A sensitive and robust method for automated on-line monitoring of enzymatic activities in water and water resources

The realisation of a novel concept for automated on-line monitoring of enzymatic activities in water was successfully demonstrated by long-term field testing at two remote Austrian ground water resources. The β-D-glucuronidase (GLUC) activity was selected as a representative enzymatic model parameter for the on-line determination. But the device can be adapted for any enzymatic reaction with diagnostic relevance for microbial water quality monitoring, as demonstrated for the β-D-galactosidase activity. Automated filtration of volumes up to 5 litres supports sensitive quantification of enzymatic activities. Internet-based data transfer, using internal control parameters for verification and a dynamic determination of the limit of quantification, enabled robust enzymatic on-line monitoring during a 2-year period. A proportion of 5,313 out of 5,506 GLUC activity measurements (96.5%) could be positively verified. Hydrological (discharge, gauge, turbidity, temperature, pH, electric conductivity, spectral absorbance coefficient at 254 nm) as well as microbiological parameters (Escherichia coli, coliforms) were concurrently determined to characterise the investigated ground water resources. The enzymatic on-line measurements closely reflected the different hydrological conditions and contamination patterns of the test sites. Contrary to expectations, GLUC did not qualify as a proxy-parameter for the occurrence of cultivation-based E. coli contamination and warrants further detailed investigations on its indication capacity as a rapid means for microbial faecal pollution detection in such aquatic habitats. Microbial on-line monitoring is likely to become more important in the future, complementing existing surveillance strategies for water safety management. Further perspectives on the application of such analytical on-line technologies, such as their connection with event-triggered sampling and standardised diagnostics, are discussed.

Hypothesis-driven approach for the identification of fecal pollution sources in water resources

Water resource management must strive to link catchment information with water quality monitoring. The present study attempted this for the field of microbial fecal source tracking (MST). A fecal pollution source profile based on catchment data (e.g., prevalence of fecal sources) was used to formulate a hypothesis about the dominant sources of pollution in an Austrian mountainous karst spring catchment. This allowed a statistical definition of methodical requirements necessary for an informed choice of MST methods. The hypothesis was tested in a 17-month investigation of spring water quality. The study followed a nested sampling design in order to cover the hydrological and pollution dynamics of the spring and to assess effects such as differential persistence between parameters. Genetic markers for the potential fecal sources as well as microbiological, hydrological, and chemo-physical parameters were measured. The hypothesis that ruminant animals were the dominant sources of fecal pollution in the catchment was clearly confirmed. It was also shown that the concentration of ruminant markers in feces was equally distributed in different ruminant source groups. The developed approach provides a tool for careful decision-making in MST study design and might be applied on various types of catchments and pollution situations.

The spectral absorption coefficient at 254 nm as a real-time early warning proxy for detecting faecal pollution events at alpine karst water resources

Because spring water quality from alpine karst aquifers can change very rapidly during event situations, water abstraction management has to be performed in near real-time. Four summer events (2005-2008) at alpine karst springs were investigated in detail in order to evaluate the spectral absorption coefficient at 254 nm (SAC254) as a real-time early warning proxy for faecal pollution. For the investigation Low-Earth-Orbit (LEO) Satellite-based data communication between portable hydrometeorological measuring stations and an automated microbiological sampling device was used. The method for event triggered microbial sampling and analyzing was already established and described in a previous paper. Data analysis including on-line event characterisation (i.e. precipitation, discharge, turbidity, SAC254) and comprehensive E. coli determination (n>800) indicated that SAC254 is a useful early warning proxy. Irrespective of the studied event situations SAC254 always increased 3 to 6 hours earlier than the onset of faecal pollution, featuring different correlation phases. Furthermore, it seems also possible to use SAC254 as a real-time proxy parameter for estimating the extent of faecal pollution after establishing specific spring and event-type calibrations that take into consideration the variability of the occurrence and the transferability of faecal material It should be highlighted that diffuse faecal pollution from wildlife and live stock sources was responsible for spring water contamination at the investigated catchments. In this respect, the SAC254 can also provide useful information to support microbial source tracking efforts where different situations of infiltration have to be investigated.

Impaired cardiac autonomic control relates to disease severity in pulmonary hypertension

