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Biomedical subjects

K Takano

Publications and source records attributed to K Takano.

At least 199 records · Page 11Linked to original sources
PubMed1997

Demonstration of functionally distinct human polymorphonuclear leukocyte fractions by simultaneous measurement of phagocytosis and oxygen radical generation.

Phagocytosis and oxygen radical generation by human polymorphonuclear leukocytes (PMNLs) were studied by a two-color flow cytometric analysis, where the red fluorescent product(s) of hydroethidine was used as an indicator of intracellular generation of oxygen radicals and opsonized zymosan (OZ) as an indicator of phagocytosis. Unstimulated cells formed a single population of cells without any significant fluorescence. PMNLs stimulated by OZ exhibited a high red fluorescence. Most PMNLs phagocytosed OZ and generated oxygen radicals when stimulated by zymosan particles opsonized with human AB serum at concentrations of more than 10%, whereas three distinct subpopulations (designated as R1, R2 and R3) appeared when stimulated by zymosan particles opsonized with 3% serum; R1 cells enhanced neither green nor red fluorescence, R2 cells enhanced green fluorescence but not red fluorescence, and R3 cells enhanced both green and red fluorescence. The R2 cells completely disappeared by the addition of Trypan blue. Most of the R3 cells disappeared by the addition of cytochalasin B. These findings on the three fractions were confirmed by the observation under fluorescence microscopy of cells in each fraction obtained by sorting. In conclusion, PMNLs could be separated into three functionally distinct subpopulations when stimulated by zymosan particles opsonized with a suboptimal concentration of serum.

Cell Differentiation↗
PubMed1997

Radionuclide angiography and ventilation/perfusion studies in two patients with systemic arterial supply to the basal segment of the left lung.

The findings of radionuclide studies in two adult men with systemic arterial supply to the basal segment of the left lung without sequestration are reported. Radionuclide angiography with Tc-99m human serum albumin-diethylenetriamine showed that the lung was perfused by the systemic circulation rather than by the pulmonary artery. Ventilation and perfusion scans with Xe-133 and Tc-99m MAA showed a V/Q mismatch in this area, suggesting the presence of normal bronchial communication without a pulmonary arterial supply. These results also suggest the presence of a left-to-left shunt in the well-ventilated lung in this area. MRI and conventional angiography showed an aberrant artery arising from the descending thoracic aorta, supplying the basal segment of the left lung without a pulmonary artery. In both patients, left lower lobectomy showed normal alveobronchial structures without sequestration. Radionuclide angiography and ventilation/perfusion imaging appear to be reliable noninvasive methods for diagnosing this rare anomaly with a left-to-left shunt.

Adult↗
PubMed1997

Ventilation abnormalities in obstructive airways disorder: detection with pulmonary dynamic densitometry by means of spiral CT versus dynamic Xe-133 SPECT.

PURPOSE: To evaluate pulmonary dynamic densitometry (PDD) by means of spiral computed tomography (CT) for detection of ventilation abnormalities in obstructive airways disorders compared with dynamic xenon-133 single photon emission CT. MATERIALS AND METHODS: Eight-second spiral CT was performed during two to three respiratory cycles in six healthy volunteers, 19 patients with airways disorder, and six patients with restrictive lung disease. The data sets were reconstructed as 36 1-second temporally overlapping images at 0.2-second intervals, and regional PDD curves were displayed. Regional ventilation was assessed by means of Xe-133 clearance time. RESULTS: Normal lungs showed smooth, sinusoidal PDD curves with maximal amplitude in lung attenuation change (MALAC) of 54.9 HU +/- 24.5, whereas lungs with obstructive airways disorders with prolonged Xe-133 clearance showed significantly diminished MALAC (31.6 HU +/- 20.1, P < .0001), accompanied by irregularity, asynchronous phase, and deterioration of normal ventral-to-dorsal gradients in MALAC and lung attenuation. Lungs with restrictive diseases without prolonged Xe-133 clearance did not show statistically significant reduction in MALAC. In a total of 251 lung regions, regional MALAC correlated inversely with Xe-133 clearance time (r = -.842). CONCLUSION: PDD by means of spiral CT is acceptable for the detection of ventilation abnormalities in obstructive airways disorder.

Adult↗
PubMed1997

Abdominal aortic aneurysm: rupture associated with the high-attenuating crescent sign.

