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Biomedical subjects

H Sakamoto

Publications and source records attributed to H Sakamoto.

At least 631 records · Page 35Linked to original sources
PubMed1991

Quantification of EEG irregularity by use of the entropy of the power spectrum.

A new method for quantifying irregularity of EEGs is proposed in this study. The entropy, an information measure, determines the uniformity of proportion distribution. The peakedness or flatness of the distribution of the EEG power spectrum, representing EEG rhythmicity, can be measured by the entropy, because the power spectrum consists of proportions of power at each frequency. The irregularity of the EEG was measured by the entropy of the power spectrum, called an irregularity index (II). The II was obtained from the power spectrum at F3, F4, C3, C4, P3, P4, O1 and O2 during rest and mental arithmetic in 10 normal subjects. Relative band powers of delta, theta, alpha and beta bands and alpha peak frequency were also obtained. EEGs during rest were significantly more irregular anteriorly than in the occipital areas. Alpha activity was also more irregular in the anterior region. A greater degree of EEG desynchronization during mental arithmetic was found over the left hemisphere and the right occipital area. The II was more sensitive to such desynchronization than alpha band power and alpha peak frequency. The differences in spectral structures between rest and mental arithmetic conditions, mainly over the left hemisphere, were also confirmed by the Kullback-Leibler information.

Adolescent↗
PubMed1991

Role of prostaglandins in pregnancy-induced hypertension.

Enzymes involved in prostaglandin I2 (PGI2) and thromboxane A2 (TXA2) synthesis were studied in maternal and fetal platelets and venous endothelium from normotensive pregnant controls (n = 70), women with mild preeclampsia (MP, n = 45), and severe preeclampsia (SP, n = 34). Activities of phospholipase A2 (PHA2), cyclooxygenase (PGHS), and PGI2 synthetase (PGIS) or TXA2 synthetase (TXAS) were determined in platelets and in endothelial cells. The PGHS enzyme was studied further by immunoblot methodology. In maternal platelets: Vmax (per 10(-10) mol/mg protein) and Michaelis-Menten constant (Km) (10(-7) mol, mean +/- SEM) of PHA2 were 3.0 +/- 0.8, 3.0 +/- 0.7, and 31.7 +/- 10.9* maximum velocity (Vmax) and 1.8 +/- 0.3, 2.0 +/- 0.8, and 0.8 +/- 0.2 (Km) in normal control (NC), mild preeclampsia (MP), and severe preeclampsia (SP), respectively (*P less than 0.05 against NC). The apparent overall PGHS plus TXAS activity was 10.2 +/- 1.8, 23.8 +/- 7.1, and 68.8 +/- 18.8* (Vmax) and 3.2 +/- 1.3, 5.4 +/- 1.4, and 6.9 +/- 1.2* (Km, *P less than 0.05 against NC). TXA synthesis in fetal platelets demonstrated PHA2 activity of 6.4 +/- 1.4, 12.0 +/- 1.3, and 17.2 +/- 3.2* (Vmax) and 3.5 +/- 0.9, 2.2 +/- 1.5, and 0.7 +/- 0.3* (Km, *P less than 0.05 against NC), respectively, whereas an apparent overall PGHS plus TXAS activity was 18.5 +/- 2.8, 87.5 +/- 12.5*, and 3.6 +/- 0.1* (Vmax) and 4.8 +/- 1.0, 8.8 +/- 1.2, and 0.8 +/- 0.3* (Km, *P less than 0.05 against NC).(ABSTRACT TRUNCATED AT 250 WORDS)

Blood Platelets↗
PubMed1991

Point mutation of c-Ki-ras oncogene in gastric adenoma and adenocarcinoma with tubular differentiation.

