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Showing papers by "University of Tübingen published in 1990"


Journal ArticleDOI
TL;DR: The cyclic heptapeptide, microcystin‐LR, inhibits protein phosphatases 1 (PP1) and 2A (PP2A) with K i, values below 0.1 nM, and this results are strikingly similar to those obtained with the tumour promoter okadaic acid.

1,555 citations


Journal ArticleDOI
TL;DR: A correction method is proposed for proton spectroscopy, which uses the signal of prominent water protons as a reference for the water‐suppressed signal, and has a good resolution as shown by phantom measurements and brain and muscle spectra of volunteers.
Abstract: Spatially localized methods in spectroscopy often operate with magnetic field gradients for volume selection. The eddy currents induced by these gradients produce time-dependent shifts of the resonance frequency in the selected volume, which results in a distortion of the spectrum after Fourier transformation. In whole-body systems the complete compensation of eddy currents is a difficult procedure. To avoid this, a correction method is proposed for proton spectroscopy, which uses the signal of prominent water protons as a reference for the water-suppressed signal. The correction is performed in the time domain, dividing the water-suppressed signal by the phase factor of the water signal for each data point. The corrected spectra have a good resolution as shown by phantom measurements and brain and muscle spectra of volunteers.

585 citations


Journal ArticleDOI
TL;DR: Astrocytes that tightly appose endfeet onto the abluminal side of brain capillaries seem to be important for the induction and maintenance of the endothelial barrier.

498 citations


Journal ArticleDOI
TL;DR: In this paper, a gas chromatography method for the enantiomeric analysis of stable, volatile compounds is proposed, which can be used not only for polar diols and alcohols, derivatized hydroxycarboxylic acids, amino acids, sugars, and alkyl halides but also for nonpolar alkenes, cyclic saturated hydrocarbons, and metal π complexes.
Abstract: In investigations concerned with the phenomenon of molecular chirality, the use of gas chromatography for the enantiomeric analysis of stable, volatile compounds is a technique of steadily growing importance. [1] In the last three years an important breakthrough in gas-chro-matographic separation of enantiomers has been achieved by using alkylated cyclodextrins (α, β, and γ) as chiral stationary phases in high-resolution capillary columns. In academic and commercial practice two different and complementary strategies have been adopted up to now. In the first, alkylated cyclodextrins are diluted with polysiloxanes and coated on glass or fused silica capillary columns. In the second, lipophilic per-n-pentylcyclodextrins and hydrophilic di-n-pentyl- and hydroxyalkylpermethylcyclodextrins are coated directly in the form of liquid phases onto suitably pretreated glass or fused silica surfaces. These techniques permit enantiomer separations not only for polar diols and alcohols, derivatized hydroxycarboxylic acids, amino acids, sugars, and alkyl halides, but also for nonpolar alkenes, cyclic saturated hydrocarbons, and metal π complexes. An important aspect for practical applications is that in many cases the enantiomers can be separated without previous derivatization. Whereas the resolution of racemates of unfunctionalized hydrocarbons is attributed to an enantioselective host–guest inclusion complex, some observations indicate that for polar guest molecules additional enantioselective interactions are also involved. The new chiral stationary phases can be used over a wide range of temperatures (25 to 250°C). The technique described is likely to become widely adopted as a simple, accurate and highly sensitive method for the enantiomeric analysis of chiral compounds that can be vaporized without decomposition. It will also stimulate future research aimed at finding universal cyclodextrin phases and elucidating the mechanisms of enantioselectivity.

