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Biomedical subjects

I Hashimoto

Publications and source records attributed to I Hashimoto.

At least 37 records · Page 2Linked to original sources
PubMed1989

Sensory nerve action potentials elicited by mechanical air-puff stimulation of the index finger in man.

Brief air-puff stimuli were applied to the tip of the index finger to record propagating sensory nerve action potentials (APs) from pairs of surface electrodes at successive sites over the median nerve of the distal forearm. Within 10 msec, air-puff stimulation elicited 2-4 separate waves lasting 3-6 msec, in contrast to a single triphasic wave evoked by electrical stimulation. Amplitudes of air-puff evoked APs were much smaller than those of electrically induced APs. However, the amplitude ratio of the initial negative wave (P1-N1) of electrically evoked APs to that of air-puff induced APs declined linearly as a function of recording points along the ascending median nerve. Similarly, the duration ratio of the same component (N1) increased progressively in the proximal direction along the nerve. These results suggest that air-puff evoked afferent volleys undergo considerably less temporal dispersion than those induced by electrical stimulation. Thus, each peak of air-puff evoked APs represents a relatively homogeneous afferent fiber population. The initial P1, N1 and P2 peaks of air-puff evoked APs occurred later than those of electrical induced APs, and the latency included the time of skin indentation and receptor transduction in response to mechanical stimulation. Proximal conduction velocities were faster than distal conduction velocities due to cancellation of the extra delay at the skin mechanoreceptors as well as a true increase in the proximal direction. There were no significant differences between the interelectrode conduction velocities of the fastest fibers activated by the air-puffs and by electrical stimulation. Interelectrode propagation velocities of the different peaks from the same segments had no significant differences for air-puff evoked APs. The presence of multiple peaks may not be the result of temporal dispersion due to difference in conduction velocity of skin afferents but primarily due to a more peripheral receptor mechanism involving transduction and impulse generation.

Action Potentials↗
PubMed1989

Superoxide anion in polymorphonuclear leukocytes of hairless rats suffering from magnesium-deficiency dermatitis.

Clinical and histological studies were made on magnesium-deficiency dermatitis produced on a new strain of hairless rats. Superoxide anion generation in polymorphonuclear leukocytes (PMNs) and the inhibitory effect of some antioxidants and anti-inflammatory agents against the elicited dermatitis were also examined. From the detection of increased superoxide production and effective actions of inhibitors including superoxide dismutase, cepharanthine, 4-4'-diamono-diphenylsulphone and 5,4,11,14-eicosatetraynoic acid (ETYA), it is indicated that superoxide anion or related activated oxygen may be responsible for magnesium-deficiency dermatitis as an inflammatory mediator and that the dermatitis may be related to lipoxygenase metabolites derived from arachidonic acid.

Animals↗
PubMed1989

[Changes in cerebral level of monoamines by Japanese encephalitis virus infection].

The changes in monoamine levels of different brain regions following Japanese encephalitis virus (JEV) intraperitoneal inoculation were examined in experimentally JEV-infected mice. In addition, virus distribution was studied using infectivity assay and immuno-histochemistry of viral antigen. 1) The level of monoamines in brain tissues was not affected by 48 hours after viral inoculation, but marked effects were elicited at 96 hours after the inoculation. The cerebral concentration of 5-hydroxyindole-3-acetic acid (5 HIAA) was increased, while that of dopamine (DA) showed a decrease. Especially these alteration were observed in the cerebral cortex, but not in the cerebellum. 2) The viral growth in the brain was observed at 48 hours after the inoculation. The growth in the cerebellum, however, was found to be lower than those in other cerebral regions. 3) The viral antigen was detected in the cerebral cortex, hippocampus, mesencephalon and diencephalon in addition to the substantia nigra and striatum. From these results, it is presumed that clinical manifestation of JEV infection may involve the changes in the metabolism of neurotransmitter, especially those of DA and serotonin in the brain.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1989

A new model of bacterial peritonitis in mice for evaluation of antibiotics. Effects of aspoxicillin and piperacillin.

Experimental peritonitis was produced in mice with Escherichia coli TPRL 10760 derived from the intestinal flora of mouse and used to evaluate the chemotherapeutic effects of semisynthetic penicillins, aspoxicillin (ASPC) and piperacillin (PIPC). The peritonitis was induced by inserting a gelatin capsule containing the bacterial cells, sterilized cecal contents and BaSO4 into the pelvic cavity of an anesthetized mouse. Infection with more than 10(6) colony forming units (CFU) of the bacteria/mouse resulted in an acute peritonitis associated with 100% mortality, whereas an inoculum size of 10(2) CFU/mouse produced a chronic peritonitis. In the mice with acute peritonitis, administration of 100 mg/kg x 5 times of ASPC reduced the mortality to 0% but administration of 100 mg/kg x 5 times of PIPC did not reduce the mortality. In the mice with chronic peritonitis, ASPC was more effective than PIPC in decreasing the number of viable bacterial cells in the peritoneal fluid. The superiority of ASPC over PIPC was attributable to its higher bactericidal activity as well as its high drug level and more persistency in the peritoneal fluid as compared to PIPC.

