Biomedical subjects

T V Getchell

Publications and source records attributed to T V Getchell.

At least 37 records · Page 2Linked to original sources

PubMed1995

Human olfactory receptor neurons express heat shock protein 70: age-related trends.

Immunocytochemical methods were used to investigate the cellular distribution and age-related trends in the expression of constitutive and/or inducible forms of heat shock protein (hsp) 70 in the human nasal mucosa of 22 subjects who ranged in age from 16 weeks prenatal to 90 years, including 3 subjects with Alzheimer's disease. The olfactory mucosa was characterized by the presence of olfactory marker protein-immunoreactive olfactory receptor neurons. The hsp 70 immunoreactivity was localized in olfactory receptor neurons and the supranuclear region of sustentacular cells in the olfactory epithelium, and in the acinar cells of the Bowman's glands in the lamina propria. A systematic age-related decrement in the expression of hsp 70 immunoreactivity was observed in the olfactory receptor neurons. This trend was not apparent in sustentacular cells and Bowman's glands. A marked decrement in hsp 70 immunoreactivity was also noted in the olfactory receptor neurons of subjects with Alzheimer's disease when compared to age-matched controls. These results suggest that the age-dependent decrease in hsp 70 in olfactory receptor neurons of older subjects and those with Alzheimer's disease may be attributable to their greater susceptibility to stress.

Adult↗

PubMed1995

Age- and gender-related trends in the expression of glutathione S-transferases in human nasal mucosa.

The cellular expression of alpha, mu, and pi classes of glutathione S-transferases (GSTs) was investigated in human nasal mucosa by means of immunocytochemical techniques. In the olfactory mucosa, immunoreactivity for GST-alpha was most intense in the acinar cells of the Bowman's glands, with weak immunoreactivity in the supranuclear region of sustentacular cells. Whereas GST-pi was localized only in the sustentacular cells, no GST-mu was detected. In the respiratory mucosa, GST-alpha and GST-pi were detected at the brush borders of ciliated columnar epithelial cells. There were age- and gender-related trends in the expression of GST-alpha, but not GST-pi, in the olfactory mucosa. The intensity of immunoreactivity in the olfactory mucosa was decreased in older subjects. The expression of GST-alpha in the olfactory mucosa of females consistently exhibited greater intensity than that of males at all the ages studied. These differences were not observed in the respiratory mucosa. These results indicate that acinar cells of the Bowman's glands and sustentacular cells are the major sites of phase II biotransformation in the human nasal mucosa.

Adult↗

PubMed1995

Innervation in human taste buds and its decrease in Alzheimer's disease patients.

The innervation in human taste buds of the foliate and circumvallate papillae was studied immunohistochemically using several neuronal markers in patients with Alzheimer's disease (AD) and their control (ADC) patients. Antisera to protein gene product 9.5 (PGP 9.5), neuron-specific enolase (NSE), tyrosine hydroxylase (TH), dopamine-beta hydroxylase (DbetaH) and calcitonin gene-related peptide (CGRP) were used in immunofluorescence and streptavidin-biotin-peroxidase complex studies. The antiserum to PGP 9.5 stained a greater number of intragemmal nerve fibers in taste buds than that of other antisera. PGP 9.5 immunoreactivity was strictly localized in the nerve fibers, whereas NSE immunoreactivity was observed not only in the nerve fibers, but also in taste bud cells. Intragemmal TH- and DbetaH-immunoreactive nerve fibers were not identified in taste buds. Only a few intragemmal nerve fibers immunoreactive for anti-CGRP antiserum were observe in a small number of taste buds. Furthermore, quantitive analysis in AD and ADC patients demonstrated that the mean number of PGP 9.5-immunoreactive intragemmal nerve fibers in taste buds of the foliate and circumvallate papillae decreased significantly in AD patients. These results indicated that PGP 9.5 is a most suitable molecular marker for the demonstration of the extrinsic innervation in human taste buds, and that the decreased innervation may account partially for the decrement in chemosensory capacity in AD patients.

