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Biomedical subjects

M Mimura

Publications and source records attributed to M Mimura.

At least 37 records · Page 2Linked to original sources
PubMed1998

Memory for subject performed tasks in patients with Korsakoff syndrome.

We examined the ability of alcoholic Korsakoff patients to remember verbal and action-related information. Eight Korsakoff patients and eight alcoholic control subjects learned action phrases in either subject-performed tasks (SPTs) or verbal tasks (VTs). Free recall and recognition tests were then administered. Despite the severe anterograde amnesia observed in Korsakoff patients for VTs, their memory performance for SPTs was similarly facilitated over VTs as was the case with alcoholic controls. Domains preserved in this amnesic syndrome may account for the benefit seen when using SPTs in Korsakoff patients. The therapeutic utilization of action events for memory rehabilitation is discussed.

Adult↗
PubMed1998

Anti-MRSA activity of sophoraflavanone G and synergism with other antibacterial agents.

Anti-MRSA activity of sophoraflavanone G (SFG) and synergism between SFG and antibacterial agents against MRSA (methicillin-resistant Staphylococcus aureus) were evaluated by means of Minimal Inhibitory Concentrations (MIC). The MICs of SFG against 27 strains of MRSA ranged from 3.13 to 6.25 micrograms ml-1. Synergism between SFG and vancomycin hydrochloride (VCM) or fosfomycin (FOM) was observed (the fraction inhibitory concentration (FIC) indices were 0.16 and 0.48), while partial synergism was admitted between SFG and other antibacterial agents such as methicillin (DMPPC), cefzonam (CZON), gentamicin (GM), minocycline (MINO) and levofloxacin (LVFX) (the FIC indices were 0.71, 0.73, 0.69, 0.65 and 0.58, respectively). These findings suggest that SFG in combination with VCM or FOM may be useful in controlling MRSA infections.

Anti-Bacterial Agents↗
PubMed1998

Prospective and retrospective studies of recovery in aphasia. Changes in cerebral blood flow and language functions.

Prospective and retrospective language evaluations and single photon emission computed tomography (SPECT) scans were performed in order to study the relationship between post-stroke recovery from aphasia and changes in cerebral blood flow (CBF) in groups of patients who had made a good recovery and those who had not. For the prospective study, 20 right-handed patients with aphasia secondary to an acute cerebrovascular accident (CVA) in the left middle cerebral artery territory received language evaluations with a Japanese Standard Language Test of Aphasia (SLTA), and SPECT scans performed twice, at a mean of 3.2 and a mean of 9.2 months post-onset. Only one slice of SPECT data was analysed. A significant correlation was observed between the severity of the initial language deficit and initial CBF on the left side, but not the right. Initial CBF was not a predictor for future language recovery in either hemisphere. There was a correlation between the change in the left mean hemispheric CBF (but not the right) and the change in the overall SLTA severity rating from 3 to 9 months post-stroke. In the retrospective study, 16 right-handed patients with residual aphasia secondary to CVA in the left middle cerebral artery territory received SLTA and SPECT at a mean of 82.8 months post-onset. The patients had also received initial language evaluation with SLTA at a mean of 6.5 months post-onset. In contrast to the prospective study, the results demonstrated that the mean left hemispheric CBF at approximately 7 years post-onset did not differ between good and poor recovery groups. However, the mean right hemispheric CBF of the good recovery group was higher than that of the poor recovery group in the frontal and the thalamic regions, and also in the left frontal region. The results of these complementary studies suggest that the initial language recovery within the first year post-onset may be linked primarily to functional recovery in the dominant hemisphere, where an increase in CBF was observed at 9 months post-onset. The increased perfusion adjacent to the lesion may be crucial for early recovery in aphasia. Subsequent language recovery and the long-term recovery in aphasia may be related to slow and gradual compensatory functions in the contralateral hemisphere, specifically in the homotopic frontal and thalamic areas.

Adult↗
PubMed1998

[Postoperative hypoxia and hyperfibrinolysis in patients after total knee replacement].

