Biomedical subjects

K Murakami

Publications and source records attributed to K Murakami.

At least 145 records · Page 8Linked to original sources

PubMed2000

[Isolation of Mycobacterium avium complex from the "24-hour bath"].

The "24-HOUR BATH" is an apparatus which circulates the bath water, keeps it clean and warm, and makes it possible to take a bath at any time during the day or night. It consists of apparatus for cleaning (sponge or mesh filter and filter material), heating (ceramic heater), and sterilizing (UV lamp). Recently, three cases of skin disease due to M. avium infection in private homes, in which "24-HOUR BATH" water was suspected to be the source of infection, have been reported. We attempted to isolate M. avium complex from the water (32 specimens), sponge filter (29 specimens), and filter material (32 specimens) of the "24-HOUR BATH". One hundred-ml samples of bath water, and 50-ml samples of rinse from a sponge filter or filter material were centrifuged at 3000 rpm for 20 min. Sediment was suspended in distilled water and a smear was prepared, and then digested and decontaminated with 2% sodium hydroxide. The processed specimens were cultured on 2% Ogawa medium containing ofloxacin (1 microgram/ml) and ethambutol (2.5 micrograms/ml) for 8 weeks at 37 degrees C. Positive smears were 3 (9.4%), 25 (86.2%) and 25 (78.1%) specimens from the water, sponge and filter material, respectively. A few bacterial clumps were observed, especially in the sponge specimens. The number of positive culture was 5 (15.6%), 24 (82.8%) and 25 (78.1%) from the water, sponge and filter material, respectively. Among them the number of Runyon's Group III-positive cultures was 5 (100%), 22 (91.7%) and 20 (80%) in the water, sponge, and filter material specimens, respectively. In most cases, cultures were positive for both the sponge and filter material specimens. All of the Group III mycobacteria were smooth, grew at 28, 37, 42, and 45 degrees C, negative for niacin, nitrate reductase, semiquantitative catalase, urease and Tween80 hydrolysis, and positive for 68 degrees C catalase. All of the strains reacted with M. avium complex AccuProbe and M. avium AccuProbe, but none of the strains reacted with M. intracellulare AccuProbe. Therefore, all the Group III isolates were identified as M. avium by the culture, biochemical and genetical characteristics.

Baths↗

PubMed2000

[The virulence for mice of newly described mycobacterial species].

The virulence for mice of some newly described slowly growing mycobacterial species, M. intermedium DSM 44049 (Group I), M. lentiflavum ATCC 51985 and M. interjectum ATCC 51457 (Group II), M. genavense ATCC 51233, M. celatum ATCC 51131, M. branderi ATCC 51788 and M. conspicuum DSM 6333 (Group III) was compared with the virulence of M. intracellulare N-260 (virulent strain). 10(6) CFU cultured in Middlebrook 7H9 medium were given i.v. to the BALB/c mice. Infected animals were sacrificed after one day and 56 days, and observed for the incidence and/or degree of gross lesions of visceral organs. The bacterial load (CFU) in tissue homogenates of the lungs and spleen was counted using 7H11 agar plates. Macroscopically, marked enlargement of the spleen and numerous small whitish nodules in the lungs of mice infected with M. intracellulare were noted, whereas with other test strains no gross disease in the lungs and slight enlargement of the spleen of mice infected with M. genavense and M. branderi were noted. The average log CFU in the lungs and spleen 56 days after the infection was in the order as follows: M. intracellulare (5.90 and 7.57, respectively), M. genavense (4.35, 7.15), M. celatum (5.01, 6.00), M. branderi (4.09, 6.33), M. conspicuum (3.11, 5.10), M. intermedium (2.26, 4.19), M. lentiflavum (1.70, 3.91), and M. interjectum (1.43, 2.93). Microscopically, granulomatous lesions mainly consisted of macrophages with acid-fast bacilli were found in the alveolar walls and splenic red pulp of mice infected with M. intracellulare. No histopathological changes were produced in the lungs of any of mice infected with other test strains, and some milder features were revealed in the spleen of mice infected with M. genavense, M. branderi and M. celatum. Thus, we concluded that all of the test strains of the newly described nontuberculous slowly growing mycobacteria were less virulent for mice than were M. intracellulare.

