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Biomedical subjects

M Aoki

Publications and source records attributed to M Aoki.

At least 559 records · Page 31Linked to original sources
PubMed1993

Relationship between vitamin K dependent coagulation factors and anticoagulants (protein C and protein S) in neonatal vitamin K deficiency.

To determine the relationship between vitamin K dependent coagulation factors and natural anticoagulants, namely protein C and protein S, in various degrees of vitamin K deficiency, plasma values for clotting activity, protein induced by vitamin K absence (PIVKA-II), protein C antigen, gamma-carboxy protein C antigen, and protein S antigen including total and free fractions and activity of protein C were measured in 66 full term and healthy breast fed neonates who did not receive vitamin K supplement at birth. The 66 neonates were divided into a control group (17 cases) and a low group (49 cases) according to their values for clotting activity--that is, > or = 20% or < 20% during the first six days of life--and vitamin K was immediately given when the neonates showed values < 20%. In the low group clotting activity gamma-carboxy protein C, free protein S, and protein C activity was significantly decreased to a minimum on day 2 or 3, and increased in parallel after vitamin K administration. Furthermore, they were positively correlated with one another and inversely cor-correlated with the PIVKA-II concentrations. These findings suggest that simultaneous gamma-carboxylation of coagulation factors and proteins C and S acts to maintain both coagulation and anticoagulation activities in parallel at various concentrations of vitamin K. The breast milk intake in the group with low values of clotting activity was significantly lower than that in the control group during the first three days of life.(ABSTRACT TRUNCATED AT 250 WORDS)

Biomarkers↗
PubMed1993

The inhibitory effects of positive end-expiratory pressure (PEEP) on phrenic motoneuronal activity in cats.

We examined the effects of positive end-expiratory pressure (PEEP) on phrenic single motoneuronal activity (SMA) in anesthetized, paralyzed, and mechanically ventilated cats. SMA was isolated and recorded from the right C-5 phrenic root. Phrenic nerve compound activity was also recorded simultaneously from the contralateral C-5 phrenic root in each preparation. With the vagus nerve intact, phrenic SMA significantly decreased to 91.5, 76.2, 45.3, and 21.6% of control when PEEP was loaded to levels of 2.5, 5, 7.5, and 10 cm H2O, respectively. Compound activity also decreased. Moreover, not only phrenic single postinspiratory inspiratory activity (PIIA) but also the ratio of PIIA to the inspiratory SMA significantly decreased with increments of PEEP. In contrast, with the vagus nerve sectioned, phrenic nerve activity, including PIIA, remained unchanged when loading PEEP. These results suggest that 1) SMA might be inhibited in lung volume-dependent manner by PEEP, and that 2) the vagal nerve afferents are essential for the inhibition of SMA by PEEP.

Action Potentials↗
PubMed1993

Synthetic Arg-Gly-Asp-Ser analogues of the cell recognition site of fibronectin that retain antimetastatic and anti-cell adhesive properties.

Synthetic peptide analogues of the Arg-Gly-Asp-Ser (RGDS) sequence of fibronectin in which the amino acid of Gly was substituted with another one, named X, i.e. Arg-X-Asp-Ser (R-X-DS), and N-terminal modified R-X-DS have been synthesized to examine their antimetastatic effects in murine lung or liver metastasis models, as well as the inhibitory effect on tumor cell invasion, migration and adhesion in vitro. R-X-DS [X = Leu (L) or D-Leu (1)], as well as RGDS at a high dose of 3000 micrograms, significantly reduced the number of lung tumor colonies when they were co-injected with B16-BL6 melanoma. At a dose of 1000 micrograms/mouse, N-terminal modified R-X-DS, i.e. acetyl-D-R-X-DS [AcDR-X-DS: X = G, L or I], showed a more potent inhibitory effect on the lung or liver metastasis of B16-BL6 melanoma or L5178Y-ML25 lymphoma cells, respectively, as compared with RGDS or R-X-DS. AcDRLDS and AcDRIDS prevented the invasion of B16-BL6 cells into Matrigel/fibronectin- and Matrigel/laminin- coated filters, haptotactic migration, and the adhesion of the cells to both fibronectin- and laminin-coated substrates, whereas AcDRGDS inhibited only fibronectin-mediated cell functions. The intermittent i.v. administration of a water soluble vinylpolymer [poly(carboxyethylmethacrylamide), poly(CEMA)] containing R-X-DS (X = L or 1) or RGDS, following the subcutaneous inoculation of B16-BL6 cells, significantly inhibited spontaneous Jung metastasis as compared with multiple administrations of RGDS, R-X-DS or the untreated control.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1993

Effect of calyculin-A, phosphatase inhibitor, on 20 alpha-hydroxysteroid dehydrogenase activity in rat luteal cell culture.

