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Biomedical subjects

M Kumagai

Publications and source records attributed to M Kumagai.

At least 73 records · Page 4Linked 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

Treatment of the survivors from the Nagoya air crash.

Six patients were taken to our hospital alive just after the air crash at Nagoya Airport in 1994. On admission, all patients suffered from profound shock which rapidly progressed. Serum albumin and hemoglobin levels, and platelet count decreased on admission or soon after. The four patients who died could not recover from the shock and associated rapid deterioration of neurological signs. However, two patients were successfully treated with massive transfusion of packed red blood cells, fresh frozen plasma, fresh blood, and/or platelet concentrate and survived to discharge. We recommend addition of albumin to the transfusate in such cases.

Accidents, Aviation↗
PubMed1998

Moyamoya disease associated with pulmonary sarcoidosis--case report.

A 61-year-old female presented with a unique case of moyamoya disease associated with pulmonary sarcoidosis. She was admitted for sudden onset of left temporalgia with episode of numbness on face, tongue, and upper extremity on the right side. The next morning, she had symptoms of Gerstmann syndrome and her ability to speak was disturbed. Her medical history included radical resection of lung cancer on the right side. She had no symptoms of pulmonary sarcoidosis. Neuroimaging showed an infarction in the left occipital lobe. Angiography showed occlusions of the bilateral internal carotid arteries at the supraclinoid portions. Subsequently, a left superficial temporal artery-middle cerebral artery anastomosis with encephalo-myo-synangiosis was performed. Ninety-three days after admission, she suddenly developed dyspnea which resulted in death 3 hours later. Autopsy findings showed typical epithelioid granulomas of sarcoid type in the lymph nodes of the peribronchus, lung, and liver. Thrombotic emboli were found in the bilateral pulmonary arteries, and marked fibrous intimal thickening in the bilateral internal carotid arteries. Immunological reaction with inflammatory events may cause pathological changes in patients with moyamoya disease or sarcoidosis. The co-incidence in this case suggests that some common inflammatory events may be involved in the pathogenesis of these diseases.

Carotid Artery, Internal↗
PubMed1998

Effect of chronic furosemide administration on acid-base balance in patients with chronic hypercapnic respiratory failure.

We quantitatively analyzed the effect of long-term administration of oral furosemide on the PaCO2 - H+ relationship in patients with chronic hypercapnic respiratory failure. In this study we measured arterial blood gases of eighteen outpatients (mean duration of visits, 7.6 years; mean rise of PaCO2, 15.4 mmHg). We obtained linear regression lines for PaCO2 - H+, and determined their Y-axis intercepts and slopes. The results indicated that an increase in the administered dose of furosemide decreased linearly the Y-axis intercept of the regression line [(Y-intercept) = - 6.9(dose of furosemide) + 30.9, r = 0.81], and increased linearly the slope of the regression line [(slope) = 0.094(dose of furosemide) + 0.22, r = 0.74]. Thus, the regression line of the PaCO2 - H+ relationship moved downward and became steeper at higher doses of furosemide. The regression lines for each dose of furosemide crossed at a PaCO2 of 75 mmHg. We concluded that there is a mutual interaction between the renal and respiratory mechanisms for acid-base balance in chronic hypercapnia and the effect of furosemide on the PaCO2 - H+ relationship is negligible in severe hypercapnia.

Acid-Base Equilibrium↗
PubMed1998

Regulation of intracranial pressure in the rat with chronic moderate hypercapnia.

STUDY OBJECTIVES: In this animal study we investigated whether CO2-induced intracranial hypertension was sustained in chronic hypercapnia. DESIGN: We kept five rats in a 10% CO2-air mixture (PaCO2 73.4 +/- 6.2 Torr, mean +/- 1SD) for 22 weeks, and then measured the rats' intracranial pressure while breathing the 10% CO2- air mixture or the room air. RESULTS: The intracranial pressures recorded during chronic hypercapnia in systole and diastole were 7.0 +/- 1.9 and 5.4 +/- 1.6 mm Hg, respectively. When the rats were acutely exposed to the room air (PaCO2, 51.9 +/- 10.2 Torr), the intracranial pressures in systole and diastole were 6.1 +/- 1.4 and 5.0 +/- 0.8 mm Hg, respectively, were not significantly different from those during hypercapnia (P>0.05, paired t-test). CONCLUSIONS: The intracranial pressure in rats with chronic moderate hypercapnia was not significantly different from normocapnic rats, and this change was associated with a blunting of intracranial pressure autoregulation.

