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Biomedical subjects

K Ito

Publications and source records attributed to K Ito.

At least 109 records · Page 6Linked to original sources
PubMed2003

Importance of transmembrane segments in Escherichia coli SecY.

To assess the functional importance of the transmembrane regions of SecY, we constructed a series of SecY variants, in which the six central residues of each transmembrane segment were replaced by amino acid residues from either transmembrane segment 3 or 4 of LacY. The SecY function, as assessed by the ability to complement cold-sensitive secYmutants with respect to their growth and translocase defects, was eliminated by the alterations in transmembrane segments 2, 3, 4, 7, 9 and 10. Among them, those in segments 3 and 4 had especially severe effects. In contrast, transmembrane segments 1, 5, 6, and 8 were more tolerant to the sequence alterations. The purified protein with an altered transmembrane segment 6 retained, in large measure, the ability to support SecA-dependent preprotein translocation in vitro. These results will help us to further understand how the SecYEG protein translocation channel functions.

Amino Acid Sequence↗
PubMed2003

Reliability of the mechanomyogram detected with an accelerometer during voluntary contractions.

The accelerometer is used for mechanomyogram (MMG) recordings of muscle contractions. Although the mechanical characteristics of other MMG transducers have been determined with reference to the accelerometer, mechanical aspects of the accelerometer itself, including the weight of the transducer, have not been verified. This study was designed to reinvestigate the mechanical variable of the MMG signal detected with an accelerometer, with reference to a laser distance sensor (LDS), and then to clarify the influence of the accelerometer weight on the MMG recording during muscle contractions. The study was performed during mechanical sinusoidal vibrations and during voluntary contractions of the quadriceps muscle. Maximum differences in the amplitude spectral density functions between the LDS signal and the double integral of the accelerometer signal were approximately 4 microm. The results verified that the MMG signal from the accelerometer accurately reflected the acceleration of body surface vibration. However, the MMG signal was gradually distorted when weight was added to the accelerometer: the addition of 4.0 g (total 6.0 g, including 2.0 g of accelerometer) substantially attenuated the MMG signal. The results suggest that the appropriate weight for the accelerometer should be less than 5.0 g for measurements of the quadriceps muscle and indicate that the transducer weight must be taken into account for accurate measurement of muscles of different sizes.

Adult↗
PubMed2003

Interactions of HLA-DRB4 and CTLA-4 genes influence thyroid function in Hashimoto's thyroiditis in Japanese population.

Hashimoto's thyroiditis (HT) is an autoimmune disease of the thyroid gland, and like many other autoimmune diseases, it is associated with the HLA and CTLA-4 gene. We have examined the distribution of the HLA DRB4*0101 allele and a CTLA-4 exon 1 A/G polymorphism in Japanese HT patients and controls and investigated possible interactions of these genes with thyroid function. Seventy Japanese HT patients and 105 controls were included in this study. HT was diagnosed on the basis of positivity for thyroid peroxidase (TPO) autoantibodies and the presence of a palpable diffuse goiter. Genotyping was performed by polymerase chain reaction (PCR)-based methods. CTLA-4-GG or -AG was more prevalent in the patients, and the odds ratio for the G allele was 4.95. The frequency of DRB4*0101-positive individuals was significantly higher in HT (odds ratio=2.17). The TSH values of HT patients at the time of diagnosis were compared to CTLA-4 genotype and HLA-DRB4*0101 positivity. They were slightly higher in the CTLA-4-AG group than in the -GG group and significantly higher in the HLA-DRB4*0101-positive group than in the -negative group (p<0.01). When the TSH values were compared in 4 groups based on positivity or negativity for HLA-DRB4*0101 and CTLA-4 GG or AG, they were found to be significantly higher in the CTLA-4-AG and HLA-DRB4*0101-positive group than in the 3 other groups (F=5.75, 3 degrees of freedom, p<0.01). These findings suggest that the interaction between the HLA-DRB4 and CTLA-4 genes determines the thyroid function of TPO-positive goitrous Japanese HT patients.

Adenine↗
PubMed2003

An in vitro investigation of the acetabular labral seal in hip joint mechanics.

