摘要:

Thein vitrotranscriptional activity of the two 6-crystallin genes (5′-61–62–3′) of the chicken was studied in a whole Hela cell extract. Both the 61 and 62 promoters were recognized by RNA polymerase II in this heterologous system. The major RNA initiation site from the 61 promoter was the samein vitroas that which occursin vivo, as judged by mapping with S1-nuclease, although other minor initiation sites upstream and downstream of the major initiation site were noted. A primer extension experiment showed that the longest RNA synthesizedin vitrofrom a 62 template initiated near the beginning of the first exon. The 61 promoter was several-fold stronger than that of 62 under the presentin vitroconditions. Transcription from the $dL1 promoter was abolished by a competitor fragment (c'-II; includes -328 to -63) purified from the 62 promoter, indicating that one or more common transcription factors binding upstream from the TATA box are required forin vitrofunction of the two $dL-crystallin promoters. Thus, in the Hela cell extract both $dL-crystallin genes contain a functional promoter. We consider the possibility that the single 5'CCAAT3′sequence present in the $dL1 promoter (but lacking in the $dL2 promoter) may contribute to its greater core activity under our conditions. The greater promoter activity of the $dL1-crystallin gene in the Hela cell extract was not sufficient to account for the large ratio of $dL1 to $dL2 mRNA (-50 to 100) in the embryonic chicken lens.

ISSN:0271-3683    

DOI:10.3109/02713688809031782

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

A rabbit model for the study of hypersensitivity to thimerosal was established in order to develop better techniques for screening patient sera and tears for specific antibodies to lens care reagents. Thimerosal (sodium ethylmercury thiosalicylatelate) was successfully coupled to several protein carriers using a water soluble carbodiimide which linked the carboxyl group of thimerosal to free amino groups of the carrier proteins. Thimerosal was also shown to spontaneously react with proteins as detected by the irreversible binding of mercury to the protein carrier. Immunization of rabbits with the chemically coupled thimerosal resulted in the production of antibodies which specifically reacted with thimerosal. The rabbits also manifested delayed and immediate forms of hypersensitivity to the thimerosal conjugates. The ELISA assay for specific serum antibodies was found to be a sensitive, reliable and specific screening tool However, there was no immunological cross reactivity between the chemically coupled thimerosal and the spontaneously coupled thimerosal. Therefore, the epitopes produced by these two reaction mechanisms were probably immunochemically different even though both contained detectable thimerosal derived mercury.

ISSN:0271-3683    

DOI:10.3109/02713688809031783

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

The composition of human beta-crystallins displayed specific changes with age and region of the lens. 27kD and 29kD human beta-crystallin subunits were singled out for study. The 29kD beta-crystallin subunit constituted approximately 10% of the total lens crystallins at 8 months of fetal life. Its accumulation decreased steadily to 3.3% during postnatal year 1, to 0.5% by year 5 and to 0.3% thereafter. At all postnatal ages, however, it persisted mainly in the superficial fibers. Thus in a 17-years old lens it made up 1.3% of the superficial fiber soluble protein but was already absent from deep cortical and nuclear fibers. The 27kD subunit increased steadily from 3.5% at 8 months fetal to 7% at year 5; it then decreased steadily to 1.2% in the 86-years old lens. It persisted in all regions of the lens but decreased markedly in the deep cortical and nuclear fibers with increasing age beginning at 5–17 years of age. Studies on the oligomeric structure of human beta-crystallin must take into account age-related changing quantitative patterns in the subunit polypeptide composition of this lens protein.

ISSN:0271-3683    

DOI:10.3109/02713688809031784

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

Intrastromal injection with human serum albumin (HSA) in the rabbit cornea induced edema and a ring-shaped leukocyte infiltrate followed by neovascularization.The effect of topically administered lipoxygenase and cyclooxygenase inhibitors on this inflammatory keratitis was studied.The lipoxygenase inhibitors Bay 08276 and Rev 5901 and the cyclooxygenase inhibitor suprofen were given as 1% eye drops three times daily during the experiment. In eyes treated with lipoxygenase inhibitors leukocyte infiltration, neovascularization and edema formation decreased. In eyes treated with a cyclooxygenase inhibitor the period of neovascularization was slightly shortened and corneal edema decreased. No influence on leukocyte infiltration was seen.

ISSN:0271-3683    

DOI:10.3109/02713688809031785

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

A series of novel“soft”β-blockers was designed and synthesized based on the“inactive metabolite approach”. Accordingly, the acidic metabolite of metoprolol was converted into various lipophilic esters. The new compounds were tested for their effect on the intraocular pressure (IOP) of rabbits using the ultra-short acting B-adrenergic antagonist“Esmolol®”as a reference compound. Most of the tested compounds displayed a higher and a more prolonged ocular hypotensive activity than the reference methyl ester. The adamantaneethyl ester 2 emerged as the best potential candidate for ophthalmic use as an antiglaucoma agent. This compound exhibited an effective and long lasting ocular hypotensive activity without local irritation to the eye. At the same time, it showed a very fast rate of hydrolysis in human blood (t1/2= 7.0 minutes) to the inactive acid metabolite. This makes possible effective separation of the desired ocular activity from unwanted systemic 3-blocking action. Unilateral treatment with 2 produced reduction in the IOP only in the treated eye, consistent with the mechanism proposed.

