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Biomedical subjects

Y Ohira

Publications and source records attributed to Y Ohira.

At least 91 records · Page 5Linked to original sources
PubMed1994

Responses of contractile properties in rat soleus to high-energy phosphates and/or unloading.

Responses of contractile properties of soleus to unloading and/or changes in high-energy phosphate contents were studied in rats. Reduction of high-energy phosphates, especially phosphocreatine, in ankle extensors was induced by feeding beta-guanidinopropionic acid (beta-GPA). The major finding in the study was that the fatigability and speed-related contractile properties responded to unloading and creatine supplementation in a similar manner. The high-energy phosphate contents tended to be elevated after 10-d supplementation of creatine and hindlimb suspension. The shift toward slow-type, mainly due to an increased one-half relaxation time, was seen in rats fed beta-GPA. Such a shift was reversed by feeding creatine or by hindlimb suspension; however, the suspension-induced shift of contractile properties toward fast-type was not prevented completely by beta-GPA feeding. Although the muscle fatigue resistance did not change by beta-GPA feeding alone, the decrease in fatigue resistance following suspension and creatine supply was less in the beta-GPA group. It is suggested that the levels of high-energy phosphates and tension production play important roles in the regulation of contractile properties of the soleus muscle.

Animals↗
PubMed1994

Non-insulin and non-exercise related increase of glucose utilization in rats and mice.

The effects of high-energy phosphate contents in muscles on glucose tolerance and glucose uptake into tissues were studied in rats and mice. Enhanced glucose tolerance associated with depleted high-energy phosphates and elevated glycogen content in muscles and liver was observed in animals fed creatine analogue beta-guanidinopropionic acid (beta-GPA). Distribution of infused 2-[1-14C]deoxy-D-glucose in tissues especially in the soleus muscle, kidney, and brain was greater in mice fed beta-GPA than controls. The glucose uptake was decreased when the contents of ATP and glycogen were normalized following creatine supplementation. Plasma insulin in animals at rest was lower and its concentration after intraperitoneal glucose infusion tended to be less in animals fed beta-GPA than controls (p > 0.05), although the pattern of insulin response to glucose loading was similar to the control. The daily voluntary activity in beta-GPA fed mice was also less than controls. These results suggest that improved glucose tolerance is not related to elevated insulin concentration and/or decreased glycogen following exercise. Such improvement may be due to an increased mitochondrial energy metabolism caused by depletion of high-energy phosphates.

Animals↗
PubMed1994

[An approach to home therapy for cancer pain patients].

Recently, in consideration of cost performance and improvement in quality of life (QOL) of the patient, the significance of home care and outpatient treatment has also been recognized in Japan. A terminal cancer patient who had local recurrence in the pelvic region after surgery for rectum carcinoma, was treated for cancer pain by us with a continuous epidural infusion of morphine by means of a prolonged operating continuous infusion device. The treatment made home therapy possible and allowed the patient to return to normal social activities. Based on this case, the significance of and issues regarding home therapy are discussed in this study.

Costs and Cost Analysis↗
PubMed1993

[Effects of various histamine H2-receptor antagonists on gastrointestinal motility and gastric emptying].

Effects of various histamine H2-receptor antagonists (H2-RA) on gastrointestinal motility and gastric emptying were investigated. Ranitidine, nizatidine and cimetidine dose dependently induced contractions over the entire gastrointestinal tract, and the order of their effects was ranitidine > nizatidine > cimetidine. Roxatidine or famotidine had no effects on motility of the gastrointestinal tract. Ranitidine and nizatidine also induced contractions during the postprandial period and facilitated gastric emptying, while cimetidine, roxatidine or famotidine did not influence gastric emptying. Since acid reduction is thought to be the most important element of the treatment of peptic ulcer and reflux esophagitis, it was inferred that administration of a H2-RA selected with consideration of its property of facilitating gastrointestinal motility is effective in the treatment of patients with abnormal gastrointestinal motility.

Animals↗
PubMed1993

[A case of Sjögren's syndrome accompanied by lymphadenopathy and IgG4 hypergammaglobulinemia].

A 78-year-old male patient suffered from slight dryness of his mouth and eyes, which was followed by swelling of the parotid and submandibular glands on both sides. Subsequently, he developed generalized lymphadenopathy accompanied by hypergammaglobulinemia IgG 7740 mg/dl, main subclass: IgG4, 5800 mg/dl. Histopathological examination of lymph nodes from his left neck showed follicular proliferation of plasma cells containing cytoplasmic kappa and lambda chains of IgG4, without destruction of the lymph node structure. His serum showed very low levels of complement: 0 U/ml of CH 50, 14 mg/ml of C3 and less than 11 mg/ml of C4. During treatment with prednisolone at 30 mg/day, the swelling of the salivary glands and lymph nodes reduced the IgG and IgG4 decreased and the complement increased. Finally, all lymph nodes, IgG and complement abnormalities were normalized. Anticomplementariness of IgG4 was demonstrated in this patient.

Aged↗
PubMed1992

Rat soleus muscle fiber responses to 14 days of spaceflight and hindlimb suspension.