Animals↗

PubMed2000

Cloning and characterization of the iutA gene which encodes ferric aerobactin receptor from marine Vibrio species.

The iutA gene from marine Vibrio species SD004, which encoded a ferric aerobactin receptor for the uptake of iron(III), was cloned onto a multicopy plasmid, pUC 18, in Escherichia coli. Identification of the positive clone was achieved on the basis of its deferrization activity and was detected as a halo formation on the chrome azurol S (CAS)-containing selective plate. Nucleotide sequence analysis of the cloned DNA fragment revealed an open reading frame (ORF) which encoded a polypeptide of 706 amino acid residues, and the deduced molecular mass of this polypeptide was 77.906 kD. The amino acid sequence showed a 41% homology with that of the lutA protein from E. coli. The cloned gene was iutA, which encoded the ferric aerobactin receptor. Another incomplete ORF was found 100 bp upstream of the iutA gene, which was homologous (31 out of 49 amino acids) with the C-terminal region of the luc D protein of E. coli. It is suggested that aerobactin biosynthesis and the transport genes are located tandemly on the Vibrio chromosome and may form an aerobactin operon.

Amino Acid Sequence↗

PubMed2000

[Treatment by corticosteroid and plasma exchange in 5 cases of renal cholesterol embolic disease].

Cholesterol arterial embolization is a systemic disease resulting from cholesterol crystal embolization to multiple organs, including the kidney, skin, brain, eye, gastrointestinal tract and extremities. In general, it is associated with high morbidity and mortality, but no optimal treatment has yet been developed. In this paper, we report five patients with cholesterol atheroembolic renal failure. In three of the five patients, combined therapy with corticosteroids and plasma exchange was performed. The three patients survived. On the other hand, the two remaining patients died of multifactorial causes. In this report, the literature on steroid therapy for cholesterol atheroembolic renal disease is reviewed and the efficacy of combined therapy by use of corticosteroids and plasma exchange is evaluated.

Acute Kidney Injury↗

PubMed2000

[A case of Chinese herbs nephropathy in which the progression of renal dysfunction was slowed by steroid therapy].

The patients was a 43-year-old woman whose chief complaints were nausea and heaviness of the heads. There was a history of toxemia of pregnancy. The patient had previously taken Tenshin Tokishigyaku-ka-goshuyu-shokyo-to for two years because of cold sensitivity. Fever, thirst, and loss of appetite developed from approximately 18 months after she started treatment with the Chinese herbal preparation, and she presented at our outpatient clinic 2.5 years later. On initial examination, deterioration of renal function was evident and the serum creatinine level was 3.4 mg/dl. A renal biopsy specimen showed marked interstitial fibrosis without inflammatory cell infiltration, leading to the diagnosis of Chinese herbs nephropathy (CHN). Steroid therapy was started on the 36th hospital day after a sharp rise in the serum creatinine level to 5.1 mg/dl. This resulted in the rapid improvement of renal function and reduction of the serum creatinine to 2.6 mg/dl by 8 weeks after the initiation of treatment. In a study on the use of steroids for patients with progressive moderate renal dysfunction caused by Chinese herbs, Vanherweghem et al. reported that the progression of renal failure was appreciably slowed in patients given steroids when compared with the control group. We were also able to slow the progression of renal dysfunction in our patient by steroid therapy, although the prognosis of CHN is generally considered to be very poor.

Adult↗

PubMed2000

[Non-cholinergic projections from basal forebrain to medial limbic cortex of rat].

