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Biomedical subjects

A Ishihara

Publications and source records attributed to A Ishihara.

At least 199 records · Page 11Linked to original sources
PubMed1989

[Cardiac rupture secondary to left ventricular venting].

The cases of two patients with cardiac rupture secondary to left ventricular venting are reported. In the first patient, who had an aortocoronary bypass grafting, rupture was found in the posterolateral wall of the left ventricle just before closing the chest. It was successfully managed by placing sutures. The cause of rupture was thought to be the advancing venting cannula tip introduced into the left ventricle from the superior right pulmonary vein. In the second patient, who had MVR, AVR, and VSD and ASD closure, rupture occurred in the posterior wall of the left atrium on the 4th postoperative day. The patient died instantly because of profound hemorrhagic shock. Rupture of the left atrium was thought to have occurred secondary to distension of the left atrial wall incurred by lifting the unusually large heart for inserting and removing the venting cannula. These experiences made us decide to abandon routine left ventricular venting.

Assisted Circulation↗
PubMed1989

[Is left ventricular venting necessary in open heart surgery?].

In this study we intended to clarify the benefits of left ventricular venting by comparing the surgical results and clinical courses of 19 adult patients who underwent open heart procedures with venting and those of 44 adult patients who had open heart procedures without venting. All of the patients of both groups underwent operations for acquired heart diseases. The hospital mortality was 10.5% in the vent group and 2.3% in the no-vent group (NS). None of the deaths occurred due to the postoperative low output syndrome in either group. The incidence of spontaneous defibrillation was not different in the two groups, and no patients required postoperative IABP support in either group. The number of patients who needed catecholamine infusion for longer than 24 hours postoperatively were not statistically different in the two groups, and incidence of ventricular arrhythmias was not different in the two groups. The cardiac index determined 6 hours postoperatively was significantly higher in the no-vent group. The left atrial pressure in the no-vent group did not exceed 10 mmHg during cardiopulmonary bypass, if the central venous pressure was maintained below 7 mmHg. It was suggested that distension of the left ventricle and myocardial injuries do not occur during cardiopulmonary bypass without left ventricular venting, provided the central venous pressure is maintained below 6 or 7 mmHg.

Adult↗
PubMed1989

[Combined resection of the aortic wall using extracorporeal circulation in lung cancer patients].

Two cases of lung cancer performed combined resection of the aortic wall using extracorporeal circulation were discussed in this paper. One was 59-year old male and another was 63-year old male. Both had squamous cell carcinoma of the left upper lobe. CAT scan suggested the tumor invaded into the aortic wall, main pulmonary artery and left atrium in either patients. For the first case, separated perfusion to the upper half and lower half of his body, and for the second case, perfusion only to the lower half of the body were employed to resect and repair the aortic wall, using Dacron patch. For the first case, the left main pulmonary artery and the left atrial wall were resected in advance under the regular extracorporeal circulation. The first case died of the recurrence of the tumor 1 year and 7 months post-operatively, resulting the hemorrhage into the thoracic cavity. The second case died of empyema resulting massive hemorrhage from the anastomotic site of the patch 3 months post operatively. We think some managements such as the coverage of the synthetic graft with the omentum would be needed.

Aorta↗
PubMed1988

Effects of age on the number and histochemical properties of muscle fibers and motoneurons in the rat extensor digitorum longus muscle.

The number and histochemical properties of muscle fibers and motoneurons were studied in the extensor digitorum longus muscle in female albino rats at the ages of 10, 60 and 120 weeks. The number of fast twitch glycolytic (FG) fibers was decreased at 60 weeks, while that of fast twitch oxidative glycolytic (FOG) fibers was decreased at 120 weeks. The number and oxidative enzyme activity of motoneurons were decreased later at 120 weeks. Thus, it is suggested that the decrease in FG fibers at 60 weeks was due to selective muscle fiber atrophy or to degeneration of neuromuscular junctions, while on the other hand, the decrease in FOG fibers at 120 weeks was due mainly to both a decrease in motoneurons and a type shift of fibers from FOG to FG.

