Showing papers by "University of Mainz published in 1981"
TL;DR: While cyclosporin A did not interfere with the intracellular events required for the activation and subsequent clonal expansion of alloreactive T cells, the lack of interleukin 1 and interLEukin 2 induced by cyclospora A results in an inability of T responder cells to mount cytotoxic allograft responses in vitro.
Abstract: The site of action of the immunosuppressive drug cyclosporin A in in vitro cytotoxic allograft responses has been localized. General cytotoxic effects of the drug on proliferating T cells became apparent at concentrations of 500-1000 ng/ml, while selective effects were observed at concentrations of 10-100 ng/ml. The selective effects included a blockade of interleukin 2 release from activated T helper cells on the one hand and inhibition of interleukin 1 release from splenic adherent cells on the other. While cyclosporin A did not interfere with the intracellular events required for the activation and subsequent clonal expansion of alloreactive T cells, the lack of interleukin 1 and interleukin 2 induced by cyclosporin A results in an inability of T responder cells to mount cytotoxic allograft responses in vitro.
587 citations
01 Jan 1981
475 citations
TL;DR: The primary goal, to remove obstructing pelvic stones, was achieved in all cases and there were no untoward side effects, such as back pressure damage owing to flushing of the collecting system during ultrasound disintegration, or persistent infection.
339 citations
323 citations
TL;DR: In this paper, the Fourier transform of the solid-echo decay is compared with those from the free-induction decay in the slow-motion region where the motional correlation times are of the same order as the reciprocal anisotropic spin interactions.
260 citations
01 Sep 1981-Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology
TL;DR: In this article, it was observed that the blind Mexican Cave Fish repeatedly passes along objects new to it at a short distance, and experiments were conducted to support the hypothesis that water movements occurring between the stationary object and the fish as it passes by convey information about the location and shape of the object, which is detected by the lateral line organ of the fish.
Abstract: It was noticed that the blind Mexican Cave Fish repeatedly passes along objects new to it at a short distance. Observations and experiments are reported which support the hypothesis that water movements occurring between the stationary object and the fish as it passes by convey information about the location and possibly the shape of the object, which is detected by the lateral line organ of the fish. Water movements of the expected type were recorded with the help of a model fish equipped with a mechano-electric analogue of a free neuromast.
195 citations
TL;DR: Values in implantation tumors of rats are considerably lower than saturations in tumors of the oral cavity in humans as involved in this study, which can be explained by differences in growth stage, in the site of tumor growth, and in influences of the host on the tumor oxygenation.
Abstract: The oxygenation of cancer tissue in humans has been assessed by measuring the intracapillary oxyhemoglobin saturations (i.c.HbO 2 ) in solid tumors of the oral cavity using a cryophotometric micrometbod. From histological investigations the tumors can be classified into three qualities of vascularization: (i) well vascularized tumors, (ii) tumors with medium quality of vascularization, and (iii) poorly vascularized tumors. In all three tumor types i.c.HbO 2 distribution curves are shifted to significantly lower values than saturation curves in normal oral mucosa. The extent of this shift can be related to the degree of the reduction in tumor vasculature. In addition, great regional inhomogeneities in i.c.HbO 2 values can be detected. Comparison of these results with earlier measurements in the DS-Carcinosarcoma of the rat reveals that i.c.HbO 2 values in implantation tumors of rats are considerably lower than saturations in tumors of the oral cavity in humans as involved in this study. The differences in tumor oxygenation can be explained by differences in growth stage, in the site of tumor growth, and in influences of the host on the tumor oxygenation.
139 citations
TL;DR: Vascular invasion and spindle cells indicated a poor prognosis; the position of the tumour, oncocytic elements, calcification, lymphocytic infiltration or the predominance of clear cell or granular cells did not influence survival.
Abstract: Summary— Seventy-two patients with renal carcinoma (RC) in a solitary kidney or bilateral synchronous tumours underwent parenchyma-sparing excision of their neoplasms. This was performed in situin 51 and extracorporeally in 21 kidneys, with a complication rate respectively of 1 7 and 43%. The 5-year survival rates were 78% for unilateral disease, 48% for bilateral synchronous and 38% for bilateral asynchronous disease.
Survival correlated with Pcategory, grade and diameter of the tumour. Vascular invasion and spindle cells indicated a poor prognosis; the position of the tumour, oncocytic elements, calcification, lymphocytic infiltration or the predominance of clear cell or granular cells did not influence survival.
