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Biomedical subjects

E Werle

Publications and source records attributed to E Werle.

At least 19 recordsLinked to original sources
PubMed1992

The clinical significance of measuring different anti-dsDNA antibodies by using the Farr assay, an enzyme immunoassay and a Crithidia luciliae immunofluorescence test.

Anti-double-stranded DNA (dsDNA) antibodies are highly specific for the diagnosis of systemic lupus erythematosus (SLE) but are heterogeneous in respect to, for example, avidity, class and cross-reactivity. Sera from 2061 patients were measured by three methods: an enzyme-linked immunosorbent assay (ELISA), an indirect immunofluorescence test with Crithidia luciliae as substrate (CLIF), and the Farr assay, a radioimmunological method based on the ammonium sulfate precipitation of immune complexes. The different anti-dsDNA antibody determinations were evaluated by analysis of patient records. The reason for a reactive Farr assay in 14 patients was predominantly the measurement of antibodies of the IgM class, which are not detected by the ELISA. The detection of additional antibodies to dsDNA of the IgA class, to single-stranded DNA or to histones plays a minor role. In comparison with the Farr assay, we found more positive results with the ELISA, which additionally detects anti-dsDNA antibodies of low avidity. The ELISA might also yield positive values in conditions such as chronic liver diseases, various infections and connective tissue diseases other than SLE. Avoiding the disadvantages of radioactivity, the ELISA is well suited as a screening test for dsDNA antibodies. However, positive results should be confirmed by the CLIF test or preferably by the Farr assay, thus combining sensitivity with specificity.

Animals↗
PubMed1991

Sympathetic neuronal activity in diabetic and non-diabetic subjects with peripheral arterial occlusive disease.

Despite the vasoconstrictory influence of the alpha-adrenergic system on the peripheral blood circulation the results of the sympathectomy were not satisfying in the therapy of peripheral arterial occlusive disease (PAOD). The aim of the present investigation was to clarify the pathophysiologic mechanisms of this clinical observation. Free and sulfoconjugated catecholamines were determined in the femoral artery, vein, and cubital vein of 19 healthy controls, 21 non-diabetic patients with PAOD stage II, 8 non-diabetic (PAOD IV) and 20 diabetic patients (D IV) with PAOD stage IV. In comparison with controls and group PAOD II an increased sympathoneuronal tone in group PAOD IV was evident at rest. Sympathetic activation was not restricted to the affected limb, since femoral and cubital venous norepinephrine levels were not different and plasma epinephrine fractional extraction (PEFE) was not altered by angiopathy. The lower sympathoneuronal activation in the group D IV may be attributed to an impaired pain perception or a reduced dopamine beta-hydroxylase activity indicated by a lower ratio of norepinephrine to dopamine. The failing long-term efficacy of lumbar sympathectomy in critical arterial limb disease may be explained by marked spontaneous sympathicolysis in diabetics, whereas in non-diabetics with sympathetic activation other mechanisms like development of unilateral Mönckeberg sclerosis, progression of proximal arterial occlusion or induction of steal effects have to be discussed.

Adult↗
PubMed1991

Interaction between hormones and the immune system.

After a short introduction into the general topic, the catecholamine-induced increase of leukocytes in which the granulocytes are predominant after short-term exercise is discussed. The reduction of lymphocytes is associated with work-dependent cortisol increase after long-term exercise or 1 h after strenous work. The catecholamine-stimulated lymphocytes increase could be explained by the liberation of the cells from the endothelial vessel wall after catecholamine interaction with the beta-adrenoceptors and by mobilization from lymph nodes and spleen after beta-adrenergic stimulation. Catecholamines reduce the proliferation of lymphocytes and the degranulation of mast cells, preventing hypersensitivity reaction due to inhibited mediator liberation. The influence of cortisol and cytokines and vice versa is discussed. The hormonal changes after runs of different intensities and duration are demonstrated; they show an interaction with immunological regulation. The neuroimmune modulation after physical and psychological stress also has to be considered in immune regulation since under this condition the secretion of encephalins, endorphins, ACTH, and cortisol is increased. The significance of enhanced vasopressin secretion causing postural fainting by vagovasal reaction indicates also the effect of a neuropeptide which is related to immunological reactions. In the changes of lymphocyte subclasses, the homing effect of these cells should be regarded. Advices which can improve the immunologic behaviour, avoiding susceptibility to infections by well-conducted training regimens and adequate periods of regeneration time, are necessary.(ABSTRACT TRUNCATED AT 250 WORDS)

