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Biomedical subjects

J Beyer

Publications and source records attributed to J Beyer.

At least 415 records · Page 23Linked to original sources
PubMed1983

Islet-cell tumors: detection of small lesions with computed tomography and ultrasound.

Fifteen patients with a total of 16 islet-cell tumors 7-20 mm in diameter (average, 12 mm) were examined preoperatively by computed tomography (CT) and ultrasound. Seven out of 16 tumors were detected by CT and 9 out of 15 by ultrasound. Marked contrast enhancement was seen on dynamic CT scans following a bolus injection, while a circumscribed, hypoechoic mass was seen on ultrasound. Tumors of the tail of the pancreas and those outside the pancreas were difficult to detect. Ultrasound is recommended as the initial step for locating islet-cell tumors, followed by CT; angiography and transhepatic venous sampling should be restricted to tumors which are not detectable by other methods. Intraoperative ultrasound was successful in 3 patients and may facilitate the operative search.

Adenoma, Islet Cell↗
PubMed1982

[Imaging adrenergic tumours with 131J-meta-benzylguanidine].

Pheochromocytoma scanning using 131J-meta-benzylguanidine was done in one patient with metastasizing paraganglioma, one patient with multiple endocrine neoplasia type IIb. No activity of tumour tissue could be demonstrated in the patient with metastasizing paraganglioma, whereas the pheochromocytoma could be clearly defined in the patient with multiple endocrine neoplasia type IIa. The female with multiple endocrine neoplasia type IIb showed a suspect space-occupying lesion of the left adrenal using computed tomography. Pheochromocytoma could be excluded by 131J-benzylguanidine scanning, selective estimation of catecholamines in adrenal venous blood as well as the glucagon stimulation and clonidine suppression.

Adrenal Gland Neoplasms↗
PubMed1982

[Ectopic hormone formation in multiple endocrine type IIa neoplasia (author's transl)].

A patient with high-grade osteoporosis had elevated levels of ACTH, cortisol and carcinoembryonic antigen (CEA). Computed tomography demonstrated enlarged adrenal glands. Despite intensive search no ACTH-producing tumour was found. A central Cushing's syndrome was thus possible, and a radiologically normal sella turcica made a microadenoma of the hypophysis a possibility. However, a one-time hypertensive crisis with elevated catecholamines raised the suspicion of an additional phaeochromocytoma and thus provided the first pointer to a multiple endocrine neoplasia. Bilateral phaeochromocytomas, discovered at adrenalectomy, as well as raised serum-calcitonin levels, strongly suggested coexistence of a C-cell carcinoma, which previously had not been demonstrated either by thyroid scanning or fine-needle biopsy. A total thyroidectomy revealed a multifocal and metastasizing C-cell carcinoma. On extraction it contained a high concentration of calcitonin, typical for a C-cell carcinoma. An unusual finding was of ACTH in extracts of both the C-cell carcinoma and the phaeochromocytoma. It was immunologically identical with the synthetic ACTH used as a standard.

Adrenal Gland Neoplasms↗
PubMed1982

[Diagnosis of the site of insulinomas: percutaneous transhepatic portal vein catheterisations with selective blood sampling for hormone determination (author's transl)].

Percutaneous transhepatic portal vein catheterisation with blood sampling from the various areas of drainage, especially the pancreatic veins, was undertaken in seven patients with insulinoma to diagnose its site. In six patients measurement of serum-insulin levels revealed an abrupt rise in the vascular area later found to drain the area of the insulinoma. Insulin measurement in one patient with insulinoma in the head of the pancreas falsely indicated an islet-cell tumour in the region of the tail of the pancreas. C-peptide concentration in serum followed the concentration of insulin, but did not show such a marked rise. The method of percutaneous transhepatic portal vein catheterisation with selective blood sampling for the measurement of hormonal concentration was superior to ultrasound, computer tomography or coeliacography for determining the site of the tumour.

