Factors determining microbial colonization of liquid nitrogen storage tanks used for archiving biological samples

The availability of bioresources is a precondition for life science research, medical applications, and diagnostics, but requires a dedicated quality management to guarantee reliable and safe storage. Anecdotal reports of bacterial isolates and sample contamination indicate that organisms may persist in liquid nitrogen (LN) storage tanks. To evaluate the safety status of cryocollections, we systematically screened organisms in the LN phase and in ice layers covering inner surfaces of storage tanks maintained in different biobanking facilities. We applied a culture-independent approach combining cell detection by epifluorescence microscopy with the amplification of group-specific marker genes and high-throughput sequencing of bacterial ribosomal genes. In the LN phase, neither cells nor bacterial 16S rRNA gene copy numbers were detectable (detection limit, 10² cells per ml, 10³ gene copies per ml). In several cases, small numbers of bacteria of up to 10⁴ cells per ml and up to 10⁶ gene copies per ml, as well as Mycoplasma, or fungi were detected in the ice phase formed underneath the lids or accumulated at the bottom. The bacteria most likely originated from the stored materials themselves (Elizabethingia, Janthibacterium), the technical environment (Pseudomonas, Acinetobacter, Methylobacterium), or the human microbiome (Bacteroides, Streptococcus, Staphylococcus). In single cases, bacteria, Mycoplasma, fungi, and human cells were detected in the debris at the bottom of the storage tanks. In conclusion, the limited microbial load of the ice phase and in the debris of storage tanks can be effectively avoided by minimizing ice formation and by employing hermetically sealed sample containers.

Coping with stress in medical students: results of a randomized controlled trial using a mindfulness-based stress prevention training (MediMind) in Germany

BACKGROUND

High prevalence rates of psychological distress in medical training and later professional life indicate a need for prevention. Different types of intervention were shown to have good effects, but little is known about the relative efficacy of different types of stress management interventions, and methodological limitations have been reported. In order to overcome some of these limitations, the present study aimed at evaluating the effect of a specifically developed mindfulness-based stress prevention training for medical students (MediMind) on measures of distress, coping and psychological morbidity.

METHODS

We report on a prospective randomized controlled trial with three study conditions: experimental treatment (MediMind), standard treatment (Autogenic Training) and a control group without treatment. The sample consisted of medical or dental students in the second or eighth semester. They completed self-report questionnaires at baseline, after the training and at one year follow-up. Distress (Trier Inventory for the Assessment of Chronic Stress, TICS) was assessed as the primary outcome and coping (Brief COPE) as a co-primary outcome. Effects on the psychological morbidity (Brief Symptom Inventory, BSI) as a secondary outcome were expected one year after the trainings.

RESULTS

Initially, N = 183 students were randomly allocated to the study groups. At one year follow-up N = 80 could be included into the per-protocol analysis: MediMind (n =31), Autogenic Training (n = 32) and control group (n = 17). A selective drop-out for students who suffered more often from psychological symptoms was detected (p = .020). MANCOVA's on TICS and Brief COPE revealed no significant interaction effects. On the BSI, a significant overall interaction effect became apparent (p = .002, η2partial = .382), but post hoc analyses were not significant. Means of the Global Severity Index (BSI) indicated that MediMind may contribute to a decrease in psychological morbidity.

CONCLUSION

Due to the high and selective dropout rates, the results cannot be generalized and further research is necessary. Since the participation rate of the trainings was high, a need for further prevention programs is indicated. The study gives important suggestions on further implementation and evaluation of stress prevention in medical schools.

TRIAL REGISTRATION

This trial is recorded at German Clinical Trials Register under the number DRKS00005354 (08.11.2013).

Efficient sweat reduction of three different antiperspirant application forms during stress-induced sweating

OBJECTIVES

Stress sweating can occur in everyday situations independently of thermally-induced perspiration. It is triggered by emotionally challenging situations and leads to underarm wetness and a characteristic unpleasant malodor. In this study, we aimed to determine the long-term efficacy of three unperfumed antiperspirant (AP) formulas for different application forms (roll-on, stick, aerosol) against stress-induced sweating and malodor formation.

METHODS

We utilized the widely accepted Trier Social Stress Test (TSST) to induce psychosocial stress in female and male volunteers (18 - 40 years) and determined physiological stress parameters. To additionally assess the efficacy of the test AP roll-on against thermally-induced sweating, a hot room study was performed.