The presence of point mutation at codons 12, 13 and 61 of the c-Ki-ras oncogene was investigated in 7 cases of gastric adenoma and 35 cases of gastric adenocarcinoma using DNA samples from formalin-fixed and paraffin-embedded tissues. Oligonucleotides encompassing the three codons were amplified by using the polymerase chain reaction (PCR), and then examined for point mutation by the selective oligonucleotide hybridization technique. Point mutation was detected in three of the 7 adenomas (43%) and three of the 35 carcinomas (9%). All the gastric adenomas showed the histology of tubular adenoma, being very similar to that of colonic adenoma. The 35 cases of gastric adenocarcinoma were classified into 17 cases of differentiated type and 18 cases of undifferentiated type including signet-ring cell carcinoma. The point mutation of c-Ki-ras oncogene was detected only in the differentiated type (3/17, 18%), and there was no case with point mutation in the undifferentiated type. These results suggest that the genetic mechanism of carcinogenesis differs between the differentiated type and the undifferentiated type of gastric adenocarcinoma, and also that c-Ki-ras activation is possibly involved in a relatively early step of the "adenoma-carcinoma sequence," which leads to the development of a portion of differentiated adenocarcinomas in the stomach.

Adenocarcinoma↗
PubMed1991

Effects of clomipramine on the concentrations of catecholamines, indoleamines and their metabolites in 11 rat brain regions.

The effects of clomipramine (CMP) treatment on the brain concentrations of catecholamines, indoleamines and their metabolites were evaluated in 11 rat brain regions. An acute CMP treatment (15 mg/kg) reduced only the 5-hydroxyindole-3-acetic acid (5HIAA) concentrations in all regions. A long-term CMP treatment (14 days, 10 mg/kg/day) decreased the concentrations of dopamine (DA), 5-hydroxytryptamine and 5HIAA in the mesencephalon, and increased the DA concentrations in the hippocampus. In comparison with the values for the long-term treated rats, an acute injection of CMP (15 mg/kg) after a long-term treatment increased the norepinephrine concentrations in the hypothalamus and amygdala, and the concentrations of DA, 3,4-dihydroxyphenylacetic acid and homovanillic acid in the basal ganglia. On the other hand, it failed to decrease the 5HIAA concentrations in the basal ganglia, frontal cortex, hypothalamus, cerebellum, pons + medulla oblongata, and mesencephalon.

Animals↗
PubMed1991

Usefulness of the newly proposed International Classification of Epilepsies, Epileptic Syndromes, and Related Seizure Disorders (1989): a trial on adult patients in a neuropsychiatric clinic.

The utility of the "International Classification of Epilepsies, Epileptic Syndromes, and Related Seizure Disorders," proposed by ILAE in 1989, was investigated in a neuropsychiatric clinic with a patient population numbering 300. Two hundred and three patients (67.7%) had localization-related epilepsies (LRE), including one idiopathic case. Sixty-six patients (22%) had generalized epilepsies, 50 idiopathic, 2 Lennox-Gastaut syndrome, and 14 symptomatic. Thirty-one patients (10.3%) with generalized tonic-clonic seizures occurring only during sleep had the epilepsies undetermined whether they are focal or generalized. In the symptomatic LRE cases, 34 cases could not be classified, and 7 of the cases with frontal lobe epilepsies were difficult to subtype. Eleven of the symptomatic LRE cases had some independent seizures, multiple foci in surface EEGs and were intractable. These cases may be defined as "multifocal epilepsies."

Adult↗
PubMed1991

Malignant mesothelioma of the tunica vaginalis testis. Report of a case and review of the literature.

An autopsy case of malignant mesothelioma of the tunica vaginalis testis in a 60-year-old man is described. The tumor showed widespread metastasis via the lymphatics, leading to the patient's death five years after diagnosis. A review of 38 previously described cases is also presented. The most frequent presenting symptom was hydrocele. When a hydrocele in association with a paratesticular tumor is present, aspiration cytology should be performed first. In most of the cases with a fatal outcome, the tumors metastasized to the retroperitoneal lymph nodes. Once the diagnosis has been made, lymphangiography or CT scan should be done immediately.

Adult↗
PubMed1991

[Individual differences in image and pulse-wave responses elicited by listening to music].

