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Biomedical subjects

N Satoh

Publications and source records attributed to N Satoh.

At least 199 records · Page 11Linked to original sources
PubMed1995

Clinical characteristics of hepatitis C virus-associated retinopathy.

The morbidity rate for retinopathy of unknown origin was significantly higher (P < 0.001) in the chronic hepatitis C group, 27 (31.8%) of 85 cases, than in the control group, 6 (6.0%) of 100 cases. Among hepatitis C virus (HCV)-associated retinopathy patients, 6 cases (22.2%) were aware of ocular subjective symptoms, retinopathy recurred in 8 (29.6%) cases, binocular retinopathy occurred in 14 (51.9%) cases, and retinopathy related to liver dysfunction, in 13 (81.3%) of 16 tested cases. HCV-associated retinopathy involved hemorrhage at the posterior pole retina in 21 (77.8%), cotton-wool patches in 9 (33.3%), and hemorrhage at the peripheral retina in 7 (25.9%) cases. Sequelae occurred in only one case. Retinopathy worsened or recurred in all 7 cases treated with interferon. The risk factors for HCV-associated retinopathy were mild thrombocytopenia (P < 0.001), long-term hepatitis illness (P < 0.005), advanced age (P < 0.02), concurrence with liver cirrhosis (P < 0.02), history of systemic hypertension (P < 0.05), and female gender (P < 0.05).

Adult↗
PubMed1994

Cardiovascular effects of YM099, a novel K+ channel opener, in anesthetized and conscious dogs.

Cardiovascular effects of a newly synthesized benzoxadiazol derivative K+ channel opener, YM099, 2-(7,8-dihydro-6,6-dimethyl-6H-[1,4]oxazino[2,3- f][2,1,3]benzoxadiazol-8-yl) pyridine N-oxide, were evaluated in dogs. In pentobarbital-anesthetized dogs, YM099 (1-10 micrograms/kg i.v.), similarly to levcromakalim (1-10 micrograms/kg i.v.), dose dependently increased coronary artery blood flow, max.d p/dt and cardiac output, and decreased total peripheral resistance and mean blood pressure, with a small increase in heart rate. These vasodilator effects were antagonized by glibenclamide (3 mg/kg i.v.). Interestingly, YM099 selectively increased coronary artery blood flow, although it increased carotid, coronary, mesenteric and renal artery blood flows and cardiac output. In addition, YM099 (1-10 micrograms/kg i.v.) increased large conductive coronary artery vessel diameter as well as coronary artery blood flow. In conscious dogs, YM099 (100 micrograms/kg i.v.) also increased the diameter of large conductive and small resistive coronary arteries. In conclusion, YM099 is a potent vasodilator agent, with particularly pronounced effects on the coronary artery. These effects of YM099 may be mediated by the opening of ATP-sensitive K+ channels.

Adenosine Triphosphate↗
PubMed1994

Details of the evolutionary history from invertebrates to vertebrates, as deduced from the sequences of 18S rDNA.

Almost the entire sequences of 18S rDNA were determined for two chaetognaths, five echinoderms, a hemichordate, and two urochordates (a larvacean and a salp). Phylogenetic comparisons of the sequences, together with those of other deuterostomes (an ascidian, a cephalochordate, and vertebrates) and protostomes (an arthropod and a mollusc), suggest the monophyly of the deuterostomes, with the exception of the chaetognaths. Chaetognaths may not be a group of deuterostomes. The deuterostome group closest to vertebrates was the group of cephalochordates. Ascidians, larvaceans, and salps seem to form a discrete group (urochordates), in which the early divergence of larvaceans is evident. These results support the hypothesis that chordates evolved from free-living ancestors.

Animals↗
PubMed1994

Tissue factor in plasma of patients with disseminated intravascular coagulation.

Recently it has been shown that tissue factor (TF), an important trigger for initiating blood coagulation, is present in the circulating plasma. In order to assess the clinical implications of TF in plasma, plasma concentration of TF was quantitated in 65 patients with disseminated intravascular coagulation (DIC). The mean concentration of plasma TF was elevated in patients with DIC at presentation as compared with healthy subjects (446 +/- SD 536 pg/ml vs. 138 +/- 51 pg/ml, P < 0.001). Abnormally high levels were found only in 46.2% of the patients, predominantly in patients with non-hematological solid tumors and acute leukemia. Plasma TF did not correlate with hemostatic markers of DIC such as thrombin-antithrombin III complex, prothrombin fragment 1 + 2, plasma-alpha 2-plasmin inhibitor complex, FDP, D-dimer, or fibrinogen. Serial determinations of plasma TF demonstrated that plasma TF changes roughly in parallel with the course of DIC in most patients with elevated TF at presentation of DIC. These findings suggest that plasma TF is potentially valuable for monitoring the progress of DIC in a limited population of patients.

