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Biomedical subjects

K Tervo

Publications and source records attributed to K Tervo.

47 records · Page 3Linked to original sources
PubMed1983

Substance P immunoreactivity in normal human retina and in retinoblastoma.

Substance P (SP) immunoreactivity was demonstrated using the indirect immunofluorescence technique in one normal and one retinoblastomatous human retina. In the normal retina SP immunoreaction was located in nerve fibres but not in the neurons in the inner plexiform layer. A similar location was observed in the histologically normal areas of the retinoblastoma sample. SP immunoreactive neurons, probably amacrine cells, were, however, observed in the transitional area between the normal retina and the tumour. The tumour mass, although mainly SP negative, contained clusters of pleomorphic cells with an intense SP immunoreaction. The general distribution of SP immunoreaction in human retina resembles that of other mammals. The positive SP immunoreaction in retinoblastoma cells suggests that the tumour either may have its origin in the amacrine cells or that the retinoblasts are capable of redifferentiating in the direction of the amacrine cell population. The general problems concerning the origin and pathogenesis of retinoblastoma are discussed.

Child, Preschool↗
PubMed1982

Ocular neuropeptides.

This article deals with the neuropeptides found in the eye and their actions. Substance P (SP) and VIP have been found in the anterior chamber of the eye. Here SP is localized in the sensory nerves of the sclera, cornea, iris, ciliary body and ciliary processes. It is supposed to be a sensory transmitter but can also be liberated by peripheral nerve endings as a response to various trauma. When this happens in the eye, for instance, after irritation of the Vth cranial nerve, SP causes an intense and long lasting miosis and may have some further actions as well. VIP has been demonstrated in nerves (probably cholinergic) of the posterior choroid and ciliary body. It is a potent vasodilator and may regulate choroideal blood flow. The retina is especially rich in different neuropeptides. SP, VIP, neurotensin, enkephalin, somatostatin, glucagon and gonadotropin-releasing hormone have all been demonstrated in the inner plexiform layer of the retina of various animal species. Specific information about the physiological role of retinal neuropeptides is still scarce but research is in progress. Considering the clinical significance of the new information about ocular neuropeptides, SP seems to be the most important substance. Recently a synthetic SP antagonist was reported to block the inflammatory response in the rabbit eye, which suggests a clinical use for this type of compounds.

Animals↗
PubMed1982

Substance P-immunoreactive nerves in the human cornea and iris.

Human corneas and irides obtained from corneal surgery or sector iridectomies were processed according to the indirect immunofluorescence technique for the demonstration of substance P (SP) immunofluorescence by means of a monoclonal SP antibody. SP immunofluorescence was observed in varicose fibers of the corneal epithelium and nerve trunks in the corneal stroma. SP-immunoreactive nerve fibers in the iris were detected mainly in the pupillary margin in both dilator and sphincter areas.

Cornea↗
PubMed1981

Immunoreactivity for substance P in the Gasserian ganglion, ophthalmic nerve and anterior segment of the rabbit eye.

The distribution of substance P (SP) immunofluorescence was investigated in the Gasserian ganglion, ophthalmic nerve and in the anterior segment of the rabbit eye. About one third of the nerve cell bodies in the Gasserian ganglion exhibited SP immunofluorescence, which was also observed in some nerve fibres of the ophthalmic nerve. In the cornea, some SP-positive nerves were found in the stroma and few of them were also observed in the epithelium. The iris contained numerous nerve fibres with SP immunofluorescence. In the sphincter area such fibres were circular, while the orientation of the SP fibres was radial in the dilator muscle. Both in the iris and in the ciliar body, the largest vessels are surrounded by nerves exhibiting SP immunofluorescence. A few nerve fibres also appeared in the stroma of the ciliary processes.

Animals↗
PubMed1981

Effect of prolonged and neonatal capsaicin treatments on the substance P immunoreactive nerves in the rabbit eye and spinal cord.

