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Biomedical subjects

B Hamberger

Publications and source records attributed to B Hamberger.

At least 55 records · Page 3Linked to original sources
PubMed1988

High- and low-dose fentanyl anaesthesia: hormonal and metabolic responses during cholecystectomy.

We have compared two groups of patients given low- or high-dose fentanyl anaesthesia. Arterial blood samples were collected for measurement of glucose, free fatty acids (FFA), glycerol, beta-hydroxy-butyrate, insulin, c-peptide, glucagon, human growth hormone (HGH), cortisol and adrenaline concentrations. After induction of anaesthesia, blood concentrations of most of these substances decreased. After the start of surgery the concentrations of cortisol, glucose, HGH, FFA and beta-hydroxy-butyrate increased significantly in the group anaesthetized with the lower dose of fentanyl. In the group that received high-dose fentanyl anaesthesia the plasma concentrations of almost all the hormones and substances measured remained relatively low. The differences between the two groups during surgery were significant for adrenaline (P less than 0.001) and cortisol (P less than 0.001). High-dose fentanyl appears to block the trauma-induced stress response seen in patients anaesthetized with low dose fentanyl.

Adult↗
PubMed1988

Paravertebral block during cholecystectomy: effects on circulatory and hormonal responses.

Surgical trauma induces a hormonal metabolic response which is partly responsible for postoperative catabolism. In this study 12 patients underwent cholecystectomy during isoflurane anaesthesia, six with a paravertebral block (PVB) in addition. Plasma concentrations of glucose, cortisol and adrenaline, and heart rate and arterial pressure were compared between the two groups. The patients with PVB showed a significantly diminished response to noxious stimuli.

Adult↗
PubMed1988

Effects of ephedrine on renal function in patients after major vascular surgery.

The haemodynamic and renal effects of ephedrine were studied in 11 mechanically ventilated patients on the first day after major vascular surgery. Ephedrine, a sympathomimetic agent with alpha-1, beta-1, and beta-2 agonistic activity, was infused into 11 patients to achieve a 20% rise in systolic blood pressure. The doses used were 2-6 micrograms/kg/min, and in six of these 11 patients the dose was then doubled, 4-12 micrograms/kg/min for another renal function test. Blood pressure, heart rate, and cardiac output increased at both dose-ranges. Systolic pulmonary arterial pressure increased by 10% at the first dose-range. Systemic vascular resistance was unchanged and plasma catecholamine levels were unaltered in the present study. Plasma renin activity diminished by 18% and 6%, respectively. Clearance of para-aminohippuric acid increased by 20% and 6%, at the two dose-ranges, while clearance of inulin and urine flow rate increased by 24% and 29%, respectively, at the first dose-range, without further increase during the second dose-range. Fractional chloride excretion, and fractional osmolar clearance were unaltered. Fractional Na+ clearance rose by 30% and 36%, respectively. Fractional free water clearance diminished by 8% at the second dose-range. When comparing the two dose-ranges, HR, systolic and mean BP rose by 8%, 13% and 11%, respectively. Fractional K+ excretion diminished by 30%. We conclude that ephedrine given as a continuous infusion seems to have beneficial effects on renal function in patients after elective major vascular surgery.

Aged↗
PubMed1987

Catecholamine content and adenylate cyclase activity in corpora lutea of different ages of the PMSG-treated immature rat.

The catecholamine content and adenylate cyclase response were studied in a well-characterized corpus luteum model, where ovulation was induced by treatment of prepubertal Sprague-Dawley rats with pregnant mare's serum gonadotropin. The luteal content of noradrenaline, determined with HPLC, was constant during the first 7 days of pseudopregnancy, followed by a 3-fold increase in older corpora lutea. No detectable amounts of dopamine were found, while trace amounts of adrenaline were found in a few cases. The increase in noradrenaline content was not associated with a changed sensitivity of luteal adenylate cyclase to catecholamines. The response to adrenaline was maximal in 3-day-old corpora lutea, whereafter a decrease was seen. The significance of the increased endogenous levels of noradrenaline at the end of pseudopregnancy is at present unknown. However, the fact that the increase in noradrenaline occurs a few days before spontaneous luteolysis is of special interest, since it has been suggested that an adrenergic innervation is a prerequisite for the antigonadotropic effect of prostaglandin F2 alpha in the human corpus luteum.

