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Biomedical subjects

W Saeger

Publications and source records attributed to W Saeger.

At least 163 records · Page 9Linked to original sources
PubMed1984

A rater training program in removable prosthodontics.

Four faculty members in removable prosthodontics participated in a three-phase rater training program. Nine complete dentures were given an overall rating by three outside experts to obtain an accuracy measure. A three-point rating scale was used: R (cannot be appreciably improved), S (clinically acceptable), and T (clinically unacceptable). During the pretraining phase, the average interrater reliability was .57 as estimated by intraclass correlation, and the mean accuracy correlation was .76. The rater training phase consisted of a four-hour session including presentations and discussions of rating terminology and formats, observer accuracy, and related issues. In the post-training phase, the same nine complete dentures were rated by the four faculty members, using the same three-point rating scale and a five-point scale. The average post-training interrater reliabilities were .56 and .76 on the three- and five-point scales, respectively. The mean accuracy correlation was .78.

Denture, Complete↗
PubMed1983

Pituitary hyperplasia. Definition, light and electron microscopical structures and significance in surgical specimens.

Surgical specimens of 15 normal and 106 para-adenomous anterior pituitaries were studied immunocytochemically and in part electron microscopically for the presence of hyperplasia. GH cell hyperplasia was found in 13% of all normal pituitaries, in 6% of the cases with Prolactin secreting adenomas and in 9% of the cases with ACTH secreting adenomas. Prolactin cell hyperplasia occurred in nearly equal percentages (17-23%) in normal pituitaries and in areas adjacent to GH-, Prolactin- or ACTH-secreting adenomas or adjacent to inactive adenomas. Previous findings of relatively more frequent Prolactin cell hyperplasia occurring together with Prolactin producing adenomas have to be revised. Prolactin cell hyperplasia as a primary source of hyperprolactinemia is very rare and almost always occurs in conjunction with oncocytic adenomas. ACTH cell hyperplasia was found in 13% of the normal pituitaries, in 14% of the cases with Prolactin secreting adenomas, in 58% of the cases with ACTH producing adenomas and in 40% of the pituitaries with GH secreting adenomas. We have no explanation for the latter result. ACTH cell hyperplasia may be the primary cause of Cushing's disease (18% of all Cushing cases). Hyperplasia of TSH cells in normal pituitaries was rare (7%) and with the exception of Prolactin producing adenomas (22%) was not found near adenomas. Clinical-pathological correlations are discussed.

Adrenocorticotropic Hormone↗
PubMed1983

In vitro secretion of adenoma and anterior lobe cells in two typical cases of Cushing's disease.

Fragments of adrenocorticotropic hormone (ACTH) cell adenomas and anterior lobes of two patients with Cushing's disease were obtained by transnasal operation. Both patients showed the typical clinical course, with postoperative ACTH deficit and all other pituitary functions intact. Equivalent specimens of tissue were investigated by immunocytology and in a superfusion system. The majority of adenoma cells were ACTH-positive, whereas ACTH-secreting cells of the anterior lobes were mostly inactive and were reduced in number. In vitro, adenomatous tissue showed high ACTH secretion into the superfusion medium, which was increased significantly after vasopressin application. Corticoid feedback was impaired Anterior lobe cells exhibited a significant spontaneous ACTH secretion that was reduced by cortisol, but not stimulated by vasopressin. These results support the concept of an impaired corticoid feedback at the adenoma level in the presence of suppressed ACTH secretion of the para-adenomatous anterior lobe.

Adenoma↗
PubMed1982

Pituitary adenomas with hyperfunction of TSH. Frequency, histological classification, immunocytochemistry and ultrastructure.

In a collection of 564 surgically removed pituitary adenomas, 4 cases werefound to have had elevated TSH plasma levels. One of these tumors )(case 1) could be classified as a highly differentiated mucoid TSH cell adenoma presenting histochemical reactions typical of, as well as electron microscopical features identical to, normal TSH cells. Immunoenzymatic studies failed to dfemonstrate TSH in the tumor cells. Two further adenomas (case 2 and 3) were similarly structured in many areas, but showed regions of poorer differentiation in which distinct pleomorphism, irregular secretory granules, increased numbers of ribosomesand a well developed rough endoplasmic reticulum were present. In 10% of the tumor cells GH could be demonstrated immunoenzymatically, but there was no TSH. The fourth adenoma was an undifferentiated acidophilic adenoma showing pleomorphic cells having slight acidophil and partly mucoid granulations. The ultrastructure showed convoluted nuclei, increased numbers of free ribosomes as well as abundant rough endoplasmic reticulum and secretory granules which were differentin size and number but distinctly of the TSH cell type. Immunoenzymatically, TSH was found in some cells, with GH in more cells. Endocrinologically, elevated levels of GH were measured in cases 2, 3 and 4 with LH being increased in case 1. Clinical and morphological correlations are discussed.

