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Biomedical subjects

M Ziegler

Publications and source records attributed to M Ziegler.

At least 289 records · Page 16Linked to original sources
PubMed1986

Central muscarinic effects of physostigmine on mood, cardiovascular function, pituitary and adrenal neuroendocrine release.

The mechanism by which physostigmine exerts its behavioral, neuroendocrine and cardiovascular effects was explored in two separate experiments. In the first, the centrally-acting cholinesterase inhibitor physostigmine was compared with the non-centrally-acting agent neostigmine. In contrast to physostigmine, neostigmine caused no effects. In the second experiment, pretreatment with scopolamine, in contrast to methscopolamine, attenuated physostigmine's effects. The results suggest that physostigmine exerts its effects via a central muscarinic mechanism.

Adrenal Cortex↗
PubMed1986

Immunocytochemical detection of peptides in the guinea pig cochlea.

The cochleae of juvenile guinea pigs were investigated for the presence of several neuropeptides. Glucagon, insulin, CCK and beta-endorphin immunoreactive neurons and nerve fibers as well as hair cells were demonstrated by the peroxidase antiperoxidase technique. Small amounts of substance P were also found in different sites in the inner ear. In contrast, prolactin-like material could not be found at all. These findings have significance with regard to the putative role of neuropeptides in neuromodulation.

Animals↗
PubMed1986

Central and peripheral cholinesterase inhibition: effects on anterior pituitary and sympathomimetic function.

Ten physically healthy inpatients of mixed diagnosis received, in a randomized, counterbalanced double-blind paradigm, physostigmine (22 micrograms/kg) and neostigmine (11 micrograms/kg). Infusions were separated by at least 2 days. The differential effects of physostigmine and neostigmine on plasma concentrations of cortisol, prolactin, growth hormone, ACTH, beta-endorphin/beta-lipotropin-like immunoreactivity, dopamine, norepinephrine, and epinephrine are reported. Administration of physostigmine, unlike that of neostigmine, was associated with statistically significant increases in plasma concentrations of cortisol, prolactin, ACTH, beta-endorphin/beta-lipotropin-like immunoreactivity, and epinephrine, presumably via central mechanisms. In a separate study, 15 subjects, mostly depressed inpatients, were pretreated with methscopolamine (0.75 mg) on one day and scopolamine (0.5 mg) on another day, at least 2 days apart, in a randomized, counterbalanced double blind paradigm and subsequently on each day received physostigmine (22 micrograms/kg). Scopolamine significantly attenuated the physostigmine-associated increase in plasma concentrations of cortisol, growth hormone, prolactin, ACTH, and dopamine compared to methscopolamine, and a close-to-significant attenuation of epinephrine as well. These results provide further evidence that physostigmine's effects on plasma concentrations of pituitary hormones and epinephrine occur via central mechanisms and are muscarinically mediated.

Adrenocorticotropic Hormone↗
PubMed1986

A mouse model for the study of necrotizing enterocolitis.

A mouse model for the study of necrotizing enterocolitis is presented. It is a model of temporary intestinal ischemia and consists of occluding both superior mesenteric vessels with a bulldog clamp for varying periods of time. The resultant lesions resemble the intestinal lesions seen in necrotizing enterocolitis in respect to the gradual development of the necrotizing lesions and their patchy distribution. We also studied the effect of intravenous saline and low molecular weight dextran in preventing the development of these ischemic lesions. In moderate ischemia, saline and dextran show a similar protective effect, and in severe ischemia, both show a protective effect, with dextran being more effective than saline.

Animals↗
PubMed1986

Neuropeptides in macula utriculi and macula sacculi of guinea pig labyrinth. An immunohistochemical study.

The neuropeptides Substance P, beta-Endorphin, Prolactin, Cholecystokinin, and Glucagon were investigated by means of Sternbergers PAP technique in the neuroepithelium of the Maculae utriculi and sacculi of the labyrinth of newborn guinea pigs. This brief report will show the localization of some neuropeptides in the neuroepithelium of the Maculae utriculi and sacculi. We could not find information about similar studies on this topic in the literature. In connection with investigations of the sensory apparatus of the inner ear we have recently presented neuropeptides evidence for the presence of certain peptides in the Ggl. spirale and the hair cells of the organ of Corti. With this paper we continue to report on neuropeptides in the labyrinth of the juvenile guinea pig as revealed by immunohistochemistry (Nowak et al., in press).

