Immunologic detection of inactive enzyme molecules in the aging lens.
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Aging↗
Biomedical subjects
O Hockwin
Publications and source records attributed to O Hockwin.
[In vitro incubation of lenses. Model for testing substrate utilization of substances of the energy metabolism, demonstrated with bencyclane-hydrogen-fumarate (author's transl)].
When bovine lens homogenate was treated with bencyclane-hydrogen-fumarate, the carbohydrate metabolism was activated. This may chiefly be due to the fumarate part of the substance. A 24 H In vitro incubation of whole bovine lenses in TC-199 with and without bencyclane-hydrogen-fumarate did not show the above effect. On the model of former investigations by J.E. Harris et al. we modified the test procedure by selecting the medium and the time of incubation so that the endogenous carbohydrates of the lens were consumed, thus creating new metabolic balances. This metabolic condition allows investigations intended to activate metabolic processes and to restore the steady state of metabolic parameters. We investigated the effect of bencyclane-hydrogen-fumarate using the same method and found that given certain conditions the lens recovers when incubated for 2 h in TC-199 (containing 1 g glucose/1) with addition of a 10(-4) M solution of bencyclane-hydrogen-fumarate. The ATP-content of these lenses in particular gives proof of this result. As already observed in former investigations on homogenates, this effect is probably due to metabolization of the fumarate part of the bencyclane-hydrogen-fumarate by the citric acid cycle. The method used explains the differences observed when using lens homogenates or whole lenses under the same experimental conditions.
Adenine Nucleotides↗
[Changes in the content in reduced and oxydized glutathione in incubated bovine lenses (author's transl)].
Incubation of bovine lenses over a period of 24 h in Krebs-Ringer solution effects a decrease in the content of GSH. This decrease can be blocked by addition of 2 mM/1, each of glycine, glutamic acid, and cysteine. The content in GSSG is in no way influenced by incubation with or without addition of the three amino acids.
Animals↗
[Enzyme activities of bovine aqueous humour in dependence on age (author's transl)].
The specific activities of LDH, MDH and ALD of bovine aqueous humour show no significant changes in dependence on age. The protein content remains constant too. Determination of the enzyme activities of Sorbitoldehydrogenase and Pyruvatekinase was not successful due to disturbing activities of the crude aqueous. Substrate affinities (KM-value) of LDH, MDH and ALD are almost identical in aqueous, serum and lens of the bovine.
Aging↗
Experimental cataracts in rats due to tryptophan-free diet.
A tryptophan-free diet induces posterior subcapsular cataracts and reversible corneal opacities in young Wistar rats. Compared to the controls there is a significant decrease of body weight, lens fresh weight, and water-soluble lens protein. Protein separation by isoelectric focusing shows diminished alpha-, beta-, and gamma-crystallin fractions. If tryptophan is restored to the diet after 24 days, new clear lens fibers are laid down again, indicating that the mechanism of protein synthesis has not been permanently damaged by tryptophan-deficiency.
Animals↗
[The effect of fludilat on carbohydrate metabolism].
Fludilat (bencyclane-hydrogen-fumarate) increases the O2 consumption and CO2 production of a 10% bovine lens homogenate. An increase of the glucose substrate supply of the homogenate from 25 mM to 37 mM enlarges the above mentioned effects. Investigations on the content of ATP, ADP and AMP show that bencyclane is able to stabilize the physiologic distribution pattern of the three free adenine nucleotides. Changes of the distribution pattern pointing to disturbances of the energy metabolism could in part be normalized by incubation with the addition of bencyclane. This is not only true for lens homogenates but also for whole bovine lenses. Investigations with the enzymes fumarase and malatedehydrogenase indicate that the fumaric acid rest of bencyclane may serve as a substrate for these enzymes in the same way as fumarate. The Km-values found are identical.
Adenosine Diphosphate↗
The thin-layer isoelectric focusing of lactate dehydrogenase isoenzymes in rabbit lens parts and in intraocular tissues.
