Biomedical subjects

Y Sekiguchi

Publications and source records attributed to Y Sekiguchi.

At least 19 recordsLinked to original sources

PubMed2000

Analysis of condensed phosphates in food products by ion chromatography with an on-line hydroxide eluent generator.

An ion chromatographic method with gradient elution using an automated eluent generator was developed for the simultaneous determination of condensed phosphates (CPs) such as orthophosphate (P1), pyrophosphate (P2), polyphosphate, trimetaphosphate and phytate in food products. The linear calibration curves for P1, P2, tripolyphosphate, and tetrapolyphosphate in the range 0.5-500 microM had a correlation factor of 0.999 or better. The precision of the method for the CP peak areas obtained with the hydroxide eluent generator was better than that obtained with potassium hydroxide eluents prepared off-line. This method was applied to the determination of CPs in food products such as ham, fish paste, and cheese extracted by trichloroacetic acid.

Chromatography, Liquid↗

PubMed2000

Sensory innervation of the lumbar dura mater passing through the sympathetic trunk in rats.

STUDY DESIGN: Sensory innervation of the lumbar dura mater passing through the sympathetic trunk was investigated by neuronal tracing and immunohistochemical methods. OBJECTIVE: To assess an anatomic basis indicating that sympathetic block in the higher lumbar region is effective for patients with low back pain. SUMMARY OF BACKGROUND DATA: Low back pain is elicited by disorder or mechanical stimulation of the lumbar dura mater. Clinically, the authors often have observed patients in whom root block at the responsible level or sympathetic block at the higher level could relieve low back pain. Therefore, there may be two different sensory routes, the segmental innervation at the same level and nonsegmental fibers from higher dorsal root ganglia. METHODS: The tracers were injected into the sympathetic trunk between L3 and L4 of rats. The lumbar dorsal root ganglia and dura mater were examined, and labeled cells were measured in size and the distribution. To establish the sensory property, the materials were processed in immunohistochemistry for calcitonin gene-related peptide. RESULTS: Many small- to medium-sized neurons were retrogradely labeled L1 and L2 dorsal root ganglia after injection into the sympathetic trunk. The anterogradely labeled fibers were found in the dura mater at L4 and L5. Some of the labeled neurons and fibers were immunoreactive for calcitonin gene-related peptide. CONCLUSION: Sensory fibers from the upper lumbar ganglia innervated the lower lumbar dura mater directly. These sensory nerves may mediate low back pain and possibly interact with sympathetic nerves.

Animals↗

PubMed2000

Anti-IL-12 antibody prevents the development and progression of multiple sclerosis-like relapsing--remitting demyelinating disease in NOD mice induced with myelin oligodendrocyte glycoprotein peptide.

Treatment with monoclonal anti-IL-12 antibody injected on day 0, 7 and 10 after immunization with myelin oligodendrocyte glycoprotein (MOG) peptide 35-55 in NOD mice resulted in significant suppression of the development and the severity of the chronic relapsing-remitting experimental autoimmune encephalomyelitis (EAE) both clinically and histologically. The spleen cells from anti-IL-12 antibody treated mice displayed markedly inhibited MOG35-55 specific proliferation and IFN-gamma production. MOG35-55 specific antibody production was enhanced by anti-IL-12 antibody treatment. These results suggest that IL-12 is critically involved in the pathogenesis of MOG-induced EAE and that antibody to IL-12 could be an effective therapeutic agent in the clinical treatment of autoimmune demyelinating diseases such as multiple sclerosis (MS).

Animals↗

PubMed2000

Syntrophothermus lipocalidus gen. nov., sp. nov., a novel thermophilic, syntrophic, fatty-acid-oxidizing anaerobe which utilizes isobutyrate.

