Olfaction in Juvenile Nasopharyngeal Angiofibroma: The first study.

BACKGROUND: To study the pattern of olfactory dysfunction/recovery in juvenile nasopharyngeal angiofibroma (JNA). METHODS: Olfactory assessment was undertaken in 30 patients (category1) both pre- & post-operatively and in another 18 (category 2) only postoperative. All patients underwent transpalatal excision and variables of interest included age, radiological stage/parameters & tumor size. RESULTS: Objective olfactory dysfunction was seen in 60% while involvement of olfactory strip was suggested in 50%. Despite some marginal trends only noted between size/age with change of olfaction, Pearson's correlation test did not reveal any significance amongst multiple variables. However a better recovery of olfaction following surgery was evident in Category-2 where Chi-Square test (p < 0.05) significantly revealed this to be a function of postoperative duration. This regenerative course in JNA suggests an optimum period of 4 years for full recovery after surgery. CONCLUSION: In this first study of olfaction in JNA many new trends have been appreciated. In general, deteriorations of olfaction were seen due to 'vascular-concussion' effect in early postoperative phase where post-surgical clearance of airway showed minimal effect in terms of improvement. The hypervascularity of olfactory epithelium with possible hormonal effects may be responsible for the unique pattern of olfactory function and recovery in JNA.

Olfactory evaluation in Mild Cognitive Impairment: correlation with neurocognitive performance and endothelial function.

Mild Cognitive Impairment (MCI) is an intermediate condition between normal aging and dementia, associated with an increased risk of progression into the latter within months or years. Olfactory impairment, a well-known biomarker for neurodegeneration, might be present in the condition early, possibly representing a signal for future pathological onset. Our study aimed at evaluating olfactory function in MCI and healthy controls in relation to neurocognitive performance and endothelial function. A total of 85 individuals with MCI and 41 healthy controls, matched for age and gender, were recruited. Olfactory function was assessed by Sniffin' Sticks Extended Test (Burghart, Medizintechnik, GmbH, Wedel, Germany). A comprehensive neurocognitive assessment was performed. Endothelial function was assessed by flow-mediated dilation (FMD) of the brachial artery by ultrasound. MCI individuals showed an impaired olfactory function compared to controls. The overall olfactory score is able to predict MCI with a good sensitivity and specificity (70.3 and 77.4% respectively). In MCI, olfactory identification score is correlated with a number of neurocognitive abilities, including overall cognitive status, dementia rating, immediate and delayed memory, visuospatial ability and verbal fluency. FMD was reduced in MCI (2.90 ± 2.15 vs. 3.66 ± 1.96%, P = 0.016) and was positively associated with olfactory identification score (ρs =0.219, P = 0.025). The association remained significant after controlling for age, gender, and smoking. In conclusion, olfactory evaluation is able to discriminate between MCI and healthy individuals. Systemic vascular dysfunction might be involved, at least indirectly, in olfactory dysfunction in MCI.

Anticancer drug vinblastine sulphate induces transient morphological changes on the olfactory mucosa of the rabbit.

Vinblastine sulphate (VBS) is an anticancer drug that acts by disrupting microtubule dynamics of highly mitotic tissue cells. The consequences of VBS on the olfactory mucosa (OM), a tissue with high mitotic numbers, are not clearly understood. We used qualitative and quantitative methods to determine the structural changes that may be produced on the rabbit OM by VBS. Following a single dose (0.31 mg/kg) of this drug, the structure of the mucosa was greatly altered on the first 3-5 days. The alteration was characterized by disarrangement of the normal layering of nuclei of the epithelia, degeneration of axonal bundles, occurrence of blood vessels within the bundles, localized death of cells of Bowman's glands and glandular degeneration. Surprisingly on or after day 7 and progressively to day 15 post-exposure, the OM was observed to regenerate and acquire normal morphology, and the vessels disappeared from the bundles. Relative to control values, bundle diameters, olfactory cell densities and cilia numbers decreased to as low as 53.1, 75.2 and 71.4%, respectively, on day 5. Volume density for the bundles, which was 28.6% in controls, decreased to a lowest value of 16.8% on day 5. In contrast, the volume density for the blood vessels was significantly lower in controls (19.9%) than in treated animals at day 2 (25.8%), day 3 (34.3%) and day 5 (31.5%). These findings suggest that the changes induced on the rabbit OM by VBS are transient and that regenerative recovery leads to the restoration of the normal structure of the mucosa.

Immunohistochemical, volumetric, and functional neuroimaging studies in patients with idiopathic Parkinson's disease.

