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Biomedical subjects

A Hirano

Publications and source records attributed to A Hirano.

At least 145 records · Page 8Linked to original sources
PubMed1996

Evidence that glyceraldehyde-3-phosphate dehydrogenase is involved in age-induced apoptosis in mature cerebellar neurons in culture.

Under typical culture conditions, cerebellar granule cells die abruptly after 17 days in vitro. This burst of neuronal death involves ultrastructural changes and internucleosomal DNA fragmentations characteristic of apoptosis and is effectively arrested by pretreatment with actinomycin-D and cycloheximide. The level of a 38-kDa protein in the particulate fraction is markedly increased during age-induced cell death and by pretreatment with NMDA, which potentiates this cell death. Conversely, the age-induced increment of the 38-kDa particulate protein is suppressed by actinomycin-D and cycloheximide. N-terminal microsequencing of the 38-kDa protein revealed sequence identity with glyceraldehyde-3-phosphate dehydrogenase (GAPDH). A GAPDH antisense oligodeoxyribonucleotide blocks age-induced expression of the particulate 38-kDa protein and effectively inhibits neuronal apoptosis. In contrast, the corresponding sense oligonucleotide of GAPDH was completely ineffective in preventing the age-induced neuronal death and the 38-kDa protein overexpression. Moreover, the age-induced expression of the 38-kDa protein is preceded by a pronounced increase in the GAPDH mRNA level, which is abolished by actinomycin-D, cycloheximide, or the GAPDH antisense, but not sense, oligonucleotide. Thus, our results suggest that overexpression of GAPDH in the particulate fraction has a direct role in age-induced apoptosis of cerebellar neurons.

Aging↗
PubMed1996

Substitutions of Ser for Asn-163 and Pro for Leu-264 are important for stabilization of lipase from Pseudomonas aeruginosa.

The lipase gene from Pseudomonas aeruginosa was randomly mutated by error-prone PCR to obtain thermostable mutants, followed by screening for thermostable mutant lipases. Out of about 2,600 transformants, four thermostable clones were obtained. Their nucleotide sequences showed that they had two or three amino acid substitutions. Analysis of the thermal stabilization of these mutant lipases indicated that Asn-163 to Ser and Leu-264 to Pro mutations were essential for the increased stability of the lipase. We expressed a mutant lipase (StLipA-5) having only the Asn-163 to Ser mutation and another (StLipA-6) having only the Leu-264 to Pro mutation in P. aeruginosa PAO1161, purified them, and then confirmed that the temperature which causes a 50% decrease in the activity of the non-treated enzyme on treatment for 30 min was increased by 1.5 and 3 degrees C, respectively, compared to the wild-type enzyme. However, the thermal stability of the mutant lipase (StLipA-7) having both mutations was increased only by 2.5 degrees C. These mutant lipases were stabilized through a decrease in activation entropy. Kinetic studies showed that the Kcat/K(m) values of StLipA-5, StLipA-6, and StLipA-7 were decreased by 14.4, 52.9, and 26.0%, respectively. Interestingly, the pH-stabilities of StLipA-6 and StLipA-7 were also increased, especially at alkaline pH. Based on these results, the tertiary structure and mechanism of stabilization of the lipase were discussed.

Aspartic Acid↗
PubMed1996

Inhibitory effect of a new butadiene derivative on the production of plasminogen activator inhibitor-1 in cultured bovine endothelial cells.

Tissue-type plasminogen activator (t-PA) and its physiological inhibitor, plasminogen activator inhibitor-1 (PAI-1), are known to be synthesized by vascular endothelial cells and to play important roles in regulating the fibrinolytic activity of plasma. We found that a new butadiene derivative, (3E, 4E)-3-benzylidene-4-(3,4,5-trimethoxybenzylidene)pyrrolidine -2,5-dione (T-686), inhibits PAI-1 production without affecting plasminogen activator (PA) synthesis in cultured bovine endothelial cells. T-686 (1-10 microM) dose-dependently decreased the accumulation of PAI-1 in conditioned medium from the treated cells and elevated PA activity in the conditioned medium. Analysis of the conditioned medium by the zymography technique indicated that T-686 decreased the activities of PAI-1 with an M(r) of 55,000 and t-PA/PAI-1 complex with an M(r) of 99,000. Furthermore, T-686 attenuated the augmentation of PAI-1 antigen induced by lipopolysaccharide in the conditioned medium. The decrease of PAI-1 antigen was in parallel with the reduction of the PAI-1 mRNA level (Northern blots). These results suggest that T-686 can promote net fibrinolytic activity through suppression of PAI-1 production without affecting PA elaboration in endothelial cells.

