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Biomedical subjects

N Nakano

Publications and source records attributed to N Nakano.

At least 19 recordsLinked to original sources
PubMed1992

[Relationship between anaerobic threshold and breathlessness during exercise].

We studied the possibility that during incremental exercise anaerobic threshold (AT) is associated with an increase in breathlessness in subjects with increased impedance or respiratory system. Six patients with chronic lung diseases (CLD) and six healthy subjects performed cycle ergometer exercise under two conditions; with free resistive loading and with 9 cmH2O/l/sec of inspiratory resistive loading (IRL). Ventilation, respiratory pattern, VO2, VCO2, were measured every 15 sec by a metabolic cart, Minato Respiromonitor RM 300. AT was determined by V-slope method. Mouth occlusion pressure (P0.1) was also measured in six subjects during exercise. The subjects selected a number of modified Borg scale (psi) to express their breathlessness during exercise by pushing a electrically potentiated remote button. Slopes of changes in psi with increasing work-load, delta psi/delta watt-slope, were calculated before and after V-slope AT, and each inflection point of VE, respiratory rate, VT/Ti, and VCO2. In order to evaluate which parameters are the most responsible for a change in psi, statistical significance (P-value) in changes of slope of each parameters were compared. The delta psi-slope increased with the highest significance after AT point. Under IRL the significance was more pronounced. There was a highly significant linear correlation between P0.1 and psi during exercise both under free resistive loading and IRL. In addition the increase of P0.1 with incremental exercise was characterized by a presence of inflection at a workload of V-slope AT in most of the subjects. From these results it was concluded that anaerobic threshold was closely associated with an increase of breathlessness during exercise via enhancing respiratory motor command.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

T cell receptor V gene usage of islet beta cell-reactive T cells is not restricted in non-obese diabetic mice.

Five islet-reactive T cell clones were established from islet-infiltrating T cells of non-obese diabetic (NOD) mice. All clones expressed CD4, but not CD8, and responded to islet cells from various strains of mice in the context of I-ANOD. They could induce insulitis when transferred into disease-resistant I-E+ transgenic NOD mice. The T cell receptor (TCR) sequences utilized by the clones were determined. Their usage of TCR V and J segments was not restricted but was rather diverse. One of the clones utilized V beta 16. The expression of V beta 16 was significantly reduced in I-E+ transgenic NOD, suggesting the possibility that the islet-reactive T cell clone expressing V beta 16 may be deleted or inactivated by I-E molecules. This clone might be one of the candidates that triggers insulitis.

Animals↗
PubMed1991

Specific depletion of the B-cell population induced by aberrant expression of human interferon regulatory factor 1 gene in transgenic mice.

Interferons (IFNs) are well known both as antiviral proteins and as potent regulators of cell growth and differentiation. In fact, IFNs inhibit growth of various normal and transformed cell types. Previously, a nuclear factor, IRF-1 (interferon regulatory factor 1), which binds to type I IFN and some IFN-inducible gene promoters, was identified and cloned. Since the IRF-1 gene is both virus and IFN inducible, an intriguing issue is raised as to whether the IRF-1 gene is functioning in IFN-mediated regulation of cell growth and differentiation. In this study, we generated transgenic mice carrying the human IRF-1 gene linked to the human immunoglobulin heavy-chain enhancer. In the transgenic mice, all the lymphoid tissues examined showed a dramatic reduction in the number of B lymphocytes (B cells). Preparation and analysis of bone marrow cells from the chimeric mice indicated that the bone marrow is the effective site for specific depletion of the B-cell population. In fact, transgenic bone marrow cells cocultured with a bone marrow-derived stromal cell line revealed an altered B-cell maturation pattern.

Animals↗
PubMed1991

Induction of IgE-Fc receptor (Fc epsilon R2/CD23) expression on lymphocytes from patients with mite-allergic bronchial asthma by mite allergen.

The present study was designed to clarify whether Fc epsilon R2 can be induced on lymphocytes of patients with bronchial asthma by stimulation with specific antigen. Expression of Fc epsilon R2 on freshly isolated lymphocytes (at 0 hour) was significantly higher in both patients with mite-allergic asthma and those with nonmite-atopic asthma than in healthy individuals. In addition, expression of Fc epsilon R2 on lymphocytes was still higher in patients during acute asthma. Marked induction of Fc epsilon R2 on lymphocytes was observed 48 hours or more after addition of mite-allergen in patients with mite-allergic asthma while no Fc epsilon R2 expression was induced in patients with nonmite-atopic asthma or healthy individuals. Induction of Fc epsilon R2 expression was not observed at 30 minutes, two hours, and five hours, which are equivalent in kinetics to immediate asthmatic response and late asthmatic response in allergen inhalational challenges.

Allergens↗
PubMed1991

[Measurement of enzyme activity of control materials containing human enzymes by IFCC reference methods].

In order to unify interlaboratory clinical enzyme data, a reference method and reference material are necessary for each enzyme. Although reference methods recommended by various societies of clinical chemistry including JSCC are now available for some routinely measured clinical enzymes, the availability of secondary enzyme references or calibrators, limits the practical application of standardization concept for minimizing present interlaboratory variation of enzyme data. Since control sera prepared by adding enzymes from human cell cultures to a pool of human serum may meet the requirements as candidates for such reference materials, we attempted to assign values to 6 enzymes present in the materials by mainly the IFCC reference methods following the procedures as strictly as possible and yet with modifications where necessary. This paper describes each step of the value assignment for accuracy control purposes.

