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S Nakai

Publications and source records attributed to S Nakai.

At least 253 records · Page 14Linked to original sources
PubMed1982

Long terminal repeat-like elements flank a human immunoglobulin epsilon pseudogene that lacks introns.

There are at least three immunoglobulin epsilon genes (C epsilon 1, C epsilon 2, and C epsilon 3) in the human genome. The nucleotide sequences of the expressed epsilon gene (C epsilon 1) and one (C epsilon 3) of the two epsilon pseudogenes were compared. The results show that the C epsilon 3 gene lacks the three intervening sequences entirely and has a 31-base A-rich sequence 16 bases 3' to the putative poly(A) addition signal, indicating that the C epsilon 3 gene is a processed gene. The C epsilon 3 gene sequence is homologous to the five separate DNA segments of the C epsilon 1 gene; namely, a segment in the 5'-flanking region (100 bases) and four exons, which are interrupted by a spacer region or intervening sequences. Long terminal repeat (LTR)-like sequences which contain TATAAA and AATAAA sequences as well as terminal inverted repeats are present in both 5'- and 3'-flanking regions. The 5' and 3' LTR-like sequences do not, however, constitute a direct repeat, unlike transposable elements of eukaryotes and retroviruses. The 3' LTR-like sequence is repetitive in the human genome, but is not homologous to the Alu family DNA. Models for the evolutionary origin of the processed gene flanked by the LTR-like sequences are discussed. The C epsilon 3 gene has a new open frame which codes potentially for an unknown protein of 292 amino acid residues.

Amino Acid Sequence↗
PubMed1982

Evaluation of radiation-induced chromosomal aberrations in human peripheral blood lymphocytes in vitro: result of an IAEA-coordinated programme.

The results of an IAEA coordinated programme on radiation induced chromosomal aberrations in human peripheral blood lymphocytes in vitro are presented. In a master experiment, a whole blood sample from one donor was irradiated with 200 R of X-rays. Different fixation times from 46 to 82 h were used. The progression of cells into mitosis was monitored by BrdUrd incorporation. 14 investigators took part in the scoring of chromosomal aberrations. The main conclusions of this study are: (1) The mean frequencies of aberrations changed with fixation time. (2) The number of cells scored as aberrant by different laboratories was very similar, but there was variability in the number of aberrations scored per aberrant cell. (3) The differences in the frequencies of aberrations between laboratories were minimal when the scoring was restricted to the first major peak of mitotic activity and sufficient cells were scored. It is concluded that using controlled experimentals conditions, human peripheral blood lymphocytes can effectively be used as a reliable biological dosimeter for absorbed radiation dose.

Argentina↗
PubMed1982

Radiation-induced chromosome aberrations in lymphocytes from man and crab-eating monkey. The dose-response relationships at low doses.

To obtain information on the relation between yield of chromosome aberrations and dose at low-dose levels, experiments were conducted with 5, 10, 20, 30 and 50 rad of 137Cs gamma-rays, on lymphocytes from man and crab-eating monkey (Macaca fascicularis). The dose-response relationship for dicentrics was obtained from the combined data of these low-dose experiments with those of our previous ones at high doses (100-400 rad). When the difference between observed yields and those expected from the linear-quadratic model were computed, the dose-response curve had a good fit for man, but not for the monkey. The linear regression lines between 0 and 30 rad were calculated, because the expected values of alpha/beta for man and monkey would be about 100 and 60 rad. The human data gave a satisfactory fit to a linear model, i.e., a linear increase in aberration frequency with dose, whereas this was not so for those of the monkey. Furthermore, there was some suggestive evidence for the existence of a plateau in dicentric yields between 10 and 30 rad for the monkey and between 20 and 30 rad for human lymphocytes, but more data would be needed to verify this suggestion, particularly for human lymphocytes.

Animals↗
PubMed1982

Structure of human immunoglobulin gamma genes: implications for evolution of a gene family.