Labrum pathology may contribute to early joint degeneration through the alteration of load transfer between, and the stresses within, the cartilage layers of the hip. We hypothesize that the labrum seals the hip joint, creating a hydrostatic fluid pressure in the intra-articular space, and limiting the rate of cartilage layer consolidation. The overall cartilage creep consolidation of six human hip joints was measured during the application of a constant load of 0.75 times bodyweight, or a cyclic sinusoidal load of 0.75+/-0.25 times bodyweight, before and after total labrum resection. The fluid pressure within the acetabular was measured. Following labrum resection, the initial consolidation rate was 22% greater (p=0.02) and the final consolidation displacement was 21% greater (p=0.02). There was no significant difference in the final consolidation rate. Loading type (constant vs. cyclic) had no significant effect on the measured consolidation behaviour. Fluid pressurisation was observed in three of the six hips. The average pressures measured were: for constant loading, 541+/-61kPa in the intact joint and 216+/-165kPa following labrum resection, for cyclic loading, 550+/-56kPa in the intact joint and 195+/-145kPa following labrum resection. The trends observed in this experiment support the predictions of previous finite element analyses. Hydrostatic fluid pressurisation within the intra-articular space is greater with the labrum than without, which may enhance joint lubrication. Cartilage consolidation is quicker without the labrum than with, as the labrum adds an extra resistance to the flow path for interstitial fluid expression. However, both sealing mechanisms are dependent on the fit of the labrum against the femoral head.

Acetabulum↗
PubMed2003

Neural crest stem cell and cardiac endothelium defects in the TrkC null mouse.

TrkC null mice have multiple cardiac malformations. Since neural crest cells participate in cardiac outflow tract septation, the aim of this study was to determine at the cellular level the putative neural crest defect. We have identified three types of progenitor cells: stem cells that undergo self-renewal and can generate many cell types, cells that are restricted in their developmental potentials, and cells that are committed to the smooth muscle cell lineage. In TrkC null mice, there is a greater than 50% decrease in stem cell numbers and an equivalent increase in fate-restricted cells. The outflow tract wall is thickened and the endothelial tube is disorganized. We conclude that deletion of the TrkC gene causes precocious fate restrictions of the neural crest stem cell and a defect of the outflow tract endothelium, both of which may contribute to the outflow tract malformations that occur in TrkC null mice.

Animals↗
PubMed2003

An experimental two degrees-of-freedom actuated external fixator for in vivo investigation of fracture healing.

A novel two degrees-of-freedom external fixator that can accurately control interfragmentary mechanical conditions over an ovine tibial osteotomy is presented. The device can apply either axial or torsional motion, to investigate mechano-transduction mechanisms in fracture healing. The device was bench-tested over a range of gap stiffnesses, for its ability to apply pure axial or torsional motions, control interfragmentary strain magnitudes and to measure stiffness over the gap. The experiments reveal very little cross-coupling between axial and torsional displacements, although some transverse displacement occurs for both degrees-of-freedom. The mean interfragmentary strain can also be accurately controlled, but with some variation over the gap (due to coupled transverse displacement error). Interfragmentary stiffness measurements are accurate up to gap stiffnesses corresponding to bony bridging. This characterisation study has shown that the system is adequate to control and measure the mechanical conditions in a fracture healing experiment.

Animals↗
PubMed2003

p53 and PTEN/MMAC1 mutational analysis of the small-intestinal cancer.

A 66-year-old female, suffering from small-intestinal cancer underwent resection of the small intestine. Genome DNAs were extracted from the patient's blood and small-intestinal cancer and were subjected to a polymerase chain reaction-single strand conformation polymorphism and nucleotide sequence analysis for exons of the p53 and PTEN/MMAC1 genes to search for any mutations. The sequence analysis revealed a point mutation of the p53 codon 93 in the cancer DNA; however, no mutation of the PTEN/MMAC1 gene was observed in either the blood or cancer DNA. The p53 mutation, therefore, seems to be related to tumour progression of small-intestinal cancer; however, no relationship was found between the PTEN/MMAC1 gene and the small-intestinal cancer.

Aged↗
PubMed2003

Modeling and CFD prediction for diffusion and adsorption within room with various adsorption isotherms.

This paper presents physical models that are used for analyzing numerically the transportation of volatile organic compounds (VOCs) from building materials in a room. The models are based on fundamental physicochemical principles of their diffusion and adsorption/desorption (hereafter simply sorption) both in building materials and in room air. The performance of the proposed physical models is examined numerically in a test room with a technique supported by computational fluid dynamics (CFD). Two building materials are used in this study. One is a VOC emitting material for which the emission rate is mainly controlled by the internal diffusion of the material. The other is an adsorptive material that has no VOC source. It affects the room air concentration of VOCs with its sorption process. The floor is covered with an emission material made of polypropylene styrene-butadiene rubber (SBR). An adsorbent material made of coal-based activated carbon is spread over the sidewalls. The results of numerical prediction show that the physical models and their numerical simulations explain well the mechanism of the transportation of VOCs in a room.

