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Biomedical subjects

K Osada

Publications and source records attributed to K Osada.

At least 73 records · Page 4Linked to original sources
PubMed1993

Effects of microbial products on glucose consumption and morphology of macrophages.

We studied the effects of microbial products on glucose consumption and morphology of macrophages which were elicited with thioglycollate medium. Macromolecules such as lipopolysaccharide (LPS), tumor promoters, and respiratory inhibitors increased macrophage glucose consumption without inducing evident morphological changes. The assay system was used to screen for active substances in culture broth extracts from actinomycetes. Among them, aureothin increased glucose consumption of macrophages and inhibited respiration of a rat mitochondrial fraction. Concanamycin A induced morphological changes of macrophages into needle-like shapes but not of cloned cells including the macrophage-like cells J774.1. This compound changed fibrosarcoma L929 cells into round shapes without affecting the shape of a nontransformed fibroblast, BALB/3T3 cells. Antimycin and concanamycin A increased tumor-killing activity of macrophages when added during the effector phase. These results suggest that this assay system is simple and sufficiently reproducible and thus usable for screening for modulators of macrophage function among natural products.

3T3 Cells↗
PubMed1993

An experimental study of chondrogenesis and osteogenesis in rat submandibular gland induced by implantation of demineralized dentin.

Demineralized dentin pieces were implanted in 18 rat submandibular glands to examine the chondrogenesis and osteogenesis in pleomorphic adenoma of the salivary gland. After 7 days of implantation, a large amount of cartilage tissue was found next to the inner portions of the implanted pieces, and small amounts of the osteoid and cartilage tissues were detected next to the outer portions. A small amount of bone tissue was found in contact with the cartilage 10 days after the implantation. In the inner portions, invasions of capillaries and a small amount of osteoid tissue were noted. These histological findings resembled those of endochondral ossification. Large amounts of bone tissue and resorption of the implant were observed after 14 days. It has been suggested that cartilage and bone are produced by bone morphogenetic proteins (BMP) in demineralized dentin resulting in chondrogenesis followed by osteogenesis in submandibular gland. Apparently, undifferentiated mesenchymal cells are produced by implantation, undergo dedifferentiation, and are redifferentiated into chondroblasts and osteoblasts in the presence of BMP. These results suggest that chondrogenesis and osteogenesis in the submandibular gland are induced by BMP. It is possible that the chondroid tissues in pleomorphic adenoma of the salivary glands are induced by proteins such as BMP.

Adenoma, Pleomorphic↗
PubMed1991

[Cardiac assist device with inserted alternate-drive skeletal muscle pump system].

Many studies on a skeletal muscle pump (SMP) for use as a cardiac assist device require preconditioning as a countermeasure to muscle fatigue. However, we conducted experiments in the hope of developing a cardiac assist device with an alternate-drive SMP system requiring no preconditioning. Adult mongrel dogs were used. We prepared a roll-type SMP from a pedicled muscle flap of the latissimus dorsi and major pectoris muscle, and an insert type SMP without separating the latissimus dorsi and major pectoris muscle. The muscles were stimulated at a frequency of 60 rpm at cycles of burst stimulation. Thirty-minute intermittent driving was performed. The hydrodynamic changes were measured at five-minute intervals for a total of three hours. The function of the pumps markedly declined after a few minutes of driving the roll-type SMPs but remained satisfactory after thirty minutes of driving the insert-type SMPs. Consequently, we concluded that dual SMPs, alternately driven through thirty minute intermittent drive and rest intervals, could be useful as cardiac assist devices without preconditioning.

Animals↗
PubMed1991

[A case of ruptured distal arch aneurysm associated with postoperative unilateral respiratory disorders].

