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Biomedical subjects

B Wagner

Publications and source records attributed to B Wagner.

At least 91 records · Page 5Linked to original sources
PubMed1997

[A delayed hemolytic transfusion reaction due to irregular antibodies with an anti-Kidd(a) specificity].

HISTORY AND CLINICAL FINDINGS: A 56-year-old woman was admitted for replacement of a previously implanted right hip prosthesis which had become loose (no infection). She limped painfully on a shortened leg whose mobility was markedly impaired. At the site of the previous operation the pelvis was lower by about 2 cm; the scar looked well healed. INVESTIGATIONS: Routine laboratory tests were normal except for moderately raised erythrocyte sedimentation rate (18/ 27 mm). There was complete loosening of the prosthesis on X-ray. TREATMENT AND COURSE: Intraoperative bleeding from a branch of the inferior gluteal artery required blood transfusion and further erythrocyte infusions became necessary. Jaundice developed on the 4th postoperative day and 7 days later the direct Coombs test was positive with demonstrable agglutination. Free irregular erythrocytic anti-Kidd(a) (anti-jk[a]) antibodies were found in the serum. To counteract the delayed haemolytic transfusion reaction, exclusively jk(a)-negative erythrocytes were infused. The jaundice gradually disappeared and the bilirubin values became normal. CONCLUSION: Jaundice and signs of haemolysis after erythrocyte transfusion may be due to delayed transfusion reaction and should be investigated with the direct Coombs test.

Antibodies↗
PubMed1997

Experimental gluing of the bronchial stump after pneumonectomy in rats.

OBJECTIVE: The objective of this experimental study was to evaluate the usefulness of gelatin-resorcinol-dialdehyde adhesive in sutureless closure of bronchial stumps. METHODS: In 40 male Wistar rats bronchial stumps after left-sided pneumonectomy were closed by gluing with gelatin-resorcinol-dialdehyde adhesive. For macroscopic and microscopic examination four animals were sacrificed on postoperative days 2, 7 and 14 each, 14 animals on postoperative days 28 and 120 each. RESULTS: On macroscopic examination the gelatin-resorcinol-dialdehyde adhesive proved in all cases effective in tight bronchial stump closure. The adhesive did not cause local infection or necrosis of the bronchial stump nor other intrathoracic inflammatory complications. All animals survived and made an uncomplicated postoperative recovery. Microscopic examination revealed that the gelatin-resorcinol-dialdehyde adhesive initially evoked an acute inflammatory response with polymorphonuclear neutrophils predominating. After an intermediate stage characterized by a granulomatous reaction and resorption of the adhesive by multinucleated giant cells, 120 days postoperatively the bronchial stumps at the sites of previous gluing showed a regular fibrous scar tissue without inflammatory cells. CONCLUSION: The gelatin-resorcinol-dialdehyde adhesive showed effective in closing bronchial stumps after pneumonectomy in rats. The clinical extrapolation of this effect to thoracic surgical patients is uncertain at this time.

Animals↗
PubMed1997

Experimental gluing of lung parenchyma in rats.

Gelatin-resorcinol-dialdehyde adhesive has been developed from a gelatin-resorcinol-formaldehyde adhesive by replacing the formaldehyde with two less histotoxic dialdehydes, ethandial and pentandial. The aim of the present study was to evaluate the usefulness of this modified composition in gluing defects in lung parenchyma. In 40 male Wistar rats a standardized lung incision 1.0 cm in length and 0.8 cm in depth were closed by application of gelatin-resorcinol-dialdehyde adhesive. For macroscopic and microscopic examination 4 animals were sacrificed on each of postoperative days 2, 7, and 14 and 14 animals on each of postoperative days 28 and 120. Macroscopic examination revealed a tight closure of the parenchymal defects in all postoperative stages. Initially by an adhesive layer and later on by granulation tissue and scar tissue respectively. On microscopic examination an inflammatory tissue response with polymorphonuclear neutrophils and macrophages predominating was found 2 days postoperatively. After 7 days multinucleated giant cells appeared. On postoperative day 14 the tissue response presented a distinct granulomatous character with multinucleated giant cells persisting. After 28 days remnants of adhesive surrounded by granulation tissue were detectable. On postoperative day 120 the adhesive had been completely resorbed and the parenchymal defect was replaced by fibrous scar tissue. The gelatin-resorcinol-adhesive proved effective in tight closure of lung parenchyma in rats. The adhesive is resorbed completely and does not interfere with parenchymal healing.

Absorption↗
PubMed1997

Measurement of cerebral blood flow in dogs with near infrared spectroscopy in the reflectance mode is invalid.