Pulmonary arterial hypertension (PAH) results in chronic right heart failure, which is associated with an increase in sympathetic tone. This may adversely affect cardiac autonomic control. We investigated the changes in cardiac autonomic nervous activity in relation to disease severity in patients with PAH. In 48 patients with PAH (median World Health Organization class III, pulmonary artery pressure 52+/-14 mmHg, pulmonary vascular resistance 1,202+/-718 dyn x s x cm(-5), cardiac index 2.0+/-0.8 L x min(-1) x m(-2)) and 41 controls, cardiac autonomic nervous activity was evaluated by measurement of heart rate variability (HRV) and baroreflex sensitivity. All patients underwent cardiopulmonary exercise testing (peak oxygen uptake 13.2+/-5.1 mL x kg(-1) x min(-1), minute ventilation/carbon dioxide production slope 47+/-16). In patients with PAH, spectral power of HRV was reduced in the high-frequency (239+/-64 versus 563+/-167 ms2), low-frequency (245+/-58 versus 599+/-219 ms2) and very low-frequency bands (510+/-149 versus 1106+/-598 ms2; all p<0.05). Baroreflex sensitivity was also blunted (5.8+/-0.6 versus 13.9+/-1.2 ms x mmHg(-1); p<0.01). The reduction in high-frequency (r = 0.3, p = 0.04) and low-frequency (r = 0.33, p = 0.02) spectral power and baroreflex sensitivity (r = 0.46, p<0.01) was related to the reduction in peak oxygen uptake. Patients with PAH have a marked alteration in cardiac autonomic control that is related to exercise capacity and may, therefore, serve as an additional marker of disease severity.

Added value of online satellite data transmission for flood forecasting: warning systems in medium-size catchments

The present paper deals with the implementation of online data transferred via LEO satellite communication in a flood forecasting system. Although the project is ongoing, it is already recognised that the information chain: "measurement-transmission-forecast-alert" can be shortened, i.e., the flood danger can be more rapidly communicated to the population at risk. This gain is particularly valuable for medium size catchments where the concentration time (basin time of response to rainfall) is short.

Quantitative microbial faecal source tracking with sampling guided by hydrological catchment dynamics

The impairment of water quality by faecal pollution is a global public health concern. Microbial source tracking methods help to identify faecal sources but the few recent quantitative microbial source tracking applications disregarded catchment hydrology and pollution dynamics. This quantitative microbial source tracking study, conducted in a large karstic spring catchment potentially influenced by humans and ruminant animals, was based on a tiered sampling approach: a 31-month water quality monitoring (Monitoring) covering seasonal hydrological dynamics and an investigation of flood events (Events) as periods of the strongest pollution. The detection of a ruminant-specific and a human-specific faecal Bacteroidetes marker by quantitative real-time PCR was complemented by standard microbiological and on-line hydrological parameters. Both quantitative microbial source tracking markers were detected in spring water during Monitoring and Events, with preponderance of the ruminant-specific marker. Applying multiparametric analysis of all data allowed linking the ruminant-specific marker to general faecal pollution indicators, especially during Events. Up to 80% of the variation of faecal indicator levels during Events could be explained by ruminant-specific marker levels proving the dominance of ruminant faecal sources in the catchment. Furthermore, soil was ruled out as a source of quantitative microbial source tracking markers. This study demonstrates the applicability of quantitative microbial source tracking methods and highlights the prerequisite of considering hydrological catchment dynamics in source tracking study design.

Microbiological monitoring and automated event sampling at karst springs using LEO-satellites

Data communication via Low-Earth-Orbit (LEO) Satellites between portable hydrometeorological measuring stations is the backbone of our system. This networking allows automated event sampling with short time increments also for E. coli field analysis. All activities of the course of the event-sampling can be observed on an internet platform based on a Linux-Server. Conventionally taken samples compared with the auto-sampling procedure revealed corresponding results and were in agreement with the ISO 9308-1 reference method. E. coli concentrations were individually corrected by event specific inactivation coefficients (0.10-0.14 day(-1)), compensating losses due to sample storage at spring temperature in the auto sampler.Two large summer events in 2005/2006 at an important alpine karst spring (LKAS2) were monitored including detailed analysis of E. coli dynamics (n = 271) together with comprehensive hydrological characterisations. High-resolution time series demonstrated a sudden increase of E. coli concentrations in spring water (approximately 2 log10 units) with a specific time delay after the beginning of the event. Statistical analysis suggested the spectral absorption coefficient measured at 254 nm (SAC254) as an early warning surrogate for real time monitoring of faecal input. Together with the LEO-satellite based system it is a helpful tool for early-warning systems in the field of drinking water protection.

