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Biomedical subjects

R Bornemann

Publications and source records attributed to R Bornemann.

11 recordsLinked to original sources
PubMed2006

A statistical method for estimating the proportion of cases resulting from cross-transmission of multi-resistant pathogens in an intensive care unit.

Multi-resistant bacteria are an increasing challenge for infection control in hospitals and the proportion of patients newly colonized with multi-resistant bacteria during their hospital stay can be used to assess the effectiveness of infection control measures. Current laboratory methods for estimating this require expensive additional tests. We propose an alternative statistical method to estimate the proportion of cases resulting from transmission in a hospital from the distribution of time intervals between subsequent cases. A prerequisite for the application of this method is the existence of records from regular screening of the patients during their hospital stay, usually performed in intensive care units (ICUs). We describe the method and present an example of its application using records of two multi-resistant pathogens collected in an ICU over a three-year period. The estimated proportion of cases resulting from transmission was 0.73 (95% CI: 0.56-0.90) for meticillin-resistant Staphylococcus aureus and 0.45 (95% CI 0.15-0.75) for imipenem-resistant Pseudomonas aeruginosa. The method proposed here can be used for retrospective evaluation of clinical records in order to evaluate the effectiveness of infection control measures in low endemicity settings.

Cross Infection↗
PubMed2006

Continuous-wave solid-state dye laser.

We report the first realization of a cw solid-state dye laser. The laser medium consists of a laser dye (Rhodamine 6G) dissolved in a photopolymer. The UV-cured solution is sandwiched between two DVD substrates. The resonator design was derived from a conventional liquid solvent dye laser geometry. The laser radiation can be tuned from 565 to 615 nm by using a birefringent filter. A pump power of 2 W leads to a cw output power of more than 20 mW.

Journal Article↗
PubMed2004

Substitution treatment of injecting opioid users for prevention of HIV infection.

BACKGROUND: Injecting drug users are vulnerable to infection with HIV and other blood borne viruses as a result of collective use of injecting equipment as well as sexual behaviour. OBJECTIVES: To assess the effect of oral substitution treatment for opioid dependent injecting drug users on rates of HIV infections, and high risk behaviours. SEARCH STRATEGY: Multiple electronic databases were searched. Reference lists of retrieved studies, reviews and conference abstracts were handsearched. SELECTION CRITERIA: Studies were required to consider the incidence of risk behaviours, or the incidence of HIV infection related to substitution treatment of opioid dependence. All types of original studies were considered. DATA COLLECTION AND ANALYSIS: Each potentially relevant study was independently assessed by two reviewers. For studies that met the inclusion criteria, key information was extracted by one reviewer and confirmed by consultation between all four reviewers. MAIN RESULTS: Twenty-eight studies, involving 7900 participants, were included. The majority were not randomised controlled studies. Issues of confounding and bias are discussed. The studies varied in several aspects limiting the extent of quantitative analysis. REVIEWERS' CONCLUSIONS: Oral substitution treatment for opioid-dependent injecting drug users is associated with statistically significant reductions in illicit opioid use, injecting use and sharing of injecting equipment. It is also associated with reductions in the proportion of injecting drug users reporting multiple sex partners or exchanges of sex for drugs or money, but has little effect on condom use. It appears that the reductions in risk behaviours related to drug use do translate into reductions in cases of HIV infection. The lack of data from randomised controlled studies limits the strength of the evidence presented in this review. However, these findings add to the stronger evidence of effectiveness of substitution treatment on drug use, and treatment retention outcomes shown by other systematic reviews. On this basis, the provision of substitution treatment for opioid dependence in countries with emerging HIV and injecting drug use problems as well as in countries with established populations of injecting drug users should be supported.

Administration, Oral↗
PubMed1997

Immunoisolation of hybrid liver support systems by semipermeable membranes.

Immunoisolation of hybrid liver support systems (LSS) utilizing suitable semipermeable membranes as an immune barrier enables neither immunocompetent cytotoxic factors to cause damage to the hepatocytes in the bioreactor nor xenogenic hepatocyte products to cause immunological side effects in patients. To determine the capability of membranes as an immune barrier, 6 flat membranes were investigated: Cuprophan (C-100), cut-off MW 1000, Cuprophan (C-240), cut-off MW 10,000, Polypropylen hydrophilic and hydrophobic (PPhi, PPho), cut-off MW 500,000-1,000,000, Polysulfon (PS), cut-off MW 1,000,000, Polyamid (PA), cut-off beyond MW 1,000,000. The permeability of the membranes to plasma factors and liver protein fractions (LP) was studied by routine biochemical methods and gel electrophoresis. In a second study, pigs (n=7) were immunised by LP after membrane passage. The results showed PA, PS, and PPhi to be completely permeable for plasma factors and LP C-100 and C-240 for urophanic substances, and C-240 again for LP under MW 14.000. All 7 pig sera studied by Western blot discovered pre-formed xenoreactive natural IgG-antibodies (NAB) against human liver antigen (AG) with MW 26.000. AB de-novo-synthesis was demonstrated for AG with MW 45.000. No AB-synthesis was induced for epitopes under MW 26,000. These results suggest that limiting the cut-off of bioreactor outflow membranes to MW < 26,000 could avoid immunological side effects to patients.

Animals↗
PubMed1996

Is a clinical application of hybrid liver support systems limited by an initial disorder in cellular amino acid and alpha-keto acid metabolism, rather than by later gradual loss of primary hepatocyte function?