Adenylyl Cyclases↗
PubMed1987

High- and low-dose fentanyl anaesthesia: circulatory and plasma catecholamine responses during cholecystectomy.

The cardiovascular and neuroendocrine effects of a high-dose fentanyl anaesthesia (100 micrograms/kg body weight) were compared with those of a balanced type of fentanyl anaesthesia (5 micrograms kg-1) during upper abdominal surgery. High-dose fentanyl anaesthesia prevented the increase in catecholamine concentrations and attenuated the circulatory response to surgical stress seen in the group anaesthetized with the balanced technique of anaesthesia.

Adult↗
PubMed1987

Effects of metoprolol on the counter-regulation and recognition of prolonged hypoglycemia in insulin-dependent diabetics.

The effect of metoprolol on the counter-regulation of prolonged hypoglycemia was studied in eight insulin-dependent diabetics. Insulin was given as an i.v. infusion of 2.4 U/h over 180 min alone, or together with metoprolol (3.0 mg i.v. bolus followed by an i.v. infusion of 4.8 mg/h) in random order. Blood glucose, counter-regulatory hormones, hypoglycemic symptoms and the cardiovascular responses were assayed over 240 min. Metoprolol did not significantly modify the blood glucose levels. The plasma levels of free insulin, however, were elevated by approximately 20% (p less than 0.01) by metoprolol during hypoglycemia and the plasma concentrations of epinephrine, norepinephrine, growth hormone and cortisol were enhanced by the drug. Sweating was increased by metoprolol, while other symptoms were unaltered. We conclude that metoprolol administered acutely does not aggravate prolonged hypoglycemia in diabetics with blunted response of glucagon. Moreover, exaggerated responses of counter-regulatory hormones, provoked by metoprolol, may compensate for the inhibitory effect of this drug on insulin clearance.

Adult↗
PubMed1987

Release of neuropeptide Y upon haemorrhagic hypovolaemia in relation to vasoconstrictor effects in the pig.

Neuropeptide Y is co-stored with noradrenaline in peripheral sympathetic nerves, but is not present in the adrenal chromaffin cells in the pig. Plasma levels of neuropeptide Y-like immunoreactivity and catecholamines were studied upon haemorrhagic shock in the anaesthetized pig. The animals were bled in two successive steps (30 and 10 ml kg-1), resulting in a reduction of the mean arterial blood pressure by 44% and 53%, respectively. Plasma levels of noradrenaline increased abruptly after the first bleeding from 1.21 +/- 0.27 to 26.5 +/- 6.3 nmol l-1. Plasma neuropeptide Y showed a progressive increase from 62 +/- 8 pmol l-1 in the basal state to 365 +/- 98 pmol l-1 at 60 min after the first bleeding. After the second bleeding plasma neuropeptide Y and noradrenaline showed a largely parallel increase and finally reached levels of 2524 +/- 580 pmol l-1 and 316 +/- 117 nmol l-1, respectively. A veno-arterial gradient of neuropeptide Y and noradrenaline indicating local release was present over the spleen after both bleeding steps. The overflow of neuropeptide Y was delayed about 15 min compared to noradrenaline after the initial bleeding. Depletion of the neuropeptide Y content after shock in the heart and skeletal muscle supported local release also from these organs. Infusions of neuropeptide Y to obtain similar plasma concentrations as during shock (nM range) caused reduction in blood flow as determined by the radionuclide-labelled microsphere technique in several organs including spleen and skeletal muscle (threshold response at 319 +/- 22 pmol l-1) but not in heart and brain. In conclusion, both neuropeptide Y and noradrenaline were markedly elevated in plasma upon haemorrhagic shock, suggesting release from sympathetic nerve terminals. Neuropeptide Y could therefore have a role as a sympathetic neurotransmitter, and during severe stress, circulating plasma levels are in the range where vasoconstriction is evoked by exogenous NPY.