It was revealed that postoperative hypoxia had occurred frequently in patients after total knee replacement (TKR) in our preliminary study. Since we speculated that pulmonary embolism was the cause of the hypoxia, we investigated the relationship between PaO2 and D-dimer in patients after TKR and high tibial osteotomy (HTO). A total of 13 patients with the diagnosis of osteoarthritis were studied. Ten patients underwent TKR and three received HTO under subarachnoid block. Arterial oxygen tension and D-dimer were unchanged in patients who had undergone HTO. Even on the 5th postoperative day, five of the ten patients after TKR revealed a decrease in oxygen tension by more than 10% compared with the preoperative control (hypoxia group). In the other patients after TKR, a decrease of oxygen tension on the 5th postoperative day was under 10% (non-hypoxia group). There was a positive correlation between a decrease of PaO2 and a value of D-dimer in all of the patients who had undergone TKR and HTO. Although no patient developed dyspnea clinically, one patient in hypoxia group was diagnosed as pulmonary embolism in the scintigram. It is likely that pulmonary embolism is the cause of postoperative hypoxia in patients after TKR.

Aged↗
PubMed1998

[Positive end-expiratory pressure facilitates washout of nitrous oxide in patients with obstructive pulmonary disease].

This study was designed to investigate the relationship between nitrous oxide elimination and each value of pulmonary function tests: percent vital capacity, air way resistance and percent of forced expiratory pressure (FEV1.0%) in patients undergoing general anesthesia. Furthermore, the effect of positive end-expiratory pressure (PEEP) on nitrous oxide elimination was studied. Thirty nine patients, anesthetized by oxygen, nitrous oxide and sevoflurane, were allocated randomly to one of two groups; one, with PEEP 10 cmH2O during nitrous oxide elimination and the other, without. After discontinuation of nitrous oxide, the concentration of nitrous oxide was measured at 15 sec intervals under controlled ventilation with 100% oxygen-sevoflurane. There was a significant correlation between nitrous oxide washout time and FEV1.0% (P < 0.05). Patients were further divided into two subgroups: FEV1.0% of over 70% (normal FEV) and that of less than 70% (low FEV). In the normal FEV group, the washout time was unaffected by PEEP. In the low FEV group, the washout times, with and without PEEP, were 7.07 +/- 0.93 min and 9.13 +/- 2.32 min, respectively. The difference was significant (P < 0.05). These results suggest that patients with chronic obstructive lung disease are at risk of delay in nitrous oxide elimination. This delay was found to be preventable with PEEP.

Aged↗
PubMed1998

[Regional cerebral blood flow and oxygenation following cervicothoracic sympathetic block].

Stellate ganglion block (SGB) is considered to increase blood flow to the governing area, but recent studies have shown the decrease of common carotid arterial blood flow in the unblocked side following SGB. We investigated the influence of SGB on bilateral cerebral blood flow and oxygenation using a regional oxygen saturation (rSO2) monitor, TOS-96 (TOSTEC, Japan). The changes of blood volume (hemoglobin index: Hb I) and rSO2 were measured in twenty adult patients who underwent SGB at the transverse process of the C 6 vertebra. Prior to the investigation, two sensors were calibrated and placed on either side of each patient's forehead in order to see the difference. There were significant increases in rSO2 and Hb I in the blocked side and decreases in rSO2 and Hb I in the contralateral side. These results suggest that blood flow in the blocked side following SGB increases with decreased blood flow in the unblocked side. Patients with cerebral vascular disease undergoing SGB might be at risk of a decrease in cerebral blood flow in the unblocked area.

Adult↗
PubMed1997

Cytochrome P450-dependent drug oxidation activities in liver microsomes of various animal species including rats, guinea pigs, dogs, monkeys, and humans.

