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PubMed2002

Parenteral vaccination against influenza does not induce a local antigen-specific immune response in the nasal mucosa.

The immune response in the nasal mucosa to influenza vaccination in 23 patients scheduled for tonsillectomy was studied. A statistically significant increase in influenza virus-specific serum and oral fluid antibodies was observed 7 days after vaccination. The numbers of influenza virus-specific antibody-secreting cells (ASCs) in peripheral blood also increased significantly 1 week after vaccination. The numbers of ASCs in tonsils and nasal mucosa were compared with data from a recent study of nonvaccinated volunteers. The numbers of influenza virus-specific ASCs in tonsils were significantly higher in the vaccinated group, but, surprisingly, there was no significant difference between the groups in the numbers of ASCs in nasal mucosa. This suggests that the influenza virus-specific antibodies detected in oral fluid are not produced locally in the nasal mucosa and may originate from a systemic source, indicating that the vaccination may favor a systemic immune response.

Adult↗

PubMed1998

Histochemical and immunohistochemical studies of distribution of acetylcholinesterase-positive fibers and peptidergic terminals in the nasal mucosa of rats.

OBJECTIVE: To further investigate the mechanism of nasal secretion closely related to the innervation patterns in nasal mucosa with emphasis on the acetylcholinesterase (AChE)-positive fibers and peptidergic terminals in nasal mucosa as well as trigeminal ganglion (TG) cells. METHODS: Histochemical demonstration of AChE-positive fibers, immunohistochemical study of the distribution patterns of multiple peptidergic terminals, double labelling of AChE and substance P (SP) and somatostatin (SOM) mRNA in situ hybridization were carried out in nasal mucosa and trigeminal ganglion (TG) in rats. RESULTS: AChE-positive terminals were mainly distributed in the mid to posterior one third of septal nasal mucosa, with greater staining density on the walls of small vessels and glands. There were fewer such terminals in turbinate mucosa. Tachykinins-ergic terminals, including substance P (SP)-, neurokinin A (NKA)-, neurokinin B (NKB)- and calcitonin gene-related peptide (CGRP)-ergic terminals, had an extensive localizations in nasal mucosa, involving the following areas: between epithelial cells, submucosa, the walls of small vessels, glands and venous sinusoids in both septal and turbinate nasal mucosa. Septal mucosa had the greater density. There were overlaps in the distribution of these peptidergic terminals. There were also vasoactive intestinal peptide (VIP)-, neuropeptide Y (NPY)- and galanin (GAL)-ergic terminals in nasal mucosa. But no neurotensin (NT)- and somatostatin (SOM)-ergic terminals were found. In situ hybridization revealed SOMmRNA expression in TG cells. AChE and nine neuropeptides existed in the cytoplasms of TG cells. Besides, AChE and SP could exist simultaneously in cytoplasms of TG cells. CONCLUSIONS: AChE-positive (corresponding to parasympathetic nerves) and peptidergic terminals have different distribution patterns in the nasal mucosa of rats, although an overlap does exist, indicative of their different physiological effects on the regulation of nasal secretion and other functions; AChE and multiple neuropeptides in the cytoplasm of TG cells might play a role in modulating the nasal secretion in response to stimuli in the nasal mucosa.

Acetylcholinesterase↗

PubMed1992

Immunohistochemical detection of serous cells in nasal mucosa with monoclonal antibody against a component in human nasal secretion.

Secreting mechanisms of secretory cells in nasal mucosa and the changes of nasal secretions in chronic inflammatory sinusitis have been studied by the biochemical and histochemical methods. These methods could not clarify the changes of quality and quantity of nasal secretions and secretory cells. In order to obtain the specific marker for the secretions in different cells, we have produced monoclonal antibodies against a component in human nasal discharge. One antibody was selected for further characterization, because it stained submucosal serous cells specifically. This antibody stained the components of serous cells with molecular weight of 14 kD specifically, and was sensitive to periodate oxidation treatment. This antibody will be useful for detecting the subpopulation in secretory cells of human nasal mucosa, and may be serve as a biochemical probe for secretory activity of particular secretory cell types.

Antibodies, Monoclonal↗

PubMed1999

[Immunohistochemical study of the distribution of constitutive nitric oxide synthase in vascular endothelium of the nasal mucosa in the human].

