Publications by authors named "F Strube"

20 Publications

  • Page 1 of 1

Short-term effects of simulated microgravity on morphology and gene expression in human breast cancer cells.

Physiol Int 2019 Dec 3;106(4):311-322. Epub 2020 Jan 3.

Department of Plastic, Aesthetic and Hand Surgery, Otto-von-Guericke-University, Magdeburg, Germany.

Introduction: Microgravity has been shown to impose various effects on breast cancer cells. We exposed human breast cancer cells to simulated microgravity and studied morphology and alterations in gene expression.

Materials And Methods: Human breast cancer cells were exposed to simulated microgravity in a random positioning machine (RPM) for 24 h. Morphology was observed under light microscopy, and gene alteration was studied by qPCR.

Results: After 24 h, formation of three-dimensional structures (spheroids) occurred. BRCA1 expression was significantly increased (1.9×,  < 0.05) in the adherent cells under simulated microgravity compared to the control. Expression of KRAS was significantly decreased (0.6×,  < 0.05) in the adherent cells compared to the control. VCAM1 was significantly upregulated (6.6×, 2.0×,  < 0.05 each) in the adherent cells under simulated microgravity and in the spheroids. VIM expression was significantly downregulated (0.45×, 0.44×,  < 0.05 each) in the adherent cells under simulated microgravity and in the spheroids. There was no significant alteration in the expression of , , , and .

Conclusions: Simulated microgravity induces spheroid formation in human breast cancer cells within 24 h and alters gene expression toward modified adhesion properties, enhanced cell repair, and phenotype preservation. Further insights into the underlying mechanisms could open up the way toward new therapies.
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December 2019

The Role of C-X-C Chemokine Receptor Type 4 (CXCR4) in Cell Adherence and Spheroid Formation of Human Ewing's Sarcoma Cells under Simulated Microgravity.

Int J Mol Sci 2019 Dec 2;20(23). Epub 2019 Dec 2.

Department of Plastic, Aesthetic and Hand Surgery, Otto-von-Guericke-University, Leipziger Strasse 44, D-39120 Magdeburg, Germany.

We studied the behavior of Ewing's Sarcoma cells of the line A673 under simulated microgravity (s-µg). These cells express two prominent markers-the oncogene EWS/FLI1 and the chemokine receptor CXCR4, which is used as a target of treatment in several types of cancer. The cells were exposed to s-µg in a random-positioning machine (RPM) for 24 h in the absence and presence of the CXCR4 inhibitor AMD3100. Then, their morphology and cytoskeleton were examined. The expression of selected mutually interacting genes was measured by qRT-PCR and protein accumulation was determined by western blotting. After 24 h incubation on the RPM, a splitting of the A673 cell population in adherent and spheroid cells was observed. Compared to 1 g control cells, was significantly upregulated in the adherent cells and in the spheroids, while and expression were significantly enhanced in spheroids only. Transcription of was upregulated and and were down-regulated in both, adherent in spheroid cells, respectively. Regarding, protein accumulation EWS/FLI1 was enhanced in adherent cells only, but CD44 decreased in spheroids and adherent cells. Inhibition of CXCR4 did not change spheroid count, or structure. Under s-µg, the tumor marker EWS/FLI1 is intensified, while targeting CXCR4, which influences adhesion proteins, did not affect spheroid formation.
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http://dx.doi.org/10.3390/ijms20236073DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6929163PMC
December 2019

Alteration of Cytoskeleton Morphology and Gene Expression in Human Breast Cancer Cells under Simulated Microgravity.

Cell J 2020 Apr 8;22(1):106-114. Epub 2019 Sep 8.

Department of Plastic, Aesthetic and Hand Surgery, Otto-von-Guericke-University, Magdeburg, Germany.Electronic

Objective: Weightlessness simulation due to the simulated microgravity has been shown to considerably affect behavior of tumor cells. It is aim of this study to evaluate characteristics of human breast cancer cells in this scaffoldfree 3D culture model.

