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Biomedical subjects

C Böhme

Publications and source records attributed to C Böhme.

At least 19 recordsLinked to original sources
PubMed2003

Precise determination of the 2s(1/2)-2p(1/2) splitting in very heavy lithiumlike ions utilizing dielectronic recombination.

The 2s(1/2)-2p(1/2) energy splittings DeltaE(L) of the lithiumlike ions 19779Au76+, 20882Pb79+, and 23892U89+ have been measured at the Experimental Storage Ring, utilizing low energy dielectronic recombination. The resonance energies in total 41 different 1s(2) 2p(1/2)nl(j(')) (n > or =20) autoionizing Rydberg states populated in the dielectronic capture process have been determined. The 2s(1/2)-->2p(1/2) excitation energies have been obtained by extrapolation of these resonance energies to the associated series limits n--> infinity. The combined analysis of the experimental data for all three ions yields DeltaE(L)=216.134(96) eV for Au76+, 230.650(81) eV for Pb79+, and 280.516(99) eV for U89+.

Journal Article↗
PubMed2003

[Plasma levels of ropivacaine and bupivacaine during postoperative patient controlled thoracic epidural analgesia].

BACKGROUND: The postoperative continuous epidural application of local anesthetics can cause side effects like motor blockade and systemic intoxication. The study was performed to evaluate the plasma levels of two local anesthetics and their analgesic and side effects in continuous postoperative epidural analgesia. METHODS: In a prospective, randomized and double-blind study we have compared side effects of ropivacaine 0.375% (group R) vs. bupivacaine 0.125% in combination with sufentanil 0.5 microg ml(-1) (group B/S) via thoracic epidural catheters for a duration of 96 hours after major abdominal surgery in 30 gynaecological tumor patients. Analgesic effects, side effects and plasma levels of the respective local anesthetic were measured 24, 48, 72 and 96 h after start of epidural infusion. RESULTS: No differences were seen in demographics, perioperative data and analgesic effects. The following cumulative doses of local anesthetics were applied (Group R vs. B/S (median/minimum-maximum ml)): 24 h: 151/121-225 vs. 141/83-171; 48 h: 311/237-424 vs. 299/184-497; 72 h: 454/366-566 vs. 440/256-598; 96 h: 572/399-859 vs. 568/284-711. Plasma levels of local anesthetics remained far below the toxic threshold of 0.6 micro g/ml (Group R vs. B/S (median/minimum-maximum micro g/ml): 24 h: 0.05/0.03-0.24 vs. 0.0/0.0-0.02; 48 h: 0.06/0.02-0.15 vs. 0.006/0.0-0.02; 72 h: 0.05/0.0-0.11 vs. 0.0/0.0-0.02; 96 h: 0.02/0.01-0.32 vs. 0.0/0.0-0.01). The incidence and intensity of motor block (Bromage scale) and other side effects did also not differ between groups. CONCLUSION: The present study shows that thoracic epidural infusion with bupivacaine 0.125% and with a higher concentration of ropivacaine 0.375% during 96 h provides plasma levels of unbound local anesthetic far below the toxic threshold.

Adult↗
PubMed2001

Flow-induced pressure differentially regulates endothelin-1, urotensin II, adrenomedullin, and relaxin in pulmonary vascular endothelium.

We hypothesized that increased pulmonary vascular pressure--one of the characteristics of congestive heart failure--directly regulates pulmonary endothelial vasoconstrictors (endothelin-1, urotensin II) and vasodilators (adrenomedullin, relaxin). To this end, we subjected pulmonary artery endothelial cells in a novel flow-chamber model to different shear stresses (17, 29, and 46 dyn/cm(2)) at low and elevated levels of downstream pressure (10 and 30 mm Hg). Application of elevated pressure over 16 h increased gene expression and peptide secretion of endothelin-1 at all shear levels, whereas secretion of adrenomedullin rose via decreased expression of its clearance receptor. In contrast, preprourotensin II mRNA and urotensin II peptide decreased in response to elevated pressure, and relaxin remained unaffected. This is the first study to identify pressure as key regulator of mediator synthesis by pulmonary vascular endothelium. Pressure-induced mediator regulation may represent an early event in the development of secondary pulmonary hypertension.