The role of 5ht2c receptors in affective disorders

5-HT(2C) receptors are predominantly localised in the brain and their dysregulation may contribute to particular symptoms of anxiety and depression. The marked affinity of several clinically established psychotropic agents sites (e.g., tricyclic antidepressants, clozapine, fluoxetine) for 5-HT(2C) receptor has generated interest in the therapeutic potential of selective, high affinity 5-HT(2C) receptor ligands. Like the selective serotonin re-uptake inhibitor (SSRI) fluoxetine, high affinity selective agonists such as Ro 60-0175 and Ro 60-0332 have potent in vivo activity in animal models suggestive of therapeutic action against depression, obsessive-compulsive disorder (OCD) and panic disorders. In contrast, 5-HT(2C) receptor antagonists such as SB-200646A or SB-221284 show signs of anxiolytic-like activity in tests for conditioned and phobic-like anxiety in rodents whereas they are inactive in tests indicative of antidepressant, antiOCD and antipanic activity. These results are consistent with an important hypothesis proposing that 5-HT has a complex, dual action on the neural mechanism of anxiety by either facilitating or inhibiting different kinds of anxiety in different brain regions. They also suggest that 5-HT(2C) receptor subtypes play an important role in the therapeutic properties of SSRIs. Certain 5-HT(2C) receptor antagonists may possess negative efficacy at 5-HT(2C) receptors and, as inverse agonists, may control constitutive receptor activity possibly characterising some psychopathological states. Receptor variants exist in the human population and indicate possible associations between somatic mutations in the 5-HT(2C) receptor and psychopathology or response to drug treatment. Selective 5-HT(2C) receptor ligands may offer innovative and improved therapeutic opportunities for the biological treatment of specific aspects of psychiatric syndromes.

Remote water quality monitoring "on-line" using LEO satellites

Low Earth Orbit Satellites (LEOS) provide world-wide "nomadic" data-communication using low-cost and low-power "cellular like" equipment. LEOS allow us to also exploit those regions, which up to now were inaccessible by land-based wireless or geostationary (GEO) satellite systems. First, this paper compares satellite systems and summarizes features of the ORBCOMM LEO-system used. In the main part, a detailed report is given on a hydrogeological prototype implementation for remote water-quality monitoring: setup, obtained results, conclusions and further aspects as well as cost comparisons. As a result, LEO satellite data transmission may be a reliable low-cost alternative even to GSM-SMS for low data volume applications.

Protein adsorption on surfaces: dynamic contact-angle (DCA) and quartz-crystal microbalance (QCM) measurements

Adsorption of the protein bovine serum albumin (BSA) on gold has been tested at various concentrations in aqueous solution by dynamic contact-angle analysis (DCA) and quartz-crystal microbalance (QCM) measurements. With the Wilhelmy plate technique advancing and receding contact angles and the corresponding hysteresis were measured and correlated with the hydrophilicity and the homogeneity of the surface. With electrical admittance measurements of a gold-coated piezoelectrical quartz crystal, layer mass and viscoelastic contributions to the resonator's frequency shift during adsorption could be separated. A correlation was found between the adsorbed mass and the homogeneity and hydrophilicity of the adsorbed film.

Identification of essential residues involved in the glutamate binding pocket of the group II metabotropic glutamate receptor

Metabotropic glutamate (mGlu) receptors are a family of G-protein-coupled receptors that play central roles as modulators of both glutamatergic and other major neurotransmitter systems in CNS. Using molecular modeling, site-directed mutagenesis, [(3)H]LY354740 binding, [(35)S]GTPgammaS binding, and activation of GIRK current, we have been able to identify residues crucial for the binding of LY354740 and glutamate to rat mGlu2 receptors. Several of the crucial residues located in the binding site (Arg-57, Tyr-144, Tyr-216, Asp-295) have not been identified previously. We propose that the gamma-carboxyl group of LY354740 forms H-bonds to Arg-57, whereas the alpha-carboxyl group forms an H-bond with the hydroxyl group of Ser-145. The alpha-amino group of LY354740 forms H-bonds to Asp-295 and to the side-chain hydroxyl group of Thr-168. In addition, Tyr-144 may establish a hydrophobic (C-H/pi)-interaction with the bicyclo-hexane ring of LY354740. Furthermore, the mutation of residues Ser-148 and Arg-183, which are too remote for a direct interaction, affected the ligand affinity dramatically. These results suggest that Ser-148 and Arg-183 may be important for the 3D structure and/or are involved in closure of the domain. Finally, Asp-146, which is also remote from the binding site, was shown to be involved in the differential binding affinity of [(3)H]LY354740 for mGlu2 versus mGlu3 receptors. All the mGlu receptors except mGlu2 are activated by Ca(2+) and have serine instead of aspartic acid at this position, which suggests a critical role of this aspartic acid residue in the binding properties of this unique receptor.

Piperidine renin inhibitors: from leads to drug candidates

Non-peptidomimetic renin inhibitors of the piperidine type represent a novel structural class of compounds potentially free of the drawbacks seen with peptidomimetic compounds so far. Synthetic optimization in two structural series focusing on improvement of potency, as well as on physicochemical properties and metabolic stability, has led to the identification of two candidate compounds 14 and 23. Both display potent and long-lasting blood pressure lowering effects in conscious sodium-depleted marmoset monkeys and double transgenic rats harboring both the human angiotensinogen and the human renin genes. In addition, 14 normalizes albuminuria and kidney tissue damage in these rats when given over a period of 4 weeks. These data suggest that treatment of chronic renal failure patients with a renin inhibitor might result in a significant improvement of the disease status.

