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Biomedical subjects

Z Lojda

Publications and source records attributed to Z Lojda.

At least 37 records · Page 2Linked to original sources
PubMed1995

Effect of domperidone-induced hyperprolactinemia on selected immune parameters in healthy women.

Domperidone, anti-emetic drug, given to healthy female volunteers, induced an elevation of plasma prolactin (PRL) concentration with the peak in 1-4 h. The release of prolactin had a transient stimulating effect on theophylline sensitive T lymphocytes and on concanavalin A induced mitogenic activity, suggesting an enhanced activity of T suppressor lymphocytes. The relative number of CD4+ lymphocytes decreased markedly one hour after domperidone administration and returned to normal values within 2 h (that means 3 h after taking the drug). The number of lymphocytes positive for dipeptidyl peptidase IV exhibited similar transient increase and normalization of activity. No change was observed in the number of CD8+ lymphocytes. The production of interferon by leukocytes treated with Newcastle disease virus was found to be significantly increased 2 h after domperidone administration. The results suggest that prolactin can selectively stimulate some functions of cellular immunity as well as the release of cytokines (IFN). The present study may contribute to the understanding of the role of the immune system in endogenous hyperprolactinemia.

Adolescent↗
PubMed1994

The damaging effect of UV rays (with the wavelength shorter than 320 nm) on the rabbit anterior eye segment. I. Early changes and their prevention by catalase-aprotinin application.

In experiments carried out in rabbit eyes, UV rays of 254 or 312 nm wavelength damaged the anterior eye segment, whereas those of 365 nm wavelength did not. Two min irradiation with 254 nm UV rays led to a decrease of catalase activity in the corneal epithelium. After 5 min irradiation the catalase activity in the epithelium was not detectable at all. Catalase activity was also diminished in the corneal endothelium and lens epithelium. In this stage the changes were accompanied by decreased activities of Na(+)--K(+)-dependent adenosine triphosphatase, gamma-glutamyl transpeptidase and increased activities of lysosomal enzymes in the corneal and lens epithelium as well as in the corneal endothelium. The transparency of the cornea and lens was decreased. Plasmin activity appeared in the tear fluid. The irradiation with UV rays of 312 nm caused similar disturbances, however, a longer exposure was necessary. In contrast, irradiation with UV rays of 365 nm did not produce any changes. The described corneal disturbances were prevented by dropping of catalase solution on the eye surface during the irradiation or shortly after it. However, after a protracted irradiation aprotinin had to be added to catalase to achieve the healing. The decrease of catalase activity and its prevention by a local application of catalase suggests a key role of oxyradicals in the damage of the eye by UV rays.

Animals↗
PubMed1994

Application of NADH tetrazolium reductase reaction in perioperative biopsy of dysganglionic large bowel.

A reaction for NADH tetrazolium reductase was used to demonstrate the presence of ganglion cells in myenteric plexus during dysganglionic bowel operations in 24 patients. The advantages of this method are the quick preparation of an incubation medium, a short incubation time and the good demonstration of ganglion cells. It was possible to determine the extent of the aganglionic and prominently hypoganglionic parts of the bowel and in this way achieve improved results. The NADH tetrazolium reductase reaction can be recommended for the perioperative biopsy of a dysganglionic bowel.

Biopsy↗
PubMed1993

The histochemical pattern of mechanically or chemically injured rabbit cornea after aprotinin treatment: relationships with the plasmin concentration of the tear fluid.

