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Biomedical subjects

N Morita

Publications and source records attributed to N Morita.

At least 19 recordsLinked to original sources
PubMed2006

A metastatic haemangiopericytoma of the floor of the mouth.

A case of metastatic haemangiopericytoma in the floor of the mouth is described. Haemangiopericytoma is a relatively rare slow-growing vascular tumour with variable malignant potential. This tumour has been identified in almost every region of the body, but its occurrence in the oral cavity has been rarely reported. The rate of regional and distant metastasis of the tumour is low. This case, presented 12 years after initial surgery suggested the need for careful long-term follow-ups of patients with haemangiopericytoma.

Antigens, CD34↗
PubMed2006

Positive end-expiratory pressure ventilation increases extravascular lung water due to a decrease in lung lymph flow.

Positive end-expiratory pressure (PEEP) is used to improve gas exchange, increase functional residual capacity, recruit air spaces, and decrease pulmonary shunt in patients suffering from respiratory failure. The effect of PEEP on extravascular lung water (EVLW), however, is still not fully understood. This study was designed as a prospective laboratory experiment to evaluate the effects of PEEP on EVLW and pulmonary lymph flow (QL) under physiologic conditions. Twelve adult sheep were operatively prepared to measure haemodynamics of the systemic and pulmonary circulation, and to assess EVLW In addition, the lung lymphatic duct was cannulated and a tracheostomy performed. The animals were then mechanically ventilated in the awake-state without end-expiratory pressure (PEEP 0). After a two-hour baseline period, PEEP was increased to 10 cmH2O for the duration of two hours, and then reduced back to 0 cmH2O. Cardiopulmonary variables, QL, and arterial blood gases were recorded intermittently; EVLW was determined two hours after each change in PEEP. The increase in PEEP resulted in a decrease in QL (7 +/- 1 vs 5 +/- 1 ml/h) and an increase in EVLW (498 +/- 40 vs 630 +/- 58 ml; P<0.05 each) without affecting cardiac output. As PEEP was decreased back to baseline, QL increased significantly (5 +/- 1 vs 10 +/- 2 ml/h), whereas EVLW returned back to baseline. This study suggests that institution of PEEP produces a reversible increase in EVLW that is linked to a decrease in QL.

Animals↗
PubMed2004

Centrosome hyperamplification and chromosomal damage after exposure to radiation.

OBJECTIVE: In order to elucidate the effects of radiation on centrosome hyperamplification (CH), we examined the centrosome duplication cycle in KK47 bladder cancer cells following irradiation. METHODS: KK47 cells were irradiated with various doses of radiation and were examined for CH immunostaining for gamma-tubulin. RESULTS: Nearly all control cells contained one or two centrosomes, and mitotic cells displayed typical bipolar spindles. The centrosome replication cycle is well regulated in KK47. Twenty-four hours after 5-Gy irradiation, approximately 80% of irradiated cells were arrested in G2 phase, and at 48 h after irradiation, 56.9% of cells contained more than two centrosomes. Laser scanning cytometry performed 48 h after irradiation showed the following two pathways: (1) unequal distribution of chromosomes to daughter cells, or (2) failure to undergo cytokinesis, resulting in polyploidy. With mitotic collection, M-phase cells with CH could be divided into G1 cells with micronuclei and polyploidal cells. Fluorescence in situ hybridization analysis showed clear signs of chromosomal instability (CIN) at 48 h after irradiation. The present study had two major findings: (1) continual duplication of centrosomes occurred in the cell cycle-arrested cells upon irradiation, leading to centrosome amplification; (2) cytokinesis failure was due to aberrant mitotic spindle formation caused by the presence of amplified centrosomes. Abnormal mitosis with amplified centrosomes was detected in the accumulating G2/M population after irradiation, showing that this amplification of centrosomes was not caused by failure to undergo cytokinesis, but rather that abnormal mitosis resulting from amplification of centrosomes leads to cytokinesis block. CONCLUSION: These results suggest that CH is a critical event leading to CIN following exposure to radiation.

Blotting, Western↗
PubMed2003

Diagnosis of acute brain-stem infarcts using diffusion-weighed MRI.

There are many reports on acute cerebral infarcts diagnosed by diffusion-weighted MRI (DWI), but few describe brain-stem infarcts diagnosed by this method. Using the apparent diffusion coefficient (ADC), we studied 18 consecutive patients with brain-stem infarcts who underwent DWI during the acute phase. We calculated and compared the ADC ratio (lesion ADC/contralateral ADC) in 10 patients with brain-stem and 23 with supratentorial cortical infarcts examined within 24 h of the onset of stroke. Ischaemic brain-stem lesions were detected in all 15 patients who underwent DWI more than 3 h after the onset, but not in two who had DWI within 3 h of the onset; their ADC ratio was more than 0.95. ADC ratios in patients with brain-stem infarcts decreased as the interval between onset and DWI increased; the decrease was slower than in patients with supratentorial cortical infarcts.