Acoustic Maculae↗
PubMed1986

The role of insulin antibodies in insulin treatment of type I diabetes.

We investigated equilibrium plasma binding patterns of insulin in 45 juvenile diabetics treated with conventional insulin preparations. Insulin binding parameters were evaluated by Scatchard analysis of the binding data. Stable diabetics had significantly lower equilibrium dissociation constants than labile, thus suggesting an enhanced insulin depot effect due to stronger insulin binding. Correlation of insulin binding data with a glycemic control index yielded a positive relationship between insulin antibody binding and the degree of glycemic control. Insulin neutralization as detected by a relationship between maximum binding capacity of high affinity antibodies and insulin requirement could only be found if patients with poor diabetes control were excluded. Similarly, the well-known promoting influence of residual beta-cell functional capacity (assessed by C-peptide levels) on diabetic stability was observed only after exclusion of patients with higher insulin antibody binding. These data suggest that insulin antibodies are influencing insulin treatment of diabetics in a dual way. They may neutralize therapeutic insulin but at the same time they exert an insulin-sparing action by improvement of diabetes control. Occasionally the latter effect may abolish the correlation between diabetes control and beta-cell functional capacity.

Adolescent↗
PubMed1986

Measurement of insulin during isolation and purification from animal pancreas. A comparison of radioimmunoassay, radioreceptor assay and in-vivo bioassay.

For the purpose of monitoring the yield of the insulin extraction procedure from animal pancreas three methods of insulin determination were compared, i.e. the mouse convulsion test, a radioreceptor assay (RRA) on rat fat cells and a radioimmunoassay (RIA) which was especially laid out for high insulin concentrations. In samples containing actually insulin in general all three methods provided comparable results. Notable differences were only found in proinsulin-containing material. Because of its simplicity and high reproducibility as well as the good agreement of its results with those obtained with the other assays, the RIA turned out to be the most suitable assay. On the other hand, the RRA should be useful in detecting molecular differences between the investigated insulin-like preparations and standard insulin.

Animals↗
PubMed1986

[Animal experiment studies on improving ischemia tolerance of the testis].

The reactions of the germinative testicular epithelium after definite ischemia periods were studied in rats. Using heparin the testicular ischemia tolerance has already been prolonged; this can be distinctly improved by adding alphareceptor blockers. The consequences of a 30 min and 2 h period of testicular ischemia are nearly eliminated by the described medicamentous combination. The experimental results show that at present the use of heparin and alpha-receptor blockers seems to be the best way, to extend the ischemia tolerance during autotransplantation of testicles.

Adrenergic alpha-Antagonists↗
PubMed1986

[In vitro and in vivo effect of gold thioglucose on the insulin- and glucagon-secretion of the isolated perfused rat pancreas].

