Distal Bodies Research Articles

Evaluation of the accuracy of conventional and digital implant impression techniques in bilateral distal extension cases: a randomized clinical trial

BackgroundThis clinical study aims to evaluate the accuracy of the conventional implant impression techniques compared to the digital impression ones in bilateral distal extension cases.MethodsA total of 32 implants were placed in eight patients missing all mandibular posterior teeth except the first premolars. Each patient received a total of four implants, with two implants placed on each side, in order to provide support for three units of screw-retained zirconia restorations. Following osteointegration, the same patient underwent two implant-level impression techniques: Conventional open-tray impressions CII (splinted pick-up) and digital implant impressions DII with TRIOS 3 Shape intraoral scanner. The accuracy of impressions was evaluated utilizing a three-dimensional superimposition analysis of standard tessellation language (STL) files. Subsequently, the scan bodies were segmented using Gom inspect software to measure three-dimensional deviations in a color-coding map. Data were statistically analyzed using the Kruskal Wallis test and then a post-hoc test to determine the significance level (P < 0.05).ResultsThe study revealed that higher angular and positional deviations were shown toward distal scan bodies compared to mesial ones for both impression techniques. However, this difference was not statistically significant (P > 0.05).ConclusionSplinted open-tray conventional impression and intraoral scanning implant impression techniques have demonstrated comparable accuracy.Trial registrationClinical Trials.gov Registration ID NCT05912725. Registered 22/06/ 2023- Retrospectively registered, https://register.clinicaltrials.gov.

Cook Zenith Alpha Endograft: A Protocol to Minimise Limb Graft Occlusion

Numerous articles have reported an increased incidence of limb graft occlusion (LGO) with the Cook Zenith Alpha endograft compared with other endografts in endovascular aortic aneurysm repair (EVAR). The present study aimed to assess the rate of LGO after EVAR in particular with the Cook Zenith Alpha device when adhering to a standardised protocol designed to prevent limb related complications. This was a non-sponsored retrospective study performed in two university vascular surgery centres employing the same protocol for limb complication prevention during EVAR from 2016 to 2019. The protocol encompassed: (1) angioplasty of any common or external iliac artery with > 50% stenosis before endograft navigation; (2) proximal sealing zone of limbs at the same level of the flow divider with minimum overlap, which is more restrictive than the Cook Zenith Alpha instructions for use; (3) semi-compliant kissing ballooning of limbs; (4) limb stenting for any residual tortuosity, kinking, or stenosis; and (5) adjunctive common and external iliac stenting for residual stenosis or dissection after EVAR. Patients enrolled in this study were treated with standard aortobi-iliac EVAR. Follow up was performed by clinical visit and duplex ultrasonography at discharge, six months, and yearly thereafter. The primary endpoint was to evaluate the LGO rate with different EVAR devices (Cook Zenith Alpha, Gore C3, and Medtronic Endurant) and to determine potential risk factors for LGO associated with the Zenith Alpha. In the study period, 547 EVARs were considered: 233 (42.6%) Cook Zenith Alpha, 196 (35.8%) Gore Excluder,and 118 (21.6%) Medtronic Endurant. The mean follow up was 44 ± 23 months, and the five year freedom from LGO was 97 ± 3%, without differences between groups (97 ± 2%, 95 ± 3%, and 100% with Cook Zenith Alpha, Medtronic Endurant, and Gore Excluder, respectively; p= .080). In the Zenith Alpha group, intra-operative adjunctive iliac artery angioplasty, iliac artery stenting, or iliac limb stenting was performed in 8%, 3.4%, and 9.7% of cases, respectively. Analysis of potential risk factors for LGO identified external iliac artery distal landing and large main bodies (ZIMB 32 - 36) to be independently associated with LGO during follow up (hazard ratio [HR] 18, 95% confidence interval [CI] 3 - 130, p= .004; and HR 12, 95% CI 1.2 - 130, p= .030, respectively). The present experience with a protocol for limb complication prevention allows achievement of a low rate of LGO at five years with Zenith Alpha endografts similar to other endografts. Specific risk factors for the Cook Zenith Alpha endograft are external iliac artery distal landing and the use of a large main body (ZIMB 32 - 36).

The differences in the anatomy of the thoracolumbar and sacral autonomic outflow are quantitative.