The effects of calyculin-A (CL-A), a phosphatase inhibitor, on 20 alpha-hydroxysteroid dehydrogenase (20 alpha-HSD) activity were studied in rat luteal cell cultures to examine whether protein phosphatases were involved in the regulation of the enzyme activity. Luteal cells were harvested from the rats on day 6 of pseudopregnancy. In the absence of prolactin (PRL), the stimulatory effect of CL-A (10(-9) M) on 20 alpha-HSD activity was observed during the first 3 h period of the culture, but was not discernible thereafter. Since the enzyme activity of luteal cells during pseudopregnancy is known to be suppressed by PRL, the results suggest that this effect of CL-A could be manifested only as long as the effect of endogenous PRL was remained. On the other hand, CL-A enhanced the 20 alpha-HSD activity of the cells cultured for 24 h, where a spontaneous increase in 20 alpha-HSD activity was blocked by exogenously supplementing the culture medium with PRL. These results suggest that a CL-A sensitive phosphatase(s) may be involved in the action of PRL in suppressing the increase in 20 alpha-HSD activity in rat luteal cells.

20-Hydroxysteroid Dehydrogenases↗
PubMed1993

In vivo profile of myocardial energy metabolism of pressure-overloaded rat.

Cardiac energy metabolism of pressure-overloaded rat hearts was examined under in vivo and in vitro conditions. Two, 4 and 6 weeks after constriction of the abdominal artery, the hemodynamic and metabolic profiles of hearts in vivo and of perfused hearts were determined. Significant increases in left ventricular weight/body weight (30 to 45% increase relative to the sham group), systolic and diastolic blood pressure (22 to 33% increase) and pressure-rate product (31 to 33% increase) were observed 2, 4 and 6 weeks after the operation, and a slight but significant decrease in heart rate was observed at 2 weeks after the operation. Tissue hydroxyproline content increased (17 to 93%) with time after pressure-overload. These findings are indicators of pressure-overloaded cardiac hypertrophy. The total high-energy phosphates of the in vivo rat myocardium under artificial respiration were lower than those of sham-operated rat myocardium 2 (23%) and 4 weeks (21%), but not 6 weeks after aortic constriction. The maximal oxygen consumption rates of mitochondria, when determined in the skinned cardiac fibers, also decreased 2 (47%) and 4 weeks (36%), but reversed 6 weeks after pressure-overload. However, the myocardial ATP, a utilizing form of high-energy phosphate, of pressure-overloaded rat myocardium remained normal at all times after cardiac hypertrophy. This suggests that alterations in hemodynamic variables of in vivo pressure-overloaded rats may not be attributable to a reduction in the myocardial energy production. In the perfused hearts isolated from pressure-overloaded rats, tissue ATP levels were similar to those of sham-operated rats, although the tissue creatine phosphate tended to be reduced in the pressure-overloaded animals at all stages of cardiac hypertrophy examined. Only a marginal decrease in the tissue high-energy phosphate (13%) was observed 4 weeks after the operation relative to that of sham-operated rats. In contrast, the developed tension of the perfused pressure-overloaded rat hearts was consistently lower (27 to 36%) than that of the sham-operated rat hearts. The results suggest that the high-energy phosphate levels of pressure-overloaded rat myocardium in vitro are unlikely to account for the observed decline in cardiac contractile function. The reduction of myocardial high-energy phosphates of pressure overloaded rats may be due to an adaptative change rather than a causal events.

Adenosine Triphosphate↗
PubMed1993

Chronic aortic dissection complicated by recurrent obstructive pneumonia.