We have cloned five human immunoglobulin gamma genes from a fetal liver gene library. Four of them encode the known human immunoglobulin gamma chains gamma 1, gamma 2, gamma 3 and gamma 4. A fifth gamma gene seems to be a pseudogene. Nucleotide sequence determination demonstrates that the gamma 3 gene contains four separate hinge exons. Comparison of these hinge exons with those of the other gamma genes indicates that the first hinge exon is homologous to that of the pseudogene, and that the other three hinge exons are homologous to that of the gamma 1 gene, suggesting that the gamma 3 gene ancestor is a hybrid gene created by unequal crossing-over between the ancestral gamma 1 and psi gamma genes. Amplification of the gamma 1-type hinge exon probably followed to complete the gamma 3 gene. This hypothesis inevitably postulates the gene order 5'-gamma 1-gamma 3-psi gamma-3'. Cloning of overlapping chromosomal segments demonstrates that the gamma 2 gene is located 19 kb 5' to the gamma 4 gene. These analyses indicate that the human gamma-gene family has evolved by several types of DNA rearrangemet, including duplication of a complete gene; duplication of a hinge exon; and reassortment of exons by unequal cross-over between two adjacent genes.

Animals↗
PubMed1982

Percutaneous embolisation of major spinal cord artery as a treatment for intractable spasticity.

Based on the angiographic findings of the injured spinal cord percutaneous embolisation of Adamkiewicz's artery was carried out to control intractable spasticity in ten cases of late stage spinal cord paralysis. The purpose of this procedure was to interrupt the reflex arcs of the lower extremities by decreasing the blood supply to the lumbar enlargement. Results were excellent in two cases, good in five and poor in three. Major effects were found in adduction and flexion spasticity of the hip joints and bladder function was always preserved in these patients. It is speculated that occlusion of Adamkiewicz's artery mainly affected the lower thoracic and the upper lumbar segments. Anastomosis between the anterior spinal artery and the two posterior spinal arteries might have provided sufficient collateral blood circulation to the conus level. It is emphasised that the percutaneous embolisation of Adamkiewicz's artery reduced the intractable spasticity of the lower extremities without changes in the voiding function of the automatic bladder.

Adult↗
PubMed1982

Nucleotide sequences of gene segments encoding membrane domains of immunoglobulin gamma chains.

The nucleotide sequences of the exons encoding membrane-bound IgG1, IgG2a, and IgG2b of mouse were determined and compared with the sequence of membrane-bound IgM. The sequences indicate that membrane-bound gamma chains bear an additional 71 residues at the COOH termini, including 17-residue acidic, 26-residue hydrophobic, and 28 residue hydrophilic portions. The hydrophobic portion, which seems to be anchored in the lipid bilayer of the membrane, is highly conserved among membrane-bound mu and gamma chains. We propose the presence of a membrane protein that recognizes the conserved hydrophobic segment and anchors the membrane-bound immunoglobulin. Comparison of the nucleotide sequences revealed another example of intervening sequence-mediated domain exchange around one of the membrane exons.

Amino Acid Sequence↗
PubMed1982

[Pharmacological properties of buprenorphine, a new analgesic agent. Part II. (author's transl)].

Pharmacological properties of buprenorphine were compared with those of morphine and pentazocine. Buprenorphine scarcely showed any effects on spontaneous EEGs and sleep-wakefulness cycles. Buprenorphine tended to depress the recruiting and augmenting responses and the spindle burst, and it also inhibited the hypothalamic arousal response. Buprenorphine had weaker emetic action than morphine and protected against apomorphine-induced emesis in the same manner as morphine. Buprenorphine scarcely affected respirations, blood pressure, heart rate, blood flow, ECG, cardiac contractile force, cornary flow, and intracranial pressure. However, morphine and pentazocine caused depressed respiration, decreased blood pressure, increased blood flow and cardiac contractile force, and elevated intracranial pressure. Buprenorphine, morphine, and pentazocine did not affect bile secretion, but produced contraction of the sphincter of Oddi. Buprenorphine had very little effect on renal function, but morphine and pentazocine reduced this function to depress urine flow. Buprenorphine and morphine inhibited carrageenin-induced edema. Buprenorphine had no effect on blood histamine level, but morphine increased the concentration of histamine. These results indicate that buprenorphine has little effect on the central nervous system, respiratory and cardiovascular system, and renal function.