BACKGROUND: Human nasal mucosa is a highly regulated tissue that performs a wide range of physiological functions. In addition to the classic and peptidergic neurotransmitters, the endogenously produced free radical gas nitric oxide (NO) has been found to be increasingly important for the vascular regulation of this tissue. NO-dependent control of vascular tone works in two ways, consisting of neurally produced NO acting as a neurotransmitter on the one hand and endothelially produced NO on the other hand. Neurons and endothelial cells contain various isoforms of the enzyme nitric oxide synthase, which forms NO out of L-arginine. The aim of this study was to examine the distribution of endothelial constitutive NO-synthase (ecNOS) in the human nasal mucosa of inferior turbinates. METHODS: Immunocytochemistry (avidin-biotin method) with polyclonal and monoclonal antibodies against eNOS and cluster of differentiation 31, a marker for endothelial and certain blood cells, was used in order to gain more detailed information on the physiological distribution and significance of NOS in vascular endothelium of different vessel types. RESULTS: Positive eNOS-immunoreactions were found in the endothelial cells of arterial blood vessels of different diameters as well as in capillaries and postcapillary venules. Venous sinuses with or without subendothelial cushions did not show any immunoreactions. CONCLUSIONS: There is strong evidence that vascular tone in human nasal mucosa is not only subject to nerval control, but also influenced directly by mediators released from the endothelium. The present results lead to the conclusion that in physiological conditions endothelially produced NO has an influence on the arterial component of the swelling mechanism in human nasal mucosa. Because eNOS could also be detected in capillaries and postcapillary venules, NO might also play an important role in plasma extravasation.

Adult↗

PubMed1999

Histamine H1 receptor and reactivity of the nasal mucosa in sensitized guinea pigs.

OBJECTIVE: Nasal Hypersensitivity to histamine is higher in allergic patients than that in normal control, suggesting that affinity and/or density of H1 receptors in nasal mucosa may be increased in patients with allergic rhinitis. The purpose in this study is to examine the correlation between the hyperresponsiveness and number of histamine H1 receptors in guinea pig nasal mucosa. METHODS: Guinea pigs were sensitized by DNP-Ascaris antigen. To block histamine H1 receptors, ketotifen was used and the number of receptors was counted by receptor binding assay technique. These data were compared with nasal airway volume (VOL) assessed by acoustic rhinometry of the same animals to know whether the number of H1 receptors is correlated to the nasal responsiveness to the antigen, or not. Eighty animals were divided into five groups which are composed of nonsensitized and sensitized group pretreated with saline, 0.1, 1.0 and 10 mg/kg of ketotifen, respectively. RESULTS: The number of H1 receptors (Bmax) was significantly increased in sensitized group compared with that in control. It decreased dose dependently by pretreatment of ketotifen. The percent change of VOL showed - 31.1 +/- 4.1% at 10 min and - 42.9 +/- 4.1% at 30 min after antigen challenge in sensitized animals. This was dose dependently inhibited by ketotifen. There was a highly inverse correlation between VOL and Bmax (r = -0.708, P< 0.0001). CONCLUSION: These results suggest that sensitization increases the number of histamine H1 receptor, and that increased number of H1 receptor in nasal mucosa in sensitized guinea pigs may be one of the causes of nasal hyperresponsiveness to antigen.

Administration, Oral↗

PubMed1990

Characterization and quantification of cellular infiltrates in nasal mucosa of patients with grass pollen allergy, non-allergic patients with nasal polyps and controls.

Little is known about cellular infiltrates in nasal mucosa and the differences between these infiltrates in allergic and non-allergic patients. A reproducible and objective method making use of monoclonal antibodies for the quantification and characterization of cellular infiltrates in biopsy specimens of nasal mucosa is described. This method was used to study quantitative differences in cellular infiltrates in the epithelium and lamina propria of the nasal mucosa of patients with isolated grass pollen allergy, non-allergic patients with nasal polyps, and controls. A surprisingly wide variation was found in all groups. In all groups the T lymphocytes were much more numerous than the B lymphocytes. The number of CD8+ cells exceeded the number of CD4+ cells in the epithelium but in the lamina propria the numbers were approximately equal. Significant differences between the three groups were found with respect to the number of CD1+, IgE+, neutrophils and cytoplasmic IgG4+ cells. No significant differences were found in the numbers of CD4+, CD8+, CD14+, CD22+, HLA-DR+, IgG1-3+ cells or eosinophils. The use of biopsy in combination with monoclonal antibodies is an easy and well-tolerated method to study immunological reactions in the nasal mucosa. The results of this study indicate a possible role for a T-cell-mediated response in allergic rhinitis.

