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T Nagano

Publications and source records attributed to T Nagano.

At least 181 records · Page 10Linked to original sources
PubMed1995

Self-organization of the velocity selectivity of a directionally selective neural network.

We first present a mathematical analysis of the relation between the parameters and the behavior of the basic module in the proposed neural network model for visual motion detection. Based on the analytical results, a learning rule is put forth that can develop velocity selectivity of directionally selective cells in the basic module. The learning rule is furthermore introduced into the total model called a 'mass model', which is constructed with many basic modules. Numerical simulation results showed that each basic module in the mass model learned in a self-organizing manner to acquire selectivity for the velocity of an input stimulus. The proposed learning rule would be plausible in the actual nervous system in that it is simple and can be described with only local information.

Animals↗
PubMed1995

Endothelium-derived relaxing factors in the kidney of spontaneously hypertensive rats.

Acetylcholine (ACh)-induced vasodilation is mainly due to endothelium-derived nitric oxide (EDNO) and hyperpolarizing factor (EDHF). To explore the mechanisms underlying attenuated endothelium-dependent vasodilation in hypertensive arteries, we measured the EDNO released from isolated kidneys of spontaneously hypertensive rats (SHR) using a sensitive chemiluminescence assay system of NO. ACh-induced renal vasodilation was significantly smaller in SHR than in the normotensive control, Wistar-Kyoto rats (WKY). However, ACh-induced NO release did not differ between SHR and WKY (10(-7) M: SHR +37 +/- 2 [SE] vs. WKY +32 +/- 4 fmol/min/g kidney). Perfusion with a 20 mEq/L high-K+ buffer, which is reported to inhibit action of EDHF, significantly reduced ACh-induced vasorelaxation in WKY but not in SHR, resulting in identical renal perfusion pressure in SHR and wKY under these conditions. These results indicate that attenuated ACh-induced vasorelaxation in the SHR kidney may be attributed to a decrease in EDHF rather than that in EDNO.

Acetylcholine↗
PubMed1995

Regional distribution of messenger RNA encoding the insulin-like growth factor type 2 receptor in the rat lower brainstem.

Distribution of messenger RNA (mRNA) encoding the insulin-like growth factor (IGF) type 2 receptor (IGF2R) is investigated in the rat lower brainstem by in situ hybridization histochemistry. Cells with IGF2R mRNA are distributed widely in a region-specific manner. It is expressed in: (1) motor nuclei such as the oculomotor nucleus, trochlear nucleus, motor trigeminal nucleus, abducens nucleus, facial nucleus, ambiguus nucleus, dorsal motor nucleus of vagus and hypoglossal nucleus; (2) several sensory-related nuclei like the mesencephalic trigeminal nucleus, ventral nucleus of the lateral lemniscus, lateral and spinal vestibular nuclei, ventral and dorsal cochlear nuclei and nucleus of the trapezoid body; and (3) other regions such as the red nucleus, dorsal raphe nucleus, pontine nuclei, three cerebellar nuclei (medial, interposed and lateral), Purkinje cells, cells in the granular layer of the cerebellum, locus coeruleus, several areas of the reticular nucleus and area postrema.

Animals↗
PubMed1995

Screening and determination of methamphetamine and amphetamine in the blood, urine and stomach contents in emergency medical care and autopsy cases.

Methamphetamine (MA) and amphetamine (AMP) were screened and their levels were determined using the Toxi-Lab thin-layer chromatography system and gas chromatography-mass spectrometry, respectively, in the blood, urine and stomach contents from 211 emergency medical care and 417 autopsy cases. MA and AMP were detected in 5 emergency medical cases, and the blood MA and AMP concentrations ranged from 0.697-0.041 micromol/100 g and from 0.0944-0.0003 micromol/100 g, respectively. MA and AMP were detected in 19 autopsy cases, in which blood MA and AMP concentration ranged from 14.3-0.123 micromol/100 g and from 0.256-0.0017 micromol/100 g, respectively. The autopsy cases included 5 cases of sudden death with blood MA concentration of less than 3 micromol/100 g. MA and AMP screening and determination in emergency medical care and autopsy cases provide useful information and are indispenable in clarifying the dimensions of MA abuse in Japan.

