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Biomedical subjects

R Bauer

Publications and source records attributed to R Bauer.

At least 55 records · Page 3Linked to original sources
PubMed2002

Intrauterine growth restriction reduces nephron number and renal excretory function in newborn piglets.

To examine the effects of intrauterine growth restriction on nephron number, renal circulation, and renal excretory functions in newborns, studies were conducted on 1-day-old anaesthetized piglets, divided into normal weight (n = 6) and intrauterine growth restricted (n = 6) piglets. Renal blood flow was measured by coloured microspheres, glomerular filtration rate was measured by inulin clearance, and osmotic clearance and fractional sodium excretion were calculated. In addition, an estimation of the nephron number was performed by counting representative glomerular numbers in microscopic sections. Newborn intrauterine growth restricted piglets exhibited a reduced glomerular filtration rate and osmotic clearance (P < 0.05), whereas renal blood flow and the filtration fraction as well as fractional sodium excretion were similar in normal weight and intrauterine growth restricted piglets. The nephron number was markedly reduced in intrauterine growth restricted piglets even if the nephron number was related to body weight (P < 0.01). There was a positive correlation between nephron number and glomerular filtration rate (r = 0.69, P < 0.05). Reduced glomerular filtration rate of newborn intrauterine growth restricted piglets is associated with a reduced nephron number. Thus, at birth, compensatory response of renal function due to nephron deficit does not exist in intrauterine growth restricted piglets.

Animals↗
PubMed2002

The value of lymphocytopenia as a marker of systemic involvement in cutaneous lupus erythematosus.

BACKGROUND: Some patients suffering from cutaneous lupus erythematosus (CLE) develop extracutaneous manifestations during the course of the disease: up to 5% of patients with discoid LE (DLE) and up to 30% of subacute cutaneous LE (SCLE) patients show systemic involvement. Recent studies revealed some markers indicating systemic manifestations of CLE patients. However, the significance of diminished peripheral lymphocyte numbers as a marker of systemic involvement in CLE has not been investigated before. OBJECTIVES: To determine the value of lymphocytopenia (< 1500 cells microL(-1)) as a marker of extracutaneous manifestations in CLE patients. : Methods The records of 72 CLE patients (44 DLE; 28 SCLE) were investigated. Systemic involvement was defined in accordance with the criteria of the European Academy of Dermatology and Venereology. Analyses of peripheral lymphocyte numbers were done by fluorescence-activated cell sorter analysis. RESULTS: Five CLE patients developed extracutaneous manifestations during the course of disease. All these patients were lymphocytopenic. Differences between peripheral lymphocyte numbers of CLE patients with and without additional systemic involvement were highly significant (P < 0.01). CONCLUSIONS: Our results suggest that lymphocytopenia in patients with CLE is a high sensitive but low specific marker of systemic involvement.

Adult↗
PubMed2002

[New knowledge regarding the effect and effectiveness of Echinacea purpurea extracts].

Preparations made from the pressed juice of the flowering aerial parts of the Purple Coneflower, Echinacea purpurea (L.) Moench represent the most commonly used herbal immunnomodulatory agents. They are frequently administered for the supportive treatment of common viral infections of the upper respiratory tract. New clinical studies are reviewed, which demonstrated that corresponding preparations can diminish the severity and the length of common colds significantly, and that they can also be used efficiently for the treatment of children. New investigations have also shown, that stimulation of makrophages and induction of cytokins are major parts of the mode of action, and that glycoproteins/polysaccharides and alkamides are part of the activity relevant constituents.

Adjuvants, Immunologic↗
PubMed2002

Transport of alkamides from Echinacea species through Caco-2 monolayers.