Aged↗

PubMed1994

Expression of the putative pheromone and odorant transporter vomeromodulin mRNA and protein in nasal chemosensory mucosae.

In nasal chemosensory systems, glandular proteins associated with the vomeronasal and olfactory epithelia perform specific perireceptor functions associated with sensory transduction. Vomeromodulin, a recently identified glycoprotein synthesized by the lateral nasal glands, is proposed to be a pheromone transporter (Khew-Goodall et al., FASEB J 5:2976-2982, 1991). In our study, we have investigated its expression in vomeronasal, olfactory, and respiratory nasal mucosae of rats and humans using in situ hybridization and immunocytochemical techniques. In the rat, vomeromodulin mRNA and protein were localized abundantly in the glandular acini of the maxillary sinus component of the lateral nasal glands. In addition, the vomeronasal and posterior glands of the nasal septum also expressed vomeromodulin mRNA and protein. Vomeromodulin immunoreactivity was localized extracellularly in the mucus of the sensory and non-sensory epithelia of the vomeronasal organ, and in the mucociliary complex of the olfactory, respiratory, and associated nasal epithelia. In human nasal mucosae, vomeromodulin immunoreactivity was localized in the mucociliary complex of the vomeronasal and respiratory epithelia. Comparison of the localization of vomeromodulin with that of odorant-binding protein, which is also synthesized in the lateral nasal glands of rats, revealed that odorant-binding protein was expressed in a completely separate glandular region, namely the ventral component. In the septal glands, vomeromodulin was expressed in the posterior glands whereas odorant-binding protein was localized in the anterior glands. Odorant-binding protein immunoreactivity was not observed in the vomeronasal glands. In contrast, both proteins were localized in the mucus of vomeronasal, olfactory, and respiratory epithelia. Our results suggest that vomeromodulin, like odorant-binding protein, functions as a chemosensory stimulus transporter associated with perireceptor processes in vomeronasal and olfactory transduction.

Animals↗

PubMed1994

Neuronal nitric oxide synthase is localized in extrinsic nerves regulating perireceptor processes in the chemosensory nasal mucosae of rats and humans.

Nitric oxide synthase is the enzyme responsible for the production of the free radical gas nitric oxide, which has been implicated as an intercellular messenger in both the central and peripheral nervous systems. Immunoreactivity for nitric oxide synthase is often coincident with the histochemical demonstration of NADPH-diaphorase activity. Using an antibody to the neuronal form of nitric oxide synthase and a histochemical technique for NADPH-diaphorase, we have compared the localization of immunoreactivity and histochemical reaction product in the nasal mucosae of rats and humans. Immunoreactivity for neuronal nitric oxide synthase was localized in the extrinsic perivascular innervation of the olfactory and vomeronasal mucosae of rats and in the olfactory mucosa of humans. In the rat nasal mucosa, specific groups of glands were also innervated; the density of nitrinergic innervation varied among them, with vomeronasal glands and posterior glands of the nasal septum being the most densely innervated. In contrast, NADPH-diaphorase activity was present in olfactory, vomeronasal, and septal organ receptor neurons in rats and in olfactory receptor neurons in humans as well as in numerous nerve fibers, glands, and surface epithelial cells. The localization of neuronal nitric oxide synthase in extrinsic perivascular and periglandular nerve fibers suggests that nitric oxide may modulate the perireceptor processes of local blood flow and mucus secretion that influence the access to and clearance of chemical stimuli from rat and human chemosensory mucosae.

Adult↗

PubMed1994

Human and rodent OMP genes: conservation of structural and regulatory motifs and cellular localization.

