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It was reported previously that low-density lipoproteins (LDL) differentially stimulate cell growth of hormone-responsive (ER+) and hormone-unresponsive (ER-) mammary tumor cell lines. Here we examined the mRNA levels of the LDL-receptor (LDL-R) gene with RNAse protection analysis in ER- (MDA-MB-231 and HBL-100) and ER+ (MCF-7 and ZR75-1) cells, and compared them with the estrogen receptor (ER) status. Measurable amounts of ER mRNA were only found in ER+ cells as expected. LDL-R mRNA abundance was 3-5 fold higher in ER- cells as compared to ER+ cells. Incubation with phorbol-12-myristate-13-acetate led to a significant increase (p < 0.005) of LDL-R mRNA in ER+ cells, whereas in ER- cells LDL-R mRNA levels remained merely unchanged. Incubation of cells with dioctanoylglycerol, a synthetic homolog of diacylglycerol, increased LDL-R mRNA in ER+ but not in ER-. Inhibition of protein kinase C (PKC) by H7 resulted in a highly significant reduction of LDL-R mRNA both in ER+ and ER- cells. PKC seems to be an important regulator of LDL-R mRNA abundance in mammary tumor cells. It is hypothesized that in human-breast cancer the process of conversion from hormone-responsive to hormone-unresponsive status is accompanied by a change in PKC activity and PKC might exert cell specific differences on the regulation of LDL-R mRNA levels, which in turn influences the delivery of exogenous cholesterol to cancer cells.

Free radicals and subsequent lipid peroxidation have been implicated in the pathogenesis of several degenerative and chronic diseases which are also treated frequently in spas. There are some data arising from previous studies which support an antioxidant or scavenging effect of iodide, being the essential ingredient of a therapeutically used local brine. The aim of the study was to test the antioxidant capacity of iodide in human serum. For this reason we measured the so-called Total Antioxidant Status determined by a colorimetric method, which reflects the protection against the attack of reactive oxygen species, including enzymic and non-enzymic antioxidants. Exogenous iodide applied as NaI, shows a significantly increased antioxidant capacity in comparison with NaCl at a concentration of 15 microM, which is quite comparable to the upper range of serum iodide levels achieved through balneo-therapeutical intervention. This result is in accordance with previous results from in vitro depolymerization experiments with hyaluronic acid. The antioxidant effect of 15 microM NaI has been found to be approaching the physiologically relevant concentration of ascorbic acid (50 microM).

In human physiology, iodine is primarily noted for its role in thyroid function and less so for its many extrathyroidal functions, particularly those based on its antioxidant properties. As I − it protects against free radicals and peroxides. This is seen in vitro in decreased depolymerization of hyaluronic acid and increased antioxidant status in human serum, and in vivo in increased antioxidant enzyme activities and decreases of malondialdehyde and peroxides. It could be shown or deduced that balneotherapeutic applications of iodine/iodide have a positive effect on cardiocirculatory diseases, respiratory disorders, some eye diseases (dry eye, cataract, age-related macular degeneration), and other degenerative diseases connected with increased oxidative stress that are also treated by balneotherapy.

Zusammenfassung.Hintergrund: Sowohl eine erhohte UVEinstrahlung als auch Ozon stellen eine Belastung fur die in der Tranenflussigkeit vorhandenen Schutzmechanismen dar. Freie Radikale konnen dabei die im Tranenfilm enthaltenen Proteine, Mucosubstanzen and Lipide zerstoren. Als Folge entsteht das sogenannte ,Trockene Auge".Ziel dieser Studie sollten Untersuchungen zur Frage sein, inwieweit die Anwendung der iodhaltigen Kurmittel Bad Halls den ,Gesamtantioxidativen Status" der TranenflUssigkeit beinflussen konnen.Material and Methoden: 66 unausgewahlte Bad Haller Kurpatienten, mit and ohne Beschwerden des "Trockenen Auges" in der Anamnese, wurden zur Untersuchung herangezogen. Mittels Mikrokapillaren mit einem Fassungsvermogen von 4 µl erfolgte die Tranenabnahme vor Kurbeginn and nach Kurende. Das antioxidative Potential der verschiedenen Tranenflussigkeitsproben wurde photometrisch bestimmt.Ergebnisse: Die Auswertung des antioxidativen Gesamtpotentials von 127 Tranenfliissigkeitsproben ergab einen signifikanten Anstieg von 0,312 nmol/µl am Kuranfang auf 0,831 nmol/µl zum Kurende.Dabei wurde deutlich, dass Kurgaste in allen Altersgruppen einen signifikanten Anstieg des antioxidativen Potentials nach Absolvierung einer Augenkur erreichen.Schlussfolgerungen: Diese Studie zeigte, dass die in Bad Hall angewendete Jodkurbehandlung zur Verbesserung des antioxidativen Schutzmechanismus beitragen kann. Eine Erhohung des natiirlichen antioxidativen Schutzpotentials reduziert die Moglichkeiten fiir den Angriff von freien Radikalen, die eine der Ursachen fur die Entstehung des Syndroms ,Trockenes Auge" sein konnen. Durch eine verbesserte Abwehrkraft des Tranenfilms gegenuber ,,oxidativem Stress" lielle sich das Risiko fur das Auftreten des umweltinduzierten trockenen Auges vermindern, wobei die mogliche Wirkung von Iodidionen als Sauerstoffradikalfanger diskutiert wird.

There is a time-dependent protective influence of iodide against selenite cataract development. It is supposed that the anticataract effect of iodide could be based on direct or indirect antioxidant mechanisms.

Iodine distribution was studied in isolated porcine eyes after iontophoresis using ¹³¹l-labelled solutions and chemical methods. After a 15-min treatment with a therapeutically used iodine brine, the iodine content in the ocular tissues showed the following rank order: cornea > retina > vitreous body > anterior chamber fluid > lens. Replacement of the brine by 0.15 MNal increased the uptake values in a different way, but the same rank order was maintained. The increase was highest in the cornea (5.6-fold) and only about 2-fold in the lens, nevertheless approaching now the level of 10^––4 M, a concentration which was regarded as being optimal for the antioxidant effect of I^––. Among the other eye components, the relatively high iodine enrichment of the retina was remarkable. The data are discussed with respect to a possible protective, antioxidative and OH-scavenging efficacy of I and to previous results in the literature concerning iodine uptake in ocular tissues.