5-HT(6) receptor antagonists: lead optimisation and biological evaluation of N-aryl and N-heteroaryl 4-amino-benzene sulfonamides

RO-04-6790 (6a) has been identified in a random screen for 5-HT(6) receptor antagonists. In a medicinal chemistry optimisation program a series of analogs comprising N-heteroaryl- and N-arylbenzenesulfonamides have been synthesised and investigated for their binding affinity. Compounds with a logD profile indicative of brain penetration have been subjected to in vivo testing for reversal of a scopolamine-induced retention deficit in a passive avoidance paradigm.

Characterization of [(3)H]-LY354740 binding to rat mGlu2 and mGlu3 receptors expressed in CHO cells using semliki forest virus vectors

The binding properties of [(3)H]-LY354740 were characterized on rat metabotropic glutamate receptors mGlu2 and mGlu3 expressed in Chinese hamster ovary (CHO) cells using Semliki Forest virus vectors. The saturation isotherm gave K(D) values of 20+/-5 and 53+/-8 nM and B(max) values of 474+/-161 and 667+/-89 fmol/mg protein for mGlu2 and mGlu3 receptors, respectively. NMDA, CaCl(2), DHPG and kainate were inactive up to 1 mM, whereas LY341495, DCG IV and ibotenate inhibited [(3)H]-LY354740 binding with similar potencies on both receptors. L-CCG I, L-AP4, L-AP5, LY354740 and 1S,3R-ACPD were 2- to 4-fold more potent inhibitors of [(3)H]-LY354740 binding to mGlu2 than mGlu3 receptors. However, MPPG and L-AP3 had a 6-fold and DTT a 28-fold preference for mGlu2 over mGlu3. ZnCl(2), at 10 mM, inhibited more than 70% of [(3)H]-LY354740 binding to mGlu2 receptors. At the same concentration it did not affect significantly [(3)H]-LY354740 binding to mGlu3 receptors. On the contrary, glutamate, quisqualate, EGLU and NAAG showed a 3-, 5-, 7- and 12-fold preference for mGlu3 over mGlu2. Finally, GTPgammaS, which partially inhibited the binding on mGlu2 receptors, was inactive to inhibit [(3)H]-LY354740 binding on mGlu3 receptors.

Thickness shear mode resonators ("mass-sensitive devices") in bioanalysis

A short overview of function and experimental set-ups of acoustic wave devices is given which, in contrast to other bioanalysis techniques, are based on a mechanical transduction mechanism. The most frequently used device is the thickness shear mode resonator (TSMR), which in the last few years was intensively employed in biosensor applications. TSMR biosensor studies in the field of nucleic acid interaction, adsorption of proteins to surfaces and immunosensing are reviewed. A main point concerns the interpretation of the sensor response not only in terms of mass loading, which underestimates the capabilities of these devices.

Synthesis of heterocyclic enol ethers and their use as group 2 metabotropic glutamate receptor antagonists

Heterocyclic enol ethers of type 1 were studied with respect to the inhibition of 1S,3R-ACPD (10 microM)-stimulated GTP gamma35S binding on rat mGluR2 transfected cell membranes. The structure activity relationship with regard to the substitution pattern of the phenyl ring, the oxygen substituent and the nature of the heterocycle is discussed.

Piperidine-renin inhibitors compounds with improved physicochemical properties

Piperidine renin inhibitors with heterocyclic core modifications or hydrophilic attachments show improved physical properties (lower lipophilicity, improved solubility). Tetrahydroquinoline derivative rac-30 with a molecular weight of 517 and a log D(pH 7.4) of 1.9 displays potent and long lasting blood pressure lowering effects after oral administration to sodium depleted conscious marmosets.

Substituted piperidines--highly potent renin inhibitors due to induced fit adaptation of the active site

The identification, synthesis and activity of a novel class of piperidine renin inhibitors is presented. The most active compounds show activities in the picomolar range and are among the most potent renin inhibitors ever identified.

Renin inhibition by substituted piperidines: a novel paradigm for the inhibition of monomeric aspartic proteinases?

BACKGROUND

The aspartic proteinase renin catalyses the first and rate-limiting step in the conversion of angiotensinogen to the hormone angiotensin II, and therefore plays an important physiological role in the regulation of blood pressure. Numerous potent peptidomimetic inhibitors of this important drug target have been developed, but none of these compounds have progressed past clinical phase II trials. Limited oral bioavailability or excessive production costs have prevented these inhibitors from becoming new antihypertensive drugs. We were interested in developing new nonpeptidomimetic renin inhibitors.

RESULTS

High-throughput screening of the Roche compound library identified a simple 3, 4-disubstituted piperidine lead compound. We determined the crystal structures of recombinant human renin complexed with two representatives of this new class. Binding of these substituted piperidine derivatives is accompanied by major induced-fit adaptations around the enzyme's active site.

