摘要:

We investigated the synthesis and degradation of collagen In lacerated rabbit corneas. The rate of collagen synthesis was measured by the incorporation and hydroxylation of [14C]proline up to 5 weeks after a penetrating laceration. Our results indicate that protein and collagen synthesis is initially reduced during the 24 h period after laceration and then Increases in two phases. A moderate increase in protein and collagen synthesis occurs up to day 5 after laceration. Synthesis then decreases to a low level through the 10th day after injury. A second wave of increase in protein and collagen synthesis takes place reaching a new peak of approximately twice the activity as found in control corneas after 5 weeks of healing. Afterwards, the rate of protein and collagen synthesis declines and reaches the basal level after 7 weeks of healing. In a separate set of experiments, rabbit corneas were lacerated and allowed to heal for one or three weeks at which point 100µ;Ci of [14C]proline was injected into each anterior chamber. The corneas were excised 1 to 17 days later and subjected to collagen analysis. Our data indicates that the degradation of collagen synthesized by the cornea 1 week after laceration followed biphasic kinetics. In the first phase, the half-life of newly-synthesized collagen is 20 days, whereas it is approximately 4 days in the second phase. It is of particular interest that the accelerated degradation of the newly-synthesized [14C]collagen is concomitant with the increased rate of collagen synthesis during the wound healing process. The degradation of collagen synthesized 3 weeks after injury was slower and followed monophasic kinetics having a half-life of 14 days. The degradation of non—collagenous14C-proteins follow a monophasic kinetics having a half-life of 6-7 days. Polyacrylamide gel electrophoresis of newly-synthesized collagen indicated that the collagen(I) and collagen(V) were the main collagenous components synthesized by the lacerated corneas.

ISSN:0271-3683    

DOI:10.3109/02713688609015118

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

We adapted a previously described procedure to quantitate collagen in corneal tissue sections prepared from paraffin-embedded samples. The method entailed staining the deparaffinized tissue sections with Sirius red, eluting the bound dye with NaOH-methanol, and estimating the color in a spectrophotometer as an indication of the collagen content. This simple, rapid and reproducible method is comparable to biochemical assays and can be applied to study various corneal specimens readily available from eye pathology laboratories.We examined corneal sections from patients with aphakic bullous keratopathy, pseudophakic bullous keratopathy, Fuchs' dystrophy and lattice corneal dystrophy with this method. No significant difference in collagen staining was found between these pathologic specimens and normal control tissues. Biochemical assays also confirmed these findings. Sections from patients with macular and granular corneal dystrophies showed reduced staining suggesting a possible alteration in collagen content. This possibility, however, was not supported by data from biochemical analysis.

ISSN:0271-3683    

DOI:10.3109/02713688609015119

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

The influence of unilateral ocular instillation of B-HT 920 (50µg) on regional ocular, cerebral and peripheral blood flows was investigated with the labelled microsphere method in conscious and anaesthetized albino rabbits. In urethane-anaesthetized rabbits the intraocular pressure (IOP) fell during 1 hr following topical B-HT 920 whereas no changes in regional blood flows were observed. Only in conscious rabbits was a decrease in regional blood flows found. B-HT 920 caused a short-term reduction in choroidal blood flow by about 20%.Transient vasoconstrictor effects, due to systemic absorption, were also seen in some extraocular tissues. Concomitantly, B-HT 920 reduced the total cerebral blood flow (CBF) by 23%. In the grey matter and hypothalamic region the decrease in flow was about 20%, while in the hippocampal region, thalamic region, collides and pons-mesencephalon it was about 10%.In experiments with direct blood flow determination from an opened vortex vein, there was no consistent change of uveal vascular resistance, while IOP and mean arterial pressure (MAP) fell dose-dependently following cumulative intravenously administered bolus doses (10 and 50µg/kg) of B-HT 920. Unilateral loss of the mediated sympathetic tone seemed to increase the ocular responses to B-HT 920, unmasking a vasoconstrictor effect. Additional systemic pretreatment with the selective blocking agents rauwolscine and sulpiride suggests that B-HT 920 produces its ocular hypotensive effect, predominantly by acting on dopamine (DA2) receptors in the eye rather than onα2-adrenoceptors, and its ocular vasoconstrictor effects via both receptor types.

