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Biomedical subjects

S Miyazaki

Publications and source records attributed to S Miyazaki.

At least 595 records · Page 33Linked to original sources
PubMed1989

Tic douloureux caused by primitive trigeminal artery or its variant.

Primitive trigeminal artery (PTA) is an extremely rare cause of tic douloureux. None of the reports on PTA variant, which is an anomalous cerebellar artery arising from the internal carotid artery without anastomosis to the basilar artery, has suggested the possibility of this vessel causing tic douloureux. Eight cases of tic douloureux are reported in which a PTA or PTA variant was found during microvascular decompression (MVD). These cases were derived from a series of 1257 patients treated with MVD for tic douloureux. In one patient, the neuralgia was caused by a combination of vessels: a PTA, the superior cerebellar artery, and the anterior inferior cerebellar artery. In the other seven cases, a PTA variant was compressing the root entry zone of the trigeminal nerve. All eight patients gained excellent pain relief after MVD of the root entry zone. The significance of PTA's and PTA variants as the cause of tic douloureux and the effectiveness of MVD in the management of such cases are discussed.

Aged↗
PubMed1989

Parapontine trigeminal cryptic angiomas presenting as trigeminal neuralgia.

Posterior fossa microvascular decompression surgery was attempted in 1257 patients with trigeminal neuralgia (TN), of whom seven had a very unusual cryptic angioma. The lesions were not visualized on preoperative enhanced computerized tomography scans, and serial angiography demonstrated a small vascular stain in only one case. The character of the facial pain was indistinguishable from TN caused by vascular compression and there was no other specific symptomatology. The patients' age and sex distributions were also compatible with classical TN. Cryptic angiomas presenting as typical TN without other symptoms have not been reported before, but they should be kept in mind in the differential diagnosis and surgical management of TN.

Cerebral Angiography↗
PubMed1989

An electronic device for hearing-handicapped drivers: evaluation of performance.

There are several countries in the world in which people with severe hearing loss are not eligible for a car driver's license. As a technical approach to solve this problem, an electronic device is developed which detects traffic-alarm-sounds, i.e. horns of cars, sirens of emergency vehicles and alarm signals of railroad crossings, and then displays them as vibration to the driver. The basic operating principle of the device is that those traffic-alarm-sounds have marked regularity in some particular frequency region whereas the traffic noise is a wide-band random noise. The real time detection of the regularity is realized by use of a phase-locked-loop and a simplified lock-in amplifier. The results of simulation experiments and road tests demonstrate that the performance of the device is satisfactory except in the case of the detection of the alarm signals of railroad crossings.

Automobile Driving↗
PubMed1989

[A case of chronic myelogenous leukemia complicated with nephrotic syndrome].

An 81-year-old woman was admitted, complained general malaise, and edema on face and lower extremities. In the peripheral blood, leucocytosis (17,220/mm3), microcytic hypochromic anemia (RBC 348 x 10(4)/mm3, Hb 9.6 g/dl, Ht 29.2%), and thrombocytosis (130 x 10(4)/mm3) were present, and many myeloid cells containing of myeloblasts, promyelocytes and so on were observed. Bone marrow aspiration revealed increment of the myeloid series without hiatus leukemia . The Neutrophil Alkaline Phosphatase score and rate was low, and on bone marrow scintigram using indium chloride, liver and extremities were shown. On admission, proteinuria (21.5 g/dl) and hypoalbuminemia (2.5 g/day) were pointed out, and the renal biopsy specimen showed membraneous proliferative glomerulonephritis (MPGN), so we diagnosed this case that chronic myelogenous leukemia (CML) complicated with nephrotic syndrome. At first, she was treated with prednisolone, but proteinuria was not entirely improved, then busulfan was given, myeloid cells in peripheral blood were disappeared and proteinuria was gradually decreased. From this coarse, the causality between CML and nephrotic syndrome was verified.

Aged↗
PubMed1989

Glanzmann's thrombasthenia associated with a transient deficiency of factor XIII.

A three-year-old girl suffering from ecchymoses developed severe epistaxis. The diagnosis of thrombasthenia was made on the basis of platelet aggregation studies, flow cytometric analysis with monoclonal antibodies and gel electrophoretic analysis. In addition, coagulation studies at the time of epistaxis repeatedly showed a transient deficiency of factor XIII activity and antigen.

Blood Platelet Disorders↗
PubMed1989

[Characterization of 12-L-hydroxy 5, 8, 10-heptadecatrienoic acid produced by rat basophilic leukemia-2H3 cells].

14C- 12-L-hydroxy-5, 8, 10-heptadecatrienoic acid was produced by incubating the 10,000 x g supernatant of rat basophilic leukemia -2H3 cells with 14C-arachidonic acid in the presence of isoproterenol and hemoglobin. The Vmax was 125 p mol/min/2 x 10(7) cells and its Km value was 1.28 n mol, indicating the low synthetic activity even though a sufficient amount of the substrate was available. The synthesis was dose-dependently decreased by the addition of calcium ions and inhibited by ETYA and indomethacin but not by imidazol, suggesting that the production might be non-enzymatic break-down from PGH2.

