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Biomedical subjects

G T Tindall

Publications and source records attributed to G T Tindall.

At least 37 records · Page 2Linked to original sources
PubMed1986

[Pituitary adenoma calcification].

Three hundred and eighteen cases of functioning and non-functioning pituitary adenoma were examined by histological, immunocytochemical and electronmicroscopic technique. Fourty-four of them (13.8%) showed evidence of calcospherites in the tumor tissues. A high incidence of calcospherite is found in functioning adenoma, but not in non-functioning adenoma. Calcification was seen most frequently in cases of prolactinoma (23), GH secreting (7), or GH + PRL tumor (2) and less in adrenocorticotropic hormone secreting adenoma (2) and follicle stimulating hormone secreting adenoma (1). Prolactin and growth hormone might be involved in the control of calcium metabolism. This is because, following adenomectomy in patients with prolactinoma or GH-secreting adenoma with hypercalcemia, there is normalization of serum PRL and GH with reduction in serum calcium. Calcospherite is produced in all of metastatic calcification, arterial calcification, dystrophic calcification and calcinosis. In cases of non-functioning adenoma however, the mechanism is believed to by dystrophic calcification.

Adenoma↗
PubMed1986

[A recurrent case of TSH-PRL secreting microadenoma following hypothyroidism].

A thirty-seven-year-old housewife whose chief complaints were recurrence of galactorrhea and amenorrhea three years after having a selective adenomectomy. Hormonal examination done as a result of the continuation of the endocrinism revealed a hyperprolactinemia and high level of TRH due to hypothyroidism. Serum prolactin responded to neither TSH stimulation nor L-Dopa suppression tests. In addition, serum TSH did not react to TRH test. Contrast enhancement CT showed an intrasellar enhancing mass the size of which was less than 1 cm in diameter. A unilateral septal transsphenoidal operation was performed; and a soft white-yellowish mass 7 X 5 X 5 mm in size was found in the left inferolateral aspect of the pituitary gland. Histological studies of frozen sections of this revealed it to be a pituitary adenoma, with the border between tumor and normal tissue being quite distinct. Immunocytochemical diagnosis further confirmed it to be both PRL and TSH producing adenoma. Electron microscopy showed more than three different hormone-producing cells. The PRL cells contained large, and the TSH cells had small hormone granules; but some tumor cells contained secretory granules of both sizes suggesting production of both PRL and TSH in the cytoplasm. It is necessary in the management of patients like this, during the post-operative period, to adequately institute a thyroid hormone replacement therapy so as to prevent recurrence.

Adenoma↗
PubMed1985

Symptomatic Rathke's cleft cysts located entirely in the suprasellar region: review of diagnosis, management, and pathogenesis.

Three cases of an entirely suprasellar symptomatic Rathke's cleft cyst, two of which were associated with normal sella turcicas, are reported. In all cases, the cysts caused compression of the optic chiasm, and two produced hypothalamic dysfunction. The diagnosis of these entirely suprasellar masses was enhanced by metrizamide cisternography. Two cases were treated by frontal craniotomy and one was treated transsphenoidally, with good results in all cases. The radiology, pathology, and surgical treatment of these unusual cases is presented. An embryological pathogenesis for the occurrence of an entirely suprasellar Rathke's cleft cyst is discussed.

Adolescent↗
PubMed1985

Prolactin-secreting pituitary microadenomas: inaccuracy of high-resolution CT imaging.

Computed tomographic (CT) and surgical findings were correlated retrospectively in 51 patients with preoperative diagnoses of prolactin-secreting pituitary microadenomas. Thirty-nine had microadenomas at surgery. Twenty-three had identifiable discrete lesions. Of these, 21 had microadenomas and two did not; these two groups could not be distinguished reliably. Six patients with proven microadenomas had normal CT scans. Focal hypodense lesions, sellar floor erosion, infundibulum displacement, gland height greater than 8 mm, and an abnormal diaphragma sellae configuration are neither sensitive nor specific findings of microadenoma. A significant number of patients with proven microadenomas had few or none of these abnormalities. Thus, recognition of prolactin microadenoma may not be possible by CT alone, even with high-resolution direct coronal imaging.