136 citations
TL;DR: In this paper, high-accuracy data for the ratio e-p to e-d scattering and a small normalization error for backward scattering data were obtained using a combination of high pressure gas target and liquid target systems.
135 citations
TL;DR: Harmane or other related β-carbolines are putative endogenous agonists of the benzodiazepine receptor, and the observation that diazepam is equally potent in inhibiting harmane- or picrotoxin-induced convulsions is supported, indicating a convulsive mechanism within the GABA receptor-benzodiazepines receptor system.
122 citations
01 Jan 1981
TL;DR: The sleep inducing potency of melatonin was tested in a double-blind study against placebo.
Abstract: The sleep inducing potency of melatonin was tested in a double-blind study against placebo. The application form was a nasal spray with a 0.85% solution of melatonin in ethanol. 70% of the subjects fell asleep after treatment with the hormone.
TL;DR: The data demonstrate that harmane affects not only the Benzodiazepine binding site but also other neuronal mechanisms, and the search for other β-carbolines with higher affinity for the benzodiazepines binding site as harmanE seems to be promising.
Abstract: β-Carbolines have been recently proposed as candidates for the unknown endogenous ligand of the benzodiazepine receptor. Out of the β-carboline derivatives already found in the mammalian CNS, harmane is clearly the most potent inhibitor of benzodiazepine receptor binding. Therefore, it has been considered as possible endogenous ligand for this new receptor system. However, a certain degree of specificity might be a basic condition to accept the hypothesis of harmane as the endogenous ligand. Thus, the effects of harmane as well as other β-carbolines on several neurotransmitter receptor binding systems in vitro and on some neuropharmacological tests in vivo were investigated. Harmane developed the highest affinity towards the benzodiazepine binding site among all systems investigated. Its IC50-values for inhibiting opiate and muscarinic cholinergic receptor binding were about four times lower than those for dopamine and serotonin receptor binding but were about four times higher than that found for the benzodiazepine receptor binding. Norharmane exerted a remarkable displacing activity only at the benzodiazepine binding site. Harmine affected mainly the opiate and cholinergic muscarinic system, whereas tetrahydronorharmane turned out to be a potent inhibitor of serotonin and dopamine receptor binding. Doses of harmane needed to produce convulsions as indication of its possible benzodiazepine receptor agonistic properties are also sufficient to diminish nociception and decrease body temperature whereas the apomorphine-induced licking rate was affected at higher doses. The data demonstrate that harmane affects not only the benzodiazepine binding site but also other neuronal mechanisms. Furthermore, only minor changes of the β-carboline structure lead to substantially different effects. Therefore, the search for other β-carbolines with higher affinity for the benzodiazepine binding site as harmane seems to be promising.
TL;DR: In this article, the numerical solution of the second kind Fredholm integral equation is discussed, where the functions f,g are given and continuous, and φα, 0<α≦m, is a given function on [0,∞] which satisfies the Euclidean norm.
Abstract: In this note we discuss the numerical solution of the second kind Fredholm integral equation:
$$ y(t) = f(t) + \lambda \int\limits_{\Omega } {{{\psi }_{\alpha }}(|t - s|)g(t,s)y(s)ds,\;t \in \bar{\Omega },} $$
(1)
Where \( \lambda \in ;
ot{ \subset }\backslash \{ 0\} \) , the functions f,g are given and continuous, |.| denotes the Euclidean norm, and φα, 0<α≦m, is a given function on [0,∞) which satisfies
$$ |\psi _{\alpha }^{{(j)}}(r)| \leqq {{C}_{j}}\left\{ {\begin{array}{*{20}{c}} {{{r}^{{a - m - j}}},j \geqq 0,m > \alpha > 0} \\ {\left\{ {\begin{array}{*{20}{c}} {\ln (r),} & {j = 0} \\ {{{r}^{{ - j}}}} & {j > 0} \\ \end{array} } \right\},\alpha = m} \\ \end{array} ,} \right. $$
with Cj not depending on r. Here Ω _ is the closure of a bounded domain Ω⊂ℝm.
01 Sep 1981-Journal of Comparative Physiology A-neuroethology Sensory Neural and Behavioral Physiology
TL;DR: In this article, blind Mexican cave fish were trained to discriminate between grids of vertical bars placed at various distances from each other, but this was possible only if the freely swimming fish was allowed to glide past the grids in close proximity.
