GABA-mediated component in the feedback response of turtle retinal cones.

The negative feedback from horizontal cells to cone photoreceptors contributes to the formation of the receptive-field surround in cone photoreceptors. Recently, studies on the modulation of voltage-gated Ca(2+) currents in cone photoreceptors have led to great progress in our understanding of the mechanism of horizontal-cone feedback. Another highly probable hypothesis is that GABA mediates this feedback. This hypothesis is supported by the facts that cone photoreceptors respond to GABA and that horizontal cells release GABA. However, GABA-mediated synaptic inputs from horizontal cells to cone photoreceptors have not been demonstrated. In the present study, we examined whether cone photoreceptors receive GABAergic inputs from horizontal cells using a slice patch technique in the turtle retina. When 1 mM of GABA was applied to the cone photoreceptors, GABA-induced currents were activated. GABA-induced currents reversed their polarity at the equilibrium potential of Cl-. The application of 30 microM of SR95531, an antagonist of GABAA receptors, alone did not produce any change in the holding currents. When 200 microM of pentobarbital was introduced to potentiate the GABAergic inputs to the cone photoreceptors, however, the inhibitory action of SR95531 on GABAergic inputs became detectable. The amplitude of the GABAergic inputs, potentiated by pentobarbital, increased when the horizontal cells were depolarized by the application of 20 microM of kainate, while the amplitude decreased when the horizontal cells were hyperpolarized by the application of 10 microM of CNQX. When the cone photoreceptors were voltage clamped at a potential at which the voltage-gated Ca(2+) current was inactive, horizontal-cone feedback was not observed. However, the horizontal-cone feedback became detectable when the GABAergic inputs to the cone photoreceptors were potentiated by pentobarbital. We concluded that the contribution of GABAergic inputs from horizontal cells to cone pedicles in the formation of the receptive-field surround in cone photoreceptors is very limited but that the modulation of voltage-gated Ca(2+) currents in cone photoreceptors is a physiologically relevant mechanism for horizontal-cone feedback.

[A case of idiopathic interstitial pneumonia with marked increase of CA19-9 in serum and BALF].

A 84-year-old man was admitted with dyspnea. Chest X-ray and CT showed honeycombing in the dorso-basal segments of the lung bilaterally. Idiopathic interstitial pneumonia (IIP: chronic, typical type) was diagnosed in accordance with the clinical criteria proposed by the Japanese Ministry of Health and Welfare. An extensive examination revealed no malignancy. However, the CA 19-9 level in bronchoalveolar lavage fluid (BALF) was very high (5,700 U/ml). An immunohistochemical test of lung tissue obtained by transbronchial lung biopsy was positive for CA 19-9 in bronchiolar epithelial and goblet cells. This case suggests that CA 19-9 is occasionally produced on a large scale in the lung of patients with IIP.

Electroretinographic changes in eyes with idiopathic macular hole treated by vitrectomy.

We recorded full-field electroretinograms before and after vitrectomy in 18 eyes of 18 patients with idiopathic macular hole. The results were compared between affected and fellow eyes in the preoperative and early (within 10 days) and late (3 to 6 months) postoperative periods. No significant changes between affected and control eyes were found in the amplitude of the rod electroretinogram, mixed cone-rod electroretinogram, cone electroretinogram a- and b-waves or 30-Hz flicker electroretinogram in all stages of the study. The peak implicit times of the cone electroretinogram (a- and b-wave) and dark- and light- adapted oscillatory potential (O1-O4), however, were delayed. Also, the amplitude of the oscillatory potentials (O1+O2+O3+O4) was significantly reduced in the early postoperative period. By the late period, all of these changes had resolved. We concluded that electrophysiologic changes were derived from a transitory dysfunction of the inner retina. The possible causes of the electroretinographic changes would include mechanical trauma of the surgery, intravitreous air tamponade or the changes in vitreous electrolytes after surgery. Oscillatory potentials were more sensitive than a- and b-waves in eliciting dysfunction of the inner retina in operate on eyes.

[Proliferating cell nuclear antigen (PCNA) immunolocalization in human nasal epithelium with chronic sinusitis detected by confocal laser scanning microscopy].

