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Biomedical subjects

K Morimoto

Publications and source records attributed to K Morimoto.

At least 577 records · Page 32Linked to original sources
PubMed1986

Deep prepyriform cortex kindling and its relation to amygdala kindling in the rat.

Kindling of the deep prepyriform cortex (DPC), a recently identified sensitive site to chemoconvulsants, was compared to kindling of the amygdala in rats. Although the two kindled sites were very similar in their initial responses, electroencephalographic changes during kindling stimulation, kindling seizure development, and growth of afterdischarge, they differed in that the deep prepyriform cortex showed a significantly lower final threshold, a significantly higher frequency of afterdischarge and a significantly shorter latency to bilateral forelimb clonus than the amygdala. Significant bidirectional transfer was found during secondary kindling of either of the two sites, suggesting a close interrelation between them. Rhythmic synchronous discharge was directly induced in the deep prepyriform cortex by ipsilateral amygdala stimulation, but not in the amygdala by ipsilateral cortical stimulation. Local application of both muscimol (0.45 nM) and 2-amino-5-phosphonovaleric acid (25 nM) into the cortical site reduced the afterdischarge duration of amygdala-kindled seizures by approximately 20% without changing the type or duration of the motor seizure. We suggest that the deep prepyriform cortex is "downstream" from the amygdala in the preferential routes of afterdischarge propagation, and that, although the deep prepyriform cortical neurocircuits of GABA and excitatory amino acids may be involved in the maintenance of amygdala-kindled, self-sustained afterdischarge, they are not essential in the expression of amygdala-kindled motor convulsions.

2-Amino-5-phosphonovalerate↗
PubMed1986

Cell-stage dependence of mutagen-induced sister-chromatid exchanges in human lymphocyte cultures.

The induction of sister-chromatid exchanges (SCEs) was studied in phytohemagglutinin (PHA)-stimulated human lymphocytes exposed for 1 h to mitomycin C (MMC, 3 X 10(-6) M), ethyl methanesulphonate (EMS, 2 X 10(-2) M), or 4-nitroquinoline-1-oxide (4NQO, 3 X 10(-5) M) at various cell-cycle stages of 72-h cultures. The doses of the chemical were chosen to give about 20 SCEs per cell when treated at Go. The SCE frequency increased almost linearly with MMC or EMS treatments at later times after PHA stimulation, peaking with those at 36 h (at around the first G1/S boundary in the 2 consecutive cell cycles, which was revealed by concomitant experiments), and then decreased with subsequent treatment times. Cell-cycle kinetics and the cell stages at which the cells were treated were measured by autoradiography and sister-chromatid differential staining. The data show that MMC and EMS produce larger numbers of SCEs when treated at stages closer to the beginning of S, and that the most efficient time of treatment is the G1/S boundary in the first cell cycle of the two consecutive cycles before sampling. Pulse treatment with EMS caused about 3 times larger inductions of SCEs when done at late G1/early S(G1/S boundary) in the first cell cycle compared to that at G0/early G1, whereas identical exposure to MMC at the first G1/S boundary produced only 1.5 times larger numbers of SCEs than that at G0/early G1. EMS and MMC both, however, induced 30-40% larger numbers of SCEs when treated at the G1/S boundary in the first cell cycle than when treated at the second cell cycle before sampling. On the contrary, treatment with 4NQO led to the induction of about the same numbers of SCEs even when treated at different cell-cycle stages before the second G1/S boundary. The SCE frequency in 4NQO-treated cells then decreased with subsequent treatment times.

4-Nitroquinoline-1-oxide↗
PubMed1986

Effects of temperature on chemically induced sister-chromatid exchange in human lymphocytes.

Lymphocytes from healthy adults were studied for sister-chromatid exchanges (SCEs) when pulse-treated in G0 with mitomycin C (MMC), ethyl methanesulfonate (EMS), or 4-nitroquinoline N-oxide (4NQO) at various temperatures ranging from 0 degrees C to 41 degrees C and then cultured in medium containing 5-bromodeoxyuridine at 37 degrees C. The results showed that the frequencies of SCEs induced by MMC or EMS varied according to the treatment temperature. In MMC- or EMS-exposed cultures, the SCE frequency increased continuously with increasing treatment temperature; treatment at 37 degrees C resulted in a 3-4 times greater induction of SCEs than did that at room temperature (25 degrees C). On the other hand, SCE frequencies in cells exposed to 4NQO remained within normal deviation, showing no temperature-dependent changes. Baseline SCE frequencies remained almost constant within the temperature range tested. These data indicate that treatment temperature is a very critical factor in determining the sensitivity of cells to the chemical induction of SCEs.

