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Biomedical subjects

M Sakakura

Publications and source records attributed to M Sakakura.

At least 37 records · Page 2Linked to original sources
PubMed1985

Fibrous dysplasia of the skull with increased vascularity in the angiogram.

The case of a 12-year-old girl with fibrous dysplasia involving the cranial vault is presented. The external carotid angiogram demonstrated a dilated and beaded zygomatico-orbital branch of the superficial temporal artery, a faint tumor stain, and an early filling vein. The mass was moderately vascular at the operation and histological examination demonstrated no malignancy.

Cerebral Angiography↗
PubMed1983

Intracerebral hemorrhage remote from the site of the initial neurosurgical procedure.

Four cases of intracerebral hemorrhage remote from the site of the initial neurosurgical procedure are presented. Two of the four patients had preoperative hypertension. Possible mechanisms are discussed, and labile hypertension and unstable blood pressure during the perisurgical period may be contributory. Clinical awareness of this rare but potential complication is essential to early diagnosis and treatment. Difficulty in awakening from anesthesia and the development of new neurological deficits not attributable to the operative site are the most important keys to early diagnosis. Computed tomography is the diagnostic method of choice.

Adult↗
PubMed1982

Diencephalic syndrome of emaciation (Russell's syndrome).

Diencephalic syndrome of emaciation (Russell's syndrome) characteristically presents with the symptoms of marked emaciation in spite of normal linear growth and marked increased of serum growth hormone in infancy and early childhood. It is usually caused by a low-grade glioma, most often an astrocytoma, of the anterior third ventricle including the optic nerve and chiasm. Usually it is not associated with von Recklinghausen's neurofibromatosis. We describe two unusual cases of diencephalic syndrome; one case was caused by a low-grade astrocytoma involving the anterior third ventricle associated with neurofibromatosis, and the other by a malignant astrocytoma of the anterior third ventricle.

Astrocytoma↗
PubMed1982

ACTH content in the anterior pituitary after the infusion of various doses of corticosterone and dexamethasone in normal and adrenalectomized rats.

It is well known that the administration of glucocorticoids inhibits the activities of hypothalamus-pituitary-adrenal axis. The present studies were undertaken to define the site of inhibition of both corticosterone and dexamethasone on this axis in rats. Infusion of 20 or 202 micrograms corticosterone over 6 hr did not change the ACTH content in the anterior pituitary and plasma ACTH levels even through the infusion markedly inhibited the hypothalamic CRF content in normal rats. The constant infusion of a relatively small dose of 20 micrograms dexamethasone inhibited the plasma ACTH level, but not the ACTH content in the anterior pituitary and the hypothalamic CRF content. In contrast to the above results, the infusion of 202 and 504 micrograms dexamethasone over 6 hr increased the ACTH contents in the anterior pituitary, but significantly reduced the hypothalamic CRF content and plasma ACTH levels. These results suggest that the mechanism of dexamethasone inhibition in the hypothalamus-pituitary-adrenal axis is the reduction of ACTH release rather than that of ACTH production in the anterior pituitary.

Adrenocorticotropic Hormone↗
PubMed1981

Degree of inhibition of ACTH release by glucocorticoids in adrenalectomized rats.

The inhibitory effects of corticosterone, dexamethasone and prednisolone on activity of the hypothalamus-pituitary-adrenal axis were investigated in adrenalectomized rats infused with glucocorticoids for 6 h. Infusion of 202 micrograms corticosterone did not inhibit the plasma ACTH concentration, but 504 micrograms corticosterone significantly suppressed plasma ACTH levels. Infusion of 20 micrograms dexamethasone suppressed markedly the plasma ACTH concentration. These data suggest that the degree of inhibition of dexamethasone on ACTH release is about 25 times greater than that of corticosterone. The CRF content of the hypothalamus was not decreased by the administration of 202 micrograms corticosterone over a 6-hour period, but it was significantly diminished by 504 micrograms corticosterone. Infusion of 504 micrograms dexamethasone did not decrease the hypothalamic CRF content; however, infusion of 5 mg dexamethasone effectively suppressed the hypothalamic CRF content. Infusion of 2.5 mg prednisolone did not either decrease the CRF content. These data suggest that the degree of inhibition of natural steroid at the hypothalamus level is stronger than that of synthetic steroids. In rats pretreated with a single injection of dexamethasone (25 micrograms/200 g body weight) 22 h prior to the experiments, continuous infusion of 318 micrograms of dexamethasone significantly suppressed the hypothalamic CRF content, whereas infusion of 504 micrograms of dexamethasone failed to decrease the hypothalamic CRF content in the rats not pretreated with dexamethasone. This finding suggests that a latent period after the injection of dexamethasone is needed for the appearance of the inhibitory action of synthetic steroids at the level of hypothalamus.

