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Biomedical subjects

T Kawakami

Publications and source records attributed to T Kawakami.

At least 109 records · Page 6Linked to original sources
PubMed2000

Effect of food size on the movement of the mandibular first molars and condyles during deliberate unilateral mastication in humans.

To date, the effect of food size on the movement of the mandibular first molars and condyles during chewing has not been fully examined due to methodological problems. The purpose of the present study was to examine the previously unknown effect of food size on masticatory jaw movement. Using a face bow, light-emitting diodes, and optical cameras, we recorded, in 16 young adults with good occlusion, mandibular movement for the first 10 strokes during the unilateral chewing of similarly shaped hard gummy jellies weighing 5 g and 10 g, respectively. The chewing cycle time for the 10-g jelly was significantly longer than that for the 5-g jelly. The jaw-closing and -opening maximum velocities, gapes at the maximum velocities, and maximum gape were significantly faster and larger when 10-g gummy jellies were chewed, compared with results with 5-g jellies, at the mandibular first molar on the chewing side and the condyle on the non-chewing side. With the exception of the velocity, similar tendencies were observed at the molar on the non-chewing side. However, such significant differences were not detected at the condyle on the chewing side. The mandibular first molar on the chewing side was that most affected by food size, and the mean value of the maximum gape coincided approximately with the height of each jelly. These results suggest that humans chew hard coherent food such that the mandibular teeth that come into contact with the food open to a height equivalent to that of the food bolus, and that the changes in movement of the other parts of the mandible are minimized, ensuring efficient mastication.

Adult↗
PubMed2000

Clinicopathological analysis of premature infants treated with artificial surfactant.

OBJECTIVE: Our aim was to obtain new information about the relationship between infant responses to surfactant replacement therapy and histopathological changes in vital organs. STUDY DESIGN: To accomplish this, the autopsy findings and clinical backgrounds of 41 very low birth weight infants (gestational week 25.6 +/- 2.3; birth weight 806.4 +/- 251.6g) who had died after receiving surfactant replacement therapy were reviewed, and those who responded to therapy were compared with those who did not. Responders were infants in whom the required FiO(2) declined by > 20% or mean airway pressure declined by > 20% within six hours of instilling surfactant (n=18); non-responders were infants who did not meet those criteria (n=23). RESULT: Gestational age, birth weight and time at treatment were similar in responders and non-responders, but survival was significantly longer in responders. The incidences of hyaline membrane disease, pulmonary interstitial emphysema, hemorrhagic necrosis and parenchymal degeneration of the liver and kidney were all higher in non-responders, whereas the incidences of bronchopulmonary dysplasia and pneumonia were higher in responders. Prior to treatment, acidosis and hypothermia were significantly more severe in non-responders, and perinatal complications, such as fetal distress and intrauterine infection, were observed more often in non-responders. Substantial degradation of vital organs had already occurred during the early post-natal or intrauterine life of the non-responders, which would be expected to interfere with the clinical response to instilled surfactant. CONCLUSION: It is anticipated that in the future improved monitoring of immature fetuses will be indispensable to improve intrauterine fetal management and to achieve better control over the timing and mode of delivery.

Gestational Age↗
PubMed2000

Calbindin D-28k immunoreactive nerve fibers in the carotid body of normoxic and chronically hypoxic rats.

The distribution and ultrastructural characteristics of calbindin D-28k immunoreactive nerve fibers were examined in the carotid body of the normoxic control rats by light and electron microscopy, and the abundance of calbindin D-28k fibers in the carotid body was compared in normoxic and chronically hypoxic rats (10% O2 and 3.0-4.0% CO2 for 3 months). Calbindin D-28k immunoreactivity was recognized in nerve fibers within the carotid body. Calbindin D-28k immunoreactive nerve fibers appeared as thin processes with many varicosities. They were distributed around clusters of glomus cells, and around blood vessels. Immunoelectron microscopy revealed that the calbindin D-28k immunoreactive nerve terminals are in close apposition with the glomus cells, and membrane specialization is visible in some terminals. Some dense-cored vesicles in the glomus cells were aggregated in this contact region. The chronically hypoxic carotid bodies were found to be enlarged several fold, and a relative abundance of calbindin D-28k fibers was lesser than in the normoxic carotid bodies. When expressed by the density of varicosities per unit area of the parenchyma, the density of calbindin D-28k fibers associated with the glomus cells in chronically hypoxic carotid bodies was decreased by 70%. These immunohistochemical findings indicate a morphological basis for involvement of calcium binding protein in the neural pathway that modulates carotid body chemoreception.

Animals↗
PubMed2000

Changes in the immunoreactivity of substance P and calcitonin gene-related peptide in the laryngeal taste buds of chronically hypoxic rats.

