摘要:

Subcultured bovine corneal fibroblasts accumulated cyclic AMP intracellularly and in the culture media in response to incubation with 3-isobutyl-1-methylxanthine, isoproterenol, cholera toxin or forskolin. The duration of the intracellular cyclic AMP effect was rather short using isoproterenol (less than three hours) but cholera toxin and forskolin maintained cyclic AMP stimulations for 24 hours at greater than 3-fold and 27-fold over control, respectively. Agents which stimulated adenylate cyclase by different mechanisms or mimicked the action of cyclic AMP decreased collagen secretion by these cells. In general, the degree of inhibition of collagen production was consistent with the magnitude and duration of each drug's cyclic AMP response.

ISSN:0271-3683    

DOI:10.3109/02713688609020040

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

The effect of optical blur on the steady-state (6, 8, 10 Hz) counterphase pattern electroretinogram (PERG) was measured in three normal cynomolgus monkeys. Blur was induced using lenses of -8.00 to +12.00 diopters, and monocular PERGs were recorded at a viewing distance of 0.32 meters. A substantial decrease in PERG amplitude occurred with a 0.51 cpd grating when +4.00 diopters of blur or greater were used. PERG amplitude to a 1.25 cpd grating decreased with lenses greater than +2.00 diopters. Minus lenses caused a steep decline in PERG amplitude of both spatial frequency gratings. These results indicate that refractive state has a significant effect upon the PERG and should be carefully considered in electrophysiologic testing of the primate visual system.

ISSN:0271-3683    

DOI:10.3109/02713688609020041

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

The activities of five enzymes of glutathione metabolism were determined in lenses from cataract-resistant and cataract-prone (Emory) mouse variants at three different ages (5 weeks, 10 weeks and 6 months). The enzymes included those required for glutathione synthesis,γ-glutamylcysteine synthetase and glutathione synthetase, as well as glutathione-S-transferase, glutathione peroxidase and glutathione reductase. The differences in the activities of the five enzymes in the two mouse variants were not remarkable at any of the three ages. Activity of each enzyme was noted to be in excess of the preceding one in this integrated metabolic pathway, with the exception of glutathione reductase.γ-Glutamylcysteine synthetase appears to be the pacesetting enzyme of this metabolic scheme in the mouse lens. The activity of each enzyme was compared with that earlier reported for human, rabbit and dog lenses.

ISSN:0271-3683    

DOI:10.3109/02713688609020042

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

The activities of glutathione peroxidase, glutathione reductase and glutathione-S-transferase were determined in lenses from rhesus monkeys (Macaca mulatto) as a function of age. The ages ranged from 137 day old embryos to a 34 year old. Glutathione peroxidase activity (units/g lens) occurred at a very low level in lenses of fetuses and neonates, but increased dramatically with age, peaking in the adult of about 12 to 20 years of age and declining thereafter. Glutathione reductase activity (units/g lens) decreased throughout juvenile life, leveling off when adulthood was reached (at least 6 years of age). Glutathione-S-transferase activity showed considerable age-related variation. Calculations show that glutathione reductase is rate-limiting in the glutathione redox pathway.

ISSN:0271-3683    

DOI:10.3109/02713688609020043

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

We investigated the relationship of aqueous humor inflow rate and cyclic AMP concentrations to the spontaneous and dramatic changes in IOP associated with onset of darkness in our previously described model of circadian rhythm of intraocular pressure. After onset of darkness, rabbits entrained in an environment with a daily alternating cycle of 12 hours light and 12 hours darkness (12L:12D) showed an 85% increase in outflow pressure, a nearly 60% increase in aqueous inflow rate and an 80% increase in aqueous cAMP. Animals desynchronized by an unpredictable light cycle showed no increase in IOP or inflow rate when measured at the same time intervals as were the entrained animals. Thus, the IOP, aqueous inflow rate and aqueous cAMP are all seen to change in the same direction in a pharmacologically unperturbed rabbit eye. Previous pharmacological studies in rabbits have correlated an increase in cAMP with a decrease in IOP and aqueous inflow.

ISSN:0271-3683    

DOI:10.3109/02713688609020044

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

The interaction of ascorbate, hydrogen peroxide and oxygen has been examined in order to understand the equilibrium between these compounds that exists in the aqueous humor of the eye and their influence on function of the corneal endothelium. Ascorbate was found to promote corneal swelling when isolated corneas were perfused with a medium lacking glucose. This was found to be due to the rapid oxidation of ascorbate in the medium, yielding H2O2which is toxic to the endothelial cells. In the absence of oxygen, or if EDTA was added to the medium, no H2O2was produced from ascorbate, but ascorbate reacted with any pre-existing H2O2Oxidation of ascorbate in the aqueous humor is limited by the presence of glutathione (and, possibly, other compounds) and no significant increase in H2O2concentration occurs on standing in air. Nevertheless, the concentration of H2O2in the aqueous is directly dependent on the concentration of ascorbate secreted in the aqueous humor. Therefore, there must be a dynamic equilibrium in this fluid between ascorbate, H2O2and oxgyen, and it may be modulated by glutathione.Each of these substances is important in redox reactions, including free-radical production or scavenging. Consequently, when studying the effects on corneal or lenticular function of other agents which cause or relieve oxidant stress, it is critical that the modifying effects of ascorbate and H2O2, as they occur in vivo, be considered. A perfusion system is described which permits an approximation in vitro of stable concentrations of ascorbate, H2O2, SSH and O2similar to those found in the aqueous humor.

