摘要:

Purpose. Disturbances in neurotransmitter distribution have been observed in cerebral ischemia in the pathophysiologic process of excitotoxicity. The goal of this study was to examine the effect of pressure-induced retinal ischemia on the distribution of the retinal neurotransmitters glutamate andγ-aminobutyric acid (GABA) within the rat retina.Methods. Animals were subjected to increased intraocular pressure of 110 mm Hg for 45 min using an intracameral hydrostatic pressure device. The distribution of glutamate and GABA immunoreactivity (IR) was determined at 0, 2, 4, 8 and 24 hrs after reperfusion by immunogold with silver intensification.Results. Three phases of neurotransmitter immunoreactivity patterns were discernible following retinal ischemia. Immediately following reperfusion (Phase I), a shift of GABA-IR from inner retinal neurons to the Müller cells and their processes was noted. In contrast, despite marked decreases in neuronal glutamate-IR, a less pronounced shift of glutamate-IR to the Müller cells was simultaneously noted. This shift of neurotransmitter IR to the Müller cells was transient with the gradual reappearance of IR within the inner retinal neurons noted 2–8 hrs after reperfusion (Phase II). Phase III began at 8 hrs after reperfusion with progressive loss of GABA-IR noted in the inner retina; by 24 hrs, secondary loss of inner retinal glutamate-IR was evident with corresponding dropout and pyknosis of inner retinal neurons apparent.Conclusions. The distribution of glutamate-IR and GABA-IR was significantly altered following retinal ischemia. The initial alterations noted in Phase I suggested that the regulation of glutamate by Muller cells was disrupted by this ischemic insult leading to glutamate excitotoxicity, and delayed neuronal cell degeneration as evidenced by the subsequent loss of inner retinal immunoreactivity in Phase III.

ISSN:0271-3683    

DOI:10.3109/02713689609008898

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

Purpose. The purpose of this study was to determine whether HIV-1 and HHV-6 are capable of infecting and inducing morphological and ultrastructural changes in corneal epithelial cellsin vitro.Methods. Primary and transformed corneal epithelial cell cultures were infected with HIV-1 or HHV-6in vitroand analyzed for the presence or absence of viral antigens, DNA sequences, viral particles and inclusions.Results. HIV-1 antigens were detected in 8% of the HIV-1 infected cells and early HHV-6 antigens were present in 12% of the HHV-6 infected cells. The presence of viral DNA sequences in the cultures confirmed these findings. Cells infected with HIV-1 morphologically were not different from uninfected cells, whereas the morphology of HHV-6 infected cells was very similar to cells infected with other human herpesviruses. Cytoplasmic tubuloreticular inclusions were detectable in corneal epithelial cells infected with HIV-1 and intact viral particles were visible only in PBMC used to recover HIV-1 from these cultures. Viral inclusions were also observed in corneal epithelial cells infected with HHV-6.Conclusion. These data indicate that HIV-1 and HHV-6 are capable of infecting corneal epithelial cellsin vitro, but the viruses are not entering these cells via CD4 or galC receptors. This basic information is important in determining the pathogenic mechanism(s) involved in the development of AIDS-associated corneal disorders.