RESULTS

Increasing heart rates and an augmentation of saliva cortisol levels during the TSST indicated a substantial stress reaction which was paralleled by a pronounced sweat production in the untreated axillae of both males and females. Forty-eight hours after application, all three test APs significantly decreased the amount of sweat in the treated axillae independent of gender. With respect to AP effects on malodor production, trained sniffers assessed sweat samples collected during the TSST from the untreated axillae as significantly more malodorous than comparable samples from the AP-treated axillae. Also, independent of gender the test AP roll-on significantly decreased the thermally-induced sweat in the AP-treated axilla.

CONCLUSION

We show for the first time a highly effective reduction of emotionally-induced axillary sweating and malodor production for three different application forms 48 h after the last product use. The specially developed roll-on, stick, and aerosol AP provide long-term protection against stress-induced sweat which is of high relevance in everyday life.

Observation of large scissors resonance strength in actinides

The orbital M1 scissors resonance has been measured for the first time in the quasicontinuum of actinides. Particle-γ coincidences are recorded with deuteron and (3)He-induced reactions on (232)Th. The residual nuclei (231,232,233)Th and (232,233) Pa show an unexpectedly strong integrated strength of B(M1)=11-15μ(n)(2) in the E(γ)=1.0-3.5 MeV region. The increased γ-decay probability in actinides due to scissors resonance is important for cross-section calculations for future fuel cycles of fast nuclear reactors and may also have an impact on stellar nucleosynthesis.

Temporally resolved plasma composition measurements by collective Thomson scattering in TEXTOR (invited)

Fusion plasma composition measurements by collective Thomson scattering (CTS) were demonstrated in recent proof-of-principle measurements in TEXTOR [S. B. Korsholm et al., Phys. Rev. Lett. 106, 165004 (2011)]. Such measurements rely on the ability to resolve and interpret ion cyclotron structure in CTS spectra. Here, we extend these techniques to enable temporally resolved plasma composition measurements by CTS in TEXTOR, and we discuss the prospect for such measurements with newly installed hardware upgrades for the CTS system on ASDEX Upgrade.

The mammalian gene function resource: the International Knockout Mouse Consortium

In 2007, the International Knockout Mouse Consortium (IKMC) made the ambitious promise to generate mutations in virtually every protein-coding gene of the mouse genome in a concerted worldwide action. Now, 5 years later, the IKMC members have developed high-throughput gene trapping and, in particular, gene-targeting pipelines and generated more than 17,400 mutant murine embryonic stem (ES) cell clones and more than 1,700 mutant mouse strains, most of them conditional. A common IKMC web portal (www.knockoutmouse.org) has been established, allowing easy access to this unparalleled biological resource. The IKMC materials considerably enhance functional gene annotation of the mammalian genome and will have a major impact on future biomedical research.

Measurements of intrinsic ion Bernstein waves in a tokamak by collective Thomson scattering

In this Letter we report measurements of collective Thomson scattering (CTS) spectra with clear signatures of ion Bernstein waves and ion cyclotron motion in tokamak plasmas. The measured spectra are in accordance with theoretical predictions and show clear sensitivity to variation in the density ratio of the main ion species in the plasma. Measurements with this novel diagnostic demonstrate that CTS can be used as a fuel ion ratio diagnostic in burning fusion plasma devices.

Collective Thomson scattering measurements with high frequency resolution at TEXTOR

We discuss the development and first results of a receiver system for the collective Thomson scattering (CTS) diagnostic at TEXTOR with frequency resolution in the megahertz range or better. The improved frequency resolution expands the diagnostic range and utility of CTS measurements in general and is a prerequisite for measurements of ion Bernstein wave signatures in CTS spectra. The first results from the new acquisition system are shown to be consistent with theory and with simultaneous measurements by the standard receiver system.