Adenoma↗
PubMed1982

Evaluation of surgically treated Nelson's syndrome.

In 17 primary transnasal operations on Nelson tumours long-term results are assessed measuring ACTH plasma levels and performing regular neuroradiological controls. In small intrasellar adenomas only one recurrent ACTH elevation near to pretreatment levels without symptoms from tumour growth was observed after 10 years. ACTH normalization was rarely achieved in large tumours, but only in one patient was a relapse visible in CT scan after three years. Thus selective tumour removal seems to be advisable at an early stage when sellar enlargement occurs. Interpretation of ACTH plasma levels has to include completeness of adrenalectomy, cystic tumour necrosis, and corticoid replacement which reduces ACTH levels. Elevation of ACTH plasma levels over 5,000 pg/ml has been regularly accompanied by extrasellar tumour extension. In large adenomas with definitely elevated ACTH levels, additional radiation therapy should be considered.

Adolescent↗
PubMed1982

In-vitro secretion of ACTH in Nelson's syndrome.

Cell suspensions of ACTH cell adenomas of 10 patients with Nelson's syndrome were investigated for in-vitro secretion of ACTH. Two incubation systems, one using incubation beakers and the other a superfusion system, were employed. The cells were tested for their reactivity to lysine-vasopressin (LVP), cortisol, and combinations of both. LVP regularly provoked a rapid significant increase of ACTH secretion. The effect of cortisol was heterogeneous. Paradoxical initial stimulatory effects of cortisol were observed. There was a suppressive effect in some patients, which correlates to low proliferative activity in histological evaluation. In both systems a low secretory activity coincided with high proliferative activity in vivo.

Adrenocorticotropic Hormone↗
PubMed1982

Objective and subjective evaluations of a TV-program versus small group instruction for the Iowa Drug Information Service.

The purpose of this study was to determine if the TV approach for instructing drug information systems is more efficient in terms of cost and learning effectiveness vs. traditional educational programming. The Iowa Drug Information Service system was selected as a typical representative for a study model. Second professional year pharmacy students (N = 66) were evaluated in a random selection, pre-test post-test, controlled experimental procedure. A 19 minute UTCHS in-house production served as the experimental variable. The control group received equivalent training (time and content) via lecture notes, and on-site practice coaching. Outcomes were assessed according to objective test score criteria and 10 subjective self-rating opinion scales. The data revealed that students subjected to the TV variable achieved significantly better post-exposure test scores (P = 0.002). A one-time cost of +500 was expended for complete TV production and three tapes, resulting in unlimited teaching capacity and recoverable within two years relative to instructor time expenditures for this system. Five of 10 opinion scales were significantly different in comparison, and students clearly preferred traditional teaching over our TV production. This investigation substantiates previous reports from medical disciplines wherein TV was an effective teaching approach but only mildly popular. The repetitive nature of didactic drug information systems training, superior TV outcomes, and cost-effectiveness warrants a mix of TV and limited personalized instruction as a policy approach.

Cost-Benefit Analysis↗
PubMed1981

ACTH secreting pituitary adenoma in an infant of 18 months. Immunohistochemical, electron-microscopic, and in-vitro studies.

