Preliminary assessment of a new prototype ultrasound-based hypersonic vitrector (HV) by qualitatively examining the histopathological changes in the retina and vitreous body after pars plana ...vitrectomy (PPV) and its ability to fragment vitreous collagen.
Fourteen porcine cadaveric eyes, 20 eyes in live swine and six human cadaveric eyes underwent PPV using the HV or a pneumatic guillotine vitrector (GV). An additional 4 porcine crystalline lenses were touched with either the HV or GV for 1 minute. Following PPV, human vitreous was removed and processed for electron microscopy (EM). Eyes and lenses were fixed and sectioned for light microscopy (LM).
There were no macroscopic retinal or optic nerve defects associated with either HV or GV PPVs. Cadaveric retinal specimens showed separation of the inner limiting membrane (ILM) and vacuolization and fragmentation at the nerve fiber layer (NFL) and the ganglion cell layer (GCL). ILM fragmentation and separation were found after PPV in live swine with both vitrectors. Small disruptions of the posterior capsule or structural lens defects were found after HV touch. The EM analysis revealed more fragmentation of human vitreous collagen fibrils after HV compared to GV PPV.
LM and EM analysis of retina, vitreous, and crystalline lens after PPV showed similar morphological changes using the HV or the GV. Vitreous fragmentation appeared more effective with the HV. Overall this study suggests that the HV may be a promising new technology. More work is needed to quantitatively assess its safety and efficacy.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Qualitatively assess the possible delayed structural, macroscopic and microscopic changes in the neuro-retina, retinal vasculature, retinal pigment epithelium (RPE) and optic nerve head (ONH) after ...pars plana vitrectomy (PPV) surgery using a new hypersonic vitrector (HV).
Eight live porcine eyes underwent PPV using either the HV or a conventional pneumatic guillotine vitrector (GV). The un-operated fellow eye from each pig was used as an external control. The pigs were post-operatively kept alive for 30 days before termination and enucleation of the eyes. Prior to enucleation, all eyes underwent examination of the lens and indirect ophthalmoscopy. Enucleated eyes were fixed in formalin, examined macroscopically and processed for histological assessment. Microscopic analysis included assessment of neuro-retina, retinal vasculature, RPE and ONH, as well as observation for any morphological intraocular changes. Comparison was made between: (1) treated and untreated areas of the same eye (internal control) (2) different areas within the same eye operated on using different vitrector settings (3) eyes operated on with the HV and GV (4) eyes receiving surgery and the fellow un-operated eye (external control, same pig).
All lenses had remained clear at 30 days into the postoperative period. On indirect ophthalmoscopy, the retina had remained attached in all eyes with no visible changes to the neuro-retina, retinal vasculature, RPE or ONH. Two eyes showed localized RPE depigmentation secondary to previously documented intraoperative retinal touch. The Morphological changes in the retinal layers above depigmented RPE were no different from retinal change elsewhere. There were mild and similar microscopic changes observed in the neuro-retina, retinal vasculature, RPE or ONH associated with either the HV or GV PPVs. Preliminary histological findings revealed no significant differences between eyes operated on with the HV and those operated on the GV.
At 30 days into the postoperative period, there seemed to be similar morphological changes attributable to the use of HV and GV. Therefore, the HV promises to be a new alternative to the currently commercially available GV for PPV.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
To compare morphologic features of keratoconus as observed in vivo with a slit scanning confocal microscope and in vitro using light microscopy.
Slit scanning confocal microscopy (CM) was used to ...evaluate the central cornea of 29 keratoconic subjects (mean age, 31 +/- 10 years; range, 16-49). Light microscopy (LM) examination was performed on 2 of the keratoconic corneas post-keratoplasty.
