Negligible In Vitro Recovery of Macromolecules from Microdialysis Using 100 kDa Probes and Dextran in Perfusion Fluid.

Microdialysis is applied in neurointensive care to monitor cerebral glucose metabolism. If recoverable, macromolecules may also serve as biomarkers in brain disease and provide clues to their passage across the blood-brain barrier. Our study aimed to investigate the in vitro recovery of human micro- and macromolecules using microdialysis catheters and perfusion fluids approved for clinical use. In vitro microdialysis of a bulk solution containing physiological or supraphysiological concentrations of glucose, lactate, pyruvate, human IgG, serum albumin, and hemoglobin was performed using two different catheters and perfusion fluids. One had a membrane cut-off of 20 kDa and was used with a standard CNS perfusion fluid, and the other had a membrane cut-off of 100 kDa and was perfused with the same solution supplemented with dextran. The flow rate was 0.3 µl/min. We used both push and push-pull methods. Dialysate samples were collected at 2-h intervals for 6 h and analyzed for relative recovery of each substance. The mean relative recovery of glucose, pyruvate, and lactate was > 90% in all but two sets of experiments. In contrast, the relative recovery of human IgG, serum albumin, and hemoglobin from both bulk solutions was below the lower limit of quantification (LLOQ). Using a push-pull method, recovery of human IgG, serum albumin, and hemoglobin from a bulk solution with supraphysiological concentrations were above LLOQ but with low relative recovery (range 0.9%-1.6%). In summary, exchanging the microdialysis setup from a 20 kDa catheter with a standard perfusion fluid for a 100 kDa catheter with a perfusion solution containing dextran did not affect the relative recovery of glucose and its metabolites. However, it did not result in any useful recovery of the investigated macromolecules at physiological levels, either with or without a push-pull pump system.

Measurement of 8-oxo-2'-deoxyguanosine and 8-oxo-2'-deoxyadenosine in DNA and human urine by high performance liquid chromatography-electrospray tandem mass spectrometry.

A method for the determination of 8-oxo-2'-deoxyguanosine and 8-oxo-2'-deoxyadenosine in DNA and urine by High Performance Liquid Chromatography (HPLC)-Tandem Mass Spectrometry is described. For the urine samples there is no sample preparation except for addition of buffer and internal standards followed by redissolvation of precipitate containing 8-oxo-2'-deoxyguanosine and a centrifugation step before the samples are injected onto the HPLC column. The detection limit for 8-oxo-2'-deoxyguanosine and 8-oxo-2'-deoxyadenosine is approximately 0.3 nM corresponding to 7.5 fmol injected. Long runs, that is, > 50 samples, can be analyzed with only minimal loss of sensitivity. The concentrations excreted into urine samples from humans are between 1 and 100 nM for 8-oxo-2'-deoxyguanosine and below 0.3 nM for 8-oxo-2'-deoxyadenosine. In calf thymus DNA levels down to about 1 oxidized guanosine and adenosine per 10(6) unmodified bases can be detected. High levels of 8-oxo-2'-deoxyguanosine were found, 30 per 10(6) 2'-deoxyguanosine, levels of 8-oxo-2'-deoxyadenosine are at or below the detection limit. These findings indicate that High Performance Liquid Chromatography-Tandem Mass Spectrometry is a highly sensitive and specific method for analysis of oxidative DNA modifications in tissue as well as for analysis of excretion of oxidized nucleotides into urine that ensures a minimum artifact formation.

Teenage abortion in Germany: with reference to the legal system in the United States.

PIP: This document compares the legal aspects of induced abortion in the US and Germany with a focus on how each country treats minors who wish to undergo abortion. After a short introduction, the second section describes the legal approach to abortion in the US where women (including minors) have an implicitly recognized constitutional right to abortion until compelling state interest intervenes at a point where the unborn child would be viable outside of the womb. States, however, may permit parents to participate in their daughter's abortion decisions as long as a "judicial bypass procedure" exists to protect the minor's rights. Section 3 describes the situation in Germany, where no constitutional right to abortion exists and where the fetus is protected by the constitution. A minor's right to abortion is determined by the provisions governing whether or not an abortion can be performed, by age limitations, and by the custody rights of the parents. Relevant decisions of the Federal Constitutional Court in 1975 and 1993 are reviewed to show that women have a duty to carry a pregnancy to term unless the woman requests the abortion within 12 weeks of conception and submits to counseling which seeks to protect the fetus (such an abortion would be illegal but immune from prosecution). German court rulings on the competency of minors to render consent are then noted to show that even minors have ultimate responsibility with regard to abortion. Analysis of the legal situation in Germany continues with a look at the personal custody rights of parents and the limitations on those rights imposed by the constitutional rights of the child, by the child's age, and by the child's self-reliance and capacity to assume responsibility. The conclusion contrasts the US and German legal sources of limitation of parental rights over the decisions of minors and the ways each system determines the competency of a minor to make such a decision.^ieng

[Professional freedom and personal protection of elderly employees]. / Berufsfreiheit und Persönlichkeitsschutz älterer Arbeitnehmer.

A whole range of collective bargaining covenants, staff agreements, and employment contracts stipulate age limits which lead to a termination of employment when the employee reaches a certain age (e.g., 55, 60, or 65). In the Federal Republic of Germany, as opposed to the United States, it tends to be overlooked that this in many cases constitutes a form of "age discrimination", thereby hindering the personal development of the employees affected. The author argues that legal age limits should be evaluated in the light of constitutional standards. He arrives at the conclusion that such age limits frequently do not conform with the guarantees provided by Art. 12 of the Grundgesetz ("Basic Law") of the Federal Republic of Germany. This is particularly true when age limits are implemented as a tool of employment policy. One can but hope that the current line of reasoning of the Bundesarbeitsgericht (Federal Labor Court), which allows a broad application of age limits, will receive an impetus in a new direction. This could come about by a decision of the Full Court of the Bundesarbeitsgericht or by legislative action.