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Biomedical subjects

K Ohtsuka

Publications and source records attributed to K Ohtsuka.

At least 217 records · Page 12Linked to original sources
PubMed1987

The properties of goal-directed eye movements evoked by microstimulation of the cerebellar vermis in the cat.

The properties of eye movements evoked by microstimulation of the cerebellar vermis, lobules V VII, were investigated in encéphale isolé cats. The evoked eye movements tended to reach the same final goal in the orbit irrespective of initial eye position. The goal position depended on stimulus intensity. In contrast with the monkey, the goal of the eye movement lay within the oculomotor range. The goal position of the eye movements evoked by simultaneous stimuli delivered to two sites corresponded with the point which was obtained by the vectorial addition of the two eye movements evoked by the stimulation of each site. These findings suggest that the cat vermal lobules V VII play an important role in the control of horizontal and vertical eye position in the orbit.

Animals↗
PubMed1987

Changes of heart rate and QT interval at high altitude in alpinists: analysis by Holter ambulatory electrocardiogram.

The purpose of this study is to record continuously electrocardiograms of alpinists during different activities practiced in mountaineering, compare heart rate and QT interval at high altitude with those at sea level, and compare alpinists with nonalpinists. Analysis was attempted on 14 alpinists (9 male, 5 female, ages 26-45) to determine changes in heart rate and QT interval using continuous ambulatory electrocardiograms recorded at sea level and high altitude. Between 1983 and 1984, 9 of 14 alpinists (6 male, 3 female) were subjected to the study at high altitude, that is, at Mt. Kangchenjunga (Himalaya), Mt. Satopanth (Himalaya), and Mt. Jitudake (Butan), 4400 to 7800 m (mean 5710 m). The following were noted: Heart rate at high altitude was significantly higher both in daytime and nighttime. The circadian rhythm of the heart rate disappeared at extremely high altitude in several alpinists. A high correlation was noted between measured QT interval (QTm) and RR interval (r = 0.81, p = 0.005). Nighttime QTm at high altitude was prolonged in comparison with that of daytime so far as the RR interval remained the same. At high altitude, the nighttime corrected QT interval (QTc) was also significantly prolonged in spite of shortened RR interval. The mechanism of QTc prolongation is not clear. Many factors may impact on the QT interval during mountaineering.

Altitude↗
PubMed1987

A radiological population study on the ossification of the posterior longitudinal ligament in the spine.

This paper reports the results of a radiological population study on the ossification of the posterior longitudinal ligament (OPLL) in both the cervical and the thoracic spine among Japanese. The study was carried out in the Yachiho-mura district in the central part of Japan, where 5074 people were living. X-ray examinations were made of 1058 of the people; there were 440 men and 618 women, 50 or more years of age. The roentgenograms showed 34 cases of OPLL in the cervical spine (3.2%): 19 men (4.3%) and 15 women (2.4%). The condition was most frequently observed at the level of C-4. Radiological classification showed 18 cases of the segmental type, 11 of the continuous type, and five of a mixed type. There were eight cases of OPLL in the thoracic spine (0.8%), four in men (0.9%) and four in women (0.6%). OPLL in the thoracic spine was most frequently observed at the midthoracic levels. All eight cases showed a continuous type of ossification. There were three subjects with OPLL in both the cervical and the thoracic spine. Therefore, the number of subjects with OPLL in either the cervical or the thoracic spine was 39 (3.7%) total.

Aged↗
PubMed1987

Ossification of the spinal ligament. A radiographic reevaluation in Bologna, Italy.

A radiographic reevaluation of cervical spine films of 1,258 adult patients and of thoraco-lumbar spine films of 488 of these was performed at the Rizzoli Orthopaedic Institute (Bologne, Italy), in order to detect ossification of the posterior longitudinal ligament (OPLL), the anterior longitudinal ligament (OALL), the yellow ligament (OYL) and the nuchal ligament at the cervical level, and OPLL, OALL and OYL at the thoraco-lumbar level. The incidence of OALL, OYL and ossification of the nuchal ligament corresponded with those previously reported in the literature. Cervical OPLL was found in 1.83%, with a definite prevalence in the 45-64 age group where the figure was 2.83%. This incidence is much higher than that hitherto reported in Caucasians, and is nearly the same as that in Japan. Possible explanations for this discrepancy are proposed.

Adult↗
PubMed1986

[The development of immunoreactive corticotropin-releasing factor (IR-CRF) in the hypothalamus, pancreas and gastrointestinal tract of immature rats].

