Oxytocin at physiological concentrations evokes adrenocorticotropin (ACTH) release from corticotrophs by increasing intracellular free calcium mobilized mainly from intracellular stores. Oxytocin displays synergistic or additive effects on ACTH-releasing factor or arginine vasopressin-induced ACTH secretion, respectively

The potency of oxytocin (OT) in evoking ACTH secretion by isolated, superfused rat adenohypophyseal corticotrophs and its enhancement by CRF and arginine vasopressin (AVP) were analyzed. Each secretagogue effectively released ACTH from adenohypophyseal cells when added separately in pulsatile fashion in physiological concentrations based on hypophyseal portal blood (OT, 10 nM; AVP, 0.5 nM; CRF, 0.1 nM). OT released ACTH at concentrations as low as 1 nM. Moreover, a dose- response relationship up to 10 microM was revealed. Combinations of a constant amount of CRF (0.1 nM) with increasing concentrations of OT exerted a synergistic effect on ACTH release. In contrast, OT given in various concentrations in combination with AVP (0.5 nM) produced an additive effect on ACTH release. To study the mechanism of action of OT on ACTH secretion, cytosolic free calcium levels in single pituitary cells exposed to OT or AVP were measured using the calcium-sensitive fluorescent indicator Fura-2. Corticotrophs among mixed adenohypophyseal cell types in the primary cultures were identified by immunocytochemistry. More than 500 cells were individually stimulated with OT or AVP. Basal cytosolic free calcium levels ranged between 80- 130 nM free calcium. The addition of 100 nM OT or 1 microM AVP increased the cytosolic free calcium concentration within 3 sec to values ranging from 500-800 nM. An increase in intracellular calcium ranging from 200-500 nM due to OT could still be observed after extracellular calcium depletion. Taken together, our data demonstrate that physiological concentrations of OT stimulate ACTH secretion, independent of the other ACTH secretagogues, by mobilizing calcium mainly from intracellular stores

Remote sensing of aquatic plants

Various sensors were tested in terms of their ability to detect and discriminate among noxious aquatic macrophytes. A survey of researchers currently studying the problem and a brief summary of their work is included. Results indicated that the sensor types best suited to assessment of the aquatic environment are color, color infrared, and black-and-white infrared film, which furnish consistently high contrasts between aquatic plants and their surroundings

PSR B1828-11: a precession pulsar torqued by a quark planet?

The pulsar PSR B1828-11 has long-term, highly periodic and correlated variations in both pulse shape and the rate of slow-down. This phenomenon may provide evidence for precession of the pulsar as suggested previously within the framework of free precession as well as forced one. On a presumption of forced precession, we propose a quark planet model to this precession henomenon instead, in which the pulsar is torqued by a quark planet. We construct this model by constraining mass of the pulsar ($M_{\rm psr}$), mass of the planet ($M_{\rm pl}$) and orbital radius of the planet ($r_{\rm pl}$). Five aspects are considered: derived relation between $M_{\rm psr}$ and $r_{\rm pl}$, movement of the pulsar around the center of mass, ratio of $M_{\rm psr}$ and $M_{\rm pl}$, gravitational wave radiation timescale of the planetary system, and death-line criterion. We also calculate the range of precession period derivative and gravitational wave strength (at earth) permitted by the model. Under reasonable parameters, the observed phenomenon can be understood by a pulsar ($10^{-4}\sim10^{-1}M_{\odot}$) with a quark planet ($10^{-8}\sim10^{-3}M_{\odot}$) orbiting it. According to the calculations presented, the pulsar would be a quark star because of its low mass, which might eject a lump of quark matter (to become a planet around) during its birth.Comment: 6 pages, 3 figures, accepted by MNRAS (Letters

Comment on evidence for new interference phenomena in the decay D+ -> K- pi+ mu+ nu

The experimental determination of low energy pi K scattering phase shifts would assist in determining scattering lengths as well as low energy constants of chiral perturbation theory for which sum rules have been constructed. The FOCUS collaboration has presented evidence for interference pheomena from their analysis of D_l4 decays based on decay amplitudes suitable for a cascade decay D -> K* -> K pi. We point out that if the well-known full five body kinematics are taken into account, pi K scattering phases may be extracted. We also point out that other distributions considered in the context of K_l4 decays can be applied to charm meson decays to provide constraints on violation of |Delta I|=1/2 rule and T-violation.Comment: 9 pages, plain latex; version with minor changes compared to v1 on lepton masses effects, sign error eliminated, clarifying remarks added, one additional ref.; version to appear in Phys. Lett.