Catecholamines↗
PubMed1991

O-Methylated and sulfoconjugated catecholamines: differential activities at human platelet alpha 2-adrenoceptors.

The physiological effects of the sulfoconjugates of epinephrine, norepinephrine, and the 3-O-methylated catecholamines, metanephrine, normetanephrine, and methoxytyramine were examined with regard to their alpha 2-adrenoceptor binding properties and aggregation activity in human platelets. Sulfoconjugation of catecholamines resulted in the loss of both their competitive potency for [3H]yohimbine binding and their influence on platelet aggregation. O-Methyl substituted catecholamines showed attenuation of their alpha 2-adrenoceptor binding affinities when compared with those of the corresponding non-esterified amines. Unlike the free amine epinephrine, which stimulated platelet aggregation, the O-methylated catecholamine derivatives inhibited aggregation. Inhibition was dose-dependent and restricted to the alpha 2-adrenoceptor mediated aggregation response stimulated by epinephrine (1 microM) or potentiated by subthreshold concentrations of epinephrine (30-300 nM) in the presence of subaggregatory doses of vasopressin (10-30 nM). Collagen- and ADP-induced platelet aggregation was not affected. The hydrophilic beta-antagonist CGP 12177 displayed no effects. However, high concentrations (0.1 mM) of both isomers of the strongly lipophilic beta-adrenoceptor antagonist propranolol inhibited the actions of all aggregators by stabilizing the membrane. Such a nonspecific membrane interaction of the methylated catecholamines could be excluded because of their low lipid solubility calculated in a n-octanol-phosphate buffer system at pH 7.4. We suggest therefore that methylated catecholamines are biological alpha 2-adrenoceptor antagonists acting on alpha 2-adrenoceptor stimulated reactions of human platelets. Whether this receptor antagonism is relevant to other human tissues needs clarification. Sulfated catecholamines, however, are wholly ineffective at this receptor site and may constitute a pathway to control the concentration of the active free catecholamines.

Adrenergic beta-Antagonists↗
PubMed1991

[Excretion of beta-N-acetylglucosaminidase in urine in type I and type II diabetic patients with and without nephropathy].

The clinical aspects of the excretion of beta-N-acetylglucosaminidase (beta-NAG, EC 3.2.1.30) in urine of type I and type II diabetics with and without nephropathy are evaluated. Correlation between concentration of albumin and of beta-NAG activity in urine is determined and the circadian rhythm of beta-NAG excretion in urine is examined, the indication of glomerular and tubulointerstitial damage is discussed. Longitudinal studies should demonstrate, whether an increased beta-NAG activity in urine of diabetics with normoalbuminuria is an indicator of nephropathy or a predictor of nephropathy if raised albuminuria is observed.

Acetylglucosaminidase↗
PubMed1990

Purine nucleotides and AMP deamination during maximal and endurance swimming exercise in heart and skeletal muscle of rats.