We have re-evaluated the anatomical arguments that underlie the division of the spinal visceral outflow into sympathetic and parasympathetic divisions. Using a systematic literature search, we mapped the location of catecholaminergic neurons throughout the mammalian peripheral nervous system. Subsequently, a narrative method was employed to characterize segment-dependent differences in the location of preganglionic cell bodies and the composition of white and gray rami communicantes. One hundred seventy studies were included in the systematicreview, providinginformation on 389 anatomical structures. Catecholaminergic nerve fibers are present in most spinal and all cranial nerves and ganglia, including those that are known for their parasympathetic function. Along the entire spinal autonomic outflow pathways, proximal and distal catecholaminergic cell bodies are common in the head, thoracic, and abdominal and pelvic region, which invalidates the "short-versus-long preganglionic neuron" argument. Contrary to the classically confined outflow levels T1-L2 and S2-S4, preganglionic neurons have been found in the resulting lumbar gap. Preganglionic cell bodies that are located in the intermediolateral zone of the thoracolumbar spinal cord gradually nest more ventrally within the ventral motor nuclei at the lumbar and sacral levels, and their fibers bypass the white ramus communicans and sympathetic trunk to emerge directly from the spinal roots. Bypassing the sympathetic trunk, therefore, is not exclusive for the sacral outflow. We conclude that the autonomic outflow displays a conserved architecture along the entire spinal axis, and that the perceived differences in the anatomy of the autonomic thoracolumbar and sacral outflow are quantitative.

Ossification pursue of the lower ends of radius and ulna and age determination in a sample of Egyptian population between 12 and 19 years

The epiphyseal plates of cartilage of ulna and radius is responsible for bone elongation, the fusion of their distal ends and bodies is used for age estimation. Variation exists due to many factors including ethnicity; accordingly, it is important to create a national profile for age determination using an affordable easy method. The aim of the work was to follow up the ossification of the lower end of the radius and the ulna in the Egyptian population between 12-19 years using X-ray, validating the use of Greulich and Pyle atlas. 197 subjects (103 males and 94 females) aged between 12-19 years were included. Skeletal age was determined using a plain X-ray on the lower end of the radius and the ulna comparing it to Greulich and Pyle’s atlas, and also to chronological age. In males, the mean of chronological age, skeletal age, and the difference between them were 15.35, 15.53 and +0.18 years respectively. In females, the ages were 14.77, 14.92 and +0.15. There was high correlation in all age groups. Examination of the lower end of the radius and the ulna is a suitable method for age detection in Egyptians between the ages of 12-19 years old.

Metasomatism and cyclic skarn growth along lithological contacts: Physical and geochemical evidence from a distal Pb[sbnd]Zn skarn

Distal skarns form by the metasomatic reactions of a host rock induced by far-traveled hydrothermal fluids. Physical and structural characteristics and geochemical patterns of distal PbZn skarn bodies were studied at the Petrovitsa deposit in southern Bulgaria. Skarn bodies formed from the interaction of hydrothermal fluids with reactive host lithologies (marble and gneiss). These fluids were transported along sub-vertical feeder structures and lithological contacts. Epidote skarn developed in gneiss protolith, and pyroxene (johannsenite) skarn developed in marble. Detailed geological mapping, complimented by measurements of the internal structure of the skarn body using pyroxene growth versors, quantifies the propagation direction of the skarn body: 1) away from the major local fluid conduit (feeder structure), and 2) away from lithological contacts between aluminosilicate rock and marble. Such growth suggests that fluid flow was generally orthogonal to the skarn front propagation direction in the pyroxene skarn.Textural, mineralogical and geochemical data from skarn samples reveal multiple growth generations of major skarn calc-silicates epidote and pyroxene. The epidote skarn is characterized by limited spatial distribution and fine-grained epidote/clinozoisite growth associated with massive replacement and sulfide mineralization. The pyroxene skarn consists of acicular clinopyroxene crystals which form spheroidal aggregates with discrete growth banding. These bands are the physical representation of the cyclic fluid pulses which resulted in rhythmic skarn growth marked by geochemical banding. In situ geochemical analyses in the epidote skarn reveal early Al-rich epidote overprinted by Fe-rich epidote associated with higher Mn and Sr contents and irregular compositional banding. Clinopyroxene (Jo60–95) shows general increase in Na, Al, Mn, and REE + Y with distance from the feeder structure and lithologic contacts. These elements correlate with the distance traveled by the hydrothermal fluid from the feeder to the site of skarnification, which we define using a proxy based on the Al content of pyroxene crystals. This reflects an increasing degree of fluid “contamination” by interaction with the aluminosilicate host rocks and functions as a proxy for fluid transport distance. The spatial distribution of trace-elements in pyroxene on an outcrop scale is indicative of discrete pulses of hydrothermal fluid resulting in precipitation of skarn calc-silicates along the increasingly tortuous fluid pathway between the feeder structure and the skarn front, resulting in both the macro- and micro-scale chemical and textural variability of the skarn body.

Transdiaphragmatic Gastrotomy for the Extraction of Distal Esophageal Foreign Bodies in 13 Dogs (1997-2016).

