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Biomedical subjects

R A Wahl

Publications and source records attributed to R A Wahl.

At least 19 recordsLinked to original sources
PubMed1991

[Preventive operation of the thyroid gland].

Since the transformation of adenoma into carcinoma has not been proved, surgery of cold nodules cannot be classified as "prophylactic". Early treatment of differentiated carcinomas can, however, prevent transformation into anaplastic carcinoma. Prophylactic lymphnode dissection is of proven value only in C-cell carcinoma; C-cell hyperplasia in the hereditary type of this tumor is the only clearly prophylactic indication to total thyroidectomy. Hyperthyroidism in functional thyroid autonomy can be prevented in a euthyroid stage. The aim of prophylaxis against recurrent goiter and hyperthyroidism influences the operative strategy in both, immunogenous and non-immunogenous hyperthyroidism.

Diagnosis, Differential↗
PubMed1990

[What is the place of "selective thyroid gland resection" in surgery of benign nodular struma].

Remnants after "classic" Subtotal Thyroidectomy are of constant size in constant position. "Selective" thyroidectomy intends to remove all nodules, but to save normal tissue--irrespective of their localization. From July 1985 to Dec. 1989 in 48.5% of 1124 thyroid lobes sel. surgery was performed, in 27.8% subtotal, in 23.8% total lobectomy. Primary postop. recurrent lar. palsy occurred in 1.3% after sel., 1.0% after subt. and 2.7% after total lobectomy. 90% of primary r.l.n.p.'s were transient--after sel. lobectomy only one persistend (0.2%). Hypocalcemia: 0.7% after sel., 1.4% after subt. thyroidectomy. Besides better quality and quantity of remnants selective thyroidectomy is supported by low rate of complications.

Goiter, Nodular↗
PubMed1988

[Hormone active versus hormone inactive parathyroid gland cancer].

Problems regarding diagnosis and treatment of hormonally active and hormonally inactive parathyroid carcinomas arise from opposite sides, as is shown in two resp. cases. In functionally active tumors parathyroid origin is clear--but how to prove malignancy in early tumor stages? In inactive tumors malignancy is sound--but how to prove their parathyroid origin? Meticulous histologic examination (semithin-Layer) and cytophotometric DNA-measurement may be helpful diagnostic tools for active tumors, immunohistochemistry and analysis of parathormone fragments in plasma and tumor-cell-culture for inactive tumors. Nevertheless the surgeon's decision for radical surgery sometimes will have to be put on the intraoperative macroscopic situs--in order to provide curative treatment.

Adult↗
PubMed1988

[Reintervention in C-cell carcinoma].

Cervical re-exploration in persistent medullary thyroid cancer usually fails to normalize serum calcitonin levels, which is the most sensitive criterion of tumour-free status (2 out of 21 patients in our re-exploration series). Positive lymph nodes - even at an early tumour stage - seem much more important (postoperative normal serum calcitonin: 86% in the occult tumour group, 71% in patients with palpable primary tumour and negative lymph nodes, as opposed to only 18% with a palpable cervical mass and positive lymph nodes). However, local re-exploration in case of persistent medullary thyroid cancer seems to offer a possible curative chance for the control of recurrence, especially after inadequate primary surgery. In cases without visible distant metastases a marked reduction in serum calcitonin level may be expected (21% of the preoperative level for stages N1 and N2 and 16% for stage N3 on average). In patients with elevated calcitonin levels after stimulation as sole indicator of persistent tumour the indication for reoperation should be handled cautiously. Thus, in 3 out of 5 patients with occult medullary thyroid cancer diagnosed only on the basis of venous sampling who were subjected to multiple cervical re-explorations, distant metastases were subsequently found during follow-up.

Calcitonin↗
PubMed1987

[Surgery of metastases of differentiated thyroid cancers].

84 (19.5%) of 431 patients with differentiated thyroid cancer developed distant metastases in bone and parenchymal organs. 78% of primary bone metastases and only 21% of primary lung metastases were treated operatively. High survival rates of 33-60% at 5 years supported the necessity of surgical interventions primarily in bone metastases to prevent early morbidity due to pathological fractures. Even in case of questionable increase in survival rate surgery of metastases from differentiated thyroid carcinomas doubtlessly improves the quality of life in these patients.