A new anaerobic, thermophilic, syntrophic, fatty-acid-oxidizing bacterium designated strain TGB-C1T was isolated from granular sludge in a thermophilic upflow anaerobic sludge blanket (UASB) reactor. The cells were slightly curved rods and were weakly motile. Spore formation was not observed. The optimal temperature for growth was around 55 degrees C and growth occurred in the range 45 to 60 degrees C. The pH range for growth was 5.8-7.5, and the optimum pH was 6.5-7.0. Crotonate was the only substrate that allowed the strain to grow in pure culture. However, in co-culture with the thermophilic, hydrogenotrophic Methanobacterium thermoautotrophicum strain delta H, the isolate could syntrophically oxidize saturated fatty acids with 4-10 carbon atoms, including isobutyrate. During the degradation of isobutyrate by the co-culture, isobutyrate was isomerized to butyrate, which was then oxidized. The strain was not able to utilize sulfate, sulfite, thiosulfate, nitrate, fumarate or Fe(III) as electron acceptor. The DNA base composition was 51.0 mol%. 16S rDNA sequence analysis revealed that the strain belongs to the family Syntrophomonadaceae, but it was only distantly related to other known species of beta-oxidizing syntrophs. Hence, the name Syntrophothermus lipocalidus is proposed for TGB-C1T as a new species of a new genus.

Bacterial Typing Techniques↗

PubMed2000

Cultivation and in situ detection of a thermophilic bacterium capable of oxidizing propionate in syntrophic association with hydrogenotrophic methanogens in a thermophilic methanogenic granular sludge.

The thermophilic, anaerobic, propionate-oxidizing bacterial populations present in the methanogenic granular sludge in a thermophilic (55 degrees C) upflow anaerobic sludge blanket reactor were studied by cultivation and in situ hybridization analysis. For isolation of propionate-degrading microbes, primary enrichment was made with propionate as the sole energy source at 55 degrees C. After several attempts to purify the microbes, a thermophilic, syntrophic, propionate-oxidizing bacterium, designated strain SI, was isolated in both pure culture and coculture with Methanobacterium thermoautotrophicum. Under thermophilic (55 degrees C) conditions, strain SI oxidized propionate, ethanol, and lactate in coculture with M. thermoautotrophicum. In pure culture, the isolate was found to ferment pyruvate. 16S ribosomal DNA sequence analysis revealed that the strain was relatively close to members of the genus Desulfotomaculum, but it was only distantly related to any known species. To elucidate the abundance and spatial distribution of organisms of the strain SI type within the sludge granules, a 16S rRNA-targeted oligonucleotide probe specific for strain SI was developed and applied to thin sections of the granules. Fluorescence in situ hybridization combined with confocal laser scanning microscopy revealed that a number of rod-shaped cells were present in the middle and inner layers of the thermophilic granule sections and that they formed close associations with hydrogenotrophic methanogens. They accounted for approximately 1.1% of the total cells in the sludge. These results demonstrated that strain SI was one of the significant populations in the granular sludge and that it was responsible for propionate oxidation in the methanogenic granular sludge in the reactor.

Bacteria↗

PubMed1999

Yeast tom1 mutant exhibits pleiotropic defects in nuclear division, maintenance of nuclear structure and nucleocytoplasmic transport at high temperatures.

A tom1-1 mutant was isolated from Saccharomyces cerevisiae. At high temperatures, 60% of the cells were arrested as dumbbell forms with a single large nucleus containing duplicated DNA and a short spindle. Electron-microscopy showed electron-dense structures scattered within the nucleus. Indirect immunofluorescent microscopy revealed these structures to be fragmented nucleoli since the dotted structures were stained with anti-Nop1(fibrillarin) antibody in large regions of the nuclei. Fluorescent in situ hybridization analysis using oligo(dT) revealed nuclear accumulation of poly(A)+RNA. We cloned TOM1 which encodes a large protein (380kDa) with a hect (homologous to E6-AP C terminus)-domain at its C terminus. Deletions of either this hect-region or the entire gene made cellular growth temperature-sensitive. Site-directed mutagenesis of the conserved cysteine residue (tom1C3235A) in the hect-domain, supposed to be necessary for thioester-bond formation with ubiquitin, abolished the gene function. When a functional glutathione S-transferase (GST)-tagged hect protein was overproduced, it facilitated the protein conjugation with a myc-tagged ubiquitinRA, while this was not seen when GST-hectC3235A was overproduced. The protein conjugation with a hemagglutinin-tagged Smt3 was not affected by the overproduction of GST-hect. Taken together, we suggest that Tom1 is a ubiquitin ligase. As a multi-copy suppressor of tom1, we isolated STM3/NPI46/FPR3 which encodes a nucleolar nucleolin-like protein. We discuss possible functions of Tom1 with respect to the pleiotropic defects of nuclear division, maintenance of nuclear structure, and nucleocytoplasmic transport.

