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Biomedical subjects

J Cejková

Publications and source records attributed to J Cejková.

15 recordsLinked to original sources
PubMed1978

Biochemical and histochemical response to a complete epithelial denudation of the rabbit cornea. Alkaline and acid phosphatase.

Activities of alkaline and acid phosphates were investigated in rabbit corneas after a complete epithelial denudation in vivo (limbus to limbus). Dynamics of enzymatic changes during corneal healing were followed quantitatively in homogenates of regenerated epithelium and stroma (denuded cornea) and in cryostate frozen sections on days 1, 4, 7, 14, and 28. Biochemical and histochemical findings at these times showed a different response in each enzyme. Acid phosphatase displayed a gradual increase of activity in epithelium as well as in stroma; on day 28 after injury its content was normal. In contrast, alkaline phosphatase showed delayed activity during the repair process, and even a month after de-epithelization was still subnormal, particularly in superficial layers of epithelium.

Acid Phosphatase↗
PubMed1977

A study on alkaline phosphatase in cornea of various animals with special regard to keratocytes.

The distribution of alkaline phosphatase was investigated in corneas of various animals by means of histochemical and biochemical methods. Special attention was paid to keratocytes that proved to be positive when a proper substrate and technique were used even if the activity differed according to animal species. Naphthol-AS-MX-phosphatate with Variamine-Blue-RT salt in the simultaneous azocoupling method was the most sensitive substrate; less suitable were naphthol-AS-phosphate, and particularly l-naphthyl-phosphate with Fast-Blue-BB-salt in the same method. Keratocytes were completely negative with beta-glycerophosphate in the Gomori technique. Contrary to keratocytes, epithelial and endothelial cells were without substrate predilection. The results of both approaches showed a wide inter-species variability. The overall activity of alkaline phosphatase detected histochemically and its activity in the unsedimentable fraction of whole corneas determined biochemically was in good agreement. The highest activity was found in the calf cornea; enzyme levels decreased gradually in the bovine, rabbit, dog, sheep, and pig cornea.

Alkaline Phosphatase↗
PubMed1976

Uneven distribution of alkaline phosphatase in individual layers of rabbit and ox cornea. Histochemical and biochemical study.

In the rabbit and bovine cornea the activity of alkaline phosphatase using histochemical as well as biochemical methods was investigated. Biochemically the enzyme activity was studied in separated corneal layers. In the histochemical investigation the best results were obtained in cryostat sections using the azocoupling method with naphthol AS-MX phosphate and Variamine Blue RT Salt. The enzyme activity was found not only in the epithelium and endothelium (as was described previously) but even in keratocytes. The mutual relation of activities in the epithelium and in keratocytes differed in both species. The overall activity found by histochemical methods is in good agreement with the biochemical determination of alkaline phosphatase (p-nitrophenyl phosphate as the substrate). Besides the histochemical approach shows an uneven distribution of alkaline phosphatase activity in individual cells which cannot be assessed by the biochemical determination.

Alkaline Phosphatase↗
PubMed1975

Distribution of acid phosphatase, beta-glucuronidase, n-acetyl-beta-d-glucosaminidase and beta-galactosidase in cornea of albino rabbit.

Activities of acid phosphatase, beta-glucuronidase, N-acethyl-beta-D-glucosaminidase and acid beta-galactosidase were investigated histochemically in rabbit corneas. Frozen sections after block fixation in cold 4% formaldehyde with 1% CaCl2 followed by washing in cold physiological saline as well as cold microtome sections of corneas quenched in petroleter chilled with acetone-dry ice mixture, transferred to nonprecooled slides or semipermeable membranes were used. Standard aqueous media were employed in the case of free-floating frozen sections of fixed corneas as well as of cold mictrotome sections (postfixed in cold 4% formaldehyde). Agar media were used in connection with the technic of semipermeable membranes. Gomori method (in the case of acid phosphatase), simultaneous azocoupling methods (substrates derivated of naphthol-AS-BI with hexazonium-p-rosanilin) in the case of acid phosphatase, beta-glucuronidase and N-acetyl-beta-D-glucosaminidase and the indigogenic method in the case of acid beta-galactosidase were applied. Enzyme activities in sections of fixed corneas were minimal in comparison with those in cold microtome sections of unfixed material revealed particularly with the technic of semipermeable membranes which is to be preferred. This technic is recommended in studies concerned with lysosomal enzymes in the cornea, particularly in keratocytes. All enzymes investigated were present in corneal epithelium, keratocytes and endothelium. Acid phosphatase displayed the highest activity followed by beta-glucuronidase and acetyl-beta-D-glucosaminidase. The activity of beta-galactosidase was the lowest. For the demonstration of activities in keratocytes sections parallel to the surface are very suitable. In these sections enzyme activities were demonstrated in small granules (apparently lysosomes) present in the central part of their cytoplasm as well as in projections. Diffuse staining was also seen, being the highest in the case of acid phosphatase.

Acetylglucosaminidase↗
PubMed1975

Alkali burns of the rabbit cornea. II. A histochemical study of glycosaminoglycans.

In alkali burned rabbit cornea the stainability of glycosaminoglycans in cold microtome setions was investigated. Staining by Alcian blue in 3% acetic acid, Alcian blue in various MgCl2 concentration and toluidine blue (pH 4.5) was employed. From the 1st to the 4th experimental day the intensity of reactions was decreased. This is most probably due to an increased hydration of the corneal stroma. On the 7th day hydration was markedly suppressed and reached nearly the normal level. In this time interval a decreased stainability of glycosaminoglycans was seen accompanied by a complete loss of staining in the marginal zone. On the 14th day the stainability in the traumatized area began to restore and in the marginal zone appeared. On the 32nd day the staining intensity of both areas was normalised, however when lower concentrations of MgCl2 were used; in the presence of higher concentrations of MgCl2 the decreased staining intensity persisted and points to a lower sulfatation of glycosaminoglycans. This was particularly remarkable in the area bordering the injured zone. This decrease runs parallel to the increased activities of acid glycosidases (especially of acid beta-galactosidase) which were reported previously.

Alcian Blue↗
PubMed1975

Incipient atrophy of cornea. Experimental study.

The essence of the process in which the corneal tissue disappears in atrophy of the eye has not yet been studied. The authors of this investigation studied the changes in cornea as they developed after a gross perforating injury to the eye in rabbit. They found that the diameter of the cornea had grown smaller by 2 mm and its radius by 0.5 mm. The tensile strength of the cornea had decreased and hydration increased. Histologically there were but little changes and histochemically a decreased amount of acid mucopolysaccharides was ascertained in the corneal stroma. Incorporation of radioactive sulphate (Na2-35SO4) in vivo disclosed decreased biosynthesis of glycosaminoglycans. Clinically, even though the eye ball atrophied, complete atrophy with flattening and complete diminution, as in the human eye, never developed. The question arises whether the six-months period was sufficient for rabbit cornea to develop clinically similar atrophy as in human cornea or whether the clinical features are principally different in the two species. Foci of ossification, as found in atrophic eye balls, which are known to develop after a long time, would be evidence of the second alternative.

Animals↗