Morphological and enzymatic responses in fibers expressing fast, slow, or both types of myosin heavy chain (MHC) were studied in rats after 14 days of spaceflight (COSMOS 2044) or hindlimb suspension. Although the percentage of slow-twitch fibers was unchanged, a higher percentage of fibers that expressed both slow and fast MHC was observed in flight and suspended rats than in synchronous ground-based controls. The soleus was 25 and 34% smaller than control after 14 days of flight and suspension, with the reduction in fiber cross-sectional area (CSA) being greater in slow- than in fast-twitch fibers in both experimental groups. The activities of succinate dehydrogenase (SDH) and alpha-glycerophosphate dehydrogenase (GPD) were not significantly affected by flight or suspension. The total SDH activity (i.e., SDH activity x CSA) decreased significantly in the slow-twitch fibers of the flight and the fast-twitch fibers of the suspended rats, in large part due to fiber atrophy. A shift in MHC expression in 14 and 9% of the fibers in flight and suspended rats occurred without a change in myosin adenosinetriphosphatase activity. The SDH and GPD activities of the fibers that expressed both slow and fast MHC were slightly higher than the slow-twitch fibers and slightly lower than the fast-twitch fibers. These data indicate that events were initiated within 14 days of spaceflight or suspension that began to reconfigure the protein profiles of 9-14% of the slow-twitch fibers from typical slow-twitch toward those of fast-twitch fibers, while all fibers were dramatically losing total protein.(ABSTRACT TRUNCATED AT 250 WORDS)

Adenosine Triphosphatases↗
PubMed1992

Adaptation of fibers in fast-twitch muscles of rats to spaceflight and hindlimb suspension.

The adaptation of single fibers in medial gastrocnemius (MG), a fast-twitch extensor, and tibialis anterior (TA), a fast-twitch flexor, was studied after 14 days of spaceflight (COSMOS 2044) or hindlimb suspension. Cross-sectional area (CSA) and succinate dehydrogenase (SDH), alpha-glycerophosphate dehydrogenase (GPD), and myofibrillar adenosinetriphosphatase (ATPase) activities were determined in fibers identified in frozen serial cross sections. Fibers were categorized as light, dark, or intermediate on the basis of myosin ATPase staining and alkaline preincubation and immunohistochemically as reacting with slow, fast, or both slow and fast myosin heavy chain monoclonal antibodies. Because there was a close relationship between these two means of categorizing fibers, all fibers were categorized on the basis of the immunohistochemical reaction. The percentage of slow- and fast-twitch fibers of the MG and TA were unchanged in either group. Mean fiber size of all fibers, irrespective of type, was unaffected in either muscle after flight or suspension. The fibers that expressed both fast and slow myosin heavy chains were smaller than control in the MG of both experimental groups. Compared with control, the SDH and total SDH activities in the MG were significantly less in suspended rats, with the fast-twitch fibers showing the largest difference. The ATPase activity in the MG was higher in flight than in control or suspended rats. There were no significant effects of flight on fibers of the TA. In contrast, the TA in suspended rats had higher GPD activities than either control or flight rats.(ABSTRACT TRUNCATED AT 250 WORDS)

Adaptation, Physiological↗
PubMed1992

Muscle metabolism during exercise: anaerobic threshold does not exist.

Blood lactate level begins to increase at a certain work load or oxygen consumption which is called as anaerobic threshold (AT). However, numerous studies showed that anaerobic glycolysis is not the cause of the enhanced accumulation of blood lactate during exercise. Increased lactate production is seen even in fully aerobic muscles. Some studies suggest that elevation of lactate is due to a temporary imbalance between the rates of pyruvate formation by aerobic glycolysis and pyruvate utilization in the Krebs cycle. These results clearly suggest that AT does not exist.

Anaerobic Threshold↗
PubMed1991

Reduced growth of Ehrlich ascites tumor cells in creatine depleted mice fed beta-guanidinopropionic acid.

The effect of implantation of Ehrlich ascites tumor (EAT) cells on creatine distribution was investigated. It was also studied how depletion of creatine by feeding creatine-analogue beta-guanidinopropionic acid (beta-GPA) affects the growth of EAT cells in mice. Enhanced mobilization of creatine from host tissues to EAT cells against a greater concentration gradient was observed. The creatine (but not creatinine) level in blood plasma was lowered to 22% of the normal value by beta-GPA feeding alone and assimilation of 14C-creatine into EAT cells was inhibited. The growth of EAT cells was significantly reduced and the duration of survival of mice after implantation of EAT cells was extended when the creatine concentration was decreased. A decrease in daily food consumption and the degree of muscle atrophy after implantation of EAT cells was less in beta-GPA than control groups. In the creatine-depleted mice, the rate of increase in total EAT cell number and the volume of abdominal ascites were approximately half of the control values, and more dead EAT cells were observed. These results suggest that supplementation of beta-GPA inhibits creatine transfer to EAT cells and reduces the growth of cancer cells.

Administration, Oral↗
PubMed1991

Structure and mineral content in weight-bearing bones following hindlimb suspension in young rats.

