Ocular Cavity Research Articles

A mutation in the latency-related gene of bovine herpesvirus 1 disrupts the latency reactivation cycle in calves.

Bovine herpesvirus 1 (BHV-1) is an important pathogen of cattle, and infection is usually initiated via the ocular or nasal cavity. Following acute infection, the primary site for BHV-1 latency is the sensory neuron. Reactivation from latency occurs sporadically, resulting in virus shedding and transmission to uninfected cattle. The only abundant viral transcript expressed during latency is the latency-related (LR) RNA, suggesting that it mediates some aspect of latency. An LR mutant was constructed by inserting three stop codons near the beginning of the LR-RNA, suggesting that expression of LR proteins would be altered. The LR mutant grew with wild-type (wt) efficiency in bovine kidney cells (MDBK). When calves were infected with the LR mutant, a dramatic decrease (3 to 4 logs) in ocular, but not nasal, viral shedding occurred during acute infection relative to the wt or the LR-rescued virus (M. Inman, L. Lovato, A. Doster, and C. Jones, J. Virol. 75:8507-8515, 2001). In this study, we examined the latency reactivation cycle in calves infected with the LR mutant and compared these results to those from calves infected with wt BHV-1 or the LR-rescued virus. During acute infection, lower levels of infectious virus were detected in trigeminal ganglion homogenates from calves infected with the LR mutant. As judged by in situ hybridization, BHV-1-positive neurons were detected in trigeminal ganglia of calves infected with the wt but not the LR mutant. Although LR-RNA was detected by reverse transcription-PCR in calves latently infected with the LR mutant, a semiquantitative PCR analysis revealed that lower levels of viral DNA were present in trigeminal ganglia of calves infected with the LR mutant. Dexamethasone treatment of calves latently infected with wt BHV-1 or the LR-rescued virus, but not the LR mutant, consistently induced reactivation from latency, as judged by shedding of infectious virus from the nose or eyes and increases in BHV-1-specific antibodies. In summary, this study demonstrates that wt expression of LR gene products plays an important role in the latency reactivation cycle of BHV-1 in cattle.

A mutation in the latency-related gene of bovine herpesvirus 1 leads to impaired ocular shedding in acutely infected calves.

Bovine herpesvirus 1 (BHV-1) is an important pathogen of cattle, and infection is usually initiated in the ocular or nasal cavity. Like other alphaherpesviruses, BHV-1 establishes latency in sensory neurons but has the potential of reactivating from latency and spreading. The only abundant viral transcript expressed during latency is the latency-related (LR) RNA, which is alternatively spliced in trigeminal ganglia during acute infection (L. R. Devireddy and C. Jones, J. Virol. 72:7294-7301, 1998). LR gene products inhibit cell cycle progression (Y. Jiang, A. Hossain, M. T. Winkler, T. Holt, A. Doster, and C. Jones, J. Virol. 72:8133-8142, 1998) and chemically induced apoptosis (J. Ciacci-Zannela, M. Stone, G. Henderson, and C. Jones. J. Virol. 73:9734-9740, 1999). Although these studies suggest that LR gene products play an important role in the latency/pathogenesis of BHV-1, construction of a mutant is necessary to test this hypothesis. Because the bICP0 gene overlaps and is antisense to the LR gene, it was necessary to mutate the LR gene without altering bICP0 expression. This was accomplished by inserting three stop codons near the beginning of the LR RNA, thus interfering with expression of proteins expressed by the LR RNA. The LR mutant virus grew with wild-type (WT) efficiency in bovine kidney (MDBK) cells and expressed bICP0 at least as efficiently as WT BHV-1 or the LR rescued virus. When calves were infected with the LR mutant, we observed a dramatic decrease (3 to 4 log units) in ocular shedding during acute infection relative to WT or the LR rescued virus. In contrast, shedding of the LR mutant from the nasal cavity was not significantly different from that of the WT or the LR rescued virus. Calves infected with the LR mutant exhibited mild clinical symptoms, but they seroconverted. Neutralizing antibody titers were lower in calves infected with the LR mutant, confirming reduced growth. In summary, this study suggests that an LR protein promotes ocular shedding during acute infection of calves.

