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Biomedical subjects

R Kaufmann

Publications and source records attributed to R Kaufmann.

At least 19 recordsLinked to original sources
PubMed1997

IgG-antibodies to CNS proteins in patients with multiple sclerosis.

The CSF and sera of 185 patients with multiple sclerosis (MS), 130 patients with other inflammatory diseases of the CNS (OID) and 50 patients with spinal disc syndrome (controls) were investigated for IgG-antibodies to CNS proteins by SDS-PAGE and immunoblotting and by isoelectric focusing combined with affinity blotting. IgG-antibodies to CNS proteins in serum (immunoblotting) were detected in 18 patients with MS (10%), in 29 patients with OID (22%) and in four controls (8%). Intrathecal synthesis of IgG-antibodies to CNS proteins was demonstrated in 11 patients with MS (6%), in 37 patients with OID (28%) and in none of the controls. In 4/11 patients with MS intrathecally produced antibodies were shown to be specific for glial fibrillary acidic protein (GFAP). Of patients with MS, 180 displayed oligoclonal IgG-bands in the CSF. Specificity of these bands for CNS proteins was demonstrated only in 2/180 specimens (1%). These findings indicate, that in most patients with MS oligoclonal IgG-bands in the CSF do not contain relevant amounts of antibodies to CNS proteins.

Enzyme-Linked Immunosorbent Assay↗
PubMed1997

A new glycosylated lipopeptide incorporated into the cell wall of a smooth variant of Gordona hydrophobica.

A cell wall component of a smooth variant of Gordona hydrophobica 1775/15 was isolated and purified, and its structure was determined by various chemical methods, including chemical synthesis of part structures, Edman degradation, gas chromatography/mass spectrometry analysis, matrix-assisted laser desorption ionization-post-source decay (MALDI-PSD) tandem mass spectrometry, and 1H and 13C NMR using one- and two-dimensional, homo- and heteronuclear correlated spectroscopy. The cell wall component was found to be a (mono-) glycosylated peptidolipid (GPL) consisting of a tridecapeptide interlinked by a beta-hydroxylated fatty acid (3-hydroxyeicosanoic acid, 20:0 (3-OH)) to form a cyclic lactone ring structure. The main fraction of GPL, for which we propose the name gordonin, was identified as 3-hydroxyeicosanoyl-L-seryl-L-phenylalanyl-L-seryl- L-seryl-D-alanyl-L -(O-beta-D-glucopyranosyl)-threonyl-glycyl-D-leucyl-L-valyl-L-seryl-L -phenylalanyl-glycyl-L-valyl lactone. The other GPLs constitute structural variations within the nature of the beta-hydroxylated fatty acid (20:0(3-OH) versus 22:1(3-OH)) in a ratio of about 1:0.9 as well as within one amino acid (D-Leu versus L-Phe) in about 30%. Sequence information was obtained in part by Edman degradation as well as gas chromatography/mass spectrometry analysis of di- and tripeptide fragments. However, the complete amino acid sequence could only be established by MALDI-PSD from the linear molecule, i.e. after ring opening of the lactone. In contrast, rough variants of G. hydrophobica 1775/15 lack these peptidolipids or synthesize them to a much lesser extent indicating that gordonin contributes significantly to the physicochemical character of the cell surface.

Actinomycetales↗
PubMed1997

Identification of endogenous Des-Arg9-[Hyp3]-bradykinin in human plasma with post-source-decay matrix-assisted laser desorption/ionization mass spectrometry.

