Kinetic and frequency-domain properties of reflex and conditioned eyelid responses in the rabbit. (33/1321)

Eyelid position and the electromyographic activity of the orbicularis oculi muscle were recorded unilaterally in rabbits during reflex and conditioned blinks. Air-puff-evoked blinks consisted of a fast downward phase followed sometimes by successive downward sags. The reopening phase had a much longer duration and slower peak velocity. Onset latency, maximum amplitude, peak velocity, and rise time of reflex blinks depended on the intensity and duration of the air puff-evoking stimulus. A flashlight focused on the eye also evoked reflex blinks, but not flashes of light, or tones. Both delayed and trace classical conditioning paradigms were used. For delayed conditioning, animals were presented with a 350-ms, 90-dB, 600-Hz tone, as conditioned stimulus (CS). For trace conditioning, animals were presented with a 10-ms, 1-k/cm(2) air puff, as CS. The unconditioned stimulus (US) consisted of a 100-ms, 3-k/cm(2) air puff. The stimulus interval between CS and US onsets was 250 ms. Conditioned responses (CRs) to tones were composed of downward sags that increased in number through the successive conditioning sessions. The onset latency of the CR decreased across conditioning at the same time as its maximum amplitude and its peak velocity increased, but the time-to-peak of the CR remained unaltered. The topography of CRs evoked by short, weak air puffs as the CS showed three different components: the alpha response to the CS, the CR, and the reflex response to the US. Through conditioning, CRs showed a decrease in onset latency, and an increase in maximum amplitude and peak velocity. The time-to-peak of the CR remained unchanged. A power spectrum analysis of reflex and conditioned blink acceleration profiles showed a significant approximately 8-Hz oscillation within a broadband of frequencies between 4 and 15 Hz. Nose and mandible movements presented power spectrum profiles different from those characterizing reflex and conditioned blinks. It is concluded that eyelid reflex responses in the rabbit present significant differences from CRs in their profiles and metric properties, suggesting different neural origins, but that a common approximately 8-Hz neural oscillator underlies lid motor performance. According to available data, the frequency of this putative oscillator seems to be related to the species size.  (+info)

Construction and characterization of a Salmonella enterica serovar typhimurium clone expressing a salivary adhesin of Streptococcus mutans under control of the anaerobically inducible nirB promoter. (34/1321)

Attenuated Salmonella enterica serovar Typhimurium has been used for targeted delivery of recombinant antigens to the gut-associated lymphoid tissues. One potential problem associated with this vaccine approach is the likelihood of in vivo instability of the plasmid constructs caused by constitutive hyperexpression of the heterologous immunogen. The aim of this study was to generate and characterize an expression system encoding the saliva-binding region (SBR) of Streptococcus mutans antigen I/II adhesin, either alone or linked with the mucosal adjuvant cholera toxin A2/B subunits (CTA2/B), under the control of the inducible nirB promoter. This promoter is activated in an anaerobic environment and within macrophages, which are the primary antigen-presenting cells involved in phagocytosis and processing of Salmonella. The gene encoding the chimeric SBR-CTA2/B was amplified by PCR using primers containing appropriate restriction sites for subcloning into pTETnirB, which contains the nirB promoter. The resulting plasmid was introduced into serovar Typhimurium by electroporation. Production of the SBR-CTA2/B chimeric protein under anaerobic conditions was verified by enzyme-linked immunosorbent assay of whole-cell lysates on plates coated with G(M1) ganglioside and developed with antibodies to SBR. Similar procedures were followed for cloning the gene encoding SBR in serovar Typhimurium under nirB control. Anaerobic expression of SBR was confirmed by Western blotting of whole-cell lysates probed with anti-SBR antibodies. The resulting serovar Typhimurium strains were administered by either the oral or the intranasal route to mice, and colonization was assessed by microbiologic analysis of dissociated spleens, Peyer's patches (PP), and nasal tissues. High numbers of the recombinant strains persisted in PP and spleen for at least 21 days following oral challenge. A single intranasal administration of the Salmonella clones to mice also resulted in the colonization of the nasal tissues by the recombinant bacteria. Salmonellae were recovered from nasal lymphoid tissues, superficial lymph nodes, internal jugular lymph nodes, PP, and spleens of mice for at least 21 days after challenge. This study provides quantitative evidence for colonization by Salmonella strains expressing a recombinant protein under the control of the inducible nirB promoter in PP or nasal tissues following a single oral or nasal administration of the bacteria, respectively.  (+info)