First description of the male and redescription of the female of Philometra salgadoi Vidal-Martínez et al., 1995 (Nematoda: Philometridae) from the ocular cavity of the marine fish Epinephelus morio in Mexico.

A redescription of the female and the first description of the male of the philometrid nematode Philomnetra salgadoi Vidal-Martínez, Aguirre-Macedo et Moravec, 1995 are presented on the basis of specimens collected from the type host, the red grouper. Epinephelus morio (Valenciennes; Pisces: Serranidae), in the Gulf of Mexico off the northern coast of Yucatan, Mexico. The morphology of this species is compared with that of related congeneric species.

Blind Spots and Afterimages: The Narrative Optics of Claude Simon’s Triptyque

Blind Orion Tu sembles privilegier de plus en plus l'image, la description. [...] Il y aurait donc une sorte de coincidence entre percevoir et ecrire? (1) To the question posed above by Lucien Dallenbach, Claude Simon answers in the affirmative, suggesting that the writing process for him has as much to do with visual perception as with its absence, the tatonnement[...] a l'aveugle of a blind Orion. In fact, Simon ends Orion aveugle with a vivid evocation of visual perception: the drawing of an eye accompanied by the description of images sliding onto the retinal membrane. In a sense, the image seems to identify perceptual immediacy as the horizon toward which the Simonian text leans. (2) But this particular representation of the organ of vision also warrants closer attention within the context of optical science, for no simple definition of visual perception--as immediate, subjective, or nonnarrative--can adequately define its role in Simon's novels. On the penultimate page of Orion aveugle the reader encounters the full-color anatomical plate depicting a human head in profile. [Fig. 1]. The head's skin has been peeled away to reveal the thick crossings of banded muscle connecting cranial lobe to jaw, chin to esophagus, ear to chest. The bone structure of sockets and lobes emerges, livid, from among the striated bands of red muscle and disappears again into the folds of white flesh at the man's shoulders and chest. The head tilts slightly to the left, a large flap of excised muscle hanging forward off the bridge of its nose, partly detached from the eye socket beneath it. And from the dark hollow of the ocular cavity stares the globular form of an eyeball, connected by whitish nerves to the bone mass surrounding it. A point of light on the eyeball's pupil makes it seem active and alive, as though the man were gazing out from behind his excoriated flesh. According to Simon's notes, this anatomical image comes from an engraving round in an eighteenth-century scientific manual; its title, Tete d'homme--document tire de `Myologie complete en couleurs et grandeur naturelle' de Jacques Gautier d'Agoty, grounds the gruesome image in the neutralizing discourse of science. In keeping with the abstracting, objectifying nature of scientific presentation, the engraving labels various body parts with small, precisely typeset letters and numerals--a's and b's around the eye, a lower-case g on the ear and an upper-case G on the lips, small numbers on the bands of muscle. But the diagram's classificatory abstraction is challenged by its vivid bodilyness. In the color reproduction, the muscles appear a bloody red against the pink-white tones of skin and bones, the shoulder looks like an amputated stump, and the set of the eyes and the mouth give the head a troubling expression that evokes a living human subject rather than a neutral anatomical model. [FIGURE 1 OMITTED] The engraving's uncanny juxtaposition of living tissue with textbook notation finds its counterpart in the textual description that ends Orion aveugle. Une coupe longitudinale de la tete de profile permit de void les principium organs, la masse ivories due cereal injecte de sang don't les circonvolutions compliquees battent a chaque afflux, la langue violette, les dents, les os poreux et la boule exorbitee de l'oeil, livide, enserree par ses racines rouges, avec son iris, son cristallin, son corps vitreux, et la mince membrane de sa retine sur laquelle les images du monde viennent se plaquer, glisser, l'une prenant la place de l'autre. (3) While evoking a bulging, bloody mass of bodily tissue, the passage also uses precise anatomical terms to describe the components of the eye's mechanism: iris, lens, vitreous body, retina--terms from the field of physiological optics that divide the organ according toits various abstracted functions. There is, in this description, a striking conjunction of living flow (of blood, of images coming to rest on the retinal surface) with the necessary lifelessness of a severed head. …

