Search PubMed⌕ Search

Biomedical subjects

R Itoh

Publications and source records attributed to R Itoh.

At least 127 records · Page 7Linked to original sources

[CT findings of pulmonary infections].

Although many pulmonary infections are diagnosed using chest radiographs in combination with clinical findings and are treated empirically with antibiotics, there are situations in which chemotherapy is not effective and further examinations are necessary. In those cases, CT, especially high-resolution CT (HRCT), can provide additional information about detailed morphological changes of the lung that are sometimes indicative of the causative organisms of pneumonia, such as pulmonary tuberculosis. Although it is true that the same organism can present a wide spectrum of radiological findings, it is also important for differential diagnosis to understand the basic features of pathological changes of the lung and the CT findings caused by each of the various organisms. Such CT information would also be useful in differentiating infectious pneumonia from noninfectious pneumonia. This review article presents the principal CT findings of pulmonary infections and their pathological correlations with various pneumonias, including bacterial, tuberculous, fungal, and viral pneumonias.

Bronchi↗

Atypical Rathke's cleft cyst associated with ossification.

We report a case of symptomatic Rathke's cleft cyst with ossification. CT scans showed curvilinear calcification on the wall of the cyst. MR images revealed a cystic sellar lesion with a nodular solid mass extending to the floor of the third ventricle. This case shows that calcification of the suprasellar cyst does not always suggest craniopharyngioma. Rathke's cysts should be histologically differentiated from craniopharyngiomas because their treatments are different.

Adult↗

[PMC (pharmacokinetic modulating chemotherapy) for advanced gastric cancer].

We performed pharmacokinetic modulating chemotherapy (PMC) postoperatively in patients with advanced gastric cancer and examined its antitumor and the side effects. Nineteen patients with advanced gastric cancer (all were above Stage II) were treated: 10 had undergone total gastrectomy and 9 distal gastrectomy. UFT (400 mg/day) was orally administered daily and a continuous infusion of 5-FU (600 mg/m2/24 hr) was given once a week. The average observation period was 14.26 months (4-30 months). All patients with Stage II or III disease have survived, but two patients with Stage IV disease died. One patient received insufficient PMC and the other had a liver metastasis. Two patients experienced Grade 3 inappetence, but all other side effects were Grade 2 or lower and the incidence was less than 25%. In conclusion. PMC has tolerable side effects and may be effective in postoperative chemotherapy for advanced gastric cancer.

Administration, Oral↗

Delta-9 fatty acid desaturase gene containing a carboxyl-terminal cytochrome b5 domain from the red alga Cyanidioschyzon merolae.

A delta-9 fatty acid desaturase gene, homologous to animal and fungal acyl-coenzyme A (CoA) desaturases, was isolated from the red alga Cyanidioschyzon merolae using a degenerate PCR strategy. This gene, designated as CmFAD9, has no intron. The encoded delta-9 fatty acid desaturase (CmFad9p) consists of 476 amino acids and has an estimated molecular mass of 55.4 kDa. CmFad9p is a unique delta-9 fatty acid desaturase among plants, in that it is fused with the cytochrome b5 domain at its carboxyl terminus. This is characteristic of yeast acyl-CoA desaturase. Genomic Southern hybridization suggested that the C. merolae genome contains a single gene for delta-9 fatty acid desaturase of the animal and fungal type. Southern hybridization combined with pulsed-field gel electrophoresis revealed that CmFAD9 is probably located on chromosome XI of the 17 C. merolae chromosomes. A 1.6-kb product of this gene was transcribed throughout a light/dark synchronization culture. The discovery of CmFAD9 indicates the existence of a novel type of plant delta-9 fatty acid desaturase that may function in the endoplasmic reticulum, but not in the plastid.

Amino Acid Sequence↗

The division apparatus of plastids and mitochondria.

Mitochondria and plastids in eukaryotic cells contain distinct genomes and multiply in the cytoplasm by binary division of preexisting organelles. Mitochondrial and plastid nuclei are easily visualized as compartments in the matrix of organelles by high-resolution fluorescence microscopy and by immunoelectron microscopy using anti-DNA antibodies. Plastid and mitochondrial division can be clearly separated into two main events: division of the organelle nuclei, and then division of the rest of the organelles, the process of organellokinesis (mitochondriokinesis and plastidokinesis). The mechanical apparatus that regulates organellokinesis has remained undetermined. In 1986, the plastid-dividing apparatus (PD ring) for plastidokinesis was first identified by us in the primitive red alga Cyanidium caldarium RK-1. The PD ring is located in the cytoplasm outside the organelle envelope at the constricted isthmus of dividing organelles and has subsequently been found in all eukaryotic plants examined. We were also the first to identify the mitochondrion-dividing apparatus (MD ring) for mitochondriokinesis in the unicellular red alga Cyanidioschyzon merolae in 1993. Eukaryotic cell division is therefore controlled by at least three dividing apparata (rings), a contractile ring, an MD ring, and a PD ring, while bacterial division is controlled by a single bacterial contractile FtsZ ring. The aims of this review are to present the fine structure, process of formation, and contraction of the organelle-dividing apparatus, focusing on evolutionary conservation and diversion from the bacterial contractile ring.

