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Biomedical subjects

K Terayama

Publications and source records attributed to K Terayama.

At least 55 records · Page 3Linked to original sources
PubMed1989

Effects of acute lead acetate exposure on adult guinea pigs: electrophysiological study of the inner ear.

The effects on humans of lead acetate exposure may involve the cranial nerves, since vertigo and sensory neuronal deafness have been reported in lead workers; however, there exist only a few reports concerning the dose effects of lead acetate both on the cochlea and the eighth cranial nerve. The effects of lead acetate on the cochlea and the eighth nerve were investigated systematically using cochlear microphonics (CM), whole-nerve action potential (AP), and endocochlear potential (EP) in guinea pigs (male albino Hartley). Guinea pigs were injected with 2 ml of a 1% solution of lead acetate (20 mg) once a week for 1-5 weeks. The threshold of whole-nerve AP (N1) was elevated by injection of lead acetate, even 40 mg, and whole-nerve AP (N1) output voltage decreased after injection of 100 mg of lead acetate. On the other hand, no change was observed in CM after lead acetate injection (100 mg) or in EP after lead acetate exposure (40 mg). The blood concentrations of lead acetate were as follows (mean): control, 4.5 micrograms/dl; Expt 1, 80 micrograms/dl; Expt 2, 126 micrograms/dl; Expt 3, 142 micrograms/dl. We conclude that dysfunction of the eighth nerve is induced by high-dose lead exposure, but that lead exposure does not induce electrophysiological dysfunction of the organ of Corti and the stria vascularis.

Animals↗
PubMed1989

Genetic studies on ossification of the posterior longitudinal ligament of the spine.

To study the genetic background in ossification of the posterior longitudinal ligament of the spine (OPLL), 1,030 relatives of probands with cervical OPLL in 347 families were investigated by observing their spinal x-ray films, and the following results were obtained. Ossification of the posterior longitudinal ligament was found in 26.15% of the parents of the probands and 28.89% of the siblings of the probands. These prevalences were significantly higher than in the general population. The segregation rate in the siblings corresponded neither with the hypothesis of autosomal dominant inheritance nor with that of autosomal recessive inheritance. The possibility of polygene inheritance was also ruled out, considering the risk of recurrence in the siblings of the probands. However, owing to the segregation rate in the siblings exceeding 0.25 and the high prevalence of OPLL in the parents, OPLL was suggested to be a disorder possibly controlled by autosomal dominant inheritance.

Adult↗
PubMed1989

[Suppressive effect of GABA-containing liposomes on kindled convulsion].

gamma-aminobutyric acid (GABA), a major neurotransmitter in the mammalian brain, may be natural mediator of defence against epileptic activities. When given peripherally, however, GABA itself can cross the blood-brain barrier (BBB) insufficiently. Liposomes (LIPO), being composed of lipid bilayers in which various compounds can be entrapped, have been shown to cross the BBB. Recently, Loeb et al. demonstrated that intraperitoneal injection of GABA entrapped within LIPO (GABA-L) significantly suppresses penicillin- or isoniazid-induced seizures in rats. In the present study, we examined the effect of intraperitoneally administered GABA-L on the kindled amygdala (AM) seizures in addition to the comparative uptake of radioactivity by brain following intraperitoneal administration of 3H-GABA-L or 3H-GABA in rats. Expt. I: Anticonvulsant effect of GABA-L Twelve male Wistar rats weighing 250-300 g were used. Bipolar electrodes made of twisted stainless steel wire 0.2 mm in diameter were implanted into the left AM. All the animals were kindled at the left AM until a stable kindled seizure was evoked for at least five successive days. Subsequently, the stimulus intensity was gradually reduced and the last intensity to induce the kindled seizure was designated as the generalized seizure triggerring threshold (GST). GABA was dissolved in deionized water at a concentration of 0.5 g/ml. GABA-L and LIPO were prepared as follows. 80 mumoles L-alpha-phosphatidylcholine, 22.8 mumoles stearylamine and 11.4 mumoles cholesterol were dissolved in chloroform. After chloroform was removed under a stream of nitrogen gas, dried thin film of phospholipids was formed.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Effects of lead on sialic acid content and survival of rat erythrocytes.

