Biomedical subjects

M Savoldelli

Publications and source records attributed to M Savoldelli.

At least 73 records · Page 4Linked to original sources

PubMed1985

[Keratoglobus].

Keratoglobus is a bilateral corneal disease characterised by thinning and protrusion of the entire corneal surface. The cornea is of normal size and usually transparent. Acute corneal edema due to rupture of Descemet's membrane and perforation even from minimal trauma are the most frequent complications. Keratoglobus may be associated with blue sclera, hyperextensibility of the joints or auditory problems. Most often it is a congenital disease with autosomal recessive transmission, but it may be secondarily acquired to an advanced keratopathy (keratoconus), to trauma or to exophthalmos. We report 5 cases of keratoglobus. 4 patients underwent penetrating keratoplasty. The anatomical abnormalities of congenital keratoglobus (3 cases) are constants : an absent Bowman's membrane, a disorganized stroma containing granular material, a thickened, striated Descemet's membrane with breaks, folds and verrucosities. On the other hand, acquired keratoglobus (1 case) shows localised breaks in Bowman's membrane resembling those of keratoconus. The anatomopathological differences are discussed.

Adult↗

PubMed1985

[Schnyder's crystalline dystrophy. I. Study of a case by light and electron microscopy].

Bilateral penetrating keratoplasties were performed in a case of Schnyder's crystalline stromal dystrophy and the buttons were examined by light and electron microscopy. Staining for lipids was negative probably because they had been dissolved during the dehydrating stage of the embedding process. In electron microscopy the deposits were highly suggestive of lipids. These deposits appeared as electron-lucent spaces, either empty and of regular geometrical form suggestive of cholesterol crystals, or smaller, rounded, and containing relative electron-lucent material also believed to be lipids. The crystals randomly accumulated in the superficial stroma, in Bowman's layer and in some basal epithelial cells, and the rounded spaces could be seen in all the layers of the stroma. Bowman's layer exhibited many disruptions. The endothelium and Descemet's membrane were unaffected. Our findings are compared with previous histological and electron microscopical reports.

Cholesterol↗

PubMed1984

Keratoconus and normal cornea: a comparative study of the collagenous fibers of the corneal stroma by image analysis.

Using an automatic image analysis technique, we studied the characteristics of the collagenous fibers of the corneal stroma of keratoconus at different stages of development. The clear portions of keratoconus specimens were studied at three different levels: anterior, middle, and posterior. The parameters obtained were compared with those of a normal adult cornea with the purpose of determining which ultrastructural alterations were caused by the appearance and progression of keratoconus.

Adolescent↗

PubMed1983

[Polymorphic posterior corneal dystrophy. Histological and ultrastructural study of 2 cases].

Optical, scanning and transmission electron microscopy examinations were performed in two cases of polymorphic posterior corneal dystrophy. The first case demonstrated typical clinical features, histologic examination revealing the presence of granular deposits in the posterior stroma, and an anarchic fibrillary zone between the stroma and Descemet's membrane. The latter was thickened, with a normal striated fetal zone, an intermediate zone composed of fibrils and long and short collagen fibers, and a normal adult zone. Cells lining the anterior chamber were of the typical endothelial type. Clinical signs in the second case were less evocative even though the father of the patient presented a typical form. Histology showed similar granular deposits in the posterior stroma, and the fibrillary zone beneath Descemet's membrane, which was thickened and delaminated and composed of three layers. Anterior chamber lining cells were disposed in several layers and had numerous surface microvillosities. They were linked by many desmosomes. These cells were therefore of the epithelial type. Comparing the findings in these two cases demonstrates that whereas many common signs existed there was a fundamental difference between the cell types on the posterior surface of the cornea. A review of all possible hypotheses led to the conclusion that the epithelial type cells are of mesenchymatous origin, similar to endothelial cells, as they possess the identical property of secreting a normal adult type of Descemet's membrane and of ensuring deturgescence of the corneal stroma. The pathological mechanisms involved, probably biochemical in nature, which provoke this anomaly can be fairly precisely determined as developing during fetal life, but they remain totally inexplicable. This hypothesis of a mesenchymatous cell developing into an epithelial type allows polymorphic posterior dystrophy to be regarded as a distinct entity, with similar features to other neonatal posterior dystrophies and a vast group of endothelial dystrophies including, among others, congenital edematous dystrophy.

