Biomedical subjects

M Takemura

Publications and source records attributed to M Takemura.

At least 73 records · Page 4Linked to original sources

PubMed2000

Primary volvulus of the small intestine in an adult, and review of 15 other cases from the Japanese literature.

We report case of primary volvulus of the small intestine and review 15 cases from the Japanese literature. A 56-year-old woman, with a history of appendectomy 30 years previously, was admitted with abdominal distension and signs of peritonitis. Abdominal computed tomography (CT) demonstrated a whirl-like pattern of the mesentery, showing the tightly twisted mesentery around the point of torsion. An emergency laparotomy revealed strangulation of the small intestine, from 200 cm anal to the Treitz ligament to 5 cm oral to the terminal ileum, caused by 360 degrees clockwise torsion. There was no adhesion caused by the previous operation nor were there any congenital anomalies. The strangulated intestine was removed and jejunocolonostomy was performed. The patient was discharged from hospital on day 39 after the operation. Primary volvulus of the small intestine was reported to be rare in Japan, but the mortality was 26%. Immediate diagnosis and surgical intervention is essential to achieve a good outcome. A whirl-like pattern of the mesentery is a typical sign of this condition on CT.

Female↗

PubMed2000

Mapping of c-Fos in the trigeminal sensory nucleus following high- and low-intensity afferent stimulation in the rat.

Although previous studies have suggested that nociceptive afferents from intra-oral and facial structures are organized differently in the trigeminal sensory nucleus (TSN), more detailed data are needed. The present study aimed to fill this gap, by examining the changes in the expression of c-Fos within the rat TSN following high- and low-intensity electrical stimulation applied to the Gasserian ganglion (GG). A low-intensity stimulus (0.1 mA) induced c-Fos in many neurons in the dorsomedial subdivision (Vodm) of the oral subnucleus (Vo; mean +/- SEM in a certain segment = 163.0 +/- 42.7), in the medial part of the dorsomedial subdivision (Vidm) of the interpolar subnucleus (Vi; 120.5 +/- 40.1), in the medial corner of the magnocellular zone (VcIII/IV; 47.5 +/- 10.5), and in the superficial layers (VcI/II; 1330.0 +/- 65.6) along the entire length of the dorsomedial-ventrolateral axis of the caudal subnucleus (Vc). A modest number of Fos-positive neurons were induced in the dorsal principal subnucleus (Vp; 10.0 +/- 4.9) and in the lateral VcIII/IV (11.5 +/- 1.6). A high-intensity stimulus (1.0 mA) significantly increased the number of Fos-positive neurons in each subdivision compared with the low-intensity stimulus (Vp 32.3 +/- 10.8; Vodm 270.3 +/- 75.3; Vidm 189.3 +/- 38.5; medial VcIII/IV 77.5 +/- 18.2; lateral VcIII/IV 24.8 +/- 9.3; VcI/II, 2155.8 +/- 470.2). At both low- and high-intensity stimulation, the fields where Fos-positive neurons appeared are restricted to the dorsal or dorsomedial subdivisions of the rostral subnuclei, Vp, Vo and Vi, where the main projectional fields of primary afferents from the intraoral structures are found, while Fos-positive neurons were distributed in the entire VcI/II, along the dorsomedial-ventrolateral axis of Vc, where the main projectional fields of primary afferents from the facial skin are found. The threshold to induce c-Fos is, however, different according to the fields. These results suggest that nociceptive processing in the intra-oral region is mediated through the entire length of the rostro-caudal axis of TSN, but is mediated primarily through VcI/II in the facial region.

Afferent Pathways↗

PubMed2000

GABA(A) receptor-mediated effects on expression of c-Fos in rat trigeminal nucleus following high- and low-intensity afferent stimulation.