Journal Article↗
PubMed1995

Screening of volatile substances and determination of toluene (a thinner component) in the blood and urine in emergency medical care and autopsy cases by the pulse heating method.

Screening of volatile substances was performed by pulse heating gas chromatography - mass spectrometry (GC-MS) using a GS-Q column in 211 emergency medical care and 342 autopsy cases. At least 36 standard substances could be separately detected. Six kinds of volatile substances were screened in a total of 553 cases. Toluene and/or hippuric acid were detected in the blood and/or urine in respectively, 4 emergency medical care and 8 autopsy cases. There were 11 abusers (9 males and 2 females) in these 12 positive cases. The ages of the abusers ranged from 13-26 years. There was no particular pattern to the monthly frequency distribution of identification of thinner (toluene) abuse cases, which occurred throughout the year. It is believed that these data at least partly reflect the present status of thinner/glue abuse in Japan. We conclude that pulse heating GC-MS is useful in the screening and quantitative determination of volatile substances including toluene and other thinner/glue components.

Journal Article↗
PubMed1995

Different effects of absorption promoters on corneal and conjunctival penetration of ophthalmic beta-blockers.

PURPOSE: The purpose of this study was to investigate the improvement in corneal penetration of ophthalmic beta-blockers of various lipophilicities afforded by absorption promoters and to compare the corneal against conjunctival penetration in response to absorption promoters. METHODS: The penetration of the beta-blockers, atenolol, carteolol, tilisolol, timolol, and befunolol, in the presence of absorption promoters, across the isolated corneal and conjunctival membranes of albino rabbits was measured using a two-chamber glass diffusion cell. EDTA, taurocholic acid, capric acid, and saponin were used as the absorption promoters. RESULTS: The absorption promoters significantly increased the corneal permeability of most beta-blockers, especially the hydrophilic agents. The absorption promoters also enhanced the conjunctival permeability of beta-blockers, although their effect in promoting conjunctival penetration was less than that on corneal penetration. There was a differing penetration of instilled beta-blockers in the cornea and conjunctiva in response to absorption promoters. Capric acid and saponin showed significant promoting action on corneal penetration, but not on conjunctival penetration. Taurocholic acid had a significant effect on conjunctival penetration but not on corneal penetration. Saponin caused slight irritation. CONCLUSIONS: Absorption promoters can improve the ocular delivery of beta-blockers and a selective use of absorption promoter can improve the extent and pathway of drug ocular absorption.

Absorption↗
PubMed1995

Establishment of a rabbit short-term dry eye model.

The dry eye syndrome is a chronic disease which can become a serious threat to useful vision. However, there is only a limited understanding regarding effective treatment or prevention of this disease. Establishing an effective mode of treatment requires the use of a satisfactory animal dry eye model. Ideally, such a model should rapidly determine the effectiveness of agents that inhibit the damaging effects of this syndrome. This paper presents a short-term dry eye model using rabbits, which combines mechanical prevention of blinking and methylene blue staining. This model is not intended to be a precise representation of the dry eye syndrome, since this disorder has recently become recognized to involve a primary pathological process of the corneal and conjunctival epithelium. However, by using this model, clinical signs of dry eye can be observed after a few hours in the form of acute desiccation. Corneal damage can easily be evaluated both qualitatively by methylene blue staining scores, and quantitatively by chronic assay. Visually observed corneal epithelial thinning was confirmed by scanning electron microscopy (SEM) to be due to loss of epithelial integrity. Using a 3% chondroitin sulfate solution, an already proven effective agent for dry eye, this model effectively demonstrated an 80% inhibition in the development of methylene blue positive lesion after a period of only 2 hours. This short term dry eye model is valuable in primarily screening the efficacy of potential therapeutic agents in the prevention and treatment of dry eye.

Animals↗
PubMed1995

Yersinia pseudotuberculosis in China.

Thirty strains of Yersinia pseudotuberculosis were isolated from rabbits (17 strains), wild rats (9 strains) and house rats (4 strains) in China between 1990 and 1993. The biochemical properties of these isolates were identical with those of Y. pseudotuberculosis and no special characteristics were found in these strains. Serologically, serogroups 4b and 5b were identical to isolates found in Japan, and a new serogroup 1c and unclassified strains have also been detected. The existence of virulence-associated properties were different among strains. The pYV plasmid was detected from 6 strains of 30 isolates. This report documents the presence of Y. pseudotuberculosis in China, providing important epidemiological information.