373 citations


Journal ArticleDOI
TL;DR: The in vitro experiments explain the changes that occurred in the Pleistocene foraminiferal assemblages from the Red Sea around 18 thousand years ago and earlier and support the conclusion that salinity is the driving mechanism behind this phenomenon.
Abstract: The biological response to extreme temperatures and salinities is investigated in the laboratory for seven species of planktonic foraminifera: Globigerinoides sacculi/er (Brady), Globigerinoides ruber (d'Orbigny), Globigerinoides conglobatus (Brady), Globigerine/la siphonifera (d'Orbigny), Orbulina universa d'Orbigny, Neogloboquadrina dutertrei (d'Orbigny) and Globorotalia menardii (d'Orbigny). When one of the vital processes, food acceptance, growth or reproduction is inhibited by a culture variable, the absolute survival limit is reached. The measured in vitro temperature ranges compare well with the global temperature distribution patterns of these species, suggesting that this parameter plays a major role in their biogeographical distribution. The salinity ranges that are tolerated in laboratory cultures exceed the range encountered in modern oceans. Thus salinity does not limit the distribution of the species investigated herein. In general, larger mean final shell sizes are attained and the total shell length increase is larger at optimum temperatures and salinities than at extreme culture conditions, but the differences were not always statistically significant. Marginal temperature and salinity conditions do not induce contained growth in expatriated specimens. Under extreme culture conditions, the relative frequency of the different shell morphologies is altered relative to normal conditions. "Abnormal" phenotypes are more frequent under normal conditions and the "normal" morphology is found more often under extreme conditions. As opposed to previous reports, the frequency of kummerform chambers generally decreases toward extreme temperature and salinity culture conditions, indicating that kummerform phenotypes are not indicative of environmental stress. The incidence of sac-like chambers in G. sacculi/er and the formation of spherical chambers in adult 0. universa decrease toward extreme temperature and salinity culture conditions, demonstrating that maturation is suppressed in stress situations. SEM investigations show that changes in shell porosity are correlated with treatment variables in culture. The highest porosities are attained at higher temperatures and lower salinities. Generally, an increase in total porosity is achieved by an increase of the pore area accompanied by a reduction of the pore density. The in vitro experiments explain the changes that occurred in the Pleistocene foraminiferal assemblages from the Red Sea around 18 thousand years ago and earlier. During glacial periods, salinity approximated or even exceeded the upper thresholds that were tolerated under laboratory conditions. Under these circumstances, species disappeared from the water column. The order of disappearance as recorded in the sediments may be explained with the upper salinity limits found in this study. Also, the recurrent shifts of dominance between G. sacculi/er and G. ruber are well documented for this fossil assemblage. The present experiments support the conclusion that salinity is the driving mechanism behind this phenomenon. Observations in modern oceans suggest that the fertility of the water mass is probably also an important factor behind the shifts of dominance between G. sacculi/er and G. ruber.

333 citations


Journal ArticleDOI
TL;DR: To determine the time course of intimal and medial SMC proliferation and morphological changes after experimental angioplasty, an intimal atheroma was produced with repeated weak electrical stimulations in the right carotid artery of 45 male New Zealand White rabbits.
Abstract: Smooth muscle cell (SMC) proliferation is known to be an important factor for the development of restenosis after percutaneous transluminal coronary angioplasty To determine the time course of intimal and medial SMC proliferation and morphological changes after experimental angioplasty, an intimal atheroma was produced with repeated weak electrical stimulations in the right carotid artery of 45 male New Zealand White rabbits Angioplasty was subsequently performed in 35 rabbits, and the proliferative responses were analyzed with histomorphological and immunohistological criteria at 3, 7, 14, 21, 28, and 42 days after intervention A hemodynamic relevant stenosis after angioplasty was found in eight (23%) of 35 dilated arteries In five rabbits the stenosis was due to a mural thrombus, and in three animals restenosis was caused by intimal SMC proliferation In all dilated arteries the intimal wall thickness increased from 13 +/- 5 intimal cell layers (after electrical stimulation) to 33 +/- 14 cell layers during 28 days after angioplasty (p less than 005) Later than 4 weeks after angioplasty, no additional increase of intimal thickening occurred Application of bromodeoxyuridine 18 and 12 hours before excision of the vessels allowed determination of the percent of cells undergoing DNA synthesis in the intima and media using monoclonal antibody against bromodeoxyuridine SMCs were identified by alpha-actin staining Immunohistological quantification of intimal SMC proliferation showed a maximum of cells undergoing DNA synthesis within the first 7 days after angioplasty (p less than 001) In contrast, medial proliferation of SMCs was delayed and showed a small but significant increase 21 days after dilatation (p less than 005)(ABSTRACT TRUNCATED AT 250 WORDS)

