal glycosaminoglycans and highly decreased enzyme activities in keratocytes. The histochemical methods proved very useful in the assessment of lesions caused by a continuous wear of SCL.

Animals↗
PubMed1986

Histochemistry of some proteases in the normal rabbit, pig and ox corneas.

The distribution of activities of membrane aminopeptidases (aminopeptidase M (APM), aminopeptidase A (APA), dipeptidyl peptidase IV (DPP IV), gamma-glutamyltransferase (GGT) and lysosomal exopeptidases (dipeptidyl peptidase I (DPP I), dipeptidyl peptidase II (DPP II)) was investigated in rabbit, ox and pig corneas. Cryostat sections of snap-frozen corneas treated with chloroform-acetone (4 degrees C) were used for the demonstration of membrane-bound enzymes and sections of corneas fixed in 4% paraformaldehyde (4 degrees C) for the demonstration of lysosomal enzymes. In activities of proteases species differences were found. The rabbit cornea was most active, followed by ox and pig corneas. Individual corneal layers reacted differently. Of membrane proteases a high APM activity was found in keratocytes, whereas epithelium and endothelium were negative. On the other hand, APA and GGT were active in the epithelium and endothelium. Their activities in keratocytes were less pronounced. DPP IV activity was demonstrated in some keratocytes beneath the epithelium only. Lysosomal enzymes DPP I and DPP II were active in all corneal layers. The epithelium displayed the highest activity. Differences in activities in the centro-peripheral and epithelio-endothelial directions were found. DPP I, DPP II, and APM were most active in the limbal region in all corneal layers.

Aminopeptidases↗
PubMed1984

Relationship between various concentrations of NaOH and metabolic effects in experimentally burned rabbit cornea. A biochemical and histochemical study.

In order to assess the extent of injury and the response of the cornea to alkali burns, NaOH in concentrations of 0.5, 0.25, 0.1, 0.05, and 0.01 N was applied to rabbit eyes and the histologic and metabolic changes studied. The activities of alkaline and acid phosphatases in homogenates and in cold microtome sections were examined on days 1, 4, and 7 after injury. At all time intervals 0.5 N and 0.25 N NaOH induced a remarkable decrease in enzyme activities. On the other hand, after 0.05 N and 0.01 N NaOH only very slight changes were observed. Using 0.1 N NaOH, both phosphatases decreased on day 4 after treatment and acid phosphatase reached normal values in a week, whereas alkaline phosphatase increased with a maximum on day 7. Its role in synthetic processes during corneal regeneration is discussed. Both histologic and metabolic patterns in the experimentally burned cornea were shown to be a function of NaOH concentration and the duration of contact. The process of re-epithelization of the cornea during healing after 0.1 N NaOH for 1 min is described.

Acid Phosphatase↗