Laminar distribution and synaptic organization of non-cholinergic projections to the medial limbic cortex from the basal forebrain (BF) were studied in rats. To eliminate BF cholinergic neurons selectively, a immunotoxin, 192IgG-saporin, was injected into lateral ventricle, and 7 days later, to label the remaining non-cholinergic elements, Phaseolus vulgaris-leucoagglutinin (PHA-L) was injected into BF. In rats injected with the toxin, PHA-L labeled fibers, presumably originating from the remaining non-cholinergic neurons, were distributed in layers V-VI of the medial limbic cortex. Ultrastructural observation showed that the PHA-L labeled fibers were classified into two categories. One class of the axons provided with numerous passant boutons, whereas the other carried fewer passant varicosities. Both classes of terminals were found to make symmetrical synaptic contacts predominantly with dendritic shafts, together with a large number of degenerating terminals making asymmetrical synapses with dendritic spines, presumably cholinergic in nature. These results suggest that non-cholinergic projections from the BF exert a modulatory effect directly on cortical neurons in the medial limbic cortex.

Animals↗

PubMed2000

Adenosine and selective A(2A) receptor agonists reduce ischemia/reperfusion injury of rat liver mainly by inhibiting leukocyte activation.

To examine whether adenosine reduces ischemia/reperfusion (I/R)-induced liver injury by inhibiting leukocyte activation via A(2) receptor (A(2)R) stimulation, we investigated the effects of adenosine and selective A(2A) receptor (A(2A)R) agonists (YT-146 and CGS21680C) on I/R-induced liver injury in rats. Adenosine, YT-146, and CGS21680C, in the concentration of 10(-7) to 10(-5) M, significantly inhibited neutrophil elastase release by about 30 to 40% and increased intracellular Ca(2+) concentrations in isolated neutrophils stimulated with formyl-methionyl-leucyl-phenylalanine (fMLP) in vitro. Adenosine, YT-146, and CGS21680C, in the concentration of 10(-7) to 10(-5) M, significantly inhibited tumor necrosis factor (TNF)-alpha production by monocytes stimulated with endotoxin by about 50%. Although ZM241385, a selective A(2A)R antagonist, significantly enhanced the increase in neutrophil elastase release and intracellular Ca(2+) concentrations in neutrophils stimulated with fMLP, this agent did not affect the endotoxin-induced TNF-alpha production by monocytes. Rats were subjected to liver ischemia for 60 min. Serum levels of transaminases increased after hepatic I/R, peaking at 12 h after reperfusion. The i.v. infusion of adenosine (1 and 10 mg/kg/h), YT-146 (0.1 and 1 mg/kg/h), and CGS21680C (0.1 and 1 mg/kg/h) significantly inhibited the I/R-induced increase in serum transaminase levels 12 h after reperfusion. The I/R-induced decrease in hepatic tissue blood flow was significantly prevented by adenosine and YT-146. Hepatic levels of TNF-alpha, cytokine-induced neutrophil chemoattractant (equivalent to human interleukin-8), and myeloperoxidase were significantly increased after I/R. These increases were significantly inhibited by the administration of adenosine, YT-146, and CGS21680C. Although the histological neutrophil accumulation in the liver was significantly increased after I/R as evaluated by the naphthol AS-D chloroacetate technique, the administration of adenosine, YT-146, and CGS21680C significantly inhibited this increase. These findings suggest that adenosine reduces I/R-induced liver injury both by inhibiting the synthesis of inflammatory mediators and by inhibiting neutrophil degranulation directly, probably through A(2A)R stimulation.

Adenosine↗

PubMed2000

[A case report of chronic myelocytic leukemia with multiple brain metastases, which responded to the gamma-knife therapy].

We report a 78-year-old woman who had multiple leukemic cell tumors in the brain in the course of chronic myelocytic leukemia (CML). As far as we could survey, such brain tumors were extremely rare. She had been followed because of chronic phase of CML until October, 1998, when she noticed muscle weakness in her left upper and lower extremity. A head MRI revealed multiple masses in the brain, a biopsy of which revealed a tumor of CML cells. Although 40 Gy gamma-knife therapy had reduced the size and numbers of brain tumors, we found recurrence of left hemiparesis and tumors three months after the gamma-knife therapy. Whole brain irradiation therapy (total 30 Gy) was somewhat effective to the tumor and hemiparesis transiently subsided. Thereafter her general condition worsened again, and she died in June, 1999, eight months after the diagnosis of the brain tumors of leukemic cells. We had not seen any other clinical evidence of generalized blastic crisis in this patient. In our case, MRI of the brain showed two patterns of metastases, tumor forming and cortical invasive type. We thought that these two patterns of brain involvement might show different responses to the radiation therapy, and it was characteristic in this patient.

