Biomedical subjects

A Veselá

Publications and source records attributed to A Veselá.

At least 19 recordsLinked to original sources

PubMed2006

[Reduction of the physiologic IOP value after instilation of the mixture of the 2 amino acid's (L-lysine and L-arginine) in timoptol--experiment on rabbit's].

UNLABELLED: To evaluate influence of mixture of the 2 amino acids (L-arginine-HCL and L-lysi-ne.2HCL.H2O) in the antiglaucomatic--beta-blocker Timoptol--on the physiologic intraocular pressure (IOP) in rabbits (experiment). METHODS: The mixture of 10% L-lysine.2HCL.H2O + 10% L-arginine.HCL in 0.5% Timoptol was instilled into the left conjunctival sac of the 5 adult rabbit's (female of the New Zealand White species) and the right eye was used as control. The IOP and pupilar diameter were measured before and in 5th, 15y th, 30th, 60th, 120th, 180th and 240th min. and 24 hours after the instillation. RESULTS: The experimental results proved that the non-selective beta-blocker Timoptol interacts at the same time with two amino acids. The mixture of 10% L-lysine.2HCL.H2O + 10% L-arginine.HCL in 0.5% Timoptol decreased the physiologic IOP in two phases. The first phase started from application up to 15th min. In this period parallel IOP decrease occurred also in control eye (with no significant difference). The second phase started in 30th min. after the instillation and lasted until the end of experiment. In this phase the control eye IOP remained linear after the initial over the baseline increase. The eye with instilled mixture showed significant IOP decrease (p < 0.01). Maximum difference between the two IOP's was measured in the 180th (7.3 mmHg; 35.4%). From this moment IOP slightly increased up to the 24th hour showing still significantly lower level--5.0 mmHg (24.3%) compared with the control (p < 0.01). CONCLUSIONS: Results proved that in the mixture of 10% L-lysine.2HCL.H2O + 10% L-argi-nine.HCL in 0,5% Timoptol a new substance, the "specific bioantiglaucomatic" is created by interaction. Compared with the substances alone, mixture of the 2 amino acids in the antiglaucomatic decreased the physiologic intraocular pressure (IOP) in rabbits (experiment) with high significance for 24 hours.

Adrenergic beta-Antagonists↗

PubMed2006

[The effect of glycine with timoptol on the rabbit IOP physiological values].

PURPOSE: the mixture of 10% L-glycine.HCl in 0.5% Timoptol, intensity and duration of effect on the physiological IOP is evaluated in this work. METHODS: Experiments were performed on 5 rabbits of the New Zealand White species. The mixture and its components were individually instilled into the left conjunctival sac. The right eye was used as control. RESULTS: after instillation of the 10% L-glycine.HCl and 0.5% Timoptol mixture the IOP showed significant decrease compared with the control eye during 24 hour evaluation. Maximal decrease for 33% (8.5 torr) was measured in 60th min., compared with the decrease for 30.5% (7.6 torr) in 120th and for 28% in 30th min. On the contrary, both substances alone--the 10% L-glycine.HC1 and 0.5% Timoptol decrease the physiological IOP values only no significantly compared with their mixture and the control eyes. The mean value of the pupilar diameter was 7.8 mm on both eyes. CONCLUSIONS: We assume that the decrease of the physiological IOP value is caused by a new metabolite--the "bioantiglaucomatic" created by interaction of glycine and Timoptol in vitro. The effect of this mixture on the decrease of the physiological IOP values is 8-times stronger compared with Timoptol and 4.3-times stronger compared with glycine. Application of such already prepared bioantiglaucomatic in the clinical practice can contribute to the more effective, safe and reliable therapeutic effect on the IOP in glaucomatic disease.

Adrenergic beta-Antagonists↗

PubMed2005

[IOP in rabbits after instillation of a mixture of the antiglaucomatic Cosopt and the aminoacid L-argininin HCL into the conjunctival sac].

