Retrograde Direction Research Articles

Intravascular Imaging for Chronic Total Occlusion Intervention

We sought to summarize the current evidence on use of intravascular imaging (with intravascular ultrasound [IVUS] or optical coherence tomography [OCT]) in chronic total occlusion (CTO) percutaneous coronary intervention (PCI). Utilization of intravascular imaging in CTO PCI is increasing over time, both to facilitate CTO crossing and for optimization of the final result. OCT is used less often than IVUS due to its lower depth of penetration and need for contrast injection. Intravascular imaging has multiple uses in CTO PCI: (a) it can facilitate CTO crossing by resolving proximal cap ambiguity and facilitating and confirming true lumen wire re-entry in case of initial subintimal wire crossing in both the antegrade and retrograde direction (for example by selecting the appropriate balloon size during the reverse controlled antegrade and retrograde tracking (reverse CART) technique; (b) it can be used to optimize the PCI result by ensuring good stent expansion and stent strut apposition, which may in turn result in lower rates of subsequent in-stent restenosis and stent thrombosis; (c) can facilitate evaluation and treatment of complications.

The climate of a retrograde rotating Earth

Abstract. To enhance understanding of Earth's climate, numerical experiments are performed contrasting a retrograde and prograde rotating Earth using the Max Planck Institute Earth system model. The experiments show that the sense of rotation has relatively little impact on the globally and zonally averaged energy budgets but leads to large shifts in continental climates, patterns of precipitation, and regions of deep water formation. Changes in the zonal asymmetries of the continental climates are expected given ideas developed more than a hundred years ago. Unexpected was, however, the switch in the character of the European–African climate with that of the Americas, with a drying of the former and a greening of the latter. Also unexpected was a shift in the storm track activity from the oceans to the land in the Northern Hemisphere. The different patterns of storms and changes in the direction of the trades influence fresh water transport, which may underpin the change of the role of the North Atlantic and the Pacific in terms of deep water formation, overturning and northward oceanic heat transport. These changes greatly influence northern hemispheric climate and atmospheric heat transport by eddies in ways that appear energetically consistent with a southward shift of the zonally and annually averaged tropical rain bands. Differences between the zonally averaged energy budget and the rain band shifts leave the door open, however, for an important role for stationary eddies in determining the position of tropical rains. Changes in ocean biogeochemistry largely follow shifts in ocean circulation, but the emergence of a “super” oxygen minimum zone in the Indian Ocean is not expected. The upwelling of phosphate-enriched and nitrate-depleted water provokes a dominance of cyanobacteria over bulk phytoplankton over vast areas – a phenomenon not observed in the prograde model. What would the climate of Earth look like if it would rotate in the reversed (retrograde) direction? Which of the characteristic climate patterns in the ocean, atmosphere, or land that are observed in a present-day climate are the result of the direction of Earth's rotation? Is, for example, the structure of the oceanic meridional overturning circulation (MOC) a consequence of the interplay of basin location and rotation direction? In experiments with the Max Planck Institute Earth system model (MPI-ESM), we investigate the effects of a retrograde rotation in all aspects of the climate system. The expected consequences of a retrograde rotation are reversals of the zonal wind and ocean circulation patterns. These changes are associated with major shifts in the temperature and precipitation patterns. For example, the temperature gradient between Europe and eastern Siberia is reversed, and the Sahara greens, while large parts of the Americas become deserts. Interestingly, the Intertropical Convergence Zone (ITCZ) shifts southward and the modeled double ITCZ in the Pacific changes to a single ITCZ, a result of zonal asymmetries in the structure of the tropical circulation. One of the most prominent non-trivial effects of a retrograde rotation is a collapse of the Atlantic MOC, while a strong overturning cell emerges in the Pacific. This clearly shows that the position of the MOC is not controlled by the sizes of the basins or by mountain chains splitting the continents in unequal runoff basins but by the location of the basins relative to the dominant wind directions. As a consequence of the changes in the ocean circulation, a “super” oxygen minimum zone develops in the Indian Ocean leading to upwelling of phosphate-enriched and nitrate-depleted water. These conditions provoke a dominance of cyanobacteria over bulk phytoplankton over vast areas, a phenomenon not observed in the prograde model.