Amino Acid Sequence↗

PubMed1999

Design, synthesis, structure-activity relationships, and biological characterization of novel arylalkoxyphenylalkylamine sigma ligands as potential antipsychotic drugs.

sigma Receptor antagonists may be effective antipsychotic drugs that do not induce motor side effects caused by ingestion of classical drugs such as haloperidol. We obtained evidence that 1-(2-dipropylaminoethyl)-4-methoxy-6H-dibenzo[b,d]pyran hydrochloride 2a had selective affinity for sigma receptor over dopamine D2 receptor. This compound was designed to eliminate two bonds of apomorphine 1 to produce structural flexibility for the nitrogen atom and to bridge two benzene rings with a -CH2O- bond to maintain the planar structure. In light of the evidence, N, N-dipropyl-2-(4-methoxy-3-benzyloxylphenyl)ethylamine hydrochloride 10b was designed. Since compound 10b had eliminated a biphenyl bond of 6H-dibenzo[b,d]pyran derivative 2a, it might be more released from the rigid structure of apomorphine 1 than compound 2a. The chemical modification of compound 10b led to the discovery that N, N-dipropyl-2- [4-methoxy-3-(2-phenylethoxyl)phenyl]ethylamine hydrochloride 10g (NE- 100), the best compound among arylalkoxyphenylalkylamine derivatives 3, had a high and selective affinity for sigma receptor and had a potent activity in an animal model when the drug was given orally. We report here the design, synthesis, structure-activity relationships, and biological characterization of novel arylalkoxyphenylalkylamine derivatives 3.

Animals↗

PubMed1999

Chemical modification of apomorphine to discover sigma ligands: 6H-dibenzo[b,d]pyran and carbazole analogues.

It seems that many sigma ligands have been designed from known sigma ligands. We focused on a difference in structural flexibility between haloperidol and apomorphine, and studied chemical modification of apomorphine, a compound with high affinity for dopamine D2 receptors but not for sigma receptors, for discovery of sigma ligands. The first modification yielded good results with 6H-dibenzo[b,d]pyran analogues with weak affinity for sigma receptors but not D2 receptors. Furthermore, carbazole analogues, compounds designed from 6H-dibenzo[b,d]pyran analogues, potentially acted at sigma receptors with high selectivity. This paper describes the design, synthesis and sigma/D2 selectivity of 6H-dibenzo[b,d]pyran and carbazole analogues.

Animals↗

PubMed1999

Fluorescence in situ hybridization using 16S rRNA-targeted oligonucleotides reveals localization of methanogens and selected uncultured bacteria in mesophilic and thermophilic sludge granules.

16S rRNA-targeted in situ hybridization combined with confocal laser scanning microscopy was used to elucidate the spatial distribution of microbes within two types of methanogenic granular sludge, mesophilic (35 degrees C) and thermophilic (55 degrees C), in upflow anaerobic sludge blanket reactors fed with sucrose-, acetate-, and propionate-based artificial wastewater. The spatial organization of the microbes was visualized in thin sections of the granules by using fluorescent oligonucleotide probes specific to several phylogenetic groups of microbes. In situ hybridization with archaeal- and bacterial-domain probes within granule sections clearly showed that both mesophilic and thermophilic granules had layered structures and that the outer layer harbored mainly bacterial cells while the inner layer consisted mainly of archaeal cells. Methanosaeta-, Methanobacterium-, Methanospirillum-, and Methanosarcina-like cells were detected with oligonucleotide probes specific for the different groups of methanogens, and they were found to be localized inside the granules, in both types of which dominant methanogens were members of the genus Methanosaeta. For specific detection of bacteria which were previously detected by whole-microbial-community 16S ribosomal DNA (rDNA)-cloning analysis (Y. Sekiguchi, Y. Kamagata, K. Syutsubo, A. Ohashi, H. Harada, and K. Nakamura, Microbiology 144:2655-2665, 1998) we designed probes specific for clonal 16S rDNAs related to unidentified green nonsulfur bacteria and clones related to Syntrophobacter species. The probe designed for the cluster closely related to Syntrophobacter species hybridized with coccoid cells in the inner layer of the mesophilic granule sections. The probe for the unidentified bacteria which were clustered with the green nonsulfur bacteria detected filamentous cells in the outermost layer of the thermophilic sludge granule sections. These results revealed the spatial organizations of methanogens and uncultivated bacteria and their in situ morphologies and metabolic functions in both mesophilic and thermophilic granular sludges.

