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Biomedical subjects

M Araki

Publications and source records attributed to M Araki.

At least 163 records · Page 9Linked to original sources
PubMed1990

The essential region for assembly and particle formation in hepatitis B virus surface antigen produced in yeast cells.

The hepatitis B virus (HBV) genome carries a HBV surface antigen (HBsAg) gene that can encode a polypeptide of 226 amino acids (aa). This gene can be expressed in the yeast, Saccharomyces cerevisiae, and the products can be assembled into 22-nm particles indistinguishable from those recovered from a patient's serum. We constructed a set of deletion derivatives of the HBsAg gene, and examined the particle-forming ability of the resulting polypeptides by expressing the gene in yeast. Elimination of 9 aa from the N terminus had no effect, whereas the elimination of 21-80 aa decreased the ability to form particles, and the particles formed were correspondingly smaller. Elimination of 100 aa that delete the major hydrophobic domain of the molecule abolished the ability to form particles completely. Deletion of 53 aa from the C terminus showed little effect. However, deletions proceeding further toward the center of the molecule rendered the polypeptides unstable.

Amino Acid Sequence↗
PubMed1990

Transplantation of the rat pineal organ to the brain: pinealocyte differentiation and innervation.

The pineal organ of neonatal rats was transplanted to the frontal part of the cerebral cortex or the cerebral interhemispheric fissure of an isogenic adult rat to determine whether pineal differentiation and pinealopetal innervation are affected by aberrant neuronal influences. Transplants were fixed for immunohistochemistry at 1, 2 and 6 months after transplantation. When treated with an anti-serotonin antibody, cells in transplants from both locations showed intense immunoreactivity and a morphology comparable to intact pinealocytes, indicating that the transplanted pinealocytes had differentiated normally. Tyrosine hydroxylase immunohistochemistry revealed that new catecholamine fibers of central nervous origin extended only into the periphery and not into the core of transplants grafted within the cortex. However, numerous catecholamine fibers were found in transplants placed in the interhemispheric fissure. These fibers were often accompanied by blood vessels, suggesting that they derived from sympathetic ganglia. Serotonin fibers, which are densely distributed in the cerebral cortex, were seldom found to enter transplants from both locations. These observations indicate that pineal cells express their characteristic properties even when transferred to a foreign milieu and that they do not receive novel innervation from the central nerves that normally do not innervate the intact pineal body; the transplant thereby retains the property of selective pinealopetal innervation.

Animals↗
PubMed1990

Interleukin 3 as a trophic factor for central cholinergic neurons in vitro and in vivo.

We have found that interleukin 3 (IL-3), a growth factor for hematopoietic cells, is a novel trophic factor for mouse and rat central cholinergic neurons. It enhanced neurite outgrowth and elevated choline acetyltransferase activity. The effect seems to be specific for cholinergic neurons, since somatostatin release and glutamic acid decarboxylase and 2',3'-cyclic nucleotide 3'-phosphodiesterase activities were not significantly influenced by IL-3. In vivo, IL-3 was infused into the lateral ventricles of rats after unilateral axotomy of the septohippocampal pathways. Two weeks later, the IL-3-treated animals showed significant numbers of acetylcholinesterase-positive neurons remaining in the septal region.

2',3'-Cyclic-Nucleotide Phosphodiesterases↗
PubMed1990

Norepinephrine suppresses both photoreceptor and neuron-like properties expressed by cultured rat pineal glands.

Our previous study showed that pineal glands of the newborn rat express properties of both photoreceptors and endocrine cells, when transferred to cell culture conditions, whereas opsin was not detected in cells of the intact pineal glands of the postnatally developing or mature rats (Araki et al., 1988). In the present study we asked a question why photoreceptor-like cells do not differentiate in vivo, although the pineal cells have the potency as revealed in cell culture conditions. Our hypothesis was that norepinephrine (NE) may suppress the differentiation of cells with photoreceptor properties. This was proved by adding NE into the culture medium, and only few opsin-like immunoreactive cells, if any, were differentiated in the presence of 10(-6) M NE. NE also suppresses the extension of neurite-like processes by serotonin-like immunoreactive (endocrine) cells, another property expressed in cultures. Other aminergic neurotransmitters, such as dopamine and serotonin, did not have such effects. These results imply that the massive innervations of the pineal gland by the sympathetic ganglion may suppress both photoreceptor and neuron-like properties of the mammalian pineal gland in vivo.

Animals↗
PubMed1990

Differential diagnosis between cyst and tumor. Dentigerous cyst and ameloblastoma containing teeth.