Materials And Methods: In this experimental study, the cells were exposed to simulated microgravity in a randompositioning machine (RPM) for five days. Morphology was observed under phase-contrast and confocal microscopy. Cytofilament staining was performed and changes in expression level of cytofilament genes, proliferation/differentiation genes, oncogenes and tumor suppressor genes were detected by quantitative reverse transcription polymerase chain reaction (qRT-PCR), followed by western blot confirmation.

Results: After five days, distinct spheroid formation was observed. Rearrangement of the cytoskeleton into spherical shape was visible. gene expression was significantly up-regulated for adherent cells and spheroids (3.3x and 3.6x respectively, P<0.05 each). also showed significant gene up-regulation for adherent cells and spheroids (3.2x and 3.9x respectively, P<0.05 each). showed significant gene up-regulation in adherent cells and spheroids (2.1x and 4.1x respectively, P<0.05 each). showed significant gene up-regulation (2.4x, P<0.05) in the spheroids, but not in the adherent cells. showed no significant alteration in gene expression. ) showed significant gene up-regulation in adherent cells and spheroids (3.2x, 3.0x, P<0.05 each). gene expression was down-regulated under simulated microgravity, without significance. Alterations of gene expressions could be confirmed on protein level for vimentin and MAPK1. Protein production was not increased for BRCA1, human epidermal growth factor receptor 2 (HER2) and VEGF. Contradictory changes were determined for and its related protein.

Conclusion: Microgravity provides an easy-to handle, scaffold-free 3D-culture model for human breast cancer cells. There were considerable changes in morphology, cytoskeleton shape and gene expressions. Identification of the underlying mechanisms could provide new therapeutic options.
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http://dx.doi.org/10.22074/cellj.2020.6537DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6791064PMC
April 2020

Apoptosis Induction and Alteration of Cell Adherence in Human Lung Cancer Cells under Simulated Microgravity.

Int J Mol Sci 2019 Jul 23;20(14). Epub 2019 Jul 23.

Department of Plastic, Aesthetic and Hand Surgery, Otto-von-Guericke-University, Leipziger Strasse 44, D-39120 Magdeburg, Germany.

Background: Lung cancer cells are known to change proliferation and migration under simulated microgravity. In this study, we sought to evaluate cell adherence, apoptosis, cytoskeleton arrangement, and gene expression under simulated microgravity.

Methods: Human lung cancer cells were exposed to simulated microgravity in a random-positioning machine (RPM). Cell morphology and adherence were observed under phase-contrast microscopy, cytoskeleton staining was performed, apoptosis rate was determined, and changes in gene and protein expression were detected by real-time PCR with western blot confirmation.

Results: Three-dimensional (3D)-spheroid formation was observed under simulated microgravity. Cell viability was not impaired. Actin filaments showed a shift in alignment from longitudinal to spherical. Apoptosis rate was significantly increased in the spheroids compared to the control. , , and gene expression was significantly upregulated in the adherent cells under simulated microgravity with an increase in corresponding protein production for p14 and RB1. expression was significantly upregulated in the adherent cells, but protein was not. Gene expressions of , and remained unaltered.

Conclusion: Simulated microgravity induces alteration in cell adherence, increases apoptosis rate, and leads to upregulation of tumor suppressor genes in human lung cancer cells.
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http://dx.doi.org/10.3390/ijms20143601DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6678991PMC
July 2019

Caregiver Reports of Screen Time Use of Children with Autism Spectrum Disorder: A Qualitative Study.

Behav Sci (Basel) 2019 May 22;9(5). Epub 2019 May 22.

Faculty II-Criminal Sciences, Police University of Applied Sciences, 78054 Villingen-Schwenningen, Germany.