Lactate dehydrogenase (LDH) isoenzymes of rabbit lens and other intraocular tissues are separated by thin-layer isoelectric focusing and localized as discrete groups of multiple bands with defined isoelectric points after staining by the tetrazolium method. In the rabbit lens parts, the predominant isoenzymes are LDH-4 and LDH-5. The bands show microheterogeneity, are composed of 2-4 subcomponents, and the pattern shows a distribution of the liver type. The activity of the LDH-4 decreases and that of LDH-5 increases in an order given by the equator, anterior and posterior cortex, and nucleus. LDH-3 remains almost constant in all lens parts. LDH-4 is composed of two subcomponents, one of which, the most cathodic with higher isoelectric point, is almost absent in the lens nucleus. Of the LDH localized in the rabbit intraocular tissues, only the retina shows a pattern of five isoenzymes also of the liver type. In all intraocular tissues LDH-3, -4, and -5 are very prominent, show also microheterogeneity of their isoenzyme bands, and are each composed of 4-6 subcomponents. LDH-1 and -2 show only one isofocused component. Species specificity is shown of the LDH isoenzymes in the rabbit, mouse, dog, and calf lens.
Animals↗
Phenol oxidase activity of the iris and the ciliary body in rats.
Phenol oxidase activity of the iris and the ciliary body in normal young rats of three differently pigmented strains, Lewis (albino), E3 (light brown, hooded), and BDE (black, hooded), was studied using DL-Dopa. Applicability of the histochemical method was controlled with skin samples taken from the necks of the animals. In the pigmented strains, the appearance of newly formed pigment at the pigmented epithelium and stroma of the iris and ciliary body was observed. In the E3 animals, the reaction was slightly positive, while in the BDE rats it was more pronounced. No phenol oxidase activity was detected in the ocular structures of the albinotic rats.
Animals↗
Investigations of phosphofructokinase (PFK, EC 2.7.1.11) in bovine lenses in dependence on age, topographic distribution and water soluble protein fractions.
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Aging↗
[Determination of the KM-value of the fumarase (E.C. 4.2.1.2) with bencyclan-hydrogenfumarate as the substrate (author's transl)].
The Michaelis-Menten constant for fumarase (E.C. 4.2.1.2) has been determined by measuring the enzyme activity by the spectrophotometric method of Racker, which depends on the formation or disappearance of the double bond of fumaric acid. When using Na2-fumarate or bencyclan hydrogenfumarate (Fludilat), respectively, as a substrate, a KM-value of 1.3 X 10(-3) M was found for both substances. In a linked assay where the formation of NADH in the reaction of fumarate leads to malate leads to oxaloacetate was used as a parameter for the reaction rate, a KM-value of 1.35 X 10(-3) M was found.
Animals↗
[The immunological characterization and isoelectric focusing of water-soluble proteins in the lens related to aging (author's transl)].
Immunelectrophoresis, antigen/antibody crossed electrophoresis and isoelectric focusing are applied to characterize lens crystallins. Using isoelectric focusing alpha-, beta- and gamma-crystallins are determined in bovine lens nucleus and equator. The data obtained are compared with those of rat and human lenses. In these three species a disappearance of specific beta- and gamma-crystallin components is observed depending on age. Further, the presence of crystallins is demonstrated in cornea and vitreous body.
Aging↗
Action of bencyclane-hydrogen-fumarate on the carbohydrate metabolism of bovine lens homogenates.
1-Benzyl-1-(3-dimethylaminopropoxy)cycloheptane (bencyclane-hydrogen-fumarate; Fludilat) in a concentration of 10-2 M effects an increase in the O2 consumption and the formation of CO2 in a 10% bovine lens homogenate. This effect is even increased if the glucose-substrate supply is raised from 25 mM to 37 mM. Investigations on the concentrations at ATP, ADP and AMP show that bencyclane is able to stabilize the physiologic distribution pattern of the three free adenine nucleotides. Further, the observed changes in the distribution pattern indicated that the fumaric acid rest of bencyclane may serve as a substrate for this reaction in the same way as fumarate.