Idiopathic Parkinson's disease (PD) is closely associated with olfactory loss. Deficits in the sense of smell may precede clinical motor symptoms by years. Although there is more and more evidence from recent studies to support this view, it remains unclear which substrates would cause the olfactory deficit. Studies based on biopsies from the olfactory epithelium did not reveal specific changes in the nasal mucosa of PD patients compared to patients who were hyposmic for other reasons. Thus, PD-related olfactory impairment seems not to be directly associated with specific changes in the olfactory epithelium. With regard to volumetrics of the olfactory bulb (OB) results indicated that there is little or no difference between PD patients and healthy controls in terms of OB volume. Again, these data support the idea that olfactory loss in PD is not a consequence of damage to the olfactory epithelium but rather results from central-nervous changes. Finally, studies based on functional MRI suggested that neuronal activity in the amygdala and hippocampus is reduced in PD patients compared to controls which may specifically impact on olfactory function. In addition, neuronal activity in components of cortico-striatal loops appears to be up-regulated indicating compensatory processes involving the dopaminergic system. Thus, it seems that cerebral changes, and not changes at the level of the olfactory epithelium, are the basis of the olfactory loss observed in PD patients.

The glucose transporter GLUT1 and the tight junction protein occludin in nasal olfactory mucosa.

The nervous cells in the brain and the peripheral nerves are isolated from the external environment by the blood-brain, blood-cerebrospinal fluid and blood-nerve barriers. The glucose transporter GLUT1 mediates the specific transfer of glucose across these barriers. The olfactory system is unique in that its sensory cells, olfactory receptor neurons, are embedded in the nasal olfactory epithelium and send their axons directly to the olfactory bulb of the brain. Only the apical parts of the olfactory receptor neurons are exposed to the lumen, and these serve as sensors for smell. Immunohistochemical examination showed that the tight junction protein occludin was present in the junctions of the olfactory epithelium. Endothelial cells in the blood vessels in the lamina propria of the olfactory mucosa were also positive for occludin. These observations suggest that the olfactory system is guarded from both the external environment and the blood. GLUT1 was abundant in these occludin-positive endothelial cells, suggesting that GLUT1 may serve in nourishing the cells of the olfactory system. Taken together, GLUT1 and occludin may serve as part of the machinery for the specific transfer of glucose in the olfactory system while preventing the non-specific entry of substances.

Vascularization of developing human olfactory neuroepithelium - a morphometric study.

The present study reveals intraepithelial capillaries in the olfactory neuroepithelium of human fetuses aged between 12 and 24 weeks of gestation, which disappear at birth. The area occupied by the intraepithelial capillaries increases significantly with fetal age (0.047 +/- 0.014 microm(2)/microm(2) at 12 weeks and 0.101 +/- 0. 025 microm(2)/microm(2) at 24 weeks) and with the thickness of the epithelium (45.00 +/- 6.74 microm at 8 weeks and 64.10 +/- 8.51 microm at 24 weeks). The vascularization of the developing neuroepithelium may suggest increased metabolic demand during development and maturation of the olfactory neuroepithelium, and postnatal retreat of capillaries to the underlying lamina propria may suggest diffusion of nutrients and gases from blood vessels into the lamina propria and direct gaseous exchange from the atmosphere.

Tachykinins and calcitonin gene-related peptide: co-existence in sensory nerves of the nasal mucosa and effects on blood flow.

The presence and co-existence of calcitonin gene-related peptide (CGRP)- and substance P (SP)-like immunoreactivity (-LI) in sensory neurons of the nasal mucosa and trigeminal ganglion in several vertebrate species, including man, were established using immunohistochemistry. In the nasal mucosa the CGRP- and SP-immunoreactive (IR) nerve fibers were localized within the epithelium, around arteries, arterioles, venules, venous sinusoids and close to exocrine elements, mainly ducts. Double-staining experiments revealed that the CGRP-LI-containing nerve profiles and cell bodies also contained SP-LI. In the pig, CGRP- and SP-IR fibers were also detected in the maxillary portion of the trigeminal nerve and around the sphenopalatine artery and vein, as well as around the nasal dorsal vein. The nasal mucosal content of CGRP-LI, as determined by radioimmunoassay, was almost 5-fold higher in the pig and guinea pig compared to man. The nasal CGRP-IR nerves disappeared after capsaicin pretreatment in the guinea pig. In the cat, local intra-arterial infusions of capsaicin, SP, neurokinin A (NKA), neuropeptide K (NPK) and CGRP caused a concentration-dependent increase in nasal blood flow. CGRP caused a longer-lasting vasodilatation than the tachykinins. In conclusion, the morphological findings of co-localization of CGRP-LI and SP-LI in capsaicin-sensitive nerve fibers of the nasal mucosa and trigeminal ganglia of different species including man, coupled with the in vivo description of the high vasodilator potency of CGRP and tachykinins, imply co-release of several vasoactive agents upon activation of the nasal sensory nerves. Furthermore, the similarity of the morphological findings among the different species indicates that experimental data from animals may reflect the existence of similar mechanisms in humans.