Abstract: Blind Mexican cave fish were trained to discriminate between grids of vertical bars placed at various distances from each other. Discrimination was possible only if the freely swimming fish was allowed to glide past the grids in close proximity.
TL;DR: In this article, the spatial density distribution of Ba+ ions, confined in a rf quadrupole trap, has been measured by laser scanning across the trap, which allows to determine the ion temperature, assuming thermal equilibrium.
Abstract: The spatial density distribution of Ba+ ions, confined in a rf quadrupole trap, has been measured by laser scanning across the trap. This allows to determine the ion temperature, assuming thermal equilibrium. Under UHV conditions the average ion energy has been found to be one tenth of the trap potential well depth. Collisions with He at pressures up to 5×10−6 mbar reduce the ion temperature by a factor of 3.
TL;DR: The results show that the effects of quinidine and the different changes of the action potential configuration can be explained by an unspecific inhibition of the currents of sodium, calcium and potassium.
Abstract: The effects of quinidine on electrical and mechanical activity were investigated in atrial and/or ventricular heart muscle preparations from guinea pigs and cats. Quinidine (1--100 micrometer) exerted negative inotropic effects in papillary muscles from guinea pigs and cats. In guinea-pig left atria, a positive inotropic effect was superimposed on the negative inotropic effect in response to quinidine. Quinidine (100 micrometer) prolonged the duration of the action potential in guinea-pig atria but shortened it in guinea-pig ventricular muscle. In cat papillary muscles, the late repolarization was markedly prolonged by quinidine, but virtually no change of the plateau phase was observed. The maximal rate of rise and the resting potential were reduced by quinidine in all preparations. Voltage clamp experiments in cat ventricular muscle revealed that the calcium-dependent slow inward current and the outward current of potassium were decreased by quinidine. The effects of quinidine on slow inward current and force of contraction in ventricular muscle were antagonized by isoprenaline (1 micrometer). The results show that the effects of quinidine and the different changes of the action potential configuration can be explained by an unspecific inhibition of the currents of sodium, calcium and potassium. The negative inotropic effect of quinidine is probably related to the depressing effect of the drug on the calcium-dependent slow inward current. The positive inotropic effect of the drug in atrial heart muscle could be related to the prolongation of the action potential which may indirectly improve the influx of calcium during excitation.
TL;DR: It is concluded that the compound described by these authors, 7-N-(2-oxoethyl)guanine is in fact the major product of base alkylation in DNA after exposure to vinyl chloride.
TL;DR: In this paper, the principles of the synthesis of thermotropic liquid crystalline polymers, their structure dependant phase behaviour and their orientation in electric and magnetic fields are summarized, and an extended abstract of a paper presented at the conference on Liquid Crystalline Polymers in Leeds, 1980 is presented.
Abstract: The following is an extended abstract of a paper presented at the conference on Liquid Crystalline Polymers in Leeds, 1980, summarising the principles of the synthesis of thermotropic liquid crystalline polymers, their structure dependant phase behaviour and their orientation in electric and magnetic fields.
TL;DR: Archaean gneiss greenstone relationships are still unresolved in many ancient cratonic terrains although there is growing evidence that most of the late Archaean greenstone assemblages were deposited on older tonalitic crust as discussed by the authors.
Abstract: Archaean gneiss-greenstone relationships are still unresolved in many ancient cratonic terrains although there is growing evidence that most of the late Archaean greenstone assemblages were deposited on older tonalitic crust.
TL;DR: One of the prime roles of the thymus is to provide the microenvironment necessary for maturation and differentiation of prethymic T-precursor cells into mature T-cells, which are subsequently exported as post-thymi T-lymphocytes.
Abstract: The thymus represents the primary iymphoid organ producing (thymus derived) lymphocytes. Independent of antigenic stimulation, immunocompetent Tlymphocytes develop within this organ from prethymic precursor cells, which in turn are derived from hemopoetic stem cells. Thus, one ofthe prime roles ofthe thymus is to provide the microenvironment necessary for maturation and differentiation of prethymic T-precursor cells into mature T-cells, which are subsequently exported as post-thymic T-lymphocytes. In addition, production of one (or several) thytnic mediator(s), probably active at distinct sites, appears to be essential for maturation of immunocompetent T-cells (for review see Miller 1979). Not only the thymus, but also gene products of the MHC exert a profound influence on T-cell reactivity. It has been shown that the frequency of alloreactive T-lymphocytes is at least 100 times as high as the frequency of cells reacting to foreign antigens (Simonson 1967, Fischer-Lindahl & Wilson 1977, MacDonald et al. 1980). To account for this high frequency, Jerne (1971) originally proposed that the repertoire of T-cells depends on a set of germ-line vgenes which code for structures essentially complementary to the MHC-alleles of that species. In the thymus, the T-cell precursors that are specific for selfMHC gene products are first selected by self-MHC-antigens encountered on thymic epithehal cells and allowed to differentiate and to proliferate. In a second
TL;DR: In this paper, solid echo technique is applied to determining residual dipolar and quadrupolar couplings in molten polyethylene (PE) and deuterated PE, respectively, and the residual coupling defined by the square root of the second moment is about 1% of the corresponding quantity in the solid.