Adsorption↗
PubMed2003

Analysis of visitation frequency through particle tracking method based on LES and model experiment.

As ventilation efficiency in a room is not always uniformly distributed, an index for measuring ventilation efficiency at a concerned point or in a concerned local domain is required. Local ventilation efficiency is often represented by the rate of the averaged concentration of the local domain to that of exhausted air from the room. From the age theory of air, it is well known that the averaged concentration in a room corresponds to the mean staying time of contaminant. Evaluating the domain-averaged concentration (Cdomain) means evaluating the average staying time of the contaminant in the domain. It can be only one part of the whole room and can be considered as an occupied zone. Visitation frequency (VF) and the average staying time of the contaminant for one visitation in the local domain (Tp) are introduced to analyze the average staying time of the contaminant in the local domain. The value of VF is strongly affected by the position of the local domain in the room; that is, the position of the local domain in the whole flow field of the room. Tp represents the property of the flow pattern in the local domain. As the indication of VF and Tp represent the mechanism for forming the domain-averaged concentration, they are deeply related to local purging flow rate, which represents the airflow rate for defining the domain-averaged concentration. As VF and Tp are related to the contaminant transportation property, it is effective to analyze them by particle tracking method. A CFD method of large eddy simulation (LES) was thereby carried out in this study. The prediction result by LES is also validated by a precise model experiment. In this paper, the detailed analysis of VF and Tp is carried out on the basis of the particle tracking method utilizing the LES result in order to clarify the mechanism of the domain-averaged concentration. The analyzed room has one supply inlet and one exhaust outlet. A clear re-circulating flow, generated by the forced ventilation, is observed in the room. The value of VF is examined with three types of local domains in the room model. In the room model, VF shows a value of 5.70 when the local domain occupies half of the room. It becomes smaller when the size of the local domain is reduced.

Air Movements↗
PubMed2003

Glucocorticoid suppression of nuclear factor-kappa B: a role for histone modifications.

Corticosteroids are by far the most effective treatment for chronic inflammatory diseases such as asthma. Inflammation in asthma is characterized by the increased expression of multiple inflammatory genes, including those that encode cytokines, chemokines, adhesion molecules, and inflammatory enzymes and receptors. Increased expression of inflammatory genes is regulated by pro-inflammatory transcription factors, such as nuclear factor kappa B (NF-kappa B). These bind to, and activate, co-activator molecules that then acetylate core histones resulting in elevated gene transcription. Corticosteroids reverse histone acetylation at the site of inflammatory gene transcription, either by direct binding of the activated glucocorticoid receptor to NF-kappa B-associated co-activators or by recruitment of histone deacetylases to the activated transcription complex. Understanding how corticosteroids work in asthma may help in designing novel corticosteroids with fewer systemic effects, as well as novel anti-inflammatory approaches.

Acetylation↗
PubMed2003

Significance of extensive Mongolian spots in Hunter's syndrome.

BACKGROUND: The importance of early diagnosis in infants with a mild form of Hunter's syndrome should be emphasized. If applied sufficiently early, haematopoietic stem cell transplantation (HSCT) or recombinant enzyme therapy may improve the prognosis. At present, however, diagnosis of the mild form of Hunter's syndrome tends to be delayed, especially in infants with relatively normal intelligence. OBJECTIVES: To investigate the occurrence of Mongolian spots in infants with Hunter's syndrome, and to clarify the relationship between the Mongolian spots and Hunter's syndrome clinically and histopathologically. METHODS: Seven Japanese boys with Hunter's syndrome who had received HSCT at ages 4-11 years were observed. The cutaneous manifestations of Mongolian spots before HSCT were evaluated, and compared with those after HSCT. In two patients, the hyperpigmentation from the Mongolian spots was examined by light and electron microscopy. RESULTS: Pre-HSCT observation revealed that all the patients had an extensive Mongolian spot. These were present at birth and have shown no signs of resolution during the post-HSCT period. Electron microscopic findings showed that pigment-bearing dermal melanocytes contained many free melanosomes in stage IV. These were surrounded by extracellular sheaths and encircled by elastic fibres. CONCLUSIONS: Our results indicate a strong clinical correlation between the extensive Mongolian spots and Hunter's syndrome. Ultrastructural findings also clearly suggest that the hyperpigmentation is a long-lasting symptom. The recognition of the extensive Mongolian spots is essential as it may lead to early diagnosis in patients with a mild form of Hunter's syndrome.

