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Biomedical subjects

H Itoh

Publications and source records attributed to H Itoh.

At least 325 records · Page 18Linked to original sources
PubMed1999

Helicobacter pylori infection reduces intraluminal nitric oxide in humans.

It has recently been demonstrated that nitric oxide (NO) is highly concentrated in the gastric lumen and plays an important role in defending against pathogenic microorganisms in the stomach. NO in the gastric lumen is mainly delivered by extrinsic sources from saliva. We studied whether Helicobacter pylori infection affected intraluminal NO levels in humans. H. pylori infection was diagnosed on the basis of histology and culture or (13C)-urea breath test. Air and gastric juice in the gastric lumen were collected endoscopically. The concentration of intraluminal NO was measured by a chemiluminescence system, using an NO analyzer. The concentration of nitrite in gastric juice was measured by the Griess reaction. The intraluminal concentration of NO in H. pylori-positive patients (198.2 +/- 41 parts per billion [ppb] mean +/- SE; n = 70) was significantly lower than that in H. pylori-negative patients (353.0 +/-57.9ppb; n = 43; P < 0.05). In contrast, the concentration of nitrite in gastric juice in H. pylori-positive patients (57.7 +/- 12.3 RM; n = 70) was significantly higher than that in H. pylori-negative patients (25.9 +/- 6.4 microM; n = 43, P < 0.01). The intraluminal concentration of NO in H. pylori-positive patients was markedly increased and the concentration of nitrite in H. pylori-positive patients was markedly decreased following the completion of eradication therapy. Based on these results, we propose that a decrease in NO and excess nitrite production in the gastric lumen are associated with H. pylori infection and may play an important role in the pathogenesis of H. pylori-related abnormalities.

Female↗
PubMed1999

Nontraumatic lumbar vertebral compression fracture as a risk factor for femoral neck fractures in involutional osteoporotic patients.

To screen a potential risk factor for femoral neck fracture, we characterized lumbar vertebral fractures in 120 patients with femoral neck fractures (19 men, 101 women; mean age, 78.7 years) by investigating the frequency of patients with lumbar vertebral fracture, the number of vertebral fractures per patient, and the severity of deformity of the fractured vertebral bodies. These findings were compared with data gathered from a population of age- and sex-matched control patients (20 men, 89 women; mean age, 77.6 years) who had no evidence of femoral neck fracture. The heights of the anterior and posterior walls together with the midpart of the lumbar vertebrae were measured on lateral radiographs to identify fractures. The extent of height loss in the fractured vertebrae was calculated for each group. The incidence of patients with vertebral compression fractures was significantly higher in the femoral neck fracture group than in the control group (65.0% vs 41.1%). In terms of age, the difference in the incidence of vertebral fractures in the two groups was greater in the less aged (60-79 years old) than in the more aged (>80 years old) population. The mean number of lumbar vertebral fractures was also significantly greater in the femoral neck fracture group than in the control group (1.59 +/- 1.39 vs 0.75 +/- 1.19; P < 0.001). The incidence of more deformed vertebral fractures, which were defined as a vertebral height loss of more than 50%, was also significantly higher in the group with femoral neck fracture than in the control group (23.0% vs 7.3%). Based on these results, we concluded that multiple and more severely deformed vertebral fractures might represent a high risk for femoral neck fracture, particularly in patients less than 79 years of age. Care measures that encompass fall prevention and protection of proximal femurs in addition to drug therapy for osteoporosis should be recommended to individuals in this category.

Age Factors↗
PubMed1999

Accurate pedicle screw insertion under the control of a computer-assisted image guiding system: laboratory test and clinical study.