This paper describes a patient with ruptured distal arch aneurysm associated with postoperative unilateral respiratory disorders whose life was able to be saved by surgery. The patient was a 68-year old male who underwent emergency surgery due to sealed rupture of distal arch aneurysm while preparing for selective surgery. Artificial graft replacement of the distal arch was carried out under centrifugal pump bypass. Respiration was controlled using differential lung ventilation (DLV) techniques. This was done because weaning from the respirator was difficult due to decreases in lung-thorax compliance on the opened chest side after surgery. Weaning from the respirator was achieved on the 10th day of illness after surgery. Postoperative prognosis of ruptured thoracic aneurysm is extremely poor, with high mortality being attributable to the fact that most patients are elderly and the incidence of respiratory and cardiovascular complications is very high. In addition, problems are often encountered in postoperative respiration management in patients with thoracic aneurysm who need open chest surgery. DLV seems to be a useful support in such patients who have underlying respiratory disorders.

Aged↗
PubMed1991

Ameloblastoma and its relationship to ameloblastic fibroma: their histogenesis based on an unusual case and review of the literature.

The present paper describes the relationship between ameloblastoma and ameloblastic fibroma deduced from a case diagnosed as "ameloblastoma combined with ameloblastic fibroma" arising in the mandible of a 5-year-old boy. Histologically, the tumor consisted of ameloblastoma in the central area and ameloblastic fibroma in the peripheral area; it clinically fits the characteristics of ameloblastic fibroma based on predominant age, manner of growth, and encapsulation. We reviewed the literature and discussed the relationship between ameloblastoma a ameloblastic fibroma in terms of tumorigenesis. It is assumed that ameloblastic fibroma can also be transformed into ameloblastoma, if the succeeding hard tissues are not formed, and the collagenous connective tissue substituting for the stromal mesenchymal tissue is formed by the inductive effect of the epithelial strands or other unknown factors. Several possibilities relative to the pathogenesis of ameloblastoma have been proposed by oral pathologists; however, to our knowledge, "ameloblastic fibroma can be transformed into ameloblastoma" has not hitherto been reported. The case we experienced here may be thought as an intermediate tumor pattern between ameloblastic fibroma and ameloblastoma.

Ameloblastoma↗
PubMed1991

[Nuclear DNA content in breast cancer in relation to postoperative recurrence].

Nuclear DNA content in breast cancer patients who underwent extended radical mastectomy was investigated to evaluate its possible relation to postoperative recurrence. The most frequent site of the first recurrence in diploid type (D type) cases was the bone and the frequency was significantly higher than that in non-diploid type (N type) cases. On the other hand, the ploidy pattern in all cases associated with local or local lymph node recurrence was N type and the lung was the next frequent site of recurrence in N type case. The frequency of over 4c cells was the highest in the cases of local or local lymph node recurrence being significantly higher than in all cases of distant recurrence or of the bone recurrence. The cumulative disease-free survival rate in patients with D type breast cancer was significantly higher than that in patients with N type. These results suggest that nuclear DNA content provides important information for deciding therapy and the schedule of postoperative follow-up study based on the mode of recurrence.

Breast Neoplasms↗
PubMed1991

[Clinical study of centrifugal pump bypass as an auxiliary technique for surgical treatment of descending thoracic aorta].

Left heart bypass or arterial bypass using a centrifugal pump (Bio-pump bypass) with a H-PSD shunt tube was performed as an auxiliary technique for the treatment of descending thoracic aorta in 13 cases. Hemodynamic differences during aortic clamp were compared between cases using Bio-pump bypass and 4 cases of axillo-femoral temporary bypass which were carried out in the first term. Furthermore, in Bio-pump bypass cases, the bypass route was investigated from the point of view of operative complications in relation to bypass technique. Peripheral blood pressure and urinary output during aortic clamp were significantly increased in the Bio-pump bypass group. Those results indicated that the Bio-pump bypass was useful as an auxiliary technique especially for high risk patients with low renal function. In particular, left heart bypass was a beneficial technique which was not affected by modality or region of disorder in the descending thoracic aorta. However, this technique should be selected carefully for patients with cardiac disease, for instance severe left ventricular hypertrophy, because two cases of operative complications consisting of pericardial effusion related to the bypass technique were experienced in this study.