Aged↗

PubMed2000

An integrated analysis and database system for full-length cDNA.

Annotation and database system of full-length cDNA sequences was developed. As the components of the system, ORF annotation system, functional annotation system based on database search results, mapping annotation system, and integrated retrieval and display system were developed. In the ORF annotation system integrated analyses using conventional tools are performed and useful retrieval interface using motif list are introduced. In the functional annotation system based on database search results, a new method that characterizes a given unknown cDNA was developed by using a profile of similarity level over words appearing in sequence database entries. In the mapping annotation system, we linked by similarity searches full-length cDNA sequences with database DNA sequences that are already mapped on chromosomes. By using these links, full-length cDNAs can be retrieved by the retrieval condition of physical mapping information. Genetic disease information mapped on the physical mapping site can also be displayed by this system. Furthermore, we constructed an integrated database system for these analyzed data, and thus enabled annotation and selection of full-length cDNAs from points of both gene function and mapping information.

Chromosome Mapping↗

PubMed1999

Substitution of amino acid residue in influenza A virus hemagglutinin affects recognition of sialyl-oligosaccharides containing N-glycolylneuraminic acid.

Sialic acids are essential components of cell surface receptors used by influenza viruses. To determine the molecular mechanisms of viral recognition of two major species of sialic acids, N-acetylneuraminic acid (Neu5Ac) and N-glycolylneuraminic acid (Neu5Gc), we tested the binding reactivity of nine human H3 influenza A viruses to sialylglycolipids containing type II sugar chain and different molecular species of terminal sialic acids. All human H3 viruses tested except A/Memphis/1/71 bound both Neu5Ac and Neu5Gc. Nucleotide sequence analysis suggests that amino acids at 143, 155, and 158 are linked to the viral recognition of Neu5Gc.

Amino Acid Sequence↗

PubMed1999

Effect of chromogranin A (pancreastatin) fragment on invasion of prostate cancer cells.

We investigated the effect of chromogranin A (pancreastatin) fragment on the invasion of PC-3, DU-145 and LNCaP prostate cancer cells through a reconstituted basement membrane (Matrigel) using a Transwell cell culture chamber assay. Chromogranin A fragment increased the invasive capacity of both PC-3 and DU- 145 cells, whereas it had no significant effect of LNCaP cells. Chromogranin A fragment also increased the haptotactic migration of both PC-3 and DU-145 cells to fibronectin. Furthermore chromogranin A fragment increased the fibrinolytic activities of urokinase-type plasminogen activator (u-PA) in fibrin zymograms of both PC-3 and DU-145 cells and the expression of u-PA mRNA of PC-3 cells. However, the growth of these tumor cells was not affected by chromogranin A fragment at any concentrations used in this study. These results indicate that chromogranin A fragment increased the invasive potential of both PC-3 and DU-145 cells probably through enhancement of cell motility and the production of u-PA.

Cell Division↗

PubMed1999

Angiotensin II type 1A receptor knockout mice display less left ventricular remodeling and improved survival after myocardial infarction.

