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Biomedical subjects

M Murayama

Publications and source records attributed to M Murayama.

At least 19 recordsLinked to original sources
PubMed1992

Multiple gate control of the descending statocyst-motor pathway in the crayfish Procambarus clarkii Girard.

1. Synaptic responses of uropod motoneurons and interneurons to magnetic field stimulation of the statocyst were studied in a whole animal preparation using intracellular recording and staining techniques to characterize the descending statocyst pathways controlling uropod steering behavior. 2. When the animal was engaged in abdominal postural movement, all uropod motoneurons received sustained excitatory input. Motoneurons which were to be activated during steering behavior showed excitatory responses to the stimulus superimposed on the sustained excitation. In the resting state, they showed weaker responses or no visible responses to the same stimulation. 3. Motoneurons to be suppressed during steering showed inhibitory responses to the stimulus only during abdominal movement. These included both active inhibition as well as disfacilitatory suppression of excitatory input to the motoneurons. 4. Premotor nonspiking interneurons, like motoneurons, showed greater responses to the stimulus during abdominal movement than at rest. Unlike motoneurons, however, they did not always receive sustained input during abdominal movement. 5. Descending axons which responded to statocyst stimulation independent of abdominal movement were found in the 4th and 5th abdominal ganglia. Other axons showed greater responses during abdominal movement than at rest. 6. A number of intersegmental descending interneurons with cell bodies and dendrites in the 4th or 5th ganglion were found to receive excitatory inputs from both the statocyst and the motor system controlling abdominal posture. These responses were found to summate with each other to generate spikes. 7. Statocyst signals are thus transmitted to uropod motoneurons by two types of descending pathways: one whose operation is affected by the abdominal system and the other which operates independently. The former pathway functions by recruiting intersegmental abdominal interneurons and makes stronger connections with motoneurons than the latter.

Abdomen↗
PubMed1992

Verbal versus non-verbal visual evoked potentials: Kanji versus line drawings.

Cortical areas related to perception of verbal and non-verbal stimuli were studied using VEPs. Kanji characters, line drawings (LD), or a blank were displayed. Verbal VEPs were obtained by subtracting the blank-VEPs from the Kanji-VEPs, and non-verbal VEPs by subtracting the blank-VEPs from the LD-VEPs. Both the verbal and non-verbal VEPs showed a negative peak (100-300 msec) focally over bilateral occipital, posterior temporal and parietal areas, and a positive peak diffusely over frontal halves. Differences between the non-verbal from the verbal VEPs showed an initial peak (100-200 msec) focally over bilateral occipital and posterior temporal areas, followed by a peak (200-300 msec) focally over bilateral posterior temporal areas. The frontal areas diffusely showed peaks at 100-200, 200-300 and 300-400 msec. Left-right asymmetries of both the verbal and non-verbal VEPs showed peaks between 100 and 300 msec over posterior temporal, parietal, and occipital areas. Left-right asymmetries of the subtraction to the non-verbal from the verbal VEPs showed a peak (100 msec) over occipital and parietal areas, and a broader peak over posterior temporal area (100-200 msec). Bilateral occipital, posterior temporal, and parietal areas are focally activated by the two perceptions (100-300 msec), while frontal areas are activated diffusely. Further, different processes may be focally involved between the hemispheres over occipital (100-200 msec) and posterior temporal (100-200 and 200-300 msec) regions. Initial left-right asymmetries of the subtracted VEP between the two perception would occur over occipital and parietal areas (100 msec) and last for 200 msec over posterior temporal area.

Acoustic Stimulation↗
PubMed1992

Case report of primary cardiac lymphoma. The applications of PCR to the diagnosis of primary cardiac lymphoma.

A 75-year-old man initially complained of pollakiuria and low abdominal pain, and died of massive bleeding from an exacerbated gastric ulcer. The diagnosis of primary cardiac lymphoma was made postmortem. The tumor involved only the epicardium and myocardium, which met the criteria of primary cardiac lymphoma as defined by the Armed Forces Institute of Pathology. The lymphoma consisted of large cells and expressed the B cell marker, CD20. Although chronic inflammation due to chronic renal failure was observed in the pericardium around the lymphoma, polymerase chain reaction (PCR) was conducted to detect monoclonality at the DNA level in lymphoma cells, which were shown to comprise a monoclonal population.