Near infrared spectroscopy (NIRS) is used to measure CBF (CBFNIRS) in humans, based on Fick's principle, using oxygen as an intravascular tracer. We compared CBFNIRS with CBF measured by microspheres (CBF mu) and the venous outflow technique (CBFv) in 15 dogs, altering CBF with ventilation-induced changes in PaCO2. Five hundred forty-nine CBFNIRS measurements were attempted using an integration time of 2.5 s on the saturation signal from the tongue. One hundred ninety-eight (36.1%) of the measurements fulfilled predefined criteria. The coefficient of variation (CV) for six measurements under stable conditions was 29.1%. The CBFNIRS measurements correlated best with microsphere-measured blood flows in the cortical gray matter (median 0.43, range 0.16-0.93); the contributions of the skull and dura were variable. The CBFv varied by a médian of 12% (range 0-67%) during the CBFNIRS measurements. The percentage of acceptable CBFNIRS measurements, the CV, and the correlation coefficients of the CBFNIRS were improved by using saturation signal directly from the artery and varying the integration time with an estimate of the minimum transit time. The current method of measuring CBFNIRS in the reflectance mode is in-accurate when compared with other accepted techniques.

Animals↗
PubMed1997

Identification of N2-fixing plant- and fungus-associated Azoarcus species by PCR-based genomic fingerprints.

Most species of the diazotrophic Proteobacteria Azoarcus spp. occur in association with grass roots, while A. tolulyticus and A. evansii are soil bacteria not associated with a plant host. To facilitate species identification and strain comparison, we developed a protocol for PCR-generated genomic fingerprints, using an automated sequencer for fragment analysis. Commonly used primers targeted to REP (repetitive extragenic palindromic) and ERIC (enterobacterial repetitive intergenic consensus) sequence elements failed to amplify fragments from the two species tested. In contrast, the BOX-PCR assay (targeted to repetitive intergenic sequence elements of Streptococcus) yielded species-specific genomic fingerprints with some strain-specific differences. PCR profiles of an additional PCR assay using primers targeted to tRNA genes (tDNA-PCR, for tRNA(IIe)) were more discriminative, allowing differentiation at species-specific (for two species) or infraspecies-specific level. Our protocol of several consecutive PCR assays consisted of 16S ribosomal DNA (rDNA)-targeted, genus-specific PCR followed by BOX- and tDNA-PCR; it enabled us to assign new diazotrophic isolates originating from fungal resting stages (sclerotia) to known species of Azoarcus. The assignment was confirmed by phylogenetic analysis of 16S rDNA sequences. Additionally, the phylogenetic distances and the lack of monophyly suggested emendment of the genus Azoarcus: the unnamed species Azoarcus groups C and D and a new group (E) of Azoarcus, which was detected in association with fungi, are likely to have the taxonomic rank of three different genera. According to its small subunit rRNA, the sclerotium-forming basidiomycete was related to the Ustilagomycetes, facultatively biotrophic parasites of plants. Since they occurred in a field which was under cultivation with rice and wheat, these fungi might serve as a niche for survival for Azoarcus in the soil and as a source for reinfection of plants.

Bacteria↗
PubMed1997

Purification and characterization of 2,4,6-trichlorophenol-4-monooxygenase, a dehalogenating enzyme from Azotobacter sp. strain GP1.

The enzyme which catalyzes the dehalogenation of 2,4,6-trichlorophenol (TCP) was purified to apparent homogeneity from an extract of TCP-induced cells of Azotobacter sp. strain GP1. The initial step of TCP degradation in this bacterium is inducible by TCP; no activity was found in succinate-grown cells or in phenol-induced cells. NADH, flavin adenine dinucleotide, and O2 are required as cofactors. As reaction products, 2,6-dichlorohydroquinone and Cl- ions were identified. Studies of the stoichiometry revealed the consumption of 2 mol of NADH plus 1 mol of O2 per mol of TCP and the formation of 1 mol of Cl- ions. No evidence for membrane association or for a multicomponent system was obtained. Molecular masses of 240 kDa for the native enzyme and 60 kDa for the subunit were determined, indicating a homotetrameric structure. Cross-linking studies with dimethylsuberimidate were consistent with this finding. TCP was the best substrate for 2,4,6-trichlorophenol-4-monooxygenase (TCP-4-monooxygenase). The majority of other chlorophenols converted by the enzyme bear a chloro substituent in the 4-position. 2,6-Dichlorophenol, also accepted as a substrate, was hydroxylated in the 4-position to 2,6-dichlorohydroquinone in a nondehalogenating reaction. NADH and O2 were consumed by the pure enzyme also in the absence of TCP with simultaneous production of H2O2. The NH2-terminal amino acid sequence of TCP-4-monooxygenase from Azotobacter sp. strain GP1 revealed complete identity with the nucleotide-derived sequence from the analogous enzyme from Pseudomonas pickettii and a high degree of homology with two nondehalogenating monooxygenases. The similarity in enzyme properties and the possible evolutionary relatedness of dehalogenating and nondehalogenating monooxygenases are discussed.

