Singlet oxygen luminescence kinetics in a heterogeneous environment – identification of the photosensitizer localization in small unilamellar vesicles

Singlet oxygen luminescence kinetics in microheterogeneous environment reflect the localization of the photosensitizer.

[Risk communication of the Federal Institute for Risk Assessment during a food-related outbreak]

Information about and explanation of risks as well as the initiation of behavioral changes and preventive actions are core tasks of risk communication. During the EHEC/HUS outbreak in spring 2011, the governmental agencies responsible for risk communication mainly focused on these tasks. In general, risk communication is understood as a continuous, long-term process that aims at an adequate handling of risks. In contrast, crisis communication is focused rather on an acute event and aims at timely information and behavioral measures. During the EHEC/HUS outbreak, risk communication partly changed over to crisis communication. The risk communication activities of the Federal Institute for Risk Assessment (Bundesinstitüt für Risikobewertung, BfR) during the EHEC/HUS outbreak are presented here. The results of a representative survey that was conducted in Germany shortly after the outbreak show details of the success of these risk communication activities. Finally, the necessity of communication about scientific uncertainty is addressed and new ways in risk communication with regard to new media are highlighted.

Alpha-1-Fetoprotein (AFP): international proficiency study with different test systems

BACKGROUND

The present proficiency study aimed to elucidate the comparability and reliability of test systems for the determination of AFP concentrations.

METHODS

25 laboratories using 8 different commercial test systems used liquid BIOREF-AFP control serum in their routine internal quality control over a period of one year. For statistical analysis the results were collected centrally.

RESULTS

The statistical analysis of the test results revealed considerable variation for the different laboratories. The deviations of the mean values of different laboratories from the overall mean value varied between 0.1 and 26.1%, and for most of the laboratories the deviation was round about 10%. The precision of measured values in the individual laboratories was in most cases acceptable: Nevertheless, the coefficients of variation of the individual laboratories ranged from 13 to 16.1%.

CONCLUSIONS

In conclusion, this study indicates that AFP results vary between different laboratories albeit an international standard for AFP is available. Therefore, every laboratory should participate in external ring studies and should use a quality control serum independent of the test kit manufacturer for the internal quality control.

Water-Soluble Polymer Conjugates of ZnPP for Photodynamic Tumor Therapy

Zn-protoporphyrin (ZnPP) is a promising candidate for cancer therapy. It is known to inhibit heme-oxygenase-1 (HO-1), resulting in suppressed biliverdin/bilirubin production accompanying lowered antioxidative capacity. As a consequence, a significant suppression of tumor growth in vivo was reported. Recent findings also showed that ZnPP efficiently generated reactive singlet oxygen under illumination of visible light. In the present report, we describe the photosensitizing capabilities of water-soluble polymer conjugates of ZnPP as novel compounds for photodynamic therapy against solid tumors. The polymer conjugation made ZnPP water-soluble, thus possible for injection for its aqueous solution. The cellular uptake and photobiological activity of ZnPP derivatives have been tested using a human T-cell leukemia cell line in vitro and demonstrated most potent phototoxic effects of SMA-ZnPP followed by PEG-ZnPP under aerobic conditions.

Lipid nanoparticles for skin penetration enhancement—correlation to drug localization within the particle matrix as determined by fluorescence and parelectric spectroscopy

With topical treatment of skin diseases, the requirement of a high and reproducible drug uptake often still is not met. Moreover, drug targeting to specific skin strata may improve the use of agents which are prone to cause local unwanted effects. Recent investigations have indicated that improved uptake and skin targeting may become feasible by means of nanoparticular systems such as solid lipid nanoparticles (SLN), nanostructured lipid carriers (NLC) and nanoemulsions (NE). Here we describe techniques to characterize drug loading to carrier systems and skin penetration profiles by using the lipophilic dye nile red as a model agent. Since the mode of drug association with the particle matrix may strongly influence the efficiency of skin targeting, parelectric spectroscopy (PS) was used to differentiate between matrix incorporation and attachment to the particle surface and fluorescence spectroscopy (FS) to solve dye distribution within NLC particles. Nile red was incorporated into the lipid matrix or the covering tensed shell, respectively, of SLN and NLC with all the lipids studied (Compritol, Precirol, oleic acid, Miglyol). In NLC, the dye was enriched in the liquid phase. Next, nile red concentrations were followed by image analysis of vertical sections of pigskin treated with dye-loaded nanoparticular dispersions and an oil-in-water cream for 4 and 8 h in vitro. Following the SLN dispersions, dye penetration increased about fourfold over the uptake obtained following the cream. NLC turned out less potent (<threefold increase) and penetration appeared even reduced when applying a NE. In contrast to previous studies with glucocorticoids attached to the surface of SLN, a targeting effect was not detected here. Therefore, drug targeting appears to be more strictly related to the mode of interaction of drug and particle than penetration enhancement.