We examined the effects of systemic administration of a GABA(A) receptor agonist, muscimol, or antagonist, bicuculline, on the expression of c-Fos protein induced 3h after electrical stimulation of the trigeminal ganglion at low (0.1 mA) or high intensities (1. 0 mA) in the urethane-anesthetized rat. In saline-treated rats, 10 min stimulation of the trigeminal ganglion induced c-Fos-immunopositive neurons throughout the full extent of the ipsilateral superficial layers of the trigeminal nucleus caudalis, and dorsal or dorsomedial part of the nuclei rostral to obex (trigeminal nucleus principalis, dorsomedial nucleus of trigeminal nucleus oralis, dorsomedial nucleus of trigeminal nucleus interpolaris). Animals stimulated at 1. 0 mA induced a significantly higher number of labeled neurons in all trigeminal sensory nucleus than animals stimulated at 0.1 mA. In rats treated with 1mg/kg i.p. muscimol and stimulated at 0.1 mA, the numbers of Fos-positive neurons in trigeminal nucleus caudalis, dorsomedial nucleus of trigeminal nucleus interpolaris, and dorsomedial nucleus of trigeminal nucleus oralis were significantly decreased. However, after stimulation at 1.0 mA, the numbers of Fos-positive neurons in the superficial layers of trigeminal nucleus caudalis was increased and no changes occurred in the numbers of Fos-positive neurons in the magnocellular zone of trigeminal nucleus caudalis, the dorsomedial nucleus of trigeminal nucleus interpolaris, or dorsomedial nucleus of trigeminal nucleus oralis compared to saline-treated controls. In rats treated with 2mg/kg i.p. bicuculline and stimulated at 0.1 mA, the number of Fos-positive neurons increased in the superficial layers of trigeminal nucleus caudalis and trigeminal nucleus principalis. However, after stimulation at 1.0 mA, the number of Fos-positive neurons was unchanged in superficial layers of trigeminal nucleus caudalis, but decreased in the magnocellular zone of trigeminal nucleus caudalis, dorsomedial nucleus of trigeminal nucleus interpolaris and dorsomedial nucleus of trigeminal nucleus oralis. There was a specific loss of Fos-positive neurons in the maxillary and ophthalmic divisions (ventrolateral half) of trigeminal nucleus caudalis. These results indicate that the expression of c-Fos in the trigeminal nucleus is differentially regulated through GABA(A) receptors in a manner that is dependent on the nucleus and the type of primary afferents that are activated by different stimulus intensities.

Afferent Pathways↗

PubMed2000

Reduced IFNgamma production in response to IL-12 stimulation and/or reduced IL-12 production in atopic patients.

BACKGROUND: Several studies have shown that interleukin (IL)-4 and interferon-gamma (IFNgamma) are important for the regulation of IgE production and that IL-12 induces IFNgamma. OBJECTIVE: IFNgamma production in response to IL-12 stimulation and IL-12 production were investigated in peripheral blood mononuclear cells (PBMCs) of atopic patients with various levels of serum IgE. METHODS: Cytokine production from PBMCs was measured following stimulation with a nonspecific stimulator (phytohemagglutinin: PHA), a specific stimulator (Der f 1) and IL-12 in 17 healthy controls and 23 atopic patients with various serum IgE levels. RESULTS: The IFNgamma production by IL-12-stimulated PBMCs in the atopic group was lower than that in the control group. Furthermore, the serum IgE level was negatively correlated with IFNgamma production by PBMCs stimulated with IL-12 (P < 0.001), and with IL-12 production by PBMCs stimulated with Der f 1 (P < 0.001). Although the IFNgamma concentrations by PHA-stimulated PBMCs were correlated with those by IL-12-stimulated PBMCs, there were differences in several patients. CONCLUSIONS: Our results indicated that atopic patients may have some abnormality in the IL-12-IFNgamma loop. It was shown that the elevation in IgE levels in atopic patients may be due to reduced IFNgamma production in response to IL-12 stimulation and/or due to reduced IL-12 production.

Adolescent↗

PubMed2000

Suppression of neurocognitive damage in LP-BM5-infected mice with a targeted deletion of the TNF-alpha gene.