Animals↗
PubMed1989

[A case of renal capillary hemangioma].

This is a case of a 18 year-old female with capillary hemangioma of the left kidney. This tumor forms a well-demarcated solid mass showing a low grade contrast enhancement on CT, an echogenic pattern on sonogram, and hypovascularity on angiography. The radiologic findings on this tumor have wide variations in the previously reported cases.

Adolescent↗
PubMed1989

[Clinical study of aminoglycosides on renal dysfunction--pharmacokinetics of arbekacin and its elimination effects by hemodialysis and adsorption with charcoal].

In vitro studies of elimination of arbekacin (HBK), a new aminoglycoside antibiotic, from blood by means of hemodialysis or adsorption with charcoal, and pharmacokinetic studies in patients with renal dysfunction were examined. HBK was well eliminated by hollow fiber type artificial kidney (HFAK) with a half-life of 0.13 hr. HBK was also well eliminated by an adsorption tube containing charcoal with even shorter half-life of 0.03 hr. As to pharmacokinetics of HBK in patients with renal dysfunction, blood levels became higher with a greater reduction in 24 hr endogenous creatinine clearance (Ccr). A decreasing tendency was also seen in urinary recovery rate. These results indicated that hemodialysis and adsorption with charcoal are useful for elimination of HBK from blood. It is recommendable in patients with renal dysfunction to take some measures such as prolongation of administration interval of HBK according to the extent of decrease in Ccr.

Adsorption↗
PubMed1989

[Measurement of coefficient of variation of R-R interval in ECG for patients with impotence].

The coefficient of variation (CV = SD/mean x 100) of the R-R interval in electrocardiogram (ECG) was measured as an indication of parasympathetic nerve function in patients with impotence. Of 762 patients 104 (13.6%) had a CV value lower than 2.0. The factors which led to the low CV value were evident in 50 patients (48%), i.e. diabetes mellitus in 26, side effects by antiulcer, antidepressant or antihypertensive agent in 16, renal failure in 1, alcoholism in 2 and age over 70 years old in 4. The possible factors of the low CV value, such as neurogenic, thyroid, cardiovascular and endocrine disorders were found in 12 patients (11.5%). In the remaining 42 patients (40.4%), CV value was decreased by unknown factors. Measurement of CV of R-R interval in ECG was safe and useful as a screening test for patients with impotence to detect the dysfunction of the parasympathetic nerve system.

Adult↗
PubMed1989

[Measurement of penile brachial index (PBI) in patients with impotence].

PBI was measured in 555 patients chosen at random from those who visited our impotence clinic between October 1984 and September 1986. Of 555 patients with impotence 29 (5.2%) showed a low PBI level of less than 0.6. On the basis of carefully taken history, risk factors causing the disturbance of penile blood flow were found in 13 (44.8%) of these 29 patients. They included diabetes mellitus, hypertension, surgery of pelvic organ, vertebral injury, vascular disorder of brain and gangliosympathectomy. Although penile angiography is necessary to make the definite diagnosis of vasculogenic impotence, hospitalization is usually required to perform the examination. Measurement of PBI is useful as a screening test to detect vasculogenic impotence at an outpatient clinic, because this examination is noninvasive and technically easy.

Adolescent↗
PubMed1988

Acute hemodynamic effects of MDL19205 on conscious dogs with mitral regurgitation.

To assess the effects of MDL19205, a combined inotropic-vasodilating agent, or an inodilator, on the left ventricle with subacute volume overload due to mitral regurgitation (MR), seven dogs were instrumented with a left ventricular (LV) micromanometer and a pair of ultrasonic crystals for the measurement of LV circumferential segment length. After examining the effects of this drug in the normal hearts, its effects were observed in the same dogs in which MR was produced by sectioning chordae tendineae. Mitral regurgitation caused increases in LV peak dP/dt (2,384 +/- 256 to 3,090 +/- 622 mmHg/sec; p less than 0.05), mean circumferential shortening velocity (Vcf; 1.41 +/- 0.25 to 1.85 +/- 0.20 sec-1; p less than 0.05), LV end-diastolic pressure (LVEDP; 8.2 +/- 1.6 to 15.8 +/- 3.7 mmHg; p less than 0.001), and LV end-diastolic length (LVEDL; 10 to 10.6 +/- 0.2mm; p less than 0.01). The dogs were intravenously administered MDL19205 7 to 14 days after they had completely recovered from the first and second operations. With 3 mg/kg of MDL19205, peak changes of hemodynamic indices occurred within 5 minutes in the hearts with MR LV dP/dt and mean Vcf significantly rose (from 3,090 +/- 622 to 5,356 +/- 811 mmHg/sec; p less than 0.001, 1.85 +/- 0.20 to 2.65 +/- 0.36 sec-1, p less than 0.001). LVEDP and LVEDL were returned to the control values obtained in the normal hearts (15.8 +/- 3.7 to 6.4 +/- 2.4 mmHg; p less than 0.001, 10.6 +/- 0.2 to 10 +/- 0.4; p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Recurrent left ventricular mural thrombi in a patient with acute myocarditis.