Methylammonium groups at the solid walls of nanometer-sized, water-filled monolayer gaps as binding sites for a tetraanionic porphyrin

Long-chain hydrosulfides containing two secondary amide functions and either electron-poor or electron-rich carbon-carbon double bonds were self-assembled on gold surfaces around a flat-lying, octaanionic porphyrin. Rigid and reactive surface monolayers with 2 nm-wide, porphyrin-based gaps were thus obtained. The gold electrodes were then immersed in water, and the double bonds on the gaps' surfaces reacted with methylamine. It was added to the double bonds either by Michael addition or by bromination with hypobromite followed by methylamine substitution. Only the double bonds at the border of the gaps were accessible to methylamine dissolved in the bulk water volume and could react. The walls of the rigid membrane gaps now contained methylammonium groups at the sites of the double bonds in defined heights. A tetracationic copper(II) porphyrinate could not diffuse any more into the gap and did not quench the fluorescence of the octaanionic porphyrin on the bottom of the gap. A tetraanionic porphyrin, on the other hand, was fixated by the ring of ammonium groups. The bound porphyrin then acted as molecular cover for the gap with respect to ferricyanide transport from bulk water to the electrode. It was removed by raising the pH to a value of 12, where the methylammonium groups were neutralized to amines. Lowering the pH to 7 again and addition of more of the anionic porphyrin reclosed the gap.The porphyrin "cover" should be localized at distances of 8-10 and 20 A from the bottom porphyrin by multiple charge interactions. The 8-10 A distance is ideal for studies of photoinduced electron transfer between two porphyrin monomers of different redox potential. Furthermore it was found, that redox-active tyrosine could be trapped in the water volume above the porphyrin on gold.

Auditory memory in congenitally blind adults: a behavioral-electrophysiological investigation

Blind people must rely more than sighted people on auditory input in order to acquire information about the world. The present study was designed to test the hypothesis that blind people have better memory than sighted individuals for auditory verbal material and specifically to determine whether memory encoding and/or retrieval are improved in blind adults. An incidental memory paradigm was employed in which 11 congenitally blind people and 11 matched sighted controls first listened to 80 sentences which ended either with a semantically appropriate or inappropriate word. Immediately following, the recognition phase occurred, in which all sentence terminal words were presented again randomly intermixed with the same number of new words. Participants indicated whether or not they had heard the word in the initial study phase. Event-related brain potentials (ERPs) were recorded from 28 electrode positions during both the encoding and the retrieval phase. Blind participants' memory performance was superior to that of sighted controls. In addition, during the recognition phase, previously presented words elicited ERPs with larger positive amplitudes than new words, particularly over the right hemisphere. During the study phase, words that would subsequently be recognized elicited a more pronounced late positive potential than words that were not subsequently recognized. These effects were reliable in the congenitally blind participants but could only be obtained in the subgroup of sighted participants who had the highest memory performance. These results imply that blind people encode auditory verbal material more efficiently than matched sighted controls and that this in turn allows them to recognize these items with a higher probability.