A study was conducted on 21 cases of ameloblastoma (a type of tumor containing an embedded tooth) and 87 cases of dentigerous cyst. The former cases were selected from among those which had been diagnosed histopathologically. Using radiographs of these lesions, the following parameters were measured: 1) the distance between the cement-enamel junction of the embedded tooth and its attachment to the cystic wall; 2) the area of the radiolucent image (similar to the area with a cystic appearance). From measurements of the former parameter, it appeared that the embedded tooth extends more toward the root apex in ameloblastoma than in dentigerous cyst, whereas the latter parameter indicated that the radiolucent area varies in size slightly in ameloblastoma, but tends to be smaller in dentigerous cyst. Moreover, with regard to clustering between ameloblastoma and dentigerous cyst, no definite tendency was detected on distance, whereas only ameloblastoma without dentigerous cyst was seen above 20 cm2 of area.

Adolescent↗
PubMed1990

[Effects of facial nerve denervation on masseter muscle of the rats].

The effects of unilateral facial nerve denervation on the facial growth were studied by physiological and by histochemical examinations, using four- week- old Wistar rats. Two hundred twenty rats were divided into three groups: a control group, a group of subjects which resection of the left facial nerve, and a sham operation group. The rats were killed 1, 5, 10, 30, 60, 90, 120 days later. The superficial and deep masseter muscle fibers on both sides were classified into type I and type IIA or IIB on the basis of myosin ATPase activity and the diameter of these fibers was measured. The masseter muscles were stained with H&E and NADH-TR. Electromyogram recordings were analyzed during the rest position, stretch reflex, voluntary action and eating of solid foods in half of all groups. (1) The face of rats after denervation deviated to the right side, and the maxillo-facial skeleton was affected from the 30th day. (2) In the denervation groups the right side showed higher action potentials than the left side. (3) In the deep masseter muscles near muscle spindle in the denervated groups, the percentage of type I fibers on the right side increased on the 90th day, and that of type IIA fibers decreased on the 30th day. (4) The diameter of the deep masseter muscle fibers, of type I, IIA and IIB increased on the right side. These results prove that facial nerve denervation led to a functional disorder and a transformation of growing direction.

Action Potentials↗
PubMed1990

Localization of iodopsin in the chick retina during in vivo and in vitro cone differentiation.

Using highly specific antibodies against a chick red-sensitive cone pigment, iodopsin, we investigated the localization of iodopsin in the developing and mature chick retina. The chick retina contains several different photoreceptor types, including a rod, a double cone with a principal and accessory cone, and four different types of single cones. Immunocytochemical observations revealed that outer segments (OS) of one of the single cones (type 1) and both cells of the double cone were strongly immunoreactive to anti-iodopsin antibodies. The Golgi regions and small vesicular structures in the inner segments (IS) of these cells also were intensely stained, indicating a continuous synthesis of iodopsin and its addition to the newly formed cone OS. In the differentiating cones of the developing but immature chick retina, iodopsin immunoreactivity was found at the plasma membranes of both the IS and the terminals (pedicles). This suggests that unidirectional transport of iodopsin to the outer segment may be established during cone differentiation. Immunostaining in the outer plexiform layer (OPL) produced two bands, suggesting that the pedicles of the double cones and type 1 single cones terminate at different positions in this layer. Application of the antibodies to a cell culture system of the chick retina revealed that cells immunoreactive to anti-iodopsin differ slightly in morphology from those reactive with anti-rhodopsin. Since antibodies to iodopsin and rhodopsin stained different types of photoreceptors in the intact chick retina, it will be possible to analyze cell lineage of rods and cones in vitro by use of these antibodies.

Animals↗
PubMed1989

Astroglial cell alteration caused by neurotoxins: immunohistochemical observations with antibodies to glial fibrillary acidic protein, laminin, and tyrosine hydroxylase.

Kainic acid or 6-hydroxydopamine (6-OHDA) was injected into rat striatum, and their effects on astrocytes, laminin, and catecholamine fibers were examined temporally by immunohistochemical methods in an attempt to understand the roles of reactive astrocytes and laminin on the restoration of central nervous tissue. Kainic acid injection caused a severe neuronal degeneration in the striatum but catecholamine fibers were spared with only transient loss of tyrosine hydroxylase immunoreactivity. Reactive astrocytes appeared around the lesioned area soon after the kainic acid injection, then migrated into that area, and finally covered the lesioned striatum. Laminin immunoreactivity was found only in the lesioned area before the migration of reactive astrocytes and disappeared when the area was covered by astrocytes. 6-OHDA injection, on the other hand, resulted in a severe degeneration of catecholamine fibers, but striatal neurons were mostly spared. From 7 to 28 days after injection, regenerating fibers were found to enter the affected region. In this period reactive astrocytes were seen in the affected region but were only slightly more numerous than those found in control (saline injected) striatum. Laminin-immunoreactive blood vessels seemed to show a distribution similar to that in control striatum. These observations indicate that reactive astrocytes may play an important role in areas of neuronal cell loss and that laminin may aid their migration into such areas. Laminin and reactive astrocytes may not, however, be essential for the regeneration of dopamine fibers.

