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Biomedical subjects

S Ishida

Publications and source records attributed to S Ishida.

At least 163 records · Page 9Linked to original sources
PubMed1994

Aminated fucoidan promotes the invasion of 3 LL cells through reconstituted basement membrane: its possible mechanism of action.

Fucoidan is reported to have an antimetastatic activity. In the present study, we prepared an amino group-introduced derivative of fucoidan and examined its effect on the invasion of 3 LL cells through a reconstituted basement membrane (MatrigelTM). Unlike native fucoidan, the aminated derivative promoted the tumor cell invasion: maximal promotion (240% of control invasion) was obtained with 5 micrograms/ml. However, with higher concentrations (10-30 micrograms/ml) of the fucoidan derivative, the promotion was gradually reduced to 130% of control. Both native and aminated fucoidans inhibited specifically the attachment of 3 LL cells to laminin. Interestingly, aminated fucoidan, unlike the native one, promoted the tumor cell adhesion to immobilized synthetic laminin B 1 chain peptide, YIGSR, over a concentration range of 0.5-5 micrograms/ml. Higher concentrations (7-20 micrograms/ml) of the aminated derivative suppressed the adhesive ability of 3 LL cells to YIGSR. 3 LL cells secreted a 50-kDa form of urokinase-type plasminogen activator (u-PA) in the culture medium. Addition of aminated fucoidan (5 micrograms/ml) or YIGSR (10 micrograms/ml) resulted in a 1.7-fold increase in u-PA activity. This effect was enhanced up to 3.5-fold when both substances were simultaneously added. The addition of native fucoidan had no effect. The present results suggest that the 67-kDa receptor-mediated binding of 3 LL cells to laminin activates their invasiveness, especially by enhancing the extracellular u-PA levels. Aminated, but not native, fucoidan may act to enhance the laminin-receptor interaction at the limited concentration range.

Amination↗
PubMed1994

A carotenogenic gene cluster exists on a large plasmid in Thermus thermophilus.

In Thermus thermophilus HB27, the crtB gene encoding phytoene synthase was found to exist on the large plasmid, pTT27. One of the carotenoid under-producing mutants, Crt31, carried a derivative of pTT27 (pTT27') in which deletion and inversion were observed near the crtB gene. T. thermophilus HB8 also contained a large plasmid which showed homology to pTT27 and the crtB gene. These results suggested that genes for carotenoid biosynthesis occurred as a cluster on a large plasmid in Thermus thermophilus. This is the first report to show directly that carotenogenesis is plasmid-encoded in microorganisms.

Alkyl and Aryl Transferases↗
PubMed1994

Increased levels of active pertussis toxin may aid a pertussis vaccine to pass the mouse body weight gain test.

The mouse weight gain test was evaluated for its value in toxicity testing for pertussis vaccines. When the reference whole cell pertussis vaccine was tested at dilutions of 1 in 1 and 1 in 16, the mice which received the 1 in 1 dilution achieved the greatest weight gain by the seventh day of injection, although they experienced a more significant weight loss during the first 24 hours than both the normal control mice or those that received the 1 in 16 dilution. A commercial diphtheria-tetanus-acellular pertussis vaccine with an increased level of pertussis toxin activity significantly accelerated the weight gain of mice. The effect was lost by heating the vaccine at 80 degrees C for 2 hours. A 1 micrograms dose of endotoxin induced a significant weight loss in mice during the first 24 hours of injection followed by weight gain at the same rate as that of the normal control. Pertussis toxin accelerated the weight gain of mice at a dose of 2 micrograms to a level exceeding that of the normal control mice throughout the observation period of 11 days. Pertussis toxin, when inoculated with endotoxin, showed a marked effect of helping mice to recover quickly from the endotoxin-induced initial weight loss to the level of those receiving only pertussis toxin. The effect of pertussis toxin on the acceleration of the weight gain of mice showed the possibility of inappropriate interpretation of the test results. It suggests, therefore, the necessity for separate quantitative tests for controlling the vaccine's toxicities.

Animals↗
PubMed1994

Unusual splice sites in the E1A-E1B cotranscripts synthesized in adenovirus type 40-infected A549 cells.

The adenovirus E1 DNA region consists of two transcription units, E1A and E1B. In this paper we report that the E1A-E1B cotranscripts containing sequences of both the E1A and E1B regions are synthesized during adenovirus type 40 (Ad40) infection of A549 cells. Cytoplasmic RNA was isolated from Ad40-infected A549 cells at 24, 72, and 100 h post infection (p.i.). The complementary (c) DNA was synthesized by reverse transcription using an oligo-dT primer and then amplified by the polymerase chain reaction (PCR) using primers derived from the E1A and E1B regions. The cDNAs thus amplified were sequenced either directly or after cloning into bacteriophage M13 vectors. Analysis of cDNA indicated that the E1A-E1B cotranscripts are synthesized at 72 h p.i., but not at 24 or 100 h p.i. Nucleotide sequences of three cDNAs of the E1A-E1B cotranscripts indicated that the cotranscripts originate from the E1A promoter and lack sequences for both the E1A poly(A) site and E1B cap site. The splices create open reading frames for E1A-E1B fused polypeptides around the E1A-E1B junctions in these mRNAs. Most interestingly, the sequence analysis showed that the 5' and 3' splice junctions in the two E1A-E1B cotranscripts do not conform to the splice consensus GT-AG rule. Our results thus suggest that factor(s) which lead to unusual splicing in the E1 mRNAs are present in Ad40-infected A549 cells.