CONCLUSIONS

The efficient optimisation of the piperidine inhibitors was facilitated by structural analysis of the renin active site in two renin-inhibitor complexes (some of the piperidine derivatives have picomolar affinities for renin). These structural changes provide the basis for a novel paradigm for inhibition of monomeric aspartic proteinases.

In vitro binding characteristics of a new selective group II metabotropic glutamate receptor radioligand, [3H]LY354740, in rat brain

The in vitro binding of [3H]LY354740, the first high affinity group II-selective metabotropic glutamate (mGlu) receptor radioligand, was characterized in rat cortical, hippocampal, and thalamic membranes as well as in rat brain sections. [3H]LY354740 binding was saturable in all regions investigated. Nonspecific binding (in the presence of 10 microM DCG-IV) was approximately 8% of the total. Ionotropic glutamate receptor agonists, N-methyl-D-aspartate, (R,S)-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid/kainate, a Na+-dependent glutamate uptake blocker as well as a group I-selective mGlu receptor agonist (all up to 1 mM) did not inhibit [3H]LY354740 binding to cortical membranes. However, several known metabotropic receptor ligands inhibited the binding with the following rank order of potency: LY354740 = LY341495 > (2S,2'R, 3'R)-2-(2',3'-dicarboxycyclopropyl)glycine = (2S,1'S, 2'S)-2-(2-carboxycyclopropyl)glycine > glutamate = (1S, 3R)-1-aminocyclopentane-1,3-dicarboxylic acid > (2S,1'S, 2'S)-2-methyl-2-(2-carboxycyclopropyl)-glycine > quisqualate > ibotenate > L-2-amino-3-phosphonopropionic acid = (S)-alpha-methyl-4-carboxyphenylglycine > L-(+)-2-amino-4-phosphonobutyric acid. N-Acetyl-aspartyl-glutamate, (2S)-alpha-ethylglutamic acid, and (R, S)-alpha-methyl-4-phosphonophenylglycine inhibited [3H]LY354740 binding in a biphasic manner. Guanosine-5'-O-(3-thiotriphosphate concentration-dependently and almost completely inhibited the binding. Finally, in parasagittal sections of rat brain, a high density of specific binding was observed in the accessory olfactory bulb, cortical regions (layers 1-3 > 4-6), caudate putamen, molecular layers of the hippocampus and dentate gyrus, presubiculum, retrosplenial cortex, anteroventral thalamic nuclei, and cerebellar granular layer, reflecting its preferential (perhaps not exclusive) affinity for presynaptic and postsynaptic mGlu2 receptors. Thus, the pharmacology, tissue distribution, and sensitivity to guanosine-5'-O-(3-thiotriphosphate show that [3H]LY354740 binding probably occurs to group II mGlu receptors in rat brain.

In vitro and in vivo effects of tetrakisphosphonates on bone resorption, tumor osteolysis, ectopic calcification, and macrophages

The biological effects of bisphosphonates in calcium-related disorders are attributed to the incorporation of the bisphosphonates in bone, enabling direct interaction with osteoclasts and/or osteoblasts. The high accumulation of bisphosphonates in bone, due to their high affinity to hydroxyapatite (HAP), is essential for mediating in vitro and in vivo activity. In this study we examined the activity of tetrakisphosphonates, molecules containing two P-C-P type bisphosphonate moieties connected by a carbon chain. The novel compounds were examined in a battery of in vitro and in vivo models including HAP formation and dissolution, ectopic calcification, bone resorption, tumor osteolysis, and of macrophage-like cells (anti- or pro-inflammatory properties). The inhibition of ectopic calcification was ranked as follows: geminal bisphosphonates > bisacylphosphonates > tetrakisphosphonates. Pamidronate, but not the tetrakisphosphonates, was an effective antiosteolytic agent. Neither DNTP (tetrasodium 1,9-dihydroxynonane 1,1,9,9-tetrakisphosphonate) nor the bisacylphosphonate, PiBP (pimeloylbisphosphonate) seem to possess strong macrophage suppressive or inductive effects and can be considered to be relatively inactive in terms of anti- or pro-inflammatory action. A significant anticalcification effect was caused by various phosphonates, such as the tetrakisphosphonates, but DNTP, a tetrakisphosphonate, was found toxic as it impeded somatic growth and bone development.

[Pedagogic responsibilities in rehabilitation of brain damaged patients]

In contrast to medical science, education has so far undertaken but little analysis of its tasks in neurological rehabilitation, although these are manifold and essential in achieving successful outcomes. While specific remedial services have been made available to persons with congenital brain damage in the schools for the mentally retarded, a need to catch up in this respect is obvious for persons with acquired brain damage. Extension of the network of neurological rehabilitation facilities has engendered a challenge to (special) education, which now is in the process of developing neuroeducational concepts for therapy and instruction. Starting out from a didactical analysis to identify the conditional and determinative fields involved, the foundations of educational action are set forth, to wit: the theories of intelligence and its development, as well as the concept positing a hierarchy of learning modes. The various modes or types of learning are outlined and illustrated by examples. Further dealt with are prerequisites for specific learning modes to take effect, as well as neurological relationships; the need for cooperating in an interdisciplinary team is substantiated. Starting out from the premise of their fundamental ability to learn, the article then discusses the teaching-learning processes for persons with neurological disablement, with attention paid to both memory, personality dimensions as well as classroom instruction, and the relationship among perception, learning and instruction. Concluding, the author posits participation of persons with brain damage in the process of determining their rehabilitative goals, as well as empathy on the part of the professionals involved with them in therapy, classroom and training.