Corticotropin-releasing factor (CRF), a hypothalamic releasing hormone, is now known to be widely distributed in extrahypothalamic tissues such as the pancreas and gastrointestinal tract. There are, however, no data concerning the development of CRF in the gastrointestinal tract in immature animals. Using a specific RIA technique for rat CRF, we have determined the IR-CRF concentrations in acid extracts of hypothalamic, pancreatic and gastrointestinal tissues in immature rats. Gel filtration of the extracts was also undertaken in order to investigate the molecular characteristics of the IR-CRF in the digestive system. Pregnant rats were decapitated at 20 days of gestation and the male fetuses (1 day before birth) were removed by hysterotomy. The male pups were also killed by decapitation immediately after birth and at 1, 3, 7, 14, 21, 28 and 42 days postnatally. The rats older than 3 days were divided into fed and 15-h-fasted groups. Pups were weaned at 21 days. The hypothalamus, pancreas, gastric antrum, duodenum and proxymal jejunum were removed immediately after decapitation. The individual tissue fragments were homogenized in 2N acetic acid and boiled for 5 min. The homogenates were centrifuged at 15,000g at 4 degrees C for 30 min and supernatants were removed, lyophilized and stored frozen until assay. Gel filtration was performed at 4 degrees C on a Sephadex G-50 (fine) column (1.6 X 82 cm). A 3 ml of sample was applied to the column and eluted with 0.2N acetic acid containing 0.25% BSA. Fractions of 3 ml were collected and stored at -20 degrees C until assay. The reagents for RIA were purchased from Peninsula Lab., INC. (Belmont, CA.). 125I-Tyr degrees-rat-CRF was labelled by chloramine-T method. Rabbit anti-CRF serum was used at the final dilution of 1:33,000. The antigen bound antibody was separated from the free antigen by the double antibody method using goat anti-rabbit IgG serum. The sensitivity of this RIA was 2-4 pg/tube. The average coefficients of variation for interassay and intraassay were 11.2% and 9.0%, respectively. Extracts of the pancreas, duodenum and jejunum of immature rats gave dilution curves that were parallel to the rat CRF standard curve as well as that of the hypothalamus.(ABSTRACT TRUNCATED AT 400 WORDS)

Age Factors↗
PubMed1986

Paradoxical elevations of plasma glucagon levels in patients after pancreatectomy or gastrectomy.

In twenty-five patients undergoing total pancreatectomy (TP), twenty distal gastrectomy (DG) and twenty healthy subjects, effects of oral glucose loading on the plasma glucagon (IRG) levels were determined. Plasma IRG levels were elevated after glucose loading in the TP and DG patients, but not in the healthy subjects. To clarify events related to the elevations in IRG, the plasma IRG components were analyzed by gel filtration in 6 of the TP patients, 5 of the DG patients and 4 of the controls. In the TP group, IRG3500 was not detectable either in the basal state or after glucose loading, while IRG9000 was markedly increased after glucose (p less than 0.002). In the DG group, IRG3500 was significantly suppressed after glucose (p less than 0.05), but IRG9000 was clearly increased (p less than 0.005). In the controls, IRG3500 was suppressed after glucose (p less than 0.05), however, IRG9000 was not detected throughout the examination. Thus, in patients with TP or DG, the essential cause of the high responses of plasma glucagon after oral glucose loading was the increase in IRG9000. Because the food passage route is much the same in TP and DG patients, the IRG9000 elevations are probably related to secretion in the digestive tract.

Adult↗
PubMed1986

Possible cytoskeletal association of 69,000- and 68,000-dalton heat shock proteins and structural relations among heat shock proteins in murine mastocytoma cells.

When murine mastocytoma cells (FMA 1) were heat shocked (42 degrees C for 4 h), nine heat shock proteins (HSPs) were detected by two-dimensional gel electrophoresis. Their apparent molecular weights were 100, 85, 69, 68, 32, 30, and 23 kDa (3 of 23 kDa). The structural homology of 4, 69, 68, 32, and 30 kDa, was demonstrated by two-dimensional tryptic peptide mapping. The 69- and 68-kDa HSPs were purified and rabbit antisera against these HSPs were prepared. A small fraction (less than 10%) of the 69- and 68-kDa HSPs were copurified with the microtubules and were present in the Triton X-100/KCl cytoskeletal fraction as shown by immunoblotting with the antiserum and by peptide mapping. Our results are consistent with the hypothesis of a cytoskeletal role for HSPs.

Animals↗
PubMed1986

An epidemiological survey on ossification of ligaments in the cervical and thoracic spine in individuals over 50 years of age.

