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Biomedical subjects

A Kudo

Publications and source records attributed to A Kudo.

At least 19 recordsLinked to original sources
PubMed1992

A critical role of lambda 5 protein in B cell development.

The lambda 5 gene is a homolog of immunoglobulin J lambda-C lambda genes, expressed specifically in immature B-lineage cells. Lambda 5-encoded molecules form membrane complexes with mu or D mu proteins in association with an additional protein specifically expressed in immature B cells that is encoded by the Vpre-B gene. We have generated mice in which the lambda 5 gene is inactivated by targeted gene disruption in embryonic stem cells. In these mice, B cell development in the bone marrow is blocked at the pre-B cell stage. However, the blockade is leaky, allowing B cells to populate the peripheral immune system at a low rate. These cells are allelically excluded and able to respond to antigen.

Animals↗
PubMed1992

Pre-B lymphocyte-specific transcriptional control of the mouse VpreB gene.

The VpreB genes, which encode surrogate immunoglobulin light chain molecules, are expressed as RNA almost exclusively in pre-B cells. We have investigated the transcriptional control mechanisms which are responsible for the pre-B cell-specific RNA expression of the mouse VpreB1 and VpreB2 genes. Nuclear run-on analyses demonstrate that the pre-B cell-specific expression of both VpreB genes is controlled primarily at the level of initiation of transcription. S1 nuclease protection-mapping defined two or three major start sites of transcription for the VpreB genes. To find a promoter and other potential cis-acting regulatory elements, a 700-bp fragment 5' of the transcription start sites of the VpreB1 gene was used in gene transfer experiments and found to act as a promoter in pre-B lymphocytes. Deletion experiments showed that 191 bp upstream of the most 5' transcription start site is required for the pre-B cell promoter activity. DNA sequence analysis of the 5' region of the mouse VpreB1, VpreB2 and human VpreB genes reveal that this region of approximately 200 bp is strongly conserved. This 200-bp promoter region contains several conserved nucleotide sequence motifs which may act to mediate the pre-B cell-specific transcription of the VpreB genes.

Animals↗
PubMed1992

A pre-B- and B cell-specific DNA-binding protein, EBB-1, which binds to the promoter of the VpreB1 gene.

The VpreB1 protein is thought to be expressed on the surface of pre-B cells in association with lambda 5 and mu heavy chain, and to play an important role on B cell differentiation. The expression of VpreB1 and lambda 5 is pre-B cell specific, and regulated at the initiation of transcription. We have identified at least two sequence-specific DNA-binding proteins which bind to the region -191 to -74 of the promoter of the mouse VpreB1 gene. These DNA-binding proteins also bind to the promoter of the mouse lambda 5 gene. One of the two DNA-binding proteins, called EBB-1, is restricted to pre-B and B cells, but not detected in plasma cells, T cells and cells of other lineages. Transient transfection analysis of reporter constructs revealed that the binding sites of these proteins play a significant role in the activity of the promoter, especially the binding site of EBB-1. Taken together these results suggest that EBB-1 might be one of the crucial factors which regulates a series of intracellular events in B cell differentiation.

Animals↗
PubMed1992

Time-dependent changes of collagen cross-links and their precursors in the culture of osteogenic cells.

The early stage of cross-link formation in bone collagen was studied in a cell culture system. An osteogenic cell line that produces and accumulates a remarkably high amount of collagen, and that eventually forms bone-like structures, was used in this study for its time-dependent development of reducible cross-links. It was found that precursors of the cross-link, dehydro-dihydroxynorleucine and dehydro-hydroxynorleucine became detectable as soon as the cells attained a confluent state. They showed maximal amounts at days 3-5 after confluence, but substantially disappeared at day 10 after confluence. In contrast, two characteristic cross-links of bone collagen, dehydro-dihydroxylysinorleucine (dehydro-DHLNL) and dehydro-hydroxylysinorleucine (dehydro-HLNL), which were present in trace amounts at the stage of cell confluence, gradually increased in amount and reached a plateau at day 10, just when their precursors disappeared. Thus, it was found that there was a time lag of about a week between the maximal formations of precursors and cross-links of bone collagen in this system. The significance of this time lag was interpreted in terms of the minimum essential accumulation of collagen for the precursor-product transition. The ratio of dehydro-DHLNL to dehydro-HLNL was as low as 0.7 at day 3 after confluency, increased to 4.2 at day 20, the period just before mineralization began, and decreased thereafter, suggesting a qualitative change in bone collagen associated with mineralization.

Animals↗
PubMed1992

The expression of the mouse VpreB/lambda 5 locus in transformed cell lines and tumors of the B lineage differentiation pathway.