Animals↗
PubMed1995

Activated liver macrophages in human liver diseases.

Immunohistochemical analysis using monoclonal antibodies specific for cells of monocyte/macrophage lineage reveals that resident liver macrophages have a phenotype distinct from that of monocytes or activated liver macrophages. Liver macrophages consist of heterogeneous cell populations in maturation (matured 25F9-positive and immature 25F9-negative) but the ratio of two populations is constant in normal and diseased livers. The expression of CD14 is down-regulated in resident liver macrophages as compared to that in monocytes, while the expression of 25F9 is up-regulated. On the other hand, the expressions of CD14 and Fc gamma RI are up-regulated in activated liver macrophages in viral and autoimmune hepatitis. In vitro culture of monocytes in medium without cytokines induces the phenotype similar to that of resident liver macrophages. Addition of macrophage-colony stimulating factor or interferon-gamma into the culture medium induces the expression of Fc gamma RI, the phenotype of which resembles that of activated liver macrophages. These results suggest that liver macrophages consist of heterogeneous cell populations and that both phenotype and function are affected by the local milieu of cytokines.

Animals↗
PubMed1995

Cyclin D and retinoblastoma gene product expression in actinic keratosis and cutaneous squamous cell carcinoma in relation to p53 expression.

Abnormality of the molecules regulating the cell cycle has been shown to lead cells to transformation. Recently, overexpression of cyclin D protein, one of the G1 cyclins, and the abnormality of the retinoblastoma gene have been found in various human cancers. We analyzed the expression of cyclin D, retinoblastoma gene product (pRB) and p53 in actinic keratoses (AKs) and cutaneous squamous cell carcinomas (SCCs) by immunohistochemistry to elucidate the role of these molecules in keratinocyte carcinogenesis. In the normal epidermis, a few cyclin D positive cells were seen mainly at the basal layer. In 11 seborrheic keratoses, no overexpression of cyclin D was observed. Twelve of 26 AKs (46%) and 27 of 45 SCCs (60%) showed cyclin D overexpression. A few pRB positive cells were seen in the basal layer and in the suprabasal spinous layer of the normal epidermis. An abnormality of pRB, loss of expression, was seen in 2 of 26 AKs (8%) and 7 of 45 SCCs (16%). p53 protein was positive in 12 of 26 AKs (46%) and 24 of 45 SCCs (53%). Forty-five SCCs examined were divided into 22 ultraviolet (UV)-related SCCs and 23 UV-unrelated SCCs. Though UV-related SCCs showed a significantly higher incidence of p53 positivity, as previously reported by us, no significant difference in cyclin D overexpression and loss of the pRB expression was observed between UV-related and UV-unrelated SCCs. These results suggest that cyclin D overexpression is frequently involved in keratinocyte carcinogenesis and that this is an early event, as well as p53 abnormality. In addition, abnormality of the retinoblastoma gene is also related to epidermal cell carcinogenesis, though the frequency is relatively low.

Carcinoma, Squamous Cell↗
PubMed1995

Reduction of ultraviolet-induced skin cancer in mice by topical application of DNA excision repair enzymes.

Ultraviolet (UV) irradiation produces two major photoproducts, cyclobutane pyrimidine dimers (CPD) and (6-4) photoproducts. T4 endonuclease V (T4N5), which specifically repairs CPD, is encapsulated in liposomes. A previous study has shown that UV-induced carcinogenesis in mice was suppressed by the application of T4N5 liposomes. To confirm the suppressive effect, we applied T4N5 liposomes with repeated UVB exposure to hairless mice. At the end of the experiment, mice treated with T4N5 liposomes had 3.5 +/- 1.3 tumors per mouse, and control mice had 6.3 +/- 2.8 tumors per mouse. In addition, the incidence of tumors was reduced in T4N5 liposome-treated mice compared with controls. The pathological diagnosis of the tumors was not significantly different between two groups. Immunohistochemical analysis of p53 protein in UV-induced tumors showed that nearly half of the tumors in both groups were positive. When the biopsied normal-looking skin taken during the experiment was stained with p53 antibody, there was no significant difference of the timing of p53 protein expression between the control mice and T4N5 liposome-treated mice. These results confirmed that CPD plays a pivotal role in UV carcinogenesis, although the molecular mechanisms of the suppression by T4N5 liposomes should be further clarified.