Disseminated Intravascular Coagulation↗
PubMed1994

Development of egg fragments of the ascidian Ciona savignyi: the cytoplasmic factors responsible for muscle differentiation are separated into a specific fragment.

The eggs of ascidians contain cytoplasmic determinants responsible for differentiation of larval muscle cells. However, the molecular nature and mode of action of muscle determinants are unknown at present. To establish an appropriate experimental system for studying muscle determinants, we have devised a method for separating the determinants into specific egg fragments. The treatment of unfertilized eggs of Ciona savignyi with cytochalasin B followed by centrifugation yielded (1) a large, nucleated red fragment, (2) a small, enucleated black fragment, (3) a small, enucleated clear fragment, and (4) a small, enucleated brown fragment. When inseminated, only red fragments cleaved and developed into so-called "permanent blastulae," in which the differentiation of epidermal cells was evident. However, when red fragments were fused with black fragments and the fusion products were inseminated, the fusion products showed a remarkable ability to express muscle-specific markers. In addition, the ability of black fragments to promote the expression of muscle-specific markers was evident when the fragments were fused with presumptive-epidermis blastomeres. In contrast, clear and brown fragments showed limited ability to promote muscle differentiation. These results suggest that the muscle determinants are present in unfertilized eggs and that the determinants are concentrated into black fragments and depleted from red fragments. These two fragments may serve as an appropriate experimental system to determine the molecular nature of muscle determinants in ascidian eggs.

Animals↗
PubMed1994

Autonomy of expression of epidermis-specific genes in the ascidian embryo.

An example of developmental autonomy, assessed at the level of expression of tissue-specific genes, was characterized in this study. cDNA clones that corresponded to two different epidermis-specific genes (HrEpiA and HrEpiB) of the ascidian Halocynthia roretzi were isolated. Transcripts of both genes first appeared around the time of gastrulation, suggesting zygotic expression. In the case of HrEpiA, transcripts became undetectable after metamorphosis had begun, while transcripts of HrEpiB were still detectable in juveniles after metamorphosis. In situ hybridization analysis using HrEpiA and B probes gave the following results. (1) All types of partial embryo that originated from blastomeres with epidermal fate from two-, four-, and eight-cell embryos expressed these two epidermis-specific genes. (2) When cleavage was blocked by treatment with cytochalasin B at the one-cell stage, the cleavage-arrested one-celled embryos expressed the two genes. (3) Even when blastomeres with epidermal fate were isolated from two-, four-, and eight-cell embryos and the division of the blastomeres was arrested immediately after isolation, they expressed the two specific genes. These results suggest that the epidermal lineage in the early ascidian embryo is a developmental system with considerable self-sustainability.

Amino Acid Sequence↗
PubMed1994

An ascidian homolog of SEC61 is expressed predominantly in epidermal cells of the embryo.

In eukaryotic cells, SEC61 protein is essential for protein translocation across the endoplasmic reticulum membrane. Because of the ubiquitous nature of the protein, the expression of the corresponding gene(s) during embryogenesis has not received much attention. We found that an ascidian homolog of SEC61 is expressed predominantly in embryonic epidermal cells. A cDNA clone for Halocynthia roretzi SEC61 (HRSEC61) gene contains a single open reading frame that encodes a polypeptide of 475 amino acids. The degree of amino-acid identity was 87% between the ascidian and the dog and 55% between the ascidian and yeast. The HRSEC61 gene was transcribed maternally and zygotically. A low level of the corresponding mRNAs, about 2.3 kb in length, was found in eggs and early embryos. Zygotic mRNAs appeared after the gastrula stage, and the accumulation of the mRNAs was maximal at the neurula and tailbud stages. In situ hybridization of whole-mount specimens demonstrated that, although maternal mRNAs were distributed evenly in eggs and early embryos, the occurrence of zygotic mRNAs was predominant in differentiating epidermal cells. The predominant expression of HRSEC61 in embryonic epidermal cells was determined using cleavage-arrested embryos; those at the 16- or 32-cell stage expressed HRSEC61 in the presumptive epidermal cells of the animal hemisphere.

Amino Acid Sequence↗
PubMed1994

Short upstream sequences associated with the muscle-specific expression of an actin gene in ascidian embryos.