Alkaline Phosphatase↗
PubMed1990

Differential effects of IL-2 and IL-6 on the development of three distinct precursor T-cell populations in the thymus.

Three distinct T-cell precursors: bone marrow cells that express low levels of the Thy-1 antigen but no lineage markers (Thy-1-lo/BM); CD4-, CD8-, and CD3- thymocytes that express low levels of the Thy-1 antigen (Thy-1-lo/Thym); and CD4-, CD8-, and CD3- thymocytes that express high levels of the Thy-1 antigen and the IL-2 R alpha chain (Thy-1+/IL2R+) were isolated by fluorescence-activated cell sorter (FACS). These three populations expanded with different kinetics in the thymus of irradiated recipient mice after intrathymic transfer. When a high dose of human recombinant IL-2 (r-IL-2) or human recombinant IL-6 (r-IL-6) was administered, r-IL-6 accelerated donor Thy-1+/IL2R+ to differentiate, whereas r-IL-2 blocked normal differentiation and expansion of donor Thy-1-lo/Thym, but did not show any significant effect on donor Thy-1+/IL2R+. Neither r-IL-2 nor r-IL-6 worked directly on donor Thy-1-lo/BM in this transfer system.

Animals↗
PubMed1990

HAF, hepatoma aggregation factor produced by Streptomyces sp. strain No. A-6143.

We searched for a new cell aggregation factor for hepatoma AH109A cells, and found one we called HAF in the culture filtrate of Streptomyces sp. strain No. A-6143 isolated from a soil sample. HAF was purified by salting-out with ammonium sulfate. DEAE-cellulose column chromatography, gel filtration on Sephadex G-100, and hydroxylapatite column chromatography, HAF was glycoprotein which had a molecular weight of about 73,000. HAF was stable from pH 6 to 8 at 37 degrees C and up to 40 degrees C at pH 8.0 and the aggregation activity of HAF was maximum around pH 8 at 30 degrees C. The activity was not influenced by some saccharides, but it was inhibited by EDTA and EGTA: moreover HAF activity was restored by the addition of calcium ions. HAF aggregated hepatoma AH136B and COS-7 cells as well as hepatoma AH109A cells, but it was inert to other cancer cells and human erythrocytes. These properties proved that HAF is completely different from other aggregation factors for cancer cells so far reported.

Animals↗
PubMed1990

Exercise performance and limiting factors in patients with chronic lung diseases.

To demonstrate the clinical usefulness of the treadmill exercise test in patients with chronic lung diseases (CLD), 272 consecutive tests done from Jan. 1986 to Dec. 1988 were analyzed. The subjects mainly consisted of patients with chronic obstructive pulmonary disease (COPD) and interstitial lung disease (ILD). With the present incremental treadmill protocol the maximal stage attained by a patient or distance walked were closely related to the patient's maximal oxygen uptake. Comparing symptoms and cardio-pulmonary response, and exercise performance between patients with COPD and those with ILD, there was an evident difference in the exercise limiting factor (s): in the former ventilatory limitation was the most important whereas in the latter gas exchange and oxygen transport was critical. Assessment of breathlessness during the exercise test using the Borg scale was useful in evaluating various therapeutic modalities such as oxygen supplementation. In conclusion, the exercise performance in patients with CLD was properly assessed with the present treadmill protocol and the information derived thereby was of great clinical significance.

Exercise Test↗
PubMed1979

Hypoglycemia in mice administered with fusarenon-X.

Histological observation combined with determination of the serum glucose level and histochemical detection of liver glycogen was undertaken to examine the acute toxicity of fusarenon-X (FX) in mice. Mice intraperitoneally injected with a sublethal dose of the toxin showed rapidly developed hypoglycemia followed by depletion of liver glycogen. Mitotic inhibition was observed in many visceral organs and most markedly in the intestinal crypt cells, where the mitotic figures completely disappeared prior to the increase in number of the degenerated and nucrotic cells. No glycosuria was found. The disturbing effect of FX on the oral glucose tolerance test suggested the involvement of accelerated glycolysis and, more likely, of intestinal malabsorption.

Animals↗
PubMed1979

The tissue distribution and the pattern of excretion of [14C]-13-labeled 12, 13-epoxytrichothec-9-ene in mice and rats.

The distribution in the mouse tissues of 13-[14C]-12,13-epoxtrichothec-9-ene administered intravenously was determined by whole-body autoradiography and by tracing the radioactivity of the tissues oxidized in an Auto Sample Oxidizer. The appearance of the label in urine and feces was also followed by the tracer technique. The distributions of radioactivity in tissues as determined by the two methods were almost identical. On the autoradiograms of mice killed 10 min after the injection, marked blackening of the film was observed at the sites corresponding to the liver, kidney, and bladder with urine, and much less darkening at other sites. The radioactivities contained in the liver, kidney, urine and small intestine were 13.3, 2.3, 2.6 and 10.2% of the dose, respectively. The labeled toxin was rapidly excreted into urine and feces, 56.0 and 4.9% in 6 hr and 66.7 and 28.0% in 24 hr after injection, respectively. Oral administration of the labeled toxin to mother mice resulted in the appearance of radioactivity in the stomach contents of 7-day suckling mice, thus demonstrating indirectly the secretion of the toxin into the milk. An attempt to show a respiratory route of excretion in rats given the radioactive compound orally or intravenously failed to detect any radioactivity in the expired CO2 collected for 6 hr, suggesting that the 14C in the epoxy ring was intact.

Animals↗