The microbial ecology and immunology of the adenoid: implications for otitis media.
Department of Otolaryngology, School of Medicine and Biomedical Sciences, State University of New York at Buffalo 14222, USA. Annals of the New York Academy of Sciences
(Impact Factor: 4.38).
The nasopharyngeal tonsil, or adenoid, is a major inductive site for the synthesis of J-chain-positive B cells that may migrate to other areas of the upper respiratory tract, such as the nasal mucosa, the parotid gland, the lacrimal gland, and the middle ear during inflammation. The production of secretory IgA by both the nasopharyngeal tonsil and the nasal mucosa plays a major role in local immune protection against bacteria and viruses. The release of cytokines from Th1 and Th2 lymphocytes must be appropriate for B cells to produce IgA. The factors or mechanisms responsible for this are not, at present, known, but it appears that there is a difference in the profiles of cytokine secretion by Th1 and Th2 lymphocytes in the adenoids in both otitis-prone, as well as nonotitis-prone children. We have suggested that if this specific immune system does not protect the host from invasion by potential pathogens, there are other modalities of therapy to protect the nasopharynx from colonization with pathogenic bacteria or viruses. These include the production of specific antibodies against bacterial surface proteins that have been identified as mucin-binding proteins. Alteration of the microbial flora with commensal organisms such as viridans streptococci can be utilized. These alpha-hemolytic streptococci probably function by producing an acid environment that prevents colonization of organisms such as nontypeable H. influenzae. Finally, the induction of specific SIgA by conserved outer membrane protein antigens of potential pathogens may be another strategy in the prevention of colonization of potential bacterial pathogens in the nasopharynx.
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- "The nasal secretion is a complex mixture of several materials and consists of approximately 95 % water, 2 % mucin, 1 % salts, 1 % of other proteins such as albumin, immunoglobulins , lysozyme and lactoferrin, and 1 % lipids (Kaliner et al 1984). The production of immunoglobulin A by both the adenoid tissue and the nasal mucosa plays a very important role in immune protection against bacteria and viruses (Bernstein et al 1997). The mucus glycoproteins consist of a protein core with oligosaccharide side chains crosslinked by disulphide bridges and hydrogen bonds. "
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ABSTRACT: Nasal drug administration has frequently been proposed as the most feasible alternative to parenteral injections. This is due to the high permeability of the nasal epithelium, allowing a higher molecular mass cut-off at approximately 1000 Da, and the rapid drug absorption rate with plasma drug profiles sometimes almost identical to those from intravenous injections. Despite the potential of nasal drug delivery, it has a number of limitations. In this review, the anatomy and physiology of the nasal cavity, as well as ciliary beating and mucociliary clearance as they relate to nasal drug absorption, are introduced. The rationale for nasal drug delivery and its limitations, some factors that influence nasal drug absorption, and the experimental models used in nasal drug delivery research are also reviewed. Nasal mucoadhesion as a promising method of nasal absorption enhancement is discussed, and factors that influence mucoadhesion, as well as safety of nasal mucoadhesive drug delivery systems are reviewed in detail. Nasal drug administration is presently mostly used for local therapies within the nasal cavity. Anti-allergic drugs and nasal decongestants are the most common examples. However, nasal drug administration for systemic effects has been practised since ancient times. Nasally-administered psychotropic drugs by native Americans, the use of tobacco snuffs, and nasal administration of illicit drugs such as cocaine are all well known (Illum & Davis 1992). Nowadays, the nasal cavity is being actively explored for systemic administration of other therapeutic agents, particularly peptides and proteins (Illum 1992; Edman & Björk 1992), as well as for immunization purposes (Lemoine et al 1998). To better understand the basis for nasal drug absorption and factors that can influence it, a brief review of the anatomy and physiology of the nose is appropriate.
Available from: Albert Navarro
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ABSTRACT: Although the aetiology of otitis media is known to be multifactorial, adenoids infections and Eustachian tube dysfunction, have been frequently associated with the incidence of middle-ear effusion. Middle-ear effusion cases are frequent in Maputo, Mozambique, and very often insertion of tympanostomy tubes and adenoidectomy alone or with amigdalectomy have been used to treat these cases and to prevent further episodes. The objective of this study is to describe the association of these factors with otitis medias with effusion in patients that visit the Otorrinolaringology department (ENT) at the Central Hospital of Maputo (HCM), as well as to describe the clinical and epidemiological profile of these patients.
A cross sectional study was conducted. 4157 clinical files of all patients who made their first visit to the ENT department at the HCM, with otitis media during a period of 4 years (1995 to 1998).
23.3% of patients who visited the ORL service of Maputo with otitis media, are children under 3 years; the major proportion of otitis media with effusion was observed in children aged from 3 to 7 years old (49.2%). In boys under, otitis media with effusion is strongly associated with the history of adenoiditis and/or Eustachian tube dysfunction (OR=9.53) and in older patients (OR=12.26).
The proportion of otitis media with effusion increases more evidently in patients with disfuntion tube syndrome. Other factor that can be important in patients under seven, is the presence of adenoiditis.
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ABSTRACT: The role of viridans group streptococci (Streptococcus oralis) in the prevention of colonization with nontypeable Haemophilus influenzae and Moraxella catarrhalis was investigated in an adenoid organ culture system. The adenoids from 100 patients who were undergoing adenoidectomy for either hypertrophy or recurrent otitis media were used. Streptococcus oralis Parker uniformly inhibited colonization with nontypeable H. influenzae or M. catarrhalis over a 24-hour period of incubation in adenoid organ culture. Streptococcus oralis Booth, a noninhibitory strain, did not significantly reduce colonization with nontypeable H. influenzae and M. catarrhalis. The results indicate that some strains of S. oralis may inhibit colonization with potential pathogens in the nasopharynx. It is therefore possible that colonization with inhibitory strains of viridans streptococci may be used in the nasopharynx as a relatively safe and inexpensive approach to prevention of recurrent otitis media in some children.
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