Adenoma↗
PubMed1985

Contrast enhancement in CT differentiation between recurrent disk herniation and postoperative scar: prospective study.

Recurrent disk herniation and postoperative scarring are among the major causes of recurrent symptoms after surgery for lumbar disk disease. The myelographic differentiation between these two etiologies is, at best, difficult. To evaluate the role of intravenous contrast enhancement and its impact on making this differentiation using computed tomography (CT), 98 postoperative symptomatic patients were studied prospectively with this technique. Twenty-two patients had subsequent reexploration (23 disk spaces). The unenhanced and enhanced studies of these patients were interpreted independently without surgical information. With contrast enhancement, only three CT studies were considered indeterminate, whereas 10 studies without contrast enhancement were indeterminate. The overall correct diagnosis with contrast enhancement was 17 (74%) of 23, while only 43% of the unenhanced studies yielded the correct diagnosis. Therefore, intravenous contrast enhancement significantly increased the diagnostic accuracy and level of confidence in making the differentiation between recurrent herniated disk and scar.

Cicatrix↗
PubMed1985

Classification and treatment of spontaneous carotid-cavernous sinus fistulas.

An anatomical-angiographic classification for carotid-cavernous sinus fistulas is introduced and a series of 14 patients with spontaneous carotid-cavernous sinus fistulas is reviewed to illustrate the usefulness of such a classification for patient evaluation and treatment. Fistulas are divided into four types: Type A are direct high-flow shunts between the internal carotid artery and the cavernous sinus; Type B are dural shunts between meningeal branches of the internal carotid artery and the cavernous sinus; Type C are dural shunts between meningeal branches of the external carotid artery and the cavernous sinus; and Type D are dural shunts between meningeal branches of both the internal and external carotid arteries and the cavernous sinus. The anatomy, clinical manifestations, angiographic evaluation, indications for therapy, and therapeutic options for spontaneous carotid-cavernous sinus fistulas are discussed.

Aged↗
PubMed1984

Quantitative EEG alterations after isovolemic-hemodilutional augmentation of cerebral perfusion in stroke patients.

Eleven patients with ischemic neurologic deficits in the middle cerebral arterial (MCA) territory and ipsilateral slowing on initial EEG underwent venesection and equal volume replacement with intravenous 5% human serum albumin. As the mean hematocrit was reduced by 19%, the mean cerebral blood flow (CBF) in the MCA territory of the affected and contralateral hemisphere determined by the 133Xenon inhalation technique increased 18 and 21%, respectively. Similarly, CBF in the contralateral occipital region increased 17%. The percentage total slow-wave EEG activity (fractional sum of theta and delta activity, 1.0 to 7.5 Hz) determined by fourier analysis was reduced significantly in the affected MCA territory and in the contralateral occipital region within 1 to 2 hours after isovolemic hemodilution. Using quantitative EEG analysis, rapid improvement in background EEG activity can be demonstrated following the diffuse elevation in CBF by hemodilution.

Brain↗
PubMed1984

Augmentation of cerebral blood flow induced by hemodilution in stroke patients after superficial temporal-middle cerebral arterial bypass operation.

Experimental hemodilutional therapy has been shown to raise collateral perfusion to acutely ischemic brain regions distal to occluded internal carotid (ICA) and middle cerebral (MCA) arteries and to reduce infarct size. Superficial temporal (STA)-MCA anastomosis surgically establishes additional regional collateralization, and this bypass angiographically enlarges over time. Despite bypass patency verification by Doppler recording made at the edge of the craniectomy, the microsurgical STA-MCA anastomosis in 11 stroke patients did not produce early changes in cerebral perfusion parameters in the MCA territory of either hemisphere as determined by 133xenon inhalation. Therefore, hemodilution was initiated in an effort to increase cerebral perfusion during this marginal period when the STA was beginning to dilate progressively. Incremental venesections with equal intravenous volume replacement with 5% human serum albumin caused a significant lowering of the hematocrit from 40 +/- 1 to 33 +/- 1%. This isovolemic hemodilutional therapy resulted in significant mean regional cerebral blood flow (rCBF) elevations of 23 +/- 5% (SE) in the bypassed MCA territory and of 25 +/- 6% in the opposite MCA region. The mean gray flow (F1) in the involved and homologous MCA regions significantly increased 27 +/- 8% and 30 +/- 11%, respectively. Similarly, the initial slope index (ISI2) significantly rose by 17 +/- 5% in the bypassed MCA territory and by 18 +/- 6% in the homologous region. These data objectively support the premise that reductions in hematocrit without intravascular volume expansion augment cerebral blood flow, probably by reducing blood viscosity.(ABSTRACT TRUNCATED AT 250 WORDS)

