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Biomedical subjects

M Ohkubo

Publications and source records attributed to M Ohkubo.

At least 127 records · Page 7Linked to original sources
PubMed1986

Enhanced expression of a 37,000-dalton protein in human lung cancers.

When proteins in the tissue extracts of lung cancers were analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (PAGE), a 37,000-dalton protein (37K) was detected as a prominent form in all cases thus far examined. This protein was barely detectable or its amount was very small in the normal lung tissue extracts. Two-dimensional PAGE of lung tumor extracts showed 37K as a major spot with an isoelectric point of 7.6. An antibody against 37K was raised in a rabbit by injecting purified 37K. Immunoblot analysis of normal lung and lung tumor tissues revealed that the affinity-purified anti-37K antibody specifically recognized 37K and that the intensities of immunostaining corresponded to those of Coomassie brilliant blue staining.

Electrophoresis, Polyacrylamide Gel↗
PubMed1986

Similarity between glyceraldehyde-3-phosphate dehydrogenase and a 37,000-dalton protein which is abundantly expressed in human lung cancers.

Human lung cancers of all histological types contain a protein of 37,000 daltons (37K) as an abundant component. Partial sequence analysis of purified 37K revealed a strong homology with glyceraldehyde-3-phosphate dehydrogenase (GAPDH, EC 1.2.1.12). Tryptic peptide mapping analysis showed that the pattern of 37K was very similar to those of GAPDHs both purified from lung tumor and obtained commercially. An antibody raised against 37K in a rabbit also reacted with authentic GAPDH. These results suggest a possible involvement of GAPDH itself or a GAPDH-related protein in lung tumorigenesis.

Amino Acid Sequence↗
PubMed1985

Salt induced conformational transition between A and Z forms of r(CGCGCG) as revealed by a Raman spectroscopic study.

Solution conformation in different conditions of r(CGCGCG) has been studied by a Raman spectroscopic method. In NaCl solution, r (CGCGCG) takes only an A-form duplex in which guanosine and cytidine have C3'endo-anti conformation even at 5M salt concentration. In much higher ionic strength condition (5M NaCl plus 1M MgCl2 or 6M NaClO4), it undergoes a transition to a left-handed Z-form. The Raman spectrum of the Z-form RNA was found to be very similar to that of Z-form DNA, suggesting that Z-RNA involves a C3'endo-syn guanosine and an in between form of C2'endo-Cl'exo-anti cytidine.

Kinetics↗
PubMed1984

Synthesis and conformational studies of ribooligonucleotides which contain an alternating C-G sequence and show unusual circular dichroism spectra.

The poly [r(C-G)] duplex shows an unusually large negative CD band in the long wavelength region. In order to elucidate this phenomenon, r(C-G-C-G) and r(C-G-C-G-C-G) were synthesized by a phosphotriester method and their properties were examined by UV, CD, 1H and 31P NMR spectroscopy. These ribooligomers form self-duplexes at low temperature, the CD spectra of which show negative bands at around 290 nm and positive bands at around 265 nm. The results of 1H nuclear Overhauser effect experiments, 1H chemical shift-temperature profiles of base protons, and the sharp singlet observed for all H1' protons are consistent with a normal A-RNA structure but not with a Z-DNA like structure. The CD-temperature profiles and 31P NMR spectra support this conclusion. These results indicate that RNA duplexes with an alternating C-G sequence can give an unusually large negative CD band in the long wavelength region despite their right-handed helical structure.

Base Sequence↗
PubMed1984

Gastrin-releasing peptide immunoreactivity in medullary thyroid carcinoma.

Two cases of gastrin releasing peptide (GRP)-producing medullary thyroid carcinoma are presented. Immunohistochemical examination revealed the presence of GRP-like immunoreactivity (IR-GRP) in the primary tumor tissues. High concentration of IR-GRP was also demonstrated in extracts of the primary tumors by radioimmunologic means with use of a GRP-specific antiserum. Chromatographic analysis showed that the immunoreactivity was composed of at least two molecular forms: one behaved as synthetic porcine GRP on Sephadex G-50 gel filtration and the other as porcine GRP (14-27), a C-terminal active fragment of GRP. The IR-GRP was shown not to be attributed to bombesin-like immunoreactivity. Substance P-like immunoreactivity was not detected in the tumor tissues by either immunohistochemical or radioimmunologic means. This is, as far as the authors are aware, the first finding of IR-GRP as an ectopic product in medullary carcinoma.