Animals↗
PubMed1989

Isolation and Characterization of a Bacteriophage Lytic for Desulfovibrio salexigens, a Salt-Requiring, Sulfate-Reducing Bacterium.

A bacteriophage that lysed Desulfovibrio salexigens cells was isolated from marine sediments and preliminarily characterized by electron microscopy and electrophoretic analysis of structural proteins and genomic nucleic acid. The bacteriophage had an icosahedral head and a long flexible tail, and the buoyant density of the bacteriophage particles was 1.468 g/ml in cesium chloride. The particles consisted of a double-stranded DNA molecule about 33 kilobase pairs long and at least 11 structural proteins.

Journal Article↗
PubMed1989

[Case report of crowding treated without extraction].

In orthodontic diagnosis, one of the most important factors is to decide whether to extract or not to extract the permanent tooth. There are many so-called borderline cases. This difficulty is caused by his growth which can not be foreseen perfectly. We treated a borderline case without extraction, and established good occlusion.

Child↗
PubMed1989

[A case of bronchial asthma and PIE Syndrome induced by disodium cromoglycate].

A 54-year-old female with bronchial asthma and PIE syndrome induced by disodium cromoglycate (DSCG) was reported. She was referred to our hospital for further examination of the abnormal chest shadows and eosinophilia. She had been treated with DSCG, Cefaclor. Bromhexine and bronchodilator for bronchial asthma and bronchitis. Withdrawal of the drugs except for the bronchodilators alleviated her symptoms. Therefore, drug induced lymphocytes stimulation tests (DLST) were performed for those three drugs. Only DLST for DSCG showed a positive result. She had been asthmatic for ten years and treated by the drug for 18 months prior to admission. The skin test for the drug was negative and a precipitating antibody for the drug could not be found. To obtain a definite diagnosis, bronchial challenge by DSCG was performed, after her symptoms were under control. Severe asthmatic responses were provoked in 6 and 24 hours after the inhalation of DSCG. Bronchoalveolar lavage, performed 8 days after the provocation, revealed increased eosinophils and lymphocytes in BAL fluid. Although several cases of PIE syndrome induced by DSCG have been reported, this seems to be the first report of late and delayed type bronchial response and pulmonary infiltration with eosinophilia provoked by DSCG. The bronchial response to the drug was a late and delayed type reaction and sustained for a long period. This might indicate that PIE syndrome induced by the drug may be caused by a same mechanism as the provoked asthmatic response.

Asthma↗
PubMed1989

[Clinical implications of enhanced caffeine contracture in malignant hyperthermia (MH) and Duchenne muscular dystrophy (DMD)].

The caffeine contracture response was studied on the skinned muscle fiber in patients with MH episodes or with DMD. An abnormally enhanced caffeine contracture was observed in 12 out of 14 subjects with MH episodes and 11 out of 13 patients with DMD. The extent of abnormality was almost the same in both group of patients. Ca-induced Ca release (CICR) of the sarcoplasmic reticulum was also analyzed on the same specimens. CICR was increased in 3 out of 4 cases with MH episodes, but it was decreased or unchanged in 4 patients with DMD. It was suggested that the mechanism of abnormal caffeine contracture might not be the same between MH and DMD. Thus, adverse anesthetic reactions, which are occasionally reported in DMD, could be different from genuine MH in its pathophysiology. However, before concluding this issue, further studies seem necessary concerning the molecular mechanism of abnormal Ca release. In the meantime, studies of caffeine contracture on the skinned fiber are helpful as one of predictive tests of MH and related disorders.

Adolescent↗
PubMed1989

[The clinical significance of Creola body in the sputum of asthmatic patients].

In order to clarify the relationship between agglomerated bronchial epithelial cells, i.e. Creola body (CrB), in the sputum and each pathogenetic factor of bronchial asthma, the incidence of CrB in sputum stained by Papanicolaou's method and observed under a light microscope was evaluated in 45 cases of bronchial asthma and 9 cases of obstructive pulmonary diseases. The following results were obtained: 1) CrB was observed specifically in the sputum of patients with bronchial asthma. In comparison with CrB-negative cases, CrB-positive cases had a greater number of days with attacks and a higher incidence of eosinophils in the sputum. 2) The presence of CrB in the sputum tended to be at a high rate in non-atopic cases with low serum IgE values, but had no obvious correlation with either the incidence of neutrophils in the sputum, the present age of the patient, the severity of the disease or bronchial hyperresponsiveness to methacholine. These results suggest that the involvement of histolesionable factors such as persistent bronchial contraction and release of major basic protein from eosinophils in the airway may lead to the formation of CrB.

Adult↗
PubMed1988

Reversed-phase liquid chromatography of the twenty-two tetrachlorodibenzo-p-dioxin isomers on pyrenylethyl- and octadecylsilylated silica gel columns.

