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Biomedical subjects

M Miyazaki

Publications and source records attributed to M Miyazaki.

At least 919 records · Page 51Linked to original sources
PubMed1983

The correlation between tremor characteristics and the predicted volume of effective lesions in stereotaxic nucleus ventralis intermedius thalamotomy.

In 51 cases (6 cases with bilateral operations) with various kinds of tremor, stereotaxic ventralis intermedius (Vim) thalamotomies were performed using Leksell's apparatus and the results of operation evaluated. Several characteristics of the tremor, including clinical features and EMG, were correlated with the assumed location and volume of the coagulative lesion. In 54 of the 57 operations, the thalamic Vim nucleus was identified physiologically and a therapeutic lesion placed at a site that included the Vim neurons. In all these cases, except one in which the lesion was estimated to be too small, tremor was immediately abolished by a relatively small lesion. The estimated volume of the lesion was about 40 to 200 mm3 and the effect persisted over a long follow-up period (maximum ten years). The size of the lesion that was necessary apparently depended on several features of the tremor. A larger lesion was required in cases of movement type tremor, tremor with a low rate (less than 4 Hz), tremor of high amplitude (more than 600 microV), and tremor involving proximal muscles or with a wide distribution. Tremor following a cerebrovascular lesion and post-traumatic tremor were characterized by coarse oscillation (high amplitude and low frequency) involving proximal muscles. A relatively larger coagulative lesion was therefore necessary to relieve this type of tremor. In contrast, parkinsonian and essential tremor were usually of low amplitude and distal in distribution. For the relief of such tremor, the lesion could be very small: if aided by electrophysiological methods to identify Vim neurons, the minimal effective volume of the lesion was estimated as about 40 mm3 and restricted to the Vim nucleus. Based on these results, the importance of the Vim nucleus in tremor mechanisms is discussed.

Adult↗
PubMed1983

Stereotactic selective thalamotomy for the treatment of tremor type cerebral palsy in adolescence.

6 cases with tremor-athetotic type cerebral palsy and 2 cases with moderate dystonia-tremor type cerebral palsy were treated by selective stereotactic thalamotomy. In the former group, postural-movement type tremor in the upper limb gradually progressed with age while athetosis remained unchanged. In the latter group, dystonia in the truncal muscles predominated over the irregular tremulous movement of the upper limbs. In all cases, the intelligence was almost normal. Stereotactic selective thalamotomy (Vim for tremor athetosis, VL-Vim for dystonia tremor) was performed under local anesthesia with the aid of radiological and neurophysiological control methods. The results of the operations were satisfactory in regard to the tremor relief and concomitant improvement of motor performances in most of the cases. Stereotactic treatment might be an effective way to make possible a one-step progress in these handicapped cases. The importance of postoperative physical therapy is also emphasized.

Adolescent↗
PubMed1983

Chronological changes of electrocochleogram in experimental endolymphatic hydrops. Special reference with AP output potential and hair cell cilia.

Chronological changes of the whole nerve action potential (AP), cochlear microphonics (CM) and summating potential (SP) in experimental endolymphatic hydrops in guinea pigs were studied during a period from 1 week to 13 months after the endolymphatic sac obliteration. Endolymphatic hydrops became extensive in month 3 and persisted thereafter. The threshold of AP increased with the lapse of time but good AP output potential was obtained, being maximum in month 3. The threshold of CM increased with the lapse of time. The CM output potential was the highest around week 3 when endolymphatic hydrops was slightly formed, and it decreased thereafter. SP responses at the frequencies of 8, 4, 1 and 0.5 kHz showed the reversed polarity of -SP in month 3 and changed towards potential 0 thereafter. In animals showing super-normal AP output potential, the cilia in the third row of outer hair cells were disarranged. This seems to be involved in recruitment.

Action Potentials↗
PubMed1983

Neuromuscular junctions of the posterior cricoarytenoid muscle in the cat.

The motor end plate of the cat posterior cricoarytenoid muscle is examined by using electron microscope and histochemical method. Furthermore, we studied the localization of acetylcholine receptors by fluorescent staining of snake neurotoxins (alpha-bungarotoxin and erabutoxin b) and autoradiography of 125I-labeled alpha-bungarotoxin. The fine structure of the motor end plate of this muscle is approximately identical to that of other singly innervated skeletal muscles. The subneural apparatus is activated by cholinesterase (ChE). ChE reaction appears markedly in primary and secondary synaptic clefts. No remarkable difference is found between TMR-labeled neurotoxin and FITC-conjugated neurotoxin. Fluorescent staining is associated with subsynaptic muscle membranes and not with motor nerve terminals. The autoradiogram revealed heavy accumulations of grains at the junctional folds.

Animals↗
PubMed1983

[Liver cell carcinoma with extensive proliferation of sarcoma-like neoplastic cells--an autopsy case].

A 73-year-old male was admitted with suspected Grawitz tumor. Aspiration cytology from the tumor was diagnosed as Class V with suspected sarcoma. He died 17 days after admission. Autopsy revealed this to be a massive hepatic tumor occupying over half of the right lobe. It showed protrusion into the right retroperitoneum. Histology of the tumor evidenced widespread proliferation of sarcoma-like neoplastic cells besides a minute area of definite liver cell carcinoma in the center of the tumor mass. Definite transitional features between liver cell carcinoma and a sarcomatous pattern, the latter involving a major part of this tumor, were noted. Thus, we diagnosed this tumor to be liver cell carcinoma with a sarcoma-like histological pattern. The possibility of collision tumor or carcinosarcoma could be ruled out.