A 68-year-old man with aortic aneurysm who had repeated episodes of obstructive bronchopneumonia is reported. Serial chest X-rays revealed infiltrative shadows in the left lower lung field. A thoracic computed tomogram demonstrated a dissecting descending aorta compressing the left lower bronchi and abnormal shadows, probably inflammatory, distal to the obstructions. Because of signs of impending rupture of the dissected aorta, surgical repair was performed and there has been no recurrence of respiratory infection since.

Aged↗
PubMed1993

[Comparison of the gold wire electrode with cotton wick electrode for electroretinography in small laboratory animals].

Using the gold wire and cotton wick electrodes, the electroretinograms of mice and rats were measured, and then they were compared. The results obtained were as follows: 1) There were no remarkable differences in the latencies and amplitudes of a- and b-waves, amplitudes and numbers of waves of oscillatories between two different electrodes. 2) It was easy to make and maintain the gold wire electrode as compared with the cotton wick electrode. From these results, it appears that the gold wire electrode is useful for measuring the electroretinogram of small laboratory animals.

Animals↗
PubMed1993

[Possibility of detecting visual functional disturbance in rats by the open-field test].

In order to determine whether visual disturbance in small rodents is detectable by means of the open-field test, the ambulation scores of enucleated and intact rats in an open-field were measured. In a 30-min test of Slc:Wistar/ST rats, there were significant differences in ambulation scores between enucleated and intact rats in the first 10-min. In addition, the effects of observation times (09:00-11:00, 13:00-15:00 and 17:00-19:00 hr) and strains on the open-field test were studied using a 10-min test. Regardless of observation times, ambulation scores of enucleated rats of the Slc:Wistar/ST and F344/N Slc strains were significantly elevated as compared with those of intact rats from both strains. When tested during the 13:00-15:00 hr period, there were significant differences in the Slc:SD rats. These findings indicate that the changes in ambulation are due to visual disturbance. However, significant ambulatory changes in F344/N Slc rats were documented at the three different observation times. Based on these results, Slc:Wistar/ST rats appear to be suitable for detecting visual disturbance by the open-field test.

Animals↗
PubMed1993

[Visual evoked potential from dura in rats].

Visual evoked potentials (VEPs) were recorded from 8 different points (from points A and B near the bregma to points G and H near the occipital bone) of the dura under parietal bone in rats. The study was performed with 68 adult male Slc: Wistar/ST rats weighing 259.9-298.0g. VEPs recorded from the dura had a large negative component with a peak around 45 msec (N1), a large positive component with a peak around 75 msec and a large negative component with a peak around 120 msec (N2). Points A and B were not suitable for recording of the VEPs because some rats showed no N2 peak. The amplitude of peaks N1 to P at point E, upper the left optic layer of the superior colliculus, was higher than those from other points. Point E was the best position for recording of the VEP from dura in Slc: Wistar/ST rats.

Animals↗
PubMed1993

[Age-related changes in the visual function of WBN/Kob rats: a behavioral study].

Changes in visual function with increasing age were studied in male WBN/Kob rats, a new diabetic strain. In order to detect visual abnormalities in WBN/Kob rats, 5 WBN/Kob and 5 Wistar/ST (control) rats from each group were examined at 5, 9, 13, 17, 23, 27, 36, 45, 54, 67 and 80 weeks of age using dark and light distinction and open-field tests. The rates at which WBN/Kob rats selected the dark area were 85.0 to 100%, 58.8% and 52.6% at 5 to 54, 67 and 80 weeks of age, respectively, while those for Wistar/ST rats were 85.0 to 100% in each age group. Visual abnormality was obvious in WBN/Kob rats aged 67 and 80 weeks, compared with Wistar/ST rats (P < 0.05). There were no significant signs of visual abnormality in the open-field test. Detection of visual abnormality seems to be possible from 67 weeks of age.

Aging↗
PubMed1993

BU-4794F, a new beta-1,3-glucan synthase inhibitor.

New beta-1,3-glucan synthase inhibitor (BU-4794F) was isolated from the culture broth of Gilmaniella sp. FA4459. Structural studies indicated that it was a novel member of the papulacandin group of antibiotics.

Antifungal Agents↗
PubMed1993

[Present world status and problems resolved in lung transplantation: from the surgical view].