ISSN:0271-3683    

DOI:10.3109/02713689609008899

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

Purpose. To evaluate human tear fluid for transforming growth factor beta isoforms 1 and 2 (TGF-β1 and TGF-β2).Methods. To accomplish this, human tears were evaluated for TGF-βs by quantitative antibody sandwich ELISA (sELISA), mink lung epithelial cell (MLEC) growth inhibition bioassay and western blotting. Various physical and chemical treatments were used to activate TGF-βin these assays.Results. TGF-βs could not be detected in untreated or heated tears by sELISA; however, mean TGF-βl concentrations of 38.5 ng/ml and TGF-β2 concentrations of 2.32 ng/ml were detected in acid-activated tears by sELISA. Furthermore, 10.54 ng/ml of TGF-β1 and 3.98 ng/ml of TGF-β2 were detected in tears treated with the mucolytic agent, acetylcysteine. Total TGF-βbioactivity in human tears measured by the MLEC assay was found to be 13.04 ng/ml in untreated tears and 24.85 ng/ml in acid-activated tears. Approximately one-half TGF-βin tear specimens was biologically active (mean = 52%, range 39–71%). Total tear TGF-βbioactivity could be completely neutralized by recombinant human TGF-β1 latency associated peptide (rh TGF-β1 LAP). Mean neutralization of tear TGF-βbioactivity was 83% by TGF-β1-specific antisera, and was 13% by TGF-β2-specific antisera. Immunoreactive TGF-βbands at approximately 12.5 and 95 kD were observed in immunoblots of reduced acidified tears. A high molecular weight (MW) TGF-βband (>2O3 kD) was noted in untreated tears; however, this band disappeared following treatment with acetylcysteine.Conclusions. The results of these studies indicate that TGF-β1 and TGF-β2 are present in human tear fluid, and TGF-β1 is the predominant isoform. There appears to be factors in human tears capable of binding TGF-β.

ISSN:0271-3683    

DOI:10.3109/02713689609008900

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

Purpose. Transforming growth factor beta (TGF-β) isoforms 1 and 2 have recently been detected in stimulated human tear fluid. The purpose of this study was to determine if these TGF-βs are produced and secreted by the lacrimal gland.Methods. To accomplish this, reverse transcriptase polymerase chain reaction (RT-PCR) was used to detect expression of TGF-pl and TGF-β2 mRNAs in normal human and rabbit lacrimal gland biopsies. Northern blot analyses were used for comparing the relative levels of expression of these TGF-βmRNAs in rabbit lacrimal glands. Human lacrimal gland biopsies were evaluated by immunohistochemistry for production of TGF-β1, TGF-β1 latency associated peptide (LAP), and TGF-β2 proteins. Super-natants of unstimulated and carbachol-stimulated human lacrimal gland explant cultures were evaluated for secretion of TGF-β1 and TGF-β2 by ELISA.Results. TGF-β1 and TGF-β2 mRNA expression was found in all human and rabbit lacrimal gland specimens by RT-PCR. A greater level of expression of TGF-β1 than TGF-β2 mRNA in the rabbit lacrimal gland was noted by Northern blot. In human lacrimal gland biopsies, TGF-β1 and TGF-β1 LAP were detected in acinar and ductal epithelia by immunohistochemistry. TGF-β2 specific antibodies stained a small percentage of acinar and ductal epithelia, as well as material within the lumens of tubulo-acinar complexes in one-third of these glands. TGF-β1 was detected in supernatants of human lacrimal gland explants, and the concentration of TGF-β1 increased by an average of 280% after carbachol-stimulation (p = 0.004). TGF-β2 could not be detected in unstimulated or stimulated human lacrimal gland explant supernatants.Conclusions. The results of these experiments indicate that TGF-βl and TGF-β2 are produced by and TGF-β1 is secreted by the human lacrimal gland. They also suggest that the lacrimal gland may be one source of TGF-βin human tear fluid.

ISSN:0271-3683    

DOI:10.3109/02713689609008901

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

Purpose. Detection and precise quantification of changes in retinal vessel diameter by image analysis techniques is important in a number of fields of research. The retinal vessels have been shown to exhibit pulse related changes in diameter. These may need to be taken into account when studying diameter changes due to other causes. This study examined the effect of using multiple fundus photographs with and without electro-cardiographic synchronisation on the size and statistical significance of changes in mean retinal vessel diameter.Methods. Twelve fundus photographs spaced throughout the cardiac cycle by electrocardiographic synchronisation were taken in 10 normal volunteers: (a) at rest, (b) during isometirc exercise, and (c) during oxygen inhalation. Vessel diameters were measured using a computer assited image analysis system. Subsequently smaller sample sizes, with and without electrocardiograph synchronisation were modelled from the available data.Results. With a group of ten subjects six or more electrocardiograph synchronised photographs enabled reliable detection of small diameter changes (1.4%) induced by isometric exercises while other methods either failed to detect change or were unreliable at doing so. With six subjects twelve synchronised photographs were required to reliably detect a change of the same magnitude. Larger diameter changes (5.4%) were detected by any method including a single unsynchronised photograph.Conclusions. Multiple frame electrocardiograph synchronized fundus photography permits more accurate detection of small changes in retinal vessel diameter.