Screen based media have progressively become an integral part in the daily lives of children and youths with and without autism spectrum disorder (ASD). However, research that exclusively pursues the functionality of screen media use of children with ASD is extremely rare. Through a triangulated approach, the present study aims to fill this gap. We conducted 13 interviews with parents of children with ASD and supplemented this interview-study with an online survey including parents of children with ASD (n = 327). Children with ASD mostly used screen media (especially television) for their wellbeing, which is associated with chances and risks. Based on the parental interviews it is suggested that the media usage of children with ASD should be supervised. The results are discussed in terms of their practical implementation.
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http://dx.doi.org/10.3390/bs9050056DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6562753PMC
May 2019

Strain Elastography as a New Method for Assessing Pelvic Floor Biomechanics.

Ultrasound Med Biol 2017 04 17;43(4):868-872. Epub 2017 Jan 17.

Department of Obstetrics and Gynecology, University of Münster, Münster, Germany.

Strain elastography (SE) is a new technique of parametric imaging that allows quantification of the elasticity of tissue. The aim of our study was to determine if the elasticity of para-urethral tissue correlates with urethral mobility and urinary incontinence (UI). Ninety-nine unselected women were investigated with SE. They were given a standardized interview about UI, and SE raw data for the para-urethral tissue were acquired in a sagittal standard urethra-symphysis view while being stimulated by a coughing fit. We placed one region of interest (ROI A) in the tissue between the urethra and vagina at midlevel of the urethra bordering the urethral wall. The second ROI (ROI B) was set at the level of the os urethra internum in the tissue of the bladder neck in one line to ROI A. We measured elasticity in both ROIs with TDI-Q (Tissue Doppler Imaging-Quantification Software) and calculated the ratio between ROI A and ROI B (A/B). Mobility of the urethra was quantified by measuring the angle between a line parallel to the urethra and a line parallel to the bladder neck during stress and rest. SE analysis was feasible in all cases. A/B was found to be correlated with the incidence of urethral mobility (p < 0.001). The incidence of UI was associated with an increase in urethral mobility (p = 0.04). No correlation between UI and A/B could be shown (p = 0.24). We observed a correlation between urethral mobility and elasticity of the para-urethral tissue. In case of increasing urethral mobility, the para-urethral tissue close to the bladder neck seems to be more elastic, and the patients reported about more symptoms of UI. No noticeable correlation between UI and urethral elasticity was shown. SE may be a useful technique for direct quantification of tissue elasticity and assessment of pelvic floor biomechanics.
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http://dx.doi.org/10.1016/j.ultrasmedbio.2016.12.004DOI Listing
April 2017

Importance of Transvaginal Elastography in the Diagnosis of Uterine Fibroids and Adenomyosis.

Ultraschall Med 2016 Aug 14;37(4):373-8. Epub 2015 Aug 14.

Department of Obstetrics and Gynecology, University Hospital of Münster, Germany.

Purpose: To evaluate normal uterine tissue with special regard to age and the presence of uterine fibroids and adenomyosis with transvaginal elastography.

Materials And Methods: In a prospective study elastographic data of the uterus were obtained in 206 unselected women with transvaginal ultrasound. Women who presented without any uterine pathology in ultrasonography were included in a control group, women with uterine fibroids in a uterine fibroid group, and women with adenomyosis in an adenomyosis group. In the control group strain values were measured at two regions of interest (ROIs) placed one upon the other in the anterior inferior uterine segment during a cycle of compression. The maximum strain ratio (ROI1 / ROI2) was stored as the "age index". In all groups strain values were measured at two ROIs placed side by side in a uterine fibroid (uterine fibroid group) or adenomyosis (adenomyosis group) or healthy homogeneous tissue (control group) and adjacent healthy tissue. Maximum strain ratios (ROI3 / ROI4) were stored as the "lesion index".

Results: The "age index" was significantly negatively correlated with the age of the women (r = -0.49, p < 0.001). The median "lesion indices" were significantly (p < 0.001) different between the uterine fibroid, adenomyosis and control groups. Median "lesion indices" were 2.65, 0.44 and 1.19, respectively.

