Ruben Kuon
Heidelberg University
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Featured researches published by Ruben Kuon.
American Journal of Obstetrics and Gynecology | 2010
Ruben Kuon; Shao-Qing Shi; Holger Maul; Christof Sohn; William L. Maner; Robert E. Garfield
OBJECTIVE The purpose of this study was to evaluate cervical changes and delivery at term during pregnancy in rats after various progestin treatments. STUDY DESIGN Pregnant rats were treated by various routes and vehicles with progesterone, 17-alpha-hydroxyprogesterone caproate (17P), R5020, and RU-486. Delivery time was determined and cervical ripening was assessed in vivo by collagen light-induced fluorescence. RESULTS The cervix is rigid in the progesterone injection, 17P, and vaginal R5020 groups vs controls. Vaginal progesterone had no effect. RU-486 treatment softened the cervix during preterm delivery. Only subcutaneous injected progesterone, R5020 (subcutaneous and vaginal), and topical progesterone in sesame and fish oil inhibits delivery. Delivery is not changed by subcutaneous injection of 17P, vaginal progesterone, oral progesterone, and topical progesterone in Replens (Crinone; Columbia Labs, Livingston, NJ). CONCLUSION Inhibition of cervical ripening and delivery by progestins depends on many factors that include their properties, the route of administration, and the vehicle. This study suggests reasons that the present treatments for preterm labor are not efficacious.
Acta Obstetricia et Gynecologica Scandinavica | 2011
Miha Lucovnik; Ruben Kuon; Linda R. Chambliss; William L. Maner; Shao-Qing Shi; Leili Shi; Robert E. Garfield
Current methodologies to assess the process of labor, such as tocodynamometry or intrauterine pressure catheters, fetal fibronectin, cervical length measurement and digital cervical examination, have several major drawbacks. They only measure the onset of labor indirectly and do not detect cellular changes characteristic of true labor. Consequently, their predictive values for term or preterm delivery are poor. Uterine contractions are a result of the electrical activity within the myometrium. Measurement of uterine electromyography (EMG) has been shown to detect contractions as accurately as the currently used methods. In addition, changes in cell excitability and coupling required for effective contractions that lead to delivery are reflected in changes of several EMG parameters. Use of uterine EMG can help to identify patients in true labor better than any other method presently employed in the clinic.
Acta Obstetricia et Gynecologica Scandinavica | 2011
Miha Lucovnik; Ruben Kuon; Linda R. Chambliss; William L. Maner; Shao-Qing Shi; Leili Shi; Robert E. Garfield
Progestin supplementation appears to be a promising approach to both preventing initiation of preterm labor and treating it once it is already established, given the role of progesterone in maintaining pregnancy, as well as support from basic and clinical research. Progesterone and 17α‐hydroxyprogesterone acetate slow the process of cervical ripening, and this is the rationale for prophylactic long‐term progestin supplementation mostly studied so far. However, progesterone (but not 17α‐hydroxyprogesterone acetate) also inhibits myometrial activity even after the cervix has already ripened. Moreover, these effects depend greatly on the vehicle used and the route of administration. Understanding different mechanisms of action, as well as the importance of progestin formulation, vehicle and route of administration, is the key to finding the optimal progestin treatment for prevention of preterm birth.
American Journal of Obstetrics and Gynecology | 2009
Ruben Kuon; Shao-Qing Shi; Holger Maul; Christof Sohn; Leili Shi; Robert E. Garfield
OBJECTIVE The purpose of this study was to determine whether optical methods can estimate cervix function during pregnancy and whether progestins modify this process. STUDY DESIGN Photos of the external cervix of timed-pregnant rats were taken every other day from day 13 until postpartum day 5 after daily treatments with vehicle (controls) or progestin treatments (progesterone, subcutaneously or vaginally; 17-alpha-hydroxyprogesterone caproate [17P] and RU-486 subcutaneously, once on day 16). The surface area of the cervix was estimated from photos. RESULTS The surface area of cervix increases throughout pregnancy and reverses after delivery in controls. In the progesterone subcutaneously or 17P subcutaneously groups, increases in surface area are lower (17P group until day 19 only; P < .05). Vaginal progesterone does not prevent surface area increases. Only the progesterone subcutaneously blocked delivery. RU-486 increases the surface area of the cervix (P < .05) during preterm delivery. CONCLUSION An optical method is useful for quantitative assessment of the cervix and evaluation of agents that modify cervical function.