Brain levels of TNF-alpha increase in many inflammatory conditions, including HIV-1 infection, and may contribute to neurodegenerative processes. The paucity of agents that can selectively and potently block TNF-alpha processing or its receptors has led us to investigate the role of TNF-alpha in chronic neurodegeneration associated with retroviral infection using mice with targeted deletions of the TNF-alpha gene. Infection of wild-type C57BL/6 mice with the LP-BM5 murine leukemia retrovirus mixture leads to the development of a severe immunodeficiency as well as cognitive deficits and neuronal damage. TNF-alpha-(-/-) mice infected with LP-BM5 developed a systemic immunopathology indistinguishable in severity from that observed in contemporaneously infected wild-type mice. In contrast, the performance of infected TNF-alpha-(-/-) mice in the Y-maze and Morris water maze was not different from that of uninfected TNF-alpha-(-/-) mice. The extent of glial activation in the striatum, as indicated by the increase in density of peripheral benzodiazepine receptors, was equivalent in both groups of LP-BM5-infected mice. However, the decrease in striatal MAP-2 expression, a marker of neurodegeneration observed in infected wild-type mice, was not found in infected TNF-alpha-(-/-) mice. While the loss of TNF-alpha appeared to have no effect on the course or severity of the central or peripheral immunopathology resulting from LP-BM5 infection, the behavioral and biochemical manifestations were substantially curtailed in the TNF-alpha-(-/-) mice. These findings directly support a role for TNF-alpha in the neurodegenerative processes associated with viral infections such as HIV-1.

Animals↗

PubMed2000

Antimycobacterial activities of novel levofloxacin analogues.

In order to investigate structure-activity relationships between antimycobacterial activities and basic substituents at the C-10 position of levofloxacin (LVFX), we synthesized a series of pyridobenzoxazine derivatives by replacement of the N-methylpiperazinyl group of LVFX with various basic substituents. A compound with a 3-aminopyrrolidinyl group had one-half the activity of LVFX against Mycobacterium avium, M. intracellulare, and M. tuberculosis. Mono- and dimethylation of the 3-amino moiety of the pyrrolidinyl group increased the activities against M. avium and M. intracellulare but not those against M. tuberculosis. On the other hand, dialkylation at the C-4 position of the 3-aminopyrrolidinyl group enhanced the activities against M. avium, M. intracellulare, and M. tuberculosis. Thus, introduction of an N-alkyl or a C-alkyl group(s) into the 3-aminopyrrolidinyl group may contribute to an increase in potency against M. avium, M. intracellulare, and/or M. tuberculosis, probably through elevation of the lipophilicity. However, among the compounds synthesized, compound VII, which was a 2,8-diazabicyclo[4.3.0]nonanyl derivative with relatively low lipophilicity, showed the most potent activity against mycobacterial species: the activity was 4- to 32-fold more potent than that of LVFX and two to four times as potent as that of gatifloxacin. These results suggested that an increase in the lipophilicity of LVFX analogues in part contributed to enhancement of antimycobacterial activities but that lipophilicity of the compound was not a critical factor affecting the potency.

Anti-Infective Agents↗

PubMed2000

Saccharomyces cerevisiae sigma 1278b has novel genes of the N-acetyltransferase gene superfamily required for L-proline analogue resistance.

We discovered on the chromosome of Saccharomyces cerevisiae Sigma 1278b novel genes involved in L-proline analogue L-azetidine-2-carboxylic acid resistance which are not present in the standard laboratory strains. The 5.4 kb-DNA fragment was cloned from the genomic library of the L-azetidine-2-carboxylic acid-resistant mutant derived from a cross between S. cerevisiae strains S288C and Sigma 1278b. The nucleotide sequence of a 4.5-kb segment exhibited no identity with the sequence in the genome project involving strain S288C. Deletion analysis indicated that one open reading frame encoding a predicted protein of 229 amino acids is indispensable for L-azetidine-2-carboxylic acid resistance. The protein sequence was found to be a member of the N-acetyltransferase superfamily. Genomic Southern analysis and gene disruption showed that two copies of the novel gene with one amino acid change at position 85 required for L-azetidine-2-carboxylic acid resistance were present on chromosomes X and XIV of Sigma 1278b background strains. When this novel MPR1 or MPR2 gene (sigma 1278b gene for L-proline analogue resistance) was introduced into the other S. cerevisiae strains, all of the recombinants were resistant to L-azetidine-2-carboxylic acid, indicating that both MPR1 and MPR2 are expressed and have a global function in S. cerevisiae.

