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At least 289 records · Page 16Linked to original sources
PubMed1978

The sublabial transseptal transsphenoidal approach to the hypophysis.

A simple and safe technique for the sublabial transseptal transsphenoidal approach to the hypophysis and parasellar region is described. A review of the literature reveals that this technique and other transsphenoidal routes to the hypophysis were performed more than half a century ago.These procedures fell into disfavor because fo low magnification and insufficient illumination of the operative field, infection and inadequate postoperative endocrine replacement therapy. With today's antibiotic therapy and hormonal replacement, plus the use of the operating microscope, the transsphenoidal route to the hypophysis has gained renewed interest among neurosurgeons and otolaryngologists. Each of the transsphenoidal routes and the advantages of the "from below" approach are described. The applications of transsphenoidal approach and the nonsurgical modalities for hypophysectomy are reviewed. The simplicity and safety of the sublabial transseptal transsphenoidal approach depend on a thorough familiarity with the surgical anatomy, proper positioning of the patient, and the availability of appropriate instrumentation. Photographs of specially prepared whole head anatomical specimens plus skull dissections with radiographic correlation illustrate the pertinent anatomy. Some of the vital structures to be identified and avoided are the optic canals, carotid arteries, circular sinuses, cavernous sinuses, III, IV, V, VI cranial nerves, foramen rotundum, medial walls of the orbits, medial walls of maxillary sinuses, medial pterygoid plates and pterygoid canals. A method for preoperative determination of key distances within the patient's skull is described along with other preoperative tests. This paper discusses the self-retaining speculum and other new instruments for this procedure. A gauge mounted on the front end of the speculum is calibrated to measure the size of the opening at the tip of the speculum. Thirty cases are included in this report, six of which are presented in detail. No operative mortality, CSF rhinorrhea, visual damage carotid or cavernous sinus hemorrhage fracture of the medial pterygoid plates or maxilla were encountered in this series. Three patients developed diabetes insipidus and two patients had meningitis which responded to antibiotic therapy.

Breast Neoplasms↗
PubMed2001

Differential radiosensitivity of hypothalamo-pituitary function in the young adult rat.

Cranial irradiation in children and adults often results in irreversible hypopituitarism. The earliest and most common endocrine abnormality is GH deficiency, often followed by other pituitary hormone deficits. We investigated whether a similar pattern of progressive hypopituitarism could be reproduced in an animal model. Different doses of cranial irradiation were delivered to the hypothalamo-pituitary region of normal adult male rats, and the effects on their subsequent growth, pituitary weight and hormone contents were studied. Animals received cranial irradiation with 300 kV X-rays at doses of 0, 20, 22 or 24 Gy (n=15 per group) and five animals from each group were killed at 8, 14 or 20 weeks after irradiation. Their anterior pituitary glands were weighed and assayed for GH, LH, TSH, ACTH and prolactin (PRL) content. All three doses of irradiation reduced body weight compared with that in non-irradiated controls and compromised growth between 8 and 20 weeks. Pituitary weight increased between 8 and 20 weeks in control rats, whereas it decreased significantly in the irradiated animals. Irradiation induced time- and dose-dependent changes in pituitary hormone contents. GH and PRL were most sensitive and decreased by more than 90% after irradiation; TSH contents were unaffected 8 weeks after the lowest dose of irradiation, but were reduced at 14 and 20 weeks. LH and ACTH were the slowest to be affected, and only at the greater doses of radiation. Thus progressive multiple pituitary endocrine deficits can be induced differentially in rats by increasing doses of cranial irradiation. This model should prove useful for defining the sites and mechanisms by which cranial irradiation induces neuroendocrine dysfunction.

Animals↗
PubMed1979

Cyclic GMP and cyclic AMP levels in median eminence, hypothalamus and pituitary gland of the rat after decapitation or microwave irradiation.

Cyclic AMP and cyclic GMP content of the median eminence (ME), medial basal hypothalamus (MBH), posterior pituitary (PP) and anterior pituitary (AP) of inact male rats was measured by radioimmunoassay following decapitation or exposure to microwave irradiation (MW). Levels of both nucleotides in MW irradiated animals were higher in all three nervous tissues studied than in the AP. Following decapitation cyclic AMP levels increased strikingly in the MBH and ME, slightly in the AP, but remained unchanged in the PP. Cyclic GMP levels increased more markedly in the ME than in the MBH, slightly in the PP and did not change in the AP. The distinct synthesizing capability of the cyclic AMP and cyclic GMP generating systems in the ME, a region rich in neurohormones known to control anterior pituitary function, raises the possibility that these nucleotides are involved in the process of neurohormone secretion by the ME.

Animals↗
PubMed1986

Cushing's disease coexisting with a single macronodule simulating adenoma of the adrenal cortex.

A rare case of Cushing's disease coexisting with a single macronodule simulating adenoma of the adrenal cortex is presented. The basal and dynamic tests supported the diagnosis of Cushing's disease, whereas the CT-scan, ultrasound and iodocholesterol uptake were suggestive of a left adrenal adenoma. Treatment consisted of extirpation of the nodular gland followed by pituitary irradiation. The examination revealed a single macronodule with no histological membrane, surrounded by hyperplastic adrenocortex. Together with the three similar ones reported in the literature this case suggests that nodular hyperplasia may be an intermediary stage between diffuse hyperplasia and the appearance of an autonomous adenoma after long-term stimulation of the hyperplastic gland.

Adenoma↗
PubMed2003

Effect of gamma irradiation on magnesium content in rat tissues.

Studies in the field of radiation chemistry have shown that the greatest damage induced by ionizing radiation appears as a consequence of uncontrolled production of free radicals in the living organism, which have their origin in oxidative stress induced by ionizing radiation. Ionizing radiation also has an influence on the content of bio-essential elements in mammalian tissues. Analysis of the concentration of magnesium (Mg) seven days after whole body irradiation with a single dose of 4.2 Gy of gamma rays from a 60Co source, showed a slight reduction in Mg content in the following analyzed tissues: front brain (cerebral hemispheres with underlying structures except pituitary gland and hypothalamus) and adrenal glands from irradiated animals as compared to the non-irradiated controls, this difference however being not statistically significant. No significant differences in the content of Mg were detected in the pituitary glands between the two groups of animals. In contrast, a significantly higher concentration of Mg seven days after irradiation was measured in the hind brain-containing cerebellum with lateral lobes and flocculi (p < 0.005), hypothalamus (p < 0.0001) and testes (p < 0.05) of irradiated animals, when compared to the non-irradiated controls. This accumulation of Mg, in particular tissues of the Central Nervous System (CNS) and endocrine glands regulated by the pituitary gland and hypothalamus, may indicate the differential role Mg++ ions have in keeping the homeostasis of certain tissues, those of the brain, adrenal glands and testes after exposure to ionizing radiation.

Animals↗