Fenestrated endothelia in vessels of the nasal mucosa. An electron-microscopic study in the rabbit.

The ultrastructure of the vessels in the normal respiratory and olfactory mucosa of the nasal septum was studied in 15 adult rabbits. Capillaries with continuous and fenestrated endothelia could be observed in both tissues. In the respiratory part, many of the fenestrated capillaries were located subepithelially with their fenestrations facing the adjacent epithelium. Fenestrated capillaries of the olfactory mucosa were found mainly in the deeper parts of the tunica propria and usually revealed only a small number of fenestrations in their endothelial lining. It was also demonstrated that muscularized veins sometimes displayed fenestrated areas in their attenuated endothelia. These results are discussed and compared with the appropriate literature. Our results confirm that there is a link between the morphological peculiarities of the vascular wall and the functional behaviour of the nasal mucosa. These findings also emphasize that endothelial fenestrations seem to be characteristic for a certain segment of the microcirculatory system rather than for a distinct type of capillary vessel.

[Blood vessels of the respiratory and olfactory mucosa of the rabbit. A light and transmission electron microscopy study]. / Die Gefässe der respiratorischen und olfaktorischen Schleimhaut des Kaninchens. Eine licht- und transmissionselektronenmikroskopische Untersuchung.

In our study, light and electron microscopic findings in vessels of the rabbit nasal respiratory and olfactory mucosa are reported. In the respiratory mucosa, most of the subepithelial tissue is occupied by large, sinusoidal veins which usually display oblong profiles in cross sections, while in the olfactory region the venous vessels occur less often and show round profiles. The arterioles are located close to the perichondrium, while the capillaries appear all over the lamina propria in both tissues. Fenestrated and continuous endothelia can be observed in capillaries of both the respiratory and olfactory regions.

Intraepithelial blood vessels in the vomeronasal neuroepithelium of the rat. A light and electron microscopic study.

Epithelial-vascular relationships are established during the development of the vomeronasal neuroepithelium of the rat. Special attention is given to the fine structure of the endothelial wall of intra-epithelial vessels, to ultrastructural aspects of the neuronal-vascular relationships, and to the appearance of inclusion bodies in the neuronal cells adjacent to these vessels. The neuronal perikarya surrounding the blood vessels are filled with highly developed smooth endoplasmic reticulum. Possible functional implications of the vascularization of the neuroepithelium of the vomeronasal organ in mediating olfacto-endocrine relationship are discussed. It is suggested that the intra-epithelial blood vessels are at least supportive and nutritive in nature, while their implication in an olfacto-endocrine connection remains obscure.

[Ethmoidal arteries: origin, course, regions supplied and anastomoses]. / Arteriae ethmoidales: Ursprung, Verlauf, Versorgungsgebiete und Anastomosen.

The origin, course and regions supplied by the ethmoidal arteries were studied on 30 injected adult heads. After branching off, the anterior ethmoidal artery normally makes a single smooth loop by first coursing forwards and then, reversing itself towards the anterior ethmoidal foramen, it goes into the canal portion, likewise without bend or angularity. Occasionally, a common ethmoidal artery or a common source for the ethmoidal arteries is present. Very rarely does the artery fail entirely. As a rule, the posterior ethmoidal artery arises from the ophthalmic artery. Occasionally, however, it is missing or can even very rarely arise from the A. meningea media. The artery usually crosses over the superior oblique muscle while the anterior ethmoidal artery usually goes under the same muscle. In the fossa olfactoria, the ethmoidal arteries give off their most important dura and bone branches in the anterior cranial fossa and then continue into the walls of the cavum nasi. The courses and variations along with ipsi- and contralateral anastomoses are likewise demonstrated.

Some anatomical and histological studies on the arterial supply of the nasal cavity of the buffalo in Egypt (Bos bubalis L.).

The nasal cavity of the buffalo received its blood supply from the sphenopalatine and the external ethmoidal arteries; the former vessel chiefly supplied the respiratory portion of the nasal mucosa, while the latter was distributed to the olfactory region. The greater palatine artery supplied a palatonasal branch in the most extreme oral part of the nasal floor. The nasal vestibule received bronches from both the maxillary labial and infraorbital arteries. The arteries are of the muscular type and presented in addition ot the usual structure of their walls, thin-walled and thick-walled types. Stalked polsters are encountered in the branches of the arterial vessels having walls of the normal thickness. The appearance of the longitudinally arranged smooth muscle fibers found in the intime of some of the subepithelial small arteries and arterioles is suggestive of their epitheloid structure.