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Biomedical subjects

S Okajima

Publications and source records attributed to S Okajima.

At least 19 recordsLinked to original sources
PubMed1997

Immunocytochemical distribution of Ca(2+)-independent protein kinase C subtypes (delta, epsilon, and zeta) in regenerating axonal growth cones of rat peripheral nerve.

In the peripheral nerve, regenerating axonal sprouts usually emanate at nodes of Ranvier, and extend as growth cones along the inner surface of Schwann cells and/or through Schwann cell columns in the distal nerve segment. In order to elucidate the significance of Ca(2+)-independent protein kinase C in nerve regeneration, localizations of delta, epsilon and zeta subtypes were examined immunocytochemically in sprouts and growth cones of regenerating axons, as well as in normal intact nerves in the rat sciatic nerve. In normal nerves, intense immunoreactivities of delta, epsilon and zeta subtypes were present in axons of both myelinated and unmyelinated fibres. Subcellularly, the distribution of these subtypes in the axoplasm was patchy, and discontinuous in the axolemma and subaxolemmal peripheral zones of myelinated nerves. Some thin myelinated axons showed no immunoreactivity for epsilon subtype. Schwann cells of both myelinated and unmyelinated fibres had moderate immunoreactivities for each subtype. In areas of nerve regeneration, axonal sprouts at nodes of Ranvier, and growth cones extending along Schwann cell basal laminae, had intense immunoreactivities for delta, epsilon and zeta subtypes which are distributed diffusely throughout the axoplasm, and on the entire axolemma. In the sprouts, immunoreactivity for epsilon subtype was strong on the axolemma, but weak or almost absent in the axoplasm. These data, together with those of our previous study, indicate that Ca(2+)-independent protein kinase C subtypes (delta, epsilon and zeta) have basically the same distribution patterns as those of Ca(2+)-dependent subtypes in sprouts and growth cones of regenerating axons, as well as in normal intact axons; albeit epsilon subtype is somewhat different in distribution and intensity from delta and zeta subtypes. It is suggested that Ca(2+)-independent subtypes are involved in maintaining growth cone activities along with the Ca(2+)-dependent subtypes.

Amino Acid Sequence↗
PubMed1997

[Spinal cord ischemia caused by dissecting aortic aneurysm in a patient with acute exacerbation of pulmonary emphysema].

A 61-year-old man with pulmonary emphysema was admitted due to acute exacerbation of chronic respiratory failure and a complaint of chest pain. A chest CT scan on admission showed aneurysmal dissection from the ascending aorta to the descending aorta. Analgesia was noted below the fourth thoracic vertebra, which supplies the accessory respiratory muscles including the intercostal muscles. Even after recovery from circulatory failure, his chest muscles were weak and he could not be removed from mechanical ventilation. An autopsy revealed ischemia of the spinal cord at the T4 level. In contrast, The C3 level of the spinal cord, which supplies the diaphragm, was intact. Paralysis of accessory respiratory muscles including intercostal muscles may have caused the continuation of the respiratory failure. This case shows the importance of accessory respiratory muscles in maintaining chest wall movement in patients with chronic pulmonary emphysema.

Acute Disease↗
PubMed1996

[Study of erythrocyte sedimentation rate in patients with pulmonary tuberculosis].

We studied the erythrocyte sedimentation rate (ERS) and related factors that influence ESR in 326 patients with Pulmonary tuberculosis. The ESR tended to be higher for aged subjects and showed a difference between patients under 59 years old and patients over 60 years old. Besides, patients under 30 years old tended to present lower ESR. It is suggested that they may be under the influence of inapparent infection. For The Japanese Society for Tuberculosis Classification, a significant difference was noted in the extent, but there was no difference about the presence of cavity. A significant correlation was detected between ESE and Gaffky scale, ESR and CRP, and ESR and period until sputum culture became negative. But CRP negative cases were observed in about 28%. CRP alone was not sufficient for the evaluation of the morbid condition of Mycobacterium infection. Receiver-Operator Characteristic curve analysis confirmed that ESR is useful among patients with pulmonary tuberculosis. Therefore evaluation of ESR together with CRP was needed.

Adult↗
PubMed1995

Distribution of protein kinase C (alpha, beta, gamma subtypes) in normal nerve fibers and in regenerating growth cones of the rat peripheral nervous system.