Adenovirus E1A Proteins↗
PubMed1994

Brain perfusion SPECT in a patient with a subtle venous angioma.

Brain SPECT of regional cerebral blood flow using I-123 IMP demonstrated a focally decreased perfusion area immediately adjacent to a venous angioma in a patient with simple partial seizures. A positive correlation was obtained among the location of the venous angioma, the decreased perfusion area on SPECT images, and the electroencephalographic focus. Anomalous venous drainage through a venous angioma may explain a perfusion disturbance in the surrounding brain of the angioma. High-resolution SPECT imaging with magnetic resonance guidance provides useful information on the pathophysiology of venous angiomas.

Adult↗
PubMed1994

Hepatitis C virus particle detected by immunoelectron microscopic study.

To clarify the morphology of hepatitis C virus (HCV), an indirect immunogold electron microscopic study was carried out on two plasma samples with high HCV RNA titres using polyclonal and monoclonal antibodies specific to the putative HCV envelope protein. Spherical virus-like particles, 55 to 65 nm in diameter with spike-like projections, were found in 1.14 to 1.16 g/ml fractions after sucrose density gradient centrifugation. These particles were found only in HCV-infected blood donors and had morphological features similar to those of flaviviruses. Moreover, these particles specifically reacted with the polyclonal and monoclonal antibodies to the putative HCV envelope protein. This is the first known report in which the morphology of the HCV particle is clearly shown.

Antibodies↗
PubMed1994

Inhibitory effect of oversulfated fucoidan on invasion through reconstituted basement membrane by murine Lewis lung carcinoma.

We investigated the effects of native, oversulfated, and desulfated fucoidans and heparin on the invasion of 3 LL cells through Matrigel. Of the four polysaccharides tested, oversulfated fucoidan was the most potent inhibitor of tumor cell invasion and inhibited most potently and specifically the tumor cell adhesion to laminin. Sodium dodecyl sulfate-polyacrylamide gel electrophoretic analysis of the binding of elastase-cleaved laminin to fucoidan- and heparin-Sepharoses showed that both polysaccharides bound to the 62 and 56 kDa fragments. Pretreatment of 3LL cells with native or oversulfated fucoidan reduced their adhesive potency to laminin. The two fucoidans inhibited further the laminin binding of 3 LL cells which had been pretreated with a laminin-based pentapeptide, YIGSR. These results suggest that fucoidan specifically binds to not only the heparin binding domain(s) of laminin but also site(s) other than the cell surface laminin receptor. 3 LL cells secreted a 50 kDa form of urokinase-type plasminogen activator (u-PA). The extracellular level of u-PA activity was increased 1.7 times by addition of laminin but not type IV collagen. Oversulfated fucoidan most potently reduced the increased u-PA levels. Therefore, the reduction in in vitro invasiveness of 3 LL cells in response to either fucoidan or its oversulfated derivative may result from an inhibition of physical interaction between the tumor cells and the Matrigel (laminin), followed by a suppression of the laminin-induced increase in extracellular u-PA.

3T3 Cells↗
PubMed1994

Genetic analysis of equine rotavirus by RNA-RNA hybridization.

Serotype G3 equine rotaviruses isolated in Japan made up a common genogroup and were classified into two different genotypes. The genomes of serotype G3 equine rotaviruses with an identical electropherotype (isolated from 1982 to 1989) were very closely related to each other regardless of the year in which they were isolated. Serotype G3 equine rotavirus BI originating from England belonged to the same genogroup of serotype G3 equine rotaviruses isolated in Japan, although BI was classified as having a different genotype. The genomes of both serotype G10 equine rotavirus R-22 and serotype G10 calf rotavirus were closely related to each other.

Animals↗
PubMed1994

Disposition of glycyrrhizin in the perfused liver of rats.

The disposition of glycyrrhizin (GLZ) in the perfused liver of rats after dosing in the range of 0.5-30.0 mg was investigated and a pharmacokinetic model was devised to interpret the results. The uptake rate of GLZ into the liver with respect to the unbound GLZ concentration (Cf) in the perfusate followed a Michaelis-Menten type equation with a Km,up of 1.17 micrograms/ml and Vmax,up of 13.9 micrograms/min/g of liver. The efflux clearance (0.044 ml/min/g of liver) from the liver was independent of the Cf in the liver. The biliary excretion rate at a steady-state Cf level in the liver followed a Michaelis-Menten type equation with a substrate inhibition constant (Ki,B) of 42.3 micrograms/ml, Km,B of 1.68 micrograms/ml, and Vmax,B of 3.11 micrograms/min/g of liver. The proposed model, with the holding time fitted to biliary excretion at each dose, accurately described both the perfusate concentration-time profile and the cumulative biliary excretion profile.