325 citations


Journal ArticleDOI
TL;DR: The results make it unlikely that the neostriatum is the site of the antiparkinsonian action ofNMDA antagonists in monoamine‐depleted rats, whereas the subthalamic nucleus, internal pallidal segment, and substantia nigra pars reticulata appear to be important for the effects of NMDA antagonists.
Abstract: Systemically administered N-methyl-D-aspartate (NMDA) antagonists, MK-801 ((+)5-methyl-10,11-dihydro-5H-dibenzo(a,d)cyclohepten-5,10-imine maleate) and CPP (3-[(+-)-2-carboxypiperazin-4-yl]-propyl-1-phosphonate), potentiate the ability of L-dopa (L-3,4-dihydroxyphenylalanine) to reverse akinesia and to alleviate muscular rigidity in monoamine-depleted rats. On the basis of these findings, it is proposed that NMDA antagonists may be beneficial as adjunctive treatment in the therapy of Parkinson's disease. CPP locally injected into the subthalamic nucleus, entopeduncular nucleus--the rat homologue of the internal pallidal segment--or substantia nigra pars reticulata of monoamine-depleted rats stimulates locomotor activity and alleviates rigidity, whereas local microinjection of CPP into the neostriatum is ineffective. These results make it unlikely that the neostriatum is the site of the antiparkinsonian action of NMDA antagonists in monoamine-depleted rats, whereas the subthalamic nucleus, internal pallidal segment, and substantia nigra pars reticulata appear to be important for the effects of NMDA antagonists.

306 citations


Journal ArticleDOI
TL;DR: Glycerol-fermenting anaerobes were enriched with glycerol at low and high concentrations in order to obtain strains that produce 1,3-propanediol, and Enterobacterial strains of the genera Enterobacter, Klebsiella, and Citrobacter showed similar product patterns except for one group which formed limited amounts of ethanol, but no propanediol.
Abstract: Glycerol-fermenting anaerobes were enriched with glycerol at low and high concentrations in order to obtain strains that produce 1,3-propanediol. Six isolates were selected for more detailed characterization; four of them were identified as Citrobacter freundii, one as Klebsiella oxytoca and one as K. pneumoniae. The Citrobacter strains formed 1.3-propanediol and acetate and almost no by-products, while the Klebsiella strains produced varying amounts of ethanol in addition and accordingly less 1,3-propanediol. Enterobacterial strains of the genera Enterobacter, Klebsiella, and Citrobacter from culture collections showed similar product patterns except for one group which formed limited amounts of ethanol, but no propanediol. Seven strains were grown in pH-controlled batch cultures to determine the parameters necessary to evaluate their capacity for 1,3-propanediol production. K. pneumoniae DSM 2026 exhibited the highest final concentration (61 g/l) and the best productivity (1.7 g/l h) whereas C. freundii Zu and K2 achieved only 35 g/l and 1.4 g/l h, respectively. The Citrobacter strains on the other hand gave somewhat better yields which were very close to the theoretical optimum of 65 mol %.

293 citations


Journal ArticleDOI
TL;DR: In this paper, the Minimal Group Paradigm: Theoretical Explanations and Empirical Findings is used to explain and empirically find the minimal group paradigm in social psychology.
Abstract: (1990). The Minimal Group Paradigm: Theoretical Explanations and Empirical Findings. European Review of Social Psychology: Vol. 1, European Review of Social Psychology, pp. 263-292.

289 citations


Journal ArticleDOI
TL;DR: It is proposed tentatively that prefrontal dopamine may function to suppress interference during the delay period of certain cognitive tasks.