The distribution of protein kinase C (alpha, beta, gamma subtypes) was studied using immunocytochemical techniques in normal nerve fibers and in regenerating sprouts (growth cones) from the nodes of Ranvier following crush injuries to the rat peripheral nervous system. In normal nerves, for each protein kinase C subtype, immunoreactivity was present in both myelinated and unmyelinated axons. In myelinated axons, immunoreactivity for all three subtypes was patchy in the axoplasm and diffuse in the subaxolemmal peripheral zones. No immunoreactivity was found in the microtubule and neurofilament (cytoskeletal) domain. In contrast, in unmyelinated axons, immunoreactivity was distributed diffusely in the axoplasm. Schwann cells of myelinated fibers exhibited protein kinase C immunoreactivity, but those of unmyelinated fibers did not. In regenerating nerves, early sprouts and growth cones extending through the crushed site along Schwann cell basal laminae exhibited intense immunoreactivity for all three subtypes. Immunoreactivity was distributed diffusely throughout the axoplasm of the regenerating sprouts (growth cones), in which microtubules and neurofilaments were very rare. Thus, the subcellular localization of the protein kinase C immunoreactivity in growth cones of early regenerating nerves differed from that of normal parent axons. These findings suggest that protein kinase C (alpha, beta and gamma subtypes), whose subcellular distribution becomes more extensive in regenerating axons, may have important functional roles in axonal sprouting and in the regulation of growth cone activity in the peripheral nervous system.

Animals↗
PubMed1994

137Cs concentration among children in areas contaminated with radioactive fallout from the Chernobyl accident: Mogilev and Gomel oblasts, Belarus.

The level of radiation exposure in children in Belarus caused by the Chernobyl accident was investigated on the basis of whole body 137Cs count. The subjects were 10,062 children (4,762 boys and 5,300 girls) in Mogilev and Gomel, Belarus, who received Chernobyl Sasakawa Health and Medical Cooperation Project health examinations from May 1991 to December 1992 and who were 5-16 y old at the time of examination. The median whole body 137Cs count per body weight varied from 21-48 Bq kg-1 and from 28-126 Bq kg-1 in Mogilev oblast and Gomel oblast, respectively. (The "oblast" is the largest administrative district constituting the country. Belarus consists of 6 oblasts). Corresponding annual effective dose equivalents were all less than the public dose limit of 1 mSv y-1, but the observed levels in the children were considerably higher than the average level of 2.3 Bq kg-1 reported in the past for the former Soviet Union.

Accidents↗
PubMed1994

Motor axon terminal regeneration as studied by protein gene product 9.5 immunohistochemistry in the rat.

Normal intact and regenerating axon terminals up to 30 days after nerve crushing were studied in the rat flexor carpi ulnaris muscle by confocal laser scanning microscopy (CLSM) and electron microscopy using immunohistochemistry for protein gene product 9.5 (PGP 9.5). The motor axons were intensely and homogeneously stained along their entire length. "Three dimensional" organizations of elaborate axon terminals were clearly demonstrated by reconstructing serial optical images obtained by CLSM in normal neuromuscular junctions. In the injured nerve, the earliest regenerating axons could be identified at endplate regions six days after nerve crushing as intensely immunoreactive thin processes which bifurcated in T-shape and formed delicate lace-like terminals. Such lace-like terminals were composed of fine thread-like portions 0.2-0.8 microm in diameter and expanded portions of 2-3 microm in diameter. Electron microscopy revealed that all the axon terminals in the cytoplasm were stained almost homogeneously by PGP 9.5 immunohistochemistry up to their extreme tips. Axon terminals were in direct contact with the basal lamina of the postsynaptic folds, and showed occasional branching. The thin thread-like portions contained no mitochondria but only a few vesicles, where as the expanded portions, abundant mitochondria. And preterminal axons and some expanded portions were abutted by Schwann cells, while thin thread-like portions were exposed with no association with Schwann cells. Twenty to 30 days after crushing injury, regenerating motor axon terminals resumed their mature form in terms of branching elaborations and ultrastructural features. Thus, CLSM of PGP 9.5 immunocytochemistry combined with electron microscopy was able to demonstrate the "three-dimensional" organization of elaborate axon terminals at high resolution in the normal and regenerating neuromuscular junctions. Using this technique, extremely fine processes of axonal terminals were identifiable at the earliest stage of reinnervation.

