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Biomedical subjects

A Bach

Publications and source records attributed to A Bach.

At least 55 records · Page 3Linked to original sources
PubMed2000

[Tissue engineering: possibilities and perspectives].

Successful tissue engineering requires intensive co-oporation between clinicians, biologists (cell culture, gene therapy), chemical engineers (biomaterials) and industrial partners. In case of wound healing tissue engineered constructs have already been applied successfully in burns and chronic wounds. In order to improve carrier and matrix function biomaterials still have to be optimized. The potential of such constructs might even be enhanced by gene therapeutical methods. The complex mammalian organism has to be considered as the gold standard and the model for perfect tissue engineering. The problem of vascularization of complex organs yet has to be solved. In general it seems to be more promising to substitute deficient components in vivo and to rely on modulating influences within the host organism rather than to create complex organs ex vivo.

Animals↗
PubMed2000

[Cost control in anesthesiology--regulating net costs exemplified by anesthetics].

German hospitals are beginning to feel more and more pressure due to rising costs in health care. These are due to continuous increase in health care expenditure and decrease in state insurance contributions. A change in the state insurance system (GKV) is well and truly overdue; the source of income needs to be increased by either raising the compulsory insurance wage base or making other forms of income liable for insurance contributions. Unfortunately, the government is still reluctant to take action. The ruling coalition feels that it is better to limit the increase in expenditure on hospital care by introducing a case-related payment system. Unfortunately, they do not recognize that the main reason for the increase in health care expenditure is the growing medical potential and the higher morbidity of an, on average, older population. These cuts in financial means demand an efficient allocation of the available funds. As far as hospital in-patient care is concerned, this means that hospitals need to reconsider their expenditure and that economic success is dependent on their potential to recognize ways of reducing overall costs. This article illustrates that before the "Diagnosis Related Groups" (DRG) become effective in 2003, one needs to establish the cost price of individual hospital cases. The economic principles of cost-benefit ratios and methods to prevent cost inflation are presented. The methods of making a cost-effectiveness analysis of anaesthetic costs are explained in detail. The aim of this paper is to give the clinician a better understanding of cost management and to motivate staff to initiate cost-control studies.

Anesthesiology↗
PubMed1999

DSD-1-proteoglycan is the mouse homolog of phosphacan and displays opposing effects on neurite outgrowth dependent on neuronal lineage.

DSD-1-PG is a chondroitin sulfate proteoglycan (CSPG) expressed by glial cells that can promote neurite outgrowth from rat embryonic mesencephalic (E14) and hippocampal (E18) neurons, an activity that is associated with the CS glycosaminoglycans (GAGs). Further characterization of DSD-1-PG has included sequencing of peptides from the core protein and the cloning of the corresponding cDNA using polyclonal antisera against DSD-1-PG to screen phage expression libraries. On the basis of these studies we have identified DSD-1-PG as the mouse homolog of phosphacan, a neural rat CSPG. Monoclonal antibodies 3H1 and 3F8 against carbohydrate residues on rat phosphacan recognize these epitopes on DSD-1-PG. The epitopes of the antibodies, L2/HNK-1 and L5/Lewis-X, which have been implicated in functional interactions, are also found on DSD-1-PG. Although DSD-1-PG has previously been shown to promote neurite outgrowth, its upregulation after stab wounding of the CNS and its localization in regions that are considered boundaries to axonal extension suggested that it may also have inhibitory functions. Neonatal dorsal root ganglion (DRG) explants grown on a rich supportive substrate (laminin) with and without DSD-1-PG were strikingly inhibited by the proteoglycan. The inhibitory effects of DSD-1-PG on the DRG explants were not relieved by removal of the CS GAGs, indicating that this activity is associated with the core glycoprotein. The neurite outgrowth from embryonic hippocampal neurons on laminin was not affected by the addition of DSD-1-PG. This indicates that DSD-1-PG/mouse phosphacan can have opposing effects on the process of neurite outgrowth dependent on neuronal lineage.

Amino Acid Sequence↗
PubMed1999

Role of heteromer formation in GABAB receptor function.