Aged↗
PubMed1992

Long term follow-up of Cushing's disease treated with reserpine and pituitary irradiation.

Twenty adult patients with Cushing's disease treated with long term reserpine administration in combination with a single course of external pituitary irradiation were followed. Eleven patients experienced long term remissions of 15.5 +/- 8.9 (mean +/- SD) yr (55%) after a mean irradiation dose of 53.9 +/- 11.4 Gy and a mean duration of reserpine administration of 24.3 +/- 9.3 months. The long term remission rates of the patients irradiated with 50 Gy or less (n = 9; 45.0 +/- 7.1 Gy) and those with more than 50 Gy (n = 10; 61.3 +/- 3.3 Gy; excluding 1 irradiated with 66 Gy who developed brain necrosis) were 56% (5 of 9) and 60% (6 of 10), respectively, and did not differ significantly. There were no significant differences between the 2 groups with regard to the duration of reserpine administration or pretreatment clinical features. At the latest examination, regardless of the irradiation dose, all 9 patients with long term remission showed a higher level of plasma cortisol or 11-hydroxycorticosteroids in the morning than in the evening, normal suppressibility of plasma cortisol with overnight 1 mg dexamethasone (9 of 10), and well preserved responses of other pituitary hormones to various loading tests: normal responses of plasma ACTH to CRH (6 of 9), TSH (7 of 8), and PRL (5 of 8) to TRH and age-related normal responses of GH to GRH (4 of 8), LH (6 of 8), and FSH (6 of 8) to GnRH. These findings suggest that long term reserpine administration in combination with a conventional dose of pituitary irradiation is useful in the treatment of Cushing's disease.

Adolescent↗
PubMed1992

Beneficial effects of high daily dose bromocriptine treatment in Cushing's disease.

Treatment with a high daily dose bromocriptine was evaluated in 6 Cushing's disease patients (4 females and 2 males; aged 23 to 56 years). The highest doses administered were 40 mg to patient 1, 55 mg to patient 2, 35 mg to patient 3, 25 mg to patient 4, 25 mg to patient 5, and 17.5 mg to patient 6. The former 3 cases, 2 (patients 1 and 2) of whom were previously reported and further followed up, showed clinical and biochemical improvement with the regimen. Patient 1 who obtained remission with 40 mg/day has been on remission for further 14 months with a total of 36 months. Patient 2, who had a reduction in pituitary tumor size with 35 mg daily, relapsed thereafter. The therapy, however, resolved the paradoxical responses of plasma ACTH and cortisol to arginine. Readministration of bromocriptine resulted into another clinical and biochemical improvement with 45 to 55 mg/day. Patient 3, a relapsed case after a remission with reserpine plus pituitary irradiation, showed an improvement in the 24-h urinary free cortisol excretion with 35 mg/day. Patient 4 was the only case who had a marked decrease in plasma cortisol (basal; 16.3, nadir; 1.9 micrograms/dl) after a single-dose bromocriptine test among the 5 cases tested. The patient had favorable response with 25 mg/day for 2 months but the dose was not increased after an escape. Patient 5 received the drug in 4 occasions, 7.5 to 25 mg/day, in combination with several agents, which failed to induce clinical remission. The last patient did not respond to a maximum dose of 17.5 mg/day. These observations suggest that, regardless of the result of a single-dose bromocriptine test, treatment with a high daily dose of bromocriptine, 35 mg or more, may be necessary to obtain a favorable clinical response and normal cortisol secretion.

Adrenocorticotropic Hormone↗
PubMed1992

Resolution of possible paradoxical responses of gonadotropins to thyrotropin-releasing hormone with bromocriptine therapy in a patient with follicle-stimulating hormone-secreting pituitary adenoma.