ISSN:0271-3683    

DOI:10.3109/02713689609008902

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

Purpose. We previously reported that intravitreal injection of 0.5μg of endothelin-1 (ET-1) caused both a sustained reduction of intraocular pressure (IOP) and decreased aqueous production in the rabbit eye. On the theory that these effects might have resulted from a sustained reduction of blood flow to the ciliary body due to ET-1-mediated vasoconstriction, in the present study we attempted to determine if ET-1 causes any changes in the vascular caliber of the iris-ciliary body.Methods. ET-1 solution (0.5μ.g) was injected into the vitreous of one eye of each of 10 albino rabbits; the same amount of vehicle was injected into the contralateral eyes. One h following these injections in five of the rabbits and 24 h following them in the other five rabbits, ocular microvascular castings were obtained under controlled physiologic conditions, and the amount of vasoconstriction of the arterioles branching from the major arterial circle of the iris (MAC) and supplying the iris-ciliary body was measured by a scanning electron microscope and expressed as a percentage.Results. The ET-1 caused a statistically significant focal vasoconstriction in the treated eyes as compared with the contralateral, control eyes (9.9% at 1 h and 6.2% at 24 h; both P =. 0001).Conclusions. Intravitreally injected ET-1 caused statistically significant, but only mild vasoconstriction of the arterioles supplying the ciliary processes.

ISSN:0271-3683    

DOI:10.3109/02713689609008903

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

Purpose. The aim of this study was to evaluate the function of the neurosensory retina in Best vitelliform macular dystrophy (BMD) by recording the focal electroretinogram (FERG) fundamental and 2nd harmonic components, which are known to be dominated by receptoral and postreceptoral activity, respectively.Methods. FERGs were recorded in response to a uniform field (9×9 deg) flickered sinusoidally at either 8 Hz or 32 Hz (peak frequencies for the 2nd and fundamental harmonic, respectively). The fundamental component of the response to the 32-Hz stimulus and the 2nd harmonic of the response to the 8-Hz stimulus were measured in their amplitudes and phases. The fundamental-2nd harmonic amplitude ratio was taken as an index of the relative changes in the FERG components. Eleven patients with BMD and vitelliform stage macular lesions were evaluated. Results were compared with those obtained from 13 patients with Type 2 Stargardt macular dystrophy (STD) according to the Noble and Carr classification, and 29 normal control subjects. Four BMD and four STD patients were also followed electrophysi-ologically over a 48 month period.Results. Compared to controls, BMD patients showed losses of both FERG fundamental and 2nd harmonic amplitudes, and an increase in the fundamental-2nd harmonic ratio. STD patients also showed losses of both fundamental and 2nd harmonic, but the fundamental-2nd harmonic ratio was normal. In BMD patients, but not in those with STD, the fundamental amplitude tended to decrease over the follow-up period.Conclusions. The results indicate that BMD involves neurosensory abnormalities early in the disease process. The increased fundamental-2nd harmonic ratio suggests that a postreceptoral dysfunction may be present in addition to that of photoreceptors. This differs from STD, where losses appear to affect primarily the receptoral retina. Receptoral losses in BMD may progress throughout the medium-term follow-up.