An 18-month old infant with Cushing's disease due to an ACTH producing pituitary tumor is presented. The case showed typical clinical and morphological sings of hypercortisolism. The infant died of pulmonary thromboembolism after transsphenoidal partial adenomectomy. The adrenals were diffusely hyperplastic. The pituitary adenoma was classified as an undifferentiated mucoid cell adenoma with sparse granulation by light microscopy. Immunoenzymatic studies demonstrated ACTH not only in granulated adenoma cells. Ultrastructurally the cells were only differentiated as typical ACTH cells or so-called follicular cells in small areas. Most of them were undifferentiated, showing pleomorphism of the relatively sparse organelles. In-vitro experiments using suspensions of adenoma cells showed a distinct enhancement of ACTH secretion after arginine-vasopressin and a further decrease ultrastructurally in the number of secretory granules. No effect of ACTH levels and no alterations of the ultrastructure were observed after cortisol. The case is representative of typical hypothalamic-hypophyseal Cushing's disease with an undifferentiated pituitary adenoma secreting ACTH in part autonomously. This constellation of Cushing's syndrome is extremely rare at the age of one year. Our case is the second one reported in the literature.

Adenoma, Basophil↗
PubMed1980

Ultrastructural examination of the regeneration of the rat adenohypophysis after partial hypophysectomy.

Male Wistar rats were partially hypophysectomized and sacrificed at intervals of from 2 days to 1 year following the operation. The resected material was examined under the light microscope and the residual pituitary under the light and electron microscope. Neither regeneration nor an anatomical restoration of the adenohypophysis occurred even one year after partial hypophysectomy. An increased number of small chromophobe stem cells and juvenile chromophil cells were found in the residual pituitary. The amount of mitoses were not significantly increased. The ACTH, FSH and prolactin producing cells demonstrated electron microscopically distinct changes which were interpreted as signs of intensified activity. This can be seen as a "functional regeneration" to maintain vital pituitary function for the organism.

Animals↗
PubMed1980

Ultrastructural study concerning disintegration of fibrin foam used as filling material after partial hypophysectomy in rats.

After partial hypophysectomy in rats, fibrin foam was implanted in the wound cavity. The fate of the implant was followed over a period of time up to three months by light and electron microscopy. First of all granulocytes appeared, whose granules obviously participated in the fragmentation of the fibrin network. Two days after operation and then in rapidly increasing numbers histiocytes could be found which surrounded the fibrin fibres with pseudopodia and absorbed them. They were broken down intracellularly by the lysosomes. In the wound cavity the gradually increasing number of fibroblasts formed collagen that often lay close to the fibrin fibres. The disintegration of the Fibrospum corresponded largely to that of natural native fibrin even though some could be identified three months after operation. The isolated appearance of foreign giant cells argued in favour of a moderate tuberculin type allergic reaction by the rat.

Animals↗
PubMed1979

The ultrastructure of the pituitary gland under chronic stimulation of the ACTH-cells in human pathology and animal experiments.

Chronic stimulation of the ACTH-cells in rats was undertaken by adrenalectomy, chemical adrenostasis, by application of a CRF-analog and by non-specific means. The ultrastructural findings of the ACTH-cells were compared to those of the human pituitary gland in Cushing's disease. The pituitaries of 12 patients with the hypothalamic-hypophyseal form of Cushing's syndrome were studied by electron microscopy. A good correlation of the experimental observations to those in human pathology could be seen in the first steps of reaction. There was an enlargement of the ACTH-cells with well developed organelles and there was a simple hyperplasia. The following forms of reaction, nodular hyperplasia and adenomas, were only observed in the human pituitary glands. Chronic suppression by steroids leads to a diminution of the single ACTH-cell and their organelles and a reduction. The appearance of Crooke's cells is specific for the human pituitary and is not reproduced in animal experiments.

Adenoma↗
PubMed1978

Ultrastructure and morphometry of ACTH-producing cell in the rat anterior pituitary gland stimulated by lysin-vasopressin and prostaglandin E1.

The aim of this study was to investigate the qualitative and quantitative changes of ACTH-cells in the rat after application of a specific and a non-specific stimulus. A CRF-analog (lysin-vasopressin) and a prostaglandin (prostaglandin E1) were used. 40 rats were injected lysin-vasopressin or prostaglandin E1, respectively, for 4 weeks. The pituitary glands were investigated by means of light microscopy, electron microscopy and morphometry. Activation of the ACTH-cells could be observed after use of both substances, the effect of lysin-vasopressin being more intense than that of prostaglandin E1. Enlargement of the nucleus, the cytoplasm and the organelles involved in hormone-production and -transport were found and verified by morphometry. Additionally an increase in number of the cells could be demonstrated. Prostaglandin influenced not only ACTH-cells, but also other cells of the anterior pituitary.

Adrenocorticotropic Hormone↗