Amino Acid Sequence↗

PubMed2000

Mechanism of increases in L-kynurenine and quinolinic acid in renal insufficiency.

Marked increases in metabolites of the L-tryptophan-kynurenine pathway, L-kynurenine and quinolinic acid (Quin), were observed in serum and cerebrospinal fluid (CSF) of both the rat and human with renal insufficiency. The mechanisms responsible for their accumulation after renal insufficiency were investigated. In patients with chronic renal insufficiency, elevated levels of serum L-kynurenine and Quin were reduced by hemodialysis. In renal-insufficient rats, Quin and L-kynurenine levels in serum, brain, and CSF were also increased parallel to the severity of renal insufficiency. Urinary excretion of Quin (3.5-fold) and L-kynurenine (2.8-fold) was also increased. Liver L-tryptophan 2,3-dioxygenase activity (TDO), a rate-limiting enzyme of the kynurenine pathway, was increased in proportion to blood urea nitrogen and creatinine levels. Kynurenine 3-hydroxylase and quinolinic acid phosphoribosyltransferase were unchanged, but the activities of kynureninase, 3-hydroxyanthranilate dioxygenase, and aminocarboxymuconate-semialdehyde decarboxylase (ACMSDase) were significantly decreased. Systemic administrations of pyrazinamide (ACMSDase inhibitor) increased serum Quin concentrations in control rats, demonstrating that changes in body ACMSDase activities in response to renal insufficiency are important factors for the determination of serum Quin concentrations. We hypothesize the following ideas: that increased serum L-kynurenine concentrations are mainly due to the increased TDO and decreased kynureninase activities in the liver and increased serum Quin concentrations are due to the decreased ACMSDase activities in the body after renal insufficiency. The accumulation of CSF L-kynurenine is caused by the entry of increased serum L-kynurenine, and the accumulation of CSF Quin is secondary to Quin from plasma and/or Quin precursor into the brain.

Adult↗

PubMed2000

Studies on 8-methoxyquinolones: synthesis and antibacterial activity of 7-(3-amino-4-substituted)pyrrolidinyl derivatives.

A series of 8-methoxyquinolones bearing 3-amino-4-methylpyrrolidines or 3-amino-4-fluoromethylpyrrolidines at the C-7 position was synthesized and their physicochemical and biological properties were evaluated. All of the compounds synthesized showed more potent activity than LVFX (3) against both gram-positive and negative bacteria. Increases in lipophilicity of these compounds had desirable effects on their potency of single intravenous toxicity and pharmacokinetic profiles in animals. Among the compounds synthesized, 1-fluorocyclopropyl derivatives 17 and 20, and 7-(cis-3-amino-4-fluoromethylpyrrolidinyl) derivative 19 (DC-756h) showed negative responses in the micronucleus test in mice while 1-cyclopropyl-7-(3-aminopyrrolidinyl) derivative 16 showed a positive response. These results suggested that the introduction of a fluorine atom into the 3-aminopyrrolidinyl substituent resulted in favorable influence on genetic toxicity as well as into the N-1 cyclopropyl substituent.

Animals↗

PubMed2000

Characterization of a novel gene encoding a putative single zinc-finger protein, ZIM, expressed during the reproductive phase in Arabidopsis thaliana.

By differential screening of an arrayed normalized cDNA library from the inflorescence apex in Arabidopsis, a cDNA clone having a deduced amino acid sequence with a motif for a zinc finger was isolated as one of the genes expressed specifically in the reproductive phase. The deduced protein has a modular structure with a putative single C2-C2 zinc-finger motif distantly related to a GATA-1-type finger, a basic region with a sequence resembling a nuclear localization signal, and an acidic region. The gene seemed to have been formed by the exon-shuffling during its molecular evolution, since individual domains are encoded by discrete exons. RNA gel blot analysis showed its expression in shoot apex and flowers in the reproductive phase. The gene was named ZIM for Zinc-finger protein expressed in Inflorescence Meristem. The nuclear localization of ZIM was detected using GFP as a reporter. These results suggest that ZIM is a putative transcription factor involved in inflorescence and flower development.