4-Nitroquinoline-1-oxide↗
PubMed1986

Oral zinc therapy normalizes serum uric acid level in Wilson's disease patients.

The authors investigated changes in the serum uric acid (s-UrA) level seen in a Wilson's disease patient who had to undergo oral zinc therapy because of the occurrence of D-penicillamine-induced acute sensitivity reactions, including neutrophilic agranulocytosis, thrombocytopenia, and skin eruptions. Although s-UrA levels were low before oral zinc therapy (mean +/- SD, 1.60 +/- 0.20), they increased (mean +/- SD, 2.63 +/- 0.32) to within normal range (2.8-8.0 mg/dl) after therapy. There were no significant changes in the renal tubular reabsorption of UrA during oral zinc therapy. This therapy also produced an improvement of the decreased cholinesterase (ChE) values usually seen in Wilson's disease. These results suggest that oral zinc therapy can normalize UrA metabolism in Wilson's disease by improving liver dysfunction and increasing UrA synthesis.

Administration, Oral↗
PubMed1986

Genotoxicity of diesel exhaust emissions in a battery of in-vitro short-term and in-vivo bioassays.

The present studies confirm that diesel exhaust emissions are mutagenic in bacterial and mammalian mutation assays. Our results further indicate that mutagenic potential of the diesel tar samples can be reduced by exogenous metabolic activation with S15, and that Epstein-Barr-virus transformed lymphoblastoid cell lines from Bloom syndrome, and Xeroderma Pigmentosum patients with a high incidence of malignant tumors showed an larger production of SCEs while those from Fanconi anemia patients had an lower frequency of SCEs when exposed to the diesel emission condensate, compared to those from normal healthy persons. On the contrary to the results of in-vitro studies, the in-vivo SCE and micronucleus assays using mouse and rat bone marrow cells gave negative responses.

Animals↗
PubMed1986

[A false aneurysm caused by rupture of a double velour Dacron graft. A case report].

A 71-year-old man was operated for a complete occlusion of the left common iliac artery caused by arteriosclerosis obliterans. Cross-over bypass was performed from the right external iliac artery to the left superficial femoral artery in June 1978, using a Double Velour Dacron graft (Cooley) 8 mm in diameter. In February 1985, the patient noticed the pulsatile mass in his left groin. Angiography showed a false aneurysm at the distal anastomosis of the graft. On operation, 2 aneurysmal dilatations were found on the distal anastomosis. After resection of the aneurysms, the reconstruction was established by EPTFE graft successfully. The resected specimen showed that one of the aneurysms was caused by the anastomotic failure of the distal portion of the graft, but that the other was the false aneurysm caused by rupture of the implanted graft. Two ruptured holes were confirmed to be 20 X 25 mm, 10 X 15 mm in size respectively, 10 mm proximal to the anastomotic aneurysm. Rupture of the Dacron arterial prosthesis is a rare complication. Only 23 cases have been reported in the United States. But some literatures show that the incidence of the failure of the Dacron prosthesis was about 3%. Therefore, we should make a long-term follow-up to the patients implanted Dacron arterial prostheses.

Aged↗
PubMed1986

Angiotensin I level and sporadic hypokalemic periodic paralysis.

A patient with secondary (sporadic type) hypokalemic periodic paralysis with relative hypertension had reninism with a high concentration of plasma angiotensin I (ANG-I) but no hyperaldosteronism or high angiotensin II value. Angiotensin-converting enzyme (ACE) activity was usually normal. Results of other hormonal analyses were also normal. However, the glomerular filtration rate and filtration fraction of the kidneys were greatly elevated. Despite severe hypokalemia, the patient's potassium clearance was high. No evidence of distinct hyperplasia of the juxtaglomerular cells was obtained. These results suggest that decreased affinity of ACE to the substrate ANG-I (so-called ACE dysfunction syndrome) produced the reninism and high concentration of plasma ANG-I, and that the latter induced an increase in the glomerular filtration rate of the kidneys with sequential occurrence of secondary hypokalemic periodic paralysis.

Adolescent↗
PubMed1986

[Lumbosacral lipoma: computed tomographic scan findings and surgical correction].

Display of the specific anatomic derangements by high-resolution computed tomographic (= CT) scan provides an important basis for planning corrective surgery of lumbosacral lipoma. In this paper, analysis of four infants and a child with lumbosacral lipoma revealed following discrepancy between the image by CT scan and operative finding. Most of lipoma showed a sharply outlined area of low density (approximately -100 H.U.) in the CT scan. Lipoma in the spinal cord parenchym represented intermingled fatty and neural tissue. There were also relatively high density areas in some cases and correspondingly, there were very fibrous lipomas, which could be identified by microscopic histological examination. Although there was a general correlation between the site of lumbosacral skin abnormality and underlying intraspinal lesion, some case does not match perfectly. In conclusion, a removal of the lumbosacral lipoma for the tethering effect always preferable to a total extirpation even though with technological advances in operative magnification and surgical instrumentation and a removal of the compressing lamina is necessary for adequate decompression.

