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Biomedical subjects

K Murata

Publications and source records attributed to K Murata.

At least 199 records · Page 11Linked to original sources
PubMed1999

[Computerized analysis of normal associated movements of facial mimic muscles].

There have been many reports on the synkinesis of mimic muscles following facial palsy, and many efforts have been made to evaluate the degree of synkinesis. Even in normal cases, associated movements of facial muscles can been seen. Empirically, mimic muscles move in association, e.g., when the lips are opened to grin, the lateral portion of the eyebrow moves, or when the mouth is moved as in whistling, tension around the root of the nose subconsciously builds up. Our purpose was to evaluate the movements of facial mimic muscles quantitatively, to analyze them in various facial expressions, and to obtain basic data to the objective evaluation of associated movement in normal subjects. Thirty-seven normal subjects (18 males and 19 females, aged 20 to 40 years) were included in the study. A total of 24 markers were stuck to each subject's face. The threshold image process which revealed only the markers, made it possible to trace and measure the markers on the face. The shifting positions of the markers showed that they moved in accordance with the facial movement from the stationary phase to the maximum stage of movement. These positions were measured and the traces plotted on the coordinate axis. The shifting of the markers were then numerically expressed as trajectory investigation. The facial movements examined in this study consisted of eye closing, forehead wrinkling, whistling, and grinning. We found that, quantitatively, certain groups of mimic muscles might work together to make one facial expression in all the above mentioned facial movements. In normal individuals, at least 15-20% of other mimic muscle collaboration is needed in addition to main muscles to create a facial expression. This result can serve as a reference for the evaluation of abnormal associated facial movement.

Adult↗
PubMed1999

Impact of shift work on cardiovascular functions in a 10-year follow-up study.

OBJECTIVES: The purpose of this study was to determine whether shift work affects the heart-rate-adjusted QT interval (QTc) in electorcardiography (ECG) and the blood pressure of workers without overt cardiovascular dysfunction. METHODS: At a copper smelter, 158 shift workers and 75 day workers who underwent an ECG examination and blood pressure measurements in 1986 were followed for 10 years. In 1996, biochemical indicators such as high-density lipoprotein cholesterol and triglycerides were measured, together with the QTc. RESULTS: In 1986 and 1996, the QTc was significantly longer in the shift workers than in the day workers. Of 180 workers with a normal QTc (<420 ms(1/2) in 1986, 15% had developed a prolonged QTc (420 ms(1/2) in 1996 (18% of the 117 shift workers and 11% of the 63 day workers). Among the workers with a normal QTc in 1986, the shift workers had a significantly longer QTc than the day workers when the QTc was examined in 1996. In addition, shift-day work in the group with a normal QTc was significantly related to the QTc in 1996 after control for age, work duration, biochemical indicators, smoking, and drinking habits. However, the blood pressures of the shift and day workers did not differ significantly, and in 1996 the values of both groups were significantly elevated. CONCLUSIONS: These data suggest that shift work is associated with QTc prolongation. This evidence may explain the increased risk for cardiovascular diseases due to shift work.

Adult↗
PubMed1999

[A case of hepatocellular carcinoma with tumor thrombus in the right atrium successfully treated by arterial administration of lipiodol-SMANCS].

In February, 1996, a 73-year-old male with liver dysfunction was admitted to our hospital for further examination and treatment of liver tumor. The liver tumor was revealed by imaging examination, which was mainly in the S4-S8 of liver with a thrombus growing from the right anterior branch to the right branch of the portal vein, and from the right hepatic vein to the inferior vena cava and right atrium. The serum AFP and PIVKA-II levels were elevated to 3.610 ng/ml and 54 AU/ml, respectively. The patient was diagnosed as having hepatocellular carcinoma, and was treated by arterial administration of anticancer drugs (epirubicin hydrochloride, mitomycin C and carboplatin) and TAE. Though the main tumor (S4-S8 of liver) was reduced by TAE, the portal and atrial tumor thrombus did not respond. One month after TAE (20 May, 1996), the first arterial administration of Lipiodol-SMANCS was given, followed by 4 successive procedures with an interval of about 1.5 months (total dose 15 mg), resulting in remarkable tumor thrombus shrinkage and reduction of AFP levels to 80 ng/ml. This case shows that arterial administration of SMANCS may be one of the effective treatments for hepatocellular carcinoma, even with tumor thrombus of hepatic vein, IVC and right atrium.