In the present study, the purification and sequence analysis of a peptide extracted from human plasma is described. After three chromatographic steps in one of the plasma fractions, a molecular mass of 920 Da was determined with matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analysis. Further analysis with post-source-decay (PSD)-MALDI-MS revealed an amino acid sequence arg-pro(pro-gly+16)-phe-ser-pro-phe. With the data given from the spectrum, it was impossible to clarify the partial sequence (pro-gly+16). A comparison with a data base suggested that the sequence is very similar to des-arg9bradykinin (arg-pro-pro-gly-phe-ser-pro-phe). But many fragment masses, including the mass of the parent ion of the unknown peptide, are 16 Da larger than the corresponding fragment masses of des-arg9-bradykinin. The interpretation of the fragment pattern does not allow determination of the position of the amino acid that is 16 Da larger. With automated Edman sequence analysis of the fraction of interest, three more major component peptides in this fraction were observed, which were not detected with MALDI-MS. Nevertheless, with the help of the Edman sequence data it was possible to identify the unknown amino acid in the PSD-MALDI-MS sequence as hydroxyproline at the third position. In conclusion, the existence of des-arg9[hyp3]-bradykinin (arg-pro-hyp-gly-phe-ser-pro-phe) in human plasma is described. Furthermore, the study demonstrates that PSD-MALDI-MS and automated Edman sequence analysis complement each other if single unknown peptides from mixtures are to be sequenced.

Bradykinin↗
PubMed1997

Isolation and structural elucidation of two pyrokinins from the retrocerebral complex of the American cockroach.

By monitoring the contractile activity of the hyperneural muscle of the American cockroach in vitro two peptides were isolated from the retrocerebral complex of the American cockroach. Three purification steps using reversed-phase high performance liquid chromatography on C-18 columns containing trifluoroacetic acid or heptafluorobutyric acid as organic modifiers were sufficient to achieve homogeneous peptide preparations. The structures of both peptides were elucidated by a combination of Edman degradation and mass spectrometry which yielded the following structures: His-Thr-Ala-Gly Phe-Ile-Pro-Arg-Leu-NH2 (Pea-PK-1) and Ser-Pro-Pro-Phe-Ala-Pro-Arg-Leu-NH2 (Pea-PK-2). The C-terminal sequence Phe-X-Pro-Arg-Leu-NH2 characterized the peptides as members of the insect pyrokinin family. The synthetic peptides were shown to have the same retention times as the natural peptides. The occurrence of both peptides in the retrocerebral complex suggests a physiological role as neurohormones. The effects of the synthetic pyrokinis were clearly distinguishable in their actions on the hyperneural muscle. Regarding the threshold concentrations, Pea-PK-2 was only 0.3% as active as Pea-PK-1.

Amino Acid Sequence↗
PubMed1997

Subcutaneously pedicled island flaps.

Subcutaneously pedicled island flaps (SPIF) are very mobile local flaps bringing into the surgical defect skin of similar texture and color to that of the recipient site. SPIF flaps are eminently simple to create: an island of skin is incised until the fatty tissue is visualized and the flap connections to surrounding tissue are carefully disconnected without damaging the nutrient vessels. The viability of such flaps is excellent. If appropriately performed, side effects such as pincushioning are rare.

Esthetics↗
PubMed1997

The implantable fuzzy controlled Helmholtz-left ventricular assist device: first in vitro testing.

To perform first experimental tests for validation of a new left ventricular assist device (LVAD) with a high efficiency energy converter, a new pump design and a novel type of perfusion control, a functional labtype, were manufactured. With a stroke volume of 65 ml, a total pump housing volume of 450 ml (including valves and connectors), and a weight of 430 g, it is one of the smallest and lightest implantable pulsatile electromechanical LVADs. Pulsatile operation is generated by a special reduction and displacement gear which transforms a uniform rotational movement of a sensorless, electronically commutated DC motor into a translatory pusher plate movement. A prolonged duration for filling (60% of the cycle time) supports full-empty pumping and consequently a high overall pump efficiency. Active adaptation of output flow to organ perfusion demand is achieved by changing the rotational speed of the motor by means of a sensorless fuzzy controller, which detects preload and afterload induced effects at the motor current input. First in vitro test results obtained within a circulatory mock loop that simulates physiological preloads and afterloads are presented. They comprise preload sensitivity and the function of the novel perfusion controller as well as preload and afterload related flow data. The results prove the feasability of the energy conversion with the novel gear and control concept for an implantable electromechanical pulsatile LVAD.

Animals↗
PubMed1997

Induction of psoriasiform inflammation by a bacterial superantigen in the SCID-hu xenogeneic transplantation model.

