Amino Acid profiles in human tear fluids analyzed by high-performance liquid chromatography and electrospray ionization tandem mass spectrometry

PURPOSE

To identify the 23 amino acid profiles in human tear fluids, and to evaluate whether the ocular disease conditions reflect the amino acid profiles.

DESIGN

Laboratory investigation.

METHODS

We evaluated the concentrations and relative composition of 23 amino acids in tear fluids obtained from 31 healthy volunteers using reversed-phase high-performance liquid chromatography and electrospray ionization tandem mass spectrometry, and compared them with those in plasma and aqueous humor. We also evaluated the tear-fluid amino acid profiles from 33 affected subjects.

RESULTS

The amino acid profiles of the basal tear and reflex tear were found to be similar, and 4 distinct groups of healthy volunteers (male, female, young, and elderly) showed similar profiles. Absolute concentrations of taurine (Tau) and L-glutamine were significantly dominant in these tear fluids. The relative compositions of Tau, L-glutamic acid, L-arginine (Arg), and citrulline in the tear fluid were significantly higher than those in the plasma and aqueous humor. Analysis of the hierarchical clustering of the amino acid profiles clearly distinguished severe ocular surface diseases from non-ocular surface diseases. The relative compositions of Tau, L-methionine, and Arg decreased in severe ocular surface disease subjects compared with non-ocular surface disease subjects.

CONCLUSIONS

Tear-fluid amino acid profiles differ from those in plasma and aqueous humor. Steady-state tear-fluid amino acid profiles might reflect ocular-surface homeostasis and the observed changes of amino acids might have a close relation with the disease conditions on the ocular surface.

HLA expression in choroidal melanomas: correlation with clinicopathological features

PURPOSE

In this retrospective study, we analyzed the relevance of human leukocyte antigen (HLA) expression to clinical behavior of uveal melanoma and correlated it with conventional light microscopic parameters.

METHODS

HLA class I antigen and Beta 2 microglobulin expression were analyzed in 45 primary choroidal melanoma lesions by immunoperoxidase staining with monoclonal antibodies to HLA class I antigen and beta 2 microglobulin and correlated with the known clinicopathological parameters. Immunoanalysis was done by a semi quantitative method. The tumors were divided into 3 groups. Group A: Tumors with no extrascleral extension/no liver metastases, group B: tumors with only extrascleral extension and group C: tumors with liver metastases. For statistical analysis we analyzed the negative, weak (heterogeneous) and the positive expression of HLA and beta 2 microglobulin with known clinicopathological parameters.

RESULTS

In-group A (n = 35) tumors with no extrascleral extension and no liver metastases HLA class I antigen and beta 2 microglobulin are negative (absent staining) in 30 choroidal melanomas. In-group B (n = 4) they are weak (heterogeneous) in 3 tumors. In-group C (n = 6) all the 6 tumors have a positive (bright staining) immunoexpression. No statistical significance was obtained when HLA and beta 2 microglobulin immunoreactivity was compared against largest tumor diameter (LTD), tumor infiltrating lymphocytes (TIL), mitosis and nuclear grade. The difference of HLA class I and beta 2-microglobulin imunoreactivity among the various cell types spindle, mixed and epithelioid was statistically significant (p = 0.003), (p = 0.004). The difference in immunoreactivity between tumors with no liver metastases and tumors with liver metastases was statistically significant (p < 0.001).

CONCLUSIONS

HLA class I antigen and beta 2 microglobulin are negative in melanomas with no extrascleral extension and liver metastases and weak in melanomas with extrascleral extension and are positive in melanomas with liver metastases. HLA expression is independent of the conventional markers in uveal melanoma.

Melanoma-associated spongiform scleropathy: biochemical changes and possible relation to tumour extension

PURPOSE

To investigate biochemical changes of the sclera in eyes with melanoma-associated spongiform scleropathy (MASS), and to analyse possible relationships between these changes and tumour extension.

METHODS

Sections from 364 eyes, enucleated for choroidal and ciliary body melanoma, were examined for MASS and scleral tumour extension. Biochemical analysis was also performed on eight scleral specimens with MASS and eight specimens (controls) from morphologically normal sclera of the same eyes. The scleral thickness of each specimen was measured. Samples were delipidized, dried and weighed. The weight ratios of collagen-related amino acids were calculated based on quantitation by liquid chromatography. Amounts of glycosaminoglycans (GAGs) were determined by electrophoresis.

