Biomedical subjects

A Sato

Publications and source records attributed to A Sato.

At least 343 records · Page 19Linked to original sources

PubMed1998

[Pain management in home hospice care].

Among 35 cases with terminal home care cancer patients, 23 (65.7%) cases developed pain. Twenty of these cases (87%) were treated with morphine. MS-contin and Anpec (suppositorium) were given to the patients. The two forms were jointly administered in 20% of them. NSAIDS and other adjuvant analgesics were given to 85% of them. Average dose of morphine were 173.5 +/- 357.5 mg. Adverse morphine side effects were treated with medication. In any case morphine administration was not discontinued due to its adverse effects. Some 82% of the patients died at home. No case dropped out of home care due to unsuccessful pain management. Successful pain management is necessary to implement home terminal care, and both patient and family should fully understand the status and prognosis of the incurable disease. Moreover, medical professionals (home care doctors, home care nurses and hospital doctors) should collaborate to form the temporal, adequate and seamless networking in caring and supporting terminal patients and their families.

Feasibility Studies↗

PubMed1998

[Interstitial pneumonia preceding systemic sclerosis].

We describe a 57-year-old man with interstitial pneumonia associated with systemic sclerosis. About 3 years prior to the appearance of distinctive signs of systemic sclerosis, he was admitted to our hospital with a chronic dry cough. A chest roentgenogram on admission revealed reticulonodular shadows in both lung fields. There were no abnormal laboratory findings. Open lung biopsy specimens revealed patterns indicative of usual interstitial pneumonia, and myxomatous connective tissue within the lumen of the airways. Skin biopsy specimens showed heightened levels of collagen in the dermis, a finding consistent with systemic sclerosis. The patient was given a diagnosis of lung involvement preceding systemic sclerosis despite the absence of concurrent skin symptoms.

Cryptogenic Organizing Pneumonia↗

PubMed1997

RTX toxins recognize a beta2 integrin on the surface of human target cells.

Actinobacillus actinomycetemcomitans leukotoxin and Escherichia coli alpha-hemolysin are RTX toxins that kill human immune cells. We have obtained a monoclonal antibody (295) to a cell surface molecule present on toxin-sensitive HL60 cells that can inhibit cytolysis by both RTX toxins. Utilization of this monoclonal antibody for immunoaffinity purification of detergent-solubilized target cell membranes yielded two polypeptide chains of approximate molecular masses of 100 and 170 kDa. Microsequencing of tryptic peptides from the two proteins showed complete homology with CD11a and CD18, the two subunits of the beta2 integrin, lymphocyte function-associated antigen 1 (LFA-1). Anti-CD11a and CD18 monoclonal antibodies also inhibited RTX toxin-mediated cytolysis. Direct binding experiments demonstrated the ability of an immobilized RTX to bind LFA-1 heterodimers present in a detergent lysate of human HL60 target cells. Transfection of CD11a and CD18 integrin genes into a cell line (K562) that is not sensitive to either RTX toxin resulted in LFA-1 expressing cells, KL/4, that were sensitive to both toxins. These experiments identify LFA-1 as a cell surface receptor that mediates toxicity of members of this family of pore-forming toxins.

Amino Acid Sequence↗

PubMed1997

Central effects of (5RS, 1'SR)-5-benzyl-3-(3'-morpholino-1'-phenylpropyl)-1,3-oxazolidin-2 -one monofumarate on the function of the bladder and periurethral skeletal muscle in anesthetized rats.

The effects of a newly developed drug for incontinence, (5RS, 1'SR)-5-benzyl-3-(3'-morpholino-1'-phenylpropyl)-1,3-oxazolidin-2- one monofumarate (NC-1800), on bladder and periurethral skeletal muscle functions were tested in urethane-anesthetized rats. When the bladder pressure was low, i.v. administration of NC-1800 at doses of 4 to 16 mg/kg induced dose-dependent increases of vesical pressure associated with increases in pelvic efferent nerve activity. When the bladder was expanded, the same administration of NC-1800 induced dose-dependent inhibitions of both vesical micturition contractions and rhythmic pelvic burst discharges. Hypogastric efferent nerve activity was not affected. The periurethral electromyogram (EMG) activity was excited when the bladder was contracted, and EMG activity was inhibited when the bladder was relaxed by NC-1800. Pelvic ganglionic transmission, neuromuscular transmission of both bladder and urethra, and muscle contractility itself of bladder and urethra were not affected by NC-1800. These results suggest that NC-1800 modulates the functions of the bladder and urethra by influencing pelvic and pudendal nerve activity via the central nervous system.