257 citations


Journal ArticleDOI
TL;DR: By combining the effective ecospace with principles of constructional morphology, an evolutionary flow chart can be modeled that applies to most bivalve groups and it is speculated that some remarkable deviations from this scheme result from endosymbiosis with algae and bacteria that acted as deviators in bivalves evolution.
Abstract: By combining the effective ecospace with principles of constructional morphology, an evolutionary flow chart can be modeled that applies to most bivalve groups. It is speculated that some remarkable deviations from this scheme result from endosymbiosis with algae and bacteria that acted as deviators in bivalve evolution, but may also have increased the probability of their partners to become extinct. Solemyatuba nov. ichnogen. is erected for U‐tubes of presumed Solemya origin.

Journal ArticleDOI
TL;DR: The experiments suggest that sequestration and degradation of normal cytosolic proteins by the autophagic-lysosomal pathway is a nonselective bulk process, and that nonautophagic mechanisms must be invoked to account for differential enzyme turnover.
Abstract: Seven cytosolic enzymes with varying half-lives (ornithine decarboxylase, 0.9 h; tyrosine aminotransferase, 3.1 h; tryptophan oxygenase, 3.3 h; serine dehydratase, 10.3 h; glucokinase, 12.7 h; lactate dehydrogenase, 17.0 h; aldolase, 17.4 h) were found to be autophagically sequestered at the same rate (3.5%/h) in isolated rat hepatocytes. Autophagy was measured as the accumulation of enzyme activity in the sedimentable organelles (mostly lysosomes) of electrodisrupted cells in the presence of the proteinase inhibitor leupeptin. Inhibitors of lysosomal fusion processes (vinblastine and asparagine) allowed accumulation of catalytically active enzyme (in prelysosomal vacuoles) even in the absence of proteolytic inhibition, showing that no inactivation step took place before lysosomal proteolysis. The completeness of protection by leupeptin indicates, furthermore, that a lysosomal cysteine proteinase is obligatorily required for the initial proteolytic attack upon autophagocytosed proteins. The experiments suggest that sequestration and degradation of normal cytosolic proteins by the autophagic-lysosomal pathway is a nonselective bulk process, and that nonautophagic mechanisms must be invoked to account for differential enzyme turnover.

Journal ArticleDOI
TL;DR: With the optimized procedure, other Staphylococcal species such as S. aureus, S. staphylolyticus and S. carnosus were transformed with an efficiency up to 3 X 10(5) transformants per micrograms pC194 plasmid DNA.
Abstract: In this paper, the influence of various parameters on plasmid tranformation by electroporation of Staphylococcus epidermidis Tu3298 was investigated. Cell growth conditions, various concentrations and forms of plasmid DNA, field strength, pulse duration and media for electroporation and regeneration were tested. In order to obtain optimal transformation efficiency, the cells were incubated for 30 min with DNA before pulsing. With the optimized procedure, other staphylococcal species such as S. aureus, S. staphylolyticus and S. carnosus were transformed with an efficiency up to 3× 105 transformants per μg pC194 plasmid DNA.

Journal ArticleDOI
TL;DR: Using proton magnetic resonance analysis on formaldehyde-fixed tissue the stored CTH was identified as globotriaosylceramide and was enzymatically degradable by control cell cultures but left uncleaved by mutant reference Fabry cells.
Abstract: Fabry's disease was diagnosed in an adult patient as a lipid storage-induced non-obstructive hypertrophic cardiomyopathy. Stable angina pectoris started 15 years before death, was followed by slowly progressive heart failure and repeated pulmonary thromboembolism with death at 63 years. Autopsy disclosed enormous cardiomegaly (1100 g), cardiac storage of ceramide trihexoside (CTH) of the same intensity as in classical cases of generalized Fabry's disease (11 mg lipid/g wet weight) restricted to cardiocytes. Other tissues (liver, kidney, brain, pancreas, pulmonary artery, coronary arteries) were free of storage. Using proton magnetic resonance analysis on formaldehyde-fixed tissue the stored CTH was identified as globotriaosylceramide. It was enzymatically degradable by control cell cultures but left uncleaved by mutant reference Fabry cells. Alpha — galactosidase activities in peripheral leucocytes of all four of the patient's daughters were in the heterozygous range. The diagnostic difficulties in this monosymptomatic novel variant of Fabry's disease are stressed.