Conclusion: The "age index" shows that normal uterine tissue has a certain age-dependent stiffness that increases with age. The "lesion index" allows for the assessment of the presence of a uterine fibroid or adenomyosis and helps to differentiate between both focal findings. Thus the use of elastography in addition to conventional ultrasound could help to diagnose uterine focal lesions and may be useful in preoperative planning.
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http://dx.doi.org/10.1055/s-0035-1553266DOI Listing
August 2016

Transforming growth factor β1 and extracellular matrix protease expression in the uterosacral ligaments of patients with and without pelvic organ prolapse.

Female Pelvic Med Reconstr Surg 2015 Jan-Feb;21(1):53-8

From the *Department of Obstetrics and Gynecology and Women's Health, Albert Einstein College of Medicine and Montefiore Medical Center; †Department of Molecular Pharmacology, Albert Einstein Cancer Center, Albert Einstein College of Medicine; ‡Department of Pathology, Albert Einstein College of Medicine and Montefiore Medical Center; and §Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY.

Objectives: This study was undertaken to evaluate the expression of transforming growth factor β1 (TGF-β1) and matrix metalloproteinase 9 (MMP-9), key regulators of the extracellular matrix composition, in the uterosacral ligaments (USLs) of women with pelvic organ prolapse (POP) compared with controls.

Methods: Under an institutional review board approval, USL samples were obtained from women undergoing vaginal hysterectomy for stage 2 or greater POP (cases, n = 21) and from women without POP undergoing vaginal hysterectomy for benign indications (controls, n = 19). Hematoxylin and eosin and trichrome staining were performed on the USL sections, and the distribution of smooth muscle and fibrous tissue were quantified. Immunohistochemical staining was performed using anti-TGF-β1 and anti-MMP-9 antibodies. The expressions of TGF-β1 and MMP-9 were evaluated by the pathologist, who was blinded to all clinical data.

Results: Transforming growth factor β1 expression positively correlated with MMP-9 expression (R = 0.4, P = 0.01). The expressions of TGF-β1 and MMP-9 were similar in subjects with POP versus controls. There was a significant increase in fibrous tissue (P = 0.008) and a corresponding decrease in smooth muscle (P = 0.03), associated with increasing age. The TGF-β1 expression, but not MMP-9 expression, also significantly increased with age (P = 0.02).

Discussion: Although our study uncovered age-related alterations in USL composition and TGF-β1 expression, there was no difference in the expression of TGF-β1 or MMP-9 in the subjects with POP versus controls.
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http://dx.doi.org/10.1097/SPV.0000000000000130DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4344824PMC
February 2016

Ultrafast Z → E photoisomerisation of structurally modified furylfulgides.

Phys Chem Chem Phys 2014 Sep;16(36):19556-63

Institut für Physikalische Chemie, Christian-Albrechts-Universität zu Kiel, Olshausenstr. 40, D-24098 Kiel, Germany.

Femtosecond broadband transient absorption spectroscopy has been used in a comparative study of the ultrafast photo-induced Z → E isomerisation reactions of four photochromic furylfulgides with selected structural motifs in n-hexane as solvent. The results show that all studied Z-fulgides exhibit fast and direct processes along barrierless excited-state pathways involving a conical intersection (CI) between the S1 and S0 electronic states. The excited-state lifetimes range from τ1 = 0.18 ps for the methyl derivative to τ1 = 0.32 ps for the benzofurylfulgide. The impulsive rise of the absorption by vibrationally hot Z- and E-isomers back in the electronic ground state following electronic deactivation and isomerisation indicates that the initially prepared wave packet persists even after passage of the CI. Furthermore, the results provide qualitative evidence for a quickly dephasing vibrational coherence in the electronic ground state. In contrast to the significant changes observed for the corresponding E- and C-isomers [Renth et al., Int. Rev. Phys. Chem., 2013, 32, 1-38], the excited-state dynamics of the Z-isomers is not affected by varied sterical hindrance from methyl and isopropyl substituents at the central hexatriene unit, or by intramolecular bridging, and remains unaltered upon extension of the π-electron system in a benzannulated furyl fulgide.
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http://dx.doi.org/10.1039/c4cp01739kDOI Listing
September 2014

Electronic and steric effects on the photo-induced C→E ring-opening of structurally modified furylfulgides.

