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Biomedical subjects

Y Sakai

Publications and source records attributed to Y Sakai.

At least 757 records · Page 42Linked to original sources
PubMed1988

Determination of FDP in human plasma by a novel latex immunoassay.

Distribution analyzing latex immunoassay (DALIA), a sensitive method based on the agglutination of latex particles coated with monoclonal antibody, was developed for determination of fibrin degradation products (FDP) in human plasma. The agglutination is measured by using an electric particle counter designed for medical research to determine the volume-ratio of agglutinated to non-agglutinated particles. Interference by serum constituents is avoided by coating the particles with the F(ab')2 fragments of monoclonal antibody and by using suitable latex particles. This assay enabled the determination of FDP in concentrations of 16 to 4000 ng/ml in less than 15 minutes. The mean concentrations of FDP in the plasma of 98 normal subjects and 142 patients with apparent disseminated intravascular coagulation (DIC) were 0.69 and 13.24 micrograms/ml, respectively. Analytical recovery of FDP in plasma samples averaged 104%. The correlation coefficient of DALIA with enzyme immunoassay using two monoclonal antibodies, was 0.809. The results obtained by analyzing the cross-reactivity with related components of FDP and the inhibitory effect of D monomer indicated that the present method can effectively detect the high molecular weight (HMW) fragments of FDP produced in the early stage of plasmin digestion.

Antibodies, Monoclonal↗
PubMed1988

Sensitive serum markers for detecting pancreatic cancer.

Serum amylase, immunoreactive elastase (IRE), carcinoembryonic antigen (CEA), and carbohydrate antigen (CA 19-9) were measured in 40 patients with pancreatic cancer. IRE and CA 19-9 were further assayed in nonpancreatic malignancies (n = 98) and chronic nonmalignant disease (n = 194). In pancreatic cancer, elevated values were observed for amylase in 30% of the patients, for IRE in 70%, for CEA in 28%, and for CA 19-9 in 68%. Elevation of IRE and/or CA 19-9 was found in 95% of the 40 patients. Elevated serum IRE was observed more frequently in head cancer and resectable cancer, whereas elevation in CA 19-9 occurred more often in body-tail cancer and unresectable cancer. Elevation of serum IRE tends to occur at earlier stages of pancreatic cancer. No one test is adequate for the accurate diagnosis of pancreatic cancer. However, the two assays complement each other, and their combined use would provide a sensitive clue for tentative diagnosis of pancreatic cancer.

Adenocarcinoma↗
PubMed1988

Complementary DNA cloning of cytochrome P-450s related to P-450(M-1) from the complementary DNA library of female rat livers. Predicted primary structures for P-450f, PB-1, and PB-1-related protein with a bizarre replacement block and their mode of transcriptional expression.

Three kinds of cDNA clones were isolated from a cDNA library synthesized from female rat liver mRNA by cross-hybridization with the P-450(M-1) cDNA as a probe and sequenced. One clone appears to be the previously isolated P-450f cDNA clone with an additional 5'-untranslated and coding sequence which are lacking in the previously reported clone (Gonzalez, F. J., Kimura, S., Song, B.-J., Pastewka, J., Gelboin, H. V., and Hardwick, J. P. (1986) J. Biol. Chem. 261, 10667-10672), though several nucleotide differences were seen. Another one is for P-450PB-1 mRNA previously isolated, and the last has an almost identical nucleotide sequence to P-450PB-1 (the same report cited above) except for one region of 159 base pairs where the sequence homology between the two is abruptly broken down. This nonhomologous region appears to correspond exactly to the entire eighth exon, estimated by comparison with the gene structure of the related P-450 (P-450(M-1)). This replacement in P-450PB-1 (ps) causes a frameshift in the open reading frame, resulting in the generation of a truncated form of P-450 with a strange replacement block and lacking the heme-binding region. This observation suggests that the mRNA whose cDNA was cloned here was produced from a recombinant gene generated by gene conversion or from alternative splicing of a cryptic exon. Sex- and age-dependent expression of the mRNAs investigated by dot blot analysis revealed that normal- and pseudo-type PB-1 mRNA were expressed in both male and female rat livers, though their age-dependent expression was different in male and female animals. In addition, both the mRNAs were specifically expressed in the female brain of 8 weeks, whereas practically no expression was observed in kidney and lung of both sexes.

Amino Acid Sequence↗
PubMed1988

Dynamic changes in Sertoli cell processes invading spermatid cytoplasm during mouse spermiogenesis.