Aorta, Thoracic↗
PubMed1991

[Cardiac assist device with skeletal muscle ventricle--alternate-drive twin pump system as a countermeasure to prevent skeletal muscle fatigue].

Many studies on cardiac assist devices using skeletal muscle ventricle (SMV) require preconditioning for 6-9 weeks as a countermeasure to prevent skeletal muscle fatigue. Therefore this method does not seem to be indicated in cases of acute heart failure. However we performed experiments to develop Alternate-Drive Twin SMVs as a cardiac assist device without preconditioning. Adult mongrel dogs were used. In order to obtain adequate alternating SMV during pattern, fundamental experiments were performed. The function of SMVs prepared by rolled pedunculated sartial muscle was studied hydrodynamically in three groups; continuous driving for one hour in group a (n = 3): intermittent driving for 3 hours in group b (n = 15): intermittent driving for 12 hours in group c (n = 3). Group b was divided into three subgroups with interval for 10 minutes in subgroup I (n = 5), for 20 minutes in subgroup II (n = 5), for 30 minutes in subgroup III (n = 5). In group b and c, the recess interval between driving was set the same as the driving interval in each subgroup. All SMVs were stimulated by electrical bursts. In every experiment pump pressure, pump max dp/dt and pump stroke work index/10 kg body weight were measured for 3 hours. In subgroups I and II, pump function decreased gradually, however, the parameters did not show any change for up to 3 hours in subgroup III. We defined the reduction ratio as the difference of parameters before and after driving divided by the value at the start of driving.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1990

Increased accumulation of cytosine arabinoside in human leukemic cells and enhancement of its cell-killing activity by uridine.

The effects of uridine(UR) on the cell-killing activity of cytosine arabinoside(ara-C) against human leukemic cells, MOLT-4, and on ara-C accumulation in cells were studied. The 50% lethal dose(LD50) of ara-C as determined by clonogenic assay was decreased to 5.0 x 10(-8) mol from 9.0 x 10(-7) mol after 3 days exposure to 10(-3) mol of UR. The accumulation of 3H-ara-C at 24 and 48 h was significantly increased in culture medium containing 10(-8) mol of 3H-ara-C and 10(-3) mol of UR (5,129 +/- 123.5 vs 2,554 +/- 115.5 cpm/10(5) cells at 24 h, p less than 0.01, and 5,772 +/- 123.2 vs 1,372 +/- 51.8 cpm/10(5) cells at 48 h, p less than 0.01). It is noteworthy that cell-killing activity of ara-C against human leukemic cells was enhanced by the combination with a nucleoside(UR), but not with antileukemic agents.

Cell Survival↗
PubMed1990

[Hemolysis and red cell deformability during cardiopulmonary bypass--the effect of prostaglandin E1 for prevention of hemolysis].

Prevention of hemolysis which is related to renal failure during cardiopulmonary bypass (CPB) is very important. We discussed the relationship between hemolysis and red cell deformability during CPB, and moreover the effect of PGE1 to reduce hemolysis. PGE1 was given during CPB (10 approximately 20 ng/kg/min). Red cell deformability was measured using 20% Ht red cell suspension and Nucleopore Microfilter (pore size: 5 mu). Red cell filtration rate (RFR: microliter/sec) was calculated as a value of red cell deformability. Red cell deformability (RFR: microliter/sec) was reduced during CPB in almost all patients. Secondly, plasma Hb (mg/dl) was measured in the controls (n = 8) and PGE1 group (n = 12). The mean pre-bypass level were 20.6 in the control group and 23.8 in the PGE1 group. The mean values of plasma Hb at 30, 60, 90 and 120 min of CPB were 37.8, 52.4, 52.3 and 61.2 in the control group and 24.1, 25.0, 26.3 and 29.0 in the PGE1 group. Our study showed conclusively that CPB has a detrimental effect on red cell deformability and that this effect is accentuated by prolongation of CPB time. PGE1 lessened the decrease in red cell deformability during CPB and was shown to be very effective for prevention of hemolysis.