Adrenalectomy↗
PubMed1981

The site of inhibitory action of a natural (corticosterone) and synthetic steroid (dexamethasone) in the hypothalamic-pituitary-adrenal axis.

Only a few reports have appeared which have attempted to determine whether the naturally occurring steroid corticosterone, has the same site of action in the hypothalamus-pituitary-adrenal axis as the synthetic steroid, dexamethasone. The present studies help to define the site of inhibition of both corticosterone and dexamethasone on the hypothalamus-pituitary-adrenal axis. Infusion of 20 or 202 microgram corticosterone over 6 h significantly reduced hypothalamic CRF (corticotropin-releasing factor) content, whereas it did not reduce plasma ACTH levels in normal rats. The finding indicates the possibility that the infusion of corticosterone may decrease the hypothalamic CRF content by reducing CRF production or enhancing intracellular and/or extracellular CRF degradation. On the other hand, infusion of 20 microgram dexamethasone for 6 h to normal rats significantly decreased plasma ACTH levels, but did not alter the hypothalamic CRF content. This finding indicates that dexamethasone may inhibit the release and/or production of ACTH in the anterior pituitary. In addition, relatively large doses of corticosterone (504 microgram/rat) and dexamethasone (202 microgram/rat) may suppress CRF content and ACTH release at the level of both the hypothalamus and anterior pituitary.

Adrenalectomy↗
PubMed1979

Craniopharyngioma with midbrain involvement.

An adult patient had a cranlopharyngloma that involved and displaced the midportion of the midbrain, producing Weber's syndrome. Oculomotor paresis in cranlopharyngloma is not always due to parasellar involvement but may be due to midbrain involvement.

Adult↗
PubMed1979

Chondroma of the spine in a newborn infant: case report.

We report a newborn infant with a chondroma of the spine covered by a large lipoma. The child had no neurological deficit. Presenting as a tumor of the back, the chondroma was successfully excised. A review of the pertinent literature emphasizes the rarity of this lesion.

Chondroma↗
PubMed1979

Calcified subdural hematoma in the elderly.

A 71-year-old patient with asymptomatic calcified subdural hematoma is presented. Review of the pertinent literature indicates that the lesion should be left untreated when incidentally found or not associated with progressive neurological symptoms and signs.

Age Factors↗
PubMed1978

The effect of prednisolone and metyrapone on FSH release induced by the administration of LRH.

The response of follicle-stimulating hormone (FSH) to a single injection of synthetic LRH was established in 7 and 6 women following an intramuscular dose of 0.2 mg and 0.1 mg. The secretion of FSH was greater in the group injected with 0.2 mg LRH than in the group injected with 0.1 mg. On the other hand, the response of FSH to a single injection of LRH (0.1 mg/subject) was established in 7 men before and after the pretreatment with metyrapone for one dat (4.5 g/subject). Pretreatment with metyrapone provoked a hypersecretion of FSH following a single injection of synthetic LRH. Seven women, 21--48 years of age who were treated with prednisolone for at least 1.5 months were examined for the responsiveness of the anterior pituitary to a single injection of synthetic LRH (0.2 MG). The secretion of FSH was not suppressed and the maximal serum level of FSH was observed 60 min after LRH injection.

17-Hydroxycorticosteroids↗