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Biomedical subjects

Y Kikuchi

Publications and source records attributed to Y Kikuchi.

At least 559 records · Page 31Linked to original sources
PubMed1991

Inhibition of human ovarian cancer cell proliferation in vitro by ginsenoside Rh2 and adjuvant effects to cisplatin in vivo.

In vitro and in vivo effects of ginsenoside Rh2 on human ovarian tumor growth were examined by using a cell line (HRA) derived from ascites of a patient with serous cystadenocarcinoma of the ovary. The HRA cell proliferation in vitro was inhibited in a dose-dependent manner with dosages of 10-100 microM of ginsenoside RH2. DNA, RNA and protein synthesis by the HRA cells was inhibited in a dose-dependent manner at more than 15 microM of ginsenoside RH2. However, the growth of HRA cells transplanted in nude mice was not significantly inhibited by ginsenoside RH2. On the contrary, when cisplatin was administered together with 10 microM (but not 1 microM or 100 microM) ginsenoside RH2, the tumor growth was significantly inhibited 31 days after inoculation and the survival was also significantly prolonged, compared with not only the untreated group but also the groups given cisplatin alone or ginsenoside RH2 alone. This indicates synergistic effects between cisplatin and ginsenoside RH2. From monitoring of body weight and hematocrit, concentrations of ginsenoside RH2 used in this study did not seem to cause any adverse effect.

Animals↗
PubMed1991

[A case of human-immunodeficiency virus infection related Mycobacterium tuberculosis with atypical clinical features].

Increasing rates of human immunodeficiency virus (HIV) related tuberculosis have been noted and recently the clinical importance of the disease has been mentioned. The diagnosis of tuberculosis is more difficult in those patients with HIV seropositive than those with seronegative, because those with seropositive have atypical clinical features. A 29-year-old male, who was infected with HIV heterosexually in Central Africa in 1986, was admitted to our hospital with a history of general malaise and weight loss in April, 1989. Laboratory and physical examinations revealed anemia, thrombocytopenia, the elevation of LDH, and giant intraabdominal lymphadenopathies, suspecting malignant lymphoma. Mycobacterium was isolated from the sputa in April and was confirmed as M. tuberculosis using a DNA probe in May, 1989. Clinical symptoms including giant lymphadenopathies and laboratory abnormalities improved with antituberculosis therapy. Development of a rapid method for the diagnosis of tuberculosis was warranted in this case.

AIDS-Related Complex↗
PubMed1991

Cerebral infarction: early detection by means of contrast-enhanced cerebral arteries at MR imaging.

The authors describe a new magnetic resonance (MR) imaging sign of acute cerebral ischemia/infarction. Abnormally contrast material-enhanced curvilinear structures were demonstrated in eight patients in the evolving area of cerebral ischemia/infarction within 26 hours after the ictus on contrast-enhanced, high-field-strength (1.5-T), T1-weighted spin-echo images. The abnormal enhancement is considered to represent cortical arterial vessels of markedly slowed circulation in areas of underlying brain injury, which will eventually progress to frank brain infarction. This was demonstrated at computed tomographic (CT) and follow-up MR examinations. Characteristically, the degree of the contrast enhancement of vessels appeared most intense in the proximal portions, and the intensity of enhancement gradually diminished in the more distal portions of these vessels as they pass over the convexities and finally disappear.

Acute Disease↗
PubMed1991

Dynamic behavior of excised dog rib cage: dependence on muscle.

To assess the contribution of the rib cage to chest wall elastance and hysteresis, we measured force-displacement behavior of the isolated canine rib cage during sinusoidal forcing of the sternum in the midsagittal plane at low frequencies (0.02-2.0 Hz). Elastance of the rib cage was nearly invariant with frequency of forcing from 0.02 to 1.0 Hz and decreased with increasing amplitude. Hysteresis, the width of the force-displacement loop at middisplacement (zero displacement), was nearly constant with frequency below 1.0 Hz and increased with increasing amplitude of forcing. Removal of muscle reduced elastance and hysteresis of the rib cage substantially. The data suggest that the excised dog rib cage shows dynamic behavior similar to that of the intact human rib cage and chest wall and that respiratory muscle is responsible for a major part of the behavior of the passive chest wall. We also calculated the major and minor stiffnesses in the sagittal plane, which differed by a factor of 3-11, and their directions lay close to the dorsoventral and cephalocaudal axes, respectively. Removal of muscle reduced the stiffnesses but did not change their directions. Thus, although respiratory muscles impede motion in the sagittal plane, they do not alter its pattern.

Animals↗
PubMed1991

Inhomogeneous response of expiratory muscle activity to cold block of the ventral medullary surface.

