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Biomedical subjects

H Katoh

Publications and source records attributed to H Katoh.

At least 73 records · Page 4Linked to original sources
PubMed2001

Diagnosis of cardiac sarcoidosis and evaluation of the effects of steroid therapy by gadolinium-DTPA-enhanced magnetic resonance imaging.

BACKGROUND: Cardiac involvement is an important prognostic factor in patients with sarcoidosis. In this study, we evaluated the usefulness of gadolinium-DTPA (diethylene triamine pentaacetic acid)-enhanced magnetic resonance imaging (Gd-MRI) for diagnosing cardiac sarcoidosis and evaluating the effects of steroid therapy. METHODS: Sixteen patients with sarcoidosis diagnosed by histology or by Japanese Ministry of Health and Welfare criteria for cardiac sarcoidosis underwent Gd-MRI with a 1.5-Tesla superconducting magnet system using a T1-weighted spin-echo sequence. RESULTS: Gd-MRI showed localized enhancement of signal intensity, indicating interstitial edema, in the left ventricle in 8 of the 16 patients. Two patients with enhancement also had thinning of the left ventricular septal wall. After 1 month of prednisolone therapy (60 mg every other day or 30 to 40 mg every day), the localized high-intensity signals were markedly diminished in all 8 patients. CONCLUSIONS: Images of the heart obtained by Gd-MRI may reflect active inflammation with interstitial edema in patients with sarcoidosis. Gd-MRI may be a useful noninvasive method for early detection of cardiac sarcoidosis and for evaluating the effects of steroid therapy.

Adult↗
PubMed2001

Predictive value of interleukin-8 and granulocyte elastase in pulmonary complication after esophagectomy.

BACKGROUND: We investigated whether or not interleukin-8 (IL-8) and granulocyte elastase (GE) can be associated with pulmonary complication after esophagectomy (the most common cause of postoperative death). METHODS: We measured serial changes in the IL-8 concentration and GE activity in the plasma and bronchoalveolar lavage fluid (BALF) of 17 patients who had undergone esophagectomy, and examined the relationship between these mediators and postoperative pulmonary complication. RESULTS: Pulmonary complication occurred in 6 patients (35%, Pneum+ group). Plasma IL-8 increased at the end of the surgery then decreased, but there was no significant difference between the Pneum+ group and the group without pulmonary complication (11[65%], Pneum- group). IL-8 and GE in BALF were significantly higher in the Pneum+ group than in the Pneum- group on days 1 and 3 after the operation. There was a significant and positive correlation between IL-8 and GE in BALF. CONCLUSIONS: Our results indicate that IL-8 and GE in BALF may be useful for the prediction of postoperative pulmonary complication.

Aged↗
PubMed2001

Prostaglandin EP3 receptor protein in serotonin and catecholamine cell groups: a double immunofluorescence study in the rat brain.

Prostaglandin E(2) exerts diverse physiological actions in the central nervous system with unknown mechanisms. We have reported the immunohistochemical localization of the EP3 receptor, one of the prostaglandin E receptor subtypes, in various brain regions including many monoaminergic nuclei. In the present study, a double immunofluorescence technique with an antibody to EP3 receptor and antibodies to markers for monoamine neurons was employed to examine the expression of the receptor in serotonin and catecholamine neurons, and to reveal the distribution of the receptor-expressing monoamine neurons in the rat brain. Almost all serotonergic cells in the medulla oblongata (B1-B4) exhibited EP3 receptor-like immunoreactivity, whereas mesencephalic and pontine serotonergic cell groups (B5-B9) contained relatively small populations of EP3 receptor-immunoreactive cells. In the catecholaminergic cell groups, many of the noradrenergic A7 cells in the subcoeruleus nucleus showed immunoreactivity for the receptor. The locus coeruleus exhibited EP3 receptor-like immunoreactivity densely in the neuropil and occasionally in neuronal cell bodies, all of which were immunopositive for dopamine beta-hydroxylase, as observed by confocal laser microscopy. Many of the other noradrenergic and adrenergic cell groups contained small populations of EP3 receptor-like immunoreactive cells. In contrast, no EP3 receptor-like immunoreactivity was detected in the noradrenergic A2 and A4, the adrenergic C2, and all the dopaminergic cell groups. The expression of EP3 receptor by most of the serotonergic, noradrenergic and adrenergic cell groups suggests that prostaglandin E(2) modulates many physiological processes mediated by widely distributed monoaminergic projections through activation of the EP3 receptor on the monoaminergic neurons; for instance, it may modulate nociceptive and autonomic processes by affecting the descending serotonergic pathway from the raphe magnus nucleus to the spinal cord.

Animals↗
PubMed2001

High density lipoprotein binding protein of eel (Anguilla japonica) liver with specificity of binding to apoAI as a ligand.