Event-related potentials during auditory language processing in congenitally blind and sighted people

While behavioral studies have documented delayed language acquisition in blind children, other studies have revealed better speech discrimination abilities for blind than sighted adults. Several brain imaging studies have provided evidence for cortical reorganization due to visual deprivation but the cerebral organization of language in blind humans is not known yet. We hypothesized that the increasing specialization of language systems normally observed during development may not take place to the same degree in blind individuals since posterior visual areas do not receive their adequate input. On the other hand, we hypothesized that blind people, due to their greater reliance upon the auditory language signal, may process speech faster than sighted people. To test these assumptions, event-related potentials were recorded while 11 congenitally blind and 11 sighted adults matched in age, gender, handedness and education were engaged in a language task. Participants listened to sentences in order to decide after each sentence if it was meaningful or not. Incongruous sentence-final words elicited an N400 effect in both groups. The N400 effect had a left-lateralized fronto-central scalp distribution in the sighted but a symmetric and broad topography in the blind. Furthermore, the N400 effect started earlier in the blind than in the sighted. Closed class compared to open class sentence middle words elicited a more pronounced late negativity in the blind than in the sighted. These results suggest that blind people process auditory language stimuli faster than sighted people and that some language functions may be reorganized in the blind.

Inhibition of return and oculomotor control in the blind

Our attentional systems orient reflexively to novel environmental stimuli. Such attentive orienting is typically followed by a prolonged period of inhibition, known as inhibition of return (IOR), thought to be linked to the eye movement system. It is widely believed that IOR may provide a tagging mechanism that prevents perseveration, and thus facilitates attentional search. Using a tactile variant of the peripheral spatial cuing paradigm, we show IOR in congenitally blind adults and in an individual who had no eyes. These results demonstrate for the first time that spatial IOR can occur in the absence of oculomotor control.

Photophysical studies of the pheophorbide a dimer

This work reports on a monomer-dimer equilibrium state of pheophorbide a in solution. A methodology for controlling the equilibrium constant by use of temperature and solvent variation is described. The absorption spectrum of the dimer is calculated, using different prepared equilibria of monomer and dimer in solution. We propose that these aggregates provide a good model for understanding the dimerization process in tetrapyrroles.

Time-resolved detection of singlet oxygen luminescence in red-cell ghost suspensions: concerning a signal component that can be attributed to 1O2 luminescence from the inside of a native membrane

For about ten years, it has been debated whether in principle it is possible to detect 1O2 located within the cell membrane by performing experiments with cell suspensions or even in tissue. In this paper we present our investigations on photosensitized red-cell ghost suspensions (RCGSs) and our strategy for the detection of luminescence of singlet oxygen (1O2) from the inside of the cell membrane. Using a very sensitive apparatus for time-resolved 1O2 detection, a very promising sensitizer and an adequate experimental strategy, a very small amount of the detected luminescence indeed can be attributed to 1O2 from the inside of the ghost membrane.

Spatial attention to central and peripheral auditory stimuli as indexed by event-related potentials

Young adult subjects attended selectively to brief noise bursts delivered in free-field via central and peripheral arrays of four loudspeakers each that were arranged along a semi-circle extending from the midline to 90 degrees right of center. Frequent "standard" stimuli (90%) and infrequent "target/deviant" stimuli (10%) of increased bandwidth were delivered at a fast rate in random order and equiprobably from all eight speakers. In separate runs, the subject's task was to selectively attend to the center or rightmost speaker, and to press a button to the infrequent "target" stimuli occurring at the designated (spatial) location. Behavioral detection rates and concurrently recorded event-related potentials (ERPs) indicated that auditory attention was deployed as a finely tuned gradient around the attended source. The attentional gradients were steeper for the central than the peripheral array, indicating that attention can be more sharply focused upon sound sources directly in front of the listener. The ERP data suggested that selection for location is accomplished in two distinct stages, with an initial broadly tuned filtering, followed by a more narrowly focused selection of attended-location deviants.

Improved auditory spatial tuning in blind humans

Despite reports of improved auditory discrimination capabilities in blind humans and visually deprived animals, there is no general agreement as to the nature or pervasiveness of such compensatory sensory enhancements. Neuroimaging studies have pointed out differences in cerebral organization between blind and sighted humans, but the relationship between these altered cortical activation patterns and auditory sensory acuity remains unclear. Here we compare behavioural and electrophysiological indices of spatial tuning within central and peripheral auditory space in congenitally blind and normally sighted but blindfolded adults to test the hypothesis (raised by earlier studies of the effects of auditory deprivation on visual processing) that the effects of visual deprivation might be more pronounced for processing peripheral sounds. We find that blind participants displayed localization abilities that were superior to those of sighted controls, but only when attending to sounds in peripheral auditory space. Electrophysiological recordings obtained at the same time revealed sharper tuning of early spatial attention mechanisms in the blind subjects. Differences in the scalp distribution of brain electrical activity between the two groups suggest a compensatory reorganization of brain areas in the blind that may contribute to the improved spatial resolution for peripheral sound sources.