Substance-P (SP) immunoreactivity was demonstrated in the rabbit eye and spinal cord using monoclonal SP antibody and an indirect immunofluorescence technique. Norves containing SP immunoreactive material were found in the cornea, iris and ciliary body of which the iridic sphincter had the densest innervation. Neither prolonged subcutaneous treatment (up to 280 mg/kg) augmented by intracameral capsaicin injection nor neonatal treatment with drug 70 mg/kg eliminated this immunoreactivity, though both blocked the miotic effect of intracameral SP. It is concluded that capsaicin is not specific SP depleting agent but rather a neurotocic substance that affects noxious pathways and probably prevents the release of the SP retained by the nerve following the treatment used.

Animals↗
PubMed1978

Pre- and postnatal development of catecholamine-containing and cholinesterase-positive nerves of the rat cornea and iris.

Glyoxylic acid-induced fluorescence technique and a copper thiocholine method were used to investigate the ontogenesis of the catecholamine-containing and cholinesterase-positive nerves of the rat iris and cornea. First fluorescent nerve fibres appeared in the iris on the 18th gestation day and in the cornea on the 19th day. A rapid increase in the density of the adrenergic nerve fibres of the iris continued to the age of three weeks, while the number of such fibres were small in the cornea. Acetylcholinesterase-positive fibres appeared both in the cornea and in the iris on the 19th gestation day. Their density increased more rapidly in the iris, especially in the sphincter muscle, than in the cornea. Non-specific cholinesterase activity was localized in the Schwann cells and the reaction was more intense during development than in the nerves of the cornea of adult rats.

Acetylcholinesterase↗
PubMedDate not supplied

Release of calcitonin gene-related peptide in tears after excimer laser photorefractive keratectomy.

BACKGROUND: Sensory nerves known to affect corneal healing are damaged to a variable degree after photorefractive keratectomy (PRK). To search for nerve-bound factors involved in corneal healing, we monitored tear fluid calcitonin gene-related peptide (CGRP) levels of six human eyes undergoing PRK. METHODS: CGRP concentrations were determined using an immunoassay. RESULTS: Normal human tear fluid contains CGRP. The mean CGRP concentration was slightly increased postoperatively, despite a marked tear fluid hypersecretion. Consequently, an almost ten-fold increase in release of CGRP in tears was observed on days 1 and 2 after PRK. Values measured on day 7 had returned to a normal level. CONCLUSION: The observed postoperative increase in release of CGRP in tears may have an impact on the healing of PRK wounds. Extensive neural damage following deep photoablations may impair healing and should probably be avoided.

Acetylcholinesterase↗
PubMedDate not supplied

Corneal wound healing and nerve morphology after excimer laser in situ keratomileusis in human eyes.

BACKGROUND: Our aim was to describe wound healing and nerve regeneration in the human cornea after excimer laser in situ keratomileusis. METHODS: Excimer laser in situ keratomileusis was done in three human eyes 8 days, 54 days, and 4 months prior to enucleation. Acetylcholinesterase reaction was used to histochemically demonstrate the corneal nerves. Immunohistochemical methods were used to demonstrate the following wound healing proteins: cellular fibronectin, tenascin, transforming growth factor-beta 1, and alpha-smooth muscle actin. RESULTS: All corneas healed without complication. No epithelial hyperplasia appeared and the Bowman's layer was smooth and acellular. An epithelial plug extending up to 100-300 microns under the flap margins was seen in all specimens. Regenerative nerve fiber bundles emerging from sharply cut anterior stromal nerves were observed, but the deeper nerves were normal. Restricted expression of fibronectin and tenascin was found at the wound area. All corneal cell types were positive for transforming growth factor-beta 1 antibody. Cells lining the limbal vessels were positive for alpha-smooth muscle actin antibody whereas the corneal cells were negative. CONCLUSIONS: The nerve morphology showed only a few abnormalities, especially in deep stromal nerves. Epithelial plugs at the flap margins may maintain a delayed wound healing process for several months but otherwise the process remained active for a relatively short time.

Acetylcholinesterase↗