Aged↗
PubMed1999

Prenatal methylmercury exposure as a cardiovascular risk factor at seven years of age.

Blood pressure in childhood is an important determinant of hypertension risk later in life, and methylmercury exposure is a potential environmental risk factor. A birth cohort of 1,000 children from the Faroe Islands was examined for prenatal exposure to methylmercury, and at age 7 years, blood pressure, heart rate, and heart rate variability were determined. After adjustment for body weight, diastolic and systolic blood pressure increased by 13.9 mmHg [95% confidence limits (CL) = 7.4, 20.4] and 14.6 mmHg (95% CL = 8.3, 20.8), respectively, when cord blood mercury concentrations increased from 1 to 10 microg/liter cord blood. Above this level, which corresponds to a current exposure limit, no further increase was seen. Birth weight acted as a modifier, with the mercury effect being stronger in children with lower birth weights. In boys, heart rate variability decreased with increasing mercury exposures, particularly from 1 to 10 microg/liter cord blood, at which the variability was reduced by 47% (95% CL = 14%, 68%). These findings suggest that prenatal exposure to methylmercury may affect the development of cardiovascular homeostasis.

Blood Pressure↗
PubMed1999

[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↗
PubMed1999

[Teaching hygiene and public health with student facilitators an attempt to enhance student participation].

In order to enhance student participation in lectures of hygiene and public health, we introduced a student facilitator (SF) system into the lectures of the fourth grade medical students. All students were assigned to one of the 28 classes as SF, thus each class had 4 to 5 SFs. A few weeks before the lecture, each teacher gave SFs various instructions to prepare for the class depending on the theme and teaching strategies. Some classes consisted of dialogues between the teacher and SFs in other classes gave presentations related to the theme of the lecture. For example, SFs in a class of epidemiology performed a small epidemiological survey using their fellow students as study subjects, thus allowing students to learn epidemiological design and calculation of odds ratios. In a class of care management, SFs played roles of caregiver, family member, social worker, physician, etc., showing how actual care management is conducted. The evaluation survey for the SF system showed that in general, students rated the SF system positively, especially at the time they served as SFs. Most of the students showed more interest in the subjects and felt more confident about what they learned as compared to ordinary classes. This finding is important because, previously, the largest problem with the lectures of hygiene and public health used to be the poor interest of students in the subject itself. On the other hand, students sometimes complained about the poor quality of the presentation by SFs. Also, a few students sometimes felt that for obtaining the large volume of knowledge required by the national board examination for medical practice, the SF system was inefficient. In summary, the SF system has some advantage in evoking interests in learning hygiene and public health with sufficient systematic preparation. However, it may not be an efficient way to simply obtain large amounts of knowledge. To improve the SF system, well designed teaching strategies in addition to a carefully prepared textbook are essential.

Education, Medical, Undergraduate↗
PubMed1999

[Recent advances in CT diagnosis of chronic obstructive pulmonary diseases].

With high-resolution CT (HRCT), morphological changes of the lung caused by chronic obstructive pulmonary disease can be evaluated in detail at the level of secondary pulmonary lobule. The location of emphysematous lesions within the lobule can be judged on HRCT images and bronchiolar abnormalities are also demonstrated as thickening of peripheral bronchovascular bundles. In addition to early detection of morphological changes, quantitative evaluation of the severity of the disease is also important. For this purpose, visual assessment with CT scores, quantitative evaluation using "density mask" technique, or histogram analysis are employed. Quantitative parameters provided by these methods correlate well with pathological scores and results of pulmonary function tests. Furthermore, respiratory dynamic CT or paired inspiratory and expiratory CT is also useful to detect air trapping caused by bronchiolar stenosis.

