65 research outputs found

    Activity patterns of cochlear ganglion neurones in the starling

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    1. Spontaneous activity and responses to simple tonal stimuli were studied in cochlear ganglion neurones of the starling. 2. Both regular and irregular spontaneous activity were recorded (Figs. I to 5). Non-auditory cells have their origin in the macula lagenae. Mean spontaneous rate for auditory cells (all irregularly spiking) was 45 spikes s-1. 3. In half the units having characteristic frequencies (CFs) <1.5 kHz, time-interval histograms (TIHs) of spontaneous activity showed regularly-spaced peaks or 'preferred' intervals. The spacing of the peak intervals was, on average, 15% greater than the CF-period interval of the respective units (Fig. 11). 4. In TIH of lower-frequency cells without preferred intervals, the modal interval was also on average about 15% longer than the CF-period interval (Fig. 11). Apparently, the resting oscillation frequency of these cells lies below their CF. 5. Tuning curves (TCs) of neurones to short tone bursts show no systematic asymmetry as in mammals. Below CF 1 kHz, the low-frequency flanks of the TCs are, on average, steeper than the high-frequency flanks. Above CF 1 kHz, the reverse is true (Fig. 15). 6. The cochlear ganglion and nerve are tonotopically organized. Low-frequency fibres arise apically in the papilla basilaris and are found near non-auditory (lagenar) fibres (Figs. 2 and 19). 7. Discharge rates to short tones were monotonically related to sound presure level (Fig. 20). Saturation rates often exceeded 300 spikes s- 1. 8. 'On-off' responses and primary suppression of spontaneous activity were observed (Figs. 22 and 23). 9. A direct comparison of spontaneous activity and tuning-curve symmetry (Fig. 15b) revealed that, apart from quantative differences, fundamental qualitative differences exist between starling and guinea-pig primary afferents

    Pathogens in COPD exacerbations identified by comprehensive real-time PCR plus older methods

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    Kenichiro Shimizu,1 Yutaka Yoshii,1 Miyuki Morozumi,2 Naoko Chiba,2 Kimiko Ubukata,2 Hironori Uruga,3 Shigeo Hanada,3 Nayuta Saito,1 Tsukasa Kadota,1 Saburo Ito,1 Hiroshi Wakui,1 Naoki Takasaka,1 Shunsuke Minagawa,1 Jun Kojima,1 Hiromichi Hara,1 Takanori Numata,1 Makoto Kawaishi,1 Keisuke Saito,4 Jun Araya,1 Yumi Kaneko,1 Katsutoshi Nakayama,1 Kazuma Kishi,3 Kazuyoshi Kuwano1 1Division of Respiratory Diseases, Department of Internal Medicine, The&nbsp;Jikei University School of Medicine, 2Department of Infectious Diseases, Keio University School of Medicine, 3Department of Respiratory&nbsp;Medicine, Respiratory Center, Toranomon Hospital, 4Department of Respiratory Medicine, The Jikei University Daisan Hospital, Tokyo,&nbsp;Japan Abstract: Respiratory infection is a major cause of exacerbation in chronic obstructive pulmonary disease (COPD). Infectious contributions to exacerbations remain incompletely described. We therefore analyzed respiratory tract samples by comprehensive real-time polymerase chain reaction (PCR) in combination with conventional methods. We evaluated multiple risk factors for prolonged hospitalization to manage COPD exacerbations, including infectious agents. Over 19 months, we prospectively studied 46 patients with 50 COPD exacerbations, collecting nasopharyngeal swab and sputum samples from each. We carried out real-time PCR designed to detect six bacterial species and eleven viruses, together with conventional procedures, including sputum culture. Infectious etiologies of COPD exacerbations were identified in 44 of 50 exacerbations (88%). Infections were viral in 17 of 50 exacerbations (34%). COPD exacerbations caused by Gram-negative bacilli, including enteric and nonfermenting organisms, were significantly associated with prolonged hospitalization for COPD exacerbations. Our results support the use of a combination of real-time PCR and conventional methods for determining both infectious etiologies and risk of extended hospitalization. Keywords: COPD, exacerbation, etiology, real-time PCR, prolonged hospitalization, risk facto
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