Computational and Mathematical Methods in Medicine | 2013
Miha Lucovnik; Ruben Kuon; Robert E. Garfield
Parturition involves increasing compliance (ripening) of the uterine cervix and activation of the myometrium. These processes take place in a different time frame. Softening and shortening of the cervix starts in midpregnancy, while myometrial activation occurs relatively close to delivery. Methods currently available to clinicians to assess cervical and myometrial changes are subjective and inaccurate, which often causes misjudgments with potentially adverse consequences. The inability to reliably diagnose true preterm labor leads to unnecessary treatments, missed opportunities to improve neonatal outcome, and inherently biased research of treatments. At term, the likelihood of cesarean delivery depends on labor management, which in turn depends on accurate assessments of cervical change and myometrial contractility. Studies from our group and others show that noninvasive measurements of light-induced fluorescence (LIF) of cervical collagen and uterine electromyography (EMG) objectively detect changes in the composition of the cervix and myometrial preparedness to labor and are more reliable than clinical observations alone. We present a conceptual model of parturition constructed on cervical LIF and uterine EMG studies. We also explore how these methodologies could be helpful with managing patients experiencing preterm contractions and with optimizing labor management protocols aimed to reduce cesarean section.
Geburtshilfe Und Frauenheilkunde | 2018
Bettina Toth; Wolfgang Würfel; Michael K. Bohlmann; Johannes Zschocke; Sabine Rudnik-Schöneborn; F. Nawroth; E Schleußner; Nina Rogenhofer; T. Wischmann; Michael von Wolff; K. Hancke; Sören von Otte; Ruben Kuon; Katharina Feil; Clemens Tempfer
Purpose Official guideline of the German Society of Gynecology and Obstetrics (DGGG), the Austrian Society of Gynecology and Obstetrics (ÖGGG) and the Swiss Society of Gynecology and Obstetrics (SGGG). The aim of this guideline was to standardize the diagnosis and treatment of couples with recurrent miscarriage (RM). Recommendations were based on the current literature and the views of the involved committee members. Methods Based on the current literature, the committee members developed the statements and recommendations of this guideline in a formalized process which included DELPHI rounds and a formal consensus meeting. Recommendations Recommendations for the diagnosis and treatment of patients with RM were compiled based on the international literature. Specific established risk factors such as chromosomal, anatomical, endocrine, hemostatic, psychological, infectious and immunological disorders were taken into consideration.
Transplant Immunology | 2017
Mostafa G. Aly; Li Zhu; Rolf Weimer; Gerhard Opelz; Christian Morath; Ruben Kuon; Mohammed Tohamy; Gamal Saadi; Mona Soliman; Walaa Ibrahim; Volker Daniel
BACKGROUND Vitamin D has shown an immune-modulatory effect in different studies. Vitamin D stimulates Tregs and inhibits Th17 cells. The immune-modulatory role of vitamin D in chronic kidney disease (CKD) and renal transplant patients is unclear. We measured whether different serum levels of vitamin D were associated with an increased or decreased presence of lymphocyte subsets including Treg and Th17 cells in end-stage renal disease (ESRD) and renal transplant recipients. METHODS Eighty-seven renal transplant recipients and 53 end-stage renal disease (ESRD) patients were enrolled in this study. The absolute counts of CD4+ and CD8+ T, CD16+ CD56+ NK, CD19+ B, CD4+ CD25+ CD127- Foxp3+ (Tregs), Helios+ Tregs, CD38+ Tregs, and CD4+ CD17+ (Th17) cells were analyzed in peripheral blood in both patient groups. In addition, serum 25 (OH) D3, 1, 25 (OH)2 D3, IL-6, IL-17, IL-23, and TGF-β1 were measured. The association between lymphocyte subset counts and 1, 25 (OH)2 D3 or 25 (OH) D3 was studied, as was the association between serum IL-6, IL-17, IL-23, or TGF-β1 and 1,25 (OH)2 D3 or 25 (OH) D3. RESULTS Serum 25 (OH) D3 and 1,25 (OH)2 D3 levels were not independently associated with peripheral CD4+ T, CD19+ B, CD16+ CD56+ NK, Treg, or Th17 cell counts. In contrast to serum 25 (OH) D3, serum1, 25 (OH)2 D3 was positively associated with CD8+ T cells counts in renal transplant recipients. CONCLUSION Our findings indicate low utility of serum 25 (OH) D3 and 1, 25 (OH)2 D3 levels in predicting a change in lymphocyte subset counts in ESRD and renal transplant patients.