ISSN:0271-3683    

DOI:10.3109/02713688609015120

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

A-scan ultrasound was used to measure the position of the gas-fluid interface in eyes following vitrectony and gas internal tamponade. Using 20 eyes of 19 patients it was found that in most instances the gas-fluid interface could be measured to within 0.5mm. The procedure was simple to perform and was well tolerated by the patients. This appears a useful way of monitoring changes in intraocular gas volome.

ISSN:0271-3683    

DOI:10.3109/02713688609015121

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

Different forms of experimental autoimmune uveitis (EAU) can be produced by varying protocols to present different autoantigens to several species of experimental animal. We have studied the clinical, histological and serological responses of rabbits to footpad injection of various fractions of retina extract. Rabbits injected with retina extract or S antigen developed posterior uveitis. However, rabbits injected with retina extract, also developed an anterior uveitis and pinealitis not seen in rabbits receiving S antigen. The Serological response of rabbits to retina extract was different than that to purified S antigen. Antisera of rabbits receiving retina extract reacted with rabbit retina and pineal gland as well as with guinea pig retina but not with guinea pig pineal gland. In contrast anti-S antigen sera reacted with rabbit retina and guinea pig retina and pineal gland but not with rabbit pineal gland. Gel filtration chromatography of the ammonium sulfate supernate of retina extract was used to differentiate the antigens with which these two sera reacted. An analysis of these experiments gives preliminary evidence of an autoantigen(s) of rabbit retina and pineal gland that is not S antigen. The existence of multiple autoantigens common to retina and pineal gland in various species is significant in that it further underscores the relationship of these tissues. Furthermore, it is not unrealistic to expect more than one autoantigen of retina or uvea to be involved in autoimmune uveitis.

ISSN:0271-3683    

DOI:10.3109/02713688609015122

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

Human choroidal melanocytes were isolated from eye bank tissue and cultured in vitro with 10ng/ml cholera toxin and 10ng/ml phorbol myristate acetate. These growth factors induced rapid proliferation of spindle-type melanocytes. Similar results were obtained using 10mM putrescine. Phenotypic analysis of these cells by immunoperoxidase staining with anti-HLA-DR monoclonal antibodies revealed 40-70% positive cells. HLA-DR positive melanocytes were isolated and purified from the HLA-DR negative population by resetting with protein-A coupled sheep erythrocytes followed by differential centrifugation. Ultrastructural analysis of choroidal melanocytes revealed evidence of premelanosomes and melanosomes. Choroidal melanocytes in tissue culture are important experimental controls for the study of the cell biology of choroidal melanoma.

ISSN:0271-3683    

DOI:10.3109/02713688609015123

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

The amount of 9-β-D-arabinofuranosyladenine (ARA-A) and 9-β-D-arabinofuranosylhypoxanthine (ARA-Hx) present in ocular tissues of rabbits was determined following therapy with ARA-A alone and when ARA-A was used in combination with 2′-deoxy-coformycin (dCF). Topical therapy was initiated three days after infection of the corneas of rabbits with herpes simplex virus type 1. Ocular tissues were harvested after two days of therapy and analyzed by high performance liquid chromatography. Combination topical therapy with ARA-A and dCF significantly increased the tissue content of ARA-A in all tissues examined except retina, as compared to therapy with ARA-A alone. The ARA-A content of the two ocular tissues most often subject to acute herpes infections, the conjunctiva and cornea, was increased from 29.9±11.7 to 144.0±53.3 pmoles/mg dry weight and from 15.4±6.1 to 231.8±30.8 pmoles/mg dry weight, respectively. Except for the aqueous humor, the total arabinoside content of each tissue was not significantly altered by combination therapy, merely the ratio of ARA-A to ARA-Hx was changed. These studies demonstrate that combination topical therapy with ARA-A and an inhibitor of ARA-A catabolism, dCF, can effectively result in elevated amounts of ARA-A in ocular tissues.