Administration, Topical↗
PubMed1995

Ophthalmic preservatives as absorption promoters for ocular drug delivery.

The effects of ophthalmic preservatives on the drug permeability through isolated ocular membranes of albino rabbits were investigated using a two-chamber glass diffusion cell. Tilisolol and fluorescein isothiocyanate (FITC)-dextrans (average molecular weights 4400 and 9400 Da; FD-4 and FD-10, respectively) were used as model penetrants of ophthalmic beta-blockers and peptide drugs. Preservatives significantly enhanced the corneal penetration of not only tilisolol but also FITC-dextrans. Especially, benzalkonium chloride increased the corneal permeability of FD-4 and FD-10 by 28.8 and 37.1 times, respectively. These results indicate the usefulness of ophthalmic preservatives as absorption promoters for the ocular delivery of beta-blockers and hydrophilic macromolecules. Preservatives also enhanced the conjunctival permeability of tilisolol, FD-4 and FD-10. The promoting effect of preservatives on the conjunctival drug penetration was smaller than that on the corneal one. Preservative increased the ratio of corneal to conjunctival permeability of tilisolol, FD-4 and FD-10. The different responses of corneal and conjunctival drug penetrations to ophthalmic preservatives may be useful to control the extent and pathway for the ocular and systemic absorptions of instilled drugs.

Absorption↗
PubMed1995

[Tissue type plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI) in transplanted kidneys].

We have studied the involvement of fibrinolysis in acute rejection after kidney transplantation by analyzing changes in urinary levels of substances such as FDP, D-dimer, tissue plasminogen activator (t-PA) and plasminogen activator inhibitor (PAI). Fibrinolytic activity was found to be low (that is, PAI is dominant) during acute rejection, and it was elevated (that is, PA became dominant) as acute rejection subsided. It appears that the dominance of PA leads to an increase in the products of fibrinolysis and an elevation in the D-dimer/FDP ratio, resulting in disappearance of the acute rejection. Based on these findings, we thought it necessary to administer t-PA to kidney recipients so that PA becomes dominant earlier and the acute rejection can be reduced. It is necessary for us to directly study the phenomena within the kidneys. Therefore, we recently conducted a histochemical study of the distribution of t-PA, Urokinase type PA (u-PA) and PAI in transplanted kidneys. Transplanted kidney, which functioned well or showed signs of acute or chronic rejection, were biopsied. These renal samples as well as control samples (biopsied from normal nongrafted kidney) were examined as to distribution of t-PA, u-PA and PAI by the indirect enzyme complement method. In conclusion, t-PA, u-PA and PAI were detected in the glomeruli, arterioles, tubule and interstices of the control kidneys, well functioning grafts, acutely rejected grafts chronically rejected grafts. All samples showed intense chromatic responses in the arterioles and part of the tubules. On the whole, the chromatic response tended to be more intense in the acute rejection group than in the other group.

Fibrinolysis↗
PubMed1995

[Clinical study on cerebrovascular diseases after renal transplantation].

Between October 1975 and December 1994, 131 renal transplants were performed on our hospital. Eight of these patients had 9 cerebrovascular diseases, which were 2 cerebral hemorrhages, 5 cerebral infarctions, 2 subarachnoid hemorrhages. Five of the 8 patients whose graft functions were bad died. We studied the relationship of the incidence of these complications to some factors as follows; 1) blood pressure, 2) hypercholestemia, 3) duration of hemodialysis, and 4) graft function. The cerebrovascular diseases after renal transplantation were related to the hypertension after renal transplantation and no correlation with the other factors could be found. Therefore, we think that the control of the hypertension after renal transplantation is the most important for the cerebrovascular diseases and the patient's prognosis.

Adult↗
PubMed1995

[Essential thrombocythemia transformed to minimally differentiated acute myeloid leukemia].