The records of 13 dogs with distal esophageal foreign body obstruction not amenable to endoscopic management that had transdiaphragmatic gastrotomy (TG) for the foreign body extraction were reviewed. West Highland white terriers were over-represented. Mean age of the dogs at presentation was 38.6 mo, and mean duration of clinical signs associated with esophageal foreign bodies was 5.8 days. A TG was performed via an eighth or ninth left intercostal thoracotomy, and clinical results were successful in 12 dogs. In 1 dog, gastrotomy failed to retrieve a foreign body and esophagotomy was performed. Foreign bodies that were removed included 3 fishhooks and 10 animal bones. Postoperatively, all dogs developed esophagitis, 1 dog showed esophageal stricture, and 1 dog died of pyothorax associated with esophageal perforation 1 day postsurgery. Overall, 12 dogs survived and were free of clinical signs after a median follow-up time of 17 mo. TG is an effective surgical technique for the retrieval of distal esophageal foreign bodies.

Abstract 3380: Methylome analysis of non-alcoholic fatty liver disease-associated hepatocellular carcinoma reveals etiology-specic pathway perturbations

Abstract Chronic hepatitis B infection (HBV) and non-alcoholic fatty liver disease (NAFLD) have been shown to induce aberrant DNA methylation that may contribute to the development of hepatocellular carcinoma (HCC), which is one of the most common liver cancers. Most previous studies on DNA methylation in HCC have focused on altered methylation at gene promoters and CpG islands/shores. However, it has been increasingly recognized that DNA methylation in other genomic regions, including distal enhancers and gene bodies, could also play important roles in gene regulation in cancers. In our whole-genome bisulfite sequencing (WGBS) analysis of 10 human HBV-associated tumors and 10 human NAFLD-associated tumors, methylation states at all CpG sites in the genome of HCC tumors are comprehensively studied. To see how the methylomes of these two groups of HCC samples are related to other liver-related normal and pathogenic samples, we collected published WGBS data for HCC tumor, tumor adjacent and normal liver samples. Global hypermethylation of NAFLD-HCC has been identified compared with HBV-HCC and differentially methylated regions in enhancer and gene body regions also have been detected. Different methylation patterns for HCC pathogenesis with different etiologies have been detected and may offer potentially more specific therapeutic targets. This project is supported by Collaborative Research Fund C4017-14G and the Focused Innovations Scheme 1907309. Citation Format: Qiong Wu. Methylome analysis of non-alcoholic fatty liver disease-associated hepatocellular carcinoma reveals etiology-specic pathway perturbations [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 3380.

Evidence for a 200 km thick diamond-bearing root beneath the Central Mackenzie Valley, Northwest Territories, Canada? Diamond indicator mineral geochemistry from the Horn Plateau and Trout Lake regions

The Central Mackenzie Valley (CMV) area of Northwest Territories is underlain by Precambrian basement belonging to the North American Craton. The potential of this area to host kimberlitic diamond deposits is relatively high judging from the seismologically-defined lithospheric thickness, age of basement rocks (2.2–1.7 Ga) and presence of kimberlite indicator minerals (KIMs) in Quaternary sediments. This study presents data for a large collection of KIMs recovered from stream sediments and till samples from two study areas in the CMV, the Horn Plateau and Trout Lake. In the processed samples, peridotitic garnets dominate the KIM grain count for both regions (> 25% each) while eclogitic garnet is almost absent in both regions (< 1% each). KIM chemistry for the Horn Plateau indicates significant diamond potential, with a strong similarity to KIM systematics from the Central and Western Slave Craton. The most significant issue to resolve in assessing the local diamond potential is the degree to which KIM chemistry reflects local and/or distal kimberlite bodies. Radiogenic isotope analysis of detrital kimberlite-related CMV ilmenite and rutile grains requires at least two broad age groups for eroded source kimberlites. Statistical analysis of the data suggests that it is probable that some of these KIMs were derived from primary and/or secondary sources within the CMV area, while others may have been transported to the area from the east-northeast by Pleistocene glacial and/or glaciofluvial systems. At this stage, KIM chemistry does not allow the exact location of the kimberlitic source(s) to be constrained.

Potassium-regulated distal tubule WNK bodies are kidney-specific WNK1 dependent.

