Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “OLFACTORY NERVE”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 1,099 records · Page 61Linked to original sources
PubMed1984

Sendai virus infection in the mouse brain: virus spread and long-term effects.

Following intranasal instillation of Sendai virus in newborn mice an extensive virus infection of respiratory epithelium and olfactory mucosa was observed by immunoperoxidase technique. Viral antigen appeared in olfactory nerves and in neurons of the trigeminal ganglia. Selective labeling of neurons in trigeminal ganglia was also seen after virus injection into the snout. This shows that respiratory infections may not be restricted to the respiratory mucosa but may also spread to peripheral ganglia after uptake of virus at axonal terminals and somatopetal axonal transfer to the nerve cell bodies. Following intracerebral injection into newborn mice viral antigen persisted in scattered neurons in the thalamus and mesencephalon after 24 weeks. The majority of the mice developed hydrocephalus, for which obliteration of the aqueduct seems to have been a major cause.

Animals↗
PubMed1993

Detection of active and latent feline herpesvirus 1 infections using the polymerase chain reaction.

A polymerase chain reaction (PCR) assay was developed to detect the thymidine kinase gene of feline herpesvirus 1 (FHV-1) and to study the active and latent carrier state in a group of naturally FHV-1 infected specific pathogen free (SPF) cats. The detection limit of PCR products on ethidium bromide stained gels was 390 fg or about 3 x 10(3) copies of the FHV-1 genome. The PCR was 25% more sensitive than conventional cell culture based virus isolation techniques in detecting FHV-1 in oral/ocular swabs and 100 times more sensitive in detecting virus in cell culture supernatants. Sites of FHV-1 latency in FHV-1 carriers as determined by PCR were mainly tissues of the head, especially the trigeminal ganglia, optic nerves, olfactory bulbs and corneas. Oral fauces, salivary glands, lacrimal glands, cerebellum and conjunctiva were less consistently positive. The cerebral cortex, thymus, trachea, lung, liver, spleen, kidney, and peripheral blood mononuclear cells were consistently negative for FHV-1 genome. The distribution of FHV-1 DNA in the tissues of the head was similar whether or not corticosteroid-induced virus shedding was occurring at the time the tissues were collected. Infectious virus was never recovered from tissue homogenates regardless of the PCR status of the tissues.

Animals↗
PubMed1993

Modified bifrontal interhemispheric approach to aneurysms of the anterior communicating artery with the use of a trephine craniotomy. A review of personal experience with 25 cases.

A modified microsurgical bifrontal interhemispheric approach (small trephine craniotomy) for clipping of aneurysms of the anterior communicating artery (ACoA) is described. This approach has been used in a series of 23 patients with ACoA and 2 patients with distal anterior cerebral artery aneurysms. Feasibility, indications and problems related to this approach to ACoA aneurysms are assessed. Twenty-one patients (84%) made an excellent or good recovery. The result was poor in an 80-year-old patient who was in grade 3 pre-operatively. Three patients of this series died: one of them was pre-operatively in grade 4 and died from pneumonia; the other two died as consequence of unrelated ailments. Incidence and extent of vasospasm was within the normal range, corresponding to the amount and distribution of subarachnoid blood clots. From our experience it can be concluded that this approach is safe and feasible for patients with ACoA aneurysms graded 1-2 (Hunt-Kosnik's grading system) and evaluated as group 1-2 of Fisher's CT classification. But it is not recommended for patients with larger amounts of subarachnoid blood clots. Advantages of this microapproach to ACoA aneurysms are: a) minimal brain damage, b) adequate visualization and anatomical orientation, c) preservation of the olfactory nerves and the gyrus rectus, d) reduced operative time, e) easy clip application to aneurysms pointing in any direction.

Adult↗
PubMed1982

The microsurgical anterior interhemispheric approach suitably applied to ruptured aneurysms of the anterior communicating artery in the acute stage.

From 1973 to 1980, 177 cases with ruptured aneurysms of the anterior communicating artery (Aco) have been operated on using various microsurgical procedures. Since 1974, 136 cases were directly operated on using the microsurgical anterior interhemispheric (AIH) approach: a modification of Lougheed's approach. The overall mortality was 5%. The early operations, within 1 week of onset of subarachnoid haemorrhage had a 3% mortality in grade 1 and 2 patients; a 16% mortality in grade 3 and 4 and a 25% mortality in grade 5 patients. The rate of cases in which the patient was independent following surgery was 92% in grade 1 and 2 patients, 47% in grade 3 and 4, and 25% in grade 5 in the same group. The AIH approach for severe cases in the acute stage has the following benefits: 1. The retraction pressure on the brain in the AIH approach is half as much as that in Yaşargil's approach. The aneurysms can be operated on with less retraction of the brain and thus without damaging the brain, olfactory nerves, bridging veins, hypothalamic arteries and other perforating arteries. 2. Various types of aneurysms, whatever their position, especially those located high and in a posterior direction, can be easily clipped. 3. Adequate removal of clots can be achieved from the interhemispheric fissure, the chiasmatic and the prepontine cisterns and the frontal lobe. 4. Interarterial anastomosis between both anterior cerebral arteries can be applied if necessary to allow easy clipping on unusual aneurysms. 5. Temporary occlusion of A1's and A2's and external decompression can be easily done if necessary.