Adenoma, Islet Cell↗
PubMed1982

The influence of PEEP ventilation on organ blood flow and peripheral oxygen delivery.

In an experimental study including 10 dogs with intact lungs (group I) and 10 dogs with oleic acid-induced pulmonary edema (group II), the effects of PEEP 10 and 20 (cm H20) on central hemodynamics, lung function, organ blood flow and tissue PO2 (liver and skeletal muscle) were examined. In both groups, PEEP resulted in a significant fall of cardiac output (CO) despite volume substitution. In group I, flow was redistributed favouring brain, heart, kidneys, and adrenals, at the expense of stomach, pancreas and and thyroid gland. Animals with pulmonary edema and consequently lower absolute values of CO showed a more uniform reduction of organ perfusion sparing only brain and heart PEEP 10 led to a marginal improvement of tissue oxygenation, whereas PEEP 20 resulted in a deterioration of local PO2 associated with a decrease in O2 transport. It is concluded that whenever PEEP is applied, a reduction and redistribution of CO may occur possibly jeopardizing tissue oxygenation and thus interfering with organ function.

Animals↗
PubMed1982

Therapeutic pacing in tachyarrhythmias by implanted pacemakers.

Termination of tachyarrhythmias by electrical stimulation has been demonstrated by clinical and experimental evidence. Implantable devices for repetitive use in long-term therapy are so far not readily available. Twelve patients with drug resistant ventricular (3) or supraventricular (accessory pathway (2), atrial flutter (3), junctional tachycardia (3), supraventricular tachycardia (1) tachyarrhythmias are reported in whom, after electrophysiological analysis of the individual tachycardia, a specially designed stimulation system was implanted. Cardiac pacing was performed in the right atrium or ventricle. Stimulation rate was in the range of 150-1016/min. In automatic ECG-controlled devices (2 patients), the number and length of cardiac cycles served as parameters for discharging the stimulation circuit. In 10 patients the antitachycardia-pacemaker was in use as a patient-activated or externally triggered device or as a fixed rate unit. After pacemaker implantation we observed a significant decrease in incidence and/or duration of tachycardic episodes in all patients. In two patients atrial pacing (80 and 90/min) suppressed tachycardias completely. Additional antidysrhythmic drug therapy was necessary in 11 out of our 12 patients. It is concluded that cardiac stimulation with implanted antitachycardia pacemakers can be an efficient long-term antitachyarrhythmic therapy in selected patients.

Adolescent↗
PubMed1982

Influence of norepinephrine on vessel geometry of the intact femoral artery in juvenile insulin-dependent diabetics-evidence of early diabetic angiopathy in central arteries.

A modified M-mode ultrasound echo system had been employed to study blood-vessel geometry of the intact femoral artery before and after Norepinephrine (NE) infusion. 14 patients with juvenile IDDM aged below 35 years and 11 healthy subjects participated in the study. In the diabetic group, wall distensibility (delta D/delta P) was reduced (p less than 0.01) at control conditions. After NE infusion, wall distensibility decreased in both groups (p less than 0.01). The decrease of wall distensibility is due to an increase in pulse pressure (delta P) (p less than 0.002) in the diabetic group and a reduction of pulsatile diameter (delta D) (p less than 0.02) in the normal group. Increased stiffening of the arteriaL wall after NE infusion with progressive reduction of wall strain (delta D/Dd) is the typical finding in the normal group. No change of wall strain was observed in the diabetic group. The functional alteration of the diabetic femoral artery may be described as diminished resistance of the arterial wall to the distending force of rising blood pressure.

Adolescent↗
PubMed1981

[Blood-sugar-controlled insulin infusion systems for rapid adjustment of insulin-dependent diabetics (author's transl)].