The expression of RNA transcripts from two pre B lymphocyte related genes, VpreB and lambda 5, has been studied in a series of transformed cell lines which appear frozen at different states of B lineage differentiation, from early progenitors to surface Ig positive B cells. In the HAFTL-1 cell line, which arose from fetal liver by transformation with a retrovirus containing the Hras oncogene, Northern analysis of poly A+ mRNA as well as in situ hybridization of RNA in single cells revealed that lambda 5 and VpreB are already expressed at the progenitor stage and increase in expression as the progenitors differentiate to precursor (preB) cells, or are turned off as the progenitors differentiate to myeloid cells. Continued rearrangements of Ig genes in pre B cell lines leading to Ig expression on the surface of NFS-5 pre B cells do not influence the continued expression of VpreB and lambda 5. Surface Ig-positive B lineage cell lines also express the pre B-related genes. Both Ly1+ as well as Ly1- pre B cells are VpreB- and lambda 5-positive. Lipopolysaccharide (LPS) stimulation of 70Z/3 pre B cells does not turn off lambda 5 expression. It therefore appears that, at least in transformed cell lines, the expression of VpreB and lambda 5 is not directly regulated by the expression of microH, kappa L, or lambda L chains, LPS reactivity, or the Ly1 surface antigen. Fusion of plasmacytoma cells with normal pre B cells to generate pre B hybridomas leads to down-regulation of VpreB/lambda 5 expression.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1992

[Clinical study on total intravenous anesthesia with droperidol, fentanyl and ketamine. 14. Effect on epidural pressure].

We studied effect of total intravenous anesthesia using ketamine, fentanyl and droperidol (DFK) on epidural pressure as an index for cerebrospinal fluid pressure in six surgical patients who underwent gastrectomy. The epidural catheter was inserted on the previous day. The epidural puncture was made at Th7-12 and the tip of the catheter was located 5 cm cephalad. The epidural pressure was measured before, just after and 30 minutes after the induction. The induction dose of fentanyl was 5 micrograms.kg-1 and that of ketamine was 1 mg.kg-1. The epidural pressure at the induction decreased in significantly by 19% as compared with that before the induction. The result suggested that DFK would not increase cerebrospinal fluid pressure when the doses of ketamine and fentanyl were changed.

Adult↗
PubMed1991

Long-term proliferating early pre B cell lines and clones with the potential to develop to surface Ig-positive, mitogen reactive B cells in vitro and in vivo.

Cell lines and clones were established from PB76-positive mouse fetal liver at day 13 and 14 of gestation, which proliferated with division times of a day in serum-substituted cultures under the stimulatory influence of adherent stromal cells and the cytokine IL-7 for periods longer than half a year. These lines expressed varying levels of the B lymphocyte lineage related markers PB76, B220, BP-1, VpreB and lambda 5, but no surface Ig or MHC class II molecules. All clones expressed PB76, VpreB and lambda 5 in a high percentage of cells, while B220 and/or BP-1 expression was low or undetectable in some. A cell line, and several clones established from it, all had kappa and lambda light chain genes in germ-line configuration. Either one or both of their H-chain-gene containing chromosomes carried a DH to JH. These pre B cell lines and clones could be induced to VH to DH and VL to JL rearrangements. This resulted in the development of varying percentages of sIg-positive surface, MHC class II negative, LPS-reactive B cells within 2-3 days, in the absence of contacts with stromal cells and/or IL-7. When injected into SCID mice, the cultured pre B cells populated the spleen of these mice to 5% with surface Ig-, MHC class II-positive LPS-reactive cells for greater than 25 weeks. The long-term in vitro proliferative capacity of these DH-JH rearranged pre B cell clones makes them major candidates for committed stem cells of the B lineage.

Animals↗
PubMed1991

Potassium ion channels operated by receptor stimulation can be activated simply by raising temperature.

Application of either dopamine (DA), acetylcholine (ACh), or histamine (HA) to the identified ganglion cells of Aplysia elicits a K(+)-dependent slow hyperpolarization. When temperature of the bathing solution was raised from 22 to 32 degrees C, these cells were also hyperpolarized with a marked increase in K+ conductance. The warm- and transmitter-induced current responses recorded under voltage clamp were not blocked by either 1 mM Ba2+ or 10 mM TEA. Intracellularly injected guanosine 5'-O-(2-thiodiphosphate) (GDP beta S) depressed both warm- and transmitter-induced K+ responses immediately after the injection. Intracellular application of guanosine 5'-O-(3-thiotriphosphate) (GTP gamma S) caused a gradual, irreversible increase in K+ conductance of the plasma membrane and occluded both responses. Transmitter-induced response markedly decreased when the temperature was raised from 22 to 32 degrees C, suggesting that the response to transmitter was occluded during the warm-induced response. These results suggested that the G-protein regulating the receptor-operated K+ channels could be activated simply by raising temperature.

