Serotonin protects C6 glioma cells from glutamate toxicity.

It was recently shown that addition of L-glutamate in millimolar amounts to a culture of C6 glioma cells induced cell death within 24 h. The mechanism for glutamate toxicity in the C6 glioma cells is linked to the inhibition of cystine uptake, leading to glutathione depletion through the cystine/glutamate antiporter (Xc) system. In the present study, neurotransmitters, whose receptors were localized on the glioma (glial) cells, were evaluated for their ability to protect C6 cells from glutamate toxicity through this amino acid antiporter.

Double-staining of horizontal and amacrine cells by intracellular injection with lucifer yellow and biocytin in carp retina.

Horizontal and amacrine cells in the isolated carp retina were impaled with micropipette electrode, identified by their characteristic light responses, and injected iontophoretically with markers for morphological study. Both Lucifer Yellow CH and biocytin were injected simultaneously. Lucifer Yellow was seen by its own fluorescence while biocytin was visualized by binding with Texas Red-linked or horseradish peroxidase-conjugated avidin.

Immunohistochemical expression of human chorionic gonadotropin and P-glycoprotein in human pituitary glands and craniopharyngiomas.

In order to clarify the cellular origin of craniopharyngiomas, the authors examined the distribution of P-glycoprotein (PGP) and human chorionic gonadotropin (HCG) in five normal adenohypophyses and in 23 craniopharyngiomas using peroxidase immunohistochemistry. The correlation between the expression of PGP in craniopharyngiomas and the recurrence of these tumors was also investigated. A number of pars intermedia cyst-lining cells immunostained positively for anti-PGP antibodies.

Fibroblast growth factor induces proliferating cell nuclear antigen-immunoreactive cells in goldfish retina.

New rod photoreceptors are added to mature teleost retinas throughout life by regulated proliferation of rod precursor cells (RPCs). In this study, candidate regulators of RPC proliferation, acidic and basic fibroblast growth factors (aFGF and bFGF; 0.1 microgram/eye), interleukin-6 (IL-6; 0.

Effects of high-dose chemotherapy with syngeneic bone marrow transplantation in experimental brain tumor in rats.

Background: The clinical dose of 3-[(4-amino-2-methyl-5-pyrimidinyl)methyl]-1-(2-chloroethyl)-1-nitro- sourea hydrochloride (ACNU) is limited by the bone marrow suppression it produces. The authors investigated whether bone marrow transplantation (BMT) associated with a high dose of ACNU could alleviate marrow toxicity and achieve greater antitumor effects in Fischer rats.

Methods And Results: High doses of ACNU (20, 25, and 30 mg/kg) were administered on day 1, followed by injection of syngeneic bone marrow cells on day 3.

Expression of cell adhesion molecule E-cadherin in human arachnoid villi.

Calcium-dependent epithelial cell adhesion molecules designated as E-cadherin (also known as uvomorulin or L-CAM) were identified in human arachnoid villi by immunoblotting and immunocytochemical analyses using a monoclonal antibody HECD-1 raised against human mammary carcinoma MCF-7 cells. Immunoblot analysis showed that HECD-1 recognizes E-cadherin with a molecular weight of 124 kD. In all arachnoid cells of an arachnoid villus, E-cadherin was detected by immunolight microscopy within the cytoplasm rather than the cellular boundaries as seen in the control group.

An immunohistochemical study of regenerating newt retinas.

Light-microscopical examination was carried out to investigate the emergence and development of several classes of immunoreactive cells in regenerating retinas of the adult newt (Triturus pyrrhogaster) after total retinal ablation. Immunoreactive proliferating cell nuclear antigen (ir-PCNA, a marker for replicating cells) was present in nuclei of all neuroblasts in the early mono-layered to several-layered stages (15-20 days after retinal ablation; days 15-20), but was lost progressively in an intermediate-to-central/peripheral order as cells and layers increased (days 20-25). Cells, which had lost ir-PCNA, began to separate to form the outer nuclear, inner nuclear and ganglion cell layers around days 25-30 (the cell separation stage).

Dendritic morphology of interstitial amacrine cells with monostratified dendrites in different-sized carp retinas.

The dendritic morphology of a class of interstitial (IS) amacrine cells in retinas of different-sized carp (body length, 9.1-32.3 cm) was investigated by identifying their fluorescent nuclei pre-loaded with 4,6-diamidino-2-phenylindole (DAPI), followed by iontophoretic injection of Lucifer yellow (LY) in isolated and formaldehyde-fixed flat-mounts under microscopic control.