Levels of cytochrome P450 (P450 or CYP) proteins immunoreactive to antibodies raised against human CYP1A2, 2A6, 2C9, 2E1, and 3A4, monkey CYP2B17, and rat CYP2D1 were determined in liver microsomes of rats, guinea pigs, dogs, monkeys, and humans. We also examined several drug oxidation activities catalyzed by liver microsomes of these animal species using eleven P450 substrates such as phenacetin, coumarin, pentoxyresorufin, phenytoin, S-mephenytoin, bufuralol, aniline, benzphetamine, ethylmorphine, erythromycin, and nifedipine; the activities were compared with the levels of individual P450 enzymes. Monkey liver P450 proteins were found to have relatively similar immunochemical properties by immunoblotting analysis to the human enzymes, which belong to the same P450 gene families. Mean catalytic activities (on basis of mg microsomal protein) of P450-dependent drug oxidations with eleven substrates were higher in liver microsomes of monkeys than of humans, except that humans showed much higher activities for aniline p-hydroxylation than those catalyzed by monkeys. However, when the catalytic activities of liver microsomes of monkeys and humans were compared on the basis of nmol of P450, both species gave relatively similar rates towards the oxidation of phenacetin, coumarin, pentoxyresorufin, phenytoin, mephenytoin, benzphetamine, ethylmorphine, erythromycin, and nifedipine, while the aniline p-hydroxylation was higher and bufuralol 1'-hydroxylation was lower in humans than monkeys. On the other hand, the immunochemical properties of P450 proteins and the activities of P450-dependent drug oxidation reactions in dogs, guinea pigs, and rats were somewhat different from those of monkeys and humans; the differences in these animal species varied with the P450 enzymes examined and the substrates used. The results presented in this study provide useful information towards species-related differences in susceptibilities of various animal species regarding actions and toxicities of drugs and xenobiotic chemicals.

Adrenergic beta-Antagonists↗
PubMed1997

Dry eye and Meige's syndrome.

AIMS: To determine the relation between dry eye and Meige's syndrome. METHODS: 325 patients with dry eye were divided into those responsive to topical and other forms of treatment (n = 276) and those who were not (n = 49). A neuropsychiatric examination was performed to check for Meige's syndrome in the latter group. RESULTS: Twenty eight (57%) of the treatment unresponsive patients were diagnosed with Meige's syndrome. CONCLUSIONS: There is a subgroup of patients with dry eye who do not respond to simple therapy. More than half of these patients have Meige's syndrome and need psychiatric, as well as ophthalmic, care.

Adult↗
PubMed1997

Corticobasal degeneration: neuropsychological and clinical correlates.

A comprehensive neuropsychological test battery was administered to 3 patients who met the clinical criteria of corticobasal degeneration (CBD). The pattern of neuropsychological deficits in CBD appears to be a distinctive mixture of posterior cortical dysfunction and frontal-subcortical system impairment.

Aged↗
PubMed1997

Polysaccharide of Astragali radix enhances IgM antibody production in aged mice.

The effect of Astragali Radix (AR) on IgM antibody production in mice of various ages (10 weeks, 36 weeks and 60 weeks) was examined. The antibody production levels in the 36- and 60-week-old mice were significantly decreased to about 70 and 60% of that in the 10-week-old mice. The enhancement effect of a crude polysaccharide AR fraction on the antibody production was nil in the 10-week-old mice, but significant enhancement effects were observed in the 36- and 60-week-old mice, compared to the age-matched control. Two polysaccharides active in the enhancement of the IgM antibody production in the aged mice were isolated from the high molecular weight fraction of AR by cetavlon precipitation, ion-exchange and gel permeation chromatography. The molecular masses of these polysaccharides were calculated by HPLC in salt solution. Only one major peak was observed for each, and their molecular masses were estimated to be 1.2 x 10(4) and 2.2 x 10(4). The major components of these polysaccharides were neutral carbohydrates (89.3 and 95.5%), followed by uronic acid and protein; glucose was the predominant sugar component.

Aging↗
PubMed1997

Repetition priming in an auditory lexical decision task: effects of lexical status.

The effect of lexical status on the time course of repetition priming was examined in an auditory lexical decision task. Words and nonwords were repeated at lags of 0, 1, 4, and 8 items (Experiment 1A) and 0, 2, 4, and 8 items (Experiment 1B). The pattern of repetition effects differed for words and nonwords in that repetition priming for nonwords at lag 0 was significantly greater than for words. The magnitude of this effect decreased when one or more items intervened. A second experiment, replicating Experiment 1A with visual presentation, clarified that the greater magnitude of repetition priming for nonwords at lag 0 is unique to the auditory modality. This finding suggests that in the course of forming a stable perceptual representation, the details of the acoustic/phonological information of an auditory stimulus are more readily available for nonwords than for words. The capacity to carry this phonological information is limited, however, and can only be maintained until another stimulus is encountered.