With-no-lysine (WNK) kinases coordinate volume and potassium homeostasis by regulating renal tubular electrolyte transport. In the distal convoluted tubule (DCT), potassium imbalance causes WNK signaling complexes to concentrate into large discrete foci, which we call "WNK bodies." Although these structures have been reported previously, the mechanisms that drive their assembly remain obscure. Here, we show that kidney-specific WNK1 (KS-WNK1), a truncated kinase-defective WNK1 isoform that is highly expressed in the DCT, is critical for WNK body formation. While morphologically distinct WNK bodies were evident in the distal tubules of mice subjected to dietary potassium loading and restriction, KS-WNK1 knockout mice were deficient in these structures under identical conditions. Combining in vivo observations in kidney with reconstitution studies in cell culture, we found that WNK bodies are dynamic membraneless foci that are distinct from conventional organelles, colocalize with the ribosomal protein L22, and cluster the WNK signaling pathway. The formation of WNK bodies requires an evolutionarily conserved cysteine-rich hydrophobic motif harbored within a unique N-terminal exon of KS-WNK1. We propose that WNK bodies are not pathological aggregates, but rather are KS-WNK1-dependent microdomains of the DCT cytosol that modulate WNK signaling during physiological shifts in potassium balance.

Abstract: Clitoroplasty and Labia Minoraplasty in Penile Inversion Vaginoplasty in Circumcised and Uncircumcised Transwomen

INTRODUCTION: Gender dysphoria, the incongruence between anatomic sex and gender identity is estimated to affect 1% of the population. Creation of a feminine vulva remains a technical challenge for surgeons, especially in circumcised patients. We present a vulvoplasty technique with creation of neoclitoris and labia minora using a dorsal glans pedicled flap with prepuce skin in uncircumcised patients or distal shaft skin in circumcised patients. METHODS: A retrospective case review was performed of all penile inversion vaginoplasties performed by senior author between 2014 and 2016. History of circumcision, use of full thickness skin grafts to lengthen vault, necrosis of labia minora, and any revisionary surgery was recorded. RESULTS: A total of 159 single stage penile inversion vaginoplasty operations were performed using the described technique from 2014–2016. All patients were evaluated by the UZ Gent multidisciplinary gender team prior to surgery and met standards of care established by WPATH. The majority, 97.5 % of patients, required FTSG to lengthen the vaginal vault. Creation of clitoral hood and labia minora was achieved in all patients with 3.2 % requiring minor aesthetic refinements for partial skin necrosis and 25.8% for labia majora refienments or dehiscence. Just one patient experienced total necrosis of the labia minora prepuce flap tissue. Average length of follow-up was 2 years. The neoclitoris is constructed from a M-shape dorsal glans flap, sutured into a dome, and inset to the distal resected corporal bodies in the anterior midline. The urethra mucosa is inset as a shield and the prepuce flap is wrapped laterally and posteriorly to construct labia minora. In circumcised patients, distal penile shaft skin is used in absence of prepuce skin and survives on random blood supply through the circumcision scar. Labia majora are fashioned from the scrotal skin. Remaining penile shaft skin is inverted to construct the introitus and vaginal apex is lined with full thickness skin graft from excess scrotal skin. Postoperative genital aesthetics were excellent. CONCLUSION: Creation of the clitoral hood and labia minora during penile inversion vaginoplasty is achievable in both circumcised and uncircumcised patients with excellent aesthetic results and low revisionary surgery rate.

The incidence of isolated penile torsion in North India: A study of 5,018 male neonates

Congenital penile torsion is a three-dimensional deformity with helical rotation of the distal corporal bodies with the penile crurae remaining fixed to the pubic rami. The first case of congenital penile torsion (hypospadias) was described in 1857. Isolated penile torsion is an under-reported anomaly. The reported incidence of isolated penile torsion is 1.7-27% and severe torsion is 0.7%. There are no studies available from Indian subcontinent on the incidence of isolated penile torque. The objective of this study was to determine the overall incidence of isolated penile torque in a north Indian population. A prospective study of deliveries of male children was conducted at our institute between April 2014 and June 2015. Penile torsion was measured using a small protractor either by the deviation of the median raphae or the direction of the meatus. Data were collected on the incidence of congenital isolated penile torsion, including the degree and direction (left or right) of torsion. Torsion was classified as mild (<450), moderate (450-900), and severe (>900). Statistical analysis was done using the chi-square test with variables of age and parity of the mother and weight of the child. There were 99 cases of isolated penile torque among 5018 male neonates assessed for penile torque. The incidence of isolated penile torque was 19.7 per 1000 births. The degree of torsion varied from 30 to 110° (average 51.46°). Seventy-nine percent (79%) of them had left side and 21% had right side torque (4:1). The degree of torsion was mild in 30%, with 20% having left side torque and 10% having right side torque (2:1). A moderate degree of torsion was seen in 69%: 84% of them had left torque and only 16% had right sided torque (5:1). Only one patient had severe left torque. The incidence of isolated congenital penile torsion was highest in the maternal age group of >30 years followed by the 26-30-year age group, and was lowest in 21-25 year age group. In multiparous women, the incidence of isolated congenital penile torsion was highest (2.54%), and it was lowest in primiparous women (1.36%). The incidence of isolated penile torsion was 1.97% and the left-to-right ratio was 3:1, but for moderate torque it was 5:1. There was a strong association between incidence of penile torque with the age of the mother (p=0.012) and parity (p=0.008) but not with the weight of the baby (p=0.415).