Plate-assisted segmental bone transport with a lengthening nail and a plate : Anew technique for treatment of tibial and femoral bone defects

Distraction osteogenesis represents an effective procedure for treatment of bone defects from various causes (e.g. trauma, malignancy, congenital and infection). In the past the available procedures were practically exclusively external. In the plate-assisted segmental bone transport (PABST) procedure a commercially available motorized intramedullary lengthening nail is used for segment transport. The transport segment is transported along a bone plate, which is responsible for maintaining the position of the proximal and distal main fragments. In staged sequences, aplate spanning the defect is placed. A lengthening nail is inserted in an antegrade or retrograde direction and avascularized transport segment is created with an osteotomy. Bone transport is initiated at 1.0 mm a day. The transport segment is pulled or pushed into place, depending on the location of the bone void. In due time, a docking procedure is performed and full weight bearing is allowed. Supplementary lengthening can be initiated at docking or in a separate procedure.In smaller defects the gap is closed immediately over the plate and the bone is lengthened by the nail in the opposite end of the defect. The presented method is avaluable addition to the armamentarium for treatment of bone defects. The main advantages are the avoidance of external fixation (fixation wires, Schanz screws) and the creation of physiological bone substitute. Vital soft tissues are essential for agood outcome. With appropriate management (systematic debridement, local and systemic administration of antibiotics and free soft tissue flaps), this method can be asolution to even complex reconstructive problems.

Nonlinear thermal inertial waves in rotating fluid spheres

ABSTRACTWhen the Prandtl number is sufficiently small, the rotational constraint on convection in rotating systems is largely broken by inertial effects and the corresponding convective instability in leading order is described by non-dissipative thermal inertial waves propagating in either prograde or retrograde direction while buoyancy forces maintain the waves against viscous damping at next order. We investigate, via direct numerical simulation using a finite element method, the nonlinear properties of thermal inertial waves in rapidly rotating, self-gravitating, internally heated Boussinesq fluid spheres, concentrating on the liquid metal gallium with the Prandtl number . We analyze the nonlinear numerical solution by decomposing it into the spectrum of mathematically complete spherical inertial modes. Different forms of nonlinear convection, representing a sequence of bifurcations, are identified with increasing Rayleigh number. Near the threshold of convective instability, we show that the primary bifurcation is supercritical, dominated by a single thermal-inertial-wave mode, and consistent with the prediction of the existing asymptotic theory. At moderately supercritical Rayleigh numbers, we reveal that various thermal-inertial-wave modes with different radial/azimuthal/equatorial symmetries – which are convectively excited and maintained – become nonlinearly interactive, progressively breaking the temporal, radial, azimuthal and equatorial symmetries of the primary solution and, then, leading to a weakly turbulent state.

Intramedullary Fixation Techniques for the Anterior Pelvic Ring.

The superior ramus is an irregularly shaped, undulating, and curvilinear osseous structure that can provide an osseous conduit for intramedullary screws. A wide spectrum of variability between the curve and obliquity of the superior ramus osseous fixation pathway (OFP) exists in both the anteroposterior and the coronal planes. A detailed understanding of the osseous topography and how it correlates with fluoroscopic imaging is mandatory. Obtaining the correct intraoperative inlet and combined obturator oblique-outlet fluoroscopic views specific to each patient's anatomy is necessary for safe implant insertion. Intramedullary screws can be inserted in either an antegrade or a retrograde direction depending on a number of variables, including fracture location, the proximity of patient's external genitalia to the skin insertion side, and the possible impact of thigh girth on the surgeons hand position. Multiple screw insertion techniques are possible, but a simple and reproducible technique is described. The size and number of screws that can be inserted is variable, differs between surgeons, but is ultimately dependent on the cortical limits of the superior ramus OFP. Standard screw insertion techniques are successful in most patients. If the osseous corridor or external anatomy impedes standard insertional techniques, several modifications exist that can allow successful screw insertion. A thorough understanding of each patient's anatomy, injury, and precise surgical technique with the appropriate fluoroscopic views are required to safely place intraosseous intramedullary implants into the superior ramus OFP.