Amino Acid Sequence↗
PubMed1997

Effects of meloxicam and indomethacin on cyclooxygenase pathways in healthy volunteers.

BACKGROUND: Meloxicam is a new NSAID with selectivity for the inducible cyclooxygenase (COX-2) in vitro. We compared the effects of therapeutically equivalent doses of meloxicam and indomethacin, a preferential inhibitor of the constitutive cyclooxygenase (COX-1), on platelet aggregation and platelet thromboxane formation, which are exclusively COX-1 dependent, physiological renal, and total body prostaglandin E2 (PGE2) production. METHODS: In a randomized cross-over design, 14 healthy female volunteers received meloxicam 7.5 mg per day for 6 days or indomethacin 25 mg three times per day for 3 days; the wash-out period was 5 days, and drug intake was adapted to the menstrual cycle. On the day before treatment and on the last day of each treatment period the following parameters were evaluated: maximum platelet aggregation and thromboxane B2 (TXB2) formation in response to 1.0 mmol/L arachidonic acid; 24-hour urinary excretion of PGE2 and 7 alpha-hydroxy-5, 11-diketo-tetranor-prosta-1, 16-dionic acid (PGE-M), the index metabolites of renal and total body PGE2 synthesis, respectively, were assessed by gas chromatography/tandem mass spectrometry. RESULTS: Maximum platelet aggregation and TXB2 formation were almost completely inhibited by indomethacin (-87% and -99%, respectively; p < 0.001, each) as compared to control (100%), but remained unaffected by meloxicam (-1% and +4%, respectively). Meloxicam showed no significant effects on urinary PGE2 excretion (-13%) and only slight effects on PGE-M excretion (-22%; p < 0.05), whereas indomethacin reduced urinary PGE2 excretion (-43%; p < 0.05) as well as PGE-M excretion (-36%; p < 0.001). CONCLUSIONS: Our data show, that meloxicam 7.5 mg per day is COX-1 sparing in humans in vivo.

Adult↗
PubMed1997

[Future population growth in the Augsburg area--model calculations using the DEPOP model].

Regional population forecasts are on average even more uncertain than nationwide projections, due to the greater importance of migration and the unstable smaller absolute numbers. Other than national projections, local or regional calculations do normally have an explicit goal. In this paper, a projection of the population and age structure in the region of Augsburg is used to demonstrate some specific aspects of local population projections used for public health purposes. If institutions of childhood ages are to be projected the results are primarily determined by the assumptions on migration. If questions of old age are to be answered, the main factor of influence is the development in mortality. Depending on the specific alm of a local population projection, the principal insecurity about the future should be integrated by calculating confidence bands for those demographic parameters, that are most important for the specific question.

Adolescent↗
PubMed1997

[Effect of gamma-hydroxybutyric acid and pentoxifylline on kidney function parameters in coronary surgery interventions].

After cardiac surgery, transient renal dysfunction often occurs. The main reasons for impairment of renal function are intraoperative hypotension, ischemia/reperfusion injury and inflammatory response to cardiopulmonary bypass (CPB). Pentoxifylline is known to have anti-inflammatory properties. Gamma-hydroxybutyrate (GHB), an endogenous regulator of energy metabolism, showed beneficial effects on experimental intestinal ischemia/reperfusion injury and liver graft function. Both drugs may be of practical interest in diminishing renal damage during and after cardiac surgery. After approval by the ethics committee and informed consent, 45 patients for elective coronary artery bypass grafting with no clinical and laboratory impairment of renal function were randomized into 3 groups (15 patients each): group 1 received saline as control, group 2 received pentoxifylline intraoperatively (1 mg/kg/h after a priming dose of 1 mg/kg) and group 3 received GHB intraoperatively (25 mg/kg/h after a priming dose of 25 mg/kg) in a double-blinded fashion. During 3 periods (before CPB, from the beginning of CPB until the end of surgery, 24 hours postoperatively), glomerular (creatinine clearance, CCr) and tubular markers of renal function (beta-NAG, alpha 1-microglobulin) were detected in addition to clinical routine standards (creatinine, urea, fractional excretion of sodium). Changes in glomerular and in tubular function were comparable in all groups without characteristic effects of either GHB or pentoxifylline. With CPB, CCr decreased significantly until the end of operation, but showed a rise to preoperative levels on the first day after operation. Tubular function markers (beta-NAG, alpha 1-microglobulin, related to simultaneous excretion of creatinine) showed a remarkable rise after the beginning of CPB up to the postoperative period. The results of the present pilot study suggest the detection of tubular proteins and enzymes a useful addition to present routine clinical standards for recognizing early intraoperative changes in renal function. In the patients studied, there were no clinical signs of renal dysfunction. Neither GHB nor pentoxifylline--in the doses applied--was able to show a therapeutic benefit despite the theoretical advantages.

Aged↗