Animals↗
PubMed1996

Intense superoxide dismutase-1 immunoreactivity in intracytoplasmic hyaline inclusions of familial amyotrophic lateral sclerosis with posterior column involvement.

This report concerns retrospective immunohistochemical and immunoelectron microscopic studies on superoxide dismutase-1 (SOD1) in intracytoplasmic hyaline inclusions (IHIs) of the anterior horn cells of three patients with familial amyotrophic lateral sclerosis (ALS) with posterior column involvement. All of the patients were members of the American "C" family. Almost all of the IHIs, present in the soma and cordlike swollen neurites of some affected neurons of the three patients, were intensely stained by an antibody to human SOD1. By contrast, the cytoplasm of anterior horn cells of the ALS patients and of ten control individuals reacted only weakly with the antibody or not at all. Immunoelectron microscopy revealed that the granule-associated thick linear structures that composed the IHIs were intensely labeled by the antibody to SOD1. The IHIs were also positively stained by antibodies to ubiquitin and phosphorylated neurofilament protein, with the distribution of immunoreactivity resembling that seen with the anti-SOD1 antibody. The DNA analysis disclosed a single-site GCC to GTC substitution at codon 4 (Ala4 --> Val) in the SOD1 gene from the brain samples of the patients and from the peripheral blood of their family members. Our results suggest that SOD1 is a component of IHIs and may interact with Ubiquitin and neurofilament protein, and point to the possibility that the presence of intense SOD1 immunoreactivity in the IHIs may be of relevance in processes involving structurally altered SOD1 molecules encoded by the mutated gene.

Aged↗
PubMed1996

Identification of IGF-I in the calvarial suture of young rats: histochemical analysis of the cranial sagittal sutures in a hyperthyroid rat model.

Premature closure of cranial sutures has been known as one of the complications of juvenile or congenital hyperthyroidism. Thyroid hormone is an anabolic agent for bone formation in the early stages of childhood development. In children, excess thyroid hormone acts as an acceleration factor for the skeletal bone, whereas in adult hyperthyroidism, it causes bone mineral loss due to the high turnover rate of bone formation and consequently bone resorption. In addition, there are numerous literature descriptions concerning the interactions among bone metabolism, hormones, and growth factors, among which insulin-like growth factor I (IGF-I) is the most abundantly found growth factor in osteoblasts and in bone models in vivo. We therefore investigated whether or not the cranial sutures show accelerated closure and how the local growth factors or cytokines participate and function in local bone metabolism after administration of exogenous excess thyroid hormone in a rat model. A total of 60 female Wistar rats, aged 10 days, were divided into two groups, the triiodothyronine (T3)-treated group (n = 30, T3 0.1 microgram/gm of body weight per day) and the control group (n = 30, saline vehicle only), and were maintained and subsequently sacrificed at 15, 30, and 60 days. The parameters of cranial width derived from the morphologic measurements of the skull indicated that the lambda-asterion distance at 30 days and the pterion-bregma distance at 60 days in the T3-treated group were significantly decreased compared with those of the control group. Furthermore, the fluorescent histologic findings showed fluorescent labeling with no interruption along the suture edges, suggesting continuous bone formation, and displayed narrowing of the suture gap of the sagittal suture in the T3-treated group. Tartrate resistant acid phosphatase staining showed very little osteoclastic activity in the sagittal suture, especially in the T3-treated group. The intensity of immunohistochemical staining of IGF-I was markedly increased in the suture margins of the T3-treated group. There were no significant differences observed either in the skull base measurements or in the histologic and histochemical findings of the skull base or the coronal suture between the groups. More significantly, excess administration of thyroid hormone enhanced the cranial sagittal suture closure; therefore, it was proposed that local IGF-I plays an important role in sagittal sutural bone formation.

Alkaline Phosphatase↗
PubMed1996

Human cell receptor CD46 is down regulated through recognition of a membrane-proximal region of the cytoplasmic domain in persistent measles virus infection.