This study was undertaken to clarify individual differences in psycho-physiological responses observed in subjects listening to music. Forty-five healthy females listened to the third movement of Mozart's "Eine Kleine Nachtmusik" via a biaural headphone at 69.4 dB(A) in Leq and 83.6 dB(A) in Lmax. This was undertaken twice with an interval of six days between sessions. Pulse-waves were recorded continuously before, during, and after listening by using a photoelectric plethysmograph. The psychological image each listener had of the music was measured immediately after listening by the SD method composed of fifteen scales with five rating points. The following results were obtained: 1) The pulse-wave height initially became low right after the onset of listening, though the degree of the decrement weakened in the second trial. Spectral analysis of pulse-waves revealed that the power percentage in the low frequency-bands below 0.3912 Hz grew markedly and that in the frequency-bands above 0.4238 Hz it dwindled during and after listening at the first trial. However, these changes of power percentage weakened in the second trial. 2) The image of the music being listened to changed significantly in 11 scales from the first trial to the second trial. 3) Subjects having a previous experience of listening to the music showed smaller image changes and responses in pulse-waves in the second trial than subjects having no such experience. 4) Previous experience of learning any music and the amount of contact with any music were not related to the image changes and pulse-wave responses in the second trial.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Cochlear strial blood circulation.

The present immunohistologic study demonstrates that cochlear strial blood circulation is markedly damaged in guinea pigs subjected to intense acoustic stimulation. In contrast, autonomic unbalance of the inner ear induced by resection or electric stimulation of the superior cervical ganglion has no appreciable effect on cochlear strial blood flow. In consequence, although strial blood circulation in the cochlea is susceptible to pathological change in some conditions, it does not appear to be affected by autonomic unbalance alone.

Acoustic Stimulation↗
PubMed1991

Electron microscopic observation of communication between inner ear stereocilia under normal and noise stimulated conditions.

The ultrastructure of communication between inner ear stereocilia under normal and noise stimulated conditions was studied in the guinea pig. With ruthenium red added to the pre- and post fixation solutions, the connections between the stereocilia could be observed in more detail than with ordinary fixation. After exposure to 1,000 Hz 110 dBSPL sound for 3 h, parts of the connections between the stereocilia had disappeared, and adherence between the adjoining stereocilia was observed. The results of our study lend support to the fact that the congregation of stereocilia after noise stimulation is due to the sticky adjoining stereocilia membrane.

Acoustic Stimulation↗
PubMed1991

Transplacental transfer of kanamycin to the embryonal or fetal inner ear.

Transplacental distribution of kanamycin (KM) to 35-60 day embryonal or fetal inner ear of the guinea pig following maternal treatment was investigated by an immunohistological technique. KM, administered at any stage of pregnancy, migrated through the placenta and entered into the cochlea. The drug pathway to the organ of Corti seemed to consist of two routes: the spiral vessels and the capillaries of the spiral limbus. However, at an early stage of pregnancy, KM was detected only slightly in the area corresponding to the stria vascularis, probably due to immaturation of strial capillaries.

Animals↗
PubMed1991

Whole blood histamine release rate during immunotherapy for nasal allergy.

In treating nasal allergies, desensitization is widely used on a daily basis, and its efficacy has been highly valued. With the purpose of predicting therapeutic efficacy before carrying out immunotherapy, we compared whole blood histamine release rate and various subjective symptoms before and after immunotherapy. We also compared the degrees of efficacy. Immunotherapy brought about a tendency for a reduction in the whole blood histamine release rate. This tendency appeared most marked in those patients in whom an improvement of subjective symptoms was considerable. Among subjective symptoms, the reduction in whole blood histamine release rate was strongest against nasal discharge and sneezing. In patients with a low histamine release rate prior to the initiation of immunotherapy, the improvement in subjective symptoms tended to be low.

Adolescent↗
PubMed1991

Influence of IL-6 on proliferation and differentiation of tonsillar lymphocytes and detection of IL-6 producing cells in tonsil.

When tonsillar B cells were cultured in the presence of exogenous interleukin-6 (IL-6), a small portion of them differentiated into plasma cells which seemed to have IL-6 receptors on their surfaces. The number of plasma cells tended to be greater in the tonsils of children than in the tonsils of adults. When tonsillar cells collected by Ficoll-Conray's method were cultured in medium containing IL-6, T cells differentiated and the number of activated T cells increased. Of the four subsets of T cells, this effect of IL-6 was strongest on cytotoxic T cells. IL-6-mediated proliferation and activation of cytotoxic T cells tended to be greater in the tonsils of children than in those of adults. IL-6 is produced in some tonsillar macrophages. The number of macrophages producing IL-6 was very different in different subjects. However, the number of macrophages producing IL-6 in tonsils of children tended to be greater than the number in tonsils of adults.