ISSN:0271-3683    

DOI:10.3109/02713688809031786

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

Interphotoreceptor retinoid-binding protein (IRBP), a retinal specific antigen, induces experimental autoimmune uveoretinitis (EAU) when injected into Lewis rats. Here we report that certain cyanogen bromide fragments of IRBP are capable of inducing EAU. Bovine IRBP, reduced and S-carboxymethylated, was subjected to cyanogen bromide cleavage. This CNBr digest was subjected to reversed-phase high performance liquid chromatography. Three fragments were purified to apparent homogeneity. These three fragments were subjected to gas-phase amino-terminal sequencing analysis. All three yielded single sequences, confirming their purity. On the basis of this amino-terminal sequencing and sequencing of cDNAs encoding bovine IRBP, two of these sequences, named CB-58 and CB-71, were localized to the C-terminal one-third of the IRBP molecule, whereas the third, a subfragment thought to result from cleavage at a tryptophan residue and named CB*-47, was localized to the N-terminal one third of the protein. CB-71 and CB*-47 shared a strong homology, suggesting a putative internal gene duplication event in the evolution of IRBP. All three of these fragments when injected into Lewis rats caused moderately severe EAU with early onset at relatively low doses. The histopathologic changes induced were indistinguishable from those caused by the intact protein. It would seem, therefore, that bovine IRBP contains multiple uveitogenic sites.

ISSN:0271-3683    

DOI:10.3109/02713688809031787

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

A cross-sectional study of changes in cat corneal endothelial cell morphology with age was conducted. The central corneal endothelium of 12 kittens and 70 adult cats was photographed using specular microscopy. Endothelial cell density (ECD), coefficient of variation of cell size (used as an index of Dolymegefhism), and cellular shape factor (perimeter2/area) were determined for each animal and analysed as a function of age. We found a rapid non-linear decrease in ECD and polymegethism in the first nine months of post-natal life. Subsequently there was a slight central cell loss of 11 cells/mm2or 0.37% per year during adult life which was not statistically significant. However, polymegethism increased significantly with age during adult life. The shape factor for endothelial cells was 13.61 throughout adult life, indicating that the cat corneal endothelium consists predominantly of six-sided cells. Possible explanations for the finding of no significant decrease in cell density with age could include the higher peripheral ECD in the cat which may compensate for central loss, the short life expectancy of the cat and the large individual variation in corneal diameter.

ISSN:0271-3683    

DOI:10.3109/02713688809031788

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

A modified procedure for measuring human lymphocyte responses to retinal antigens was introduced and found to be highly sensitive. The main modifications are the use of round bottom culture wells, high antigen concentrations (up to 100μg/ml) and extended incubation time (up to 9 days). Using this procedure, the majority of patients with uveitis, as well as a large proportion of healthy donors were found to respond positively (S.I.±2.0) toward S-antigen and interphotoreceptor retinoid-binding protein. The responses to the retinal antigens were further enhanced by enriching the cultured lymphocytes for the helper/inducer subset. The responses to the retinal antigens were inferior to those against tuberculin (PPD), in particular in subjects who had been inoculated with BCG. The“secondary”responses to PPD were always higher in magnitude, were stimulated by markedly lower concentrations of antigen and were detected earlier in culture. The notion that the responses to retinal antigen in healthy donors are“primary”in nature was further supported by the findings that (a) lymphocytes from cord blood samples resembled adult lymphocytes in their response to S-Ag and (b) healthy donor lymphocytes which were prestimulatedin vitrowith S-Ag reacted to this protein by a specific“secondary”fashion. The possible involvement of lymphocytes with reactivity toward retinal antigens in pathogenic autoimmune processes in the eye is discussed.

ISSN:0271-3683    

DOI:10.3109/02713688809031789

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

Tryptophan fluorescence was monitored in whole lenses (and in soluble crystallin fractions derived from these lenses) before and after incubating them in media containing acrylamide or iodide. The effects of exposing one lens to low level broadband UV radiation were compared with the contralateral lens incubated in the dark. In addition we employed13C labeled acrylamide in order to monitor (by NMR spectroscopy) which crystallins were most effected.These studies demonstrate an acrylamide fluorescence quenching effect in whole lenses and extracted lens proteins, which is directly age related, as is the extent of its incorporation and binding to specific lens proteins. Iodide had no effect on TRP fluorescence in whole lenses and a slight effect on the extracted crystallins.These data demonstrate differences in the microenvironment of TRP residues in the various lens crystallins and their relative susceptibility to low level UV radiation exposure at doses approaching the ambient in vivo levels in a“real life”situation. This approach helps to delineate the microenvironment of TRP residues in native proteins and the effects of UV exposure on proteins with buried versus exposed TRP residues.

ISSN:0271-3683    

DOI:10.3109/02713688809031790

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor

摘要:

Experimental nuclear cataract produced by an overdose of sodium selenite exhibited limited proteolysis, including breakdown of main intrinsic polypeptide (MIP26) to 24 and 22 kD fragments (1). Micro-sequencing and site specific immunologic probes were used in the present study to determine regions of cleavage in MIP26 during selenite cataractogenesis. Data suggested that proteolysis occurred in the C-terminus of MIP26. This may have lead to exposure of normally hidden amino acid residues on the C-terminal extension of MIP26. Loss of antigenicity of the N-terminus occurred. These significant changes to the MIP26 molecule might adversely affect communication between lens fiber cells and contribute to selenite cataract.

ISSN:0271-3683    

DOI:10.3109/02713688809031791

出版商:Taylor&Francis    

年代:1988

数据来源: Taylor