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Biomedical subjects

C Yamanaka

Publications and source records attributed to C Yamanaka.

At least 73 records · Page 4Linked to original sources
PubMed1987

Enhancement of transdermal delivery by superfluous thermodynamic potential. III. Percutaneous absorption of nifedipine in rats.

The bioavailability of percutaneous nifedipine was studied in rats. To improve the transdermal delivery of nifedipine, concentration changes due to loss of a volatile component in the vehicle were utilized. The percutaneous absorption of nifedipine was enhanced from binary solvent systems of acetone and propylene glycol (PG) or isopropyl myristate (IPM), compared with the results from simple PG or IPM saturated with the drug. In contrast, no appreciable increases in the percutaneous absorption of nifedipine from PG or IPM above controls were observed for pretreatment of the dosing site with acetone. From a ternary vehicle of volatile/nonvolatile-hydrophile/nonvolatile-lipophile solvent system, i.e., acetone-PG-IPM, a very dramatic enhancement in the bioavailability of nifedipine was noted. In addition, a marked increase in the penetration of PG from the ternary solvent system was found, compared with the result from the binary solvent system of acetone and PG. Nifedipine solutions with the volatile component eventually caused precipitation at the dosing site and so reduced the plasma nifedipine concentration. The precipitation was inhibited or retarded when polymer additives were incorporated in the ternary solvent system, and the high plasma nifedipine concentrations were maintained. This effect was not diminished when the formulation was administered immediately after the evaporation of acetone. The area under the plasma nifedipine concentration-time curve from the ternary solvent system with a polymer additive was higher by about 75 times than that from PG saturated with the drug.(ABSTRACT TRUNCATED AT 250 WORDS)

Acrylic Resins↗
PubMed1987

[Growing aneurysm presenting with Weber's syndrome and obstructive hydrocephalus--a case report].

A case with two cerebral aneurysms, in which one at the origin of the left superior cerebellar artery (SCA) grew and presented with Weber's syndrome and obstructive hydrocephalus, is reported. The patient was a 69-year-old female, who had severe headache and vomited. On admission, neck stiffness was recognized. CT scan showed findings of subarachnoid hemorrhage. Angiograms demonstrated two saccular aneurysms at the right middle cerebral artery (MCA) bifurcation and at the origin of the left SCA. Craniotomy and neck clipping of the aneurysm at the right MCA was performed. After discharge, left oculomotor palsy appeared and gradually progressed. Severe headache and right hemiparesis suddenly occurred two years after the first attack. On the second admission, CT scan revealed high density on the brain surface and a well enhanced round lesion at the left ambient cistern. Left vertebral angiogram demonstrated increase in size of the aneurysm at the left SCA. The patient was discharged after conservative therapy. Drowsiness and urinary incontinence appeared, and she was admitted for the third time three years after the first admission. CT scan showed an enhancing mass lesion sized 25 X 30 mm beside the left midbrain and obstructive hydrocephalus. The aneurysm at the SCA no longer seen on the left vertebral angiogram. V-P shunt was performed. Both Weber's syndrome and obstructive hydrocephalus in this case indicate an aneurysmal natural history, in which aneurysm becomes gigantic and thrombosed spontaneously.

Aged↗
PubMed1986

Cd2+ accommodation by Saccharomyces cerevisiae.

The Cd2+ accommodation mechanism of S. cerevisiae has been examined. In a synthetic medium containing 1 microM CdSO4, cell proliferation was observed following a time lag period of approximately 18 h. During the time lag period, the cell number and viable cell count did not change and the cells did not excrete organic acid as a Cd-chelator, neither did they produce inorganic sulphide in the form of CdS. Whereas approximately 30% of Cd2+ taken up by Cd-accommodated cells was distributed in the cytosol, only a small percentage of Cd2+ was found in the cytosol of unaccommodated cells following 1 h incubation in 1 microM Cd-medium. Furthermore, some Cd2+ in the soluble fraction from Cd-accommodated cells was bound to low molecular weight (less than 30,000) protein(s), while unaccommodated cells only contained small amounts of these proteins. Therefore, it is proposed that Cd2+ binds to the low molecular weight protein(s) present in the cytosol, resulting in a decrease of Cd-toxicity, although the exact mechanism of accommodation is not clear.

Cadmium↗
PubMed1985

[Skull base metastasis of prostatic cancer presenting as exophthalmos--a case report].

A 72-year-old man was admitted to our hospital complaining of diplopia and right exophthalmos. Craniography and CT scan showed thickening of the right orbital roof and no intracranial lesion. Total acid phosphatase and prostatic acid phosphatase were high. Bone scintigraphy revealed high uptake at that lesion and the right pelvis. Unroofing of the right orbit and opening of the optic canal were performed in order to reduce intraorbital pressure. Microscopic examination revealed a metastatic lesion of prostatic cancer. Postoperatively, the patient was treated with "Honvan" and the course has been good.

Aged↗
PubMed1984

[Meningioma and acoustic neurinoma occurring in two siblings of two different families].

The authors reported familial brain tumors in which meningioma and acoustic neurinoma occurred in two siblings of each two families with no evidence of the neurocutaneous syndromes, nor the familial cancer syndromes. Case A-1 is a 49-year-old female admitted to the hospital because of bilateral visual disturbance in July of 1976. A suprasellar mass was observed by CT scan. Right frontal craniotomy and removal of the tumor were done in July of 1976. Histological diagnosis was meningothelimatous meningioma. Case A-2 is a 47-year-old female, a younger sister of case A-1. Tinnitus, hearing disturbance, hemifacial sensory involvement of right side and impaired gait occurred at the end of 1981. Tomography revealed the dilatation of the right internal auditory canal. A multicystic mass was observed at the right cerebellopontine angle by CT scan. An operation was performed in May of 1982, and the tumor was diagnosed as Antoni A type neurinoma. Case B-1 is 23-year-old male who was admitted to the hospital in April of 1975, following the sudden onset of general convulsion. Left carotid angiogram showed the elevation of middle cerebral arteries and a tumor stain at the left temporal region. An operation was performed to remove the left sylvian tumor in April of 1975, and the tumor was diagnosed as transitional meningioma. Case B-2 is a 32-year-old female, an elder sister of case B-1. Bilateral tinnitus and hearing disturbance occurred in 1973. She complained left hemifacial sensory involvement and impaired gait in July of 1979. CT scan showed mass lesions with markedly contrast enhancement effect at the bilateral cerebellopontine angles. An operation was performed to remove the left tumor in November of 1979 and the right tumor in July of 1980. Histologically the both tumors were diagnosed as Schwannoma. The authors have collected reports of 117 families in which intracranial tumors occurred without evidence of the neurocutaneous syndromes and the familial cancer syndromes. Six out of 117 families showed histologically different kind of tumors, however the combination of meningioma and neurinoma could not be found. Consequently our cases of meningioma and neurinoma occurred in two siblings of two different families must be the first report.

Adult↗