Midline destructive lesions of the sinonasal tract: simplified terminology based on histopathologic criteria. (35/1321)

BACKGROUND AND PURPOSE: Destructive lesions of the sinonasal tract, lacking a discernible etiology and referred to as midline destructive disease, have been pathologically classified in accordance with a variety of confusing terms. Development of new pathologic concepts and immunohistochemical techniques has provided a fresh understanding of these lesions, and, as a result, they can be unified into two distinct pathologic groups: Wegener's granulomatosis and non-Hodgkin's T-cell lymphoma. METHODS: We retrospectively reviewed the imaging studies and pathologic specimens of seven patients with prior diagnoses included in the midline destructive disease group. The specimens were reviewed by an oral pathologist using currently accepted pathologic criteria and the newly available immunohistochemical markers CD20, CD45, and CD45RO. Lesions were classified as non-Hodgkin's T-cell lymphomas when positive for CD45 and CD45RO and negative for CD20, and as Wegener's granulomatosis in the presence of noncaseating multinucleated giant cell granulomas and necrotizing vasculitis. RESULTS: Three of the lesions were reclassified as Wegener's granulomatosis and four as T-cell lymphomas after applying these pathologic criteria. There were no distinguishing imaging findings between Wegener's granulomatosis and non-Hodgkin's T-cell lymphoma. CONCLUSION: The current pathologic classification for midline destructive disease should be incorporated into the radiologic lexicon and the use of terms from the old classification system, such as idiopathic midline granuloma and lethal midline granuloma, should be abandoned and no longer be used in radiologic reports.  (+info)

Macroporous polymer foams by hydrocarbon templating. (36/1321)

Porous polymeric media (polymer foams) are utilized in a wide range of applications, such as thermal and mechanical insulators, solid supports for catalysis, and medical devices. A process for the production of polymer foams has been developed. This process, which is applicable to a wide range of polymers, uses a hydrocarbon particulate phase as a template for the precipitation of the polymer phase and subsequent pore formation. The use of a hydrocarbon template allows for enhanced control over pore structure, porosity, and other structural and bulk characteristics of the polymer foam. Polymer foams with densities as low as 120 mg/cc, porosity as high as 87%, and high surface areas (20 m(2)/g) have been produced. Foams of poly(l-lactic acid), a biodegradable polymer, produced by this process have been used to engineer a variety of different structures, including tissues with complex geometries such as in the likeness of a human nose.  (+info)

Asymptomatic intranasal abnormalities influencing the choice of nostril for nasotracheal intubation. (37/1321)

We have studied the prevalence of intranasal abnormalities that may influence the choice of nostril for intubation, using the fibreoptic laryngoscope, in 60 oral surgery patients presenting for nasotracheal intubation under general anaesthesia, who had no symptoms or signs of nasal obstruction. Videotape recordings were made during each nasendoscopy and later analysed by an anaesthetist and an otolaryngologist. A total of 68% of patients had intranasal abnormalities (10% bilateral and 58% unilateral) which resulted in one nostril being more patent than the other and therefore considered more suitable for intubation. The most common abnormality was deviated nasal septum which occurred in 57% of the study group; 22% were minor deviations, 13% were major deviations and 22% were impactions. Other abnormalities were simple spurs, unilateral polyp and hypertrophy of the inferior turbinate. In view of the relatively high incidence of intranasal pathology revealed on endoscopic examination, anaesthetists should consider using the fibreoptic laryngoscope to select the best nostril when performing nasotracheal intubation.  (+info)

Role of Bordetella bronchiseptica fimbriae in tracheal colonization and development of a humoral immune response. (38/1321)