Psoriasis is a chronic skin disease affecting about 2% of the Caucasian population, characterized by co-existing inflammation and epidermal hyperproliferation. A T-lymphocyte-mediated autoimmune reaction induced by bacterial superantigens might be central in its pathogenesis. To model psoriasiform inflammation, we transplanted clinically uninvolved skin from psoriatic patients onto SCID mice. Repetitive intradermal injections with a bacterial superantigen and simultaneous intraperitoneal injections with the patients superantigen-stimulated peripheral mononuclear blood cells resulted in an inflammatory reaction exhibiting some of the hallmarks of psoriasis, e.g. epidermal hyperproliferation, papillomatosis, focal neo-expression of ICAMI, and an exocytotic T-lymphocytic infiltrate characterized by the expression of the cutaneous lymphocyte-associated antigen. These observations document the potential of superantigens to trigger psoriasiform dermatitis and provide a model to study lymphocyte homing.

Animals↗
PubMed1997

Leg ulcers in Klinefelter's syndrome--further evidence for an involvement of plasminogen activator inhibitor-1.

An abnormality in platelet aggregability or fibrinolysis, namely elevated activity of plasminogen activator inhibitor-1 (PAI-1), has been recently documented in patients suffering from Klinefelter's syndrome associated with leg ulceration without underlying venous insufficiency. To determine whether increased PAI-1 activity is a general feature of Klinefelter's syndrome, or more specifically associated with leg ulceration, we investigated PAI-1 influencing parameters and PAI-1 activity in two groups of patients: (i) Klinefelter patients suffering from leg ulceration (n = 7); and (ii) Klinefelter patients without leg ulceration (n = 6). On analysing PAI-1 influencing parameters such as age, body mass index, triglycerides, C-reactive protein, testosterone, smoking behaviour, the presence of diabetes mellitus, and arterial hypertension, respectively, we found no statistically significant differences between the two groups. However, PAI-1 activity in group 1 was highly significantly elevated compared with that in group two patients (P < 0.005). We conclude that (i) PAI-1 activity is not elevated in Klinefelter's syndrome in general; (ii) elevation of PAI-1 activity in patients suffering from Klinefelter's syndrome does not appear to be secondary to PAI-1 influencing parameters; and (iii) elevation of PAI-1 activity may play a crucial role in the pathogenesis of leg ulceration in Klinefelter's syndrome. Therefore, a therapy for leg ulceration in Klinefelter's syndrome that aims to return the elevated PAI-1 activity to normal should be explored.

Arterial Occlusive Diseases↗
PubMed1996

Signaling effects of alpha-thrombin and SFLLRN in rat glioma C6 cells.

Effects of thrombin on brain cells, including change of neurite outgrowth and astrocyte shape, are described, but the molecular mechanisms are unclear. We investigated the effects of human alpha-thrombin and a six amino acid thrombin receptor activating peptide (TRAP-6, SFLLRN) on [Ca2+]i, phosphoinositide hydrolysis, and protein kinase C in rat glioma C6 cells. Stimulation of C6 cells with both alpha-thrombin and TRAP-6 resulted in [Ca2+]i mobilization, [3H]Inositol phosphate response, and enhanced immunoreactivity of the protein kinase C (PKC) isoenzymes alpha, beta, gamma, delta, and epsilon. Results suggest that alpha-thrombin and TRAP-6 activate at least partially the same intracellular signaling pathways in rat glioma C6 cells, which is evidence for involvement of "tethered ligand" receptor in thrombin induced signaling in glioma C6 cells.

Animals↗
PubMed1996

Pharmacological characterization of CCKB receptors in human brain: no evidence for receptor heterogeneity.

In this paper, cholecystokinin (CCK) B-type binding sites were characterized with receptor binding studies in different human brain regions (various parts of cerebral cortex, basal ganglia, hippocampus, thalamus, cerebellar cortex) collected from 22 human postmortem brains. With the exception of the thalamus, where no specific CCK binding sites were found, a pharmacological characterization demonstrated a single class of high affinity CCK sites in all brain areas investigated. Receptor densities ranged from 0.5 fmol/mg protein (hippocampus) to 8.4 fmol/mg protein (nucleus caudatus). These CCK binding sites displayed a typical CCKA binding profile as shown in competition studies by using different CCK-related compounds and non peptide CCK antagonists discriminating between CCKA and CCKB sites. The rank order of agonist or antagonist potency in inhibiting specific sulphated [propionyl-3H]cholecystokinin octapeptide binding was similar and highly correlated for the brain regions investigated as demonstrated by a computer-assisted analysis. Therefore it is concluded that CCKB binding sites in human cerebral cortex, basal ganglia, cerebellar cortex share identical ligand binding characteristics.