Animals↗
PubMed1993

Synaptophysin immunocytochemistry in the regenerating sprouts from the nodes of Ranvier in injured rat sciatic nerve.

Following crush injury of rat sciatic nerve, strong synaptophysin immunoreactivity was demonstrated in the regenerating sprouts that emerged from the proximal nodes of Ranvier and in their growth cones that extended through the space between Schwann cell basal lamina and myelin sheath of the parent axon. These findings suggest that synaptophysin is involved in the growth regulation of regenerating sprouts.

Animals↗
PubMed1991

Synthesis and antitumor activity of 20(S)-camptothecin derivatives: carbamate-linked, water-soluble derivatives of 7-ethyl-10-hydroxycamptothecin.

Novel 36 derivatives (6), bonding the phenolic hydroxyl group of 7-ethyl-10-hydroxycamptothecin (4) with diamines through a monocarbamate linkage, were synthesized and their antitumor activity was evaluated in vivo. The derivatives were soluble in water as their HCl salts with the E lactone ring intact and exhibited significant antitumor activity. One of the derivatives, 6-27 showed excellent activity against L1210 leukemia and other murine tumors. The structure of its hydrochloride trihydrate (CPT-11) was determined by spectroscopic and crystallographic methods.

Animals↗
PubMed1991

Changes in sodium-22 turnover and total body potassium in two-kidney, one-clip renovascular hypertension.

Changes in sodium-22 turnover and total body potassium (TBK) were studied during acute (within 2 weeks after clipping) and chronic (12-14 weeks after clipping) phases in two-kidney, one-clip (2k, 1c) hypertensive rabbits by using a whole body counter. Sodium-22 injected intravenously was eliminated more rapidly in hypertensive rabbits than in controls. The biological half-life (BHL) of sodium-22 was shorter in hypertensive rabbits during both acute (p less than 0.05) and chronic phases (p less than 0.001). A significant negative correlation was obtained between the BHL of sodium-22 and blood pressure (r = -0.588, p less than 0.05) in hypertensive rabbits. TBK decreased significantly at the chronic phase in hypertensive rabbits (p less than 0.05), while TBK showed no significant change in controls. Serum sodium and potassium did not change during the observation period. Increased plasma aldosterone concentration was observed during the acute phase in hypertensive rabbits. These results suggested that sodium retention was not a major factor in the acute and chronic phases of 2k, 1c hypertension in rabbits and that pressure natriuresis could explain, at least in part, the lack of sodium retention. Furthermore, there appears to be a derangement in the intracellular potassium metabolism which may be associated with the maintenance rather than the development of hypertension.

Aldosterone↗
PubMed1991

Physical dosimetry at Nagasaki--Europium-152 of stone embankment and electron spin resonance of teeth from atomic bomb survivors.

Gamma-rays from thermal neutron-induced radionuclide of 152Eu in rocks near the ground center of the atomic bomb (A-bomb) explosion (hypocenter) in Nagasaki were measured with a pure germanium semiconductor detector. Depth profiles of 152Eu activity were obtained for 22 core samples taken from stone embankments on both sides of two rivers (the River Shimono-kawa and the River Urakami-gawa) within 500 m of the hypocenter since the activity in the rocks has a history of incident neutron energy. although the activities of the surface sections were varied from sample to sample, the slopes of depth profile in rock and the value of 152Eu activity in the depth of 240-280 mm were similar among the samples taken from the same location. On the other hand, neutron penetrating experiments using both a fast and a thermal neutron reactor were performed to obtain the relationship between the incident neutron energy spectra and the depth profiles of 152Eu activity in rock. The depth profiles in the bomb exposed samples were close to that obtained by using a 10 mm polyethelene moderator in the reactor experiments. Electron spin resonance (ESR) measurements from teeth of A-bomb survivors were carried out to estimate the individual gamma-ray dose of the survivors. The absorbed dose of ten tooth samples was estimated by ESR dosimetry. The results of ESR dosimetry were consistent with the calculations of tissue dose in air of A-bombs and irradiated shielding configuration of individuals.