Immunocytochemical analysis has demonstrated that expression of the olfactory marker protein (OMP) is highly restricted to mature olfactory receptor neurons in virtually all vertebrate species from fish to man. We have now cloned the OMP gene from human and mouse and demonstrated conservation of gene structure, protein sequence, and Olf-1 and upstream binding region (UBE) regulatory domains. The OMP gene in all species studied lacks canonical TATA and CAAT motifs and introns. The deduced protein sequence is 88.4% identical between mouse and human, and most of the differences observed are conservative changes. The proximal Olf-1 binding sites differ by two purine-purine replacements and effectively cross-compete in mobility shift assays. The distal Olf-1 binding site is also highly conserved in terms of both sequence and binding activity. The availability of sequence from multiple species has permitted us to determine that the UBE site has close similarity to motifs that bind members of the NF-1 family of transcription factors. Gel mobility shift assays confirm this prediction, providing additional insight into mechanisms that may participate in the stringent regulation of the expression of this neuronal-specific protein. Furthermore, we demonstrate the in situ localization of OMP mRNA in human olfactory neuro-epithelium and its colocalization to immunocytochemically identified human olfactory receptor neurons.

Amino Acid Sequence↗

PubMed1994

Differential expression of alpha, mu, and pi classes of glutathione S-transferases in chemosensory mucosae of rats during development.

The expression of three classes of glutathione S-transferases (GSTs), Alpha, Mu, and Pi was investigated in the nasal mucosae of rats during development using immunohistochemical methods. GST Alpha and Mu were first detected in the supranuclear region of sustentacular cells on embryonic days 16. The Bowman's glands expressed differential patterns of immunoreactivity during development, beginning at postnatal day (P) 2 and P6 for Alpha and Mu classes, respectively and being greatest at P11 for both. The acinar cells of vomeronasal glands in the vomeronasal organ expressed Alpha and Mu classes of GSTs from P11 onwards. In the septal organ of Masera, the supranuclear region of sustentacular cells expressed GSTs from P11 with little or no variation during development. In the respiratory mucosa, Alpha and Mu classes of GSTs were detected at the brush borders of ciliated cells and in the acinar cells of posterior septal glands, but not in anterior septal or respiratory glands located on the turbinates. Compared to olfactory mucosa, the changes in immunoreactivity for GSTs were less pronounced in the respiratory mucosa during development. Specific GST Pi immunoreactivity was not detected in the nasal mucosae at any stage of development studied. The occurrence of GSTs in the nasal mucosa, including olfactory, vomeronasal, septal, and respiratory epithelia, suggests that the GSTs are actively involved in the biotransformation of xenobiotics including odorants and pheromones, and may also participate in perireceptor processes such as odorant clearance. In addition, we have developed a working model describing the cellular localization of certain phase I (e.g., cytochrome P-450s) and phase II (e.g., GSTs, gamma-glutamyl transpeptidase) biotransformation enzymes in the olfactory mucosa and their proposed roles in xenobiotic metabolism.

Animals↗

PubMed1994

Lectin histochemical localization of galactose, N-acetylgalactosamine, and N-acetylglucosamine in glycoconjugates of the rat vomeronasal organ, with comparison to the olfactory and septal mucosae.

The localization of alpha-D-galactose, N-acetyl-D-galactosamine, and N-acetyl-D-glucosamine sugar residues of glycoconjugates in the vomeronasal organ, olfactory mucosa, and septal organ in the nasal mucosae of rats was investigated using lectinohistochemical techniques combined with bright-field, epifluorescence, and confocal laser scanning microscopy. Glycoconjugates in the mucomicrovillar complex of the vomeronasal organ contained all the sugar residues investigated, whereas glycoconjugates in the mucociliary complex of the olfactory mucosa and septal organ contained only N-acetyl-D-glucosamine. Vomeronasal receptor neurons expressed glycoconjugates with terminal alpha-D-galactose and beta-N-acetyl-D-galactosamine, and N-acetyl-D-glucosamine residues, whereas olfactory and septal receptor neurons expressed glycoconjugates with only N-acetyl-D-glucosamine residues. Secretory granules of glands of the vomeronasal organ contained glycoconjugates with terminal alpha-D-galactose and N-acetyl-D-galactosamine, and N-acetyl-D-glucosamine, whereas those of the Bowman's glands and glands of septal organ contained glycoconjugates with only internal N-acetyl-D-glucosamine residues. The results demonstrate that the glycoconjugates expressed by vomeronasal receptor neurons and glands contain terminal alpha-D-galactose and beta-N-acetyl-D-galactosamine sugar residues that are not expressed by analogous cells in the olfactory mucosa and septal organ.