Adult↗
PubMed1997

[A semantic-pragmatic learning disabled child who showed a discrepancy between the abilities of verbal and non-verbal comprehension].

A learning disabled (LD) child with disorder of verbal semantic comprehension was reported. This case showed normal ability of non-verbal semantic comprehension. He was not able to understand the meaning of what he read aloud and/or repeated, which he did well. The focus of his brain dysfunction in the left temporal lobe was revealed by SPECT in spite of MRI findings of no particular lesions. Neuropsychological and cognitive-psychological findings were similar to those reported of adult sensory aphasias with localized lesions.

Child↗
PubMed1997

[Autobiographical memory loss following herpes encephalitis].

We report a patient with prominent autobiographical memory (ABM) impairment, and discussed possible mechanisms of her deficits. The patient was a 36-year-old woman who suffered from herpes simplex encephalitis in November 1994. Four months after the onset, the neuropsychological examination disclosed that her intelligence, attention, language and frontal lobe functions were normal. Moderate anterograde amnesia was evident for visual materials, and she showed difficulties in retrieving visual images. Deficits in verbal learning were minimal. In contrast, her retrograde amnesia (RA) was severe. Further analyses clarified that memory for public events and personal semantic memory were relatively well preserved whereas ABM was severely impaired with no evidence of temporal gradient. Her performance on the ABM questionnaire was even worse than that of alcoholic Korsakoff patients. Interestingly, however, deficits in memory for public events also emerged when questions were presented with pictures instead of ordinary verbal questionnaires. The results suggest that her principle deficits consisted in utilizing visual information of the past events. Her access to and manipulation of the past visual representation/images were impaired. Consequently, her deficits were almost exclusive to ABM because visual information is most crucial for ABM. This material specific ABM impairment demonstrated in the present patient could be differentiated from nonspecific retrograde amnesia observed in typical focal RA patients. MRI, SPECT and PET demonstrated that the present patient had lesions basically in the right hemisphere, specifically in the medical temporal area including the hippocampus.

Adult↗
PubMed1996

Conformation of cyclic and linear (1 --> 2)-beta-D-glucans in aqueous solution.

The conformations of cyclic (1 --> 2)-beta-D-glucan chains having degree of polymerization (dp) 17 to 24 were characterized by means of small-angle X-ray scattering and Monte Carlo simulation. The results indicate that cyclic (1 --> 2)-beta-D-glucan chains adopt the shape of a doughnut-like ring with a thickness of about 10 A for all the samples. The diameter of the annulus for the cyclic glucan having dp 21 is estimated to be only about 4-5 A. Two linear (1 --> 2)-beta-D-glucans possessing dp 19 and 21 prepared by acid hydrolysis of a cyclic glucan and subsequent fractionation showed different scattering profiles from those obtained for cyclic glucans having the corresponding dp. Although the Monte Carlo simulation does not completely reproduce the scattering profiles observed by small-angle X-ray scattering, linear (1 --> 2)-beta-D-glucans seem to possess a characteristic cylindrical shape with cross-sectional diameters of 11.8 and 13.2 A for linear glucans of dp 19 and 21, respectively.

Chromatography, High Pressure Liquid↗
PubMed1996

7-Ethoxycoumarin O-deethylation catalyzed by cytochromes P450 1A2 and 2E1 in human liver microsomes.

