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Biomedical subjects

E R Laws

Publications and source records attributed to E R Laws.

At least 199 records · Page 11Linked to original sources
PubMed1985

CT of the sella turcica after transsphenoidal resection of pituitary adenomas.

A retrospective review of 120 patients undergoing transsphenoidal surgery for pituitary adenomas revealed that computed tomography (CT) was less sensitive and less specific than hormonal methods in identifying residual functioning adenomas. However, CT was the only useful method of evaluating nonfunctioning tumors, including pseudo-prolactinomas. Enlargement of the pituitary stalk, when seen on preoperative CT, was 100% predictive of "cure" if the enlargement returned to normal size on a remote follow-up scan (n = 8) and was 100% predictive of residual tumor if the enlargement persisted or evolved (n = 8). Resolution of stalk displacement was the next most reliable predictor of cure (91%, n = 11), but persistent displacement was less reliable than abnormal intrasellar enhancement in predicting the presence of residual tumor (71%, n = 28, vs. 81%, n = 26). Enhancement in the postoperative sella by other than normal pituitary gland was presumed to be due to inflammation in 19% of patients. Inflammatory enhancement was observed in the presence of autograft and homograft muscle plugs and, unlike enhancement due to untreated tumors, was observed to decrease in size and intensity with time. Intrasellar enhancement was an unreliable criterion of success or failure in cases of microadenoma. All 14 patients with functioning adenomas and preoperative parasellar tumor extension had persistent tumor at postoperative evaluation. Of the 47 patients with resected functioning adenomas who had CT scans showing empty or partly empty sellas after operation, 22 (47%) had hormonally detectable residual tumor.

Adenoma↗
PubMed1985

The pathogenesis of acromegaly. Clinical and immunocytochemical analysis in 75 patients.

A series of 75 patients with acromegaly and immunocytochemically characterized pituitary adenomas has been analyzed. Tumors secreting growth hormone (GH) only were found in 21% of cases. The remainder had tumors immunoreactive for more than one pituitary hormone: GH and prolactin in 31%; GH, prolactin, and glycoprotein in 40%; and GH and glycoprotein in 8%. Microadenomas were surgically treated in 17 patients with a success rate of 82%. Overall, normalization of basal GH secretion (to less than or equal to 5 ng/ml) was achieved in 54% of cases. The implications of these findings for the pathogenesis and neurosurgical management of acromegaly are discussed.

Acromegaly↗
PubMed1985

Transsphenoidal surgery following unsuccessful prior therapy. An assessment of benefits and risks in 158 patients.

The authors report the results of a retrospective study conducted in an effort to define the results and risks of transsphenoidal surgery for patients whose prior therapy had failed. In a series of 1210 patients undergoing transsphenoidal surgery during a 10-year period, 158 had received prior therapy: 127 for pituitary adenoma, 20 for craniopharyngioma, and 11 for other lesions. Prior therapy was considered "direct" when it consisted of craniotomy or transsphenoidal surgery (either open or stereotaxic), and "indirect" when it consisted of radiation therapy, adrenalectomy, or bromocriptine therapy. The current transsphenoidal operation was performed for persistent hyperfunctioning endocrinopathy in 63 patients, for visual loss in 72 patients, and for cerebrospinal fluid (CSF) rhinorrhea in 21 patients. Success rates were as follows: normalization of endocrinopathy was achieved in 35% of cases; improvement or stabilization of vision in 59%; and successful repair of CSF rhinorrhea in 74%. The risks associated with repeat transsphenoidal surgery are significantly greater than the same procedure in a previously untreated patient.

Adenoma↗
PubMed1985

Metastasis to pituitary adenoma.

Neoplasm to neoplasm metastasis is a medical curiosity. We report two cases of adenocarcinoma metastatic to pituitary adenoma. In both, abrupt progression of symptoms referable to the sellar region was noted and followed by the death of the patient.

Adenoma↗
PubMed1985

Magnetic resonance imaging vs. computed tomography: advantages and disadvantages.

Magnetic resonance imaging (MRI) of the head and spine exceeds the sensitivity of computed tomography (CT) in detecting parenchymal lesions of the brain and spinal cord. MRI should be employed as a screening examination, particularly in patients suspected of having demyelinating diseases. CT continues to be the imaging technique of choice in evaluation of trauma, accurately depicting bony abnormalities and intracranial hemorrhage in evaluation of the spinal column and suspected disc herniation and in uncooperative patients.