Humans↗
PubMed1998

A structural feature in the central channel of the bacterial flagellar FliF ring complex is implicated in type III protein export.

The FliF ring complex, which consists of the M-S ring and a proximal portion of the rod of the flagellar basal body, is the base structure for the bacterial flagellar assembly. The FliF ring is also thought to be part of the export apparatus for flagellar proteins from its amino acid sequence homology to proteins involved in type III protein export systems. We established a new purification procedure for the FliF ring particles and carried out electron microscopic image analyses in their two distinct forms: well-dispersed single particles in the presence of salt and ordered monolayer arrays of hexagonal packing formed in the absence of salt. In both cases, the axial projection maps showed a common feature, a pair of concentric rings: the inner ring corresponds to the proximal rod; the outer ring represents the thick, edge portion of the M-S ring. However, the central channel of the FliF ring, the putative pathway for the flagellar protein export, appeared to show distinct structural features in the two forms. This suggests that a domain of FliF partially occupies the central channel to be involved in the export and gate mechanism, and the domain changes its conformation depending on the ionic strength.

Amino Acid Sequence↗
PubMed1998

IKP104-induced decay of tubulin: role of the A-ring binding site of colchicine.

Tubulin, the major subunit protein of microtubules, has a tendency to lose its ability to assemble or to interact with ligands in a time-dependent process known as decay. Decay involves the increase in exposure of sulfhydryl groups and hydrophobic areas. The antimitotic drug IKP104 [2-(4-fluorophenyl)-1-(2-chloro-3, 5-dimethoxyphenyl)-3-methyl-6-phenyl-4(1H)-pyridinone] accelerates the decay of tubulin [Ludueña et al. (1995) Biochemistry 34, 15751-15759]. In the presence of colchicine, however, IKP104 stabilizes tubulin against decay. We have shown that the stability and the acceleration of the decay of tubulin are mediated respectively by the high- and low-affinity binding site(s) of IKP104 [Chaudhuri et al. (1998) J. Protein Chem. 17, 303-309]. To better understand the mechanism by which colchicine protects tubulin from IKP104-induced decay, we examined the effect of colchicine and its analogues on this process. We found that IKP104 unfolds tubulin in a process involving a specific domain where colchicine interacts, although the binding sites of these two drugs are distinctly different. 2-Methoxy-5-(2',3',4'-trimethoxyphenyl) tropolone (MTPT), the bicyclic analogue of colchicine that lacks the B-ring, can also protect tubulin from IKP104-induced decay. An A-ring analogue of colchicine, 3,4,5-trimethoxybenzaldehyde (TMB), can also stop IKP104-induced unfolding of tubulin significantly. Interestingly, the C-ring analogue of colchicine, tropolone methyl ether (TME), does not prevent this process. Our results thus suggest that neither the B-ring nor the C-ring binding regions of colchicine are involved in the IKP104-induced decay and that the A-ring binding site of colchicine on tubulin plays a crucial role in IKP104-induced decay.

Alkylation↗
PubMed1998

Molecular cloning of two genes for beta-D-glucosidase in Bacillus sp. GL1 and identification of one as a gellan-degrading enzyme.