7-Ethoxycoumarin O-deethylation has been used widely as a marker activity for assessing substrate specificities of cytochromes P450 (P450) in liver microsomes of mammals, and extensive studies have shown that in rats and mice the major catalysts are P450 1A1, 1A2, and 2B enzymes. In contrast to findings in experimental animal models, P450 2E1 has been reported to be a principal enzyme involved in 7-ethoxy-coumarin O-deethylation in human livers. In this study, we further examined the roles of individual forms of human P450 involved in 7-ethoxycoumarin O-deethylation using microsomes from different human liver samples and from human lymphoblastoid cells expressing human P450 enzymes and purified P450 enzymes isolated from the membrane of Escherichia coli expressing modified P450 proteins. Kinetic analysis showed that there were at least two different enzymes involved in 7-ethoxycoumarin O-deethylation in different human samples. Samples that contained high amounts of P450 2E1 in liver microsomes showed biphasic curves for O-deethylation with relatively high turnover numbers, whereas P450 1A2-rich samples tended to have low Km values with low Vmax values. Anti-human P450 2E1 antibodies inhibited markedly (P < 0.05) the 7-ethoxycoumarin O-deethylation activities catalyzed by human liver microsomes particularly when examined at a high substrate concentration (200 microM). However, we also found that anti-P450 1A2 antibodies suppressed O-deethylation activities only at a low substrate concentration (10 microM). Recombinant human P450 1A2 was found to have a low Km value for 7-ethoxycoumarin O-deethylation, whereas P450 2E1 showed a high Km value. Of the P450 enzymes examined, P450 1A1 gave the highest O-deethylation activities with a low Km value, although this enzyme is reported to be expressed extrahepatically in humans. Other human P450 enzymes, including P450 2A6, 2C10, 2D6, 3A4, and 3A5, did not show significant O-deethylation activities except that P450 2B6, a minor P450 component in human livers, was found to have a Vmax value similar to that of P450 1A2 and a Km value similar to that of P450 2E1. These results suggest that P450 1A2 is a low Km enzyme for 7-ethoxycoumarin O-deethylation in human liver microsome, although it has a low Vmax value than P450 2E1.

7-Alkoxycoumarin O-Dealkylase↗
PubMed1996

Preserved semantic priming effect in alexia.

BH, a left-handed patient with alexia and nonfluent aphasia, was presented with a lexical-decision task in which words and pronounceable pseudowords were preceded by semantically related or unrelated picture primes (Experiment 1). In Experiment 2, BH was given an explicit reading task using the word lists from Experiment 1. Performance on Experiment 2 disclosed severe reading deficits in both oral reading and semantic matching of the words to pictures. However, in Experiment 1, BH demonstrated a significant semantic priming effect, responding more accurately and more quickly to words preceded by related primes than by unrelated primes. The present results suggest that even in a patient with severe alexia, implicit access to semantic information can be preserved in the absence of explicit identification. The possibility of categorical gradient in implicit activation (living vs. nonliving) in BH was also discussed, which, however, needs to be clarified in the further investigation.

Brain↗
PubMed1996

Histopathology of cutaneous changes in non-drug-induced coma.

To compare the histological features of non-drug-induced and drug-induced coma blister, we performed histopathological and immunopathological studies of four biopsy specimens from three patients with non-drug-induced coma. These results were compared with the previously well-documented histology of drug-induced coma. The findings of the present study of non-drug-induced coma included (a) a variable degree of epidermal cell degeneration, including vacuolation of basal cells, intraepidermal blister formation with pale cytoplasm, and extensive coagulation necrosis with pale nuclei; (b) alteration of the outer root sheath of telogen follicles, ranging from focal necrosis to total coagulation necrosis, and degeneration of sebaceous gland with disappearance of the germinative cell layer; (c) secretory eccrine cells with pyknotic nuclei, vacuolation of the cytoplasm, and intercellular edema, resulting in poorly defined cytoplasm, although the nuclei of the outer basal layer were partially preserved; (d) from slight edema of the vessel wall of the venules to fibrinoid, thrombosis and/or fibrinoid necrotic degeneration of arterioles and venules; and (e) deposits of immunoglobulins or complement as detected by direct immunofluorescent technique in all the three cases. One significant difference between non-drug-induced and drug-induced coma blister was the presence of fibrinoid thrombi in the lumina of non-drug-induced coma blisters. Since one of the three cases of non-drug-induced coma studied in the present report did not show thrombi in the lumina, this feature may not always be available for the differential diagnosis of these two conditions. However, fibrinoid thrombi may be a good marker for the differentiation of these two conditions, when the depth and duration of non-drug-induced coma are severe enough to induce these lesions.

Aged↗