Adenosine Diphosphate↗
[Improved method of lens photograpy using retroillumination (author's transl].
Lens photography with a fundus camera using retroillumination is suited for long term follow-ups of senile cataract development. An improved method using a 9 grade colour standard is presented, which makes a comparative evaluation of the colour of the fundus reflex possible. A colour filter effect of the lens nucleus in nuclear sclerosis can thus be evaluated.
Aged↗
[Species differences in lens proteins after isoelectric focusing on polyacrylamide thin-layer plates].
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Animals↗
Enzymologic and histologic investigations in normal and pressure-ischemic retina of rabbits.
Histologic investigations together with histochemical and photometric measurements of enzyme activities were performed in retina of rabbits, whose blood supply had been totally interrupted for 1h. A retinal edema developed affecting the internal layers between the inner limiting membrane and the internal plexiform and ganglion cell layer. Although this edema was quite remarkable at the posterior pole of the eye, it diminished toward the periphery, disappearing near the ora serrata. The activities of the following enzymes were investigated: hexokinase, glucose 6-phosphate dehydrogenase, aldolase, glyceraldehydephosphate dehydrogenase, lactate dehydrogenase, malate dehydrogenase, succinate dehydrogenase, ATPase, and phosphorylase. The most striking finding was the total disappearance of phosphorylase activity under pressure ischemia. ATPase and aldolase showed a decreased activity in the ischemic retina, and malate dehydrogenase a slightly diminished one. Concerning the other enzymes, no significant differences between normal and ischemic retina were observed.
Animals↗
Age-related changes in the proteolytic enzymes of mammalian lens.
A longitudinal study has been conducted on three exopeptidases which include an esterase, leucine aminopeptidase, and a triglycinopeptidase and two endopeptidases, a neutral protease and a proteinase or catheptic activity in bovine lenses. The esterase and leucine aminopeptidase behave similarily showing increased activities with aging. Triglycinopeptidase has a somewhat lower order of magnitude when compared to the other exopeptidases. The neutral protease shows initially high activity early in the developmental life period, whereas, the proteinase or catheptic activity indicates a continuous increase with aging. Data whereas, the proteinase or catheptic activity indicates a continuous increase with aging. Data is also provided on enzymic activity in the different sections of the lens which include the combined anterior cortex and epithelium, lens nucleus, posterior cortex, and equatorial ring.
Aging↗
Glycogen concentration changes in retina, vitreous body and other eye tissues caused by disturbances of blood circulation.
The glycogen content in the individual eye tissues is strongly correlated to blood supply. Our investigations on the retina of bovines, which have not been fully evaluated, show that the time interval between interruption of blood supply and preparation of the retina is of special importance. Pressure ischemia affects a decrease in glycogen content in the retina and vitreous of rabbits, which is, however, less distinct in the vitreous. Decrease of glycogen with ischemia also takes place in the cornea and, to a lesser degree, in iris and choroid. In contrast, there is no decrease in the glycogen content of the lens. Changes in glycogen content of the rabbit retina after ligation of the A. carotis communis is less distinct than with pressure ischemia. In the vitreous, changes in glycogen content could not be observed. Values measured in both tissues of the ligated eye decrease with additional pressure ischemia.
Animals↗
Studies on the influence of leucomycine on the carbohydrate metabolism of the lens in vitro.
The influence of leucomycine (10(-5) M--5 X 10(-3) M) on enzyme activities, free adenine nucleotides, and some intermediates of glycolysis in bovine lenses has been investigated. After a 48 h incubation in TCM 199, 6 out of 9 enzymes activities tested were decreased. Concentrations of energy rich nucleotifes, glucose, fructose, and fructose-6-phosphate as well as those of fructose-1,6-diphosphate and lactate were also decreased, whereas adenine monophosphate was increased.
Adenosine Monophosphate↗