Search PubMed⌕ Search

Biomedical subjects

S Fujiwara

Publications and source records attributed to S Fujiwara.

At least 523 records · Page 29Linked to original sources
PubMed1983

Nidogen: a new, self-aggregating basement membrane protein.

Nidogen was purified from a mouse tumor basement membrane where it accounted for 2-3% of the total proteins. It was isolated as two forms (A and B) of a monomer (Mr = 80000) each consisting of a single polypeptide chain folded into a globular head connected to a small tail. The B form of the monomer was shown to be capable of aggregating into a nest-like structure (Mr greater than 250000). A smaller form (Mr = 45000) was observed in some of the extracts. The amino acid composition of nidogen was different to that of other basement membrane proteins. It contained about 10% carbohydrate, with N-linked and O-linked oligosaccharide chains in similar proportions. Isoelectrofocussing demonstrated a limited heterogeneity of nidogen with pI in the range 6.5 - 7. Monomeric nidogen failed to interact with other basement membrane components and heparin. Aggregation could be induced by limited proteolysis and was reversed by detergents or high salt concentrations. Together with the observation that most of the nidogen could be solubilized only after destroying the collagenous matrix, the data indicate that aggregation of nidogen reflects an activity involved in matrix assembly. Specific antibodies raised against nidogen did not distinguish between the monomeric and aggregated form of the protein but showed that the fragment was antigenically deficient. These antibodies did not cross-react with collagen type IV, laminin, entactin and heparansulfate proteoglycan. Immunofluorescence staining and absorption studies demonstrated that nidogen is a common component of authentic basement membranes. Larger forms of nidogen (Mr about 100000 and 150000) were found in organ cultures of Reichert's membrane suggesting that it is synthesized in precursor forms.

Animals↗
PubMed1983

Multiplicity-dependent induction of viral capsid antigen in Raji cells superinfected with Epstein-Barr virus.

A quantitative analysis of Epstein-Barr virus (EBV)-induced early antigen (EA) and viral capsid antigen (VCA) syntheses was carried out in Raji cells superinfected with purified, concentrated P3HR-1 EBV. When the cells were exposed to the virus and assessed by immunofluorescence and immunoprecipitation, EA induction occurred significantly (17%) but not VCA (less than 1%), at a low-input multiplicity of infection (MOI) of 10 EBV DNA copies/cell. In contrast, at a high MOI of 500 EBV DNA copies/cell, the majority of cells were positive for both EA (82%) and VCA (61%). The latter VCA synthesis was accompanied by the replication of EBV DNA. Kinetic studies showed that EA induction was directly proportional to the dilution of the infecting virus, while VCA was made following three-hit kinetics. The implications of these results are discussed in relation to the heterogeneous nature of P3HR-1 EBV and a possible role of EA in VCA synthesis.

Antigens, Viral↗
PubMed1983

Results of microsurgical management of ruptured intracranial aneurysms.

The authors report the results of microsurgical management of 209 cases of ruptured intracranial aneurysms. The outcome of the surgery is discussed from the point of view of operative timing, preoperative grade, age and the effect of vasospasm. The operative results at the time of discharge were as follows: 137 excellent cases, 18 good, 31 fair, 8 poor and 15 deaths. The overall mortality rate was 7% and those patients designated as excellent and good who returned to work fully accounted for 74%. The result was achieved even though 65% of the patients were operated on within 2 weeks after the onset, and 44% of the patients were categorized as grade III, IV and V in Hunt's classification. In the morbidity and mortality, over half of the patients categorized as fair, poor and death were complicated by vasospasm, and the result was attributed mainly to the vasospasm. Therefore, we strongly believe that radical surgery is recommended to prevent rebleeding in the waiting period, there should be a greater understanding of "vasospasm" in order to improve overall morbidity and mortality.

Adolescent↗
PubMed1983

Monoclonal antibody specific for capsid antigen of Epstein-Barr virus.

A hybrid cell line (Cl-51) producing an anti-capsid antibody was obtained by fusion of mouse myeloma cells with spleen cells from mice immunized with purified P3HR-1 Epstein-Barr virus (EBV). Immunofluorescence showed that the Cl-51 antibody reacted with the cytoplasm and the nucleus of P3HR-1 and B95-8 cells, but not with Raji, BJAB, Molt-4, and superinfected Raji cells in the presence of cytosine arabinoside (Ara-C). The viable P3HR-1 and B95-8 cells were not stained nor was the viral infectivity neutralized. The Cl-51 antibody immunoprecipitated 123,000 and 120,000 dalton polypeptides of P3HR-1 and B95-8 cells, respectively, and both were sensitive to phosphonoacetic acid. Specific reactions were not evident with extracts of Raji cells and superinfected Raji cells in the presence of Ara-C. An analysis of the purified virus particles showed that this antibody recognized a capsid component of EBV.