Philometra (Ranjhinema) salgadoi n. sp. (Nematoda: Philometridae) from the Ocular Cavity of the Red Grouper Epinephelus morio (Pisces: Serranidae) from the Yucatan Peninsula, Mexico

A new nematode species, Philometra (Ranjhinema) salgadoi n. sp., is described from females found in the ocular cavity of the red grouper (Epinephelus morio) from the Mexican coast of the Gulf of Mexico (type locality Telchac, Yucatán). The nematode is characterized by the presence of 8 conspicuously large, crescent-shaped, fleshy cephalic papillae of the external circle and 2 small, subterminal papilla-like projections on the caudal end. Another philometrid species, Philometroides belousae n. sp., is established by indication for P. parasiluri (Yamaguti, 1935) sensu Ermolenko, 1984; its adult females are parasitic in the subcutaneous tissues of Percottus glehni in the Russian Far East.

Larval and adult eyes in Capitella spec. I (Annelida, Polychaeta).

Larval and adult eyes of the capitellid Capitella spec. I have been investigated by electron microscopy. Developing larvae possess one pair of eyespots. Each eyespot is composed of one sensory cell, one pigment cell, and one supporting cell. The sensory cell bears a photosensory apparatus, an array of parallel microvilli containing a striking form of submicrovillar cisternae (SMC). A single basal body was observed near the basal end of the SMC only in 3-4-day-old larvae. This basal body was not observed in older larvae. A special, thus far unreported feature of the pigment cell is a ring of microvilli-like structures that project from the edge of the pigment cup and form a kind of diaphragm around the head of the sensory cell. Each of these microvilli-like structures is covered with closely packed rows of tiny plates, giving them a fimbriated appearance. After metamorphosis, the larval eyespots are reduced. Adult specimens possess one pair of eyes. In juvenile worms the eye is built of 2-3 pigment cells and one sensory cell. The volume of adult eyes increases by the addition of 2-3 sensory cells. The pigment cells are deposited one upon the other, wrapping the sensory complex in the center. Each sensory cell forms a deep depression at its apical end where up to three cilia and numerous microvilli arise. The sensory processes project into a common ocular cavity. Long microvilli of the uppermost pigment cells project into an extracellular channel that reaches from the ocular cavity up to the cuticle. A single fourth sensory cell of identical structure may occur next to the eye directly beneath the cuticle and close to the opening of the ocular channel. Signs of progressive disintegration of the pigment cells can be observed in adult specimens. Sensory cells are not affected by this reduction process. Eyes resembling those of Capitella spec. I have never been reported before. Their functional qualities are discussed. © 1993 Wiley-Liss, Inc.

Development and differentiation of the eye in Platynereis dumerilii (Annelida, Polychaeta).

The nereid polychaete, Platynereis dumerilii, possess two pairs of post-trochophoral eyes with one vitreous body each. The development of these eyes has first been observed in 2-day-old larvae. Whether the eye anlagen arise from stem cells or from undifferentiated ectodermal tissue was not determined. At first, the anlagen of the anterior and the posterior eyes adjoin each other. They separate in late 3-day-old larvae. The first separated eye complexes consist each of two supporting and two sensory cells. The supporting cells synthesize two different kinds of granules, the pigment granules of the pigment cup and the prospective tubules of the vitreous body. These tubules accumulate in the distal process of the supporting cell. The vitreous body is formed by compartments of the supporting cells filled with the osmiophilic vitreous body tubules. The short, bulbar photosensory processes bear microvilli that emerge into the ocular cavity. At the apex of each sensory cell process, a single cilium (or occasionally two) arises. The sensory cells contain a different kind of pigment granule within their necks at the level of the pigment cup. The rate of eye development and differentiation varies. New supporting cells are added to the rim of the eye cup. They contribute to the periphery of the vitreous body like onion skins, and sensory cells move between supporting cells. The older the individual compartments of the vitreous body are, the more densely packed is their content of vitreous body tubules. Elongation of the sensory and supporting cell processes of the older cells increases the volume of the eye. The eyespots of the trochophore are briefly described as of the two-celled rhabdomeric type with a single basal body with ciliary rootlet.