Astrocytoma↗
PubMed1984

Surgical management of pituitary adenomas.

As experience with endocrine diagnosis, radiologic evaluation, and transsphenoidal microsurgery has accumulated, more effective therapy has become available for patients with pituitary adenomas. The amelioration of the various endocrinopathies and the potential for restoration of vision in patients with visual impairment make this aspect of modern neurosurgery most satisfying, both for the patient and for the surgeon.

Acromegaly↗
PubMed1984

Human brain phenol sulfotransferase: biochemical properties and regional localization.

Phenol sulfotransferase (PST) catalyzes the sulfate conjugation of catecholamines and phenol and catechol drugs. The human blood platelet contains a thermolabile (TL) form of PST that catalyzes the sulfate conjugation of dopamine and other monoamines and a thermostable (TS) form that catalyzes the sulfate conjugation of micromolar concentrations of phenol and p-nitrophenol. Experiments were performed to determine whether the brain contains forms of PST analogous to the TL and TS forms found in the human platelet, and to determine whether there are regional variations in human brain PST activity. We found that the human brain contains at least two forms of PST, forms that are similar to the platelet TS and TL forms of the enzyme with respect to substrate specificity, apparent Km constants, thermal stability, and sensitivity to inhibitors. Optimal conditions were determined for the measurement of these two activities in brain homogenates. The stability of PST activities in the human brain after death was determined in five samples of cerebral cortex that were obtained during clinically indicated neurosurgical procedures. An average of 76 +/- 8% and 80 +/- 9% (mean +/- SEM) of the basal TL and TS PST activities, respectively, remained in these five samples of cerebral cortex after 8 h of storage under simulated post-mortem conditions. Six human brains were then obtained less that 8 h after death from patients who had no neurological disease prior to death. The mean activities of the TL and TS forms of PST were measured in 17 different regions of the six brains. If the pituitary was excluded from consideration, TL and TS PST activities both varied approximately fivefold among these regions, and both activities were highest in cerebral cortex. However, the average TS activity in the anterior pituitary, a tissue of non-neural origin embryologically, was 6.5-fold greater than the highest average TS PST activity found in cerebral cortex.

Arylsulfotransferase↗
PubMed1984

A case for hypothalamic acromegaly: a clinicopathological study of six patients with hypothalamic gangliocytomas producing growth hormone-releasing factor.

We report the histological, ultrastructural, and immunocytochemical features of six hypothalamic gangliocytomas associated with pituitary GH cell adenomas and/or acromegaly. In four patients, the gangliocytoma was intrasellar, and no hypothalamic investigation was performed; in two patients, autopsy confirmed hypothalamic involvement. Four patients had a gangliocytoma associated with pituitary GH cell adenoma and acromegaly; electron microscopy demonstrated an intimate association between neurons and adenomatous GH cells. One patient had a gangliocytoma and a GH cell adenoma but no clinical evidence of acromegaly. In the sixth patient, clinical and biochemical acromegaly was manifest, but no pituitary adenoma was demonstrated. Using immunocytochemistry, human pancreatic tumor GRF (hptGRF-40) was localized in the majority of neurons of all six gangliocytomas. The pituitary adenomas and nontumorous adenohypophyses were negative for hptGRF-40. In addition, somatostatin, glucagon, and GnRH were demonstrated within some neurons of several tumors; insulin and gastrin stains were equivocal. These findings confirm previous proposals of production of a GRF by such gangliocytomas. While the significance of other peptides found in some of the tumors is uncertain, the presence of hptGRF-40 in neurons of these gangliocytomas supports the theory that GRF excess is the mechanism responsible for over-production of GH and provides evidence for a syndrome of hypothalamic acromegaly.

Acromegaly↗
PubMed1984

Erythrocyte catechol-O-methyltransferase, platelet monoamine oxidase, and platelet phenol sulfotransferase activities in patients with prolactin-secreting pituitary adenomas.