Anesthesia↗

PubMed1997

Cystine knot of the gonadotropin alpha subunit is critical for intracellular behavior but not for in vitro biological activity.

The common alpha subunit of glycoprotein hormones contains five disulfide bonds. Based on the published crystal structure, the assignments are 7-31, 59-87, 10-60, 28-82, and 32-84; the last three comprise the cystine knot, a structure also seen in a variety of growth factors. Previously, we demonstrated that the efficiency of secretion and the ability to form heterodimers by alpha subunits bearing single cysteine residue mutants in the cystine knot were significantly reduced. These results suggested that the cystine knot is critical for the intracellular integrity of the subunit. To assess if the presence of the free thiol affected the secretion kinetics, we constructed paired cysteine mutants of each disulfide bond of the alpha subunit. The secretion rate for these monomers was comparable with wild type except for the alpha-10-60 mutant, which was 40% lower. The recovery of the alpha7-31 and alpha59-87 mutants was greater than 95%, whereas for the cystine knot mutants, it was 20-40%. Co-expression of the wild-type chorionic gonadotropin beta subunit with double cysteine mutants did not enhance the recovery of alpha mutants in the media. Moreover, compared with wild-type, the efficiency of heterodimer formation of the alpha10-60 or alpha32-84 mutants was less than 5%. Because subunit assembly is required for biological activity, studies on the role of these disulfide bonds in signal transduction were not possible. To bypass the assembly step, we exploited the single chain model, where the alpha and beta subunits are genetically fused. The recovery of secreted tethered gonadotropins bearing mutations in the cystine knot was increased significantly. Although dimer-specific monoclonal antibodies discriminated the conformation of single chain alpha10-60 and alpha32-84 mutants from the native heterodimer, these mutants were nevertheless biologically active. Thus, individual bonds of cystine knot are important for secretion and heterodimer formation but not for in vitro bioactivity. Moreover, the data suggest that the native heterodimer configuration is not a prerequisite for receptor binding or signal transduction.

Amino Acid Sequence↗

PubMed1997

Effect of stimulation of nicotinic cholinergic receptors on cortical cerebral blood flow and changes in the effect during aging in anesthetized rats.

The effect of intravenous injection of nicotine on cortical cerebral blood flow (CBF) was examined in urethane anesthetized rats. Nicotine (3-30 microg/kg) increased cortical CBF, independent of mean arterial pressure. This response was attenuated to about a half of the control one after lesioning the nucleus basalis of Meynert (NBM) bilaterally. The response was not significantly influenced after blocking the muscarinic receptors, but was abolished after blocking the nicotinic receptors in the parenchyma of the brain. It is concluded that the nicotine-induced cortical vasodilation was mediated by activation of the nicotinic receptors in the NBM and also in the cortex of the brain. The threshold dose of nicotine for increasing cortical CBF was shifted in aged rats of 23-26 months, and the nicotine-induced increase in cortical CBF was much reduced in aged rats of 32-36 months. Activation of nicotinic receptors in the brain may be of therapeutic value in aged subjects in facilitating the cholinergic neural vasodilative system.

Aging↗

PubMed1997

CXCR4/fusin is not a species-specific barrier in murine cells for HIV-1 entry.

Since some murine cells expressing human CD4 fail to internalize HIV-1, another block was thought to be located at the level of viral entry in addition to CD4. Recently, CXCR4 was shown to function as a coreceptor for T cell line-tropic HIV-1 entry. Here we demonstrated that cells expressing murine CXCR4 and human CD4 fused with cells expressing the env proteins derived from T cell line-tropic HIV-1 and were infected with T cell line-tropic HIV-1 strains. In contrast, the same cells were not infected with chimeric clones constructed by substitution of monocyte- or macrophage-tropic strain-derived env region or V3 region into T cell line-tropic HIV-1, indicating V3 loop of envelope protein is required for murine CXCR4mediated HIV-1 entry. We conclude that murine CXCR4 is not a species specific barrier to the entry of T cell line-tropic HIV-1.

3T3 Cells↗

PubMed1997

Fatty alcohol synthesis accompanied with chain elongation in liver peroxisomes.

