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Biomedical subjects

Y Naya

Publications and source records attributed to Y Naya.

47 records · Page 3Linked to original sources
PubMed1990

[Clinical study of imipenem/cilastatin sodium in children with severe infections].

Clinical studies of imipenem/cilastatin sodium (IPM/CS) were conducted in 40 pediatric patients. 29 out of the 40 patients were treated for infections and 11 for prophylaxis. The following results were obtained. 1. The response rate in 29 patients with infections was 79.3%. Among the 29 patients, 16 patients who presented with malignant diseases showed the response rate of 68.8%. The response rate was lower in patients with severe infections than in those with mild or moderate infections, and a lower response rate was associated with severe neutropenia. However, there were no differences in the response rates between patients who had previously been treated and those who had been untreated with other antibiotics. The response rate in 6 patients from whom causative organisms were isolated was 83.3% and that in the remaining 23 patients was 78.3%. 2. The response rate in 11 patients to whom IPM/CS was administered prophylactically was 63.6%. 3. As for side effects, a rash was observed in 1 patient and hematuria in another, and the abnormal laboratory test results observed were elevations of GOT and GPT in 1 patient. However, they were not clinically significant. From the above results, it appears that IPM/CS may be used as a drug of the first choice for the treatment of patients with severe infections in which the causative organisms are unknown, and for the prophylaxis of infection in patients with neutropenia.

Bacterial Infections↗
PubMed1989

What is molt-inhibiting hormone? The role of an ecdysteroidogenesis inhibitor in the crustacean molting cycle.

The in vivo molt-inhibitory effects of the ecdysone biosynthesis inhibitors 3-hydroxy-L-kynurenine and xanthurenic acid were investigated. These ecdysone biosynthesis inhibitors, isolated from the eyestalks of blue crabs (Callinectes sapidus), were injected into eyestalk-ablated crayfish (Procambarus clarkii). The active factor was found to be species-nonspecific within crabs and crayfish. The seasonal profiles of the xanthurenic acid and ecdysone titers exhibited a staggered relationship. Moreover, the activity of a 3-hydroxy-L-kynurenine aminotransferase varied during the molting cycle. The data suggested that 3-hydroxy-L-kynurenine, which is secreted from the X-organ-sinus gland complex of crustaceans, is released into the hemolymph, and after accumulating at the surface of the Y-organ, is converted into the active form, xanthurenic acid. Xanthurenic acid was found to profoundly repress ecdysteroidogenesis in vitro.

Journal Article↗
PubMed1988

Endogenous inhibitor of ecdysone synthesis in crabs.

Attempts to isolate the molt-inhibiting hormone (MIH) of crustaceans from crab eyestalks (ES) resulted in the characterization of xanthurenic acid as an inhibitor of ecdysone biosynthesis in the cultured Y-organ-complex (YOC) homogenate. It was also found that 3-hydroxy-L-kynurenine present in the ES is transformed into xanthurenic acid in the YOC and body fluid. Its mode of inhibitory action in ecdysone biosynthesis is probably inactivation of cytochrome P-450.

Animals↗
PubMedDate not supplied

Backward signal from medial temporal lobe in neural circuit reorganization of primate inferotemporal cortex.

Neuropsychological theories proposed a critical role of the interaction between the medial temporal lobe and neocortex in the formation of long-term memory for facts and events, which has often been tested by learning of a series of paired words or figures in humans. We identify neural mechanisms of this long-term memory formation process by single-unit recording and molecular biological methods in an animal model of visual pair-association task in monkeys. In our previous studies, we found a group of neurons that manifested selective responses to both of the paired associates (pair-coding neuron) in the anterior inferior temporal (IT) cortex. It provides strong evidence that single IT neurons acquire the response-selectivity through associative learning, and suggests that the reorganized neural circuits for the pair-coding neurons serve as the memory engram of the pair-association learning. In this article, we investigated further mechanisms of the neural circuit reorganization. First, we tested the role of the backward connections from the medial temporal lobe to IT cortex. Ibotenic acid was injected unilaterally into the entorhinal and perirhinal cortex which provided massive backward projections ipsilaterally to IT cortex. We found that the limbic lesion disrupted the associative code of the IT neurons between the paired associates, without impairing the visual response to each stimulus. Second, we ask why the limbic-neocortical interactions are so important. We hypothesize that limbic neurons would undergo rapid modification of synaptic connectivity and provide backward signals that guide reorganization of neocortical neural circuits. We then investigated the molecular basis of such rapid synaptic modifiability by detecting the expression of immediate-early genes. We found strong expression of zif268 during the learning of a new set of paired associates, most intensively in area 36 of the perirhinal cortex. All these results with visual pair-association task support our hypothesis, and demonstrate that the 'consolidation' process, which was first proposed on the basis of clinico-psychological evidence, can now be examined in the primate with neurophysiolocical and molecular biological approaches.