Plasmin, a serine protease, was recently found to be involved in corneal ulcerative processes in humans and rabbits. In our experiments, plasmin activity was found in the tear fluid after mechanical and chemical damage of the rabbit cornea, such as de-epithelization and burning with alkali. The plasmin concentrations in the tear fluid were dependent on the severity of injury. The highest plasmin activity (2.0-3.0 micrograms ml-1) occurred after severe alkali damage to large areas of the cornea, and the lowest activity (0.4-1.0 micrograms ml-1) after mechanical injury (de-epithelization). Plasmin concentrations up to 1.0 micrograms ml-1 were associated with increased activities of lysosomal hydrolases in epithelial cells and keratocytes beneath the epithelium. Plasmin activities increased as the inflammatory reaction developed. When plasmin activity in the tear fluid was higher than 1.0 micrograms ml-1, inflammatory cells were found in the corneal stroma. Levels of 1.5-2.0 micrograms ml-1 were connected with higher numbers of inflammatory cells (particularly polymorphonuclear leukocytes) with increased activities of lysosomal hydrolases. Very high plasmin activities (2.5-3.0 micrograms ml-1) accompanied corneal ulcerative processes. The local application of aprotinin (Trasylol, Bayer), an inhibitor of plasmin, and also of some other proteases, was found to be necessary for the healing of severe corneal injuries in which highly elevated plasmin activity in the tear fluid and inflammatory cellulization of the cornea occurred (severe damage).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
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↗
PubMed1993

Morphometrical histochemical and biochemical parameters in the dog alloxan diabetes.

Changes of morphometrical, biochemical, histochemical and immunohistochemical parameters were investigated in the alloxan diabetes in the dog. Samplings of material for electron microscopical and histochemical examinations were performed in 3 month period (4 times). A significant thickening of capillary basement membranes in the striated muscle (vastus lateralis) was ascertained even in the dog with glucose intolerance only. In this mentioned case a decrease of glucoso-6-phosphatase activity was observed. Evaluation of different types of muscle fibres assigned an increase of slow twitch fibres or intermediate ones respectively.

Animals↗
PubMed1993

[Histochemical and immunohistochemical study of jejunal mucosa cells in children with celiac sprue].

In the jejunal mucosae of 45 children with coeliac sprue (24 cases in the florid stage and 21 cases in remission) and 19 children without signs of affection of the small intestine a quantitative investigation was made of cells in the lamina propria which were visualized selectively by histochemical and immunohistochemical methods-plasmocytes with IgA, plasmocytes with IgM, plasmocytes with IgG, cells containing IgE, mast cells, eosinophil and neutrophil leucocytes. The objective was to find which of the above cells will best reveal by a change of their number the pathological process in the lamina propria of children with coeliac sprue and which has the greatest informative value on the present state of the lamina propria. It was found that plasmocytes with IgG and cells containing IgE are good markers of the activity of coeliac sprue in the lamina propria. The best marker of the activity of coeliac sprue in the lamina propria are mast cells detected by the histochemical reaction for tryptase using Z-Ala-Ala-Lys-MNA. This reaction detects mast cells also in non-fixed bioptic material.

Adolescent↗
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↗
PubMed1992

Aminopeptidases in the circumventricular organs of the mouse brain: a histochemical study.

The localization of four membrane-bound aminopeptidases--aminopeptidase A, aminopeptidase M, dipeptidylpeptidase IV, and gamma-glutamyl transpeptidase--known as characteristic enzymes of the blood-brain barrier was studied in the microvasculature of some circumventricular organs of the mouse brain (subfornical organ, area postrema, choroid plexus, and neurohypophysis). Enzyme activities were demonstrated histochemically in chloroform-acetone-pretreated cryostat sections applying an azo-coupling method. Reactions were evaluated using light microscopy and end-point microdensitometry. The results revealed differences in microvascular enzyme pattern between circumventricular organs and regions having a blood-brain barrier. Moreover, the cytochemical picture of the circumventricular organs themselves was not uniform. Dipeptidylpeptidase IV reaction showed a strongly reduced activity in the microvessels of all studied circumventricular organs. On the other hand, aminopeptidase M seemed to be present in both the leaky and the tight capillaries. Only a low activity of aminopeptidase A was found in parts of the choroid endothelium and the subfornical organ microvasculature. gamma-Glutamyl transpeptidase could neither be detected in the capillary part of the choroid plexus nor in the neurohypophysis. We are led to conclude that at least dipeptidylpeptidase IV might be involved in special mechanisms of the blood-brain barrier.

Aminopeptidases↗
PubMed1992

Enzymatic equipment of the developing human eye.

