Search PubMed⌕ Search

Biomedical subjects

H Honda

Publications and source records attributed to H Honda.

At least 91 records · Page 5Linked to original sources
PubMed2000

Evaluation of autonomic nervous function during upper gastrointestinal endoscopy using heart rate variability.

To investigate autonomic nervous function during upper gastrointestinal endoscopy, we analyzed R-R interval variability from electrocardiograms obtained during endoscopy. Holter electrocardiogram recordings were made before and after premedication, and during endoscopy. Time- and frequency-domain analyses of heart rate variability were performed in 54 subjects premedicated with scopolamine butylbromide (SB group) and in 66 subjects premedicated with glucagon (G group). To determine the effect of autonomic imbalance on arrhythmia generation during endoscopy, subjects with arrhythmias (A group) were compared with subjects without arrhythmias (N group). In the SB group, high frequency spectral power (HF power; 0.15 to 0.40 Hz), which reflects parasympathetic activity, decreased significantly after premedication, and decreased further during endoscopy (P < 0.01). Moreover, HF power before premedication or during endoscopy in the A group was significantly lower than that in the N group (P < 0.01). This study suggests that the measurement of HF power prior to endoscopy can identify subjects with reduced HF power. This should allow the prevention of cardiovascular complications related to premedication and endoscope insertion.

Adult↗
PubMed2000

Management of nodular goiters and their operative indications.

It remains controversial whether or not nodular goiters should be treated surgically or conservatively. This report reviews our 9-year experience of treating nodular goiters in 334 patients, 44 of whom underwent surgery, and compares the methods of treatment employed from 1990 to 1999 with those employed from 1971 to 1989 when 171 operations were carried out. In accordance with diagnoses made using fine-needle aspiration biopsy (FNAB) and ultrasonography, patients were treated as follows. Those with cysts were given percutaneous ethanol injection therapy (PEIT), and those with solid tumors underwent surgery if cancer of >class 3 was suspected or if the tumors were >3 cm. Consequently, 44 patients with solid tumors underwent surgery and 72 with cysts were treated by PEIT. The number of operations performed annually decreased to half of the pre-1990 figure. During the follow-up of those patients who did not undergo surgery, four with solid tumors and two with cysts later required surgery due to suspected carcinoma of >class 3 in 3 patients or as a result of personal choice in 3 patients. The growth of solid tumors was not able to be measured in most cases. These results indicate that the number of operations performed for nodular goiters can be reduced by PEIT. An accurate cytological diagnosis supports this therapeutic strategy.

Biopsy, Needle↗
PubMed2000

Changes in vascular reactivity induced by acute hyperthyroidism in isolated rat aortae.

Hyperthyroidism was induced by subcutaneous injections of L-thyroxine (T(4)) (500 mg/kg/day) for 3 days in order to study whether adrenergic and muscarinic receptor-mediated vascular responses alter at an early stage of the disease. T(4) treatment was sufficient to induce a significant degree of thyroid weight loss, tachycardia, cardiac hypertrophy, and an elevation in serum T(4) levels. The tension of aortic ring preparations isolated from rats was measured isometrically to investigate the influence of acute hyperthyroidism. The contractions induced by norepinephrine (NE) were significantly suppressed in aortic rings from rats treated with T(4) compared with control rats. N(G)-nitro-L-arginine (L-NOARG), an inhibitor of nitric oxide synthase (NOS), significantly enhanced NE-induced contraction in aortic rings from both control and T(4)-treated rats, and the enhancement was greater in rats treated with T(4) than control rats. The relaxations induced by either acetylcholine (ACh) or sodium nitroprusside (SNP) were also significantly enhanced by T(4) treatment. L-NOARG abolished the relaxation induced by ACh in aortic rings from both control and T(4)-treated rats. L-NOARG shifted SNP-induced relaxation curves of aortic rings from those of control rats to the left, but not with rats treated with T(4). T(4) treatment showed no influence on the amount of endothelial NOS (eNOS) protein. These results suggest that vascular responses alter at an early stage of hyperthyroidism and that it may be due to a modification in the NO system which is independent from the amount of eNOS protein.

Acetylcholine↗
PubMed2000

Chronic fatigue syndrome in childhood.