We report the effectiveness of bromocriptine therapy in resolving the abnormal responses of plasma FSH and LH to TRH in a 70-year-old male with FSH-secreting pituitary macroadenoma who had unsuccessful transsphenoidal pituitary surgery. In the pre-treatment and post-operative periods, respectively, basal plasma levels of FSH were increased to 88.7 and 65.6 mIU/ml (normal range; 8.5-32.4) but those of plasma LH were normal being 7.0 and 4.1 mIU/ml; (normal range; 4.1 to 14.0). The responses of plasma FSH and LH to LHRH were exaggerated and their paradoxical responses to TRH were highly suggested. During the bromocriptine therapy, the basal level of plasma FSH was normalized and that of plasma LH remained normal. The magnitude of FSH and LH responses to LHRH decreased and their paradoxical responses to TRH were completely resolved.

Adenoma↗
PubMed1992

Secretory regulation of 19-hydroxyandrostenedione in normal man.

To evaluate the secretory regulation of 19-hydroxyandrostenedione (19-OH-AD), its plasma concentration was measured before and after stimulation and inhibition tests for the ACTH-adrenal axis and the renin-angiotensin system in 50 normal subjects. Basal levels of plasma 19-OH-AD did not correlate with either those of plasma renin activity (PRA) or the plasma aldosterone concentration (PAC), but positively correlated with those of plasma cortisol. Plasma 19-OH-AD was stimulated by 0.25 mg ACTH-(1-24) and was suppressed by 1 mg dexamethasone (DEX) as were plasma cortisol and PAC. On the other hand, with 2-h standing alone or iv 40 mg furosemide plus 2-h standing, plasma 19-OH-AD and cortisol did not increase but PRA and PAC did. With iv furosemide plus 2-h standing with 3 mg DEX pretreatment, plasma 19-OH-AD and cortisol did not respond either, but PRA and PAC increased. With 25 mg oral captopril following 1-h standing with 3 mg DEX pretreatment, plasma 19-OH-AD and cortisol did not change but PAC decreased. These results indicate that the secretion of 19-OH-AD is mainly under the control of the ACTH-adrenal axis rather than the renin-angiotensin system.

Adolescent↗
PubMed1992

[The relation of physical and mental stress to magnesium deficiency in patients with variant angina].

In this study we assessed the role of psychological factor in the etiology of coronary vasospasm using the Cornell Medical Index (CMI), focusing attention on the relationship between stress and serum magnesium (Mg). The study subjects consisted of 25 patients with variant angina (VA), 32 with old myocardial infarction without vasospasm (OMI), and 34 healthy men (controls). On a neurosis-discriminative diagram of CMI, areas I and II were considered as normal and areas III and IV were considered to be a neurotic disorder. The stress test included exercise and a quiz. Exercise test was performed in 8 patients with VA, 6 with OMI, and 5 controls, and a quiz was given to 4 patients with VA. Plasma catecholamines [noradrenaline (NA), adrenaline (Ad), dopamine], aldosterone, adrenocorticotropic hormone (ACTH) and serum electrolytes (Mg, Ca, Na, K, Cl) were measured before and after exposures to stress. The following results were obtained: 1) Of the patients with VA, 40.0% were categorized as area III or IV, compared to 18.7% of the patients with OMI, and 2.9% of the control subjects. 2) Among patients with VA, 64.0% exhibited anxiety states compatible with a psychological disorder. 3) NA and Ad were increased after exercise stress. 4) Serum Mg and Ca were also increased after exposure to exercise stress in all groups, and the degrees of these changes were correlated to the exercise intensity. The %delta Mg/%delta NA ratio, a parameter of the effect of catecholamine on the serum Mg, was greater in patients with VA than in those with OMI and the controls.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1992

[Development of computer software in ramp slope controller for treadmill ergometer].

We developed computer software to produce a treadmill ramp protocol through which oxygen uptake (VO2) is increased in a linear fashion, thus enabling subjects to walk until the end of exercise. The developed software simulates the increases in speed and grade of the treadmill displayed on a personal computer screen, and produces the ramp protocol by arbitrarily determining the variables of the following formula: 1) Increments of VO2 = a1t+a2 (ml/min/kg) [t = exercise time (min)] 2) Predicted VO2 by speed (S) and grade (G) = a3S2 + a4G2 + a5SG + a6S + a7G + a8 (ml/min/kg) [S = speed (km/hr); G = grade (%)] 3) Speed suitable for desired exercise time (S or S2) = a9t2 + a10t + a11 (km/hr) 4) Grade suitable for desired exercise time (G or G2) = a12t2 + a13t + a14 (%) In this study, the increment of VO2 was determined by considering the subject's exercise capacity (VO2 = 4t + 7 ml/min/kg), using the Ito's formula (VO2 = 0.067S2 + 0.289SG + 7.73 ml/min/kg). The formula of grade was determined following the formula arbitrarily (G2 = 25t + 5%). The formula of speed for exercise time was calculated automatically. The new ramp protocol, which was applied to 10 healthy subjects (mean age: 24.8 +/- 4.8 years old), disclosed a similar linear relationship between the predicted VO2 and the measured VO2.