Acetylcholine↗
PubMed1991

A slow voltage-dependent Na(+)-current induced by 5-hydroxytryptamine and the G-protein-coupled activation mechanism in the ganglion cells of Aplysia.

Application of 5-hydroxytryptamine (5HT) induces a slowly depolarizing response in the neurons of Aplysia abdominal ganglion. In voltage-clamped cells, 5HT induced a slow inward current that increased steeply with membrane depolarization from -85 mV showing a negative slope conductance, but never reversed into outward when hyperpolarized beyond the equilibrium potential for K+. The 5HT-induced response was markedly augmented in Ca(2+)-free media, but depressed in Na(+)-free media, and unaffected by a change in external potassium. Intracellular injection of guanosine 5'-O-(2-thiodiphosphate) (GDP beta S) significantly depressed the 5HT response in a dose-dependent way. Injection of cholera toxin (CTX) selectively blocked the 5HT-induced response, the effect being irreversible. Neither 3'-deoxyadenosine, an inhibitor of adenylate cyclase, nor H-8, an inhibitor of protein kinase A, depressed the 5HT response. 3-Isobutyl-1-methylxanthine (IBMX) did not augment the 5HT response appreciably. The 5HT responses were not depressed at all during a saturated response to Br-cyclic AMP injected intracellularly. It was concluded that the 5HT response is produced by opening of the voltage-dependent Na(+)-channels with activation of CTX-sensitive G-protein but not necessarily with an increase in intracellular cyclic AMP.

1-Methyl-3-isobutylxanthine↗
PubMed1991

[Clinical study on total intravenous anesthesia with droperidol, fentanyl and ketamine--11. Effect on epidural pressure].

We have developed a new method of total intravenous anesthesia using ketamine, fentanyl and droperidol (NLA-FK). There are many reports describing a significant increase in cerebrospinal fluid pressure (CSFP) during ketamine administration, but little is known about changes in CSFP during NLA-FK. As epidural pressure (EP) is considered as a good index for CSFP, we measured it in 12 patients under either NLA-FK or isoflurane anesthesia, who underwent gastrectomy. In the NLA-FK group the EP increased significantly by 26% at the induction of anesthesia as compared with the preinduction level, and it decreased to the preinduction level 30 minutes after the induction. Thereafter the pressure was not appreciably changed. In the isoflurane group EP significantly decreased by 16% at induction, but the pressure significantly increased by 29% 30 minutes after the induction as compared with the preinduction level. The change was similar to that of the NLA-FK group. Although the increase in the EP during the induction of NLA-FK is significant, it is considered to be within normal ranges. However, further detailed clinical study is needed to attenuate the significant increase in the EP during the induction of NLA-FK.

Anesthesia, Intravenous↗
PubMed1991

[Use of iontophoretic anesthesia for venipuncture].

The usefulness of iontophoretic anesthesia with 10% lidocaine was evaluated on insertion of venous catheters on 38 blood donors in a blood bank and on 41 patients in a hospital, after the arm was charged for 3, 6 or 9 minutes with 1.5 mA of electricity by using a hand-made iontophoretic anesthesia apparatus. In the blood donor group, the pain-relief effect was observed in 25% of donors after charging for 3 min; in 68% after 6 min; and in 93% after 9 min. In the patient group, anesthesia was observed in 14% of patients after 6 min and in 65% after 9 min though the effect was observed in 81% after 6 min and in 65% after 9 min. But only 45-48% of subjects in both groups requested the anesthesia after charging for either 6 or 9 min. This suggests that the duration for 9 min was not liked by the subject despite the pain on insertion. Therefore it is concluded that the charging duration of the iontophoresis must be shorter for this method to become useful as local anesthesia.

Adult↗
PubMed1990

The proteins encoded by the VpreB and lambda 5 pre-B cell-specific genes can associate with each other and with mu heavy chain.

The murine pre-B cell-specific genes VpreB and lambda 5, as well as the murine gene for mu heavy chain, were introduced into Ltk- fibroblast cells which normally do not express these genes. Stable transfectants carrying these genes produced the corresponding proteins of 15.5, 21.5, and 75 kD. They secreted the three proteins as a triple complex that could be immunoprecipitated by mu heavy chain-specific antibodies, consisting of one VpreB, one lambda 5, and one mu heavy chain. The mu heavy chain and lambda 5 were disulfide-bonded with each other, while the VpreB protein was noncovalently associated. These experiments proved that the VpreB, lambda 5 and mu H chain proteins can form a heavy/light chain-like heterocomplex.