We have summarized the results of international data from many institutes. In 1983 in Toronto, Canada, Cooper performed that first successful clinical case lung-transplantation. Subsequently, there have been more than 1,500 cases of lung transplantation. One reason for Cooper's success was the use of cyclosporin, the other was the performing of omentopexy. Among the total lung transplant cases, single lung transplant comprised 66%, bilateral sequential lung transplant comprised 26%, and en-blocdouble lung-transplant, (8%). Of the 1,540 recipients, the most common underlying of sease was emphysema (360 cases), followed by fibrosis (289 cases), cystic fibrosis (206 cases), alpha-1 antitripsin deficiency (210 cases) and rare diseases including pulmonary hypertension, lymphagiomyomatosis and sarcoidosis. The survival rate of all patients was 68% at 1 year, and 60% at two years.

Adolescent↗
PubMed1993

Nitroglycerin improves functional recovery of neonatal lamb hearts after 2 hours of cold ischemia.

BACKGROUND: Vascular events during initial reperfusion after a period of hypothermic cardioplegic ischemia may play an important role in the recovery of mechanical function. Prior studies have shown (1) that dysfunction of the postischemic myocardium after normothermic ischemia can be ameliorated by vasodilation and (2) that endothelial dysfunction in the coronary bed and mechanical dysfunction were correlated after hypothermic ischemia. The present study was undertaken to further explore the relation between vascular events during reperfusion and the recovery of mechanical function after hypothermic ischemia by the infusion of the endothelium-independent vasodilator nitroglycerin during reperfusion. METHODS AND RESULTS: We assessed the effect of an infusion of nitroglycerin on the recovery of isolated blood-perfused neonatal lamb hearts arrested for 2 hours with 15 degrees C K+ cardioplegic solution, comparing 8 hearts receiving a nitroglycerin infusion with 9 control hearts. After 30 minutes of reperfusion, nitroglycerin-infused hearts compared with control hearts had better percent recovery of maximum left ventricular developed pressure (83.5 +/- 8.1% vs 73.6 +/- 8.9%, mean +/- SD), left ventricular dP/dt (77.2 +/- 7.7% vs 67.4 +/- 10.3%), coronary blood flow (141.2 +/- 30.6% vs 84.4 +/- 10.4%), and myocardial oxygen consumption (100.7 +/- 51.3% vs 71.2 +/- 18.6%), (all except myocardial oxygen consumption with P < .05). In each heart, we also tested the coronary vascular resistance response to 10(-6) mol/L acetylcholine infusion to assess endothelial function. The recovery of the coronary vascular resistance response to acetylcholine was reduced after reperfusion in both groups compared with the preischemic response to acetylcholine (nitroglycerin, 14.9 +/- 53.8%; control, 13.4 +/- 38.3%). CONCLUSIONS: These results suggest that the effects of hypothermia and reperfusion on recovery of mechanical function after hypothermic ischemia can be offset by an infusion of nitroglycerin. Vasospasm secondary to endothelial dysfunction may play an important role in cardiac recovery after hypothermic ischemia.

Animals↗
PubMed1993

Effects of adenosine infusion during reperfusion after cold cardioplegic ischemia in neonatal lambs.

