Biomedical subjects

S Furuya

Publications and source records attributed to S Furuya.

At least 55 records · Page 3Linked to original sources

PubMed1998

A novel metabolic communication between neurons and astrocytes: non-essential amino acid L-serine released from astrocytes is essential for developing hippocampal neurons.

A hippocampal astrocyte conditioned medium (HACM) supported the survival of hippocampal neurons under a serum-, glia-free culture setting. The neurotrophic activity in HACM was mostly recovered in low molecular weight fractions (Mr < 3000), which contained high levels of L-serine and L-alanine. However, L-serine alone significantly improved the neuronal survival and neurite growth in a stereo-specific manner. Other non-essential amino acids had no effect. These results strongly suggest that L-serine, released by astrocytes, is essential for the survival and phenotypic growth of hippocampal neurons.

Animals↗

PubMed1998

Application of proton chemical shift imaging in monitoring of gamma knife radiosurgery on brain tumors.

Our objective was to assess proton chemical shift imaging for potential clinical application in monitoring response to gamma knife radiosurgery. Twenty-five proton chemical shift imaging studies and conventional magnetic resonance images were performed on six patients with intracranial tumors. The peak areas of N-acetylaspartate, choline-containing compounds (Cho), creatine, and lipids were calculated and normalized to N-acetylaspartate in the contralateral hemisphere. The spectra from the lesion before treatment showed a relatively high Cho peak, reported as a characteristic spectrum of tumors. Tumor size and Cho level after radiosurgery did not increase except in two cases. In these cases, radiation necrosis was observed with elevated Cho and a mobile lipid peak. Stable or decreased Cho seems to suggest a loss of tumor viability, and changes in Cho indicate the effectiveness of radiosurgery. Increasing Cho and the appearance of the mobile lipid peak may distinguish radiation necrosis from recurrent tumors, which cannot be distinguished by magnetic resonance imaging.

Adolescent↗

PubMed1998

An improved method for culturing cerebellar Purkinje cells with differentiated dendrites under a mixed monolayer setting.

We report here a novel cell culture protocol which facilitates in vitro survival and dendritic differentiation of cerebellar Purkinje cells in a monolayer, mixed culture setting. We found that the type of culture medium is a critical factor for the maintenance of these cells. Purkinje cells present in the single cell suspension of embryonic rat cerebellum were best maintained in a medium based on Dulbecco's modified Eagle's medium (DMEM)/F-12 without the addition of known neurotrophic factors. These cells maintained in DMEM/F-12-based media displayed an approximately 2.5-3.5-fold increase in survival compared with cells maintained in the widely used Basal Medium Eagle's (BME)-based serum-free culture medium with the same supplements. This novel protocol permits not only enhanced survival but also accelerated, improved dendritic differentiation of these cells. Purkinje cells developed highly branched spiny dendrites by 14-16 days in vitro, which matches the time course of the dendritic growth of these cells in vivo. The Purkinje cells expressed metabotropic glutamate receptor 1alpha in the cell bodies and branched dendrites, and the intradendritic calcium concentration increased when trans-ACPD, a selective agonist of this receptor, was applied. This novel protocol allows the development of functional branched dendrites and therefore is useful for electrophysiological and ion-imaging studies on dendrites of Purkinje cells grown in vitro.

Animals↗

PubMed1998

Ceramide and its interconvertible metabolite sphingosine function as indispensable lipid factors involved in survival and dendritic differentiation of cerebellar Purkinje cells.

Ceramide generated from sphingomyelin has emerged as a new but conserved type of biologically active lipid. We previously found that endogenous sphingolipids are required for the normal growth of cultured cerebellar Purkinje neurons and that sphingomyelin is present abundantly in the somatodendritic region of these cells. To gain further insight into a potential role of the sphingomyelin/ceramide pathway, we investigated the effects of depletion of sphingolipids on the phenotypic growth and survival of immature Purkinje cells and the ability of ceramide or other sphingolipids to antagonize these effects. Inhibition of ceramide synthesis by ISP-1, a specific inhibitor of serine palmitoyltransferase, decreased cellular levels of sphingolipids. This treatment resulted in a decrease in cell survival accompanied by an induction of apoptotic cell death and aberrant dendritic differentiation of Purkinje cells with no detectable changes in other cerebellar neurons. Cell-permeable ceramides, sphingosine, or sphingomyelin overcame these abnormalities more effectively than other sphingolipids when added simultaneously with ISP-1. Exposure to bacterial sphingomyelinase in turn enhanced cell survival and dendritic branching complexity of Purkinje cells at different optimal concentrations. Furthermore, cell-permeable ceramide acted synergistically with the neurotrophin family, which has been previously shown to support Purkinje cell survival. These observations suggest that ceramide is a requisite for the survival and the dendritic differentiation of Purkinje cells.