With CM, the epithelium appeared more abnormal with increasing severity of keratoconus. In severe disease, the epithelium displayed the following characteristics: superficial cells were elongated and spindle shaped, wing cell nuclei were larger and more irregularly spaced, and basal cells were flattened. These findings were confirmed by LM. Images obtained using CM revealed disruption to Bowman's layer and the occasional presence of epithelial cells and stromal keratocytes. This was shown with LM to be due to breaks in Bowman's layer. Stromal haze and hyperreflectivity observed with CM corresponded with apical scarring seen on slit-lamp biomicroscopy. Hyperreflective keratocyte nuclei observed with CM are thought to indicate the presence of fibroblastic cells seen with LM. Increasing levels of haze detected with CM were found with LM to be due to fibroblast accumulation and irregular collagen fibers. Descemet's membrane appeared normal with both CM and LM. Evidence of endothelial cell elongation was apparent in 1 subject with CM.
The current study confirms the application of CM for assessing morphologic alterations to the epithelium, Bowman's layer, and stroma in keratoconus. Many of the tissue changes observed with CM could be reconciled with observations made using LM. This work provides a framework against which tissue changes in keratoconus can be studied in a clinical context in vivo using CM.
Drusen are a feature of age-related macular degeneration (AMD). Lesions similar in appearance to drusen are also found in the fundi of patients with membranoproliferative glomerulonephritis type II ...(dense deposit disease, DDD). The lamina densa of the glomerular basement membrane, in DDD, is transformed into an electron-dense structure by deposition of microscopically homogeneous material. Our study sought to compare the saccharide composition of drusen and dense deposits in the formalin-fixed, paraffin-embedded tissue from the eye and kidney. Six eye specimens were obtained from patients diagnosed with AMD but another eye was obtained from a patient with partial lipodystrophy, who died after renal failure presumably because of DDD. The kidney specimens were from three biopsy-proven cases of DDD. Glycosylation patterns were measured by the binding of 19 biotinylated lectins before and after neuraminidase pre-treatment. High mannose, bi/tri-antennary non-bisected and bisected complex N-glycan, N-acetyl glucosamine, galactose, and sialic acid residues were found in both drusen and dense deposits. Treatment with neuraminidase exposed subterminal galactose in both sites and sparse N-acetyl galactosamine residues in drusen alone. Our study found similar pathologic oligosaccharide structures in the eye and kidney, suggesting that drusen may be a common end result of retinal and glomerular disease.
Creutzfeldt-Jakob disease (CJD) primarily affects the brain. This study was conducted to assess the possible involvement of the eye in sporadic and variant CJD by testing for the presence of the ...disease-associated, protease-resistant isoform of the prion protein (PrP(Sc)) in ocular tissue.
Human eyes from donors with CJD and non-prion neurodegenerative disease control eyes were studied. In situ hybridization and Western blot analysis were used to determine the normal pattern of cellular prion protein (PrP(C)) expression. Western blot analysis and immunohistochemistry were then used to determine the localization, abundance, and isotype of PrP(Sc) in eyes in CJD.
PrP(C) was expressed in the nuclear layers of the retina. In both the sporadic and variant forms of CJD, PrP(Sc) accumulated throughout the synaptic layers of the retina. The levels of PrP(Sc) found in the retina were comparable with those found in the brain. Lower levels of PrP(Sc) could be found in the optic nerve, but no PrP(Sc) was detectable in other ocular tissues. The glycoform ratio of PrP(Sc) in the retina did not correspond to that found in the brain.
Presumptive centrifugal spread of PrP(Sc) from the brain through the optic nerve occurs in two major types of CJD. PrP(Sc) is a marker of CJD infectivity. Given that routine decontamination may not remove PrP(Sc) from surgical instruments, a careful risk assessment should be made of possible iatrogenic spread of sporadic and variant CJD after surgery to the retina or optic nerve.
Two forms of autosomal-dominant lattice corneal dystrophy (LCD), types I and IIIA, have previously been shown to be caused by different mutations within the transforming growth factor, beta-induced (
...TGFBI) gene. A clinical and molecular analysis of three unrelated kindreds with a clinically distinct late-onset LCD was undertaken to determine whether this phenotype is also caused by mutations within the
TGFBI gene.
Experimental study.
Thirty-two members of three kindreds with corneal dystrophy. DNA from 100 normal control subjects was used as a control population.