We used a commercially available computer-assisted navigation system (StealthStation; Sofamor Danek, Memphis, TN, USA) in both an in-vitro and a clinical study performed in 1996-1998. The basic data used for navigation were preoperative computed tomography (CT) scan imaging data. The position of the probe or drill guide was superimposed in real-time on a monitor. For the in-vitro study, ten plastic lumbar spine models (50 vertebrae) were used. The entrance hole for the screw was made by drilling, following navigation. Using the navigation system, we drilled 88 holes through the pedicles into the vertebral bodies of 44 vertebral models. All 88 pedicle holes were contained within the pedicle without perforation. The mean deviation of the hole positions from the surgical plan was 1.78 +/- 0.81 mm, and the mean angular deviation was 2.28 degrees +/- 1.92 degrees. In 29 patients, using the navigation system, we introduced 169 pedicle screws at the planned position. Fifty-one screws were used for thoracic and 118 screws for lumbar spinal fixation. All screws correctly passed through the pedicles. There were no neurological complications after surgery. Using this guided surgery system, we achieved satisfactory results both in the laboratory and in a clinical setting.

Adolescent↗
PubMed1999

Calcium phosphate-mediated transfection of primary cultured brain neurons using GFP expression as a marker: application for single neuron electrophysiology.

We investigated the efficiency of transfecting primary cultured rat postnatal brain neurons (substantia nigra pars compacta neurons and locus coeruleus neurons) with cDNA encoding GFP (jellyfish green fluorescent protein) using a calcium phosphate method. The proportion of transfected neurons (transfection efficiency) was approximately 5%, when cultures from the substantia nigra pars compacta were transfected 3 days after plating. The transfection efficiency decreased when cultures were transfected 10 days after plating (1.7%). Neurons were cotransfected at a very high probability ( > 78%) with the muscarinic m2-receptor cDNAs together with GFP plasmids. Transfected neurons were very healthy as indicated by the zero-current potential and the microscopical appearance. Because the transfection efficiency is low, this method cannot be used for experiments involving the whole cell population. The transfection efficiency of 1.7% corresponded to approximately 20 transfected cells per dish in our culture conditions and these cells are sufficient in number for electrophysiological studies. Therefore, this is an excellent method for studying the influence of exogenous genes on single neurons using electrophysiological techniques.

Animals↗
PubMed1999

Vascular stress response and endothelial vasoactive factors for vascular remodelling.

In response to several vascular stresses caused by hyperglycaemia, hypertension or hyperlipidemia, endothelial cells (EC) sense these stresses as oxidative stress to secrete several autocrine/paracrine factors, including growth factors/cytokines and vasoactive peptides to regulate vascular tone and remodelling. Vascular stresses induce co-ordinate gene regulation of endothelial vasoactive substances and their related enzymes to cause vasorelaxation and vascular growth inhibition. We speculate that prolonged and excessive vascular stresses impair endothelial function, which results in the imbalance of endothelial production of vasoactive substances and leads to the formation of proliferative vascular lesions.

Animals↗
PubMed1999

Fast magnetic resonance imaging of the lung.

The impact of fast MR techniques developed for MR imaging of the lung will soon be recognized as equivalent to the high-resolution technique in chest CT imaging. In this article, the difficulties in MR imaging posed by lung morphology and its physiological motion are briefly introduced. Then, fast MR imaging techniques to overcome the problems of lung imaging and recent applications of the fast MR techniques including pulmonary perfusion and ventilation imaging are discussed. Fast MR imaging opens a new exciting window to multi-functional MR imaging of the lung. We believe that fast MR functional imaging will play an important role in the assessment of pulmonary function and disease process.

Humans↗
PubMed1999

Differential effects of mental stress on plasma homovanillic acid in schizophrenia and normal controls.

We previously reported that mental stress by Kraepelin's arithmetic test decreases plasma homovanillic acid (pHVA) levels in psychiatrically normal healthy human subjects. The present study was undertaken to determine whether this pattern of changes in pHVA concentrations resulting from mental stress is altered in patients with schizophrenia. Fourteen male patients with schizophrenia including those under ongoing neuroleptic treatment and 14 normal male volunteers participated in the study. Following overnight fast and restricted physical activity, the subjects performed Kraepelin's arithmetic test for 30 minutes. Plasma samples were collected immediately before and after the test for measurement of pHVA levels. A significant diagnosis by Kraepelin's test effect was observed due to a decrease in pHVA levels by the Kraepelin test in control subjects but not in patients with schizophrenia. Changes in pHVA levels during the Kraepelin test positively correlated with pre-test pHVA levels in control subjects, while this correlation was not observed in patients with schizophrenia. These results may be further support for the presence of a dopamine-dependent restitutive system in the brain. The absence of response of pHVA levels to mental stress in patients with schizophrenia may indicate that the dopamine restitutive system in these patients is disrupted or already down-regulated, as previously predicted.