Effects of gold thioglucose on the insulin and glucagon secretion by the isolated perfused pancreas of Wistar rats in vivo and in vitro Gold thioglucose (GTG), hitherto administered predominantly to mice can also be used in rats in a non toxic dosage, if GTG is injected intravenously (i.v.) together with sodium hexobarbital. Wistar rats tolerate a single injection of GTG in doses ranging from 40 to 1200 mg/kg bw. GTG (10 mmol/l in the perfusion medium) has no in vitro effect--tested by the isolated perfused rat pancreas--on the basal (5.5 mmol/l glucose) or stimulated (11 mmol/l glucose) insulin (IRI)-secretion. This is valid also for glucagon (IRG)-secretion. After in vivo injection of GTG (600 mg/kg bw, together with sodium hexobarbital (10 mg/100 g bw, i.v.] extensive alterations of IRI- and IRG-secretion result as tested under in vitro conditions in the isolated perfused pancreas of the rat, Glucose stimulation (11 mmol/l) causes a hyperinsulinism and a hypersecretion of IRG, a so-called paradoxical glucagon secretion, lasting for 2 days while IRI secretion is already diminished. At the same time food intake is very low and the body weight decreases. Ten days later the body weight has reached the starting value again and the IRI secretion shows again signs of hyperinsulinism. Six months after a single injection of GTG (600 mg/kg bw, i.v.) the rats were obese and react after glucose stimulation with hyperinsulinism and again with a paradoxical glucagon secretion. The blood glucose levels were normoglycaemic, whereas serum IRI rose in parallel with development of the obesity. Also with histological methods we could distinguish an acute from a chronic phase of GTG toxicity visible in the tested organs (liver, kidney, thyroid gland). The endocrine pancreas reacts after a single injection of GTG with a lowered number of B cells. The remaining cells reveal variable amounts of degranulation. In the early phase the hypothalamus, in particular the ventromedial hypothalamic nucleus, shows most clearly signs of destruction and 6 months after a single injection of GTG the number of cells is still reduced in this region. We conclude that GTG reacts primarily on the hypothalamus and modulates the reactivity of the endocrine pancreas in a permanent manner via the vegetative nervous system, because we test the function of the pancreas in an in vitro system. As a consequence the threshold of the B and A cell against the stimulus glucose is altered in two ways.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1986

[Disintegration of kidney calculi with a piezoelectric instrument system. Initial clinical experiences].

Since December 1985 extracorporeal piezoelectric renal lithotripsy has been tested in humans. Up to now 50 patients with renal calculi have been treated. The lithotriptor consists of a special mobile table with an opening in the surface to apply shock waves. Urinary calculi are located by integrated ultrasound location systems. As the piezoelectrically generated high-energy sound pulse does not cause pain, treatment is possible without anesthesia. Permanent ultrasonic control of the stones in the focus during lithotripsy allows effective application of shock waves. With this piezoelectric system the electrocardiogram does not have to be triggered. So far the results have been encouraging and following these tests clinical application is expected to be successful.

Humans↗
PubMed1986

Kinetic properties of monoclonal insulin antibodies.

We investigated four insulin-specific hybridoma antibodies with respect to their kinetic properties as well as the binding behaviour of some combinations of them. From equilibrium binding data all but one antibodies were shown to bear homogeneous binding sites. They revealed homogeneity of binding sites also by kinetic experiments, thus with high probability being monoclonal. At 0 degree C, two of them showed discrepancies between kinetic and steady state binding data in as much as, at steady state, the measured bound-to-free ratio of tracer insulin was 3-4 times lower than calculated from kinetic data. Thus a simple bimolecular reaction mechanism could possibly not be applicable. Mixing two monoclonal insulin antibodies, neither cooperative nor additive binding to the insulin molecule could be observed but only competitive effects. Especially, no positive cooperativity between two or more antibodies could be detected, which would be able to account for the higher affinity usually observed for polyclonal vs. monoclonal antibodies.

Animals↗
PubMed1985

Effect of antibody-mediated crosslinking of insulin on its bioactivity and receptor binding.

Precipitating anti-insulin antibodies or anti-insulin IgG/anti-IgG complexes bind insulin in a highly aggregated form and thus should preferably be capable of inducing receptor aggregation, which has recently been suggested to be a precondition for insulin bioactivity. We, therefore, studied the influence of antibody-mediated crosslinking of insulin on the glucose conversion into CO2 in rat fat cells and glycogen synthesis in rat liver cells. As far as possible receptor-bound insulin was measured in parallel. Insulin bound to antibodies with low insulin precipitating capacity had no or little bioactivity and receptor reactivity on fat cells. The bioactivity, however, could be restored in part by addition of a second antibody. On liver cells, second antibody-mediated crosslinking of insulin-antibody complexes resulted in an enhancement of receptor reactivity, and insulin bioactivity of such crosslinked immune complexes was demonstrable. An insulin-precipitating antiserum was shown to form insulin-antibody complexes with significant bioactivity in fat cells which correlated with their receptor binding. In each case antibodies had no or little effect in the absence of insulin. Our data suggest that insulin neutralization by antibodies can be compensated by crosslinking the insulin-antibody complexes or by formation of big complexes precipitating by themselves. This is probably due to the induction of receptor aggregation.

Adipose Tissue↗