A contemporary view of atrioventricular nodal physiology.

In delaying transmission of the cardiac impulse from the atria to the ventricles, the atrioventricular (AV) node serves a critical function in augmenting ventricular filling during diastole and limiting the ventricular response during atrial tachyarrhythmias. The complex structure of the nodal region, however, also provides the substrate for reentrant rhythms. Recent discoveries have elucidated the cellular basis and anatomical determinants of slow conduction in the node. Based on analysis of gap junction proteins, distinct structural components of the AV node have been defined, including the compact node, right and left inferior nodal extensions, the lower nodal bundle, and transitional tissue. Emerging evidence supports the role of the inferior nodal extensions in mediating slow pathway conduction. The most common form of reentry involving the node, slow-fast AV nodal reentrant tachycardia (AVNRT), utilizes the inferior nodal extensions for anterograde slow pathway conduction; the structures responsible for retrograde fast pathway activation in the superior septum are less well defined and likely heterogeneous. Atypical forms of AVNRT arise from circuits that activate at least one of the inferior extensions in the retrograde direction.

Dual atrioventricular nodal pathways: physiology, arrhythmic findings, and electrocardiographic manifestations

The atrioventricular (AV) node is an anatomically well-defined structure, conveniently housed in the triangle of Koch. There are two distinct atrial impulse approaches to the AV node, one of which (in the anterior portion of triangle of Koch) has a faster conduction, while the other one (in the posterior portion) has a slower conduction. However, it is not said that such a conductive duality translates into any arrhythmic phenomena. Actually, these arrhythmias are due to an imbalance of the two pathways electrophysiological properties, which does not always exist. In the presence of such an imbalance, the dual AV nodal physiology is, however, the substrate for various arrhythmias and curious electrocardiographic behaviors. Often the fast pathway is characterized by a relatively long refractory period. In contrast, the slow approach is often characterized by shorter refractoriness.The unbalanced refractoriness of the two nodal pathways constitutes the prerequisite for the most common form of paroxysmal supraventricular tachycardia: the AV nodal reentrant tachycardia (AVNRT). In subjects prone to this type of arrhythmia, during sinus rhythm, nodal conduction usually occurs from the anterior approach (fast pathway). However, a premature atrial beat may find this pathway refractory and cross the AV node through the posterior approach (slow pathway), resulting in a sudden prolongation of the AV conduction time ("jump"). This allows the impulse, once it reaches the common end, to excitate the fast pathway in a retrograde direction and to return backwards to the atrium, thus triggering a circus movement that can result in a "slow-fast" AVNRT. More rarely, an AVNRT can take place in an opposite direction of the reentrant impulse ("fast-slow" variety of AVNRT). A paroxysmal supraventricular tachycardia may seldom occur with a regularly alternating RR cycle, if the reentrant mechanism involves retrogradely an accessory AV pathway and, in anterograde direction, a fast and a slow AV nodal pathway, alternately. Among the mechanisms underlying the total RR irregularity during atrial fibrillation, there is probably also the possibility that the AV node may offer to the atrial impulses two distinct pathways to reach the His bundle. Not too rarely, a dual AV nodal physiology can occur during sinus rhythm, through unexpected and sudden changes in the AV conduction time, so that two distinct PR families can be observed. It is likely that the presence of dual AV nodal pathways can facilitate or promote a Wenckebach conduction mechanism at nodal site.