Adolescent↗

PubMed1983

[Sclerocornea. Ultrastructural and morphologic study].

A 6 month old white male infant had bilateral congenital diffuse sclerocornea. A penetrating keratoplasty was performed in his left eye. Histologic examination by electron microscopy demonstrated: the presence of vacuoles in the superficial epithelial layer, the absence of Bowman's membrane, a disorganization of collagen fibers and lamellae more prominent in the middle stroma, and an extremely thin Descemet's membrane. A comparison, using an automatized image analysis method, was carried out between the stroma of sclerocornea and a normal cornea. Morphometric analysis of the collagenous fibril's diameter and the interfibrillar distances demonstrated a statistically significant difference (p less than 0.001) between the two corneas examined.

Cornea↗

PubMed1983

[Morphologic and quantimetric study of the surface of the corneal epithelium].

Studies were conducted to attempt to demonstrate the presence of a twofold cell population in the superficial cells of the corneal epithelium as seen on scanning electron microscopy. Transmission electron microscopy was used to compare corneas washed with acetylcysteine with unwashed corneas after staining of surface mucosubstances with ruthenium red. Washing was found to remove some of the mucus film deposited by the tears on the epithelial surface. In contrast, both specimens showed a layer of substance, stained by the ruthenium red and more or less abundant according to the cell, which was thick enough to mask the microvillosities on scanning microscopy. Two distinct layers were observed. One of constant thickness was a thin layer which followed the outline of the microvillosities exactly but did not mask them. This was formed of glycocalix itself, a substance of cellular origin which was visible on developed cell surfaces even before desquamation of adjacent cells occurred. The other layer was more heterogeneous and attached to the cell wall, but it cannot be removed by washing with acetylcysteine. It also appeared on developed cell surfaces before adjacent cells had desquamated. The substance could arise from the lacrimal film or the necrozed remnants of superficial cells. It appears to increase in quantity with aging of the cell, and is capable of infiltrating between the microvillosities giving the appearance of dark cells on scanning microscopy. The different cells noted on scanning microscopy vary only by the amount of this mucin-like substance.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1983

[Scanning microscopy study of the corneal epithelium. Relation of various aspects to the lacrimal film].

Cells of the superficial layer of the corneal epithelium demonstrate differences in luminosity on scanning electron microscopy which has led to their classification as clear, intermediate or dark cells, differences attributed to varying amounts of surface microvillosities. Evidence is provided confirming that differences between cells is not due to artefacts during preparation or observation of specimens. On the other hand, this technique cannot demonstrate whether different evolutory stages of the same cell are involved. Scanning microscopy cannot confirm a single evolutory epithelial cell are involved. Scanning microscopy cannot confirm a single evolutory epithelial cell cycle from the position of the cell in relation to adjacent desquamating cells, or the study of the cell nuclei. Nor can a satisfactory response to the problem be supplied by studying mucosubstances deposited by the lacrimal film on the surface of the epithelium, either by optical microscopy or after scanning electron microscopy with or without washing with acetylcysteine. The presence of superficial epithelial cells of different appearances on scanning microscopy must be due to variations in the amount of glycocalix, the mucus film adsorbed onto the cell surface.

Animals↗

PubMed1981

[Gelatinous drop-like dystrophy of the cornea (primary amylosis) (author's transl)].

Two cases of gelatinous drop-like dystrophy of the cornea in young North-African (Algeria, Tunisia) subjects are reported. Clinical examination revealed characteristic subepithelial gelatinous drops in the cornea. Histology showed the amyloid nature of the subepithelial deposits, their fibrillary from being demonstrated on ultrastructural examination. Lamellar keratoplasty did not prevent recurrences. A pathogenic hypothesis is suggested involving a role of epithelial induction in the fibroblast development.