Studies using thick sections stained by ATPase cytochemistry and scanning electron microscopy were carried out to determine three-dimensional ultrastructural alterations in Sertoli cell processes invading neighboring spermatids during mouse spermiogenesis. Sertoli cell processes start invading spermatid cytoplasm at the acrosomal phase of development and undergo considerable change at the maturation phase of development. At step 14, these processes elongate and begin to branch in the spermatid cytoplasm, and by step 15, they extend in various directions to form a complex of canals that the authors have designated the canal complex. The present observations also clarify that the complicated canal complex undergoes regional modification. At the late stages of maturation, the endoplasmic reticulum has gathered with other cell organelles to form aggregates of endoplasmic reticulum in the vicinity of which invading Sertoli cell processes extensively ramify further into thin tubules that intertwine with each other to form a region of thin tubules. In thin sections, each such region was a complex, consisting of small vesicles and endoplasmic reticulum, and corresponded to what has been defined as a mixed body by Morales and Clermont (Anat. Rec., 203:233-244, 1982). During the course of the formation of the region, the invading Sertoli cell processes are continuous at all times with the cell body of the surrounding Sertoli cell.

Adenosine Triphosphatases↗
PubMed1988

Regulation of protein synthesis by polyamines.

Present experimental data show that the synthesis of ribosomal protein S1 and PI protein was stimulated greatly by polyamines at the early stage after addition of putrescine in polyamine-requiring mutants of E. coli. No macromolecular synthesis was stimulated at this stage. Polyamine stimulation of the synthesis of these proteins probably plays an important role for cell growth. In polyamine-deficient bovine lymphocytes, protein synthesis became perturbed before RNA and DNA synthesis. Among enzymes concerned with DNA replication, thymidine kinase activity was most strongly influenced by polyamines. The activity in polyamine-deficient cells was only 7% of the level in normal cells. Judging from the amount of thymidine kinase mRNA and its distribution in polysomes, it was concluded that polyamines mainly regulate the synthesis of thymidine kinase at the level of initiation of protein synthesis. A polyamine-free protein synthetic system, established from components of rabbit reticulocytes, consisted of globin mRNA, salt-washed ribosomes, partially purified initiation factors, and pH 5 enzymes. Spermidine added to this system not only lowered the optimal magnesium concentration required for globin synthesis, but it also stimulated the globin synthesis 8- to 10-fold. The optimal spermidine concentration was 0.4 to 0.6 mM, a concentration similar to that in intact rabbit reticulocytes. The ratio of alpha to beta globin chains synthesized in the presence of spermidine and Mg2+ was approximately 1.0, while the ratio in the presence of only Mg2+ was approximately 1.5. The results strongly suggest that polyamines play an important role in rabbit reticulocyte protein synthesis.

Animals↗
PubMed1988

Gastric hamartomatous polyp without polyposis coli: radiologic diagnosis.

Gastric hamartomatous polyps were found in 25 patients over a period of 4 1/2 years, for an incidence of 11% in all endoscopically biopsied polyps. The number of polyps was fewer than 5 in most patients. All polyps were sessile, sharply demarcated, hemispheric protrusions, measuring up to 10 mm in diameter but most were less than 5 mm. The most characteristic finding differing from hyperplastic polyps, adenoma, and polypoid carcinoma was that hamartomatous polyps were located in the fundic gland mucosa, which was demonstrated as a rugal area on moderately distended double-contrast radiographs.

Adult↗
PubMed1988

Inhibition of in vitro fertilization by a monoclonal antibody reacting with the zona pellucida of the oviductal egg but not with that of the ovarian egg of the golden hamster.

A glycoprotein designated ZP-0 is secreted from the epithelial cells of the oviduct and is bound to the zonae pellucidae (ZPe) of the oviductal eggs. We have previously established a monoclonal antibody reacting with ZP-0, termed AZPO-8. In the present study, we have examined the effect of AZPO-8 on in vitro fertilization in the hamster. Treatment of the oviductal eggs with AZPO-8 at concentrations of more than 100 micrograms/ml resulted in: (1) the formation of "zona precipitation" on the outer region of the ZP; (2) inhibition of sperm binding to ZP; (3) the acquisition of resistance to protease treatment. Fertilization was inhibited by AZPO-8 in a dose-dependent manner. These results indicate that a monoclonal antibody (MoAb) to an additional component of ZP derived from the oviduct shows an inhibitory effect on fertilization in vitro.

Animals↗
PubMed1988

Effects of medicinal plant extracts from Chinese herbal medicines on the mutagenic activity of benzo[a]pyrene.

The effects of medicinal plants on the mutagenicity of benzo[a]pyrene were studied with Salmonella typhimurium tester strains. The chosen medicinal plants are very frequently used as Chinese herbal medicines. Each medicinal plant was extracted with hot water, which is similar to the method used in Chinese medicinal treatment. Cinnamomi cortex, Rhei rhizoma, Scutellariae radix and Rehmanniae radix were found to decrease the mutagenic activity of benzo[a]pyrene. Atractylodis rhizoma also reduced the mutagenicity of benzo[a]pyrene, but this was not certain, because it showed a killing effect on the cell survival test. Bupleuri radix and Aurantii nobilis pericarpium had an enhancing effect, but then neither of these extracts is itself mutagenic. Each medicinal plant extract showed a different effect on the mutagenicity of benzo[a]pyrene. These effects were classified into 5 types: (I) decreasing effect, (II) killing effect, (III) enhancing effect, (IV) enhancing and decreasing effect and (V) inactive.

Benzo(a)pyrene↗