Chronic fatigue occurring in previously healthy children and adolescents is one of the most vexing problems encountered by pediatric practitioners. We report three cases, 11, 12 and 13-year-old children, with chronic fatigue syndrome (CFS). They initially developed a low grade fever and generalized fatigue, followed by sleep disturbance and psychosomatic symptoms, and their performance ability deteriorated. They were diagnosed as having CFS on the basis of criteria. To investigate the brain function in CFS patients, we examined the regional cerebral blood flow by single-photon emission-computed tomography (SPECT) with 111 MBq [123I]-iodoamphetamine (123I-IMP) or xenon-computed tomography (Xe-CT), and brain metabolic levels by MR spectroscopy (MRS). Blood flow, expressed as the corticocerebellar ratio (CCR), in the left temporal and occipital lobes was markedly lower in cases 2 and 3 than that in healthy subjects reported by another investigator. In case 1, however, blood flow in the left basal ganglia and thalamus was markedly higher than in healthy subjects. The MR spectroscopy (MRS) study revealed remarkable elevation of the choline/creatine ratio in the patients with CFS. None of our patients exhibited evidence of focal structural abnormalities on MRI. These findings suggest that the various clinical symptoms in CFS patients may be closely related to an abnormal brain function.

Adolescent↗
PubMed2000

Fuzzy control of bioprocess in Japan.

Process control of bioprocess has been carried out by the judgment of the experts, who are the skilled operators and have lots of experiences for the control of the process. In almost all cases, those experiences are described linguistic IF-THEN rules. Fussy inference is one of the powerful tools to incorporate the linguistic rules to the computer for process control. Fuzzy control are divided into two types; one is the direct fuzzy control of process variables such as sugar feed rate in fed-batch culture and fermentation temperature in batch operation. The other is the indirect control of bioprocess, in which at first the phase recognition is carried out by fuzzy inference and the control strategies constructed in each phase are used for the control of process variables. In Japan, the fuzzy control has already been applied to practical industrial productions, such as pravastatin precursor, vitamin B2, and Japanese sake mashing process. In this review, these industrial approaches of fuzzy control are introduced.

Alcoholic Beverages↗
PubMed2000

Fuzzy control of bioprocess.

Bioprocesses have been operated according to the judgment of experts who are skilled operators and have long experience. In almost all cases, these experiences are described by linguistic IF-THEN rules. Fuzzy inference is one of the powerful tools to incorporate linguistic rules into computational algorithms for application to process control. Fuzzy control is categorized into two types: the direct fuzzy control of process variables such as sugar feed rate in fed-batch culture and broth temperature in batch operation, and the indirect control of bioprocesses in which the phase recognition is first done by fuzzy inference using process variables such as DO, sugar concentration, pH and so on and then the control strategies having been constructed in each phase are used for the process operation. Fuzzy control has already been applied to practical industrial processes, such as production of a pravastatin precursor and vitamin B2, and the Japanese sake mashing process. In this review, these industrial practices of fuzzy control are introduced.

Journal Article↗
PubMed2000

Development of chitosan-magnetite aggregates containing Nitrosomonas europaea cells for nitrification enhancement.

A cell suspension of the nitrifying bacterium Nitrosomonas europaea obtained after 96-h cultivation was subjected to magnetic separation using chitosan-conjugated magnetite particles (chitosan-magnetite), which have the ability to form aggregates with microbial cells. An equilibrium condition was obtained at room temperature after 30 min and over 90% of the cells were recovered when the chitosan-magnetite concentration was 200 mg/l. The relationship between the cell concentration in the supernatant in equilibrium and the number of cells adsorbed per 1g chitosan-magnetite was expressed by a Freundlich-type adsorption equation. A high nitrifying bacterium activity yield was obtained with a chitosan-magnetite concentration between 100 and 200 mg/l. Repeated batch culture resulted in more N. europaea cells accumulating on the aggregates and as a consequence their nitrification activity improved further. The chitosan-magnetite/cell aggregates were recovered and employed to remove ammonia from artificial wastewater together with PVA-alginate gel beads containing the denitrifying bacterium Paracoccus denitrificans. A higher ammonia removal rate was achieved under aerobic conditions in comparison with that obtained when N. europaea and P. denitrificans were coimmobilized in PVA-alginate gel beads.

Journal Article↗
PubMed2000

Differentiation of wing epidermal scale cells in a butterfly under the lateral inhibition model--appearance of large cells in a polygonal pattern.

Cellular pattern formations of some epithelia are believed to be governed by the direct lateral inhibition rule of cell differentiation. That is, initially equivalent cells are all competent to differentiate, but once a cell has differentiated, the cell inhibits its immediate neighbors from following this pathway. Such a differentiation repeats until all non-inhibited cells have differentiated. The cellular polygonal patterns can be characterized by the numbers of undifferentiated cells and differentiated ones. When the differentiated cells become large in size, the polygonal pattern is deformed since more cells are needed to enclose the large cell. An actual example of such a cellular pattern was examined. The pupal wing epidermis of a butterfly Pieris rapae shows a transition of the equivalent-size cell pattern to the pattern involving large cells. The process of the transition was analyzed by using the method of weighted Voronoi tessellation that is useful for treatment of irregularly sized polygons. The analysis supported that the pattern transition of the early stage of the pupal wing epidermis is governed by the lateral inhibition rule. The differentiation takes place in order of largeness, but not smallness, of the apical polygonal area in the differentiating region of the pupal wing.