[School--and then what? On the occupational integration of severely handicapped adolescents--attempt at defining the current status]

The life situation of young people faced with severe consequences of their physical disablement is deteriorating due to general economic and worklife developments. Their right to occupational qualification is by no means universally honoured, and even those who have undergone vocational training find it increasingly hard to secure a job. This contribution therefore considers overall societal and economic conditions as well as trends forecast, discussing traditional and current views of successful life coping with or without remunerative work. Particular interest is taken in how disabled people themselves see their position in the working society. Problems of transition from school to post-school life settings are pointed out.

Ciprokiren (Ro 44-9375). A renin inhibitor with increasing effects on chronic treatment

The present study characterizes the new transition-state renin inhibitor ciprokiren (Ro 44-9375) in squirrel monkeys. Arterial blood pressure was monitored by telemetry in freely moving, chronically instrumented conscious animals. In vitro at pH 7.4, ciprokiren inhibited human renin in buffer and human plasma with an IC50 of 0.07 and 0.65 nmol/L, respectively. It was equipotent against primate plasma renin and also inhibited plasma renin from dog and guinea pig in the nanomolar range (IC50, 29 and 65 nmol/L, respectively). After acute oral administration it reduced arterial blood pressure dose dependently in normotensive sodium-depleted and cyclosporin-induced hypertensive squirrel monkeys, starting with the minimal oral dose of 3 micrograms/kg. Daily oral doses of 1 microgram/kg showed a progressive blood pressure decrease, with a maximal response reached after 1 week. The drug could also be applied transdermally with similar hemodynamic effects without any decrease of plasma renin activity or plasma immunoreactive angiotensin II. Thus, ciprokiren is characterized in squirrel monkeys as a renin inhibitor with high in vivo potency that might act mainly in the tissular compartment.

Large scale preparation of chiral building blocks for the P3 site of renin inhibitors

Racemic ethyl 2-benzyl-3-(tert-butylsulfonyl)propionate (1) and racemic ethyl 2-benzyl-3-[[1-methyl-1-((morpholin-4-yl)carbonyl)ethyl]sulfonyl] propionate (3) were enantioselectively hydrolyzed by subtilisin Carlsberg generating the respective (S)-acids used as building blocks for renin inhibitors. The esters were readily converted as emulsions at elevated temperature, in a suspended form or a two-phase-liquid system. The enzyme maintained its excellent selectivity and a good activity also at high initial substrate concentrations (up to 50% w/w). The enzymatic reaction and work-up were optimized and scaled up. Emulsion problems during work-up encountered with these highly concentrated mixtures were solved by application of a disk separator for phase separation.

[Ethical principles in rehabilitation]

Set out and discussed are fundamental social-ethical issues in rehabilitation concerning the right to live, human dignity, personal growth, participation in working life, as well as recreation/vacation main-streaming. The fundamental social-ethical position posited is one of acceptance of disability in every phase of human life, practically expressed in terms of trusting in the benefit of educational enhancement even in severe disability, as well as in assuming responsibility for disabled persons' living conditions.

[Handicap--negative variant of the "normal"--or else? Comments on the problem of attitude to deficits in rehabilitation and ethical principles]

Uncertainty as to what exactly is comprised by disability is quite frequently encountered not only in the general public but also among rehabilitation workers. The "normal" is deemed the desirable, and "disability" turns into its negative counterpart. Attention is focussing on the deficits that appear on measuring and comparing. A critical discussion of deficit orientation in education and care of disabled persons is needed. Isolated identification of and attendance to deviations must be overcome by interdisciplinarity and team work, in order to pay due respect to the person as a whole, to his or her social and personal identity. Also, fundamental issues of the current ethics discussion in special education arise in this context. Shown on the example of J. J. Rousseau, reference to philosophical or educational "authorities" may turn out to be misguided.

[Independent living skills for physically handicapped students with profound disability]

Traditional educational curricula are inadequate for physically disabled students with very severe consequences of disablement, as they are insufficiently geared toward building Independent Living skills. Typical of their post-school situation nowadays, only few of them are in a position of making a direct transition into vocational training. The majority continues to need intensive educational-therapeutic services. The schools for the physically disabled seek to smoothen their transition into adult life by leaving-grade programmes aimed at providing opportunities for work-related experience as well as at building coping skills for day-to-day living. The work and life preparation programme represents a special organizational and didactical conception in this context, where the demands of adult life serve as the starting point for developing the learning and educational goals to be attained.