We assessed the effects of cooling the ventral medullary surface (VMS) on the activity of chest wall and abdominal expiratory muscles in eight anesthetized artificially ventilated dogs after vagotomy and denervation of the carotid sinus nerves. Electromyograms (EMGs) of the triangularis sterni, internal intercostal, abdominal external oblique, abdominal internal oblique, and transversus abdominis muscles were measured with EMG of the diaphragm as an index of inspiratory activity. Bilateral localized cooling (2 x 2 mm) in the thermosensitive intermediate part of the VMS produced temperature-dependent reduction in the EMG of diaphragm and abdominal muscles. The rib cage expiratory EMGs were little affected at 25 degrees C; their amplitudes decreased at lower VMS temperatures (less than 20 degrees C) but by significantly fewer degrees than the diaphragmatic and abdominal expiratory EMGs at a constant VMS temperature. With moderate to severe cooling (less than 20 degrees C) diaphragmatic EMG disappeared, but rib cage expiratory EMGs became tonic and resumed a phasic pattern shortly before the recovery of diaphragmatic EMG during rewarming of the VMS. These results indicate that the effects of cooling the VMS differ between the activity of rib cage and abdominal expiratory muscles. This variability may be due to inhomogeneous inputs from the VMS to expiratory motoneurons or to a different responsiveness of various expiratory motoneurons to the same input either from the VMS or the inspiratory neurons.

Animals↗
PubMed1991

Decrease in functional residual capacity during inspiratory loading and the sensation of dyspnea.

The purposes of the present study were to determine the changes in functional residual capacity (FRC) during inspiratory loading and to examine their mechanisms. We studied seven normal subjects seated in a body plethysmograph. In both graded inspiratory elastic (35, 48, and 68 cmH2O/l) and resistive (21, 86, and 192 cmH2O.l-1.s) loading, FRC invariably decreased from control FRC and phasic expiratory activity increased. The reduction in FRC was greater with greater loads. A single inspiratory effort against an inspiratory occlusion at three different target mouth pressures (-25, -50, and -75 cmH2O) and durations (1, 2, and 5 s) also resulted in a decrease in FRC with an increase in expiratory electromyogram activity in the following expiration. The decrease in FRC was greater with greater target pressure and duration. This decrease in FRC is qualitatively similar to that during inspiratory loaded breathing, and we suspect that the same mechanisms are at work. Because neither vagal nor chemoreceptor reflex can account for these responses, we suspect conscious awareness of breathing or behavioral control to be responsible. In an additional study, the sensation of discomfort of breathing during elastic loading decreased with a decrease in FRC. These results suggest that the reduced FRC may be due to behavioral control of breathing to reduce the sensation of dyspnea during inspiratory loading.

Adult↗
PubMed1991

Effects of bronchoconstriction and external resistive loading on the sensation of dyspnea.

To determine whether the intensity of dyspnea at a given level of respiratory motor output differs between bronchoconstriction and the presence of an external resistance, we compared the sensation of difficulty in breathing during isocapnic voluntary hyperventilation in six normal subjects. An external resistance of 1.9 cmH2O.1-1.s was applied during both inspiration and expiration. To induce bronchoconstriction, histamine aerosol (5 mg/ml) was inhaled until airway resistance (Raw) increased to a level approximately equal to the subject's control Raw plus the added external resistance. To clarify the role of vagal afferents on the genesis of dyspnea during both forms of obstruction to airflow, the effect of airway anesthesia by lidocaine aerosol inhalation was also examined after histamine and during external resistive loading. The sensation of difficulty in breathing was rated at 30-s intervals on a visual analog scale during isocapnic voluntary hyperpnea, in which the subjects were asked to copy an oscilloscope volume trace obtained previously during progressive hypercapnia. Histamine inhalation significantly increased the intensity of the dyspneic sensation over the equivalent external resistive load at the same levels of ventilation and occlusion pressure during voluntary hyperpnea. Inhaled lidocaine decreased the sensation of dyspnea during bronchoconstriction with no change in Raw, but it did not significantly change the sensation during external resistive loading. These results suggest that afferent vagal activity plays a role in the genesis of dyspnea during bronchoconstriction.

Adult↗
PubMed1991

Electron-microscopic observations of the alveolar brush cell of the rat.

The alveolar brush cells in the rat lung were observed by transmission electron microscopy. The general structural features of the brush cells in this report were basically in agreement with earlier descriptions. However, this report is the first to detect long, thick microvilli with a unique form protruding into the alveolar lumen in parallel with the basement membrane, not vertically to the basement membrane. Moreover, intranuclear inclusions in the nucleus were observed for the first time in the alveolar brush cells in this study.

Animals↗
PubMed1991

Total lactate dehydrogenase and its isozymes in serum from patients with primary carcinoma of the ovary.