In the bacterium Bacillus sp. GL1, gellan is depolymerized to give a tetrasaccharide by extracellular gellan lyase and then the tetrasaccharide is converted to constituent monosaccharides by intracellular glycosidases. Two genes encoding one of the glycosidases, beta-D-glucosidase (Bgl), were cloned in a genomic DNA library of the bacterium constructed in Escherichia coli and nucleotide sequences of the genes were determined. One of the genes, termed bglA, contained an open reading frame (ORF) consisting of 1344 base pairs coding a polypeptide (BglA) with a molecular mass of 51 kDa and the other, termed bglB, 2268 base pairs coding a protein (BglB) with a molecular mass of 82 kDa. By homology analyses of the ORFs against protein sequence databases, beta-D-glucosidase A (BglA) and beta-D-glucosidase B (BglB) were found to be classified into subfamilies BGA and BGB of cellulase family BG, respectively. BglA and BglB purified from E. coli were monomeric enzymes with molecular masses of 50 and 82 kDa and most active at pH 6.0 and 8.0, respectively. BglA showed broader substrate specificity than BglB. Only BglA acted on the tetrasaccharide produced from gellan by gellan lyase and released glucose from the molecule.

Amino Acid Sequence↗
PubMed1998

Enhancement of NO production in activated macrophages in vivo by an antimalarial crude drug, Dichroa febrifuga.

The effect of an antimalarial crude drug, Dichroafebrifuga Lour. on nitric oxide (NO) production in bacillus Calmette Guérin-induced mouse peritoneal macrophages activated by lipopolysaccharide was investigated. The NO production was significantly enhanced by an oral administration of a MeOH extract of D. febrifuga. Febrifugine (1) was isolated as the main active compound, and the activation was dose-dependent in the dosage range of 0.1-1 mg/kg/day.

Animals↗
PubMed1998

Behavior of heavy metals in human urine and blood following calcium disodium ethylenediamine tetraacetate injection: observations in metal workers.

To evaluate the effects of calcium disodium ethylenediamine tetraacetate (CaEDTA) on the behavior of 8 heavy metals in human urine and blood, CaEDTA was administered for 1 h by intravenous injection to 18 male metal foundry workers, whose blood lead concentrations (PbB) were between 16 and 59 (mean 34) microg/dl. Significant increases were found in urinary excretion of manganese, chromium, lead, zinc, and copper after the start of CaEDTA injection. Urinary chromium excretion reached a maximal level within 1 h after the start of injection, while urinary manganese, lead, and zinc excretion reached their highest concentrations between 1 and 2 h. Urinary copper excretion reached the highest level between 2 and 4 h. The rapid increases in urinary excretion of five metals were different from the "circadian rhythms," which are the normal, daily variations in renal glomerular filtration, reabsorption, and excretory mechanisms. Plasma lead concentrations were highest 1.5 h after the start of the 1-h injection, while plasma zinc concentration became lowest 5 h after the start of CaEDTA injection. Data suggest that manganese and chromium absorbed in human tissues might be mobilized by CaEDTA.

Adult↗
PubMed1998

Polysaccharide lyase: molecular cloning of gellan lyase gene and formation of the lyase from a huge precursor protein in Bacillus sp. GL1.

A bacterium, Bacillus sp. GL1, produced constitutively the extracellular polysaccharide-degrading enzyme (gellan lyase) with a molecular mass of 140 kDa. A genomic DNA library of the bacterium was constructed in Escherichia coli using the cosmid vector, Charomid 9-36. The gene encoding the lyase was cloned by screening for a gellan-degrading phenotype in E. coli cells and the nucleotide sequence of the gene was determined. The gene contained an open reading frame consisting of 7425 base pairs coding a polypeptide with a molecular mass of 263 kDa. The polypeptide contained the same amino acid sequence as N-terminal amino acid sequence of the enzyme and exhibited no homology with any previously published protein sequences. E. coli cells transformed with the gene exhibited gellan lyase activity and produced a protein with a molecular mass of about 260 kDa intracellularly. The protein was purified and shown to have the closely similar enzymatic properties to those of the native enzyme from Bacillus sp. GL1 with respect to optimal pH and temperature for activity, substrate specificity, and the mode of enzyme action. These results suggest that, in Bacillus sp. GL1, gellan lyase is first produced as a huge precursor protein (263 kDa) and then the protein is posttranslationally processed into extracellular mature form (140 kDa) through excising C-terminal peptide of about 120 kDa.