Phys Chem Chem Phys 2011 Sep 28;13(34):15699-707. Epub 2011 Jul 28.

Institut für Physikalische Chemie, Christian-Albrechts-Universität zu Kiel, Olshausenstr. 40, D-24098 Kiel, Germany.

The ultrafast C→E ring-opening reactions of four selectively modified furylfulgides have been studied by means of ultrafast broadband transient absorption spectroscopy after femtosecond laser excitation at λ = 500 nm. A large difference in the dynamics was found in the case of benzannulation at the furyl moiety as an example for an electronic effect by extension of the conjugated π-electron system compared to furylfulgides carrying sterically different alkyl substituents at the central cyclohexadiene (CHD) ring. The measured very similar spectro-temporal absorption maps for the furylfulgides with a methyl or isopropyl group at the CHD ring or an intramolecular alkyl bridge from the CHD to the furyl moiety showed two distinctive excited-state absorptions with slightly different decay times. The first time constant (τ(1) = 0.39-0.57 ps) was assigned to the rapid departure of the excited wavepacket from the Franck-Condon region. The slightly longer second decay time of τ(2) = 0.66-0.92 ps, depending on the compound, was attributed to the electronic deactivation and ring-opening through a conical intersection to the S(0) state. In contrast, the benzannulation at the furyl moiety was found to lead to a bi-phasic excited-state decay with τ(2) = 4.7 ps and a much slower additional contribution of τ(3) = 17.4 ps, ≈25 times longer compared to the normal furylfulgides. The drastic change is attributed to a trapping of excited molecules in a local potential energy minimum en route to the conical intersection.
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http://dx.doi.org/10.1039/c1cp21320bDOI Listing
September 2011

Enlarging perineal endometrioma developing after colpoperineorrhaphy.

Int Urogynecol J 2011 Oct 24;22(10):1325-7. Epub 2011 Mar 24.

Department of Obstetrics and Gynecology, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, NY, USA.

Although endometriosis is not infrequent, the occurrence of perineal endometriomata is relatively rare and is generally attributed to seeding of endometrial cells to the perineal body during obstetrical trauma. A 45-year-old female with a history of a colpoperineorrhaphy during menses and a remote history of obstetric perineal trauma presented with an enlarging perineal mass. Excision of the mass led to a clinical and histopathologic diagnosis of perineal endometriosis. Elective surgery disrupting the vaginoperineal epithelium performed during menses may facilitate the seeding of endometrial cells to the perineal body and formation of perineal endometriomata.
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http://dx.doi.org/10.1007/s00192-011-1387-2DOI Listing
October 2011

Tuning of switching properties and excited-state dynamics of fulgides by structural modifications.

Phys Chem Chem Phys 2011 Mar 5;13(9):3800-8. Epub 2011 Jan 5.

Institut für Physikalische Chemie, Christian-Albrechts-Universität zu Kiel, Olshausenstr. 40, D-24098 Kiel, Germany.

The ultrafast photo-induced dynamics of the E-isomers of four selected photochromic fulgides with distinct structural motifs have been elucidated by femtosecond broadband transient absorption spectroscopy in n-hexane as solvent. E→C and E→Z isomerisations, respectively, with time constants of ∼0.12 ± 0.02 ps and ∼0.34 ± 0.03 ps taking place in parallel were found for derivatives with a methyl substituent at the central hexatriene (HT) unit. In contrast, fulgides with increased steric constraints by an iso-propyl substituent or by intramolecular bridging displayed virtually zero E→Z isomerisation, but instead a desired accelerated and more efficient ring closure in a reaction time of only ∼50 ± 10 fs. Both photoisomerisations appear to follow excited-state pathways with distinctive conical intersections. For the ring closure, direct barrierless pathways with steep downhill gradients are likely. Furthermore, the results indicate conformer-specific reactions, with ring closure exclusively by the E(α) conformer and E→Z isomerisation predominantly by the E(β) conformer, because the E(α)→Z channel is unfavoured by the faster and kinetically more competitive E(α)→C reaction. DFT calculations of the equilibrium structures showed that the sterically demanding groups at the HT unit shift the conformer equilibria towards the E(α) conformers. At the same time, they appear to cause a favourable pre-orientation of the furyl unit that accelerates the conrotatory ring closure in the E(α)→C reaction. Benzo-annulation of the furyl unit has little effect on the observed dynamics. Overall, the results demonstrate how the excited-state dynamics and thereby the photoswitching properties of fulgides can be successfully tuned and improved by structural modifications at the chromophores.
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http://dx.doi.org/10.1039/c0cp01890bDOI Listing
March 2011