Aged↗
PubMed1983

Comparison of in-vivo thermochemotherapy of isolated rat liver through portal vein and hepatic artery.

A model for the in-vivo perfusion of the isolated rat liver with either cytotoxic agents or hyperthermic saline, administered through either the hepatic artery or the portal vein, is described. Rats were able to survive following perfusion with a dose of up to 0.25 g/kg of 5-fluorouracil and 2.0 to 2.5 mg/kg of mitomycin-C by both routes. Regional hyperthermic perfusion of the liver produced temperature and time-dependent hepatotoxic effects. A marked elevation of serum glutamic oxaloacetic and glutamic pyruvic transaminase levels was noted 24 hours after perfusion, but was reversible. Aminopyrine N-demethylase activity in both normal intact and regenerating rat liver was not affected; however, the activity in normal intact liver was markedly suppressed with hyperthermic perfusion at 43 degrees C only. Incorporation of tritiated thymidine into hepatic deoxyribonucleic acid 24 hours after partial hepatectomy was severely inhibited by prior hepatic perfusion with either cytotoxic drugs or hyperthermic saline. This in-vivo isolated perfusion technique could be used to assess the effect of thermochemotherapy on tumour growth in the liver.

Aminopyrine N-Demethylase↗
PubMed1983

Reversal of lethal, chemotherapeutically induced acute hepatic necrosis in rats by regenerating liver cytosol.

In this report we further evaluate the role of regenerating liver cytosol (RLC) as a stimulator of hepatic regeneration by assessing its effect on survival, liver function, and hepatic regeneration in a model of in vivo isolated perfusion of the rat liver with high concentrations of cytotoxic drugs and regional hyperthermia. Isolated perfusion with 500 mg/kg of 5-fluorouracil (5-FU) and 2.5 mg/kg of mitomycin-C (Mit-C) resulted in 70% (n = 20) and 71% (n = 14) mortality, respectively, from 2 to 7 days after perfusion, with extensive, patchy necrosis and infarction seen on histologic examination and markedly elevated levels of serum glutamic oxaloacetic transaminase (SGOT) and serum glutamic pyruvic transaminase (SGPT) at 6 and 24 hours after perfusion. The intraperitoneal administration of RLC (80 mg total protein/rat) at the time of hepatic perfusion resulted in 70% (5-FU, n = 20, P less than 0.05) and 80% (Mit-C, n = 20, P less than 0.01) survival at 21 days post perfusion. RLC-treated rats demonstrated significantly lower SGOT and SGPT levels at 6 and 24 hours after perfusion and normal liver histologic appearance by 14 days after perfusion in surviving rats. Hepatic regenerative capacity following partial hepatectomy was severely inhibited (P less than 0.001) following isolated hepatic perfusion with sublethal doses of 5-FU (125 mg/kg, 250 mg/kg), Mit-C (1.5 mg/kg) and hyperthermia (41 degrees C and 43 degrees C X 5 minutes). The administration of RLC at the time of partial hepatectomy restored the DNA synthetic response in perfused rats to that seen in normal control rats after partial hepatectomy (P less than 0.05). These results demonstrate that the liver is the source of a factor (s) (RLC) that significantly improves survival after lethal chemotherapeutic injury to the liver by stimulating endogenous hepatic regeneration. A potential clinical application for a stimulator of hepatic regeneration in situations of deliberate, therapeutic insult to the liver is suggested.

Acute Disease↗
PubMed1983

[Combined antitumor therapy with polyamine biosynthesis inhibitors and mitomycin C].

A combined effect of the polyamine biosynthesis inhibitors, alpha-difluoromethylornithine (DFMO) and methyglyoxal-bis-guanylhydrazone (MGBG) with mitomycin C (MMC) was studied. DFMO, MGBG and MMC were given intraperitoneally to nude mice xenotransplanted human gastric cancer. This new combination of the three drugs resulted in the complete halt of the xenotransplanted tumor growth and marked decline of spermine levels in the tumor tissues. The other treatments with DFMO and MGBG as well as MMC alone were inferior to this new combined therapy in suppression in both tumor growth and tissue spermine level. These data suggest that this new combined treatment be effective against human gastric cancer.

Animals↗
PubMed1983

[Autopsy case of atypical medulloblastoma in an adult].

A 24-year-old female complained of headache and vomiting. The brain-CT scan demonstrated a tumor shadow in the right cerebellar hemisphere. The tumor was partially resected, and irradiation therapy was started. She died of intraventricular hemorrhage about 6 months after the onset of symptoms. Autopsy revealed a recurrent tumor mass in the cerebellum extending to the brain stem. It showed systemic metastases to the leptomeninx, liver, bones and ovaries. Histological examination showed a tumor which was a primarily composed of typical medulloblastoma cells with occasional Homer-Wright type rosettes. It partly showed glioblastoma-like configuration. Some tumor cells were positive for GFAP by the PAP method, suggesting glial differentiation.

Adult↗