PubMed Health⌕ Search

Biomedical subjects

M Kumagai

Publications and source records attributed to M Kumagai.

At least 19 recordsLinked to original sources
PubMed1997

Prevalence and growth characteristics of malignant stem cells in B-lineage acute lymphoblastic leukemia.

We used a stroma-supported culture method to study the prevalence and growth characteristics of malignant stem cells in acute lymphoblastic leukemia (ALL). In 51 of 108 B-lineage ALL samples, bone marrow-derived stroma not only inhibited apoptosis of ALL cells but also supported their proliferation in serum-free medium. When single leukemic cells were placed in the stroma-coated wells of microtiter plates, the percentage of wells with leukemic cell growth after 2 to 5 months of culture ranged from 6% to 20% (median, 15%; 5 experiments). The immunophenotypes and genetic features of cells recovered from these cultures were identical to those noted before culture. All cells maintained their stroma dependency and self-renewal capacity. Leukemic clones derived from single cells contained approximately 10(3) to 10(6) cells after 1 month of culture; other clones became detectable only after prolonged culture. Cell growth in stroma-coated wells correlated with the number of initially seeded cells (1 or 10; r = .87). However, the observed percentages of positive wells seeded with 10 cells always exceeded values predicted from results with single-cell-initiated cultures (P < .003 by paired t-test), suggesting stimulation of leukemic cell growth by paracrine factors. In conclusion, the proportion of ALL cells with clonogenic potential may be considerably higher than previously thought.

Adipose Tissue↗
PubMed1997

3,5,3'-Triiodo-L-thyronine potentiates all-trans-retinoic acid-induced apoptosis during differentiation of the promyeloleukemic cell HL-60.

Although the programmed cell death mediated by thyroid hormone is not well evaluated in mammalian cells, thyroid hormone plays a crucial role in differentiation of the cells during the metamorphosis of Xenopus, suggesting that thyroid hormone has the potential ability to induce the apoptosis. To investigate the thyroid hormone-inducible apoptosis, we cultured HL-60 cells with various amounts of all-transretinoic acid (RA) and L-T3. T3 alone did not induce the apoptosis of the cells. T3, however, suppressed the proliferation of cells in the presence of RA. DNA ladder and microscopical examination showed that the reduction of cell number was due to the apoptosis induced by RA. These findings suggested that T3 affects the apoptotic process during the differentiation of HL-60 cells by RA. T3-inducible apoptosis may require the factors augmented by RA in HL-60 cells.

Apoptosis↗
PubMed1997

Reduction of challenge parasite population in gerbils, Meriones unguiculatus, chronically infected with Schistosoma mansoni.

Homologous challenge parasite attrition in gerbils, Meriones unguiculatus, chronically infected with Schistosoma mansoni, was investigated by the recovery technique of retrograde portal perfusion. Whereas the animals vaccinated with gamma- or UV-attenuated cercariae of S. mansoni showed a marginal level of resistance, the chronically infected gerbils exhibited significant parasite attrition against a homologous challenge infection. Our data do not corroborate a previous report suggesting a lack of resistance in gerbils with chronic S. mansoni infection. The gerbil represents an additional experimental host for evaluating acquired resistance to S. mansoni, including that induced by previous exposure to irradiated larvae on chronic infection.

Animals↗
PubMed1997

[Organ preservation in the treatment of malignant solid tumors in children].

Organ preservation is one of the requirements for maintaining the high quality of life after the treatment of malignant solid tumors in children. We analyze our recent results of renal preservation in the abdominal neuroblastoma and describe 3 cases of successful organ preservation in pelvic malignancy. Between 1982 and 1996, 29 patients with adrenal or retroperitoneal neuroblastoma, that extended into the surrounding tissues and organs and/or to the contralateral side, underwent delayed primary excision. Before 1982, 9 patients were treated and only one ipsilateral kidney was preserved. On the other hand, 13 of 20 kidneys were preserved after 1987. Adoption of cis-platinum deepened our awareness of preserving the kidney. Furthermore, we have altered our strategy since 1987 to continuing preoperative chemotherapy until the size of the tumor becomes as small as it is estimated completely resectable by our own index, which is derived from computed tomography. Kidneys are shielded during intraoperative irradiation, and the tumor relapsed from the shielded area of retroperitoneum in one patient. Four of 14 preserved kidneys became atrophic and lost their function. The bladder and the rectum were left intact at tumor resection after intensive chemotherapy in two patients with pelvic (one retroperitoneal and one vaginal) rhabdomyosarcoma. A yolk sac tumor of the vagina responded completely to chemotherapy with cis-platinum, etoposide and bleomycin. The patient has survived 7.5 years without any local and distant relapse in spite of the fact that surgery, aside from several diagnostic biopsies, was not undertaken.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1996

Stroma-supported culture in childhood B-lineage acute lymphoblastic leukemia cells predicts treatment outcome.