RESULTS

Melanoma-associated spongiform scleropathy was seen in 140 eyes (38.5%). Tumour scleral extension was observed in 82 eyes. Of these 82 eyes, 75 (91.5%) had MASS (p<0.05). Biochemically, the majority of the main amino acids of the scleral collagen and total proteins were significantly lower in areas with MASS than in the control specimens. Specific GAGs and total GAGs were found in significantly higher concentrations in areas with MASS than in the control specimens. Scleral thickness was also significantly higher in areas with MASS than in the control specimens.

CONCLUSIONS

The reduced content of collagen manifested by decreased amino acids and total proteins indicates collagen degradation in the vicinity of the tumour. The concomitant excessive deposition of GAGs accumulates water and may cause loosening of the already degraded collagen bundles, giving a histopathological picture of MASS. These changes could facilitate tumour cell migration and may explain the high incidence of MASS in eyes with scleral tumour extension.

Ocular and scleral alterations in gene-targeted lumican-fibromodulin double-null mice

PURPOSE

To elucidate the role of leucine-rich proteoglycans lumican and fibromodulin in the sclera.

METHODS

Lumican- and fibromodulin-null heterozygous mice were intercrossed to obtain wild-type (Lum(+/+)Fmod(+/+)), lumican-null (Lum(-/-)Fmod(+/+)), fibromodulin-null (Lum(+/+)Fmod(-/-)), and double-null (Lum(-/-)Fmod(-/-)) littermates. Axial length was measured on enucleated whole eyes, and ocular structural changes were examined by histology. The morphology of collagen fibrils in the sclera was examined by transmission electron microscopy (TEM).

RESULTS

Compared with the ocular axial length in wild type mice, the axial length was increased by 10% in Lum(-/-)Fmod(-/-) (P = 0.02) mice. Retinal detachment was frequent in the double-null and rare in the lumican-null animals. Compared with the wild-type sclera, the sclera in all null mutants was significantly thinner with fewer lamellae (P < 0.05). The double-null sclera contained abnormally large-diameter (120-160 nm) and small-diameter (30-60 nm) collagen fibrils, whereas the fibromodulin-null sclera was enriched for the small-diameter fibrils. The collagen fibril diameter distribution in the lumican-null sclera was similar to that of the wild-type.

CONCLUSIONS

An increase in small-diameter fibrils in the fibromodulin-null sclera suggests a key role for fibromodulin in the maturation and assembly of scleral collagen fibrils. That fibril diameter distribution in the lumican-null sclera was comparable to that in the wild type, but severely disrupted in the double null, suggests a role for lumican that is crucial in the absence of fibromodulin. The eyes of Lum(-/-)Fmod(-/-) mice show certain features of high myopia: increased axial length, thin sclera, and retinal detachment. Mutations or altered expression of these proteoglycans may contribute to myopia in humans.

Sclerochoroidal calcification associated with Gitelman syndrome

PURPOSE

To investigate sclerochoroidal calcification in a patient with Gitelman syndrome.

METHOD

Case report. Bilateral fundus abnormalities observed in a 58-year-old woman were documented with fluorescein angiography and tomodensitometry.

RESULTS

Symmetric yellow-white subretinal lesions were observed in the superotemporal midperiphery of the fundus of each eye. Tomodensitometry examination was consistent with calcium deposition. The medical history included Gitelman syndrome. Sclerochoroidal calcification probably resulted from the severe hypomagnesemia.

CONCLUSION

Gitelman syndrome may be a cause of sclerochoroidal calcification.

[Expression of CD44 molecule and its significance in uveal and conjunctival melanomas]

The aim of this study was to evaluate the role of over expression of CD44 molecule in the development and progression of uveal and conjunctival melanomas. Flow cytometry (FCM) and immunofluorescence methods were used for detecting the CD44V expression in uveal malignant melanomas (UMM), conjunctival nevi (CN) and conjunctival malignant melanomas(CMM). The expression content of CD44 in 7 cases of CMM was significantly higher than that in 5 cases of CN (P < 0.05); the CD44V positive expression percentages in 7 cases of CMM and 40 cases of UMM were 71.43% and 62.50% respectively; the expression content of CD44V in UMM was related to scleral invasion (P = 0.0105); there was a negative correlation between the expression content of CD44V and proliferative index (PI), S-phase fraction (SPF) (P < 0.01; P < 0.05). The results suggested that the over expression of CD44V might be involved in the development of CMM and UMM and related to local infiltration ability of UMM and that the CD44V expression content detected by FCM might be helpful in discriminating CN From CMM, but this waited for further research confirmation.