Development and testing of a fast Fourier transform high dynamic-range spectral diagnostics for millimeter wave characterization

A fast Fourier transform (FFT) based wide range millimeter wave diagnostics for spectral characterization of scattered millimeter waves in plasmas has been successfully brought into operation. The scattered millimeter waves are heterodyne downconverted and directly digitized using a fast analog-digital converter and a compact peripheral component interconnect computer. Frequency spectra are obtained by FFT in the time domain of the intermediate frequency signal. The scattered millimeter waves are generated during high power electron cyclotron resonance heating experiments on the TEXTOR tokamak and demonstrate the performance of the diagnostics and, in particular, the usability of direct digitizing and Fourier transformation of millimeter wave signals. The diagnostics is able to acquire 4 GHz wide spectra of signals in the range of 136-140 GHz. The rate of spectra is tunable and has been tested between 200,000 spectra/s with a frequency resolution of 100 MHz and 120 spectra/s with a frequency resolution of 25 kHz. The respective dynamic ranges are 52 and 88 dB. Major benefits of the new diagnostics are a tunable time and frequency resolution due to postdetection, near-real time processing of the acquired data. This diagnostics has a wider application in astrophysics, earth observation, plasma physics, and molecular spectroscopy for the detection and analysis of millimeter wave radiation, providing high-resolution spectra at high temporal resolution and large dynamic range.

Strong scattering of high power millimeter waves in tokamak plasmas with tearing modes

In tokamak plasmas with a tearing mode, strong scattering of high power millimeter waves, as used for heating and noninductive current drive, is shown to occur. This new wave scattering phenomenon is shown to be related to the passage of the O point of a magnetic island through the high power heating beam. The density determines the detailed phasing of the scattered radiation relative to the O-point passage. The scattering power depends strongly nonlinearly on the heating beam power.

Search for the pygmy dipole resonance in 68Ni at 600 MeV/nucleon

The gamma decay from Coulomb excitation of 68Ni at 600 MeV/nucleon on a Au target was measured using the RISING setup at the fragment separator of GSI. The 68Ni beam was produced by a fragmentation reaction of 86Kr at 900 MeV/nucleon on a 9Be target and selected by the fragment separator. The gamma rays produced at the Au target were measured with HPGe detectors at forward angles and with BaF2 scintillators at backward angles. The measured spectra show a peak centered at approximately 11 MeV, whose intensity can be explained in terms of an enhanced strength of the dipole response function (pygmy resonance). Such pygmy structure has been predicted in this unstable neutron-rich nucleus by theory.

A line-of-sight electron cyclotron emission receiver for electron cyclotron resonance heating feedback control of tearing modes

An electron cyclotron emission (ECE) receiver inside the electron cyclotron resonance heating (ECRH) transmission line has been brought into operation. The ECE is extracted by placing a quartz plate acting as a Fabry-Perot interferometer under an angle inside the electron cyclotron wave (ECW) beam. ECE measurements are obtained during high power ECRH operation. This demonstrates the successful operation of the diagnostic and, in particular, a sufficient suppression of the gyrotron component preventing it from interfering with ECE measurements. When integrated into a feedback system for the control of plasma instabilities this line-of-sight ECE diagnostic removes the need to localize the instabilities in absolute coordinates.

Key pinch in healthy adults: normative values

Intra-individual and inter-individual variations of key pinch strength were analysed in a standardised manner for healthy Caucasian adults (female n = 403; male n = 366) aged between 20 and 95 years. The mean strength was less in women (right 6.6 kg; left 6.1 kg) than in men (right 10.4 kg; left 9.7 kg). Independently of hand dominance or gender, the right side was about 7% stronger. Constitutional variables such as forearm length, forearm circumference and hand size showed a positive correlation with key pinch strength. Since the correlation between age and key pinch was similar in both genders, showing a continuous decrease of strength from the fifth decade of life on, key pinch seems independent from gender-specific hormonal changes. In conclusion, we recommend to side adjust measured values and to include information regarding constitutional characteristics for intra-individual comparison.