The HrMA4 alpha gene for an embryonic muscle actin of the ascidian Halocynthia roretzi is activated at the gastrula stage in differentiating muscle cells exclusively. The 5' upstream region close to the transcription start site of HrMA4 alpha contains several consensus sequences, which include a TATA box at -30, and E-box at -71, a CArG box at -116, and a cluster of three E-boxes between -150 and -190. When deletion constructs of this region, fused with the bacterial gene for beta-galactosidase (lac-Z), were microinjected into fertilized eggs, the reporter gene was expressed in muscle cells of tailbud embryos. Analyses of the deletion constructs suggested that the 103-bp upstream region is sufficient for the appropriate expression of the gene. However, beta-gal activity was very rarely detectable in the case of 82-bp upstream region and no activity was detected in the case of 72-bp upstream region. Mutations in the proximal E-box sequence did not disturb the muscle-specific expression of the reporter gene. These results suggest that rather short sequences between nucleotides -103 and -72 from the transcription start site are associated with the specific expression of HrMA4 alpha.

Actins↗
PubMed1994

Phylogenetic relationships among extant classes of echinoderms, as inferred from sequences of 18S rDNA, coincide with relationships deduced from the fossil record.

In spite of the rich fossil record and multiple descriptions of morphological and embryological characteristics, the origin and subsequent evolution of echinoderms remain highly controversial issues. Using sequence data derived from 18S rDNA, we have investigated the phylogenetic relationships among five extant classes of echinoderms--namely, crinoids, asteroids, ophiuroids, echinoids, and holothurians. Almost complete sequences of 18S rDNA were determined for one species in each class, and phylogenetic trees were constructed both by the neighbor-joining method and by the maximum-likelihood method, with a hemichordate as an outgroup. The trees constructed by these methods support the hypothesis that the phylum Echinodermata can be subdivided into two subphyla, Pelmatozoa and Eleutherozoa. The class Holothuroidea, which has been the subject of debate with respect to whether the members are primitive or advanced echinoderms, did not occupy a primitive position but had an affinity for the class Echinoidea. Since both trees gave different branching topologies for the order of emergence of asteroids and ophiuroids, it seems likely that these two groups emerged within a very short period of time. A rough estimate of the timing of the divergence of the five classes from the present molecular analysis coincided with that deduced from the fossil record.

Animals↗
PubMed1994

The role of extracellular Ca2+ in carbachol-induced tonic contraction of the pig detrusor smooth muscle.

The role of extracellular Ca2+ in the tonic-contractile response to muscarinic receptor stimulation was investigated in isolated detrusor smooth muscle from the pig urinary bladder. Carbachol (10(-8)-10(-5) M) produced a concentration-dependent contractile response in isolated pig detrusor smooth muscle strips consisting of an initial phasic component followed by a tonic component. During the plateau of the tonic contractions induced by carbachol at the submaximal concentration of 10(-6) M, the inhibiting effects of atropine, EGTA, nifedipine (a voltage-dependent calcium channel antagonist), H-7 [a protein kinase C (PKC) inhibitor] and YM934 (a potassium channel opener) on the contractions were evaluated. Atropine (10(-10)-3 x 10(-8) M) concentration-dependently inhibited the tonic contractions induced by carbachol. In the same experimental conditions, EGTA (4 mM) and nifedipine (10(-9)-3 x 10(-7) M) depressed the tonic contractions in a concentration-dependent manner as did H-7 (10(-5)-3 x 10(-5) M) and YM934 (10(-8)-10(-6) M). However, H-7 (10(-5)-3 x 10(-5) M) and YM934 (10(-6) M) were very weak in inhibiting the contractions induced by KCl (50 mM) in isolated pig detrusor smooth muscle strips. These results suggest that the tonic-contractile response induced by carbachol in pig detrusor smooth muscle strips is dependent mainly on depolarization of the cell membranes and an influx of extracellular Ca2+, and also suggest that this depolarizing response may be due to inactivation of ATP-sensitive potassium channels through muscarinic activation of PKC.

Animals↗
PubMed1994

Endogenous components of event-related potential appearing during NREM stage 1 and REM sleep in man.