OBJECTIVE: The article documents results of experiments focused to influence the physiological IOP values after application of the COSOPT eye drops (double combination of bbb-blocker and carbonic anhydrase inhibitor), aminoacid 10% L-arginin.HCl and their mixture in rabbits. METHODS: COSOPT followed by 10% L-arginin.HCl and mixture of 10% L-arginin.HCl with COSOPT was instilled weekly into the left conjunctival sac of 5 adult rabbits (females of the New Zealand White species). The IOP and pupilar diameter were measured in 5, 15, 30, 60, 120, 180, 240 min. and 24 hours after instillation. The right eye was used as control. RESULTS: The antiglaucomatic COSOPT no significantly decreased the rabbit IOP during 24 hours (mean value 1.85 %) in vivo. The aminoacid 10% L-arginin.HCl achieved significant decrease of the IOP: the mean value was 16.03% reaching maximum in 60th and 180th min. After instillation of the 10% L-arginin.HCl and COSOPT mixture in the IOP showed significant decrease with mean value of 9,64% (except values in 5th min. and 24th hour). Compared with control eye, the major decrease of the IOP was measured in 240th min. (mean value 17.98%). However even in 24 hours after instillation the IOP was not reaching the values of the control eye, shoving also the IOP decrease. CONCLUSION: We assume that in a double combination of antiglaucomatics in COSOPT a new substance was created. This substance interacted in vitro with the aminoacid 10% L-arginin.HCl resulting in a new "bio-antiglaucomatis" better penetrating into the target area. This new substance was responsible for more significant decrease after the mixture application compared with COSOPT alone. The presence of aminoacid can slow down the undesirable effect of the antiglaucomatics together with the possible neuroprotection.

Animals↗

PubMed2005

[The rabbit IOP and pupil values after application of aminoacid L-lysine and antiglaucomatic Timoptol mixture].

OBJECTIVE: In this article authors focused to influence the physiologic IOP values after application of the aminoacid 10% L-lysine.2HCl.2H2O in 0.5% Timoptol eye drops mixture in experiments. METHODS: 0.5% Timoptol, followed by 10% L-lysine.2HCl.2H2O and mixture of 10% L-lysine.2HCl.2H2O with 0.5% Timoptol was instilled weekly into the left conjunctival sac of 5 adult rabbits (females of the New Zealand White species). The IOP and pupilar diameter were measured in 5, 15, 30, 60, 120, 180 and 240 min. after instillation. The right eye was used as control. RESULTS: In experiments authors observed that: a) the aminoacid 10% L-lysine.2HCl.2H2O is without influence on the physiologic value of the IOP; b) 0.5% Timoptol compared with control eye nonsignificantly decreased the rabbit IOP; c) after instillation of 10% L-lysine.2HCl.2H2O and 0.5% Timoptol mixture the IOP showed decrease of the physiologic IOP in two periods. The initial non-significant period of the IOP decrease was measured after application up to the 60th min. The identical values were also in the control eye. However, the major decrease of the IOP compared with control eye was observed during the second period starting from 60th min. up to the end of experiments (to the 4th hour) after instillation of this mixture. The mean value of this significant decrease was 3.3 torrs of the physiologic IOP value showing regular and linear effectivity in the experimental eye. In the control eye the second period was without decrease of the IOP. CONCLUSIONS: The results demonstrate that the Timolol alone decreased the physiologic IOP no significantly, the aminoacid L-lysine.2HCl.2H2O is without influence on the physiologic value of the IOP. In experiments we confirmed that in a mixture of aminoacid L-lysine.2HCl.2H2O with antiglaucomatic 0.5% Timoptol a new substance was created, a new "bio-antiglaucomatic", responsible for more significant decrease of the physiologic IOP.

Animals↗

PubMed2005

[Changes of physiological intraocular pressure (IOP) in rabbits after administration of the amino acid lysine and the antiglaucoma drug latanoprost (Xalatan)].

