摘要:

The low angle equatorial diffraction pattern from the human corneal stroma shows that the collagen fibrils have two preferred orientations: inferior-superior and medial-lateral. We have not observed this effect in any other animal species. This arrangement, which was found to be more pronounced in the posterior than in the anterior stroma, was maintained until the last 1 to 2 millimetres before the limbus at which point uniaxial orientation was observed along the circumference. Our interpretation of this result is that most collagen fibrils wrap around the circumference of the cornea and relatively few continue radially into the limbus where uniformity of collagen fibril diameters is lost.

ISSN:0271-3683    

DOI:10.3109/02713688709034853

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

The present study was aimed to demonstrate that cytochrome P-450 was induced by drug administration in particular tissues in the eye. Phenobarbital was used as an inducer. We showed immunohistochemically that cytochrome P-450 was induced in the cornea, conjunctiva and ciliary epithelium of rabbits after four days of intraperitoneal administration of phenobarbital at a dose of 80 mg per kg per day. We did not detect significant immunofluorescence in other ocular tissues. Prolonged administration caused degeneration of the ciliary epithelium, but no pathological change was seen in other ocular tissues. In this case, immunofluorescence was not detected in the ciliary epithelium but in the cornea, conjunctiva and lens.

ISSN:0271-3683    

DOI:10.3109/02713688709034854

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

Values of the diffusion coefficient into the anterior chamber and the“blood aqueous barrier permeability as a function of age were determined by fluorophotometry in 58 healthy volunteers. The diffusion coefficient was calculated from aqueous fluorescein concentration and the time integral of non-protein bound fluorescein concentration in plasma. Blood-aqueous barrier permeability was calculated using diffusion coefficient values, the area of fluorescein inflow into the anterior chamber and anterior chamber volume.Values for diffusion coefficient as well as permeability were found to be independent of age between 13 y and 72 y (lin. corr. coeff. 0.2, p = 0.11) mean values were U.T.10 min + 1.5. 10−4SD and 15.4 nm/s±; 4.8 SD, respectively. The difference between permeability values calculated from fluorophotometric scans at 30, 55 and 65 mins. after fluorescein injection was less than 5% and the 7 months reproducibility was within 15%. There was no significant correlation between simultaneously measured values of blood-retinal and blood-aqueous barrier permeability (lin. corr. coeff. 0.13, p=0.4).

ISSN:0271-3683    

DOI:10.3109/02713688709034855

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

Intravitreal injection of 5μg ofShigellaendotoxin, in the rabbit eye, induced an acute inflammatory response which was characterised by conjunctival hyperaemia, limbal and ciliary vascular injection, iritis, aqueous flare, miosis and reduction in intraocular pressure. Irisciliary body tissues, from normal and inflamed eyes, were fractionated into subcellular enriched fractions and the activities and distribution of selected enzymes were estimated. Alkaline phosphatase, a plasma membrane-bound enzyme, showed an increase in activity, whereas succinate dehydrogenase and Mn-Superoxide dismutase, both mitochondrial-bound enzymes, exhibited decreased activities. Lysosomal acid phosphatase displayed an increase in free activity and retention of latent activity inside the organelle. NO alteration in free activity was shown by acid cathepsin. The cholinesterases did not exhibit any changes in activities nor did the cytosolic enzymes Cu/Zn-superoxide dismutase and lactate dehydrogenase. The decreased activity of the respiratory mitochondrial enzyme succinate dehydrogenase may contribute to the reduction in intraocular pressure, and the ability of the lysosomal organelles to retain their hydrolytic enzymes, ensures recovery of the cell from acute inflammatory attack.

ISSN:0271-3683    

DOI:10.3109/02713688709034856

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

Mediated transport of dehydro-L-ascorbic acid (DAS) occurs in the mammalian ocular lens. At physiological pH, there is negligible cellular uptake of reduced L-ascorbate (AS). In the calf, inhibition by analogues and by cytochalasin B, and saturability with increasing concentration provide evidence of a transport-system for DAS, apparently by facilitated diffusion, since entry was independent of external Na+. The lenticular transporter for DAS evidently is interrelated with that for hexoses, as determined by kinetic studies and inhibition by analogues. Although the two ligands bind initially to separate sites, they probably permeate cellular membranes of this tissue via a common channel.Investigation of AS in the calf's lens over the range, pH 5.0–7.4, showed that uptake increased with increasing acidity in contrast to DAS and D-glucose, whose uptake decreased. This behavior of AS was attributed to back-titration of its enolic hydroxyl group to give the un-ionized moiety, which penetrated as readily as DAS under comparable conditions, and apparently undergoes mediated transport.

ISSN:0271-3683    

DOI:10.3109/02713688709034857

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

The differential distribution of albumin and IgG within various intraocular tissues suggests that charge rather than serum concentration plays an important role in regulating the distribution of certain molecules within the eye. The presence of anionic sites within the uveal tract indirectly regulates the localization and binding of cationic IgG by electrostatic interactions. Our studies indicate that circulating cationic IgG antibodies of pI 9.0–10.0 readily traverse the fenestrated capillaries in the ciliary body /processes and choriocapillaris and bind within vessel walls and stromal anionic regions and Bruch's membrane. Since there is normally no IgG produced within the non-inflamed, quiescent eye, this regulatory mechanism is potentially important in mediating immunologic protection within the uvea.