Touch at a distance: toward a phenomenology of film

“We cannot open our eyes to things without distancing ourselves from what we seek. Separation is the price of vision” (de Certeau in Enclitic 7: 24–31, 1983). Yet, what happens when what we see at a distance grabs us, touches us, drawing us closer (Blanchot 1981)? Is this not the experience of film? In this article I argue that modulating distance lies at the heart of perception and filmmaking, palpable tensions in moving closer-to (proximal) and distancing-from (distal) bodies and things, entangling senses across the sensorium in what is called haptic perception and, by extension, haptic cinema. I explore modulation in distancing in revisiting Vittorio De Sica’s Italian neorealist film, Umberto D., a film customarily discussed in optical-ocular terms. En route we experience De Sica’s artistry in conveying ‘instants in life’ and ‘spectral distancing’ and we have a visitation with Agamben’s (2000) gestural cinema which exposes the mediality of film, opening up haptic-ethical thought and expression. In the final section I push toward a phenomenology of film inspired by Merleau-Ponty’s (1968) reversibility in perception and Morris’s (2002) associated ideas of tactile resonance and reverberation. I articulate a phenomenology of filmic-body couplings as lived moments in touch that resonate, reverberate and linger as affective intensities, taking cinema beyond the theater, screen, spectator, image, and representational logics.

Tomographic anatomy of the vena cava and renal veins: features relevant to vena cava filter placement

BACKGROUND: There is a growing demand for invasive procedures involving the inferior vena cava, in particular for placement of vena cava filters. It is not always easy to identify the more distal renal vein with cavography, for safe release of filters. OBJECTIVES: To determine parameters for the relationships between the renal veins and the infrarenal vena cava and their corresponding vertebral bodies, their relationships with biotype and the occurrence of anatomic variations, the relationships between vertebral bodies and the bifurcation of the common iliac veins and the distance from this bifurcation to the outflow of the more distal renal vein, with reference to placement of vena cava filters. METHODS: A total of 150 abdominal computed tomography scans conducted from October to November 2011 were analyzed and classified according to the biotype exhibited (using Charpy's angle). Scans were performed at MEDIMAGEM and analyzed at the Integrated Vascular Surgery Service, both part of Hospital da Beneficência Portuguesa in São Paulo, Brazil. RESULTS: In 127 of the 150 scans analyzed (84.66%), the more distal renal vein emerged between the first lumbar intervertebral space (L1-L2) and the body of L2, irrespective of patient biotype. Just 23 patients (15.33%) exhibited a more distal renal vein with outflow below the body of L2, i.e. in the projection of the space between L2 and L3. CONCLUSIONS: The radiological correlation between the confluence of the more distal renal vein and vertebral bodies exhibits little variation, irrespective of the biotype of the patient.

Long-term depression is differentially expressed in distinct lamina of hippocampal CA1 dendrites.

Information storage in CA1 hippocampal pyramidal neurons is compartmentalized in proximal vs. distal apical dendrites, cell bodies, and basal dendrites. This compartmentalization is thought to be essential for synaptic integration. Differences in the expression of long-term potentiation (LTP) in each of these compartments have been described, but less is known regarding potential differences in long-term depression (LTD). Here, to directly compare LTD expression in each compartment and to bypass possible differences in input-specificity and stimulation of presynaptic inputs, we used global application of NMDA to induce LTD. We then examined LTD expression in each dendritic sub-region—proximal and distal apical, and basal dendrites—and in cell bodies. Interestingly, we found that distal apical dendrites exhibited the greatest magnitude of LTD of all areas tested and this LTD was maintained, whereas LTD in proximal apical dendrites was not maintained. In basal dendrites, LTD was also maintained, but the magnitude of LTD was less than in distal apical dendrites. Blockade of inhibition blocked LTD maintenance in both distal apical and basal dendrites. Population spikes recorded from the cell body layer correlated with apical dendrite field EPSP (fEPSP), where LTD was maintained in distal dendrites and decayed in proximal dendrites. On the other hand, LTD of basal dendrite fEPSPs was maintained but population spike responses were not. Thus E-S coupling was distinct in basal and apical dendrites. Our data demonstrate cell autonomous differential information processing in somas and dendritic sub-regions of CA1 pyramidal neurons in the hippocampus, where LTD expression is intrinsic to distinct dendritic regions, and does not depend on the nature of stimulation and input specificity.