Recently, GBR1, a seven-transmembrane domain protein with high affinity for gamma-aminobutyric acid (GABA)B receptor antagonists, was identified. Here, a GBR1-related protein, GBR2, was shown to be coexpressed with GBR1 in many brain regions and to interact with it through a short domain in the carboxyl-terminal cytoplasmic tail. Heterologously expressed GBR2 mediated inhibition of adenylyl cyclase; however, inwardly rectifying potassium channels were activated by GABAB receptor agonists only upon coexpression with GBR1 and GBR2. Thus, the interaction of these receptors appears to be crucial for important physiological effects of GABA and provides a mechanism in receptor signaling pathways that involve a heterotrimeric GTP-binding protein.

Adenylyl Cyclase Inhibitors↗
PubMed1999

Screen for genes regulated during early kidney morphogenesis.

Kidney development starts with the reciprocal induction of mesenchymal and ureteric bud cells which leads to condensation, epithelialization, and nephron formation in the mesenchyme. To identify changes in gene expression during these processes, we compared differential display polymerase chain reaction (PCR) profiles of uninduced and induced mesenchymal cells. In vitro kidney development in the form of the transfilter organ culture system was used to generate homogeneous cell populations for this type of comparison. Here we describe the isolation of known and novel genetags from this screening. Among the known genes the ufo receptor tyrosine kinase, sFRP2, and the groucho related gene (grg) were verified as being upregulated upon induction. With four of eight novel genes tested, Northern blot analysis proved to be sensitive enough to confirm differential expression. To improve sensitivity and gain additional spatial information, in situ hybridization was performed. Expression analysis of two differential display PCR products, designated C0-5 and M2-4, demonstrated the cell-specific and dynamic expression of these novel genetags in the developing kidney and other tissues. C0-5 transcripts were expressed in the ureteric bud, S-shaped bodies, and in the collecting system. Signals for M2-4, a gene not detectable by Northern blot analysis, were only found in condensing mesenchymal cells and early differentiation stages, but not in the collecting ducts. The large fraction of novel genetags from the present screening that have not yet been analyzed provides a rich resource to clone genetic networks regulating early nephrogenesis.

Animals↗
PubMed1999

Prevention of infections caused by central venous catheters--established and novel measures.

Intravascular catheters play an important role in infections in intensive care and hemodialysis patients. This becomes evident only if full microbiological diagnoses are made. Difficulties in the diagnosis and treatment of microbially colonized catheters make the prevention of infection particularly important. The most important preventive measures are a strict evaluation of the indications for the use of the catheter and strict hygienic precautions during insertion and maintenance of the central venous catheter. Other measures, some of which are controversial, may be considered, such as the specific decontamination of Staphylococcus carriers using mupirocin. A new approach in the prevention of catheter-related infections is the use of catheter materials impregnated with antibiotics, antiseptics or metals. Slow-delivery systems release the antimicrobially active substance from the catheter material and thus reduce the proliferation of adherent bacteria. Some of these slow-delivery systems have been used in clinical trials, with varied results. Current research is directed towards the prevention of the first stage in the pathogenesis of catheter-associated infections, namely the adherence of bacteria to the catheter polymer, e.g. by impregnation of the polymer with silver. Laboratory studies, animal experiments and initial clinical trials suggest that it will soon be possible to reduce the frequency of catheter-associated infections to below the levels attainable with current general and specific preventive measures, through the use of coated catheters.

Animals↗
PubMed1999

Integration of generic indicators for quality management in hospital information systems.

Hospital information systems may contribute in different ways to quality management activities such as monitoring of quality indicators. Most existing quality management activities in hospitals are adjusted to a special medical field or particular disease. These activities often run simultaneously with other procedures and the documentation of patient care. To determine an interdisciplinary integrated quality management procedure, a pilot study was carried out at the Neurosurgery Department and Neonatology Division of the Medical Center of the University of Heidelberg. Predefined generic indicators that may be integrated in an existing information system and used in hospital routine were the basis of this project. The aim of the study was to support the quality management with periodic reports of these indicators. The pilot study showed that there were barriers along the path to an integrated generic quality management. To meet the requirements of routine monitoring, using predefined generic indicators of hospital care, much integration effort, directed at organizational aspects of information processing and information systems architecture, is still needed.

Germany↗
PubMed1999

Cost-effectiveness analysis in anaesthesia.