Diagnostik von Persönlichkeitsstörungen im Jugendalter nach SKID-II

Zusammenfassung: Fragestellung: Ziel der vorliegenden Untersuchung war eine Überprüfung der Anwendbarkeit des Strukturierten Klinischen Interviews für DSM-IV, Achse II: Persönlichkeitsstörungen (SKID-II) im Jugendalter sowie eine Untersuchung zur Übereinstimmung zwischen SKID-II Diagnosen und klinischem Urteil. Zusätzlich wurde der Frage nachgegangen, welche Faktoren bei Patientinnen einer jugendpsychiatrischen Inanspruchnahmepopulation Persönlichkeitsstörungen (PS) prognostizieren. Methodik: Insgesamt wurden 110 stationär behandelte, jugendpsychiatrische Patienten im Alter von 14-18 Jahren mit dem SKID-II und dem Persönlichkeitsstil- und Störungsinventar (PSSI) untersucht. Ergebnisse: 32.7% der untersuchten Patienten zeigten nach SKID-II die Diagnose einer PS. Die Übereinstimmung zwischen kategorialem Urteil (PS liegt vor versus PS liegt nicht vor) des SKID-II und der klinischen Diagnose erwies sich insgesamt als niedrig. Lediglich für die histrionische PS und für die Borderline-PS ergaben sich annehmbare bis sehr gute Übereinstimmungen. Logistische Regressionsanalysen identifizierten «Anorexia nervosa (bulimisch)», «einfache Aktivitäts- und Aufmerksamkeitsstörung/Störung des Sozialverhaltens (ADHD/SSV)» und «Schicht» als relevante prognostische Faktoren für PS. Schlussfolgerungen: Das SKID-II, das primär für Erwachsene entwickelt wurde, ist für den Gebrauch bei Jugendlichen gut einsetzbar. Im jugendpsychiatrischen Bereich sind die Diagnosen Anorexia nervosa (bulimisch) und ADHD/SSV eng mit der Entwicklung einer PS assoziiert.

Die Beugefähigkeit im Daumengrundgelenk des gesunden Erwachsenen

Metacarpophalangeal flexion of the thumb is known to be highly variable. To obtain normative values, active metacarpophalangeal flexion of the thumb was measured bilaterally in healthy Caucasian adults (female n = 403; male n = 366) in a standardized manner. Independent of gender, inter-individual variation was high, ranging between 16 degrees and 90 degrees and showing a continuous decrease with increasing age. Women showed a bigger range of motion than men but in both range of motion was higher on the left thumb (mean 1.4 degrees in women and mean 1.1 degrees in men). No influence of hand dominance was observed. Thus, the healthy contralateral side should be used as parameter of comparison.

Collapse of the N=28 shell closure in (42)Si

The energies of the excited states in very neutron-rich (42)Si and (41,43)P have been measured using in-beam gamma-ray spectroscopy from the fragmentation of secondary beams of (42,44)S at 39A MeV. The low 2(+) energy of (42)Si, 770(19) keV, together with the level schemes of (41,43)P, provides evidence for the disappearance of the Z=14 and N=28 spherical shell closures, which is ascribed mainly to the action of proton-neutron tensor forces. New shell model calculations indicate that (42)Si is best described as a well-deformed oblate rotor.

Measurement of the sign of the spectroscopic quadrupole moment for the 2(1)+ state in 70Se: no evidence for oblate shape

Using a method whereby molecular and atomic ions are independently selected, an isobarically pure beam of 70Se ions was postaccelerated to an energy of 206 MeV using REX-ISOLDE. Coulomb-excitation yields for states in the beam and target nuclei were deduced by recording deexcitation gamma rays in the highly segmented MINIBALL gamma-ray spectrometer in coincidence with scattered particles in a silicon detector. At these energies, the Coulomb-excitation yield for the first 2+ state is expected to be strongly sensitive to the sign of the spectroscopic quadrupole moment through the nuclear reorientation effect. Experimental evidence is presented here for a prolate shape for the first 2+ state in 70Se, reopening the question over whether there are, as reported earlier, deformed oblate shapes near to the ground state in the light selenium isotopes.

[Influence of intraoperative pupil diameter and nuclear grade due to complications during Aqualase phacoemulsification]

PURPOSE

The aim of this study was to make an evaluation of the frequency of intraoperative complications during Aqualase phacoemulsification and correlate it to different intraoperative pupil diameters and nuclear grades.

METHODS

Aqualase phacoemulsification was performed in 23 eyes without retinal or optic disc pathology in 23 unselected patients (15 women and 8 men) who underwent out-patient cataract surgery. Nuclear grade, intraoperative pupil diameters and complications were recorded. The correlation of intraoperative complications with intraoperative pupil diameter and nuclear grade was determined using "Fisher's exact" test.