Child↗
PubMed2003

Changes in the distribution pattern of gelatin-binding protein of 28 kDa (adiponectin) in myocardial remodelling after ischaemic injury.

AIMS: Gelatin-binding protein of 28 kDa (GBP28) is a collagen-like plasma protein having a binding capacity with collagens. We investigated GBP28 role on myocardial remodelling as well as the diagnostic significance of GBP28 immunostaining in myocardial infarction. METHODS AND RESULTS: Myocardial tissues obtained from 47 autopsied hearts with infarction were immunostained with antibodies against GBP28, fibronectin, type III and IV collagens, and prolyl 4-hydroxylase. GBP28 was distributed in interstitium of infarcted lesions at an early stage. GBP28 was linearly found both along the border with vital myocardium and at the periphery of surviving cardiomyocyte around the lesion at granulative stage. However, it was not observed in the scar. GBP28 distribution patterns were similar to those of fibronectin in infarcted lesions and those of type IV collagen at the periphery of cardiomyocyte. Type III collagen was not recognized in the early-stage lesion but increased along with scar maturation. Prolyl 4-hydroxylase was found in surviving cardiomyocytes around the lesion during all stages and in interstitial cells appeared in granulation tissue. CONCLUSION: GBP28 plays a role as a scaffold of newly formed collagen in myocardial remodelling after ischaemic injury, and GBP28 immunostaining may assist in a diagnosis of healing stage.

Adiponectin↗
PubMed2003

Detection of Streptococcus anginosus from saliva by real-time polymerase chain reaction.

AIMS: The purpose of the present investigation was to assess the salivary levels of Streptococcus anginosus in periodontitis patients. METHODS AND RESULTS: The salivary levels of Strep. anginosus were assessed using real-time polymerase chain reaction (PCR). Streptococcus anginosus was detected in 28 of 37 (75.6%) of periodontitis patients and in three of the 20 (15%) healthy subjects. The mean values for bleeding on probing and probing depth in positive patients were statistically higher than those in negative patients. A significant decrease in Strep. anginosus levels was observed after periodontal treatment. CONCLUSIONS: Although the levels of Strep. anginosus are extremely low, they may reflect the status of periodontal health. SIGNIFICANCE AND IMPACT OF THE STUDY: Real-time PCR is a useful method for obtaining the relative quantities of Strep. anginosus from saliva samples and for monitoring the effect of therapy.

Adult↗
PubMed2003

A comparison of the end-tidal CO2 measured by portable capnometer and the arterial PCO2 in spontaneously breathing patients.

An end-tidal CO2 (ETCO2) monitor (capnometer) is used most often as a noninvasive substitute for PaCO2 in anesthesia, anesthetic recovery and intensive care. However, the utility and accuracy of the portable capnometer in spontaneously breathing patients with or without chronic pulmonary diseases has received little recognition. To determine the utility of the portable capnometer in general wards and in in-home care, we examined the correlation between ETCO2 measured by a portable capnometer and simultaneous PaCO2 measured in 41 spontaneously breathing patients. TV-ETCO2 (ETCO2 measured by tidal volume maneuver) was lower than PaCO2 by an average of 9.0 mmHg and VC-ETCO2 (ETCO2 measured by vital capacity maneuver) was lower than PaCO2 by an average of 0.5 mmHg. The mean difference between PaCO2 and VC-ETCO2 was not statistically significant. Regression analysis showed a close correlation between VC-ETCO2 and PaCO2 (r = 0.91, P < 0.0001). Thus,VC-ETCO2 was highly correlated with PaCO2. Furthermore, a close correlation between VC-ETCO2 and PaCO2 was also observed in patients with compromised pulmonary function (r = 0.88, P < 0.0001 in patients with below 70% of FEV(1.0)%; r = 0.89, P < 0.0001 in patients with below 80% of %VC). Our studies show that VC-ETCO2 measured by the portable capnometer gives a reliable pointestimate of PaCO2, and can be useful to evaluate the respiratory condition of spontaneously breathing patients in general wards and in in-home care.