Tophus-like, conglomerated, crystalline calcification of the sclera

The clinical history and the pathohistological findings of a peculiar form of multifocal scleral calcification in 3 globes of 2 patients are described. It consisted of globular drusen of rod-like crystals, fusing into large, tophus-like conglomerates. The crystals consisted of monoclinic and triclinic calcium pyrophosphate. The deposits can be interpreted therefore as scleral pseudogout. They were combined in places with a diffuse, idiopathic inner scleral calcification. The pathogenesis of these mineralizations is unclear. No signs of a dystrophic calcification were present. One patient, suffering from Alport's syndrome, had been normocalcemic for the last 16 years after renal transplantation, and no disturbed calcium metabolism was known in the second case.

[Amyloidosis of the iris and sclera in the pathogenesis of glaucoma]

Morphological analysis of 173 biopsies of the iris and sclera removed during antiglaucoma operations in 115 patients with open angle glaucoma showed extracellular deposits of amyloid in 44.4% of cases, which complicated the course of glaucomatous process and had pathogenetic importance. Amyloid was identified by Congo red [correction of Congo-rot] staining with the control in the polarized light and also by toluidine blue staining for chondroitin and dermatan sulfates. The vascular and muscle (pupillary muscle) forms of amyloidosis were found in the iris and the pericollagen and focal forms in the drainage system and sclera. We propose to classify the amyloid form of glaucoma with specific morphological picture.

Sclerochoroidal calcification

We studied 19 patients with sclerochoroidal calcification. The findings were bilateral in 16 patients and unilateral in the remaining three patients. The lesions, which were usually multifocal, had two characteristic appearances, plaque-like and tumorlike. Eleven patients had relatively flat, irregularly shaped, plaque-like, yellow-white lesions located between the arcades and the equator. Eight patients had more elevated tumorlike lesions, ranging up to 6 mm in height. All showed patterns on echography consistent with calcification. The calcification was often documented in both the choroid and sclera; sometimes it appeared only in the choroid, but never only in the sclera. Calcium metabolism appeared to be normal in all but two of the nine patients in whom it was investigated. Idiopathic sclerochoroidal calcification has a characteristic echographic and ophthalmoscopic appearance and may be more common than has been realized.

Spindleform scleropathy: collagen changes of the sclera. A pathologic report

To our knowledge, this is the first pathologic report of interscleral collagen bundle changes occurring as well-defined spindleform lesions randomly interspersed within the sclera. The lesions were observed in an otherwise healthy 75-year-old man whose eye was enucleated because of a uveal malignant melanoma. There are few reports in the literature of focal scleral changes of a predominantly acid mucopolysaccharide nature. The entity we observed in this case differs from these reports by its spindleform appearance, random distribution (not overlying the melanoma) and predominantly vicinal glycol nature. Histopathologic, histochemical, and ultrastructural studies revealed that the lesions were not the result of mucoid degeneration of the scleral collagen and not an abnormal collagen structure.

Eosinophil and neutrophil degranulation in ophthalmic lesions of Wegener's granulomatosis

Although eosinophils and neutrophils have been identified in orbital and corneoscleral tissues in some patients with Wegener's granulomatosis, their role in the pathogenesis of the disorder is not completely understood. Nine specimens from six patients with Wegener's granulomatosis and autopsy controls from patients without ophthalmic disease were evaluated with indirect immunofluorescence for eosinophil granule major basic protein and neutrophil elastase. Extracellular deposition of both major basic protein and elastase was identified in orbital tissues from all the patients with Wegener's granulomatosis. Two of the specimens were from enucleated eyes with corneoscleral disease; extracellular deposition of eosinophil major basic protein was identified in one eye, and extracellular neutrophil elastase was deposited in both eyes in lesional areas. None of the control tissues showed major basic protein or elastase deposition. These findings suggest that both eosinophils and neutrophils participate in the pathogenesis of the orbital and corneoscleral manifestations of Wegener's granulomatosis.

Senile scleral plaques: a histopathologic study using energy-dispersive x-ray microanalysis

The investigators reviewed the pathologic findings of 21 senile scleral plaques in 17 enucleated globes. Eyes were fixed in formalin and routinely processed for light microscopic examination. Two representative calcified scleral plaques were subjected to energy-dispersive x-ray microanalysis. Plaques were located in the sclera just anterior to the insertion of the horizontal rectus muscles. Microscopic examination of the involved sclera disclosed a spectrum of histopathologic changes involving increased hematoxylinophilia of the scleral collagen, decreased stromal cellularity, the presence of scleral fibers with a unique corkscrew appearance, and calcium deposition. The calcified plaques contained calcium phosphate as indicated by histochemical methods and energy-dispersive x-ray microanalysis. Conjunctival elastosis was present in 12 of the 14 eyes in which sufficient conjunctiva was present for histologic evaluation. Accumulated actinic damage from solar irradiation may play a role in the pathogenesis of senile scleral plaques.