Amoxicillin↗
PubMed1988

Trigeminal evoked potentials following brief air puff: enhanced signal-to-noise ratio.

Trigeminal somatosensory evoked potentials (TSEPs) were studied by using fast-rising air puffs generated by a high-speed air control system. Within 100 ms, air puff stimulation of the face elicited three negative and three positive components over the contralateral, as well as the ipsilateral, sensory area. The air puff TSEPs showed a uniform change in peak latencies and amplitudes as a function of stimulus intensity. The bilateral distribution of the TSEPs stands in sharp contrast to the exclusively contralateral distribution of the SEPs to stimulation of the hand. Air puffs evoked a larger response than electrical stimulation, although the latency remained the same. Unlike electrical stimuli, air puff induces neither stimulus nor muscle artifacts. This, combined with the higher amplitude of the recorded response, enhances the signal-to-noise ratio.

Adolescent↗
PubMed1988

Somatosensory evoked potential correlates of psychophysical magnitude estimations for tactile air-puff stimulation in man.

Brief air-puff stimuli were applied to the volar surface of the right hand to obtain both psychophysical and neurophysiological responses. The detection threshold (So) was first determined (0.56 kg . cm-2 +/- 0.20 kg . cm-2, mean +/- SD) and six levels of the stimulus intensities (So + 0.25 kg . cm-2, So + 1.25 kg . cm-2, So + 2.50 kg . cm-2, So + 3.75 kg . cm-2, So + 5.00 kg . cm-2, and So + 6.25 kg . cm-2) were employed for magnitude estimation using the stimulus level of So + 2.50 kg . cm-2 as the standard stimulus. The subject was asked to estimate numerically the series of stimulus intensities randomly presented. Cortical SEPs were recorded over the hand sensory area in response to a set of 120 air-puffs at the identical intensity level. Thus SEPs for six sets of stimulus intensities given in a random order were obtained from each subject. Six components (N20, P27, N35, P45, N60, and P75) were recorded within 100 ms following stimulation. It was seen that a simple power function with an exponent of 0.81 could be an adequate description of the stimulus-response function for magnitude estimation, as was also revealed by the high correlation coefficient (r = 0.98). Similarly, stimulus-amplitude functions of different SEP components were well represented by straight lines in double logarithmic plots. The function of the early P27-N35 had the highest exponent (0.56) and also the highest correlation coefficient (r = 0.91). Plotting subjective magnitude of the abscissa produced power functions similar to the stimulus-amplitude functions. However, higher correlations were observed for later components. The amplitudes of the four earlier components correlated with stimulus intensity when the effect of subjective magnitudes was removed. In contrast, the correlation between amplitudes and subjective magnitudes with stimulus intensity held constant was positive and significant for the later three components. These results may indicate that early SEP components represent neural coding of physical intensity while later components are more closely related to the subjective judgment of the stimulus.

Adolescent↗
PubMed1988

Response of epidermolysis bullosa fibroblasts to factors derived from macrophages and polymorphonuclear leukocytes in terms of collagenase production.

In order to investigate the role of inflammatory cells in altering the collagenase production by epidermolysis bullosa (EB) fibroblasts, macrophage and polymorphonuclear leukocyte (PMN) factors obtained from mouse peritoneal fluids were added to the fibroblast culture system, and collagenase activity was assayed after a 48-h incubation. Data obtained here revealed that the response of collagenase production by fibroblasts was quite different, depending on the type of EB. Namely, EB dystrophica recessiva (EBDR) (n = 2) fibroblasts produced significant amounts of collagenase in the range of 5.07 (U/ml) to 6.04 in response to macrophage-conditioned medium, macrophage lysate, and PMN lysate, compared with 0.13 in the absence of these. On the other hand, EB dystrophica dominans (EBDD) (n = 1) fibroblasts showed little or no overt increase in enzyme production in the presence of macrophage lysate and PMN lysate, which resulted in a moderate increase to 3.82 in response to macrophage-conditioned medium. Furthermore, EB simplex (EBS) (n = 1) fibroblasts produced collagenase up to 3.84 in response to these three factors. These factors can be inactivated by treating with trypsin, pronase, and phenylglyoxal. Our data clearly indicated that, in the comparisons of EBDD and EBS fibroblasts, EBDR fibroblasts showed quite high response to factors derived from macrophages and PMNs in terms of collagenase production. This fact may raise a clue that accounts for the high levels of tissue collagenase activity, which plays a potentially major role in blister formation in EBDR.

Animals↗
PubMed1988

[Clinical evaluation of cefpodoxime proxetil in the treatment of skin and soft tissue infections. A double blind comparison of cefpodoxime proxetil and cefaclor].