PURPOSE: To show and underline specific character of influence of the mixture of 10% L-lysine.2HCl.2H2O in 0.005% latanoprost on physiological levels of IOP. METHODS: The mixture of 10% L-lysine.2HCl.2H2O in 0.005 % latanoprost (Xalatan), or separately 0.005 % latanoprost and 10% L-lysine.2HCl.2H2O respectively were in weekly intervals instilled into the conjunctival sac of the left eye of five rabbits (females of "New Zealand white" bred). The IOP levels and the size of the pupil were measured in minute 5, 15, 30, 60, 120, 180, and 240 after the instillation. The right eye was considered as a control. RESULTS: The amino acid L-lysine.2HCl.2H2O by itself did not influence the IOP or the size of the pupil; latanoprost until minute 30 lowered the IOP, in minute 55 exceeds the IOP the level of the control eye. Since minute 60 until 240, the IOP changed irregularly and insignificantly. The mixture of 10% solution of L-lysine.2HCl.2H2O in latanoprost 0.005% insignificantly lowered the IOP until min. 30, after rapid elevation in min. 50 exceeds the IOP of the control eye, and since min. 60, the IOP remains above the control eye's IOP with the same course of levels. SUMMARY: The amino acid L-lysine.2HCl.2H2O alone did not change the physiological IOP. Latanoprost 0.005% significantly lowered the IOP until min. 30. High level of interactive specificity as well as duration of influence of the mixture of respective amino acid with respective antiglaucomatic drug was established.

Animals↗

PubMed2004

[Intraocular pressure in rabbits after administration of 10% L-arginine HCl in 2% Trusopt].

In this contribution publish the observation that addition of 10% L-arginin.HCl to the 2% Trusopt eye drops intensifies activity of antiglaucomatics with an important reduction of the normal intraocular pressure (IOP) in rabbits New Zealand white namely from 15 up to 240 minutes, compared with application of both substance alone. Size of the pupil was not affected. Based on our experimental results we assume that this increasing activity of Trusopt mixture with amino acid L-arginin.HCl created a new metabolite. According to our observations this metabolite caused reduction of the humor aqueous production and together with the increased of the uveo-scleral outflow leads to the striking reduction of the IOP.

Animals↗

PubMed2004

[Comparison of the effectiveness of a mixture of 10% L-arginine and HCl combined with 0.5% Timoptol and with 2% Trusopt: and the individual components on intraocular pressure in an experiment on rabbits].

The presented experimental work is focused to examine effectivity of the amino acid 10% L-arginine x HCl mixture with antiglaucomatic--2% Trusopt (carbonic anhydrase inhibitor) and with 0.5% Timoptol (non-selective beta-blocker) and of the each single compound on intraocular pressure (IOP). In the group of 5 rabbits (New Zealander White) with physiological levels of IOP already the single amino acid L-arginine x HCl decreased the IOP (for 18.4% compared with 0.5% Timoptol and for 9.7% with 2% Trusopt). In case of mixture with the mentioned antiglaucomatics the L-arginine x HCl significantly increases their activity. The showed results indicate the presence of the free amino acids and their interaction with the adequate antiglaucomatic is required for correct action. Based on this interaction a new bio-active metabolite is created (possibly called as "bio-antiglaucomatic").

Animals↗

PubMed2004

[Reaction of the physiological IOP in rabbits after application of the latanoprost (Xalatan) and amino acid L-arginine HCl mixture].

Authors present results of series of experiments focused to influence the IOP by antiglaucomatics in rabbits (New Zealand White) with physiological IOP. Adding of the 10% amino acid L-arginine x HCl to the 0.005% Xalatan eye drops intensifies activity of antiglaucomatics resulting in 9.5% average reduction of the IOP in a four-hour experiments (with maximum in 15th min.--19.3%), compared with application of both substances alone. Size of the pupil was not affected. Based on our experimental results we assume that the increased activity of the 0.005% Xalatan mixture with 10% amino acid L-arginine x HCl created a new complete metabolite--"bio-antiglaucomaticum". According to our observations this metabolite caused increase of the uveo-scleral outflow leading to the striking reduction of the physiological IOP in rabbits.

Animals↗

PubMed2003

[A combination of timoptol and L-arginine HCl: a regulator of intraocular pressure in rabbits].