Adult↗

PubMed1980

[Fourier transformation study of corneal stroma].

The various patterns observed by generating Fourier transforms of the fixed normal corneal stroma are described. The patterns are analysed in terms of the dimensions of the stromal fibers, the dimensional and directional order of the fiber distribution and the order of the fiber-fiber functions by proteoglycans.

Collagen↗

PubMed1980

The development of the irido-corneal angle in the chick embryo.

The iridocorneal angle of the chick embryo was examined by scanning electron microscopy from the 7th day to the 19th day of development. The mesodermal tissue situated between the corneal endothelium and the iris differentiated into trabecular cells. These cells formed a strip on the 9th day and enlarged on the 13th day to form long cellular fibres. The trabecular meshwork was recognizable on the 15th day and reached full development only on the 19th day. The development of the trabecular meshwork was probably much earlier than is usually described. It began with differentiation of the corneal endothelial cells and these cells acquired a multipolar cell body with long cellular processes. The last stage is probably regulated to avoid an abnormal development of the angle structure. These results can be correlated with those obtained in the morphological examination of the structure of the angle in congenital glaucoma and the "cleavage syndrome" of the anterior chamber.

Animals↗

PubMed1980

Combined macular dystrophy and cornea guttata: an electron microscopic study.

Four cases of macular dystrophy in siblings were studied, 2 brothers and 2 sisters (49, 52, 55, 57 years old). The two youngest had an associated cornea guttata. We performed histologic, transmission, and scanning electron microscopic studies, and in addition a morphometric analysis of Descemet's membrane and of guttata excrescences. Previous studies have been confirmed and the problem of the relationship between the two conditions of macular dystrophy and guttate excrescences is emphasised.

Cornea↗

PubMed1980

[Marginal pellucid degeneration of the cornea, or marginal keratoconus (author's transl)].

Histological and ultrastructural examination of the corneas of a woman presenting with marginal pellucid degeneration, treated by bilateral perforating keratoplasty, revealed obvious analogies with keratoconus. The condition of marginal pellucid degeneration is really only an excentric keratoconus. Marginal pellucid degeneration is a rare affection but it has been clinically sell defined. Many authors seem to have recognized it under various different names (cylindrical keratoconus, corneal protusion, piriform cornea). It is a pouch-shaped deformity of the cornea overlying a thinning of the linear stroma concentric to the limbus, always inferior and bilateral, perfectly transparent, non-vascularized, and without signs of corneal of conjunctival inflammation. The affection usually occurs in young adults.

Adult↗

PubMed1980

[Epithelial invasion of the anterior chamber : exploration by scanning electron microscopy (author's transl)].

Transfixing keratoplasty was performed in a patient seven years after a lens extraction, following the appearance of corneal edema with hypertony and proliferation of a retrocorneal veil. Scanning electron microscopy examination of the posterior surface of the removed graft demonstrated the presence of a vast cellular veil formed of epithelial cells. The principal characteristics of these cells were their polygonal shape, slightly raised edges, and the presence of numerous surface microvilli. Because of the particular characteristics of this epithelium, scanning electron microscopy can be used to observe mitoses in the deep layer as well as for differentiation of the superficial layers. The epithelial cell appears to be identical, as far as its evolution is concerned, both in the aqueous humor and when in contact with the lacrymal film. When compared with other modern investigational techniques, the scanning electron microscope appears to be an effective method for studying epithelial invasion of the anterior chamber. In fact, optical microscopy is of little value in such cases, and transmitted light electron microscopy too heavy a technique for the results expected. Scanning electron microscopy enables precise definition of epithelial cells and can confirm their corneal or conjunctival origin.

Anterior Chamber↗

PubMed1979

[Familial congenital dystrophy of the corneal stroma: Turpin's syndrome (author's transl)].