An epidemiological survey on ossification of the spinal ligaments was performed on a total of 1,058 subjects over the age of 50 years by means of roentgenography of the cervical and thoracic spine. Ossification of the posterior longitudinal ligament (OPLL) of the cervical spine was detected in 34 subjects (3.2%) with a predilection for men, whereas OPLL in the thoracic spine was found in 8 (0.8%). There were 325 cases (30.7%) of ossification of the anterior longitudinal ligament (OALL) of stage II or above by Forestier's classification in the region from the cervical to thoracic vertebrae, and these cases included a significantly greater number of men. Ossification of the ligamenta flava (OLF) was observed in 48 cases (4.5%). As for the coexistence of ossification of these ligaments, 364 individuals (34.4%) had at least one instance of OPLL and OALL (stage II or above) in the region from the cervical to thoracic spine, and OLF in the thoracic spine.

Cervical Vertebrae↗
PubMed1986

The origin of square wave jerks: conditions of fixation and microsaccades.

The effects of various fixation stimuli on square waves of eye movements were studied in 16 normal subjects. Fixation eye movements were recorded by infrared reflection oculography under visual and nonvisual conditions. The target size was varied from 9 to 72 minutes of arc in four steps. The mean amplitude of the square wave was enlarged more than 0.5 degrees with the targets over 18 minutes of arc and in total darkness. The findings indicate that the square wave jerks are enhanced microsaccades and are closely related to the instability of the fixation eye movements.

Adolescent↗
PubMed1986

[Thermotolerance in normal and tumor tissues].

Thermotolerance, or increased resistance of tissues to hyperthermia following a prior heat treatment, has been demonstrated not only in normal but also in tumor tissues. The kinetics of thermotolerance depends on the prior heating conditions, i.e. the greater the initial heat damage, the greater is the magnitude of thermotolerance and the longer is the time to reach maximum and the time to decay. Although thermotolerance develops less extensively in cultured cells in low pH medium and average tumor tissue pH is lower than the normal tissue pH, the magnitude of thermotolerance in tumor thus far examined is at least equal to that in the normal tissues. It is known that development of thermotolerance is well correlated with enhanced synthesis of heat shock proteins (HSPs). Recently, we purified HSP 70 (70 kilo dalton HSP) and prepared a rabbit antiserum against the HSP 70. In our preliminary experiments, HSP 70 could be detected and analyzed quantitatively not only in cultured cells but also in normal and tumor tissues by immunoblotting using the antiserum.

Animals↗
PubMed1986

[Experience with the familial occurrence of CIIP and review of the literature in Japan].

Recurrent intestinal obstruction for which no underlying cause can be found has been termed "chronic idiopathic intestinal pseudoobstruction (CIIP)" by Maldonado et al. Some clinical features of CIIP have been pointed out in literatures. More often than not, CIIP often shows hereditary occurrence. The authors have summed up twenty-one cases of CIIP reported till 1984 in Japan, In these cases, only one familial occurrence has been reported excluding our own. Our cases were a young woman and her father and they showed clinical features of CIIP and they might have hereditary factors.

Adolescent↗
PubMed1985

Lipid peroxidation caused by chinoform-ferric chelate in cultured neural retinal cells.

Incorporation of chinoform-ferric chelate was demonstrable in cultured neural retinal cells of chick embryos after 1 h of incubation, and the lipid peroxide level in the cells was increased strikingly 1 h thereafter. On the other hand, free ferric ions were scarcely incorporated into the cells, and a significant increase in the lipid peroxide level in the cells was not observed. These data indicate that chinoform is carrier of iron for its passage through cell membranes and that the incorporated iron induces lipid peroxidation which in turn leads to neural cell degeneration.

Animals↗
PubMed1985

Urinary tract dysfunctions in tethered spinal cord syndrome: improvement after surgical untethering.

We reviewed 55 patients with urinary tract dysfunction owing to the tethered spinal cord syndrome, a form of spina bifida occulta with or without mild myelodysplasia, to evaluate the effects of neurosurgical treatment. Of the patients 24 underwent laminectomy with release of a tethered spinal cord and 31 were followed without the operation. Median followup was approximately 5 years. Urological findings at the most recent examination were compared between the 2 groups. In the operated group 5 patients, including 2 with myelodysplasia, apparently were cured of urinary tract dysfunction and 6, including 2 with myelodysplasia, had somewhat satisfactory results, whereas in the unoperated group only 4 patients had satisfactory results and the remainder were unaffected. Urinary tract dysfunction in some patients with spina bifida occulta may be relieved by surgical release of a tethered spinal cord.

Adolescent↗