Computational fluid dynamic analysis of the effect of morphologic features on distraction forces in fenestrated stent grafts

Secure fixation of endovascular stent grafts is essential for successful endovascular aneurysm repair. Hemodynamic distraction forces are generated by blood pressure and blood flow and act against fixation force to encourage migration that may eventually lead to late stent graft failure. The aim of this in silico study was to determine which morphologic features were associated with greater distraction force. Computer models of 54 in situ fenestrated stent grafts were constructed from postoperative computed tomography scans by use of image processing software. Computational fluid dynamic analysis was then performed by use of a commercial finite volume solver with boundary conditions representative of peak systole. Distraction force results were obtained for each component of the stent graft. Distraction force was correlated with lumen cross-sectional area (XSA) at the inlet and outlet of components and was compared between groups of components, depending on the magnitude of four predefined angles within the aortoiliac territory that we describe in detail. Median total resultant distraction force (RDF) acting on the fenestrated proximal bodies was 4.8 N (1.3-15.7 N); bifurcated distal bodies, 5.6N (1.0-8.0 N); and limb extensions, 1.7 N (0.6-8.4N). Inlet XSA exhibited strong, positive correlation with total RDF in proximal body and distal body components (Spearman correlation coefficient ρ, 0.883 and 0.802, respectively). Outlet XSA exhibited a similarly strong, positive correlation with total RDF in limb extension components (ρ, 0.822). Outlet angulation ≥ 45 degrees was associated with greater total RDF in the limb extension components only (P = .004). For a given blood pressure, XSA was the most important morphologic determinant of total RDF. Angulation within the aorta was not large enough to influence this, whereas iliac angulation affecting outlet angulation of limb extension components was associated with significantly greater total RDF.

Dune bedforms produced by dilute pyroclastic density currents from the August 2006 eruption of Tungurahua volcano, Ecuador

A series of pyroclastic density currents were generated at Tungurahua volcano (Ecuador) during a period of heightened activity in August 2006. Dense pyroclastic flows were confined to valleys of the drainage network, while dilute pyroclastic density currents overflowed on interfluves where they deposited isolated bodies comprising dune bedforms of cross-stratified ash exposed on the surface. Here, the description, measurement, and classification of more than 300 dune bedforms are presented. Four types of dune bedforms are identified with respect to their shape, internal structure, and geometry (length, width, thickness, stoss and lee face angles, and stoss face length). (1) “Elongate dune bedforms” have smooth shapes and are longer (in the flow direction) than wide or thick. Internal stratification consists of stoss-constructional, thick lensoidal layers of massive and coarse-grained material, alternating with bedsets of fine laminae that deposit continuously on both stoss and lee sides forming aggrading structures with upstream migration of the crests. (2) “Transverse dune bedforms” show linear crests perpendicular to the flow direction, with equivalent lengths and widths. Internally, these bedforms exhibit finely stratified bedsets of aggrading ash laminae with upstream crest migration. Steep truncations of the bedsets are visible on the stoss side only. (3) “Lunate dune bedforms” display a barchanoidal shape and have stratification patterns similar to those of the transverse ones. Finally, (4) “two-dimensional dune bedforms” are much wider than long, exhibit linear crests and are organized into trains. Elongate dune bedforms are found exclusively in proximal deposition zones. Transverse, lunate, and two-dimensional dune bedforms are found in distal ash bodies. The type of dune bedform developed varies spatially within an ash body, transverse dune bedforms occurring primarily at the onset of deposition zones, transitioning to lunate dune bedforms in intermediate zones, and two-dimensional dune bedforms exclusively on the lateral and distal edges of the deposits. The latter are also found where flows moved upslope. Elongate dune bedforms were deposited from flows with both granular-based and tractional flow boundaries that possessed high capacity and competence. They may have formed in a subcritical context by the blocking of material on the stoss side. We do not interpret them as antidune or “chute-and-pool” structures. The dimensions and cross-stratification patterns of transverse dune bedforms are interpreted as resulting from low competence currents with a significant deposition rate, but we rule out their interpretation as “antidunes”. A similar conclusion holds for lunate dune bedforms, whose curved shape results from a sedimentation rate dependent on the thickness of the bedform. Finally, two-dimensional dune bedforms were formed where lateral transport exceeds longitudinal transport; i.e., in areas where currents were able to spread laterally in low velocity zones. We suggest that the aggrading ash bedsets with upstream crest migration were formed under subcritical flow conditions where the tractional bedload transport was less important than the simultaneous fallout from suspension. This produced differential draping with no further reworking. We propose the name “regressive climbing dunes” for structures produced by this process. A rapid decrease in current velocity, possibly triggered by hydraulic jumps affecting the entire parent flows, is inferred to explain their deposition. This process can in principle hold for any kind of particulate density current.Electronic supplementary materialThe online version of this article (doi:10.1007/s00445-013-0762-x) contains supplementary material, which is available to authorized users.