The distribution of substance P (SP)- and calcitonin gene-related peptide (CGRP)-immunoreactive nerve fibers in the taste buds of the epiglottis and aryepiglottic folds was compared between normoxic control and chronically isocapnic hypoxic rats (10% O2 and 3-4% CO2 for 3 months). In the normoxic laryngeal taste buds, SP- and CGRP-immunoreactive fibers were detected within the taste buds, where they appeared as thin processes with many varicosities. Most CGRP fibers showed coexistence with SP, but a few fibers showed the immunoreactivity of CGRP only. The density of intra- and subgemmal SP and CGRP fibers penetrating into the laryngeal taste buds was significantly higher in chronically hypoxic rats than in normoxic control rats. Water intake in the hypoxic rats was significantly lower than in the normoxic rats. These results indicate that the increased density of SP- and CGRP-containing nerve fibers within the laryngeal taste buds is a predominant feature of hypoxic adaptation. The altered peptidergic innervation and reduced water intake support the hypothesis that the laryngeal taste buds are involved in water reception, and that the water reception may be under the control of peptidergic innervation.

Animals↗
PubMed2000

Anti-malarial activity of leaf-extract of hydrangea macrophylla, a common Japanese plant.

To find a new anti-malarial medicine derived from natural resources, we examined the leaves of 13 common Japanese plants in vitro. Among them, a leaf-extract of Hydrangea macrophylla, a common Japanese flower, inhibited the parasitic growth of Plasmodium falciparum. The IC50 of Hydrangea macrophylla leaf extract to Plasmodium falciparum was 0.18 microg/ml. The IC50 to NIH 3T3-3 cells, from a normal mouse cell line, was 7.2 microg/ml. Thus, selective toxicity was 40. For the in vivo test, we inoculated Plasmodium berghei, a rodent malaria parasite, to ddY mice and administered the leaf-extract of Hydrangea macrophylla (3.6 mg/0.2 ml) orally 3 times a day for 3 days. Malaria parasites did not appear in the blood of in the treated mice, but they did appear in the control group on day 3 or 4 after inoculation with the parasites. When leaf extract was administered to 5 mice 2 times a day for 3 days, malaria parasites did not appear in 4 of the mice but did appear in 1 mouse. In addition, the leaf-extract was administered orally 3 times a day for 3 days to Plasmodium berghei infected mice with a parasitemia of 2.7%. In the latter group, malaria parasites disappeared on day 3 after initiating the treatment, but they appeared again after day 5 or 6. Although we could not cure the mice entirely, we confirmed that the Hydrangea macrophylla leaf extract did contain an anti-malarial substance that can be administered orally.

Animals↗
PubMed2000

[Significance of exercise-induced ST segment depression in patients with myocardial infarction involving the left circumflex artery: evaluation by exercise thallium-201 myocardial single photon emission computed tomography].

The significance of exercise-induced ST segment depression in patients with left circumflex artery involvement was investigated by comparing exercise electrocardiography with exercise thallium-201 single photon emission computed tomography(Tl-SPECT) and the wall motion estimated by left ventriculography. Tl-SPECT and exercise electrocardiography were simultaneously performed in 51 patients with left circumflex artery involvement(angina pectoris 30, myocardial infarction 21). In patients with myocardial infarction, exercise-induced ST depression was frequently found in the V2, V3 and V4 leads. In patients with angina pectoris, ST depression was frequently found in the II, III, aVF, V5 and V6 leads. There was no obvious difference in the leads of ST depression in patients with myocardial infarction with ischemia and without ischemia on Tl-SPECT images. In patients with myocardial infarction, the lateral wall motion of the infarcted area evaluated by left ventriculography was more significantly impaired in the patients with ST depression than without ST depression(p < 0.01). Exercise-induced ST depression in the precordial leads possibly reflects wall motion abnormality rather than ischemia in the lateral infarcted myocardium.

Aged↗
PubMed2000

[Acute myocardial infarction in elderly patients: medical and social problems].

