Biomedical subjects

Bernd Maier

Publications and source records attributed to Bernd Maier.

5 recordsLinked to original sources

PubMed2006

Delayed elevation of soluble tumor necrosis factor receptors p75 and p55 in cerebrospinal fluid and plasma after traumatic brain injury.

Recent studies have reported a significant inflammatory reaction in the brain and the systemic circulation after traumatic brain injury (TBI). Although there is growing knowledge and understanding of the mechanisms and mediators involved in the proinflammatory reaction, little is known about the anti-inflammatory mediators in the brain. As tumor necrosis factor alpha (TNF-alpha) plays a detrimental role in the initiation and promotion of the proinflammatory reactions after TBI, the endogenous scavenger system, represented by the soluble TNF receptors (sTNFRs) p55 and p75, seems to have an important anti-inflammatory capacity by binding to circulating TNF-alpha. To evaluate this potentially anti-inflammatory response to trauma, we analyzed sTNFR p55 and p75 in paired plasma/cerebrospinal fluid (CSF) samples of 29 patients who encountered TBI. Values were compared with reference values obtained from healthy volunteers (n = 91). Patients with TBI showed significantly (P < 0.001) elevated sTNFR p55 and p75 values starting from day 2 and lasting until day 10 if compared with reference values. In contrast to the early increased plasma values p55 and p75 showed slowly increasing CSF values starting on day 4 and 3, respectively. Significantly (P < 0.001) increased CSF values of p 55 were determined on days 4 to 6 and day 9. p75 showed significantly (P < 0.001) elevated values if compared with control values on days 7 and 9. The sTNFR p55 and p75 show a distinct and long-lasting elevation in plasma of patients after TBI. In contrast, CSF values display a delayed and less intense elevation of both receptors in patients with TBI. These findings are suggestive of an imbalance of the proinflammatory and anti-inflammatory reactions of the central nervous system after trauma, with an emphasis on the proinflammatory mechanisms and a slow increase of potentially anti-inflammatory mediators such as the soluble TNFRs after TBI.

Adolescent↗

PubMed2005

The oxygen mass transfer, carbon dioxide inhibition, heat removal, and the energy and cost efficiencies of high pressure fermentation.

This study focuses on the enhancement of oxygen transfer in aerobic fermentation processes through the use of the reactor headspace pressure as a process variable. Our investigation was performed using an example 5 m3 fermentor, and by applying the mass transfer (sorption) characteristics obtained from measurements with Pseudomonas putida CA-3 in a mineral medium. By applying reactor pressures up to 11 bar (10 bar overpressure) the oxygen transfer capacities of stirred tank reactors can theoretically be increased to values above 1 kmol m(-3) h(-1), although the problem of heat removal limits that value to levels of 0.7 kmol m(-3) h(-1). However, this is still sufficient for the oxygenation of most aerobic fermentation processes, even at very high cell densities. Possible inhibition by the carbon dioxide partial pressure at elevated total pressures is discussed. It is shown that increasing reactor pressure enhances the energy efficiency, defined as the ratio of the oxygen transfer capacity to the total power consumption of the reactor system. The cost efficiency of the oxygen mass transfer, defined as the ratio of the oxygen transfer capacity to the overall cost of the system (overall purchase cost divided by a project lifetime of ten years, plus total energy cost) also increases with reactor pressure up to 5.6 bar.

Bioreactors↗

PubMed2005

Fracture and retrosternal dislocation of the medial clavicle in a 12-year-old child--case report, options for diagnosis, and treatment in children.

We report a retrosternally displaced epiphysiolysis in a 12-year-old child and discuss options for the most appropriate diagnostic and therapeutic approach. If a standard anteroposterior view of the shoulder girdle shows abnormalities or if appropriate clinical suspicion is present, we strongly favor an magnetic resonance imaging study for further workup instead of a computed tomographic scan, which is currently the diagnostic method of choice in clinical algorithms. Radiation exposure is thereby limited and maximum information about possible mediastinal soft tissue complications is obtained using a single diagnostic tool. If open reduction is indicated, retention of the joint or approximation of physeal fracture or treatment of ligamentous injury should be performed without metal devices. These suggestions for future management of these patients should further reduce the use of x-rays in children. In addition, applying a suture instead of using metal for stabilization can avoid the extensively described complications in literature that can potentially result from metal devices. In addition, sutures circumvent the need for a second operation for metal removal.

Accidental Falls↗

PubMed2005

Physiological levels of pro- and anti-inflammatory mediators in cerebrospinal fluid and plasma: a normative study.

Numerous recent studies have reported a significant inflammatory reaction in the brain and the systemic circulation following traumatic brain injury (TBI), infection, or neoplasm of the brain with a sequential release of pro- and anti-inflammatory mediators. Although there is growing knowledge and understanding of the mechanisms leading to the often poor outcome of these patients, only a limited database exists on the physiological expression of pro- and anti-inflammatory cytokines and molecules in plasma and particularly in cerebrospinal fluid (CSF). Therefore, we analyzed paired plasma/CSF samples of healthy human volunteers for the physiological concentrations of Interleukin (IL)-6, IL-8, IL-10, soluble TNF-receptors (sTNF-R) p55 and p75, soluble ICAM (sICAM), and soluble E-selectin (sE-selectin). A physiological release of IL-6, IL-8, IL-10, and sTNF-R p55 and p75 was detected in plasma and CSF. In contrast, sICAM and sE-selectin were only detectable in plasma. Pro- and anti-inflammatory mediators exhibited different concentration patterns in plasma and CSF, suggesting a pro-inflammatory predisposition in the central nervous system.

Adult↗

PubMedDate not supplied

A novel parallel shaken bioreactor system for continuous operation.

A novel continuous bioreactor system was developed as a shaken culture vessel for the investigation of the growth kinetics and product formation of microorganisms in milliscale. The novel bioreactor system mainly consists of a specially designed 250-mL shake flask with two inlets, one for gas supply and one for medium supply, and one combined outlet on the side of flask for exhaust gas and culture liquid. As a result of the circulating motion of the fermentation broth in the shake flask, the maximum liquid height reaches the edge of the outlet and the fermentation broth is accelerated into the outlet by centrifugal force. Additionally, the excess fermentation broth leaving the culture vessel is continuously driven by the exhaust gas. Because of the small scale and the simple handling it is possible to operate many of these shaken bioreactor vessels simultaneously. By using parallel vessels operated at different dilution rates on the same shaker, the data for a complete biomass over dilution rate (X-D) diagram of a biological culture can be evaluated in an efficient manner, thus saving money, materials, and time. Continuous fermentations of the yeast Saccharomyces cerevisiae H1022 (ATCC 32167) in the shaken bioreactor system and in a conventional stirred tank fermentor showed very similar results.

Bioreactors↗