Acute Disease↗
PubMed1997

Control of complications in the midfrontobasal approach.

Many surgical techniques are employed for access to midline lesions of the anterior and middle fossa. A convenient one is the midfrontobasal approach. For various indications this surgical procedure was performed in 105 patients. Its benefits are outlined and a method for dealing with the two main drawbacks, postoperative loss of the sense of smell and the presumed risk of infection related to the inevitable opening of the frontal sinus, are described. In 83% of the cases the authors were able to anatomically retain the olfactory nerves, with preservation of the sense of smell in at least 65% of them. The frontal sinus was opened in 76% of the cases. The incidence of infection in the simple and quick integral reconstruction appeared 1%, equal to the rate of infection in the classical reduction of the frontal sinus by a periosteal flap.

Adolescent↗
PubMed2001

Targeting of olfactory neurons.

Olfactory sensory neurons detect an enormous variety of small volatile molecules with extremely high sensitivity and specificity. The actual recognition and discrimination of odorous compounds is accomplished by specific receptor proteins located in the ciliary membrane of the sensory neurons. Axonal connections into the olfactory bulb, the first relay station for odor processing in the brain, are organized such that all neurons expressing the same odorant receptor converge their axons onto common glomeruli which are located at similar positions in all individuals from one species. For the establishment of this precise targeting of olfactory axons to their appropriate glomeruli, combinatorial functions of axon-associated cell adhesion molecules and odorant receptor proteins appear to be required. Odorants that stimulate distinct receptor cell populations will thereby activate a specific combination of glomeruli in the bulb; this characteristic activity pattern may be used by the system to encode the quality of a particular odorant.

Animals↗
PubMed2003

Reassessment of the pathways responsible for cerebrospinal fluid absorption in the neonate.

OBJECTIVE: In neonatal lambs, the quantitative evidence suggests that a significant volume of cranial CSF drainage is associated with transport along olfactory nerves with absorption primarily into extracranial lymphatics in the paranasal region. Arachnoid granulations appear to be poorly developed at this level of development and their function is unknown. In this report, we tested whether a CSF protein tracer ((131)I-human serum albumin) could transport directly into the superior sagittal sinus of newborn lambs. METHODS AND RESULTS: The concentration of the tracer administered into the CSF compartment was measured in the confluence of the intracranial venous sinuses (torcula) and in the peripheral blood (inferior vena cava). Enrichment of the CSF tracer in the cranial venous system was most evident when the CSF-venous sinus pressure gradients approached 20-30 cm H(2)O. CONCLUSION: The data suggests that neonatal CSF can be absorbed directly into the cranial venous system. However, contrary to the classical view, this route may represent an auxiliary system that is recruited to compliment lymphatic transport when intracranial pressures are very high.

Absorption↗
PubMed2006

Oral infection of immunocompetent and immunodeficient mice with Balamuthia mandrillaris amebae.

Balamuthia mandrillaris is an opportunistic agent of lethal granulomatous amebic encephalitis (GAE). In mice, we have shown that intranasally instilled B. mandrillaris amebae infect the brain via the olfactory nerve pathway. In this study, we raised the question whether this ameba might also reach the brain after an oral/gastrointestinal infection. Immunocompetent (WT) and immunodeficient (RAG) mice received B. mandrillaris amebae by gavage into the esophagus. Mice of both groups became ill and some died (WT 20%, RAG 40%) within 42 days. All orally infected mice revealed B. mandrillaris amebae in the central nervous system. Outwardly intact amebae and/or specific antigen were found widely distributed in various organs and the stool. The data indicate that oral infection with B. mandrillaris leading to GAE is possible. Exit from the gastrointestinal tract and dissemination remains unresolved. Though stool cultures were negative, transmission of this highly pathogenic ameba via stool cannot be ruled out.

Amebiasis↗
PubMed1997

Basic principles and molecular mechanisms of olfactory axon pathfinding.