Cell Division↗

Dietary protein intake and urinary excretion of calcium: a cross-sectional study in a healthy Japanese population.

To evaluate whether habitual excess protein intake is a significant risk factor for calcium loss, we studied the relation between urinary excretion of calcium and protein intakes, in 349 male and 406 female Japanese aged 20-79 y. The subjects were apparently healthy, free-living, and consuming diets of their own choosing. We divided the subjects into two groups: those aged 20-49 y and those aged 50-79 y. In each group, we observed a significant positive correlation between daily urinary excretion of calcium and protein intake. Calcium excretion also correlated positively with daily urinary excretion of urea. Multivariate analyses revealed that in each age group the relation between calcium excretion and urea excretion remained significant even after sex, age, body weight, urinary sodium excretion, and calcium intake were adjusted for. The correlation of calcium excretion with animal protein intake was significantly positive in both sexes and in each age group whereas that with plant protein was not. We observed a significant positive correlation between daily calcium excretion and daily urinary excretion of sulfate. The correlation in 50-79-y old subjects remained significant even after sex, age, body weight, sodium excretion, and calcium intake were adjusted for. Our findings suggest that excess protein, especially that rich in sulfur-containing amino acids, in habitual diets may augment calcium excretion in the urine, at least in the elderly.

Adult↗

Mutations in PEX10 is the cause of Zellweger peroxisome deficiency syndrome of complementation group B.

Peroxisome biogenesis disorders (PBD), such as Zellweger syndrome, are autosomal recessive diseases caused by a deficiency in peroxisome assembly as well as a malfunction of the peroxisomes, where at least 10 genotypes have been reported. We have isolated a human PEX10 cDNA (HsPEX10) by an expressed sequence tag homology search on a human DNA database using yeast PEX10 from Hansenula polymorpha, followed by screening of a human liver cDNA library. This cDNA encodes a peroxisomal protein (a peroxin Pex10p) comprising 326 amino acids, with two putative transmembrane segments and a C3HC4zinc finger RING motif. Both the N- and C-terminal regions of Pex10p are exposed to the cytosol, as assessed by an expression study of epitope-tagged Pex10p. HsPEX10 expression morphologically and biochemically restored peroxisome biogenesis in fibroblasts from Zellweger patients of complementation group B in Japan (complementation group VII in the USA). One patient (PBDB-01) possessed a homozygous, inactivating mutation, a 2 bp deletion immediately upstream of the RING motif, which resulted in a frameshift, altering 65 amino acids from the normal. This implies that the C-terminal part, including the RING finger, is required for biological function of Pex10p. PEX10 cDNA derived from patient PBDB-01 was defective in peroxisome-restoring activity when expressed in patient fibroblasts. These results demonstrate that mutation in PEX10 is the genetic cause of complementation group B PBD.

Amino Acid Sequence↗

Postoperative sella: evaluation with fast spin echo T2-weighted high-resolution imaging.

OBJECTIVE: The purpose of this study was to investigate the magnetic resonance features of the postoperative sella with fast spin echo (FSE) T2-weighted high-resolution imaging and to evaluate the benefits of the sequence using a follow-up magnetic resonance imaging protocol after transsphenoidal surgery. METHODS: Coronal spin echo (SE) T1-weighted and FSE T2-weighted images were prospectively obtained in 24 patients after surgery for pituitary adenomas. We observed the signals and the contour of normal structures, fluid collection, implanted materials, and mass lesions, including granulation tissue and adenoma. RESULTS: The pituitary gland was delineated in 51 of 59 FSE T2-weighted images, 90.2% of which presented clear boundaries. Whereas the gland was detected in 49 of 58 SE T1-weighted images, only 20.4% showed the boundaries. A mass lesion was identified in each of 12 patients with good resolution on FSE T2-weighted images. SE T1-weighted images detected mass lesions in 7 of 12 patients without distinctive boundaries. Contrast enhancement had little advantage in clarifying the boundaries between normal and abnormal structures. For the detection of mass lesions in the sella, the kappa values for interobserver agreement were 0.8 for FSE T2-weighted images and 0.25 for SE T1-weighted images. CONCLUSION: FSE T2-weighted imaging is a reliable method with which to assess the sella with sufficient resolution after transsphenoidal surgery. The combination of unenhanced SE T1-weighted and FSE T2-weighted images may reduce the use of contrast material after pituitary surgery.