To purify the tetrachlorobenzo-p-dioxins synthesized for chemical and biological reference standards, reversed-phase liquid chromatography on pyrenylethyl- and octadecylsilylated stationary phase (PYE and C18) columns was employed with 100% methanol. The pyrenylethyl phase satisfactorily separated isomers resulting from mixtures of reaction products which had not been adequately separated with conventional C18 or silica gel. The use of a single chromatographic mode, liquid chromatography, and a single mobile phase with columns of distinctly different properties, C18 and PYE, separates 20 of the 22 isomers from each other and from the 1246/1249 pair. (The observed properties of the two columns afford insight into steric and polarizability differences among isomers.)

Chromatography, High Pressure Liquid↗
PubMed1988

The efferent projections of the rat lateral habenular nucleus revealed by the PHA-L anterograde tracing method.

The efferent connections of the rat lateral habenular nucleus (LHb) were demonstrated using anterograde transport of the lectin Phaseolus vulgaris leucoagglutinin (PHA-L). Following PHA-L injections into the LHb, neuronal somata located in the lateral two thirds of the LHb were labeled with PHA-L. Individual axonal fibers and terminal specializations were clearly visible. This permitted detailed mapping of both efferent fiber pathways and terminal distributions. Previous reports on fiber pathways were substantially confirmed and several new findings were revealed. (1) Major rostrally oriented fibers enter the medial forebrain bundle via 3 routes which initially branch from the fasciculus retroflexus: the mediodorsal thalamic nucleus and ventromedial thalamic nucleus; the zona incerta and fields of Forel; and the ventral tegmental area of Tsai. (2) A major decussation to the contralateral thalamic nuclei occurs in the central medial thalamic nucleus. (3) Caudally directed fibers follow two courses: one to the deep mesencephalic nucleus, central grey, dorsal raphe nucleus and the deep layers of the superior colliculus; and the other to the median raphe nucleus, oral pontine reticular formation and raphe pontis nucleus. The present results offer more detailed information concerning the dorsal diencephalic system.

Animals↗
PubMed1988

Histochemical observations on unique rod-like cells in the developing retina of the normal rat.

Our previous immunohistochemical studies using specific anti-opsin antibodies have shown that in the normal postnatal rat retina, opsin-like immunoreactive materials can be seen not only in photoreceptor cells but also in some cells of the inner nuclear layer (INL). To characterize these ectopic opsin-like immunoreactive cells further, we have now studied developing rat retinae at the light and electron microscopic levels using both opsin immunocytochemistry and 5'-nucleotidase (5'-N) cytochemistry. Since photoreceptor cells are specifically stained in both methods, we investigated whether these methods would also stain some of the cells in the INL. Opsin-like immunoreactive cells in the INL always showed a characteristic nuclear structure, which was clearly distinguished from that of other INL cells and resembled rod cell nucleus because of the presence of conspicuous masses of condensed heterochromatin. Moreover, these opsin-like immunoreactive cells in the INL occasionally also displayed a ciliary process. They could only be seen in the INL until about day 25 of postnatal life. In the INL, 5'-N activity was found exclusively in cells showing rod-like nuclear features, and the timing of appearance and disappearance of 5'-N-positive cells in the INL was similar to that of the opsin-like immunoreactive cells. Numerous degenerating cells were observed in the INL at around day 10, some of which showed 5'-N reaction product at the cell surface. These results indicate that during postnatal development of the rat retina, some cells in the INL express several phenotypic properties characteristic of rod cells. It is suggested that these cells might undergo either cell degeneration or phenotypic conversion during the subsequent maturation of the retina.

5'-Nucleotidase↗
PubMed1988

Phenotypic expression of photoreceptor and endocrine cell properties by cultured pineal cells of the newborn rat.

Pineal glands of newborn rats were dissociated and maintained under cell culture conditions. The phenotypic expression of both photoreceptor and endocrine cell properties was investigated using immunohistochemical techniques (specific antibodies against opsin or serotonin). After one week in culture, a number of small round cells appeared on top of a sheet of flat epithelium. Among those cells, opsin-like immunoreactive cells were observed. These cells showed a neuron-like morphology with neuritic processes and often formed rosettes. Immunoreactivity was found on the plasma membrane of both the soma and cell processes. Serotonin-like immunoreactive cells were also differentiated in culture with two different morphological types of cells being found. One type resembled cultured serotonin-containing amacrine cells of the retina, and the other type had a flat, polygonal shape similar to that of pinealocytes. Both types of immunoreactive cells possessed fine neuritic processes. These results indicated that cell culture of rat pineal gland cells allowed expression of some properties, such as opsin synthesis and neuron-like morphology with long neuritic processes, that were not expressed in the intact rat pineal gland.

Animals↗