Finger-like Extension Research Articles

701 LEFT ATRIAL APPENDAGE CONGENITAL ABSENCE AND ATRIAL FIBRILLATION

Abstract Introduction Left atrial appendage (LAA) is a finger-like muscular extension of the left atrium (LA). It acts as blood reservoir, modulates LA pressure and elicits adaptive responses to stress. Several LAA shapes and variants have been described. We report a case of congenital absence of LAA diagnosed by transesophageal echocardiography (TEE) and confirmed by computed tomography (CT). Case report A 55-year-old male patient with history of hypertension was admitted to our hospital for an episode of atrial fibrillation (AF). TEE was performed and showed normal LA volume, absence of thrombi and spontaneous echo contrast in the LA, but, despite acquiring three-dimensional (3D) en-face views, we were unable to identify LAA. Congenital absence of LAA was suspected and multidetector cardiac CT confirmed the abnormality. Discussion Congenital absence of LAA is an extremely rare condition: only eighteen cases were described on a review of the literature published in 2020. Associations with other congenital abnormalities or with atrial fibrillation have been reported, but a causal relationship cannot be established. Multiple imaging modalities can be used to define the anatomy and function of LAA, to detect or rule out in situ thrombosis and to guide catheter-based therapies, but the most widely used technique is TEE. Among intracardiac thrombi in patients with non-valvular atrial fibrillation, more than 90% are identified in the LAA, meaning that the remaining 10% may develop in other sites of the LA. The congenital absence of LAA could be considered similar to LAA percutaneous occlusion or surgical exclusion; because of the few published randomized controlled trials, the current ESC guidelines on atrial fibrillation are unclear about the true thrombotic risk in these cases. Since LAA percutaneous occlusion is actually indicated only in cases of contraindications for long-term anticoagulant treatment, in our opinion in patients with non-valvular AF, LAA congenital absence, high stroke risk and low bleeding risk, anticoagulant therapy should be considered. Conclusion Congenital absence of LAA is an extremely rare condition and its pathophysiological role, especially with regard to antithrombotic therapy in patients with AF, is still not well defined.

Rehearsal simulation to determine the size of device for left atrial appendage occlusion using patient-specific 3D-printed phantoms

Left atrial appendage (LAA) occlusion (LAAO) is used to close the finger-like extension from the left atrium with occlusion devices to block the source of thrombosis. However, selection of the devices size is not easy due to various anatomical changes. The purpose of this study is patient-specific, computed tomography angiography (CTA)-based, three-dimensionally (3D) printed LAAO phantoms were applied pre-procedure to determine the size. Ten patients were enrolled prospectively in March 2019 and December 2020. The cardiac structure appearing in CTA was first segmented, and the left atrium and related structures in the LAAO procedure were modeled. The phantoms were fabricated using two methods of fused deposition modeling (FDM) and stereolithography (SLA) 3D printers with thermoplastic polyurethane (TPU) and flexible resin materials and evaluated by comparing their physical and material properties. The 3D-printed phantoms were directly used to confirm the shape of LAA, and to predict the device size for LAAO. In summary, the shore A hardness of TPU of FDM was about 80–85 shore A, and that of flexible resin of SLA was about 50–70 shore A. The measurement error between the STL model and 3D printing phantoms were 0.45 ± 0.37 mm (Bland–Altman, limits of agreement from − 1.8 to 1.6 mm). At the rehearsal, the estimations of device sizes were the exact same with those in the actual procedures of all 10 patients. In conclusion, simulation with a 3D-printed left atrium phantom could be used to predict the LAAO insertion device size accurately before the procedure.

Left Atrial Appendage Depth and Tachycardia Bradycardia Syndrome as Important Predictors of Left Atrial Appendage Thrombus in Patients with Nonvalvular Atrial Fibrillation.