Adenoma↗

Isolation and characterization of a wound-inducible ribonuclease from Nicotiana glutinosa leaves.

A wound-inducible ribonuclease (RNase NW) was purified from leaves of Nicotiana glutinosa. The purified RNase NW has an optimum pH around 5 and 7, and its base specificity is suggested based on the relative rates of hydrolysis of homopolyribonucleotides to be a preference for guanine base. The complete amino acid sequence of RNase NW was deduced by a combination of protein and cDNA sequencings. The cDNA sequence includes the entire coding sequence for a polypeptide with 229 amino acids including a putative secretion signal peptide at the N-terminus composed of 25 amino acids. The amino acids identified by the protein chemical methods are unambiguously localized within the deduced amino acid sequence from the cDNA sequence. Comparison of the sequence of RNase NW with those of other known plant RNases showed that it was identical except for eight residues to that of N. alata RNase NE, which is present in the style and pollen under normal conditions and is induced in roots in response to phosphate starvation [Dodds et al., Plant. Mol. Biol., 31, 227-238 (1996)]. RNase NW shows considerable sequence similarity to other known RNases, sharing 57% to 84% identical residues. Northern blot analysis using an RNase NW cDNA fragment as a probe showed that the RNase NW transcript was not detected in leaves without wounding, but it was induced within 4 h after wounding and then gradually decreased during 20 h.

Amino Acid Sequence↗

[Successful syngeneic peripheral blood stem cell transplantation for protracted myelosuppression after chemotherapy in a patient with acute myelogenous leukemia].

Acute myelogenous leukemia (M2) with translocation of 8;21. Was diagnosed in 61-year-old man. He was successfully treated and obtained complete remission. After consolidation therapy, myeloid suppression and maturation arrest at the myelocyte level were recognized. Following intensive chemotherapy, he received rhG-CSF-mobilized peripheral blood stem cell transplantation (PBSCT) from an identical twin because he had life threatening infectious events and protracted myelosuppression. Transplantation of 2.5 x 10(6)/kg CD34+ cells resulted in a rapid normal tri-lineage hematologic reconstitution. Syngeneic PBSCT appears to be a substitute for syngeneic bone marrow transplantation in certain situations.

Antineoplastic Combined Chemotherapy Protocols↗

[Successful emergency operation for massive hemorrhage due to jejunal angiodysplasia after intensive chemotherapy in a patient with refractory anemia with excess of blasts].

A 59-year-old man was referred to our hospital because of pancytopenia. Peripheral blood examination showed a WBC of 1,500/microliters with 2% blasts, Hb 8.1 g/dl and a platelet count of 4.1 x 10(4)/microliters. A bone marrow aspiration revealed hyperplasia with proliferation of blasts (15.7%) and myelodysplasia. Chromosome analysis revealed multiple aberrations, including -5, -7, +8. The patient was given a diagnosis of refractory anemia with excess of blasts (RAEB) and treated with combination chemotherapy. Agranulocytosis and high fever remained after chemotherapy, and abdominal pain and diarrhea developed. An abdominal X-ray film and computed tomography scan demonstrated dilated small bowel, thickness of the bowel wall, and ascites. A diagnosis of neutropenic enterocolitis was given. During the WBC recovery period from nadir, massive hematochezia developed in the patient. Angiography detected the leakage of contrast medium from a peripheral region of the first jejunal artery into the jejunal lumen. A partial resection of the jejunum was thus performed, and a histological examination revealed the presence of irregularly dilated blood vessels in the submucosal layer. These findings were consistent with the features of angiodysplasia, and indicate that angiodysplasia should be considered one cause of intestinal hemorrhage in elderly patients during intensive chemotherapy.

Anemia, Refractory, with Excess of Blasts↗

[The relationship between subjective sleepiness and polysomnographic findings in sleep apnea syndrome].

We investigated factors of daytime sleepiness in 22 middle-aged male patients with sleep apnea syndrome (SAS) using the Epworth sleepiness scale (ESS) and polysomnography. The subjects were classified into two groups according to ESS score as follows; low ESS group: ESS score < 10, and high ESS group; ESS score > or = 10. ESS score was significantly correlated with duration in which nocturnal oxygen saturation decreased below 90% (Time of SpO2 < 90%) (r = 0.54, p < 0.05). Time of SpO2 < 90% and percent of movement arousals at the termination of apnea/hypopnea (number of movement arousal/total number of apnea/hypopneas x 100) were significantly higher in high ESS group than in low ESS group. Our findings suggest that the severity of oxygen desaturation and sleep fragmentation caused by arousal response at the termination of apnea/hypopnea may be important factors of daytime sleepiness in patients with SAS.