Journal ArticleDOI
TL;DR: The different relative potencies of tautomycin and okadaic acid for protein phosphatases 1 and 2A suggest that parallel use of both inhibitors may help to identify physiological substrates for each enzyme.

Journal ArticleDOI
TL;DR: It is concluded that interferon gamma is an important lymphokine in the development of psoriasis.
Abstract: • Recombinant human interferon gamma used for treatment of psoriatic arthritis was found to induce expression of HLA-DR, but not HLA-DP or HLA-DQ, on keratinocytes at the site of injection. Some patients showed an improvement of their joint symptoms, but the cutaneous manifestations remained unaffected. In 10 of 42 patients, punctiform psoriatic foci could be induced at the site of injection of interferon gamma. For this presentation, we selected a female patient with psoriatic arthropathy and type II diabetes mellitus in whom psoriasis was induced at the site of application of interferon gamma, but not after subcutaneous injection of insulin or placebo. We conclude that interferon gamma is an important lymphokine in the development of psoriasis. ( Arch Dermatol . 1990;126:351-355)

Book ChapterDOI
TL;DR: In addition to all the biological properties and clinical features of individual patients with acute leukemia, the quality of therapy itself has evolved as the most relevant predictive factor for cure or failure.
Abstract: In addition to all the biological properties and clinical features of individual patients with acute leukemia, the quality of therapy itself has evolved as the most relevant predictive factor for cure or failure. Leukemia is still a life-threatening condition and needs adequate management, irrespective of the phenotypic or genotypic characterization of the leukemic clone.

Journal ArticleDOI
01 Jun 1990-Schmerz
TL;DR: In this paper, a deutsche Fassung des West Haven-Yale Multidimensional Pain Inventory (WHYMPI) wird vorgestellt, die an einer Stichprobe of 185 Schmerzpatienten auf ihre Reliabilitat und Validitat uberpruft wurde.
Abstract: Eine deutsche Fassung des West Haven-Yale Multidimensional Pain Inventory (WHYMPI) wird vorgestellt, die an einer Stichprobe von 185 Schmerzpatienten auf ihre Reliabilitat und Validitat uberpruft wurde. Der Bogen erfast in 12 Skalen psychosoziale Aspekte chronischer Schmerzen: Schmerzstarke, Beeintrachtigung durch den Schmerz, affektive Verstimmung, Lebenskontrolle, soziale Unterstutzung, strafende, zuwendende und ablenkende Reaktionen einer Bezugsperson sowie Aktivitaten im Haus, auser Haus, im sozialen und im Freizeitbereich sowie ein allgemeines Aktivitatsniveau. Der MPI-D erwies sich als intern konsistentes Mas, dessen Faktorenstruktur weitgehend der englischsprachigen entspricht und dessen Unterskalen als valide anzusehen sind. Der Bogen ist daruber hinaus anderungssensitiv, was ihn als Therapieerfolgsmas einsetzbar macht. Im Vergleich zur US-amerikanischen Stichprobe stellten sich die deutschen Patienten als weniger beeintrachtigt dar, was an der spezifischen Stichprobe oder aber an kulturellen Unterschieden liegen mag.

Book ChapterDOI
01 Jan 1990
TL;DR: In the highly eusocial honey bees (Apinae and stingless bees) marked caste syndromes have evolved and the trophogenic basis for caste induction is provided by the nursing workers, although in a colony brood rearing including gyne production is strongly influenced by the queen.
Abstract: In the highly eusocial honey bees (Apinae) and stingless bees (Meliponinae) marked caste syndromes have evolved. The typical queen and worker characteristics are different from one another not just with regard to the reproductive organs but include many other morphological, physiological, and behavioral differences as well. These striking caste distinctions are the result of postembryonic divergences in development which depend on ecological conditions, mainly on the external factor of larval nutrition. Caste development in social insects in general belongs to the widespread phenomena of insect polymorphism and, in accordance with environmental control, castes in bees were called ecomorphs (de Wilde and Wirtz 1974; de Wilde 1975). The trophogenic basis for caste induction is provided by the nursing workers, although in a colony brood rearing including gyne production is strongly influenced by the queen. The queen also rigidly controls all reproduction of the workers. On the other hand, her own reproductive output depends completely on the helper functions of the workers, her daughters.