Calcitonin↗
PubMed1984

Conformation of ribooligonucleotide duplexes containing an alternating C-G sequence which show an unusual circular dichroism spectrum.

The poly[r(G-C)] duplex shows an unusually large negative band in the long wavelength region of the CD spectrum. In order to elucidate this phenomenon, r(C-G-C-G) and r(C-G-C-G-C-G) were synthesized chemically and their properties were examined by UV and CD, and 1H and 31P NMR spectroscopy. These ribooligomers form a self-complementary duplex at low temperature, the CD spectrum of which shows a negative band at around 290 nm and a positive band at around 265 nm with almost equal magnitudes. The proton resonances in the 1H NMR spectra of the oligo[r(C-G)] duplexes were assigned by nuclear Overhauser effect experiments. The chemical shift-temperature profiles of the base proton signals and the sharp singlets observed for all H1' protons are consistent with a normal A-RNA structure but not with a Z-DNA like structure. Moreover, a 500-MHz two-dimensional nuclear Overhauser effect experiment recorded for r(C-G-C-G-C-G) shows that all guanine bases adopt the normal anti-conformation. CD-temperature profiles and 31P NMR spectra of oligo[r(C-G)]s support this conclusion. These results indicate that duplexes of oligo- and polyribonucleotides containing alternating C-G sequences can give an unusually large negative CD band in the long wavelength region despite their right-handed helical structure.

Base Sequence↗
PubMed1983

Purification and characterization of N1-methylnicotinamide oxidases I and II separated from rat liver.

N1-Methylnicotinamide (1-CH3Nmd) oxidases I and II of the livers of Wistar strain male rats were separated by DEAE-cellulose column chromatography and purified by AcA 34 gel filtration, Affi-Gel blue column chromatography, and sucrose density gradient centrifugation. These two enzymes were purified 568- and 82-fold with yields of 1.4 and 0.1% of the total activity in the liver homogenate, respectively. They showed the same molecular weight of 300,000 by AcA 34 gel filtration and a single protein band with a molecular weight of 150,000 in sodium dodecyl sulfate-polyacrylamide disc gel electrophoresis. The difference in antigenicities of these two enzymes was observed with double immunodiffusion and immunoprecipitation using antibody produced in rabbits against each enzyme. Furthermore, these two enzymes were found to be different from each other in the heat stability, optimum pH values, Km values for 1-CH3Nmd, and response to various inhibitors.

Aldehyde Oxidase↗
PubMed1983

Increase of nicotinamide methyltransferase and N1-methyl-nicotinamide oxidase activities in the livers of the rats administered alkylating agents.

Twenty four hours after intraperitoneal injection of alkylating agents, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), N-methyl-N-nitrosourea (MNU) and methyl methanesulfonate (MMS), into rats, an increase in nicotinamide (Nmd) methyltransferase and N1-methylnicotinamide (1-CH3Nmd) oxidase activities in the liver was found. Since activities of these enzymes in the liver extracts were not stimulated directly by these agents in vitro, it is postulated that the increases in these enzyme activities are due to the induction of each enzyme.

Aldehyde Oxidase↗
PubMed1979

Serum 25-hydroxy-vitamin D in hepatobiliary disease in infancy.

Serum 25-hydroxy-vitamin D (25-OHD) concentrations were measured in 49 patients with hepatobiliary disease in infancy. Low mean values were found in groups of patients with biliary atresia, neonatal hepatitis, choledochal cyst, and chronic intrahepatic cholestatic syndrome. In the group of patients with surgically repaired biliary atresia, the mean value did not differ from normal. Parenteral vitamin D increased 25-OHD in serum in patients with biliary atresia, but did not do so in one patient with neonatal hepatitis. In contrast, oral vitamin D did not increase serum 25-OHD concentrations in patients with biliary atresia. It is concluded that the reduction of serum 25-OHD seen in biliary atresia was largely due to the malabsorption of vitamin D, while in neonatal hepatitis it was due to impairment of 25-hydroxylation of the vitamin.

Bile Ducts↗
PubMed1977

A case of renal transplant recipient complicated with cryptococcosis and amphotericin B induced acute tubular necrosis.

An adult renal transplant recipient was complicated with cryptococcal lung granuloma and meningitis. Treatment with the antifungal agents, 5-fluorocytocin and clotrimazole had to be discontinued due to side effects. Whereas, the intrathecal administration of amphotericin B proved effective for meningitis but intravenously it induced acute tubular necrosis to the transplanted kidney. In order to cure the persistant fungal lung granulomas in renal transplant patients early surgical excision seems to be essential.

Acute Kidney Injury↗