Fimbriae are filamentous, cell surface structures which have been proposed to mediate attachment of Bordetella species to respiratory epithelium. Bordetella bronchiseptica has four known fimbrial genes: fim2, fim3, fimX, and fimA. While these genes are unlinked on the chromosome, their protein products are assembled and secreted by a single apparatus encoded by the fimBCD locus. The fimBCD locus is embedded within the fha operon, whose genes encode another putative adhesin, filamentous hemagglutinin (FHA). We have constructed a Fim(-) B. bronchiseptica strain, RB63, by introducing an in-frame deletion extending from fimB through fimD. Western blot analysis showed that RB63 is unable to synthesize fimbriae but is unaffected for FHA expression. Using this mutant, we assessed the role of fimbriae in pathogenesis in vitro and in vivo in natural animal hosts. Although RB63 was not significantly defective in its ability to adhere to various tissue culture cell lines, including human laryngeal HEp-2 cells, it was considerably altered in its ability to cause respiratory tract infections in rats. The number of DeltafimBCD bacteria recovered from the rat trachea at 10 days postinoculation was significantly decreased compared to that of wild-type B. bronchiseptica and was below the limit of detection at 30 and 60 days postinoculation. The number of bacteria recovered from the nasal cavity and larynx was not significantly different between RB63 and the wild-type strain at any time point. The ability of fimbriae to mediate initial attachment to tracheal tissue was tested in an intratracheal inoculation assay. Significantly fewer RB63 than wild-type bacteria were recovered from the tracheas at 24 h after intratracheal inoculation. These results demonstrate that fimbriae are involved in enhancing the ability of B. bronchiseptica to establish tracheal colonization and are essential for persistent colonization at this site. Interestingly, anti-Bordetella serum immunoglobulin M (IgM) levels were significantly lower in animals infected with RB63 than in animals infected with wild-type B. bronchiseptica at 10 days postinoculation. Even at 30 days postinoculation, RB63-infected animals had lower serum anti-Bordetella antibody titers in general. This disparity in antibody profiles suggests that fimbriae are also important for the induction of a humoral immune response.  (+info)

Local production and detection of (specific) IgE in nasal B-cells and plasma cells of allergic rhinitis patients. (39/1321)

Allergic diseases are characterized by allergic complaints in the shock organ and specific immunoglobulin (Ig)E in serum. Literature data indicate that the nasal mucosa itself could produce at least a large part of the specific IgE in allergic rhinitis patients. In order to investigate this hypothesis, nasal mucosal biopsies from the inferior turbinate were taken from symptomatic grass pollen allergic rhinitis patients, symptomatic house dust mite allergic rhinitis patients and nonallergic healthy controls, confirmed by radioallergosorbent test and skin-prick test. Immunohistochemical double-staining was performed for B-cells (CD19) with IgE, plasma cells (CD138) with IgE and plasma cells with biotinylated allergens. Significantly more IgE-positive B-cells and IgE-positive plasma cells were found in the nasal mucosa of allergic patients than in that of nonallergic controls. Double staining with biotinylated allergens and plasma cells showed allergen-positive plasma cells in the nasal mucosa of allergic patients and no allergen-positive plasma cells in the nasal mucosa of nonallergic patients. Blocking experiments using polyclonal antibodies directed against IgE showed a significant reduction in the number of allergen-positive cells in contrast to experiments using polyclonal antibodies directed against IgG, IgA or IgM. This study describes new evidence that specific immunoglobulin E is produced locally in the nasal mucosa in patients with seasonal allergic rhinitis and perennial allergic rhinitis, but not in nonallergic controls.  (+info)

Effects of nasal continuous positive airway pressure on awake ventilatory responses to hypoxia and hypercapnia in patients with obstructive sleep apnea. (40/1321)

This study was aimed to examine the short- and long-term effects of nasal continuous positive airway pressure (CPAP) on the chemosensitivity to hypoxia and hypercapnia in the patients with obstructive sleep apnea (OSA). Awake ventilatory responses to hypoxia and hypercapnia were examined in 28 patients (3 female) with moderate to severe OSA. All these tests were examined before and after 2 weeks of nasal CPAP. In 10 patients these tests were repeated after 3-6 months of nasal CPAP. All were also tested for spirometry and arterial blood gas analysis. Patients were middle-aged (48.9 +/- 9.9 years) and their mean apnea-hypopnea index was 58.3 +/- 20.4/hour. After 2 week of nasal CPAP, PaO2 significantly increased (77.7 +/- 11.8 vs. 84.6 +/- 9.8 mmHg) and PaCO2 significantly decreased (44.9 +/- 3.8 vs. 42.3 +/- 3.7 mmHg). The ventilatory response to hypoxia significantly decreased (0.80 +/- 0.51 vs. 0.61 +/- 0.51 liter/min/%) whereas the ventilatory response to hypercapnia significantly increased after 2 weeks (1.47 +/- 0.73 vs. 1.80 +/- 0.76 liter/min/mmHg). Similar findings were also observed after 3-6 months of nasal CPAP in 10 OSA patients. Nasal CPAP treatment can alter the ventilatory responses in patients with OSA.  (+info)