PLOS ONE | 2017
Li Zhu; Mostafa Aly; H. Wang; Hristos Karakizlis; Rolf Weimer; Christian Morath; Ruben Kuon; Bettina Toth; Gerhard Opelz; Volker Daniel
Background There is evidence that NK-cell reactivity might affect graft outcome in transplant recipients and pregnancy in women. Method NK-cell subsets were determined in whole blood using eight-colour-fluorescence flow cytometry in patients before and after renal transplantation, patients with recurrent miscarriage (RM) and healthy controls (HC). Results Patients late post-transplant (late-Tx) with functioning renal transplants showed abnormally low CD56dimCD16+ NK-cells containing both perforin and granzyme (vs HC p = 0.021) whereas RM patients exhibited abnormally high numbers of these cells (vs HC p = 0.043). CD56dimCD16+perforin+granzyme+ NK-cell counts were strikingly different between the two patient groups (p<0.001). In addition, recipients late-Tx showed abnormally low CD8+ NK-cells (vs HC p<0.001) in contrast to RM patients who showed an abnormal increase (vs HC p = 0.008). CD8+ NK-cell counts were strongly different between the two patient groups (p<0.001). Higher perforin+granzyme+CD56dimCD16+ and CD8+ NK-cells were associated with impaired graft function (p = 0.044, p = 0.032). After in-vitro stimulation, CD56dimCD16+ and CD56brightCD16dim/- NK-cells showed strong upregulation of CD107a and IFNy, whereas the content of perforin decreased dramatically as a consequence of perforin release. Recipients late post-Tx showed less in-vitro perforin release (= less cytotoxicity) than HC (p = 0.037) and lower perforin release was associated with good graft function (r = 0.738, p = 0.037). Notably, we observed strong in-vitro perforin release in 2 of 6 investigated RM patients. When circulating IL10+CD56bright NK-cells were analyzed, female recipients late post-Tx (n = 9) showed significantly higher relative and absolute cell numbers than RM patients (p = 0.002 and p = 0.018, respectively); and high relative and absolute IL10+CD56bright NK-cell numbers in transplant recipients were associated with low serum creatinine (p = 0.004 and p = 0.012) and high glomerular filtration rate (p = 0.011 and p = 0.002, respectively). Female recipients late post-Tx exhibited similar absolute but higher relative numbers of IL10+IFNy- NK-cells than RM patients (p>0.05 and p = 0.016, respectively). Conclusion NK-cells with lower cytotoxicity and immunoregulatory function might contribute to good long-term graft outcome, whereas circulating NK-cells with normal or even increased cytotoxicity and less immunoregulatory capacity are observed in patients with RM.
Archive | 2018
Stephanie Pildner von Steinburg; E Schleußner; Ruben Kuon; Kilian Vomstein; Bettina Toth
Klinische, laborchemische und sonografische Methoden erlauben die fruhe und zuverlassige Diagnose und Beurteilung einer Fruhschwangerschaft. Die serielle Bestimmung des humanen Choriongonadotropins (hCG) gestattet eine Unterscheidung zwischen intakter und gestorter Implantation. Mit der transvaginalen Sonografie konnen Informationen uber den Implantationsort, die Vitalitat des Embryos und das Vorliegen einer Mehrlingsschwangerschaft gewonnen werden. Zudem ermoglicht die sonografische Beurteilung eine weitgehend zuverlassige Bestimmung des Gestationsalters. Unter dem Begriff „Abort“ wird im deutschsprachigen Raum ein (nichtartifizieller) Verlust der Schwangerschaft vor Eintritt der Lebensfahigkeit des Kindes verstanden. Von Bedeutung ist hierbei die Unterscheidung zwischen sporadischen und habituellen Aborten, wobei ein habituelles Abortgeschehen bei 3 oder mehr aufeinanderfolgenden Fehlgeburten vorliegt. Im ersten Kapitelteil wird auf die klinischen Stadien und die vielfaltigen Ursachen von sporadischen Aborten eingegangen, wahrendem der zweite Kapitelteil die habituellen Aborte und ihre Risikofaktoren behandelt.
Archive | 2017
Ruben Kuon; Bettina Toth
Immunologische Veranderungen konnen bei Frauen mit Fehlgeburten identifiziert werden. Es ist jedoch unklar, ob diese Ursache oder Folge der Fehlgeburt sind. Bei der immunologischen Diagnostik werden verschiedene autoimmune und allogene Faktoren betrachtet. Zur immunmodulierenden Therapie werden u.a. Glucocorticoide, Immunglobuline, Granulocyte-Colony Stimulating Factor, Intralipide und TNF-Inhibitoren eingesetzt. Es fehlt bislang eine eindeutige Zuordnung eines diagnostischen Markers zu einer gezielten immunmodulatorischen Therapie.