We developed a stroma cell culture system that suppresses apoptosis of malignant cells from cases of B-lineage acute lymphoblastic leukemia. By multiparameter flow cytometric measurements of cell recovery after culture on stromal layers, we assessed the growth potential of 70 cases of newly diagnosed B-lineage acute lymphoblastic leukemia and related the findings of treatment outcome in a single program of chemotherapy. The numbers of leukemic cells recovered after 7 d of culture ranged from < 1 to 292% (median, 91%). The basis of poor cell recoveries from stromal layers appeared to be a propensity of the lymphoblasts to undergo apoptosis. The probability of event-free survival at 4 yr of follow-up was 50 +/- 9% (SE) among patients with higher cell recoveries ( > 91%), and 94 +/- 6% among those with reduced cell recoveries (+/- 91%; P = 0.0003). The prognostic value of leukemic cell recovery after culture exceeded estimates for all other recognized high-risk features and remained the most significant after adjustment with all competing covariates. Thus, the survival ability of leukemic cells on bone marrow-derived stromal layers reflects aggressiveness of the disease and is a powerful, independent predictor of treatment outcome in children with B-lineage acute lymphoblastic leukemia.

Analysis of Variance↗
PubMed1996

CD38 signal transduction in human B cell precursors. Rapid induction of tyrosine phosphorylation, activation of syk tyrosine kinase, and phosphorylation of phospholipase C-gamma and phosphatidylinositol 3-kinase.

Ligation of CD38 inhibits proliferation and induces apoptosis of human immature B cells, but the molecular mechanisms underlying this function are unknown. We found that CD38 dimerization with the specific mAbs T16 and IB4 induces rapid and transient tyrosine phosphorylation of several intracellular proteins in the immature B cell lines RS4;11, REH, 380, Nalm6, and OP-1. This effect could be markedly reduced by incubating cells with the tyrosine kinase inhibitors genistein, staurosporine, and herbimycin A. CD38 dimerization induced tyrosine phosphorylation of the protein kinase syk and increased syk kinase activity. CD38 dimerization also induced tyrosine phosphorylation of phospholipase C-gamma and of the p85 subunit of phosphatidylinositol 3-kinase (PI 3-K). The latter was accompanied by a distinct increase in PI 3-kinase activity in the immunoprecipitates obtained with an anti-phosphotyrosine Ab. In contrast to the signaling triggered by surface Ig engagement in B lymphocytes, CD38 ligation did not appear to induce tyrosine phosphorylation of the src-like protein tyrosine kinases lyn, fyn, and btk, or of vav- and ras-GTPase-activating protein, nor did it induce detectable changes in cytosolic CA2+ concentrations. CD38 signaling also differed from cytokine-induced signaling in that it did not cause tyrosine phosphorylation of Jak1 and Jak2. Finally, CD38 ligation did not inhibit IL-3-induced tyrosine phosphorylation of Jak2. These results identify CD38 as a cell surface receptor with signal transduction properties activated by dimerization. Induction of signal transduction by CD38 ligation implies the existence of a yet unidentified natural ligand of CD38.

ADP-ribosyl Cyclase↗
PubMed1996

Confirmation of a "safety zone" by intraoperative cholangiography during laparoscopic cholecystectomy.

BACKGROUND: Creating a "safety zone" during laparoscopic cholecystectomy is defined as dissection of the cystic duct as close as possible to the gallbladder. METHODS: In 29 out of 802 cases in which laparoscopic cholecystectomy was difficult to perform due to uncertainty about the orientation of Calot's triangle, intraoperative cholangiography was performed, using a titanium clip as a marker that designated the safety zone. The distance between the clip and the common hepatic duct or the common bile duct could be determined by evaluation of two intraoperative cholangiograms taken in different orientation. RESULTS: If the clip was located in the safety zone, and was distant from the common hepatic duct or common bile duct, the safety of preparation around the clip was ensured. No complication was encountered in these cases with this method. Eventually, no biliary tract injury was experienced, and the overall conversion rate to open cholecystectomy was only 0.4% (3 of 802 consecutive cases). CONCLUSIONS: This method of confirming the safety zone by intraoperative cholangiography is a useful procedure for avoiding inadvertent injury to the biliary tract.

Bile Duct Diseases↗
PubMed1996

Laparoscopic transcystic cholangioscopic lithotripsy for common bile duct stones during laparoscopic cholecystectomy.