Anaerobiosis↗

PubMed1999

[Portal and pulmonary hypertension in a patient with MCTD].

A 42-year-old woman with mixed connective tissue disease (MCTD) died due to the rupture of esophageal varices. The autopsy revealed fresh thrombi in the main trunk of the portal vein. Microscopic examination disclosed wide-spread periportal fibrosis and stenosis of peripheral portal veins without remodeling of hepatic lobular architecture, which was compatible to idiopathic portal hypertension (IPH). Anti-phospholipid antibody was negative. Accordingly it is likely that portal vein thrombosis developed secondary to IPH. In the literature 6 (37.5%) of 16 collagen vascular disease patients with IPH died, and three of them were due to rupture of esophageal varices. Therefore IPH should be considered to be one of the most important complications affecting its grave prognosis in patients with collagen vascular disease. The patient also had had pulmonary hypertension (PH) when the diagnosis of portal hypertension was made. In the literature we found 5 collagen vascular disease patients with both PH and IPH like this case. The most outstanding common clinical feature among these 6 patients was Raynaud's phenomenon associated with positive anti-RNP antibody. Moreover 5 of 6 cases including this case simultaneously developed both PH and IPH. The clinical course of these patients suggests there may be a common pathogenetic factor for these two lesions. A possible candidate involved in the pathogenesis of PH and IPH may be endothelin, one of the vasoactive substances, since its receptor is said to be expressed abundantly in pulmonary and portal vasculatures. However, further investigation is necessary to elucidate the mechanism of PH and IPH in collagen vascular diseases.

Adult↗

PubMed1998

Nitric oxide modulates sympathetic control of left ventricular contraction in vivo in the dog.

Recently, evidence has been presented that nitric oxide (NO) modulates myocardial contraction induced by beta-adrenergic stimulation in vitro and in vivo. In this study, we investigated whether inhibition of the L-arginine NO system augments the positive inotropic response of the left ventricle to direct stimulation of the sympathetic nerves in vivo in the dog. Electrical stimulation was applied to the left stellate ganglion (LSG) for 1 min at submaximal (5 V, 2.5, 5 and 10 Hz) and supramaximal intensities (10 V, 10 Hz) in twelve anesthetized and vagotomized dogs. Next, in the same dogs, N(omega)-nitro L-arginine methylester (L-NAME) was infused into the left anterior descending (LAD) coronary artery, and LSG stimulation repeated using the same protocol. Finally, L-arginine was infused into the LAD artery, and LSG stimulation repeated. We used the maximum of the first derivative of left ventricular pressure (LV max d P/dt) as an index of the myocardial contractility. Plasma epinephrine and norepinephrine concentrations were measured in the coronary sinus at 5 V, 2.5 Hz before and after L-NAME treatment in five of twelve dogs. L-NAME treatment significantly augmented the inotropic response of the left ventricle (percent change in the LV max dP/dt) to LSG submaximal stimulation trains from 164 +/- 13 to.212 +/- 21 (P < 0.03), from 187 +/- 15 to 234 +/- 25 (P < 0.05) and from 220 +/- 19 to 280 +/- 33% (P < 0.05), respectively. This response was reversed by L-arginine treatment. However, the inotropic response to the supramaximal stimulation train did not change after L-NAME and L-arginine treatment. L-NAME significantly increased plasma norepinephrine concentration from 0.69 +/- 0.41 to 1.00 +/- 0.52 ng/ml without changing plasma epinephrine concentration in the coronary sinus. It is concluded that the inhibition of the L-arginine NO system augmented the positive inotropic effect on the left ventricle during sympathetic nerve stimulation in normal dogs in vivo.