Antibodies, Monoclonal↗

PubMed2001

Effect of budesonide and nedocromil sodium on IL-6 and IL-8 release from human nasal mucosa and polyp epithelial cells.

We investigated the effect of budesonide and nedocromil sodium on the secretion of IL-6 and IL-8 by cultured epithelial cells from healthy nasal mucosa and nasal polyps. Human epithelial cell conditioned media was generated with fetal calf serum (FCS) in the presence or absence of budesonide and/or nedocromil sodium. Budesonide inhibited FCS-induced IL-6 and IL-8 release in a dose-dependent manner. The IC25 (25% inhibitory concentration) of budesonide on IL-6 release was higher in nasal polyp than in nasal mucosa epithelial cells (34 nM vs. 200 pM). The IC25 of budesonide on IL-8 release was higher in nasal mucosa than in nasal polyps (145 pM vs. 4 pM). Nedocromil sodium caused a dose-related inhibitory effect on IL-8 release from nasal mucosa (IC25, 207 nM), while it only had a significant effect in nasal polyps at 10(-5) M. Nedocromil sodium had no effect on IL-6 release. The inhibitory effect of budesonide was higher than that of nedocromil sodium on both nasal polyps and nasal mucosa. Budesonide and nedocromil sodium may exert their anti-inflammatory action in the respiratory mucosa by modulating the secretion of IL-6 and IL-8. The different effect of budesonide and nedocromil sodium on IL-6 and IL-8 release may be explained by differences in the mechanisms which regulate the upregulation of these cytokines in inflammatory responses.

Adolescent↗

PubMed2002

Antimicrobial defensin peptides of the human nasal mucosa.

Defensins, a prominent group of antimicrobial peptides, are an important component of the innate immune response, particularly at mucosal surfaces that are vulnerable to colonization by potential pathogens. The present study was undertaken to investigate the expression of defensins in inferior turbinate mucosa of normal subjects and inferior turbinate mucosa and nasal polyps of patients with chronic sinusitis. Expression of beta-defensin 1 and 2 and alpha-defensin 5 and 6 messenger RNAs (mRNAs) was investigated by reverse transcriptase-polymerase chain reaction, and their expression level was semiquantitatively evaluated by dot blot hybridization. Immunohistochemical analysis was used for detection of alpha-defensins 1, 2, and 3 in tissue sections. Beta-defensin 1 mRNA was expressed in all tissue samples, at levels that did not differ significantly. Beta-defensin 2 mRNA was detected in the turbinate mucosa and nasal polyps of patients with chronic sinusitis, but not in normal mucosa. Its expression level was significantly higher in nasal polyps than in turbinate mucosa. Alpha-defensin 5 and 6 mRNAs were not expressed in any tissues, but alpha-defensins 1, 2, and 3 were detected in all tissue samples obtained from patients with chronic sinusitis. These results suggest that beta-defensin 1 may play a constitutive role in nasal defenses, whereas alpha-defensins 1, 2, and 3 and beta-defensin 2 may be induced in response to local infection or inflammation.

Adult↗

PubMed2000

Fine-structural investigations of the effect of nCPAP-mask application on the nasal mucosa.

The treatment success of nasal continuous positive airway pressure (nCPAP)-therapy is dependent, on the one hand, on the achieved relief of complaints and, on the other hand, on long-term patient compliance and avoidance of compliance-related complaints. Next to the problem of mask application, nasal complaints comprise the most frequently reported side-effects and are among the primary factors causing nCPAP-therapy to be discontinued prematurely. To assess the morphological changes in the nasal mucosa during nCPAP-therapy, we excised specimens of nasal mucosa tissue from 10 patients with obstructive sleep apnoea syndrome (OSAS) before and 3-10 months after establishing nCPAP-mask compliance. The specimens were examined by electron microscopy. In all these patients compliance with the CPAP-mask marked the initial part of therapy. In addition, mucociliary clearance was assessed by the saccharin test before and after therapy. In all patients the nasal epithelium underwent fundamental changes upon CPAP-therapy, which became manifest as modifications in the shape of epithelial cells, conglutination and clumping of the microvilli, and the appearance of immunocompetent cells. Once patients were nCPAP-mask compliant, mucociliary clearance was distinctly prolonged in all cases. A successful therapeutic concept should provide normalization of room temperature and air humidity once nCPAP-mask compliance has been achieved and include regular assessment of the condition of the mucosa in the upper respiratory tract. Only by these measures can nasal complications be countered or given therapy at an early stage.

