Short-term influence of Cu, Zn, Ni and Cd excess on metabolism, ultrastructure and distribution of elements in lichen Xanthoria parietina (L.) Th. Fr.

Lichens are symbiotic organisms that are very sensitive to heavy metal pollution. However, there is little evidence of how heavy metal pollution affects the physiological status, ultrastructural changes and distribution of elements in the layers of lichen thalli. For this purpose we simulated metal pollution to lichens and studied its impact on Xanthoria parietina. Thalli were treated with the heavy metals Cu, Zn, Ni, Cd in the form of sulfates at concentrations of 100µM and 500µM during 24, 48 and 72h. Untreated lichens served as controls. We assessed the status of physiological parameters (fluorescence and integrity of chlorophyll a, content of soluble proteins and ergosterol), ultrastructural changes, especially to the photobiont, and the distribution of elements in the layers of thalli in relation to treatment with heavy metals. We found positive correlations between the content of all tested heavy metals and the physiological response. We assessed the toxicity of the selected metals as follows: Cd >= Cu >= Ni > Zn, based on the effects on the photobiont layer in the lichen thallus and physiological measurements.

Correlation between thymidylate synthase gene variants, RNA and protein levels in primary colorectal adenocarcinomas.

This study was designed to compare thymidylate synthase (TS) genotype, mRNA and protein levels in primary colorectal adenocarcinoma, and to examine the correlation between microsatellite instability (MSI) and TS expression. The TS genotype of 68 patients with colorectal cancer was determined by polymerase chain reaction (PCR) and restriction fragment length polymorphism analysis in peripheral blood mononuclear cells and tumour tissue. The TS mRNA levels in tumour tissue were measured by reverse-transcription PCR, and TS protein levels and MSI status were assessed using immunohistochemistry. Significantly higher mRNA and protein levels were observed in patients with the TS 3R/3R versus the 2R/2R and 2R/3R genotypes. There was no correlation between TS single nucleotide polymorphism and TS expression. Individuals homozygous for the six base-pair insertion in the 3'-untranslated region had significantly higher TS mRNA levels than heterozygous and homozygous wild type individuals. The TS mRNA and protein levels were significantly higher in microsatellite unstable tumours compared with microsatellite stable tumours. There was a significant association between the number of TS enhancer region repeats (in blood) and intratumoural TS mRNA and protein levels. A larger case series investigating the role of TS gene polymorphisms as predictors of sensitivity to 5-fluorouracil-based chemotherapy is required.

Microarray analysis of placental tissue in intrauterine growth restriction.

OBJECTIVE: Besides foetal or maternal disorders, placental dysfunction is a major cause of intrauterine growth restriction (IUGR). Although numerous macro- and histopathological changes have been described, little is known about the precise aetiology and the contribution of foetal/placental genes in this disorder. DESIGN: Placental tissues of 20 IUGR and control neonates were analysed by microarray technique. Four of the regulated genes with possible relevance in the pathogenesis of IUGR and its consequences were further studied in placentas of 27 IUGR and 35 control newborns. RESULTS: Elevated gene expression of leptin, corticotrophin-releasing hormone (CRH), and IGF-binding protein-1 (IGFBP-1) in IUGR placentas could be confirmed in the larger group by real-time PCR, whereas prolactin showed no significant difference. Accordingly, protein expression of leptin and IGFBP-1 depicted by Western blot was elevated in IUGR, prolactin was not different. Birthweight standard deviation score (SDS) correlated negatively to leptin, IGFBP-1, and CRH, whereas placental weight correlated only to IGFBP-1. Leptin correlated negatively to gestational age of IUGR patients and positively to placental score, a marker of severity of impaired foeto-placental circulation. CONCLUSIONS: As confirmed in a large group of IUGR and control samples, the up-regulated factors leptin, IGFBP-1, and CRH may serve as candidate genes for the prediction of subsequent metabolic consequences in IUGR newborns. These three factors may not only influence growth of the foetus, but might also interact with programming of its metabolic functions, which has to be determined in an ongoing study.

[An unusual breast tumor]. / Ein ungewöhnlicher Mammatumor.

The presented case shows how difficult it can be to diagnose rare diseases if they present with masses in atypical locations. In an extensive further diagnostic workup other characteristic findings then point to the correct diagnosis.

Preparing pure photon number states of the radiation field

The quantum mechanical description of a radiation field is based on states that are characterized by the number of photons in a particular mode; the most basic quantum states are those with fixed photon number, usually referred to as number (or Fock) states. Although Fock states of vibrational motion can be observed readily in ion traps, number states of the radiation field are very fragile and difficult to produce and maintain. Single photons in multi-mode fields have been generated using the technique of photon pairs. But in order to generate these states in a cavity, the mode in question must have minimal losses; moreover, additional sources of photon number fluctuations, such as the thermal field, must be eliminated. Here we observe the build-up of number states in a high-Q cavity, by investigating the interaction dynamics of a probe atom with the field. We employ a dynamical method of number state preparation that involves state reduction of highly excited atoms in a cavity, with a photon lifetime as high as 0.2 seconds. (This set-up is usually known as the one-atom maser or 'micromaser'.) Pure states containing up to two photons are measured unambiguously.