ISSN:0271-3683    

DOI:10.3109/02713688709034858

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

Purified human retinal S-antigen (S-ag) was used to investigate the occurrence of humoral and cellular autoimmune reactions against S-ag in uveitis patients. With a sensitive ELISA method anti-S-ag antibodies could be detected in the sera of 28% of the uveitis patients. No difference was found between patients with posterior or pan-uveitis (31 out of 117 positive) and patients with anterior or intermediate uveitis (16 out of 52 positive). Similar frequencies and levels of anti-S-ag autoantibodies were also found among healthy controls (6/20) and patients who had undergone cataract surgery (6/17). Immunoblotting with purified S-ag and with whole human retinal extract confirmed the presence of anti-S-ag antibodies in uveitis and control sera. Moreover, antibodies against various other retinal proteins could also be demonstrated in patients and controls, without being particularly enhanced in uveitis.The cellular immune responsiveness was tested by measuring the production of migration inhibitory factor (MIF) during overnight culture of peripheral mononuclear cells with the antigen. None of 18 healthy controls responded, whereas 17 positive reactions were observed in the group of 44 uveitis patients. The highest frequencies were found in patients with posterior (5/12) or pan-(7/12) uveitis, while of the responders with anterior (2/8) or intermediate (3/12) uveitis, three had disorders affecting the retina. Thus, cellular autoimmune responsiveness to S-ag is apparently associated with posterior and pan-uveitis, and might also occur in non-uveitic retinal disorders, whereas the occurrence of anti-S-ag antibodies is probably not at all pathognomic for uveitis.

ISSN:0271-3683    

DOI:10.3109/02713688709034859

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

This study probed the influence of antigenic exposure on the immunological response of the lacrimal gland. We utilized the germfree rat as a model system to monitor tissue and tear immunoglobulin changes following transfer of these animals into an antigen-laden, conventional environment. The number of IgA-and IgM-containing cells in the lacrimal glands of germfree rats was 5 to 8 fold less than that of conventional controls. This reduced immunological expression in germfree animals also extended to tear IgA levels, which were significantly decreased. No effect of germfree conditions was found on the tear content of secretory component (SC). Transfer of rats from a germfree to a conventional environment resulted in a significant increase in the number of IgA-and IgM-containing cells in the lacrimal gland. By four weeks after‘conventionalization’, the number of Ig-containing cells in lacrimal tissue was similar in both ex-germfree and conventional rats. In addition,‘conventionalization’led to a significant increase in the tear content of IgA: within four weeks following exposure to a conventional environment, tear IgA levels in ex-germfree rats were equivalent to those of age-matched, conventional controls. Overall, our results demonstrate that the secretory immune system of the lacrimal gland reacts to antigenic challenge with an increased immunological response.

ISSN:0271-3683    

DOI:10.3109/02713688709034860

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

Intraocular injection of highly purified human interleukin 1 into the anterior chamber of the rabbit eye resulted in the accumulation of inflammatory cells. Peak cellular infiltration occurred at 4hr and cells were still present at 24h. Examination of ocular blood vessels in IL-1 - injected eyes revealed no abnormalities. IL-1 had no effect on the protein content of the aqueous humour confirming that this monokine has no direct action on the blood-aqueous barrier. Comparison of the potency of IL-1 as a chemoattractant with the 5-lipoxygenase product, leukotriene B4demonstrated that the former agent was more active by several orders of magnitude.

ISSN:0271-3683    

DOI:10.3109/02713688709034861

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor

摘要:

Administration of vasoactive intestinal polypeptide (VIP) into the rabbit third ventricle via a permanently placed cannula resulted in a dose-dependent increase in intraocular pressure (IOP). 10P was elevated 5.2 mmHg 30 minutes after VIP (10μg/100μl) administration. Tonographic outflow facility was not altered by VIP. Thirty minutes after VIP injection into the third ventricle, aqueous humor flow estimated using the Goldmann equation was increased 36% over baseline levels. Intravenous administration of a 10 ug dose of VIP did not alter IOP. Systemic blood pressure was unaltered after third ventricle VIP. Systemic pretreatment with the cholinergic antagonist atropine blocked the VIP-induced elevation in IOP. Topical atropine pretreatment had no effect suggesting a central cholinergic mechanism for the VIP-induced increase in IOP. Physiological antagonism of the VIP response was observed after systemic pretreatment with propranolol, phentolamine, or acetazolamide.Body temperature (BT) was significantly elevated in a dose-dependent manner following central VIP administration. Indomethacin pretreatment which had no effect on the IOP response, blocked the VIP temperature response.

ISSN:0271-3683    

DOI:10.3109/02713688709034862

出版商:Taylor&Francis    

年代:1987

数据来源: Taylor