Background Atrial fibrillation (AF) is the most common heart rhythm disorder that has been shown to be associated with a significant increase in stroke and systemic embolism risk. The left atrial appendage (LAA) is a finger-like extension originating from the left atrium; the formation of thrombus in LAA is the main reason of stroke and systemic embolism in patients with nonvalvular atrial fibrillation (NVAF). This study is aimed at finding out the risk of left atrial appendage thrombus (LAAT) in patients with nonvalvular atrial fibrillation (NVAF). Method We retrospectively examined the clinic and left atrial computer tomography angiography (CTA) features of patients assessed in Zhengzhou No. 7 People's Hospital between January 2020 and January 2021 derivation. Student's t-test, chi-square test, receiver operating characteristics (ROC) curves, and logistic regression analysis were used to identify predictors of LAAT. Result Of 480 patients included in the analysis, LAAT was found in approximately 9.2% of all patients. Univariate demographic predictors of LAAT included left atrium top and bottom diameter (LTD), left atrial appendage depth (LAAD), CHA2DS2-VASc, tachycardia bradycardia syndrome (TBS), and nonparoxysmal atrial fibrillation (PAF). In a multiple logistic regression analysis, the independent predictors of thrombus were LAAD > 23.45 mm (odds ratio: 4.216, 95% CI: 1.869-9.510, P = 0.001), TBS (odds ratio: 4.076, 95% CI: 1.655-10.038, P = 0.002), and non-PAF (odds ratio: 2.896, 95% CI: 1.183-7.094, P = 0.02). Conclusion In NVAF patients with LAAT, evidence suggested that larger LAAD, non-PAF, and TBS present a high risk of LAAT. This is the first report demonstrating that the LAAD and TBS are associated with LAAT in patients with NVAF.

An Interpretation of the Impact of the Wisconsin Glaciation on the Hemileuca Maia/Nevadensis Complex (Saturniidae) of the Great Lakes Region

The biology of the Hemileuca maia group of “buck moths” in the Great Lakes region is summarized, especially with respect to the northern “maia complex” where adult phenotype is not well-correlated with either pheromone response or perceived host plant associations. Published field trials of pheromone response are updated with respect to host plant associations. We found a reciprocal lack of response to pheromone between willow-feeding “complex” moths in lowland, glaciated habitats to the north and oak-feeding populations in non-glaciated habitats to the south. We discuss how post-glacial host plant distributions — expansion from previous refugia and forestation of the Great Lakes terrain — may have played a key role in structuring current Great Lakes Hemileuca populations. In addition, the subsequent rapid and extreme drying during the mid-Holocene (8,000–3,200 years BP) led to the expansive tall grass prairie, producing a finger-like eastern extension known as the Prairie Peninsula, which probably provided an additional ecological barrier separating these oak and willow-feeding populations. Rapid expansion of willow-feeding populations from Pleistocene refugia after 18,000 years BP offers a more likely explanation, compared to gene flow, for the general lack of genetic divergence previously found in the buck moths of the Great Lakes region.

Evaluation of Local Tissue Reaction After the Application of a 3D Printed Novel Holdfast Device for Left Atrial Appendage Exclusion

The left atrial appendage (LAA) is a small, finger-like extension of the left atrium and its exclusion is used as a treatment strategy to prevent ischemic stroke. Existing holdfast devices may damage the tissue, are unisized and not adjustable. A novel holdfast device for LAA exclusion devoid of these shortcomings was designed and 3D-printed using the Selective Laser Sintering (SLS) technology with polyamide powder and tested it on animal model. We selected the SLS 3D printing technology due to its wid14e availability and low production costs which could provide on-site 3D printing for specific patient. The purpose of this study was to evaluate the biocompatibility of the reported holdfast device and compare the histological results obtained for local tissue reactions to those obtained for an established grafting material. Thirty swine subdivided into two groups were examined. The LAA exclusion device was implanted and was either coated with a polyester vascular implant or not coated at all and the histological response to the device’s presence was evaluated which is a standard approach to test the device biocompatibility. In all cases, complete occlusion was seen without any pathological findings during the incubation time. In both groups, the surface of the atrium under a holdfast device was smooth and shiny and had no clots. The foreign body reaction of the LAA holdfast device made of polyamide powder was insignificantly lower compared to the polyester graft. Thus, it fulfils the parameters of biocompatibility at the highest degree, and makes it suitable material for the manufacturing of LAA holdfast devices.

Bysmatrum austrafrum sp. nov. (Dinophyceae), a novel tidal pool dinoflagellate from South Africa

:A new species of the dinoflagellate genus Bysmatrum was isolated from tidal pool samples originating from Cape Peninsula, South Africa. This new species was investigated by light, scanning and transmission electron microscopy, and its phylogenetic affinities were analyzed using molecular data. Cells were pentagonal in ventral view, 25–45 μm long and 20–42.5 μm wide and only slightly flattened in a dorsiventral plane. The epitheca, in apical view, was almost circular, with a slight ventral depression. Plate tabulation (PO, X, 4′, 3a, 7″, 6c, 4s, 5′′′, 2′′′′) was typical for the genus Bysmatrum. Apical plate 1′ was heptagonal and broadly asymmetric, with an elongated, fingerlike extension at the base. The intercalary plates 2a and 3a were separated by a direct connection between plates 3′ and 4″. The thecal plates were perforated by pores of different sizes and ornamented with linearly arranged reticulations. Intercalary bands were smooth, and antapical plates were not indented. This new species differs from the five other known species of the genus Bysmatrum in morphology (e.g. the shape of apical plate 1′) and it occupies an isolated position in phylogenetic trees inferred by analyses of small-subunit ribosomal DNA (SSU-rDNA) sequence data. This also represents the first report of the SSU rDNA sequence for Bysmatrum arenicola.