Animals↗

PubMed1998

[Nonoperative management of major blunt renal lacerations with urinary extravasation: report of two cases].

Two cases of major blunt renal trauma with urinary extravasation managed by conservative treatment are presented herein. The first case: A 13-year-old girl fell from a bicycle. A computed tomographic (CT) scan showed right renal laceration with retroperitoneal hematoma. Renal arteriography showed evidence of fresh arterial bleeding without visualization of the lower pole. She was treated conservatively with superselective arterial embolization of the lower pole. She developed no urinoma with normal renal function. Renal renin and blood pressures stayed within the normal range in follow up studies. The second case: A 12-year-old boy fell from a tree and hit his right flank. A CT scan showed fragmentation of right renal cortex with retroperitoneal hematoma. He was treated conservatively as his vital signs remained stable, no active arterial bleeding was found no renal arteriography and both renal pelvis and ureters were well visualized by intra venous pyelography. Retroperitoneal hematoma was absorbed without formation of urinoma. Renal function remained within normal limits in follow up studies.

Adolescent↗

PubMed1998

[A qualitative analytical method for nonpermitted food colors by HPLC].

The Ministry of Health and Welfare has been proposed an analytical method for food colors by HPLC. Conditions in the method and modified conditions of the proposed method were applied for permitted and nonpermitted food colors, and relative retention times were obtained. The relative retention times would be a clue of the confirmation of these nonpermitted colors by other method.

Chromatography, High Pressure Liquid↗

PubMed1998

[Simultaneous analysis and detection of pesticides in fresh fruits and vegetables by HPLC and GC].

A method was established for simultaneous determination of pesticide residue in fresh fruits and vegetables by HPLC and GC. CH3CN extraction/NaCl partiton method was used in order to recover hydrophilic pesticide such as acephate, methamidophos. Dimethoate and methamidophos from okra and DDVP from strawberry were detected by GC. On the other hand confirmation method by GC and GC/MS was studied for peaks detected by HPLC with UV and/or FL detector. OPP, TBZ, imazalil chlorpyrifos etc. in citrus fruits were detected by the proposed method.

Chromatography, Gas↗

PubMed1998

[Evaluation of therapy for dilated cardiomyopathy with heart failure by iodine-123 metaiodobenzylguanidine imaging: comparison with heart rate variability power spectral analysis].

The relationship between the myocardial uptake of iodine-123 metaiodobenzylguanidine (123I-MIBG) and heart rate variability parameters has not been determined. This study determined the relationship between the change in myocardial uptake of 123I-MIBG and improvement in left ventricular function after treatment, to determine the usefulness of 123I-MIBG imaging to assess the effect of therapy on heart failure due to dilated cardiomyopathy (DCM). 123I-MIBG imaging and power spectral analysis of heart rate variability were performed before and after treatment in 17 patients with heart failure due to DCM. The following parameters were compared before and after treatment: New York Heart Association (NYHA) functional class, radiographic cardiothoracic ratio (CTR), blood pressure, echocardiographic data [left ventricular end-systolic (LVDs) and end-diastolic (LVDd) diameters, left ventricular ejection fraction (LVEF)], plasma concentrations of norepinephrine and epinephrine, heart rate variability power spectral analysis data [mean low frequency (MLF) and high frequency power (MHF)] and the myocardium to mediastinum activity ratio (MYO/M) obtained in early and late images, and washout rate calculated by anterior planar imaging of 123I-MIBG. The NYHA functional class, LVEF, LVDs, CTR, MLF and MHF improved after treatment. Early MYO/M and late MYO/M improved after treatment. The rate of increase in late MYO/M was positively correlated with the rate of improvement of LVEF after treatment. Furthermore, the late MYO/M was negatively correlated with MLF. Washout rate revealed no correlation with hemodynamic parameters. These findings suggest that late MYO/M is more useful than washout rate to assess the effect of treatment on heart failure due to DCM. Furthermore, the 123I-MIBG imaging and heart rate variability parameters are useful to assess the autonomic tone in DCM with heart failure.