We have reported that the fatty alcohol destined to form the 1-alkenyl group of plasmalogen is synthesized as a nascent fatty alcohol within peroxisomes, from acetyl-CoA supplied by beta-oxidation. The present experiment was designed to confirm this peroxisomal fatty alcohol synthesis by using [1-14C]acetyl-CoA. Rats were fed for 2 weeks on chow containing 0.25% clofibrate, as a peroxisome proliferator. Peroxisomes were prepared from the rat liver to more than 85% purity, and incubated with [1-14C]acetyl-CoA in order to investigate suitable conditions for fatty alcohol biosynthesis. Dodecanoyl-CoA was the most suitable primer, and the reaction required NADH and/or NADPH as a reducing factor; NAD+ or NADP+ greatly inhibited the reaction, even if a significant amount of the reduced form still remained. The reaction proceeded linearly with respect to peroxisomal protein concentration and incubation time. Under the optimum conditions for fatty alcohol synthesis, 1 mg of peroxisomal protein could produce approx. 0.7 nmol of fatty alcohol per hour, and the main product was hexadecanol.

Acetyl Coenzyme A↗

PubMed1997

Cell display library for gene cloning of variable regions of human antibodies to hepatitis B surface antigen.

A novel cell display system was developed for cloning the variable region (V) genes of antigen-specific human antibodies. The system is based on an antibody library displayed on the surface of COS cells, using a plasmid vector designed to direct expression of membrane-bound antibodies. COS cells expressing antigen-specific antibodies were separated using a flow cytometer for their binding to a fluorescent dye-labeled antigen. To test the performance of this system. We cloned V genes of 4 antibodies directed against hepatitis B surface antigen (HBsAg) from a library prepared from peripheral blood lymphocytes of a vaccinated donor. These membrane-bound anti-HBsAg antibodies were easily converted to soluble forms, all of which showed a size similar to human serum IgG in SDS-PAGE and the same specific binding to HBsAg as membrane-bound forms in ELISA. All VH and VK gene segments of the 4 clones isolated in this study belonged to VHIII and VKI subgroups, respectively. These findings demonstrate the potential and selection capabilities of our cell display system for cloning the V genes of antigen-specific human antibodies.

Amino Acid Sequence↗

PubMed1997

The biologic action of single-chain choriogonadotropin is not dependent on the individual disulfide bonds of the beta subunit.

Disrupting disulfide loops in the human chorionic gonadotropin beta subunit (CGbeta) inhibits combination with the alpha subunit. Because the bioactivity requires a heterodimer, studies on the role of disulfide bonds on receptor binding/signal transduction have previously been precluded. To address this problem, we bypassed the assembly step and genetically fused CGbeta subunits bearing paired cysteine mutations to a wild-type alpha (WTalpha) subunit. The changes altered secretion of the single-chain mutants which parallel that seen for the CGbeta monomeric subunit. Despite conformational changes in CG disulfide bond mutants (assayed by gel electrophoresis and conformationally sensitive monoclonal antibodies), the variants bind to the lutropin/CG receptor and activated adenylate cyclase in vitro. The data show that the structural requirements for secretion and bioactivity are not the same. The results also suggest that the extensive native subunit interactions determined by the cystine bonds are not required for signal transduction. Moreover, these studies demonstrate that the single-chain model is an effective approach to structure-activity relationships of residues and structural domains associated with assembly of multisubunit ligands.

Chorionic Gonadotropin↗

PubMed1997

Adrenomedullin stimulates cAMP accumulation and inhibits atrial natriuretic peptide gene expression in cardiomyocytes.

Adrenomedullin (ADM) is a novel vasodilating and natriuretic peptide which may play an important role in cardiovascular regulation. In neonatal cardiomyocyte cultures we have shown that ADM leads to dose-dependent inceases in cAMP accumulation and subsequent inhibition of atrial natriuretic peptide (ANP) gene expression and secretion. Forskolin-mediated elevation of intracellular cAMP levels led to a qualitatively similar inhibitory effect on both ANP gene expression and secretion. These data show that ADM has direct effects on expression of ANP in the cardiomyocyte by a mechanism that may involve the activation of adenylate cyclase, lending further support to the hypothesis that ADM may act in vivo as an important endocrine or paracrine modulator of cardiovascular function.

Adrenomedullin↗

PubMed1997

Fine structure of tuft cells of the main excretory duct epithelium in the rat submandibular gland.