Immunohistochemical localization of cell adhesion molecule epithelial cadherin in human arachnoid villi and meningiomas.

Cadherins are a family of intercellular glycoproteins responsible for calcium-dependent cell adhesion and are currently divided into four types: epithelial (E), neuronal (N), placental (P), and vascular (V). Since cadherins are known to be indispensable for not only morphogenesis in the embryo but also maintenance of tumor cell nest, we examined the expression of E-cadherin in 31 meningiomas (11 syncytial, 12 transitional, 8 fibroblastic) and 3 arachnoid villi by immunoblot and immunohistochemical analyses. In the immunoblot analysis, E-cadherin was detected at the main band of Mr 124,000 in all of the arachnoid villi, as well as syncytial and transitional types of meningiomas, but not in the fibroblastic type.

Induction of proliferating cell nuclear antigen (PCNA)-immunoreactive cells in goldfish retina following intravitreal injection with 6-hydroxydopamine.

1. The dopaminergic neurotoxin, 6-hydroxydopamine (6-OHDA), was injected intravitreally into the eyes of juvenile (5- to 6-cm) goldfish. 2.

Induction of immunoreactive proliferating cell nuclear antigen (PCNA) in goldfish retina following intravitreal injection with tunicamycin.

Effects of a photoreceptor-specific biotoxin, tunicamycin (TM), injected intravitreally into the goldfish eye at one side, were explored on electroretinograms (ERGs) and proliferating cell nuclear antigen-immunoreactive (PCNA-ir) nuclei, representing the mitotic activity of rod precursors, in the retina at both sides. The eye-cup preparations were made for ERG recording, and the retinas were isolated and processed as cryosections or wholemounts by a routine immunohistochemical method for visinin (cones), opsin (rods), tyrosine hydroxylase (dopaminergic cells) and proliferating cell nuclear antigen (PCNA), at various intervals after intravitreal injection with TM (1.0 micrograms/eye).

Immunohistochemical study of erythropoietin in cerebellar hemangioblastomas associated with secondary polycythemia.

Although cerebellar hemangioblastomas are known to be associated with secondary polycythemia, the cellular derivation of erythropoietin (EPO) in hemangioblastomas still remains obscure. Specimens from 18 patients with cerebellar hemangioblastomas were immunohistochemically studied using anti-EPO monoclonal antibody. Eight cases of brain tumors, including 2 meningiomas, 2 medulloblastomas, 2 glioblastomas, and 2 metastatic brain tumors were studied as controls.

Dendritic morphology of a class of interstitial and normally placed amacrine cells revealed by intracellular Lucifer yellow injection in carp retina.

The dendritic morphology of a class of interstitial amacrine (ISA) and normally placed amacrine cells was investigated in carp retina. We first identified their fluorescent nuclei after preloading with 4,6-diamidino-2-phenylindole (DAPI) in living or aldehyde-fixed retinal wholemounts and then injected them iontophoretically with Lucifer Yellow (LY) under microscopic control. Although DAPI appeared to be accumulated nonspecifically by amacrine and ganglion cells, ISA cell nuclei were discriminated by focusing between the amacrine and ganglion cell layers.

Radiation necrosis of the optic chiasm, optic tract, hypothalamus, and upper pons after radiotherapy for pituitary adenoma, detected by gadolinium-enhanced, T1-weighted magnetic resonance imaging: case report.

A 26-year-old woman was treated for a prolactin secreting pituitary adenoma by surgery and radiotherapy (5860 rads). Fourteen months later, she developed right hemiparesis and dysarthria. A T1-weighted magnetic resonance imaging scan using gadolinium contrast showed a small, enhanced lesion in the upper pons.

Early histogenesis of the teleostean retina: studies using a novel immunochemical marker, proliferating cell nuclear antigen (PCNA/cyclin).

Immunoreactive proliferating cell nuclear antigen or cyclin (ir-PCNA), detected by immunofluorescence using a human autoantibody, was used as a marker for proliferating neuroblasts during early development of the teleostean retina. In a killifish (Medaka) and a cyprinid (goldfish), ir-PCNA was present in all retinal cells at the monolayer stage (embryonic day 2 in Medaka, days 3-4 in goldfish). Subsequently ir-PCNA was lost, as neuroblasts became postmitotic in a centre-to-periphery and proximal-to-distal (ganglion cells first, photoreceptors last) sequence.

Emergence and development of immunoreactive cells in teleostean retinas during the perinatal period.