The Longitudinal Evolution of Equatorial Coronal Holes

Abstract In 2011, three satellites—the Solar-Terrestrial RElations Observatory A & B, and the Solar Dynamics Observatory (SDO)—were in a unique spatial alignment that allowed a 360° view of the Sun. This alignment lasted until 2014, the peak of solar cycle 24. Using extreme ultraviolet images and Hovmöller diagrams, we studied the lifetimes and propagation characteristics of coronal holes (CHs) in longitude over several solar rotations. Our initial results show at least three distinct populations of “low-latitude” or “equatorial” CHs (below latitude). One population rotates in retrograde direction and coincides with a group of long-lived (over sixty days) CHs in each hemisphere. These are typically located between 30° and , and display velocities of ∼55 m s−1 slower than the local differential rotation rate. A second, smaller population of CHs rotate prograde, with velocities between ∼20 and 45 m s−1. This population is also long-lived, but observed ±10° from the solar equator. A third population of CHs are short-lived (less than two solar rotations), and they appear over a wide range of latitudes (±65°) and exhibit velocities between −140 and 80 m s−1. The CH “butterfly diagram” we developed shows a systematic evolution of the longer-lived holes; however, the sample is too short in time to draw conclusions about possible connections to dynamo-related phenomena. An extension of the present work to the 22 years of the combined SOHO–SDO archives is necessary to understand the contribution of CHs to the decadal-scale evolution of the Sun.

Flow past a near-wall retrograde rotating cylinder at varying rotation and gap ratios

The flow past a circular cylinder that is rotating retrograde near a turbulent wall boundary layer at Re = 10 000 has been investigated experimentally using particle image velocimetry (PIV). The cylinder rotates in retrograde direction with different rotation ratios from α = 0 to 2, where α is defined as the ratio of the peripheral speed on the cylinder surface divided by the free-stream velocity. The gap ratio, G* = G/D, is varied between 0 and 1.6, where G is the gap between the cylinder and the plane wall, and D is the cylinder diameter. The flow structure is greatly modified due to the influence of wall proximity and cylinder rotation, notably the onset/suppression, frequency and strength of vortex shedding. Similar to a near-wall stationary cylinder, there exists a critical gap ratio (about 0.4) below which periodic vortex shedding from the cylinder is suppressed. On the other hand, the cylinder rotation causes vortex shedding to cease at α ≥ 1.6, which is slightly lower than the reported value of α ≈ 2 in the literature on rotating cylinder in uniform flow. However, reducing G* and increasing α do not always favor the suppression of vortex shedding. In fact, cylinder rotation promotes vortex shedding over a certain range (α < 1). As α increases, the length of recirculation region behind the cylinder, which is indicated by the movement of the mean saddle point, decreases almost linearly. The effects of wall proximity and cylinder rotation are also evident on the ensemble-averaged flow field, such as the turbulent kinetic energy and Reynolds shear stress.

Structural and functional characterization of the contractile aorta and associated hemocytes of the mosquito Anopheles gambiae.

The primary pump of the circulatory system of insects is a dorsal vessel that traverses the length of the insect. The anterior portion, located in the head, neck and thorax, is the aorta, and the posterior portion, located in the abdomen, is the heart. Here, we characterize the structure and function of the aorta and conical chamber of the mosquito, Anopheles gambiae The aorta begins in the head with an excurrent opening located above the dorsal pharyngeal plate and ends at the thoraco-abdominal junction where it joins the conical chamber of the heart. The aorta lacks ostia, and based on the diameter of the vessel as well as the density and helical orientation of muscle, consists of three regions: the anterior aorta, the bulbous chamber, and the posterior aorta. The aorta contracts in the anterograde direction, but these contractions are independent of heart contractions and do not play a major role in hemolymph propulsion. Intravital imaging of the venous channels, the first abdominal segment and the neck revealed that hemolymph only travels through the aorta in the anterograde direction, and does so only during periods of anterograde heart flow. Furthermore, hemolymph only enters the thoraco-abdominal ostia of the conical chamber when the heart contracts in the retrograde direction, propelling this hemolymph to the posterior of the body. Finally, very few hemocytes associate with the aorta, and unlike what is seen in the periostial regions of the heart, infection does not induce the aggregation of hemocytes on the aorta.