The number of elderly patients with acute myocardial infarction has been increasing. However, the choice of treatment remains controversial. Medical records of 310 consecutive patients with acute myocardial infarction were reviewed. Two retrospective analyses were performed. 1) Patients were divided into the elderly group(70 years or more) and the younger group(under 70 years). In-hospital course and outcome were compared. 2) Pre-hospital performance status and living status were reviewed in the elderly group. Acute phase reperfusion therapy was performed in fewer patients in the elderly group(60.8% vs 71.9%, p < 0.01). The difference was most pronounced in cases of direct coronary angioplasty(28.6% vs 54.7%, p < 0.05). As a result, the rate of reperfusion success(74.8% vs 86.8%, p < 0.01) was lower in the elderly group. Moreover, the rates of in-hospital death(23.6% vs 6.8%, p < 0.005), pulmonary edema(20.3% vs 10.8%, p < 0.05), cardiogenic shock(11.9% vs 6.0%, p < 0.005), pneumonia(17.3% vs 3.0%, p < 0.005), and delirium(29.4% vs 12.0%, p < 0.001) were higher in the elderly group. Five patients in the elderly group and 3 patients in the younger group required rehabilitation because of worsened performance status. Six of them were non-reperfused patients. Elderly patients considered likely to become bed-ridden because of pre-existing physical disability at admission accounted for 28.9% of the total. Moreover, many elderly patients had poor support systems (8.4% were living alone, 21.0% were living only with their spouse or a child, 30.1% were widows or widowers). These results show that a lower acute phase reperfusion rate(especially angioplasty) resulted in a poor prognosis and worse performance status in elderly patients. Also 30% of patients were not good candidates for conventional treatment because of delirium, and that self-help in daily life is a fundamental goal for most elderly patients. Rapid and simple acute phase reperfusion, subsequent immediate mobilization, and early discharge are recommended for elderly patients with acute myocardial infarction.

Activities of Daily Living↗
PubMed2000

[An unusual case of epilepsy exhibiting gelastic seizure, simple visual hallucination, and transient swelling of the left parieto-occipital region].

We report a 74-year-old man with gelastic seizure, simple visual hallucination, and adversive seizure. The patient described his visual hallucinations as "rotating light like a firefly" and "mimicking a stream". Brain CT scan showed a transient swelling as well as low density of a left parieto-occipital region. Electroencephalographic study revealed spikes and fast waves beginning at left occipital region. Although temporal lobe and hypothalamic lesions (especially hypothalamic hamartomas) are well known as origins of gelastic seizures, we could not find any report that described a series of occurrence of gelastic seizure and simple visual hallucination. Usually, simple visual hallucination is thought to occur in occipital lesion. In our case, it is possible that gelastic seizure and simple visual hallucination are related to the epileptic discharge from occipital lesion directly or indirectly. The reversible brain swelling with low density seen in the present case might be caused by cytotoxic edema due to status epilepticus.

Aged↗
PubMed2000

An experience of a case with perforation of an aneurysm in the anterior mitral cusp developing after aortic valve replacement.

Mitral valve aneurysm is a rare disease and in Japan, cases of perforation which is considered to be mainly caused by infectious endocarditis is usually only encountered through case reports. We experienced a case who received aortic valve replacement and mitral valve annuloplasty for combined valvular heart disease of aortic insufficiency and mitral insufficiency followed by mitral valve replacement for severe mitral valve regurgitation subsequent to perforation of the anterior mitral cusp, leading to recovery.

Aneurysm, Ruptured↗
PubMed2000

[A case of psoas cold abscess in a young tuberculosis patient].

A 28-year-old man was referred to our hospital with a complaint of painful induration of right epididymis accompanied with right back pain and persistent low-grade fever. He was finally diagnosed with tuberculosis by sputum culture. Abdominal computed tomography (CT) revealed right psoas abscess and vertebral caries. He underwent a percutaneous drainage of the abscess followed by multidrug (streptomycin, pyrazinamide, refanpicin, isoniazide) combination therapy. Immediately after the drainage, symptoms began to improve with these therapies. However, four months later, abdominal CT showed a worsening of the abscess. Recently there is a stagnation in the decline of incidence of tuberculosis. It is still necessary to examine young people carefully bearing urogenital tuberculosis in mind. The pathogenesis and management of this rare condition are discussed.

Adult↗
PubMed2000

[A case report of chronic myelocytic leukemia with multiple brain metastases, which responded to the gamma-knife therapy].

We report a 78-year-old woman who had multiple leukemic cell tumors in the brain in the course of chronic myelocytic leukemia (CML). As far as we could survey, such brain tumors were extremely rare. She had been followed because of chronic phase of CML until October, 1998, when she noticed muscle weakness in her left upper and lower extremity. A head MRI revealed multiple masses in the brain, a biopsy of which revealed a tumor of CML cells. Although 40 Gy gamma-knife therapy had reduced the size and numbers of brain tumors, we found recurrence of left hemiparesis and tumors three months after the gamma-knife therapy. Whole brain irradiation therapy (total 30 Gy) was somewhat effective to the tumor and hemiparesis transiently subsided. Thereafter her general condition worsened again, and she died in June, 1999, eight months after the diagnosis of the brain tumors of leukemic cells. We had not seen any other clinical evidence of generalized blastic crisis in this patient. In our case, MRI of the brain showed two patterns of metastases, tumor forming and cortical invasive type. We thought that these two patterns of brain involvement might show different responses to the radiation therapy, and it was characteristic in this patient.

Aged↗
PubMed1999

Emt/Itk associates with activated TCR complexes: role of the pleckstrin homology domain.