Serum lactate dehydrogenase (LDH), its isozymes and alpha-hydroxybutyrate dehydrogenase (HBD) were examined in 57 patients with primary carcinoma of the ovary and compared to those in 220 patients with benign ovarian tumor. Serum LDH, LDH-4, LDH-5 and HBD in patients with ovarian carcinoma were significantly higher than those in patients with benign ovarian tumor. Except for the percent fraction of LDH-5, LDH activity, LDH-4 activity, percent fraction of LDH-4, LDH-5 activity and HBD activity in patients with ovarian carcinoma correlated significantly with stage of disease. The positive result of ovarian carcinoma was highest at LDH-4 activity (43.6%), followed by LDH activity (42.1%), HBD activity (34.6%), LDH-5 activity (32.7%), percent fractions of LDH-4 and LDH-5 (20.0%). On the other hand, the false-positive rate in patients with benign ovarian tumor was highest at LDH activity (12.7%), followed by HBD activity (10.0%), LDH-5 activity (8.6%), percent fraction of LDH-5 (8.2%), LDH-4 activity (6.8%) and percent fraction LDH-4 (3.6%). The detection rate for early ovarian carcinoma (stages I and II) was elevated from 4.5% by HBD activity alone to 50.0% by a combination assay of LDH, LDH-4, LDH-5 and HBD, while that for advanced ovarian carcinoma (stages III and IV) was elevated from 50.0% by HBD alone to 79.4% by the combination assay.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenocarcinoma↗
PubMed1991

Role of hypoxic drive in regulation of postapneic ventilation during sleep in patients with obstructive sleep apnea.

To elucidate the role of chemoresponsiveness in determining postapneic ventilation in sleep-disordered periodic breathing, we measured ventilatory response associated with apnea-induced arterial oxygen desaturation during sleep and compared it with the awake hypoxic ventilatory response (HVR) in 12 male patients with obstructive sleep apnea (OSA). Awake HVR was measured at a slight hypocapnic level (end-tidal PCO2 = 37 +/- 1 mm Hg, mean +/- SEM), and separately at a PCO2 of 45 mm Hg. During non-REM sleep both the ventilatory rate (VE) and the average respiratory frequency (f) in the ventilatory phase between apneic episodes were inversely correlated with the nadir of arterial oxygen saturation (nSaO2) produced by the preceding apneic phase in all patients (VE versus nSaO2; r = -0.74 +/- 0.03, mean +/- SEM; f versus nSaO2, r = -0.56 +/- 0.04). The average tidal volume (VT) also was correlated with nSaO2 in 10 of the patients (r = -0.56 +/- 0.05). During REM sleep VE was correlated with nSaO2 in 11 patients (r = -0.75 +/- 0.03, p less than 0.02). The response of VE to nSaO2 (delta VE/delta nSaO2) varied widely among the patients (non-REM, 0.52 to 2.16; REM, 0.29 to 1.44 L/min/%) and was significantly lower during REM than non-REM sleep (p less than 0.01). The value of delta VE/delta nSaO2 during both non-REM and REM sleep was correlated with awake HVR at an end-tidal PCO2 of 45 mm Hg (non-REM, r = 0.83, p less than 0.02; REM, r = 0.76, p less than 0.05) but not with that at the hypocapnic level.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

Silent obstruction of the coronary stenosis between diagnostic angiography and later percutaneous transluminal coronary angioplasty without myocardial infarction.

Among 204 patients with severe coronary artery stenosis amenable to percutaneous transluminal coronary angioplasty (PTCA), 5 (2.5%) developed new silent total coronary occlusion of the vessel to be dilated without any chest symptom during the period between diagnostic coronary angiography and repeat coronary angiography at the time of the operation. We evaluated the clinical and angiographical characteristics of the patients with silent obstruction of the coronary artery in a short time, compared with the patients with unstable angina pectoris, who is considered to be suffering from acute myocardial infarction with severe chest symptom. None of the clinical variables studied showed a significant difference between the two groups. Among the angiographic variables, the degree of collateral was higher and impaired coronary perfusion distal to the lesion was more frequently found in unstable angina group. These results suggest that unstable angina is in a later stage of the ischemic heart disease compared with the time of the diagnostic angiography in patients with silent obstruction. Silent obstruction of high degree coronary stenosis is presumably due to the development of collateral circulation.

Aged↗
PubMed1991

Effects of elastic loading and exercise on pulmonary gas exchange in dogs.