Animals↗
PubMed1990

Selective IgG deficiency with a transcriptional disorder of the gamma switching region gene and the IL-4 gene.

A primary immunodeficiency patient was analysed whose serum IgG and IgE were extremely low but whose IgM and IgA levels were within the normal range or elevated. Southern blot analysis indicated no deletion of structural genes coding for C gamma, C epsilon, or C alpha. The majority of the patient's peripheral B cells expressed IgM and IgD on the surface yet IgG-positive B cells were not detected, suggesting that the defect is in a switch-recombination process from IgM to IgG. The RFLP pattern detected with the S mu and S gamma DNA regions revealed that there was no deletion or large mutation in the switch region DNA. An in vitro IgG production system with pokeweed mitogen showed an abnormality at the transcriptional level and the defects were in both the patient's T and B cells. Addition of recombinant IL-4 (rIL-4) to the normal B cells enhanced IgG production but the patient's B cells did not respond to rIL-4, although the IL-4 receptor was present at the normal level. Messenger RNA and IL-4 protein were not produced in the patient's T cells upon stimulation with phorbol ester and calcium ionophore, whereas IL-2 was normally produced. The patient's lymphocytes showed a proliferative response to various mitogens, including phorbol ester. The transcripts of unrearranged C gamma region genes were not detected in the patient's lymphocytes, suggesting that the chromatin structure of the S gamma region may not be open. These results suggest that the transcriptional defects at the S gamma region gene in B cells and at the IL-4 gene in the T cells may be responsible for the present IgG immunodeficiency. There might be a common transcriptional system operating in a certain step in the activation of both genes.

Adult↗
PubMed1990

Conversion of normal Ly-1-positive B-lineage cells into Ly-1-positive macrophages in long-term bone marrow cultures.

We obtained eight different cell lines in the long-term bone marrow culture system that showed a germ-line configuration of the joining (J) region segments of the Ig heavy-chain (IgH) genes. Their surface markers were CD45R+, Ly-1+, Lyb-2+, cIgM-, sIgM-, Ia-, Thy-1-, Mac-1-, and IL-2R (Tac)+. Use of very young mice and the presence of IL-5 were important for preferential promotion of the survival of B-lineage lymphocytes bearing the Ly-1 markers. When we treated two of them (J8 and J10) with 5-azacytidine for 24 h followed by co-culture with stromal cells and IL-5, they became Ly-1+, sIgM+ B cells, and Ly-1+, Mac-1+ macrophagelike cells, respectively. After other early lymphoid lines (J1, J8, and J13) were maintained by co-culture with ST2 and IL-5 for more than a year, they showed a heterogeneous DNA rearrangement profile of the J region segment of the IgH gene, although only J13 rearranged the kappa-light chain gene. Northern blot analysis revealed that these cell lines expressed C mu-mRNA, and lambda 5-mRNA, consistent with normal pre-B cells. Intriguingly, J1, J8, and J13 expressed c-fms mRNA constitutively. When J13 cells were co-cultured with ST2 and GM-CSF in place of ST2 and IL-5, they acquired Mac-1 expression and retained Ly-1 expression. They were morphologically macrophages, nonspecific-esterase-positive, and showed phagocytosis of latex beads. These results support evidence for a close relationship between the myeloid and Ly-1+ B-cell pathways of differentiation, and indicate that our IL-5-dependent clones are multipotential intermediates in differentiation from pro-B cells to B cells and macrophages.

Animals↗
PubMed1990

[Treatment of priapism with intracavernous injection of etilefrine hydrochloride].

A case of priapism following epidural anesthesia was reported. A 67 year old man received epidural anesthesia for the transurethral resection of a malignant bladder tumor. Epidural anesthesia which he had wanted to receive was given through the L3 to L4 intervertebral space with 18 ml of 2% lidocaine. The penile erection occurred while he was prepared and draped. Additional 8 ml of 1% lidocaine failed to overcome it and the operation cancelled. After this episode, he had anesthesia on 5 occasions in 2 years. General anesthesia was given 3 times without penile erection, but epidural block was tried on 2 occasions, which was followed by penile erection. For the penile erection, intracavernous injection of etilefrine hydrochloride was effective and surgical procedure could be done smoothly. The mechanism of priapism remained unclear but imbalance of the autonomic nervous system may be a involved. This case suggests that intracavernous injection of etilefrine hydrochloride is effective for treatment of penile erection during transurethral surgery.

Aged↗