Abstract: The solid echo technique is applied to determining residual dipolar and quadrupolar couplings in molten polyethylene (PE) and deuterated PE, respectively. The residual coupling defined by the square root of the second moment is about 1% of the corresponding quantity in the solid. It increases with molecular weight, and decreases with rising temperature. A theoretical treatment of time dependent residual couplings yields a decay time that is found experimentally to be about 0.1 ms in molten PE, and independent of molecular weight and temperature within our limits of accuracy. The residual coupling is discussed in relation with chain entanglement in PE. Measurements of the spin-lattice and spin-spin relaxation time are related with the more rapid segmental motion of PE chains.
TL;DR: In this article, a simple method for computing magnetic resonance line shapes by superposition of a relatively small number of subspectra, which can in turn be calculated analytically, is described.
TL;DR: The analysis of the prophylactically treated cases showed that the dosage of 25 μg l-Thyroxine and 5 μg Tri-iodothyronine in critically ill infants was rarely sufficient to produce normal serum thyroxine levels and it seems advisable to double the dose of thyroid hormone during the acute stage of the disease.
Abstract: Our previous examinations had shown that 9 of 13 premature infants with severe respiratory distress had hypothyroid T4-values. On the basis of these results a prospective study was initiated. Every second neonate born after less than 37 weeks gestation or weighing less than 2200 g and admitted to our intensive care unit since Janary 1979 received a prophylactic dose of 25 μg l-Thyroxine and 5 μg Tri-iodothyronine daily. Five of the patients inadvertently did not receive the drug and were included in the non-treated group which thus numbered 55. Both groups were nearly identical with regard to gestational age, birth weight and Apgar score. In the treated group of 45 infants three (=6.6%) died. In the untreated group of 55 infants 16 (=29%) died. The probability that the different mortality in the two groups was due to chance alone is less than 0.5% (χ2-test: P<0.005). In 14 of the 55 non-treated patients transient hypothyroidism developed. Five patients with transient hypothyroidism and 2 patients with low T4-values without a TSH-increase were treated with thyroid hormone after ascertainment of their serum thyroxine levels and six survived. The analysis of the prophylactically treated cases showed that the dosage of 25 μg l-Thyroxine and 5 μg Tri-iodothyronine in critically ill infants (i.e., those who were mechanically ventilated or had sepsis) was rarely sufficient to produce normal serum thyroxine levels. In these children thyroxine usually rose to normal levels only when they had passed the acute stage of the disease. It therefore seems advisable to double the dose of thyroid hormone during the acute stage of the disease.
TL;DR: In a comparative morphological study it is shown that different particular microenvironmental conditions determine the growth and/or survival of different cell types of dissociated brain cells.
TL;DR: In this paper, the γ-rays following the β − decay of 224,226 Fr have been investigated by means of multispectrum analysis and γγ coincidence measurements using Ge(Li) spectrometers.
TL;DR: In this article, the relationship between drawing rate and drawing stress was studied for amorphous poly(ethylene terephthalate) (PET) under various experimental conditions, and three types of expriments were performed: simple drawing with necking at constant rate, drawing through a conical die, and drawing at constant stress.
Abstract: The relationship between drawing rate and drawing stress was studied for amorphous poly(ethylene terephthalate) (PET) under various experimental conditions. Three types of expriments were performed: simple drawing with necking at constant rate, drawing through a conical die, and drawing at constant stress. Under constant stress conditions a transition between two stable regimes of drawing can be observed. The transition occurs at a critical stress σc at which the rate of neck propagation changes by some orders of magnitude. Such a transition was found both below and above the glass transition of PET. With constant drawing rates instabilities of neck propagation were observed under certain experimental conditions. Such self-oscillations, described by other authors, are not due to heat effects as has been proposed, but are related to the existence of the critical stres σc.
