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Biomedical subjects

E R Laws

Publications and source records attributed to E R Laws.

300 records · Page 17Linked to original sources
PubMedDate not supplied

MR findings in normal-pressure hydrocephalus: significance and comparison with other forms of dementia.

This study was undertaken to identify findings on magnetic resonance (MR) imaging that might possibly differentiate among several dementia states in the elderly or predict response to shunt therapy in patients with normal-pressure hydrocephalus (NPH). The MR findings were retrospectively reviewed in 54 patients who were divided into four clinical categories: NPH (17 patients), obstructive hydrocephalus (eight patients), Alzheimer disease (eight patients), and non-Alzheimer dementia (21 patients). Three MR findings were evaluated in each case: increased periventricular (PVS) and white matter (WMS) signal on T2-weighted images, CSF flow void sign (CFVS) in the aqueduct, and corpus callosum thinning. Neither the PVS/WMS nor corpus callosum thinning patterns were useful for distinguishing among the four clinical groups. At low field strength, the absence of a marked or moderate CFVS, however, may militate against a diagnosis of NPH. All 17 patients with NPH underwent a shunt procedure after the MR study. A better response to shunt therapy occurred in patients without WMS and with more severe PVS.

Adult↗
PubMedDate not supplied

Stereotactic frame-based error in magnetic-resonance-guided stereotactic procedures: a method for measurement of error and standardization of technique.

When using the stereotactic Leksell G frame for magnetic-resonance-based functional stereotactic lesions, the authors occasionally encountered a situation in which it was not possible to apply the anterior plate of the coordinate box successfully because it came into contact with the anterior posts of the frame; it was noted that the posts as well as the base ring became distorted by the force required to insert the cranial fixation pins. To examine this issue, measurements were taken of the amount of distortion relative to the torque on the screws. It was also found that backward movement of the posterior segment of the base ring indirectly narrowed the anterior spaces for plate insertion. A determination was made that torque over 6 inch pounds caused undesirable contact between the posts and the coordinate box.

Equipment Design↗
PubMedDate not supplied

Anesthesia for transsphenoidal surgery of the hypophyseal region.

For pituitary surgery--by either the transcranial or the transsphenoidal approach--anesthetic management conforms to the general principles of neuroanesthesia as discussed in texts and review articles. In addition, the endocrine functions and the anatomic situation of the pituitary gland must be considered. Preoperative and perioperative evaluation of the patient's endocrine status and appropriate therapeutic measures are important. Preservation of neurohypophyseal function and, frequently, of adequate adenohypophyseal function is an advantage of the transsphenoidal approach to the sella. Potential problems with the transsphenoidal technic include damage to suprasellar and parasellar structures and harzards associated with intraoperative or postoperative bleeding. Anesthetic aspects peculiar to the transsphenoidal approach include positioning of the patient, surgical use of solutions containing epinephrine and topical cocaine, intraoperative air studies, and management of emergence. Anesthesia for the transsphenoidal approach to the sella is discussed on the basis of our experience with 148 surgical procedures in 142 patients.

Adolescent↗
PubMedDate not supplied

Pituitary adenomas producing growth hormone, prolactin, and one or more glycoprotein hormones: a histologic, immunohistochemical, and ultrastructural study of four surgically removed tumors.

The morphologic features of four pituitary adenomas, removed from 2 men and 2 women between 31 and 62 years of age, are reported. The tumors contained growth hormone (GH), prolactin (PRL), and one or more glycoprotein hormones--usually thyrotropin (TSH). Three tumors were associated with acromegaly and one with hyperprolactinemia. Hyperthyroidism was not evident in any of the patients. In the tumors of acromegalic subjects, GH-containing cells were the most numerous, whereas PRL cells were dominant in the adenoma accompanied by hyperprolactinemia. Electron microscopy revealed plurimorphous tumors comprised of various proportions of morphologically different cell types: densely granulated GH cells, TSH-like cells, and the less common mammosomatotrophs and PRL cells. It is suggested that pituitary adenomas producing GH, PRL, and glycoprotein hormones derive from the same precursor; their immunocytochemical profile, fine structural appearance, and endocrine function may depend on the degree and direction of the cellular differentiation.

Adenoma, Acidophil↗
PubMedDate not supplied

Brain tumors.

Brain tumors are a relatively common cancer in all age groups, and the incidence of both primary and metastatic brain tumors is increasing. Fortunately, dramatic advances in methods of diagnosis, surgical technique, and adjuvant therapy have all contributed to an improved outlook for patients with brain tumors. This article reviews the classification, symptoms, diagnosis, and treatment of brain tumors.

Adult↗
PubMedDate not supplied

Central nervous system tumors: what have we learned and where are we heading?