ISSN:0271-3683    

DOI:10.3109/02713688609015124

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

It has been hypothesized that there are differences between membrane-associated gly-coconjugates of wounded (migrating) epithelium and those of nonwounded (stationary) epithelium. To test this hypothesis, wheat germ agglutinin-ferritin (WGA-Fe) and concanavalin A-ferritin (Con A-Fe) binding to apical membranes of wounded and nonwounded rabbit corneal epithelia were compared. Epithelial abrasions of the superior half of the cornea were allowed to heal in vivo/ for six hours. Fixed corneas were then Incubated with lectin-ferritin and prepared for electron microscopy. Measurements (ferritin particles per linear um of membrane) of WGA-Fe Indicated that binding to leading cells (40.7 particles/um), to areas 20 to 35 cells behind the leading edge (46.5 particles/um) and to nonwounded epithelium (45.1 particles/um) from contra lateral eyes were not significantly different. A competitive inhibitor of WGA, 0.2M N-acetylglucosamine, however, blocked 94 percent of WGA binding on leading cells (2.3 particles/um), while binding persisted In areas behind the leading edge (39.5 particles/um) and on nonwounded epithelium (43.6 particles/um). This indicates that leading cell surfaces have a weak affinity for WGA. Unlike WGA, Con A showed a distinct preference for leading-edge cells (33.9 particles/um) compared to nonwounded epithelium (9 particles/um). In areas 20-35 cells behind the leading edge. Con A binding was Intermediate to these two extremes. This differential in Con A binding to the cells In wounded epithelium compared to nonwounded epithelium suggests that wounding Induces a change In the composition of membrane-associated gly-coconjugates. Evidence that Con A was binding primarily to simple of igosaccharides In each test area was obtained when endoglycosidase H, an enzyme which hydrolyzes high mannose glycoconjugates at their di-N-acetylchitobiose core, reduced binding by at least 60% In each test area. Taken together these data support the contention that there are differences In lectin receptor sites on wounded and nonwounded corneal epithelia.

ISSN:0271-3683    

DOI:10.3109/02713688609015125

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

Fluorescence quenching using acrylamide and iodide quenchers has been used to investigate the microenvironments of tryptophan residues in bovineα-,β-, andγ-crystallin fractions. Acrylamide quenching is very senstive to the degree of tryptophan accessibility to the solvent containing the acrylamide. Since acrylamide is able to diffuse into the interior of the protein, accessibility to acrylamide may result from Trp residues lying at the surface of the protein or from the existence of channels leading to the interior of the protein. Iodide ion is hydrated and is limited by its large size and charge to quenching of tryptophan residues lying at or near the surface of proteins. Tryptophan residues in the lens crystallin fractions were found to be highly accessible to acrylamide, yet the rate of quenching by acrylamide was very low, indicating that the tryptophan residues of the lens crystallin fractions occupy predominately hydrophobic environments. The high accessibility to acrylamide likely results from diffusion of acrylamide into the interior of the protein. Accessibility to iodide was much lower, as was the rate of quenching by iodide, adding support to the conclusions from acrylamide quenching.

ISSN:0271-3683    

DOI:10.3109/02713688609015126

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor

摘要:

The relationship between the pressure applied to the enucleated human eye using the Honan Intraocular Pressure Reducer (HIPR) and the peak intraocular pressure as a function of initial intraocular pressure has been examined. The peak intraocular pressure is linearly related to the applied HIPR pressure whether the latter is 30, 50, or 75 mm Hg. The slopes relating peak intraocular pressure to initial intraocular pressure at different HIPR settings are parallel. Use of the HIPR at settings greater than 30 mm Hg and an initial IOP of greater than 30 mm Hg could compromise ocular vascular perfusion.

ISSN:0271-3683    

DOI:10.3109/02713688609015127

出版商:Taylor&Francis    

年代:1986

数据来源: Taylor