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Biomedical subjects

J Beyer

Publications and source records attributed to J Beyer.

At least 397 records · Page 22Linked to original sources
PubMed1985

[Improved estimation of parameters of blood pressure regulation in anesthetized dogs].

Estimation of parameters was based on tilting table tests in anaesthetized mongrel dogs. The registered variables were the carotid sinus pressure, aortic and superior vena cava pressure as well as the e.c.g. An orthostatic loading series after experimental designs of first order of Plackett and Burman served as an additional disturbance, which is necessary for a model in a closed loop system. Systemic parameters were estimated from measured data by means of recursive regression and generalized recursive regression. A discrepancy between the excellent animal tests and the quality of the model of subsequent estimation of parameters suggested a filtration of measured data, and a non-linear model (Hammerstein model) was selected for comparison. Contrary to the Hammerstein model, filtration of data led to a considerable improvement of the estimated parameters in the present study.

Anesthesia, General↗
PubMed1984

[Effect of dietary fat on blood sugar levels and insulin consumption after intake of various carbohydrate carriers in type I diabetics on the artificial pancreas].

The role of fat on carbohydrate absorption was investigated in 14 type-I-diabetics who were connected to a glucose-monitored insulin infusion pump (Biostator, Miles). The patients received test meals in the form of potatoes, rice and apples with equal carbohydrate content, in each case with and without added fat. Comparison of carbohydrate carriers showed an increase of blood sugar and insulin consumption which was biggest after the potato meal and significantly lower after rice and apple ingestion. This is probably related to the different biologic availability of carbohydrate carriers. Addition of fat caused lowering of blood sugar and insulin consumption in the potato meal; in this case nutritional fat is likely to have slowed gastrointestinal passage. There were no major differences among rice and apple. It can be concluded that addition of fat delays absorption of rapidly split carbohydrates more than absorption of slowly split carbohydrates such as rice. The lack of influence of fat on postprandial blood sugar and insulin consumption after an apple meal is related to the slight increase of blood sugar caused by the high content of fructose.

Adolescent↗
PubMed1984

Long-acting and selective suppression of growth hormone secretion by somatostatin analogue SMS 201-995 in acromegaly.

In 6 of 7 acromegalic patients a single subcutaneous injection of 50 micrograms of a new octapeptide somatostatin analogue (SMS 201-995) reduced serum growth hormone (GH) from 30 +/- 12 ng/ml to 1.4 +/- 0.4 (mean +/- SEM). Serum GH remained below basal concentration for 9 h. In the remaining patient who had very high basal preprandial serum GH, SMS 201-995 produced a reduction in serum GH of only 20%. Plasma glucose concentrations were increased to the upper limits of the normal range when a high-carbohydrate meal was consumed 2 h after injection. In non-diabetic patients plasma glucose did not exceed 129 mg/dl. The 40% decrease in plasma glucagon, which lasted for 7 h after SMS 201-995 injection, was not statistically significant. No side-effects and no rebound phenomenon were observed. These results suggest that SMS 201-995 may be the first somatostatin analogue suitable for the clinical management of acromegaly.

Acromegaly↗
PubMed1984

[Doppler sonography of extracranial cerebrovascular and peripheral arteries in arteriosclerosis risk factors and in coronary heart disease].

Doppler examination of the neck and limbs of 160 patients with a predisposition to arterial vascular disease in the presence of hypertension, hyperlipoproteinaemia, cigarette smoking and diabetes mellitus, 66% of whom had a combination of two or more of these risk factors, showed in 48 cases single or combined lesions in the arteries of the neck. One patient had unilateral stenosis of the common carotid artery; 20 patients showed unilateral and seven bilateral stenosis of the internal carotid artery; nine patients had unilateral and two patients bilateral stenosis of the external carotid artery; 28 patients showed unilateral flow reduction in the vertebral artery. There was a combined lesion of two or three vessels of the neck in 12 patients. Stenotic peripheral arteries at different levels of the leg with ankle pressure index decrease of up to 22.5% were detected in 54 patients.These peripheral arterial diseases were associated with stenotic carotid arteries in 28%. Peripheral vascular lesions were present in 40% of patients stenotic carotid arteries. Of the 160 patients studied 67 had proven coronary heart disease; 22% of these showed stenotic carotid arteries and 29% showed stenotic peripheral arteries. Combined lesions of the coronary, carotid and peripheral arteries were found in 13%.

Adult↗
PubMed1984

Prolonged application of pressure in transluminal coronary angioplasty.

We investigated the morphologic structure and fluid content of atherosclerotic specimens of fresh human postmortem artery segments before and after application of a pressure of 5 atmospheres simulated by a weight of 5 kg per 1 cm2. After applying pressure in nonorganized atheromata, we noticed a marked reduction in thickness while in fibrotic atheromata we observed only smaller differences in thickness. Reduction in fluid content was significantly more pronounced in nonorganized atheromatous tissue. Reduction in thickness was closely related to reduction in weight (i e, fluid content). The time of pressure application necessary to achieve the optimal result averaged 60 sec. The conclusions drawn from these experiments were incorporated into clinical application of coronary angioplasty. Prolonged balloon inflation was applied to the last 400 out of a total of 600 coronary angioplasty procedures, performed between October 1977 and October 1983. Stenoses not sufficiently responsive to balloon inflation periods of 5-10 sec were exposed to periods of 60 sec (30-120 sec). The number of "non dilatable" stenoses was 15% with the standard short pressure procedure, but only 5% with the prolonged pressure application. No serious complications related to prolonged pressure application were observed. Thus, from experimental data and clinical experience the application of longer pressure periods appears justified and beneficial.