IT-26 * IDENTIFICATION OF PSEUDO-PROGRESSION IN NEW DIAGNOSED GLIOBLASTOMA (GBM) IN A RANDOMIZED PHASE 2 OF ICT-107: MRI AND PATHOLOGY CORRELATION

BACKGROUND: Previously reports of pseudo-progression in patients with brain tumor after therapeutic vaccines in pediatric and adult glioma (Pollack, JCO online on June 2, 2014 and Okada, JCO Jan 20, 2011; 29: 330-336) demonstrated that RANO criteria for tumor progression may not be adequate for immunotherapy trials. Similar observations were also seen in other checkpoint inhibitor in melanoma and NSLSC. METHODS: We identified 2 patients, who developed tumor progression by RANO criteria, underwent surgery following enrollment in a phase 2 randomized ICT-107 (an autologous vaccine consisting of patient dendritic cells pulsed with peptides from AIM-2, TRP-2, HER2/neu, IL-13Ra2, gp100, MAGE1) after radiation and Temozolomide (TMZ). RESULTS: The first case is a 69 years old Chinese male, who underwent 1st surgery of gross total resection right occipital GBM on 10/26/2011. Subsequently he received 19 cycles of TMZ and 9 vaccines/placebo. MRI from 7/2/2013 showed enhancement surrounding surgical cavity. After 2nd surgery, pathology showed only rare residual tumor cells with macrophages and positive CD 8 cells. He continued on this vaccine program and MRI showed more progression with finger-like extension into parietal lobe 4 months later. The 3rd surgery also showed extensive reactive changes with no active tumor cells. For 2nd case, a 62 years old male, who underwent first surgery on 7/11/2011 of right temporal lobe, developed 2 areas of enhancement after 6 cycles of TMZ and 7 vaccines/placebo on 4/18/2012. With 2nd surgery, pathology showed reactive gliosis without active tumor. The subject continued in this trial. CONCLUSION: Pseudo-progression was confirmed by pathology in these 2 patients at 20 and 9 months which were delayed comparing to pseudo-progression observed in patients treated with concurrent XRT/TMZ (3-6 months). Future iRANO criteria development is essential for immunotherapy trials. Accurately identifying and managing such patients is necessary to avoid premature termination of therapy.

Architectural subdivisions of medial and orbital frontal cortices in the marmoset monkey (Callithrix jacchus)

Although the common marmoset has become a model for the study of several neurological conditions that affect the frontal lobe, knowledge of the boundaries of the areas located in the orbital and medial frontal regions has remained incomplete. Here we examined histological sections stained for myelin, Nissl substance, and cytochrome oxidase, allowing identification of likely homologues of most of the architectural fields defined in Old World monkeys. Ventrally, we identified three granular fields at or near the frontal pole (area 10, and the medial and lateral subregions of area 11), and two granular fields along the lateral margin of the orbitofrontal cortex (medial and orbital subdivisions of area 12). More caudal and medially, dysgranular and agranular cortices included four subdivisions of area 13 as well as rostral and caudal subdivisions of area 14 (at the ventromedial convexity). The ventral frontotemporal transition encompassed at least two subdivisions of agranular insular cortex, as well as the likely homologues of the gustatory cortices. Most of the medial surface was encompassed by area 10 (which projected a caudomedial finger-like extension toward the subgenual cortex), together with a relatively large dysgranular area 32 and an agranular area 25 (in subgenual cortex). Finally, the caudal limit of the medial frontal cortex included two fields of agranular cingulate cortex (areas 24a and 24b). These findings enhance our understanding of the architectural organization of the marmoset frontal cortex and highlight a highly conserved basic organization across simian primates, allowing the informed interpretation of experimental neurological studies.

Solid pseudopapillary neoplasm: pathological diagnosis and distinction from other solid cellular tumours of the pancreas

Solid pseudopapillary neoplasm (SPN) is a rare pancreatic tumour with low malignant potential. It is clinically distinct from other pancreatic tumours, and the proper diagnosis is crucial for patient management. However, the histological features of SPN are variable and its diagnosis is not always straightforward. Finger-like extension of the tumour into the surrounding pancreatic parenchyma, a perpendicular cell arrangement around blood vessels and indented vesicular nuclei are characteristic histological features of SPN. The lobulated solid cell pattern seen in SPN is easily mistaken for pancreatic endocrine tumour. Immunohistochemically, SPN is consistently positive for vimentin and CD56, negative or focally positive for cytokeratin and synaptophysin, and always negative for chromogranin. Diffuse nuclear expression of β-catenin is useful for the diagnosis. The distinction of SPN from other solid cellular neoplasms can be made by careful histological observation as well as using a panel of immunohistochemical markers.