Acetylgalactosamine↗

PubMed1994

Effects of a carrageenan-induced inflammation in rabbit lumbar facet joint capsule and adjacent tissues.

The effects of experimentally induced inflammation of the lumbar facet joint capsule and adjacent tissues were investigated electrophysiologically and histologically. Type II carrageenan was injected into the receptive fields innervated by identified mechanosensitive afferent units. The multi-unit spontaneous background discharge rate showed increases that consisted of two phases over a time period of 150 min: the first phase (0-30 min) and the second phase (45-150 min). The time course of single units, identified as groups II, III and IV, and silent units, was also investigated. The silent unit discharge rates displayed a gradual increase in the first 15 min and persisted beyond 75 min. Histological examination revealed inflammatory changes in carrageenan injected tissues. In contrast, in isotonic saline injected control experiments there were no changes observed in the electrophysiological or histological studies. This study shows the effects of inflammation in rabbit lumbar facet joint capsule and adjacent tissues. The electrophysiological results show that inflammation of the facet joint and deep back muscles causes (1) increases in multi-unit discharge rate, (2) sensitization to mechanical stimuli and (3) recruitment of previously silent units. Inflammatory changes were also demonstrated histologically.

Animals↗

PubMed1994

Human taste cells express the G protein alpha-gustducin and neuron-specific enolase.

Expression of the alpha-subunit of the taste-specific G protein alpha-gustducin and the glycolytic enzyme neuron-specific enolase (NSE) was investigated immunohistochemically in human circumvallate and foliate taste papillae. Immunofluorescence for alpha-gustducin was observed in taste cells of both types of papillae and exhibited two patterns of immunofluorescence, plasmalemmal and cytosolic. The plasmalemmal pattern showed intense immunofluorescence localized to the apical region, and was exhibited by most immunoreactive taste cells. In contrast, the cytosolic pattern, observed in one or two immunoreactive cells in a taste bud per section, showed immunofluorescence distributed throughout the cytoplasm. A subpopulation of alpha-gustducin-immunoreactive taste receptor cells, most of which exhibited the cytosolic pattern, also expressed NSE. Optical sectioning, using confocal laser scanning microscopy, demonstrated the highest level of expression of alpha-gustducin in the apical microvillar region of the taste cells in close apposition to the taste pore. These studies indicate conservation of epitopes of alpha-gustducin in humans and rats, and suggest that this G protein is associated with taste transduction in both rats and humans. The patterns of expression of alpha-gustducin, and coexpression with NSE, may correlate with specialized subtypes or developmental stages of taste receptor cells.

Aged↗

PubMed1994

Cellular localization of carnosinase in the human nasal mucosa.

The cellular localization of the enzyme carnosinase in human nasal mucosa was investigated using immunoperoxidase and double-staining immunoflourescence techniques. In the olfactory mucosa, carnosinase immunoreactivity was localized in the sustentacular cells, the acinar cells of Bowman's glands, and the perinuclear region of a small subset of olfactory receptor neurons. In the respiratory mucosa, carnosinase immunoreactivity was identified in the secretory vesicles of the epithelial goblet cells as well as in the respiratory glands. There was an age-related trend toward a decrease in the intensity of carnosinase immunoreactivity in the olfactory mucosae of older subjects. These results suggest that the role of carnosinase may be to provide the amino acids histidine and beta-alanine, the products of carnosine hydrolysis, to the amino acid pool for protein synthesis in the cells that secrete nasal mucus and in olfactory receptor neurons.