Analgesics, Opioid↗
PubMed1982

[Interactions between buprenorphine, narcotic analgesic, and centrally acting drugs in prolongation of halothane-induced sleeping and analgesia (author's transl)].

Interactions between buprenorphine, narcotic analgesic, and centrally acting drugs were studied in prolongation of halothane-induced sleeping and analgesia using the D'Amour-Smith method in mice, and the effect of buprenorphine on monoamine metabolism was studied in rat brain. Diazepam and chlorpromazine prolonged the halothane-induced sleeping time dose-dependently. Buprenorphine (0.01, 0.1, and 1 mg/kg s.c.) inhibited the effect of diazepam, but not that of chlorpromazine. Pentazocine and naloxone also inhibited the effect of diazepam, but morphine did not. It is suggested that the inhibitory effect of buprenorphine on prolongation of halothane-induced sleeping time by diazepam is due to its opiate antagonistic property. Since narcotic antagonists inhibited the effect of diazepam, the endogenous opiate system seems to be involved in this effect. Diazepam or droperidol had no effect on the analgesia of buprenorphine, morphine, and pentazocine. Buprenorphine analgesia was inhibited by reserpine and p-chlorophenylalanine, potentiated by 5-hydroxytryptophan, and not affected by alpha-methyl-p-tyrosine or 3,4-dihydroxyphenylalanine. These results suggest that the serotonergic system plays a modulating role in buprenorphine analgesia. Imipramine and nialamide inhibited buprenorphine analgesia in the test at low stimulus intensity, but potentiated at high stimulus intensity. Buprenorphine (0.1, 1 and 10 mg/kg s.c.) increased the dopamine metabolites, 3,4-dihydroxyphenylacetic acid and homovanillic acid, in various brain areas and the serotonin metabolite, 5-hydroxyindoleacetic acid, in midbrain.

Analgesia↗
PubMed1981

Cloning of mouse immunoglobulin epsilon gene and its location within the heavy chain gene cluster.

Mouse immunoglobulin epsilon chain gene was cloned from DNA of a hybridoma producing anti-dinitrophenyl IgE, which was constructed by fusing a spleen cell of a BALB/c mouse with a variant clone of MOPC21 myeloma (IgG1 producer). Because a given active heavy chain constant region (CH) gene is linked to a heavy chain joining segment (JH) gene at its 5' side, the expressed C epsilon gene of the hybridoma was cloned from a phage library containing partial Sau3A digests of IgE hybridoma DNA by using a J gene fragment as a probe. Among 6 X 10(5) phages screened, five positive clones were obtained and three of them were identified as C epsilon gene clones by restriction mapping, Southern blot hybridization, R-loop formation, and partial nucleotide sequence determination. The determined nucleotide sequence predicted the amino acid sequence which resembles a part of the CH3 domain of human epsilon chain. The deletion profile of the C epsilon gene in various myelomas expressing different CH genes indicates that the C epsilon gene is located between the C gamma 2a and C alpha genes. The linkage (5'-epsilon-alpha-3') was directly confirmed by molecular cloning of the overlapping chromosomal segments from newborn mouse DNA.

Animals↗
PubMed1981

Structure of a rearranged gamma 1 chain gene and its implication to immunoglobulin class-switch mechanism.