TH‐D‐224C‐08: Dose Variation Within Lung Tumor and in Its Fingerlike Extension as a Function of Incident Photon Angle

Purpose: Report the dose variation within a lung tumor and its finger‐like extension as a function of incident photon beam angle. Method and Materials: A phantom with 3‐cm diameter acrylic sphere (tumor) inside a cork medium was designed so that the sphere could be rotated. TLDs were placed at various locations within the sphere and just outside the sphere. The outer TLDS simulated the tumor's finger like extension. Two 2.8cm thick acrylic plates (chest wall) sandwiched the phantom. The TLDS were exposed to a 6 MV beam of 10×10 cm2 with the sphere centered at isocenter (100 SAD). The field size was such that the dose at the periphery of the acrylic sphere was not influenced by the beam penumbra. The exposures were repeated at every 30° of the fingerlike extension with respect to the incident beam angle. The doses at the TLDs were also calculated using MCNPX Monte Carlo codes and CC convolution algorithm. Results: The measured and calculated doses were normalized to the dose at the center of the sphere. Then ratios of MC and convolution values to measured values were calculated and plotted as a histogram. The standard deviations for MC and convolution to TLD ratios were 3.5% and 1.1% respectively. The standard deviations of random error in TLD, MC and convolution methods were 2, 3 and 1.5% respectively. Conclusions: MC and CC convolution values agreed well with measured data. The data would be presented as function of incident beam angle. In addition, analysis of a PB algorithm and an 18 MV beam data would be presented.

Comparative morpho-anatomical studies of the female gonoduct within the Pratylenchidae (Nematoda: Tylenchina)

AbstractThe cellular morphology of the gonoduct of six Pratylenchus species, three Pratylenchoides species, Radopholus similis, Zygotylenchus guevarai, Hirschmanniella loofi and Nacobbus aberrans was revealed by dissection and light microscopy. Except for Nacobbus aberrans, all studied species show an overall similarity in gonoduct construction, i.e., an ovary often ending with a ring of cells, an oviduct formed from two rows of four cells and a 12-celled spermatheca followed by a tricolumella containing 16-24 cells. Pratylenchoides magnicauda and Z. guevarai did not diverge from the other Pratylenchidae in this respect, although their gonoduct differs from that of Amplimerlinius and Meloidogyne, both formerly postulated as related genera. The spermatheca structure observed in N. aberrans has not been reported elsewhere in the Nematoda, although the uterus is similar to that reported within the Heteroderinae and Meloidogyninae and the uterus comprises more than 300 cells, enlarging from a tricolumella to a polycolumella. Transmission electron microscopy of Z. guevarai revealed details of the cytoplasmatic contact between epithelial cells and the germ cells; a finger-like ovarian wall cell extension was found penetrating the oocyte. The oviduct lacks a preformed lumen and comprises eight cells with highly plicated cell membranes. The spermatheca is constructed from flattened wall cells and is followed by columnar uterus cells where evidence of eggshell formation was demonstrated.

On the transition between adhesive and cohesive modes of debonding during peeling of thin plates bonded with an epoxide adhesive

A transition from an adhesive mode of debonding at low debonding rate to a cohesive mode at high debonding rate was observed when peeling assemblies consisting of thin metallic plates bonded with an epoxide adhesive. Stable cohesive debonding was found to be characterised by a river pattern aspect of the debond surfaces and by an increase of the apparent debonding resistance with increasing debond extension. Mechanisms are proposed for the initiation and extension of cohesive debonding. Second phase nodules in the adhesive are shown to be the sites of nucleation of cavities. Initiation of cohesive debonding is ascribed to the onset of this cavitation, which is promoted by the increase of the adhesive yield strength with straining rate. Cohesive debond extension is analysed in terms of a meniscus instability mechanism whereas the R-curve behaviour is related to the finger-like extension of the debond front.