Adult↗
PubMed1992

[Hemodynamic effects of alcohol ingestion on anaerobic threshold].

Hemodynamic influence of alcohol ingestion was evaluated using expiratory gas analysis in 10 healthy men whose mean age was 26.1 +/- 2.2 years. Protocol of the control study (C) was as follows: Oxygen uptake (VO2) at rest and during warm-up, anaerobic threshold (AT) and peak VO2 were measured with ramp protocol using a bicycle ergometer. AT was determined by the V-slope method. Protocol of the alcohol study (A) was as follows: On a different day, the same parameters as C were measured after the ingestion of 0.7 g ethanol per kg body weight. The following results were obtained: 1) The serum ethanol concentration was 79.1 +/- 13.5 mg/dl. 2) VO2 in the resting state was higher in A than in C (4.51 +/- 0.74 vs 3.61 +/- 0.62 ml/min/kg), (p < 0.05). 3) AT and peak VO2 in C and A were 17.15 +/- 2.76, 32.09 +/- 6.77 ml/min/kg and 15.43 +/- 2.86, 29.60 +/- 5.35 ml/min/kg, respectively. 4) Exercise time to the AT in C and A was 222.90 +/- 37.32 and 172.0 +/- 33.1 sec, respectively. 5) The heart rate was higher in A than in C. It was concluded that peak VO2 and AT decreased by alcohol ingestion.

Adult↗
PubMed1992

[Determination of nicarbazin in imported chicken].

The confirmation and quantitative analysis of nicarbazin (NCZ) in imported chickens were made by high performance liquid chromatography equipped with a photodiode array detector. The results showed that 1 out of 7 chicken samples contained over 30 ng/g of NCZ. The concentrations of NCZ varied from 10 to 120 ng/g according to the parts of the NCZ positive chicken samples.

Animals↗
PubMed1992

[Influence of aging and circadian fluctuation of fibrinolytic factors to the responses of these factors during venous occlusion test in healthy subjects].

This study was aimed to clarify the influence of aging and circadian fluctuation of fibrinolytic factors to changes of tissue plasminogen (t-PA) and its inhibitor (PAI-I) during venous occlusion test. Venous occlusion was achieved by application of a sphygmomanometer cuff to the upper arm of elderly healthy subjects (n = 12) and young healthy subjects (n = 12) at 10:00 am and 4:00 pm. Plasma concentration of t-PA, free PAI-1 and total PAI-1 were measured by ELISA. The activity of t-PA was measured by bioimmunoassay using monoclonal antibody for t-PA. Circadian variation was observed in the change of t-PA activity and total PAI-1. These were highly increased in the evening. However, this phenomenon was different between age groups and increase of t-PA activity occurred in elderly subjects, whereas PAI-1 was observed in young subjects. In conclusion, circadian variation and the influence of age should be considered to evaluate results of venous occlusion test.

Adult↗
PubMed1991

Magnesium content of erythrocytes in patients with vasospastic angina.

The possibility that a magnesium deficiency might be the underlying cause of vasospastic angina (VA) and the efficacy of Mg administration in its treatment were studied. Subjects included 15 patients with VA and 18 healthy subjects as the control group. The erythrocyte Mg content was measured by atomic absorption, and serum Mg was measured by conventional chemical assay. The efficacy of Mg administration was studied in seven patients with VA. The results were as follows: a) The mean erythrocyte Mg content was less in the group with frequent episodes of angina (1.59 +/- 0.11 mg/dl) than in the group without angina (2.11 +/- 0.38 mg/dl, p less than 0.01) and in the control group (2.22 +/- 0.29 mg/dl, p less than 0.01). There was no significant difference between the control group and patients of each group with respect to serum Mg. b) Coronary arterial spasm was induced by ergonovine maleate in seven patients and was completely inhibited by the administration of Mg sulfate (40-80 mEq, hourly) in six of these patients; in the remaining patient neither obvious ST change nor chest pain occurred. Thus, it was concluded that the measurement of erythrocyte Mg content is useful to determine how easily vasospasm might occur in VA and that the administration of Mg might be developed as a new therapy for spasm associated with a low erythrocyte Mg content.