To gain more insights into the human intestinal absorption of alkamides from Echinacea species, transport studies were performed with the human adenocarcinoma colonic cell line Caco-2 (ATCC) as a model to assess the epithelial transport of dodeca-2 E,4 E,8 Z,10 E/ Z-tetraenoic acid isobutylamides (1/ 2). 30 minutes after apical loading of 25 microg/ml 1/ 2, about 15 % of these alkamides were detectable on the basolateral side. Close monitoring of the transport during 6 hours revealed a nearly complete transport to the basolateral side after 4 hours and no significant metabolism was observable. Transport experiments performed at 4 degrees C showed only a slight decrease in transport, which is a strong hint that dodeca-2 E,4 E,8 Z,10 E/ Z-tetraenoic acid isobutylamides (1/ 2) cross biological membranes by passive diffusion. Nearly the same results were obtained after preincubation of the Caco-2 cells with lipopolysaccharides (LPS) or phorbol 12-myristate-13-acetate (PMA) to mimic an inflammatory status. These results support the assumption that the alkamides can be easily transported from the intestinum and hence may contribute to the in vivo effects of Echinacea preparations.

Biological Transport↗
PubMed2002

Effects of tenuiorin and methyl orsellinate from the lichen Peltigera leucophlebia on 5-/15-lipoxygenases and proliferation of malignant cell lines in vitro.

The orcinol derivatives tenuiorin (1) and methyl orsellinate (2) were identified as active components of an extract from the lichen Peltigera leucophlebia (Nyl.) Gyeln. showing in vitro inhibitory activity against 15-lipoxygenase from soybeans. The compounds were subsequently tested for in vitro activity against 5-lipoxygenase from porcine leucocytes and proved to be moderately active, with IC50 values of 41.6 microM and 59.6 microM respectively. Tenuiorin is a known constituent of several Peltigera species but has not previously been isolated from P. leucophlebia. As correlation between 5-lipoxygenase inhibition and antiproliferative effects has earlier been witnessed for related lichen metabolites, tenuiorin and methyl orsellinate were further tested for antiproliferative activity on cultured human breast (T-47D)-, pancreatic (PANC-1)- and colon (WIDR) cancer cell lines. The monomeric methyl orsellinate exhibited no detectable antiproliferative activity whereas the trimeric tenuiorin caused moderate/weak reduction in [3H]-thymidine uptake of the pancreatic- and colon cancer cells, with ED50 values of 87.9 and 98.3 microM respectively.

Breast Neoplasms↗
PubMed2002

Radioiodine treatment of feline hyperthyroidism in Germany.

AIM: Establishment of radioiodine treatment of feline hyperthyroidism in veterinary routine in accordance with German radiation protection regulations. PATIENTS AND METHODS: 35 cats with proven hyperthyroidism were treated with 131I in a special ward. Thyroid uptake and effective halflife were determined using gammacamera dosimetry. Patients were released when measured whole body activity was below the limit defined in the German "Strahlenschutzverordnung". RESULTS: 17/20 cats treated with 150 MBq radioiodine and 15/15 cats treated with 250 MBq had normal thyroid function after therapy, normal values for FT3 and FT4 were reached after two and normal TSH levels after three weeks. In 14 cats normal thyroid function was confirmed by controls 3-6 months later. Thyroidal iodine uptake was 24 +/- 10%, effective halflife 2.5 +/- 0.7 days. Whole body activity < 1 MBq was reached 13 +/- 4 days after application of 131I. Radiation exposure of cat owners was estimated as 1.97 microSv/MBq for adults. CONCLUSION: Radioiodine therapy of feline hyperthyroidism is highly effective and safe. It can easily be performed in accordance with German radiation protection regulations, although this requires hospitalisation for approximately two weeks. Practical considerations on radiation exposure of cat owners do not justify this long interval. Regulations for the veterinary use of radioactive substances similar to existing regulations for medical use in humans are highly desirable.

Adult↗
PubMed2002

MMPI-2 profiles of patients with intractable epilepsy.

MMPI-2 profiles of 93 presurgical intractable epilepsy patients were examined using Ward's method of cluster analysis. Three clusters were identified. The means of each cluster suggest that 45% of the sample had minimal psychological complaints, 30% presented with generalized clinical elevations, and 25% of the patients had profiles of intermediate elevations with a tendency to emphasize somatic complaints and/or depression. Gender, age of seizure onset, and seizure laterality were not found to be uniquely associated with the cluster profiles. Further examination of correlates of group membership is warranted to provide information for treatment planning.