In order to preserve the quality of anaesthetic care under cost containment programmes, the concept of value-based anaesthesia was introduced. To achieve this goal, namely, the provision of the best possible care attainable at a reasonable cost, studies are necessary that compare anaesthetic techniques in terms of both quality and costs, e.g. by means of cost-effectiveness analyses.

Journal Article↗
PubMed1999

Efficacy of silver-coating central venous catheters in reducing bacterial colonization.

OBJECTIVE: To compare silver-coated and uncoated central venous catheters regarding bacterial colonization. To assess the relative contribution of catheter hub and skin colonization to catheter tip colonization. DESIGN: Prospective, randomized clinical trial. SETTING: Intensive care unit in a university hospital. PATIENTS: Patients after cardiac surgery who required a central venous double-lumen catheter (DLC). INTERVENTIONS: Sixty-seven adult patients were prospectively randomized to receive either a silver-coated (S group, n = 34) or an uncoated control (C group, n = 33) DLC. Blood cultures were drawn at catheter removal, and removed catheters were analyzed with quantitative cultures. Typing of microorganisms included DNA fingerprinting. MEASUREMENTS AND MAIN RESULTS: Catheters were removed if no longer necessary and aseptically divided into three segments: segment A, the catheter tip; segment B, an intermediate section; and segment C, the subcutaneous portion. Bacterial catheter colonization was quantitatively measured using sonication to detach adherent bacteria from the catheter segments in the broth and subsequent culture of an aliquot. Selected isolates of coagulase-negative staphylococci and other bacteria from catheter segments were examined by means of pulsed-field gel electrophoresis (PFGE) after macrorestriction digestion of bacterial DNA to study colonization pathogenesis. Quantitatively lower bacterial colonization could be demonstrated on the silver-coated catheters (200 +/- 550 colony forming units [CFUs]/cm catheter segment; mean +/- SD). The difference in the control catheters (1120 +/- 5350 CFUs/cm catheter segment; mean +/- SD) was not, however, significant (p = .25). The frequency of colonization of at least one catheter segment was 52.9% for the silver-coated catheters and 57.6% for the control catheters (p= .44), without any significant differences in the colonization of corresponding catheter segments. The rate of significant catheter colonization (i.e., > or = 10(3) CFUs/cm catheter by quantitative catheter culture or > or = 10(3) CFUs/mL by luminal flush) was nine in the silver group and seven in the control group, a difference that failed to reach significance (p = .41). Two patients in both groups developed catheter-related bacteremia. Pattern analysis after PFGE demonstrated that about 70% of the isolates found on the catheter tip were identical with those on the skin at the insertion site, whereas about 75% were identical with those recovered from the hub. In 29% of colonized catheters, identical bacteria were found on the hub and the skin at the insertion site. CONCLUSIONS: Silver-coating of DLCs did not significantly reduce bacterial catheter colonization compared with the control catheters. PFGE analysis of coagulase-negative staphylococci and other bacteria demonstrated various pathogenic routes of catheter-related colonization, whereby the microorganisms of the skin flora around the insertion site must be regarded as the main source of catheter-related infections.

Adult↗
PubMed1999

Effects of different levels of methionine and ruminally undegradable protein on the amino acid profile of effluent from continuous culture fermenters.

Eight dual-flow continuous culture fermenters were used to study the effects of feeding different levels of methionine and ruminally undegradable protein (RUP) on the amino acid (AA) profile of protein residue after microbial fermentation. Four isocaloric (1.76 Mcal/kg of NE(l)) and isonitrogenous (17.7% CP) diets were formulated based on NRC recommendations for a 630-kg cow producing 42 kg/d of milk. Two dietary treatments, diets HmLr (high methionine, low RUP) and HmHr (high methionine, high RUP), were formulated to meet, but not exceed, more than 140% of each estimated individual AA requirement for milk production. Diets LmLr (low methionine, low RUP) and LmHr (low methionine, high RUP) were formulated to meet the estimated individual AA requirement except for methionine. Diets HmLr and LmLr contained 35% RUP, and diets HmHr and LmHr contained 43% RUP. Digestion of DM, OM, and NDF was not affected (P>.05) by treatments. Tyrosine, cystine, and threonine ranked as the most resistant AA to microbial fermentation, whereas methionine and lysine ranked among the most degradable. In general, microbial degradation of individual AA followed the same pattern as CP degradation, being higher in diets HmLr and LmLr and lower in diets HmHr and LmHr. Because true microbial digestion of methionine, cystine, tyrosine, and isoleucine was reduced in the presence of high levels of methionine, we concluded that supplementation of dietary methionine could increase flows of these amino acids to the duodenum.