Acute Disease↗
PubMed2002

A characteristic feature of acute haematomas in the brain on echo-planar diffusion-weighted imaging.

Diffusion-weighted MRI (DWI) is used in the diagnosis of acute ischaemic disease of the brain, but it is not clear whether or not it can be used to differentiate an acute haematoma from an infarct. Our purpose was to identify any characteristic feature of acute haematomas which can be recognised on DWI and to evaluate the usefulness of DWI in acute cerebral stroke. We examined nine patients with acute haemorrhage using CT and MRI including DWI. We measured the volume and apparent diffusion coefficient (ADC) of the haematomas. All showed heterogeneous signal on DWI, and the centre of the large (>20 ml) haematomas especially a mixed pattern with high and low signal. The characteristic feature of acute haematomas was a peripheral low-signal region, found in all subjects regardless of the size of the haematoma; acute infarcts did not show this. This low-signal rim on DWI may be useful for differentiating an acute haematoma from an infarct.

Adult↗
PubMed2001

Synthesis and redox behavior of azulene-substituted benzene derivatives and (eta(5)-cyclopentadienyl)[tetra- and di(6-azulenyl)cyclobutadiene]cobalt complexes.

1,2-Di(6-azulenyl)tetraphenylbenzenes and (6-azulenyl)pentaphenylbenzenes were synthesized by Diels-Alder reactions of di(6-azulenyl)acetylenes and 6-(phenylethynyl)azulenes with tetraphenylcyclopentadienone. Cobalt-mediated cyclooligomerization of mono- and di(6-azulenyl)acetylenes afforded 1,3,5- and 1,2,4-tri(6-azulenyl)benzene derivatives together with (eta(5)-cyclopentadienyl)[tetra- and di(6-azulenyl)cyclobutadiene]cobalt complexes. The redox behavior of these novel (6-azulenyl)benzene derivatives and [tetra- and di(6-azulenyl)cyclobutadiene]cobalt complexes was examined by cyclic voltammetry (CV). Mono(6-azulenyl)benzenes exhibited a reduction wave upon CV. In contrast, 1,2-di(6-azulenyl)benzenes showed a two-step reduction wave at the similar potential region upon CV, which revealed the formation of a dianion stabilized by 6-azulenyl substituents under electrochemical reduction conditions. Three 6-azulenyl substituents on benzene in a 1,2,4 relationship also increased electron-accepting properties because of the formation of a closed-shell dianionic structure, whereas 1,3,5-tri(6-azulenyl)benzenes were reduced stepwise.

Journal Article↗
PubMed2001

Tandem transesterification and intramolecular cycloaddition of alpha-methoxycarbonylnitrones with chiral acyclic allyl alcohols: systematic studies on the factors affecting diastereofacial selectivity of the cycloaddition.

Factors affecting the stereochemical course of the intramolecular cycloaddition of intermediary alpha-allyloxycarbonylnitrone resulting from transesterification of alpha-methoxycarbonylnitrones 1a-d with chiral allyl alcohols 5 or 6 were investigated systematically. It was found that the factors of diastereofacial selection are highly dependent on the geometries of the allyl alcohols. In the cases where primary or secondary chiral (Z)-allyl alcohols are used, A(1,3)-strain arising from the chiralities in the (Z)-nitrone transition states of the intramolecular cycloaddtion is the most important factor. In contrast, in the case of the reaction using chiral nitrones 1c,d and (E)-allyl alcohols, steric interaction between the chiral N-substituent and the trans substituent of the olefin moiety in the intermediate is dominant. These aspects were applied to geometry-differentiated cycloaddition using a mixture of (E)-5 and (Z)-5. As a typical example, treatment of bulky 1b with a 1:1 mixture of (E)-5 and (Z)-5 in the presence of a catalytic amount of TiCl(4) and MS 4A gave 7b as the predominant product among four possible products.

Journal Article↗
PubMed2001

Synthesis, properties, and redox behavior of di(1-azulenyl)(2- and 3-thienyl)methyl cations and dications composed of two di(1-azulenyl)methylium units connected with 2,5-thiophenediyl and 2,5-thienothiophenediyl spacers.

