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Biomedical subjects

M Sakai

Publications and source records attributed to M Sakai.

At least 613 records · Page 34Linked to original sources
PubMed1989

[Intra-arterial injection of cisplatin suspension in lipiodol (LPS) for the treatment of advanced hepatocellular carcinoma (stage IV)].

We established a preparation method for the suspension of cisplatin in Lipiodol (LPS) and applied it by intra-hepatic artery injection for the treatment of advanced hepatocellular carcinoma. We defined that stage IV carcinoma as characterized by tumor spread more than one lobe (H4) or by tumor emboli in the major branches of the portal vein (Vp3) or by distant metastasis (M1). According to this definition, 20 patients of stage IV were treated by this therapy, and evaluated the survival using Kaplan-Meier method. A reduction in tumor size more than 25% was observed in 11 of 20 patients (55%). In 4 of these cases (20%), over 50% of tumor reduction was obtained. In 15 patients whose serum alpha-fetoprotein (AFP) levels were higher than 400 ng/ml, a decrease more than 50% was noted in 9 of the 15 patients (60%). Sixty per cent survival rate was obtained at 6 month. A statistical by significant difference was obtained in the survival patterns between this therapy and other intra-arterial chemotherapy. The factors that influenced on the survival significantly were AFP levels (over 10,000 ng/ml), Vp3 and M1. However, tumor size and intrahepatic metastasis, etc. were not significant factors. LPS therapy seemed to be effective to even stage IV hepatocellular carcinoma and could be applied further.

Carcinoma, Hepatocellular↗
PubMed1989

Effect of aminoguanidine on the glycation.

3-Deoxyglucosone, a carbonyl intermediate compound in the Maillard reaction, acts on bovine serum albumin to increase its fluorescence. Aminoguanidine inhibited the increase of fluorescence intensity formed by bovine serum albumin and 3-deoxyglucosone when 3-deoxyglucosone had been preincubated with aminoguanidine. These results suggested that aminoguanidine inhibits the action of 3-deoxyglucosone in the Maillard reaction.

Animals↗
PubMed1989

[Relation of surface texture of fine finishing diamond point for composite resin and polished surface of composite resin].

Distribution of diamond grain size of seven fine finishing diamond points was measured by a digital image analyzer. Also influence of diamond grain size of fine finishing diamond points on finished surface of two types of visible light cured composite resins (semihybrid type and submicron filler type) were investigated. Diamond grain size was almost from 10 to 100 microns 2 in area. Diamond grain size was closely related to the surface roughness of semihybrid type composite resin, although it was not related to that of submicron filler type composite resin. Surface roughness of a submicron filler type composite resin finished at a low speed was less than that at a high speed. Grain size of diamond point and revolution speed may play an important role in surface texture of composite resin.

Composite Resins↗
PubMed1988

Aromatic L-amino acid decarboxylase-immunoreactive neurons in and around the cerebrospinal fluid-contacting neurons of the central canal do not contain dopamine or serotonin in the mouse and rat spinal cord.

Using a specific antibody against each of the 4 catecholamine-synthesizing enzymes, dopamine or serotonin, we compared the localization of these substances in rat and mouse spinal cord with two kinds of fixative, such as paraformaldehyde and glutaraldehyde, and two types of sectioning technique, i.e. cryostat and microslicer. In this study, we demonstrated aromatic L-amino acid decarboxylase (AADC)-like immunoreactivity (LI) in cerebrospinal fluid (CSF)-contacting neurons for the first time in the mouse. These cells and some AADC-immunoreactive cells localized outside the subependymal layer of mouse and rat spinal cord did not show tyrosine hydroxylase-, serotonin- and dopamine-LI with and without colchicine treatment.

Animals↗
PubMed1988

Carnosine-like immunoreactivity in the olfactory bulb of the rat: an electron microscopic study.