Journal ArticleDOI
TL;DR: In this article, the clinical records of all patients were analyzed retrospectively, and they were divided into patients with a pure cerebellar syndrome and additional non-cerebellar symptoms.
Abstract: Twenty eight patients with the clinical diagnosis of idiopathic late onset cerebellar ataxia were examined clinically and by magnetic resonance imaging (MRI) or computed tomography (CT). In addition, the clinical records of all patients were analysed retrospectively. On the basis of their clinical presentation they were subdivided into patients with a pure cerebellar syndrome (n = 9) and patients with a cerebellar syndrome and additional non-cerebellar symptoms (n = 13). No attempts were made to classify patients with a disease duration of less than four years (n = 6) because the retrospective analysis showed that the disease started almost invariably with a pure cerebellar syndrome and additional symptoms came later. Patients with a lasting pure cerebellar syndrome had a significantly better prognosis than patients with additional non-cerebellar involvement (annual progression rate rate: 0.40 versus 0.80). Calculated median lifetime from onset of symptoms was 20.7 years in patients with a pure cerebellar syndrome and 7.7 years in patients with additional non-cerebellar symptoms. Among the latter, disease progression was faster the earlier non-cerebellar symptoms occurred. All of them presented with Parkinsonian symptoms, whereas bulbar symptoms, vertical gaze paresis, pyramidal deficits, dementia and urinary incontinence were encountered less frequently. MRI or CT showed cerebellar atrophy without apparent involvement of brainstem structures in all patients with a pure cerebellar syndrome suggesting the diagnosis of cerebellar cortical atrophy (CA). The majority of the patients with additional non-cerebellar symptoms had evidence of an atrophy of the cerebellum and the brainstem suggesting the presence of olivo-ponto-cerebellar atrophy (OPCA). In two of them, however, MRI morphology was not compatible with the diagnosis of OPCA.

Journal ArticleDOI
TL;DR: It has been possible to demonstrate that the character of the inflammatory interstitial changes that accompany glomerular diseases is always the same, no matter what the glomerulopathy may be.
Abstract: In recent years it has become recognized to an increasing extent that a wide range of inflammatory and non-inflammatory glomerular diseases may be complicated with varying frequency by disease in the region of the post-glomerular intertubular capillaries Thus we found additional disease of the tubulo-interstitial system in 40 – 695% of patients with the diseases listed in Table 1 Amongst these diseases, accompanying inflammation of the renal cortical interstitium occurs least often in endocapillary glomerulonephritis and most often in diabetic glomerulosclerosis Amongst the glomerulonephritides, interstitial inflammation leading to fibrosis is observed most frequently in rapidly progressive glomerulonephritis and membranoproliferative glomerulonephritis Interstitial inflammation is found relatively often in glomerular amyloidosis As a result of investigations we have undertaken in the last three years, it has been possible to demonstrate that the character of the inflammatory interstitial changes that accompany glomerular diseases is always the same, no matter what the glomerulopathy may be The cells most predominantly involved in the inflammatory process are T lymphocytes, macrophages, fibroblasts and fibrocytes Thus dense foci of T lymphocytes and macrophages are seen not only in Table 1 Survey of the incidence of intertubular inflammation associated with interstitial fibrosis in various glomerulopathies Various Glomerulopathies And The Occurrence Of Interstitial Inflammation And Interstitial Fibrosis Total Number Of Casas Cases With Interstitial Fibrosis (%) 1) Endocapillary GN 137 40 2) Minimal Changes With NS 470 85 3) Focal Sclerosing GN 469 341 4) Mesangioproliferative GN 805 230 a) Immunologically Negative GN 238 139 b) IgA Nephritis 369 233 c) Non-lgA Nephritis 198 333 5) Chronic Idiopathic Membranous GN 642 238 6) Membranoproliferative GN Type I 259 410 7) Rapidly Progressive GN 208 567 8) Perireticular Amyloidosis 443 480 9) Diabetic Glomerulosclerosis 406 695 mesangioproliferative glomerulonephritis, but also in the interstitial inflammation that complicates renal amyloidosis The tubulo-interstitial inflammation of diabetic glomerulosclerosis is also characterized by T lymphocytes, macrophages, fibroblasts and fibrocytes