Journal Article↗
PubMed2001

Dynamics of mononuclear cadmium beta-lactamase revealed by the combination of NMR and PAC spectroscopy.

The two metal sites in cadmium substituted beta-lactamase from Bacillus cereus 569/H/9 have been studied by NMR spectroscopy ((1)H, (15)N, and (113)Cd) and PAC spectroscopy ((111m)Cd). Distinct NMR signals from the backbone amides are identified for the apoenzyme and the mononuclear and binuclear cadmium enzymes. For the binuclear cadmium enzyme, two (113)Cd NMR signals (142 and 262 ppm) and two (111m)Cd PAC nuclear quadrupole interactions are observed. Two nuclear quadrupole interactions are also observed, with approximately equal occupancy, in the PAC spectra at cadmium/enzyme ratios < 1; these are different from those derived for the binuclear cadmium enzyme, demonstrating interaction between the two metal ion binding sites. In contrast to the observation from PAC spectroscopy, only one (113)Cd NMR signal (176 ppm) is observed at cadmium/enzyme ratios < 1. The titration of the metal site imidazole (N)H proton signals as a function of cadmium ion-to-enzyme ratio shows that signals characteristic for the binuclear cadmium enzyme appear when the cadmium ion-to-enzyme ratio is between 1 and 2, whereas no signals are observed at stoichiometries less than 1. The simplest explanation consistent with all data is that, at cadmium/enzyme ratios < 1, the single Cd(II) is undergoing exchange between the two metal sites on the enzyme. This exchange must be fast on the (113)Cd NMR time scale and slow on the (111m)Cd PAC time scale and must thus occur in a time regime between 0.1 and 10 micros.

Bacillus cereus↗
PubMed2001

Metal ion binding and coordination geometry for wild type and mutants of metallo-beta -lactamase from Bacillus cereus 569/H/9 (BcII): a combined thermodynamic, kinetic, and spectroscopic approach.

One high affinity (nm) and one low affinity (microM) macroscopic dissociation constant for the binding of metal ions were found for the wild-type metallo-beta-lactamase from Bacillus cereus as well as six single-site mutants in which all ligands in the two metal binding sites were altered. Surprisingly, the mutations did not cause a specific alteration of the affinity of metal ions for the sole modified binding site as determined by extended x-ray absorption fine structure (EXAFS) and perturbed angular correlation of gamma-rays spectroscopy, respectively. Also UV-visible absorption spectra for the mono-cobalt enzymes clearly contain contributions from both metal sites. The observations of the very similar microscopic dissociation constants of both binding sites in contrast to the significantly differing macroscopic dissociation constants inevitably led to the conclusion that binding to the two metal sites exhibits negative cooperativity. The slow association rates for forming the binuclear enzyme determined by stopped-flow fluorescence measurements suggested that fast metal exchange between the two sites for the mononuclear enzyme hinders the binding of a second metal ion. EXAFS spectroscopy of the mono- and di-zinc wild type enzymes and two di-zinc mutants provide a definition of the metal ion environments, which is compared with the available x-ray crystallographic data.

Bacillus cereus↗
PubMed2001

Alignment delays in the N = Z nuclei (72)Kr, (76)Sr, and (80)Zr.

The ground state rotational bands of the N = Z nuclei (72)Kr, (76)Sr, and (80)Zr have been extended into the angular momentum region where rotation alignment of particles is normally expected. By measuring the moments of inertia of these bands we have observed a consistent increase in the rotational frequency required to start pair breaking, when compared to neighboring nuclei. (72)Kr shows the most marked effect. It has been widely suggested that these "delayed alignments" arise from np-pairing correlations. However, alignment frequencies are very sensitive to shape degrees of freedom and normal pairing, so the new experimental observations are still open to interpretation.