Aged↗

Role for C-MPL and its ligand thrombopoietin in early hematopoiesis.

Proto-oncogene c-mpl is structurally homologous with the hematopoietic growth factor receptor superfamily. The ligand for c-mpl was purified and its gene cloned. Extensive functional studies revealed that the ligand for c-mpl plays a crucial role in megakaryocytopoiesis and platelet production, hence, this ligand proved to be the long-sought hematopoietin, thrombopoietin (TPO). We briefly review here the role for TPO in early hematopoiesis, based on our in vitro data obtained using a serum-free culture system. TPO in combination with the ligand for c-kit (SF) or interleukin-3 (IL-3) but not TPO alone supported the growth of murine primitive hematopoietic progenitors. Studies on lineage expression indicated that the progenitors supported by TPO plus SF or TPO plus IL-3 are multipotential. Delayed addition experiments demonstrated that TPO has the potential to effectively support the survival of primitive hematopoietic progenitors. TPO also hastened IL-3-dependent growth of progenitors by shortening the time required for cell-cycling. While size of the colonies did not differ between colonies supported by IL-3 alone and those supported by IL-3 plus TPO, the incidence of megakaryocyte-containing colonies in cultures supported by IL-3 plus TPO was higher than that in cultures supported by IL-3 alone. Taken together, TPO as a single factor can support the survival of hematopoietic progenitors and TPO synergizes with SF or IL-3 to be active on early multipotential hematopoietic progenitors. These findings suggest that the function of TPO initially thought to be restricted to the megakaryocytic lineage proved to be greater in hematopoiesis. Reports from other laboratories regarding the involvement of TPO in early hematopoiesis are also discussed.

Animals↗

Stage-specific cell-cycling of hematopoietic progenitor cells.

We studied the growth of hematopoietic progenitors at different progressive stages of differentiation and focused especially on changes in cell-cycling. Hematopoietic progenitors from 5-fluorouracil (5-FU)-treated mice were separated into three groups on the basis of differentiation, Stages I, II, and III, and have studied their cell-cycling. Primary marrow cells collected from 5-FU-treated mice were categorized as Stage I progenitors. Stages II and III progenitors are early and late progenies of Stage I progenitors, respectively. The rate of growth of hematopoietic progenitors supported by interleukin-3 (IL-3) and steel factor (SF) was estimated by sequential analysis of colony formation and studying replating efficiency of individual colonies. The time required for hematopoietic progenitors to go through the cell-cycle shortened as their stage of differentiation progressed. Similar results were obtained with other growth factor combinations. The analysis of DNA content of cells suggests that shortening of cell-cycling is mainly due to a decrease in the time of G1 phase of the cell-cycle. Our results demonstrate that in early hematopoiesis, the cell-cycling of hematopoietic progenitors accelerates as they differentiate.

Animals↗

DNA gyrase involvement in chloroplast-nucleoid division in Cyanidioschyzon merolae.

Cyanidioschyzon merolae is a unicellular alga with one chloroplast and one mitochondrion per cell. Each of these organelles has a simple nucleoid located in the central area. Prior to mitosis and cytokinesis, both the division of organelle nucleoids and organellokinesis occur simultaneously. We investigated the effects of nalidixic acid, an inhibitor of DNA gyrase, on the replication and division of organelle nucleoids. Using microfluorometry, we monitored the synthesis of organelle DNA (organelle S phase) in synchronous cultures. In both the chloroplast and the mitochondrion, DNA synthesis occurred from the start of the light period and ceased within 3 h. The addition of nalidixic acid at the start of the light period inhibited DNA synthesis in both organelles. Next, we added nalidixic acid to the synchronous culture at the beginning (just before the organelle S phase) or at the end (organelle G2 phase) of the light period and monitored the division of organelle nucleoids in the dark period. Approximately 50 to 70% of chloroplast nucleoids divided unequally in both experiments. Despite the unequal division of the chloroplast nucleoids, electron microscopy revealed that the chloroplasts were divided into equal daughter chloroplasts by the chloroplast-divided ring. During the same treatments, all of the mitochondrial nucleoids underwent normal and equal division. Our results suggest the involvement of DNA gyrase in the replication of chloroplast and mitochondrial DNA and in the division of the chloroplast nucleoid, as well as a difference in mechanism between the division of chloroplast and mitochondrial nucleoids.