Alprostadil↗
PubMed1990

[Comparison of early clinical results of contact laser thermal angioplasty with a metal hot tip with balloon angioplasty].

Contact laser thermal angioplasty with a metal hot tip heated by an Argon laser system (Trimedyne Inc.) was performed on 34 peripheral arterial occlusive or stenotic regions (7 iliac, 20 femoral and 7 popliteal arteries) in 22 patients with ASO. The early clinical results of laser angioplasty were investigated by comparing those of 15 patients treated by percutaneous transluminal balloon angioplasty (PTA). There was no perforation of the arterial wall caused by thermal ablation with the hot tip heated by repeated pulses under power conditions of 10 watts of laser energy for 5 seconds. Detachment of the hot tip caused by frequent healing without a sufficient period of tip cooling was observed in 2 cases. Acute thrombosis was observed in 1 patient during reconstruction of the proximal artery. The initial success rate of laser angioplasty and PTA was 91.2% and 86.7%, respectively. Re-stenosis or occlusion was observed in 7 of 31 regions 6 months after laser angioplasty. Satisfactory results were not obtained in the femoral artery. The overall patency rate of laser angioplasty and PTA was 77.4% and 69.2%, respectively. The initial success rate of laser angioplasty in totally obstructed arterial regions was higher than that of PTA.

Aged↗
PubMed1989

Involvement of protein kinase in the regulation of beta-adrenergic receptors by antidepressants.

The role of serotonin (5-HT) and protein kinases in the regulation of the beta-receptor induced by typical and atypical antidepressants was investigated. Treatment with either mianserin or maprotiline for seven days produced a significant decrease in the beta-receptor density measured 6h after the last dose. The reduction in beta-receptors disappeared within 24h. However, combined treatment of mianserin or maprotiline with either fluoxetine or 5-hydroxytryptophan significantly decreased beta-receptors even 24h after the last dose. Following treatment with p-chlorophenylalanine the reduction in beta-receptors induced by desipramine was reversible within 24h. These results demonstrate that an increase in the synaptic 5-HT availability may contribute to the prolongation of the beta-receptor down-regulation by antidepressants. The intraventricular infusion of 12-0-tetradecanoyl-phorbol-13-acetate (TPA), a potent protein kinase C (PK-C) activator for seven days caused a significant decrease in beta-receptors, while forskolin or dibutyryl cyclic adenosine monophosphate had no influence on the receptor. The TPA-induced and desipramine-induced decreases in beta-receptors were not additive, suggesting that a similar mechanism is involved. The infusion of the PK-C inhibitor 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7) caused an inhibition of the desipramine-induced decrease in beta-receptors. It is suggested that the beta-receptor down-regulation by antidepressants might be also regulated by PK-C through 5-HT-Ca2+-inositol-phospholipid systems.

5,7-Dihydroxytryptamine↗
PubMed1989

[Treatment of acute lymphocytic leukemia in adult].

Since April, 1978 to October, 1988, 66 acute lymphocytic leukemia (ALL) patients aged 15 to 79 (21 L1, 43 L2, 2 L3/6 Ph1+) were treated with 3 different therapeutic protocols. The drugs used for induction were VCR (VDS) + Pred, followed by DNR + VCR (VDS) + 6MP + Pred and VCR (VDS) + L-asp + Pred in protocol I, Ad + VCR + Pred in protocol II and DNR + VCR + Pred in protocol III. Complete remission (CR) was attained in 72.7% of 66 patients. The CR rate of each group as followings; 71.4% in protocol I and 75.0% in protocol II and III, respectively. The median duration of remission was 10.2 months + and the probability of being in continuous CR at 3 years was 21.9%. For the 48 patients in remission the median survival was 17.8 months and the probability of being alive at 3 years was 24.3%. The intensified induction and consolidation therapy is expected in the cure oriented treatment of adult ALL.

Adolescent↗