Aged↗
PubMed2003

Ferguson Smith type multiple keratoacanthomas and a keratoacanthoma centrifugum marginatum in a woman from Japan.

We report a case of multiple keratoacanthomas on the sun-exposed skin of a 37-year-old woman from Japan. She had experienced 4 similar episodes of evolution and involution of multiple keratoacanthomas during a period of 10 years since she was 27 years old. She was given the diagnosis of Ferguson Smith type keratoacanthoma. This is the seventh Japanese case of Ferguson Smith type keratoacanthoma described in detail in the literature. In addition, the patient was found to have an annular, coral reef-like eruption on the front of her neck, which was diagnosed as a keratoacanthoma centrifugum marginatum. A combination of different variants of keratoacanthoma in 1 patient is uncommon, and only 2 patients with the same combination of lesions, as that seen in our patient, have been reported. Our patient was treated by a relatively low dose (0.5 mg/kg body weight) of etretinate. Both variants of keratoacanthoma showed good response to the treatment. Effectiveness of etretinate for treating keratoacanthoma centrifugum marginatum has only been reported in a few cases. Our patient had no relapse during a period of 15 months after cessation of etretinate treatment.

Adult↗
PubMed2003

Morphologic and histopathologic changes in the bowel after super-selective transcatheter embolization for focal lower gastrointestinal hemorrhage.

PURPOSE: To evaluate the safety of superselective arterial embolization therapy in the lower gastrointestinal tract. The sequelae on normal enteric tissue in lower gastrointestinal arterial embolization were retrospectively reviewed. MATERIAL AND METHODS: To control hemorrhage and tumor blood supply, 14 patients were treated by superselective transcatheter embolization at different levels of the colonic and small intestine vessels via the superior and inferior mesenteric arteries using microcoils and/or gelatin sponge. Normal enteric tissues in the embolized areas were analyzed for the occurrence of ischemic changes by clinical follow-up, colonoscopy, and surgery. RESULTS: Normal bowel function was preserved in 13 patients. In 1 patient treated with numerous gelatin sponge particles delivered from the proximal arcade of the superior mesenteric artery, significant muscular fibrosis occurred. CONCLUSION: Superselective arterial embolization for lower gastrointestinal hemorrhage can be safely performed by minimizing the amount of embolic materials and delivering them as distally as possible.

Colon↗
PubMed2003

Combined study with FDG PET and Tl SPECT in patients with idiopathic dilated cardiomyopathy.

This study aimed to determine whether combined examinations of myocardial 2-[18F]fluoro-2-deoxy-D-glucose positron emission tomography (FDG PET) and stress-redistribution 201Tl single-photon emission computed tomography (Tl SPECT) were useful in clarifying myocardial ischaemia and evaluating the prognosis in patients with idiopathic dilated cardiomyopathy (IDCM). Twenty-two patients with IDCM underwent echocardiography, cardiac catheterization, FDG PET, and Tl SPECT. In scintigraphic analysis, the total defect score (TDS) was semiquantitatively determined as the sum of scores of the 17 left ventricular (LV) segments with a 5-point scale (0 as normal to 4 as absent). Patients were classified according to the scintigraphic findings as follows: eight patients with small defects on Tl and FDG (TDS < or = 20) (group I), eight patients with small defects on FDG (TDS < or = 20) with FDG uptake increased relative to Tl or 'mismatch' (group II), and six patients with large defects on FDG and Tl (TDS >20) (group III). Eleven patients (50%) showed reversible defects on Tl and all showed preserved FDG uptake. The patients in group III had significantly lower LV ejection fraction (LVEF) (P<0.05, respectively) and a poorer prognosis as shown by the Kaplan-Meier event-free curve compared with those in groups I and II (P<0.01, respectively). Although patients in group II had significantly greater TDS on Tl compared with those in group I (P<0.01), no significant differences in LVEF and prognosis were found between patients in groups I and II. In multivariate analysis, a TDS on FDG revealed an independent predictor of subsequent cardiac events. In conclusion, such mismatched areas can be assumed to consist of impaired but viable myocardium, and may be associated with ischaemia of the microvasculature. Impaired myocardial glucose metabolism is a more powerful predictor of future cardiac events than perfusion abnormality in patients with IDCM.

Age Factors↗