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Biomedical subjects

S Oono

Publications and source records attributed to S Oono.

At least 19 recordsLinked to original sources
PubMed1995

Hyperosmolality rapidly reduces atrial-natriuretic-peptide-dependent cyclic guanosine monophosphate production in cultured rat inner medullary collecting duct cells.

The present study was undertaken to explore the acute effect of hyperosmolality on the response of cultured rat inner medullary collecting duct (IMCD) cells to atrial natriuretic peptide (ANP). In contrast to the stimulatory effect of chronic incubation (12 h) in hypertonic medium, it was found that short-term incubation (< 2 h) reversibly suppressed the ANP-dependent cyclic guanosine monophosphate (cGMP) production. Urea, NaCl and mannitol were equi-potent as the osmolyte in suppressing the ANP-dependent cGMP production. Receptor binding assay revealed that hyperosmolality induced a rapid and marked reduction of the maximum binding (Bmax) of ANP without a significant change of the dissociation constant (Kd). Pretreatment with protein kinase C inhibitors (calphostin-C, staurosporin) or with cytoskeleton modulators (cytochalasin-B, colchicine) did not affect the inhibitory effect of hyperosmolality. In conclusion, acute hypertonicity inhibited the ANP-induced cGMP production in contrast to chronic hypertonicity, and reduction of the number of ANP binding sites was considered to be a mechanism responsible for the inhibitory effect of hypertonicity.

Alkaloids↗
PubMed1995

[Incidence of acute idiopathic optic neuritis and its therapy in Japan. Optic Neuritis Treatment Trial Multicenter Cooperative Research Group (ONMRG)].

Data on the incidence of and treatment for acute idiopathic optic neuritis were obtained by questionnaire sent to departments of ophthalmology, university hospitals, and general hospitals throughout Japan. Inquiry was made as to the number of cases which developed idiopathic optic neuritis from April 1992 to March 1993 along with their clinical features. The response rate was 53.6%. There were a total of 550 cases, and the male to female ratio was 1:1.22. Patients 14 to 55 years old were 65.9%; bilateral involvement: 28.2%; recurrence: 18.6%; positive past history of the other eye; 7.5%. Assuming the answering rate to be 100% and two thirds of the patients to be included, annual incidence of this disease (the annual number of patients) was determined to be 1.62 for an adult population of 100,000 (1.03 cases/100,000 people). Tochigi, Tokyo, Kanagawa, Hyogo, Wakayama, Okayama, Yamaguchi, Tottori, Shimane, Ehime, and Fukuoka showed an annual incidence exceeding 2.0/100,000 adults. At more than 95% of all medical institutions questioned, patients with optic neuritis were usually treated with systemic corticosteroids. Oral corticosteroid therapy, which was shown in a recent study in USA to be contraindicated, was still being used at 15% of the institutions.

Acute Disease↗
PubMed1994

Influence of simultaneous pattern-reversal electroretinogram recording on visual evoked potentials.

Little is known about the influence of the presence of a gold-foil electrode on pattern-reversal visual evoked potential recording, although simultaneous pattern-reversal electroretinography has been applied in several clinical investigations. We compared the results of pattern-reversal visual evoked potentials simultaneously recorded with pattern-reversal electroretinograms with those obtained during separate pattern-reversal visual evoked potential recording in 10 normal subjects. Transient response (reversal rate, 1 Hz; check size, 30') and steady-state response (reversal rate, 5 Hz; check size, 120', 60', 30', 15' and 7.5') were analyzed under the stimulus contrast condition of 90%. Neither P100 latency in transient responses nor amplitudes in steady-state responses exhibited significant change at any check size when they were recorded separately or simultaneously with pattern-reversal electroretinograms. The results suggest that the gold-foil electrode exerts no significant influence on pattern-reversal visual evoked potentials. Simultaneous pattern-reversal electroretinogram and visual evoked potential recording is therefore confirmed to be a clinically useful method. This procedure makes the synchronous recording of both responses possible under the identical stimulus conditions.

Adult↗
PubMed1994

[Heterogeneity in gastric carcinoma with special reference to DNA content and mitotic activity: histopathologic differentiation].

DNA ploidy was microspectrophotometrically investigated in 46 patients with gastric carcinoma. Measurements of DNA content and mitotic index (MI) were examined in the mucosal, submucosal, muscularis propria, and serosal layers of tumors, respectively. The frequency of cells with values exceeding hexaploid chromosome (6c) and mitotic counting analysis revealed a significantly higher value in the serosa than in the mucosa. This tendency was not evident in differentiated type adenocarcinoma but was noted in those with the undifferentiated type. There were 37 tumors (80.0%) with the same DNA distribution pattern in every layer of the stomach (homogeneous DNA ploidy). Heterogeneity of DNA ploidy was observed in nine tumors (20.0%). Carcinoma with heterogeneous DNA ploidy manifested a significantly higher incidence of metastasis to lymph nodes than did those with the homogeneous type. Characteristically, there was venous permeation preponderance in the differentiated type and peritoneal dissemination preponderance in the undifferentiated type. This evidence of DNA heterogeneity in gastric carcinoma tissue suggests a possible correlation with metastatic behavior.

