Gangliosides and neurotrophic growth factors in the retina. Molecular interactions and applications as neuroprotective agents.

Polypeptide growth factors and gangliosides can both be considered as trophic agents involved in almost all stages of neural cell development, differentiation, survival, and pathology. In most cases their physiological roles are still not clear due to the considerable complexity in their regulation. Several growth factors [e.

Normal retina releases a diffusible factor stimulating cone survival in the retinal degeneration mouse.

The role of cellular interactions in the mechanism of secondary cone photoreceptor degeneration in inherited retinal degenerations in which the mutation specifically affects rod photoreceptors was studied. We developed an organ culture model of whole retinas from 5-week-old mice carrying the retinal degeneration mutation, which at this age contain few remaining rods and numerous surviving cones cocultured with primary cultures of mixed cells from postnatal day 8 normal-sighted mice (C57BL/6) retinas or retinal explants from normal (C57BL/6) or dystrophic (C3H/He) 5-week-old mice. After 7 days, the numbers of residual cone photoreceptors were quantified after specific peanut lectin or anti-arrestin antibody labeling by using an unbiased stereological approach.

Excitotoxic damage of retinal glial cells depends upon normal neuron-glial interactions.

Glutamate, the principal retinal neurotransmitter, can also act as a toxin when present in excessive concentrations as may occur in pathologies such as retinal ischemia or more generally in cerebral neuronal degenerative disease. As glial cells play pivotal roles in transfer of blood-borne molecules and in glutamate clearance, we investigated the effects of the excitatory amino acids glutamic and kainic acid on different in vitro preparations of retinal Müller glial cells. Glial viability or morphology were not influenced by excitatory amino acid exposure in either pure glial cultures or in monolayer cultures of mixed neonatal neurons and glia, whereas kainic acid specifically lysed amacrine cells in mixed or pure neuronal cultures.

Growth factors and gangliosides as neuroprotective agents in excitotoxicity and ischemia.

1. At least two different groups of molecules can be considered neurotrophic factors because they exert a variety of effects upon neural cells. The first consists of the numerous families of polypeptide growth factors known to take part in almost all stages of neural cell growth and functioning, including development, differentiation, survival and pathology.

Peptide growth factors but not ganglioside protect against excitotoxicity in rat retinal neurons in vitro.

Glutamate is the major excitatory neurotransmitter in the retina, but excessive stimulation of its receptors leads to widespread neuronal stress and death. Both growth factors and gangliosides display important influences on responses to neuronal injury and degeneration. In this study, we have investigated the potential protective effects of two well characterized growth factors, epidermal and basic fibroblast growth factor (EGF and bFGF respectively), and the monosialoganglioside GM1, on cultured rat retinal neurons submitted to toxic levels of excitatory amino acids.

Radiolucent pancreatic lithiasis: a precursor stage for calcified pancreatic lithiasis or a new entity?

Objective: Radiolucent pancreatic lithiasis (RPL) has been identified as a different entity from calcified pancreatic lithiasis. The purpose of this study is to evaluate the frequency, characteristics and evolution of RPL.

Patients: Between 1983 and 1995, 278 consecutive patients who presented with pancreatic lithiasis were studied.

Channel-forming leucotoxins from Staphylococcus aureus cause severe inflammatory reactions in a rabbit eye model.

Panton-Valentine leucocidin arises from the combination of one S component (LukS-PV) with one F component (LukF-PV), whereas gamma-haemolysin comprises two S components (HlgA and HlgC) with one F component HlgB. The intravitreal injection of rabbit eye with the six combinations (S + F) of channel-forming leucotoxins produced by Staphylococcus aureus ATCC 49775 induced acute inflammatory reactions depending on time and doses of toxins. These reactions involved posterior chamber as well as anterior chamber and conjunctiva, eyelids and annexes.

Intravitreal injection of ganglioside GM1 after ischemia reduces retinal damage in rats.

Background And Purpose: Gangliosides are normal components of cell membranes and contribute to structural rigidity and membrane function. They have been shown to protect against various insults in the brain. We have shown previously that GM1 administered intraperitoneally before the induction of retinal ischemia provides a protective effect.

Ganglioside and neurotrophic growth factor interactions in retinal neuronal and glial cells.