Effect of oxytocin on free intracellular Ca2+ levels and progesterone release by human granulosa-lutein cells

Oxytocin and its receptor are found in the corpus luteum in a variety of species, including the human. In the present study we used fura-2 microfluorimetry to investigate whether activation of the oxytocin receptor of cultured human granulosa-lutein cells causes intracellular calcium (Ca2+) signals and affects progesterone release. Although after 1 day in culture, cells were not responsive to oxytocin, the number of responsive cells increased steadily during the first 3 days in culture, reaching a maximum on days 4 and 5 (59-66%) and then declined again until day 8. Effective oxytocin concentrations were apparently independent of the culture day, and concentrations as low as 10 nmol/L increased intracellular free Ca2+ levels from 70-140 nmol/L (basal levels) to maximal peak levels of 800 nmol/L. The oxytocin-induced Ca2+ signal was not affected by removal of extracellular Ca2+ with EGTA. Moreover, depletion of intracellular Ca2+ stores by ionomycin treatment rendered the cells unresponsive to oxytocin, pointing also at the intracellular source of the oxytocin-inducible Ca2+ signal. Interestingly, after one single stimulation with oxytocin, cells became refractory to additional stimuli, and only extremely high concentrations of oxytocin induced a second increase in intracellular free Ca2+. To examine the possible effects of oxytocin on progesterone release by cultured cells, we incubated cells on culture day 2 (20% responsive cells in the fura measurements) and culture day 5 (66% responsive cells in the fura measurements) for 24 h with oxytocin (10 nmol/L) and hCG (10,000 IU/L). Although hCG significantly stimulated progesterone release, oxytocin alone was without a stimulatory effect on either day. However, a significant augmentation of the effect of hCG on progesterone release was found in incubations of cells on day 5. Interestingly, the effects of hCG also included stimulation of oxytocin release by cultured granulosa-lutein cells into the culture medium, as determined by RIA. In summary, our data indicate the presence of a functional oxytocin receptor on human granulosa-lutein cells that is linked to Ca2+ as a second messenger released from intracellular Ca2+ stores. The number of oxytocin-responsive cells increases during differentiation in culture. Moreover, oxytocin release induced by hCG and a stimulatory effect of oxytocin on the hCG-induced progesterone production during the period of maximal responsiveness of cultured cells were found. We, therefore, propose that oxytocin may have autocrine and/or paracrine functions in human granulosa-lutein cells, including fine-tuning of progesterone release

РАЗЛИЧИЕ РАКА ТОЛСТОЙ И ПРЯМОЙ КИШКИ С ТОЧКИ ЗРЕНИЯ ЭПИДЕМИОЛОГИИ, КАНЦЕРОГЕНЕЗА, МОЛЕКУЛЯРНОЙ БИОЛОГИИ, ПЕРВИЧНОЙ И ВТОРИЧНОЙ ПРОФИЛАКТИКИ: ДОКЛИНИЧЕСКИЕ ИССЛЕДОВАНИЯ