Amino Acid Sequence↗

PubMed2000

Systematic isolation of highly transcribed genes in inflorescence apices in Arabidopsis thaliana from an equalized cDNA library.

To analyze plant meristem functions, we systematically isolated thirteen cDNA clones for transcripts that are highly expressed in the inflorescence apices of Arabidopsis by differential screening, using an equalized cDNA library with the clones arrayed on membranes. Their deduced amino acid sequences indicate important functions for proteins in determining the cell wall architecture, translation capacity and mitotic activity in the shoot apex during reproductive growth.

Arabidopsis↗

PubMed2000

Isolation and identification of the probing stimulants in the rice plant for the white-back planthopper, Sogatella furcifera (homoptera: delphacidae).

Adult females of the white-back planthopper, Sogatella furcifera, showed characteristic behavior of stylet sheath deposit on a parafilm membrane when fed on a 2% aqueous crude rice leaf and stem extract containing 15% sucrose. Subsequent bioassays revealed that the butanol-soluble fraction of the extract was highly active against the insects. When the butanol fraction was chromatographed on an ODS open column and eluted in sequence with a mixture of an increasing concentration of methanol in water, the 40 % methanol fraction was separated as the most active. A further bioassay of the HPLC components in the active fraction revealed that two major components (1 and 3) stimulated the high probing activity of the white-back planthopper only when they were combined. Of the active components, one component (3) was identified to be tricin 5-O-glucoside by spectroscopic analyses.

Animals↗

PubMed2000

[Clinical significance of ambulatory intraesophageal bilirubin monitoring in diagnosis of gastroesophageal reflux].

To evaluate the usefulness of ambulatory intraesophageal bilirubin monitoring in the diagnosis of GER, 38 patients with reflux symptoms and 7 controls were studied, using Bilitec 2000. The % time of bilirubin and acid reflux was less than 5% in all of the controls. In 3 patients of NUD, % time of acid reflux was less than 5%, but that of bilirubin was more than 8% in 2 patients. Acid reflux was found only in 1 of 4 patients who had a history of subtotal gastrectomy, but abnormal bilirubin reflux was found in all of 4 patients. In the other 31 patients, a significant difference was found in the % time of bilirubin reflux by the severity of reflux esophagitis, whereas this difference was not found in that of acid reflux. Intraesophageal bilirubin monitoring is useful in the diagnosis of GER and is essential in patients with hypochlorhydria or minimal reflux.

Adult↗

PubMed2000

Thoracic esophageal cancer recurred later than 2 years after esophagectomy with extended lymphadenectomy.

PURPOSE: Although the majority of recurrence was found in 2 years after esophagectomy, esophageal cancer could recur lately. To find efficient follow up, the patients were compared by periods of recurrence detected. SUBJECTS AND METHODS: Esophagectomized 227 patients were subjected. Median follow up period was 1289 days. The disease recurred in 84 patients (Group A) in 2 years after surgery and in 17 (Group B) lately. Clinicopathological factors were compared between these 2 groups. RESULTS: There was no difference in background and clinicopathological factors, except Group A was at significantly advanced stage than B. The most common pattern of recurrence was hematogeneous in Group A, whereas lymphatic in Group B, which was significantly different. In Group B, survival rate of patients detected by lymphatic recurrence, which responded to radiation, was higher than that detected by hematogeneous one. CONCLUSION: To prolong survival, the patients should be carefully followed up later than 2 years after surgery with regard for lymphatic recurrence.

Aged↗

PubMed1999

Systematic isolation of genes expressed at low levels in inflorescence apices of Arabidopsis thaliana.