Effects of interstimulus interval on auditory event-related potentials in congenitally blind and normally sighted humans

To test the hypothesis of auditory compensation after early visual deprivation, congenitally blind and sighted adults performed an auditory discrimination task. They had to detect a rare target tone among frequent standard tones. Stimuli were presented with different interstimulus intervals (ISIs) (200, 1000, 2000 ms) and the auditory-event related potentials to all tones and reaction times to targets were recorded. Increasing ISIs resulted in an increasing amplitude of the vertex response (N1-P2) in both groups, but this amplitude recovery was more pronounced in the blind. Furthermore, targets elicited larger and more posteriorly distributed N2 responses in the blind than in the sighted. Since target detection times were shorter in the blind as well, these findings imply compensatory adaptations within the auditory modality in humans blind from birth.

13(2)-hydroxy-bacteriopheophorbide a methyl ester pharmacokinetics measurements with fluorescence versus absorption spectroscopy. Is there a difference?

OBJECTIVE

Quantification of photosensitizer concentration in tissue improves the planning and, subsequently, the outcome of photodynamic therapy. This study was designed to determine if the method of photosensitizer evaluation influences the accuracy of pharmacokinetic results.

MATERIALS AND METHODS

In vivo 13(2)-Hydroxy-bacteriopheophorbide a methyl ester (13(2)-OH-BPME) pharmacokinetics in mice bearing LEWIS lung carcinoma was studied using fluorescence in situ and absorption spectroscopy (following photosensitizer chemical extraction) as photosensitizer quantification methods. The correlation of 13(2)-OH-BPME fluorescence intensity and its concentration using the absorption spectroscopy were determined for each tissue.

RESULTS

The parenchymatous organs showed maximum 13(2)-OH-BPME concentration and fluorescence intensity at 2 h post-injection (lung, liver, spleen), and at 2 h post-injection in the kidney with both quantification methods (identical correlation). There was a difference in the time of maximum photosensitizer fluorescence intensity and its concentration in tumor, muscle, and skin (low correlation). The time of maximum fluorescence intensity in muscle, skin, and tumor was at 4 h, 12 h, and 12 h post injection respectively while its maximum concentration was at 2 h, 4 h, and 8 h post-injection.

CONCLUSION

The method of photosensitizer evaluation affects the accuracy of its pharmacokinetic results.

Pharmacokinetic analysis of octa-alpha-butyloxy-zinc phthalocyanine in mice bearing Lewis lung carcinoma

OBJECTIVE

In this study, the pharmacokinetics of octa-alpha-butyloxy-zinc phthalocyanine (8-alpha-bo-ZnPc) was studied with regard to Lewis lung carcinoma in mice after intravenous administration of 7.8 mumole/kg body weight at different incubation intervals.

SUMMARY BACKGROUND DATA

The newly synthesized potential photosensitizer 8-alpha-bo-ZnPc is characterized by a high absorption coefficient at the far red wavelength (735 nm) with a good singlet oxygen quantum yield.

METHODS

After intravenous administration of 7.8 mumole/kg body weight in mice bearing Lewis lung carcinoma, the accumulated photosensitizer was chemically extracted (at incubation intervals of 2, 6, 12, 24, 48, and 168 hours) from selected tissues, and the concentrations were measured by absorption spectroscopy.

RESULTS

The parenchymatous organs, liver, and spleen showed maximum 8-alpha-bo-ZnPc concentrations after 6 hours of incubation. An extensive uptake was detected in lung extracts taken at 6, 12, 24, and 48 hours. The malignant tissue did not accumulate high 8-alpha-bo-ZnPc during the entire investigation period. The photosensitizer extracted from muscle, representing normal tumor-surrounding tissue and skin, was even lower.