Electron Spin Resonance Spectroscopy↗
PubMed1990

Measurement of 239Pu in soil and plants in the Nishiyama District of Nagasaki.

Nishiyama district in Nagasaki is located approximately 3000 m east of the hypocenter of the atomic bomb that was dropped on 9 August 1945. This district is also known as an area where there was a concentrated radioactive fallout with the black rain that was carried by a westerly wind. The Nagasaki atomic bomb was a Pu bomb, and the fallout must have included 239Pu without fission in addition to fission products. The presence of 239Pu in Nishiyama district has been confirmed previously. In this study, the distribution of 239 + 240Pu concentration in the uncultivated soil and the transfer factor of 239 + 240Pu to agricultural products in Nishiyama district were examined. The concentration of 239 + 240Pu in the uncultivated soil was 20 Bq kg-1, which was approximately eight times as high as that in the control districts. The transfer factor of 239 + 240Pu to agricultural products was 10(-4) - 10(-3), which was 1/100-1/200 of that of 137Cs.

Agriculture↗
PubMed1990

[Mechanisms of reperfusion injury of rat kidney].

Recently, oxygen free radicals have appeared to play a major role in injury after ischemia, especially that followed by normoxic reperfusion. To clarify the mechanisms of reperfusion injury, the activities of both oxygen radical producing enzymes and radical scavenging enzymes were measured in the ischemic rat kidney followed by reperfusion. All defensive enzymes activities significantly decreased; superoxide dismutase 2.15 +/- 0.14----1.71 +/- 0.11, catalase 186.6 +/- 12.7----116.5 +/- 7.1, glutathione peroxidase 30.0 +/- 2.6----19.1 +/- 2.9, glutathione reductase 118 +/- 5.1----39.9 +/- 6.8 (U/mg protein). Conversion from xanthine dehydrogenase to xanthine oxidase was only 12% of total activity, and all of them were reversible type oxidase. However, it was suggested by the electron spin resonance method that the tissue xanthine oxidase freed of superoxide dismutase could produce oxygen free radicals. In conclusion, reperfusion injury is caused not only by the increase of oxygen free radicals but by the destruction of scavenging systems.

Animals↗
PubMed1989

Long-term tissue distribution and steady state activity ratios of 232Th and its daughters in rats after intravascular injection of Thorotrast.

To estimate the absorbed dose in the critical organs of Thorotrast patients, it is necessary to know not only the distribution and concentration of 232Th but also its daughter nuclides in the body. The present investigation was undertaken in order to clarify the long-term 232Th tissue distribution and steady state activity ratios between subsequent daughters in the critical tissues using about 30 Wister male rats, as a basis for estimating absorbed doses. The tissue distribution of thorium was examined by means of an autoradiography of the whole body and/or the gamma-ray spectrometry at various times during 2 to 24 months following injection. The concentrations of daughter nuclides in tissues were determined by repetitive gamma examination over a period from 1 hr to 35 days after being sacrificed. The data indicate (1) that approximately 90% of injected Thorotrast is retained in the body for a prolonged period, but about 50% of radium and 10% of radon produced from thorium are eliminated from the body, (2) that the mean steady state activity ratios of 224Ra and 212Pb to 228Th for liver are 0.56 and 0.28, and 0.54 and 0.16 for spleen, 0.58 and 0.82 for lungs, respectively, and (3) that the parent 228Th is translocated to the bone.

Animals↗
PubMed1988

The effect of pictorial context on sentence memory in Broca's and Wernicke's aphasia.

Eighteen aphasic patients (8 Broca's and 10 Wernicke's aphasics), 11 right hemisphere damaged patients and 12 normal subjects were tested to assess the effect of pictorial context on verbal memory with a sentence recognition task. The subjects were read aloud a stimulus sentence describing a simple event and simultaneously shown a picture congruent or incongruent with the sentence. Immediately following or after an interval of 30 sec, the subjects were read aloud a second sentence and asked to judge whether this sentence was the same or different from the stimulus sentence. The results indicated that verbal memory was better retained in supportive situations than in distracting situations, and that this contextual effect was greater in aphasic patients than in any of the other groups. Verbal memory declined rapidly after an interval in aphasic patients, but not in normal subjects. The Broca's and the Wernicke's aphasics demonstrated different performance patterns when semantic analysis of sentences was critical.

Aphasia↗