Aged↗
PubMed1991

Studies on the constituents of Aconitum species. IX. The pharmacological properties of pyro-type aconitine alkaloids, components of processed aconite powder 'kako-bushi-matsu': analgesic, antiinflammatory and acute toxic activities.

Eight pyro-type aconitine alkaloids contained in the processed aconite powder 'Kako-bushi-matsu' were studied for their analgesic, antiinflammatory and acute toxic actions. All these compounds showed significant analgesic and antiinflammatory actions. Among the pyro-type alkaloids, 16-epi-pyrojesaconitine and pyrojesaconitine were the most potent analgesics. The analgesic activity of pyro-type aconitine alkaloids was lower than that of each of the parent alkaloids, aconitine, mesaconitine, hypaconitine and jesaconitine. However, pyro-type aconitine alkaloids had very low toxicity, and the decreasing rates of the toxicity in changing from the parent alkaloids to the pyro-type aconitine alkaloids were much larger than those relating to the analgesic activity. Eight pyro-type aconitine alkaloids were found to inhibit the carrageenin-induced hind paw edema at 2 to 6 h after the carrageenin subplantar injection. Consequently, it was demonstrated that the pyro-type aconitine alkaloids produced through the processing of raw aconite roots, 'Bushi', have a role in the medicinal effects of the processed aconite powder 'Kako-bushi-matsu'.

Aconitine↗
PubMed1991

Studies on the constituents of Aconitum species. XII. Syntheses of jesaconitine derivatives and their analgesic and toxic activities.

The role of the substituents at C3 and C8 of jesaconitine (1) on jesaconitine-induced analgesia and toxicity was examined. 3-O-Acetyljesaconitine (2), 3-O-anisoyljesaconitine (3), and 3-deoxyjesaconitine (6) showed dose-dependent analgesic action, and the potency of their compound-induced analgesia and toxicity was lower than those of 1. The most remarkable difference was found in the toxicity. The results indicate that the C3 hydroxy function of 1 participate in the induction of toxicity rather than of analgesia. 8-O-Linoleoyl-14-anisoylaconine (5), 8-O-methyl-14-anisoylaconine (7), 8-O-ethyl-14-anisoylaconine (8), 14-anisoylaconine (4) and 8-deoxy-14-anisoylaconine (9) showed lower activities than jesaconitine-induced analgesia and toxicity. The analgesic activity of 7 was almost the same as that of 8, but the toxicity of 7 was lower than that of 8. The analgesic activity of 9 was lower than that of 4, but the toxicities of both derivatives were not apparent. These facts indicate that the C8 function of 1 is important to the induction of analgesia and toxicity, and also that this function participates differently in the induction of the analgesia and toxicity. Subsequently, it was suggested that substituents at C3 and C8 of 1 played important roles of the induction of the analgesia and toxicity, and that the modes of this participation were not the same in analgesia and toxicity.

Aconitine↗
PubMed1991

A case of epicardial cyst.

A rare case of epicardial cyst diagnosed at surgery was presented. A 64-year old woman was admitted for evaluation of a mediastinal mass shown by echocardiography to be adjacent to both ventricles. Computed tomography (CT) and magnetic resonance imaging (MRI) studies were performed. On CT, there was evidence of an abnormal mass lesion at the lateral side of the outlet of the right ventricle. The CT number of the mass was 24.7, suggesting cystic lesion. MRI revealed that the intensity of the lesion signal was higher than that of subcutaneous fat on the T2 weighted image. On the T1 weighted image, a low intensity was identified in the same region. During operation a mass originating from the epicardium was diagnosed as an epicardial cyst.

Echocardiography↗