BACKGROUND: Tuft cells, which are characterized by long microvilli with prominent rootlets and by vesicular and tubular profiles, are present in the mucosal epithelium of a number of hollow organs, including the main excretory duct of the rat submandibular gland. Despite their widespread occurrence, little is known of their function. METHODS: Main excretory ducts of the submandibular gland were obtained from 20 male Wistar rats and prepared for electron microscopic examination. Specimens also were subjected to various histochemical procedures, including HRP (horseradish peroxidase) uptake, the demonstration of catalase in peroxisomes, glycoconjugate cytochemistry, and ruthenium red staining. RESULTS: The features of the tuft cells in the MED (main excretory duct) basically were similar to those described in other organs. However, for the first time it was observed that in the submicrovillus zone and intermicrovillus space, there were many membrane-bound electron-dense granules, which resemble the so-called glycocalyceal bodies found on the apical surface of normal and neoplastic intestinal-type epithelial cells. Hypolemmal nerve terminals were seen to be in contact with the basal portion of tuft cells. After injection of HRP, reaction products were observed on the luminal surface of the microvilli, but not within the vesicles. Vesicles and tubules in the supranuclear cytoplasm exhibited a positive cytochemical reaction for glycoconjugates. The surface coat of tuft cell microvilli was stained with ruthenium red, but the vesicles and tubules in the supranuclear cytoplasm remained unstained. CONCLUSIONS: Our observations suggest that the tuft cells may engage in secretory activity in addition to reception.

Animals↗

PubMed1997

A competitive RT-PCR method for the quantitative analysis of cytokine mRNAs in mouse tissues.

The authors describe the design and validation of a competitive RT-PCR method for the efficient and reproducible quantitation of mRNA molecules of IFN-gamma, TNF-alpha, IL-4 and IL-10 in mouse spleen RNA extracts. Before being subjected to RT-PCR, the RNA extracts were supplemented with internal control RNAs (IC-RNAs), which were constructed by inserting DNA fragments in the cDNA of the respective cytokines. The efficiency of amplification of the target and the IC-RNA was shown to remain equal over a wide range of cycle numbers. Reproducibility was such that differences in mRNA contents that were greater than 17% could be detected between two RNA samples run in parallel. Normal mouse spleen tissue was found to contain 10(7)-10(8) molecules of TNF-alpha, IFN-gamma, IL-4 and IL-10 mRNA per micrograms total RNA extracted. Injection of animals with anti-CD3 antibody, a well-known cytokine inducer, resulted in a moderate increase in TNF-alpha and IL-10 mRNA levels (14- and 24-fold, respectively), and in a substantially greater increase in the levels of mRNA for IL-4 and IFN-gamma (199- and 851-fold, respectively). These results demonstrate an accurate and reliable quantitation of cytokine mRNA levels in animal tissues.

Animals↗

PubMed1997

Dose- and route-dependent alterations in metabolism and toxicity of chemical compounds in ethanol-treated rats: difference between highly (chloroform) and poorly (carbon tetrachloride) metabolized hepatotoxic compounds.

The dose and route dependency of the metabolism and the toxicity of chloroform (CHCl3) and carbon tetrachloride (CCl4) was investigated in ethanol-treated rats. Rats that had been kept on either an ethanol (containing ethanol at 2 g/rat/day) or a control (containing no ethanol) liquid diet for 3 weeks were challenged with CHCl3 or CCl4 by inhalation (0, 50, or 500 ppm x 6 hr), or by p.o. or i.p. administration (0, 0.105, or 1.675 mmol/kg). Ethanol consumption, which increased the in vitro metabolism of both compounds six- to sevenfold, affected the metabolism and toxicity of CCl4 differently from those of CHCl3. Ethanol increased the metabolism and toxicity of CHCl3 at 500 ppm only, whereas it increased the metabolism and toxicity of CCl4 at either 50 or 500 ppm. In addition, the effect of ethanol consumption differed between CHCl3 and CCl4 depending on the route of administration (p.o. or i.p.) and the dose (0.105 or 1.675 mmol/kg). For the p.o. route, ethanol increased the metabolism and toxicity of both compounds at either dose. For the i.p. route, however, ethanol increased the metabolism and toxicity of the high dose of CHCl3 only, but of both CCl4 doses. The dose- and route-dependent differences in the effect of enzyme induction on the metabolism and toxicity between CHCl3 and CCl4 can be explained by a supposition that the hepatic blood flow rate-limits the metabolism of a low dose of CHCl3 (perfusion-limited metabolism), whereas the metabolic capacity of the liver limits the metabolism of CCl4 (capacity-limited metabolism) irrespective of dose.

Administration, Inhalation↗

PubMed1997

Retinal projections to the accommodation-related area in the rostral superior colliculus of the cat.