Amino Acid Sequence↗
PubMed1998

Interleukin-15 (IL-15) can replace the IL-2 signal in IL-2-dependent adult T-cell leukemia (ATL) cell lines: expression of IL-15 receptor alpha on ATL cells.

Interleukin-15 receptor (IL-15R) and IL-2R have the same beta and gamma chains, but IL-15R has a specific alpha chain distinct from that of IL-2Ralpha, which is indispensable for the high affinity binding of IL-15. In the present study, we examined four IL-2-dependent adult T-cell leukemia (ATL) cell lines for their IL-15R expression. All cell lines bound IL-15, which was not inhibited by a 100-fold excess amount of IL-2, proliferated in response to IL-15 to the same degree as to the stimulation with IL-2, and were maintained without IL-2. The responses to 1L-15 were inhibited by the antibodies against IL-2R beta or gamma chains but was not by the IL-2R alpha chain antibody. [125I]-IL-15 exhibited a single high-affinity binding with an apparent kd of 0.17 nmol/L. Reverse transcription-coupled polymerase chain reaction (RT-PCR) showed that the cell lines had the mRNA of IL-15R alpha. The cell lines also had IL-15 mRNA. Despite the presence of IL-15 mRNA, the cell lines did not secrete IL-15, and the culture supernatants of fresh ATL cells and plasma from the patients did not contain a detectable amount of IL-15 with a few exceptional cases, although fresh ATL cells also responded to IL-15. These results suggest that ATL cells have the complete form of IL-15R and respond to IL-15. Such an IL-15-dependent cell proliferation mechanism might be used in the development of ATL and for the invasion and proliferation of ATL cells in the visceral organs.

Adult↗
PubMed1998

The location of Z- and W-linked marker genes and sequence on the homomorphic sex chromosomes of the ostrich and the emu.

Perhaps the most striking fact about early Cenozoic avian history some 70 million years ago was the rapid radiation of large, flightless, ground-living birds. It has been suggested that, for a time, there was active competition between these large terrestrial birds and the early mammals. Probably reflecting the above noted early start of Ratitae of the infraclass Eoaves, the presumptive sex chromosomes of their present day survivors, such as the emu and the ostrich, largely remained homomorphic. The signs of genetic differentiation between their still-homomorphic Z and W chromosomes were tested by using two marker genes (Z-linked ZOV3 and the gene for the iron-responsive element-binding protein) and one marker sequence of a part of a presumptive pseudogene (W-linked EE0.6 of the chicken). Their homologues, maintaining 71-92% identities to the chicken counterparts, were found in both the emu (Dromaius novaehollandiae) and the ostrich (Struthio camelus). Their locations were visualized on chromosome preparations by fluorescence in situ hybridization. In the case of the emu, these three marker sequences were localized on both members of the fifth pair of a female, thus revealing no sign yet of genetic differentiation between the Z and the W. The finding was the same with regard to both members of the fourth pair of male ostriches. In the female ostrich, however, the sequence of the gene for the iron-responsive element-binding protein was missing from one of the pairs, thus revealing the differentiation by a small deletion of the W from the Z.

Animals↗
PubMed1998

Projection map of the reaction center-light harvesting 1 complex from Rhodopseudomonas viridis at 10 A resolution.

The photosynthetic reaction center-light harvesting 1 complex from Rhodopseudomonas viridis was purified and reconstituted into two-dimensional crystals. The single-layered crystalline sheets with lattice parameters a=b=133.3 A and gamma=120 degrees were investigated by electron cryo-microscopy and the projection map at 10 A resolution was calculated. The opening diameter of the light-harvesting ring of 72 A is sufficient to allow slight movement of the reaction center within the ring. Based on characteristic features observed in the projection map, the mechanism of energy transfer from the light-harvesting 1 complex to the reaction center was discussed.

Bacterial Proteins↗