In 1939, R. Turpin and al. described cases of hereditary and congenital corneal opacities in three generations of one family. The members of this family have since been followed-up regularly by the author, examination of the corneas of the grandmother and the grand'daughter made by electron microscopy, the morphology compared, and an attempt made to establish the progression of the lesion. It so happened that at the same time, witschel and al. published (June, 1978) the results of their examination of the American members of the same family. Their conclusions were the same, in that this familial congenital dystrophy of the cornea is mainly stromal and differs therefore from familial congenital endothelial dystrophies. The author's analysis is complementary to theirs.

Adult↗

PubMed1978

Ultrastructural study of the cornea in the chick embryo.

The study of the development of the cornea in the chick embryo by transmission and scanning electron microscopy allows us to observe the differences between the aspect of thin sections and the surface of the cells. When studied with the T.E.M. both endothelium and epithelium have a rather normal and mature aspects on the 9th day of development. Observed with the S.E.M., the aspect of the surface of the epithelium becomes mature no earlier than on the 19th day, whereas the development of the endothelium is completed only after hatching. The development of apical junctional complexes occurs at a later stage in the organisation of the endothelial layer.

Animals↗

PubMed1978

Reis-Bückler's dystrophy.

A case of Reis-Bückler's dystrophy in a 36-year-old man is reported. Its clinical aspect is compared with its histological and ultrastructural features. The slight reticular opacities situated superficially in the central part of the cornea, immediately beneath the epithelium, correspond to dark, irregular deposits. These replaced the basal membrane and Bowman's membrane and are composed of granular material, glycogen granules, and short fibers. These short, curved, osmiophilic fibers whose diameter is approximately 130 A are also located inside the anterior stromal lamellae. These deposits seem to be the characteristic feature of this particular and rare dystrophy, stated as by Hogan. Their nature and origin are discussed.

Adult↗

PubMed1978

Fine structure of palpebral molluscum contagiosum and its secondary conjunctival lesions.

One case of molluscum contagiosum of the lid, which has been followed by follicular conjunctivitis and superficial punctate keratitis, has enabled us to compare the ultrastructure of the skin tumor and of the conjunctival lesion. Electron microscopic observation is the only way for discovering the causal Poxvirus. Up to now isolation of the viral strain has not been possible. Examination of the skin tumor showed different maturation forms of the virus and associated cell alterations. In the conjunctiva there was an inflammatory reaction, with exocytosis and infiltration of the chorion by lymphocytes and plasma cells. Intracytoplasmic organelles were formed in the superficial epithelial cells. Their size and structure resembled that of the immature virions found in the epidermic cells. The comparison between skin and conjunctival lesions suggests the following sequence of events in the pathogenesis: the virus, leaving the lid tumor, probably penetrates the conjunctival cells and, without finding the conditions necessary for its full development, produces abnormal viral inclusions unable to become a mature virus. The excision of skin nodules thus cures the infection, since it prevents further reinfection by the skin virus. The morphological criteria on which this hypothesis is based must be confirmed by chemical and morphometrical studies.

Adolescent↗

PubMed1978

[Acute keratoconus--an ultrastructural study (author's transl)].

The corneal oedema of acute keratoconus is related to a break in endothelial-Descemetic continuity. This break was confirmed by optical and electron microscopical study of an anatomical section taken during a perforating keratoplasty; the methods of repair were studied five months after the incident. The corneal endothelium had almost totally recoversed the surfaces of the detached Descemet's membrane and the posterior surface of the bare corneal stroma. Electron microscopic study tended to indicate that the endothelial repair occurred more by cellular extension rather than mitosis (very flat cells) and showed that the inter-cellular connecting systems (focal tight junctions) were not regular, or even absent altogether, which explained the clinical finding of persistant corneal oedema. The endothelial cells secrete a Descemet neo-membrane over all their area which is more or less complete. They revover an original scarred stroma of fibrocytes of the posterior stroma.

Acute Disease↗