The activities of a number of enzymes seen in adults and in animal material were found in the anlage of the developing eye in relatively early stages. Using standardized methods according to Lojda, activities of the following enzymes were proved in cryostat sections of the 9 and 10-week eye: ALP, ACP, ATP, TPP, alpha-GPDH and G6PDH. In 19-week eye moreover, positive reaction for DPP IV, ANE, CHE, ACHE was also detected, while G6PDH activity disappeared. In neither of the age categories SDH activity could be seen.

Animals↗
PubMed1992

Early prenatal development of the brush border enzymes in the embryonal intestine.

Standard methods were used for the study of the activity of brush border enzymes in the epithelium of the intestine of 45 human embryos aged from 4 to 22 weeks of the intrauterine life. Enzymes of the peptidase group (DPP IV, APM, APA, GGT, BBEP), of the phosphatase group (ALP, ACP, AMP, ATP), and of the disaccharidase group (saccharose, lactase, trehalase) were studied. In the embryonal developmental period (to week 8), the activity of proteases was mainly detected on the luminal surface of the primitive pseudostratified columnar epithelium of the intestine anlage. The highest activity was displayed by DPP IV. In the period from the 8th week, villi are formed from the duodenum up to the ileum. After week 9, differentiation of Lieberkühn crypts was observed. The activity of proteases was very high (DPP IV especially) in the differentiating microvillous zone of primitive enterocytes. Gradient of apex-base activity of the villus was maximal on the apex of villi. After week 12 of the intrauterine life, the activity of disaccharidases ALP and AMP occurs in the differentiating brush border, and a low activity of BBEP of the protease group is present.

Disaccharidases↗
PubMed1992

[Activity of gamma-glutamyl-transpeptidase in embryonic human organs].

The histochemical distribution of gamma-glutamyltranspeptidase (GGT) in organs of human embryos and fetuses was studied. In youngest embryos (4-7 weeks), a high GGT activity in the epithelium of the proximal part of embryonic intestine was recorded. Maximum of the activity was localised on membranes of luminal surface of primitive epithelium. High GGT activity in differentiating hepatocytes was also observed. In older fetuses (8-20 weeks) the activity of GGT gradually increases. In the epithelium of intestinal villi apex-basis gradient of the activity was recorded. The highest GGT activity in differentiating brusch border of the epithelium of proximale tubuli of fetal kidney was observed as well.

Cell Differentiation↗
PubMed1992

[Quantitative evaluation of capillaries in the myocardium of human embryos].

On cryostat sections of hearts of human embryos and fetuses aged 7 to 20 weeks, the length, density and internal surface (area) of capillaries were studied in surface unit of the ventricular myocardium using a semi-automatic apparatus MOP AM 03. The DPP IV and ALP-positive capillary segments were evaluated separately.

Alkaline Phosphatase↗
PubMed1992

[The effect of verapamil and nifedipine on the development of experimental atherosclerosis in rabbits].

The main objective of the study was to investigate the effect of the calcium antagonists Verapamil (2 mg.kg-1.day) and Nifedipine (1 mg.kg-1.day-1) on cholesterol (1%) induced atherosclerosis in rabbits. The drugs were administered s.c. twice daily over a period of 8 weeks. Blood lipid levels were determined three times during the experiment. After the experimental period the animals were killed and macroscopic changes on the aorta were recorded. For histochemical investigation samples were taken from the arch of the aorta and coronary artery. In cryostat sections lipids were determined by Sudan black B and Fett rot 7 B and the following enzymes were assayed: acid phosphatase, non-specific and acid esterase, acid beta-galactosidase, dipeptidyl peptidase I and II, and glucose-6-phosphate dehydrogenase. Following treatment with the calcium antagonists the levels of triacylglycerols and of total cholesterol were significantly increased in comparison with the control and diet groups. The ratio of HDL cholesterol to total cholesterol decreased in the treated animals. In lipoid plaques the activity of enzymes was enhanced in all experimental animals. There were however no qualitative differences in the composition of plaques between individual groups, which exhibited only quantitative differences. The number of migrating macrophages was increased only in the nifedipine treated animals. The extent of plaques was significantly decreased after nifedipine treatment, whereas verapamil failed to exert antiatherogenic effect. (Tab. 2, Fig. 4, Ref. 22.).

Animals↗