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Biomedical subjects

S Fujimori

Publications and source records attributed to S Fujimori.

At least 73 records · Page 4Linked to original sources
PubMed1991

Disturbance in the metabolism of 5'-methylthioadenosine and adenine in patients with neoplastic diseases, and in those with a deficiency in adenine phosphoribosyltransferase.

5'-Methylthioadenosine (MTA) produced during the synthesis of polyamines is degraded to adenine by MTA phosphorylase. This pathway is considered to be the main source of endogenous adenine. We determined the concentrations of MTA and adenine in control subjects and in those with a pathological disorder. In patients with active leukemias, as well as with other types of malignancies, the concentrations of MTA and adenine in the urine were elevated. These changes seemed to be the result of an accelerated production of MTA due to an accelerated biosynthesis of polyamine. In patients with adenine phosphoribosyltransferase (APRT) deficiency, the concentrations of adenine in the urine were elevated, presumably due to a disturbance in the catabolism of adenine. Although adenine is a potent inhibitor of MTA phosphorylase, APRT-deficient patients did not excrete MTA into urine in concentrations significantly larger than noted for control subjects. However, the amount of MTA excreted positively correlated with that of adenine in these patients, hence that accumulated adenine probably had a slight, but positive, inhibitory effect on the degradation of MTA.

Adenine↗
PubMed1991

[Construction of an arithmetic ability scale for grades three through five].

To construct a scale for arithmetic ability, three forms of test were built and administered to grades three through five. Applying the two-parameter item response model, all parameters of the model were estimated simultaneously for three test forms. Thus, it was possible to compare the difficulty and the discriminating power of all items in a common scale. Accuracy of ability estimation of each test, which was evaluated by the test information function, revealed that precision of estimation was enough for practical use. In the common scale, the average of estimated ability was--.35 for grade three, 0.0 for grade four, and 1.48 for grade five, showing that the difference between grade three and four was small, compared to that between grade four and five. Possible applications of the scale were also discussed.

Aptitude Tests↗
PubMed1991

Enantio- and meso-oligodeoxyribonucleotides.

As sugar-modified oligodeoxyribonucleotides, L-homooligomers (L-dA12 and L-dT12) and a L/D-alternative oligomer ((L-dA-D-dA)6) were synthesized. These oligomers were quite resistant towards phosphodiesterase degradations. L-dA12 formed complexes with poly(dT) and poly(U) at 0 degree C with different stabilities, on the other hand L-dT12 did not show obvious hypochromicities after mixing with complementary natural homopolymers. An alternative sequence, (L-dA-D-dA)6, interacted with both type homopolymers and stabilities of the complexes increased compared to that of L-dA12.

Oligodeoxyribonucleotides↗
PubMed1991

[HPRT deficiency].

Explore the source record for details and available documents.

Base Sequence↗
PubMed1990

Measurement of 5'-methylthioadenosine in patients with neoplasms.

The amount of polyamines in urine from patients with various neoplasms is larger than in normal subjects. We have determined the concentration of 5'-methylthioadenosine (MTA), a by-product of the polyamine biosynthesis, in patients with malignancies as well as normal subjects. Our studies indicate that the amount of MTA in urine from patients with leukemias and malignant lymphomas was higher than in normal subjects (p less than 0.005). Urine samples from patients with other malignancies contained normal amounts of MTA. The levels of blood MTA in patients with leukemias before treatment or in relapse was higher than in control subjects (p less than 0.005), while in patients with other malignancies and leukemia in remission, the levels were not different from control subjects. Peripheral blood MTA levels clearly decreased after effective chemotherapy. The measurement of MTA levels in urine and blood may not be as useful as polyamine assays for the detection of malignancies, but blood levels of MTA may be useful as an indicator of the efficacy of chemotherapy in leukemic patients.

Adenosine↗
PubMed1990

Hypoxanthine guanine phosphoribosyltransferase deficiency: nucleotide substitution causing Lesch-Nyhan syndrome identified for the first time among Japanese.

A previously undescribed nucleotide substitution at codon 51 (CGA to TGA) has been identified using the polymerase chain reaction technique in hypoxanthine guanine phosphoribosyltransferase (HPRT) cDNA; this is the first molecular evidence for a point mutation in a Japanese patient with Lesch-Nyhan syndrome. The present mutation is the 19th nucleotide substitution identified as a germ-line mutation at this locus and the second mutation generating a stop codon. The position of the nucleotide substitution is exactly the same as a previously described mutation HPRTToronto, indicating for the first time that nucleotide substitutions at the same position in the sequence of HPRT can generate different mutant alleles, one causing a partial deficiency and the other a complete deficiency. Although the type of nucleotide substitution is different between the two cases, a single base position has twice become the target of a mutation. However, the calculation of the probability of finding substitution mutations at the same base position in the coding region of hprt indicates that there is no evidence for the presence of a hot spot for substitution mutations in the human hprt germ line.

Adolescent↗
PubMed1990

Enantio-oligodeoxyribonucleotides.

As a sugar-modified oligonucleotide, a hexamer of 9-(2-deoxy-beta-L-erythro-pentafuranosyl)-9H-purin-6-amine, [L-(dAp)5dA], was synthesized by triester method. The L-hexamer was resistant to bovine spleen phosphodiesterase. UV absorption studies indicated that L-hexamer formed a complex with poly U but not with poly dT at 0 degrees C. It was assumed that enantio-DNA's possese the ability to distinguish complementary RNA from DNA.