CONCLUSIONS

Because of the extremely low accumulation rate of the tumor, 8-alpha-bo-ZnPc is suggested to be administered topically or in combination with a suitable carrier system in order to increase the photosensitizer concentration in the target tissue, as well as to decrease the loss of dye to other tissues.

[Memory traces in EEG]

The paper gives a brief overview of five experimental approaches in which memory processes were studied by means of event-related brain potentials (ERPs). Some of the results were already published in English (Study 1), while others are new and will be reported in greater length as full paper elsewhere (Studies 2, 3, 4, and 5). Study 1 revealed that retrieval of information from episodic long-term memory is accompanied by a systematic slow negative potential. The topography of this slow wave depends on the quality of the reactivated information (spatial vs. verbal), and its amplitude reflects the difficulty of the retrieval process. In experiment 2 ERPs were recorded while subjects acquired either explicit or implicit knowledge about a sequential stimulus-response pattern. The data suggest that explicit learners who posses verbalizable knowledge about sequential dependencies have formed both perceptual and motor representations, while implicit learners have formed motor representations only. In study 3 fact retrieval in mental arithmetic was activated by a verification task. Incongruent solutions evoked an arithmetic N400-effect whose amplitude varied with the associative distance between an expected and an actually perceived solution to a multiplication problem. In study 4 ERPs were recorded during mental rotation tasks. A set of experiments revealed that mental rotation is always accompanied by a systematic negative variation over the parietal cortex. The amplitude of this "rotation specific negativity" increases with an increasing angular disparity between a perceived sign and its normal upright template. It was shown that this negativity is functionally distinct from a P300-complex which is often superimposed on it within the same latency window. Finally, study 5 examined ERPs in a sentence reading task in which grammatically legal but infrequent sentence constructions had to be processed. A left-anterior negativity was observed whenever an explicit case marker (the definite article in German) signalled a nominal phrase at a noncanonical position. The LAN phenomenon appears to be a manifestation of a syntax processor which performes a first-pass formal analysis of a sentence and which possibly allocates working memory resources whenever a word cannot be assigned immediately to an expected propositional role.

Different cortical activation patterns in blind and sighted humans during encoding and transformation of haptic images

In this study, we investigated whether the occipital cortex of blind humans is activated during haptic perception and/or transformation of a haptic image. Slow event-related brain potentials were monitored from 18 electrodes in 12 sighted and 15 congenitally blind participants while they were engaged in a haptic mental rotation task. In both groups, slow negative shifts appeared over (a) the frontal cortex at the beginning of each processing episode, (b) the left-central to parietal cortex during encoding and maintaining of a haptic image, and (c) the central to parietal cortex during image transformation. A pronounced slow negative potential over the occipital cortex emerged only in the blind individuals and was time-locked to the processing epochs. Its amplitude increased with the amount of processing load. The slow wave effects observed in the blind individuals could indicate that occipital areas participate in specific, nonvisual functions or they could reflect a coactivation of these areas whenever the activation level of task-specific processing modules located elsewhere in the cortex is raised by nonspecific thalamocortical input.

Slow negative brain potentials as reflections of specific modular resources of cognition

The paper summarizes a series of experiments in which the topography and the amplitude of slow event-related brain potentials (slow ERPs) was studied in cognitive tasks which imposed different amounts of load on functionally distinct processing modules. The results suggest that the topography of slow ERPs reflects the relative activation/inactivation of distinct cortical cell assemblies while the absolute amplitude of the negative maximum seems to reflect how much a particular cell assembly is activated at a particular time. Translated into the terminology of cognitive resource theories one could say that tasks which evoke distinct slow wave patterns draw on independent resources. Likewise, the amplitude of a slow wave pattern could be related to the construct of resource allocation, i.e. the larger the amplitude of a slow wave pattern the more resources of a particular type are allocated to a task. These findings are discussed with respect to possible generator mechanism of slow waves and in relation to possible causes of capacity limitations of the human information processing system.