RESULTS

The average age of our patients was 70.3 (+/- 12.5) years, the mean best spectacle-corrected visual acuity (BSCVA) preoperatively was 0.39 (+/- 0.15) and the mean BSCVA postoperatively was 0.79 (+/- 0.13). The mean aqua time was 3.11 s (+/- 1.55 s) with maximum nuclear sclerosis of up to grade 3 (mean nuclear sclerosis 1.9). The aqua time correlated with the nuclear sclerosis (r = 0.90). The mean intraoperative pupil diameter was 7.2 (+/- 0.7) mm. In 2 of 3 patients with an intraoperative pupil diameter of 6 mm, iris touch occurred intraoperatively. There were no other intra- or postoperative complications. The frequency of iris touch was statistically significantly higher for reduced pupil diameters (p = 0.01). The nuclear grade with a maximum of 3 was without statistical significance to iris touch frequency (p > 0.05).

CONCLUSIONS

The number of iris traumas is significantly higher when the intraoperative pupil diameter is reduced. The iris should be protected in these cases. A prospective, randomised study should be performed to compare the number of intraoperative complications between ultrasound and Aqualase phacoemulsification.

Brd2/RING3 interacts with a chromatin-binding domain in the Kaposi's Sarcoma-associated herpesvirus latency-associated nuclear antigen 1 (LANA-1) that is required for multiple functions of LANA-1

Latency-associated nuclear antigen 1 (LANA-1) of Kaposi's sarcoma-associated herpesvirus (KSHV) mediates the episomal replication of the KSHV genome, as well as transcriptional regulation, in latently infected cells. Interaction of LANA-1 with cellular chromatin is required for both these functions. An N-terminal heterochromatin-binding site in LANA-1 is essential for the replication and maintenance of latent episomes, as well as transcriptional regulation. We have recently described a C-terminal domain in LANA-1 that modulates the interaction with cellular interphase chromatin or elements of the nuclear matrix. Here, we used a series of LANA-1 deletion mutants to investigate the relationship between the different functions of LANA-1 and its interaction with the host chromatin-binding protein Brd2/RING3. Our findings suggest that the C-terminal chromatin-binding domain in LANA-1 is required for multiple LANA-1 functions, including the ability to bind to and replicate viral episomal DNA, to modulate transcription, and to interact with Brd2/RING3. Similar to the recently described tethering of bovine papillomavirus E2 protein to host chromatin via Brd4/MCAP, Brd2/RING3, another member of the Brd family of chromatin-binding proteins, therefore interacts with a chromatin-binding region of another viral latent nuclear protein and could play a role in its multiple functions.

Tbx20 is essential for cardiac chamber differentiation and repression of Tbx2

Tbx20, a member of the T-box family of transcriptional regulators, shows evolutionary conserved expression in the developing heart. In the mouse, Tbx20 is expressed in the cardiac crescent, then in the endocardium and myocardium of the linear and looped heart tube before it is restricted to the atrioventricular canal and outflow tract in the multi-chambered heart. Here, we show that Tbx20 is required for progression from the linear heart tube to a multi-chambered heart. Mice carrying a targeted mutation of Tbx20 show early embryonic lethality due to hemodynamic failure. A linear heart tube with normal anteroposterior patterning is established in the mutant. The tube does not elongate, indicating a defect in recruitment of mesenchyme from the secondary heart field, even though markers of the secondary heart field are not affected. Furthermore, dorsoventral patterning of the tube, formation of working myocardium, looping, and further differentiation and morphogenesis fail. Instead, Tbx2, Bmp2 and vinexin alpha (Sh3d4), genes normally restricted to regions of primary myocardium and lining endocardium, are ectopically expressed in the linear heart tube of Tbx20 mutant embryos. Because Tbx2 is both necessary and sufficient to repress chamber differentiation (Christoffels et al., 2004a; Harrelson et al., 2004), Tbx20 may ensure progression to a multi-chambered heart by repressing Tbx2 in the myocardial precursor cells of the linear heart tube destined to form the chambers.

Echocardiographic assessment of left ventricular size and function in normal children from infancy to adolescence: acoustic quantification in comparison with traditional echocardiographic techniques

The purpose of this study was to establish normal left ventricular acoustic quantification (AQ) reference values for children from infancy to adolescence and to compare AQ-derived parameters with traditional M-mode and Doppler indices. We studied 150 normal, healthy children aged 2 days to 14 1/2 years. Left ventricular parasternal end diastolic area and left ventricular end diastolic volume calculated by AQ were linearly related to the body surface area to the 1.1 and 1.4 powers. AQ parasternal peak filling rate and atrial fractional area change in the neonatal period were 140% and 142% of the adolescent's values, respectively, and decreased to 110% and 112% by 36 months of age. The duration of the rapid filling phase and the rapid filling contribution, as identified by AQ, was shorter or lower than that measured by the Doppler method. Interobserver variability of AQ parameters ranged from 8.1% for the ejection fraction to 18.2% for the peak filling rate. Manual biplane determinations of volumes were slightly higher than AQ calculations with highly significant correlations (p <0.001). Our data permit the determination of normal ranges of AQ parameters in relation to body surface area or age.