Animals↗

PubMed1998

Thieno[2,3-d]pyrimidine-3-acetic acids. A new class of nonpeptide endothelin receptor antagonists.

On the basis of structural information for the cyclic hexapeptide endothelin (ET) receptor antagonist, TAK-044, a series of thieno[2,3-d]pyrimidine-2,4-dione derivatives bearing a carboxyl group and aromatic rings that were important for receptor binding were designed, synthesized, and evaluated for ET receptor binding affinities and inhibitory activities against ET-induced vasoconstriction. Optimization of each substituent in the thieno[2,3-d]pyrimidine ring led to the discovery of a novel and potent nonpeptide ET receptor antagonist, 6-(4-methoxymethoxyphenyl)-5-methylsulfonylaminomethyl-1-(2- methylthiobenzyl)-2,4-dioxo-1,2,3,4-tetrahydrothieno[2,3-d]p yrimidine-3- acetic acid (32 g), which binded to human ETA and ETB receptor subtypes with affinities (IC50) of 7.6 and 100 nM, respectively. Compound 32 g effectively antagonized ET-induced vasoconstriction and the inhibitory effect mediated by the ETB receptor was more potent than that of bosentan, while the inhibitory effect mediated by the ETA receptor was slightly less potent than that of bosentan.

Acetates↗

PubMed1998

[A lateralized reduction of NAA in a case of corticobasal degeneration (CBD): application of proton magnetic resonance spectroscopy (1H-MRS)].

We studied the application of proton magnetic resonance spectroscopy (1H-MRS) in a case of corticobasal degeneration. A 73-year-old woman was referred to our hospital for dysarthria and clumsiness in right arm movement. Intelligence was normal and neither ideational apraxia or ideomotor apraxia were observed. Her speech was slurred and extremely slow. Neurological findings showed a limitation of ocular upward gaze movement, impaired smooth pursuit in the horizontal gaze, rigidity, limb kinetic apraxia and cortical sensory disturbance in the right arm. Magnetic resonance imaging (MRI) showed diffuse brain atrophy, especially in the left fronto-parietal cortex around the central sulcus. A positron emission tomography (PET) study showed diffuse decrement of cerebral blood flow, dominantly in the left hemisphere. The decrease in the uptake of 18F-Fluoro-deoxyglucose also revealed glucose hypo-metabolism, especially in the left frontal and parietal lobe. 1H-MRS by the multivoxel method showed a decrease in N-acetylaspartate (NAA)/Creatine to 1.0 in the left basal ganglia and temporal lobe, compared to the values between 1.4 and 1.7 in the right basal ganglia. These findings indicated that 1H-MRS might detect neuronal loss or degeneration when MRI showed minimal cortical atrophy. This study, the first application of 1H-MRS in a case of corticobasal degeneration, showed that this method was useful for the evaluation of pathophysiological changes in corticobasal degeneration.

Aged↗

PubMed1998

Coexistence of proguanylin (1-15) and somatostatin in the gastrointestinal tract.

In order to identify proguanylin-secreting cells, we have raised an antiserum against the synthetic fragment of human proguanylin (1-15) and have examined the proguanylin-positive cells in the human and rat gastrointestinal tract by immunohistochemical methods. Numerous proguanylin (1-15)-immunoreactive cells were found in the gastrointestinal tract. They were either pyramidal or spindle shaped in the stomach. Spindle-shaped cells, frequently possessing long slender processes, were located at the base of the pyloric epithelium and did not extend to the lumen. In the duodenum and jejunum, these cells were mostly pyramidal in shape and often had a slender process towards the lumen. The immunostaining was completely blocked by the human proguanylin (1-15) fragment. Paneth and goblet cells were negative against this antiserum. The number of serotonin-positive cells was much larger than that of proguanylin-positive cells in all the segments tested. The number of proguanylin-positive cells decreased from the jejunum to the ileum and very few cells were observed in the colon. In contrast to serotonin-positive cells, most somatostatin-positive cells were also positive for proguanylin. Thus, proguanylin (1-15) or its related protein appears to coexist with somatostatin in intestinal endocrine D cells which may be a source of circulating proguanylin. Proguanylin, like somatostatin, may also regulate intestinal function as a local regulator.

Animals↗

PubMed1997

Evaluation of metabolic heterogeneity in brain tumors using 1H-chemical shift imaging method.