Dopamine is metabolized by oxidative deamination catalyzed by monoamine oxidase, O-methylation catalyzed by catechol-O-methyltransferase, and sulfate conjugation catalyzed by phenol sulfotransferase. This study was performed to determine whether platelet monoamine oxidase, red blood cell catechol-O-methyltransferase and platelet phenol sulfotransferase enzymatic activities in patients with prolactinomas were quantitatively different from the same enzyme activities in blood samples from normal subjects. The mean enzyme activities in blood samples from 22 women with histologically proven prolactinomas were compared to the mean enzyme activities in blood samples from 32 normal women. The blood levels of these 3 enzymatic activities were not significantly different between the two groups (P greater than 0.4). If the regulation of these catecholamine-metabolizing enzyme activities in blood elements reflects the regulation of the enzymes in the hypothalamic-hypophyseal region, these results suggest that a defect in the regulation of dopamine-metabolizing enzymes is not associated with the pathogenesis of prolactinomas.

Adenoma↗
PubMed1984

Incidence of skull fractures in Olmsted County, Minnesota.

Between 1935 and 1974, 3598 episodes of head trauma among Olmsted County, Minnesota, residents resulted in 1097 skull fractures. Of these, 53% were simple, 16% were depressed, 12% were compound, and 19% were basilar. The age-and sex-adjusted incidence of skull fractures was 44.3 per 100,000 person-years overall, was somewhat greater in the urban than in the rural areas of Olmsted County, and was relatively stable for the final 30 years of the study. Age-specific incidence rates were highest for the very young, and simple linear fractures were the predominant type of skull fracture in this age group and among the elderly. The male:female ratio of incidence rates varied from 2.1:1 to 4.5:1 depending on fracture type. Motor vehicle accidents accounted for 38% of the skull fractures and were a particularly important cause among young males. Falls accounted for 37% of the skull fractures and were the major cause of fractures in the elderly and pediatric age groups. The results of this population-based study may be helpful in formulating recommendations for the evaluation and management of head-injured patients.

Adolescent↗
PubMed1984

Neurosurgical management of low-grade astrocytoma of the cerebral hemispheres.

The authors conducted a retrospective review of surgically treated, histologically proven cases of low-grade (Grade 1 or 2) astrocytomas. Follow-up analysis, with survival time as the end-point, was completed using multivariant statistical analysis. In the 461 cases of supratentorial low grade astrocytoma in this study, age of the patient at the time of surgery was by far the most important variable in predicting length of survival. Other variables correlating with increasing survival times were: gross total surgical removal, lack of major preoperative neurological deficit, long duration of symptoms prior to surgery, seizures as a presenting symptom, lack of major postoperative neurological deficit, and surgery performed in recent decades. The multi-variant regression analysis showed that radiation therapy was of clear benefit, primarily in older patients with incompletely removed tumors. For purposes of establishing prognosis and testing the results, a "score" was developed to predict survival times, based on the most important variables. The data in this study provide a basis for the analysis of future modes of management of low-grade gliomas.

Adolescent↗
PubMed1984

Parameters of hematoporphyrin derivative tumor cell killing efficiency: decomposition of hematoporphyrin derivative at high power densities.

Hematoporphyrin derivative (HpD) tumor cell killing efficiency has been evaluated as a function of power density, optical spectrum, HpD concentration, and HpD preparation using trypan blue exclusion assay. Cell survival curves for Mayo Clinic HpD and for Photofrin were equivalent at all concentrations and power densities for both violet and red light. Survival curves for red light demonstrated a two-fold increased cellular killing efficiency at higher densities (160 mW/cm2). However, for violet light an irreversible and marked decrease in cellular killing efficiency was found as the power density was increased. This phenomena of decreased cellular killing efficiency of violet light at high power densities is consistent with a process of photo-decomposition of HpD and is most pronounced at low concentrations (less than 25 micrograms/ml).

Cell Survival↗
PubMed1984

Hearing preservation after removal of acoustic neurinoma.

Between January 1, 1978, and July 1, 1983, 149 patients underwent acoustic neurinoma removal (151 procedures). Of these, 119 ears (118 patients) had had some degree of hearing on the affected side preoperatively, and in all of them the tumors had been removed by a posterior cranial fossa approach. Fourteen (12%) had measurable hearing preserved postoperatively--serviceable in eight ears and poor in six. The patients with preserved hearing had had their hearing loss for a shorter period, slightly better preoperative hearing levels, and a smaller tumor. The complications, morbidity, and mortality in this group were comparable to those in other series. It is concluded that preservation of hearing is a worthwhile goal that can be achieved without increased risk.

Female↗