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Biomedical subjects

K Kristensson

Publications and source records attributed to K Kristensson.

At least 199 records · Page 11Linked to original sources
PubMed1981

Peripheral nerve repair.

The neuron is remarkable as a cell with a prolonged process, the axon. Various substances and organelles are transported up and down the axon. Axotomy profoundly affects this axonal transport. The proximal stump of the axon seals off and organelles accumulate. Terminal sprouts appear and move towards the distal stump. Soon after reinnervation neurotransmission reappears. Initially polyneuronal innervation occurs but this is then eliminated. Somatopetal axonal transport has been studied using tracer macromolecules in the mouse facial neuron model. Transport was blocked by axotomy from terminals in muscle but persisted at the injured axonal membrane. This stopped when the axonal membrane grew over the stump. Transport returned after reinnervation. Such transport may carry the signals that govern neuronal response to axotomy.

Animals↗
PubMed1980

Cytophotometric quantification of retrograde axonal transport of a fluorescent tracer (primuline) in mouse facial neurons.

A method for cytophotometric quantifications of retrograde axonal transport of a fluorescent tracer in tissue sections is described. As a fluorescent tracer the anionic vital stain primuline proved to be suitable since it resulted in a strong yellow-green fluorescence, which faded very slowly permitting localization of cells during illumination with UV-light. Primuline injected into the muscles of the vibrissae in mice was transported to the corresponding nerve cell bodies in the facial nucleus, where it appeared as fluorescent granules 9 h after the injection. The fluorescence intensity increased with increasing exposure times and concentrations of the injected tracers. The motor endplates showed no ultrastructural changes after the tracer injections. The motor endplates showed no ultrastructural changes after the tracer injections. With this method a substantial increase in tracer accumulation in facial neurons could be revealed during nerve regeneration 11 days after crushing the facial nerve. Small alterations in neuronal tracer accumulation could be measured after intoxication of the mice with botulinum and tetanus toxins. Since these toxins should cause a decrease or increase in the degree of synaptic activity the amount of retrograde axonal transport may to a certain extent be dependent on the synaptic function. The findings with this new technique therefore indicate that quantitative changes occur in axonal transport in materials from the periphery during different pathological and physiological conditions, which may be important for an understanding of how a nerve cell body is dependent on its peripheral field of innervation.

Animals↗
PubMed1980

Further studies on subacute encephalitis and hydrocephalus in hamsters caused by measles virus from persistently infected cell cultures.

Newborn hamsters were inoculated intracerebrally (IC) with disrupted measles carrier Lu 106 cells. No acute neurological disease developed, but limited, persistent neural infection was identified by immune fluorescence and by virus isolation. By ten days after inoculation, virus could be recovered only by cocultivation of explant cultures of central nervous system (CNS) tissue and Vero cells. Virus was still demonstrable in CNS by both techniques 50 days after inoculation, the latest sample collected. Animals inoculated as newborns developed a poor hemagglutination-inhibiting (HI) antibody response. In three-week-old hamsters inoculated IC no detectable replication of carrier virus occurred. The serum HI antibody response was more than 20 times higher than that in animals inoculated as newborns. Hydrocephalus developed in a fraction of animals inoculated at birth or at the age of three weeks. Both infectious and heat-inactivated disrupted virus carrier material, but not control material of Lu 106 cells, gave hydrocephalus. The precise mechanism leading to hydrocephalus is unclear. Carrier virus material may produce a meningeal irritation causing disturbances of the extraventricular flow or resorption of cerebrospinal fluid, leading to communicating hydrocephalus. Infectious carrier virus may replicate in and destroy ependymal cells, further contributing to hydrocephalus.

Age Factors↗
PubMed1980

Cellular immune response in rabbits immunized with purified Visna virus.

Visna virus-sensitized lymphocytes were demonstrated in the peripheral blood of rabbits following immunization with purified, concentrated visna virus. Lymphocytes sensitization was maximal at about 2 weeks and fell to control levels in 5 weeks. A delayed-type cutaneous hypersensitivity to the virus was observed at 2 weeks and lasted for at last 9 weeks. Both reactions increased after a booster injection. Although sera from immunized rabbits had precipitating antibodies against visna virus protein P25, their lymphocytes were not stimulated by P25. However, there was a slight reaction to P25 in the skin test. Therefore, in contrast to the humoral immune response, P25 is apparently not the most active viral antigen in the CMI response in rabbits.

Animals↗
PubMed1979

Uptake of horseradish peroxidase in sensory nerve terminals of mouse trigeminal nerve.

Uptake of horseradish peroxidase (HRP) in sensory nerve terminals in sinus hair in the nose of the mice was studied after local (s.c.) or i.v. injections. HRP spread into the sinus hair follicles and surrounded the nerve terminals of the Merkel disc endings and lanceolate terminals. It was incorporated into vacuoles and vesicles of these terminals. Subsequently, HRP was demonstrated in nerve cell bodies in the ophthalmo-maxillary part of the trigeminal ganglion, indicating a somatopetal axonal transport of the tracer. In this way the sensory neurons may be subjected to various influences from the periphery.