Repatriarchalization of Young Mothers in Serbia Today — Presence of the Multiple Layers of Oppression that Create “Female Destiny”

<zaključak>The outcomes of the research do not indicate improvement of the equality of women in Serbian society today. In general, women's salaries are significantly lower than those of their partners, and the balance of life between private and public life is still undermined by the high burden on women with the responsibilities at home, in circumstances where family's budget depends on the paid work of both partners. Care for the elderly and sick stays exclusively female task. The outcomes of this research makes clear that the improvement of gender equality is not possible in conditions of a general decline in living standards. Several indicators point out that the values of women are marked by repatriarchalization. The retrograde direction becomes obvious when we compare three generations of respondents. The material standard of the youngest generation is the most uncertain, their average wage the lowest, the difference in income between them and their husbands/partners the biggest and therefore the dependence on the partner and the immediate social support is obvious. At the same time, the traditional division of gender roles, the burden of women with household tasks and care strongly persist among the youngest mothers. Concerning their attitudes and values, the generation of the youngest has values and attitudes that are more similar to the generation of the oldest generation, than to the middle aged respondents, who are the most emancipated.

Angular momentum transport by heat-driven g-modes in slowly pulsating B stars

Motivated by recent interest in the phenomenon of waves transport in massive stars, we examine whether the heat-driven gravity (g) modes excited in slowly-pulsating B (SPB) stars can significantly modify the stars' internal rotation. We develop a formalism for the differential torque exerted by g modes, and implement this formalism using the GYRE oscillation code and the MESASTAR stellar evolution code. Focusing first on a $4.21$ $M_\odot$ model, we simulate 1,000 years of stellar evolution under the combined effects of the torque due to a single unstable prograde g mode (with an amplitude chosen on the basis of observational constraints), and diffusive angular momentum transport due to convection, overshooting, and rotational instabilities. We find that the g mode rapidly extracts angular momentum from the surface layers, depositing it deeper in the stellar interior. The angular momentum transport is so efficient that by the end of the simulation the initially non-rotating surface layers are spun in the retrograde direction to $\approx30\%$ of the critical rate. However, the additional inclusion of magnetic stresses in our simulations, almost completely inhibits this spin-up. Expanding our simulations to cover the whole instability strip, we show that the same general behavior is seen in all SPB stars. After providing some caveats to contextualize our results, we hypothesize that the observed slower surface rotation of SPB stars (as compared to other B-type stars) may be the direct consequence of the angular momentum transport that our simulations demonstrate.

Ontogenesis of the pinealo-retinal neuronal connection in albino rats.

It was accepted for a long time that in mammals there is only retinofugal neuronal connection between the eye and the pineal body (PB). In our previous paper we described that nerve cells were present in hamster PB and these neurons could establish a reverse connection with the retina through a transsynaptic pathway. In adult albino rats neuronal perikarya were not found. In this present experiment it was examined whether the lack of these nerve cells in the PB of adult rats is the result of an apoptotic phenomenon or the lack of migration during the fetal period. Green fluorescence protein expressing pseudorabies virus, spreading only in retrograde direction, was injected into the vitreous body of rats at various postnatal ages. Virus labeled cell bodies were not observed in the PB of adult rats; however, labeling with gradually decreasing number of cells was present in animals aged 3-6, 13-14, 20, 35 and 41 postnatal days. Injection of virus, spreading in anterograde direction (expressing red fluorescence protein), into the PB of young prepubertal animals resulted in labeling in the retina. This observation indicates that the pinealo-retinal connection in prepubertal period is active. Immunostaining revealed that some of the labeled neuronal perikarya showed activated caspase-3 (an apoptotic marker) immunoreactivity. Our results clearly show that the neurons migrate to the PB and later, during the prepubertal period, they disappear. Caspase-3 immnoreactivity indicates that these cells die off by apoptosis.

