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Biomedical subjects

A Dekker

Publications and source records attributed to A Dekker.

At least 127 records · Page 7Linked to original sources
PubMed1979

Pulmonary silicatosis. A case diagnosed by needle-aspiration biopsy and energy-dispersive x-ray analysis.

The diagnosis of silicatosis was made by observing birefringent crystals in needle-aspiration biopsy specimens of bilateral basilar pulmonary masses in a clay worker, initially suspected of having metastatic neoplasm. Subsequently the crystals were examined by scanning electron microscopy and energy-dispersive x-ray analysis, which gave supportive evidence for their silicate composition. This experience indicates that needle-aspiration biopsy in conjunction with scanning electron microscopy and energy-dispersive x-ray analysis may be used in the diagnosis of benign pulmonary diseases, especially those of the inhalational fibrogenic variety.

Aged↗
PubMed1979

The pathologic assessment of primary hyperparathyroidism and its impact on therapy. A prospective evaluation of 50 cases with oil-red-O stain.

Normal and abnormal parathyroid glands removed surgically from 50 consecutive patients with primary hyperparathyroidism were studied by means of hematoxylin and eosin and oil-red-O stains. This was done to establish the incidence of the different pathological entities in our patient material, and to evaluate the role of the oil-red-O stain in the diagnostic histopathological process. The oil-red-O stain distinctly separates abnormally hyperfunctioning from normal or suppressed parathyroid tissue. Therefore, it is a valuable tool in the pathologic evaluation of patients with hyperparathyroidism. Chief cell adenomas were the most frequent lesions (88%), while diffuse hyperplasia was seen less commonly (10%) and carcinoma infrequently (2%). These findings justify a surgically conservative approach as the most desirable in managing patients with primary hyperparathyroidism.

Adenoma↗
PubMed1979

Computed tomographic localization for fine needle aspiration biopsy of orbital tumors.

Fine needle aspiration biopsy techniques have recently been applied to the evaluation of orbital masses. Ultrasound and CT examination have been useful in accurately localizing and characterizing such lesions prior to biopsy. Small retrobulbar tumors may be difficult to biopsy using blind needling, despite accurate localization. Preliminary studies on cadaver orbits confirmed that successful biopsy of the normal optic nerve could be accomplished using direct CT guidance. The technique was applied to 2 patients with monocular blindness due to small infiltrating optic nerve tumors and a histologic diagnosis was obtained in each case. This low morbidity procedure though applicable to only a small group of patients may spare them the morbidity of an orbitiotomy or craniotomy.

Adult↗
PubMed1979

In vitro and in vivo refractoriness to thyrotropin stimulation of iodine organification and thyroid hormone secretion.

Earlier studies indicated that initial exposure of thyroid slices to thyrotropin diminished responsiveness of the adenylate cyclase-cyclic AMP system, glucose oxidation, and (32)P(i) incorporation into phospholipids upon readdition of the hormone. The present studies demonstrate that slices from dog, beef, and human thyroid glands initially incubated with thyrotropin (TSH) were less responsive to subsequent addition of the hormone when organification of iodide was examined. Increasing the amount of TSH did not overcome the refractoriness induced by the initial exposure to the hormone. Furthermore, the stimulatory effects of dibutyryl cyclic AMP and prostagladin E(1) were abolished in slices previously incubated with TSH. Development of such refractoriness did not depend upon new protein synthesis and was not abolished by 1 mM prophylthiouracil in the first incubation. Addition of 0.1 muM thyroxine or triiodothyronine or 1.5 muM iodide during all three incubations did not modify the response to TSH, added for the first time in the third incubation. However, 1 mM iodide in the buffer during all three incubations inhibited the response to TSH during the third incubation. During the refractory period, effects of TSH on colloid droplet formation were also diminished. The in vivo effect of TSH on serum l- triiodothyronine in rats was significantly reduced when the rats had been injected with TSH 8 h earlier. These studies demonstrate that TSH-induced refractoriness also includes effects on organification of iodine and secretion of thyroid hormone. The results cannot be adequately explained by unresponsiveness of adenylate cyclase because effects of dibutyryl cyclic AMP and prostagladin E(1) were also inhibited by prior exposure to TSH.