Animals↗
PubMed1998

Inhibition of encystation of Entamoeba invadens by aphidicolin.

Effects of aphidicolin, a specific inhibitor of eukaryotic nuclear replicative DNA polymerases, on the growth and encystation of a reptilian parasitic protozoan Entamoeba invadens were evaluated. Aphidicolin blocked the growth of axenic E. invadens strain IP-1 in a dose-dependent manner. Encystation induced by the glucose depletion and osmotic pressure was also inhibited by aphidicolin. The inhibition was almost complete when trophozoites were treated with the drug before being transferred to encystation medium containing the drug. The inhibitory effect of aphidicolin on E. invadens growth was abrogated by removal of the drug, and exposure to 3 microg/ml of the drug for at least 7 days had little effect on the viability. Encystation was also restored by removal of the drug. These results suggest that the trophozoites accumulated at G1/S border by treatment with aphidicolin cannot encyst upon induction of encystation so that they need DNA synthesis before encystation.

Animals↗
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↗
PubMed1998

Response of cerebral oxygen metabolism in the head-up position during laparoscopic cholecystectomy.

To clarify the influence of the head-up position on cerebral oxygen metabolism during laparoscopy with CO2 insufflation in 12 patients who underwent laparoscopic cholecystectomy, changes in the concentrations of cerebral oxyhemoglobin (HbO2), deoxyhemoglobin (Hb), total hemoglobin (total Hb) and oxidized cytochrome aa3 (Cyt aa3) were measured by use of near-infrared laser spectroscopy. Anesthesia was maintained with nitrous oxide (66%), oxygen, and sevoflurane. Pneumoperitoneum was maintained at an intraabdominal pressure of 10-12 mm Hg by use of CO2. Minute ventilation was adjusted to maintain end-tidal CO2 tension (P(ET)CO2) between 35 and 40 mm Hg during the procedure. Patients were moved from supine to the head-up (20 degree) position before intraabdominal manipulation. The concentration of HbO2 decreased significantly when patients were moved to the head-up position and 30 min thereafter. It remained significantly low after they were returned to the supine position and at the end of surgery. The concentration of Hb was unchanged during the study. Therefore, the concentration of total Hb decreased significantly when patients were moved to the head-up position, as well as 30 min thereafter. It remained significantly low after they were returned to the supine position and at the end of surgery. The concentration of Cyt aa3, however, did not change significantly during the study. These results suggest that the head-up position during laparoscopic cholecystectomy decreases cerebral HbO2 and total Hb.

Adult↗
PubMed1998

Three cases of primary lung cancer undetected by an annual checkup.

An annual check by chest roentgenogram is very important for the early detection of lung cancer. We present three cases of primary lung cancer which were not detected by the double check system or previous examination. The three patients visited our hospital for evaluation of an ill-defined opacity in the upper lobe of the lung. In the three cases, no abnormality had been reported in the previous year's annual chest X-ray, and we concurred in the decisions. The correct diagnoses of the three cases were well or poorly differentiated adenocarcinoma, and were still amenable for surgical therapy. A poorly defined tumor in this region is very difficult to detect because of superimposed opacities of other anatomical structures. When a questionable shadow in this region is found but without the typical radiological features of lung cancer, it is important to search for indirect indications of adenocarcinoma. These may include fibrotic changes and absence of inflammation. In our cases, the increased number of normal-size bronchi penetrating the ill-defined tumor, seem to have diagnostic significance.

Adenocarcinoma↗
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↗