Event-related potentials during auditory and somatosensory discrimination in sighted and blind human subjects

The objective of the present study was to test if and to what extent phasic and tonic event-related potentials of the human EEG may reflect phenomena of cortical plasticity. In particular, it was tested if the occipital cortex of blind subjects participates in the processing of non-visual stimuli. To this end, 12 blind and 12 blindfolded sighted subjects were tested in an auditory and a somatosensory discrimination task with 2 levels of discrimination difficulty. Slow and fast event-related potentials were recorded from 18 scalp electrodes. In addition to the negative slow waves found in sighted subjects over frontal and central sites during auditory and somatosensory discrimination, a pronounced negative wave was revealed in the blind also over occipital brain areas. These negative shifts were time-locked to the train of stimuli which had to be monitored with sustained attention, i.e. they rised and resolved with the beginning and the end of a 20-s discrimination time epoch. The P300 complex, on the other hand, which is a slow positive deflection over the posterior part of the scalp and which follows rare and task-relevant events 200-800 ms after stimulus onset was significantly smaller at occipital electrodes in the blind than in the sighted subjects. Combined with neurophysiological and neuronanatomical evidence originating from studies with visually deprived animals, these data suggest that the occipital cortex of blind human subjects is coactivated whenever the system is engaged in a task which requires sustained attention and is less effectively inhibited at the end of a perceptual time epoch. In total, the data cast doubt on the hypothesis that the occipital cortex of blind subjects participates in modality-specific non-visual information processing.

[Epidemiological characterization of a pestivirus isolate from a viremic pig out of a mixed pig-cattle herd]

A pestivirus isolated from a healthy pig out of a mixed pig-cattle holding was identified by use of monoclonal antibodies as a porcine virus related or identical to bovine viral diarrhoea (BVD) virus. About 7% of the pigs of this herd showed neutralizing antibodies (nab) against BVD and Border Disease (BD) virus and against the homologous porcine nonclassical swine fever (CSF) pestivirus isolate 10421/Han94. The nab titres against this virus were clearly higher than against CSF virus strain Alfort/187. Amongst the cattle kept in the farm no BVD viraemic animal was detected. About 13% of them showed nab to BVD virus with higher titres against the BVD virus strain NADL than against the porcine pestivirus virus isolate 10421/Han94. There was no of a BVD virus transmission from the cattle to the pigs within this herd. The problem of misinterpretation of non-CSF virus isolation from pigs is discussed. The necessity of identifying pestiviruses of porcine origin by use of species-specific monoclonal antibodies is stressed in order to prevent erroneous declarations of CSF outbreaks.

[Clinical experiences in the use of para-immunity inducers in cattle during animal exhibitions]

IBR positive cattle after vaccination with dead vaccine may excrete IBR/IPV (BHV-1) virus when facing a stress situation. On cattle exhibitions the share of such individuals may vary between 8 and 34%. Since 1988 in order to protect animals against infections IBR negative cattle and cows on 7 regional, one national and one international exhibitions were treated with Duphamun and Baypamun, respectively. After returning of animals to their owner IBR outbreaks were confirmed in 8 forms. This is low incidence compared with breeding exhibitions that where held in the same place or elsewhere. For protection against BHV-1 virus infection the use of a para-immunity-inducer is recommended. Nevertheless strict quarantine and following serological investigations are essential.

Synthesis and application of new microcarriers for animal cell culture. Part I: Design of polystyrene based microcarriers

In this work (Part I), surface modified styrene polymers as new microcarrier material for animal cell culture were extensively investigated. The first synthesis steps--carried out by chloromethylation, sulphonation and nitration of the polystyrene matrix--resulted in precursors with a defined surface layer thickness. The obtained hydrophobic bulk phase showed a limited absorption of hydrophilic media components compared to polysaccharides matrices like dextran. By varying reaction conditions for microcarrier synthesis and/or by using similar styrene type polymer matrices like polyvinyltoluene, the specific density (1.028-1.05 g/cm3) of the microcarrier matrix was adjusted without problems. Chemical varying of the microcarrier surface by reaction of the precursors with different amines, saccharides or proteins led to new microcarriers with optimal conditions for cell adhesion and cell growth. All biological investigations were carried out with a BHK 21 (c-13) cell line. Detailed results will be discussed and summarized in Part II of this work.