The titled stable monocations, di(1-azulenyl)(2- and 3-thienyl)methyl cations 7a,b and 8a,b and dications composed of two di(1-azulenyl)methylium units connected with 2,5-thiophenediyl and 2,5-thieno[3,2-b]thiophenediyl spacers 9a,b and 10a,b were prepared by hydride abstraction of the corresponding methane derivatives. These mono- and dications 7a,b, 8a,b, 9a,b, and 10a,b showed high stability with large pK(R)+ values. The values of monocations 7a,b and 8a,b were 11.2-11.8 +/- 0.1 and 11.4-12.4 +/- 0.1, respectively. Two cation units in dications 9a,b and 10a,b were neutralized via one step at the pH of 11.1-11.7 +/- 0.1, which corresponds to the average of the pK(R)+ values of the dications and half-neutralized monocations. Electrochemical behavior of 7a,b, 8a,b, 9a,b, and 10a,b was examined by cyclic voltammetry (CV). Formation of the thienoquinoid products 18a,b and 19a,b from 9a,b and 10a,b was characterized by UV-vis spectroscopy under electrochemical reduction conditions. Chemical reduction of 9a,b and 10a,b with Zn powder in acetonitrile afforded 18a,b and 19a,b as deep-colored crystals, which exhibited rather high electron-donating ability.

Journal Article↗
PubMed2001

Myofascial flap without skin for intra-oral reconstruction. 1: Animal studies.

BACKGROUND: Although myofascial flaps are already used clinically in intra-oral reconstruction, the source and process of epithelialization remain unclear. METHODS: The process of epithelialization of grafted myofascia in the oral cavity was investigated using the latissimus dorsi muscle of Wistar strain rats. RESULTS: The use of myofascial tissue to fill in defects may maintain the space by preventing shrinkage and contracture of the wound, and this myofascial tissue may induce regeneration of the mucosal epithelium. Myofascia itself did not have the potential to epithelialize. Epithelialization progressed gradually along the surface of the granulated myofascia from the surrounding incised mucosal margin of the recipient site to the central portion. Immunohistochemical staining showed that keratinocyte growth factor-expressing cells were found mainly in the granulated myofascia. Within the study period, regenerated epithelium with orthokeratosis consisting of stratified squamous cells was thin and had scanty rete pegs, but it was similar to normal epithelium. CONCLUSION: Grafted myofascia in the oral cavity may play a space-making role, and induce regeneration of the mucosal epithelium, associated with the production of keratinocyte growth factor.

Animals↗
PubMed2001

Myofascial flap without skin for intra-oral reconstruction. 2: Clinical studies.

BACKGROUND: Based on the results of our animal experiment, we evaluated the clinical usefulness of myofascial graft materials in the reconstruction of intra-oral soft-tissue defects. METHODS: An axial-pattern or random-pattern myofascial flap was grafted to reconstruct oral soft-tissue defects caused by tumor resection in ten patients. A pectoralis major myofascial flap was employed in four patients, and a platysma myofascial flap was employed in six patients. RESULTS: All flaps survived, and epithelialization progressed gradually from the surrounding incised mucosal margin. Cicatricial contracture of the wound seemed to be mild and the regenerated mucosa was more flexible than skin. Because the myofascial tissue had only raw surfaces, the handling of the flaps in the oral cavity was very flexible. Moreover, cosmetically unsatisfactory scar formation and dysfunction at the donor site were mild. CONCLUSION: We feel that the myofascial graft procedure is a very useful option for the reconstruction of intra-oral soft-tissue defects, and will soon become a common procedure. We refer to this procedure as the "biological-guided mucosa regeneration (BGMR)" technique.

Adult↗
PubMed2001

Mental health of scientific researchers. I. Characteristics of job stress among scientific researchers working at a research park in Japan.

In order to clarify the characteristics of job stress in scientific researchers, a self-administered questionnaire survey for 16,330 workers was carried out at Tsukuba Research Park City, Japan. The data of 7,063 (43%) workers aged 20-59 years old were analyzed, and the characteristics of job stress in 3,290 scientific researchers were compared with those of 1,799 technicians and 1,849 clerks. The researchers perceived higher quantitative and qualitative workload, greater job control (job decision latitude), and greater reward from work, than did the other two job groups. In addition, young male researchers received a large amount of support from their coworkers, while middle-aged male researchers perceived difficulty in personal relationships with their coworkers. From the viewpoints of the demand-control-support model and the effort-reward imbalance model, the researchers, particularly men, were typically occupied in active jobs, and the large amount of effort required for their work seemed to be balanced by greater reward from work. Compared with male researchers, however, female researchers perceived lesser job demand, lesser job control, and lesser reward from work. The working environment of female researchers may be related to the so-called career stress of working women. The mental health status of these scientific researchers should be examined directly in a future study.