Brain↗
PubMed1984

Clinical and pathological effects of bromocriptine on prolactin-secreting and other pituitary tumors.

Bromocriptine inhibits prolactin secretion and causes size reduction of prolactin-secreting adenomas. The effect of the drug upon pituitary tumors other than prolactinomas is uncertain. The authors report a prospective series of 12 patients with pituitary macroadenomas in whom bromocriptine was administered for 6 weeks prior to transsphenoidal surgery. Five of the patients had computerized tomographic documentation of significant reductions in tumor size (Group A) and six had no change (Group B) during 3 and 6 weeks of bromocriptine administration. One patient who demonstrated size reduction in his tumor was not assigned to either group as he was treated with high-dose dexamethasone concurrently with the bromocriptine. Pathological examination (light and electron microscopy and immunocytochemistry) indicated that all Group A patients harbored tumors with prolactin granules whereas all Group B tumors lacked such granules. Adenoma cells in the responsive tumors were involuted with reduced cytoplasmic, nuclear, and nucleolar areas. Neither widespread cell necrosis, infarction, nor vascular injury was observed. Two of the five Group A patients discontinued bromocriptine prior to completion of the 6-week protocol and had a rapid return of their tumors to pre-treatment size. Although bromocriptine has been reported to cause shrinkage of nonfunctional tumors, there was no radiological evidence of size reduction or pathological changes in the nonfunctional tumors of this series. Interestingly, serum levels of prolactin were modestly elevated (84 and 113 ng/ml) in two of the six Group B patients, an elevation due to stalk compression rather than secretion by adenoma cells. This finding underscores the fact that failure of bromocriptine to reduce pituitary tumor size in the presence of hyperprolactinemia may occur because the tumor is other than a prolactinoma. This is the first moderate-sized group of patients in whom pathological changes in responsive prolactinomas during bromocriptine therapy have been demonstrated. As bromocriptine is not tumoricidal, and thus not curative, there is insufficient evidence to recommend this drug as primary therapy for either prolactin-secreting or nonfunctional macroadenomas, but the drug may have potential as a preoperative adjunct to effect shrinkage of prolactinomas and theoretically, at least, make excision easier and possibly more complete.

Adenoma↗
PubMed1984

The use of greater omentum vascularized free flaps for neurosurgical disorders requiring reconstruction.

The heterotopic transfer of composite tissue, with microvascular anastomosis of an arterial supply and venous drainage to locally existing vessels, has received considerable attention in the plastic surgical literature. The use of latissimus dorsi musculocutaneous free flaps has been reported in the repair of large defects of the scalp, cranium, and dura following resection of invasive neoplasms or trauma. When the defect involves primarily subcutaneous tissue loss resulting in abnormal contour, omental free flaps provide effective coverage and restoration of contour. In addition, the inherent capability of the omentum to combat infection and form an ideal bed for the establishment of skin or bone grafts provides further indications for its use. The authors have used omental free flaps in nine cases to reconstruct gunshot wounds of the head, orbit, and face, heal chronic cavitating frontal sinus infections, form a base over exposed dura for reconstruction of the skull with rib grafts, and cover large defects after resection of invasive tumors or infected scalp. These wounds of neurosurgical interest were reconstructed with acceptable structural and aesthetic results. The indications, surgical techniques, results, alternative procedures, and potential complications of this procedure are discussed. The authors believe that omental free flaps should be considered an option in the armamentarium of reconstructive approaches for skull, dural, scalp, orbital, and facial wounds.