In our experimental study were determined changes IOP an pupil after application mixture of aminoacid 10% L-arginine.HCl in 0.5% Timoptol into the conjunctival sac of left eye of 5 healthy albinotic rabbits (the New-Zeland White species). The right eye was control. Our results proved that the mixture of 0.5% Timoptol with 10% L-arginine.HCl has significantly decreases IOP against the control eye during the whole experiment. The maximum of decrease IOP was reached in 60th min. (20.1%; 4 torr) and in 240th min. (10.7%; 2.1 torr). In comparison with effect of mixture of both compartments, the 10% L-arginine.HCl and 0.5% Timoptol applicated alone caused only non-significant IOP decrease. Papilar diameter in both eyes were identical (7-7.5 mm) during the whole experiment. We suggest that the interaction of L-arginine.HCl with Timoptol causes formation of the new metabolite which is, in fact already effective component; this new substance decreases production of aqueous humor of corpus ciliare and the IOP is decreased in this way in physiological conditions. Utilization of this knowledge in clinical conditions could contribute to better utilization and more harmless use of antiglaucomatics in glaucoma disease therapy. For that reason, more longtime studies should be performed to evaluate the effect of this new metabolite in local application.

Adrenergic beta-Antagonists↗

PubMed2002

[Physiologic significance of the interaction between timolol and free amino acids in eye structures].

The authors analyze the interaction of timolol maleate (Timoptol, Léciva Prague) with free amino acids with regard to the effect on intraocular pressure. The different colour reaction of an amino acid mixture with Timoptol, the decline of radioactivity of Na[I125] tyrosine with Timoptol and the formation of 8 radioactive fractions after addition of Timoptol to Na[I125] indicate: a) the specificity of interaction of each amino acid with Timoptol; b) suggest that between Timoptol and free amino acids a firm covalent bond develops with the concurrent development of a new biologically active metabolite. Evidence of the presence of a new metabolite is important from the aspect of understanding and more accurate definition of the action of Timoptol in tissue structures of the eye and thus also for possible effective treatment of glaucoma.

Adrenergic beta-Antagonists↗

PubMed2002

The role of carbon dioxide in free radical reactions of the organism.

Carbon dioxide interacts both with reactive nitrogen species and reactive oxygen species. In the presence of superoxide, NO reacts to form peroxynitrite that reacts with CO2 to give nitrosoperoxycarbonate. This compound rearranges to nitrocarbonate which is prone to further reactions. In an aqueous environment, the most probable reaction is hydrolysis producing carbonate and nitrate. Thus the net effect of CO2 is scavenging of peroxynitrite and prevention of nitration and oxidative damage. However, in a nonpolar environment of membranes, nitrocarbonate undergoes other reactions leading to nitration of proteins and oxidative damage. When NO reacts with oxygen in the absence of superoxide, a nitrating species N2O3 is formed. CO2 interacts with N2O3 to produce a nitrosyl compound that, under physiological pH, is hydrolyzed to nitrous and carbonic acid. In this way, CO2 also prevents nitration reactions. CO2 protects superoxide dismutase against oxidative damage induced by hydrogen peroxide. However, in this reaction carbonate radicals are formed which can propagate the oxidative damage. It was found that hypercapnia in vivo protects against the damaging effects of ischemia or hypoxia. Several mechanisms have been suggested to explain the protective role of CO2 in vivo. The most significant appears to be stabilization of the iron-transferrin complex which prevents the involvement of iron ions in the initiation of free radical reactions.

Animals↗

PubMed2001

[Change in the pH of aqueous humor after administration of anti-glaucoma agents in rabbits in vivo].