BACKGROUND AND STUDY AIMS: Following the recent introduction of laparoscopic cholecystectomy (LC) for cholecystolithiasis, treatment of concomitant common bile duct (CBD) stones has been evaluated by using laparoscopic choledochotomy, a transcystic approach, or by means of endoscopic sphincterotomy (ES) before or after LC. PATIENTS AND METHODS: During laparoscopic cholecystectomy, we attempted lithotripsy of CBD stones using laparoscopic transcystic cholangioscopy with lithotripsy (LTCL), in 70 patients out of 950 laparoscopic cholecystectomies. Preparatory tests included laboratory values, ultrasound, and performance of endoscopic retrograde cholangiography (ERC) with placement of a nasobillary tube (without sphincterotomy). RESULTS: Introduction of the cholangioscope into the CBD was successful in 65 patients (92.9%) and CBD clearance was completely achieved by LTCL alone in 51 (78.5%). The overall success rate was therefore 73%. The remaining 19 cases required postoperative procedures such as extracorporeal shock-wave lithotripsy without ERC or ES (successful in all). The average hospital stay period was 9.4 days for patients in whom CBD clearance was achieved by LTCL alone. This period did not differ significantly from that of patients who underwent LC alone (8.4) days. The operation time was about 70 minutes longer for the LTCL group (total time 174 minutes on average) than for the LC group (107 minutes). We did not observe any series complications during or after LTCL (mean follow-up period: 34 months). CONCLUSION: LTCL in combination with LC allows shortening of the hospital stay and a swift return to work for patients with CBD stones. This procedure also preserves the function of the sphincter of Oddi, so that the longterm prognosis for patients is likely to be very good.

Adult↗
PubMed1996

[Effect of macrolides on cytokine mRNA expression in human whole blood model].

Recently, low dose and long term use of Macrolides (Mls) has been reported to be effective in treatment of chronic lower respiratory tract infections, however its mechanism is still obscure. We evaluated the effect of Mls (EM, AZM, RKM) on cytokine mRNA expressions. We preincubated the whole blood with several concentrations of Mls and removed the Mls and then stimulated human whole blood with LPS as an experimental vivo model. In order to examine cytokine mRNA expressions, we used the RT-PCR method. Cytokine mRNA expressions were suppressed significantly (p < 0.05) by pretreatment with EM, AZM; moreover, the suppression was peaked at low concentrations (0.04 approximately 0.2 microgram/ml). Although, Cytokine mRNA expressions were not suppressed by pretreatment with RKM. These results suggest that EM, AZM have suppression on Cytokine mRNA expressions, and consequently, this suppression has a reasonable effect for DPB patients.

Anti-Bacterial Agents↗
PubMed1996

[Detection of human cytomegalovirus-antigen in peripheral blood cells by using flow-cytometer].

Prophlaxis of CMV-associated disease and/or early initiation of therapy is important in the management of patients with CMV infection. Recently, we developed the CMV antigenemia assay: a rapid and quantitative method based on the detection of CMC antigens in peripheral blood leukocytes by flow cytometry. Heparinized peripheral blood was obtained from healthy donors, bone marrow transplantation patients, patient with collagen disease and patients with adult T cell leukemia. To determine the phenotype of HCMV-infected mononuclear cells, the following phycoerythrin-conjugated mAb were used: CD8, CD15. These mAds were added to the whole blood and incubated. After the hemolysis, the cells were fixed with 4% paraformaldehyde and 0.3% NP-40. To determine the HCMV-infected cells, the following mAb were used in flow cytometry analysis: E13 (Chemicon Inc., Toyo) against HCMV IEA. As a secondary antibody, a FITC-conjugated goat anti-mouse IgG. In the bone marrow transplant patients, CMV-associated antigen was positive in their monocytes and polymorphocytes. In the patient with collagen disease, CMV-antigen was positive in their lymphocytes and monocytes. Our study demonstrates that the detection of CMV antigen-positive blood leukocytes by FACScan is a rapid and quantitative method and useful for the diagnosis and monitoring of CMV-associated CMV-associated disease. The CMV blood antigen assay by FACScan will facilitate the initiation of early treatment with ganciclovir of CMV-associated disease or the administration of prophylactic ganciclovir for preventing the disease.

Adult↗
PubMed1996

Human B-cell progenitors and bone marrow microenvironment.

Apoptosis of normal and leukemic immature B-cells in vitro is suppressed by contact with bone marrow-derived stromal layers. In stroma-supported cultures of immature B-cells, we found that ligation of CD38, a type II transmembrane protein, inhibited the cell growth and induced apoptosis. CD38 ligation also induced tyrosine phosphorylation and activation of intracellular substrates, including syk, phospholipase C-gamma, c-cbl, and phosphatidylinositol 3-kinase (PI 3-K). Wortmannin and LY294002, two potent inhibitors of PI 3K, rescued immature B cells from CD38-mediated growth suppression. In vitro culture of leukemic lymphoblasts may have potentially important clinical application. First, stroma-supported cultures of acute lymphoblastic leukemia (ALL) cells can determine the growth potential of leukemic cells. In a series of 70 children enrolled in a single program of chemotherapy, cell growth on stroma was a powerful and independent prognostic indicator. Second, a culture system capable of maintaining the majority of ALL blast cells at high levels of viability is also ideally suited for testing antileukemic drugs. Promising results were obtained with 2-chloro-deoxyadenosine and interleukin-4, leading to clinical trials of these two compounds in children with refractory ALL. In addition, we compared the direct antileukemic activities of dexamethasone and prednisolone and found that dexamethasone is five to six times more cytotoxic (on a molar basis) than prednisolone, in agreement with the anti-inflammatory activities of these drugs. This finding may serve to guide the selection of dexamethasone dosage in the treatment of ALL.

ADP-ribosyl Cyclase↗
PubMed1995

Deglycosylation of antiherpesviral 5-substituted arabinosyluracil derivatives by rat liver extract and enterobacteria cells.

A number of antiherpesviral 5-substituted derivatives of 1-beta-D-arabinofuranosyluracil (araU) were significantly resistant to phosphorolysis by rat liver extract (S-9), but were gradually deglycosylated in a 2% enterobacteria cell suspension. The relative order of the resistance conferred by the different C-5 substituents was: 5-propynyl > 5-(E)-2-bromovinyl > 5-(E)-2-chlorovinyl > 5-methyl > 5-iodo. The 2'-fluoro derivatives of araU were completely resistant to phosphorolysis by both liver extract and enterobacteria, whereas the corresponding ribofuranosyl and 2'-deoxyribofuranosyl nucleosides were easily phosphorolysed by S-9, and were immediately cleaved in a 1% enterobacteria cell suspension. These findings suggest that antiherpesviral 5-substituted araU analogues can be relatively stable in vivo, when injected intravenously, and that degradation of 1-beta-D-arabinofuranosyl-5-(E-2-bromovinyl)uracil (sorivudine) following oral administration is due primarily to the action of enterobacteria.

Animals↗
PubMed1995

Ligation of CD38 suppresses human B lymphopoiesis.

CD38 is a transmembrane glycoprotein expressed in many cell types, including lymphoid progenitors and activated lymphocytes. High levels of CD38 expression on immature lymphoid cells suggest its role in the regulation of cell growth and differentiation, but there is no evidence demonstrating a functional activity of CD38 on these cells. We used stroma-supported cultures of B cell progenitors and anti-CD38 monoclonal antibodies (T16 and IB4) to study CD38 function. In cultures of normal bone marrow CD19+ cells (n = 5), addition of anti-CD38 markedly reduced the number of cells recovered after 7 d. Cell loss was greatest among CD19+ sIg- B cell progenitors (mean cell recovery +/- SD = 7.2 +/- 11.7% of recovery in control cultures) and extended to CD19+CD34+ B cells (the most immature subset; 7.6 +/- 2.2%). In contrast, CD38 ligation did not substantially affect cell numbers in cultures of normal peripheral blood or tonsillar B cells. In stroma-supported cultures of 22 B-lineage acute lymphoblastic leukemia cases, anti-CD38 suppressed recovery of CD19+ sIg- leukemic cells. CD38 ligation also suppressed the growth of immature lymphoid cell lines cultured on stroma and, in some cases, in the presence of stroma-derived cytokines (interleukin [IL] 7, IL-3, and/or stem cell factor), but did not inhibit growth in stroma- or cytokine-free cultures. DNA content and DNA fragmentation studies showed that CD38 ligation of stroma-supported cells resulted in both inhibition of DNA synthesis and induction of apoptosis. It is known that CD38 catalyzes nicotinamide adenine dinucleotide (NAD+) hydrolysis into cyclic ADP-ribose (cADPR) and ADPR. However, no changes in NAD+ hydrolysis or cADPR and ADPR production after CD38 ligation were found by high-performance liquid chromatography; addition of NAD+, ADPR, or cADPR to cultures of lymphoid progenitors did not offset the inhibitory effects of anti-CD38. Thus, anti-CD38 does not suppress B lymphopoiesis by altering the enzymatic function of the molecule. In conclusion, these data show that CD38 ligation inhibits the growth of immature B lymphoid cells in the bone marrow microenvironment, and suggest that CD38 interaction with a putative ligand represents a novel regulatory mechanism of B lymphopoiesis.

ADP-ribosyl Cyclase↗
PubMed1995

Lower-extremity venous stasis during laparoscopic cholecystectomy as assessed using color Doppler ultrasound.

Lower-extremity venous stasis during laparoscopic cholecystectomy was evaluated in 16 patients by monitoring the blood velocity in the femoral vein and the femoral vein size (cross-sectional area) using color Doppler ultrasonography. The blood velocity in the femoral vein decreased significantly after the start of 10-mmHg abdominal insufflation in the supine position. When the patients were placed in a reverse Trendelenburg position during 10-mmHg insufflation, blood velocity in the femoral vein further decreased. However, velocity returned to the baseline after deflation. The cross-sectional area of the femoral vein was significantly elevated after the start of 10 mm Hg insufflation in the supine position. When patients were placed in the reverse Trendelenburg position during 10-mmHg insufflation, this parameter was further elevated, but returned to the baseline soon after deflation. These results indicate that femoral vein stasis during laparoscopic cholecystectomy can be minimized by reducing the pressure of abdominal insufflation and avoiding elevation of the patient's head as much as possible.

Blood Flow Velocity↗
PubMed1995

A novel assay for illegitimate recombination in Escherichia coli: stimulation of lambda bio transducing phage formation by ultra-violet light and its independence from RecA function.

We developed a novel assay system for illegitimate recombination, in which the frequency of the formation of lambda Spi- phages formed during prophage induction was measured with an E. coli P2 lysogen as the indicator bacteria. Since almost all of the lambda Spi- phages thus detected contain attR, they have essentially the same structures as lambda bio transducing phages, indicating that this assay system enables us to detect specialized transducing phages that produce heterogenote transductants, thus ignoring the occurrences of docL and docR particles which carry only one cohesive end. The following results on the formation of specialized transducing phages have been obtained by this assay system to date. (1) Irradiation with UV light greatly enhanced the formation of lambda Spi- phages. (2) Treatments with other DNA-damaging agents also enhanced the formation of lambda Spi- phages. (3) Illegitimate recombination during prophage induction does not require the RecA function, indicating that enhancement of lambda Spi- phage formation is not controlled by the SOS regulatory system. (4) Preliminary results suggested that DNA gyrase is involved in the formation of lambda Spi- phage during pro-phage induction. Since the above results were consistent with most of the previous observations on the illegitimate recombination in other systems, the Spi- assay system can provide important clues to the mechanism of illegitimate recombination.

Attachment Sites, Microbiological↗
PubMed1995

Femoral vein stasis during laparoscopic cholecystectomy: effects of graded elastic compression leg bandages in preventing thrombus formation.

Venous stasis of the legs during laparoscopic cholecystectomy was compared between patients without graded compression leg bandages (Group 1; n = 12) and patients with such bandages (Group 2; n = 12) by measuring mean blood flow velocity and cross-sectional area of the femoral vein using a color Doppler ultrasonography. In Group 1, when velocity and area were measured in the supine position, a significant decrease in velocity (p < .05) and a significant increase in area (p < .05) occurred after abdominal insufflation to 10 mm Hg. These changes were greater during abdominal insufflation in the reverse Trendelenburg position than during abdominal insufflation in the supine position. In Group 2, flow velocity was significantly higher (p < .05) before abdominal insufflation as compared with Group 1. After abdominal insufflation to 10 mm Hg and a postural change, velocity significantly decreased (p < .05) and area significantly increased (p < .05) in Group 2, similar to the results in Group 1. During abdominal insufflation at 5 mm Hg or lower, the use of the graded compression bandage was found to be useful for preventing femoral vein stasis. During abdominal insufflation at 10 mm Hg or in the reverse Trendelenburg position, the bandage did not prevent femoral vein stasis.

Bandages↗
PubMed1995

Assignment of the tenascin gene (HXB) to swine chromosome 1q21.1-->q21.3 by fluorescence in situ hybridization.

The chromosomal location of the swine tenascin gene (HXB) was determined by fluorescence in situ hybridization and simultaneous R-banding. Swine tenascin cDNA was labeled with biotin, and used as a probe. Hybridization was detected by the FITC-labeled streptavidin/biotinylated antistreptavidin antibody system. The signals revealed that the tenascin gene is localized on swine chromosome 1q21.1-->q21.3.

Animals↗