Journal ArticleDOI
TL;DR: DL-[5-14C]ornithine was incorporated into staphyloferrin A, demonstrating that ornithine is an intermediate in staphylloferrIn A biosynthesis.
Abstract: Two ferric ion-binding compounds, designated staphyloferrin A and B, were detected in the culture filtrates of staphylococci grown under iron-deficient conditions. Staphyloferrin A was isolated from cultures of Staphylococcus hyicus DSM 20459. The structural elucidation of this highly hydrophilic, acid-labile compound revealed a novel siderophore, N2,N5-di-(1-oxo-3-hydroxy-3,4-dicarboxybutyl)-D-ornithine, which consists of one ornithine and two citric acid residues linked by two amide bonds. The two citric acid components of staphyloferrin A provide two tridentate pendant ligands, comprising of a beta-hydroxy, beta-carboxy-substituted carboxylic acid derivative, for octahedral metal chelation. The CD spectrum of the staphyloferrin A ferric complex indicates a predominant A configuration about the ferric ion center. The uptake of ferric staphyloferrin A by S. hyicus obeys Michaelis-Menten kinetics (Km = 0.246 microM; vmax = 82 pmol.mg-1.min-1), indicating active transport of this siderophore. The staphyloferrin A transport system is different from that of the ferrioxamines as shown by an antagonism test. Production of staphyloferrin A is strongly iron-dependent and is stimulated by supplementation of the medium with either D- or L-ornithine. DL-[5-14C]ornithine was incorporated into staphyloferrin A, demonstrating that ornithine is an intermediate in staphyloferrin A biosynthesis.

Journal ArticleDOI
TL;DR: In this article, a dynamic psychobiological model of chronic pain is proposed, which integrates both biomedical and psychological variables in the etiology, maintenance, and exacerbation of the chronic pain.

Journal ArticleDOI
TL;DR: The experimental gingivitis model was used to compare the anti-plaque, anti-gingivitis and anti-microbial efficacies of a phenolic compound (Listerine) and an amine/stannous fluoride mouthwash (Meridol), using a placebo preparation as negative control and a chlorhexidine solution as positive control in a double-blind study as mentioned in this paper.
Abstract: The experimental gingivitis model was used to compare the anti-plaque, anti-gingivitis and anti-microbial efficacies of a phenolic compound (Listerine) and an amine/stannous fluoride mouthwash (Meridol), using a placebo preparation as negative control and a chlorhexidine solution as positive control in a double-blind study. After professional toothcleaning, 36 volunteers performed optimal oral hygiene for a period of 2 weeks. They then ceased all oral hygiene procedures for 21 days during which they rinsed twice daily with 1 of the 4 mouthrinses. After 3 weeks of rinsing, plaque indices remained the lowest in the chlorhexidine group, while subjects using Listerine or Meridol harbored similar indices significantly lower than that of individuals rinsing with the placebo solution. Up to that time, the gingival index scores were equal in all groups except for the chlorhexidine group in which the values only amounted to half of these encountered in the other groups. The plaque vitality scores showed a bactericidal effect in vivo of chlorhexidine during the entire time of experimental gingivitis. In contrast, the data gave no evidence of an antibacterial effect in vivo of Listerine. The efficacy of Meridol to kill micro-organisms was similar to chlorhexidine during the early stages of plaque accumulation and, with time, became insignificant. This study has demonstrated that chlorhexidine was superior to Listerine and Meridol in its ability to maintain low plaque scores and gingival health during this 3-week period of no mechanical oral hygiene. Moreover, it was also shown that Meridol was as effective as Listerine in reducing plaque accumulation and, in contrast to Listerine, possessed a remarkable but transient antibacterial effect in vivo.