In order to objectively evaluate the effectiveness, safety and usefulness of the new oral cephem cefpodoxime proxetil (CS-807, CPDX-PR) for the treatment of skin and soft tissue infections, a double-blind comparative study was undertaken using cefaclor (CCL) as the control drug. CPDX-PR and CCL were administered for 7 days at daily doses of 400 mg (divided into 2 portions) and 750 mg (divided into 3 portions), respectively. A total of 243 patients (118 in the CPDX-PR group and 125 in the CCL group) was treated in this study. The effectiveness, safety and usefulness were evaluated in 222 (106 in the CPDX-PR group and 116 in the CCL group), 234 (113 in the CPDX-PR group and 121 in the CCL group) and in 223 patients (107 in the CPDX-PR group and 116 in the CCL group), respectively. There were no differences in patients' backgrounds between the 2 groups, except for the presence or the absence of surgical treatments. The results we obtained are summarized below: 1. In the evaluation of clinical efficacy by the subcommittee, excellent, good, fair and poor efficacy were observed in 36, 43, 17 and 10 patients in the CPDX-PR group, respectively; the efficacy rate was, therefore, calculated to be 74.5%. As for the CCL group, respective results were observed in 50, 39, 17 and 10 patients, indicating an efficacy rate of 76.7%. There was no significant difference between the 2 groups. Improvement rates judged by physicians in charge were 80.2% in the CPDX-PR group and 88.8% in the CCL group. Moreover, no significant difference in diseases or severity were found between the 2 groups. 2. As for the bacteriological efficacy, the 2 groups showed high elimination rates, as 90.1% and 91.6% of the disease causing bacteria were eliminated in the CPDX-PR group and in the CCL group, respectively. Elimination rates in single infections with Staphylococcus aureus were determined to be 85.7% in the CPDX-PR group and 85.0% in the CCL group. 3. Although 6 patients in the CPDX-PR group and 2 patients in the CCL group developed side effects, which were mainly gastrointestinal symptoms, there was no significant difference in the incidence of side effects between the 2 groups. Abnormal laboratory values were found in 5 patients in the CPDX-PR group and 1 patient in the CCL group. 4. There was no significant difference in the usefulness between the 2 groups.(ABSTRACT TRUNCATED AT 400 WORDS)

Abscess↗
PubMed1987

Somatosensory evoked potentials elicited by air-puff stimuli generated by a new high-speed air control system.

Sharp-fronted air-puffs (a rise-time of 1 msec) generated by the new high-speed air control system were used for eliciting SEPs. This system employs a rotating disk driven by a synchronous electric motor for high-speed control of air flow from a compressed air source. The air-puff is reproducible and its pressure wave form can be varied. SEPs to air-puffs or electrical stimulations of the right hand recorded from the contralateral parietal scalp had similar wave forms, but SEPs to air-puffs showed longer latencies (1-4 msec) and smaller amplitudes than those to electrical stimuli. The amplitude of early components in air-puff SEPs was on average 30% of that in electrical SEPs, but later components reached up to about 90%.

Adolescent↗
PubMed1987

Preovulatory secretion of progesterone, luteinizing hormone, and prolactin in 4-day and 5-day cycling rats.

Timing of ovulation and changes in plasma progesterone, luteinizing hormone (LH), and prolactin (PRL) during periovulatory stages were determined in Holtzman rats exhibiting regular 4- or 5-day cycles under a daily artificial illumination from 0500 to 1900 h. The 5-day cycling rats ovulated between 0130 and 0930 h on estrus, whereas some of the 4-day cycling animals ovulated as early as about 0130 h and others as late as 1130 h on estrus. Onset time of preovulatory LH and progesterone surges was about 1500 h on proestrus in both the 4- and the 5-day cycling rats. Peak levels of plasma LH and progesterone were measured at 1700 to 1900 h on proestrus, while the first rises and peak values of plasma PRL were evident a few hours earlier than those of plasma LH in the rats with two cycle lengths. Plasma LH levels at 1900 h on proestrus as well as plasma progesterone levels at 1600 and 2300 h on proestrus and at 0130 and 0330 h on estrus were significantly lower in the 5-day cycling rats than in the 4-day cycling animals (p less than 0.05). In contrast, PRL levels from 1500 through 2300 h on proestrus remained consistently higher in 5-day cycling rats than in 4-day cycling rats, and significant differences in PRL levels between these rats were apparent at 1500, 1600, and 2100 h (p less than 0.05-0.01). Thus, these results demonstrate that the 5-day cycling rats exhibit the attenuated magnitude of LH surge accompanied by the augmented preovulatory PRL release, and that plasma progesterone levels reflect the magnitude of LH surge. A tentative working hypothesis concerning the etiology of the 5-day cycle has been proposed.

Animals↗