Introduction. Colon and rectal cancer (CC, RC) are different entities from a clinical and tumor biological point of view. Up to now, both, CC and RC, are synonymously called  “Colorectal Cancer” (CRC). With our experience in basic and clinical research and routine  work in this field we now have come to the opinion, that the term “CRC” should definitely be questioned, and if justified, be abandoned.Materials/Methods. We analyzed the actual available data from the literature and our own  results from the Ulm based study group FOGT to proof or reject our hypothesis.Results. The following evident differences were recognized: Anatomically, the risk to  develop RC is 4× higher than for CC. Molecular changes in carcinogenesis in CC are different from RC. Physical activity helps to prevent CC, not RC. Pathologically there are differences between RC and CC. In addition, there are also major clinical differences  between CC and RC, such as in surgical topography and– procedures, multimodal treatment  (MMT) approaches (RC in MMT is less sensitive to chemotherapy than CC), and prognostic  factors for the spontaneous course and for success of MMT (e.g. TS or DPD ). Discussion. CC ´sand RC´s definitely are different in parameters of causal and formal carcinogenesis, effectivity of primary prevention by physical activity, conventional and  molecular pathology.According to our findings we can demand from the preclinical point of  view that CC and RC are two different tumor entities in terms of various representative  biological characteristics.CC and RC are also differing substantially in many clinical features, as outlined in a separate paper from our group.Conclusion. “CRC” should no longer be used in basic and clinical research and other fields  of cancer classification as a single disease entity. CC is not the same as RC. CC might even be divided into right and left CC.Введение. Рак толстой и прямой кишки – разные опухоли с клинической и биологической точек зрения. В  настоящее время рак толстой и прямой кишки синонимично называют колоректальным раком. Основываясь  на нашем опыте в фундаментальных и клинических исследованиях в этой области, мы пришли к выводу, что  термин «колоректальный рак» необходимо пересмотреть, его нельзя использовать как обобщающее понятие.Материал и методы. Были проанализировали данные литературы и собственные результаты исследований, чтобы доказать или отклонить эту гипотезу.Результаты. Выявлены следующие очевидные различия: риск развития рака прямой кишки в 4 раза выше,  чем рака толстой кишки; молекулярный канцерогенез при раке толстой кишки отличается от рака прямой  кишки; физическая активность помогает предотвратить рак толстой кишки, но не прямой кишки;  существуют патогистологические различия между раком прямой и толстой кишки. Кроме того, имеются  значительные клинические отличия между этими злокачественными новообразованиями, такие как  различная хирургическая топография и объемы операций, разные показания для назначения  комбинированного лечения, поскольку рак прямой кишки менее чувствителен к химиотерапии, чем рак  толстой кишки, и отличаются прогностические факторы эффективности мультимодальной терапии  (например, тимидилат синтетаза и дигидропиримидин дегидрогеназа).Дискуссия. Рак толстой и прямой кишки определенно различаются по этиологии и формальному  канцерогенезу, эффективности первичной профилактики, связанной с физической активностью, обычной и  по параметрам молекулярной патологии. Согласно нашим данным, можно утверждать, что с доклинической  точки зрения рак толстой и прямой кишки являются двумя разными опухолями, поскольку обладают  различными репрезентативными биологическими характеристиками. Рак толстой и прямой кишки также  существенно различаются по многим клиническим признакам, что было указано в отдельной статье,  представленной нашей исследовательской группой. Заключение. Термин «колоректальный рак» не должен  использоваться в фундаментальных и клинических исследованиях, как определение единого заболевания.  Рак толстой кишки не одно и то же, что и рак прямой кишки. Злокачественные новообразования толстой  кишки могут быть разделены на рак правой и левой половины ободочной кишки

The Rwenzori Mountains, a Paleoproterzoic crustal shear belt crossing the Albertine rift system

This contribution discusses the development of the Paleoproterozoic Buganda-Toro belt in the Rwenzori mountains and its influence on the western part of the East African Rift System in Uganda. The Buganda-Toro belt is composed of several thick-skinned nappes consisting of Archaean Gneisses and Palaeoproterozoic cover units that are thrusted northwards. The high Rwenzori mountains are located in the frontal unit of this belt with retrograde greenschist facies gneisses towards the north, which are unconformably overlain by metasediments and amphibolites. Towards the south the metasediments are overthrust by the next migmatitic gneiss unit that belongs to a crustal scale nappe. The southwards dipping metasedimentary and volcanic sequence in the high Rwenzori mountains shows an inverse metamorphic grade with greenschist facies conditions in the north and amphibolite facies conditions in the south. Early D1 deformation structures are overgrown by cordierite, which in turn grows into D2 deformation, representing the major northwards directed thrusting event. We argue that the inverse metamorphic gradient develops because higher grade rocks are exhumed in the footwall of a crustal scale nappe whereas the exhumation decreases towards the north away from the nappe leading to a decrease in metamorphic grade. The D2 deformation event is followed by a D3 E-W compression, a D4 with the development of steep shear zones with a NNE-SSW and SSE-NNW trend including the large Nyamwamba shear followed by a local D5 retrograde event and D6 brittle inverse faulting. The Paleoproterozoic Buganda-Toro belt is relatively stiff and crosses the NNE-SSW running rift system exactly at the node where the highest peaks of the Rwenzori mountains are situated and where the lake George rift terminates towards the north. Orientation of brittle and ductile fabrics show some similarities indicating that the cross-cutting Buganda-Toro belt influenced rift propagation and brittle fault development within the Rwenzori mountain and that this stiff belt may form part of the reason why the Rwenzori mountains are relatively high within the rift. Keywords: East African Rift, Basement, Buganda Toro, Inverse Metamorphic Gradient, Microtectonics, Rwenzori mountain

True image

A still-life is often the painted record of a complex arrangement of objects. My aim in making the visual portion of TRUE IMAGE is to turn this sort of still-life inside out. Rather than arranging a collection of objects and making a painted or drawn image of the set up, I made simple images of things and arranged them with actual objects into three larger tableaux. The subjects of the paintings and drawings are these: checkerboards, objects, portraits, and shadows. The subjects of the tableaux are work (LABOR), home (DOMUS), and church (ECCLESIA). Viewed as a whole the exhibition asks questions about realism, artifice, illusion and perception