The purine nucleotides, phosphocreatine (PCr), ammonia, and lactic acid were investigated in skeletal muscles of rats with prominent type I, type IIa, type IIb fibers, and the heart after exhaustive and endurance swimming tests. ATP, ADP, AMP, IMP, and PCr were determined by HPLC with UV detection in controls after maximal and endurance training for 6 weeks with or without a respective final test and also after final exhaustive or endurance test without preceding training. The swimming time in these tests was longer with than without training. A pronounced ATP decrease and a large increase in IMP, up to 4.9 mumol/g wet weight, were found in type IIb fibers after the maximal final test without preceding training. Compared with skeletal muscle, the IMP concentration in the heart was significantly lower after all exercise bouts, even though after maximal exercise AMP augmentation was highest, ATP reduction was greatest, and energy charge was lowest. The difference between the heart and skeletal muscle in the production of IMP indicates that despite AMP and ADP accumulation, myoadenylate deaminase (MAD) activity in the heart is considerably lower than in skeletal muscle, especially in type IIb fibers. The smaller amount of MAD per tissue, and also the different MAD isozyme pattern of the heart as reported in the literature, may be attributed to lower activation. The difference between MAD activation of the soleus muscle and of the iliacus muscle, both consisting predominantly of type I fibers, suggests that MAD activity may be influenced by biochemical demand and oxygen supply, varying with the anatomical localization. Even though ammonia and lactic acid were highly correlated, it is questionable whether the H+ ion increase due to the lactate accumulation itself triggers MAD activation, as has been found for AMP and ADP in skeletal muscle.

AMP Deaminase↗
PubMed1990

Isomer specific kinetics of dopamine beta-hydroxylase and arylsulfatase towards catecholamine sulfates.

Both isomers of epinephrine sulfate were synthesized, unequivocally identified by 1H-NMR and highly purified from catecholamines (less than 90 ppm). Bacterial as well as pig liver arylsulfatase A and B demonstrated a higher substrate turnover of epinephrine-4-sulfate, norepinephrine-4-sulfate and dopamine-4-sulfate as compared to the 3-sulfate isomers. The arylsulfatase B however, is less important for the deconjugation of these sulfoconjugates than arylsulfatase A. Since arylsulfatase A occurs in most human tissues, it might be of physiological significance in the deconjugation of the catecholamine sulfate isomers. Furthermore the kinetic data at pH 7.4 and 6.9 suggest the increased cleavage of the sulfate group, e.g. during exercise-induced acidosis. In contrast to results reported in the literature, dopamine sulfates were no substrates of dopamine beta-hydroxylase.

Animals↗
PubMed1989

[Comparison of 3 latest-generation glucose micro-reflectometers].

Three glucose reflectance meters (Reflolux II = Accu-Chek II, Glucometer II and Hypocount GA) were tested for precision and accuracy when used by medical personnel of a diabetic outpatient department and for self-monitoring at home. In addition, the visual readability of the appropriate reagent strip was checked. All three systems were sufficiently valid for reflectometric reading, while visual evaluation showed a higher deviation. The precision of Accu-Chek II under optimal conditions in the outpatient department was comparable to the precision of laboratory examinations (CV 3.3%). When used by patients themselves, Accu-Chek II and Glucometer II were sufficiently precise (CV 4.8% [corrected] and 5.3% respectively). These devices are recommended for blood glucose self-monitoring.

Adult↗
PubMed1988

Syntheses of the sulfoconjugated isomers of norepinephrine and dopamine, controlled by HPLC with ultraviolet detection.

The physiological significance of sulfoconjugated catecholamines and their involvement in clinical disorders, e.g. hypertension and Parkinsonism, is poorly investigated. For this reason, the sulfoconjugated isomers of dopamine as well as of norepinephrine were synthesized by modified methods. All isomers and their intermediates could be detected by a reversed-phase high-performance liquid chromatography with ultraviolet detection (HPLC-UV) with short retention times and a good reproducibility. Ion-exchange chromatography with an extended column length improved the separation of the reaction products, and the immediate control by HPLC-UV enabled precise cutting of the fractions. The selection of the fractions with the optimum ratios of product/by-product resulted in improved yields and highest purity. All by-products, e.g. dopamine sulfonic acids, were less than 0.04%, as detected by HPLC-UV and, in addition, the contamination by free catecholamines was only 41 x 10(-4)-87 x 10(-4)%, as measured by HPLC with electrochemical detection (HPLC-ED). The purity was further demonstrated in two highly sensitive biological assays: cAMP production in human mononuclear leukocytes and aggregation of human platelets. The sulfoconjugated catecholamines were characterized by melting point, thin-layer chromatography, infrared spectrum, HPLC-UV, elemental analysis, and unequivocally identified by 1H-NMR.