We assessed the effects of negative intrathoracic pressure induced by inspiratory elastic loading on pulmonary, gas exchange with and without electrically induced hindlimb exercise in 8 normal, anesthetized dogs. Two elastic loads (EL) were used; one of 81 and one of 140 cmH2O/liter. These are equivalent to doubling and tripling the normal elastance of the dog's respiratory system, respectively. Elastic loading decreased ventilation and caused hypoxemia and hypercapnia, but it did not affect systemic arterial pressure or heart rate. During exercise, increase in ventilation was limited, whereas increase in cardiac output was not affected by elastic loading. Alveolar-arterial O2 tension difference (A-aDO2) was not changed significantly by exercise alone. However, elastic loading accompanied by exercise increased A-aDO2. Although comparable end-inspiratory pleural pressure was achieved with large EL (-29 +/- 2 cmH2O, mean +/- SE) and small EL with exercise (-30 +/- 2 cmH2O), the latter increased A-aDO2 whereas the former did not. Large negative intrapleural pressure combined with increased cardiac output may have caused transient interstitial edema.

Animals↗
PubMed1991

The stimulatory effect of PACAP 38 on amylase release in dispersed rat pancreatic acini.

Pituitary adenylate cyclase activating polypeptide 38 (PACAP 38), a novel peptide of the vasoactive intestinal polypeptide (VIP) family, was shown to stimulate enzyme secretion in the dispersed rat pancreatic acini. The dose-response of pancreatic enzyme secretion to PACAP 38 was nearly identical with that to VIP. In the presence of a submaximal dose of PACAP 38 (1 nM), amylase release stimulated by an agonist working via the elevation of intracellular cyclic AMP (VIP, dibutyryl cAMP) was additionally responded, but the amylase release stimulated by an agonist via the elevation of cytosolic free calcium (carbachol, cholecystokinin) was potentiated synergistically. The present data suggest that PACAP 38 is a new candidate for the cAMP-mediated stimulant of pancreatic exocrine secretion.

Amylases↗
PubMed1991

Islet amyloid polypeptide has no effect on amylase release from rat pancreatic acini stimulated by CCK-8, secretin, carbachol and VIP.

Islet amyloid polypeptide (IAPP), a novel peptide recently isolated from the amyloid substance of pancreatic islets, has been localized in normal islet B cell granules, suggesting its physiological action in exocrine pancreatic function. In the present study, the direct effect of IAPP on secretagogue-stimulated pancreatic enzyme secretion was investigated using dispersed rat pancreatic acini. Various concentrations of IAPP (10(-5) -10(-10) M) showed no significant influence on amylase release stimulated either by submaximal doses of CCK-8 (10(-11) M), secretin (0.5 x 10(-6) M) or carbachol (10(-6) M), or by a maximal dose of vasoactive intestinal peptide (10(-8) M). These results may provide negative evidence for a physiological significance of IAPP in rat pancreatic enzyme secretion.

Amylases↗
PubMed1991

Deformability of mammalian and fish erythrocytes: comparison of mean pore transit times of cells and estimation of cellular viscosity and elasticity.

Red blood cells (RBCs) of various species of mammals and fish were subjected to a modified Nuclepore filtration test, which determines average time required for cells to pass through filter pores under constant suction. The values so far obtained, when plotted against the ratio of mean cell diameter to pore diameter, fall in a region given by a formula, which has been derived from a simple viscoelastic model for the deformation of a cell, for a small range of cellular viscosity (1.0-2.0 x 10(3) dyn.s/cm for mammals at 37 degrees C, 3.0-5.0 x 10(-3) dyn.s/cm for fish at 15 degrees C). Furthermore, estimates of cellular elasticity given from pore transit times at the cell-pore diameter ratio beyond 2.0 also fall in a similar range (0.5-1.0 dyn/cm) for both the mammalian and fish cells. It is thus suggested that RBC filterability may not differ greatly, when compared at a comparative temperature, between different species studied so far, including mammals and fish, for a relatively large range of the extent to which cells are caused to deform. A question then arises about the shape and cytoplasm factors which have been accepted as the primary determinants of RBC deformability.

Animals↗
PubMed1991

Development of the total artificial heart control system.

Sympathetic neurogram is potentially useful for the real time total artificial heart (TAH) control system. In this study, we used sympathetic tone and hemodynamic derivatives to prospect the following cardiac output in acute animal experiments using adult mongrel dogs. Moving averages of the mean left atrial pressure and mean aortic pressure were used as the parameters of the preload and afterload, respectively. Renal sympathetic nerve activity (RSNA) was also utilized as the parameter of the sympathetic tone. Equation which prospect the following cardiac output was calculated using the multiple linear regression analysis of the time series data in adult mongrel dogs. A significant correlation was observed between the prospective and following measured cardiac output. These results suggest the potential usefulness of the sympathetic neurogram for the real time TAH automatic control system.

Animals↗