Catecholamines stimulate interleukin-6 synthesis in rat cardiac fibroblasts

Proinflammatory cytokines have been implicated in the pathophysiology of different heart diseases. Recent evidence suggests that interleukin-6 (IL--6) may play a role in mechanisms leading to cardiac hypertrophy. In addition, catecholamines are known to induce cardiac hypertrophy. In the present study, we examined whether cardiac fibroblasts may be a potential source of IL--6 production in the rat heart and whether catecholamines can modulate the IL--6 synthesis. Only a small amount of IL--6 mRNA was detected in unstimulated rat cardiac fibroblasts. However, a 50-fold increase of IL--6 mRNA was found after stimulation with norepinephrine (NE). Addition of carvedilol, a alpha- and beta-adrenergic receptor antagonist, prevented almost completely the NE-induced synthesis of IL--6 mRNA. Phenylephrine, an alpha-adrenergic agonist, and isoproterenol, a beta-adrenergic agonist, also induced an increase in IL--6. However, the stimulation via beta-receptors led to a more pronounced elevation. These data show that NE increases IL--6 expression in rat cardiac fibroblasts and that IL--6 may play an important autocrine/paracrine role in cardiac disease states associated with hypertrophy.

Fibronectin synthesis by activated T lymphocytes: up-regulation of a surface-associated isoform with signalling function

Fibronectin (FN) is a major constituent of the extracellular matrix. We now provide evidence for a surface-associated isoform of FN that is synthesized by T cells upon activation. The T-cell-derived FN has an unusual splice pattern: an additional domain, EDB, is produced whereas sequences within another domain, IIICS, are spliced out. CS1, the binding domain for very late antigen-4 (VLA-4), however, is still generated. To study the potential function of surface-associated FN its synthesis was down-regulated by an antisense oligonucleotide, then proliferation of T cells was induced by cross-linked anti-CD3. Proliferation was reduced as was expression of CD25. Moreover, when T cells were cultured in high density, the synthetic peptide QILDVPST, corresponding to CS1, inhibited proliferation, as did antibodies to VLA-4. We propose that surface-associated FN is a ligand for VLA-4, which by binding to VLA-4 on an adjacent cell, provides a costimulatory signal, thus sustaining T-cell proliferation.

Up-regulation of intracellular calcium, cyclic adenosine monophosphate and fibronectin synthesis in tubuar epithelial cells by complement

The terminal complement complex C5b-9 is known to participate in inflammatory processes including glomerular or tubulointerstitial injury. Injury appears to be a direct consequence of C5b-9-mediated cell stimulation. In that context we studied activation of tubular epithelial cells by C5b-9 particularly with regard to fibronectin synthesis and the transmembrane signals involved. C5b-9 in sublytic concentrations caused a rise of intracellular calcium and of cAMP, followed by an increase in abundance of fibronectin-specific mRNA and accumulation of protein. Stabilized cAMP or increasing the cAMP level by forskolin enhanced fibronectin synthesis with similar kinetics. The effect of cAMP could be enhanced by adding a calcium ionophore. Since the fibronectin gene is known to have a cAMP-responsive element, the data suggest that C5b-9 increases fibronectin synthesis via generation of cAMP.

The vhuU gene encoding a small subunit of a selenium-containing [NiFe]-hydrogenase in Methanococcus voltae appears to be essential for the cell

We developed a general method for the site-specific deletion of gene sequences to obtain new selectable markers in the archaeon Methanococcus voltae. Using a deletion in the hisA gene, a vector was integrated into the chromosome by homologous recombination, thereby reconstituting histidine prototrophy. The vector contained the beta-glucuronidase gene uidA of Escherichia coli as a reporter under the control of an M. voltae promoter that normally drives the expression of a selenium-free [NiFe]-hydrogenase after selenium deprivation. This construct has allowed us to check whether the selenium supply was sufficiently low to induce the transcription of the genes encoding the selenium-free hydrogenases. We tried to introduce a chromosomal deletion of the vhuU gene of the archaeon M. voltae by gene replacement and by keeping the cells under selenium deprivation. The gene vhuU encodes the very small, selenocysteine-containing subunit that is part of the primary reaction center of the Vhu hydrogenase. All transformants bearing the deletion also contained the vhuU wild-type gene. Therefore, the vhuU gene appears to be essential for the cell even under conditions that lead to the induction of the selenium-free homologue Vhc of the Vhu hydrogenase.

Fibronectin synthesis by human tubular epithelial cells in culture: effects of PDGF and TGF-beta on synthesis and splicing

BACKGROUND

Enhanced synthesis of extracellular matrix proteins including fibronectin (FN) is associated with the development of sclerosis. In this context we studied FN synthesis by tubular epithelial cells in response to transforming growth factor-beta (TGF-beta) and platelet-derived growth factor (PDGF).

METHODS

FN protein synthesis by human tubular epithelial cells in culture (TEC) was measured by biosynthetic labeling and ELISA. Splicing of FN was assessed by RT-PCR and by Northern blotting.

RESULTS

Cultivated TEC synthesized and released FN, the majority of which was deposited as an unsoluble protein and a minor portion (10 to 15%) was released into the supernatant. TGF-beta and, to a lesser degree, PDGF, up-regulated FN synthesis. All three FN splice variants (EDA, EDB, and IIICS) were produced. PDGF did not influence the splicing. TGF-beta preferentially up-regulated the EDA splice variant, but had no effect on the splicing of the other domains.

CONCLUSIONS

PDGF and TGF-beta both up-regulate FN synthesis of TEC. TGF-beta, but not PDGF, also changed the quality of the de novo synthesized FN, and thus has a different role in the development of sclerosis.

Expression of the 14 kDa galactose-binding protein, galectin-1, on human tubular epithelial cells

By reverse phase PCR and Northern blotting, RNA of the 14 kDa galactose-binding protein (galectin-1) could be identified in primary cultures of human tubular epithelial cells. To assess protein synthesis and the possible function of galectin-1 on TEC, the cellular proteins were biosyntheticically labeled with [34S]-methionine and absorbed to immobilized laminin. Multiple radiolabeled proteins were eluted, a strong band in the area of 14 kDa was seen, coinciding with the galectin-1 band as identified by Western blotting. Surface expression of galectin-1 was seen by cytofluorometry with two different polyclonal antibodies to galectin-1. These data are in line with the finding that tubular epithelial cells adhere to laminin, partly in a Ca(2+)-independent manner.

Interaction of transforming growth factor beta 1 with human glomerular epithelial cells in culture: opposite effects on synthesis of matrix proteins and on urokinase plasminogen activator

The effect of transforming growth factor-beta (TGF-beta) was analyzed on the synthesis of fibronectin, collagen type IV, and urokinase plasminogen activator in human glomerular epithelial cells in culture. An increase in the abundance of specific mRNA was found for collagen type IV and fibronectin. Fibronectin protein synthesis was also increased in TGF-beta treated cells; most of the de novo synthesized fibronectin was found as an unsoluble protein associated with extracellular matrix. In the same cells the amount of plasminogen activator mRNA was found leading also to a decreased surface expression of urokinase plasminogen activator. The data support the concept that by upregulating matrix protein synthesis and downregulating the plasminogen activator system, TGF-beta favors the development of sclerosis.

Fibronectin modulates interleukin 6 and fibronectin synthesis of human glomerular mesangial cells in culture

In this paper we report that fibronectin (FN) and its proteolytic 120-kD fragment regulate synthesis and secretion of interleukin 6 (IL-6) and of FN by human glomerular mesangial cells. While intact FN and a fragment derived from the heparin-binding domain had no effect on IL-6 secretion, the 120-kD FN fragment containing the cell attachment site stimulated secretion by 40-fold. The same FN fragment reduced FN secretion and the steady state mRNA level by 80%. The intact FN showed only a weak inhibitory effect (+/- 30%); the 30-kD fragment containing the heparin-binding domain had no effect. The effects of the 120-kD FN were inhibited by the peptide RGDS, implying participation of the cell attachment site in signal transduction. An antibody to the alpha-chain of VLA-3 mimicked the effect of the 120-kD FN, whereas an antibody to the alpha-chain of VLA-5 was partly inhibitory. Taken together, the data suggest that FN by interacting with its receptors differentially regulates the protein synthesis of glomerular mesangial cells, promoting IL-6 secretion and inhibiting FN synthesis.