Chemical Phenomena↗
PubMed1988

3- and 4-O-sulfoconjugated and methylated dopamine: highly reduced binding affinity to dopamine D2 receptors in rat striatal membranes.

The binding properties of 3- and 4-O-sulfo-conjugated dopamine (DA-3-O-S, DA-4-O-S) as well as 3-O-methylated dopamine (MT) to rat striatal dopamine D2 receptors were investigated. 3H-spiperone was used as a radioligand in the binding studies. In saturation binding experiments (+)butaclamol, which has been reported to bind to dopaminergic D2 and serotoninergic 5HT2 receptors, was used in conjunction with ketanserin and sulpiride, which preferentially label 5HT2 and D2 receptors, respectively, in order to discriminate between 3H-spiperone binding to D2 and to 5HT2 receptors. Under our particular membrane preparation and assay conditions, 3H-spiperone binds to D2 and 5HT2 receptors with a maximal binding capacity (Bmax) of 340 fmol/mg protein in proportions of about 75%:25% with similar dissociation constants KD (35 pmol/l; 43 pmol/l). This result was verified by the biphasic competition curve of ketanserin, which revealed about 20% high (KD = 24 nmol/l) and 80% low (KD = 420 nmol/l) affinity binding sites corresponding to 5HT2 and D2 receptors, respectively. Therefore, all further competition experiments at a tracer concentration of 50 pmol/l were performed in the presence of 0.1 mumol/l ketanserin to mask the 5HT2 receptors. DA competition curves were best fitted assuming two binding sites, with high (KH = 0.12 mumol/l) and low (KL = 18 mumol/l) affinity, present in a ratio of 3:1. The high affinity binding sites were interconvertible by 100 mumol/l guanyl-5-yl imidodiphosphate [Gpp(NH)p], resulting in a homogenous affinity state of DA receptors (KD = 2.8 mumol/l).2+ off

Animals↗
PubMed1988

Modified syntheses of dopamine-4-sulfate, epinephrine-3-sulfate, and norepinephrine-3-sulfate: determination of the position of the sulfate group by 1H-NMR spectroscopy.

With respect to the growing interest in sulfoconjugated catecholamines (CAS), reliable syntheses of those substances including high purification and unequivocal identification are required. For the syntheses of the 3-O-sulfates of norepinephrine (NE) and epinephrine (EPI), modifications of the methods of Stolz (12) and Arakawa et al. (1) were performed. Noradrenalone and adrenalone were prepared according to the method of Stolz (12) and sulfated by reaction with pyridine-sulfurtrioxide complex in dry pyridine at 60 degrees C. After reduction of these ketosulfates by sodium borohydride in dry pyridine, NE-3-O-S and EPI-3-O-S were obtained respectively. We synthesized dopamine-4-O-sulfate (DA-4-O-S) by reaction of DA hydrochloride with pyridine-sulfurtrioxide complex in dry dimethylformamide at 20 degrees C (Harbeson et al., 1983). The highly purified products (DA-4-O-S, NE-3-O-S, EPI-3-O-S) were characterized by their melting points (mp), infrared spectra (IR), thin-layer chromatography (TLC), high-performance liquid chromatography (HPLC), elemental analysis, and 1H-nuclear magnetic resonance spectroscopy (1H-NMR).

Dopamine↗
PubMed1988

Restricted alpha- and beta-adrenoceptor affinity of sulfoconjugated catecholamines in human mononuclear leukocytes, platelets, and fat cells and reduction of the postreceptor mechanisms.