BACKGROUND: Postischemic infusion of adenosine (Ado) has been postulated to reduce reperfusion injury after normothermic ischemia, but the effect of Ado after hypothermic ischemia is unknown. METHODS AND RESULTS: We infused Ado (350 mumol/L), Ado + Ado antagonist theophylline (Ado + T, 7 mmol/L), A1 agonist cyclohexyl-Ado (0.25 mumol/L), A2 agonist cyclopropyl carboxamide Ado (0.25 mumol/L), or blood alone (group C) during the first 20 minutes of reperfusion after 2 hours of cold cardioplegic ischemia using an isolated, blood-perfused neonatal lamb heart model (n = 8 in each group). At 30 minutes of reperfusion, left ventricular (LV) maximum developed pressure (DP), dP/dt, -dP/dt, maximum DP at V10 (volume that gives LVEDP of 10 mm Hg at baseline measurement), dP/dt at V10, and LV stiffness constant (KA) at V10 were measured. Coronary blood flow and oxygen consumption (MVO2) were also measured to evaluate the metabolic recovery. Groups Ado, A1, and A2 showed better functional recovery than group C (DP for group C, 74.6 +/- 5.60%; group Ado, 94.2 +/- 10.7%; group A1, 89.3 +/- 4.40%; group A2, 86.7 +/- 9.00%; P < .01), but theophylline offset the Ado effect (Ado + T, 74.6 +/- 6.4%). Coronary blood flow was higher in groups Ado + T and A2 than group C (group C, 156.7 +/- 45.7%; group Ado + T, 238.0 +/- 41.0%; group A2, 258.6 +/- 70.3%; P < .05). MVO2 was higher in groups Ado, Ado + T, A1, and A2 than group C (group C, 57.7 +/- 11.0%; group Ado, 91.5 +/- 20.1%; group Ado + T, 210.7 +/- 60.0%; group A1, 82.8 +/- 31.9%; group A2, 83.5 +/- 12.8%; P < .05). CONCLUSIONS: Ado infusion improved recovery of mechanical function after hypothermic ischemia, and its beneficial effect appears to involve both A1 and A2 receptors. Since group Ado + T had high coronary blood flow but not improved systolic function and group A1 had low coronary blood flow and improved systolic function, coronary vasodilation alone is not responsible for this beneficial effect. Ado may be a useful agent after hypothermic ischemia in the immature heart, although the precise mechanisms remain unclear.

Adenosine↗
PubMed1993

[Non-Hodgkin's T cell lymphoma associated with marked eosinophilia].

A case of non-Hodgkin's T cell lymphoma (diffuse lymphoma, large cell type) associated with marked eosinophilia and pleurisy in a 57-year-old male is reported. The leukocyte count was 12.5 x 10(3)/microliters and eosinophil count was 53% and the absolute count of 6.6 x 10(3)/microliters. The patient's serum and pleural effusion fluid, containing abundant lymphoma cells, showed eosinophil colony stimulating factor (Eo-CSF) activity. Conditioned medium (CM) prepared from patient's T cells (T-CM) produced Eo-CSF and this was enhanced by interleukin-2 (IL-2) stimulation. We demonstrated that the patient's serum contained a significant amount of interleukin-5 (IL-5) and the patient's T-CM, particularly after IL-2 stimulation contained a significant amount of granulocyte-macrophage colony-stimulating factor (GM-CSF). These findings suggest that Eo-CSF produced by neoplastic T cells or normal T cells activated by tumor antigen stimulated the production of eosinophils in this patient and that both IL-5 and GM-CSF might play a role in Eo-CSF activity.

Eosinophilia↗
PubMed1993

[Photodynamic therapy (PDT) in roentgenographically occult lung cancer by photofrin II and excimer dye laser].

UNLABELLED: Patients (pts) with hilar type early lung cancer from 5 hospitals served as the subjects to assess the complete response rate and toxicity of PDT with Photofrin II (PHE) and excimer dye laser (PDT EDL-1). ENTRY CRITERIA: 1. Histologically proven lung cancer with endoscopically superficial thickening or small protrusion. 2. All lesions that were located proximally from the subsegmental bronchus, were visible to the distal margin of the lesions. 3. N0M0. METHOD: All pts received PHE (2 mg/kg) i.v., 48 hours before PDT. Tumor lesions superficially photoradiated by an excimer dye laser via flexible bronchoscope. RESULTS: From September 1990 to March 1992, 39 pts with 46 carcinomas (CA) were enrolled. Thirty-three pts with 40 CA were evaluable. 1. RESPONSE: Thirty-five in 40 CA showed a complete response (CR) (87.5%, 95% confidence limit: 73.2-95.8%). All 32 cases of CA equal to or less than 1 cm of tumor length were CR, but 3 CA relapsed locally. Thirty-three of 35 CA visible to the distal margin were CR (91.7%, 95% confidence limit: 77.5-98.3%). 2. Toxicity (> WHO grade 2): Three pts (7.7%) had transient dermatitis and sunburn, while another pt (2.6%) had symptoms due to obstructive pneumonitis. CONCLUSIONS: Tumors equal to or less than 1 cm in length and visible to the distal margin are curable by PDT.

Aged↗