ABSTRACT
Background: The olfactory system has several interesting anatomical and physiological features althougholfaction has remained a ‘neglected sense’. Olfactory functioning is a valid indicator of the ageing brain sopresent study was designed to investigate the age of appearance of corpora amylaecia in the olfactory bulb andtract and compare with well known cases of Alzheimer’s disease.Aims of the study: To detect deposition of corpora amylaecia in the human olfactory bulb and tract in differentage groups and Alzheimer’s disease.Materials and Methods: 22 brain specimens were collected from cadavers from Anatomy department of MGMMedical College, Navi Mumbai and from National Institute of Mental Health and Sciences (NIMHANS), Bangalore.The study was carried out in 20 undemented specimen, divided into four groups (5 samples in each) according toage: group I (20-39yrs), group II(40-59yrs),group III (60-79yrs),group IV(80 yrs and above) and 2 specimen ofAlzheimer’s disease as a control group. Histological evaluation was done with Haematoxylin and Eosin stain,Luxol fast blue stain and Immunohistological stain, Glial fibrillary acidic protein (GFAP) antibody to studycorpora amylaecia. Statistical analysis was carried out using Chi Square test.Results: In group II, 20%, in Group III and Group IV 80% samples have showed presence of corpora amylaecia. Incontrols 100% samples had corpora amylaecia. This difference between five groups was statistically significant.In group II, corpora amylaecia was small in size, circular, deeply basophilic and scattered. In group III, IV and V,corpora amylaecia was large in size, more in number and condensed.Conclusion: The present study concluded that corpora amylaecia appear as early as fifth decade of life. Corporaamylaecia are age and neurodegeneration related phenomena and their number and size increase with age.Deposition of the corpora amylaecia in the olfactory bulb and tract may be responsible for olfactory dysfunctionin advanced age and neurodegenerative disorders
ABSTRACT
The olfactory bulb and tract (OB/OT) are among the earliest structures in the brain to undergo pathological changes in many neurodegenerative conditions. The availability of OB/OT samples from brain specimens in brain banks therefore assumes importance. We collected data from 5 years (2006-2010) regarding the presence or absence of OB/OT material in cases received by the Queen Square Brain Bank (QSBB) for Neurological Disorders, UCL Institute of Neurology, UK, to estimate availability of OB/OT material at the brain bank and also to look for possible associations. Of the 438 cases received, 320 had complete data regarding OB/OT and 29.4% of these had OB/OT in at least one half of the specimen. Unavailability of OB/OT was associated with larger post-mortem delays (p<0.001), suggesting that the delay might render the tissue more friable and hence lead to its loss. Brains from female donors also tended to have a higher availability in our samples.
O bulbo e o trato olfatórios (OB/OT) são algumas das estruturas cerebrais mais sensíveis a neurodegeneração. A disponibilidade deste material para estudos neuropatológicos em bancos de cérebro tem, portanto, grande relevância. Coletamos dados referentes a 5 anos (2006-2010) a respeito da presença ou ausência de OB/OT no Queen Square Brain Bank (QSBB) for Neurological Disorders, parte do UCL Institute of Neurology, Reino Unido, para estimar a disponibildade deste material em um banco de cérebro, e também para estudar fatores que influenciam essa disponibilidade. Dos 438 casos recebidos, encontramos dados referentes a presença ou ausência de OB/OT em 320, dos quais 29,4% possuiam OB/OT em pelo menos um lado. A indisponibilidade de OB/OT foi associada a maior intervalo entre a morte e a autópsia(p<0.001), sugerindo que o atraso pode deixar o material mais friável, levando aperda durante a coleta. Cérebros de doadoras femininas apresentaram maior disponibilidade de OB/OT em nossa amostra.
Subject(s)
Female , Humans , Male , Olfactory Bulb , Tissue Banks/statistics & numerical data , Autopsy , Sex Factors , Time Factors , United KingdomABSTRACT
Nervous system lesions are characterized by the loss of neuronal numbers and types. The neurotrophic factor levels in an injured tissue reflect their potential for regeneration. This hypothesis was investigated in olfactory bulb (OB), where olfactory tract was surgically transected disrupting neuronal migration and turnover. The effects were followed with quantification of mitral cells and three neurotrophic factors mRNA levels for 6 weeks. The neuronal numbers decreased by 3rd- and 4th-week in transected OBs followed by their restoration, comparable with that of controls at 5th- and 6th-week. The endogenous levels of three neurotrophic factors – (brain derived neurotrophic factor, insulin growth factor-1 and fibroblast growth factor-2) using qPCR showed increase at 2nd-week by 136-, 8- and 2-fold respectively. Also, there was a significant increase in specific neurotrophic factors at 5th-week and 6th-weeks. The results propose a temporal link between deployment of neurotrophic factors and the plausible restorative events for mitral cell numbers in OB.
ABSTRACT
Central Nervous System (CNS) regeneration and repair mechanism are two important aspects of functional recovery in the adult central nervous system following brain and spinal cord injury. Following olfactory tract transection in neonatal rats, functional connectivity between the olfactory bulb and the piriform cortex gets re-established by 120 days. The recovery of the dendritic morphology was associated with the synchronized oscillatory activity between olfactory bulb and piriform cortex. Mitral cells which were regenerated after the transection showed profuse branching, indicative of their undifferentiated state. However, normal dendritic morphology could be seen by 120 days after olfactory tract transection. These results thus provide a supportive evidence for the restoration of the functional connections between the olfactory bulb and the piriform cortex at 120 days.
ABSTRACT
We present a case of olfactory schwannoma in a 16-year-old boy with headache and diplopia. Brain computed tomography (CT) scan and magnetic resonance(MR) imaging showed a huge mass in the subfrontal area resembling an olfactory groove meningioma. We performed a bifrontal craniotomy and found out the mass was attached to cribriform plate but was not related to the olfactory tract or bulb. The histopathological diagnosis of schwannoma was confirmed by immunohistochemical staining for S-100, vimentin and others. We describe the clinical manifestations, radiological characteristics, histological aspects, and differential diagnosis of this tumor with literature review.