Aging↗
PubMed1988

Soma size and oxidative enzyme activity of motoneurones supplying the fast twitch and slow twitch muscles in the rat.

The relationship between soma size and oxidative enzyme activity of motoneurones supplying the fast twitch muscle and the slow twitch muscle was examined. Horseradish peroxidase was injected into the extensor digitorum longus (fast twitch) muscle and the soleus (slow twitch) muscle to retrogradely label corresponding motoneurones of the rat spinal cord. There was a negative relation between soma size and oxidative enzyme activity of motoneurones in a particular neurone pool. The alpha motoneurones supplying the slow twitch muscle had higher oxidative enzyme activities than identical size motoneurones supplying the fast twitch muscle. The present results suggest that there is a difference between oxidative capacities of fast twitch and slow twitch neurone pools.

Animals↗
PubMed1988

Analysis of lateral redistribution of a plasma membrane glycoprotein-monoclonal antibody complex [corrected].

The lateral redistribution of a major murine glycoprotein, GP80, was studied on locomoting fibroblasts, using rhodamine-conjugated mAbs and ultralow light level digitized fluorescence microscopy. Confirming an earlier study (Jacobson, K., D. O'Dell, B. Holifield, T.L. Murphy, and J. T. August. 1984. J. Cell Biol. 99:1613-1623), the distribution of GP80 was coupled with cell locomotion; motile cells exhibited a gradated distribution of the GP80-mAb complex over the cell surface, increasing from the front to the rear, whereas stationary cells exhibited a nearly uniform GP80 distribution. By monitoring locomoting single cells, we found the gradated fluorescence distribution to be maintained as an approximate steady state. Newly extended leading edges were almost devoid of the fluorescence labeling. This was strikingly demonstrated in prechilled cells in which the extension of fluorescence-free leading edges caused a pronounced boundary between fluorescent and nonfluorescent zones. Subsequently this boundary eroded gradually in a manner consistent with diffusional relaxation. Evidence indicated that the GP80 redistribution was primarily caused by the lateral motion of GP80 in the plasma membrane and not via intracellular membrane traffic. Two cell locomotion models which, in principle, could account for the GP80 redistribution were tested: the retrograde lipid flow (RLF) model (Bretscher, M. S., 1984. Science (Wash. DC). 224:681-686) and an alternative hypothesis, the retraction-induced spreading (RIS) model. The predictions of these models were stimulated by computer and compared with experiment to assess which model was more appropriate. Whereas both models predicted steady-state gradients similar to the experimental result, only the RIS model predicted the lack of retrograde movement of the fluorescent boundary.

Animals↗
PubMed1988

Fibronectin receptor exhibits high lateral mobility in embryonic locomoting cells but is immobile in focal contacts and fibrillar streaks in stationary cells.

The dynamic process of embryonic cell motility was investigated by analyzing the lateral mobility of the fibronectin receptor in various locomotory or stationary avian embryonic cells, using the technique of fluorescence recovery after photobleaching. The lateral mobility of fibronectin receptors, labeled by a monoclonal antibody, was defined by the diffusion coefficient and mobile fraction of these receptors. Even though the lateral diffusion coefficient did not vary appreciably (2 X 10(-10) cm2/S less than or equal to D less than or equal to 4 X 10(-10) cm2/S) with the locomotory state and the cell type, the mobile fraction was highly dependent on the degree of cell motility. In locomoting cells, the population of fibronectin receptors, which was uniformly distributed on the cell surface, displayed a high mobile fraction of 66 +/- 19% at 25 degrees C (82 +/- 14% at 37 degrees C). In contrast, in nonmotile cells, the population of receptors was concentrated in focal contacts and fibrillar streaks associated with microfilament bundles and, in these sites, the mobile fraction was small (16 +/- 8%). When cells were in a stage intermediate between highly motile and stationary, the population of fibronectin receptors was distributed both in focal contacts with a small mobile fraction and in a diffuse pattern with a reduced mobile fraction (33 +/- 9%) relative to the diffuse population in highly locomotory cells. The mobile fraction of the fibronectin receptor was found to be temperature dependent in locomoting but not in stationary cells. The mobile fraction could be modulated by affecting the interaction between the receptor and the substratum. The strength of this interaction could be increased by growing cells on a substratum coated with polyclonal antibodies to the receptor. This caused the mobile fraction to decrease. The interaction could be decreased by using a probe, monoclonal antibodies to the receptor known to perturb the adhesion of certain cell types which caused the mobile fraction to increase. From these results, we conclude that in locomoting embryonic cells, most fibronectin receptors can readily diffuse in the plane of the membrane. This degree of lateral mobility may be correlated to the labile adhesions to the substratum presumably required for high motility. In contrast, fibronectin receptors in stationary cells are immobilized in focal contacts and fibrillar streaks which are in close association with both extracellular and cytoskeletal structures; these stable complexes appear to provide firm anchorage to the substratum.