Monkey cells persistently infected by measles virus (MV) Biken strain (Biken-CV-1 cells) showed no cytopathic effects and lacked surface expression of a homolog of human cell receptor, membrane cofactor protein CD46. Transfection of a human CD46 gene into these cells induced extensive cell fusion, indicating that down regulation of the endogenous CD46 homolog was essential for the maintenance of a noncytopathic mode of infection. Surface expression of the exogenously introduced human CD46 was also drastically down regulated in the persistently infected cells compared with uninfected cells. The down regulation was specific for CD46 and did not affect surface expression of exogenously introduced CD4. Exogenous human CD46 was synthesized efficiently in the persistently infected cells, but it did not accumulate on the cell surface. Fusion of Biken-CV-1 cells required the extracellular hemagglutinin (H-protein)-binding domain but not the cytoplasmic domain. Replacing the transmembrane and cytoplasmic domains of CD46 with a glycosylphosphatidylinositol anchor did not prevent cell fusion but completely alleviated down regulation of the glycosylphosphatidylinositol-anchored CD46 in Biken-CV-1 cells. Deletion analyses revealed that the membrane-distal sequences of the CD46 cytoplasmic domain were not only unnecessary but also inhibitory for CD46 down regulation. By contrast, the six amino acid residues proximal to the membrane contained a sequence required for CD46 down regulation in the persistently infected cells. These results indicate that CD46 is down regulated in the persistently infected cells by a mechanism that recognizes a membrane-proximal sequence in the CD46 cytoplasmic domain.

Amino Acid Sequence↗
PubMed1996

Immunohistochemical study on superoxide dismutases in spinal cords from autopsied patients with amyotrophic lateral sclerosis.

A role mutations in the superoxide dismutase (SOD)-1 gene in the pathogenesis of amyotrophic lateral sclerosis (ALS) has been discussed. To investigate immunohistochemical alterations of SOD in the spinal cord affected with the disease, we examined 3 patients with SOD1 mutation-associated family with ALS, 20 patients with sporadic ALS and 10 control individuals. Lewy body-like hyaline inclusions (LBHIs) were seen in the anterior horn cells of all the familial patients and 10 of the 20 sporadic patients, while skein-like inclusions (SIs) and Bunina bodies (BBs) were present in the 20 sporadic patients but not in the familial patients. The primary antibodies used for immunostaining were rabbit antisera raised against human SOD1 and SOD2. The anti-SOD1 antibody reacted strongly with all LBHIs of each familial patient and with some LBHIs of each sporadic patient. The cytoplasm of morphologically intact and degenerated spinal cord neurons as well as spheroids seen in the cases examined was only weakly stained by the antibody to SOD1 or not at all. The reactive astrocytes displayed weak to moderate staining for SOD1. The anti-SOD2 antibody strongly immunolabeled the reactive astrocytes and microglia. LBHIs of both familial and sporadic ALS were negatively stained for SOD2. Spinal cord neurons and spheroids of each case exhibited no significant SOD2 immunoreactivity. Neither antibodies reacted with SIs nor BBs. These results indicate that SOD1 may be involved in the formative process of LBHIs especially in familial ALS but not always in that of SIs or BBs, and imply that SOD2 may have no connection with any of these ALS-related abnormal structures.

Adult↗
PubMed1996

Subregional loss of putaminal efferents to the basal ganglia output nuclei may cause parkinsonism in striatonigral degeneration.

In this study, we examined the topographic involvement of the putaminal projection neurons and their axons in the globus pallidus and substantia nigra, which we visualized by calcineurin immunostaining, in the basal ganglia of patients with striatonigral degeneration (SND). In all cases examined, there was a marked decrease in number of calcineurin-immunopositive neurons in the caudal and lateral portion of the putamen. Also, marked depletion of calcineurin-immunoreactive putaminal efferents was consistently present in the posteroventrolateral portions of the globus pallidus interna (GPi) and externa, and in the ventrolateral portion of the substantia nigra pars reticulata (SNr) topographically corresponding to the putaminal lesion. In view of the functional model of the basal ganglia "motor" circuit, these findings suggest that subregional deafferentation of the GPi/SNr (i.e., basal ganglia output nuclei) from putaminal inputs may be responsible for parkinsonism in patients with SND.

Aged↗
PubMed1996

Expression of vascular endothelial growth factor in pediatric and adult cerebral arteriovenous malformations: an immunocytochemical study.