Animals↗
PubMed1983

Simultaneous radical surgical treatment for membranous obstruction of the inferior vena cava and the coincident hepatocellular carcinoma--the first successful case.

To our knowledge, this is the first report of a patient for whom a successful radical treatment for both membranous obstruction of the inferior vena cava (MOVC) and coincident hepatocellular carcinoma (HCC) were simultaneously carried out. A 36 year old Japanese man with Budd-Chiari syndrome due to MOVC was found to have HCC in the right hepatic lobe during a shunt operation between the inferior vena cava (IVC) and the right atrium (RA), using a vascular prosthetic graft. He was referred to us from another institute for further operative procedures. Both the mediastinum and the abdomen were entered through a long midline incision with longitudinal splitting of the sternum. The graft that had been occluded by thrombus was removed. Transcardiac membranotomy was achieved by manual manipulation and then by Tubb's dilator. The hepatic tumor with an abundant surgical margin of the liver was resected. The tumor of 2.5 X 2.5 X 2.0 cm was a well differentiated clear cell type HCC associated with congestive liver cirrhosis. Postoperative contrast and pressure studies through IVC showed satisfactory results. Serum alfa-fetoprotein levels decreased from 503 to 12 ng/ml. The patient is well at least for 44 months after the surgery without any recurrence at the time of completion of this writing.

Adult↗
PubMed1983

Acoustic neurinoma presenting as subarachnoid hemorrhage.

A 49-year-old man who had been suffering from disturbance of hearing for 5 years suddenly developed severe headache, nausea, and vomiting. Computed tomography (CT) scans both with and without contrast medium enhancement, performed on the day of admission, showed a nearly round high-density area in the left cerebellopontine angle. A left transaxillary vertebral angiogram showed no aneurysm or arteriovenous malformation. Hemorrhage from a tumor in the left cerebellopontine angle was suspected. CT scan without contrast medium enhancement, performed on the 17th day after onset, showed only a small, ill-defined high-density area in the cerebellopontine angle. An operation was performed on the 20th day after onset. The tumor was totally extirpated together with a clot. Histologically the tumor was an acoustic neurinoma with hemorrhage and necrosis. The postoperative course was favorable. Massive hemorrhage from primary intracranial tumors, especially acoustic neurinomas, is discussed. Radical operation on the tumor should be performed as soon as possible.

Adult↗
PubMed1983

Alcohol sensitivity related to polymorphism of alcohol-metabolizing enzymes in Japanese.

Normal Japanese subjects were divided into two groups, i.e., one with both low and high Km isozymes of aldehyde dehydrogenase for acetaldehyde, and the other deficient in the low Km isozyme. After intake of 0.4 g/kg alcohol, the deficient subjects showed high level of blood acetaldehyde, facial flushing and the other dysphoric symptoms, including increase of pulse rate, decrease of diastolic blood pressure, changes of pulse wave in the fingertip, and elevation of the arterial pressure and blood flow rate in common carotid arteries as well as increase of plasma catecholamines level. In contrast, subjects with normal ALDH did not show these changes. From the observation of liver specimens obtained at autopsy, the frequency of deficient phenotype of ALDH in Japanese was presumed to be about 36%.

Acetaldehyde↗
PubMed1983

Effects of agents that modulate potassium permeability on smooth muscle cells of the guinea-pig basilar artery.