High-density lipoprotein (HDL) binding protein (HBP) was isolated from the microsomal fraction of eel liver homogenate by affinity chromatography with a HDL-column. After SDS-PAGE and blotting, HBP on the PVDF membrane was detected by FITC-labeled HDL and apolipoprotein AI (apoAI) as a ligand. HBP in the microsomal fraction was most abundant among microsomal, mitochondrial and cytosolic fractions. The HBP isolated by a HDL-column consisted of at least three proteins with low molecular weights of 18.5, 14.5 and 13.5 kDa; the main component was 14.5 kDa. These proteins are not products of protease digestion, as the procedure was carried out in the presence of protease inhibitors including (p-aminophenyl) methansulfonyl fluoride, 4-(2-aminoethyl)-benzenesulfonyl fluoride, pepstatin A, E-64, bestatin, leupeptin, aprotinin and EDTA. The HBP specifically bound to FITC-apoAI and faintly bound or did not bind to FITC-apoAII. Furthermore, binding of HDL labeled with lipophilic fluorescence to isolated eel hepatocytes was inhibited by the antibody to apoAI, but not inhibited by the antibody to apolipoprotein AII (apoAII). These results strongly suggest that the HBP isolated from the microsomal fraction is present on the plasma membrane of eel liver and plays important roles for the lipid transport through the interaction with HDL.

Animals↗
PubMed2001

Mycobacterium tuberculosis infection within Warthin's tumor: report of two cases.

We report two patients with Warthin's tumor who were also infected with Mycobacterium tuberculosis. Case 1 was a 75-year-old woman with Warthin's tumor and multiple small epithelioid granulomas with caseous necrosis involving the submandibular gland. This patient died of tuberculous meningitis 4 months after biopsy. Case 2 was a 78-year-old man with a 10-year history of a parotid mass which had enlarged rapidly over 2 months. Surgical excision revealed Warthin's tumor and epithelioid granulomas involving the left parotid gland. DNA extracted from paraffin sections was amplified by nested polymerase chain reaction (PCR) with primer sets for the mycobacterial 65-KDa antigen gene. Restriction enzyme digestion of the PCR products could differentiate Mycobacterium tuberculosis from other mycobacteria in both cases. Although the histogenesis of lymphoid components of Warthin's tumor is controversial, the frequent prevalence of inflammation or necrosis and our present findings suggest these components have a similar behavior to regional lymph nodes.

Adenolymphoma↗
PubMed2001

Atrial fibrillation impairs endothelial function of forearm vessels in humans.

BACKGROUND: Although there have been many studies on the effects of atrial fibrillation (AF) on cardiac function, few studies have been done on its effects on endothelial function. The present study was designed to examine the effects of AF on endothelial function in human subjects. METHODS AND RESULTS: Changes in forearm blood flow (FBF) induced by acetylcholine and nitroglycerin were measured by using plethysmography in 14 patients with lone AF, 13 patients with AF and underlying heart disease, and 12 normal control subjects. In the patients, these measurements were repeated after cardioversion. Although baseline FBF was the same in the 3 groups, acetylcholine-induced increases in FBF were significantly smaller in both patient groups than in the control group, and FBF increases were particularly depressed in AF patients with underlying heart disease. After restoration of sinus rhythm by cardioversion, FBF response to the highest dose of acetylcholine increased by 46% in patients with lone AF (n = 10) and by 90% in AF patients with underlying heart disease (n = 11). Nitroglycerin-induced vasodilatation was the same in all 3 groups and was not affected by cardioversion. CONCLUSIONS: These findings suggest that endothelium-dependent vasodilatation is impaired by AF and improves after sinus rhythm is restored.

Acetylcholine↗
PubMed2001

Serum levels of myoglobin, creatine phosphokinase, and smooth muscle heavy-chain myosin in patients with ectopic pregnancy.

STUDY OBJECTIVE: Serum markers of smooth muscle destruction have been shown to be elevated in ectopic pregnancy, but they remain of questionable clinical utility. Our goal was to determine the clinical utility of 3 markers of smooth muscle destruction: creatine phosphokinase (CPK), smooth muscle heavy-chain myosin (SMHC), and myoglobin. METHODS: This was a prospective cohort study, with consecutive enrollment of all women in the first trimester of pregnancy who presented to our urban emergency department with complaints of lower abdominal pain, vaginal bleeding, or both. Patients were excluded from the study if there was a history of recent surgery or major trauma. Data analysis included receiver operating characteristic (ROC) curve, 95% confidence intervals (CIs), and a regression model. RESULTS: A total of 378 patients were enrolled, with 61 patients diagnosed with an ectopic pregnancy, and 317 patients placed in the non-ectopic pregnancy group with other diagnoses. ROC curve analysis revealed an area under the curve of 0.56 (95% CI 0.51 to 0.61) for CPK, 0.63 (95% CI 0.59 to 0.68) for SMHC, and 0.58 (95% CI 0.53 to 0.63) for myoglobin. A regression model analyzing the effects of race, maternal age, estimated gestational age, and serum levels of human chorionic gonadotropin beta-subunit found no significant confounders. CONCLUSION: Although there is a statistically significant elevation in the serum levels of SMHC, the range of values seen is too large to allow SMHC to be a useful screening tool.