Journal Article↗
PubMed2001

Polyphenylene dendrimers with different fluorescent chromophores asymmetrically distributed at the periphery.

A new synthetic approach leading to asymmetrically substituted polyphenylene dendrimers is presented. Following this method, polyphenylene dendrimers decorated with an increasing number of chromophores at the periphery have been obtained up to the second generation. Especially the synthesis of a polyphenylene dendrimer bearing three donor chromophores and one acceptor chromophore has been realized. Intramolecular energy transfer within this molecule is demonstrated by applying absorption and fluorescence measurements.

Journal Article↗
PubMed2001

Amylopectin aggregation as a function of starch phosphate content studied by size exclusion chromatography and on-line refractive index and light scattering.

Starches with a natural 65-fold span in covalently bound phosphate content were prepared from five different crops including sorghum, cassava, three potato varieties and an exotic ginger plant, Curcuma zedoaria, with extreme starch phosphate content. These starches were subjected to size exclusion chromatography with refractive index detection (SEC/RI). A simple and rapid method for starch solubilisation was used. The conditions during solubilisation (2 M NaOH) and separation (10 mM NaOH, 50 degrees C) were such as enabling > 94% recovery of the starch without detectable degradation. The aggregation properties of the starch was investigated using on line refractive index/multi angle laser light scattering (RI/MALLS) detection. Three major regions in the SEC profile were identified, consisting of large amylopectin aggregates, amylopectin particles with radius of gyration (Rg) of approx 200 nm (400 nm blocklets) and amylose. A procedure for correction of light scattering signals spread over the SEC profile as a result of aggregate tailing was developed. The significance of the relative amounts of these three molecular species on standard starch pasting parameters, as measured by a Rapid Visco Analyzer (RVA), was investigated. Starches with a high amount of amylopectin aggregates showed high peak viscosities. Moreover, very high amounts of starch bound phosphate or amylose appears to suppress the content of large aggregates resulting in low viscosity.

Amylopectin↗
PubMed2001

Immunomorphological sequelae of severe brain injury induced by fluid-percussion in juvenile pigs--effects of mild hypothermia.

Severe traumatic brain injury (TBI) often leads to a bad outcome with considerable neurological deficits. Secondary brain injuries due to a rise of intracranial pressure (ICP) and global hypoxia-ischemia are critical and may be reduced in extent by mild hypothermia. A porcine animal model was used to study the effect of severe TBI, induced by fluid percussion (FP; 3.5+/-0.3 atm) in combination with a secondary insult, i.e., temporary blood loss with hypovolemic hypotension. Six-week-old juvenile pigs were subjected to this kind of severe TBI; one group was then submitted to moderate hypothermia at 32 degrees C for 6 h, starting 1 h after brain injury. Animals were killed after 24 h. TBI and hypothermia-associated alterations in the brains were investigated by immunohistochemistry with antibodies against microtubule-associated protein 2 (MAP-2) and beta-amyloid precursor protein (betaAPP). In addition, DNA fragmentation was investigated by the terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) method. Seven of the 13 normothermic TBI animals developed a secondary increase in ICP (TBI-NT-ICP) after an interval of several hours. None of the animals in the hypothermic trauma (TBI-HT) group exhibited a secondary ICP increase, indicating a protective effect of the treatment. TBI-HT animals showed significantly higher levels of MAP-2 immunoreactivity, lower levels of betaAPP immunoreactivity and less DNA fragmentation than the TBI-NT-ICP animals. Differences between the TBI-HT group and normothermic animals without an ICP increase (TBI-NT) were less marked. A considerable decrease in MAP-2 outside the site of TBI-FP administration was seen only in the TBI-NT-ICP animals. MAP-2 immunohistochemistry was thus a reliable marker of diffuse brain damage. Axonal injury was present in all TBI groups, indicating its special significance in neurotrauma. Thus, severe TBI caused by FP, combined with temporary blood loss, consistently produced traumatic axonal injury and focal brain damage. Mild hypothermia was able to prevent a secondary increase in ICP and its sequelae of diffuse hypoxic-ischemic brain injury. However, hypothermia did not afford protection from traumatic axonal injury.