Results of previous studies have indicated that the rostral superior colliculus (SC) plays an important part in the control of accommodation. The present study was carried out to investigate retinal projections to the accommodation-related area in the rostral SC. We injected WGA-HRP into the accommodation-related area in the rostral SC of the cat, where accommodative responses were elicited by stimulation with weak currents of less than 20 microA. Following injection of WGA-HRP into the accommodation-related area in the rostral SC, retrogradely labeled ganglion cells were observed mainly in the area centralis. Projections from the contralateral eye were denser than those from the ipsilateral eye. Almost all retrogradely labeled cells were classified as gamma-cells owing to their small cell-body diameters and thin dendrites, although a few were classified as alpha-cells. These findings suggest that the accommodation-related area in the rostral SC is located in the portion corresponding to the area of representation of the central visual field and receives mainly gamma-cell projections.

Accommodation, Ocular↗

PubMed1997

Mixed connective tissue disease associated with idiopathic portal hypertension and chronic thyroiditis.

We report a patient with mixed connective tissue disease (MCTD) associated with idiopathic portal hypertension (IPH) and chronic thyroiditis. The patient was a 68-year-old Japanese woman who was admitted to our hospital for treatment of bleeding esophageal varices. She had previously exhibited Raynaud's phenomenon and had had arthritis for about 30 years. She also had had high titers anti-U1 of ribonucleoprotein (RNP) anti-single strand-DNA autoantibodies for 2 years, and had been diagnosed with MCTD 1 year previously. The bleeding from esophageal varices was successfully stopped by endoscopic injection sclerotherapy. Results of laboratory examinations, imaging examinations, and laparoscopy, including liver biopsy, indicated that the esophageal varices were caused by portal hypertension due to IPH. The patient also had a diffusely firm and enlarged goiter and hypothyroidism, and she exhibited anti-thyroid microsomal antibodies and anti-thyroglobulin antibodies, she was diagnosed as having a complication of chronic thyroiditis. This association of MCTD, IPH, and chronic thyroiditis is quite rare and provides a unique opportunity to observe immunological involvement in the pathogenesis of IPH.

Aged↗

PubMed1997

Time courses of hepatic injuries induced by chloroform and by carbon tetrachloride: comparison of biochemical and histopathological changes.

The relationship was investigated between biochemical and morphological changes in chloroform (CHCl3)- and carbon tetrachloride (CCl4)-induced liver damage. The time courses of hepatic microsomal cytochrome P450 (CYP) content, hepatic microsomal CYP2E1 activity, hepatic reduced glutathione (GSH) content, plasma alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities were examined in relation to the liver morphology in rats orally treated with CHCl3 or CCl4 (3.35 mmol/kg). The CYP content and the activity of CYP2E1 markedly decreased in the CCl4-treated rats 3 h after treatment compared to much lower decreases in the CHCl3-treated rats. The hepatic GSH content was decreased to a similar extent in both groups of rats at 3 h after treatment; in the CCl4-treated rats, the GSH content continued to decrease, reaching a minimum at 24 h and without attaining the normal level at 72 h after treatment. By contrast, hepatic GSH content in the CHCl3-treated rats began to increase from 6 h, attaining complete recovery 48 h after treatment. Plasma ALT and AST activities were significantly elevated by CCl4 as early as 3 h after treatment, while the activities in the CHCl3-treated rats did not increase until 6 h after treatment. In both groups of rats, ALT and AST activities reached a maximum at 24 h, and gradually decreased, remaining at abnormal levels at 72 h. Hepatic cells in the CCl4-treated rats were found to be necrotic as early as 3 h post-treatment, whereas few or no morphological changes appeared in the liver of CHCl3-treated rats. The extent of necrosis was at a maximum 24 h after treatment in both CHCl3- and CCl4-treated rats. In addition, some necrotic cells remained in the liver of CCl4-treated rats 72 h after treatment, while the necrosis in the CHCl3-treated rats was almost negligible. The present results indicate that almost the same time-courses of biochemical and morphological changes were followed in rats of both the CHCl3- and CCl4-treated groups.

Administration, Oral↗

PubMed1997

Class I mhc genes of cichlid fishes: identification, expression, and polymorphism.

Cichlid fishes of the East African Rift Valley lakes constitute an important model of adaptive radiation. Explosive speciation in the Great Lakes, in some cases as recently as 12 400 years ago, generated large species flocks that have been the focus of evolutionary studies for some time. The studies have, however, been hampered by the paucity of biochemical markers for phylogenetic reconstruction. Here, we describe a set of markers which should help to alleviate this problem. They are the class I genes of the major histocompatibility complex. We provide evidence for the existence of at least 17 class I loci in cichlid fishes, and for extensive polymorphism of three of these loci. Since the polymorphism has a trans-species character, it will be possible to use it in investigating the founding events of the individual species. The sequences of the cichlid class I fishes support the monophyly of actinopterygian fish on the one hand, and of tetrapods on the other.

Animals↗