Biomedical subjects

J V Jester

Publications and source records attributed to J V Jester.

132 records · Page 8Linked to original sources

PubMedDate not supplied

Application of in vivo confocal microscopy to the understanding of surfactant-induced ocular irritation.

The purpose of this study was to assess the ability of in vivo confocal microscopy (CM) to provide noninvasively derived histopathologic correlates of surfactant-induced eye irritation from which specific pathologic mechanisms can be identified and later evaluated in alternative in vitro models. Rats and rabbits, divided into groups of 5, received 10 microliters of an anionic or cationic surfactant in one eye with the other eye used as a control. At specified times, eyes were examined and scored for ocular irritancy using a penlight and slit-lamp. Subsequently, corneas were evaluated by in vivo CM to evaluate epithelial layer thickness and surface epithelial cell area, corneal thickness, depth of necrosis, inflammation, fibrosis, and endothelial injury. At 3 hr, the anionic surfactant produced slight irritation with peak scores of 12.4 and 8.0 out of a possible 110 in the rats and rabbits, respectively. In vivo CM revealed changes limited to the corneal epithelium that decreased in thickness to 78% in rats and 81% in rabbits at 3 hr. This decrease in the thickness correlated with a significant decrease in surface epithelial cell area from 2,061 +/- 395 microns2 to 567 +/- 330 microns2 in the rats and 1,523 +/- 185 microns2 to 934 +/- 71 microns2 in the rabbits (p < 0.005 and 0.005, respectively). The cationic surfactant produced severe irritation in both the rats and rabbits with peak scores of 85.4 and 80.2 occurring at day 2, respectively. In vivo CM in the rats showed complete loss of corneal epithelium, lysis of keratocytes, and loss of corneal endothelium. In the rabbits, injury appeared limited to the anterior cornea with complete loss of epithelium and loss of keratocytes extending to 52% of the corneal thickness. These findings establish the application of noninvasive, in vivo CM to qualitatively and quantitatively characterize the pathobiology of ocular irritation in situ. This information will be important in the development and evaluation of mechanistically based in vitro alternatives for ocular irritancy testing.

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PubMedDate not supplied

Use of in vivo confocal microscopy to understand the pathology of accidental ocular irritation.

In vivo confocal microscopy (CM) provides a unique ability to section optically through living, intact tissues and organs to characterize qualitatively and quantitatively pathological changes in 4 dimensions (x, y, and z, and time). It involves the capture of real-time images without the need for excision, fixation and processing. In vivo CM principally has been used for evaluation of eyes in patients and laboratory animals but has potential application to studies of other tissues/organs. In vivo CM is being used in human ophthalmology clinics. It has been used as a research tool for quantitative, in situ measurement of corneal wound contraction, fibroblast migration, corneal endothelial cell migration, corneal epithelial cell size and desquamation following contact lens wear and surgery, and the assessment of corneal surface toxicity following application of commonly used ophthalmic preservatives. In vivo CM allows us to (a) characterize changes to a light microscopic (i.e., cellular) level; (b) quantify changes objectively: (c) conduct studies of injury and repair in the same animal and directly correlate microscopic changes to clinical observations over time as this technique is used in the living animal; and (d) conduct comparative studies in humans. Here we present a brief overview of in vivo CM and how we are using it to provide noninvasive, in situ qualitative and quantitative histopathologic characterization of accidental ocular irritation. Our intent is to provide an awareness of this relatively new methodology and one practical application of its use in research. The goal of our work is to provide objective, quantitative data for use in developing and validating mechanistically based in vitro replacement tests.

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PubMedDate not supplied

Confocal microscopy of the living eye.

Confocal microscopy is an imaging paradigm that allows optical sectioning of almost any material with increased axial and lateral spatial resolution and better image contrast. We have applied this technology to the study of the living eye of cats, albino rabbits, and humans. The technique allows in vivo, noninvasive, real time images of the eye at magnifications (630x) which allow resolution of anatomical detail at the cellular level. In this paper we report details of our current instrument techniques and some of our results. The past development, present state-of-the-art, and projected future advances and applications of this novel microscopy are discussed. Preliminary observations are reported for all layers of the cornea, the limbus, and wound-healing responses in single animals.

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PubMedDate not supplied

Swelling and deswelling of rabbit corneas in response to rigid gas permeable, hydrogel and elastomer contact lens wear.

We determined diurnal variation in corneal thickness in rabbits prior to and following overnight wear of: (i) selected rigid contact lenses with different Dk values; (ii) hydrogel lenses of low and high water content; and (iii) elastomer lenses. The degree of contact lens-induced corneal swelling observed during 24 hours of lens wear, and the rates of deswelling in the subsequent 24 hours, correlated well with the different oxygen transmissibilities of the individual RGP contact lenses. The greatest swelling (21.6 +/- 5.4%) followed the wear of PMMA lenses. The least swelling, 2.9 +/- 4.0%, followed the wear of rigid gas permeable (RGP) Menicon SF-P (melafocon A) lenses, a value nearly identical to the swelling observed in the morning following sleep without lenses, (0.0 +/- 3.1%). By contrast, low-water content hydrogel soft contact lens use was associated with drastic corneal deswelling rates (-15.1 +/- 4.5%) during the hours after lens wear. The difference between these and control corneas was significant by paired t-test (P less than 0.01). Eyes wearing high water content lenses had less deswelling than eyes with their low-water counterparts. Corneal swelling produced by elastomer lenses was similar to that seen with RGP lenses.

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PubMedDate not supplied

Laser and tandem scanning confocal microscopic studies of rabbit corneal wound healing.

The process of corneal endothelial wound healing was studied using laser and tandem scanning confocal microscopy (LSCM and TSCM). Following transcorneal freeze (TCF) injury, rabbit corneas were observed using ex vivo LSCM and in vivo TSCM. LSCM revealed the intracellular actin filament organization which, stained with phalloidin-FITC, in migrating endothelial cells, transformed fibroblast-like cells, stroma keratocytes, and epithelial cells during wound healing in corneal tissue. The TSCM provided sequential spatial observation of morphologic changes from endothelium to epithelium of the cornea during in vivo cellular repair of wound healing noninvasively on the same cornea without animal sacrifice. Ex vivo LSCM supported the morphologic analysis of the in vivo TSCM observations.

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PubMedDate not supplied

In vivo confocal imaging: general principles and applications.

It is well established that confocal microscopy provides higher resolution images with better rejection of out-of-focus information than conventional light microscopy. The optical sectioning ability of confocal microscopy allows images to be obtained from different depths within a thick tissue specimen, thereby eliminating the need for processing and sectioning procedures. Thus, confocal microscopy has made it possible to view biological tissues under more physiologic conditions than previously possible. The most widespread biological application of confocal microscopy has been in the localization of immunofluorescently labeled proteins in cell culture or within excised blocks of tissue. Because of its noninvasive optical sectioning capability, confocal microscopy is also ideally suited to the study of tissue in intact living animals, although the potential in vivo applications of this paradigm have received less attention. In this paper we trace the development of in vivo confocal microscopy and present examples of current capabilities for both research and clinical use.

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