BACKGROUND: Angiotensin II (Ang II) has been implicated in ventricular remodeling after myocardial infarction (MI), which is an important determinant for prognosis after MI. The aim of this study was to determine whether Ang II type 1A receptor (AT(1A))-mediated Ang II signals are critically involved in the mortality and LV remodeling after MI. METHODS AND RESULTS: We examined survival, cardiac geometry and function, cardiac fibrosis, and gene expression of AT(1A) knockout (KO) mice and wild-type (WT) mice at 1 and 4 weeks after large MI. The survival rate was higher in KO mice than in WT mice at 4 weeks after MI. All WT survivors showed severe heart failure, detected by marked increases in both RV weight and lung weight. LV remodeling, such as the development of LV dilatation, LV dysfunction, and cardiac fibrosis at the noninfarcted area, were comparable in both kinds of mice at 1 week after MI. At 4 weeks after MI, however, WT mice showed more marked remodeling than KO mice. mRNA levels of AT(1) at the noninfarcted area were increased from 1 to 4 weeks after MI only in WT mice, whereas levels of AT(2) were not changed by MI in either kind of mouse. Accompanied by the development of geometric and structural remodeling, expression of fetal-type genes, collagen, and transforming growth factor-beta(1) genes were upregulated and sustained in the noninfarcted area of WT hearts. In contrast, they were rapidly downregulated to basal levels at 4 weeks after MI in that of KO hearts. CONCLUSIONS: These results indicate that AT(1A) signals play a pivotal role in the progression of LV remodeling after MI, resulting in overt heart failure.

Animals↗

PubMed1999

Transgenic and knockout models in renin-angiotensin system.

The renin-angiotensin system, composed of enzymatic and signal-transduction cascades, plays a key role in the regulation of arterial blood pressure and in the development of certain forms of experimental and human hypertension. The products of this system, angiotensin peptides, exert a wide range of physiologically important effects on many tissues, including those of the cardiovascular systems, through their actions on angiotensin receptors. Molecular genetic and transgenic studies have begun to implicate some of the genes encoding components of the renin-angiotensin system in the development of cardiovascular diseases. Recently, we succeeded in generating transgenic mice with chronic hypertension and with inducible hypertension during pregnancy and in creating mice homozygous for a targeted disruption of the angiotensinogen gene (the only known precursor of angiotensins), resulting in the complete loss of angiotensin signals in vivo. Here, we will review recent advances related to the functional analysis of the renin-angiotensin system, in particular by focusing on transgenic approaches including gene targeting.

Animals↗

PubMed1999

Changes with aging of steroidal levels in the cerebrospinal fluid of women.

OBJECTIVE: Age-related changes of steroid levels in the central nervous system (CNS) are not well understood. To investigate whether steroidal conditions in the CNS of women change with aging and menopause, steroid levels have been measured in serum and cerebrospinal fluid (CSF), and examined correlations with aging. METHODS: Serum and CSF concentrations of estradiol (E2), cortisol, dehydroepiandrosterone (DHEA), DHEA sulfate (DHEAS) and albumin were measured in 80 female patients who underwent operations for benign gynecological diseases. They had no endocrinological or neurological disorders and were aged 17-71 years; 62 patients were in premenopause and 18 were in postmenopause. RESULTS: Serum levels of E2 decreased markedly after menopause, while levels of DHEA and DHEAS decreased gradually with age. There was no significant change with age of serum cortisol levels. The CSF concentrations of E2 (0.2-3 pg/ml) decreased with age [correlation coefficient (r)= 0.31, P < 0.01]. The CSF DHEA levels (0.1-0.8 ng/ml) did not change with age although not significantly, but CSF cortisol levels (0.1-0.6 microg/dl) increased with age (r = 0.35, P < 0.01). The CSF DHEAS concentrations were below the sensitivity of the radioimmunoassay (RIA) (1 ng/ml). The CSF/serum ratios of cortisol increased with age (r = 0.30, P < 0.01), as did those of DHEA (r = 0.55, P < 0.01). Although serum albumin levels did not change throughout life, CSF albumin levels and CSF/serum albumin ratios increased gradually with age (r = 0.28, P = 0.052; r = 0.23, P = 0.114, respectively), but there was no significance. There were marked decreases of serum E2 and DHEA levels and CSF E2 levels in postmenopausal women (P < 0.05), but CSF cortisol levels increased (P < 0.05) and DHEA levels in CSF were maintained after menopause. CONCLUSION: These results indicate that steroids in CSF become cortisol dominated and deficient in estrogens with aging, especially after menopause.