Axonemal Lumen Dominates Cytosolic Protein Diffusion inside the Primary Cilium

Transport of membrane and cytosolic proteins in primary cilia is thought to depend on intraflagellar transport (IFT) and diffusion. However, the relative contribution and spatial routes of each transport mechanism are largely unknown. Although challenging to decipher, the details of these routes are essential for our understanding of protein transport in primary cilia, a critically affected process in many genetic diseases. By using a high-speed virtual 3D super-resolution microscopy, we have mapped the 3D spatial locations of transport routes for various cytosolic proteins in the 250-nm-wide shaft of live primary cilia with a spatiotemporal resolution of 2 ms and <16 nm. Our data reveal two spatially distinguishable transport routes for cytosolic proteins: an IFT-dependent path along the axoneme, and a passive-diffusion route in the axonemal lumen that escaped previous studies. While all cytosolic proteins tested primarily utilize the IFT path in the anterograde direction, differences are observed in the retrograde direction where IFT20 only utilizes IFT, and approximately half of KIF17 and one third of α–tubulin utilizes diffusion besides IFT.

EP04.40: Case report of Ebstein's anomaly which dynamic slow‐motion display was useful for a diagnosis of the functional pulmonary atresia

A 23-year-old woman was referred for fetal echocardiography at 19 weeks' gestation because of suspected cardiomegaly. Fetal echocardiography demonstrated a cardiomegaly (cardiothoracic area ratio was 45%) and severe tricuspid valve insufficiency in the 4 chambers. We diagnosed Ebstein's anomaly. The pulmonary artery flow was observed in an anterograde direction. At 32 weeks' gestation, fetal echocardiography showed severe cardiomegaly (cardiothoracic area ratio was 55%) and the pulmonary artery flow was observed in a retrograde direction. On more careful investigation of using the dynamic slow-motion display, a little regurgitation flow to a pulmonary valve in end systole could be visualised. Therefore, we diagnosed functional pulmonary atresia. Because the dynamic slow-motion display can depict an image by slow motion without deteriorating, it is useful for a diagnosis of the functional pulmonary atresia.

Axonal spheroids in ovine neuroaxonal dystrophy are immunopositive to kinesin and dynein.

Neuroaxonal dystrophy (NAD) is a neurologic disorder of sheep characterized by accumulation of numerous axonal swellings (spheroids) in specific regions of the brainstem and spinal cord. Disruption of axonal transport, which is driven in anterograde and retrograde directions by the molecular motors, kinesin and dynein, respectively, is believed to contribute to spheroid development. Accordingly, we examined spheroids in ovine NAD cases immunohistochemically for kinesin and dynein and found both motor proteins, with dynein more strongly expressed than kinesin. Further investigations of the kinesin and dynein content of axonal spheroids in NAD, and other neurodegenerative disorders of domestic animals, could assist in better understanding the pathogenesis of these diseases.

Increased transgene expression level of rabies virus vector for transsynaptic tracing.

Viral vectors that can infect neurons transsynaptically and can strongly express foreign genes are useful for investigating the organization of neural circuits. We previously developed a propagation-competent rabies virus (RV) vector based on a highly attenuated HEP-Flury strain (rHEP5.0-CVSG), which selectively infects neurons and propagates between synaptically connected neurons in a retrograde direction. Its relatively low level of transgene expression, however, makes immunostaining necessary to visualize the morphological features of infected neurons. To increase the transgene expression level of this RV vector, in this study we focused on two viral proteins: the large protein (L) and matrix protein (M). We first attempted to enhance the expression of L, which is a viral RNA polymerase, by deleting the extra transcription unit and shortening the intergenic region between the G and L genes. This viral vector (rHEP5.0-GctL) showed increased transgene expression level with efficient transsynaptic transport. We next constructed an RV vector with a rearranged gene order (rHEP5.0-GML) with the aim to suppress the expression of M, which plays a regulatory role in virus RNA synthesis. Although this vector showed high transgene expression level, the efficiency of transsynaptic transport was low. To further evaluate the usability of rHEP5.0-GctL as a transsynaptic tracer, we inserted a fluorescent timer as a transgene, which changes the color of its fluorescence from blue to red over time. This viral vector enabled us the differentiation of primary infected neurons from secondary infected neurons in terms of the fluorescence wavelength. We expect this propagation-competent RV vector to be useful for elucidating the complex organization of the central nervous system.