Carnosine-immunoreactive primary olfactory nerve terminals are demonstrated in the glomerular layer of the rat olfactory bulb by immunoelectron microscopy. Asymmetrical synapses between dendrites of mitral/tufted cells and that of periglomerular cells could be observed. In the accessory olfactory system, carnosine-like immunoreactivity is also detected in the vomeronasal neurons.

Animals↗
PubMed1988

Tryptophan metabolism in D-galactosamine-induced liver injury.

We have reported that in rats with D-galactosamine-induced liver injury, the serum level of indoleacetic acid (IAA), a metabolite of tryptophan (TRP), increases before the increase in serum transaminase activity. To determine whether this IAA is derived from hepatocytes, isolated hepatocytes were treated with D-galactosamine and loaded with TRP, and the changes in TRP and IAA levels in the culture supernatant of the isolated hepatocytes were measured at various time intervals. As a result, IAA level in the culture supernatant of hepatocytes treated with D-galactosamine and loaded with TRP significantly increased in a time-dependent manner. This indicates that in D-galactosamine-induced liver injury, a metabolic pathway which produces IAA from TRP through tryptamine is present in hepatocytes.

Animals↗
PubMed1988

Effects of superior colliculus lesion upon a black-white discrimination learning in the albino rat with one eye removed at birth.

It has previously been shown that, following original training of a black-white discrimination task, rats with one eye removed at birth (OEB) relearned the task faster than rats monocularly enucleated at three months of age (OET) when relearning was conducted after extirpation of the visual cortex contralateral to the remaining eye. The aim of the present study was to examine the role of the crossed and uncrossed retina-superior colliculus-lateral posterior nucleus of the thalamus-visual cortex pathway in mediation of original learning and relearning of OEBs in comparison with OETs. For this purpose the superior colliculus was destroyed bilaterally either before or after original learning. It was found that SC lesions did not affect original learning nor its retention in both OEBs and OETs, and there was no difference in the learning rate between the two. In relearning, it was also found that only when SC lesions were made before original learning, did OEBs fail to show faster relearning. Based on these findings it was suggested that enhanced functioning of the uncrossed retina-superior colliculus-lateral posterior nucleus of the thalamus-visual cortex pathway in original learning plays an indispensable role in enabling OEBs to relearn the discrimination task faster than OETs.

Animals↗
PubMed1988

Extracellular ATP has a potent effect to enhance cytosolic calcium and contractility in single ventricular myocytes.

The effect of extracellular ATP on the contraction of single rat cardiac myocytes was investigated, together with the effect on the transient change in cytosolic Ca2+ (Cai) elicited by excitation and on the relationship between these two parameters. In unstimulated single myocytes, ATP caused a small increase in Cai (measured as the ratio of fluorescence of Indo-1 at 410 to that at 490 nm. In myocytes bathed in a medium containing 1.0 mM [Ca2+] at 23 degrees C and stimulated at 1 Hz, ATP (1 microM) resulted in a two-threefold increase in amplitude of contraction, as measured by video cinemicrographic techniques. The duration of the Cai-transient was not altered but its amplitude was markedly enhanced, as was the amplitude of contraction. The relation between Cai and contraction-amplitude was not altered by ATP, when measured over a range of extracellular [Ca2+], suggesting that ATP does not affect the myofilament-Ca2+ interaction. The primary site of action of ATP in increasing Cai is at the sarcolemma since the addition to suspensions of myocytes of caffeine (10 mM), which depletes the sarcoplasmic reticulum Ca2+ load, does not prevent the subsequent increase of Cai due to ATP. Further, lowering of the extracellular [Ca2+] to less than 1 microM with EGTA abolishes the response of Cai to ATP, though not the response to caffeine. Thus in rat cardiac myocytes ATP stimulates trans-sarcolemmal influx of Ca2+: ADP, AMP and adenosine are ineffective. ATP markedly augments the amplitude of the Cai transient elicited by electrical stimulation thus rendering it a potent inotropic agent.