3-Iodobenzylguanidine↗

PubMed1997

Production of granulocyte/macrophage and macrophage colony-stimulating factors by human thyrocytes in culture.

Monocytes/macrophages can be activated by the colony-stimulating factors (CSFs), granulocyte/macrophage CSF and macrophage CSF, and play a pivotal role in immune and inflammatory responses. We examined whether human thyrocytes can produce these CSFs. Interleukin-1 (IL-1) strongly up-regulated the gene and protein expression of the two CSFs. Interferon-gamma stimulated M-CSF expression but inversely suppressed GM-CSF expression in either basal or IL-1-stimulated condition. Thyrocytes prepared from Graves' thyroid tissues produced relatively larger amounts of GM-CSF in response to IL-1 and M-CSF in both basal and IL-1-stimulated conditions when compared to those obtained from normal and adenomatous goiter thyroid tissues. Thyrotropin attenuated M-CSF, but not GM-CSF, production. The present finding indicates that human thyrocytes themselves produce both GM-CSF and M-CSF, and thus may participate in immune and inflammatory responses through these CSFs production.

Cells, Cultured↗

PubMed1997

[Endometrioid adenocarcinoma of the prostate: a case report].

A 69-year-old man was referred to our department with gross hematuria. Magnetic resonance imaging revealed the tumor directly invading the rectum. Biopsy of the tumor by transurethral resection demonstrated endometrioid adenocarcinoma of the prostate. Serum prostate specific antigen (PSA) level was normal. Because the tumor did not respond to hormonal therapy for a month, radical prostatectomy combined with rectal amputation was performed. Immunohistochemically, carcinoembryonic antigen was detected but PSA and prostatic acid phosphatase were not.

Aged↗

PubMed1996

An anatomic study of neuropeptide immunoreactivities in the lumbar dura mater after lumbar sympathectomy.

STUDY DESIGN: The distribution and density of nerve innervation in the lumbar dura mater after lumbar sympathectomy were assessed in wistar rats. OBJECTIVE: To provide basic information on the interaction between sympathetic and sensory nerves in patients with low back pain. SUMMARY OF BACKGROUND DATA: Many studies have indicated that the sinuvertebral nerve has an important role in innervating the tissues around the vertebrae. However, the origin, innervating pattern, and connections between the nerves are still controversial. It is well known that pain is often accompanied with sympathetic symptoms and exaggerated by sympathetic stimuli. Occasionally, anesthetic block at the L2 or L3 sympathetic ganglion relieves low back pain or symptoms associated with low back pain. The authors assessed the changes of the density and distribution of nerve innervation of the lumbar dura mater after lumbar sympathectomy. METHODS: Normal adult rats were sympathectomized at L2-L3. The threshold for thermal noxious pain by hot-plate analgesia test and changes in neuropeptides in the lumbar dura mater and dorsal root ganglia using light microscopic immunohistochemistry were assessed and compared with control rats. RESULTS: In the hot-plate analgesia test, sympathectomized rats increased their hot-plate latency time compared with that of sham-operated rats. Density of calcitonin gene-related peptide immunoreactive fibers in sympathectomy side of the lumbar dura mater decreased to 45.5% compared with the contralateral side. The number and size of calcitonin gene-related peptide immunoreactive cells in dorsal root ganglia showed no difference between sympathectomized and contralateral side. CONCLUSION: Sympathectomy increased the pain threshold and made the sympathectomized rats hypesthetic. A large numbers of sensory fibers innervated the lumbar dura mater via L2-L3 sympathetic nerve in rats. Sympathectomy reduced the number of these nerve fibers in the lumbar dura mater. Sympathetic nerves may play an important role for low back pain involving the lumbar dura mater.

Animals↗