The present review describes several lines of recent evidence providing new insights into the basic principles and mechanisms of axon projection from the olfactory epithelium to the olfactory bulb. Olfactory sensory neurons are classified into approximately 1000 subtypes according to the expression of specific odorant receptors. Olfactory sensory neurons expressing a given odorant receptor are distributed within one zone out of the four circumscribed zones of the olfactory epithelium and send their axons to the corresponding zone of the olfactory bulb: the principle of zone-to-zone projection. We discuss possible functions of a novel cell adhesion molecule, viz., OCAM, in the formation and maintenance of zone-to-zone projection of both olfactory and vomeronasal axons. Furthermore, olfactory sensory neurons expressing a given odorant receptor converge their axons onto only two topographically fixed glomeruli among the 1500-3000 glomeruli in the olfactory bulb: the principle of glomerular convergence. These axonal connection patterns give rise to the response specificity of the second-order neurons, viz., the mitral/tufted cells, to a particular range of odor molecules. In the process of glomerular convergence, combinatorial functions of axon-associated cell adhesion molecules and odorant receptor proteins may be required for the establishment of the precise targeting of olfactory axons to the appropriate glomeruli.

Animals↗
PubMed1998

Localization of calcitonin gene-related peptide mRNA in developing olfactory axons.

During development of the olfactory pathway, calcitonin gene-related peptide (CGRP) expression is regulated both temporally and spatially. We had previous evidence that between E13 and E19 CGRP mRNA was present at the level of olfactory axons but the resolution of light-microscope in situ hybridization did not permit the axons to be distinguished from the closely apposed ensheathing cells. In this study, the localization of CGRP mRNA was studied at early developmental stages (E13-15) through in situ hybridization at the transmission electron-microscope (TEM) level. CGRP transcripts were observed exclusively in axons and not in ensheathing cells. The distribution of transcripts in the axons suggests that they are associated with intermediate filaments rather than microtubules. In addition, a careful ultrastructural analysis provided evidence that polysomes and membrane-bound ribosomes are present in such axons, suggesting that the peptide could be synthesized locally.

Animals↗
PubMedDate not supplied

Case of complex craniofacial anomalies, bilateral nasal proboscides, palatal pituitary, upper limbs reduction, and amnion rupture sequence: disorganization phenotype?

We report a case of a dizygotic twin with complex abnormalities of head, body, and limbs. The anomalies include the following: lateral and midline cleft upper lip, ectopic palatal pituitary, natal teeth, bilateral nasal proboscides with an absent nose, left microphthalmia with conjunctival-lined cyst, right ocular dysgenesis, bilateral retinal dysplasia, platybasia with skull asymmetry, hydrocephalus secondary to aqueductal atresia, brain hemispheric asymmetry with a parietal-occipital cortical flap, agenesis of posterior corpus callosum, absence of the olfactory nerves and left anterior cerebral artery, leptomeningeal and intraventricular heterotopias, right radial longitudinal terminal meromelia with constriction rings of fingers, partial syndactyly of the third and fourth left fingers, dorsiflexed great toes and pes equinovarus bilaterally, and multiple skin tags with a sacral appendage. Additionally, this twin's placental disc and extraplacental membranes were devoid of amnion. We regard these anomalies as a possible expression of the human homologue of the disorganization phenotype or another gene mutation. Nevertheless, an abnormality of blastogenesis with early damage to organizing tissues of the frontonasal region and limbs, or a vascular disruption, cannot be excluded. Early amnion rupture sequence (possible extraamniotic pregnancy with amniotic bands, limb reduction defects with Streeter bands, and multiple skin tags tapering into amniotic bands) was also present in this case, and may have acted as a contributing factor.

Abnormalities, Multiple↗
PubMed1978

Qualitative and quantitative odour discrimation by mitral cells as compared to anterior olfactory nucleus cells.

The responses to odour stimulation of 61 single mitral cells and of 64 single anterior olfactory nucleus (AON) units were simultaneously recorded from rabbits. The test battery consisted of 6 chemical stimuli delivered at two intensity levels corresponding to a hundred-fold difference in concentration. The odour discrimination reaches its best for the mitral cells stimulated weakly; it decreased somewhere when the same cells are stimulated strongly. At AON level the odour discrimination already limited in the case of weak stimuli, almost disappears for strong stimuli. Multidimensional analysis of the odour similarities, respectively in the olfactory bulb and the AON, reveals an unexpectedly high loading of the first axis with an intensity factor. Our results indicate that the discriminatory ability in the mitral cells and in the AON cells are respectively better and poorer than in the chemoreceptors.

Animals↗