Adult↗

PubMedDate not supplied

Effect of snuff on nasal mucosa.

PURPOSE: The inhalation of nasal snuff (powdered tobacco) is a common addiction in the Indian subcontinent. In the western world, there is a resurgence of interest in nasal snuff because it does have the morbidity associated with smoked tobacco. Very few studies have reported the long-term effects of snuff on nasal mucosa. The objective of the present study was to investigate the effect of long-term use of snuff on the nasal mucosa. MATERIALS AND METHODS: We conducted a retrospective study on 29 snuff users. We investigated the reasons for initiation of this particular form of addiction along with the clinical signs and symptoms of long-term snuff usage. At the time of the study, all patients complained of one or more nasal symptoms. Nasal obstruction and nasal discharge taken together were reported by 62.5% of patients. Gross mucosal edema of the septum and turbinates was the main finding on nasal examination. The absolute eosinophil count and total serum immunoglobulin E were elevated in 62.5% and 66.7% of patients, respectively. On skin prick test, 41% of patients reacted positively to snuff and 25% to tobacco. Histopathologic examination of the turbinates (16 patients) showed squamous metaplasia, capillary proliferation, capillary and venous dilatation, inflammatory cell reaction, subepithelial edema, and fibrosis. CONCLUSIONS: Much has been written about the advantages of nasal snuff over products that deliver tobacco smoke. Our study shows that snuff users, after long-term abuse, develop a form of chronic rhinitis, as a consequence of which they develop blocked and stuffy noses. We conclude that nasal snuff is not a suitable substitute for smoked tobacco because it does not avoid ill health.

Adult↗

PubMed1981

Sympathetic innervation of the nasal mucosa of the pig.

Nasal disorders such as atrophic rhinitis in the pig are widespread and are of economic importance in livestock production. A better understanding of the basic physiology of the nasal mucosa could help in the study and treatment of nasal disorders. This paper presents a simple method which may prove useful in studies on the autonomic innervation of the nasal blood vessels. The results demonstrate the great sensitivity of the nasal blood vessels to sympathetic activity and indicate that there may be a vascular connection between the two nasal passages.

Animals↗

PubMed1998

The long-term effects of capsaicin aqueous spray on the nasal mucosa.

BACKGROUND: Capsaicin has been shown previously to reduce nasal complaints in patients with a non-allergic non-infectious perennial rhinitis. Proposed pathophysiological mechanisms for non-allergic non-infectious perennial rhinitis include a chronic inflammatory disorder of an antigenic or neurogenic nature as well as the possibility of a functional neuronal disorder. We hypothesized that the beneficial effect of capsaicin might be the result of a down-regulation of inflammation (by a reduction of inflammatory cells) or through modulation of neural tissue density. METHODS: Patients were treated with either a placebo or capsaicin spray solution delivering 0.15 mg of capsaicin per nostril once every second or third day for a total of seven treatments. Both sides were treated each visit. Biopsies were taken before and 2 weeks, 3 months and 9 months after the treatment period. Immunohistochemical staining of the biopsy specimen was performed to ascertain the effect of treatment on immunocompetent cell densities (quantitative) and neural tissue densities (semi-quantitative) in the nasal mucosa. RESULTS: Nasal complaints were significantly reduced in the capsaicin-treated group. The number of CD1+, CD25+, CD3+, CD68+, BMK13+, IgE+, tryptase+, and chymase+ cells did not significantly differ between capsaicin and placebo group. No significant differences between both groups were found in pan-neurogenic staining of nasal mucosa using neurofilament and synaptophysine. CONCLUSION: Capsaicin aqueous nasal spray has previously been shown to reduce nasal complaints without affecting cellular homeostasis or overall neurogenic staining up to 9 months after treatment. Immunocompetent cells are not involved in non-allergic non-infectious perennial rhinitis.

Administration, Intranasal↗

PubMed1989

Beneficial effect of capsaicin application to the nasal mucosa in cluster headache.

