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G T Tindall

Publications and source records attributed to G T Tindall.

At least 55 records · Page 3Linked to original sources
PubMed1982

Supratentorial subarachnoid epithelial cyst: case report and ultrastructural study.

Supratentorial epithelial cysts are rare entities that have evoked controversy regarding their pathogenesis. Recent ultrastructural studies have failed to resolve this controversy. We present a case report and an ultrastructural study of such a cyst. The cyst wall was lined by columnar epithelial cells with prominent cilia and microvilli at their apical surface. They were joined by well-developed junctional complexes and contained abundant intracytoplasmic, electron-dense, granular material, some of which was membrane-bound. These ultrastructural findings suggest that epithelial cysts are derived from elements of the embryological tela choroidea.

Adult↗
PubMed1982

Transsphenoidal microsurgery for prolactin-secreting pituitary adenomas.

The authors present the results of transsphenoidal microsurgery in 100 women with the amenorrhea-galactorrhea syndrome caused by pituitary adenomas associated with hyperprolactinemia (prolactinomas). As the surgical results were closely related to the preoperative levels of serum prolactin, the patients were divided into two groups: patients with preoperative prolactin less than 200 ng/ml (Group 1), and those with preoperative prolactin greater than 200 ng/ml (Group 2). The results in Group 1 (72 patients) were significantly better. In this group, 56 (78%) patients regained normal menstrual cycles, and 55 (76%) had return of elevated prolactin to normal following surgery. In Group 2 (28 patients), however, only 11 (39%) resumed normal menstrual periods postoperatively, and 13 (*46%) had return of elevated prolactin levels to normal. There was good correlation between tumor size and the preoperative level of prolactin. Of the 72 women in Group 1, 58 (81%) had tumors less than 1 cm (microadenomas), whereas of the 28 women in Group 2, only four (14%) had tumors of that size. All patients with visual field deficits preoperatively improved or had a normal visual examination postoperatively; none was made worse by surgery. Four patients (three in Group 2) have required additional surgery and/or irradiation. In the last six patients of the series, contrast-enhanced coronal computerized tomography slices made with the updated General Electric scanner detected five microadenomas. Considering that a relatively high percentage of sellar polytomograms are negative in patients with proven microadenomas (that is, only 40 of 72 patients in Group 1 has abnormal polytomography), it is likely that sellar polytomography will significantly decrease in importance in the diagnostic work-up of these patients. The authors provide a rationale for transsphenoidal microsurgery in these patients as opposed to other forms of management, such as bromocriptine therapy and irradiation.

Adenoma↗
PubMed1981

Transsphenoidal hypophysectomy in disseminated breast cancer.

Sixty patients with metastatic breast cancer had transsphenoidal hypophysectomy at Emory University Hospital. Median survival for the entire group was ten months. Survival was increased (longer than 14 months) in good responders as compared to nonresponders (three months). Pain was significantly relieved in the majority of those patients who had severe pain. Operative complications were minimal. The technic of transsphenoidal hypophysectomy offers a substantial chance of objective and subjective palliation with minimal morbidity in advanced breast cancer.

Adult↗
PubMed1981

Increased LH secretory response to LHRH after hypophyseal stalk-transection of monkeys.

Luteinizing hormone-releasing hormone (LHRH) will evoke large increases of circulating LH in all species tested except for the rhesus monkey. Indeed, in the present study we found that an intravenous injection of a relatively large dose of LHRH (20 micrograms) evoked only a small (2.2-fold) increase in plasma LH levels, as measured by the dispersed interstitial cell bioassay in 4 intact follicular phase monkeys. In contrast, 4 stalk-transected animals exhibited a significantly greater (19.9-fold) increase in plasma LH levels when treated with 20 micrograms of LHRH within 1 week after surgery. Qualitatively similar differences in responsiveness also existed between the two treatment groups with respect to FSH secretion. 2 stalk-transected monkeys treated with LHRH at weekly intervals for the first 4 weeks after surgery showed progressive declines in the LH secretory response approaching, eventually, that observed in intact animals. In 3 additional monkeys, initiation of estrogen maintenance therapy within 3 h of stalk transection, to achieve mid-follicular phase plasma levels of estradiol, totally abolished hyperresponsiveness to LHRH. Thus, the results of this study demonstrate that a transient increase in pituitary responsiveness to LHRH occurs after hypophyseal stalk transection in rhesus monkeys. Although the results indicate that this phenomenon can be accounted for, in large part, by the absence of estrogen feedback, they do not preclude the possibility that factors other than LHRH and gonadal steroids regulate gonadotropin secretion in monkeys.

Animals↗
PubMed1981

Dopamine in hypophysial stalk blood of the rhesus monkey and its role in regulating prolactin secretion.