Ro 42-5892 is a potent orally active renin inhibitor in primates

The goal of the present study was to characterize the new renin inhibitor Ro 42-5892 in vitro and in vivo. In vitro, Ro 42-5892 inhibited purified human renin and human plasma renin specifically with an IC50 of 0.7 nM and 0.8 nM, respectively. In vivo, Ro 42-5892 reduced mean arterial blood pressure in sodium-depleted marmosets and squirrel monkeys with as low a dose as 0.1 mg/kg orally. Higher doses reduced pressure by 30-35 mm Hg in both species. The duration of blood pressure decrease with 3 mg/kg orally was more than 24 hours. Maximal changes of plasma renin activity, immunoreactive angiotensin I, and immunoreactive angiotensin II were observed at 15 minutes. Renin was reduced by 74 +/- 31%, angiotensin I by 85 +/- 14%, angiotensin II by 89 +/- 17%, and immunoreactive active renin was increased by 70 +/- 39%. However, unlike pressure, these maximal effects were only transient with complete recovery of renin at 60 minutes under still reduced levels of angiotensin I (61 +/- 24%) and angiotensin II (71 +/- 38%) and increased concentrations of active renin (86 +/- 30%). The blood pressure lowering was due to specific renin inhibition as exemplified by the influence of the kidney, sodium status, species, or stereoselectivity. Moreover, the reduction of arterial blood pressure was similar to the action of the angiotensin converting enzyme inhibitor cilazapril and was not associated with reflex tachycardia in contrast to the pure vasodilator minoxidil. We conclude that Ro 42-5892 is a potent orally active renin inhibitor acting mainly by inhibition of renin in an extraplasmatic compartment.

[Didactic problems of education and instruction of patients with craniocerebral trauma]

While concepts for the solution of didactical-methodological problems are available for brain-injured children and young people, such concepts are almost nonexistent for adults with craniocerebral trauma sequels. A case example is presented from an educationist perspective, illustrating the disruptive impact of craniocerebral trauma on the person's biography. Didactical and methodological problems not only arise from deficient cognitive functioning but also due to the psychosocial impact of severe brain trauma. Inter alia dealt with is the question of whether an independent didactical approach is needed, or whether concepts derived from general didactics can be applied. For learners with craniocerebral trauma, "learning theory-based didactics" is an especially suitable model; a brief description is given, and its application to the specific situation of this population outlined. People with brain trauma display problems in knowledge acquisition and concept formation (cognitive learning), in transfer of learning content and performance control. Though an independent didactical concept may not be necessary, it is however crucial that in respect of the teaching/learning processes in this population, due attention is being paid to methodological principles applied in the special education field.

Ionic channels in synaptic vesicles: are they involved in transmitter release?

Synaptic vesicles were isolated from the nerve terminals of Torpedo electric organ. After fusion, 'giant' vesicles were formed which could be examined by the patch clamp technique. One of the cationic channels, the P channel, shows a small preference for K+ compared to Na+ and has multiple conductance levels. Its rate of opening is voltage and calcium dependent. Fractal analysis of the P channels reveals that its behaviour does not seem to be fractal in nature. At voltages where only one conductance level is observed, fractal analysis shows at least one discrete open state and at least two discrete closed states. There are considerable similarities between the P channel and channels found in granules from the hypophysis. These channels resemble, in turn, the channels found in gap junctions. Therefore, it is not unwarranted to speculate that a gap-junction-like communication between the secretory vesicle and the extracellular space may occur during exocytosis.

[Changes in the urinary protein pattern in SDS polyacrylamide gel electrophoresis in normal and hypertensive pregnancies]

The urinary protein pattern was determined in 46 healthy male and female subjects, 64 patients with an uncomplicated course of pregnancy and 88 hypertensive pregnant women by use of a special urine preparation and a modified SDS-polyacrylamide gel electrophoresis (SDS-PAGE). There were no differences in the protein electrophoresis pattern between the control subjects, independent of sex and age, and the pregnant women. The number of protein bands did not change in the course of pregnancy and in the post partum period. In both groups, an intensively stained protein band with an apparent molecular weight of 105 kD was detected. In 71 of the 88 hypertensive pregnant women we found a marked reduction in intensity or complete disappearance of the 105 kD protein band. Follow-up analysis in 30 of these pregnant women showed, that in 24 cases disappearance of the 105 kD band occurred simultaneously with and in 6 women before clinical manifestation of the disease. There were no differences in the protein electrophoresis pattern between patients with preexisting renal or hypertensive disease and hypertensive women without a complicated history. In 49 of the 52 hypertensive pregnant women complete reappearance of the 105 kD band was observed 2 to 14 days after delivery. By using silver staining and Western blot, the 105 kD band was identified as Tamm-Horsfall protein. Our findings may reflect a transitory tubular dysfunction in cases of preeclampsia and support the hypothesis of an immunological pathogenesis of the disease.