The physiologic significance of the racemic 3-O-sulfate esters of epinephrine (EPI-3-O-S) and norepinephrine (NE-3-O-S) as well as 4-O-sulfoconjugated dopamine (DA-4-O-S) was evaluated. For this purpose these conjugated catecholamines (CA) were synthesized and investigated with respect to their alpha 2- and beta 2-adrenoceptor affinities and their biological activity in three different human cell systems: in mononuclear leukocytes (MNL), platelets, and fat cells. The unequivocal identification and the minimal degree of contamination of the synthesized sulfoconjugates with free CA was proved by 1H-NMR and by high-performance liquid chromatography with amperometric detection (HPLCA) respectively. In isolated human MNL, beta-adrenoceptor affinities of these conjugated CA were determined in competition experiments with the lipophilic nonspecific radioligand (-) 125I-cyanopindolol (ICYP) and, in addition, with the hydrophilic ligand 3H-CGP12177. With both ligands the affinity constants (KD) of the sulfoconjugated CA under investigation were about 100- to 1000-fold higher when compared with the respective free amines. Moreover, these sulfoconjugated CA per se induced no intracellular production of cyclic adenosine monophosphate (cAMP) in MNL. In comparison with the free amines, metanephrine (MN) and normetanephrine (NMN) showed a highly reduced competitive potency on the MNL beta-adrenoceptors labelled with 3H-CGP or ICYP. The KD values for MN and NMN in competition studies with ICYP were 10- and 5-fold higher than in those with 3H-CGP respectively, indicating a restricted access of MN and NMN to intracellular receptors. The adenylate cyclase system was not stimulated at all by MN or by NMN. In human platelets EPI-3-O-S and NE-3-O-S neither competed with the specific alpha 2-adrenoceptor antagonist 3H-yohimbine nor elicited any aggregation response at all. MN and NMN exhibited an about 40-fold reduced affinity for alpha 2-adrenoceptors in platelets when compared with the respective free amines and elicited no aggregation response at all. However, in the presence of MN and NMN the EPI- and NE-induced platelet aggregation was dose-dependently attenuated. These findings reveal an alpha 2-adrenoceptor antagonistic potency of MN and NMN. In human adipocytes EPI-3-O-S and NE-3-O-S were 100- to 1000-fold less potent to inhibit lipid mobilization via alpha 2-adrenoceptors as well as to stimulate the beta-adrenoceptor mediated lipolysis when compared with free CA.

Adipose Tissue↗
PubMed1988

Influence of exercise in water on hormonal, metabolic and adrenergic receptor changes in man.

We investigated hormonal, metabolic, and cardiovascular adaptations as well as changes of alpha 2- and beta 2-adrenergic receptors in response to three different exercise performances in water: 1000 m fin swimming with or without a neoprene suit and, additionally, 600 m diving with a breathing apparatus while performing several tasks. Eight male divers participated in the study. Blood samples were taken at rest on land, 10 min after water immersion, immediately after exercise, and after 20 min recovery. Both free and sulfoconjugated norepinephrine (NE) increased exercise-dependently. Moreover, heat loss in water caused elevation of plasma free NE. Free epinephrine (EPI) increases showed a highly significant correlation with NE except during fin swimming with a neoprene suit where EPI concentrations were constantly higher. ACTH and cortisol levels rose during exercise and paralleled those of plasma NE. Plasma aldosterone decreased in response to water immersion at rest. Blood volume regulating hormones such as plasma renin, aldosterone, and vasopressin were significantly higher during physical exercise. Moreover, increased pressure conditions during diving caused significantly higher secretion rates of all of these hormones, resulting in a higher systolic blood pressure. This clinical issue might be considered when examining diving ability. Lipolysis was elevated to the same degree after the three exercise schedules had been applied. As expected, plasma glucose also increased during physical activity. The lactate values observed after fin swimming, but not after diving with a breathing apparatus were closely related to NE. The lowest lactate levels were obtained during air-assisted diving.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenocorticotropic Hormone↗
PubMed1988

Sympathoadrenergic regulation in elite fencers in training and competition.