Adult↗
PubMed2001

Targeted disruption of psbX and biochemical characterization of photosystem II complex in the thermophilic cyanobacterium Synechococcus elongatus.

PSII-X is a small hydrophobic protein, which is universally present in photosystem II (PSII) core complex among cyanobacteria and plants. The role of PSII-X was studied by directed mutagenesis and biochemical analysis in the thermophilic cyanobacterium Synechococcus elongatus. The psbX-disrupted mutant could grow photoautotrophically indicative of non-essential function, while it showed growth defect under low CO(2) conditions. An active O(2)-evolving PSII complex was successfully isolated from the mutant and wild type. Protein composition of the isolated PSII complex was the same as wild type except for the absence of PSII-X. O(2) evolution supported by artificial quinones was affected in the psbX-disrupted mutant. At high concentration of 2,6-dichlorobenzoquinone or 2,6-dimethylbenzoquinone, the mutant showed much lower activity than wild type, while not much difference was found at low concentration. These results imply that binding or turnover of quinones at the Q(B) site depends, at least in part, on PSII-X protein in the PSII complex. Gel filtration chromatography of the PSII complex revealed that the dimeric structure of the complex was not greatly affected in the psbX-disrupted mutant.

Amino Acid Sequence↗
PubMed2001

Functional analysis of psbV and a novel c-type cytochrome gene psbV2 of the thermophilic cyanobacterium Thermosynechococcus elongatus strain BP-1.

Cytochrome c-550 is an extrinsic protein associated with photosystem II (PSII) in cyanobacteria and lower eukaryotic algae and plays an important role in the water-splitting reaction. The gene (psbV) for cytochrome c-550 was cloned from the thermophilic cyanobacteria Thermosynechococcus (formerly Synechococcus) elongatus and T. (formerly Synechococcus) vulcanus. In both genomes, located downstream of psbV were a novel gene (designated psbV2) for a c-type cytochrome and petJ for cytochrome c-553. The deduced product of psbV2 showed composite similarities to psbV and petJ. Phenotype of psbV-disruptant in Thermosynechococcus was practically the same as that reported in Synechocystis sp. PCC 6803. Either psbV or psbV2 gene of T. elongatus was expressed in the psbV-disruptant of Synechocystis sp. PCC 6803, which resulted in recovery of the photoautotrophic growth. However, the enhanced requirement of Ca(2+) or Cl- ions in the psbV-disruptant of Synechocystis was suppressed by expression of psbV but not by expression of psbV2. Thus, it is concluded that psbV2 can partly replace the role of psbV in PSII. The close tandem arrangement of psbV/psbV2/petJ implies that psbV2 was created by gene duplication and intergenic recombination during evolution.

Amino Acid Sequence↗
PubMed2001

Iron-binding activity of FutA1 subunit of an ABC-type iron transporter in the cyanobacterium Synechocystis sp. Strain PCC 6803.

The futA1 (slr1295) and futA2 (slr0513) genes encode periplasmic binding proteins of an ATP-binding cassette (ABC)-type iron transporter in Synechocystis sp. PCC 6803. FutA1 was expressed in Escherichia coli as a GST-tagged recombinant protein (rFutA1). Solution containing purified rFutA1 and ferric chloride showed an absorption spectrum with a peak at 453 nm. The absorbance at this wavelength rose linearly as the amount of iron bound to rFutA1 increased to reach a plateau when the molar ratio of iron to rFutA1 became unity. The association constant of rFutA1 for iron in vitro was about 1 x 10(19). These results demonstrate that the FutA1 binds the ferric ion with high affinity. The activity of iron uptake in the Delta futA1 and Delta futA2 mutants was 37 and 84%, respectively, of that in the wild-type and the activity was less than 5% in the Delta futA1/Delta futA2 double mutant, suggesting their redundant role for binding iron. High concentrations of citrate inhibited ferric iron uptake. These results suggest that the natural iron source transported by the Fut system is not ferric citrate.

ATP-Binding Cassette Transporters↗
PubMed2001

Genes essential to iron transport in the cyanobacterium Synechocystis sp. strain PCC 6803.

