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Biomedical subjects

A Ishihara

Publications and source records attributed to A Ishihara.

At least 163 records · Page 9Linked to original sources
PubMed1991

The relationship of voluntary running to fibre type composition, fibre area and capillary supply in rat soleus and plantaris muscles.

Twenty 4-week-old Wistar rats exercised voluntarily in running wheels each day for 45 days. Fibre type composition, fibre cross-sectional area and the number of capillaries around a fibre of the slow-twitch soleus and fast-twitch plantaris muscles were examined and compared with animals which had no access to running wheels. The exercise group had a higher percentage of fast-twitch oxidative glycolytic (FOG) fibres and a lower percentage of fast-twitch glycolytic (FG) fibres in the deep portion of the plantaris muscle. The area of FOG fibres in the surface portion of the plantaris muscle was also greater in the exercise group. In the exercised animals, there was a positive relationship between the running distance and the area of FOG fibres in both the deep and surface portions of the plantaris muscle. In addition, the running distance correlated positively with the percentage of FOG fibres and negatively with that of FG fibres in the deep portion of the plantaris muscle. There were no relationships between the running distance and fibre type composition, or fibre area and capillary supply in the soleus muscle. These results suggested that the increase in the percentage and area of FOG fibres in the fast-twitch muscle was closely related to voluntary running.

Animals↗
PubMed1991

Effects of body suspension on soleus muscle fibres and spinal motoneurones in the rat.

1. After 14 days of body suspension, fibre type composition and fibre cross-sectional area in the soleus muscle of 17-week-old male Sprague-Dawley rats were investigated. Oxidative enzyme activity of soleus motoneurones in the spinal cord was also examined. 2. After suspension, soleus muscle weight decreased by 44.2%, the cross-sectional area of SO and FOG fibres decreased by 60.4% and 58.6%, respectively. 3. The percentage of fibre types was not changed by suspension. However, ATPase activity after alkaline preincubation was markedly inhibited in FOG fibres. 4. Oxidative enzyme activity of soleus motoneurones was not changed by suspension. 5. This study demonstrates that using mature animals body suspension induces atrophy of fast- and slow-twitch fibres accompanied with the selective inhibition in ATPase activity of fast-twitch fibres, and without changes in histochemical profiles of the corresponding motoneurones.

Animals↗
PubMed1991

Lateral diffusion and retrograde movements of individual cell surface components on single motile cells observed with Nanovid microscopy.

A recently introduced extension of video-enhanced light microscopy, called Nanovid microscopy, documents the dynamic reorganization of individual cell surface components on living cells. 40-microns colloidal gold probes coupled to different types of poly-L-lysine label negative cell surface components of PTK2 cells. Evidence is provided that they bind to negative sialic acid residues of glycoproteins, probably through nonspecific electrostatic interactions. The gold probes, coupled to short poly-L-lysine molecules (4 kD) displayed Brownian motion, with a diffusion coefficient in the range 0.1-0.2 micron2/s. A diffusion coefficient in the 0.1 micron2/s range was also observed with 40-nm gold probes coupled to an antibody against the lipid-linked Thy-1 antigen on 3T3 fibroblasts. Diffusion of these probes is largely confined to apparent microdomains of 1-2 microns in size. On the other hand, the gold probes, coupled to long poly-L-lysine molecules (240 kD) molecules and bound to the leading lamella, were driven rearward, toward the boundary between lamelloplasm and perinuclear cytoplasm at a velocity of 0.5-1 micron/min by a directed ATP-dependent mechanism. This uniform motion was inhibited by cytochalasin, suggesting actin microfilament involvement. A similar behavior on MO cells was observed when the antibody-labeled gold served as a marker for the PGP-1 (GP-80) antigen. These results show that Nanovid microscopy, offering the possibility to observe the motion of individual specific cell surface components, provides a new and powerful tool to study the dynamic reorganization of the cell membrane during locomotion and in other biological contexts as well.

Adenosine Triphosphate↗
PubMed1991

Basal forebrain lesioned mice exhibit deterioration in memory acquisition process in step through passive avoidance test.

Effects of the basal forebrain (BF) lesion on memory and learning performances were investigated in mice. Eight-week-old male mice received bilateral BF lesion by delivering a radiofrequency current. From fifteen days after the surgery, the step through type passive avoidance task was performed daily for 10 days. Lesioned animals showed severe impairment in the acquisition process of this task, but not in the retention process. Ambulatory activity of the BF-lesioned mice did not differ from those of the control group, suggesting the observed learning impairment was not due to the alteration of motor activity. These results indicate that a memory impaired model mice can be successfully made by the radiofrequency lesion of bilateral BF neurons.