PURPOSE: To determine the histopathologic features of the ruptured abdominal aortic aneurysm associated with the high-attenuating crescent sign on computed tomographic (CT) scans and to suggest a possible mechanism for the rupture. MATERIALS AND METHODS: Histopathologic examination was performed with specimens from six patients with a ruptured aneurysm associated with the high-attenuating crescent sign and from eight patients with a nonruptured aneurysm and in whom the high-attenuating crescent sign was not present. RESULTS: Acute hemorrhage in the mural thrombus or aneurysmal wall coincident with the high-attenuating crescent sign was present in all six patients with a ruptured aneurysm. Clefts with seeping blood in the mural thrombus were seen in four patients with a ruptured aneurysm; intact specimens of the mural thrombus were not obtained in two patients because the hemorrhagic thrombus was fragile. Clefts with seeping blood were scattered from the inner to the outer layers of the mural thrombus. In the eight patients with uncomplicated aneurysm, no hemorrhage in the mural thrombus or aneurysmal wall was noted, and no clefts were seen. CONCLUSION: The cause of high-attenuating crescents in a ruptured aneurysm may be attributed to hemorrhage in the mural thrombus or in the aneurysmal wall.

Adult↗
PubMed1997

Clinical utility of a newly developed pressure swing adsorption-type oxygen concentrator with a membrane humidifier.

The clinical utility of the newly developed pressure swing adsorption (PSA)-type oxygen concentrator with a membrane humidifier that does not require added water for humidification was evaluated in 13 patients with chronic pulmonary disease who were receiving long-term oxygen therapy. PaO2 and the relative humidity were measured when the patient breathed air and oxygen from the new device via a nasal cannula. After using the new concentrator for 5 h, the patients were asked whether they experienced dry nasal passages or a dry throat. A significant difference between the PaO2 measured while the patients breathed room air and while they breathed oxygen from the new device was observed. A significant difference was observed between the relative humidity of room air (44.7 +/- 18.6%) and that of the oxygen flow (72.7 +/- 14.8%) from the new device. None of the patients experienced dry nasal passages, dry throat, or any other adverse effects. Since this new PSA-type oxygen concentrator with a membrane humidifier supplies well-humidified nasal oxygen without water, laborious cleaning of the container and changing of the water are not necessary, and may help to improve the patient's quality of life.

Aged↗
PubMed1997

Glycine site antagonist attenuates infarct size in experimental focal ischemia. Postmortem and diffusion mapping studies.

BACKGROUND AND PURPOSE: The glycine site on the N-methyl-D-aspartate (NMDA) receptor complex offers a therapeutic target for acute focal ischemia, potentially devoid of most side effects associated with competitive and noncompetitive NMDA antagonists. METHODS: A novel glycine receptor antagonist, ZD9379, was studied in 70 Sprague-Dawley rats using the suture occlusion model of permanent middle cerebral artery occlusion (MCAO). In the first experiment, 20 rats received an initial bolus of vehicle or 10 mg/kg ZD9379 (n = 10 in each group) 30 minutes after MCAO, followed by a continuous infusion of the same dose per hour for 4 hours. Diffusion-weighted MRI with echo-planar acquisition was used to generate maps of the apparent diffusion coefficient (ADC) of water. In a second experiment, 50 rats were assigned to five groups: vehicle and 10, 5, 2.5, and 1 mg/kg ZD9379 (n = 10 in each group) with the same dosing protocol but no imaging. In both experiments, infarct volume was determined by 2,3,5-triphenyltetrazolium chloride staining. RESULTS: In the first experiment, before therapy was begun, there was no significant difference in ADC-derived ischemic lesion volume between the two groups. Over time, the 10-mg/kg ZD9379-treated rats had a significant delayed regional recovery of reduced ADC values in the peripheral parietal cortex (P = .0156). Postmortem corrected infarct volume at 24 hours after MCAO was significantly smaller in the group treated with 10 mg/kg ZD9379 than in the vehicle group (119.2 +/- 52.2 versus 211.2 +/- 50.0 mm3 [mean +/- SD]; P = .0008; a reduction of 43.6%). In the second experiment, postmortem corrected infarct volumes in rats receiving 10, 5, and 2.5 mg/kg ZD9379 were significantly smaller than in those receiving vehicle, a reduction of 42.6%, 51.4%, and 42.9%, respectively (P = .0001). CONCLUSIONS: This study demonstrates that 2.5- to 10-mg/kg doses of ZD9379 initiated 30 minutes after MCAO significantly reduced infarct size. Diffusion mapping disclosed a delayed treatment effect of this glycine antagonist in focal ischemia, confirmed by the postmortem study.

Animals↗
PubMed1997

Gi3 mediates somatostatin-induced activation of an inwardly rectifying K+ current in human growth hormone-secreting adenoma cells.