Adenocarcinoma↗
PubMed1987

Nerve growth factor (NGF) sensitizes human medullary thyroid carcinoma (hMTC) cells for cytostatic therapy in vitro.

Medullary thyroid carcinoma (hMTC) cells were established from nine patients with MTC disease to initiate a new approach of adjuvant medical therapy in these patients. We measured calcitonin (CT) secretion, DNA synthesis, and cell proliferation in vitro and their response to various substances. Nerve growth factor (NGF) (0.01 to 10 micrograms/ml), glucagon (0.01 to 100 micrograms/ml), and isoproterenol (4 to 500 micrograms/ml) stimulated CT secretion and DNA synthesis in hMTC cells. Other substances, calcium (1.0 to 15 mmol), pentagastrin (1.0 to 50 mumol), dibutyryl-cyclic-adenosine-monophosphate (1.0 to 100 mumol), and phorbol ester TPA (1.0 to 100 nmol), stimulated CT secretion but not DNA synthesis. In addition, NGF enhanced cell proliferation of hMTC cells 2- to 3- fold and caused an increased sensitivity of these cells for chemotherapy in vitro. Thus 0.5 microgram/ml doxorubicin (half-maximal effective dose) induced a cell death rate of up to 32.8%, which was enhanced by preincubation with NGF to 68.1% (1.0 microgram/ml, NGF) and to 100% (10.0 micrograms/ml, NGF), respectively. Pulsative stimulation of APUD cell carcinomas with NGF may therefore improve the response rate of these tumors to chemotherapy, which would be of significant clinical importance for patients with residual postoperative MTC tissue.

Antineoplastic Agents↗
PubMed1985

Thyroid function after surgery for autonomous and non-autonomous nodular endemic goitre--effect of iodide-substitution.

The aim of this study was to evaluate the influence of postoperative iodide-substitution on the function of thyroid remnants of different quality and quantity in order to define the appropriate prophylaxis (iodide or thyroid hormone) to prevent recurrent goitre. In a prospective, randomized clinical trial, the following patients were examined: group I: simple, non-autonomous nodular goitre, bilateral thyroidectomy (n = 40); group II: simple, non-autonomous nodular goitre, "selective" (unilateral) thyroidectomy (n = 40); group III: autonomous nodular goitre, bilateral thyroidectomy (n = 40); group IV: autonomous nodular goitre, "selective" (unilateral) thyroidectomy (n = 35). The following parameters were measured 6 and 12 weeks postoperatively. Serum-total-T4, -T3, -TSH, TRH-test, 99mTc-Thyroid-Uptake (TcTU). Six weeks postoperatively the 4 groups were separately randomized into controls and treatment groups, who received 200 micrograms iodide/day orally. Six weeks postoperatively, patients in group I had lower T4 levels and both basal and stimulated TSH were higher than in the other groups, however no significant differences were observed in T3, T4/T3 ratio and TcTU. Twelve weeks postoperatively patients from groups I, II and III, who had been treated with iodide, had lower T3 and TcTU values but higher T4 and T4/T3 than the appropriate controls. Basal and stimulated TSH showed no differences between controls and iodide-treated patients in these groups. In group IV, T4 and T3 showed a tendency to elevation (n.s.), and basal and stimulated TSH as well as TcTU were lower in patients with iodide.(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical Trials as Topic↗
PubMed1985

[Radicality principles in operations on malignant thyroid tumors].

Different concepts are required by different tumors: anaplastic carcinomas rarely are accessible to curative surgery, but tumor reduction gives sense in combined concepts. In follicular carcinomas general ("near"-) total thyroidectomy + radioiodine + hormonal suppressive therapy is recommended, with respect to the high incidence of distant metastases even in low 1 degree Tu-stages. Papillary carcinomas allow a stage related procedure with exceptions from total thyroidectomy: no reintervention for "occult" carcinomas and-in patients under 40 years of age-hemithyroidectomy for intrathyroid tumors without regional metastases. In C-Cell-carcinomas total thyroidectomy has to be accompanied by lymph-node dissections of various extent, depending on familiary or sporadic type and tumor-stage.