Expressed in mast and T-cells/inducible T cell tyrosine kinase (Emt/Itk) is a protein tyrosine kinase required for T cell Ag receptor (TCR)-induced activation and development. A physical interaction between Emt/Itk and TCR has not been described previously. Here, we have utilized laser scanning confocal microscopy to demonstrate that Ab-mediated engagement of the CD3epsilon chain induces the membrane colocalization of Emt/Itk with TCR/CD3. Removal of the Emt/Itk pleckstrin homology domain (DeltaPH-Emt/Itk) abrogates the association of the kinase with the cell membrane, as well as its activation-induced colocalization with the TCR complex and subsequent tyrosine phosphorylation. The addition of a membrane localization sequence to DeltaPH-Emt/Itk from Lck restores all of these deficiencies except the activation-induced tyrosine phosphorylation. Our data suggest that the PH domain of Emt/Itk can be replaced with another membrane localization signal without affecting the membrane targeting and activation-induced colocalization of the kinase with the TCR. However, the PH domain is indispensable for the activation-induced tyrosine phosphorylation of the kinase.

Amino Acid Sequence↗
PubMed1999

Bruton's tyrosine kinase (Btk) associates with protein kinase C mu.

Bruton's tyrosine kinase (Btk) is considered an essential signal transducer in B-cells. Mutational defects are associated with a severe immunodeficiency syndrome, X-chromosome linked agammaglobulinemia (XLA). Here we show by coimmunoprecipitation that a member of the protein kinase C (PKC) family, PKCmu, is constitutively associated with Btk. Neither antigen receptor (Ig) crosslinking nor stimulation of B-cells with phorbol ester or H(2)O(2) affected Btk/PKCmu interaction. GST precipitation analysis revealed association of the Btk pleckstrin/Tec homology domain with PKCmu. Transient overexpression of PKCmu deletion mutants as well as expression of selected PKCmu domains in 293T cells revealed that both the kinase domain and the regulatory C1 region are independently capable of binding to the Btk PH-TH domain. These data show the existence of a PKCmu/Btk complex in vivo and identify two PKCmu domains that participate in Btk interaction.

Agammaglobulinaemia Tyrosine Kinase↗
PubMed1999

A new 30-kDa ubiquitin-related SUMO-1 hydrolase from bovine brain.

SUMO-1 is a ubiquitin-like protein functioning as an important reversible protein modifier. To date there is no report on a SUMO-1 hydrolase/isopeptidase catalyzing the release of SUMO-1 from its precursor or SUMO-1-ligated proteins in mammalian tissues. Here we found multiple activities that cleave the SUMO-1 moiety from two model substrates, (125)I-SUMO-1-alphaNH-HSTVGSMHISPPEPESEEEEEHYC and/or GST-SUMO-1-(35)S-RanGAP1 conjugate, in bovine brain extracts. Of them, a major SUMO-1 C-terminal hydrolase had been partially purified by successive chromatographic operations. The enzyme had the ability to cleave SUMO-1 not only from its precursor but also from a SUMO-1-ligated RanGAP1 but did not exhibit any significant cleavage of the ubiquitin- and NEDD8-precursor. The activity of SUMO-1 hydrolase was almost completely inhibited by N-ethylmaleimide, but not by phenylmethanesulfonyl fluoride, EDTA, and ubiquitin-aldehyde known as a potent inhibitor of deubiquitinylating enzymes. Intriguingly, the apparent molecular mass of the isolated SUMO-1 hydrolase was approximately 30 kDa, which is significantly smaller than the recently identified yeast Smt3/SUMO-1 specific protease Ulp1. These results indicate that there are multiple SUMO-1 hydrolase/isopeptidases in mammalian cells and that the 30-kDa small SUMO-1 hydrolase plays a central role in processing of the SUMO-1-precursor.

Amino Acid Sequence↗
PubMed1999

Effects of glucagon on axoplasmic transport in mouse superior cervical ganglion cells.

The effects of glucagon on the axoplasmic transport of cultured mouse superior cervical ganglion cells were analyzed with the video-enhanced DIC microscope system. Glucagon increased the rate of fast axoplasmic transport by 30% in both anterograde and retrograde directions. The average velocity was increased from 1.36 +/- 0.48 microns/s to 1.74 +/- 0.43 microns/s (anterograde, n = 60) and from 1.37 +/- 0.48 microns/s to 1.62 +/- 0.39 microns/s (retrograde, n = 60). The stimulatory effect of glucagon on the axoplasmic transport was reversed in a glucose-free medium, whereas blocking the citrate cycle by pretreating neuronal cells with malonate did not alter the effect of glucagon. Together with our previous findings, our data suggest that neurotransmitters and hormones play a major role in the regulation of fast axoplasmic transport.

Animals↗