Molecular biology, laboratory and human studies, and clinical trials have furthered knowledge about the pathogenesis, behavior, and treatment of brain tumors. Technical advances such as functional imaging, computer-guided stereotactic surgical devices, and radiosurgery have improved treatment. The future promises continued progress, with the exploration of areas such as new chemotherapy delivery systems, gene therapy, boron capture therapy, and photodynamic therapy.

Adult↗
PubMedDate not supplied

Somatomedin C/insulin-like growth factor I levels after treatment of acromegaly.

An in-house method was used, including dissociation of Somatomedin C/insulin-like Growth Factor I (Sm-C/IGF-I) binding proteins with acid and extraction of Sm-C/IGF-I by C-2 cartridge before radioimmunoassay, to measure plasma Sm-C/IGF-I levels in three groups of patients--total of 19--with acromegaly who underwent transsphenoidal removal of pituitary tumors. In group A (n = 7), the Sm-C/IGF-I levels did not decrease to normal on postoperative day 1 even though the growth hormone concentration had decreased to normal. In group B (n = 4), the Sm-C/IGF-I level decreased to normal in three of the four patients on postoperative day 4, but it remained elevated in one. At two months postoperatively, all four patients had normal values. Group C patients (n = 8) had had an operation two to 23 years previously, and all remained in remission with normal Sm-C/IGF-I levels. Our findings indicate that the Sm-C/IGF-I assay is useful for monitoring acromegaly after transsphenoidal removal of pituitary tumors, but it should be ordered at least four days postoperatively.

Acromegaly↗
PubMedDate not supplied

Pituitary adenoma: a DNA flow cytometric study of 192 clinicopathologically characterized tumors.

A clinically, immunohistochemically and ultrastructurally characterized series of 192 pituitary adenomas was analyzed for DNA content by flow cytometry. Results were assessed not only relative to tumor immunotype, size, and invasiveness, but also with frequency of recurrence. Case selection was non-random; males predominated (1.8:1) and the ratio of macro-to-microadenomas was 4.2:1. Female patients were slightly younger and, in all adenoma categories, less often had invasive tumors: PRL (15%/30%), ACTH (17%/44%), LH/FSH (8%/27%) and null cell adenomas (0%/27%). With the exception of prolactin cell adenomas, similar proportions of macroadenomas and invasive tumors in all tumor subtypes were diploid and non-diploid. Prolactin adenomas differed in that tumors of males showed a high rate of non-diploidy (65%); such tumors were predominantly macroadenomas, but only 28% were invasive. Among GH-containing tumors 78% were macroadenomas, 40% were nondiploid, and the frequency of invasive macroadenomas was higher (49%) than in PRL tumors (21%). ACTH adenomas were mainly microadenomas (81%), their rate invasion (29%) and of non-diploidy being low (14%). Among "non-functioning" (LH/FSH, null cell adenomas), LH/FSH-producing tumors were all macroadenomas, but with low rates of invasion (23%) and non-diploidy (9%). Null cell adenomas, nearly all macroadenomas, had similar low invasion rate (21%), but were more often non-diploid (39%). In all adenoma subgroups S-phase fractions were higher in non-diploid adenomas by an overall ratio of 2.1:1. Prolactin adenomas showed the highest (15.2%) and LH/FSH adenomas the lowest (5.6%) mean S-phase fraction. When compared to long-term follow-up, neither this parameter nor ploidy correlated with tumor size or invasiveness. Lastly, long-term follow-up showed ploidy to be an unreliable predictor of tumor persistence or recurrence.

Adenoma↗
PubMedDate not supplied

MR of the pituitary gland postsurgery: serial MR studies following transsphenoidal resection.

PURPOSE: To determine the MR appearance of the pituitary gland in the early and late postoperative periods in order to distinguish operative complications more effectively and to establish a postoperative baseline. METHODS: Ten patients were prospectively studied with MR following transsphenoidal resection of a pituitary tumor. Early postoperative studies were obtained at 2 to 8 days following surgery, late studies at 4 to 9 months in all patients and also at 12 to 16 months in five. Major observations were height of the pituitary mass and appearance of the surgical packing. RESULTS: Within 8 days following surgery, the height of the pituitary mass was unchanged in two cases, increased in three, and only minimally decreased in five. All decreased in height (average 54%) by 4 to 9 months. Gelfoam packing completely (five) or nearly completely (three) resorbed leaving a normal-size, although deformed, pituitary gland. Fat-packed resection defects persisted (two). CONCLUSIONS: In the early postoperative period, the appearance of the pituitary gland is similar in size to its preoperative appearance. Subsequent involution with packing resorption yields a smaller, deformed pituitary gland.

Adenoma↗