The anemia frequently observed in lead poisoning is thought to result from a shortening of erythrocyte survival in combination with inhibition of hemoglobin synthesis. However, the exact mechanism by which lead shortens erythrocyte survival remains unclear. In the present study, the effects of lead, injected intraperitoneally, on sialic acid content and survival of rat erythrocytes were investigated in order to study the relationship between them. As indices of lead exposure, hemoglobin (Hb) levels, hematocrits (Ht) and blood lead (blood Pb) levels in the injected rats were also examined. Exposure to lead significantly decreased the sialic acid content of the erythrocyte membrane. The decreases in sialic acid content were evident to some extent below a blood Pb level of 100 micrograms/100 ml and generally present at a level of 100 micrograms/100 ml and higher. In the rats exposed to lead a significant negative correlation was found between sialic acid content and the logarithm of blood Pb level. A shortening of erythrocyte survival was also observed in the rats exposed to lead.

Animals↗
PubMed1988

[Ossification of the posterior longitudinal ligament of the lumbar spine].

The ossification of the cervical posterior longitudinal ligament (OPLL) is widely known and studied in Japan where a roentgenological incidence of 2.06% adults affected has been found. Data concerning the ossification of the lumbar posterior longitudinal ligament are few and occasional. An epidemiological survey on lumbar OPLL was performed by the authors in Matsumoto, Japan, on a total of 792 subjects, 554 of whom over the age of 35, by means of X-ray of the lumbar spine. Ossification of the lumbar posterior longitudinal ligament was detected in 23 subjects (2.9%), with no significant difference between males (3.0%) and females (2.8). Lumbar OPLL was absent in the 238 subjects aged less than 34; it was the most prevalent after the age of 45 (5.1% in males and 4.5% in females). The ossification developed in two ways: continuous ossified layer extending over several vertebrae; circumscribed ossification of the ligament corresponding to the level of the intervertebral disk (retrodiscal type). The result of this epidemiological survey showed a roentgenological incidence of lumbar OPLL of the same magnitude than that of cervical OPLL.

Adult↗
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

Effect of lead on electrophoretic mobility of rat erythrocytes.

Lead often affects the erythrocyte membrane. The relationship between the changes in erythrocyte membrane and the anemia caused by lead is still unclear. Initially, the effect of lead injected intraperitoneally on the electrophoretic mobility of rat erythrocytes was investigated in order to study the relationship between them. As indices of lead exposure, hemoglobin (Hb) levels, hematocrits (Ht), delta-aminolevulinic acid dehydratase (ALA-D) activities and blood lead (blood Pb) levels in the injected rats were also examined. Exposure to lead significantly decreased the mobility of rat erythrocytes. The changes in mobility seemed to be less sensitive than those in ALA-D activity, however, the decreases in mobility were simultaneous with or prior to those in Hb level and Ht. The decreases in mobility were evident to some extent below a blood Pb level of 100 micrograms/100 ml and generally present at a level of 100 micrograms/100 ml and over. In the rats exposed to lead a significant negative correlation was found between the mobilities and the logarithms of blood Pb level.

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

Experience with Charnley low-friction arthroplasty in Japan.

Of 300 hips operated upon from 1972 to 1983, 11 were followed for more than ten years and 107 hips were followed for more than five years. Only two hips had late infection and required Girdlestone resection. One hip with mechanical loosening was revised. The Charnley low-friction arthroplasty components have proved suitable and presented no special difficulties for Japanese people and their lifestyle. In the case of a severely anteverted femoral neck, a fixation of the stem was anteverted up to 30 degrees and sustained in good position. Acetabular dysplasia is a particular problem for Japanese surgeons but can be managed effectively by bone grafting procedures.

Adult↗
PubMed1984

Localization of lipid peroxidation products in liposomes after gamma-irradiation.

The distribution of lipid peroxidation products in liposomes after gamma-irradiation at various doses was studied. Increases in thiobarbituric-acid-reactive substances, in the absorbance at 232 nm and in hydroperoxides were observed mainly in liposomal membranes after relatively low doses of irradiation, while carbonyl compounds were distributed both inside and outside the membranes. After higher doses of irradiation, however, the absorbance at 232 nm and the amount of hydroperoxides reached a maximal level in the membrane portion and then decreased when the decomposition products were released from the membranes. Under this condition, malondialdehyde and other carbonyl compounds were increased mainly in the medium of liposomal suspension. These results are discussed with reference to the lipid peroxidation process which is induced quantitatively by ionizing radiation.

Chemical Phenomena↗