Information processing in the brain during sleep was studied by analyzing the evoked cortical response to auditory stimulations presented in the odd-ball paradigm. Eight subjects were examined in different sleep stages. The subjects could provide the correct behavioral response to the auditory stimulation by pressing a key button in the light part of stage 1 of NREM sleep, just succeeding to the waking state, but none of the subjects could give the correct behavioral response in the other sleep stages. In the deep part of stage 1 of NREM sleep and REM sleep, a cortical potential corresponding to P300, the endogenous component of the event-related potential (ERP) recorded in the waking state, was recorded in 6 of the 8 subjects in spite of the absence of the behavioral response. In stages 2, 3 and 4 of NREM sleep, emergence of this endogenous component of ERP could not be confirmed. The present findings provide electrophysiological evidence indicating that selective information processing corresponding to sensory discrimination of auditory stimuli is actively performed in stage 1 of NREM sleep and REM sleep.

Adult↗
PubMed1994

Perceived pitch of complex FM-AM tones--pitch determination process of vibrato sounds.

Pitch-matching experiments were conducted to clarify the pitch determination process of complex FM-AM tones which consist of components whose frequency and amplitude are simultaneously modulated. The pitch is higher when FM and AM of each component are in phase than when they are out of phase. The pitch shift induced by the phase difference between FM and AM of each component becomes larger as its relative power increases. These experimental results suggest that the pitch of complex FM-AM tones is determined as follows: A complex FM-AM tone is resolved into each FM-AM component by the auditory filter bank. The spectral pitch of each FM-AM component is determined by a loudness-weighted pitch averaging processes. The central pattern recognizer determines the pitch of complex FM-AM tones by integration of virtual pitches derived from the spectral pitches.

Adult↗
PubMed1994

[Four cases of olfactory neuroblastoma treated with craniofacial surgery].

We report 4 cases of olfactory neuroblastoma with anterior cranial fossa extension treated by craniofacial surgery. Three patients have been alive and well for 4 years, 1 year and 11 months after the initial treatment without major surgical complications but one patient died of local recurrence 11 months after treatment. Multidisciplinary surgery for olfactory neuroblastoma with intracranial extension permits radical tumor excision and reconstruction of the anterior skull base. This one-stage procedure combining neurosurgery and plastic surgery with pre or post-operative radiotherapy is considered to be essential for eradicating this tumor.

Adult↗
PubMed1994

[Chronic cold agglutinin disease accompanied with an increase of CD20+/CD5+ cells; a case report].

A 61-year-old male complained of acrocyanosis and dark urine when exposing to cold temperatures. This had continued for several years. His physical examinations showed neither lymphadenopathy nor hepatosplenomegaly. Laboratory findings were as follows; RBC 305 x 10(4)/microliters, Hb 10.3 g/dl, reticulocytes 4.32%, platelets 27.3 x 10(4)/microliters, WBC 7,400/microliters with 50% lymphocytes, and a high cold agglutinin titer (2,048-fold) with anti-I specificity. Bone marrow smear preparations showed erythroid hyperplasia and increase of lymphocytes (52%). Immunophenotypic analysis showed an increase of CD20+/B-lymphocytes in peripheral blood (32.6%) and in bone marrow, and 94% of these cells co-expressed CD5. Most B-lymphocytes expressed surface IgM-lambda, suggesting a monoclonal proliferation of B-lymphocytes. At this point we diagnosed cold agglutinin disease (CAD) because there was no evidence of lymphoma, and the absolute number of peripheral blood lymphocytes was lower than the criteria of chronic lymphocytic leukemia (CLL) proposed by the International Workshop (1989). However, there still remains the possibility of the transitional form between "idiopathic" CAD and B-CLL or lymphoma.

Anemia, Hemolytic, Autoimmune↗
PubMed1994

Chromium-induced carcinoma in the nasal region. A report of four cases.

The carcinogenicity of chromium is well established in chromium-induced lung cancer. As of yet, however, there have been only few reports of head-and-neck cancer induced by chromium. We report four cases of carcinoma in the nasal region which seemed to be induced by chromium. All patients have worked at the same chromate factory for 19 to 32 years. The first patient has suffered from squamous cell carcinoma of the left nasal cavity, starting 11 years after his retirement. He received radiotherapy followed by surgery. A malignant fibrous histiocytoma occurred in his left upper gingiva in a previously irradiated region, 7 years after the previous treatment. Surgery and chemotherapy for palliation failed to control the tumour, and he eventually expired. The other three patients underwent lobectomy for lung cancer. In cases 2 and 3, the tumour occurred in the left nasal cavity six and ten years, respectively, each after the lobectomy. In case 4, the tumour arose from the nasopharynx 15 years after the lobectomy. These patients are alive and well without any sign of tumour. The presented cases seem to be induced by long-term exposure to chromium. We conclude that regular physical examination of chromate workers is mandatory for the early detection not only of lung cancer but also of head-and-neck cancer.

Aged↗