Adult↗
PubMed1984

Cushing's disease associated with an intrasellar gangliocytoma producing corticotrophin-releasing factor.

A 58-year-old woman had Cushing's disease with elevated plasma adrenocorticotrophin and an intrasellar tumor. Light microscopy showed that the tumor was a gangliocytoma containing immunoreactive corticotrophin-releasing factor accompanied by pituitary corticotroph hyperplasia. Ultrastructural examination identified an intimate association and desmosomal attachments between interdigitating cell processes of neurons and corticotrophs. It is suggested that Cushing's disease was due to the effect of corticotrophin-releasing factor on corticotrophs; this case represents a syndrome supporting the concept that, in some patients, Cushing's disease may have a hypothalamic origin.

Corticotropin-Releasing Hormone↗
PubMed1983

Evaluation of transsphenoidal hypophysectomy in the management of patients with advanced malignant melanoma.

Transsphenoidal hypophysectomy was performed in 13 patients with advanced malignant melanoma. Although three minor responses were observed, there were no complete or partial responses. All three patients with bone pain had a decrease in discomfort lasting 1-2 months. All five patients with minor responses or stable disease had postoperative decreases in the excretion of the dihydroxyphenylalanine (DOPA) metabolite 3-O-methyldopamine; all but one patient with clinical progression had postoperative increases in excretion. Average survival of those whose postoperative excretion fell (143 +/- days; range, 60-217+) was significantly longer (P less than 0.004) than that of those whose postsurgical values rose (30 days; range, 15-58).

Adult↗
PubMed1983

Persistence of beta-endorphin in human cerebrospinal fluid after hypophysectomy.

beta-Endorphin immunoactivity was measured in the plasma and cerebrospinal fluid (CSF) of 13 patients with metastatic cancer 1 day before and 5 days after complete transsphenoidal hypophysectomy. Preoperatively, mean beta-endorphin-like immunoactivity in plasma was 18.2 +/- 3.5 pg/ml (SEM) and in CSF 32.3 +/- 6.3 pg/ml. No correlation was noted between the concentration of beta-endorphin in plasma and CSF. Postoperatively, plasma beta-endorphin was undetectable (less than 7 pg/ml) in 12 patients and was low (9.6 pg/ml) in 1 patient. In CSF, however, beta-endorphin was detectable in 10 of the 13 patients postoperatively, with a mean of 14.0 +/- 2.2 pg/ml. Chromatography on Sephadex G-50 of CSF extracts pooled from 3 patients after hypophysectomy showed that the majority of beta-endorphin immunoactivity eluted in the same position as synthetic human beta-endorphin. We conclude that beta-endorphin becomes undetectable in plasma after hypophysectomy in patients receiving exogenous glucocorticoid replacement but remains detectable in significant amounts in CSF. It appears, therefore, that a considerable portion of the beta-endorphin in CSF is of nonpituitary origin, most likely resulting from synthesis and secretion of this peptide by brain directly into the CSF.

Adult↗
PubMed1983

Effects of intravenous nitroglycerin on the intracranial pressure and volume pressure response.

Ventricular fluid pressure (VFP) and volume-pressure response were measured during nitroglycerin (NTG) infusion in nine patients anesthetized with N2O and fentanyl. The patients' ventilation was controlled, and PaCO2 was kept at 32 +/- 4 mm Hg. When an infusion of 0.01% NTG was given intravenously to decrease the mean blood pressure to 95.1%, 84.7%, and 78.2% of control, the VFP increased from control levels of 9.94 +/- 2.14 mm Hg to 12.89 +/- 2.25, 15.6 +/- 2.85, and 14.43 +/- 3.45 mm Hg, respectively. The volume-pressure response showed a significant increase when blood pressure decreased to 84.7% and 78.2% of control. These results suggest that intravenous NTG caused an increase in the intracranial pressure and a decrease in the intracranial compliance.

Adolescent↗