Animals↗
PubMed1979

Effects of diamide on basal and thyrotropin-stimulated thyroid metabolism.

The effect of diamide on basal and TSH-stimulated thyroid metabolism was studied using bovine and dog thyroid slices. Diamide (10 mM) inhibited basal and TSH-stimulated net cAMP production, basal and cAMP-stimulated protein kinase activity, and stimulation by TSH of colloid droplet formation and organification of iodide and abolished basal and TSH-stimulated uptake of 32P into phospholipids. In thyroid slices incubated with 0.1 mM diamide, none of these activities, whether basal or TSH-stimulated, was affected. However, 0.1 mM diamide increased the net basal production of cAMP and potentiated the effect of TSH on this process. These results demonstrate that the previously reported inhibition of protein kinase by 2-20 mM diamide is not specific and that this compound cannot be used to determine which of the metabolic effects of TSH are dependent upon cAMP activation of protein kinase. While 0.1 mM diamide increased cAMP in thyroid slices, it did not reproduce any of the other effects of TSH.

Animals↗
PubMed1978

Ultrasound guided fine-needle aspiration biopsy of abdominal masses.

Twenty-six cases of ultrasonically guided percutaneous fine-needle aspiration biopsies of abdominal masses are reported. Included are masses in the pancreas, retroperitoneum, liver, kidney, and pelvis. Aspiration biopsies accurately diagnosed or excluded malignancy in 21 patients (81%). The procedure, performed under local anesthesia, is rapid, simple and almost painless. No complications occurred; specifically, there was no hemorrhage, peritonitis, or spread of tumor along the needle tract.

Abdominal Neoplasms↗
PubMed1978

Cytology of serous effusions. An investigation into the usefulness of cell blocks versus smears.

Approximately half of 351 body-cavity effusions from 263 patients were examined prospectively in paraffin-embedded cell blocks and in smears, while the other half were examined in smears alone. The number of suspect and positive fluids obtained with the combined cell block-and-smear technic was double that of specimens examined in smears only. No false-positive case was found. Tumors were subsequently demonstrated in 38% of the patients who had negative or atypical cytologic reports. Smears stained with the Papanicolaou technic generally have good definition of malignant cellular changes, wheras cell blocks are particularly useful when the cytologic abnormalities are misleading, such as in reactive mesothelial cells, or obscure, as in occasional well-differentiated adenocarcinomas. It is recommended that both cell blocks and smears be used in evaluating all fluids submitted to the cytology laboratory.

Aged↗
PubMed1978

Effects of thyroid-stimulating hormone on human thyroid carcinoma and adjacent normal tissue.

Effects of TSH on the adenylate cyclase-cAMP system and some parameters of intermediary metabolism were investigated in human thyroid carcinoma and adjacent normal thyroid tissue. Basal adenylate cyclase activity and cAMP concentrations were significantly higher in carcinomatous tissue. Basal [1-14C]glucose oxidation, 32Pi incorporation into phospholipids, and organification of iodide were similar in both tissues. Stimulation of cAMP by TSH was significantly greater in normal compared to carcinomatous tissue. In neither tissue was there a good correlation between TSH stimulation of adenylate cyclase activity and cAMP concentrations. The TSH stimulation of 32Pi incorporation into phospholipids by TSH was significantly greater in normal tissue. The mean effect of TSH on iodide organification and glucose oxidation was similar in normal and carcinomatous tissue. Although specific binding of TSH was demonstrated in both normal and carcinomatous tissue, it did not correlate very well with stimulation of adenylate cyclase activity. Hormones other than TSH also augmented adenylate cyclase activity in two of the carcinomas. In individual patients, the relative responsivity of carcinomatous tissue compared to normal was not always consistent when all of the metabolic parameters were considered.

Adenylyl Cyclases↗
PubMed1976

Pathologic findings from the national surgical adjuvant breast project (protocol no. 4). II. The significance of regional node histology other than sinus histiocytosis in invasive mammary cancer.