Genes encoding polypeptides of an ATP binding cassette (ABC)-type ferric iron transporter that plays a major role in iron acquisition in Synechocystis sp. strain PCC 6803 were identified. These genes are slr1295, slr0513, slr0327, and recently reported sll1878 (Katoh et al., J. Bacteriol. 182:6523-6524, 2000) and were designated futA1, futA2, futB, and futC, respectively, for their involvement in ferric iron uptake. Inactivation of these genes individually or futA1 and futA2 together greatly reduced the activity of ferric iron uptake in cells grown in complete medium or iron-deprived medium. All the fut genes are expressed in cells grown in complete medium, and expression was enhanced by iron starvation. The futA1 and futA2 genes appear to encode periplasmic proteins that play a redundant role in iron binding. The deduced products of futB and futC genes contain nucleotide-binding motifs and belong to the ABC transporter family of inner-membrane-bound and membrane-associated proteins, respectively. These results and sequence similarities among the four genes suggest that the Fut system is related to the Sfu/Fbp family of iron transporters. Inactivation of slr1392, a homologue of feoB in Escherichia coli, greatly reduced the activity of ferrous iron transport. This system is induced by intracellular low iron concentrations that are achieved in cells exposed to iron-free medium or in the fut-less mutants grown in complete medium.

Biological Transport↗
PubMed2001

Positive and negative effects of nitric oxide on Ca(2+) sparks: influence of beta-adrenergic stimulation.

Nitric oxide (NO) can have a positive or negative effect on cardiac contractility and the ryanodine receptor (RyR). This dual effect has been explained as being dependent on the concentration of NO. We find that cellular RyR response to NO is also dependent on the degree of beta-adrenergic stimulation, and thus the state of protein kinase A activation. Ca(2+) spark frequency (CaSpF) in rat ventricular myocytes was used as an index of resting RyR activity. CaSpF response to beta-adrenergic stimulation was used as an index of protein kinase A activation. High concentration of isoproterenol, a beta-adrenergic agonist, caused a large increase in CaSpF; addition of NO (spermine NONOate, 300 microM) then caused a decrease in CaSpF. Low concentration of isoproterenol produced only a slight increase in CaSpF, but the same NO concentration now caused a large increase in CaSpF. A dual effect was also observed in twitch. Thus the net direction of the effects of NO on RyR activity and Ca(2+) transients (directly or by alteration of sarcoplasmic reticulum Ca(2+) load) can be reversed, depending on the ambient level of beta-adrenergic activation.

Adrenergic beta-Agonists↗
PubMed2001

Possible involvement of Rho kinase in Ca2+ sensitization and mobilization by MCh in tracheal smooth muscle.

We examined the effects of Rho kinase on contraction and intracellular Ca2+ concentration ([Ca2+](i)) in guinea pig trachealis by measuring isometric force and the fura 2 signal [340- to 380-nm fluorescence ratio (F340/F380)]. A Rho kinase inhibitor, Y-27632 (1-1,000 microM), inhibited methacholine (MCh)-induced contraction, with a reduction in F340/F380 in a concentration-dependent manner. The values of EC(50) for contraction and F340/F380 induced by 1 microM MCh with Y-27632 were 27.3 +/- 5.1 and 524.1 +/- 31.0 microM, respectively. With 0.1 microM MCh, the values for these parameters were decreased to 1.0 +/- 0.1 and 98.2 +/- 6.2 microM, respectively. Tension-F340/F380 curves for MCh indicated that Y-27632 caused an ~50% inhibition of MCh-induced contraction, without a reduction in F340/F380. These effects of Y-27632 were not inhibited by a protein kinase C inhibitor, GF-109203X. Our results indicate that inhibition of Rho kinase attenuates both Ca2+ sensitization and [Ca2+](i).

Amides↗
PubMed2001

A rare case of bronchial glomus tumor.

A 48-year-old man was admitted because of bloody sputum in whom a chest computed tomography (CT) scan and fiberoptic bronchoscopy demonstrated a polypoid tumor in the left main bronchus. The tumor was surgically resected, and the pathological and immunohistochemical findings led to diagnosis of the tumor as a bronchial glomus tumor.

Biopsy, Needle↗
PubMed2001

Cisternal MHPG level inversely correlates with Glasgow coma scale after aneurysmal subarachnoid hemorrhage.

We measured the concentrations of monoamines and amino acids in the cisternal cerebrospinal fluid obtained from 15 patients after aneurysmal subarachnoid hemorrhage. Based on the Glasgow Coma Scale (GCS), the patients were divided into two conscious (GCS always 14 or better from the third post-operative day to Day 12; n = 8) and unconscious groups (n = 7). We examined the concentrations of monoamines and amino acids between the two groups and evaluated the correlation between the concentrations and the GCS at CSF sampling. The concentration of MHPG was significantly higher in the unconscious than in the conscious group from Days 4 to 12. A significant inverse correlation was observed between the MHPG concentration and the GCS (r = approximately 0.635, p < 0.0001). Measuring the cisternal MHPG concentration may be useful for estimating convalescence after subarachnoid hemorrhage.

Aged↗