Angioplasty, Balloon↗
PubMed1984

Development of individual insulin infusion profiles for open loop infusion systems.

A computer controlled syringe-type insulin infusion pump storing up to 254 different infusion rates, eight different meal programs and two different basal rates automatically changeable during 24 h in EPROM was used for insulin infusion applying a wavy step profile. This profile approaching the physiological postprandial insulin secretion of the B-cell was calculated by an algorithm following the biphasic insulin secretion model proposed by E. Cerasi . The computer program for the open loop infusion device simulated the feed-back structure of a closed loop insulin secretion control by an algorithm based upon a theoretical postprandial blood sugar profile. Fifteen unstable juvenile onset insulin requiring diabetics could be well controlled after two to three days of an intravenous open loop insulin infusion program. The programs consisted of two constant basal rates and superimposed wavy step profile programs activated at the beginning of each meal. The preabsorptive bolus or cephalic phase was an additional tool both for improved postprandial blood sugar control and further reduction of insulin consumption. The programmable insulin infusion device proved as a valuable tool for the study of a sophisticated insulin infusion profile suitable as well for open loop as for closed loop insulin infusion systems.

Adult↗
PubMed1984

[Percutaneous transcatheter ablation of parathyroid gland tumors by alcohol injection and contrast media infusion].

An attempt to obliterate the parathyroid glands by a catheter technique has been made in three patients with primary hyperparathyroidism. Two mediastinal tumours were defunctionalized with alcohol, and followup for 11 and 13 months showed that it had been successful. One cervical parathyroid tumour was over-injected with contrast medium, but there was a recurrence after 14 months, as indicated by rising serum calcium and parathormone levels. In selected cases the method may be an alternative to surgery, particularly in patients where previous surgery had been unsuccessful or if there is a high operative risk.

Adenoma↗
PubMed1984

[Technic of real-time ultrasonic examination of the adrenal glands and adrenal gland tumors].

A prospective examination was carried out to determine the optimum technique for demonstrating the adrenal glands; there were 60 normal persons, 16 with small adrenal tumours (average size 13 mm.) and 10 with large adrenal tumours (average size 38 mm.). A normal adrenal gland was identified only once amongst the 60 patients as a hypoechoic structure. Fifteen of the 16 small, and eight of nine large tumours could be demonstrated sonographically. An intercostal approach was particularly suitable for showing the suprarenal region and for small tumours. Large tumours could be shown by a ventral, lateral or dorsal approach.

Adenoma↗
PubMed1984

Effect of cimetidine on basal and histamine-induced secretion of parathyroid hormone in vitro.

The effect of cimetidine on basal and histamine-induced PTH secretion was tested using single cell suspensions obtained from (a) primary parathyroid adenomas, and (b) secondary hyperplastic parathyroid tissue from patients undergoing chronic hemodialysis. The histamine-stimulated hormone secretion was dose-dependent. Cimetidine suppressed both basal and histamine-stimulated hormone secretion. Within the therapeutic range the suppressive effect was identical for adenoma and hyperplasia. Both adenomata and secondary hyperplastic glands showed a histamine H2-receptor-related response. The role of histamine in the pathogenesis of hyperparathyroidism is not quite clear so that the possible benefits of cimetidine for medical treatment of primary and secondary hyperparathyroidism will have to be proven by careful clinical trials.

Adenoma↗
PubMed1983

[CEA determination to differentiate between pheochromocytoma with ectopic calcitonin formation and type-II multiple endocrine neoplasms].

Plasma levels of calcitonin and carcinoembryonic antigen (CEA) were determined pre-operatively and two months postoperatively in ten patients with C-cell carcinoma as part of multiple endocrine neoplasia type II. In addition, CEA was measured in extracts from 20 different phaeochromocytomas (five from patients with multiple endocrine neoplasia type II, 15 from patients with sporadic phaeochromocytoma). In comparison, CEA concentration was determined in extracts from five C-cell carcinomas of patients with multiple endocrine neoplasia type II. When correlating pre- and postoperative calcitonin and CEA levels, there was a significant linear relationship (P less than 0.001). CEA concentration in extracts from phaeochromocytomas was at the lower level of sensitivity (4.7 +/- 12.2 pg/mg tumour wet-weight). In extracts from C-cell carcinomas they were much higher (6402 +/- 4570 pg/mg tumour wet-weight). The results suggest that it is possible, in patients with phaeochromocytoma and high calcitonin levels, to differentiate by additional CEA determination between C-cell carcinoma in the course of multiple endocrine neoplasia type II and sporadic phaeochromocytoma with ectopic calcitonin liberation.

Adrenal Gland Neoplasms↗