Adolescent↗

PubMed1999

Molecular cloning and expression of human neurochondrin-1 and -2.

Human neurochondrins have been cloned from a brain cDNA library. The human neurochondrin-1 and -2 predict leucine-rich (15.8 and 15.9%) proteins of 729 and 712 amino acid residues, with molecular weights of 78.9 and 77.2 kDa, respectively. The deduced amino acid sequence indicates 98% identity among human, mouse and rat species. Northern analysis indicates that about 4 kb human neurochondrin mRNAs are abundant in the fetal and the adult brain.

Amino Acid Sequence↗

PubMed1999

Human endothelial cells augment early CD40 ligand expression in activated CD4+ T cells through LFA-3-mediated stabilization of mRNA.

Human endothelial cells (EC) augment CD40 ligand (CD40L) expression on PHA-activated CD4+ T cells at early times (e.g., 4-6 h). Fixed EC, devoid of mRNA, are comparable to living EC in their capacity to augment early CD40L expression on CD4+ T cells. Fixed EC increase T cell mRNA expression of both IL-2 and CD40L compared with PHA alone at 6 h. EC are unable to increase the rate of transcription of CD40L compared with PHA alone as measured with a promoter-reporter gene, although they do increase transcription of an IL-2 promoter-reporter gene. Fixed EC prolong the half-life of CD40L mRNA >2-fold. Inclusion of anti-human LFA-3 (CD58) mAb or pretreatment of EC with an LFA-3 antisense oligonucleotide blocks EC-induced increases in CD40L expression, whereas mAb to ICAM-1 or pretreatment with ICAM-1 antisense oligonucleotide does not. Moreover, mAb to LFA-3 reverses the capacity of EC to prolong the half-life of CD40L mRNA, whereas mAb to ICAM-1, even in combination with mAb to ICAM-2, does not. We conclude that EC use LFA-3 to increase early CD40L protein expression on newly activated CD4+ T cells by stabilizing CD40L mRNA.

Adjuvants, Immunologic↗

PubMed1999

Evidence for direct binding of fatty acids and eicosanoids to human peroxisome proliferators-activated receptor alpha.

The alpha isoform of peroxisome proliferators-activated receptor (PPAR) is activated by fatty acids, their metabolites, and the fibrate class of lipid-lowering agents. To test the ability of these activators to directly bind the ligand-binding domain of human PPARalpha, we performed a competitive binding assay using radiolabeled [(3)H]KRP-297, a known ligand for human PPARalpha. Long-chain fatty acids and eicosanoids were even more potent ligands for human PPARalpha than the hitherto most potent PPARalpha ligand WY-14,643. Moreover, these natural ligands avidly activated this receptor in a transient transcriptional assay. This study provides the direct evidence that human PPARalpha is activated through the direct binding of fatty acids and eicosanoids, as well as of a fibrate, to its ligand-binding domain.

Animals↗

PubMed1999

Targeted expression of human CuZn superoxide dismutase gene in mouse central nervous system.

Copper zinc superoxide dismutase (CuZnSOD) is an important enzyme for the detoxification of reactive oxygen species. Particularly in the central nervous system (CNS), reactive oxygen species are often associated with acute brain injuries and chronic neurodegeneration. It has been demonstrated in vivo that there is an inverse correlation between CuZnSOD activity and neuronal death after acute brain injury. To further understand the protective role of CuZnSOD upon neurons, we have generated transgenic mouse lines with targeted expression of the human CuZnSOD gene (SOD1) that is driven by a rat neuron-specific enolase gene promoter in neurons of the CNS. The transgenic SOD1 expression was restricted to the CNS identified by reverse transcriptase polymerase chain reaction and SOD gel electrophoresis assays. The CuZnSOD activity was significantly increased in the brain stem of the transgenic mice. Immunostaining of human CuZnSOD activity showed that Purkinje cells in the cerebellar cortex were the most intensely stained neurons in the CNS of the transgenic mice.

Animals↗