Rotationally-hindered furyl fulgides.

Acta Crystallogr C 2011 Jan 9;67(Pt 1):o33-6. Epub 2010 Dec 9.

Organische Chemie I, Fakultät für Chemie, Universität Bielefeld, Postfach 100131, D-33501 Bielefeld, Germany.

Fulgides are a representative class of photochromic organic molecules which exhibit several interesting properties for diverse applications in fields such as data storage or high-resolution spectroscopy. The crystal structures of three furyl fulgides with different steric constraints were determined and for two of the compounds both the E and Z isomer structures were defined. The compounds are 3-[(E)-1,3-dimethyl-4,5,6,7-tetrahydro-2-benzofuran-4-ylidene]-4-isopropylidenetetrahydrofuran-2,5-dione, C(17)H(18)O(4), (I-E), 3-[(E)-1,3-dimethyl-5,6,7,8-tetrahydro-4H-cyclohepta[c]furan-4-ylidene]-4-isopropylidenetetrahydrofuran-2,5-dione, C(18)H(20)O(4), (II-E), and the Z isomer, (II-Z), and 3-isopropylidene-4-[(E)-1-(5-methoxy-2-methyl-1-benzofuran-3-yl)ethylidene]tetrahydrofuran-2,5-dione, C(19)H(18)O(5), (III-E), with two molecules in the asymmetric unit, and the Z isomer, (III-Z). The structures of the E and Z isomers show only little differences in the bond lengths and angles inside the hexatriene unit. Because of the strained geometry there are deviations in the torsion angles. Furthermore, small differences in the distances between the bond-forming C atoms in the electrocyclization process give no explanation for the unequal photochromic behaviour.
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http://dx.doi.org/10.1107/S0108270110049401DOI Listing
January 2011

[Trigger digits].

Chir Main 2011 Feb 23;30(1):1-10. Epub 2010 Oct 23.

Groupe Main Provence, clinique Axium, 42 avenue du Maréchal-de-Lattre-de-Tassigny, Aix-en-Provence, France.

Trigger finger is an entity seen commonly by hand surgeons. It is produced by a size mismatch between the flexor tendon and the A1 pulley, which causes pain, clicking, catching, and loss of motion of the affected finger. The diagnosis is usually easy but other pathological processes (extensor apparatus instability, locked metacarpo-phalangeal joint) must be excluded. Treatment modalities in trigger finger include splinting, corticosteroid injection and/or surgery. Indication depends on the clinical form of trigger finger.
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http://dx.doi.org/10.1016/j.main.2010.10.004DOI Listing
February 2011

Effects of oral, vaginal, and transdermal hormonal contraception on serum levels of coenzyme q(10), vitamin e, and total antioxidant activity.

Obstet Gynecol Int 2010 9;2010. Epub 2010 Aug 9.

Department of Obstetrics and Gynecology, Bronx-Lebanon Hospital Center, Albert Einstein College of Medicine, 1650 Grand Concourse, Bronx, NY 10457, USA.