Ganglioside (GG) and neurotrophic growth factor (GF) interactions in retinal neuronal and glial cells have been very little studied. Rat retinas were mechanically separated into outer (photoreceptor or PR) and inner (other neurons, IR) halves by planar vibratome sectioning and retinal Müller glial (RMG) cells were isolated and cultured according to previously published methods. The distribution on a percent molar basis of individual GG was different between the two halves: PR were dominated by GD3 (48% total GG) and contained only trace amounts (< 4%) of complex species (GT1b, GQ); IR was more typical of mature brain tissue, exhibiting substantial amounts (approximately 25%) of more complex GG.

Photoreceptor transplants increase host cone survival in the retinal degeneration (rd) mouse.

Retinal transplants offer a potentially interesting approach to treating human retinal degenerations, but so far little quantitative data are available on possible beneficial effects. We isolated photoreceptor layers from normal-sighted mice and grafted them into the subretinal space of retinal degeneration (rd) mice lacking rod photoreceptors. At 2 weeks after surgery, the numbers of residual host cone photoreceptors outside the graft zone were quantified following specific labelling.

Pancreatic ductal changes in HIV-infected patients.

Background: AIDS-related sclerosing cholangitis occurs in patients with advanced immunodeficiency, but ductal pancreatic alterations have not been evaluated in large series.

Methods: Twenty-nine consecutive patients with a mean age of 33 years underwent ERCP for biliary work-up. Complete pancreatography was obtained in 28 patients.

Survival and regeneration of adult human and other mammalian photoreceptors in culture.

Purpose: Fully mature neurons of central nervous system origin generally are considered unable to survive for extended periods of time in simple culture conditions. The authors report that adult and aged human, porcine, and rodent retinal neurons, including rod and cone photoreceptors, constitute an exception to this idea.

Methods: Cells were dissociated from human postmortem retinas, adult mammalian retinas, and selected brain regions and were seeded into tissue culture plates and left to develop as monolayer cultures for up to 2 months.

Endoscopic ultrasonographic diagnosis of pancreatic cancer complicating chronic pancreatitis.

Background And Study Aims: Pancreatic cancer is a rare complication of chronic pancreatitis (CP), and its diagnosis remains difficult. The present study attempted to evaluate the ability of endoscopic ultrasonography (EUS) to diagnose pancreatic masses associated with CP and provide evidence of malignancy in patients with a pancreatic mass on EUS.

Patients And Methods: Between 1991 and 1994, EUS examinations yielded a diagnosis of CP in 85 patients at our institution.

Human Usher 1B/mouse shaker-1: the retinal phenotype discrepancy explained by the presence/absence of myosin VIIA in the photoreceptor cells.

Usher syndrome type 1 (USH1) associates severe congenital deafness, vestibular dysfunction and progressive retinitis pigmentosa leading to blindness. The gene encoding myosin VIIA is responsible for USH1B. Mutations in the murine orthologous gene lead to the shaker-1 phenotype, which manifests cochlear and vestibular dysfunction, without any retinal defect.

Immunohistochemical detection of hepatitis C virus related C100-3 and core antigens in formalin-fixed liver tissue.

HCV C100-3 non-structural and core proteins have been detected by immunohistochemical methods on paraffin-embedded tissue sections using monoclonal antibodies in 22 cases of chronic hepatitis C. C100-3 protein was detected in cytoplasm and nuclei of hepatocytes whereas core protein was only detected in nuclei. The specificity of the nuclear localization of HCV antigens was discussed in relation to cross-reactivity of the anti core antibody with host-derived GOR antigen.

[Medical and endoscopic treatment of chronic pancreatitis].

Analgesics and pancreatic extracts are required for the management of pancreatic pain. The use of pancreatic enzymes supplements is necessary for the management of pancreatic insufficiency. Patients with diabetes should be treated with insulin since endogenous insulin secretion is decreased.

[Retinal grafts: biological problems and clinical stakes].

Retinal transplantation, formerly perceived as unrealistic, has become over the past decade a major clinical and biological undertaking in several laboratories and eye clinics. We describe the insights gained through the pioneering experimental works of Del Cerro et al, Turner et al, Gouras et al, Aramant et al, Lund et al e.g.

Two forms of hereditary chronic pancreatitis.

We report 11 families of hereditary pancreatitis characterized by the presence of calculi in pancreatic ducts. These were classified as (1) calcic lithiasis (one family with five cases), in which the calculi are composed of >95% calcium salts; and (2) protein lithiasis in 10 families, in which the calculi are composed of degraded amorphous residues of lithostathine, the pancreatic secretory protein that inhibits calcium salt crystallization. In both forms, transmission appears to be dominant.