Etude infrastructurale des organes photorécepteurs chez les larves de deux Syllidiens (Annélides, Polychètes)

The ultrastructure of the larval eyes of two Syllidae: Syllis amica (subfamily: Syllinae) and Odontosyllis ctenostoma (subfamily: Eusyllinae) were studied. These eyes are composed of a pigmented supportive cell and one or two sensory cells. A dense body, corresponding to a secreted lens, can be observed in the ocular cavity formed by the supportive cell. Such a structure present in O. ctenostoma adult eyes has never been described in S. amica adult eyes.

Hereditary microphthalmos associated with ichthyosis. A genetic, clinical, ultrasonographic and histological study.

The authors report 3 cases of familial microphthalmos associated in 2 cases with ichthyosis and in another with deafness. The presence in 2 cases of epibulbar cysts echographically documented leads us to a discussion on the type of microphthalmos observed, as well as on the dependence of cysts of the ocular cavity.

COMPARATIVE AND TOPOGRAPHICAL ANATOMY OF THE FOWL : LI. PERIPHERAL COURSE OF THE OLFACTORY NERVE IN THE FOWL

The amnatomy of tlae distribution of the N. olfactorius in the fowl is described andillustrated in detail on the basis of studies on 8 complete cases of macroscopical dis-section and 9 cases of microscopical observation. Ilistological materials were fixed inBouins fluid, 100% alcohol, or 50% pyridin. They were treated by the Bielschowskyor Cajal silver impregnation methods, and made to paraffiun sections 2Os30 p thickness.The nomenclatures of the N. olfactorius given in literature on the bird are discussedat full length. The following findings warrant emphasis.The N. olfactorius arises with about 30 fine rootlets at the rostral end of the Bulbusolfactorius, and runs into the ocular cavity passing through the Foramen (nervi) olfac-torii. It then runs forward along the dorsal edge of the orbital septum. At the levelof the caudal pole of the nasal bone, the N. olfactorius divides into two branches (Figs. 1, 2), which are named he Rami interni and Rami externi (Figs. 2, 4). The formerruns ventrolaterally into the posterior turbinate bone (Figs. 4, 5, 6) and finally dividesinto filaments, which are distributed over the dorsal mucosal surface of the turbinateprocess.The latter runs forward into the dorsal wall of the posterior turbinate bone (Figs. 4, 6), and is distributed oxzer the dorsal mucous membrane of the turbinate bone, dividinginto filaments.Neither the N. terminalis nor the nasoxromeral organ, or Jacobsons organ, is foundin the adult fowl. This result is the same as already mentioned in literature.

The pathway between hyaloid blood and retinal neurons in the toad. Structural observations and permeability to tracer substances.

The hyaloid vessels form a capillary network on the inner surface of the retina. These capillaries are embedded in the vitreous humor, and they lack a glial investment. The intercellular spaces of the retina communicate with the ocular cavity, as can be evidenced by following the penetration of tracer substances. Hence, there is an extracellular diffusion pathway between hyaloid capillaries and retinal neurons, without interposition of glial cells. Trypan blue and ferrocyanide were not detected within the vitreous humor nor the retina after systemic injection. To this extent, at least, the hyaloid capillaries functionally resemble central nervous system capillaries. Intravascular injections of horseradish peroxidase established the absence of vesicular transfer across the endothelium of the hyaloid capillaries. In addition, quintuple-layered junctions between endothelial cells prevented the intercellular passage of the enzyme. It is likely, therefore, that the only pathway across the endothelium of the hyaloid capillaries is through the plasmalemma of the endothelial cells.