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Biomedical subjects

B Hamberger

Publications and source records attributed to B Hamberger.

At least 109 records · Page 6Linked to original sources
PubMed1982

Fine-needle aspiration biopsy of thyroid nodules. Impact on thyroid practice and cost of care.

We studied the impact of fine-needle aspiration biopsy on the management of patients with solitary thyroid nodules. Sixty-four patients were examined before the introduction of fine-needle aspiration biopsy, and 147 patients were examined after its introduction. The percentage of patients who underwent thyroid operation decreased from 67 percent to 43 percent, while the yield of carcinoma increased from 14 percent to 29 percent. Cost of medical care per patient declined by 25 percent. The results suggest that fine-needle aspiration biopsy provides valuable information to assist in the selection for surgery of patients with solitary nodules. Fine-needle aspiration appears to be safe, reliable, and cost-effective. The merits of the technique commend it for routine use in the evaluation of thyroid nodules.

Biopsy, Needle↗
PubMed1981

Dopamine infusion in man. Plasma catecholamine levels and pharmacokinetics.

Dopamine is widely used in the treatment of hypotensive conditions and/or impending renal failure, but the plasma levels of dopamine and other catecholamines in association with dopamine infusion are not known. Plasma catecholamines and dopamine pharmacokinetics during and after dopamine infusion were therefore studied in man. Two and 5 micrograms x kg-1 x min-1 of dopamine were infused for 30 min in two groups of five patients. Dose-dependent mean steady state levels with fairly large interindividual variations were reached within 5 min. Elimination of dopamine from plasma after termination of infusion had a biphasic course with t 1/2 alpha around 1 min and t 1/2 beta about 9 min in both groups. Noradrenaline plasma levels and blood pressure increased significantly in the 5 micrograms group. It is suggested that the vasoconstriction with deleterious effects on tissue perfusion, seen in conjunction with high-dose dopamine infusion, may be due to increased noradrenaline levels.

Adult↗
PubMed1981

The role of catecholamines in the control of gastrin and acid secretion during insulin hypoglycaemia in man.

5 adrenalectomized subjects and 8 healthy volunteers underwent an insulin test during which acid secretion and plasma adrenaline, noradrenaline, dopamine and gastrin concentrations were measured. Plasma glucose concentration fell by greater than 50% in all subjects. The mean plasma adrenaline concentration increased markedly (greater than 1,000%) in the normal group but was unchanged in the adrenalectomized group. In all subjects, plasma noradrenaline concentration increased moderately, whereas plasma dopamine levels remained unchanged. Clear-cut increments in plasma gastrin concentration were seen only on 3 participants, each of whom responded to insulin hypoglycaemia with an extremely high adrenaline release. Basal and peak acid output were similar in adrenalectomized and normal subjects. The results suggest that circulating catecholamines contribute to the control of gastrin and acid secretion in man only during circumstances with high plasma catecholamine levels, e.g. severe stress.

Adult↗
PubMed1981

The relation between catecholamines, glucagon and pancreatic polypeptide during hypoglycaemia in man.

The effects of insulin hypoglycaemia (0.15 IU/kg) on plasma adrenaline, noradrenaline, dopamine, glucagon and pancreatic polypeptide (PP) concentrations were investigated in 6 adrenalectomized subjects and 6 healthy controls. Both the rise in mean plasma insulin and the fall in mean blood glucose concentration were closely similar in the two groups. Mean plasma adrenaline concentration rose by about 3 nmol/l in the normal subjects, but remained unchanged in adrenalectomized subjects. Mean plasma noradrenaline concentration increased by about 2 nmol/l in both groups. Despite the large difference in adrenaline concentrations during hypoglycaemia, there was no significant difference between the responses of the endocrine pancreas of the normal and adrenalectomized subjects. Thus, mean plasma glucagon concentration rose by about 30 pmol/l and mean plasma PP concentration by about 150 pmol/l in each group. We conclude that the release of glucagon and PP during hypoglycaemia does not depend upon changes in plasma adrenaline concentration in man.

Adrenalectomy↗
PubMed1981

Pheochromocytoma of the bladder. A case report.

A 39-year-old male patient with attacks of headache and tachycardia immediately after micturition is described. Systolic blood pressure of 250 mmHg was measured after voiding. Plasma noradrenaline was increased 10 to 20 times above the normal value during the attacks. Cystoscopy, arteriography, catheterization of the caval vein with sampling for plasma catecholamines and computerized tomography all supported the diagnosis of a bladder tumour. A beneficial effect of alpha-receptor blockade preoperatively was demonstrated. The tumour was operatively removed from the bladder. The postoperative course was uneventful.

Adult↗
PubMed1981

Plasma catecholamine levels in the diagnosis and management of pheochromocytoma.

