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Biomedical subjects

Y Oka

Publications and source records attributed to Y Oka.

674 records · Page 38Linked to original sources
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[Study of components in crude drugs by head space gas chromatography. I. Components of Asiasari radix].

Determinations of volatile components of essential oil contained in Asiasari Radix were studied by head space gas chromatography. The head space gas, which was generated by heating 0.2 g of crude drug with 1.0 ml of water at 90 degrees C for 45 min, was analyzed directly by gas chromatography or gas chromatography-mass spectrometry. This method was rapid, and did not require tedious procedures and time consuming, and without contamination of the column.

Chromatography, Gas↗
PubMedDate not supplied

Heat-induced drug resistance is associated with increased expression of Bcl-2 in HL60.

HL60 cells underwent apoptosis with heat treatment, i.e. exposure to 42 degrees C for 120 minutes. Cells exposed to the same temperature for 30 minutes became resistant to subsequent, otherwise lethal, heat shock. These thermotolerant cells also acquired resistance to anti-cancer drugs including daunorubicin and VP16. We found that mild heat shock upregulates not only HSP70 but also BCL-2, though BCL-2 has not previously been recognized as a heat-inducible protein. Expression of BCL-2 closely paralleled resistance to subsequent exposure to anticancer drugs. The present results suggest that BCL-2 may play a role in heat-induced drug resistance.

Antibiotics, Antineoplastic↗
PubMedDate not supplied

Prevention of spinal cord injury after cross-clamping of the thoracic aorta.

Paraplegia has been a devastating and unpredictable complication following cross-clamping of the thoracic aorta. In this study, the effect of the pressure gradient between the aortic pressure distal to occlusion and cerebrospinal fluid pressure (CSFP), defined as relative spinal cord perfusion pressure (RSPP), on the development of spinal cord injury was investigated. In 32 mongrel dogs, the thoracic aorta just distal to the left subclavian artery was cross-clamped. After a complete loss of somatosensory evoked potentials (SEP) had been confirmed, the dogs were divided into six groups by an additional cross-clamp interval and RSPP as follows: Group I (n = 6): 0 mmHg for 10 minutes; Group II (n = 8): 0 mmHg for 20 minutes; Group III (n = 3): 7.5 mmHg for 20 minutes; Group IV (n = 3): 7.5 mmHg for 40 minutes; Group V (n = 6): 15 mmHg for 40 minutes and Group VI (n = 6): 15 mmHg for 60 minutes. RSPP was adjusted by either withdrawal of cerebrospinal fluid or injection of normal saline solution into the subarachnoid space. SEP were generated by the stimulation of bilateral peroneal nerves. The incidence of postoperative paraplegia was 0% in Groups I and V, 33% in Group III, 50% in Group VI and 100% in Groups II and IV. This study showed that RSPP plays an important role in the development of spinal cord injury during cross-clamping of the thoracic aorta. Therefore, RSPP should be maintained at as high a level as possible in order to prevent spinal cord injury even if SEP disappear during aortic occlusion.

Animals↗
PubMedDate not supplied

[Effect of reperfusion therapy on the prognosis of acute myocardial infarction complicated by left heart failure: prediction based on the acute course of left ventricular heart failure].

This study evaluated the correlation between the acute course and prognosis of patients with acute myocardial infarction complicated by heart failure. Heart failure was defined as a mean pulmonary capillary wedge pressure equal to or greater than 20 mmHg with radiographic evidence of pulmonary congestion during hospitalization in the coronary care unit. A total of 77 heart failure patients underwent primary percutaneous transluminal coronary angioplasty or thrombolysis. Twelve patients who died within the first 3 days (group I) had a higher incidence of unsuccessful reperfusion (50 vs 19%, p < 0.05) and cardiogenic shock (64 vs 4%, p < 0.01), compared with the 65 patients who survived at least the initial 4 days (group II). These 65 patients were classified into three subgroups according to the course of heart failure: early regression type (group IIA, n = 38); prolonged type (group IIB, n = 18); delayed-onset type (group IIC, n = 9). Patients in group IIB had a higher incidence of multivessel disease than group IIA. Patients in group IIC had a higher incidence of unsuccessful reperfusion. Cardiac index in group IIB was lower than in group IIA (2.50 +/- 0.70 vs 1.91 +/- 0.39 l/min/m2). Changes in left ventricular ejection fraction were 4.1 +/- 9.2% in group IIA, -6.6 +/- 16.8% in group IIB, and 0.9 +/- 7.3% in group IIC. The hospital mortality rate was 0% in group IIA, 11% in group IIB, and 33% in group IIC, the reinfarction rate was 0, 17 and 22%, and sustained arterial patency was demonstrated in 81, 62 and 43%, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMedDate not supplied

Retinoic acid combined with GM-CSF induces morphological changes with segmented nuclei in human myeloblastic leukemia ML-1 cells.

The effects of all-trans retinoic acid (ATRA), either alone or in combination with GM-CSF, on the induction of differentiation of a human myeloblastic leukemia cell line, ML-1, were investigated. ATRA alone caused only slight induction of NBT-reducing activity even at a high concentration (10(-7) M), but when combined with GM-CSF, it led to remarkable increase in the induction of NBT-reducing activity. Synergistic effect of both agents was also observed on morphological changes and the inhibition of cell proliferation. When ATRA or GM-CSF was used alone, neither parameter was changed substantially for long periods of up to 9 days. However, the combination of both agents induced remarkable morphological changes with segmented nuclei and also suppressed DNA-synthesizing activity.

Cell Nucleus↗