Responses of structure and mineral content in weight-bearing bones to 1-week hindlimb suspension were studied in growing rats. The weight, volume, and length of femur, tibia, and fibula were less in suspended rats than cage controls, although there was no significant difference in the weight/volume ratio. The diameter of mid-shaft, the thickness of cortical bone, and the ratio of cortical bone thickness to femur diameter were significantly less in the suspended rats. The width of marrow space showed no differences, suggesting that the cortical bone was mainly affected. The sum of mineral content and the mineral content per diameter in the cross section of femurs were decreased following suspension, suggesting a change in the internal structure of cortical bone. Data also indicated that the reduction of femur diameter was caused by decreased thickness which is accompanied by the decreased mineral content of the cortical bone. It was suggested that there is a close relationship between the responses of bones and muscles to hindlimb suspension of young rats, although the degree of weight loss was greater in muscles than in bones.

Animals↗
PubMed1991

[A case of bilateral sudden hearing loss and vertigo caused by bilateral temporal bone metastasis from pancreatic carcinoma--comparison of clinical findings and temporal bone pathological findings].

We report temporal bone pathology in a 25-year-old man with bilateral temporal bone adenocarcinoma which was caused by metastasis from a primary lesion in the pancreas. The initial symptoms began with vertigo and headache and the patient noticed left hearing loss in the left ear on the following day. A few days later, he noticed hearing loss in the right ear, and bilateral hearing was totally lost within two weeks of the onset. In addition to severe bilateral sensorineural hearing loss, left IInd, bilateral Vth and VIIIth cranial nerve paralysis occurred. Brain CT showed multiple metastatic lesions in the brain. The patient's general condition rapidly deteriorated, and he died of acute pneumonia on the 42nd day after onset. At autopsy it was revealed adenocarcinoma of the tail and body of the pancreas and its metastasis to the brain and meninges. Pathological study of the temporal bone showed infiltration of carcinomatous cells along the VIIth and VIIIth nerves in the bilateral internal auditory canals.

Adenocarcinoma↗
PubMed1991

[Gallbladder function and CCK after gastrectomy].

Postgastrectomy cholelithiasis has become a problem and biliary tract dyskinesia has been cited as an etiologic factor. CCK is the most important gut hormone with respect to biliary tract function, so we conducted an experimental study of postgastrectomy gallbladder function and CCK levels which gave the following results: 1. Although postprandial gallbladder contraction for the most part occurred in response to endogenous CCK, another mechanism (the gastro-cholecystic reflex) seemed to be responsible for some of them. 2. The postgastrectomy decrease in postprandial gallbladder contraction appeared to be due to disappearance of this gastro-cholecystic reflex. 3. Gallbladder contraction occurred in association with postprandial CCK secretion following total gastrectomy and Roux-en-Y reconstruction, but the altered food passage route caused changes in the dynamics of CCK secretion, and this is believed to have had an influence on the gallbladder contractile response.

Animals↗
PubMed1989

Organ culture of frog muscle: maintenance of mass, enzyme levels, and contractile force.

This paper describes an organ culture system that maintains frog sartorius muscles in good condition for 5 days. In the absence of serum and insulin, muscles maintained at approximately 93% of resting length atrophied with significant decreases in dry weight, protein content, and contractile force, and in the levels of activity of citrate synthase, lactate dehydrogenase, and creatine kinase. Inclusion of 1.0 mU/ml of insulin in the culture medium prevented the decreases in muscle mass, twitch tension, and citrate synthase activity and minimized the decreases in lactate dehydrogenase, creatine kinase, and tetanic tension. Inclusion of 10% serum, in addition to 1 mU/ml insulin, in the medium did not have clear cut additional benefits. Stretching muscles to 110% of resting length (L0) resulted in marked deterioration with decreases in total protein, enzyme levels, and contractile force. Keeping muscles at approximately 93% L0 was as effective as maintenance at L0 in preventing atrophy and loss of contractile force and enzyme activities. This organ culture procedure, which maintains frog sartorius muscle in good condition without serum for at least 5 days, may provide a useful model for studying the regulatory mechanisms responsible for a variety of adaptations in muscle.

Animals↗
PubMed1989

Effects of denervation and deafferentation on mass and enzyme activity in rat skeletal muscles.

Effects of denervation and deafferentation on mass and enzyme activity of soleus and plantaris muscles were studied when the synergistic gastrocnemius was either intact or tenotomized in adult male Wistar rats. Denervation of the sciatic nerve at L4 and L5 induced a severe atrophy (approximately 50%) in both soleus and plantaris within 2 weeks. Deafferentation at L4 and L5 also caused a decrease in muscle weight for soleus and plantaris (approximately 11 and 24%, respectively). No compensatory response to the tenotomy was induced either for muscle weight or enzyme activity in both denervated and deafferentated muscles. It is suggested that the efferent information(s) through the nerve fibers has an important effect of the regulation of both muscle mass and enzyme activity. Its effect on the activities was greater in mitochondrial than cytoplasmic enzymes. The data also suggest that the afferent information(s) plays a significant role for the regulation of muscle mass, including an induction of compensatory hypertrophy, but not for enzyme activity.

3-Hydroxyacyl CoA Dehydrogenases↗