Animals↗
PubMed1979

Myelin lesions in the rabbit eye model as a bystander effect of herpes simplex and visna virus sensitization.

Rabbits were immunized with herpes simplex and visna virus in complete Freund's adjuvant. Uv-inactivated herpes virus and the purified visna virus protein p25 injected intraocularly into these rabbits elicited a moderate inflammatory cell infiltration in the epiretinal myelinated nerve fiber bundles accompanied by signs of demyelination. It is therefore apparent that also viral antigen can induce myelin lesions as a so-called "bystander effect" of a cell-mediated immune response (bystander demyelination).

Animals↗
PubMed1979

Observations on the effect of injection of lymphocytes from multiple sclerosis and Guillain-Barré syndrome in the rabbit eye model.

The effect of 10 X 10(5) peripheral blood lymphocytes (PBL) obtained from patients with multiple sclerosis (MS), Guillain-Barré syndrome (GBS) and healthy controls was studied after injection into the rabbit eye. Infiltration of inflammatory cells, strikingly localized to myelinated strips, was obtained with PBL from some of the MS patients and controls, indicating the non-specificity of the phenomenon. PBL from 2 GBS patients gave the strongest infiltration. No effect was obtained with 10 X 10(4) PBL or CSF lymphocytes from MS patients, indicating that the number of lymphocytes is an essential factor in the induction of lesions.

Adult↗
PubMed1979

Latent herpes simplex virus trigeminal ganglionic infection in mice and demyelination in the central nervous system.

Mice were inoculated with herpes simplex virus (HSV) type 1 by gently scraping the skin of the nose with a fine needle. About 80% of the animals developed latent inapparent HSV infections in trigeminal ganglia. Virus was demonstrable for at least 6 months post inoculation (p.i.) by cocultivation of ganglionic tissue with GMK cells. Histologically, trigeminal ganglia revealed infiltrations of inflammatory cells even 6 months p.i. In addition, lesions occurred in the brainstem corresponding to the entry of trigeminal roots, trigeminal tracts and nuclei. Inflammatory cell infiltration, disruption of myelin sheaths and macrophages laden with myelin degradation products were observed 7 days p.i. Fourteen to 30 days p.i. electron microscopy demonstrated completely naked axons. In the transitional region of the trigeminal root denuded axons occurred in the central part of the region while the peripheral myelin, bordering the demyelinated central segments, was intact. Small areas of demyelination were still detectable 3 and 6 months p.i. but there were then also signs of remyelination. Possible mechanisms causing the demyelinations are discussed.

Animals↗
PubMed1979

Myelinotoxic activity on tadpole optic nerve of cerebrospinal fluid from patients with optic neuritis.

The myelinotoxic activity of unconcentrated cerebrospinal fluid (CSF) from eight optic neuritis (ON) and five multiple sclerosis (MS) patients with oligoclonal IgG, and from five ON patients without oligoclonal IgG, was tested in the tadpole optic nerve system. CSF from ON or MS patients with oligoclonal CSF IgG gave a significantly greater number of myelinotoxic lesions than did CSF from ON patients without oligoclonal CSF IgG, CSF from control patients, or physiologic saline. Induction of myelinotoxic lesions may be coupled with the presence of oligoclonal IgG. The findings support the hypothesis that there are two different forms of ON, of which one, characterized by oligoclonal IgG in the CSF, is more closely related to MS.

Adult↗
PubMed1978

Uptake and retrograde axonal transport of various exogenous macromolecules in normal and crushed hypoglossal nerves.

Macromolecular tracers were injected into the tongue or around a crush in mouse hypoglossal nerves. At various times thereafter, the tracers were histochemically localized on the basis of peroxidase activity. The distribution of reaction product was then examined using light microscopy in order to study the influence of molecular charge and size on uptake and retrograde axonal transport from the periphery or from the crushed axon. Of various proteins with peroxidase activity, horseradish peroxidase and cytochrome-c showed the greatest penetration into axons proximal to the crush. Following injection into the tongue, intra-axonal cytochrome-c was detectable in some of the peripheral branches but not any of the other proteins. Retrograde transport to the nerve cell bodies was demonstrated for horseradish peroxidase and cytochrome-c, both from the tongue and from the axonal crush but not for microperoxidase, myoglobin, hemoglobin, lactoperoxidase and catalase. The number of neuronal cell bodies having detectable reaction product was higher for peroxidase-injected than for cytochrome-c-injected animals. Ferritin and iron-dextran (Imferon) also accumulated in hypoglossal neurons, but this could be detected only after repeated injections into the tongue. Uptake and retrograde transport from the tongue or from the crush occurred both for anionic and for cationic horseradish peroxidase. This is interpreted as evidence against absolute specificity in the uptake and transport of macromolecules on the basis of electrical charge.