Adenocarcinoma↗
PubMed1993

Pattern-reversal visual evoked potentials in Down's syndrome.

We examined pattern-reversal visual evoked potentials (PRVEPs) in 36 adult patients with Down's syndrome, and analyzed the effects of the ophthalmological abnormalities on results of PRVEPs. The P100 latency was significantly delayed in 24 eyes of 16 patients. The P100 latency was significantly longer and its amplitude was significantly smaller (P < 0.001) in Down's syndrome patients than in age-matched normal controls. In 9 patients without any ophthalmological abnormalities, P100 latency showed no significant difference from that in normal controls, but three of them showed a significant delay of P100. Their P100 amplitudes were significantly smaller than those in normal controls. Therefore, we considered that the ophthalmological abnormalities are one of the main factors causing PRVEPs abnormalities in Down's syndrome patients, but some unknown factors should be also responsible.

Adult↗
PubMed1993

Reconstruction of cornea in three-dimensional collagen gel matrix culture.

PURPOSE: To report on an in vitro reconstruction of cornea composed of three main layers. METHODS: These layers were reconstructed from isolated bovine corneal cells in three-dimensional collagen gel culture conditions. RESULTS: The topmost layer, corneal epithelial cells on collagen gel, was treated by what was designated as the "air-liquid interface method," a method developed specifically for this study. The treatment induced proliferation and differentiation of this layer. Those epithelial cells were positively immunostained with anti-epithelial keratin (55-kD/64-kD) antibody, AE5, which was specific for in vivo corneal epithelial cells. The middle layer consisted of keratocytes in the three-dimensional collagen gel matrix. This layer was comparable to the stroma in vivo. The underlayer, the counterpart of in vivo endothelial layer, was composed of corneal endothelial cells. CONCLUSIONS: This culture system probably provides a physiologic environment for detailed investigations of corneal cells.

Animals↗
PubMed1993

Distribution of the innervating neurons of pupillary dilator and tarsal muscles in the superior cervical ganglion.

In an experimental study using adult cats, we analyzed the distribution of the sympathetic postganglionic neurons in the superior cervical ganglion (SCG) which innervate the pupillary dilator and tarsal muscles to determine whether there are direct fiber projections from the spinal cord to the iridic and tarsal muscles. This study consisted of three experiments. In Experiments 1 and 2, respectively, horseradish peroxidase (HRP) was injected unilaterally into the iridic stroma or superior tarsal muscles. The SCG and spinal cord were then removed for microscopic analysis. In Experiment 3, the ganglion was examined microscopically after the injection of bisbezimide into the iris and of HRP into the ipsilateral superior tarsal muscle. Experiment 1 revealed more numerous HRP-labeled neurons in the rostral part than in any other region of the ipsilateral superior cervical ganglion. In Experiment 2, HRP-labeled neurons were evenly distributed over the whole ipsilateral SCG. No HRP-labeled neurons were detected in the spinal cord in either of these experiments. In Experiment 3, no doubly-labeled neurons were discernible in the ganglion. These results clearly indicate the localization of internal carotid nerve cells in a specific region of the SCG, and provide evidence for the absence of postganglionic neurons that innervate both the dilator muscle of the pupil and the tarsal muscles.

Adrenergic Fibers↗
PubMed1992

The pharmacokinetics of fluconazole during haemodialysis in uraemic patients.

We have studied the pharmacokinetics of fluconazole in five patients on long-term haemodialysis. The single-pass extraction rate of the dialyzer was 59 (3.5)% (n = 4), and the serum concentration was reduced by haemodialysis for 3 or 4 h by 26 (3.2)% (n = 5) and 39 (2.2)% (n = 9) respectively. The estimated amount extracted by a dialysis of 4 h was 33 (3.2)% (n = 4) of the dose. During repeated administration the serum fluconazole concentration increased, reaching a plateau at about 4 times the peak concentration after the first dose. After discontinuing administration the serum fluconazole concentration fell by 25% in every 3 h dialysis session. We conclude that fluconazole should be given in the usual dose of 100 or 200 mg at the end of every haemodialysis session.

Aged↗
PubMed1982

A solid-state television pupillometer.

An application of an MOS-type solid-state imaging sensor to a television pupillometer is described. Its advantages over the conventional image-tube pupillometers using silicon vidicons are demonstrated with special emphasis on its excellent dynamics performance. Design considerations for an MOS-type solid-state TV camera and the schematic diagram of a pupillometer which detects the horizontal pupillary diameter are presented. Two methods of infrared illumination giving no heat sensation to subjects are also proposed: the effective use of an aquatic filter and solid-state illumination utilizing i.r.-LEDs.

Humans↗