Adrenomedullin↗
PubMed2001

Antioxidant status and nitric oxide in the malnutrition syndrome kwashiorkor.

The pathophysiology of kwashiorkor, a severe edematous manifestation of malnutrition, is still poorly understood. The syndrome is, however, known to be associated with alterations in redox metabolism. To further elucidate the role of oxidative stress in kwashiorkor, we carried out a longitudinal study on the major blood antioxidants at the St. Joseph's Hospital, Jirapa, Ghana. All kwashiorkor patients (K) were followed up for 20 d. In comparison with local healthy controls (C), the plasma total antioxidant status was reduced to less than 50% in the patients (C, 0.87 +/- 0.21 mM; K, 0.40 +/- 0.20 mM; p<0.001). Similarly, the major plasma antioxidant albumin (C, 40.9 +/- 2.5 g/L; K, 19.1 +/- 7.4 g/L; p < 0.001) and erythrocyte glutathione (C, 2.39 +/- 0.28 mM; K, 1.01 +/- 0.33; p < 0.001) were decreased, whereas the levels of bilirubin and uric acid were not significantly altered. Nitrite and nitrate were found to be increased by a factor of 2 in kwashiorkor (C, 120 +/- 46 microM; K, 235 +/- 107 microM; p < 0.001). Over the observation period, the trends of albumin and glutathione levels were related to clinical outcome. These concentrations rose in patients who recovered and fell in patients who did not. Our study strongly supports the hypothesis that oxidative and nitrosative stress play a role in the pathophysiology of edematous malnutrition. Prophylactic and therapeutic strategies should aim at the careful correction of the reduced antioxidant status of the patients.

Adolescent↗
PubMed2000

Anti-HER2 therapy: how to use Herceptin in clinical practice.

The recombinant, humanized monoclonal antibody Herceptin is administered as an initial 4 mg/kg i.v. infusion over 90 min, followed by weekly 2 mg/kg i.v. infusions over 30 min. In pivotal clinical trials Herceptin, both as a single agent and in combination with chemotherapy, was found to produce a significant survival benefit in HER2-positive metastatic breast cancer patients. Importantly, Herceptin was well tolerated and was not associated with a poor side-effect profile, producing mainly mild to moderate side-effects. These were generally associated with the initial infusion. The incidence of adverse events was low with Herceptin therapy and severe vomiting and alopecia, typical of many chemotherapy treatment regimens, were not experienced by patients in the trials. Cardiac dysfunction was the most significant Herceptin-related adverse event but could, in most cases, be managed using standard therapy. The favourable adverse event profile seen with Herceptin is reflected in the quality of life (QoL) data. The health-related QoL of patients receiving Herceptin therapy alone or in combination with chemotherapy was found to be maintained. Previous studies have noted a deterioration of health-related QoL in patients treated with chemotherapy only. Thus, as well as providing significant survival benefit, Herceptin therapy improves patient well being.

Journal Article↗
PubMed1998

Monotherapy with piperacillin/tazobactam versus combination therapy with ceftazidime plus amikacin as an empiric therapy for fever in neutropenic cancer patients.

Between July 1993 and September 1996, 107 consecutive febrile episodes in 83 neutropenic cancer patients with a median age of 41 years were randomized to treatment either with piperacillin/tazobactam 4.5 g every 8 h i.v. or ceftazidime 2 g every 8 h plus amikacin 15 mg/kg i.v. per day. In the case of fever > 38 degrees C 48 h after initiation of the antibiotic therapy, vancomycin 500 mg every 6 h i.v. was added. The study population was at serious risk of a poor outcome, since 67% of the patients had leukemia or lymphoma, 19% of the febrile events occurred after autologous bone marrow or blood stem cell transplantation, the median total duration of neutropenia was 16 days, and the median neutrophil count at study inclusion was 0.09 x 10(9)/1. The two patient groups were comparable in terms of risk factors. Bacteremia was found in 37%, other microscopically documented infections in 16%, and clinically documented infections in 26% of the febrile episodes. Most (96) febrile episodes were evaluable for response. No significant difference was found between piperacillin/ tazobactam and ceftazidime plus amikacin in terms of success rate (81% versus 83%), empirical addition of vancomycin (42% versus 38%), median time to fever defervescence (3.3 versus 2.9 days) or median duration of antibiotic therapy (7.2 versus 7.4 days). No patient died from the infection. Both antibiotic regimens were well tolerated, the study treatment being stopped only in 1 patient because of toxicity (cutaneous allergy to piperacillin/tazobactam). On the basis of the 107 febrile events encountered, we conclude that piperacillin/tazobactam is a safe and effective monotherapy. To define the definitive value of piperacillin/ tazobactam as a monotherapy for febrile neutropenic patients a large randomized trial is warranted.