Animals↗
PubMed1987

Catecholamine release after physical exercise. A new provocative test for early diagnosis of pheochromocytoma in multiple endocrine neoplasia type 2.

A simple and practical provocative test is needed for early asymptomatic pheochromocytoma, which is a major risk for patients with multiple endocrine neoplasia type 2 (MEN-2). We measured plasma catecholamines before and after submaximal exercise in 26 MEN-2 gene carriers, eight of whom with asymptomatic pheochromocytoma, nine with medullary thyroid carcinoma and 10 after uni- or bilateral adrenalectomy. Seventeen clinically healthy individuals and 11 patients with neurovegetative lability and symptoms mimicking pheochromocytoma served as controls. Plasma adrenaline, noradrenaline and dopamine increased after exercise except for adrenaline after bilateral adrenalectomy. The post-exercise levels of adrenaline and the adrenaline/dopamine ratio were significantly higher in the pheochromocytoma patients compared to the healthy controls and the patients with neurovegetative lability, while the patients with medullary thyroid carcinoma represented an intermediate group with a high probability of developing adrenal tumors. The present method is a physiological test with a high sensitivity and specificity. It is practical and well suited for repeated examinations and seems to be of value for the detection of early pheochromocytoma in MEN-2 patients. Furthermore, the test could be used in the differential diagnosis between pheochromocytoma and neurovegetative lability.

Adrenal Gland Neoplasms↗
PubMed1986

Frequency- and reserpine-dependent chemical coding of sympathetic transmission: differential release of noradrenaline and neuropeptide Y from pig spleen.

The importance of impulse pattern and stimulation frequency for the release of noradrenaline (NA) and the coexisting peptide neuropeptide Y (NPY) in relation to vasoconstriction (perfusion-pressure increase) was studied in the blood-perfused pig spleen in vivo. Splenic nerve stimulation with intermittent bursts at high frequency (20 Hz) caused a several-fold larger release of NPY-like immunoreactivity (-LI) in relation to NA than a continuous stimulation at a low frequency (2 Hz), giving the same total number of impulses. alpha-Adrenoceptor blockade by phentolamine enhanced markedly both NA and NPY release, especially at low stimulation frequency, suggesting prejunctional adrenergic inhibition of release. Addition of propranolol unmasked a large remaining perfusion-pressure response to nerve stimulation. Reserpine treatment reduced the NA content of the spleen as well as the stimulation-evoked NA release by greater than 90%. However, the perfusion-pressure increase in response to nerve stimulation was well maintained. A marked increase in the stimulation-evoked release of NPY-LI occurred after reserpine. Adrenoceptor blockade after reserpine treatment reduced only slightly the perfusion-pressure response in parallel with a decline in NPY output. NPY caused an adrenoceptor-resistant perfusion-pressure increase at plasma concentrations that were in the same range as the maximal increase during nerve stimulations. In conclusion, the present data suggest a frequency-dependent, chemical coding of sympathetic transmission with preferential release of the classical transmitter NA at low, continuous frequencies and release of NPY, mainly at high frequencies. Reserpine treatment enhances markedly NPY release, which may explain why the functional response is largely intact in spite of adrenoceptor blockade and marked NA depletion.

Adrenergic Fibers↗
PubMed1986

Constipation a commonly unrecognized cause of enuresis.

Constipation was confirmed by history, rectal examination, and rectal manometric studies in 22 of 25 children with enuresis. Treatment of constipation resulted in resolution of enuresis. Uninhibited bladder contractions, observed in enuretic constipated children, were also noted in children with constipation alone, suggesting that constipation is a commonly unrecognized etiologic factor in enuresis.

Child↗
PubMed1986

Selective venous sampling for localization of hyperfunctioning parathyroid glands.

Selective venous sampling with parathyroid hormone assay was used in 46 patients with primary hyperparathyroidism. All patients had previously been operated on in the neck region. In 80 per cent of the patients the method correctly located the position of the hyperfunctioning gland(s). No complications were observed. The method was found to be of great value when evaluating patients with persistent or recurrent hyperparathyroidism.

Adenoma↗