Animals↗
PubMed1991

Histochemical differentiation of fibers in the rat slow and fast twitch muscles.

Wistar male rats were sacrificed at 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, and 21 days, and at 5 and 10 weeks of age. The histochemical differentiation of slow twitch soleus and fast twitch plantaris muscle fibers was examined from the enzyme activities of adenosine triphosphatase (slow- or fast-contracting), succinate dehydrogenase (high- or low-oxidative), and alpha-glycerophosphate dehydrogenase (high- or low-glycolytic). The soleus muscle fibers differentiated into slow-contracting (S) and fast-contracting (F) fibers at 7 days of age. In the plantaris muscle, differentiation into S and F fibers in the deep portion occurred earlier (9 days) than in the superficial portion (11 days). Thereafter, fiber type shifts between S and F were observed in both muscles. Differentiation into fast-contracting oxidative glycolytic (FOG), fast-contracting glycolytic (FG), and slow-contracting oxidative (SO) fibers occurred in both muscles at 15 and 17 days of age. After subdivision into the three fiber types, a type shift from FOG to FG was observed in both the deep and superficial portions of the plantaris muscle.

Adenosine Triphosphatases↗
PubMed1991

[Study of patency of minor duodenal papilla--comparison between pigment method combined with pH sensor and pancreatographic method].

We investigated the patency of minor duodenal papilla in 25 cases that had presented normal pancreatogram by using the endoscopic retrograde pancreatographic (ERP) method and a pH sensor-combined indigo carmine pigment method. The pigment method allowed us to classify the function of minor papilla into three types according to pancreatic juice excretion pre- and post-secretin administration (Type I), excretion after secretin administration (Type II), and no excretion even after secretin administration (Type III). Twelve cases belonged to Type I, 4 cases to Type II and 9 cases to Type III. By ERP method, terminal shapes of the Santorini's duct were classified as stick type, cystic type and branch type. 19 cases were considered stick type, 2 cases cystic type and 4 cases branch type. Eighteen cases were identified as patent minor papilla under ERP method. There were two cases alleged to be patent under the ERP but without pancreatic juice excretion. Therefore, the necessity of pigment method was confirmed for investigation of the function of minor papilla.

Adult↗
PubMed1991

[Chronic hemorrhagic empyema developed in thirty three years after the right pneumonectomy--a case report].

A 55-year-old man was admitted because of exertional dyspnea. He had the right pneumonectomy thirty three years ago. Chest X-ray showed the mediastinal shift to the left. And chest CT scan showed right intrathoracic mass. The bloody pleural effusion was aspirated (Hb 9.4 g/dl) and its examination revealed Staphylococcus epidermidis. We resected the empyema cavity. During the operation, massive bleeding was experienced (total 23200 ml). Pathologically, micro blood vessels were marked in the organized hematomas and the pleura. Chronic hemorrhagic empyema is a specific type of chronic empyemas and it is dangerous to remove of the hematomas because of massive bleeding.

Chronic Disease↗
PubMed1991

[Pleuropneumonectomy with combined resection of diaphragma, superior vena cava, and pericardium, for invasive thymoma with pleural dissemination].

A 63-year-old female was admitted to our hospital with chief complaint of exertional dyspnea. Right massive pleural effusion was found. After chest drainage was performed, chest CT scan and MRI showed several masses in the anterior mediastinum and on the diaphragma. Mesothelioma was suspected for needle biopsy. Pleuropneumonectomy with combined resection of diaphragma, superior vena cava and pericardium was performed. Histologically, the Tumor was mixed thymoma. She is well and alive for three years after operation. Pleuropneumonectomy may be a choice of effective treatments for invasive thymoma with pleural dissemination.

Diaphragm↗
PubMed1991

[Legionnaires' disease with mediastinal lymph nodes swelling, diagnosed by open lung biopsy--a case report].

Legionnaires' disease in a 37-year-old male who had had silicosis was reported. He was admitted because of dyspnea. The chest X-ray film and CT scan showed infiltrative shadow and swelling of mediastinal lymph nodes. Open lung biopsy was done and Legionella pneumohila was detected. REP and EM were started and infiltrative shadow of X-ray was disappeared. Pleuro-pneumonectomy and thoracoplasty were performed because of hemoptysis and postoperative empyema. The patient is now well.

Adult↗
PubMed1991

[A case of pneumothorax which was operated with the axillary longitudinal small incision].