Adult↗
PubMed1996

Analysis of carotenoids and carotenol fatty acid esters by matrix-assisted laser desorption ionization (MALDI) and MALDI-post-source-decay mass spectrometry.

Matrix-assisted laser desorption ionization (MALDI) time-of-flight mass spectrometry and MALDI post-source-decay (PSD) fragment ion mass analysis were employed to examine various model carotenoids and some of their fatty acid esters. It was demonstrated that the use of MALDI helps overcome problems resulting from the inherent thermal instability and lack of solubility which render this group of compounds rather difficult for conventional ionization techniques. Detection limits were in the subpicomolar range. Rather abundant metastable fragmentation occurred under conditions of prompt extraction, but was significantly restricted under conditions of delayed extraction (DE). In DE the quasimolecular ion signals (mainly as odd electron radical ions) became the base peak even in spectra of the most delicate fatty acid esters. PSD fragment ion patterns were similar to those recorded under linked B/E scanning in conventional fast atom bombardment-MS and contained information on structural end group substituents such as hydroxyl, epoxide, or carbonyl functions and on the extent of double bond conjugations. The mono- and bis-fatty acid esters fragmented mainly by simple fatty acid cleavage but also furnished some of the end group-specific fragments.

Carotenoids↗
PubMed1996

[Results of treatment of multiple trauma in 130 children].

Trauma remains the leading cause of death in the pediatric age group, despite recent advances in prevention and treatment. We retrospectively analyzed 130 cases of multiple trauma among 725 pediatric patients with injuries treated here during 1988-1989. Road accidents and falls from heights were the most common causes of injury. Mean age was 7 years (range 0.5-15) and the male to female ratio 2.7:1.0. Overall mortality was 9.2%. 57 patients (44%) did not get any prehospital medical care and 5 of them with injury severity scores (ISS) greater than 25 died. In contrast 11/18 (61%) of patients with ISS greater than 25 who were treated by medical teams survived. On arrival at the emergency room, 15% were hypothermic ( < 34 degrees C), and 6 were in hypovolemic shock--5 of whom died. Most common injuries were head trauma (91), limb injuries (69), abdominal trauma (34) and thoracic trauma (34). In 39 injury was severe, with pediatric trauma score (PTS) 6 or less, 12 of whom died. All deaths except 1 were associated with severe head injury and with ISS more than 25. There was no mortality in those with PTS more than 7 or ISS less than 25. Thus, the prehospital care of pediatric patients with head injury is associated with high mortality. Absence of mortality in patients with PTS of more than 7 emphasizes the importance of designated trauma centers for these patients.

Adolescent↗
PubMed1996

Pulsed Erbium:YAG laser ablation in cutaneous surgery.

BACKGROUND AND OBJECTIVE: Among the various pulsed midinfrared-lasers studied in skin surgery the 2.94 microns Erbium:YAG laser has been shown to combine most efficacious ablation with least thermal damage due to its unique absorption characteristics in tissue water. A newly developed high-power Erbium:YAG laboratory laser providing output energies (up to 1.5 J/pulse) and repetition rates (up to 15 Hz) appropriate for clinical use enabled us to investigate its potential indications in dermatological surgery. STUDY DESIGN/MATERIALS AND METHODS: Erbium:YAG laser ablation was performed in vitro on pig skin and in vivo on a total of 30 patients presenting with different skin disorders. RESULTS: In vitro ablation efficiency linearly increased with radiant exposure and was inversely correlated with pulse frequency. Ablation rate at 10 Jcm-2 (used clinically) measured from approximately 10 microns (at 10 Hz) to 40 microns (at 1 Hz). Also for high repetition rates thermal necrosis did not exceed 50 microns, corresponding clinically to capillary bleeding after exposure of the dermis. Superficial lesions, such as epidermal nevi, were easily ablated and re-epithelization was unimpaired owing to the absence of tissue necrosis. In tattoos, exposed pigment particles were precisely removed. However, in deeper lesions the casual onset of bleeding impeded the procedure and scar formation was observed after reepithelization. CONCLUSION: Pulsed 2.94 microns Erbium:YAG laser surgery allows an extremely precise etching of delicate superficial skin lesions and also should have a potential for skin resurfacing.