ISSN:0271-3683    

DOI:10.3109/02713688609020045

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

The diminished basal tear flow in aged individuals is associated with lymphocytic infiltrations and atrophy of the lacrimal ducts and acini. We have investigated the age-related physiological changes to sympathomimetic stimulation of lacrimal tissue from F344 rats to determine if the responses are uniformly diminished as would be expected by glandular atrophy. The quantitative and temporal pattern of protein and peroxidase secretion by lacrimal gland fragments from young (4 month) and aged (24 month) F344 male rats was examined in a perifusion system. Upon stimulation of tissue from young animals with 0.01 mM phenylephrine for 40 min, secretion above baseline levels of protein was 570.8μg/g tissue and of peroxidase was 45.2ΔA. min−1/g tissue. The response of the aged tissue to phenylephrine was not significantly different from that of the young tissue,β-adren-ergic stimulation by isoproterenol (0.01 mM) evoked only a modest secretion of protein and no consistently measurable peroxidase from young tissue. IBMX alone and in combination with isoproterenol (0.1 mM and 0.01 mM respectively) evoked a large secretion of protein, 1345.7μg/g tissue, and a modest secretion of peroxidase, 9.5ΔA.min−1/g tissue by young tissue. The aged tissue, upon stimulation with the combination of IBMX and isoproterenol, secreted significantly less protein and peroxidase than the young tissue. In separate experiments, the production of cAMP was measured. In young tissue, isoproterenol did not cause a measurable increase of intracellular cAMP. IBMX caused a 2–3 fold increase in cellular cAMP which was not increased further by addition of isoproterenol. Thus a lack of uniformity exists in the age-related changes of lacrimal protein secretion in response to sympathomimetic stimulation. If similar changes occur in human lacrimal gland, this suggests a complex etiology of lacrimal disfunction which includes glandular atrophy as well as selective changes in the responsiveness of the remaining tissue.

ISSN:0271-3683    

DOI:10.3109/02713688609020046

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

The immunochemical reactivities of theαA andαB subunits from bovineα-crystallin have been compared using 5 monoclonal antibodies and 2 polyvalent antisera. Each subunit bound the same maximum amount of antibody, regardless of its source, and each subunit was able to completely displaceα-crystallin from its antibodies. One monoclonal antibody (463–122) and mouse anti-αB polyclonal antiserum bound equally well to the two subunits; with the other monoclonal antibodies and an antiα-crystallin antiserum, the affinities for theαA chains were about 103fold higher than those for theαB chains.These observations indicate that theαA andαB subunits of bovineα-crystallin share several similar, but not necessarily identical, cross-reacting antigenic determinants. The reasons for the differences between these observations and those of other investigators are discussed.

ISSN:0271-3683    

DOI:10.3109/02713688609020047

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

ISSN:0271-3683    

DOI:10.3109/02713688609020048

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

Iontophoresis of 6-hydroxydopamine (6-HD) to the rabbit eye, followed by topical instillation of 2% epinephrine, induces ocular shedding of herpes simplex virus type 1 (HSV-1) reliably and with a high frequency in latently infected rabbits. Rabbit eyes inoculated with HSV-1 (McKrae strain) showed dendritic lesions indicative of acute HSV infection and subsequently shed virus spontaneously at least once during days 20 to 39 postinoculation (P.I.). Two iontophoretic conditions were employed. Group A (3 rabbits, 60.3 days P.I.) received iontophoresis of 1.0% 6-HD at 0.75 mAmp for 3 min. Group B (three rabbits, 67.3 days P.I.) received iontophoresis of 0.1% 6-HD at 0.5 mAmp for 8 min. Following iontophoresis, 2% epinephrine was instilled topically once on the day of iontophoresis and twice daily for four consecutive days. Tear film was collected on Dacron swabs and titered on African green monkey kidney cells by a plaque assay procedure. In group A, 100% (6/6) of the eyes shed virus, and the average duration of shedding was 4.0 days. The titers ranged from 2.0 to 7.7×104plaque-forming units (PFU) per eve. The highest daily average titer, 9.89×103PFU/eye, occurred on day 5 following iontophoresis. In Group B, 100% (6/6) of the eyes also shed virus, and the average duration of shedding was 5.3 days. The viral titer of the tear film ranged from 5.0 to 1.4×105PFU/eye. The highest daily average titer, 4.68×103PFU/eye, also occurred on day 5 following iontophoresis. There were no statistically significant differences in the kinetic and quantitative results of HSV-1 shedding between the two iontophoretic conditions. This is thefirstreport of thequantitationof HSV-1 in the tear film after iontophoresis of 6-HD is used to super-sensitize the eyes to adrenergic agents, followed by topical application of 2% epinephrine to induce viral shedding.

ISSN:0271-3683    

DOI:10.3109/02713688609020049

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor