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Biomedical subjects

M Kumagai

Publications and source records attributed to M Kumagai.

At least 19 recordsLinked to original sources
PubMed1998

CD3-CD4-CD8-CD56-CD19-CD14- cells and CD3+CD8 dull-positive cells produce IL-4 in AIDS patients.

We used flow cytometry to identify the presence of intracellular cytokines (cytoflow) and analyse the production of IL-4 in peripheral blood from AIDS patients who have practically no CD4+ T cells. We found that IL-4 was produced by CD3-CD4-CD8-CD56-CD19-CD14- cells and CD3+CD8 dull-positive cells in AIDS patients. Moreover, CD3-CD4-CD8-CD56-CD19-CD14- cells had helper activity for immunoglobulin synthesis. These findings indicate that instead of CD4+ T helper cells, C3-CD4-CD8-CD56-CD19-CD14- cells and CD3+CD8 dull-positive cells may be an important source of IL-4 in a variety of immune responses for AIDS patients.

Acquired Immunodeficiency Syndrome↗
PubMed1998

[Anesthetic management of parturients with intracranial hemorrhage accompanied by seizure].

Two preeclamptic parturients, who presented with generalized seizure, underwent emergency cesarean section without confirmed diagnosis. They developed focal neurological signs postoperatively, and were subsequently diagnosed as subarachnoid hemorrhage due to rupture of an intracranial aneurysm and possibly of arteriovenous malformation. Diagnosis should be made at the earliest possible time for the optimal anesthetic as well as postoperative management of the mother.

Anesthesia, General↗
PubMed1998

[HRCT findings of pulmonary Mycobacterium avium complex: a comparison with tuberculosis].

Computed tomographic (CT) findings of 70 patients with Mycobacterium avium complex (MAC) disease were analyzed by two chest radiologists and compared with those of 37 patients with Mycobacterium tuberculosis infection. Common CT findings in patients with MAC, included bronchiectasis (97%), small nodules (89%), parenchymal distortion (60%), bronchial wall thickening (56%), consolidation (50%) and cavity formation (49%) and small nodules (86%), bronchiectasis (70%), consolidation (57%) and bronchial wall thickening (51%) in patients with Mycobacterium tuberculosis. Bronchiectasis and parenchymal distortion were significant in patients with MAC compared with Mycobacterium tuberculosis patients. Bronchiectasis involving the RUL, RML, lingula and LLL and small nodules involving the RML were often seen in patients with MAC. Both bronchiectasis and small nodules were commonly observed in multiple lobes in both types of patients. Cavities in MAC infection tended to be thin and smooth walled, and less commonly associated with consolidation. We conclude that CT findings of MAC infection were characterized by widely distributed bronchiectasis and small nodules and/or cavities with thin, smooth walls. These CT findings are one of the keys in differentiating MAC from Mycobacterium tuberculosis.

Adolescent↗
PubMed1997

Differential and coordinated regulation of expression of norepinephrine transporter in catecholaminergic cells in culture.

The norepinephrine transporter (NET) terminates noradrenergic neurotransmission at synapse by high-affinity sodium-dependent reuptake into presynaptic terminals, and thus serves as a marker of differentiation of noradrenergic neurons. In the present study, we studied the regulatory mechanism of the expression of NET-mRNA in cultured neurons from newborn rat superior cervical ganglia (SCG) and in clonal rat pheochromocytoma cells (PC12) SCG neurons in culture expressed a high level of NET-mRNA, which was further increased 2.5-5 fold from day 1 to day 13. Treatment of SCG neurons with the cholinergic differentiation factor (CDF)/leukemia inhibitory factor (LIF) and ciliary neurotrophic factor (CNTF), neurokines known to induce the switch from adrenergic to cholinergic phenotype in SCG neurons, led to the suppression of the level of NET-mRNA in a concentration dependent manner, concomitantly with the suppression of mRNA for tyrosine hydroxylase (TH), an adrenergic marker enzyme in cultured SCG neurons. On the other hand, retinoic acid, a compound which is also known to increase the expression of choline acetyltransferase, a cholinergic marker enzyme, and suppress the expression of TH in the cultured SCG neurons and PCI2 cells, rather increased the level of NET-mRNA in these two cell populations. Alterations of the Na(+)-dependent norepinephrine transport activity which paralleled the changes in the NET-mRNA levels were confirmed by the [3H]norepinephrine uptake assay. These results indicate that cell extrinsic factors regulate the expressions of NET and TH genes by a common as well as by distinct mechanisms.

Amino Acid Sequence↗
PubMed1997

Characterization and CO2 Adsorptivity of Acid-Washed and Cation-Exchanged Natural Mordenites

A Japanese natural mordenite was modified by acid washing as well as cation-exchange. Crystal structure, porosity, and active sites of the modified natural mordenites were characterized, and their CO2 adsorptivity were examined. Contraction as well as expansion of the mordenitic unit cell in the natural zeolite and distortion of zeolite structure by acid washing are plausibly shown by XRD. Long-term washing by nitric acid induces enlargement of micropore volume, increasing the micropore dimension but decreasing the large pore dimension over the mesoporous range. The degree of dehydration has an important role in CO2 adsorption. Metal ionic sites affect both the irreversible CO2 adsorption and the CO2 equilibrium adsorption at low concentration. Li+ ion-exchange brings about a great CO2 adsorption but reduces the CO2-surface interaction due to molecular size effect. Ca2+ ion-exchange has its main effect in the enhancement of CO2 desorption energy. Copyright 1997 Academic Press. Copyright 1997Academic Press

Journal Article↗
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

Toxicologic evaluation of yessotoxin.

Yessotoxin (YTX), originally found in association with diarrhetic shellfish poisoning (DSP), caused neither intestinal fluid accumulation nor inhibition of protein phosphatase 2A. Orally, YTX was not lethal to mice at 1.0 mg/kg. The toxin showed weak cytotoxic and antifungal activities. Neither hemolytic nor ichthyotoxic effect was observed.

Animals↗
PubMed1997

Functional evaluation of hip abductor muscles with use of magnetic resonance imaging.

The hip abductor muscles are considered important for gait and biomechanics of the hip joint; however, their specific function has not been defined precisely. The intensity of magnetic resonance imaging signals in skeletal muscle has been reported to increase immediately after exercise. Making use of this phenomenon, we evaluated the hip abductor muscles. Magnetic resonance imaging was performed after isometric exercise of the hip abductor in three positions (20 degrees of abduction, neutral, and 20 degrees of adduction). The abduction force of the hip was measured with a dynamometer, and electromyographic measurements were made simultaneously for the same hip positions. Additionally, magnetic resonance imaging was performed after one-legged stance. As the hip was more adducted, the signal intensity increased on the scans. The values for muscle force, as evaluated with the dynamometer and integrated electromyography, also supported the results. The increase in signal intensity of the gluteus minimus at 20 degrees of abduction and after one-legged stance was significantly greater than that of the gluteus medius (p < 0.0001 and p < 0.0001, respectively). The results of this study indicate that the gluteus minimus muscle, along with the gluteus medius, plays an important role in hip abduction, gait, and stabilization of the pelvis.

Adult↗
PubMed1997

The effect of age on retrieval of local anesthetic solution from the epidural space.

UNLABELLED: We conducted this prospective study to determine whether advancing age is correlated with retrieval of local anesthetic solution from the epidural space. Three hundred forty-six patients (ASA physical status I or II, 20-93 yrs of age, 177 female and 169 male patients) undergoing epidural anesthesia were enrolled. The epidural space was identified by a loss of resistance technique using air, and a catheter was introduced 3 cm. Three milliliters of 2% lidocaine with epinephrine was injected as a study dose by hand at a rate of 1 mL/s with the patient in the supine position. The syringe was immediately aspirated to retrieve the local anesthetic solution. A retrieved volume of 0.5 mL or more with a glucose concentration less than 6 mg/dL was defined as retrieval positive, and a volume of less than 0.5 mL was defined as retrieval negative. There was a significant correlation between age and retrieval volume among all the patients (Y = 0.008X-0.222, P < 0.0001) with a significant increase in the positive retrieval incidence and volume from the patients in their 50s (11%, 0.6 +/- 0.3 mL) to the patients in their 60s (26%, 1.0 +/- 0.6 mL) (P < 0.05 for both). The incidence of positive retrieval and the retrieval volume were greater in the patients in their 60s and older (30%, 1.1 +/- 0.63 mL) than in the younger than 60 (10%, 0.6 +/- 0.3 mL) (P < 0.0001 and P < 0.001). The glucose concentration was 2.3 +/- 1.2 mg/dL in the positive cases. We conclude that there is a weak positive correlation between age and the local anesthetic solution retrieved from the epidural space. IMPLICATIONS: We conducted a study in 346 patients to determine whether advancing age could be correlated with retrieval of local anesthetic solution from the epidural space. We found a weak positive correlation between advanced age and the amount of solution retrievable from the epidural space. Further studies are required to determine whether this phenomenon may call for dose adjustments in patients aged more than 60 yrs.

Adult↗
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

A press-through-pack in the larynx.

A case of a 96-year-old male with a foreign body in the larynx is reported. The foreign body was a press-through-pack (PTP), a plastic packing for medicine, 16 mm x 16 mm x 3 mm in size. The PTP was safely removed from the larynx under general anesthesia.

Aged↗
PubMed1997

Preliminary study of improved perception of words with the same sound but different intonation in tinnitus patients following electrical stimulation of the ear.

The present study aimed to explain how tinnitus relief following electrical promontory stimulation affects detection of changes in pitch frequency. To determine the effects of tinnitus relief on the auditory system. Japanese words with the same sound but different intonation were used to verify the effects of tinnitus relief on pitch detection in tinnitus patients Eight out of 11 patients experienced relief of tinnitus following treatment. The averaged number of the ratio in 8 patients with relief of tinnitus, 0.58, was significantly higher (p < 0.02) than that in 3 patients without relief, 0.15. In comparison with averaged hearing level, there was no significant difference in averaged hearing level between 8 patients with relief of tinnitus (52.4 dBSL; SD: 11.4) and 3 without relief of tinnitus (58.0 dBSL; SD: 14.7) (p > 0.68). No significant difference in age between patients with and without relief of tinnitus was observed.

Aged↗
PubMed1997

Improved word perception in tinnitus patients following electrical stimulation of the ear: a preliminary report.

The present study showed that there were close relationships between tinnitus relief and improved word perception by means of a grammatically correct but non-sense Japanese word perception test. Fourteen out of 20 patients reported tinnitus relief and improvement in hearing. Nine out of the 14 patients were thought to be significantly improved in word perception. Improved word perception was observed in 7 out of 10 patients whose ears tested were opposite to ears treated while in 2 out of 10 patients whose ears tested were the same as ears treated. Improved word perception was observed in 5 patients at one segment, 2 patients at two segments and 2 patients at three segments. Improved word perception was observed in one patient at the first segment, 5 patients at the second segment, 5 patients at the third segment and 5 patients at the fourth segment. There were no significant differences in hearing level nor age in patients with and without relief of tinnitus.

Electric Stimulation↗
PubMed1997

Improved word perception following electrical stimulation of the ear in hearing-impaired patients without tinnitus.

Improved word perception in hearing-impaired patients following electrical stimulation of ears was shown by means of a grammatically correct but non-sense Japanese 4-segment sentence perception test. Improved word perception was reported in 15 out of 20 patients without tinnitus following electrical stimulation of ears. In 11 out of 15 patients, the number of incorrect words significantly decreased, showing that electrical stimulation of ears improved word perception. Improved word perception was observed in 5 out of 8 patients whose tested ears were contralateral to treated ears while in 8 out of 12 patients whose tested ears were the same as treated ears. The present study suggests that electrical stimulation of ears improves word perception in hearing-impaired patients without tinnitus.

Aged↗
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↗
PubMed1997

[Development of core/targetoid fibers in the diaphragm of chronically hypercapnic rats].

We tested the hypothesis that chronic hypercapnia contributes to the development of core/targetoid fibers in ventilatory muscles. Five Wistar rats were kept in 5% CO2 in air for 13 weeks. Arterial blood gases (mean +/- SE) were pH 7.402 +/- 0.017, PaCO2 47.4 +/- 2.4 Torr, and PaO2 105.2 +/- 13.2 Torr. While the rats were chronically hypercapnic, their mean minute ventilation was about 1.7 times higher than that of rats that breathed air. This level was maintained throughout the exposure to CO2. Approximately 6% to 12% of the diaphragmatic type-I fibers were replaced by core/targetoid fibers in 3 of 5 chronically hypercapnic rats but not in the 3 control rats. Chronic hypercapnia may have continuously stimulated the respiratory center and resulted in more work done by the ventilatory muscles. Long-term overuse of the ventilatory muscles, which may occur in patients with chronic respiratory failure, can cause morphological changes in type-I fibers in the diaphragm.

Animals↗