A case of acute myocarditis with recurrent left ventricular mural thrombi in a 59-year-old man is reported. Two-dimensional echocardiogram demonstrated left ventricular mural thrombus with apical dyskinesis on the 2nd day after the onset of chest oppression. No hemoagglutination abnormalities were present. Anticoagulation treatment with heparin was initiated. A two-dimensional echocardiogram obtained on the 15th day showed that the left ventricular wall motion had become normal and that the thrombus had disappeared. However, on the 38th day, a new pedunculated free mobile thrombus was found in the apical part of the left ventricle despite the normal wall motion. By the 46th day, the new thrombus had disappeared. The present case suggests that mural thrombi can occur in the absence of left ventricular dyskinesis and dilatation. Anticoagulation therapy resolved the mural thrombi but could not prevent the recurrence at the apex. Thus, in acute myocarditis, a mural thrombus may appear as a result of the endocardial damage, even when blood stasis is absent.

Acute Disease↗
PubMed1988

Influence of visual deprivation on the visual and oculomotor system: acetylcholinesterase activity in oculomotor neurons.

The effects of visual deprivation (dark-rearing) on neurons in both the visual and oculomotor systems of black mice were studied using morphologic and histochemical techniques. In the neurons of the dorsal nucleus of the lateral geniculate body, the cytoplasm of dark-reared mice was less developed and the cytoplasm/nucleus ratio was significantly smaller in the dark-reared mice than in the controls. In contrast, large motoneurons in the oculomotor nucleus did not show any ultrastructural changes and the cytoplasm/nucleus ratio was normal. However, in large motoneurons of dark-reared mice, acetylcholinesterase (AChE)-positive areas were scattered in the cytoplasm, and the ratio of the AChE-positive areas to the cytoplasm area was significantly smaller than that in the controls.

Acetylcholinesterase↗
PubMed1988

Supranormal levels of serotonin and its metabolite after raphe cell transplantation in serotonin-denervated rat hippocampus.

Transplantation of fetal raphe cells (14 days of gestation) into the adult rat hippocampus, 2 weeks following serotonin (5-HT)-denervation with intracisternal injection of 5,7-dihydroxytryptamine, can restore 5-HT and 5-hydroxyindoleacetic acid (5-HIAA) levels in the hippocampus to far beyond normal values. Transplantation into the unilateral hippocampus produces asymmetrical turning behavior after administration of the 5-HT releasor, p-chloroamphetamine (IP), comparable to the behavior reported for rats with 5-HT denervation of the unilateral hippocampus. The effect is blocked by prior depletion of 5-HT with p-chlorophenylalanine (IP). The asymmetry in 5-HT levels are correlated with the behavioral change. These data indicate that a large amount of 5-HT is released from nerve terminals of transplanted raphe cells, and suggest that the supranormal levels of 5-HT and 5-HIAA after raphe cell transplantation are neurochemical correlates of 5-HT hyper-innervation of the hippocampus which has been reported previously.

5,7-Dihydroxytryptamine↗
PubMed1988

Inositol 1,4,5-trisphosphate-induced calcium release and guanine nucleotide-binding protein-mediated periodic calcium rises in golden hamster eggs.

Periodic increases in intracellular free calcium occur upon fertilization of golden hamster eggs (Miyazaki et al. 1986. Dev. Biol. 118:259-267). To investigate the underlying mechanism, inositol 1,4,5-trisphosphate (IP3) and guanine nucleotides were microinjected into the egg while Ca2+ transients were monitored by aequorin luminescence and/or hyperpolarization in the membrane potential, which indicates the exact timing and spatial distribution of the Ca2+ rise. Injection of IP3 induced an immediate Ca2+ transient of 13-18 s in the entire egg. The critical concentration of IP3 was 80 nM in the injection pipette (2 nM in the egg, assuming uniform distribution); the effect was all-or-none. The Ca2+ rise occurred even in Ca-free external medium. Injection of 5 mM GTP or 0.33 mM guanosine-5'-O-(3-thiotriphosphate) (GTP gamma S) (calculated intracellular concentration, 200 or 12 microM, respectively) caused a similar Ca2+ transient with a delay of 160-200 s. More than 50 microM GTP gamma S produced recurring and attenuating Ca2+ transients in a local area of the cytoplasm, with an initial delay of 25-40 s and intervals of 45-60 s. In Ca-free medium the first one to two Ca2+ transients occurred but succeeding ones were absent. Preinjection of guanosine-5'-O-(2-thiodiphosphate) inhibited the occurrence of both GTP gamma S-induced and sperm-induced Ca2+ transients in a dose-dependent manner. Neither pertussis nor cholera toxins had effect. It was proposed that sperm-egg interaction activates a GTP-binding protein that stimulates production of IP3, causing the first one to two Ca releases from internal stores, and also stimulates a pathway for elevation of Ca2+ permeability in the plasma membrane, thereby sustaining the repeated Ca2+ releases.

Aequorin↗