Synthesis and application of new microcarriers for animal cell culture. Part II: Application of polystyrene microcarriers

In this work (Part II) the application of new polystyrene based microcarriers in cell culture technology is demonstrated. Carriers with a variety of surface modifications were tested as a growth support for cell line BHK 21. The growth behavior of the cells and cell to surface attachment were compared to Cytodex 3 (Pharmacia), which was used as a reference carrier. To select carriers with growth supporting surfaces, broad screening in petri dish experiments was carried out. Candidates with the highest growth rates were investigated in spinner flash experiments in further detail. Polystyrene carrier with a surface modification like triethylamine, maltamine or N-methylglucosamine were able to support growth as good or better as the reference carrier Cytodex 3. Economies of ingredients and ease in laboratory handling could make amine-modified polystyrenes a competitive alternative to currently commercially available microcarrier types.

[Field infection with BVD virus in swine: epidemiology and diagnosis]

In a pig breeding herd in Lower Saxony infertility of breeding sows had been repeatedly observed. Growth retardation and post mortem findings in two piglets gave clinical indication to swine fever/hog cholera. A virus was isolated and typed by monoclonal antibodies as pestivirus not identical with hog cholera virus (HCV). In neutralization tests applying the field isolate, HCV and bovine viral diarrhea (BVD) virus the sera breeding sows and weaner pigs yielded high neutralizing antibody titres against the pestivirus field isolate but low titres against HCV. Specific antibodies against HCV were ruled out by a complex trapping blocking (CTB) ELISA. Intranasal inoculation of a weaner pig with spleen homogenate led to a short-termed viraemia without clinical signs but seroconversion with high antibody titres against the homologous pestivirus. In an in-contact pig no virus was detected and no antibody demonstrated within a period of 18 weeks.

Topographic differences of slow event-related brain potentials in blind and sighted adult human subjects during haptic mental rotation

Twelve blindfolded sighted, nine congenitally blind, and seven adventitiously blind subjects were tested in a haptic mental rotation task while slow event-related brain potentials in the EEG were recorded from 17 scalp locations. The overall topography of the slow wave pattern which prevailed during the task differed for sighted and for blind, but not for congenitally and adventitiously blind subjects. While the tactile stimuli were encoded, the blind showed a pronounced occipital and the sighted a pronounced frontal activation. The task-specific amplitude increment of a negative slow wave which can be understood as a manifestation of the process of mental rotation proper, showed a different topography for sighted and for blind subjects too. It had its maximum over central to parietal cortical areas in both groups, but it extended more towards occipital regions in the blind. In both groups, the effects were very similar to those observed in former studies with visual versions of the mental rotation task, i.e. the slow wave amplitude over central to parietal areas increased monotonously with an increasing angular disparity of the two stimuli to be compared. These results are discussed with respect to the question of whether visual deprivation in the blind can cause a reorganization of cortical representational maps.

[Use of an immunoenzyme histochemical method for the improvement of the etiologic diagnosis of Aujeszky's disease in swine]

With regard to the legal regulations for the diagnosis of Aujeszky's disease in pigs, a retrospective immunoenzymatic study was performed on brains of 20 pigs, in which Aujeszky's disease had been diagnosed based only on clinical, macroscopical and histological findings, although the etiological agent could not be demonstrated neither by immunofluorescent technique nor by virological cultivation. Applying the peroxidase-antiperoxidase-(PAP) method, in 6 of 20 animals (30%) viral antigen of porcine herpesvirus type 1 was demonstrated in situ in at least two of five different locations of the brain. Reasons for negative results in immunohistological and virological investigations are discussed and the significance of the performed immunoenzymatic technique is pointed out.

The determination of phytosphingosine-containing globotriaosylceramide from human kidney in the presence of lactosylceramide

Globotriaosylceramide, the natural substrate of alpha-galactosidase A (the enzyme deficient in Fabry's disease) was prepared from human kidney by repeated medium pressure chromatography on Lichroprep Si 60 (E. Merck) before and after peracetylation. The apparently homogeneous preparation migrating as a single band on HPTLC was analysed by fast atom bombardment mass spectrometry and 1H-NMR at 500 MHz. It was found that in this fraction two major molecular species were comigrating: Gal alpha 1-4Gal beta 1-4Glc beta 1-1ceramide with nervonic and lignoceric acid linked to phytosphingosine and Gal beta 1-4Glc beta 1-1 ceramide with palmitic acid linked to sphingosine.