A 64-year-old female diagnosed for essential thrombocythemia was treated with MCNU 50 mg four times in the course of the disease. Six months after the last administration, in May 1991, she was admitted because of decreasing thrombocyte count and appearance of blasts in the peripheral blood. On admission, laboratory findings were as follows: WBC 700/microliters with 5% of blasts, RBC 331 x 10(4)/microliters, and PLT 17.9 x 10(4)/microliters. Bone marrow aspiration revealed hypocellular marrow with 39% blasts. About 5% of the blasts were positive for myeloperoxidase by electron microscopy analysis. Leukemic cells were positive for CD 7, 13, 33 and 34, negative for other lymphoid lineage markers, and demonstrated no rearrangement of TCR-beta, gamma and IgH genes. Although she was treated with low-dose cytosine arabinoside, no response was observed. Subdural hematoma and sequential pneumonia developed and the patient died eight months after leukemic transformation. In conclusion, we think that the leukemic transformation might have been developed in the natural course of essential thrombocythemia in the present case. However, we cannot exclude the influence of MCNU.

Cell Transformation, Neoplastic↗
PubMed1995

[Clinical statistics of 67 cadaveric renal transplantation at the Department of Urology, Kinki University School of Medicine].

A statistic survey was made on the patients undergoing cadaveric renal transplantation between June, 1980 and December, 1993. The total number of patients was sixty-seven. The number of patients per year increased annually. The graft survival rate was 73.8% at 1 year and 63.1% at 5 years. Some transition was seen in immunosuppressive regimens using cyclosporin.

Adolescent↗
PubMed1994

Lineage determination of CD7+ CD5- CD2- and CD7+ CD5+ CD2- lymphoblasts: studies on phenotype, genotype, and gene expression of myeloperoxidase, CD3 epsilon, and CD3 delta.

The gene expression of myeloperoxidase (MPO), CD3 epsilon, and CD3 delta molecules, the gene rearrangement of T-cell receptor (TCR) delta, gamma, and beta and immunoglobulin heavy (IgH) chain, and the expression of cell-surface antigens were investigated in seven cases of CD7+ CD5- CD2- and four cases of CD7+ CD5+ CD2- acute lymphoblastic leukemia or lymphoblastic lymphoma (ALL/LBL) blasts, which were negative for cytochemical myeloperoxidase (cyMPO). More mature T-lineage blasts were also investigated in a comparative manner. In conclusion, the CD7+ CD5- CD2- blasts included four categories: undifferentiated blasts without lineage commitment, T-lineage blasts, T-/myeloid lineage blasts, and cyMPO-negative myeloblasts. The CD7+ CD5+ CD2- blasts included two categories; T-lineage and T-/myeloid lineage blasts. The 11 cases were of the germ-line gene (G) for TCR beta and IgH. Four cases were G for TCR delta and TCR gamma. The others were of the monoclonally rearranged gene (R) for TCR delta and G for TCR gamma or R for both TCR delta and TCR gamma. The expression or in vitro induction of CD13 and/or CD33 antigens correlated with the immaturity of these neoplastic T cells, since it was observed in all 11 CD7+ CD5- CD2- and CD7+ CD5+ CD2-, and some CD7+ CD5+ CD2+ (CD3- CD4- CD8-) cases, but not in CD3 +/- CD4+ CD8+ or CD3+ CD4+ CD8- cases. CD3 epsilon mRNA, but not CD3 delta mRNA, was detected in two CD7+ CD5- CD2- cases, while mRNA of neither of the two CD3 molecules was detected in the other tested CD7+ CD5- CD2- cases. In contrast, mRNA of both CD3 epsilon and CD3 delta were detected in all CD7+ CD5+ CD2- cases, indicating that CD7+ CD5- CD2- blasts at least belong to T-lineage. The blasts of two CD7+ CD5- CD2- cases with entire germ-line genes and without mRNA of the three molecules (MPO, CD3 epsilon, and CD3 delta) were regarded as being at an undifferentiated stage prior to their commitment to either T- or myeloid-lineage. The co-expression of the genes of MPO and CD3 epsilon in a CD7+ CD5- CD2- case MPO, CD3 epsilon, and CD3 delta in a CD7+ CD5+ CD2- case suggested the presence of some overlapping phase for T- and myeloid-lineage commitment during immature stages of differentiation. This helps understand the conversion of some T-ALL/LBL cases to acute myeloblastic leukemia (AML).(ABSTRACT TRUNCATED AT 400 WORDS)

Acute Disease↗