Submillimeter Polarimetric Observations of the Galactic Center

We report the first detection of polarized submillimeter emission from the Sagittarius A region at the Galactic center. We observed three separate 2' × 2' fields: one centered on the circumnuclear disk, one centered on the peak of the molecular cloud M-0.02-0.07 (also called the "50 km s-1 cloud"), and one centered on the peak of the molecular cloud M-0.13-0.08 (also called the "20 km s-1 cloud"). Linear polarization at λ = 350 μm was detected in each of the three regions, at a total of 106 distinct sky positions. In the circumnuclear disk, the projected magnetic field directions that we infer from our measurements are similar to those inferred from previous far-infrared (λ = 100 μm) polarimetry. In the "curved ridge" region of M-0.02-0.07 that has been compressed by the expansion of Sgr A East, our results show clearly the effects of this compression on the magnetic field. In M-0.13-0.08, we observe what appears to be a stretched magnetic field, as expected for this tidally sheared cloud. It has been suggested that a "finger-like extension" or "streamer" from M-0.13-0.08 is falling into the circumnuclear disk. We tentatively interpret a flaring of magnetic field lines that we see in M-0.13-0.08 as evidence that the entire cloud has a velocity component in the Galactic eastern direction, i.e., toward the circumnuclear disk. Further observations are needed to test this interpretation. We argue that polarimetry of dust emission provides a promising tool for obtaining new information on the complex dynamics of neutral gas in the Galactic center.

Synaptic exocytosis of dense-core vesicles in blue crab (Callinectes sapidus) stomach muscles.

Neuromuscular terminals of a single motoneuron to four muscles (CPV7a, GM5a, CV2, and CV3) in the stomach of the blue crab Callinectes sapidus showed structural evidence for the exocytotic release of dense-core vesicles exclusively at synapses. The primary evidence was the appearance of dense cores in the synaptic cleft, accompanied by indentations of the presynaptic or postsynaptic membrane. In their simplest form, these consisted of an omega-shaped figure of the presynaptic membrane enclosing one dense core, denoting release of a single dense-core vesicle. A larger indentation of the presynaptic membrane enclosing several dense cores denoted multiple release. A more complex form of multiple release was where the presynaptic membrane was normal, but the postsynaptic membrane elaborated into a sac projecting into the granular sarcoplasm and filled with dense cores. The postsynaptic sac in some instances was compressed into a thin, fingerlike extension, which lacked dense cores and, at its distal end, separated into small cisternae, suggesting a mechanism for membrane recycling. Profiles depicting single and multiple releases of dense-core vesicles were found more frequently at neuromuscular terminals that release relatively large amounts of transmitter with a single stimulus, such as CV2 and CV3, compared to those releasing smaller amounts, such as CPV7a and GM5a. The disparity in release sites among the four muscles of this single motor unit and the fact that many of the multiple-release figures were closely adjacent to the active zones for transmitter release suggest a possible modulatory role for dense-core vesicles in synaptic transmission. Such modulation may be long lasting, as implied by the postsynaptic sacs, which may permit prolonged release of the contents of their dense cores into the synaptic cleft. This is in keeping with the functional role of these stomach muscles, which is to be continuously active for long periods of time.

A finger-like extension of the 20 kilometer per second cloud toward the Galactic center

High-resolution ammonia-line images of the M − 0.13 − 0.08 («20 km s −1 ») cloud in the Galactic center region have been obtained with the Nobeyama Millimeter Array. The 20 km s −1 cloud has a finger-like structure extending toward the Galactic center. It almost reaches to the circumnuclear ring (disk) surrounding Sgr A West in projection. A large systematic velocity gradient (5-10 km s −1 arcmin −1 ) along the elongation is found over the whole length of the cloud. We suggest that these characteristics are caused by tidal force in the gravitational field of the Galactic center.

Electronmicroscopic studies on arterial blood vessels of the spleen, especially their relation to the reticuloendothelial system.

1) Electron-microscopic findings of the vascular system of the spleen and its relationship to the reticuloendothelial system are described. 2) In the white pulp, fine arterial blood vessels branch from the follicular artery and form a rich plexus of slender capillaries. The follicular arterioles are essentially similar in their fine structure to the arterioles of other organs. 3) The marginal zone of the white pulp is composed of phagocytic reticulum cells. Perifollicular sinusoids are poorly developed in the mouse spleen, but in the dog spleen wide perifollicular spaces form a boundary between the white and red pulp. Its basement membrane is broken in places and the wall is infiltrated by lymphoid cells, thrombocytes and erythrocytes. 4) Sheathed artery is found in the dog spleen. Sheath cells can be regarded as one of the phagocytic reticulum cells, which are differentiated from adventitial cells. 5) A large part of the terminal branches of the vascular system in the red pulp seem to end in a structure resembling a so-called finger-like extension. The basement membrane disappears abruptly and the edge of the vascular channel is structurally open. The open ending is protected by thrombocytes and reticulum cells.