In this contribution the activity of antiglaucomatics--2% pilocarpine (pH 5.98), 0.5% timoptol (pH 6.58) and 0.005% xalatan (pH 6.83) is emphasized from the view of pH values and changes of the pH values of the rabbit aqueous humor in vitro after their application. The rabbit's aqueous humor pH is 7.59--similar to the human healthy eye (7.5-7.6). We observed that these antiglaucomatics decrease the aqueous humor pH to the acid levels in the following order: 2% pilocarpine > 0.5% timoptol > 0.005% xalatan. The most significant decrease was measured immediately after the application. From the view of speed of response and effectivity in time achieving the pH of the normal aqueous humor we constate the following order: 0.005% xalatan > 0.5% timoptol > 2% pilocarpine. The changes in pH of the aqueous humor after application of these antiglaucomatics are directly connect with their physiologic function in the eye. Moreover, they also point out the importance of the pH dependence of the antiglaucomatics applicated into the conjunctival sac in the treatment of the glaucoma disease.

Animals↗

PubMed2001

[The pH reaction in aqueous humor to antiglaucoma agents of various concentrations and pH levels].

The authors investigated the effect on pH of the aqueous humour in man (collected before surgery of senile cataract, where the pH of the aqueous humour was within the range of 6.80-7.46 (7.11 +/- 0.11), after administration of antiglaucomatic drugs with a different concentration and pH (0.005% Xalatan--pH 6.43, 0.5% Timoptol--pH 6.80, 1% Pilocarpine--pH 5.87, 2% Trusopt--pH 5.33) under conditions in vitro. All mentioned antiglaucomatic drugs immediately reduced the pH of the aqueous humour towards acid values in the following order: Trusopt-Xalatan-Pilocarpine-Timoptol. pH changes of aqueous humour after addition of Timoptol, Xalatan, Pilocarpine have the same course in time, and shift to alkaline pH values. The pH of aqueous humour after addition of Trusopt reached only during the 240th minute levels of the control aqueous humour. The pH values after all antiglaucomatic drugs did not change between 240 minutes and 24 hours. As regards the rate of activity and extent of effect in conjunction with the time when the pH of the control aqueous humour was attained the authors recorded the following order: Pilocarpine-Timoptol-Xalatan-Trusopt.

Aged↗

PubMed2000

[Additive effect of pilocarpine and Timoptol on pupillary diameter and intraocular pressure in healthy rabbits].

In the submitted paper experimental results are interpreted comparing the administration of two fundamental anti-glaucomatous drugs into the conjunctival sac of healthy rabbits of the Chinchilla strain. The authors administered 2% pilocarpine and 0.25% Timoptol (Timololi maleas, Léciva) alone, as combined consecutive administration and concurrent administration. The greatest effect on the width of the pupil and on IOP was exerted before 60 minutes by administration of pilocarpine, then Timoptol resp. And after 60 minutes the mixture of the two substances was most effective. This effect is explained by the additive action via substances produced by interaction (metabolites). Pilocarpine being a cholinergic substance promotes formation of the vitreous fluid and thus also an increased supply of free amino acids into ciliary body processes and the vitreous fluid. Timoptol then interacts with the increased amount of free amino acids and thus a greater and longer reduction of VOT occurs than after the action of newly formed cholinergic or newly formed adrenergic substances alone.

Adrenergic beta-Antagonists↗

PubMed1998

[Effect of pilocarpine in tissue structures of the anterior eye segment from the aspect of its interaction with free amino acids].

On the basis of the proofs of pilocarpine interaction with free amino acids, the mechanism of this alkaloid effect in the tissue structures of the eye anterior segment is explained. Differences of colour reactions of amino acids mixtures with pilocarpine, decrease of radioactivity of Na[I125]tyrosine mixture with pilocarpine, unsteadiness of radioactivity of Na[I125]protein A mixture with pilocarpine and rise of 16 radioactivity fractions after adding pilocarpine to Na[I125]proteins A a) show the specificity of interaction of each amino acid with pilocarpine; b) give evidence of a strong covalent bond between pilocarpine and free amino acid and give rise to new biologically active metabolite; c) show non-cholinergic pathway of pilocarpine effect; d) for ophthalmo-physiological practice it is said that with respect to the rate between pilocarpine quantity and concentration and free amino acid quantity and concentration requested therapeutical effect by lower pilocarpine dose in glaucoma disease treatment might be achieved. Thus free amino acids being reactants can be identified as mechanism by which pilocarpine becomes biologically active.