Animals↗
PubMed2000

Survey of mariner-like elements in the housefly, Musca domestica.

The presence of mariner-like elements in four strains of the housefly, Musca domestica, was surveyed by PCR. Using the inverted terminal repeat (ITR) sequences of the Mos 1 element as primers, DNAs were successfully amplified from all strains of the housefly. Southern blot analysis indicated that these amplified DNAs were repetitive sequences in the genome of M. domestica. Sequence analyses of cloned PCR products showed that they were 45% identical to the Mos 1 element. These fragments appeared to be nonfunctional, because they contained no intact open reading frame (ORF) capable of encoding transposase. We conclude that these DNAs are degraded mariner-like elements (MLEs) in M. domestica. Because these endogenous MLEs in M. domestica do not encode any functional proteins, they probably would not affect the behavior of mariner-based vectors if such were introduced into this species as transformation vectors.

Animals↗
PubMed2000

Synthesizing oligomers from monomeric nucleotides in simulated hydrothermal environments.

Dimers and trimers of adenosine monophosphate (AMP) were synthesized from AMP in environments simulating hot vents on the sea floor of the primitive Earth. The simulated environments were made in the flow reactor, in which an aqueous solution of reactants was circulated from the hot to the cold region repeatedly. The oligomerization proceeded most significantly when the hot reaction solution at about 110 degrees C was abruptly ejected into the cold environment maintained at about 0 degree C.

Adenine Nucleotides↗
PubMed2000

Hydrothermal circulation of seawater through hot vents and contribution of interface chemistry to prebiotic synthesis.

Synthesizing oligopeptides from glycine and alanine in a flow reactor, which stimulates constant hydrothermal circulation of seawater through hot vents on the primitive Earth, demonstrated that an exponential growth of the products is possible. The initial rapid growth of the product is a consequence of using the products formed in one cycle as the starting materials for the cycle of synthesis.

Alanine↗
PubMed2000

Is autonomic dysfunction a necessary condition for chronic peptic ulcer formation?

BACKGROUND: The relationship between 1/f fluctuation of the heart rate variability and Helicobacter pylori infection was evaluated, in order to clarify whether autonomic nervous dysfunction is a necessary condition for chronic peptic ulcer formation. METHODS: The subjects were 11 patients with recurrent chronic peptic ulcer and 20 age-matched normal subjects. Holter ECGs were recorded over 24 h, and the 1/f(-x) fluctuation of the heart rate was computed. The 1/f(-x) fluctuation of the heart rate is a novel index of autonomic function that has been shown to reflect a patient's pleasant mood. For 1/f(-x) fluctuation, the slope of the regression line (-x) was determined and cosine fitting of the absolute slope of the regression line over a 24-h period was performed. RESULTS: For the normal group, the absolute slope of the regression line during daytime and night-time were 0.53 +/- 0.16 and 1.05 +/- 0.18, respectively. For the peptic ulcer group, the corresponding values during daytime and night-time were 0.94 +/- 0.15 and 1.84 +/- 0.18, respectively. The mean value of the cosine curve was 0.76 +/- 0.23 in the normal group and 1.12 +/- 0.25 in the peptic ulcer group. Thus, these values were significantly higher for the latter group than for the former group (P<0.05). No statistically significant difference in H. pylori infection between the two groups was observed. CONCLUSIONS: Autonomic nervous dysfunction as well as H. pylori infection appears to be a necessary condition for chronic peptic ulcer formation.

Aged↗
PubMed2000

Esophageal pressure and apnea hypopnea index in sleep-disordered breathing.

Severity of negative esophageal pressure (Pes) and apnea hypopnea index (AHI) were investigated in six cases of upper airway resistance syndrome (UARS) and 11 cases of obstructive sleep apnea syndrome (OSAS). The severity of negative Pes was represented by the highest peak (Pes Max) and the number of increased episodes (more than 13.5 cmH2O) per h (NPesI13.5). There was no significant correlation between Pes indices and AHI. Pes Max and NPesI13.5 were not different among severe OSAS (AHI > 30), mild OSAS (AHI < 30) and UARS. Apnea hypopnea index failed to represent the severity of negative Pes, which is an important aspect of the pathophysiology of sleep-disordered breathing.