Plasma catecholamine levels have been determined before, during and after operation in seven consecutive patients operated upon for pheochromocytoma. The method used permits the simultaneous determination of norepinephrine, epinephrine and dopamine. All patients had increased levels of one or several catecholamines while hypertensive. Two of seven patients had normal levels of catecholamines while they were normotensive. Spontaneous or provoked attacks strongly increased plasma catecholamine levels. The present method may prove to be of value as a simple method to ascertain or exclude pheochromocytoma. During operation plasma norepinephrine and epinephrine levels increased up to 600fold when the tumor was manipulated. The unpredictable rapid and large variations in levels of catecholamines found during operation suggest preoperative alpha-adrenergic receptor blockade and monitoring of central circulation.

Adolescent↗
PubMed1980

Cellular localization of peptides in neural structures.

By means of the immunohistochemical technique of Coons and collaborators, numerous peptide-containing neurons have been observed in the brain, spinal cord and periphery. These neurons may contain peptides such as substance P, vasoactive intestinal polypeptide (VIP), enkephalin or somatostatin. Some systems are very extensive. For example, immunoreactive substance P has been observed in more than 30 cell groups in the central nervous system, in primary sensory neurons, in sensory neurons in the vagus nerve and in taste buds, and in intestinal neurons. Thus, one and the same peptide can be utilized at many different levels in the nervous system. Several examples are now known where a regulatory peptide occurs together with a classical transmitter, such as a catecholamine, in the same neuron, which suggests the possibility that a neuron can release more than one transmitter substance. Of particular interest is the occurrence of VIP in presumed cholinergic neurons innervating exocrine glands in the cat, and the coexistence of a cholecystokinin (CCK)-like peptide in dopamine neurons projecting mainly to limbic areas. In the former system VIP seems to be responsible mainly for vasodilation, whereas acetylcholine mainly causes secretion. Furthermore, combined infusion of both substances in very low doses results in a marked potentiation of the secretory and vasodilatory responses. Thus, we have an example where two putative transmitters, released from the same nerve endings, seem to cooperate to activate a physiological response (secretion). With regard to the central CCK/dopamine neurons the type of interaction between the two coexisting transmitter candidates is at present unclear. It is suggested that elucidation of different types of coexistence phenomena may advance our understanding of chemical transmission at synapses under normal and pathological conditions, and may lead to new approaches to the treatment of some nervous disorders.

Adrenocorticotropic Hormone↗
PubMed1980

Cyclic AMP and metabolic substrates following hemorrhage in awake and anesthetized rats.

The levels of several metabolites in plasma were studied during a period of 4 h in awake and barbiturate anesthetized rats after a blood volume loss of approximately 3% of b.w. Blood pressure was 70 mmHg (9.3 kPa) in the awake and 35 mmHg (4.7 kPa) in the anesthetized rats. Resting levels of plasma glucose, blood lactate and pyruvate and plasma cyclic AMP were higher in the awake rats than in the anesthetized rats. Bleeding caused an increase of plasma glucose in both groups. There was a more rapid increase in blood lactate and pyruvate as well as in plasma cyclic AMP levels in the awake rats than in the anesthetized rats. By contrast, plasma glycerol levels were unaltered by bleeding, and plasma FFA levels were decreased in both groups. At the end of the 4-h bleeding period plasma glucose was higher and blood lactate levels were lower in the awake rats. The initial changes in plasma metabolite levels appeared to be directly related to changes in plasma catecholamine levels. There were no differences in the relationship between the adrenaline level and cyclic AMP or glucose increase, suggesting that anesthesia did not alter beta-adrenoceptor sensitivity, but only catecholamine concentrations. The results also indicate that awake rats tolerate long-lasting blood volume loss better than anesthetized rats, because the sympatho-adrenal activation is more short-lasting.

Anesthesia, General↗
PubMed1979

Enkephalin- and somatostatin-like immunoreactivities in human adrenal medulla and pheochromocytoma.

By using the Coons indirect immunofluorescence technique, enkephalin-like immunoreactivity with a granular localization was observed in human adrenal medullary gland cells and pheochromocytomas. In two of the tumors and in a few adrenal gland cells, a somatostatin-like peptide could also be identified. Catecholamine cell types were visualized on adjacent sections with antisera to the synthesizing enzymes dopamine-beta-hydroxylase [DBH; dopamine beta-monooxygenase; 3,4-dihydroxyphenylethylamine, ascorbate: oxygen oxidoreductase (beta-hydroxylating), EC 1.14.17.1] and phenylethanolamine-N-methyltransferase (PNMT; noradrenalin N-methyltransferase; S-adenosyl-L-methionine:phenylethanolamine N-methyltransferase, EC 2.1.1.28). In the normal adrenal medulla more DBH- than PNMT-immunoreactive gland cells were observed. In the adrenal pheochromocytoma both DBH- and PNMT-positive cells were seen, whereas the two extra-adrenal tumors contained only DBH. These findings correlated well with plasma catecholamine measurements. Finally, enkephalin immunoreactive fibers and somatostatin immunoreactive cells were observed in a sympathetic ganglion extirpated together with one of the tumors.

Adrenal Gland Neoplasms↗
PubMed1979

Plasma catecholamines, cyclic AMP and metabolic substrates in hemorrhagic shock of the rat. The effect of adrenal demedullation and 6-OH-dopamine treatment.

