Microinjection of ouabain into crab single muscle fibers and the mechanism of ouabain potentiation

In order to clarify the mechanism of the potentiating effect of ouabain on contraction, a study was made of the effect of microinjection of 1.5 μL of ouabain on contractile responses and 22Na efflux, using single muscle fibers of crab (i–iii), and the results obtained were compared with observations (iv) on frog hearts. (i) Microinjected ouabain was dissolved with distilled water or isosmotic potassium glutamate solution. In both cases, ouabain remarkably potentiated both contraction evoked electrically and contractures induced by potassium or caffeine. (ii) Microinjected ouabain increased only the size of a contracture (water-induced contracture) which appeared immediately after the microinjection of distilled water into the fibers, reserpine increased only the duration of the contracture, and caffeine increased both the size and the duration of the contracture. (iii) In crab fibers equilibrated previously with 22Na-containing crab saline solution, extracellularly applied ouabain inhibited both contraction and 22Na efflux from the fibers whereas intracellularly applied ouabain markedly enhanced contraction without a change in the 22Na efflux, (iv) In frog hearts, extracellularly applied ouabain showed a positive inotropic action which was accompanied by occupation of a considerable cellular space by [3H]ouabain and not by a decrease in 22Na efflux. From these results, we concluded that for the appearance of ouabain potentiation the drug must get into the cell and that the potentiation was elicited independent of ouabain-induced inhibition of Na-K-ATPase activity in the muscle. Furthermore, a possible mechanism of the potentiating effect of ouabain on contraction was discussed.

Ouabain potentiation of Ca release from fragmented cardiac sarcoplasmic reticulum from isolated cat heart

The present study was performed to determine the effect of ouabain on Ca release from fragmented sarcoplasmic reticulum (FSR) isolated from cat cardiac muscles. The results clearly demonstrate that ouabain potentiates the Ca release from FSR by changing the ionic environment.

Hypotensive mechanism of adrenergic alpha blockers in cats

The hypotensive mechanism of adrenergic alpha blockers is related to their inhibitory effect on the contractile Ca-mechanism in vascular smooth muscles as in nitroglycerin or verapamil.

[Bilateral direct injury of oculomotor nerves in craniocerebral trauma-report of a case (author's transl)]

A 46-year-old housewife was admitted to the Kawasaki Hospital soon after traffic accident. She was struck in the right forehead. She was very slightly drowsy but well oriented. Both eyeballs were extremely abducted without any motility. The pupils were bilaterally dilated and equal in size with no response to light. There was a pronounced blephaloptosis on both sides. Another neurological abnormality was a slight right facial weakness. On skull films, a linear fracture in the right temporobasal region was noted but the views of the orbits were normal. A lumbal tap showed a mild subarachnoidal hemorrhage. Three weeks after the trauma, pneumoencephalography showed no abnormal finding. Throughout convalescence, no special treatment was given beyond medication. She improved steadily. Three years after injury, re-examination disclosed that lateral gaze was almost full to either side but upward and downward movements of both eyeballs were limited. In our opinion, the most likely cause of the disability in this case was bilateral direct damage of the oculomotor nerves near the petroclinoid ligament (Grüber).

Nutritional requirements for folate compounds and some enzyme activities involved in the folate biosynthesis

Dihydrofolate synthetase activity is widely distributed in various microorganisms and mushrooms. Animals and microorganisms i.e., rat and chicken (in the liver), L. casei and P. cerevisiae, which require essentially pteroylglutamic acid as a nutrient for growth showed no detectable dihydrofolate synthetase activity. S. faecalis R, which can replace pteroylglutamic acid with pteroic acid as a nutrient for growth, had little dihydropteroate synthetase activity but showed normal dihydrofolate synthetase activity. This suggests that the nutritional requirements for folate compounds shown in vivo is in good agreement with the results obtained with dihydropteroate and dihydrofolate synthetase activities in vitro, and that the pathway through dihydropteroic acid as an intermediate is the main route in folate biosynthesis in nature.

[Co-existing aneurysm and arteriovenous malformation--case report (author's transl)]

A patient was presented with both an aneurysm of the frontobasal branch of the right anterior cerebral artery and an arterio-venous malformation fed by the same artery. A 36-year-old man with sudden headache, nausea and vomiting was admitted to the emergency clinic on July, 4, 1974. On admission, he was slightly lethargic and complained of severe headache. The blood pressure was 112 systolic and 64 diastolic. He showed no abnormal findings except for nuchal stiffness and bloody liquor (pressure 260 mmH2o). A right carotid angiogram revealed an aneurysm, 1.0 cm in diameter, on the frontabasal branch of the right anterior cerebral artery and distal to the aneurysm the artery continued to an arteriovenous malformation. No other vascular lesion was observed by other angiographies. On July, 24, 1974, the parent artery (frontobasal branch) of the aneurysm was clipped and the part of right frontal lobe containing the nidus excisted. The patient's post operative course was uneventful.

[Chronic spinal epidural abscess (author's transl)]

A case of 58 year old female with chronic spinal epidural abscess demonstrating rapid progression of complete spinal cord paralysis without remarkable recovery by laminectomy was reported. Patient had a large subcutaneous abscess on left back, ten years ago. Three months before admission she fell down from stairs and had a compression fracture on the seventh thoracic vertebra. She has been troubled with slight spinal ache and left lower back pain since the fall accident. One month before admission she suddenly noted severe lower back pain with radiation to left side and the pain became more severe. Three weeks after she noted fecal retention without urinary retention. Five days before admission she noted gait disturbance accompanied by numbness of both foots. Three days later she developed inability to urinate and the same day, over the coure of a few hours, she became total paraplegia and anesthesia below the waist. On admission neurological examination and myelography disclosed complete spinal subarachnoid block with flaccid total paraplegia and anesthesia below the lower chest. The clinical diagnosis was spinal epidural mass lesion, probably neoplasm. Laminectomy from Th-6 through Th-9 was performed the next day: three days after complete paralysis. The epidural abscess included pus and soft granulation tissue was found and totally removed. Staphylococcus aureus sensitive to penicillin, chloramphenicol etc. was isolated on becteriologic culture. On seven months after operation, sensory and deep reflexes were considrable improved, but she remained paraplegic without sphincter control. Dicussion were made on the incidence, pathogenesis.

Analysis of Hydrostatic Extrusion by the Finite Element Method

An elastoplastic analysis of hydrostatic extrusion is made using the finite element method. The effect of frictional coefficient on the spread of plastic zone, the pressure-displacement curve, and the stress and the strain distributions are studied for the non-steady state in plane-strain and axisymmetric extrusions. Comparisons of results between the finite element solution and slip-line solution and between plane-strain and axisymmetric extrusions are presented. Tensile stresses on the surface of the extruded part behind the die are found to exist. It is also found that the die pressure is high near the die entry and exit and that the surface of the billet in front of the die entry tends to contract.