Adult↗

PubMed1993

Patterns of adrenergic and peptidergic innervation in human olfactory mucosa: age-related trends.

The distribution and targets of nerves containing the adrenergic markers tyrosine hydroxylase, dopamine beta-hydroxylase, and neuropeptide Y in the human olfactory mucosa were investigated by immunohistochemistry. Tissue was obtained at autopsy from the nasal cleft of 16 adults ranging in age from 24 to 90 years, and from one spontaneously aborted 16-week-old fetus. The presence of olfactory receptor neurons in nasal mucosa was confirmed by staining with the antibody to olfactory marker protein. Targets of adrenergic innervation were blood vessels, including the vasa nervorum within the sheaths of olfactory nerve bundles, and Bowman's glands in the lamina propria. Adrenergic fibers penetrated the adventitia of blood vessels and terminated near the media, and were in close proximity to Bowman's glands but did not enter the acini. In the fetal tissue, the vasa nervorum were the major targets of adrenergic fibers. Age-related differences in the pattern and statistically significant differences in the density of innervation of blood vessels were noted between adults under and over 60 years of age. In the younger group, plexuses of nerve fibers containing colocalized dopamine beta-hydroxylase and neuropeptide Y occurred adjacent to arterioles and large bundles of fibers adjacent to venules; in older individuals, few fiber plexuses occurred adjacent to arterioles and thin bundles of fibers adjacent to venules. The distribution of adrenergic innervation suggests that vasomotor tone and secretion are regulated by adrenergic nerves. The decrease in adrenergic innervation in older individuals, with resultant effects on perireceptor processes, may be associated with age-related declines in olfactory function.

Adult↗

PubMed1993

Mucous domains: microchemical heterogeneity in the mucociliary complex of the olfactory epithelium.

Access to and clearance of odorants from binding sites on olfactory cilia are regulated by a complex interplay of molecular, physical and cellular factors. These perireceptor events occur primarily in the mucociliary complex. The use of gold-labelled lectinoprobes, one from Limax flavus (LFA) which is specific for terminal sialic acid residues, and one from Datura stramonium (DSA) specific for N-acetylglucosamine residues, demonstrated intricate patterns of binding in mucous domains of the olfactory mucus and ectodomains of the glycocalyx of olfactory cilia. In electron micrographs of Lowicryl-embedded salamander olfactory mucosa, the mucus consisted of an electron-dense domain that lay superficial to an electron-lucent domain; the interface between the two was irregular. A significantly higher density of binding sites for both lectins was present in the superficial than in the deeper domain. The two domains were not homogeneous: there were small electron-lucent domains (hsL) within the superficial electron-dense domain (hsD) that bound a 4.8-fold lower density of gold-labelled DSA than the surrounding matrix, and the olfactory cilia, which project into hsD, were surrounded by an electron-lucent sheath that appeared to be continuous with the deeper domain. Ectodomains of the glycocalyx associated with olfactory cilia exhibited a higher density of binding sites for both LFA and DSA than did either microvilli of sustentacular cells or respiratory cilia. Specificity of the lectinoprobes was confirmed by inhibition of binding with specific sugars or enzymic removal of specific sugar residues. These results demonstrated microchemical heterogeneity of the non-homogeneous mucous domains in olfactory mucus and in the attendant glycocalyx of olfactory cilia based on the differential localization of sialic acid and N-acetylglucosamine sugar residues.

Animals↗

PubMed1993

Effect of substance P on mechanosensitive units of tissues around and in the lumbar facet joint.