Plasma catecholamines, cyclic AMP and metabolic substrates in hemorrhagic shock of rats was studied in 4 groups of animals: 1) Control rats, 2) rats with adrenal demedullation, 3) rats with 6-OH-dopamine induced chemical sympathectomy, and 4) rats with combined demedullation and sympathectomy. The rats were bled to a systemic blood pressure of 35 mmHg. The basal plasma level of noradrenaline (NA), adrenaline (A) and dopamine (DA) in control animals was each about 1 nmol/1. After hemorrhage for 1 h the A levels had reached 50 nmol/l and there was little further rise after 4 h. The rise was eliminated by demedullation but unaffected by sympathectomy. NA levels rose continuously in the control and in the sympathectomized rats. At 1 h the level was about 4 nmol/l and at 4 h about 20 nmol/l. The demedullated rats showed a 3-fold increase in circulating NA, while little or no change was seen in the combined demedullated and sympathectomized rats. DA levels did not change in any of the groups during the first hour, but were markedly elevated after 4 h of hypotension. Cyclic AMP and glucose levels in plasma showed a rapid increase 1 h after hemorrhage and thereafter returned to or below basal values. Demedullation largely prevented the increase, while sympathectomy had no effect. The increase in lactate and pyruvate levels were diminished but not eliminated by either sympathectomy or demedullation. Glycerol levels were unchanged and FFA decreased in all groups of rats. The results show that the adrenal medulla is the dominating source of plasma catecholamines in hemorrhagic shock in rats. The initial increase in plasma glucose and cyclic AMP appear to be largely mediated by adrenal A. The subsequent fall in these parameters and derangement of circulatory homeostasis are not, in the present shock model, primarily due to a failure of catecholamine secretion, but rather to a decreased responsiveness of peripheral tissues to catecholamine stimulation.

Adrenal Medulla↗
PubMed1979

Catecholamines and hemorrhagic shock in awake and anesthetized rats.

Catecholamines in plasma and tissue were determined during hemorrhagic shock in the rat. Two groups of rats were compared. 1. Awake rats bled to 70 mm Hg for 4 hours. 2. Anesthetized rats (pentobarbital sodium 60 mg/kg) bled to 35 mm Hg for 4 hours. The mortality rate was similar in both groups. The bled volume was also similar. The awake rats responded with tachycardia upon bleeding while the anesthetized rats responded with bradycardia. The basal plasma levels of noradrenaline (NA), adrenaline (A) and dopamine (DA) in the awake rats were 2.87, 4.09, and 0.51 nmol/l respectively and in the anesthetized rats 0.97, 0.54, and 0.56 nmol/l respectively. At the onset of bleeding there was a more rapid increase of plasma A and NA in the awake rats than in the anesthetized rats. In the awake rats plasma A reached its peak value (70 nmol/l) at 1 hour and then decreased, while NA showed a slow continuous rise to 17 nmol/l at 4 hours. In the anesthetized rats plasma A remained at a high level (about 60 nmol/l) between 1 and 4 hours, while there was a continuous rise of NA to 17 nmol/l at 4 hours. In these rats a very high DA level (17 nmol/l) was also found at 4 hours. The tissue content of NA was not significantly decreased in the heart while a significant decrease was seen in the skeletal muscle after bleeding for 4 hours. In the heart there was a substantial increase of A after bleeding. The A content of the adrenals decreased to about 25% of the initial value in the awake animals. The results show that barbiturate anesthesia considerably depresses the initial sympatho-adrenal response to bleeding.

Adrenal Glands↗
PubMed1977

Cyclic AMP and metabolic substrates in hemorrhagic shock of the rat.

Hemorrhagic shock was induced in rats by bleeding to 35 mmHg for a period of 4 h. Plasma glucose increased rapidly following the onset of bleeding and reached twice the control value after 30 min. After 2 h hypotension the liver content of glycogen was depleted and subsequently the rats became hypoglycemic. The rise in plasma glucose was accompanied by a rise in plasma cyclic AMP, which was 10-fold after 1 h, but returned towards control values at the end of the hypotensive period. There were no corresponding changes in the cyclic AMP contents of liver, heart or adipose tissue. Blood lactate was increased 10-fold and the lactate/pyruvate ratio was more than doubled, suggesting an increased anaerobic metabolism. Plasma FFA levels fell significantly, while plasma glycerol was unchanged during the hypotensive period. In this hemorrhagic shock model there is an initial phase of glucose mobilization from the liver, which is accompanied by elevated plasma cyclic AMP. This phase is followed by a period of depressed levels of glucose as well as FFA and thus a lack of metabolizable substrates in plasma.

Adipose Tissue↗
PubMed1977

Noradrenergic mechanisms in hemorrhagic shock of the rat.

The effects of hemorrhagic shock on the noradrenergic nerves of the rat were studied. Fluorescence microscopy of these nerves combined with biochemical determination of noradrenaline revealed a highly selective activation of certain adrenergic nerves, especially the nerves of the arterioli. Under the present experimental conditions transmitter mechanisms such as uptake and release of noradrenaline were not severely impaired by shock.

Animals↗