A pneumothorax usually occurs in young men. From the cosmetic point of view, the size of the skin incision should be considered to be minimal if surgery is applied for young pneumothorax patients. We reported a case of pneumothorax which was operated with a small longitudinal axillary skin incision, the size of which was 3.5 cm long. The patient was a 18-year-old high school student. He was admitted to our hospital with the diagnosis of spontaneous pneumothorax. His chest X-ray showed a moderate collapse of his left lung and bullae in his left apex. Tube drainage was performed and the collapsed lung re-expanded completely. Chest CT scan demonstrated that he had bullae in the apex of his left lung. No other lesions were found in the other part of both lungs. Surgery was indicated socially. Bullectomy was successfully performed with a small (3.5 cm) longitudinal axillary skin incision. We recommend this skin incision for young patients with pneumothorax if the chest CT scan confirms that the bullae or blebs are localized to the apex of superior segment of the lower lobe.

Adolescent↗
PubMed1990

Effects of hypobaric hypoxia on the oxidative capacity of the extensor digitorum longus motor units in the rat.

The fiber number, fiber type distribution, and succinate dehydrogenase activity were investigated from the fast-twitch extensor digitorum longus muscle of male rats exposed to 7 weeks of hypobaric hypoxia. The oxidative metabolic capacity of the motoneurons in the extensor digitorum longus neuron pool was also determined from quantitative histochemical analyses. The fiber number and oxidative enzyme activity of the muscle were not changed by hypoxia. An increase in the percentage of fast-twitch oxidative (FO) fibers and a concomitant decrease in the percentage of fast-twitch (F) fibers were observed in the hypoxic muscle. On the other hand, the oxidative capacity of small- to medium-sized alpha motoneurons (24-45 microns average soma diameter) was increased. The increase in the oxidative capacity of small- to medium-sized motoneurons and the type shift of muscle fibers from F (low-oxidative) to FO (high-oxidative) indicate that hypoxia enhances the oxidative capacity of particular motor units in the neuron pool.

Animals↗
PubMed1990

Oxidative metabolism of the rat soleus neuron pool following hypobaric hypoxia.

After 7 weeks of hypoxic acclimation, oxidative enzyme (succinate dehydrogenase) activity of motoneurons in the rat soleus neuron pool was examined. Although the total oxidative metabolism of the neuron pool was not changed, the oxidative enzyme activity of small to medium sized (25-45 microns average soma diameter) alpha motoneurons was increased. These results indicate that hypoxia preferentially enhances the oxidative capacity of specific motoneurons in the neuron pool.

Animals↗
PubMed1990

Comparative behavior of membrane protein-antibody complexes on motile fibroblasts: implications for a mechanism of capping.

A characteristic feature of fibroblast locomotory activity is the rearward transport across the leading lamella of various materials used to mark the cell surface. The two processes most frequently invoked as explanations for this transport phenomenon, called capping, are (a) retrograde membrane flow arising from directed membrane insertion and (b) rearward cortical cytoskeletal flow arising from cytoskeletal assembly and contraction. The retrograde lipid flow hypothesis, the most current form of the membrane flow scheme, makes explicit predictions about the movement of membrane proteins subjected to the postulated rearward lipid flow. Several of these predictions were tested by comparing the behavior of four membrane proteins, Pgp-1, Thy-1, H-2, and influenza HA0, identified by fluorescent antibodies. With the exception of Pgp-1, these proteins were uniformly distributed under nonaggregated conditions but were capped when aggregated into patches. In contrast, Pgp-1 was capped in similar time frames in both nonaggregated and aggregated states where the lateral diffusion coefficients were very different. Furthermore, the capping behavior of two tagged membrane proteins was markedly different yet both had similar diffusion coefficients. The results from these tests disprove the bulk membrane flow hypothesis and are at odds with explicit predictions of the retrograde lipid flow hypothesis for the mechanism of capping. This work, therefore, supports the alternative cytoskeletal-based mechanism for driving capping. Requirements for coupling cytoskeletal movement to membrane components are discussed.

Actins↗
PubMed1990

A case of a salivary calculus containing a limb of a shrimp--the structural analysis.

This study describes a case of a salivary calculus which contained the limb of a shrimp. Pathological findings seemed to show a stratiform structure of calculus around the foreign body at the center. However, when the cut surface of the salivary calculus was examined by a scanning electron microscope, it was suspected that the origin of the calculus was in another area next to the foreign body. As a result, it became clear that the foreign body was not the core, but that the core of the salivary calculus was somewhere else, and that the earlier foreign body theory needed to be reconsidered. As to the foreign body, the patient remembered eating a shrimp, which was probably the foreign body in question. The findings obtained from the analysis of other shrimp limb specimens were structurally similar. Therefore the suspicion that the foreign body was indeed the limb of a shrimp was increased.

Adult↗