Child↗
PubMed1986

[Cardiac myxoma metastatic to the brain].

A case of cardiac myxoma presenting as metastatic brain tumor are reported. The patient was a 44-year-old man. One year prior to this admission, he had suffered stroke, which was characterized by right hemiparesis and dysarthria. The computed tomographic (= CT) scan of the head at that time showed a low density on the left basal ganglia and the echocardiogram suggested a left atrial myxoma. At surgery, a polypoid myxoma attached to the atrial septum was totally removed. Right hemiparesis was improved and the patient was discharged. A few months later, the patient was evaluated for multiple cutaneous masses and diagnosed by biopsy as metastatic myxoma. The patient's condition remained unchanged until this admission. In March 1985, the patient had a tonic-clonic convulsion marching from right hand and developed right hemiplegia with drowsy. An echocardiogram failed to reveal recurrence of the cardiac myxoma. A CT scan revealed a 5-cm, relatively circumscribed, low density mass in the left fronto-parietal lobe, ring mottled enhancement after contrast administration and more enhancement in the delayed scanning of 45 min. Craniotomy showed a tender, friable tumor with a yellowish cyst fluid, but apparently not invading the brain parenchyma. After complete excision of the mass, there was rapid lessing in the hemiplegia and improvement in the level of consciousness. A contrast-enhancement CT scan performed 2 weeks after craniotomy revealed no evidence of residual tumor. Pathohistological examination showed spindle-shaped and stellate cells which formed clusters and contained large amounts of acid polysaccharides as demonstrated by the alcian blue method.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1985

Assignment of amides in the amino acid sequence of mammalian calmodulin by mass spectrometry.

The primary structure of mammalian calmodulin from various sources was analyzed by secondary ion mass spectrometry. The assignments of amide groups at residues 24, 60, 129 and 135, which had been controversial in the previous reports, were in perfect agreement with the amino acid sequence deduced from the cDNA sequence of calmodulin of other vertebrates. The result is against the post-translational amidation or deamidation process of this protein.

Amides↗
PubMed1985

Sugar components of glycoprotein fractions in middle ear effusions.

We analyzed the sugar components of the glycoprotein fractions in human middle ear fluid samples by using gas chromatography. All ear effusions included serous, seromucinous and mucoid samples, and contained appreciable amounts of fucose, mannose, galactose, glucose, N-acetyl glucosamine and sialic acid. Total sugar content to protein was significantly higher in mucoid effusions than in serous effusions. Among the sugar components, the contents of sialic acid, N-acetyl glucosamine, fucose and galactose were much higher in the mucoid effusions. The data show new evidence that some glycoproteins having high proportions of sialic acid, N-acetyl glucosamine, fucose and galactose appear in the middle ear fluid of the glue ear.

Amino Sugars↗
PubMed1985

Effects of thyrotropin-releasing hormone on evoked responses and long-term potentiation in dentate gyrus of rat.

Thyrotropin-releasing hormone (TRH), a neuropeptide with multiple neuromodulatory functions, has been receiving examination for clinical relevance in epilepsy. To investigate the neurophysiologic properties of the anticonvulsant action of TRH, its effects on the evoked responses and long-term potentiation (LTP) of the perforant path input to the dentate gyrus were examined in anesthetized rats. Intracerebroventricular microinjected 80 micrograms TRH increased the relationship between the amplitude of the population spike and the slope of the EPSP, and reduced the LTP of the EPSP by approximately 30% compared with saline-injected controls. The TRH, however, slightly increased the amplitude of the population spike. These effects of TRH on LTP were confirmed in a dose-related manner. These results indicate that TRH may have two independent effects in the dentate gyrus, an increase in cellular excitability and a decrease in synaptic plasticity. The latter may be related to the previously reported anticonvulsant effects on kindling.

Animals↗
PubMed1985

Malignant melanoma in the maxillary sinus--a case successfully treated with radiotherapy.

In this paper, we present a case where radiotherapy was very effective against malignant melanoma. We performed a total maxillectomy as the primary treatment, but the tumor recurred rapidly in the operated wound. Then, the patient was treated with 50 Gy in twenty-five treatments. After that, the tumor disappeared remarkably. On the other hand, this malignant melanoma was of the amelanotic type. We carried out a Fontana's stain and electronic microscopy to provide the criteria for the diagnosis of malignant melanoma. The pathological character of this malignant melanoma was investigated.

Aged↗