Depositional features of co-genetic turbidite–debrite beds and possible mechanisms for their formation in distal lobated bodies beyond the base-of-slope, Ulleung Basin, East Sea (Japan Sea)

Abstract A detailed analysis of the MR1 (11–12 kHz) sonar images, chirp (2–7 kHz) profiles, core sediments and 14 C ages from the latest Quaternary lobated bodies (LB) on the deep (> 2100 m water depth) basin plain of the western Ulleung Basin reveals depositional features and context of co-genetic turbidite–debrite beds in the LB on the distal setting and a plausible mechanism for generating these beds. Eight LB are present in the basin plain, ca. 30–60 km beyond the base-of-slope, and were generally deposited retrogressively. Older and more distal LB 1–4 have large dimensions (> 27 km long, 15–25 km wide). In contrast, younger and less distal LB 5–8 are small (8.8–31.5 km long, 1.2–12 km). The muddier, larger LB 1 and 2 were most likely originated from the relatively large-scale sediment failures on the muddy upper slopes (> 350–400 m water depth) between 18.5 and 20.0 cal. ka B.P. On other hand, the sandier, smaller LB 6 and 7 were deposited between 17.0 and 17.5 cal. ka B.P., probably by the relatively small-scale sediment failures on the sandy uppermost slope, shallower than 350–400 m water depth. In LB 1, a lower sandy-mud turbidite is transitional upward into an upper mud-matrix debrite having small, rounded mud clasts. In contrast, LB 6 exhibits a gradual upward change from a lower clay-poor, sandy turbidite to an upper clay-rich, sand-matrix debrite with large, interlocking mud clasts. Each mixed bed in LB 1 and 6 can represent a co-genetic (or linked) turbidite–debrite bed formed by the down-dip flow transformation from turbidity current to debris flow at a point during the same event. The abundant large-scale (up to 20–25 m deep, 3–5 km long) erosions of fine-grained substrates near the base-of-slope area suggest that the down-dip transformation was driven by incorporation of mud via erosional bulking by turbidity currents reaching the base-of-slope area. The different clay/sand content and size/shape of mud clasts in the co-genetic turbidite–debrite beds between LB 1 and 6 imply that the composition (sandy or muddy) and dimension of initial turbidity current approaching the base-of-slope, the volume of eroded masses from the fine-grained substrates, and the transport distance of sediment gravity flows from the erosional areas of muddy substrates can be all important factors controlling the depositional styles of co-genetic turbidite–debrite beds.

Three-Dimensional Architecture of the Rod Sensory Cilium and Its Disruption in Retinal Neurodegeneration

Defects in primary cilia lead to devastating disease because of their roles in sensation and developmental signaling but much is unknown about ciliary structure and mechanisms of their formation and maintenance. We used cryo-electron tomography to obtain 3D maps of the connecting cilium and adjacent cellular structures of a modified primary cilium, the rod outer segment, from wild-type and genetically defective mice. The results reveal the molecular architecture of the cilium and provide insights into protein functions. They suggest that the ciliary rootlet is involved in cellular transport and stabilizes the axoneme. A defect in the BBSome membrane coat caused defects in vesicle targeting near the base of the cilium. Loss of the proteins encoded by the Cngb1 gene disrupted links between the disk and plasma membranes. The structures of the outer segment membranes support a model for disk morphogenesis in which basal disks are enveloped by the plasma membrane.

“Stuck”: Removal of Embedded Distal Airway Foreign Bodies

Objective: 1) Describe a novel technique for removal of embedded distal airway foreign bodies. 2) Apply the proximal endoscopic balloon dilation technique for removal of embedded distal airway foreign bodies in 2 patients. 3) Discuss the evolution, operative considerations, and future applications of the technique Method: Report of 2 cases in 2011. Condition studied: Embedded, symptomatic distal airway foreign bodies. Subjects studied: Pediatric airway patients. Setting: Tertiary care pediatric hospital. Intervention: Rigid bronchoscopy with endoscopic balloon dilation of the proximal bronchial segment to facilitate access to the foreign body. Outcomes: Successful foreign body removal. Results: Case 1: A 23-month-old patient with recurrent pneumonia. Rigid bronchoscopy showed a cashew piece in the distal airway with proximal edema preventing removal. Dilation of the proximal bronchial segment with a Fogarty catheter allowed for access and removal with optical forceps. Case 2: Two-year-old unrestrained passenger in a motor vehicle accident with tooth aspiration causing intermittent respiratory distress. At bronchoscopy, the tooth was in the distal airway and embedded in granulation tissue which prevented removal. A Fogarty catheter was used to dilate the bronchial segment proximal to the foreign body which was then removed with optical forceps. Conclusion: Embedded airway foreign bodies are associated with edema and granulation tissue which may prevent removal due to proximal airway narrowing. We present a novel technique using a Fogarty balloon catheter to dilate the airway proximal to the foreign body. This allows for removal of otherwise stuck distal airway foreign bodies.