ISSN:0271-3683    

DOI:10.3109/02713689609008904

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

Purpose. To establish a method for evaluation of less irritating contact lens materials by dynamic contact with cornea, we examined epithelial and endothelial cell injury to the porcine cornea caused by rotatory rubbing with four kinds of hard contact lenses (HCL).Methods. The HCLs used were (1) polymethylmethacrylate (PMMA) HCL, (2) gas-permeable HCL composed of a graft co-polymer of dextran derivative and methylmethacrylate (MMA) (Suncon Mild II™, 12 Dk), (3) gas-permeable HCL composed of a graft co-polymer of dextran derivative, a monomer containing silicone, a monomer containing fluorine and MMA (New Dx HCL-136, 32 Dk), and (4) gas-permeable HCL composed of a monomer containing silicone, a monomer containing fluorine and MMA (RGPL-A, 216 Dk). Using a specially designed apparatus, we produced a standardized injury to the epithelium or endothelium of porcine corneas by holding the HCL against the corneal surface while rotating the lens rapidly.Results. After rotatory rubbing of the HCL on the epithelium, the degree of rose bengal staining of the epithelial cells, indicating degeneration of the cells and mucin detachment, were significantly different among these HCLs (New Dx HCL-136

ISSN:0271-3683    

DOI:10.3109/02713689609008905

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

Purpose. Assessment of the tear film meniscus is a quantitative, minimally invasive, direct measurement of tear film quantity. The aim of this study was to assess the efficacy of tear meniscus parameter measurement in the diagnosis of dry eye.Methods. Tear meniscus radius of curvature, height, width and cross-sectional area (TMC, TMH, TMW, XSA) were determined by photographing an optic section of the inferior tear meniscus (colored with a min volume of fiuorescein) at 120 x magnification, and then scanning developed images into a computer analysis program. Fifteen dry eye subjects and 15 age-matched controls were assessed. Dry eye subjects satisfied the criteria of a rose bengal staining score≥1, and a mean phenol red thread 15 s wetted length≤10 mm.Results. TMC, TMH and XSA were all reduced in magnitude in the dry eye group compared to the control group (mean±SD; TMC: 0.314±0.160 mm vs. 0.545±0.259 mm, TMH: 0.244±0.089 mm vs. 0.461±0.173 mm, XSA: 0.0082±0.0048 mm2vs. 0.0176±0.0103 mm2, ANOVA, p<0.05). Both TMC and TMH showed good diagnostic accuracy (166.7% and 160% respectively), with a dry eye referent value of≤0.35 mm for each parameter. TMC and TMH also showed strong correlations with the cotton thread test, non-invasive breakup time, and ocular surface staining scores (p<0.01). TMH was the most powerful predictor of tear film insufficiency.Conclusions. This study has shown tear meniscus assessment to be a useful alternative to existing tests for dry eye.

ISSN:0271-3683    

DOI:10.3109/02713689609008906

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

Purpose. To evaluate postnatal developmental changes in the amounts of retinal glutamate. glutamine and GABA, and in the distribution of retinal glutamine in the rat.Methods. Free amino acids were extracted from rat retinas of different postnatal stages, and the concentrations of glutamate, glutamine and GABA were determined by HPLC. Also, anti-jilutamine antibody was raised and an immunocytochemistry was performed with paraffin-embedded retinal sections in parallel with free amino acid analyses.Results. Glutamate occurred in high concentrations at the birth and showed a stable pool, while glutamine and GABA remained low until postnatal day 3 or 5, and gradually increased in the developing rat retinas. Glutamine immunolabeling was observed in the retinal pigment epithelium and in a subpopulation of presumed amacrine cells in the early postnatal days. It was also found in Miiller cells and in some ganglion cells or displaced amacrine cells in the ganglion cells layer. Glutamine immuno-labeling was transiently observed also in horizontal cells. Finally, the immunolabeling was dominant in the inner and outer plexi-form layers in the adult retinas.Conclusions. Postnatal developmental increase in the levels of glutamine and GABA might be dependent on the maturation of neurons or glial cells that possess the activity of the key enzymes of each amino acid. It was suggested that an expression of glutamine immunolabeling can be a marker of neurons that utilize glutamine as a precursor for glutamate or GABA, and of Müller cell maturations in postnatal early stage of the retina, while it changes to demonstrate the locations of glutamine cycle in the retina with adult characteristics.

ISSN:0271-3683    

DOI:10.3109/02713689609008907

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor