A research facility for habitation questions to be built at the German Aerospace Center in Cologne: future challenges of Space medicine

For long term habitation in space and for living on Moon and Mars, many questions still need to be resolved. Such habitation questions include prevention of and rehabilitation from negative effects of weightlessness that are, in many instances, comparable to problems of aging people on Earth as well as of patients during and recovery from long term stays in bed. Therefore the DLR Institute of Aerospace Medicine has designed a concept for a research facility that will make it possible to join space research directly with terrestrial applications. From a strategic point of view, one major emphasis of :envihab is to form a closely interrelated network of scientists and the industry and the public. The project has been in the planning phase for several years. After an international architectural contest, the winning concept was selected in 2007 by a Jury with ESA participation.

A pilot randomized controlled comparison of extended daily dialysis with filtration and continuous veno-venous hemofiltration: fluid removal and hemodynamics

OBJECTIVES

Extended intermittent dialytic techniques are increasingly being reported in the treatment of ARF in the ICU but few randomized controlled trials exist. We compared one such technique to a technique of continuous renal replacement therapy with regard to fluid removal and hemodynamics.

METHODS

Sixteen critically ill patients with ARF were enrolled in a randomized controlled trial at the ICU of a tertiary hospital. We randomized eight patients to three consecutive days of treatment with either Extended Daily Dialysis with filtration (EDDf) or Continuous Veno-Venous Hemofiltration (CVVH) and compared fluid removal and hemodynamics during treatment.

RESULTS

A total of 16.6 liters of fluid were removed during EDDf (830 mL/day over 20 treatment days) compared with 15.4 liters (700 ml/day over 22 treatment days) during CVVH. Median fluid removal per day was 1837 mL in the EDDf group compared with 1410 mL per day in the CVVH group, p=0.674. Median hourly fluid removal rate was 252 mL for EDDf and 128 mL for CVVH (p<0.01). Mean arterial pressure in the EDDf group was lower at two hours after starting treatment (76 mmHg vs. 94 mmHg) in the CVVH group; p= 0.031. There was no significant difference between groups for heart rate, CVP and noradrenaline dose at all time intervals measured.

CONCLUSIONS

Adequate prescribed fluid removal was achieved with both techniques. However, as expected, fluid was removed at a faster rate during EDDf. This was initially associated with a lower blood pressure than during CVVH where blood pressure increased.

Cell proliferation inhibition and antitumor activity of novel alkyl series of diorganotin(IV) compounds

Diorganotin(IV) compounds, R2SnCl2 are often tetrahedral, and structurally resemble the active platinum compounds, i.e. cisplatin, and consequently a large number of such complexes have been tested for antitumor activity. A structural correlation with biological activity for diorganotin(IV) complexes has shown that active species are associated with complexes having Sn-N bonds longer than 2.39 A which in turn determines the formation of a tin-DNA complex. In view of these, a series of diorganotin(IV) dichloride complexes of N-(2-pyridylmethylene)arylamine (nitrogen-chelating ligands) has been synthesized and characterized on the basis of IR, NMR and 119Sn-Mössbauer studies. In the present study, an attempt was made to determine the comparative antiproliferative and antitumor effect of diorganotin(IV) complexes with different alkyl groups [Me2SnCl2.L1 (OTC-1), Et2SnCl2.L2 (OTC-2) and (n)Bu2SnCl2.L2 (OTC-3)]. The present study in human lymphocytes demonstrated that these diorganotin(IV) complexes could block the cell cycle progression and induce sister chromatid exchanges (SCEs) significantly, however, with respect to the induction of chromosome aberrations (CAs) it was very mild. Both the levels of p53 and p16 proteins were raised after diorganotin(IV) treatment and such induction was maximum in the OTC-3 treated samples. The antitumor activity was determined in accordance with the US National Cancer Institute (NCI) standard protocol for primary screening in Dalton's lymphoma that was maintained by serial intraperitoneal transplantation. The T/C (treated/control) value was increased (186% with OTC-3) when diorganotin(IV) was given after transplantation. The data suggest that the OTC-3 has better antiproliferative and antitumor activity and endogenous glutathione level has no influence on the effect of OTC-3.

Monitoring of renal function in cancer patients: an ongoing challenge for clinical practice

BACKGROUND

Renal impairment (RI) has been shown to be one major risk factor in a number of diseases and is associated with a dismal clinical outcome. However, the influence of milder degrees of renal disease is less well defined, particularly not in patients with malignant diseases.

PATIENTS AND METHODS

We analyzed 167 patients with solid tumors and hematological malignancies. Besides disease-specific parameters, serum creatinine, cystatin C and the estimated glomerular filtration rate (eGFR) ['modification of diet in renal disease' equation (MDRD)/Cockcroft-Gault (CG)] were determined. Patients were compared within eGFR, creatinine and cystatin C groups.

RESULTS

The median MDRD, CG, creatinine and cystatin C levels of all patients were 88 ml/min/1.73 m2, 89 ml/min, 1 mg/dl and 0.9 mg/l, respectively. Patients with chronic kidney disease stage 2 still showed normal creatinine and cystatin levels of 1 mg/dl and 1.1 mg/l, respectively, although mild RI was frequent. Those cancer patients with decreased eGFR (MDRD) (<60 ml/min/1.73 m2) had increased odds ratios (ORs) to have more concurrent diagnoses [OR 3.4; 95% confidence interval (CI) 1.5-8.1], a body mass index >24 kg/m2 (OR 2.1; 95% CI 1.0-4.5) and an elevated (> 245 pg/ml) pro-brain natriuretic peptide level (proBNP) (OR 9.2; 95% CI 3.0-28.3).

CONCLUSIONS

These observations suggest that grouping cancer patients according to renal function, especially eGFR, may be one way to determine specific risk groups.

Intracranial infantile hemangiomas associated with PHACE syndrome

BACKGROUND AND PURPOSE

Head and neck infantile hemangiomas are common lesions that are rarely observed in an intracranial location. We report 4 patients with orbital infantile hemangiomas and ipsilateral enhancing intracranial lesions, presumed to be infantile hemangiomas.

METHODS

Imaging studies and medical records of 4 infants with orbital hemangiomas and enhancing intracranial lesions were reviewed. The intracranial lesions were evaluated in terms of their location, signal intensity characteristics, enhancement pattern, and degree of involution following treatment. Additional findings associated with PHACE syndrome were also noted and a literature review of intracranial infantile hemangiomas and PHACE syndrome was also performed.

RESULTS

The intracranial masses were primarily in or adjacent to the internal auditory canal and demonstrated imaging characteristics and treatment response similar to the ipsilateral orbital lesions. Ipsilateral internal carotid artery hypoplasia, ipsilateral cerebellar hemisphere hypoplasia, and/or other head and neck hemangiomas were present in all patients.

CONCLUSION

These cases collectively support the diagnosis of intracranial infantile hemangiomas and suggest a unique radiographic association between PHACE syndrome and intracranial infantile hemangiomas.

Skin tumors among employees of a tar refinery: the current data and their implications

OBJECTIVE

Skin tumors and their preliminary stages may be recognized and compensated as an occupational disease only after exposure to soot, raw paraffin, tar, anthracene, pitch or similar substances. The presented study was carried out in one of the world's largest tar refineries and special attention was paid to the dermatological long-term effects and today's relevance of tar-induced skin lesions.

METHODS

The data were generated by means of a standardized questionnaire based on occupational disease records and dermatological reports that have been carried out on a regular basis retrospectively. Among other things, the localization, the number and type of skin tumor, the date of diagnosis and the histological evaluation, where available, were taken into account.