The use of the transdermal contraceptive patch is associated with greater bioavailability of ethinyl estradiol (EE) compared with contraceptive vaginal ring or oral contraceptives (OC). We compared the influences of three contraceptive methods (OC, vaginal ring, and transdermal patch) on serum levels of coenzyme Q(10), alpha-tocopherol, gamma-tocopherol and total antioxidant capacity in premenopausal women. Blood samples from 30 premenopausal women who used hormonal contraception for at least 4 months were collected. Forty subjects who did not use any contraception were studied as control. Serum levels of coenzyme Q(10), alpha-tocopherol and gamma-tocopherol were measured by high-pressure liquid chromatography. Serum samples were also assayed for total antioxidant capacity (TAOC). Serum levels of coenzyme Q(10) and alpha-tocopherol were found to be significantly lower (P < .05) in all three contraceptive users compared with controls. Contraceptive patch users had the lowest levels of coenzyme Q(10) levels compared with normal subjects. Serum TAOC levels were significantly lower (P < .05) among the contraceptive user groups. Alterations in coenzyme Q(10) and alpha-tocopherol induced by hormonal contraception and the potential effect(s) of exogenous ovarian hormones should be taken into consideration in future antioxidant research.
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http://dx.doi.org/10.1155/2010/925635DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2929620PMC
July 2011

Photocyclizable resorcin[4]arene dimers.

Photochem Photobiol Sci 2008 Dec 6;7(12):1457-62. Epub 2008 Aug 6.

Organische Chemie I, Universität Bielefeld, Postfach 100131, 33501, Bielefeld, Germany.

The synthesis of covalently linked dimers, containing two resorcin[4]arene moieties connected over two 9,10-functionalized anthracene units, is reported. Besides the synthetic route, which involves for example the formation of anthracene-9,10-dialkanols ( and ), and characterization of the compounds, the photochemical properties, introduced through the anthracene groups, were investigated by means of UV/VIS spectroscopy. Both resorcin[4]arene dimers ( and ) were able to undergo an intramolecular [4+4] cycloaddition, therefore changing the size of the inner cavity. Unfortunately, the back reaction, which was expected to take place on irradiation below 300 nm or upon heating, was not observed yet and will be the focus of our future work.
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http://dx.doi.org/10.1039/b807700bDOI Listing
December 2008

Regulation of nitric oxide (NO) production by plant nitrate reductase in vivo and in vitro.

J Exp Bot 2002 Jan;53(366):103-10

Forschungszentrum Jülich GmbH, Institut für Biologie des Stoffaustauschs, 52425 Jülich, Germany.

NO (nitric oxide) production from sunflower plants (Helianthus annuus L.), detached spinach leaves (Spinacia oleracea L.), desalted spinach leaf extracts or commercial maize (Zea mays L.) leaf nitrate reductase (NR, EC 1.6.6.1) was continuously followed as NO emission into the gas phase by chemiluminescence detection, and its response to post-translational NR modulation was examined in vitro and in vivo. NR (purified or in crude extracts) in vitro produced NO at saturating NADH and nitrite concentrations at about 1% of its nitrate reduction capacity. The K(m) for nitrite was relatively high (100 microM) compared to nitrite concentrations in illuminated leaves (10 microM). NO production was competitively inhibited by physiological nitrate concentrations (K(i)=50 microM). Importantly, inactivation of NR in crude extracts by protein phosphorylation with MgATP in the presence of a protein phosphatase inhibitor also inhibited NO production. Nitrate-fertilized plants or leaves emitted NO into purified air. The NO emission was lower in the dark than in the light, but was generally only a small fraction of the total NR activity in the tissue (about 0.01-0.1%). In order to check for a modulation of NO production in vivo, NR was artificially activated by treatments such as anoxia, feeding uncouplers or AICAR (a cell permeant 5'-AMP analogue). Under all these conditions, leaves were accumulating nitrite to concentrations exceeding those in normal illuminated leaves up to 100-fold, and NO production was drastically increased especially in the dark. NO production by leaf extracts or intact leaves was unaffected by nitric oxide synthase inhibitors. It is concluded that in non-elicited leaves NO is produced in variable quantities by NR depending on the total NR activity, the NR activation state and the cytosolic nitrite and nitrate concentration.
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January 2002

A plasma membrane-bound enzyme of tobacco roots catalyses the formation of nitric oxide from nitrite.