This study examines the immunohistological localization of proliferating cell nuclear antigen in the nasal and paranasal sinus epithelium from a group of patients undergoing sinus surgery for chronic sinusitis. PCNA immunoreactivity as determined by fluorescence intensity and the density of labeled cells as assessed by confocal laser scanning microscopy. The control group consisted of seven specimens taken from patients with post operative maxillary cyst and optic nerve canal fracture. In this group, most of the labeled cells were located on the basal cell layers with a few on the intermediate cell layers. The average labeled cell densities were 57.3 cells/mm2 on the basal cell layers and 15.9 cells/mm2 on the intermediate cell layer. The sinusitis group consisted of eleven patients. In contrast with the control group, the sinusitis epithelium displayed a significantly high proportion of goblet and intermediate cells positively stained for PCNA. The average densities were 84.9 cells/mm2 on the basal cell layers and 133.1 cells/mm2 on the intermediate cell layers in this group, the latter being nearly ten fold greater than that in the control group. Epithelial PCNA expression was correlated with the degree of inflammatory cell infiltration assessed by serial sections for each sample. A positive correlation was observed between these two factors (R = 0.63, Pearson). We believe that epithelial cell turnover is accelerated in chronic rhinosinusitis due to continuous exposure to various pathogens and host immune interventions. In those cases, goblet and intermediate cells would play the major role in enhanced epithelial proliferation.

A case of vascular leiomyoma of the larynx.

We present a 68-year-old woman with a vascular leiomyoma of the larynx, a benign tumour that rarely involves that organ. Chief complaints were a feeling of a narrowing of the pharynx and difficulty in breathing in the supine position. A spherical tumour measuring 1.5 cm and covered with normal mucosa was found at the margin of her epiglottis. The patient was administered a general anaesthetic and the tumour was successfully removed via direct laryngoscopy. Histological examination revealed that the tumour lay beneath a layer of stratified squamous epithelium and was encased in a well-defined fibrous capsule. The tumour parenchyma was composed of proliferated fibres that consisted of elongated cells, surrounded by an abundance of blood vessels. Its complete removal is the treatment of choice with care taken to avoid profuse bleeding. Recurrence is rare.

[A case of adult Chlamydia pneumoniae pneumonia diagnosed from a culture method].

We diagnosed a 41-year-old female patient to be suffering from Chlamydia pneumoniae (C. pneumoniae) by using PCR and culture methods. She had a prolonged dry cough and slight fever. Her chest roentgenogram showed a segmental infiltration in the middle of the right lung field. We treated her with 400 mg of cefpodoxime proxetil (CPDX-PR) per day. On the 4th day after beginning the treatment with CPDX-PR, she still complained of a productive cough. We changed the treatment by using 300 mg of roxithromycin per day and these symptoms disappeared. To diagnose C. pneumoniae early, PCR, MIF and culture methods are very useful diagnostic tools.

[Tissue culture of guinea pig middle ear epithelium--morphological characterization and proliferative activities of cultured cells on fibroblast-reorganized collagen gels].

Long-term culture of the middle ear epithelium of guinea pigs was carried out on reconstituted floating collagen matrix. Fibroblasts established from the abdominal skin dermis of allogenic animals were used to reorganize hydrated collagen gels into a dermal-like matrix. The explants placed on the surface of these matrices were composed of pseudostratified columnar cells with polygonal flat outgrowth sheets, which could be maintained for up to one month. In contrast, with simple hydrated collagen gel, no lysis of the substrate was observed regarding this reorganized collagen gel. In order to examine the growth pattern of these culture cells, 5-bromodeoxyuridine (BrdU) was added to the medium during the entire culture period. The specimens were immunohistologically stained using monoclonal antibodies. Noticeable changes were observed in the marginal portion of the explant where the cell shape changed from cuboidal to squamous. In this transitional area, most cells showed positive staining and consequently high proliferative activity. In the central area of the explants, however, the number of positive cells decreased and the main observation was a few labeled basal cell nuclei. It was suggested that the same regenerative process which usually occurs in normal respiratory epithelia after mechanical injury or other insults, was replayed in this culture system.