RESULTS

In a longitudinal analysis from 1946 to 2002, a total of n = 618 employees were examined. Squamous cell carcinomas n = 393, basal cell carcinomas n = 298, keratoacanthomas n = 194 and melanomas n = 6 were diagnosed. Latency periods for keratoacanthomas (median 29.5 years) and squamous cell carcinomas (median 28.0 years) were almost identical and could possibly imply that the pathomechanisms for both types of skin tumor might be comparable. Of the persons diagnosed, the skin tumors were mainly localized in the head region (n = 1,662). A remarkable divergence in the localization and distribution of the lesions was found when compared to the general population, for example the relative susceptibility of the upper lip (n = 67) compared to the lower lip (n = 31) as well as the less sun-exposed forearms (n = 381) compared to the back of the hand (n = 331), being typically preferred sites of squamous cell carcinomas. Furthermore, a discrepancy between the distribution of premalignant nonmelanoma skin tumors and carcinomas on the back of the nose, which is more exposed to the sun (n = 56) and those in the nostrils (n = 89), which are less exposed to the sun, but are in the act of breathing more exposed to tar, could be found.

CONCLUSIONS

Tar-induced skin lesions are still of importance nowadays, which is reflected in the incidence of new cases and in the relapses of skin tumors. As a consequence, intensified measures are necessary, in the form of primary and secondary prevention. In view of the high incidence of malignant skin tumors in the general public, it is urgently necessary to take occupational hazards into consideration as well.

Demonstration of a nanoparticle-based optical diode

We present the operation of an optical device that exhibits diodelike properties based on two adjacent layers of quantum dots (QDs) encased in a fiber-optic jacket. The possibility of a multilayered device is also discussed. A significant change in the emission spectrum of CdSe/ZnS core-shell QDs was observed when excited by the input laser and the fluorescence of other CdSe/ZnS core-shell QDs. The output of the diode can be taken to be either the incoming laser wavelength of light similar to a conventional diode, or the output may be considered to be one of the QD fluorescence wavelengths. Current work has applications in biological fluorescence monitors and sensors as well as in telecommunications applications.

Evolution of filament structures during edge-localized modes in the MAST Tokamak

Edge-localized modes (ELMs) are repetitive instabilities that occur in the outer region of tokamak plasmas. This Letter provides new information on and the implications of the evolution of the filament structures observed during ELMs in the MAST tokamak. The filaments exist for the time over which particles are being released into the scrape off layer. They start off at the plasma edge rotating at the velocity of the pedestal, and then decelerate toroidally and accelerate radially outwards. As the filaments propagate radially they remain aligned with the local magnetic field line.

The LuxR receptor: the sites of interaction with quorum-sensing signals and inhibitors

The function of LuxR homologues as quorum sensors is mediated by the binding of N-acyl-L-homoserine lactone (AHL) signal molecules to the N-terminal receptor site of the proteins. In this study, site-directed mutagenesis was carried out of the amino acid residues comprising the receptor site of LuxR from Vibrio fischeri, and the ability of the L42A, L42S, Y62F, W66F, D79N, W94D, V109D, V109T and M135A LuxR mutant proteins to activate green fluorescent protein expression from a P(luxI) promoter was measured. X-ray crystallographic studies of the LuxR homologue TraR indicated that residues Y53 and W57 form hydrogen bonds to the 1-carbonyl group and the ring carbonyl group, respectively, of the cognate AHL signal. Based on the activity and signal specificity of the LuxR mutant proteins, and on molecular modelling, a model is suggested in which Y62 (corresponding to Y53 in TraR) forms a hydrogen bond with the ring carbonyl group rather than the 1-carbonyl group, while W66 (corresponding to W57 in TraR) forms a hydrogen bond to the 1-carbonyl group. This flips the position of the acyl side chain in the LuxR/signal molecule complex compared to the TraR/signal molecule complex. Halogenated furanones from the marine alga Delisea pulchra and the synthetic signal analogue N-(sulfanylacetyl)-L-homoserine lactone can block quorum sensing. The LuxR mutant proteins were insensitive to inhibition by N-(propylsulfanylacetyl)-L-homoserine lactone. In contrast, the mutations had only a minor effect on the sensitivity of the proteins to halogenated furanones, and the data strongly suggest that these compounds do not compete in a 'classic' way with N-3-oxohexanoyl-L-homoserine lactone for the binding site. Based on modelling and experimental data it is suggested that these compounds bind in a non-agonist fashion.