[The relation between sperm motility and the content of unsaturated fatty acids as well as the osmotic behavior of human spermatozoa]

The relations between sperm motility and the content of lipids and fatty acids in sperm cells were investigated. In addition the osmotic volume changes of sperm cells were studied, by determination of progressive sperm motility, measurement of relative concentration of lipid-peroxy radicals in seminal plasma using chemoluminescence technique, gas-chromatographic determination of fatty acid pattern in sperm cells and in seminal plasma and by electronic measurement of the sperm cell volume. The impulse installment of chemoluminescence increased during the time of storage of the ejaculate. In contrast, this phenomenon was not observed in pure seminal plasma prepared by centrifugation immediately after liquefaction. The pattern of phospholipids and free fatty acids changed during storage of the ejaculate both in sperm cells and in seminal plasma. Sperm cells showed a significant increase of volume under hypotonic stress. The increase of volume is more distinct in spermatozoa with high progressive motility as in spermatozoa with low progressive motility. The determination of initial and late progressive motility enables the differentiation of two groups of sperm populations: one group with a medium initial motility and a normal decrease of motility during the following time and another group with excellent initial motility and an extreme decrease of motility following. The second group is characterized by an especially distinct increase of volume under hypotonic conditions.

Influence of nourseothricin on growth and secondary metabolism of Streptomyces noursei JA 3890b

The nourseothricin-producing S. noursei strain JA 3890b possessed a high degree of resistance to its own antibiotic when grown in submerged cultures started from mycelium samples as inocula. In contrast, both the outgrowth of spores and the development of surface colonies from mycelium samples were severely inhibited in the presence of relatively low concentrations of nourseothricin, suggesting that the producer organism is susceptible to the autotoxic metabolite in particular stages of its development. Nourseothricin production by submerged cultures has been found to be independent of negative feedback regulation by the antibiotic.

Uptake of nourseothricin by the producing microorganism, Streptomyces noursei

The uptake of 14C-(U)-nourseothricin by stationary phase mycelium of Streptomyces noursei JA 3890 b-NG 13/14 was demonstrated. An energy-dependent transport system appears to be involved in the transport of the antibiotic. Relatively large quantities of the antibiotic were adsorbed to the surface of mycelium. Degradation of nourseothricin by the producing microorganism was not detectable.

[Adrenoleukodystrophy in a pair of siblings]

The diagnosis of adrenoleukodystrophy (ALD) in two brothers was confirmed by the analysis of long-chain fatty acids in cultured skin fibroblasts. The 23 year old brother was treated for Addison's disease at the age of 7 years. His first symptoms of ALD developed at the age of 22. These were lack of concentration and compulsive disorder. The younger brother was noted to show behavioural changes and a decreased performance at school at age 9. The disease then progressed rapidly. Variability and diagnostic procedures are discussed in this report.

[Compression syndrome of the upper thoracic outlet (thoracic outlet syndrome)--report on a 13-year-old girl]

The thoracic-outlet-syndrome, a symptom complex consisting of arterial, venous and neural disorders of the upper extremity, is caused by compression of the neurovascular structures between the clavicle and the first rib. Other reasons are congenital abnormalities like a cervical rib, an abnormal first rib, acquired anatomic lesions like fractures and traumata or functional factors. The younger-and middle-age groups are most commonly involved. The symptoms are depending upon the point at which compression occurs and include pain, paresthesias, numbness, fatigue, pallor, coolness or swelling and enlargement of the arms. At physical examination a systolic murmur is heard in the supraclavicular region in 30 percent and the pulse of the upper extremity often is reduced. Diagnostic measurements include roentgenogram of the chest and the cervical spine, pulsed doppler-ultrasonography, nerve conduction-velocity testing and an arterio-venography. Treatment is nonoperative in patients with mild symptoms (shoulder-girdle-exercises) and operative in patients with severe or persistent symptoms. The operative treatment of choice is resection of the first rib by an axillary route. Risks are minimal, and the results are good to excellent in 90% of the cases. Because the thoracic outlet syndrome is very rare in childhood, we report a 13 year old girl which has undergone bilateral operation with excellent result.