Age Factors↗
PubMed2001

Constituents of Chinese Piper species and their inhibitory activity on prostaglandin and leukotriene biosynthesis in vitro.

The n-hexane extracts of 19 Piper species, predominantly from China, were screened for their 5-lipoxygenase (5-LOX) and cyclooxygenase-1 (COX-1) inhibitory potential. Many of them showed considerable inhibitory activity against at least one of these two key enzymes of the arachidonic acid metabolism, especially against COX-1. The best results in inhibiting the formation of leukotrienes were obtained with the extract of Piper kadsura. In the terms of prostaglandin synthesis inhibition, the extract of Piper boehmeriifolium var. tonkinense was found to have the strongest activity. Furthermore, an analytical investigation by means of TLC, HPLC-DAD and GC-MS resulted in the identification of 20 constituents. Most of them were amides with an interesting variety of amine moieties. Among them were pellitorine, and four higher homologues, piperlonguminine, dihydropiperlonguminine, futoamide, chingchengenamide, the retrofractamides A, B and D, guineensine, brachystamide B, piperanine, piperine, piperdardine, sarmentine, pipataline and benzylbenzoate. In 96 cases, these constituents were new for the particular plant.

Animals↗
PubMed2001

Control of endoreduplication domains in the Drosophila gut by the knirps and knirps-related genes.

Endoreduplication cycles that lead to an increase of DNA ploidy and cell size occur in distinct spatial and temporal patterns during Drosophila development. Only little is known about the regulation of these modified cell cycles. We have investigated fore- and hindgut development and we present evidence that the Drosophila knirps and knirps-related genes are key components to spatially restrict endoreduplication domains. Our lack and gain-of-function experiments show that knirps and knirps-related which encode nuclear orphan receptors transcriptionally repress S-phase genes of the cell cycle required for DNA replication and that this down-regulation is crucial for gut morphogenesis. Furthermore, we demonstrate that both genes are activated in overlapping expression domains in the fore- and hindgut in response to Wingless and Hedgehog activities emanating from epithelial signaling centers that control the regionalization of the gut tube. Our results provide a novel link between morphogen-dependent positional information and the spatio-temporal regulation of cell cycle activity in the gut.

Animals↗
PubMed2001

Induction of sTNF-R1 and sTNF-R2 by interferon beta-1b in correlation with clinical and MRI activity.

OBJECTIVES: To investigate the influence of interferon (IFN) beta-1b on the serum levels of sTNF-R1, sTNF-R2 and TNF-beta in patients with multiple sclerosis (MS) in correlation with clinical and MRI activity. MATERIALS AND METHODS: Serum samples were obtained every 3 months from 24 patients treated with 8 x 10(6) U of IFN beta-lb every other day (treatment group) and from 21 patients without any immunomodulatory therapy (control group) over a 15-month observation period. The cytokine levels were measured by ELISA. Cranial MRI was performed every 6 months to determine the burden of disease of every patient. RESULTS: In the treatment group we found an obvious increase of sTNFR1 and sTNF-R2 (P < 0.001) and relatively stable serum levels of TNFbeta with no statistical significance (P = 0.56). In the control group, sTNF-R1 showed a significant decrease (P < 0.001) during the same observation period of 15 months. During the 15-month observation period, the MRI-responders group had significant larger mean AUC (area under the concentration-time curve) values of sTNF-R1 (P = 0.04) and sTNF-R2 (P = 0.01) when compared to the group of MRInonresponders. CONCLUSION: The present data suggest that IFN beta-1b induces the expression and shedding of TNF-R1 and TNF-R2. The magnitude of an increase of sTNF-Rs may be a marker for the effectiveness of treatment with IFN beta-1b.

Adjuvants, Immunologic↗