Anterior Eye Segment↗

PubMed1998

[Bioactivity and effect of a mixture of pilocarpine and lysine on the pupil and intraocular pressure in rabbits].

Based on experiments with rabbit eyes (strain New Zealand white) the authors submit evidence that the metabolite which is formed as a result of interaction of 2% pilocarpine and L-lysine 2 HCl.2H2O has a significantly greater and more rapid effect on the development of miosis than 2% pilocarpine alone. The amino acid lysine does not have a miotic effect. The authors explain the bioactivity of the new metabolite, its effect during the development of miosis and reduction of intraocular pressure. They emphasize a greater and more rapid bioactivity of the new metabolite as compared with pilocarpine. These results provide evidence that during treatment of primary glaucoma it is important to consider not only the effect on reduction of intraocular pressure but also physiological processes which develop in tissue structures after administration of different chemotherapeutic agents.

Animals↗

PubMed1990

Bioaccumulation of metals from nickel smelter waste in P and F1 generation of exposed animals. Part III. Morphological responses.

Inhalation exposure experiments were conducted on a group of female adult Chinchilla rabbits placed in a field biomonitoring station located downwind from dumped nickel refinery wastes. Their F1 generation offsprings were exposed prenatally and 6 weeks postnatally. After termination of exposure, both P and F1 generation rabbits were sacrificed, their organs removed and subjected to a histologic examination using light and electron microscopy techniques. The histological responses were most marked in P generation female rabbits, namely hypertrophy of the muscle layer of pulmonary artery walls and foci of atelactasis. Electron microscopic examinations of the myocardium of chamber-exposed rats revealed evidence of muscle fibre lesions at sites of intercalary discs and changes in mitochondrial structure as a result of accumulated Ni, Cr and/or other metals. Histologically remarkable was interstitial accumulation of an unidentified electron-dense crystalloid substance situated near blood capillaries and between myofibrils and collagenous fibres; this substance is believed to be a result of metal-protein interaction. The rats injected intravenously with a suspension of metal waste displayed mitochondrial lesions analogous to those observed after inhalation exposure, but no presence of the electron-dence substance could be noted. It is concluded that chronic exposure to metal waste may give rise to cardiovascular lesions.

Animals↗

PubMed1980

[Quantitative morphologic studies on the myocardium in early stages of ontogenesis and after application of various cardioactive agents].

The authors have morphometrically studied the differentiation of the myocardium in dynamic phases of the embryonic and postnatal development in chickens and Syrian Hamsters. Moreover, they investigated the action of the beta-adrenalytic substances Practolol and Trimepranol on ultrastructure of the cardiac muscle in adult animals. The volume of mitochondria in myocardial cells in 6-day old chicken embryos amounts to 5.65% of the total cell volume, in 12-day old embryos 14.35%, in 18-day old embryos 19.60%, in 1-day old chickens 23.24% which is nearly as much as in adult animals. The volume of myofibrils in 6-day old embryos is about 3.2%, in 12-day old embryos about 7.4%, in 18-day old embryos about 16.4% and in 1-day old chickens about 21.2%. The differences between individual groups are statistically significant. The dynamics of differentiation of the myocardium in Syrian Hamsters was studied in 5 phases, namely in 14-day old embryos and in postnatal phases on the 2nd, 5th, 14th and 21st days after birth. Most cells in 14-day old embryos are rather immature. Participation of the volume of mitochondria, myofibrils, equipment of mitochondria with cristae etc. considerably increase in postnatal phases. These findings suggest that the heart of mammals is rather immature at birth and will differentiate mainly in the postnatal developmental phases. Many morphometric findings, as regards the action of beta-adrenalytic drugs on the ultrastructure of the myocardium in adult rabbits, point to the fact that application of these substances will give rise to degenerative alterations in approximately 10% of myocardial cells. Theoretical explantation of these mechanisms is being discussed.

Animals↗