Numerous studies are suggestive of dopamine serving as the hypothalamic PRL-inhibiting factor in the monkey. In the present study, we measured dopamine concentrations in plasma collected from the hypophysial stalk and determined whether those concentrations were sufficient to account for the inhibiting effect on PRL secretion exerted by the hypothalamus. First, we collected hypophysial stalk blood from seven follicular phase monkeys (four anesthetized with pentobarbital and three with phencyclidine) using a transorbital surgical approach. Dopamine concentrations, measured with a liquid chromatographic-electrochemical procedure, averaged 0.76 ng/ml in stalk plasma and less than 0.1 ng/ml in peripheral plasma collected contemporaneously. Next, we determined the rate of dopamine infusion required to produce peripheral plasma concentrations of dopamine similar to those measured in hypophysial stalk plasma. In seven monkeys, a dopamine infusion rate of 0.1 microgram/kg BW . min produced plasma dopamine concentrations of 0.62 ng/ml, whereas a 10-fold higher rate (1.0 microgram/kg . min) produced plasma concentrations of 1.95 ng/ml. Then, we infused these doses of dopamine into intact follicular phase animals, stalk-transected animals, and estrogen-treated stalk-transected animals to determine their effect on PRL release. The physiological dose of dopamine (0.1 microgram/kg . min) significantly suppressed plasma PRL levels in intact follicular phase animals and estrogen-treated stalk-transected animals but not in untreated stalk-transected animals. The higher rate of dopamine infusion (1.0 microgram/kg . min) was required to inhibit PRL release in the latter group. These results demonstrate that dopamine is secreted by the hypothalamus into hypophysial portal blood in quantities sufficient to account for much of the PRL-inhibiting activity known to be caused by the hypothalamus. Moreover, the results suggest that estrogen reinforces the inhibitory effect of dopamine on PRL release in primates, in contrast to its antagonistic effect in rodents. (Endocrinology 108: 489, 1981)

Animals↗
PubMed1981

Cystic prolactinoma: a variant of "transitional cell tumor" of the pituitary.

Pituitary tumors with features of both Rathke's cleft cysts and adenohypophysial adenomas are extremely rare and have been termed "transitional cel tumors." The ultrastructural features of one of these tumors has been reported, demonstrating cells with features transitional between those of adenohypophysial cells and Rathke's cleft cells, along with other cells with the distinctive features of either cell type. We report a case of a prolactin-secreting "transitional cell tumor" with similar light-microscopic and ultrastructural features. Additionally, the transitional cells in our case exhibited abundant intracellular mucin production. This represents a variant of "transitional cell tumor" of the pituitary gland.

Adenoma↗
PubMed1980

Ultrastructural study of the human neurohypophysis. II. Cellular elements of neural parenchyma, the pituicytes.

The pars nervosa of the neurohypophysis from 12 patients undergoing hypophysectomy for palliative treatment of advanced carcinoma was studied electron microscopically. Special attention was given to the cellular elements, the pituicytes. Five different classes of pituicytes, with various transitional forms, were elucidated based on their ultrastructural characteristics: (1) The most common type, referred to as "major pituicytes", is reminiscent of astrocytes. (2) "Dark pituicytes" are thought to represent different functional stages of the "major pituicytes". (3) "Ependymal pituicytes" are believed to provide ultrastructural evidence that human pituicytes are phylogenetically derived from ependymal cells. (4) "Oncocytic pituicytes" were observed in all cases and are of unknown significane. (5) The ultrastructural features of "granular pituicytes" suggest the existence of an active uptake and catabolism of extracellular material by pituicytes, probably through "ultraphagocytosis" or "endocytosis". These five classes of pituicytes are considered to represent different functional forms of one cell line that originates phylogenetically from the ependyma.

Cell Nucleus↗
PubMed1980

Benign hemangioendothelioma involving the central nervous system: "strawberry nevus" of the neuraxis.

Benign hemangioendothelioma is rarely included in discussions of vascular neoplasms involving the central nervous system, whereas it is a well-defined entity outside the neuraxis. We present four cases of benign hemangioendothelioma, including an infantile hemangioendothelioma with venous drainage into the transverse dural sinus, an intracranial hemangioendothelioma adherent to the falx cerebri, a spinal epidural hemangioendothelioma causing spinal cord compression, and a parasellar hemangioendothelioma. Although hemangioendothelioma resembles hemangioblastoma in some ways, it is a distinct entity differing from the other vascular lesions involving the central nervous system.

Adult↗
PubMed1980

Diagnosis of empty sella syndrome using Amipaque cisternography combined with computerized tomography.

A neuroradiological technique for demonstrating the empty sella syndrome using a low dose of intrathecally injected Amipaque (metrizamide) combined with computerized tomography scanning is described. Two case reports illustrating the potential value of the technique are presented. We have performed 55 cisternograms and have demonstrated the empty sella syndrome in six patients. The procedure is easier to perform and the morbidity is less than in pneumoencephalography.

Adult↗
PubMed1980

Cerebral vasospasm following aneurysm rupture. A protocol for therapy and prophylaxis.

A retrospective study was made of 195 patients who had ruptured intracranial aneurysms without significant intracerebral hematomas and who recovered to at least Grade III by Hunt and Hess' classification. The first 121 patients underwent aneurysm surgery 10 days to 2 weeks after subarachnoid hemorrhage (SAH) without repeat preoperative angiography and without special attention to volume replacement or avoidance of hypotension. Vasospasm resulted in cerebral ischemia in 15% of this group, more than half of these postoperatively, and was treated successfully in half the patients with a combination of aminophylline and isoproterenol. The later 74 patients were managed with aggressive maintenance of normal circulating blood volume and preoperative angiography at 2 weeks following SAH. If significant vasospasm persisted on angiography, surgery was delayed an additional week and, if spasm was still present then, aminophylline and isoproterenol was added prophylactically to aggressive volume replacement before surgery. In this second group of patients, the incidence of clinical vasospasm was essentially unchanged; however, it was almost completely limited to the preoperative period, and was more effectively treated with aminophylline and isoproterenol. Postoperative vasospasm was almost completely eliminated from the second group of patients.

Aminophylline↗