Empirically obtained data could be verified and the basis for assessment of total insulin requirement, circadian distribution of insulin doses and contents of single insulin portions of old and delayed-action insulin could be established in a prospective study in 13 insulin-dependent diabetics. Assessment of insulin requirements was done after a 36-hour investigation period with the artificial endocrine pancreas using standardised conditions. Readjustment was complemented by dietary advice and rearrangement of total calory input and distribution of carbohydrates during the day. Therapeutic success in 55 patients justifies this procedure. Adjustment of insulin-dependent diabetics was thus obtained more rapidly, better and at less cost.

Adolescent↗
PubMed1981

[The effect of PEEP ventilation on hemodynamics and regional blood flow (author's transl)].

The beneficial effects of PEEP on lung function may be counteracted by its hemodynamic sequelae induced by a reduction of venous return due to the elevated intrathoracic pressure, and by an increased right ventricular afterload secondary to the rise of pulmonary vascular resistance. PEEP redistributes cardiac output in favor of brain, heart, adrenals and intestines, whereas the perfusion of stomach, pancreas and thyroid is diminished out of proportion to the fall of cardiac output. Total renal blood flow is relatively little affected; however, redistribution of intrarenal blood flow will result in a marked salt-water-retention. Reduction of hepatic artery flow, at higher levels of PEEP, may jeopardize liver tissue oxygenation. - Under clinical conditions, individual differences regarding preexisting cardiopulmonary and peripheral-vascular diseases may modify the PEEP-induced hemodynamic alterations in a wide range.

Blood Circulation↗
PubMed1981

[Diagnosis of focal nodular hyperplasia of the liver (author's transl)].

In two female patients with hypothalamic-hypophyseal Cushing's syndrome who had not taken oral contraceptives, upper abdominal sonography showed three liver tumours as chance findings. In one case the left lobe was involved alone and in one case both lobes. None of the three tumours could be demonstrated by means of computer assisted tomography. Autopsy in one case and liver arteriography and scan in other other led to the diagnosis of focal nodular hyperplasia of the liver. These cases demonstrate the importance of sonography in the recognition of liver tumours. A connection between the overpopulation of adrenocorticosteroids and the formation or enlargement of focal nodular hyperplasia of the liver cannot be excluded.

Adult↗
PubMed1981

The effects of equal caloric amounts of xylitol, sucrose and starch on insulin requirements and blood glucose levels in insulin-dependent diabetics.

Xylitol has been suggested as a potentially useful sweetener in the diabetic diet. In 14 insulin-dependent diabetics a standard diabetic diet regimen was compared with diets in which starch was isocalorically exchanged in the breakfast meal by either 30 g xylitol or 30 g sucrose. Insulin requirement and blood glucose were measured using a glucose-controlled insulin infusion system. The results following breakfast with xylitol were similar to those after starch breakfasts. Sucrose, in contrast, induced a greater post-prandial rise in blood glucose levels despite counter-regulation by the glucose-controlled insulin infusion system. Insulin requirement after sucrose significantly exceeded (p less than 0.01) that after xylitol or starch during the first 60 min and 2 h respectively. No short-term side effects of xylitol were found.

Adult↗
PubMed1981

[Localization of islet cell tumors using sonography, computed tomography, arteriography and selective transhepatic venous sampling for hormone assay (author's transl)].

Of 29 patients examined operation revealed a malignant tumor in 9 and a benign insulinoma in 18, 2 insulinomas were not found. The problems of preoperative tumor localization were limited to small insulinomas (size 7-35 mm). Ultrasound detected all of 3 insulinomas as low echogenic structures (size 7, 8, 17 mm). Computed tomography demonstrated 4 of 5 insulinomas (size 7, 8, 15, 17 mm) due to contrast enhancement following bolus injection. Arteriography localized 12 of 18 insulinomas preoperatively and 14 of 18 retrospectively. Selective transhepatic venous sampling for insulin assay identified 7 of 8 tumors. Real-time ultrasound and dynamic CT are promising in the diagnostics of insulinomas over 7 mm and should precede arteriography. Selective transhepatic venous sampling as the last diagnostic step is a major procedure and most specific, but not always without problems in interpretation.

Adenoma, Islet Cell↗