Members of three kindreds with LCD were examined clinically, and blood samples were taken for DNA analysis. Mutation analysis was undertaken on all individuals for the coding region of the
TGFBI gene by means of polymerase chain reaction (PCR) followed by single-stranded conformation polymorphism/heteroduplex analysis, subcloning, and sequencing.
Detection of mutations within the
TGFBI gene.
Clinical examination revealed a form of LCD that was bilateral in all but one case, with onset around the fourth to fifth decade. The majority of cases showed significant asymmetry, and in one case there was evidence of onset directly after minor superficial corneal trauma. Molecular analysis in all families demonstrated sequence changes within exon 14 of the
TGFBI gene on chromosome 5q31, at codon 622 in family 3, and at codon 626 in families 1 and 2, which are presumed to be responsible for the disease.
Previously, a late-onset form of LCD, termed IIIA, was shown to be caused by a P501T mutation in exon 11 of
TGFBI. The authors present the first description of mutations in exon 14 of
TGFBI causing an LCD, also of late onset. Although the condition presented is morphologically and histopathologically typical of an isolated lattice dystrophy, the age of onset and clinical course is not typical of type I, III, or IIIA lattice dystrophy. This, in conjunction with recent developments in our understanding of the molecular genetics of these disorders, calls into question the usefulness and validity of the current classification of the isolated lattice dystrophies.
<正>Dear Editor,We present a case of non-keratinising undifferentiated nasopharyngeal-type carcinoma(UNPC)of nasolacrimal sac and review the previously reported cases and their treatment options ...and prognosis.Squamous cell carcinoma with a characteristic lymphoid stroma is a type of poorly differentiated carcinoma typically occurring in the nasopharynx1.Non-keratinising UNPC,so called lymphoepithelioma-like carcinoma(LELC),of the lacrimal
PURPOSE:To relate the clinical signs, histopathologic features, and in vivo confocal biomicroscopy findings of a case of stromal microsporidial keratitis and to describe the use of in vivo confocal ...microscopy to monitor treatment effect.
METHODS:An immunocompetent male patient presented with unilateral indolent stromal keratitis. Stromal microsporidiosis was confirmed after corneal biopsy. He underwent examination that used in vivo confocal microscopy (Heidelberg Retina Tomograph II and Rostock Cornea Module) before and after treatment with topical fumagillin and oral albendazole. Clinicopathologic correlation of the confocal scan was performed.
RESULTS:Corneal biopsy showed extracellular microsporidium spores aligned along keratocytes and corneal lamellae. In vivo confocal scans showed similar morphology, with bright dots aligned along keratocytes. Treatment with antimicrobials and topical steroid gave resolution of active keratitis, correlating with disappearance of the bright spores on repeat in vivo confocal scanning.
CONCLUSIONS:The in vivo confocal microscopy appearance of microsporidial keratitis corresponds to the histologic features from biopsy material. Treatment response may be monitored by using this technique, although definitive diagnosis requires corneal biopsy.
Drusen are deposits located between the retinal pigment epithelium and Bruch's membrane in age-related maculopathy. They are believed to be photoreceptor byproducts that are incompletely metabolized ...by the retinal pigment epithelium. This study therefore compares the lectin histochemistry of drusen, photoreceptors, retinal pigment epithelium, and Bruch's membrane.
Semithin sections of three eyes with age-related maculopathy were studied using 19 biotinylated lectins and an avidin-peroxidase-revealing system with and without neuraminidase pretreatment.
High mannose, bi and tri-antennary nonbisected and bisected complex N-glycan, N-acetyl glucosamine and galactose were expressed by drusen, retinal pigment epithelium, Bruch's membrane, and photoreceptors while N-acetyl galactosamine and fucose were absent; treatment with neuraminidase exposed subterminal galactose in both sites and sparse N-acetyl galactosamine residues in drusen alone. Overall, there were striking similarities between the lectin binding of drusen, retinal pigment epithelium, and the photoreceptor outer segments, though cone outer segments were distinct in some features of their O-linked glycosylation.
The results suggest that the pathogenesis of drusen is a combined mechanism, involving photoreceptors, Bruch's membrane, and the retinal pigment epithelium.
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