Adolescent↗
PubMed1999

Identification of chick rax/rx genes with overlapping patterns of expression during early eye and brain development.

We have isolated chick rax/rx cDNAs, cRaxL (chick Rax/Rx-like) and cRax, (chick Rax) and examined their expression patterns during early eye and brain development. The cRaxL cDNA encodes a 228 amino acid protein that is most closely related to the zebrafish Rx1 and Rx2. The cRax cDNA encodes a 317 amino acid protein, which shares higher homology with the Xenopus Rx. In addition to the homeodomain, the octapeptide and paired tail domains are conserved between the cRax and other vertebrate Rax/Rx, while cRaxL lacks the octapeptide containing N-terminal region which is conserved among all other members of the rax/rx gene family identified so far. The chick rax/rx genes are expressed in overlapping domains in the anterior neural ectoderm which corresponds to the forebrain and retina field, and later in the optic vesicle. cRax mRNA can be detected earlier than cRaxL prior to the formation of the notochord and its expression domain appears broader than that of cRaxL.

Animals↗
PubMed1999

Association of 72-kDa heat shock protein expression with adaptation to aspirin in rat gastric mucosa.

It is well documented that gastric mucosa can increase its resistance to mucosal damage caused by aspirin during repeated long-term administration of aspirin. However, the underlying mechanism of this adaptation is not well established. In the present study, we investigated the effect of long-term (chronic) administration of aspirin on expression of heat shock proteins (HSPs), which are known as endogenous cytoprotectants, in rat gastric mucosa. Rats were administered aspirin (100 mg/kg) daily for up to 20 days. After various periods of aspirin administration, a high dose of aspirin (250 mg/kg) was administered, and the mucosal damage was assessed. Expression of heat shock proteins (HSPs) in gastric mucosa was evaluated by Western blot. Intracellular localization of each HSP was studied immunohistochemically. Prostaglandin E2 (PGE2) and leukotriene B4 (LTB4) levels were also investigated. Long-term aspirin administration resulted in development of resistance to aspirin-induced mucosal damage, and the increase of HSP72 expression correlated with mucosal resistance to aspirin. No significant increase was observed in HSP60 and HSP90 levels. Immunohistochemical study showed an increase of HSP72 in the cytoplasm of mucosal surface cells. The PGE2 level was suppressed and no change in the level of LTB4 was observed. It is possible that HSP72 could play important roles in gastric mucosal adaptation when the PGE2 level is suppressed by NSAIDs.

Adaptation, Physiological↗
PubMed1999

The gene encoding tobacco gibberellin 3beta-hydroxylase is expressed at the site of GA action during stem elongation and flower organ development.

Gibberellin 3beta-hydroxylase catalyzes the final step in the biosynthetic pathway leading to the plant hormone gibberellin (GA) and, therefore, the in vivo localization of this enzyme should give a direct indication of the site of synthesis of bioactive GAs in plants. We have isolated a cDNA clone, Nty (Nicotiana tabacum GA 3beta-hydroxylase), which encodes a putative GA 3beta-hydroxylase, by RT-PCR using RNA from tobacco shoot apices. Functional analysis, using an NTY protein expressed in Escherichia coli, revealed that Nty encoded an active GA 3beta-hydroxylase. A high expression level of Nty was observed in shoot apices, flowers, roots, young internodes but not in leaves or seeds. We performed more detailed expression analyses using in situ hybridization and histochemical analyses of the GUS activity in transgenic tobacco plants carrying an Nty promoter:GUS fusion gene. These studies revealed that expression of Nty was restricted to specific regions, including actively dividing and elongating cells in the various organs; rib meristem and elongation zones of shoot apices, tapetum and pollen grains in developing anthers and root tips, which are consistent with the sites of GA action. It is proposed that GA actions depend on the modulation of endogenous bioactive GA levels through the regulation of GA 3beta-hydroxylase expression in situ.