Seventeen brain tumors were measured by 1H-CSI (chemical shift imaging) in a 1.5 T clinical magnetic resonance scanner. The metabolic peaks obtained were evaluated by two methods. One method was to obtain the percentage of each metabolite relative to the combined choline, creatine and NAA peak areas, and the other method was to obtain a ratio of the tumor to contralateral brain. The percentage of choline (%Cho) and choline ratio increased, and the %NAA and NAA ratio decreased in the gliomas and malignant tumors. In relation to grading, %Cho increased but the choline ratio did not. We believed the reason for this was that there were many foci of microscopic necrosis in the glioma grade IV. Free lipids were observed in most of the high grade gliomas and in a malignant tumor. Lactate increased in higher grade tumors. Meningiomas showed the highest %Cho. Statistical differences between the grades of glioma were not detected because many tumors had heterogeneous tissue. One resolution to this problem was metabolite mapping. Mapping of the percentage of metabolites was suitable because it described the regional metabolic changes and the resulting signal to noise ratio was better than that achieved by other methods of evaluation.

Aspartic Acid↗

PubMed1997

Involvement of P2-purinergic receptors in intracellular Ca2+ responses and the contraction of mammary myoepithelial cells.

Mammary myoepithelial cells were isolated and cultured to characterize their properties. The intracellular calcium concentration (Cai2+) was measured using the ratio of fura-2 fluorescence at 340 nm to that at 360 nm (F340/F360), and the contraction was simultaneously monitored by the change of fluorescence intensity at 360 nm (F360). Cultured myoepithelial cells retained their contractile machinery as in the intact tissue. NBD-phallacidin fluorescence, which marks F-actin, and electron microscopy showed abundant bundles of microfilaments in the cytoplasm. Oxytocin (> 0.1 nM) induced an increase in Cai2+ and contraction. The amplitude and time course of the Cai2+ increase were not markedly affected in the Ca2+-free solution. Nifedipine (10 microM) did not affect the response to oxytocin. ATP (>1 microM) induced an increase in Cai2+ and contraction. The response to ATP was not affected by Ca2+ removal, but was suppressed by suramin (100 microM), an antagonist of P2-purinergic receptors. The order of potency of nucleotides to increase Cai2+ was ATP = ADP > UTP > UDP. These findings indicate the presence of P2-purinergic receptors in mammary myoepithelial cells. The results suggest that stimulant-induced Cai2+ increases and contractions are due to release of Ca2+ from intracellular stores in these cells. In addition to the hormonal action of oxytocin, extracellular nucleotides may function as paracrine agents to contract myoepithelial cells in the mammary gland.

Actins↗

PubMed1997

A monoclonal antibody to astrocytes, subepithelial fibroblasts of small intestinal villi and interstitial cells of the myenteric plexus layer.

A monoclonal antibody was developed, using cultured subepithelial fibroblasts of rat duodenal villi as the antigenic material, by in vitro immunization. Hybridomas were selected on cryosections of rat brain and small intestine using indirect immunofluorescence techniques. The monoclonal antibody, termed 8E1, was very useful to label GFAP-positive astrocytes in the adult rat brain, subepithelial fibroblasts of intestinal villi and Thuneberg's fibroblast-like interstitial cells associated with the myenteric plexus layer. These cells are known to be stellate in shape, forming a cellular network with extended cell processes that communicate via gap junctions. Immature astrocytes such as radial fibers were not immunolabeled with mAb-8E1. Immunoelectron microscopy revealed clustered gold labeling of 8E1 antigen on the intermediate filaments of cultured astrocytes and cultured subepithelial fibroblasts. This staining pattern was different from the continuous and linear gold labeling of GFAP and vimentin. MAb-8E1 did not immunoblot purified human brain GFAP nor bovine lens vimentin, and so was not neutralized by preabsorption with these molecules. Immunoblot analysis after SDS-PAGE showed that the antigen recognized by mAb-8E1 was a Mr 50K protein in the rat cerebra, and a Mr 56K protein in the cultured subepithelial fibroblasts. This study showed that astrocytes and some types of stellate cells share distinct antigenic properties in the components of their intermediate filaments.

Animals↗

PubMed1997

Effect and distribution of intravenously injected 125I-guanylin in rat kidney examined by high-resolution light microscopic radioautography.