Animals↗
PubMed1996

Comparison of sensitivity towards photodynamic therapy of cutaneous resident and infiltrating cell types in vitro.

BACKGROUND AND OBJECTIVE: Photodynamic therapy (PDT) combines photosensitizers absorbing light in the visible spectral region and irradiation with light of corresponding wavelengths. We analysed the sensitivity of cell lines established from resident cutaneous cells and from transformed lymphocytes towards PDT. STUDY DESIGN/MATERIALS AND METHODS: PDT was performed employing either 630 or 662 nm light or polychromatic red light (600-700 nm) and photosensitizers Photosan-3, delta-aminolevulinic acid, or methylene blue. Proliferation measured by 3H-TdR uptake was determined in human immortalized keratinocytes (HaCaT) and mouse fibroblasts (NIH/3T3) in comparison to human transformed T-(HuT78) and B-lymphocytes (RA1). Additionally, uptake of the photosensitizers was estimated employing video-intensified fluorescence-microscopy (VIFM). RESULTS: Depending on the photosensitizer tested HaCaT and NIH/3T3 exhibited an ED50 up to 10-fold as high as the lymphocytic lines. Polychromatic red light was at least as effective at inducing photodynamic reactions as 630 or 662 nm light. VIFM revealed a positive correlation between sensitivity of a given cell type towards PDT and uptake of the photosensitizers. The differential uptake observed in vitro was confirmed in vivo: A photosensitizer applied topically on a lesion of a patient with mycosis fungoides was found to accumulate preferentially in the lymphocytic infiltrate. CONCLUSION: Selective topical polychromatic PDT seems to be a feasible goal for the treatment of cutaneous lymphomas.

Aminolevulinic Acid↗
PubMed1996

Post-source decay and delayed extraction in matrix-assisted laser desorption/ionization-reflectron time-of-flight mass spectrometry. Are there trade-offs?

By the incorporation of delayed extraction (DE) into matrix-assisted laser desorption/ionization time-of-flight mass spectrometry a dramatic improvement of performance with respect to sensitivity, mass resolution and mass accuracy of precursor ions up to approximately 10 kDa has been achieved. Since DE reduces collisional in-source activation to a large extent, the rate of subsequent metastable decay is considerably reduced. Results are presented which demonstrate that under DE the loss of total post-source decay (PSD) fragment ion yield can be as large as one order of magnitude but that, in terms of sensitivity, part of this loss is balanced by a better S/N ratio which results from a significantly improved mass resolution of the PSD fragment ions (M/delta M up to 1800 compared with M/delta M = 200-500 under prompt extraction). While this compensatory effect is true for the middle to high mass range of PSD fragment ions, it gradually vanishes towards the low mass end of the PSD mass scale where, in the case of linear peptides some important information (immonium ions) is lost. It appears, however, that in the majority of practical PSD work, DE improves the qualty of the PSD spectra and that high energy collisional post-source activation can compensate for the occasional loss of analytical information.

Amino Acid Sequence↗
PubMed1996

[Photodynamic therapy at the threshold of clinical use in disseminated dermatoses].

Photodynamic therapy (PDT) involving the sequential administration of photosensitizing drugs and light has a successful record in the treatment of superficial tumors. Recent investigations document not only cytotoxicity but also immunomodulatory effects of PDT. Cell type as well as state of activation and differentiation are among the parameters influencing susceptibility to PDT, thus allowing targeting of selected cell (sub-)populations. In addition to lasers, non-coherent light sources are also effective. These features, along with current clinical experience, suggest PDT as an interesting alternative to better established photochemotherapies in the treatment of widespread malignant and benign dermatoses.

Humans↗