1 Effects of various chemical agents, with known actions on K-permeability, on the membrane potential, membrane resistance and spike activity of smooth muscle cells of the guinea-pig basilar artery were investigated using the microelectrode method. The K-permeability suppressing agents procaine, tetraethylammonium (TEA), 4-aminopyridine (4-AP), and the K-permeability increasing agents acetylcholine (ACh), caffeine and 2-nicotinamidoethyl nitrate (2-NN) were used.2 The mean resting membrane potential of smooth muscle cells was -50.6 mV and was electrically quiescent. The maximum slope of the membrane depolarization produced by a ten fold increase in [K](o) plotted on a log scale was 42 mV. The contribution of the Na-K pump mechanism to the membrane potential was apparent, i.e. the maximum hyperpolarization induced by activation of the Na-K pump was -71 mV. This hyperpolarization ceased following application of ouabain. Reduction in the [Na](o) slightly hyperpolarized the membrane.3 TEA (1-10 mM) and procaine (0.3-10 mM) depolarized the membrane dose-dependently, and increased the membrane resistance. TEA markedly inhibited and procaine slightly inhibited rectification of the membrane.4 Caffeine had dual actions on the membrane potential, i.e. a low concentration (below 1 mM) hyperpolarized the membrane and reduced the membrane resistance, while increased concentrations (above 1 mM) transiently hyperpolarized, and then depolarized the membrane with an increase in the membrane resistance.5 ACh hyperpolarized the membrane dose-dependently (10(-7)-10(-5)M), and reduced the membrane resistance. The hyperpolarizing action of ACh did not persist and even in the presence of ACh, the membrane was repolarized to near the control level.6 2-NN (up to 10(-4)M) and 4-AP (up to 1 mM) did not modify the membrane potential or the membrane resistance.7 TEA (10 mM) generated a spike either spontaneously or by application of electrical stimulation and the spike was preceded or followed by slow oscillatory potential changes. These potential changes ceased with application of diltiazem (10(-5)M).8 Low concentrations of procaine (below 1 mM) accelerated but high concentrations (5-10 mM) inhibited the spike generation in the presence of 10 mM TEA. Low concentrations of caffeine (below 1 mM) inhibited the spike generation and higher concentrations (above 1 mM) of caffeine accelerated the spike generation in the presence of 10 mM TEA. ACh (10(-6)-10(-4)M) consistently inhibited the spike generation, with 10 mM TEA pretreatment.9 4-AP (1 mM) did not modify the membrane potential yet accelerated the spike generation, in the presence of 10 mM TEA. 2-NN (10(-4)M) had no effect on the spike evoked in the presence of 10 mM TEA.10 The results show that the low membrane potential in smooth muscle cells of the guinea-pig basilar artery is mainly due to the low permeability of the membrane to K ion, presumably due to the lack of a K channel sensitive to 2-NN and 4-AP. Similarities and differences between this vascular tissue and other regions are also discussed.

4-Aminopyridine↗
PubMed1983

Nicardipine actions on smooth muscle cells and neuromuscular transmission in the guinea-pig basilar artery.

The effects of nicardipine on smooth muscle cells of the guinea-pig basilar artery were investigated by means of microelectrode and isometric tension recording methods. Nicardipine (1 X 10(-8) to 3 X 10(-6) M) did not modify the membrane potential and resistance of smooth muscle cells. The spike evoked by application of outward current pulse in the presence of tetraethylammonium (greater than 1 X 10(-3) M) was inhibited by 1 X 10(-9) M and was almost blocked by 3 X 10(-7) M nicardipine. Perivascular nerve stimulation evoked the excitatory junction potential which was slightly suppressed by 3 X 10(-6) M nicardipine. The contractions evoked by excess concentration of [K]0, NaCl-free solution or ATP was abolished and by 5-hydroxytryptamine was markedly inhibited in Ca-free ethylene glycol bis(beta-aminoethyl ether)N,N'-tetracetic acid-containing solution, but that induced by caffeine was only slightly inhibited. Nicardipine (greater than 3 X 10(-10) M) markedly inhibited the K-induced contraction noncompetitively as estimated from the Lineweaver-Burk's plot. The ATP-induced contractions were slightly inhibited by nicardipine (greater than 1 X 10(-8) M) to a lesser extent than the K-induced contraction. On the other hand, nicardipine (1 X 10(-6) M) had no effect on the NaCl-free-or 5-hydroxytryptamine-induced contraction. When nicardipine (1 X 10(-6) M) was applied during 2.5 mM Ca loading to muscle cells after depletion of the stored Ca, the subsequently generated caffeine-induced contraction was slightly inhibited due to inhibition of the passive Ca influx. These results indicate that nicardipine possesses a selective inhibitory action for the Ca channel, but the inhibition is limited to particular Ca influxes such as the voltage-dependent one, but not the receptor operated and NaCl-free-induced Ca influxes. This agent acts predominantly on the postjunctional muscle rather than the prejunctional nerve terminal.

Adenosine Triphosphate↗