We have used light-microscopical immunohistochemistry to investigate developmental changes of several neurochemical indicators in retinas of perinatal killifish and goldfish. Immunoreactive proliferating cell nuclear antigen (ir-PCNA/cyclin, a marker for replicating cells) was present in nuclei of all neuroblasts in the early monolayer stage, but was lost progressively in central-to-peripheral and proximal-to-distal order as the layers and cells of the mature retina appeared. The loss of ir-PCNA was slightly prior to the appearance of ir-TH (tyrosine hydroxylase), GAD (glutamic acid decarboxylase) and GS (glutamine synthetase) at the 4th embryonic day (E4) in both fish.

An ultrastructural and immunohistochemical study of extracellular matrix in meningiomas.

Extracellular matrix of meningiomas was studied by light and electron microscopy with the aid of immunohistochemical techniques. Special attention was paid to the distribution of type I, III, IV, V collagens and laminin with a comparison between meningothelial and fibroblastic types. Connective tissue fibers and basement membrane were not found among the tumor cells in the meningothelial type, but were found in the fibroblastic type.

Dopamine release via protein kinase C activation in the fish retina.

Calcium-dependent phospholipid-sensitive protein kinase [protein kinase C (PKC)] was partially purified from the carp (Cyprinus carpio) retina through DE 52 ion exchange and Cellulofine gel filtration chromatography. The phorbol ester 12-O-tetradecanoylphorbol 13-acetate (TPA) activated PKC in the nanomolar range. A major 38-kDa protein in the retinal supernatants (105,000 g) was phosphorylated in vitro by PKC during a short period (3 min).

Neurotoxicity of local administration of two nitrosoureas in malignant gliomas.

The neurotoxicity of local administration of nitrosoureas in malignant gliomas was investigated clinicopathologically. Twenty patients were entered into this study: 13 were treated with 1-(4-amino-2-methyl-5-pyrimidinyl)methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU) and 7 with methyl 6-[3-(2-chloroethyl-3-nitrosoureido]-6-deoxy-alpha-D-glucopyranoside (MCNU). On the average, a single dose of 20 mg of ACNU was administered 15 times, for a total dose of 295 mg in each case, while a single dose of 11 mg of MCNU was given 2 times, for a total dose of 24 mg.

Sequential course of uptake of intravitreal 5,7-dihydroxytryptamine by carp retinal cells.

The sequential course of uptake by retinal cells of intravitreally injected 5,7-dihydroxytryptamine (5,7-DHT) together with dopamine (DA) was investigated in juvenile carp retinas, which were removed at various intervals (1-24 h) after injection. The cells taken up 5,7-DHT were visualized immunohistochemically with anti-serotonin (5-HT) antibody and FITC-conjugated IgG. After a mixture of 5,7-DHT and DA (2.

Histological, ultrastructural and chromatographical discrimination of phospholipids in meningiomas.

Phospholipids in meningiomas were studied by light and electron microscopy, and by high-performance liquid chromatography. They were microscopically demonstrated in six of the ten cases by Sudan III staining after the fixation with potassium dichromate. However, the conventional ultrastructural fixation with glutaraldehyde and osmium tetroxide failed to confirm phospholipids, as most of them were dissolved during dehydration.

Neurotoxic effects of L-alpha-aminoadipic acid on the carp retina: a long term observation.

The hypothesis has been tested that the enantiomers of alpha-aminoadipic acid have different target effects; the L-isomer has both glio- and neurotoxic actions, while the DL-isomer has a gliospecific action in the CNS. Electrophysiological and morphological studies were carried out on the retina of the carp (Cyprinus carpio) for one to two months after intraocular injection with alpha-aminoadipic acids at various doses. Intracellular recording from horizontal cells and extracellular recording of spike discharges from ganglion cells in isolated retinal preparations were made from control and pretreated retinas at various intervals after intraocular injection with the enantiomers.

Gliotoxic effects of alpha-aminoadipic acid isomers on the carp retina: a long term observation.

The glutamate analogue, alpha-aminoadipic acid was intravitreally administered in the D-, DL- and L-forms to carp (Cyprinus carpio) retina in vivo. To make a quantitative assessment of its gliotoxic action, the activity of glutamine synthetase, whose localization was confirmed in glial Müller cells by an immunohistochemical technique, was examined at various intervals over one month. Intravitreal injection of 8 mumol alpha-aminoadipic acids reduced the glutamine synthetase activity within 4 h and maximally by 24 h.