SRIF activates an inwardly rectifying K+ current in human GH-secreting adenoma cells. Activation of this K+ current induces hyperpolarization of the membrane and abolishment of action potential firing. This mechanism is an essential mechanism for SRIF-induced decrease in intracellular Ca2+ concentration and inhibition of GH secretion. The activation of the inwardly rectifying K+ current is mediated by a pertussis toxin-sensitive G protein. In this article, the expression of the pertussis toxin-sensitive G protein alpha-subunits in the human GH-secreting adenoma cells were analyzed by RT-PCR, and the G protein transducing the SRIF-induced activation of this inwardly rectifying K+ current was investigated. RT-PCR of the messenger RNA from two human GH-secreting adenomas revealed that all G alpha(i1), G alpha(i2), G alpha(i3), and G alpha(o) were expressed in these adenomas. Primary cultured cells from these two adenoma cells were investigated under the voltage clamp of the whole-cell mode. Specific antibodies against the carboxyl terminus of G protein alpha-subunits were microinjected into the cells. Microinjection of antibody against the carboxyl terminal sequence of G alpha(i3) attenuated the SRIF-induced activation of the inwardly rectifying K+ current, whereas antibody against the common carboxyl terminal sequence of G alpha(i1) and G alpha(i2) did not. These data indicate that the G protein transducing the SRIF-induced activation of the inwardly rectifying K+ current is Gi3.

Adenoma↗
PubMed1997

Clinical trials of GH treatment in patients with Turner's syndrome in Japan--a consideration of final height. The Committee for the Treatment of Turner's Syndrome.

Clinical trials of human GH (hGH) therapy in Turner's syndrome were started in 1986. Between 1986 and 1990. 362 patients were enrolled; 115 were treated for more than 6 years. The age at the start of treatment ranged from 5 to 18 years (mean 10 years). Fifty-one patients received hGH at a weekly dosage of 0.5 IU/kg and 64 received 1.0 IU/kg by daily s.c. injection. Both treatment groups showed a statistically significant growth increase during the initial 4 years of treatment. The rate of increase in height was significantly greater for the initial 2 years with the high dose than with the low dose. The increases in height over 6 years of treatment (expressed by S.D. score for chronological age) were 1.48 +/- 0.8 with 0.5 IU/kg per week and 1.80 +/- 1.0 with 1.0 IU/kg per week. To date, 260 patients have stopped GH therapy. In 32% of them, the height attained was above the -2 S.D. value for normal girls. In 27%, the growth rate was not sufficient when they stopped treatment. The mean final height (growth rate < or = 1.0 cm/year) of patients treated for more than 6 years was 142.2 +/- 6.5 cm (n = 15) with 0.5 IU/kg per week, and 144.3 +/- 3.9 cm (n = 15) with 1.0 IU/kg per week. The adult height was improved by GH treatment, although final height did not differ statistically between the two dose regimens. No remarkable adverse events occurred during the treatment. These results indicate that hGH treatment improves the final height in patients with Turner's syndrome.

Adolescent↗
PubMed1997

Antiphospholipid syndrome complicated by thrombosis of the superior mesenteric artery, co-existence of smooth muscle hyperplasia.

A 37-year-old woman underwent an emergency operation at our hospital because of severe abdominal pain and ileus. Most of her small intestine and ascending colon were observed to have become necrotic due to occlusion of her superior mesenteric artery (SMA). Pathological findings of the resected intestine revealed that her SMA was completely thrombosed 2 cm distal from its origin with smooth muscle proliferation. Post-surgical blood analysis of her pre-operative serum was positive for lupus anticoagulant and antinuclear antibodies. She noticed vaginal bleeding due to missed abortion on the 31st day after the operation. We diagnosed her acute abdominal pain to be that of antiphospholipid syndrome associated with her pregnancy.

Abdominal Pain↗
PubMed1997

Efficacy of newly developed pressure swing adsorption type oxygen concentrator with membrane humidifier: comparison with conventional oxygen concentrator with bubble water humidifier.

To examine the clinical efficacy of a newly developed pressure swing adsorption (PSA) type oxygen concentrator with a membrane humidifier without added water for humidification, the new machine was compared with the conventional PSA type oxygen concentrator with bubble water humidifier in 10 patients with chronic pulmonary disease. Relative humidity, partial pressure of oxygen (PaO2) and partial pressure of carbon dioxide (PaCO2) in arterial blood were measured when the patient breathed air and oxygen from the oxygen concentrators. No significant difference between PaO2 while breathing oxygen flow from the new machine and that while breathing oxygen from the conventional oxygen concentrator was observed. All patients answered that there was no difference on subjective impression between breathing oxygen from the new machine and from the conventional oxygen concentrator. Sufficient relative humidity (above 50%) of oxygen flow was obtained by using membrane humidifier. Since this machine saves the troublesome procedures of cleaning the container and changing the water, it will be beneficial to the patients who use a PSA-type oxygen concentrator in their home.

Aged↗
PubMed1997

[Immunomodulatory effect of daily low-dose cisplatin treatment].