Animals↗
PubMed1994

Aggregation of DNA enhanced by the protoberberine alkaloids, coralyne and berberine.

The aggregation of DNA caused by coralyne was studied by spectroscopic, viscosity and electric birefringence measurements. Aggregation was markedly enhanced over a narrow range of coralyne to DNA phosphate ratio and then followed by precipitation. The electric birefringence measurements indicated that the ratio at the maximal aggregation varied depending on the concentration of coralyne, finally reaching 1:1 at higher concentrations. The particles (type I) for such enhanced aggregation were estimated to be prolate ellipsoids 1700-4000 A in length with a diameter of 1400-4000 A. At higher coralyne concentrations, another particle (type II) was formed which was a thick rod-like particle 1700-4000 A in length with a diameter of 120-210 A. These dimensions indicate that type I and II particles consist respectively of several tens of thousands and some hundreds of molecules of DNA. On the other hand, berberine did not produce such a marked aggregation of DNA, and the result was a thick rod-like particle 1700-4000 A in length with a diameter of 300-1000 A. The enhancement by coralyne and berberine is discussed in terms of intermolecular interactions.

Animals↗
PubMed1994

[Application of the Limulus test for practical quality control on endotoxin content in commercial human serum albumin (HSA) products. In comparison with the rabbit pyrogen test].

The bacterial endotoxin content in human serum albumin (HSA) products measured by two different Limulus amebocyte lysate (LAL) test methods, colorimetric and kinetic turbidimetric methods, were compared. So far as endotoxin-specific LAL reagents which do not show a false-positive reaction with (1-->3)-beta-D-glucan are used, a definite correlation was found between the results with the two LAL test methods. Endotoxin added to HSA products was recovered in a quantitative manner showing neither inhibition nor enhancement by HSA to the both LAL test methods. Results of the LAL tests showed a significant correlation with that of the rabbit pyrogen test. The correlation was much improved with endotoxin-added HSA. The present results indicate the practical applicability of the LAL test as an alternative method for the rabbit pyrogen test.

Animals↗
PubMed1994

Rapid free radical reduction in the perfused rat liver.

The reduction of nitroxide free radicals was investigated in detail by Electron Paramagnetic Resonance (EPR) spectroscopy in perfused liver. The nitroxide free radical was rapidly reduced to the corresponding hydroxylamine more efficiently at the lower flow rate of 8 [ml/min], while at higher flow rates, the amount of reduced nitroxide showed a significant decrease. Oxidation of hydroxylamine using hydrogen peroxide provided dynamic information concerning the reduction of the free radical within the liver. In addition, liver homogenates were also investigated to determine the level of nitroxide uptake. The results suggested that a portion of the infused nitroxide was taken up by the liver and cleared from the circulation.

Animals↗
PubMed1994

[Periodical blood pressure variation during cardiopulmonary bypass--effects of cervicothoracic epidural anesthesia and phentolamine].

We studied the effects of cervicothoracic epidural anesthesia or intravenous phentolamine on periodical blood pressure variation during cardiopulmonary bypass in 12 adult patients undergoing open heart surgery under fentanyl anesthesia. Spontaneous periodical fluctuation of the blood pressure was analyzed by means of autoregressive power spectrum method. Amplitudes of the low frequency (0.02-0.15 Hz) component of the blood pressure variation amplitudes were calculated. The amplitudes decreased significantly 10 minutes after cervicothoracic epidural block with 15 ml of 2% lidocaine solution (P < 0.05), and after infusion of 0.4 mg.kg-1 of phentolamine (P < 0.05). Since amplitudes of the blood pressure variation were reduced by adequate epidural block or phentolamine, they are likely to reflect sympathetic vasomotor activity.

Adult↗
PubMed1994

[An adult case of tethered cord syndrome with lipoma and thoraco-lumbar syringomyelia presenting slow progressive muscular atrophy in the lower limbs].

A 23-year-old man developed slowly progressive muscle weakness from the age of 10, followed by paresthesia and urinary disturbance. The physical examination showed bilateral muscular atrophy in the lower limbs and dissociated sensory disturbance below Th8. Although there was normal appearance of spinal X-P, MRI revealed conus medullaris at S2 involved thoraco-lumbar syringomyelia with extramedullary lipoma. After the operation for laminectomy of L5-S2 and untethering without direct surgery for syringomyelia, post-operated MRI exhibited definite shrinkage of the syrinx. It suggested that thoraco-lumbar syringomyelia in the present case was not congenital anomaly, but secondary outcome to tethered cord syndrome.

Adult↗