Animals↗
PubMedDate not supplied

Efficacy of sildenafil as the first-step therapeutic tool for Japanese patients with erectile dysfunction.

The aim of this study was to assess the efficacy of sildenafil as the first-step tool for erectile dysfunction (ED) in Japanese males. Between March 1999 and March 2003, 281 patients were prescribed five tablets of sildenafil (50 mg) as the first step in the therapeutic management of ED. Of the 281 patients, 206 were evaluable patients. The overall success rate in achieving sexual intercourse in subjects after taking sildenafil was 77.2% (159/206), while 22.8% (47/206) were unsuccessful. The success rates in men with functional ED and organic ED were 91.4% (85/93) and 65.5% (74/113), respectively (P<0.0001). Overall, transient adverse effects of sildenafil occurred in 16 (8%) males. Intolerable adverse effects (edema and dizziness) occurred in only 1% of patients (2/206). Sildenafil citrate may be recommended as the first choice drug for ED because of its high success rate and low invasiveness.

Adult↗
PubMedDate not supplied

Efficacy of sildenafil for Japanese patients with audio-visual sexual stimulation (AVSS) test by the RigiScan Plus.

Sildenafil is most effective in men with mild-to-moderate ED, but not severe ED in Japan. In order to evaluate the efficacy of sildenafil, we conducted the present study using the AVSS test by the RigiScan Plus. The subjects were 56 patients (age: 34-82 years, mean: 60.5 years) with ED. The IIEF5 questionnaire and the AVSS test were conducted before and after administration of sildenafil. The penile rigidity could not be measured in 19 patients. Of these 19, sildenafil was effective in 7 and not effective in 12. The 7 cases in whom sildenafil was effective were all false-negatives. The sensitivity of sildenafil was 84%, and its specificity was 100%. This study suggests that the AVSS test by RigiScan Plus can objectively evaluate the efficacy of sildenafil, and shows potential for predicting that efficacy.

Adult↗
PubMedDate not supplied

Neuronal tuning and associative mechanisms in form representation.

We examine the hypothesis that the form representation in the anterior inferotemporal (AIT) cortex is acquired through learning. According to this hypothesis, perceptual aspects of the temporal association area are closely related to its visual representation, in that the response selectivity of AIT neurons can be influenced by visual experience. On the basis of the neurophysiological evidence, we summarize two neuronal mechanisms that subserve the acquisition of form selectivity in AIT neurons. The first mechanism is neuronal tuning to particular stimuli that were learned in a cognitive task. The second mechanism is association, with which relevant information can be retrieved from other stored memories. On the grounds that long-term memory of objects is acquired and organized by at least these two neuronal mechanisms in the temporal association area, we further present a model of the cognitive memory system that unifies perception and imagery.

Animals↗
PubMedDate not supplied

Lead contact lens for crystalline lens shielding in electron therapy for eyelid tumors.

In radiotherapy for eyelid tumors, a sufficient dose is required in the target tissue while preserving the crystalline lens. A I-mm thick, 20-mm diameter lead contact lens was prepared for crystalline lens protection. The lens was coated with an acrylic polymer and weighted 5.5 g. Six MeV electron therapy was scheduled using a 10 mm bolus on the eyelid. A simulation experiment proved that 0.78 +/- 0.04 percent of the maximal eyelid dose was given at the crystalline lens portion. A total of 14 eyelids in eight patients with cutaneous lymphoma, angiosarcoma, or basal cell carcinoma were treated with the contact lens. No cataract was found after irradiation over an average period of 24.3 months. The combination of the lead contact lens, bolus, and 6 MeV electron beam was a simple procedure and provided adequate dose distribution in the treatment of various eyelid tumors.

Aged↗