A Whole Organ Culture Model for Intervertebral Disk Using Rat Tail Explants in a Rotating Bioreactor

IntroductionIntervertebral disk (IVD) disorders resulting in pain and disability are extremely prevalent and current treatment options do not restore tissue integrity or function. Mechanisms of IVD degeneration are not fully understood. As such, in vitro culture models are being used to investigate these mechanisms. Models using cells deprived of extracellular matrix (ECM) result in loss of differentiation and viability (Haschtmann 2006) and limit the use of important outcome measures, such as biomechanics. While tissue culture of IVD explants allows for maintenance of cell morphology, preservation of ECM, and biomechanical testing, the biologic and biomechanical influences of endplate cartilage and bone are lost (Ariga 2003). For these reasons, our goal is to develop and validate a whole organ culture model. Ideally, this model will provide long-term maintenance of cell and tissue integrity, architecture, composition, viability, allow for clinically relevant assessment of IVD health, and disease. To our knowledge, few studies on whole organ culture for the study of IVD disorders have been published and none have established a validated model addressing the optimal criteria outlined above. Therefore, the objective of this study was to investigate a novel methodology for IVD whole organ culture using biological and biomechanical assessments. Materials and MethodsUnder ACUC approval, tails were collected from mature Sprague Dawley rats (n = 12) euthanatized for reasons unrelated to this study. Soft tissues were aseptically removed from the caudal vertebrae. Bone-disc-bone explants were prepared by sawing the proximal and distal vertebral bodies in half. Explants were randomly assigned to either the injured group (n = 20) in which the posterolateral annulus fibrosus (AF) was penetrated with a 20G needle to enter the nucleus pulposus (NP), which was aspirated with a 1 mL syringe to 0.5 mL, or the uninjured group (n = 22), which received no insult. Explants were cultured in a rotating bioreactor (Synthecon) at 50 rpm for 14 days in supplemented DMEM + ITS media. Culture media were changed on days 1 and 7. Cell viability in each IVD was determined using calcein-AM and ethidium homodimer-1 at day 0, 1, 7, and 14. IVDs were fixed and processed for histology and stained with hematoxylin eosin (HE), Safranin-O and Trichrome, and assessed by a pathologist, blinded to treatment, for cell and tissue morphology and architecture. Biomechanical testing of explants was performed at days 0 (after injury) and 14 by loading in axial compression at 0.001 mm/s. Stiffness was determined from the linear regions of the force-displacement curves. ResultsUninjured AF and NP cells maintained high viability through day 14. Injured AF and NP cells showed high viability at day 1, but viability in injured AF and NP cells was notably lower at days 7 and 14. Histologically, uninjured IVDs maintained normal characteristics of cells and ECM through day 14. Uninjured IVDs retained more collagen in AF and proteoglycan in NP. Injured IVDs show histologic evidence of cell death corresponding to areas of loss of cell viability and loss of proteoglycan staining in NP and loss of collagen staining in AF. Stiffness for uninjured IVDs was similar at days 0 (80.8 ± 34.8 N/mm) and 14 (89.2 ± 23.1 N/mm), while stiffness of injured IVDs was lower than the uninjured group at day 0 immediately after injury (52.9 ± 1.7 N/mm) and then increased approximately 2.5 times by day 14 (130.8 ± 37.0 N/mm) ConclusionThe results of this study suggest that whole organ (bone-disc-bone) IVD explants can be cultured in a rotating bioreactor such that cell viability and tissue architecture in AF and NP are maintained for at least 14 days. The injury used in this model produced pathologic changes in AF and NP similar to those seen in human IVD degeneration, including cell death, abnormal ECM, and increased stiffness over time. In light of previous studies that reported significant loss of cell viability using other culture models (Gawri 2011), we suggest that the use of the rotating bioreactor is critical for providing nutrient supply to IVD explants, thus preserving biologic and biomechanical properties. We were able to perform multiple outcome measures on explants to assess IVD physiology and pathology. Ongoing research in our laboratories is aimed at further optimizing this model to investigate mechanisms of disease and test therapeutic interventions.I confirm having declared any potential conflict of interest for all authors listed on this abstractYesDisclosure of InterestNone declared