Amino Acid Sequence↗
PubMed1999

Hypertension and insulin resistance: role of peroxisome proliferator-activated receptor gamma.

1. Insulin resistance has been highlighted as a common causal factor for hypertension, hyperlipidaemia, diabetes mellitus and obesity, all of which are recognized to occur simultaneously, and a distinct clinical entity is defined as 'multiple risk factor syndrome'. 2. Recently, a new class of antidiabetic agents, thiazolidinediones (TZD) has been developed and has been shown to improve insulin resistance by binding and activating a nuclear receptor, peroxisome proliferator-activated receptor (PPAR) gamma. 3. cDNA of rat PPAR gamma 1 and gamma 2 were cloned and gene regulation of PPAR gamma in rat mature adipocytes was examined. Hydrogen peroxide, an oxygen radical, which is recognized to be the common intracellular signal for multiple risk factors, potently down-regulated PPAR gamma mRNA expression in rat mature adipocytes. 4. Tumour necrosis factor (TNF)-alpha, which is considered to play a role in obesity-induced non-insulin-dependent diabetes mellitus and to augment oxidative stress, also suppressed PPAR gamma expression. 5. Thiazolidinediones dose-dependently recovered TNF-alpha-induced down-regulation of PPAR gamma mRNA expression. 6. The modulation of PPAR gamma expression by TZD can be one mechanism for the improvement of insulin resistance by TZD. 7. Vascular tone and remodelling are controlled by several vasoactive autocrine/paracrine factors produced by endothelial cells in response to several vascular injury stimuli, including hypertension. The PPAR gamma gene transcript was detected in cultured endothelial cells. 8. The administration of TZD stimulated the endothelial secretion of type-C natriuretic peptide, which is one of the natriuretic peptide family and is demonstrated by us to act as a novel endothelium-derived relaxing peptide. 9. Concomitantly, TZD significantly suppressed the secretion of endothelin, a potent endothelium-derived vasoconstricting peptide. 10. Thiazolidinediones can affect vascular tone and growth by modulating the production of endothelium-derived vasoactive substances to influence occurrence and progression of hypertension and atherosclerosis.

Adipose Tissue↗
PubMed1999

New members of uncoupling protein family implicated in energy metabolism.

1. The regulation of energy metabolism involves food intake and energy expenditure. Mitochondrial uncoupling proteins (UCP) are implicated in energy expenditure. 2. cDNA of a homologue of UCP highly expressed in rat skeletal muscle, UCP-3, is isolated and sequenced. Rat UCP-2 cDNA is also isolated and sequenced. 3. Rat UCP-3 cDNA probe hybridized two bands, a major band at 2.5 kb and a minor band at 2.8 kb in rat tissues. The mRNA was expressed at the highest level in the skeletal muscle, and moderately in the interscapular brown adipose tissue (BAT). Only weak signals were detected in the epididymal white adipose tissue (WAT) and the heart. Rat UCP-2 cDNA probe hybridized a 1.7 kb band detected widely in the whole body, especially abundant in the lung and the spleen. In contrast to the UCP-3 gene expression, the UCP-2 gene expression was expressed at substantial levels in the WAT and only at slight levels in the skeletal muscle and BAT. 4. The UCP-3 gene expression is augmented two-fold in the gastrocnemius muscle from rats fed a high-fat diet (P < 0.05). The UCP-3 mRNA levels remained unchanged in the interscapular BAT, and epididymal WAT. The levels of the UCP-2 gene expression are augmented significantly in the epididymal WAT (1.6-fold; P < 0.05), while no significant increase is observed in the gastrocnemius muscle and interscapular BAT.

Adipose Tissue↗
PubMed1999

Re-entrainment of circadian rhythm of plasma melatonin on an 8-h eastward flight.