Adenocarcinoma↗
PubMed1985

Low T3 syndrome in patients following major surgery.

Time sequence and specificity of thyroid hormones and biochemical parameters were investigated in patients following major surgery. Serum concentration of triiodothyronine decreases significantly following operation, with a biphasic regression. There is a reciprocal change in serum reverse triiodothyronine levels, but serum thyroxine levels show no significant change after operation. The significant decrease in serum concentration of alpha-2-macroglobulin and antithrombin III during and after surgery is the result of consumption of these inhibitors because the reciprocal change in serum concentration of elastase-like protease has been recognized. According to the change of curvilinear regression of serum triiodothyronine levels, 14 patients were grouped into 3. The patients for whom the curvilinear regression resembled a polynomial of degree 3 and 2 had a good prognosis, but the remaining 4 with no significant curvilinear regression had major complications and 2 died. It is meaningful that the postoperative change of triiodothyronine levels relates to the clinical outcome, to some degree.

Adolescent↗
PubMed1984

Absence of high-affinity binding sites for beta-adrenergic blockers and lack of adenyl cyclase stimulation to beta-adrenergic stimulators in most normal and adenomatous human thyroid tissues.

To determine whether the beta-blocking drug propranolol had any physiologic effect on normal (n = 14) and adenomatous (n = 15) human thyroid tissues, experiments were performed to study the binding of the beta-blockers 125I-iodocyanopindolol (125I-ICYP) and 125I-iodohydroxybenzylpindolol (125I-IHYP) and the stimulation of adenyl cyclase (AC) by isoproterenol. 125I-ICYP and 125I-IHYP failed to show high-affinity binding in 27 of 29 specimens, whereas two (one normal and one adenomatous) thyroid tissues demonstrated high-affinity binding (Kd 5.5 +/- 1 X 10(-9) M) for 125I-ICYP. Thyroid-stimulating hormone (0.3 IU/ml), guanosine triphosphate (10(-4) M), and Gpp (NH)p(10(-4) M) stimulated AC in all thyroid tissues, although in two tissues (normal) Gpp (NH)p failed to cause a significant increase. Isoproterenol (10(-4) M), in contrast, had no effect on basal AC activity or on guanosine triphosphate, and Gpp (NH) p stimulated AC activity in 26 of the 29 thyroid tissues. In one of the two tissues that increased AC in response to isoproterenol, the beta-blocking drugs propranolol hydrochloride, bunitrolol hydrochloride, and tolilprolol hydrochloride decreased AC stimulation to isoproterenol at concentrations of 10(-6) M (p less than 0.05). Higher concentrations of propranolol (10(-4) - 10(-2) M) decreased AC stimulation to thyroid-stimulating hormone (p less than 0.01), not only in this responsive tissue but also in tissues that failed to demonstrate high-affinity binding for 125I-ICYP and AC stimulation to isoproterenol (p less than 0.01). Thus most normal and adenomatous human thyroid tissues lack beta-receptors and a functioning beta-receptor AC system. High concentrations of propranolol in vitro decreased AC response by thyroid-stimulating hormone, but this is probably a nonreceptor-mediated effect.

Adenoma↗
PubMed1981

[Early recognition of C-cell carcinoma by family screening (author's transl)].

All available family members of five patients with C-cell carcinoma (medullary carcinoma of the thyroid) were tested for their basal serum-calcitonin level and after pentagastrin stimulation. In two females, aged 12 and 25 years, from two different families, serum-calcitonin was elevated, but only after repeated tests or after pentagastrin stimulation, to definitely abnormal levels. Neither had palpable thyroid nodules, lymph-adenopathy or diarrhoea. The thyroid scan was normal and there were no storage defects. But because of the family history and the elevated serum-calcitonin levels total thyroidectomy was performed in both. The specimens revealed multicentric, bilateral C-cell carcinomas. The serum-calcitonin concentration became completely normal postoperatively, so that one may justifiably speak of a curative effect of the thyroidectomy in these two instances of early diagnosis.

Adult↗