Children and adults may differ with respect to their cerebral vasculature in both normal and pathological states. The authors have identified four pediatric patients in whom a cerebral arteriovenous malformation (AVM) recurred after surgery for removal of the AVM and in whom a normal postoperative angiogram had been obtained. This phenomenon has not been observed in adults. The propensity to regrow a cerebral AVM may reflect a less mature cerebral vasculature and a disregulated angiogenic process. Recently, attention has focused on vascular endothelial growth factor (VEGF) as a possible general mediator of angiogenesis in development and neoplasia. A retrospective immunocytochemical analysis of VEGF expression in AVM tissue was conducted to test the hypothesis that VEGF expression may be found in association with the regrowth of AVMs. The results demonstrate a high degree of astrocytic VEGF expression in four (100%) of four specimens from the initial operation in the children with recurrent AVMs as compared to one (14%) of seven nonrecurrent AVMs in the pediatric and two (25%) of eight adult specimens. All of the specimens from the first operation of the recurrent group demonstrate a clear association of cellular immunoreactivity to the abnormal blood vessels, a relationship that was not observed in the specimens from the nonrecurrent groups. These observations indicate that a humoral mechanism mediated by VEGF may play a role in AVM recurrence.

Adult↗
PubMed1996

[A case of moyamoya disease in the aged associated with cerebral embolism].

We reported a rare case of Moyamoya disease in the aged associated with cerebral embolism. A 76-year-old female was brought into our hospital by ambulance 30 min after an attack of fainting. She had no past history of cerebrovascular disease. On admission her consciousness level was JCS 3-IA and she showed Rt. hemiparesis ECG exhibited Af tachycardia. No abnormal region was recognized on brain CT. Emergency cerebral angiograms (AG) disclosed that unexpectedly she had Moyamoya disease. Stenotic or occluded lesions were seen from bilateral IC terminal portions to MCA and ACA, and basal moyamoya vessels were visualized. Transdural anastomosis was poor and posterior circulation was the main source of collateral flow. Mode of onset and neurological signs suggested that the cause of the attack was Lt. MCA occlusion at its sphenoidal portion by cardiogenic embolism. Superselective endovascular fibrinolysis was carried out by the use of urokinase and low molecular weight Dextran and Lt. MCA was able to be recanalized. She was recovered without neurological deficit. Lt. STA-MCA anastomosis and encephalo-myosynangiosis was performed in the chronic stage because stenosis had remained in Lt. MCA and hypo-perfusion in bilateral frontal lobes was presented on SPECT. Post-operative AG demonstrated that Lt. MCA was occluded but Lt. frontal lobe was supplied with plenty of blood flow from Lt. STA. During the next day morning, she had another attack of fainting and showed moderate consciousness disturbance and motor aphasia. No abnormal change was noticed on brain CT. Emergency AG revealed that Lt. STA had become stuffed up with embolic and bypass flow had disappeared. Superselective endovascular fibrinolysis was able to recanalize the blood flow imperfectly, but mild motor apasia remained due to Lt. frontal infarction.

Aged↗
PubMed1996

Pathology of cerebral metastases.

Important pathologic features of cerebral metastases include the route of spread of tumor cells to the brain, differences among metastases based on location in dura mater, leptomeninges, and brain parenchyma, differences based on primary tumor site, both known and unknown, the means of spread of metastases within the brain, and the brain's reactions to metastases. Immunohistochemistry and electron microscopy are increasingly used in the pathologic evaluation of cerebral metastasis.

Brain Neoplasms↗
PubMed1996

Mesenchymal chondrosarcoma in anterior skull base: case report.

We report the case of a 16-year-old boy who presented with mesenchymal chondrosarcoma involving the ethmoid sinus, right orbit, nasal cavity, and anterior cranial fossa. The tumor was totally resected by craniofacial surgery; the patient's postoperative course was uneventful. Microscopically, the tumor was composed of highly cellular undifferentiated small cells, alternating with zones of cartilaginous tissues. Mesenchymal chondrosarcoma is a rare, aggressive variant of chondrosarcoma, which might be encountered more frequently due to the advances in neuroimaging and surgical procedures.

Adolescent↗
PubMed1996

[Treatment of clinically localized prostatic cancer--endocrine therapy].

We assessed the actuarial survival of 28 patients with localized prostate cancer who were treated with endocrine therapy in comparison with that of 19 patients who had radical prostatectomy between 1972 and 1995. There were no significant differences among the cause-specific curves and clinical disease-free survival of patients treated with endocrine therapy and radical prostatectomy but the all-cause survival curves favored the surgery group. The results of endocrine therapy alone were unsatisfactory for the patients with high grade tumors. In conclusion, the patients with localized prostate cancer at high risk of death from other complications are reasonable candidates for endocrine therapy.

Actuarial Analysis↗