125I-guanylin was injected intravenously into rats, and their kidney and intestinal tract were processed for light microscopic radioautography using semithin sections to examine the binding sites. Various doses of unlabeled guanylin were also injected to examine the morphological effects of guanylin on the kidney. Dense labeling of silver grains due to 125I-guanylin were observed only in the kidney. In the cortex, silver grains were localized on the luminal side of the proximal tubules at 5-30 min. In the medulla, silver grains appeared at the basal side of the collecting ducts, capillaries and loops of Henle after 5 min. Silver grains then accumulated in the cytoplasm of the collecting ducts after 10 min, and disappeared after 30 min. The cell height of the inner medullary collecting ducts (IMCD) decreased and their luminal spaces increased dose-dependently 5 min after the injection of both labeled and unlabeled guanylin. These structural changes returned to control levels within 30 min. These results indicate a high density localization of guanylin receptors on the luminal surface of proximal tubules in the renal cortex and also rapid excretion of guanylin through the IMCD. The morphological changes of the IMCD suggest a diuretic effect of guanylin.

Animals↗

PubMed1997

Developmentally regulated O-acetylated sialoglycans in the central nervous system revealed by a new monoclonal antibody 493D4 recognizing a wide range of O-acetylated glycoconjugates.

We have previously detected an alkali-labile and developmentally regulated antigen in rat embryonic cerebral cortex, which may be 9-O-acetylsialylated GT3 ganglioside (Hirabayashi Y, Hirota M, Suzuki Y, Matsumoto M, Obata K, Ando S (1989) Neurosci Lett 106:193-98). In this study we established a mouse monoclonal antibody, 493D4, that recognizes 9-O-acetyl GT3 ganglioside, but not non-O-acetyl gangliosides. This antibody also reacted with 9-O-acetyl GD3 to a much lesser extent. By using this antibody, we found that O-acetyl GT3 as well as O-acetyl GD3 were expressed strongly in fetal murine cerebral cortex and decreased to an undetectable level after birth. With the assistance of TLC-immunostaining using 493D4 together with Q-Sepharose column chromatography, O-acetyl gangliosides of bovine brain were purified and the structural analysis showed the presence of O-acetyl GD3, O-acetyl LD1, O-acetyl GD2 and O-acetyl GD1b in the adult brain as extremely minor components. Interestingly, the antibody 493D4 could detect O-acetyl sialoglycoproteins in rat brain tissues. One of the major immunoreactive proteins was shown to be synaptophysin, an integral membrane protein specifically present in synaptic vesicles. This monoclonal antibody was therefore useful for sensitive detection of both O-acetylated gangliosides and glycoproteins with O-acetylated sialic acids.

Acetylation↗

PubMed1997

Modified formalin and methanol fixation methods for molecular biological and morphological analyses.

Several simplified fixation methods were examined to determine their suitability for both molecular biological analyses and morphological study. Fixation with 10% v/v formalin alone at 4 degrees C and containing 5 mmol/L ethylenediamine-N,N,N',N'-tetraacetic acid (EDTA) at room temperature preserved significantly more high-molecular-weight DNA than 10% v/v formalin fixation at room temperature. The morphological differences between tissues fixed using these modified formalin fixation methods and conventional 10% v/v formalin fixation were negligible. Of the dehydration fixatives tested, 100% methanol did not cause regional differences due to artificial tissue shrinkage and the morphology of sections prepared by methanol fixation was preserved consistently better than that of acetone- or ethanol-fixed sections. All three dehydration fixatives preserved relatively higher-molecular-weight DNA and RNA, compared with formalin. Cold formalin, formalin containing EDTA at room temperature and 100% methanol are recommended as standard and additional fixatives routine clinicopathological laboratory use.

Breast↗

PubMed1997

Morphological and pharmacological characterization of guinea-pig prostatic smooth muscle cells in vitro.

BACKGROUND: Prostatic smooth muscle is thought to play a major role in the pathogenesis of bladder outlet obstruction in patients with benign prostatic hypertrophy. However, the physiology of prostatic smooth muscle cells remains largely unknown, in part due to the lack of a suitable model system. We therefore sought to establish an in vitro culture of guinea pig prostatic smooth muscle cells. METHODS: Immature guinea pig prostate was treated by enzymatic digestion and the cells obtained were used to initiate the primary culture. After 3 to 4 passages, cultured smooth muscle cells were examined morphologically by immunocytochemistry and electron microscopy. The contractile properties of cultured smooth muscle cells were also examined. RESULTS: The cultured prostatic cells demonstrated hill and valley morphology, which is a hallmark of smooth muscle cells in vitro, and stained positively for desmin. In addition, electron microscopic examination of ultrastructural morphology revealed myofilaments. Confluent cultures of prostatic smooth muscle cells showed a clear, dose-dependent contractile response to phenylephrine. Furthermore, contraction of the prostatic smooth muscle cells by 10(-6) mol/L phenylephrine was completely inhibited by pretreatment with 10(-6) mol/L terazosin. CONCLUSIONS: An in vitro culture of prostatic smooth muscle cells was established. This culture is likely to provide a powerful tool for elucidating the physiology and pathophysiology of prostatic smooth muscle.