We constructed an equalized cDNA library from Arabidopsis inflorescence shoot apices including inflorescence meristem, floral meristem and flower tissue collected before stage 5 of flower development. The cDNA clones were arrayed on membranes and were differentially screened using cDNA pools from vegetative and inflorescence tissues as probes. Each clone was classified by expression specificity and expression level. By removing the clones that displayed hybridization signals, 384 out of 3264 clones in this library remained as candidates for inflorescence-specific mRNAs expressed at low levels. Sequence analysis of all selected clones indicated that 53 were identical and 120 were homologous to genes in public protein databases. The remaining 211 selected clones had no significant amino acid sequence similarities with those deduced from any reported genes, though 62 of them appeared in Arabidopsis expressed sequenced tags (ESTs). About 40% of the selected clones were novel, validating the present approach for gene discovery. Northern blot analysis of 22 randomly selected clones confirmed that most were expressed preferentially in inflorescence tissues. In addition, many clones were transcribed at relatively low levels. We demonstrate that the screening method of the present study is useful for systematic classification of cDNA species based on expression specificity.

Animals↗

PubMed1999

BQ788, an endothelin ET(B) receptor antagonist, attenuates stab wound injury-induced reactive astrocytes in rat brain.

Endothelins (ETs) are suggested to be involved in pathological or pathophysiological responses on brain injuries. In the present study, an involvement of ETs on activation of astrocytes in vivo was examined by using selective endothelin receptor antagonists. A stab wound injury on rat cerebral cortex increased immunoreactive ET-1 at the injured site. GFAP-positive [GFAP(+)] and vimentin-positive [Vim(+)] cells appeared at the injured site in 1 day to 2 weeks after the injury. A continuous infusion of BQ788, a selective ETB receptor antagonist, into cerebral ventricle (23 nmole/day) attenuated increase in the numbers of GFAP(+) and Vim(+) cells after the injury. FR139317, a selective ETA antagonist (23 nmole/day), slightly decreased the number of Vim(+) cells but not that of GFAP(+) cells. Increase in the number of microglia/macrophages by a stab wound injury, which was determined by Griffonia simplicifolia isolectin B4 staining, was not affected by BQ788 and FR139317. These results suggest that activation of glial ETB receptors is one of the signal cascades leading to reactive astrocytes on brain injuries.

Animals↗

PubMed1999

L-tryptophan-kynurenine pathway metabolite 3-hydroxyanthranilic acid induces apoptosis in macrophage-derived cells under pathophysiological conditions.

Accumulation of L-kynurenine and 3-hydroxyanthranilic acid (3HAA) occurs in the monocyte-derived cells following immune stimulation, and may derive from L-tryptophan following induction of indoleamine-2,3-dioxygenase. In the present study, we evaluate the possibility that 3HAA acts as an endogenous inducer of monocyte/macrophage apoptosis. Supplementation with 200 microM of 3HAA, but not other L-tryptophan metabolites tested, significantly increased the number of apoptotic cells in both THP-1 and U937 cells. Catalase, superoxide dismutase and manganese ions markedly enhanced apoptosis in the presence of 3HAA in these cells. The present results suggest that 3HAA induces the macrophage/monocyte apoptosis under certain conditions, which may be relevant to pathophysiology of inflammatory conditions.

3-Hydroxyanthranilic Acid↗

PubMed1999

Inhibitory effects of beer and other alcoholic beverages on mutagenesis and DNA adduct formation induced by several carcinogens.

The possibility that beer and other alcoholic beverages could be antimutagenic against the heterocyclic amines (HAs), a group of carcinogens produced on cooking proteinaceous foods, has been explored. In the Salmonella mutation assays, beer showed inhibitory effects against several HAs [preactivated Trp-P-1, Trp-P-2(NHOH), and Glu-P-1(NHOH)] that are directly mutagenic in bacteria. Japanese sake, red and white wines, and brandy were also effective. However, ethyl alcohol alone did not show these effects. The formation of O(6)-methylguanine by N-methyl-N'-nitro-N-nitrosoguanidine in the DNA of Salmonella YG7108 was also inhibited by beer. Nonvolatile beer components were administered orally to CDF(1) mice together with Trp-P-2. Adducts in the liver DNA were significantly decreased by the beer, as compared to those in controls fed Trp-P-2 only. Although several phenolic compounds known to be present in beer were antimutagenic toward these mutagens, their effects were very small. It was concluded that some yet to be identified component(s) of beer is (are) responsible for this antimutagenicity.

Alcoholic Beverages↗