Animals↗
PubMed1988

Emesis induced by cancer chemotherapeutic agents in the Suncus murinus: a new experimental model.

Acute emetic responses to seven cancer chemotherapeutic agents (adriamycin, bleomycin, cisplatin, cyclophosphamide, 5-fluorouracil, methotrexate, mitomycin C) were studied in the Suncus murinus. Intravenous injection of the drugs caused vomiting with various latency. Cisplatin-induced emesis was prevented by the pretreatment with metoclopramide or chlorpromazine but not with domperidone. These results indicate that the Suncus murinus is a useful animal for testing emetic activities of cancer chemotherapeutics and antiemetic activities of prophylactic drugs.

Animals↗
PubMed1988

Histochemical properties of intrafusal fibers in the soleus muscle of the aged rat.

ATPase reaction profiles of intrafusal fibers in the muscle spindle of the soleus muscle of 135-week-old rats were examined. Nuclear bag1 fibers contained an acid- and alkaline-labile form of the enzyme or an acid-labile and alkaline-stabile form, nuclear bag2 fibers contained an acid- and alkaline-stabile form, and nuclear chain fibers contained an acid-labile and alkaline-stabile form. These results indicate that the enzyme histochemical heterogeneity of intrafusal fibers is well-preserved during ageing.

Adenosine Triphosphatases↗
PubMed1988

High-molecular-weight neutral proteinase of rat ascites hepatoma cells and their collagenolytic activity.

A high-molecular-weight proteinase in rat ascites hepatoma AH109A cells was purified to apparent homogeneity by conventional chromatographic techniques. The purified proteinase degraded over the broad pH range, 7.0-9.0, not only denatured hemoglobin but also type I and IV collagen in the absence of calcium. Its activity was maximum at pH 8.0, heat-labile and affected by thiol reagents. Serine proteinase inhibitors such as diisopropyl fluorophosphate, soybean trypsin inhibitor, leupeptin, and antipain also partially inhibited its activity. The enzyme was found mainly in the cytosol fraction, and had a molecular weight of 450 kilodaltons (Kd) as determined by gel filtration chromatography and showed a single band on polyacrylamide gel electrophoresis under nondenaturing condition, although it was dissociated into lower-molecular-weight subunits, 25.5-32 Kd in the presence of sodium dodecyl sulfate and 2-mercaptoethanol. These properties suggested that it was a kind of a cytosolic high-molecular-weight proteinase. The collagenolytic activity of this proteinase may play an important role in cancer cell invasion and metastasis.

Animals↗
PubMed1988

Human trabecular meshwork organ culture.