The in-vitro amino acid (AA) and alpha-keto acid (KA) metabolism of bioreactors initially seeded with 2.5 x 10(9) pig hepatocytes was investigated with a perfusion technique. Considerable changes in the culture medium concentrations of AA and KA were measured during the first days in culture. This is indicative of dynamic cellular metabolism in the initial phase. While the concentration of pyruvate decreased starting on the first day, alpha-ketoglutarate, alpha-ketoisocaproate, alpha-ketoisovalerate, and alpha-keto-beta-methyl-n-valerate were synthesized. The long term use of hepatocyte cultures in bioreactors and thus a desirable clinical hybrid liver support therapy appears to be possible since the hepatocytes switched, after 15 days in culture, to steady-state conditions with a stable amino acid turnover featuring general AA uptake accompanied by KA release. The release of branched chain KA, in particular that of alpha-ketoisocaproate, reflects an effective transamination activity in the bioreactor system. Primary pig hepatocytes cultivated in hybrid liver support systems for therapy of acute liver failure or as devices for bridging to liver transplantation can sustain amino acid metabolism for at least 30 days in vitro. However, an initial disorder following the cell isolation that is demonstrated may limit immediate utilization of the systems prior to the reorganisation of the cells to tissue-like structures in bioreactors.

Amino Acids↗
PubMed1996

["Spoils of war"--losses of the Berlin Veterinary Medicine Library in 1945].

All the German veterinary libraries suffered heavy losses during World War II and its aftermath, but the Berlin Veterinary Faculty, whose library was known until 1945 as the biggest veterinary book collection of the world, was exceedingly affected. The reports on the damage during these years note losses of up to 35,000 or 43,000 of nearly 60,000 books. Actually, diverse papers did mention this fact but they concealed the underlying causes of the losses or simply referred to effects of war. However, new evidence allows to claim, that most of the losses have been caused by a very different measure: the confiscation of parts of the library by units of the Soviet Army in May and June 1945 as spoils of war. Eye witnesses and unpublished official as well as unofficial reports show that the choice as to what books should be seized was purposefully made according to special criteria: the most modern specialists' literature (journals and books) and the rare books of bibliophilic value. The library lost important parts of its stock: medical books, parts of the irreplaceable historical collection in veterinary medicine, the foreign language books, the biggest part of the natural science literature (physics, chemistry, biology with botany and zoology) and books on adjacent fields of interest (geography and travel literature, belles lettres, history, philosophy and so on). This contribution deals with the events during the weeks before and after VE day and the course of measures taken in selecting and expropriating the books mentioned above. It is intended to invite additional contemporary witnesses who might bei knowledgeable about these events to help in specifying them more precisely and clearing open questions, which still remain.

Animals↗
PubMed1996

Consideration of potential immunological problems in the application of xenogenic hybrid liver support.

Hybrid liver support systems (LSS) for the use of pig liver cells are under development for extracorporeal therapy of acute liver failure and for bridging to liver transplantation. A literature overview about possible immunological side effects of a clinical application is given. The data summarised from experimental studies and those clinical applications of porcine cells reported so far, suggest that clinical use of LSS utilising porcine cells and an immuno-isolation membrane should not be compromised by severe immunological complications. The reported data suggest that clinical application should be conducted in conjunction with carefully planned immunological monitoring. Only after such applications of LSS have been carried out and further data have been evaluated, might one be able to judge the immunological consequences of broader application of hybrid liver support.

Animals↗
PubMed1993

Advantages and disadvantages of the alternatives of private practice, public health office and clinic out-patient department as dispensaries for methadone substitution of drug users.

In Germany, methadone substitution will be expanded considerably. Pilot projects and single private practitioners collected first experiences. Other programmes and practitioners follow, since important obstacles have been removed. Instead of individual solutions for limited numbers, broader concepts must be developed. Private practice, public health office and clinic out-patient departments each offer advantages and disadvantages. In several surveyed cities, there are a variety of substitution facilities and no general solution. Local facilities have to be examined for their advantages and disadvantages and should be connected cooperatively--e.g. containing a central out-patient department and a number of private practitioners--to serve the needs of the patients and the efficacy of the system.

Ambulatory Care Facilities↗
PubMed1990

[HIV-1 prevalence in deaths caused by drug overdose in various large cities of West Germany and West Berlin between 1985 and 1988].

The development of the HIV-1-prevalence among drug deaths (n = 753) in several German cities (West Berlin, Frankfurt, Munich, Hamburg, Bremen, Cologne and Stuttgart) from 1985 to 1988 was evaluated; in 1988 43% of 674 deceased drug addicts were examined. The regional prevalence rate was between 15 and 25%; only in Berlin 42% of the drug deaths were HIV-infected (cumulated data of all cities over the 4-year-period: 26%). There was no uniform or steady regional development of HIV-1-prevalence in the different cities. The ratio men/women among drug deaths was 3:1. The HIV-1-prevalence among males was 22%, among females 40%. HIV-infected individuals were 2-3 years older than seronegatives. Predictions concerning the trend of prevalence rates are not possible up to now. Continuous monitoring of the HIV-status of drug deaths seems to be a worthful method to evaluate the spread of this disease among the risk group of intravenous drug addicts.

Acquired Immunodeficiency Syndrome↗