Adenosine Triphosphate↗
PubMed1988

Multiple regulatory elements and phorbol 12-O-tetradecanoate 13-acetate responsiveness of the rat placental glutathione transferase gene.

We have analyzed the cis-acting regulatory DNA elements of the placental rat glutathione S-alkyltransferase (GST-P) gene. Various regions of the 5' flanking sequence were fused with a bacterial chloramphenicol acetyltransferase gene. The transcriptional activity of each construct was determined by the transient expression assay after introduction into a hepatoma cell line. Multiple regulatory elements were identified. Two enhancing elements were located 2.5 and 2.2 kilobases upstream from the transcription start site and designated GST-P enhancers I and II (GPEI and GPEII, respectively). A consensus sequence of the phorbol 12-O-tetradecanoate 13-acetate responsive elements was present in the GPEI and at position -61. GPEII contained two of the simian virus 40 and one of the polyoma enhancer core-like sequences. A silencing element was also found 400 base pairs upstream from the cap site. In accordance with the above observation, endogenous GST-P gene was found to be stimulated when the rat fibroblast line 3Y1 was treated with phorbol 12-O-tetradecanoate 13-acetate. Phorbol 12-O-tetradecanoate 13-acetate enhanced the expression of the transfected GST-P gene to a much higher degree in HeLa cells than in the hepatoma cells, which constitutively expressed the endogenous GST-P. The results are discussed in terms of the specific derepression of GST-P gene during hepatocarcinogenesis in the rat.

Animals↗
PubMed1988

Erythroid differentiation factor is encoded by the same mRNA as that of the inhibin beta A chain.

We have isolated a protein that exhibits a potent differentiation-inducing activity toward mouse Friend erythroleukemia (MEL) cells and human K-562 cells. The protein, designated erythroid differentiation factor (EDF), was found in the culture fluid of human THP-1 cells that had been treated with phorbol 12-myristate 13-acetate. EDF is a homodimer with a Mr of 25,000; the Mr of the monomer is 15,500. cDNA clones encoding the Mr 15,500 subunit of EDF from THP-1 libraries were isolated and sequenced. Surprisingly, the sequence of EDF mRNA is identical to that for the beta A subunit of inhibin, a gonadal protein that suppresses the secretion of pituitary follicle-stimulating hormone. Southern blot analysis indicates that only one gene for EDF/inhibin beta A exists in the human genome. When the EDF subunit cDNA was linked to a simian virus 40 expression vector containing the dihydrofolate reductase gene and transfected into Chinese hamster ovary dihydrofolate reductase negative cells, the transformants began to secrete EDF, demonstrating that the cDNA actually encoded the EDF subunit.

Amino Acid Sequence↗
PubMed1988

Levels of glutathione S transferase pi mRNA in human lung cancer cell lines correlate with the resistance to cisplatin and carboplatin.

The amounts of mRNA for glutathione S transferase pi (GST pi) were significantly lower in 3 human small cell lung cancer (SCLC) cell lines than in 3 non small cell lung cancer (NSCLC) cell lines. The sensitivities of the 3 SCLC cell lines to cisplatin and carboplatin were much higher than those of the 3 NSCLC cell lines. These results indicate that low levels of GST pi mRNA expression in SCLC cell lines inversely correlate to high sensitivity to cisplatin and carboplatin, and further suggest that GST pi may play an important role in intracellular inactivation of these drugs.

Carboplatin↗
PubMed1988

A case of pacemaker lead fracture associated with thoracic outlet syndrome.

A pacemaker lead fracture in the left subclavian vein was caused by compression of the clavicle and the first rib; subsequent coil elongation at the same site on the right side was observed in the replacement lead in a patient with thoracic outlet syndrome. Venography showed narrowing of the subclavian vein at the site where the lead abnormalities were observed. This case illustrates that a lead in the subclavian vein can be easily damaged when a patient has thoracic outlet syndrome.

Aged↗