The Retrograde-Antegrade-Retrograde Technique for Successful Placement of a Retrograde Superior Ramus Screw.

Stabilization of pelvic ring injuries and certain acetabular fractures using percutaneous techniques is becoming increasingly more common. Intramedullary superior ramus screw fixation is beneficial in both injury types. While implants can be placed in an antegrade or retrograde direction, parasymphyseal ramus fractures benefit from retrograde implant insertion. In some patients, the parabolic osseous anatomy or obstructing soft tissues of the anterior pelvis or thigh can prevent appropriate hand and instrumentation positioning for appropriate retrograde ramus screw insertion through the entire osseous fixation pathway. Instead of abandoning medullary fixation, we propose a technique utilizing cannulated screws to successfully place retrograde screws in this distinct clinical scenario.

The "rectosigmoid brake": Review of an emerging neuromodulation target for colorectal functional disorders.

The regulation of gastrointestinal motility encompasses several overlapping mechanisms including highly regulated and coordinated neurohormonal circuits. Various feedback mechanisms or "brakes" have been proposed. While duodenal, jejunal, and ileal brakes are well described, a putative distal colonic brake is less well defined. Despite the high prevalence of colonic motility disorders, there is little knowledge of colonic motility owing to difficulties with organ access and technical difficulties in recording detailed motor patterns along its entire length. The motility of the colon is not under voluntary control. A wide range of motor patterns is seen, with long intervals of intestinal quiescence between them. In addition, the use of traditional manometric catheters to record contractile activity of the colon has been limited by the low number of widely spaced sensors, which has resulted in the misinterpretation of colonic motor patterns. The recent advent of high-resolution (HR) manometry is revolutionising the understanding of gastrointestinal motor patterns. It has now been observed that the most common motor patterns in the colon are repetitive two to six cycles per minute (cpm) propagating events in the distal colon. These motor patterns are prominent soon after a meal, originate most frequently in the rectosigmoid region, and travel in the retrograde direction. The distal prominence and the origin of these motor patterns raise the possibility of them serving as a braking mechanism, or the "rectosigmoid brake," to limit rectal filling. This review aims to describe what is known about the "rectosigmoid brake," including its physiological and clinical significance and potential therapeutic applications.

A Comparison of Two Commonly Used Methods for Securing Intravenous Cannulas.

There is a wide variety of techniques to secure intravenous cannulas but little objective evidence to support their relative efficacy. This study compares the security of the two most common methods used within a major Australian Emergency Department. The plastic sheaths of four needle-less intravenous cannulas were secured to the skin surface (not intravenously) of 40 volunteers using two different taping styles, an "under and over" method with one of the tapes applied to the posterior surface of the hub then crossed anteriorly to adhere to the opposite skin surface or "horizontal" taping with the tapes applied horizontally across the anterior surface of the hub. The peak force required to dislodge the taped cannulas using each of these different methods was then measured in both an anterograde and retrograde direction of force using a force transducer. The force required to dislodge a cannula taped in an 'under and over' taping style was significantly higher than that required for the horizontal taping in both anterograde and retrograde directions of force (p < 0.001). The results of this study suggest that the "under and over" taping technique offers significantly more security than "horizontal" taping and should be considered as a more effective method for securing intravenous cannulas.