Adult↗
PubMed2000

Glycine prevents apoptosis of rat sinusoidal endothelial cells caused by deprivation of vascular endothelial growth factor.

Apoptosis of sinusoidal endothelial cells (SECs) is one of the initial events in the development of ischemia-reperfusion injury of the liver. Glycine has been shown to diminish ischemia-reperfusion injury in the liver and improve graft survival in the rat liver transplantation model. Here, we investigated the effect of glycine on apoptosis of primary cultured rat SECs induced by vascular endothelial growth factor (VEGF) deprivation. Isolated rat SECs were cultured in EBM-2 medium supplemented with 10% fetal bovine serum (FBS) and growth factors including 20 ng/mL VEGF for 3 days. SECs at 3 days of culture showed spindle-like shapes; however, cells started shrinking and detaching from dishes by VEGF deprivation. Apoptosis was detected by terminal deoxynucleotidyl transferase (TdT)-mediated d-uridine triphosphate (dUTP)-biotin nick end labeling (TUNEL) staining in these conditions. Control SECs contained only a few percent of TUNEL-positive cells; however, they started increasing 4 hours after VEGF deprivation, and the percentage of TUNEL-positive cells reached about 50% at 8 hours and almost 100% at 16 hours after VEGF deprivation. Interestingly, this increase in TUNEL-positive cells after VEGF deprivation was prevented significantly when glycine (1-10 mmol/L) was added to the medium, the levels being around 60% of VEGF deprivation without glycine. Furthermore, strychnine (1 micromol/L), a glycine receptor antagonist, inhibited this effect of glycine, suggesting the possible involvement of the glycine receptor/chloride channel in the mechanism. Moreover, Bcl-2 protein levels in SECs were decreased 8 hours after VEGF deprivation, which was prevented almost completely by glycine. It is concluded that glycine prevents apoptosis of primary cultured SECs under VEGF deprivation.

Animals↗
PubMed2000

Primary bone tumors of the femur presenting with spinal symptoms: a report of two cases and review of the literature.

Two case reports of femoral bone lesions simulating lumbar spinal disease are presented. Physical examination and case history were strongly suggestive of lumbar spinal pathology. In case 1, surgical resection of a venous hemangioma in the lumbar epidural space was performed but did not relieve pain. In case 2, conservative treatments for a protruded disk were performed for 3 months before an accurate diagnosis was made. After correct diagnoses were made, excision of the femoral tumors brought rapid relief of all abnormal findings in both cases. Compared with other causes of sciatica, femoral bone tumors are rare. However, careful attention should be paid to rule out these lesions if the diagnosis of a lumbar spinal disease is uncertain. Bone scintigraphy seems to be a sensitive diagnostic method to detect extraspinal osseous lesions.

Adult↗
PubMed2000

Observation of spatial asymmetry of THz oscillating electron plasma wave in a laser wakefield

The asymmetric spatial distribution of electron density perturbation is observed by using a frequency-domain interferometry technique. The wake amplitude of the outside bump is enhanced by the elliptical distribution of the pump laser pulse. This asymmetry can be explained with a two-dimensional analytical model expanded from cylindrically symmetric linear theory.

Journal Article↗
PubMed2000

Real-time automated PCR for early diagnosis and monitoring of cytomegalovirus infection after bone marrow transplantation.

The purpose of this study was to assess the usefulness of real-time automated PCR as a quantitative, highly reproducible, and sensitive method to detect cytomegalovirus (CMV) DNA in blood specimens. Intra- and interassay precision rates were 0.89% (small number of copies [L]), 1.43% (middle number of copies [M]), and 1.12% (high number of copies [H]), and 4.46% (L), 1.51% (M), and 2.28% (H), respectively. The linearity of this assay was obtained between 10 and 10(7) copies/well, with a minimum detection limit of 20 copies/well. Specimens from 55 of 70 healthy subjects were found to be positive for CMV antibody, but CMV DNA was not detected in any of them. In the qualitative assessment of each specimen, the results of the CMV antigenemia assay and those of the real-time PCR assay agreed in 80% (plasma specimens), 79% (all nucleated cells), and 86% (blood) of the cases examined. For eight patients diagnosed as having CMV infection or disease, no sample was positive in the antigenemia assay earlier than in the real-time PCR assay. Furthermore, the results of this assay could be obtained within 8 h. We concluded that the real-time PCR assay is useful for rapid diagnosis of CMV infection and monitoring of clinical courses.

Adolescent↗