Anti-Infective Agents↗

[Evaluation of electrocardiographic left ventricular hypertrophy with both QRS voltage and ST-T change using echocardiography].

The purpose of the present study is to determine whether electrocardiographic QRS voltage criteria with ST-T change is useful in the diagnosis of left ventricular hypertrophy (LVH) using echocardiography. One hundred men including 59 with hypertension (HT), 9 with hypertrophic cardiomyopathy (HCM), and 32 without any cardiovascular disease were enrolled in this study. All of them had the electrocardiographic evidence of LVH by Sokolow-Lyon voltage criteria (RV5 or RV6 > 2.6 mV, SV1+RV5 or SV1+RV6 > or = 3.5 mV). They were classified into three groups based on ST-T pattern as follows: Normal ST-T (group N): normal ST-T in twelve leads; Early strain ST-T (group ES): ST depression, flat T (T/R < 1/10), diphasic T or T wave inversion < 0.1 mV in V5 or V6; and Strain ST-T (group S): inverted T wave in V5 and V6. Echocardiographic LVH was determined when either interventricular septal thickness (IVST) or left ventricular posterior wall thickness (LVPWT) > or = 12 mm was present. According to this echocardiographic evidence, 31.7%(20/63) of group N, 75.0% (12/16) of group ES, and 100% (21/21) of group S were diagnosed. There were significant correlations between QRS voltage indices (RV5, RV6, SV1+RV5 and SV1+RV6) and IVST, (IVST+LVPWT)/2, and LV mass in group S(r = 0.650 to 0.858, p < 0.05) but not in group N. Values for IVST and LV mass were significantly greater in group S than in group ES or N. The electrocardiographic diagnosis of LVH with both QRS voltage and ST-T change thus appeared to be more useful than that with QRS voltage criteria alone.

Adult↗

Mechanism of the reaction catalysed by cytosolic 5'-nucleotidase/phosphotransferase: formation of a phosphorylated intermediate.

Cytosolic 5'-nucleotidase preferentially catalysing the hydrolysis of IMP, GMP and their deoxy derivatives, and endowed with phosphotransferase activity, was purified from calf thymus and its reaction mechanism was studied. In the presence of [32P]IMP, ATP and MgCl2, a covalent enzyme-phosphate intermediate was trapped by mixing with an SDS solution. Heart or acid treatment of the enzyme before incubation with radiolabelled substrate prevented formation of the intermediate. Furthermore, on the basis of studies on the kinetic parameters of the enzyme as function of pH, and of experiments on thiol oxidation and photo-oxidation, we suggest the involvement of cysteine and histidine residue(s) in the reaction mechanism.

5'-Nucleotidase↗

Accelerated cell-cycling of hematopoietic progenitors by the flt3 ligand that is modulated by transforming growth factor-beta.

Although hematopoietic growth factors have been extensively studied as to their roles in recruitment of hematopoietic progenitors from quiescence state to cell division state, little is known of their effects on cell-cycling of progenitors that have already transited from quiescence into active cell-cycling. We examined the effects of the flt3 ligand (FL) on cell-cycling of hematopoietic progenitors in serum-free culture. Results from our serial observations of colony formation and replating experiments suggest that FL enhances the rate of growth of interleukin-3 (IL-3)-dependent colonies by shortening the time for each progenitor in the colonies to divide. Cell-cycle analysis showed that shortening of cell-cycle time induced by FL is mainly because of alteration in the G1 phase that hematopoietic progenitors go through. We next investigated the role of transforming growth factor-beta (TGF-beta) in cell-cycling of progenitors, using TGF-beta protein and TGF-beta antisense oligonucleotides, because mRNA of TGF-beta was detected by reverse transcriptase polymerase reaction in blast cells that we used as a source of progenitors. TGF-beta lengthened the time required for IL-3-dependent progenitors to become two daughter cells, whereas the effects of TGF-beta antisense oligonucleotides were opposite to those of TGF-beta. The addition of TGF-beta neutralizing monoclonal antibodies to the cultures resulted in effects similar to those seen with TGF-beta antisense oligonucleotides. DNA studies indicated that both TBF-beta and TGF-beta antisense oligonucleotides change the length of G1 phase of the cell-cycle. TGF-beta abrogated the effects of FL on the growth rate of hematopoietic progenitors, whereas the combination of FL with TGF-beta antisense oligonucleotides exerted additive effects. These data show that FL has the potential to accelerate cell-cycling of hematopoietic progenitors, which is susceptible to the modulation by TGF-beta.

Animals↗