The morphologic appearances of regional lymph nodes in radical mastectomy specimens obtained from 303 women entered into a prospective study of invasive breast cancer were categorized into patterns that have been considered to reflect immunologic function. An attempt was made to correlate these with 31 other histological and 8 clinical features, including short-term treatment failure (3 months to 4 years, average 24 months). No significant relationship to the latter was encountered. However, a lymphocyte predominance pattern was significantly associated with a stellate tumor border, absent cell reaction within the dominant tumor, absent sinus histocytosis of lymph nodes, combination tumor types, and a patient age of 55 years or more. A similar relationship between age of patient and sinus histiocytosis was found with the germinal center predominance pattern. In addition, this histologic appearance was associated with circumscribed tumors, severe cell reaction, and the infiltrating ductal carcinoma NOS and medullary types. Nodes with an unstimulated appearance were also found to be related to an absent cell reaction but marked sinus histiocytosis and a patient age of 45-54 years. Possible reasons for the differences between these findings and those of others relating prognostic value to such assessment of nodal histology is discussed, as are the findings of studies relevant to the identity of immunologic function with the morphologic appearance of nodal structure. The findings from this study fail to indicate any value of such nodal assessments as prognostic discriminants for breast cancer. Although longer periods of observation might alter this conclusion, such an event is regarded as unlikely.

Adenocarcinoma, Mucinous↗
PubMed1976

Hashimoto's thyroiditis presenting as a solitary functioning thyroid nodule.

A case of hypothyroidism is described in a young woman who on thyroid scan had a discrete functioning "nodule" with homogeneous radioactive iodine uptake, and surrounded by atrophic non-functioning thyroid tissue. Antithyroglobulin antibodies were not demonstrable, but anti-microsomal antibodies were positive at a titer of 1:25,600. Histologically, the "nodule" represented Hashimoto's thyroiditis with more extensive destruction of the remaining gland. Although it is unusual, Hashimoto's disease should be considered in the differential diagnosis of functioning thyroid nodules, and both anti-thyroglobulin and anti-microsomal antibodies should be obtained in such circumstances.

Adult↗
PubMed1973

Demonstration of iodide transport defect but normal iodide organification in nonfunctioning nodules of human thyroid glands.

Benign and malignant nodules in human thyroid glands, which did not concentrate iodide in vivo, were also unable to accumulate iodide in vitro. The mean thyroid-to-medium ratio (T/M) in seven benign nodules was 0.8+/-0.2 compared with 7+/-2 in adjacent normal thyroid tissue. In four malignant thyroid nodules, the mean T/M was 0.5+/-0.1 compared with 11+/-4 in adjacent normal thyroid. Despite the inability of such nodules to concentrate iodide, iodide organification was present but was only one-half to one-third as active as in surrounding normal thyroid. Thyroid-stimulating hormone (TSH) increased iodide organification equally in both benign nodules and normal thyroid although it had no effect in three of the four malignant lesions. The reduction in organification is probably related to the absence of iodide transport, since incubation of normal thyroid slices with perchlorate caused similar diminution in iodide incorporation but no change in the response to TSH. Monoiodotyrosine (MIT) and di-iodotyrosine (DIT) accounted for most of the organic iodide in both the nodules and normal tissue. The MIT/DIT ratio was similar in normal and nodule tissue. The normal tissue contained much more inorganic iodide than the nodules, consistent with the absence of the iodide trap in the latter tissue. The thyroxine content of normal thyroid was 149+/-17 mug/g wet wt and 18+/-4 mug/g wet wt in the nodules. The transport defect in the nodules was not associated with any reduction in total, Na(+)-K(+)- or Mg(++)-activated ATPase activities or the concentration of ATP. Basal adenylate cyclase was higher in nodules than normal tissue. Although there was no difference between benign and malignant nodules, the response of adenylate cyclase to TSH was greater in the benign lesions. These studies demonstrate that nonfunctioning thyroid nodules, both benign and malignant, have a specific defect in iodide transport that accounts for their failure to accumulate radioactive iodide in vivo. In benign nodules, iodide organification was increased by TSH while no such effect was found in three of four malignant lesions, suggesting additional biochemical defects in thyroid carcinomas.

Adenoma↗