Capsaicin application to human nasal mucosa was found to induce painful sensation, sneezing, and nasal secretion. All of these factors exhibit desensitization upon repeated applications. The acute effects induced by capsaicin (300 micrograms/100 microliters) application to the nasal mucosa were studied in healthy volunteers and cluster headache patients. These effects were not different in both nostrils of cluster headache patients as well as in the single nostril of healthy controls. Likewise, the time course of desensitization to the painful sensation and nasal secretion induced by capsaicin applied for five consecutive days in control subjects was almost superimposable to those observed in the nasal mucosa of cluster headache patients. The number of spontaneously occurring attacks was significantly reduced in the 60 days after the end of capsaicin treatment. Whether the beneficial effect induced by capsaicin application to the nasal mucosa could be ascribed to a specific action on sensory neurons remains unknown.

Administration, Intranasal↗

PubMed1998

Cold exposure enhances nitroxidergic nerve-mediated vasodilatation in canine nasal mucosa.

We have previously reported that there is non-adrenergic, non-cholinergic (NANC) innervation in canine nasal mucosa and that the relaxation response to electrical stimulation of the NANC nerve is mainly mediated by nitric oxide (NO). In the present study, we examined the effect of cold exposure (24 degrees C) on nitroxidergic nerve-mediated vasodilatation in isolated canine nasal mucosa. Nasal mucosa strips, prepared from canine nasal septum and moderately precontracted with methoxamine in the presence of atropine and guanethidine, relaxed in response to transmural electrical stimulation (square pulses of 0.5-msec duration, at 5 Hz and 25 V). The degree of relaxation at 24 degrees C (55.4+/-13.2% of methoxamine-induced contraction, mean+/-S.D., n=6) was significantly greater than that at 34 degrees C (33.8+/-8.6%, n=6). This phenomenon was reversible. In contrast, the magnitude of relaxation responses to an NO donor (sodium nitroprusside of 0.1 and 1 microM) remained unchanged by cold exposure. These results suggest that the release of NO from the nitroxidergic nerve endings is augmented by cold exposure and, thus, vasodilatation of the nasal blood vessel is enhanced, thereby contributing to the swelling of the nasal mucosa in cold conditions.

Animals↗

PubMed2000

Effect of starvation and chlormethiazole on cytochrome P450s of rat nasal mucosa.

Cytochrome P450 (CYP) enzymes of nasal tissue are relatively resistant to induction by classical inducers. In the present study, the effects of starvation on the expression of CYP1A, 2A, 2B, 2C, 2E, 2G, and 3A subfamilies in the nasal mucosa of rat were studied. Fasting for 72 hr caused an increase in 2E1-dependent p-nitrophenol hydroxylase and 1A-dependent ethoxy- (or methoxy) resorufin dealkylase activities, but did not affect either 2A-linked coumarin hydroxylase or the testosterone hydroxylase activity, the latter reaction being a marker of several CYPs including 2G1. Whereas increases in 2E1- and 1A- associated catalytic activities were accompanied by a concomitant increase in the corresponding apoproteins as determined by immunoblotting, immunoactive protein bands reactive with antibodies raised against rat 1A1, 2B1, 2C11, 3A1 or rabbit nasal 2A10/11 and 2G1 were not altered. Fasting also increased CYP2E1 and CYP1A2 on the mRNA level, but did not alter CYP1A1 mRNA as determined by hybridization with cDNA probes selective for these cytochromes. A reiterative administration of chlormethiazole, a specific inhibitor of 2E1 in liver, strongly inhibited many CYPs, including 2E1, 1A2, 2G1, and 2A in the nasal mucosa, but did not influence expression of 2B or 3A as determined by immunoblotting or catalytic activities. The chlormethiazole-mediated inhibition of 1A1 and 2E1 was demonstrated to be at the mRNA level. These results suggest that fasting induces the gene expression of 2E1 and 1A2 and that the mechanisms involved in the regulation of CYPs in the nasal mucosa are tissue-specific. The inducibility of the above-mentioned isoforms may have a significant role in the clearance of drugs and bioactivation of inhaled compounds.

Animals↗

PubMed2003

Local somatic hypermutation and class switch recombination in the nasal mucosa of allergic rhinitis patients.