An expressed gene for gamma 1 chain of MC 101 myeloma was cloned from a phage library containing partial EcoRI digests of MC 101 DNA. The cloned DNA was analyzed by restriction enzyme cleavage, Southern blot hybridization, R-loop formation, and nucleotide sequence determination. The results indicate that the expressed gamma 1 chain gene comprises at least four germline DNA segments, namely a variable-region gene, a segment of the 5' flanking region of the mu chain gene (containing J regions), a segment of the 5' flanking region of the alpha chain gene, and the gamma 1 chain gene with its flanking regions. The presence of the alpha chain gene-flanking switch (S) region (S alpha region) at the 5' side of the gamma 1 chain gene-flanking region (S gamma 1 region) indicates that the heavy chain class switch may not be mediated by stepwise linear deletion along the order of the heavy chain constant-region genes (5'-mu-gamma 3-gamma 1-gamma 2b-gamma 2a-alpha-3'). We propose a siter-chromatid exchange model that explains class switch-associated deletion of heavy chain genes by unequal crossing-over events between sister chromatids.

Base Sequence↗
PubMed1981

Rearrangements of immunoglobulin genes during differentiation and evolution.

Immunoglobulin genes are shown to undergo dynamic rearrangements during differentiation as well as evolution. We have demonstrated that a complete immunoglobulin heavy chain gene is formed by at least two types of DNA rearrangement during B cell differentiation. The first type of rearrangement is V-D-J recombination to complete a variable region sequence and the second type is S-S recombination to switch a constant region sequence. Both types of recombination are accompanied by deletion of the intervening DNA segment. Structure and organization of CH genes are elucidated by molecular cloning and nucleotide sequence determination. Organization of H chain genes is summarized as VH-(unknown distance)-JH-(6.5 kb)-C mu-(4.5 kb)-C delta-(unknown distance)-C gamma 3-(34 kb)-C gamma 1-(21 kb)-C gamma 2b-(15 kb)-C gamma 2a-(14.5 kb)-C epsilon-(12.5 kb)-C alpha. The S-S recombination takes place at the S region which is located at the 5' side of each CH gene. Nucleotide sequence of the S region comprises tandem repetition of closely related sequences. The S-S recombination seems to be mediated by short common sequences shared among S regions. A sister chromatid exchange model was proposed as a mechanism for S-S recombination. Comparison of nucleotide sequences of CH genes indicates that immunoglobulin genes have scrambled by intervening sequence-mediated domain transfer during their evolution.

Animals↗
PubMed1980

Cloning of human immunoglobulin mu gene and comparison with mouse mu gene.

We have cloned a 12 kb DNA segment containing human mu gene and its flanking sequence from human fetal liver DNA library using mouse mu gene as a probe. Partial nucleotide sequence determination shows that the cloned DNA contains the sequence encoding human mu chain. This is the first constant region gene of the human heavy chain that is cloned. We have compared human and mouse mu genes by heteroduplex analysis and Southern blot hybridization. The results clearly show that not only the sequence encoding the CH4 domain but also the 5'-flanking (S mu) sequence is conserved between human and mouse mu genes, suggesting that the nucleotide sequence in the S mu region has an important biological function, presumably a recognition signal for the class switch recombinant as proposed previously.

Animals↗
PubMed1980

Hydrophobicity determined by a fluorescence probe method and its correlation with surface properties of proteins.

The fluorescence method of Sklar et al. (Sklar, L.A., Hudson, B.S. and Simoni, R.D. (1977) Biochemistry 16, 5100-5108) using cis-parinaric acid as a probe was applied to determine the effective hydrophobicity of proteins. The initial slope (S0) of fluorescence intensity vs. protein concentration plot was used as an index of the protein hydrophobicity. A good correlation was observed for S0 of native proteins, denatured proteins and surfactant-bound proteins with an effective hydrophobicity determined by the hydrophobic partition method. The effective hydrophobicity determined fluorometrically showed significant correlations with interfacial tension and emulsifying activity of the proteins studied. The fluorescence technique using cis-parinaric acid is useful for determination of the effective hydrophobicity, as the procedure is much simpler and quicker than hydrophobic chromatography and hydrophobic partition.

Animals↗