Human trabecular meshwork obtained from postmortem eyes was maintained in organ culture condition up to 12 weeks. The explants were dissected into specimens of three different sizes. Types 1 and 2 specimens were larger than 4 mm square and 1 mm thick, and type 3 specimens were about 1 mm3. Each specimen was placed in a depression made in the center of an agar block and the block was placed in a plastic culture dish. The space between the agar block and the culture dish was filled with liquid medium consisting of MEM Eagle supplemented with 10% fetal bovine serum, 10% chick embryo extract and 200 U/ml penicillin G. Afterwards, the explant was incubated in 5% CO2 with 100% humidity. Types 1 and 2 specimens maintained a normal appearance on electron microscopy during the entire 12 weeks of culture, while type 3 specimens showed marked cellular activation and cell loss soon after explantation. Morphometric studies regarding cell number in sections for light microscopy obtained from types 1 and 2 specimens revealed good preservation of trabecular cells during the 12 weeks of culture. Our culture system may be useful in investigating the direct effects produced on human trabecular meshwork by photocoagulation and various agents, for example anti-glaucoma drugs, steroids and viscoelastic materials.

Cadaver↗
PubMed1988

[Effects of hypobaric-hypoxia on the total number and histochemical properties of the soleus muscle fibers and motoneurons in the rat].

After 7 weeks of hypobaric-hypoxia adaptation, horseradish peroxidase was injected into the soleus muscle to label motoneurons of the spinal cord in rats. Fiber type distribution in the soleus muscle and oxidative enzyme activity of motoneurons innervating the soleus muscle were examined. Fiber type was converted from slow-twitch-oxidative (SO) to fast-twitch-oxidative-glycolytic (FOG). Oxidative enzyme activity of motoneurons (25-45 micron soma diameter) was increased. However, oxidative capacity of larger motoneurons (greater than or equal to 45 micron soma diameter) was not changed. These data suggest that the lack of increase in oxidative capacity of larger motoneurons (innervating SO units) by hypoxia secondarily causes fiber type shift from SO to FOG.

Animals↗
PubMed1987

Effects of ageing on the total number of muscle fibers and motoneurons of the tibialis anterior and soleus muscles in the rat.

The age-related changes in the total number of muscle fibers and motoneurons of the tibialis anterior and soleus muscles were studied using 10-, 65-, and 135-week-old rats. The number of fast twitch muscle fibers was decreased at age 65 weeks, while the numbers of slow twitch fibers and of alpha motoneurons were decreased only later, at age 135 weeks. Therefore, the degenerative process of muscle fibers differs with the fiber type.

Aging↗
PubMed1987

The Thy-1 antigen exhibits rapid lateral diffusion in the plasma membrane of rodent lymphoid cells and fibroblasts.

Thy-1 is a plasma membrane protein, but its primary structure lacks the typical membrane-spanning sequence. Recent studies revealed that a glycophospholipid is covalently bound to the carboxyl terminus, suggesting that the protein is integrated into the plasma membrane by this lipid moiety. Lateral diffusion of Thy-1 was measured in mouse thymocytes, lymphoma cells, and fibroblasts by the fluorescence recovery after photobleaching technique. Thy-1 was labeled with rhodamine-conjugated anti-Thy-1 monoclonal antibodies. Diffusion coefficients of 2-4 X 10(-9) cm2/sec were obtained for the antigen-antibody complex in all the cell types. About 50% of the Thy-1 was mobile. The diffusion coefficient for the mobile fraction of Thy-1 is considerably larger than the diffusion coefficients of many other plasma membrane proteins. Rather, the diffusion coefficient of Thy-1 is similar to those of lipid analogs embedded in the same membrane, providing strong support for the suggested lipid anchoring of this antigen.

Animals↗
PubMed1987

Signet ring cell carcinoma in a polyp of the colon. A case report of a six-year-old boy.

Undifferentiated adenocarcinoma of the colon occurring in a 6-year-old boy was presented. The tumor characterized by the signet ring cell appearance developed in a polyp of the descending colon. The signet ring cell carcinoma is in general a rare morphologic form of colonic carcinoma. According to our review of the literature there have been described 16 patients under 10 years of age with colonic or rectal carcinoma, disclosing 2 cases of undifferentiated or signet ring cell carcinoma including the present case. In children, mucin producing adenocarcinoma is the most predominant type of colonic carcinoma, and 48% of the colonic carcinomas are of signet ring cell carcinoma in children under 17 years of age.

Adenocarcinoma, Mucinous↗