Adult↗
PubMed2001

Noninvasive quantitative tissue characterization and two-dimensional color-coded map of human atherosclerotic lesions using ultrasound integrated backscatter: comparison between histology and integrated backscatter images.

OBJECTIVES: The purpose of the present study was to define clinicopathologically whether integrated backscatter (IB) combined with conventional two-dimensional echo (2DE) can differentiate the tissue characteristics of calcification (CL), fibrosis (FI), lipid pool (LP) with fibrous cap, intimal hyperplasia (IH) and thrombus (TH) and can construct two-dimensional tissue plaque structure in vivo. BACKGROUND: It is difficult to characterize the components of plaque using conventional 2DE techniques. METHODS: Integrated backscatter values of plaques were measured in the right common carotid and femoral arteries (total 24 segments) both during life and after autopsy in 12 patients (age 68 to 84 years, 10 men and two women). Integrated backscatter values were determined using a 5-12 MHz multifrequency transducer, setting the region of interests (ROIs) (11 x 11 pixels) on the echo tomography of the entire arterial wall (55 +/- 10 ROI/segment) and comparing it with histologic features in the autopsied arterial specimens. RESULTS: Corrected IB values obtained before death and at autopsy were significantly correlated (r = 0.93, p < 0.01). Corresponding to the histologic features, corrected IB values on the rectangle ROIs obtained during life were divided into five categories: category 1 (TH) 4 < IB < or = 6; category 2 (media and IH or LP in the intima) 7 < IB < or = 13; category 3 (FI) 13 < IB < or = 18, category 4 (mixed lesion) 18 < IB < or = 27 and category 5 (CL) 28 < IB < or = 33. In category 2, media and intima were differentiated using conventional 2DE. Under the above procedures, color-coded maps constructed with IB-2DE obtained during life precisely reflected the histologic features of media and intima. CONCLUSIONS: Integrated backscatter with 2DE represents a useful noninvasive tool for evaluating the tissue structure of human plaque.

Aged↗
PubMed2001

Influence of acyl chain lengths in mono- and diacyl-sn-glycerophosphatidylcholine on gelatinization and retrogradation of starch.

The influence of starch with 1- or 2-monoacyl-sn-glycerophosphatidylcholine (GPC) having various chain lengths of fatty acids on gelatinization and retrogradation of starch was studied by the measurement of starch-GPC complex formation, complexing index, and differential scanning calorimetry. The addition of GPC to the starch sample slightly increased the blue value and lambda(max) with increasing chain length of GPC but decreased the phosphorus content and complexing index. The gelatinization onset and peak temperatures of starch complexes increased significantly with increasing chain length, but the enthalpies were statistically lower, except for the treatment with 1,2-distearoyl-sn-GPC when compared with that of the control. Among GPC (di and mono), 1- and 2-monomyristoyl-sn-GPC showed the highest complexing ability, whereas the complexing ability of the GPC decreased with the increasing chain length. According to the Avrami equation, the retrogradation rate (k, day(-1)) of starch was slower than that of the control, whereas the retrogradation rates of 1- and 2-monomyristoyl-sn-GPC were slowest among the GPCs. The positive linear relationship between k and the number of acyl groups of GPC suggests that a GPC with a shorter chain length could retard the retrogradation of starch during storage.

Calorimetry, Differential Scanning↗
PubMed2001

Sociodemographic and clinical characteristics of psychiatric patients coercively brought to hospitals.

In order to clarify the sociodemographic and clinical characteristics of psychiatric patients with poor motivation for treatment, we examined patients who were coercively brought to hospitals. Sociodemographic and clinical data on 287 inpatients from two private psychiatric hospitals in Japan were retrospectively analyzed. All patients were in the hospitals on 1 April 1997 and had received treatment prior to this admission. Of these inpatients, 67 (23.3%) were coercively brought to hospitals. Multiple logistic regression was performed on the data of these patients to identify the factors associated with their resistance to visiting the hospital. From the results of multivariate analysis, four characteristics were associated with patients coercively brought to hospitals, namely medication compliance, receiving regular outpatient treatment or not, a history of self-aggression or aggressive behavior towards others, and living arrangements. For patients who had lived with relatives before hospitalization, the primary caregiver being a parental caregiver was associated with patients coercively brought to hospitals, although it was not statistically significant. In addition, agitation was associated with patients not coercively brought to the hospital according to multivariate analysis. The present results suggest that psychiatric patients with poor motivation are more likely to have poor medication compliance, to have not received regular outpatient treatment, to have a history of aggressive behavior and to live alone. For patients who lived with their caregivers prior to hospitalization, poorly motivated patients tended to have parental caregivers and were less likely to be agitated.