Adenine Nucleotides↗
PubMed1990

Differential expression of gamma-aminobutyric acidA receptor subunits.

A 1.8-kilobase (kb) cDNA clone for a beta 1 subunit of the human gamma-aminobutyric acidA (GABAA) receptor has been isolated and sequenced. The longest open reading frame of the clone, pCLL610, contains nucleotide sequence encoding a portion of the putative signal sequence followed by 449 amino acids of the entire mature protein. The deduced amino acid sequence of pCLL610 differs from a recently described human beta 1 subunit by a single amino acid. The amino acid sequences of the human GABAA receptor beta 1 subunits share 98% identity with the beta 1 subunits of the bovine and rat GABAA receptor, with the majority of the differences occurring in the intracellular loop between the M3 and M4 transmembrane regions of the protein. A single 11-kb transcript is observed in Northern blots of poly(A)+ RNA isolated from rat brain probed with nick-translated pCLL610. In human brain, the pCLL610 probe recognized the 11-kb message, in addition to two other bands between 8 and 11-kb. Developmental studies of rat brain mRNA show that the message of the GABAA beta 1 subunit is highest at birth, rapidly decreases, and reaches adult levels of 5 to 7 days of age. This is in contrast to the development of the alpha 1 subunit, which is low from days 1 to 5 and increases to adult levels by days 14 to 25. Relative levels of the mRNA for the alpha 1 and beta 1 subunits vary among rat brain regions. The levels of mRNA for the alpha 1 subunit are similar in the cortex, hippocampus, and midbrain, whereas cerebellar levels are twice those in the cortex. The rank order of the relative amount of beta 1 subunit message is hippocampus greater than cortex = midbrain greater than cerebellum. These data, taken with our previous study of the alpha 1 subunits of the GABAA receptor, suggest that the differences in the distribution and regulation of the alpha 1 and beta 1 subunits may reflect a variety of subunit combinations forming the GABAA receptor. Heterogeneity in the GABAA receptor composition may provide a molecular basis for the diverse pharmacological properties associated with this receptor.

Aging↗
PubMed1989

Lesch-Nyhan syndrome due to a single nucleotide change in the hypoxanthine-guanine phosphoribosyltransferase gene (HPRTYale).

We have cloned and sequenced a full length cDNA for HPRT cDNA for HPRTYale isolated from Lesch-Nyhan subject and identified a single nucleotide substitution which results in amino acid substitution of glycine to arginine. Since most HPRT mutants have normal levels of specific HPRT messenger RNA, mutant cDNA analysis is the method of choice to define the mutation in HPRT deficient subjects.

Amino Acid Sequence↗
PubMed1989

Identification of a single nucleotide change in the hypoxanthine-guanine phosphoribosyltransferase gene (HPRTYale) responsible for Lesch-Nyhan syndrome.

Complete deficiency of hypoxanthine-guanine phosphoribosyltransferase (HPRT) causes the Lesch-Nyhan syndrome. Previous characterization of a mutant form of HPRT, HPRTYale, from a subject with the Lesch-Nyhan syndrome revealed normal mRNA and protein concentrations, no residual catalytic activity, and cathodal migration upon PAGE. We have cloned and sequenced HPRTYale cDNA. The nucleotide sequence of full-length HPRTYale cDNA revealed a single nucleotide substitution compared with normal HPRT cDNA: G----C at nucleotide position 211. This transversion predicts substitution of arginine for glycine at amino acid position 71, explaining the cathodal migration of HPRTYale. Chou-Fasman secondary structure analysis predicts a change in the probability of beta-turn formation in the region containing the mutation. Inclusion of the bulky arginine side chain in place of glycine probably disrupts protein folding as well. Cloning mutant forms of cDNA allows identification of specific mutations, provides insight into mutational mechanisms, and facilitates structure-function analysis of mutant proteins.

DNA↗
PubMed1989

[Pulmonary complications subsequent to fractured neck of the femur in the elderly].

Fracture of the neck of the femur (FNF) is a common disorder in the elderly. A total of 618 cases consisting of 117 males and 501 females, whose age was 65 years or more, were enrolled in a prospective study. A total of 45 cases among them revealed pulmonary complications. These were divided into the following three groups: Group 1 (4.7%) who had respiratory disease(s) or symptoms prior to the fracture; Group 2 (1.9%), diagnosed as having pulmonary thromboembolism (PTE). In Group 3 (0.6%), PTE was a possible diagnosis but it was not distinguished from pneumonia in precise. In the patients of group 2 and 3, respectively, the following respiratory symptoms were observed: dyspnea (31.3%), productive cough (25%), syncope (12.6%), chest pain (6.3%), tachycardia (46.7%), and tachypnea (50%). An abnormal chest roentgenogram was found 56.4% in both group 2 and 3. Seven patients in group 2 showed remarkable reduction of PaO2 on admission, however these all recovered within 7 days without any thrombolytic treatment. The prevalence of PTE caused by FNF in the elderly was close to that in younger cases, but the clinical symptoms were less in the former.

Aged↗