To estimate the process of re-entrainment we measured the melatonin rhythm on an eastward flight. After the baseline study, 24-hour blood sampling of six male subjects was done on the first and fifth days. During the daytime the subjects were exposed to natural zeitgeber outdoors every day except the blood sampling day. They were analyzed with an illuminometer when under the bright light condition. Four of the six subjects showed orthodromic re-entrainment, another subject showed antidromic re-entrainment, and the other subject kept the baseline pattern of plasma melatonin. The rate of re-entrainment in orthodromic re-entrainment was about 55 min per day. Measuring the circadian rhythm of plasma melatonin has clarified the interindividual re-entrainment difference.

Adaptation, Physiological↗
PubMed1999

Retroperitoneal bronchogenic cyst: report of a case and literature review.

A large cystic mass was found in the subdiaphragmatic region of a 46-year-old woman who had complained of continuous pain in the left flank . The cyst was located in the retroperitoneum just below the diaphragm and was adhered to the diaphragmatic skeletal muscle and abdominal aorta, but was separate from the spleen, pancreas, left adrenal gland and left kidney. The surgically resected cyst measured 8 x 8 x 7 cm and was filled with protein-rich fluid, which contained amylase and embryonal proteins such as carcinoembryonic antigen, CA125 and CA19-9. Histologically, the cyst wall was composed of a fibrovascular connective tissue containing thin smooth muscle layers and mucus-secreting glands and was lined by a ciliated pseudostratified or tall columnar epithelium without dysplastic changes. Thus, a diagnosis of bronchogenic cyst, which is usually discovered in the posterior part of the mediastinum, was made. A rare case of bronchogenic cyst and a literature review is presented.

Biomarkers↗
PubMed1999

Combined small and transitional cell carcinoma of the urinary bladder with CA19-9 production.

It is well known that extrapulmonary small cell carcinoma, which exhibits morphological features similar to those observed in the lung, occurs in various organs. Clinically, most cases manifest aggressive biological behavior. A case of small cell carcinoma of the urinary bladder producing a high level of serum carbohydrate antigen (CA) 19-9, in which expression was confirmed in cancer cells of small as well as transitional cell carcinoma in the same tumor mass by immunostaining is reported. This paper documents combined small and transitional cell carcinoma of the urinary bladder with CA19-9 production, although it has already been reported that adenocarcinoma or transitional cell carcinoma in various organs frequently expresses CA19-9. Observations suggest that the histogenesis of some cases of combined small and transitional cell carcinoma in the urinary bladder may be the same, as both can produce CA19-9.

Aged↗
PubMed1999

Intracellular localization of HSP73 and HSP90 in rat kidneys with acute lysosomal thesaurismosis.

We previously reported that HSP73 and HSP90, major chaperone proteins, accumulated within lysosomes of proximal tubular epithelial cells in rat kidneys with acute gentamicin nephropathy. In this study, we observed serial localization of HSP73 and HSP90 in rat kidneys with acute lysosomal thesaurismosis. Sprague-Dawley rats received poly-D-glutamic acid (PDGA) (250 mg/kg per day) for 3 days, and developed acute lysosomal thesaurismosis of proximal tubular epithelial cells. The intracellular localization of HSP73 and HSP90 was examined by electron microscopy. We also compared the results with those of a non-chaperone protein, a renal isoform of argininosuccinate synthetase, which is an abundant enzyme in proximal tubular epithelial cells. After the PDGA exposure, HSP73 and HSP90 accumulated within enlarged lysosomes of proximal tubular epithelial cells. These accumulations started to appear from day 4 after the first PDGA administration, enlarged in size until day 14, and continued until day 19. Argininosuccinate synthetase also accumulated within the lysosomes, but the magnitude of this lysosomal accumulation was less than those of HSP73 and HSP90. Our findings demonstrated that HSP73 and HSP90 chaperone proteins specifically accumulated within lysosomes of proximal tubular epithelial cells during the course of PDGA-induced acute lysosomal thesaurismosis.

Acetylglucosaminidase↗