Amino Acids↗
PubMed1999

Effects of type of carbohydrate supplementation to lush pasture on microbial fermentation in continuous culture.

Eight single-flow continuous culture fermenters were used to study the effects of the type of energy source on ruminal N utilization from high quality pasture. The four dietary treatments included high quality grass and legume pasture alone (50:50; wt/wt), pasture plus soybean hulls, pasture plus beet pulp, and pasture plus corn. Diets supplemented with additional sources of energy (soybean hulls, beet pulp, and corn) were isocaloric but differed in the type and rate of carbohydrate fermentation. Energy supplements constituted 45% of the total dietary dry matter and were fed twice daily at 12-h intervals in place of pasture, which is characteristic of grain feeding at milking when animals are in a grazing situation. Energy supplementation reduced pH, NH3 N flow, and NH3 N concentration and increased bacterial N flow (as a percentage of N intake). The supplementation of corn and soybean hulls resulted in the highest microbial N flow (as a percentage of N intake). Corn had a tendency to reduce fiber digestion because of excessively low NH3 N concentrations. Beet pulp was similar to corn in that it decreased NH3 N concentrations. Supplementation of soybean hulls resulted in a more synchronized fermentation, greater volatile fatty acid production, and greater fiber digestion. Nitrogen utilization by microbes was maximized by supplementation with soybean hulls or corn twice a day. With diets based on pasture, it may be more important to improve bacterial N flow and bacterial utilization of N than to maximize the efficiency of bacterial protein synthesis because better utilization of N by ruminal microorganisms results in higher bacterial N flow and higher fiber digestion.

Ammonia↗
PubMed1998

[Costs of sevoflurane in the perioperative setting].

The total costs for a department of anaesthesia amount to a fraction of the total hospital budget that is proportional to the overall number of hospital departments; this means anaesthetic departments are in general not cost drivers. In the analysis of perioperative costs, anaesthesia accounts for about 10-15% of the total costs for the complete hospital stay, the exact proportion depending on the type of surgery. In the analysis of costs for the intraoperative period alone anaesthesia personnel contributes about 20%, and material costs about 10% of the total costs, while inhalational agents account for less than 1%. Aggregating the cost for inhalational agents, about 5% of the total budget of an anaesthesia department are accounted for by volatile agents, which take a 20% share of all drug costs in an anaesthesia department. When the costs of one MAC-hour of anaesthesia are compared, halothane, enflurane and isoflurane remain the cheapest agents. Sevoflurane is less expensive than desflurane at current market prices. However, at low fresh gas flows the price difference for one MAC-hour is marginal for these volatile anaesthetics. Total intravenous anaesthesia using propofol is even more expensive, more than 2- to 6-fold the costs of inhalational anaesthesia, depending on the dosage of the intravenous agent, the type of inhalational agent, the fresh gas flow, etc. In our hospital, overall costs for inhalational agents could be reduced over a three year period by increasing use of the low-flow technique, despite sevoflurane becoming the agent of choice for pediatric and ambulatory patients and for operations of short duration. An overall cost-effectiveness analysis must balance the costs of the various agents and the pharmacodynamic advantages of the new agents, e.g. rapid recovery from anaesthesia. Furthermore, indirect costs for side effects have to be taken into account, e.g., nausea and vomiting. The question of whether these effects and side effects translate into cost differences between agents depends largely on local factors, e.g., patient case mix, staffing, policy of discharge from the postanaesthetic care unit, and many others. We conclude that volatile anaesthetics account for only a minor portion of the budgets in the anaesthesia department and the hospital overall. The higher market price for the new agents that result in higher costs per MAC-hour may be compensated for by the economic impact of the fewer side effects and the shorter postanaesthesia stay in the hospital.

Anesthesia Department, Hospital↗