Immunomodulatory effects of daily low-dose cisplatin treatment were investigated on compromised patients with advanced or recurrent gastrointestinal cancer. One case of esophageal cancer, 7 of gastric cancer, 2 of colorectal cancer, 1 of carcinomatous peritonitis from unknown origin, and 1 of hepatocellular carcinoma, were treated by daily low-dose cisplatin combined with 5-FU or tegafur, and their ECOG Performance Status Score (PS), number of lymphocytes, and CD3 zeta chain expression of peripheral blood lymphocytes were studied to compare with the effects of treatment. Seven patients with esophageal cancer and gastric cancer showed a partial response and their PS was improved, and the number of lymphocytes and CD3 zeta chain expression of lymphocytes was increased. However, in two patients with progressive disease, a decreased number of lymphocytes and less expression of CD3 zeta chain were seen.

Adjuvants, Immunologic↗
PubMed1996

Corticotropin-releasing hormone excites adrenocorticotropin-secreting human pituitary adenoma cells by activating a nonselective cation current.

The mechanisms of corticotropin-releasing hormone (CRH) induced excitation of ACTH-secreting adenoma cells were investigated using the perforated whole-cell clamp technique and intracellular Ca2+ concentration ([Ca2+]i) measurement. CRH depolarized ACTH-secreting adenoma cells by activating a nonselective cation current that showed slight inward rectification. This channel did not seem to be a member of the Ca(2+)-activated cation currents because it was activated even when the [Ca2+]i was chelated below 50 nM. The activation of the current was induced by protein kinase A-mediated pathways. By [Ca2+]i measurement, CRH increased [Ca2+]i of these cells dependently on voltage-gated Ca2+ current. This CRH-induced [Ca2+]i increase was abolished in Na(+)-free extracellular solution, but was not abolished by the addition of 5 microM tetrodotoxin to the extracellular solution. CRH-induced ACTH secretion from the cultured adenoma cells was also abolished in Na(+)-free extracellular solution, but not in tetrodotoxin-containing extracellular solution. These data indicate that a Na+ current (maybe the nonselective cation current) other than voltage-gated Na+ current plays an important role in CRH-induced [Ca2+]i increase and ACTH secretion. CRH also activated a nonselective cation current in nonadenoma human corticotrophs, suggesting that the activation of a nonselective cation current is a physiological mechanism of CRH-induced excitation in human corticotrophs.

Adenoma↗
PubMed1996

Proadrenomedullin NH2-terminal 20 peptide inhibits the voltage-gated Ca2+ channel current through a pertussis toxin-sensitive G protein in rat pheochromocytoma-derived PC 12 cells.

The effect of proadrenomedullin NH2-terminal 20 peptide (PAMP) on the voltage-gated Ca2+ channel current was investigated using the perforated whole-cell clamp technique on NGF-treated PC12 cells. PAMP inhibited the Ba2+ current through N-type Ca2+ channels in a concentration dependent manner. Injection of GDPbetaS into the cell abolished the inhibition while injection of GTPgammaS into the cell made the inhibition irreversible, indicating that the PAMP-induced inhibition of the voltage-gated Ca2+ channel was mediated by a G protein. The inhibition was abolished by pretreating the cells with pertussis toxin, indicating that a pertussis toxin-sensitive G protein was involved in the signal transduction mechanism of PAMP. The present study revealed that the inhibition of catecholamine secretion from sympathetic nerve endings by PAMP could be explained by the inhibition of N-type Ca2+ channels, which was mediated by pertussis toxin-sensitive G protein.

Adrenomedullin↗
PubMed1996

In vitro fertilization and microinsemination with round spermatids for propagation of nephrotic genes in mice.

The ICGN is an inbred strain of mice with a hereditary nephrotic syndrome of an unknown cause. The disease progresses to renal failure, resulting in the deterioration of the systemic condition and in a drastic reduction of reproductive capacity. The present study was undertaken to determine if in vitro fertilization (IVF) and microinsemination using round spermatids could ameliorate the reduced fertility of ICGN mice. Mature oocytes (9.4 +/- 1.1 per mouse) were obtained from PMSG/hCG-primed females 2 to 5 mo of age. When spermatozoa from males aged 3 to 4 mo was used for IVF, a high fertilization rate (82.6%) was achieved and a high rate of embryos developed into blastocysts (92.6%). When spermatozoa from males aged 5 to 7 mo was used, the rates of fertilization and development to blastocysts were significantly lower (63.9 and 47.1%, respectively; P < 0.001). However, the production rate of offspring after embryo transfer was satisfactory irrespective of the age of males (59.1%). When males older than 9 mo were used, no fertilization was achieved due to the very poor motility of the spermatozoa. Microinsemination techniques with round spermatids (electrofusion and intracytoplasmic injection) resulted in the production of normal offspring from the older males, including one azoospermic case. These findings indicate that a conventional IVF technique and microinsemination using round spermatids can be used for propagating mutant genes which cause poor reproductive ability in mice.

Journal Article↗