Adolescent↗
PubMed1996

Morphology of locust neurosecretory cells projecting into the Nervus corporis allati II of the suboesophageal ganglion.

The morphology of neurosecretory cells that project from the suboesophageal ganglion into the retrocerebral complex via the Nervus corporis allati II (NCA II) was studied in the migratory locust, Locusta migratoria, using backfilling techniques and intracellular staining. There are two populations of cells located ventrally in the ganglion: an anterior group of four larger cells, and a posterior group of up to 22 smaller cells. Apart from cell body size and position, members of both cell groups have almost all features in common. They show long-lasting soma spikes with large amplitudes typical for arthropod neurosecretory cells. Their dendritic arborisations are found in the same regions of the neuropile. Both types project into the corpora cardiaca and an additional putative neurohaemal region associated with posterior pharyngeal dilator muscles. The axons of the cells bypass the corpora allata, but frequently form putative release sites on the surface of nerve branches in the vicinity of these glands. Finally, using double-labelling techniques, both anterior and posterior cells are shown to be identical with immunoreactive suboesophageal ganglion cells detected in previous studies using antisera directed against either bovine pancreatic polypeptide (BPP) or locustamyotropin II (Lom-MT-II).

Animals↗
PubMed1994

Evaluation of membranes for use in on-line cell separation during mammalian cell perfusion processes.

In this study two microporous hollow fibre membranes were evaluated for their use as cell retention device in continuous perfusion systems. A chemically modified permanent hydrophillic PTFE membrane and a hydrophilized PP membrane were tested. To investigate the filtration characteristic under process conditions each membrane was tested during a long term perfusion cultivation of a hybridoma cell line. In both cultivations the conditions influencing membrane filtration (e.g. transmembrane flux) were kept constant. Filtration behaviour was investigated by monitoring transmembrane pressure and protein permeability. Transmembrane pressure was measured on-line with an autoclavable piezo-resistive pressure sensor. Protein permeability was determined by quantitative evaluation of unreduced, Coomassie stained SDS-PAGE. The membrane fouling process influences the filtration characteristic of both membranes in a different way. After fermentation the PP membrane was blocked by a thick gel layer located in the big outer pores of the asymmetric membrane structure. The hydraulic resistance was higher but the protein permeability was slightly better than of the PTFE membrane. For this reason the PP membrane should be preferred. On the other hand, transmembrane pressure decreases slower when the PTFE membrane is used, which favours this membrane for long term cultivations, especially when low molecular weight proteins (< 30 KD) are produced.

Animals↗
PubMed1975

[Metabolism of 3-amino-1,2,4-triazole in rats].

3-Amino-1,2,4-triazole[5-(14)C] was administered orally to rats as a single dose of 50 mg/kg body weight. Excretion in urine and feces was followed during a period of 3 days. Within the first 24 hrs the main part of the radioactivity was found in the urine as unchanged amitrole. 3-Amino-5-mercapto-1,2,4-triazole and 3-amino-1,2,4-triazolyl-(5)-mercapturic acid were isolated from urine and identified by comparison with synthetic compounds. The total amount of these metabolites in the urine was about 6% of the dose. The metabolic pathways of amitrole and the possible relations between biotransformation and toxicity are discussed.

Acetylcysteine↗