Fibronectin synthesis in tubular epithelial cells: up-regulation of the EDA splice variant by transforming growth factor beta

The influence of transforming growth factor beta 1 (TGF-beta 1) and of dexamethasone on fibronectin (FN) synthesis of human renal tubular epithelial cells in culture (TEC) was studied. Cocultivation with TGF-beta 1 increased the steady state level of FN RNA within 24 to 48 hours. By PCR and Northern blotting it was found that the EDA splice variant of FN was preferentially up-regulated. To quantitate FN protein synthesis, cells were cultivated in the presence of [35S]-methionine and FN was isolated from the cell supernatants, and the cell lysates by adsorption to gelatin-sepharose. In TGF-beta 1 treated cells, a small increase of FN in the cell supernatants was seen (1.7-fold), and a more prominent increase in the cell lysates (4.5-fold). The FN content of the extracellular matrix was also increased in TGF-beta 1 treated cells. Most of the de novo synthesized FN was identified as the EDA-variant of FN. As a further stimulus, dexamethasone was used. Again, an increase of FN-specific mRNA was seen as well as an increased FN protein synthesis. The ratio between FN and EDA-FN, however, was not altered when compared to untreated cells. Thus, an increase in EDA-FN synthesis is obviously stimulus dependent.

Matrix protein synthesis by glomerular mesangial cells in culture: effects of transforming growth factor beta (TGF beta) and platelet-derived growth factor (PDGF) on fibronectin and collagen type IV mRNA

The pathogenesis of glomerular scarring is multifactional; recent evidence suggests that transforming growth factor beta (TGF beta), a pleiotropic cicatricial mediator, may promote mesangial sclerosis by enhancing the production of extracellular matrix proteins. We studied the effect of TGF beta 1 and TFG beta 2 on collagen type IV and fibronectin (FN) synthesis in human glomerular mesangial cells in culture (GMC). Two hours after addition of TGF beta, an up to twofold increase in abundance of collagen type IV mRNA was found, which further increased up to fivefold within 24 h. Addition of cycloheximide did not inhibit the TGF beta effect, but caused by itself an up to twofold increase in the abundance of collagen type IV mRNA after 2 h. Together with collagen mRNA, the mRNA for FN and for platelet-derived growth factor (PDGF) was also enhanced. PDGF was found to enhance abundance of the collagen type IV and fibronectin mRNA in GMC. A neutralizing antibody to PDGF or a PDGF-antisense oligonucleotide partly inhibited the TGF beta-induced increase of collagen type IV mRNA, suggesting that TGF beta can affect the collagen type IV synthesis not only directly but also indirectly via the synthesis of PDGF.

A thymoma as a cause of true ectopic hyperparathyroidism

Ectopic tumoral secretion of authentic PTH is rare, as only four cases have been convincingly documented by demonstrating the presence of PTH messenger ribonucleic acid in tumor tissue. We report the case of a 25-yr-old male with biochemical alterations typical of primary hyperparathyroidism (elevated calcemia and renal tubular reabsorption of calcium, decreased phosphatemia and maximal tubular reabsorption of phosphate, and increased intact PTH serum levels). Extensive cervical exploration did not reveal any abnormally enlarged parathyroid tissue, but excision of a palpable superior retrosternal mass led to the correction of all abnormal biochemical values. Histological analysis showed a predominantly epithelial thymoma, without any detectable parathyroid gland on serial slices. Tumor extracts contained immunoreactive PTH material, with serial dilutions paralleling PTH standards in an immunoradiometric assay. By contrast, immunoreactive PTH-related protein was absent. Furthermore, on Northern blot analysis, there was a PTH messenger ribonucleic acid transcript with a size similar to that found in parathyroid adenoma or hyperplasia. The thymoma epithelial cells stained positively with antiserum against PTH-(1-34), but negatively with antichromogranin-A antiserum. These results support the ectopic production of authentic PTH by a thymoma and indicate a novel tumoral cause of primary hyperparathyroidism.