Impedance spectroscopy for the non-destructive evaluation of in vitro epidermal models.

PURPOSE: Reconstructed human epidermis (RHE) is standardly used for the risk assessment of chemical compounds. However, analysis is dependent on invasive methods such as histological processing or 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) staining. METHODS: As an alternative, we have developed a non-destructive technology to analyze the integrity of epidermal equivalents based on impedance spectroscopy. RHEs were generated and impedance spectra were recorded. from these spectra, we extrapolated electrical characteristics such as the capacitance and the ohmic resistance. Furthermore, the measurable electrical parameters were used to quantify the effects of mechanical and chemical disruption of the epidermal integrity. RESULTS: A fully matured RHE exhibits typical impedance spectra in a frequency ranging between 1 Hz and 100 kHz, which is comparable to the spectra of freshly isolated human epidermal biopsies. We could show that, during RHE maturation, these characteristics change significantly. Thus, capacitance and ohmic resistance can be employed as a criterion for the quality control of skin equivalents. Additionally, our application of impedance spectroscopy reveals sufficient sensitivity to detect a transient decreased ohmic resistance caused by 2-propanol, which is classified as a non-irritant by MTT assays. CONCLUSION: These results indicate that impedance spectroscopy can be employed as a non-destructive complementary method to assess mild irritative effects, which is currently not possible.

[Primal therapy--a clinically confirmed procedure?]. / Primärtherapie--ein klinisch bewährtes Verfahren?

In two legal findings, the courts had to decide whether medical insurance would pay for so-called primal therapy. The courts requested an evaluation as to whether primal therapy is recognized as a scientific therapeutic process. The authors examined the available literature and then came to the conclusion that primal therapy is not a valid therapeutic technique. They further emphasized that primal therapy is not a type of psychoanalytic therapy. In point of fact, primal therapy has seldom been discussed in the scientific psychotherapeutic literature. That is to say, there are no on-going reports of primal therapy's therapeutic results, no statistical studies and no follow-up studies. Most psychotherapists in the Federal Republic of Germany do not utilize so-called primal therapeutic processes, perceiving it as based on questionable theoretical premises and dangerous in practice. Finally, the authors question the efficacy of primal therapy and especially its use by laymen.

[Client centered psychotherapy]. / Gesprächspsychotherapie nach Rogers (GT).

In the discussion concerning which psychotherapeutic methods should come under the auspices of the medical health system in West Germany, the question is raised regarding the client-centered therapy of Carl Rogers. Can it be considered a distinct psychotherapeutic method? A review of the scientific literature dealing with this method shows that it provides neither a theory of mental illness nor a theory of clinical application based on individual cases or specific neurotic disturbances, Therefore it should be categorized as a useful method of communication in the field of psychology and not as a therapeutic method for treating mental illness.

[Behavior therapy]. / Verhaltenstherapie (VT).

In the discussion concerning which psychotherapeutic methods should come under the auspices of the medical health system in West Germany, the question is raised regarding the behavioral therapy. Can it be considered a distinct psychotherapeutic method? A review of the scientific literature in this area shows that "behavioral therapy" includes a conglomerate of therapeutic procedures which have no common basis neither in theory nor in practical application. These therapeutic procedures are usually pragmatic and symptom-orientated, many of them never having been sufficiently tested in experiments or in clinical application. Before behavioral therapy can be inclused as a legitimate therapeutic method, it is necessary first to establish a catalogue of acceptable procedures. Psychologists working as behavioral therapists must be required to go through thorough training in their own special field as well as basid training in the mental health sciences comparable to that of psychotherapists with a medical background.