Uptake of GABA by rat brain synaptic vesicles isolated by a new procedure

Uptake of GABA was demonstrated in rat brain synaptic vesicles which were prepared by a new and efficient procedure. The uptake activity co-purified with the synaptic vesicles during the isolation procedure. The purity of the vesicle fraction was rigorously examined by analysis of marker enzymes and marker proteins and also by immunogold electron microscopy using antibodies against p38 (synaptophysin). Contamination by other cellular components was negligible, indicating that GABA uptake by the synaptic vesicle fraction is specific for synaptic vesicles and not due to the presence of other structure possessing GABA uptake or binding activities. GABA uptake was ATP dependent and similar to the uptake of glutamate, which was assayed for a comparison. Both uptake activities were independent of sodium. They were inhibited by the uncoupler carbonyl cyanide 4-(trifluoromethoxy)phenylhydrazone, indicating that the energy for the uptake is provided by an electrochemical proton gradient. This gradient is generated by a proton ATPase of the vacuolar type as suggested by the effects of various ATPase inhibitors on neurotransmitter uptake and proton pumping. Competition experiments revealed that the transporters for GABA and glutamate are selective for the respective neurotransmitters.

Ion channels in synaptic vesicles from Torpedo electric organ

A simple method has been developed for fusing synaptic vesicles into spherical structures 20-50 micron in diameter. The method has been applied to purified cholinergic synaptic vesicles from Torpedo electric organ, and the membrane properties of these fused structures have been studied by the "cell"-attached version of the patch clamp technique. A large conductance potassium-preferring channel, termed the P channel, was consistently observed in preparations of fused synaptic vesicles. The selectivity of the channel for potassium over sodium was approximately equal to 2.8-fold. Two major conductance levels were observed during P-channel activity, and their relative proportion was dependent on the voltage applied to the membrane through the patch pipette. P channels were not seen in fused preparations of purified Torpedo lipids, nor was the frequency of their occurrence increased in preparations enriched with plasma membrane or nonvesicular membranes. We suggest, therefore, that the P channels are components of the synaptic vesicle membrane. Their function in synaptic transmission physiology is still unknown.

Cholinergic vesicle specific proteoglycan: stability in isolated vesicles and in synaptosomes during induced transmitter release

Exposure of synaptosomes isolated from the electric organ of Torpedo marmorata to conditions that promote the release of acetylcholine does not cause the co-release of a vesicle specific proteoglycan. Proteoglycan within synaptosomes is quite stable during various incubation conditions as measured by immune dot blotting. Isolated vesicles from Torpedo also retain their proteoglycan immunoreactivity when exposed to a variety of incubation conditions. Lysis of vesicles in H2O, treatment with pH 11.5 buffer, or exposure to high ionic strength (2 M KCl) results in the loss of acetylcholine or ATP while the proteoglycan is retained by vesicle membranes. Only treatment with Nonidet P-40 releases proteoglycan from vesicles or synaptosomes and free proteoglycan immunoreactivity is then susceptible to degradation by trypsin or heparinase. These results suggest that the proteoglycan is an integral component of vesicle membranes and is at least in the synaptosomal preparation not subject to extensive co-release with acetylcholine or ATP.

Synaptic vesicles in electromotoneurones. II. Heterogeneity of populations is expressed in uptake properties; exocytosis and insertion of a core proteoglycan into the extracellular matrix

The three populations of synaptic vesicles in electromotor nerve terminals were analysed quantitatively. Empty vesicles (VP0), fully charged vesicles (VP1) and charged but smaller VP2-type vesicles are present in approximately equal amounts in the nerve terminal. The populations show differences in the kinetics of in vitro uptake of acetylcholine, ATP and Ca2+. VP0 and VP2 accumulate acetylcholine and ATP but no Ca2+, whereas VP1 shows negligible acetylcholine and ATP but high Ca2+ uptake. Thus the expression of uptake properties of this secretory organelle depend on the stage it has reached in its life cycle and might constitute a signal for processing. VP2 was found to contain much less core proteoglycan than VP0 and VP1 indicating that part of it has been lost by exocytosis. In synaptic extracellular matrix containing fractions an antigen is detectable that cross-reacts with an antiserum against the vesicle proteoglycan. This material elutes upon gel filtration in a position similar to a smaller form of proteoglycan found in vesicles. We conclude that the electromotor nerve terminal releases a proteoglycan by the regulated secretory pathway that is deposited in the extracellular matrix. It might have a function in keeping pre- and postsynaptic structures in alignment constituting a transsynaptic signal. Based on the findings described, a model of the vesicles' life-cycle is discussed, whereby the VP2 population is the major source of quantal release of acetylcholine.