Journal ArticleDOI
TL;DR: The cloned sfu region of the Serratia marcescens chromosome confers the ability to grow on iron-limited media to an Escherichia coli K-12 strain that is unable to synthesize a siderophore.
Abstract: The cloned sfu region of the Serratia marcescens chromosome confers the ability to grow on iron-limited media to an Escherichia coli K-12 strain that is unable to synthesize a siderophore. This DNA fragment was sequenced and found to contain three genes termed sfuA, sfuB, and sfuC, arranged and transcribed in that order. The sfuA gene encoded a periplasmic polypeptide with calculated molecular weights of 36,154 for the precursor and 33,490 for the mature protein. The sfuB gene product was a very hydrophobic protein with a molecular weight of 56,589. The sfuC gene was found to encode a rather polar but membrane-bound protein with a molecular weight of 36,671 which exhibited strong homology to consensus sequences of nucleotide-binding proteins. The number, structural characteristics, and locations of the SfuABC proteins were typical of a periplasmic-binding-protein-dependent transport mechanism. How Fe3+ is solubilized and taken up across the outer membrane remains an enigma.

Journal ArticleDOI
TL;DR: Dihydroxybenzoylserine, the breakdown product of enterochelin, was able to stimulate growth of Escherichia coli under iron limiting conditions by acting as a siderophore and it was shown that dihydroxybenzoate was taken up via Fiu and Cir and less efficiently by FepA.
Abstract: Dihydroxybenzoylserine, the breakdown product of enterochelin, was able to stimulate growth of Escherichia coli under iron limiting conditions by acting as a siderophore. The dihydroxybenzoylserine-iron complex was taken up via the outer membrane receptor proteins Fiu, FepA and to a minor extent via Cir. Transport fo Fe3+-dihydroxybenzoylserine across the cytoplasmic membrane was only dependent on genes from the fep region. In addition, it was shown that dihydroxybenzoate was taken up via Fiu and Cir and less efficiently by FepA.

Book ChapterDOI
01 Jan 1990
TL;DR: In this paper, the synthesis of porphyrins and phthalocyanines using macrocycles has been described, and the different ways to use the macrocycles for the mentioned properties.
Abstract: Phthalocyanines and related complexes are important compounds due to their special electrical and optical properties. This article describes, after a more preparative part on the synthesis of porphyrins and phthalocyanines, the different ways to use the macrocycles for the mentioned properties.


Journal Article
TL;DR: Multivariate survivorship analysis showed that tubulointerstitial changes and the presence of nephrotic syndrome at the time of biopsy are the only variables with significant independent predictive value for the outcome.
Abstract: The following results were obtained in a long-term retrospective study including 250 patients with focal sclerosing glomerulonephritis: 1. The renal survival rate (RSR) was 90% at 5 years and 67% at 10 years, the average period of observation being 4.7 years. 2. Univariate analysis revealed that the following morphologic and clinical parameters are associated with an increased risk of terminal renal failure or death due to renal causes: a) Tubulointerstitial changes in the form of interstitial fibrosis, with or without acute renal failure; b) Advanced glomerular lesions; c) Advanced vascular alterations; d) Nephrotic syndrome present at the time of the biopsy; e) Elevated serum creatinine concentration at the time of the biopsy; f) Arterial hypertension at the time of the biopsy; g) Greater age at diagnosis; h) Male sex. 3. Multivariate survivorship analysis showed that tubulointerstitial changes and the presence of nephrotic syndrome at the time of biopsy are the only variables with significant independent predictive value for the outcome. Assessment of these factors thus allows the pathologist to make a relevant statement concerning the probable course and prognosis of the disease at the time of the diagnostic biopsy.