Stress-induced transitions in deformation behavior as in PET were observed for polypropylene and nylon 6 but not for polycarbonate. The results obtained by various methods including morphological studies do not support the assumption that the instabilities are caused by thermal effects due to the dissipation of deformation energy. Rather, a model is proposed which is based on the existence of a “spinodal transition” from the isotropic into the highly oriented state.
TL;DR: In this paper, the properties of a side chain polymer exhibiting a liquid crystalline phase in addition to a partially crystalline state and the isotropic fluid state were investigated, and the kinetics of phase transitions between these states were analyzed.
Abstract: The structures, textures as well as thermodynamic properties of a side chain polymer exhibiting a liquid crystalline phase in addition to a partially crystalline state and the isotropic fluid state were investigated. Furthermore the kinetics of phase transitions between these states were analyzed. It was found that the properties of this polymer are intermediate between that of low molecular weight liquid crystals and common polymers. In particular it was observed that the relation between the liquid crystalline texture and the structure is different from that of low molecular weight liquid crystals and that the properties of the crystalline and liquid crystalline state depend strongly on the tacticity of the polymer.
TL;DR: The pharmacokinetics of atenolol were determined following acute intravenous and chronic oral administration to 20 subjects with a glomerular filtration rate between 5 and 113 ml/min and Plasma levels in a further 5 patients on haemodialysis were measured after intravenous treatment.
Abstract: The plasma levels and urinary excretion of carteolol and its main metabolites 8-hydroxycarteolol and carteolol glucuronide were investigated in 6 healthy subjects and 9 patients with varying degrees of renal impairment following a single oral dose of 30 mg carteolol hydrochloride. In healthy subjects the half-life of carteolol was 7.1 h. 63% of the administered dose was recovered unchanged in urine, and in all 84% was excreted by the kidneys. The renal clearance of carteolol was 255 ml/min. In chronic renal failure (CRF) the terminal half-life was increased to a maximum of 41 h. Both the elimination rate constant and renal clearance were closely related to the creatinine clearance. In CRF the recovery of carteolol and its metabolites from urine was considerably reduced, suggesting that another pathway of drug elimination becomes relevant in renal disease. To avoid an increase in side-effects due to drug accumulation, the dosage of carteolol should be adjusted in relation to the reduction in creatinine clearance. The maintenance dose should be reduced to a half in patients with a creatinine clearance below 40 ml/min and above 10 ml/min. In those with a creatinine clearance of 10 ml/min or less, the dose should be reduced to 1/4.
TL;DR: The results provide conclusive evidence that severe arterial hypocapnia leads to an insufficient O2 supply of the brain cortex, which in turn seems to counteract the influence of hypocAPnia on cortical blood flow regulation.
Abstract: The effect of a stepwise decrease in PaCO2 from 3.9-1.6 kPa on rCBF, rCMRO2, tissue PO2 and concentrations of glucose, lactate, pyruvate, ATP, ADP, AMP and phosphocreatine in the brain cortex was studied in cats lightly anaesthetized with sodium pentobarbital. 1. Moderate lowering of PaCO2 to 2.5 kPa induced in all animals a homogeneous decrease of rCBF in corresponding areas of the right and left hemisphere. Mean rCBF fell from 129.2 to 103.1 ml X 100 g-1 X min-1, while rCMRO2 remained unchanged (12.7-12.9 ml X 100 g-1 X min-1). The tissue PO2 frequency histograms showed a shift to lower values without indicating the presence of brain tissue hypoxia. 2. Severe arterial hypocapnia (PaCO2 = 1.6 kPa) caused an inhomogeneous blood flow reaction. Both further decreased as well as increased rCBF values were measured simultaneously in the brain cortex of individual animals (mean rCBF = 97.6 ml X 100 g-1 X min-1). At the same time tissue PO2 measurements and metabolite assays indicated the presence of pronounced brain tissue hypoxia. The tissue concentrations of lactate and pyruvate and the lactate/pyruvate ratio were significantly increased, while the phosphocreatine concentration was significantly reduced. In addition, rCMRO2 decreased to 11.3 ml X 100 g-1 X min-1. The results provide conclusive evidence that severe arterial hypocapnia leads to an insufficient O2 supply of the brain cortex, which in turn seems to counteract the influence of hypocapnia on cortical blood flow regulation.