Planta 2001 Apr;212(5-6):835-41

Institut für Botanik, Technische Universität, Schnittspahnstrasse 10, 64287 Darmstadt, Germany.

Purified plasma membranes (PMs) of tobacco (Nicotiana tabacum L. cv. Samsun) roots exhibited a nitrite-reducing enzyme activity that resulted in nitric oxide (NO) formation. This enzyme activity was not detected in soluble protein fractions or in PM vesicles of leaves. At the pH optimum of pH 6.0, nitrite was reduced to NO with reduced cytochrome c as electron donor at a rate comparable to the nitrate-reducing activity of root-specific succinate-dependent PM-bound nitrate reductase (PM-NR). The hitherto unknown PM-bound nitrite: NO-reductase (NI-NOR) was insensitive to cyanide and anti-NR IgG and thereby proven to be different from PM-NR. Furthermore, PM-NR and NI-NOR were separated by gel-filtration chromatography and apparent molecular masses of 310 kDa for NI-NOR and 200 kDa for PM-NR were estimated. The PM-associated NI-NOR may reduce the apoplastic nitrite produced by PM-NR in vivo and may play a role in nitrate signalling via NO formation.
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http://dx.doi.org/10.1007/s004250000447DOI Listing
April 2001

The isolated scapho-trapezio-trapezoid ligament injury. Diagnosis and surgical treatment in four cases.

J Hand Surg Br 1993 Dec;18(6):730-5

Department of Orthopaedic and Reconstructive Surgery, Bobigny, France.

Isolated injuries of the scapho-trapezial ligament complex are not well recognized. The ligament complex comprises the stout scapho-trapezial ligament, the floor of the flexor carpi radialis (FCR) tendon sheath and the scapho-capitate ligament. Between August 1991 and May 1992, we diagnosed and treated four cases of partial chronic post-traumatic lesions of this ligament complex. There was chronic pain at the base of the thenar eminence and instability of the thumb-index-middle finger pinch. Standard X-rays were normal. The diagnosis of ligament rupture was confirmed by mid-carpal arthrography showing filling of the sheath of FCR tendon. Surgical exploration showed complete rupture of the tendon sheath of FCR in two cases, associated in the other two cases with complete rupture of the scapho-trapezial ligament. Direct repair of the ligamentous elements was performed in all cases. The tendon of FCR was sutured to the tubercle of scaphoid to protect and to reinforce the ligament repair. The patients have been followed-up for between 6 and 12 months. All four patients recovered normal pinch strength to the middle finger. One patient suffered from chronic pain at work.
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http://dx.doi.org/10.1016/0266-7681(93)90232-5DOI Listing
December 1993

[Isolated severe anterolateral scapho-trapezo-trapezoid luxation. Diagnosis and surgical treatment in four cases].

Chirurgie 1993-1994;119(9):530-4

Service de Chirurgie orthopédique et réparatrice, Hôpital Avicenne, Bobigny.

Isolated injuries of the scapho-trapezial ligament complex are not well recognized. The ligament complex comprises the stout scapho-trapezial ligament, the floor of the flexor carpi radialis (FCR) tendon sheath and the scapho-capitate ligament. Between August 1991 and May 1992, we diagnosed and treated four cases of partial chronic post-traumatic lesions of this ligament complex. There was chronic pain at the base of the thenar eminence and instability of the thumb-index-middle finger pinch. Standard X-rays were normal. The diagnosis of ligament rupture was confirmed by mid-carpal arthrography showing filling of the sheath of FCR tendon. Surgical exploration showed complete rupture of the tendon sheath of FCR in two cases, associated in the other two cases with complete rupture of the scaphotrapezial ligament. Direct repair of the ligamentous elements was performed in all cases. The tendon of FCR was sutured to the tubercle of scaphoid to protect and to reinforce the ligament repair. The patients have been followed-up for between 6 and 12 months. All four patients recovered normal pinch strength to the middle finger. One patient suffered from chronic pain at work.
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June 1995