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M Oonuma

Publications and source records attributed to M Oonuma.

4 recordsLinked to original sources
PubMed2001

Extraskeletal osteosarcoma arising in the buttock.

Extraskeletal osteosarcoma is a rare sarcoma that accounts for about 1% of malignant soft tissue tumours. We report an very unusual case of a small-size extraskeletal osteosarcoma arising in the superficial subcutaneous region of the buttock. The patient was a 55 year-old female. She incidentally noticed a small nodule in the right trochanteric region. It was removed under local anesthesia at a private clinic. An additional wide excision was performed at our hospital. There was an 8 mm? 10 mm mass in the subcutaneous tissue. No invasion of the underlying fascia was observed. Microscopic examination of the removed tumour showed bizarre-looking spindle and giant cells with lace-like osteoid. The tumour was diagnosed as extraskeletal osteosarcoma. Chemotherapy with Rosen T-20 was administered to the patient. The patient has survived without recurrence or metastasis for 4 years since the primary surgery. Its superficial location, very small size, wide excision, and chemotherapy were thought to contribute to her long survival.

Buttocks↗
PubMed1991

Strychnine-induced potassium current in isolated dorsal root ganglion cells of the rat.

1. Effects of strychnine (Str) on the dissociated dorsal root ganglion (DRG) cells of the rat have been investigated in whole-cells configuration by a conventional patch-clamp technique. 2. gamma-Aminobutyric acid (GABA)-induced Cl- current (ICl) increased sigmoidally with increasing concentration. The half-maximal response (Ka) was 3 x 10(-5) M and the Hill coefficient was 1.5. Both Str and bicuculline inhibited the GABA-induced ICl in a concentration-dependent manner. 3. Str itself could elicit the current at concentrations over 10(-5) M, at which concentrations the GABA response was completely suppressed. The concentration-response curve for the Str-induced current was bell-shaped, and a nearly maximum response occurred at 3 x 10(-4) M. A transient 'hump' current appeared immediately after the wash-out of external solution containing high concentrations of Str over 3 x 10(-4) M. 4. The Str-induced outward current and a transient 'hump' current were augmented by the removal of extracellular K+ and were suppressed by the substitution of intracellular K+ for Cs+. But the current was not sensitive to extracellular Na+, Ca2+ and Cl-. 5. The reversal potential of Str-induced current (EStr) was -75 mV, which was close to the K+ equilibrium potential (EK = -76.3 mV). The change of EStr for a ten fold change in extracellular K+ concentration was 58 mV, indicating that the membrane behaves like a K+ electrode in the presence of Str. The reversal potential of the 'hump' current was also close to EK. 6. The Str-induced outward current was antagonized by K+ channel blockers such as Ba2+, tetraethylammonium (TEA)-chloride, and 4-aminopyridine (4-AP) in a concentration-dependent manner. 7. The Str-induced K+ current was not affected by internal perfusion of bis(gamma-aminophenoxy)ethane-N, N,N',N-tetraacetic acid (BAPTA), indicating that the Str response does not result in the activation of K+ conductance by the intracellular Ca2+.

Animals↗
PubMed1990

[Photoplethysmograph obtained from a small area of human gingiva].

We have established a method to observe circulation in a small area of the human gingiva. Reflected light photo-plethysmographs (RLP) and transilluminated light photo-plethysmographs (TLP) were recorded from healthy gingiva in 2 young adults of twenties. A tungsten-lamp, connected to a stabilized power source, was used to illuminate the gingiva. The reflected or transilluminated light was collected using a fibre-optic bundle. A CdSe photo-conductive cell was used as the photo-detector. The ECG was recorded simultaneously. The results were as follows: 1) RLP and TLP were both synchronous with the heart beat and showed a dicrotic-notched wave form. 2) When the light-collecting fibre was 0.5 mm from the surface of the gingiva, the dicrotic notch with TLP was clearer than that with RLP. 3) When the light-collecting fibre was placed less than 0.5 mm from the gingival surface, clear dicrotic notches were seen in RLP. 4) When the surface of the gingiva was covered with white opaque paint to prevent transilluminated light, definite dicrotic notches were observed with RLP. 5) RLP was produced mainly by the pulsation of the gingival surface, and the pulsatile movement of the tooth had a little effect on RLP. 6) RLP was consisted from the light reflected from the surface of the gingiva and also from the light reflected after penetrating some distance in the gingival tissue.

Adult↗