In ten fencers at the top national level the adrenergic regulation was investigated by determining the free and sulfoconjugated catecholamines (CA) in a training fight and a competition for the national championship to evaluate the influence of emotional strain in this discipline. In the training fight which is physically more strenuous, norepinephrine (NE) was significantly higher (+27%) than in the championship contest after which the epinephrine (EPI) level was more increased (+76.5%). Accordingly, the systolic blood pressure (SBP) was higher during competition and correlated with EPI. The share of the sulfated CA in their total amount was reduced in both loads. Since energy production in fencing is predominantly alactacitic during maximal loads of short duration and aerobic during submaximal load intensities, the lactate level in the training fight was below the anaerobic/aerobic threshold. The significantly higher lactate, glucose, and alanine levels during the fight for the national championship, presumably induced by the additional stimulation of the anaerobic muscular and hepatic glycogenolysis as well as muscular glycolysis, may be accounted to the fortified EPI secretion caused by emotional strain. The higher cortisol and renin levels may be explained by the strong central stimulation and the direct peripheral effect of EPI respectively.

Adult↗
PubMed1987

Sulfoconjugated catecholamines: lack of beta-adrenoceptor binding and adenylate cyclase stimulation in human mononuclear leukocytes.

The racemic 3-O-sulfates of epinephrine and norepinephrine as well as 4-O-sulfoconjugated dopamine were synthesized, highly purified and investigated with respect to their beta-adrenoceptor affinities and relative potencies in the receptor-coupled adenylate cyclase system in isolated human mononuclear leukocytes. The receptor affinities of all catecholamine sulfates were reduced at least 1,000-fold when compared to those of the free catecholamines. Furthermore, catecholamine sulfoconjugates did not produce intracellular cAMP signals. In contrast to the sulfated catecholamine metabolites, the 3-O-methylated catecholamines metanephrine and normetanephrine were found to behave as endogenous beta-adrenoceptor-competing agents with lower beta-receptor affinities than the corresponding free catecholamines. No beta-receptor agonist activity in the adenylate cyclase system was found with metanephrine and normetanephrine. Our data provide direct evidence that sulfoconjugation renders catecholamines inactive as beta-receptor ligands and must thus be regarded as a mechanism to control adrenergic action at the prereceptor level by a buffering of the concentration of free catecholamines. The physiological significance of a potential role of 3-O-methylated catecholamines as endogenous beta-receptor antagonists has to be further clarified.

Adenylyl Cyclases↗
PubMed1984

Identification of mechanisms involved in the modulation of release of noradrenaline in the hippocampus of the rabbit in vitro.

The modulation of the electrically-evoked release of noradrenaline by various possible neurotransmitters or neuromodulators in the hippocampus was studied in the dorsal part of the hippocampus of the rabbit. Slices of this tissue were preincubated with [3H]noradrenaline and superfused with a medium containing 30 microM cocaine. The evoked overflow of tritium was calcium-dependent, tetrodotoxin-sensitive and subject to modulation by presynaptic alpha 2-autoreceptors. Drugs with affinity for beta-adrenoceptors (up to 1 microM), muscarinic (up to 10 microM), nicotinic (up to 100 microM), GABA- (up to 1000 microM), glutamate- (up to 100 microM) and prostaglandin-receptors (up to 1 microM) did not show any modulatory influence on the evoked release of noradrenaline. In contrast, morphine (1 microM) and fentanyl (1 microM) significantly reduced the evoked overflow; this effect was antagonized by naloxone (10 microM), which, given alone, was ineffective. Apomorphine (1 microM) reduced the release of noradrenaline in the absence, and increased it in the presence, of 0.1 microM haloperidol; haloperidol (0.1 microM), given alone was ineffective. From these results it is concluded that, in addition to the well-known alpha 2-autoreceptor mechanism, presynaptic opiate-, D2- and probably D1-receptors might modulate the release of noradrenaline in the hippocampus.

Animals↗