Adrenergic alpha-Agonists↗

PubMed1997

Transurethral balloon laser thermotherapy for urinary retention in patients with benign prostatic hyperplasia who are at high surgical risk.

BACKGROUND: Twelve patients with benign prostatic hyperplasia and urinary retention, who were considered to be poor candidates for prostatectomy, were treated by transurethral balloon laser thermotherapy (TUBAL-T). The mean patient age was 78.9 years (range, 66 to 93 years) and the mean duration of bladder catheterization was 11 weeks (range, 2 to 48 weeks). METHODS: Irradiation into the prostatic tissue was done through 360 degrees with a neodymium: yttrium aluminum garnet (Nd:YAG) laser balloon placed in the prostatic urethra, with pain relief provided by using local topical anesthesia. The total laser dose was from 45,000 to 123,376 J, with an average of 73,089 J. The irradiation time was from 40 to 54 minutes, with an average of 45.2 minutes. RESULTS: Spontaneous voiding became possible in all patients at a mean of 2.8 days (range, 1 to 7 days) after irradiation. The mean catheter-free period was 20.5 months (range, 6 to 34 months), with the longest being 34 months. The international prostatic symptom scores, quality-of-life scores, and peak uroflow rates showed substantial improvement after laser thermotherapy. To date, long-term resumption of spontaneous voiding was successfully achieved in 9 of 12 cases (75%). CONCLUSION: TUBAL-T is safe and effective alternative for treatment of urinary retention in patients with benign prostatic hyperplasia who are considered to be at high surgical risk.

Aged↗

PubMed1997

Hemangioma of the prostatic urethra: hematospermia and massive postejaculation hematuria with clot retention.

The case of a 53-year-old man with hematospermia and massive postejaculation hematuria that caused urinary retention is described. This is the sixth case in the English and Japanese language literature. Cystourethroscopic examination revealed that a solitary raised tumor was present just distal to the vermontanum, and that bleeding was from its apex. Histologic examination of an excisional biopsy sample showed features compatible with hemangioma.

Ejaculation↗

PubMed1997

Neurovascular compression of the rostral ventrolateral medulla related to essential hypertension.

The rostral ventrolateral medulla (RVLM) is thought to serve as a final common pathway for the integration of central cardiovascular information and to be important for the mediation of central pressor responses. An association between essential hypertension and neurovascular compression of the RVLM has been reported. To confirm this relationship and to quantitatively measure the distances between the RVLM and the neighboring arteries, we performed magnetic resonance imaging using a high-resolution 512x512 matrix and magnetic resonance angiography in 49 subjects (21 patients with essential hypertension, 10 patients with secondary hypertension, and 18 normotensive subjects). One patient with essential hypertension was excluded from the evaluations because of inadequate assessment due to poor images. Neurovascular compression of the RVLM was observed in 15 of 20 (75%) patients with essential hypertension. In contrast, neurovascular compression was observed in only 1 of 10 (10%) patients with secondary hypertension and only 2 of 18 (11%) normotensive subjects. The rate of observed neurovascular compression in the essential hypertension group was significantly higher than that in the secondary hypertension group and the normotensive group (P<.01 for both). The distances between the RVLM and the nearest arteries in the essential hypertension group were significantly shorter than those in the other groups (P<.05 for all). On the other hand, the distances between the surface of the medulla oblongata and the nearest arteries did not differ among these three groups. These results suggest that neurovascular compression of the RVLM, but not of the other regions of the medulla oblongata, is particularly related to essential hypertension.

Adult↗

PubMed1997

Preoperative detection of the composition of atherosclerotic plaque in the carotid artery using ultrasonography and magnetic resonance imaging.

Preoperative identification of the components of atherosclerotic plaque was attempted using ultrasonography in five patients and magnetic resonance (MR) imaging in three patients before carotid endarterectomy. The correlation between surgical and histological findings, and preoperative ultrasonography and MR imaging was evaluated. Plaque consisting predominantly of calcification appeared as bright echo on ultrasonography and was tough. Plaque consisting predominantly of hemorrhage was echolucent, appeared as low intensity on T2-weighted MR images and was fragile. Such preoperative assessment of plaque composition using ultrasonography and MR imaging is useful for manipulation of atherosclerotic plaque during carotid endarterectomy.

Aged↗