Animals↗
PubMed1978

Studies on hexachlorophene-induced myelin lesions in the trigeminal root transitional region in developing and adult mice.

Hexachlorophene (HCP)-induced intramyelinic vacuolation was studied in the transitional region of the trigeminal root of suckling and adult mice. HCP produced an extensive vacuolation in the central compartment of the region in both suckling and adult mice, while in the peripheral compartment myelin lesions were only seen in mice less than 16 days of age. Gas chromatographic measurements showed that in suckling mice the blood concentration of HCP decreased with age, apparently reflecting a faster elimination of HCP from the blood. By substantially increasing the HCP dose, higher blood concentrations were obtained in adult than less the 16-day-old mice; in spite of this, PNS myelin changes occurred only in the latter. Thus, by observing the HCP effect on the transitional region, where CNS and PNS directly meet, it is concluded that CNS of both suckling and adult mice is more severely effected by HCP than PNS, and that the reaction of the PNS myelin is age-dependent during the period of myelinogenesis; it is particularly vulnerable to a cytotoxic edema inducing substance.

Age Factors↗
PubMed1978

Subacute encephalitis and hydrocephalus in hamsters caused by measles virus from persistently infected cell cultures.

Newborn hamsters were inoculated intracerebrally with measles virus materials from Lu 106 and Vero carrier cell lines. Extracellular and cell-associated materials from cultures incubated at 37 degrees C and at 33 degrees C were used. The lower temperature allows accentuated virus replication. No animals contracted acute encephalitis, but 8 animals developed advanced neurological disease (unsteady gait, serial myoclonic jerks, hypoactivity) 79 to 212 days after injection. Seven out of these 8 animals belonged to a group of 50 animals, which had been inoculated with cell-associated material from cultures incubated at 33 degrees C. Viral antigen and nucleocapsids were found in neurons and glial cells from diseased animals, which showed degenerative changes and inflammation, particularly in the mesencephalon. Some of these animals also had hydrocephalus, which, however, also occurred in many apparently healthy animals. Also this pathological alteration occurred most frequently (5 out of 11 animals examined 9--10 months after inoculation) in hamsters receiving cell-associated material from carrier cutlures incubated at 33 degrees C. Possible mechanisms for the appearance of hydrocephalus are discussed.

Animals↗
PubMed1978

Uptake and retrograde axonal transport of horseradish peroxidase in regenerating facial motor neurons of the mouse.

Uptake and retrograde axonal transport of intravenously injected horseradish peroxidase (HRP) was studied during regeneration after a crush injury of the facial nerve of the mouse. The circulation time of HRP was 12 to 24 h. HRP injected immediately after the crush diffused into injured axons in the crushed region and accumulated subsequently in perikarya of facial neurons in the brain stem. After a time interval of 1 h or 5 days between the crush and the injection only a faint HRP accumulation occurred in a few facial neurons. After an interval of 7 days a moderate number of neurons had incorporated the tracer, while after more than 9 days the HRP activity in the regenerating neurons was more pronounced than in the contralateral neurons. Ultrastructurally, muscles of the vibrissae showed denervated subneural apparatuses 6 days after the crush. 8 days after the crush regenerating axon terminals containing small clusters of synaptic vesicles, dense cored vesicles and some HRP-labelled vesicles, were found over some gutters and after 10 to 13 days all examined gutters contained axon terminals with large numbers of synaptic vesicles and some HRP-containing vesicles. More than one axon terminal profile was seen in the same synaptic gutter. 32 and 64 days after the crush the neuromuscular junctions had regained a more mature appearance. The calibre spectra of the crushed facial nerves still showed a shift towards smaller diameters 134 days after the crush, at a time when a slight increase in HRP activity in the facial neurons persisted.

Animals↗
PubMed1978

Neural spread of herpes simplex virus types 1 and 2 in mice after corneal or subcutaneous (footpad) inoculation.

Twelve herpes simplex virus (HSV) strains, 6 of each type, were inoculated subcutaneously into the left hind foot and into the cornea of the right eye of 12-day-old Swiss albino mice. The neural spread of virus to trigeminal and spinal ganglia and to brain and spinal cord was studied by demonstration of infective virus, histology and electron microscopy. Type 1 and type 2 infections seemed to spread equally well by intra-axonal transport. Using a protein tracer (horseradish peroxidase) injected into the same site as the virus, transport of the tracer to neurons corresponding to those infected with virus was observed. The extensive destruction of CNS tissue in the transitional region of the trigeminal root where CNS and the peripheral nervous system meet is discussed with reference to the pathogenesis of HSV encephalitis.

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