Adolescent↗
PubMed1991

Strial circulation impairment due to acoustic trauma.

Blood circulation in the cochlear lateral wall after exposure to a non-physiological level of sound (120-125 dB SPL, 3 h) was investigated immunohistologically. Kanamycin (KM), which was expected to function as a tracer of blood flow, was administered to guinea pigs 5 min to 21 h after sound termination. At 5-30 min, KM was scarce in the capillaries of the stria vascularis (CSVs), whereas abundant KM was present in the spiral ligament vessels. These findings differed markedly from those in non-sound-exposed animals. After the initial period, KM gradually did enter into the CSVs, but its pattern of existence there differed from the normal pattern. These observations suggest that acoustic trauma causes blood stagnation in the strial capillaries, leading to strial dysfunction.

Animals↗
PubMed1991

Surgical treatment of the retethered spinal cord after repair of lipomyelomeningocele.

In a series of 75 patients with surgically treated lipomyelomeningoceles, the neurological condition of six patients deteriorated 6 months to 14 years after the operation due to repeat tethering of the spinal cord. The tethering resulted from postoperative dense adhesion between the cord and the overlying dura mater. Two of the six patients underwent conventional repeat untethering procedures, and the remaining four were successfully treated with a new surgical technique developed by the authors to prevent such dural adhesion. For this procedure, after complete untethering of the spinal cord, the lumbosacral cord is retained in the center of the dural sac by fine stay sutures between the pia mater of the conus medullaris and the ventral dura mater. In addition, the dura mater is tacked to the posterior arch which is reconstructed with bone grafts at one or two bifid vertebral levels. During a postoperative follow-up period of 1 to 3 years, no further deterioration has been observed and magnetic resonance studies have demonstrated a space filled with cerebrospinal fluid (CSF) around the lumbosacral cord. The authors conclude that long-term observation, both neurological and radiological, is essential even after successful repair of a lipomyelomeningocele. This new surgical procedure can maintain a CSF bath around the lumbosacral cord, thus preventing dural adhesion. Application of this technique will hopefully be beneficial in lipomyelomeningocele patients with a high risk of cord retethering after initial repair.

Adolescent↗
PubMed1991

Purification and characterization of beta-N-acetylhexosaminidase from Trichoderma harzianum.

beta-N-Acetylhexosaminidase was produced by Trichoderma harzianum cultivated with chitin as the growth substrate. The enzyme was purified 13.2-fold to homogeneity by ultrafiltration and sequential chromatography on SP-Toyopearl and Sephacryl S-200. The molecular weight of the enzyme was estimated to be about 150,000 by gel filtration. The pH and temperature optima were 4.0-5.5 and 50 degrees C, respectively. The enzyme hydrolyzed N-acetylchitooligosaccharides at the non-reducing ends to release GlcNAc monomer. The enzyme showed a strict substrate specificity to the sugar chains in complex carbohydrates, hydrolyzing only the linkage of GlcNAc beta 1-3Gal, but not hydrolyzing the other linkages such as GalNAc beta 1-3Gal and GlcNAc beta 1-2Man.

Acetylgalactosamine↗
PubMed1991

Thoracic duct cyst of the neck: a case report.

A thoracic duct cyst was excised from the left side of the neck of a 63-year-old woman. It was 6.5cm in length and 3.5cm in width, and was located behind the common carotid artery and jugular vein. The proximal portion of the thoracic duct with a narrowed lumen was in direct contact with the lateral surface of the cyst and the venous angle. The lower end of the cyst extended into the mediastinum to immediately above the aortic arch; the inferior portion of the thoracic duct descended from the bottom of the cyst into the mediastinum behind the aorta. The cyst was unilocular with a fluid content high in triglyceride (3350mg/dl). Its wall was muscular and permeated with lymphatic vessels.

Cysts↗