The purpose of this study was to examine how substance P affects the mechanosensitive afferent units identified in the tissues around and in the lumbar facet joint of the rabbit. Substance P was applied to the receptive fields of the units by microinjection, and the afferent activity of the units was recorded from dorsal root filaments. Changes in afferent discharge rates and von Frey thresholds were measured sequentially after the application of substance P. Most of the units (83.3%) had an increase in the ongoing discharge rates after the application of substance P: 54.2% of the units had immediate excitation and 29.2% had delayed excitation. One-third of the units had a decreased von Frey threshold after the application of substance P. Substance P had an excitatory effect on 81.8% of the units with a threshold of > 5.0 g and a conduction velocity of < 30 m/s, which may serve as nociceptors, and on 84.6% of the units with a threshold of < 2.0 g, which may serve as proprioceptors. These results suggest that substance P has an excitatory effect on both nociceptive and proprioceptive units in the tissues around and in the lumbar facet joint.

Animals↗

PubMed1993

Vomeronasal epithelial cells of the adult human express neuron-specific molecules.

Immunohistochemical localization of three molecular markers, neuron-specific enolase (NSE) and protein gene product (PGP) 9.5 for neurons and neuroendocrine cells, and olfactory marker protein (OMP) for olfactory receptor neurons (ORNs) was investigated in the vomeronasal epithelium (VNE) of adult humans. NSE- and PGP 9.5-immunoreactive cells were identified in the VNE. ORNs in the olfactory epithelium of approximately age-matched controls were immunoreactive for the three markers. Most NSE-immunoreactive cells in the VNE were bipolar and similar in shape to the NSE- and PGP 9.5-immunoreactive ORNs. The results indicate that the adult human VNE contains cells expressing two molecular markers characteristic of neurons and that these cells bear a striking morphological similarity to ORNs.

Adult↗

PubMed1993

Expression of a mucociliary-specific epitope in human olfactory epithelium.

An olfactory ciliary-specific epitope was localized immunohistochemically in the mucociliary complex of human olfactory epithelium of 12 subjects ranging in age from 16 weeks of gestation to 85 years, including 3 with Alzheimer's disease. Immunoreactivity for olfactory marker protein (OMP) was used to identify olfactory epithelium; OMP immunoreactivity in olfactory receptor neurons in a 16-week old fetus is the earliest time point at which OMP expression has been detected in human gestation. The results suggest a close coupling between the expression of ciliary molecules associated with odorant transduction and the functional maturation of olfactory receptor neurons.

Adult↗

PubMed1993

Immunohistochemical localization of a cytochrome P-450 isozyme in human nasal mucosa: age-related trends.

Immunoperoxidase staining with an antibody to cytochrome P-450 (NMa) was used to investigate the localization of this isozyme in the human nasal mucosa. Olfactory mucosa was identified by staining of olfactory receptor cells with an antibody to olfactory marker protein. Immunoreactivity to NMa was localized in sustentacular cells in the olfactory epithelium, and in Bowman's gland acinar cells and vascular endothelial cells in the lamina propria. In the respiratory mucosa, ciliated epithelial cells, as well as serous gland acinar cells and vascular endothelial cells in the lamina propria, were immunoreactive for this isozyme. An age-related decrement in the intensity and extent of immunoreactivity within these cells was noted in nasal tissue from patients 60 years of age and over when compared with that of patients under 60 years of age. These results identify sites of xenobiotic metabolism or activation in human nasal mucosa.

Adult↗

PubMed1992

Amphibian olfactory receptor neurons express olfactory marker protein.

Expression of olfactory marker protein (OMP) in olfactory receptor neurons (ORNs) in two amphibians was investigated by immunohistochemical methods. The OMP immunoreactivity was observed in the cilia, apical dendritic knobs, dendrites and somas of ORNs; the axons of ORNs also showed intense immunoreactivity for OMP throughout their course from the olfactory epithelium to the glomerular layer of the olfactory bulb. Seven days after olfactory nerve transection in salamander, the number of OMP-positive ORNs was markedly reduced in the ipsilateral epithelium. The results demonstrate that amphibian ORNs express OMP and confirm its phylogenetic conservation across diverse species.

Ambystoma↗