Immunoglobulin E is produced by nasal B cells in response to allergen. We have analyzed IgE V(H) region sequences expressed in the nasal mucosa of patients suffering from allergic rhinitis. V(H) region sequences were amplified by RT-PCR from IgE(+) B cells from nasal biopsies. In two of six patients, sequence analysis clearly demonstrated the presence of closely related IgE(+) B cell clones: cells displaying identical signature regions across CDR3/FWR4, indicating a common clonal ancestry, but a mixture of shared and diverse somatic mutations across the V(H) region. Furthermore, in one of the two patients exhibiting related IgE(+) B cell clones, five IgA(+) B cell clones, related to the IgE(+) B cell family, were also isolated from the patient's nasal mucosa. This evidence, combined with the local expression of mRNA transcripts encoding activation-induced cytidine deaminase, suggests that local somatic hypermutation, clonal expansion, and class switch recombination occur within the nasal mucosa of allergic rhinitics. The presence of related B cells in the nasal mucosa does not appear to result from the random migration of IgE(+) cells from the systemic pool, as analysis of a nonatopic subject with highly elevated serum IgE did not exhibit any detectable V(H)-Cepsilon transcripts in the nasal mucosa. We have provided evidence that suggests for the first time that the nasal mucosa of allergic rhinitics is an active site for local somatic hypermutation, clonal expansion, and class switch recombination, making it of major significance for the targeting of future therapies.

Adolescent↗

PubMedDate not supplied

The ultrastructure of nasal mucosa in children with asthma.

Nasal brushing has sometimes been used to characterize some affections of the respiratory tract, but seldom employed in chronic diseases such as asthma, for the possible presence of cellular inflammation in the small specimens used for electron microscopy. The present study evaluated the ultrastructure of epithelial cells obtained by nasal brushing in 11 allergic children with asthma, before and after staying in an environment free of allergens, usually implicated in the genesis of inflammatory events. The ultrastructural alterations of the nasal mucosa have been graded on the basis of their severity. Grade I lesions were characterized by well-differentiated mucous and ciliated cells. The ciliated cells appeared usually well preserved but decreased in number. In grade II lesions, most of the epithelial surface was covered by mucous cells. A further phenotype composed of poorly differentiated ciliated or mucous cells was detected. Grade III lesions showed aspects of depletion of the ciliated and mucous cells. The epithelium was largely composed of undifferentiated cells. Furthermore, the comparison of specimens at 2 different times of sampling did not differ. The data demonstrate that in allergic children with asthma, the nasal mucosa showed ultrastructural changes, which appeared to be unmodifiable during a prolonged stay in an environment free of allergens. Moreover, the nasal epithelium may provide a convenient sampling site, allowing grade of mucosal damage, with the benefit that the brush method is minimally invasive and avoids complications related to bronchoscopic examination.

Allergens↗

PubMed1991

Metabolism of carcinogenic nitrosamines by rat nasal mucosa and the effect of diallyl sulfide.

Rat nasal cavity is one of the target organs for carcinogenesis induced by N-nitrosodimethylamine (NDMA), N-nitrosodiethylamine (NDEA), and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). The present work investigated the metabolism of these nitrosamines by rat nasal microsomes, as well as the possible modulating factors. Microsomes prepared from rat nasal mucosa were efficient in metabolizing these nitrosamines. In general, the metabolism of the nitrosamines was slightly higher in 9-week-old rats than in 4-week-old animals, and there was no sex-related difference. Fasting of rats for 48 h, which is known to induce hepatic cytochrome P450IIE1 and NDMA metabolism, did not increase the nasal metabolism of NDMA, NDEA, or NNK. Pretreatment of rats with acetone, another inducer of hepatic P450IIE1, did not increase the metabolism of NDMA. Furthermore, it decreased the nasal metabolism of NDEA and NNK. Immunoinhibition studies suggest that, in the nasal mucosa, P450IIE1 is only partially responsible for the oxidation of NDMA and other P450 isozymes are responsible for the metabolism of NDEA. A single p.o. pretreatment of male rats with diallyl sulfide (DAS), a component of garlic oil, caused a significant decrease in the oxidative metabolism of NDEA and NNK in rat nasal mucosa. Whereas the nasal metabolism of NDMA was reduced by DAS pretreatment, there was no change in the amount of the nasal microsomal proteins immunoreactive with the antibodies against P450IIE1. The inhibitory effect of DAS on the nasal oxidative metabolism of NDMA, NDEA, and NNK was also observed in experiments in vitro. The results demonstrate the ability of nasal mucosa to metabolically activate these nitrosamines and the inhibition of this process by DAS, suggesting that DAS may be effective in inhibiting the related nasal tumorigenesis.

Acetone↗