Adult↗
PubMed2001

Characterization of the gene encoding the beta-lactamase of the psychrophilic marine bacterium Moritella marina strain MP-1.

The beta-lactamase gene (mbla) of the psychrophilic marine bacterium Moritella marina strain MP-1 was identified in a previously isolated genomic DNA fragment and it was expressed in Escherichia coli cells. The mbla gene encoded a protein consisting of 287 amino acid residues. Its predicted amino acid sequence showed approximately 50% identity with that of a number of class A beta-lactamases, especially with that of CARB/PSE type of beta-lactamases (carbenicillinases). E. coli transformed with the plasmid containing mbla grew on an ampicillin-containing plate at 37 degrees C but not at 42 degrees C, suggesting that the beta-lactamase of this bacterium is heat-labile.

Amino Acid Sequence↗
PubMed2001

Functional characterization of rat organic anion transporter 2 in LLC-PK1 cells.

Rat organic anion transporter 2 (rOat2) is abundantly expressed in the liver and localized to the basolateral membrane. A previous study using the Xenopus laevis oocyte expression system has shown that rOat2 transports organic anions such as salicylate () and, in the present study, rOat2 was characterized using a mammalian expression system. In addition to the substrates previously shown to be transported by rOat2, three substrates, indomethacin [IDM, Michaelis-Menten constant (K(m)) of 0.37 microM] and nucleoside derivatives such as 3'-azido-3'-deoxythymidine (AZT, K(m) of 26 microM) and 2',3'-dideoxycytidine (ddC, K(m) of 3.08 mM), were also identified for the first time The rank order of rOat2-mediated transport of these substrates was IDM > salicylate > prostaglandin E(2) > AZT > ddC > p-aminohippurate (PAH). Ketoprofen, indocyanine green and glibenclamide are potent inhibitors of the uptake of [(14)C]salicylate via rOat2 (K(i) of approximately 12 microM), while diclofenac, benzoate, verapamil, ibuprofen, and tolbutamide are moderate inhibitors (K(i) of approximately 150 microM). The affinity of PAH, a common substrate for the OAT family, for rOat2 is low (K(i) > 1 mM) compared with the other members of the OAT family (rOat1 and rOat3). Salicylate and IDM are also substrates for rOat1, but their affinity for rOat2 was higher than that for rOat1. The present study shows that rOat2 is a multispecific transporter and suggests that it may be involved at least partly, in the hepatic uptake of IDM, salicylate and nucleoside derivatives.

Algorithms↗
PubMed2000

Considerable time from the onset of plaque rupture and/or thrombi until the onset of acute myocardial infarction in humans: coronary angiographic findings within 1 week before the onset of infarction.

BACKGROUND: It has been thought that the thrombi and bleeding in plaques that occur after plaque rupture or endothelial damage from vessels with mild stenosis suddenly occlude the lumen and cause acute myocardial infarction (AMI). However, our hypothesis is that thrombi and bleeding may not suddenly occlude the lumen. METHODS AND RESULTS: The study group consisted of 20 patients who had coronary angiograms performed within 1 week (3+/-3 days) before AMI and 20 control patients who had coronary angiograms performed 6 to 18 months (282+/-49 days) before AMI. The features of infarct-related coronary segments (IRCS) at 3 days before AMI were the presence of a significant stenosis of >50% (95% in incidence and 71+/-12% diameter stenosis) and Ambrose's type II eccentric lesions (plus multiple irregularities), an indicator of plaque rupture and/or thrombi (60% [70%]), and the features at 1 year before AMI were mild stenosis of <50% (95% incidence and 30+/-18% diameter stenosis) with rare Ambrose's type II eccentric lesions (plus multiple irregularities) (10% [10%]). The same relation was observed in each of the 4 subgroups with Q-wave infarction, non-Q-wave infarction, preceding effort angina within 1 month before AMI, and no preceding effort angina. CONCLUSIONS: The appearance of marked progression and Ambrose's type II eccentric lesion on coronary angiograms 3 days before AMI suggests the presence of a considerable time from the onset of plaque rupture and/or thrombi until the onset of AMI. These features may be predictors of AMI. The concept provides new insight into the mechanism and prevention of human AMIs.

Acute Disease↗